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Section 1.10 : Common Graphs
7. Without using a graphing calculator sketch the graph of $$W\left( x \right) = {{\bf{e}}^{x + 2}} - 3$$.
Hint : The Algebraic transformations that we used to help us graph the first few graphs in this section can be used together to shift the graph of a function both up/down and right/left at the same time.
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The Algebraic transformations we were using in the first few problems of this section can be combined to shift a graph up/down and right/left at the same time. If we know the graph of $$g\left( x \right)$$ then the graph of $$g\left( {x + c} \right) + k$$ is simply the graph of $$g\left( x \right)$$ shifted right by $$c$$ units if $$c < 0$$ or shifted left by $$c$$ units if $$c > 0$$ and shifted up by $$k$$ units if $$k > 0$$ or shifted down by $$k$$ units if $$k < 0$$.
So, in our case if $$g\left( x \right) = {{\bf{e}}^x}$$ we can see that,
$W\left( x \right) = {{\bf{e}}^{x + 2}} - 3 = g\left( {x + 2} \right) - 3$
and so the graph we’re being asked to sketch is the graph of $$g\left( x \right) = {{\bf{e}}^x}$$shifted left by 2 units and down by 3 units.
Here is the graph of $$W\left( x \right) = {{\bf{e}}^{x + 2}} - 3$$ and note that to help see the transformation we have also sketched in the graph of $$g\left( x \right) = {{\bf{e}}^x}$$.
In this case the resulting sketch of $$W\left( x \right)$$ that we get by shifting the graph of $$g\left( x \right)$$ is not really the best, as it pretty much cuts off at $$x = 0$$ so in this case we should probably extend the graph of $$W\left( x \right)$$ a little. Here is a better sketch of the graph. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.41528743505477905, "perplexity": 285.27564930829857}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764500304.90/warc/CC-MAIN-20230206051215-20230206081215-00833.warc.gz"} |
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# The inside of a rectangular carton is 48 centimeters long, 3
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The inside of a rectangular carton is 48 centimeters long, 32 centimeters wide, and 15 centimeters high. The carton is filled to capacity with k identical cylindrical cans of fruit that stand upright in rows and columns, as indicated in the figure above. If the cans are 15 centimeters high, what is the value of k?
(1) Each of the cans has a radius of 4 centimeters.
(2) Six of the cans fit exactly along the length of the carton.
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Re: The inside of a rectangular carton is 48 centimeters long, 3 [#permalink]
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03 Sep 2012, 05:14
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SOLUTION
The inside of a rectangular carton is 48 centimeters long, 32 centimeters wide, and 15 centimeters high. The carton is filled to capacity with k identical cylindrical cans of fruit that stand upright in rows and columns, as indicated in the figure above. If the cans are 15 centimeters high, what is the value of k?
(1) Each of the cans has a radius of 4 centimeters --> radius=4 means that diameter=8, which implies that along the 48 centimeter length of the carton 48/8=6 cans can be placed and along the 32 centimeter width of the carton 32/8=4 cans can be placed. Thus, k=6*4=24. Sufficient.
(2) Six of the cans fit exactly along the length of the carton --> the diameter of the can is 48/6=8 centimeters. So, we have the same info as above. Sufficient.
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Re: The inside of a rectangular carton is 48 centimeters long, 3 [#permalink]
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03 Sep 2012, 05:23
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Bunuel wrote:
The inside of a rectangular carton is 48 centimeters long, 32 centimeters wide, and 15 centimeters high. The carton is filled to capacity with k identical cylindrical cans of fruit that stand upright in rows and columns, as indicated in the figure above. If the cans are 15 centimeters high, what is the value of k?
(1) Each of the cans has a radius of 4 centimeters.
(2) Six of the cans fit exactly along the length of the carton.
Since Height of Box and Height of Cans are equal so only one stack of cans is there in the box. No need to bother about height.
So inside dimensions of Box = 48 X 32
St 1: Sufficient: Each can has radius of 4 = Dia is 8 cms. ie (48/8) 6 nos of cans can be in one row. And since cans are identical (32/8) ie 4 cans can fit in colums. So 24 nos of can can fit in box.
St 2: Sufficient: 6 cans can fit along the length. ie dia of each can = 48/6 ie 8 cms. As discussed in St 1.
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Re: The inside of a rectangular carton is 48 centimeters long, 3 [#permalink]
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07 Sep 2012, 05:22
SOLUTION
The inside of a rectangular carton is 48 centimeters long, 32 centimeters wide, and 15 centimeters high. The carton is filled to capacity with k identical cylindrical cans of fruit that stand upright in rows and columns, as indicated in the figure above. If the cans are 15 centimeters high, what is the value of k?
(1) Each of the cans has a radius of 4 centimeters --> radius=4 means that diameter=8, which implies that along the 48 centimeter length of the carton 48/8=6 cans can be placed and along the 32 centimeter width of the carton 32/8=4 cans can be placed. Thus, k=6*4=24. Sufficient.
(2) Six of the cans fit exactly along the length of the carton --> the diameter of the can is 48/6=8 centimeters. So, we have the same info as above. Sufficient.
Kudos points given to everyone with correct solution. Let me know if I missed someone.
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Re: The inside of a rectangular carton is 48 centimeters long, 3 [#permalink]
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24 Apr 2013, 01:53
Bunuel wrote:
SOLUTION
The inside of a rectangular carton is 48 centimeters long, 32 centimeters wide, and 15 centimeters high. The carton is filled to capacity with k identical cylindrical cans of fruit that stand upright in rows and columns, as indicated in the figure above. If the cans are 15 centimeters high, what is the value of k?
(1) Each of the cans has a radius of 4 centimeters --> radius=4 means that diameter=8, which implies that along the 48 centimeter length of the carton 48/8=6 cans can be placed and along the 32 centimeter width of the carton 32/8=4 cans can be placed. Thus, k=6*4=24. Sufficient.
(2) Six of the cans fit exactly along the length of the carton --> the diameter of the can is 48/6=8 centimeters. So, we have the same info as above. Sufficient.
Kudos points given to everyone with correct solution. Let me know if I missed someone.
I know the measurement of the carton, which is 48*32. Now the can's radius is 4 cm. Although the height of the carton is the same as the height of the cans i.e. 15, which I am ignoring as it will eventually cancel out in the calculation. My question is around the solution that is provided in the O.G. They have simply divided the length of the carton by diameter and width by diameter and then further multiplied the result.
(48/8)*(32/8)
=6*4
=24.
Btw I got the right answer since its a DS problem. I am worried coz had this been a p.s problem, I might have got this one wrong.
Now the way I would have solved this is
1st find the circumference of the circle (eliminating the height as the it is same). 2IIr=2*22/7*4
and then divided it by (48*32)/(176/7). My answer in this case is different from the OA =61.09
Why II (pie) was not considered. Why circumference was not considered instead of diameter. I failed to understand this. Can you please explain this.
Further when I use a formula for rectangle's area =L*B, where both lenght and breadth is present. But in case of circle I don't have a II(pie) anywhere. Why do we use this. What is the significance of II (pie).
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Re: The inside of a rectangular carton is 48 centimeters long, 3 [#permalink]
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24 Apr 2013, 04:38
davidfrank wrote:
Bunuel wrote:
SOLUTION
The inside of a rectangular carton is 48 centimeters long, 32 centimeters wide, and 15 centimeters high. The carton is filled to capacity with k identical cylindrical cans of fruit that stand upright in rows and columns, as indicated in the figure above. If the cans are 15 centimeters high, what is the value of k?
(1) Each of the cans has a radius of 4 centimeters --> radius=4 means that diameter=8, which implies that along the 48 centimeter length of the carton 48/8=6 cans can be placed and along the 32 centimeter width of the carton 32/8=4 cans can be placed. Thus, k=6*4=24. Sufficient.
(2) Six of the cans fit exactly along the length of the carton --> the diameter of the can is 48/6=8 centimeters. So, we have the same info as above. Sufficient.
Kudos points given to everyone with correct solution. Let me know if I missed someone.
I know the measurement of the carton, which is 48*32. Now the can's radius is 4 cm. Although the height of the carton is the same as the height of the cans i.e. 15, which I am ignoring as it will eventually cancel out in the calculation. My question is around the solution that is provided in the O.G. They have simply divided the length of the carton by diameter and width by diameter and then further multiplied the result.
(48/8)*(32/8)
=6*4
=24.
Btw I got the right answer since its a DS problem. I am worried coz had this been a p.s problem, I might have got this one wrong.
Now the way I would have solved this is
1st find the circumference of the circle (eliminating the height as the it is same). 2IIr=2*22/7*4
and then divided it by (48*32)/(176/7). My answer in this case is different from the OA =61.09
Why II (pie) was not considered. Why circumference was not considered instead of diameter. I failed to understand this. Can you please explain this.
Further when I use a formula for rectangle's area =L*B, where both lenght and breadth is present. But in case of circle I don't have a II(pie) anywhere. Why do we use this. What is the significance of II (pie).
Why are you calculating the circumference?
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Re: The inside of a rectangular carton is 48 centimeters long, 3 [#permalink]
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24 Apr 2013, 17:15
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Straight forward question. You need to get the radius of the cylinders to get the number of cylinders. Both A and B help to calculate r. D wins.
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Re: The inside of a rectangular carton is 48 centimeters long, 3 [#permalink]
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26 Apr 2013, 21:38
Bunuel wrote:
davidfrank wrote:
Bunuel wrote:
SOLUTION
The inside of a rectangular carton is 48 centimeters long, 32 centimeters wide, and 15 centimeters high. The carton is filled to capacity with k identical cylindrical cans of fruit that stand upright in rows and columns, as indicated in the figure above. If the cans are 15 centimeters high, what is the value of k?
(1) Each of the cans has a radius of 4 centimeters --> radius=4 means that diameter=8, which implies that along the 48 centimeter length of the carton 48/8=6 cans can be placed and along the 32 centimeter width of the carton 32/8=4 cans can be placed. Thus, k=6*4=24. Sufficient.
(2) Six of the cans fit exactly along the length of the carton --> the diameter of the can is 48/6=8 centimeters. So, we have the same info as above. Sufficient.
Kudos points given to everyone with correct solution. Let me know if I missed someone.
I know the measurement of the carton, which is 48*32. Now the can's radius is 4 cm. Although the height of the carton is the same as the height of the cans i.e. 15, which I am ignoring as it will eventually cancel out in the calculation. My question is around the solution that is provided in the O.G. They have simply divided the length of the carton by diameter and width by diameter and then further multiplied the result.
(48/8)*(32/8)
=6*4
=24.
Btw I got the right answer since its a DS problem. I am worried coz had this been a p.s problem, I might have got this one wrong.
Now the way I would have solved this is
1st find the circumference of the circle (eliminating the height as the it is same). 2IIr=2*22/7*4
and then divided it by (48*32)/(176/7). My answer in this case is different from the OA =61.09
Why II (pie) was not considered. Why circumference was not considered instead of diameter. I failed to understand this. Can you please explain this.
Further when I use a formula for rectangle's area =L*B, where both lenght and breadth is present. But in case of circle I don't have a II(pie) anywhere. Why do we use this. What is the significance of II (pie).
Why are you calculating the circumference?
Hi Bunuel,
I am calculating the circumference because I know the area of the rectangular (ignoring the height 15 cm as it is common to both can and carton). Once I know the area, I can divide the area by circumference of the circle to know the no of cans.
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Re: The inside of a rectangular carton is 48 centimeters long, 3 [#permalink]
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27 Apr 2013, 04:32
davidfrank wrote:
Bunuel wrote:
davidfrank wrote:
I know the measurement of the carton, which is 48*32. Now the can's radius is 4 cm. Although the height of the carton is the same as the height of the cans i.e. 15, which I am ignoring as it will eventually cancel out in the calculation. My question is around the solution that is provided in the O.G. They have simply divided the length of the carton by diameter and width by diameter and then further multiplied the result.
(48/8)*(32/8)
=6*4
=24.
Btw I got the right answer since its a DS problem. I am worried coz had this been a p.s problem, I might have got this one wrong.
Now the way I would have solved this is
1st find the circumference of the circle (eliminating the height as the it is same). 2IIr=2*22/7*4
and then divided it by (48*32)/(176/7). My answer in this case is different from the OA =61.09
Why II (pie) was not considered. Why circumference was not considered instead of diameter. I failed to understand this. Can you please explain this.
Further when I use a formula for rectangle's area =L*B, where both lenght and breadth is present. But in case of circle I don't have a II(pie) anywhere. Why do we use this. What is the significance of II (pie).
Why are you calculating the circumference?
Hi Bunuel,
I am calculating the circumference because I know the area of the rectangular (ignoring the height 15 cm as it is common to both can and carton). Once I know the area, I can divide the area by circumference of the circle to know the no of cans.
It seems that you don't understand the question. You need neither circumference of the cans nor the area.
Simpler example might help:
Attachment:
Untitled.png [ 10.24 KiB | Viewed 7083 times ]
The carton is 16 centimeters long and 16 centimeters wide. If the diameter of the cans is 8 centimeters, how many cans can be placed in the carton?
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Re: The inside of a rectangular carton is 48 centimeters long, 3 [#permalink]
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05 Oct 2014, 18:40
When I did this problem, I inadvertinly read over the specification desigmating, width, length and height. In this case 15 was the height, allowing us to cram the most amount of cyclinder cans.
Here is my question, if height was not deginated as 15 in the case, would the solution be E? ie, we have the 15×32×48 dimensions but we don't know what is length, width, height. E is what I came up with.
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The inside of a rectangular carton is 48 centimeters long, 3 [#permalink]
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15 Mar 2016, 22:17
We only need the radius of the can to answer the question. Both the statements give the radius of the cans . So both are sufficient. D is the answer.
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Re: The inside of a rectangular carton is 48 centimeters long, 3 [#permalink]
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09 Aug 2016, 12:47
Quote:
Attachment:
Carton.png
The inside of a rectangular carton is 48 centimeters long, 32 centimeters wide, and 15 centimeters high. The carton is filled to capacity with k identical cylindrical cans of fruit that stand upright in rows and columns, as indicated in the figure above. If the cans are 15 centimeters high, what is the value of k?
(1) Each of the cans has a radius of 4 centimeters.
(2) Six of the cans fit exactly along the length of the carton.
We are given that a rectangular carton has a length of 48 cm, a width of 32 cm, and a height of 15 cm. We are also given that there are k identical cylindrical cans standing upright in this carton, and each can has a height of 15 cm. We need to determine the value of k, or the total number of cans in the carton.
Because we have the dimensions of the carton, if we are able to determine the diameter of each can, then we will be able to determine the value of k.
Statement One Alone:
Each of the cans has a radius of 4 centimeters.
Since the diameter is twice the radius we know that the diameter of each can is 8 cm. This is enough information to determine how many cans fit in the carton. Although we do not have to determine the actual value of k (because this is a data sufficiency problem), let’s determine it anyway.
Since the length of the carton is 48 cm we could fit 48/8 = 6 cans along the length of the carton, and since the width of the carton is 32 cm, we could fit 32/8 = 4 cans along the width of the carton.
Thus the carton could hold a total of 6 x 4 = 24 cans. Statement one alone is sufficient to answer the question. We can eliminate answer choices B, C and E.
Statement Two Alone:
Six of the cans fit exactly along the length of the carton.
In a similar fashion to the process used in statement one, we can use the information in statement two to determine the diameter of each can.
(Length of carton)/(diameter of each can) = number of cans that fit along the length of the carton
48/d = 6
48 = 6d
d = 8
Since we have the diameter of each can, we have enough information to determine how many total cans fit in the carton. Statement two alone is also sufficient to answer the question.
Note that because we have the length of the carton as 48 centimeters, statements 1 and 2 are giving us the same information – the length of the diameter or radius of each can. Whenever the two statements give the same information, the answer has to be D or E. It can’t be A or B because if one statement is sufficient (or insufficient), the other is too. It can’t be C because neither statement is adding information to the other. So as soon as we realized that A was sufficient in this question, we would know the answer is D.
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Re: The inside of a rectangular carton is 48 centimeters long, 3 [#permalink] 09 Aug 2016, 12:47
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Display posts from previous: Sort by | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.826141357421875, "perplexity": 1501.8755797481997}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-50/segments/1480698541517.94/warc/CC-MAIN-20161202170901-00122-ip-10-31-129-80.ec2.internal.warc.gz"} |
https://www.tutorialspoint.com/in-place-move-zeros-to-end-of-list-in-python | # In-place Move Zeros to End of List in Python
PythonServer Side ProgrammingProgramming
Suppose we have a list of numbers nums, we have to put all the zeros to the end of the list by updating the list in-place. And the relative ordering of other elements should not be changed. We have to try to solve this in O(1) additional space.
So, if the input is like [2,0,1,4,0,5,6,4,0,1,7], then the output will be [2, 1, 4, 5, 6, 4, 1, 7, 0, 0, 0]
To solve this, we will follow these steps −
• if size of L is same as 0, then
• return a blank list
• k := 0
• for i in range 0 to size of L, do
• if L[i] is not same as 0, then
• L[k] := L[i]
• k := k + 1
• for j in range k to size of L, do
• L[j] := 0
• return L
Let us see the following implementation to get better understanding −
## Example
Live Demo
class Solution:
def solve(self, L):
if len(L) == 0:
return []
k = 0
for i in range(len(L)):
if L[i] != 0:
L[k] = L[i]
k+=1
for j in range(k,len(L)):
L[j] = 0
return L
ob = Solution()
L = [2,0,1,4,0,5,6,4,0,1,7]
print(ob.solve(L))
## Input
[2,0,1,4,0,5,6,4,0,1,7]
## Output
[2, 1, 4, 5, 6, 4, 1, 7, 0, 0, 0]
Published on 23-Sep-2020 07:15:51 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.32097822427749634, "perplexity": 2191.9009397363657}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323585204.68/warc/CC-MAIN-20211018155442-20211018185442-00609.warc.gz"} |
http://kb.osu.edu/dspace/handle/1811/19242 | # LASER ABSORPTION SPECTROSCOPY OF HYDROCARBON FLAMES
Please use this identifier to cite or link to this item: http://hdl.handle.net/1811/19242
Files Size Format View
1999-MF-04.jpg 107.2Kb JPEG image
Title: LASER ABSORPTION SPECTROSCOPY OF HYDROCARBON FLAMES Creators: Cheskis, Sergey; Derzy, Igor; Lozovsky, Vladimir A. Issue Date: 1999 Publisher: Ohio State University Abstract: Intracavity Laser Absorption Spectroscopy (ICLAS) and Cavity Ring-Down Spectroscopy (CRDS) were used to detect absorption spectra of $CH(C^{2}\Sigma^{-}\leftarrow X^{2}\Pi)$ at 314 nm, $^{1}CH_{2} (\bar{b}^{1}B_{1}\leftarrow \tilde{a}^{1}A_{1})$ at $590$ and $620 nm, NH (A^{3}\Pi,\leftarrow X^{3}\Sigma^{-})$ at $336 nm$, and $NH_{2} (\bar{A}^{2}A_{1}\leftarrow \bar{X}^{2}B_{1})$ at $598 nm$ in a low-pressure (30 Torr) stoichiometric methane/oxygen/nitrogen flat flame doped with a small amount of nitrous oxide. The CH and NH radicals were monitored by CRDS whereas $^{1}CH_{2}$ and $NH_{2}$ were monitored by ICLAS. The absolute concentration profiles of those radicals were measured. The radical absorption spectra were recorded with good signal-to-noise ratio. The spectra of the $^{1}CH_{2}$ radical were measured in different spectral ranges that allowed us better determination of its absorption cross section. For the first time the absolute concentrations of NH and $NH_{2}$ were measured in the flames of this kind. The agreement between experimental results and model predictions based on the GRI-Mech 2.11 mechanism is discussed. URI: http://hdl.handle.net/1811/19242 Other Identifiers: 1999-MF-04 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5906566381454468, "perplexity": 4523.715047134082}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-23/segments/1406510280868.21/warc/CC-MAIN-20140728011800-00421-ip-10-146-231-18.ec2.internal.warc.gz"} |
https://economictheoryblog.com/2016/02/21/linear-regression-in-r/ | Linear Regression in R
R presents various ways to carry out linear regressions. The most natural way is to use the lm() function, the R build-in OLS estimator. In this post I will present you how to use lm() and run OLS on the following model
$y = \alpha + \beta_{1} x_{1} + \beta_{2} x_{2} + \beta_{3} x_{3}$
The lm() function requires you to specify the model and to indicate the object containing the data. You have to specify the model in lm() the following way
$y \sim x_{1} + x_{2} + x_{3}$
where $y, x_{1}, x_{2}$ and $x_{3}$ are replaced with the variables names.
The model would look the following way when specified in R. I assume that the data is stored in a data frame named df.
## use R build-in OLS estimaor (lm())
reg <- lm(y ~ x1 + x2 + x3, data=df)
summary(reg)
Furthermore, R offers several additional function in order to evaluate the regression output. Some of these post-regression functions are listed below
# several other useful functions
coefficients(reg) # show coefficients
anova(reg) # show anova table
vcov(reg) # show covariance matrix for model parameters
confint(reg, level=0.95) # CIs for model parameters
regted(reg) # show fitted values
residuals(reg) # show residuals
influence(reg) # show diagnostics
Finally, the lm() function is a complete wrapper around the OLS estimator in R. It provides little inside of the calculations carried out in the background. In the following post I rebuild the OLS estimator from scratch using R. I go through every single step of the calculations and provide estimates of the coefficients, standard errors and p-values. Finally, I incorporate the presented code into a function and show that the function returns the same results as lm(). The manually constructed function can be found here.
3 thoughts on “Linear Regression in R”
This site uses Akismet to reduce spam. Learn how your comment data is processed. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 4, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7381097674369812, "perplexity": 1382.657710343666}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-27/segments/1656104248623.69/warc/CC-MAIN-20220703164826-20220703194826-00482.warc.gz"} |
http://mathhelpforum.com/advanced-algebra/113496-nulls-ranges.html | 1. Nulls and Ranges
I got a question here that states:
Suppose that p belongs to L(V) and P² = P, show that V = nullP is a direct sum of rangeP.
Could anyone give me a rough idea on how to approach this question? Thanks for any help.
2. Originally Posted by GreenDay14
I got a question here that states:
Suppose that p belongs to L(V) and P² = P, show that V = nullP is a direct sum of rangeP.
Could anyone give me a rough idea on how to approach this question? Thanks for any help.
For any x in V, x = Px + (x–Px). Notice that Px is in ran(P), and x–Px is in null(P).
To complete the proof, you also have to show that $\text{ran}(P)\cap\text{null}(P) = \{0\}$. So suppose that y = Px and that Py = 0. Can you deduce that y = 0? | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 1, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.95927494764328, "perplexity": 611.3635881492854}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-50/segments/1480698543316.16/warc/CC-MAIN-20161202170903-00080-ip-10-31-129-80.ec2.internal.warc.gz"} |
https://www.physicsforums.com/threads/a-little-electronics-question-about-logical-gates.563984/ | # A little electronics question about logical gates
1. Dec 31, 2011
### Femme_physics
Last edited by a moderator: May 5, 2017
2. Dec 31, 2011
### ehild
Last edited by a moderator: May 5, 2017
3. Dec 31, 2011
### Femme_physics
Last edited by a moderator: May 5, 2017
4. Dec 31, 2011
### ehild
Re: A little electronics question about logical gates....
Well, OR adds the inputs. But the symbol for an OR gate is not what you drew. It is spiky. Do you mean an OR or an AND gate?
ehild
Last edited: Dec 31, 2011
5. Dec 31, 2011
### Femme_physics
Re: A little electronics question about logical gates....
Oh, I mean an AND gate, then. sorry.
6. Dec 31, 2011
### ehild
Re: A little electronics question about logical gates....
In that case, erase that "OR".
And then the output is correct, but can be simplified.
ehild
7. Dec 31, 2011
### Femme_physics
Last edited by a moderator: May 5, 2017
8. Dec 31, 2011
### ehild
Re: A little electronics question about logical gates....
Let's start with the basic things. How are the logical addition, multiplication and negation defined?
ehild
9. Dec 31, 2011
### I like Serena
Re: A little electronics question about logical gates....
Hi Fp!
Perhaps you would like to try to fill out the following table?
$$\begin{array}{|c|c|c|c|c|c|c|c|} a & b & c & ab & \overline{ab} & \overline{ab} c & cc & \overline{ab} c + cc \\ \hline \\ 0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 \\ 0 & 0 & 1 & 0 & 1 & & & \\ 0 & 1 & 0 & 0 & 1 & & & \\ 0 & 1 & 1 & 0 & & & & \\ 1 & 0 & 0 & 0 & & & & \\ 1 & 0 & 1 & 0 & & & & \\ 1 & 1 & 0 & 1 & & & & \\ 1 & 1 & 1 & & & & & \\ \hline \end{array}$$
Last edited: Dec 31, 2011
10. Dec 31, 2011
### I like Serena
Re: A little electronics question about logical gates....
Good point, edited.
I don't like how Latex shows it though.
11. Dec 31, 2011
### I like Serena
Re: A little electronics question about logical gates....
Just found it myself too ;) Fixed it.
12. Jan 1, 2012
### Femme_physics
Re: A little electronics question about logical gates....
Well, it depends on the scenario. What bridge are we talking about? What function do we have?
I did my own, similar one, a while ago.... except I didn't include AC(capped)
http://img684.imageshack.us/img684/4424/chart3u.jpg [Broken]
And this is how I got F
http://img402.imageshack.us/img402/7498/chart1ar.jpg [Broken]
I presume 1+1 reboots the thing and makes it 0?
Last edited by a moderator: May 5, 2017
13. Jan 1, 2012
### Curious3141
Re: A little electronics question about logical gates....
A truth table is the most basic way to do it, but it is tedious. This is very easy to simplify using the basic laws of Boolean algebra (BA).
Let's review some basic rules of BA. Let x be a binary variable.
How would you simplify xx?
What is (x + 1)? (1 + x)?
What is x.1? 1.x?
Last edited by a moderator: May 5, 2017
14. Jan 1, 2012
### Curious3141
Re: A little electronics question about logical gates....
Some entries are wrong. For instance 1 + 1 is not 0, but 1. Remember that '+' here signifies the OR function.
Last edited by a moderator: May 5, 2017
15. Jan 1, 2012
### Femme_physics
Re: A little electronics question about logical gates....
Well, we were told to always do truth tables since we're just beginners.
X^2
2X + X^2 +1
That would be 1 times x? that's X.
Did not know that! So,
http://img225.imageshack.us/img225/5489/fscan.jpg [Broken]
Last edited by a moderator: May 5, 2017
16. Jan 1, 2012
### I like Serena
Re: A little electronics question about logical gates....
"xx" represents "x AND x".
Do you know what that is?
"x+1" represents "x OR 1", which is?
"1x" represents "1 AND x".
But yes, that would be the same as x.
Yes!
Can you see which columns are identical to F?
Last edited by a moderator: May 5, 2017
17. Jan 1, 2012
### Femme_physics
Re: A little electronics question about logical gates....
Multiplication.
Addition.
Also multiplication!
Yes, CC. But, we only know how to simplify using Karno Map (translating the name from Hebrew).
So,
http://img576.imageshack.us/img576/92/image201201010014.jpg [Broken]
Last edited by a moderator: May 5, 2017
18. Jan 1, 2012
### Curious3141
Re: A little electronics question about logical gates....
OK, so the above Truth Table is now correct. Do you see that the output is exactly $c$? The output is 0 when $c=0$ and 1 when $c=1$. So the simplified final answer is just $c$.
Here's how to see that by doing the Boolean Algebra. I'm going to answer my own post here:
$xx$ (can also be written $x.x$) $= (x AND x) = x$. This is because when x = 0, 0 AND 0 = 0, and when x = 1, 1 AND 1 = 1.
$(x+1) = (x OR 1) = (1+x) = (1 OR x) = 1$. A '1' OR anything (or vice versa) is still '1'. This line also demonstrates commutativity of addition (the OR function).
$(1.x) = (1 AND x) = (x.1) = (x AND 1) = x$. A '1' AND anything (or vice versa) depends wholly on x, as you can see from the truth table for AND. This line also demonstrates commutativity of multiplication (the AND function).
OK, so back to the problem. The first line uses the distributive law over multiplication (AND), which you already seem to know. It is used again in regrouping terms.
$$(\bar{ab}+c).c = \bar{ab}c + c.c = \bar{ab}c + c = (\bar{ab}+1).c = 1.c = c$$
See how easy that was?
As a final note, please don't get confused between binary number addition and the Boolean OR, and binary number multplication and the Boolean AND. As an exercise you may want to work out the other simple rules in Boolean Algebra, (the ones for 0.x, 0 + x, and maybe inspect the slight complexities of the XOR function, and culminating in doing your own proof of De Morgan's Laws).
Last edited by a moderator: May 5, 2017
19. Jan 2, 2012
### Femme_physics
Re: A little electronics question about logical gates....
Thanks Curious! We actually only studied Boolean Algebra yesterday! I know how to tackle it all now :) if I'll run into any problems I'll post back. Thanks everyone :)
20. Jan 2, 2012
### Femme_physics
Last edited by a moderator: May 5, 2017
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http://mathematica.stackexchange.com/questions/50781/filling-between-two-curves-in-mathematica | # Filling between two curves in Mathematica [closed]
I want to fill region between 2 curves, but in Mathematica 8.0:
FilledListPlot[list1, list2, Fills -> {RGBColor[f, f, f]}]
doesn't work.
-
## migration rejected from math.stackexchange.comJun 14 '14 at 14:52
This question came from our site for people studying math at any level and professionals in related fields. Votes, comments, and answers are locked due to the question being closed here, but it may be eligible for editing and reopening on the site where it originated.
## closed as off-topic by Öskå, Yves Klett, Artes, Mr.Wizard♦Jun 14 '14 at 14:52
This question appears to be off-topic. The users who voted to close gave this specific reason:
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If this question can be reworded to fit the rules in the help center, please edit the question.
Please try Plot[{Sin[x], Cos[x]}, {x, 0, 2 Pi}, Filling -> {1 -> {{2}, Yellow}}] – Claude Leibovici Jun 14 '14 at 12:40
– Artes Jun 14 '14 at 13:39
\$Version
"8.0 for Mac OS X x86 (64-bit) (October 5, 2011)"
Needs["PlotLegends"];
m = 6;
list1 = Table[2^(n - 2.5), {n, m}];
list2 = Table[Fibonacci[n], {n, m}];
ListLinePlot[
{list1, list2},
PlotStyle -> Thick,
Filling -> (1 -> {2}),
FillingStyle -> {LightRed, LightBlue},
(* color by which list value is greater *)
PlotLegend -> {"list1", "list2"},
LegendPosition -> {-.2, -.1},
` | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.16343525052070618, "perplexity": 7077.070396776948}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-18/segments/1429246654114.44/warc/CC-MAIN-20150417045734-00217-ip-10-235-10-82.ec2.internal.warc.gz"} |
https://emplatform.eu/publications/details?id=423 | Funding
EMP is funded through the Horizon2020 programme of the European Commission.
Selected Publications
## Magnonic Analog of Black- and White-Hole Horizons in Superfluid 3He-B
M. Clovečko, E. Gažo, M. Kupka, and P. Skyba,
We report on the theoretical model and experimental results of the experiment made in a limit of absolute zero temperature (600μK) studying the spin wave analog of black- and white-hole horizons using spin (magnonic) superfluidity in superfluid 3HeB. As an experimental tool simulating the properties of the black- and white-hole horizons, we used the spin-precession waves propagating on the background of the spin supercurrents between two Bose-Einstein condensates of magnons in the form of homogeneously precessing domains. We provide experimental evidence of the white hole formation for spin precession waves in this system, together with the observation of an amplification effect. Moreover, the estimated temperature of the spontaneous Hawking radiation in this system is about 4 orders of magnitude lower than the system’s background temperature which makes it a promising tool for studying the effect of spontaneous Hawking radiation.
Phys. Rev. Lett. 123, 161302 (2019)
doi: 10.1103/PhysRevLett.123.161302
arxiv: https://arxiv.org/abs/1810.09890 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9051249623298645, "perplexity": 1608.067995449303}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764499826.71/warc/CC-MAIN-20230130165437-20230130195437-00060.warc.gz"} |
https://cantera.org/documentation/docs-2.1/doxygen/html/PseudoBinaryVPSSTP_8cpp.html | Cantera 2.1.2
PseudoBinaryVPSSTP.cpp File Reference
Definitions for intermediate ThermoPhase object for phases which employ excess gibbs free energy formulations (see Thermodynamic Properties and class PseudoBinaryVPSSTP). More...
#include "cantera/thermo/PseudoBinaryVPSSTP.h"
#include "cantera/base/stringUtils.h"
#include <cstdio>
Include dependency graph for PseudoBinaryVPSSTP.cpp:
Go to the source code of this file.
## Namespaces
Cantera
Namespace for the Cantera kernel.
## Detailed Description
Definitions for intermediate ThermoPhase object for phases which employ excess gibbs free energy formulations (see Thermodynamic Properties and class PseudoBinaryVPSSTP).
Header file for a derived class of ThermoPhase that handles variable pressure standard state methods for calculating thermodynamic properties that are further based upon expressions for the excess gibbs free energy expressed as a function of the mole fractions.
Definition in file PseudoBinaryVPSSTP.cpp. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3457871675491333, "perplexity": 8183.687635497506}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-45/segments/1603107872746.20/warc/CC-MAIN-20201020134010-20201020164010-00303.warc.gz"} |
https://mathoriginal.com/algebra/logarithm/ | By Math Original No comments
##### Logarithm
Logarithm Properties
There is a close relationship between logarithms and The logarithm of a number is defined as the power or index to which a given base must be raised to obtain the number.
If we have $\displaystyle {{a}^{x}}=M$ where a and M are greater than zero and a≠1 then we can write this in a logarithm form.
$\displaystyle {{\log }_{a}}M=x$
Since logarithms are closely related with then also their properties are similar.
### Logarithm of a Product
With when you multiply two numbers with the same base you add the exponents meanwhile with logarithms the logarithm of a product is the sum of the logarithms.
The logarithm of a product is the sum of logarithms.
$\displaystyle {{\log }_{a}}(M~N)={{\log }_{a}}M+{{\log }_{a}}N$
Example 1: Use the product property to evaluate.
a) $\displaystyle {{\log }_{3}}(3\cdot 9)$
We can evaluate it directly by multiplying the product and finding the value
$\displaystyle {{\log }_{3}}(3\cdot 9)=$
$\displaystyle {{\log }_{3}}(27)=x$
$\displaystyle {{3}^{x}}=27$
$\displaystyle {{3}^{x}}={{3}^{3}}$
$\displaystyle x=3$
But our exercise is asking us to use the product property so the solution would be
$\displaystyle {{\log }_{3}}(3\cdot 9)=$
$\displaystyle {{\log }_{3}}3+{{\log }_{3}}9=$
Now we evaluate each of them separately
$\displaystyle {{\log }_{3}}3={{x}_{1}}$
$\displaystyle {{3}^{{{{x}_{1}}}}}=3$
$\displaystyle {{3}^{{{{x}_{1}}}}}={{3}^{1}}$
$\displaystyle {{x}_{1}}=1$ and $\displaystyle {{\log }_{3}}9={{x}_{2}}$
$\displaystyle {{3}^{{{{x}_{2}}}}}=9$
$\displaystyle {{3}^{{{{x}_{2}}}}}={{3}^{2}}$
$\displaystyle {{x}_{2}}=2$
So $\displaystyle {{\log }_{3}}(3\cdot 9)=$
$\displaystyle {{\log }_{3}}3+{{\log }_{3}}9=$
$\displaystyle 1+2=3$
b) $\displaystyle {{\log }_{5}}(5\cdot 25)$
We can evaluate it directly by multiplying the product and finding the value
$\displaystyle {{\log }_{5}}(5\cdot 25)=$
$\displaystyle {{\log }_{5}}(125)=x$
$\displaystyle {{5}^{x}}=125$
$\displaystyle {{5}^{x}}={{5}^{3}}$
$\displaystyle x=3$
But our exercise is asking us to use the product property so the solution would be
$\displaystyle {{\log }_{5}}(5\cdot 25)=$
$\displaystyle {{\log }_{5}}5+{{\log }_{5}}25=$
Now we evaluate each of them separately
$\displaystyle {{\log }_{5}}5={{x}_{1}}$
$\displaystyle {{5}^{{{{x}_{1}}}}}=5$
$\displaystyle {{5}^{{{{x}_{1}}}}}={{5}^{1}}$
$\displaystyle {{x}_{1}}=1$ and $\displaystyle {{\log }_{5}}25={{x}_{2}}$
$\displaystyle {{5}^{{{{x}_{2}}}}}=25$
$\displaystyle {{5}^{{{{x}_{2}}}}}={{5}^{2}}$
$\displaystyle {{x}_{2}}=2$
So $\displaystyle {{\log }_{5}}(5\cdot 25)=$
$\displaystyle {{\log }_{5}}5+{{\log }_{5}}25=$
$\displaystyle 1+2=3$
Example 2: Evaluate the sum of logarithms.
a) $\displaystyle {{\log }_{6}}2+{{\log }_{6}}3$
Finding each of them separately is difficult
$\displaystyle lo{{g}_{6}}3={{x}_{2}}$
$\displaystyle {{6}^{{{{x}_{2}}}}}=3$
And $\displaystyle {{\log }_{6}}2={{x}_{1}}$
$\displaystyle {{6}^{{{{x}_{1}}}}}=2$
Based on the rule we know that the sum of the logarithms is equal with the product of logarithm.
$\displaystyle {{\log }_{6}}2+{{\log }_{6}}3=$
$\displaystyle {{\log }_{6}}(2\cdot 3)=$
$\displaystyle {{\log }_{6}}(6)=x$
Now the logarithm form we write it on an exponential form to find the answer
$\displaystyle {{6}^{x}}=6$
$\displaystyle {{6}^{x}}={{6}^{1}}$
$\displaystyle x=1$
So $\displaystyle {{\log }_{6}}2+lo{{g}_{6}}3=1$
b) $\displaystyle {{\log }_{2}}3+{{\log }_{2}}\frac{4}{3}$
Finding each of them separately is difficult
$\displaystyle {{\log }_{2}}3={{x}_{1}}$
$\displaystyle {{2}^{{{{x}_{1}}}}}=3$ and $\displaystyle {{\log }_{2}}\frac{4}{3}={{x}_{2}}$
$\displaystyle {{2}^{{{{x}_{2}}}}}=\frac{4}{3}$
Based on the rule we know that the sum of the logarithms is equal with the product of logarithm.
$\displaystyle {{\log }_{2}}(3\cdot \frac{4}{3})=$
$\displaystyle {{\log }_{2}}3+{{\log }_{2}}\frac{4}{3}=$
$\displaystyle {{\log }_{2}}4=x$
Now the logarithm form we write it on an exponential form to find the answer
$\displaystyle {{2}^{x}}=4$
$\displaystyle {{2}^{x}}={{2}^{2}}$
$\displaystyle x=2$
So $\displaystyle {{\log }_{2}}3+{{\log }_{2}}\frac{4}{3}=2$
Note! If the product has many factors, you just add the individual logarithms.
If $\displaystyle {{x}_{1}}>0,{{x}_{2}}>0,…….,{{x}_{n}}>0$ then
$\displaystyle {{\log }_{a}}({{x}_{1}}\cdot {{x}_{2}}…….{{x}_{n}})={{\log }_{a}}{{x}_{1}}+{{\log }_{a}}{{x}_{2}}+………+{{\log }_{a}}{{x}_{n}}$
Logarithm of a Quotient
With exponents when you divide two numbers with the same base you subtract the exponents meanwhile with logarithms the logarithm of a quotient is the difference of the logarithms.
The logarithm of a quotient is the difference of the logarithms.
$\displaystyle {{\log }_{a}}\left( {\frac{M}{N}} \right)={{\log }_{a}}M-{{\log }_{a}}N$
Example 3: Use the quotient property to evaluate.
a) $\displaystyle {{\log }_{2}}\left( {\frac{{32}}{8}} \right)$
We can evaluate it directly by dividing the quotient and finding the value
$\displaystyle {{\log }_{2}}\left( {\frac{{32}}{8}} \right)=$
$\displaystyle {{\log }_{2}}(4)=x$
$\displaystyle {{2}^{x}}=4$
$\displaystyle {{2}^{x}}={{2}^{2}}$
$\displaystyle x=2$
But our exercise is asking us to use the quotient property so the solution would be
$\displaystyle {{\log }_{2}}\left( {\frac{{32}}{8}} \right)=$
$\displaystyle {{\log }_{2}}32-{{\log }_{2}}8=$
Now we evaluate each of them separately
$\displaystyle {{\log }_{2}}32={{x}_{1}}$
$\displaystyle {{2}^{{{{x}_{1}}}}}=32$
$\displaystyle {{\log }_{2}}32={{x}_{1}}$
$\displaystyle {{2}^{{{{x}_{1}}}}}=32$
$\displaystyle {{2}^{{{{x}_{1}}}}}={{2}^{5}}$
$\displaystyle {{x}_{1}}=5$ and $\displaystyle {{\log }_{2}}8={{x}_{2}}$
$\displaystyle {{2}^{{{{x}_{2}}}}}=8$
$\displaystyle {{2}^{{{{x}_{2}}}}}={{2}^{3}}$
$\displaystyle {{x}_{2}}=3$
So $\displaystyle {{\log }_{2}}\left( {\frac{{32}}{8}} \right)=$
$\displaystyle {{\log }_{2}}32-{{\log }_{2}}8=$
$\displaystyle 5-3=2$
b) $\displaystyle {{\log }_{7}}\left( {\frac{{49}}{{2401}}} \right)$
We can evaluate it directly by dividing the quotient and finding the value
$\displaystyle {{\log }_{7}}\left( {\frac{{49}}{{2401}}} \right)=$
$\displaystyle {{\log }_{7}}\left( {\frac{1}{{49}}} \right)=x$
$\displaystyle {{7}^{x}}=\frac{1}{{49}}$
$\displaystyle {{7}^{x}}={{49}^{{-1}}}$
$\displaystyle {{7}^{x}}={{7}^{{-2}}}$
$\displaystyle x=-2$
But our exercise is asking us to use the quotient property so the solution would be
$\displaystyle {{\log }_{7}}\left( {\frac{{49}}{{2401}}} \right)=$
$\displaystyle {{\log }_{7}}49-{{\log }_{7}}2401=$
Now we evaluate each of them separately
$\displaystyle {{\log }_{7}}49={{x}_{1}}$
$\displaystyle {{7}^{{{{x}_{1}}}}}=49$
$\displaystyle {{7}^{{{{x}_{1}}}}}={{7}^{2}}$
$\displaystyle {{x}_{1}}=2$ and $\displaystyle {{\log }_{7}}2401={{x}_{2}}$
$\displaystyle {{7}^{{{{x}_{2}}}}}=2401$
$\displaystyle {{7}^{{{{x}_{2}}}}}={{7}^{4}}$
$\displaystyle {{x}_{2}}=4$
So $\displaystyle {{\log }_{7}}\left( {\frac{{49}}{{2401}}} \right)=$
$\displaystyle {{\log }_{7}}49-{{\log }_{7}}2401=$
$\displaystyle 2-4=-2$
Example 4: Evaluate the difference of logarithms.
a) $\displaystyle {{\log }_{3}}7-{{\log }_{3}}\frac{7}{9}$
Finding each of them separately is difficult
$\displaystyle {{\log }_{3}}7={{x}_{1}}$
$\displaystyle {{3}^{{{{x}_{1}}}}}=7$
And $\displaystyle {{\log }_{3}}\frac{7}{9}={{x}_{2}}$
$\displaystyle {{3}^{{{{x}_{2}}}}}=\frac{7}{9}$
Based on the rule we know that the difference of the logarithms is equal with the quotient of logarithms
$\displaystyle {{\log }_{3}}7-{{\log }_{3}}\frac{7}{9}=$
$\displaystyle {{\log }_{3}}\frac{7}{{\frac{7}{9}}}={{\log }_{3}}7\cdot \frac{9}{7}=$
$\displaystyle {{\log }_{3}}9=x$
Now the logarithm form we write it on an exponential form to find the answer
$\displaystyle {{3}^{x}}=9$
$\displaystyle {{3}^{x}}={{3}^{2}}$
$\displaystyle x=2$
So $\displaystyle {{\log }_{3}}7-{{\log }_{3}}\frac{7}{9}=2$
b) $\displaystyle {{\log }_{5}}100-{{\log }_{5}}4$
Finding each of them separately is difficult
$\displaystyle {{\log }_{5}}100={{x}_{1}}$
And $\displaystyle {{\log }_{5}}4={{x}_{2}}$
Based on the rule we know that the difference of the logarithms is equal with the quotient of logarithms
$\displaystyle {{\log }_{5}}100-{{\log }_{5}}4=$
$\displaystyle {{\log }_{5}}\frac{{100}}{4}=$
$\displaystyle {{\log }_{5}}25=x$
Now the logarithm form we write it on an exponential form to find the answer
$\displaystyle {{5}^{x}}=25$
$\displaystyle {{5}^{x}}={{5}^{2}}$
$\displaystyle x=2$
So $\displaystyle {{\log }_{5}}100-{{\log }_{5}}4=2$
Logarithm of a Power
The other property of exponents is power of a power and the similarity with logarithm property is that the power n becomes a factor.
$\displaystyle {{\log }_{a}}{{M}^{n}}=n{{\log }_{a}}M$
Example 5: Use the power property to simplify the logarithm.
a) $\displaystyle {{\log }_{2}}{{(32)}^{{12}}}$
Using the power property
$\displaystyle {{\log }_{2}}{{(32)}^{{12}}}=$
$\displaystyle 12{{\log }_{2}}(32)=$
Evaluating $\displaystyle {{\log }_{2}}(32)=x$
$\displaystyle {{2}^{x}}=32$
$\displaystyle {{2}^{x}}={{2}^{5}}$
$\displaystyle x=5$
So $\displaystyle {{\log }_{2}}{{(32)}^{{12}}}=$
$\displaystyle 12{{\log }_{2}}(32)=$
$\displaystyle 12\cdot 5=60$
b) $\displaystyle {{\log }_{9}}{{(81)}^{x}}$
Using the power property
$\displaystyle {{\log }_{9}}{{(81)}^{x}}=$
$\displaystyle x{{\log }_{9}}81=$
Evaluating $\displaystyle {{\log }_{9}}81=y$
$\displaystyle {{9}^{y}}=81$
$\displaystyle {{9}^{y}}={{9}^{2}}$
$\displaystyle y=2$
So $\displaystyle {{\log }_{9}}{{(81)}^{x}}=$
$\displaystyle x{{\log }_{9}}81=$
$\displaystyle x\cdot 2=2x$
Change of Base Property
The change of base property of logarithm says that we can rewrite a given logarithm as the ratio of two logarithms with any new base.
$\displaystyle {{\log }_{a}}x=\frac{{{{{\log }}_{b}}x}}{{{{{\log }}_{b}}a}}$
Example 6: Evaluate.
a) $\displaystyle {{\log }_{2}}7$
This type of logarithm is difficult to evaluate even with calculator, that’s why we use the change of base property to turn it with base 10.
$\displaystyle {{\log }_{2}}7=\frac{{{{{\log }}_{{10}}}7}}{{{{{\log }}_{{10}}}2}}=$
We evaluate each logarithm with calculator
$\displaystyle \frac{{\log 7}}{{\log 2}}\approx \frac{{0,84}}{{0,30}}\approx 2,8$
b) $\displaystyle {{\log }_{5}}8$
$\displaystyle {{\log }_{5}}8=\frac{{\log 8}}{{\log 5}}\approx \frac{{0,90}}{{0,70}}\approx 1,28$
Tip!
1. If a log has no base written, you should generally assume that the base is 10.
2. The logarithm to the base e ($\displaystyle {{\log }_{e}}x$) is written as $\displaystyle \ln x$.
Example 7: Simplify by using the rules of exponents and logarithms.
a) $\displaystyle \log \frac{1}{2}+\log \frac{2}{5}+\log \frac{5}{7}+\log \frac{7}{9}+\log \frac{9}{{10}}$
$\displaystyle \log \frac{1}{2}+\log \frac{2}{5}+\log \frac{5}{7}+\log \frac{7}{9}+\log \frac{9}{{10}}=$
Using the logarithm of a product rule
$\displaystyle \log (\frac{1}{2}\cdot \frac{2}{5}\cdot \frac{5}{7}\cdot \frac{7}{9}\cdot \frac{9}{{10}})=$
$\displaystyle \log (\frac{1}{{\cancel{2}}}\cdot \frac{{\cancel{2}}}{{\cancel{5}}}\cdot \frac{{\cancel{5}}}{{\cancel{7}}}\cdot \frac{{\cancel{7}}}{{\cancel{9}}}\cdot \frac{{\cancel{9}}}{{10}})=$
$\displaystyle \log (\frac{1}{{10}})=x$
$\displaystyle {{10}^{x}}=\frac{1}{{10}}$
$\displaystyle {{10}^{x}}={{10}^{{-1}}}$
$\displaystyle x=-1$
So $\displaystyle \log \frac{1}{2}+\log \frac{2}{5}+\log \frac{5}{7}+\log \frac{7}{9}+\log \frac{9}{{10}}=-1$
b) $\displaystyle {{e}^{{\ln 10-\ln 2}}}$
$\displaystyle {{e}^{{\ln 10-\ln 2}}}=$
Using Logarithm of a quotient rule
$\displaystyle {{e}^{{\ln (\frac{{10}}{2})}}}={{e}^{{\ln 5}}}=5$
c) $\displaystyle {{\log }_{2}}\frac{{8\sqrt{2}}}{{\sqrt[3]{2}}}$
Using the rules of exponents we rewrite our expression
$\displaystyle {{\log }_{2}}\frac{{8\sqrt{2}}}{{\sqrt[3]{2}}}={{\log }_{2}}\frac{{{{2}^{3}}\cdot {{2}^{{\frac{1}{2}}}}}}{{{{2}^{{\frac{1}{3}}}}}}=$
$\displaystyle {{\log }_{2}}{{2}^{{(3+\frac{1}{2}-\frac{1}{3})}}}={{\log }_{2}}{{2}^{{(\frac{{18+3-2}}{6})}}}=$
$\displaystyle {{\log }_{2}}{{2}^{{\frac{{19}}{6}}}}=\frac{{19}}{6}$
d) $\displaystyle {{\log }_{2}}\sqrt[5]{{8\sqrt[3]{2}}}$
Using the rules of exponents we rewrite our expression
$\displaystyle {{\log }_{2}}\sqrt[5]{{8\sqrt[3]{2}}}={{\log }_{2}}\sqrt[5]{{8\cdot {{2}^{{\frac{1}{3}}}}}}=$
$\displaystyle {{\log }_{2}}\sqrt[5]{{{{2}^{3}}\cdot {{2}^{{\frac{1}{3}}}}}}={{\log }_{2}}\sqrt[5]{{{{2}^{{(3+\frac{1}{3})}}}}}=$
$\displaystyle {{\log }_{2}}\sqrt[5]{{{{2}^{{(\frac{{9+1}}{3})}}}}}={{\log }_{2}}\sqrt[5]{{{{2}^{{(\frac{{10}}{3})}}}}}=$
$\displaystyle {{\log }_{2}}{{\left( {{{2}^{{(\frac{{10}}{3})}}}} \right)}^{{\frac{1}{5}}}}={{\log }_{2}}{{2}^{{(\frac{{10}}{3}\cdot \frac{1}{5})}}}=$
$\displaystyle {{\log }_{2}}{{2}^{{(\frac{{10}}{{15}})}}}={{\log }_{2}}{{2}^{{(\frac{2}{3})}}}=x$
$\displaystyle {{2}^{x}}={{2}^{{\frac{2}{3}}}}$ then $\displaystyle x=\frac{2}{3}$
So $\displaystyle {{\log }_{2}}\sqrt[5]{{8\sqrt[3]{2}}}=\frac{2}{3}$
e) $\displaystyle \frac{3}{{{{{\log }}_{2}}(2a)}}+\frac{3}{{{{{\log }}_{a}}(2a)}}$ where $\displaystyle a>1$
$\displaystyle \frac{3}{{{{{\log }}_{2}}(2a)}}+\frac{3}{{{{{\log }}_{a}}(2a)}}=$
Using the logarithm of a product rule
$\displaystyle \frac{3}{{{{{\log }}_{2}}2+{{{\log }}_{2}}a}}+\frac{3}{{{{{\log }}_{a}}2+{{{\log }}_{a}}a}}=$
We evaluate
$\displaystyle {{\log }_{2}}2=x$
$\displaystyle {{2}^{x}}={{2}^{1}}$
$\displaystyle x=1$
So $\displaystyle {{\log }_{2}}2=1$
In the same way $\displaystyle {{\log }_{a}}a=1$
Substituting we obtain
$\displaystyle \frac{3}{{1+{{{\log }}_{2}}a}}+\frac{3}{{1+{{{\log }}_{a}}2}}=$
Using the change of base rule
$\displaystyle {{\log }_{a}}2=\frac{{{{{\log }}_{2}}2}}{{{{{\log }}_{2}}a}}=\frac{1}{{{{{\log }}_{2}}a}}$
We get
$\displaystyle \frac{3}{{1+{{{\log }}_{2}}a}}+\frac{3}{{1+\frac{1}{{{{{\log }}_{2}}a}}}}=$
$\displaystyle \frac{3}{{1+{{{\log }}_{2}}a}}+\frac{3}{{\frac{{{{{\log }}_{2}}a+1}}{{{{{\log }}_{2}}a}}}}=$
$\displaystyle \frac{3}{{1+{{{\log }}_{2}}a}}+\frac{{3{{{\log }}_{2}}a}}{{1+{{{\log }}_{2}}a}}=$
$\displaystyle \frac{{3(1+{{{\log }}_{2}}a)}}{{1+{{{\log }}_{2}}a}}=$
$\displaystyle \frac{{3\cancel{{(1+{{{\log }}_{2}}a)}}}}{{\cancel{{1+{{{\log }}_{2}}a}}}}=3$
So $\displaystyle \frac{3}{{{{{\log }}_{2}}(2a)}}+\frac{3}{{{{{\log }}_{a}}(2a)}}=3$
f) $\displaystyle {{3}^{{\frac{2}{{{{{\log }}_{5}}81}}}}}$
Using the change of base rule
$\displaystyle {{\log }_{5}}3=\frac{{{{{\log }}_{3}}3}}{{{{{\log }}_{3}}5}}=\frac{1}{{{{{\log }}_{3}}5}}$
$\displaystyle {{3}^{{\frac{2}{{{{{\log }}_{5}}81}}}}}={{3}^{{\frac{2}{{{{{\log }}_{5}}{{3}^{4}}}}}}}={{3}^{{\frac{2}{{4{{{\log }}_{5}}3}}}}}$
Substituting we obtain
$\displaystyle {{3}^{{\frac{2}{{\frac{4}{{{{{\log }}_{3}}5}}}}}}}={{3}^{{\frac{{2{{{\log }}_{3}}5}}{4}}}}={{3}^{{\frac{{{{{\log }}_{3}}5}}{2}}}}$
Using logarithm of a power rule
$\displaystyle {{3}^{{{{{\log }}_{3}}{{5}^{{\frac{1}{2}}}}}}}={{5}^{{\frac{1}{2}}}}=\sqrt{5}$
So $\displaystyle {{3}^{{\frac{2}{{{{{\log }}_{5}}81}}}}}=\sqrt{5}$
g) $\displaystyle {{\log }_{{\frac{1}{9}}}}27-{{\log }_{{81}}}\frac{1}{3}$
$\displaystyle {{\log }_{{\frac{1}{9}}}}27-{{\log }_{{81}}}\frac{1}{3}=$
We can’t use the quotient rule because the bases are different.
Let’s evaluate them separately
$\displaystyle {{\log }_{{\frac{1}{9}}}}27=x$
$\displaystyle {{\left( {\frac{1}{9}} \right)}^{x}}=27$
$\displaystyle {{\left( {\frac{1}{{{{3}^{2}}}}} \right)}^{x}}=27$
$\displaystyle {{\left( {{{3}^{{-2}}}} \right)}^{x}}={{3}^{3}}$
$\displaystyle {{3}^{{-2x}}}={{3}^{3}}$ then $\displaystyle -2x=3$
$\displaystyle x=-\frac{3}{2}$
$\displaystyle {{\log }_{{81}}}\frac{1}{3}=y$ then $\displaystyle {{81}^{y}}=\frac{1}{3}$
$\displaystyle {{3}^{{4y}}}={{3}^{{-1}}}$ then $\displaystyle 4y=-1$
$\displaystyle y=-\frac{1}{4}$
Now we substitute and evaluate
$\displaystyle x-y=-\frac{3}{2}-\left( {-\frac{1}{4}} \right)=$
$\displaystyle -\frac{6}{4}+\frac{1}{4}=-\frac{5}{4}$
So $\displaystyle {{\log }_{{\frac{1}{9}}}}27-{{\log }_{{81}}}\frac{1}{3}=-\frac{5}{4}$
Remember!
$\displaystyle {{\log }_{b}}1=0$ because $\displaystyle {{b}^{0}}=1$
$\displaystyle {{\log }_{b}}b=1$ because $\displaystyle {{b}^{1}}=b$
$\displaystyle {{b}^{{{{{\log }}_{b}}x}}}=x$
$\displaystyle {{\log }_{b}}{{b}^{x}}=x$
Example 8: Find x.
a) $\displaystyle {{\log }_{2}}({{\log }_{3}}x)=5$
$\displaystyle {{\log }_{3}}x={{2}^{5}}$
$\displaystyle {{\log }_{3}}x=32$
$\displaystyle x={{3}^{{32}}}$
b) $\displaystyle {{25}^{{{{{\log }}_{5}}x}}}=x+56$
We should note that x>0
$\displaystyle {{5}^{{2{{{\log }}_{5}}x}}}=x+56$
$\displaystyle {{5}^{{{{{\log }}_{5}}{{x}^{2}}}}}=x+56$
$\displaystyle {{x}^{2}}=x+56$
$\displaystyle {{x}^{2}}-x-56=0$
$\displaystyle {{x}_{1}}=-7$ and $\displaystyle {{x}_{2}}=8$
c) $\displaystyle {{4}^{{\log x}}}\cdot {{2}^{{\log x}}}=64$
$\displaystyle {{2}^{{2\log x}}}\cdot {{2}^{{\log x}}}=64$
$\displaystyle {{2}^{{2\log x+}}}^{{\log x}}=64$
$\displaystyle {{2}^{{3\log x}}}={{2}^{6}}$
$\displaystyle 3\log x=6$
$\displaystyle \log x=2$
$\displaystyle x={{10}^{2}}$
$\displaystyle x=100$
d) $\displaystyle {{\log }_{{\frac{1}{3}}}}x=\frac{2}{{{{{\log }}_{3}}5}}$
$\displaystyle x={{\left( {\frac{1}{5}} \right)}^{{\frac{2}{{{{{\log }}_{3}}5}}}}}=$
$\displaystyle {{({{5}^{{-1}}})}^{{^{{\frac{2}{{{{{\log }}_{3}}5}}}}}}}=$
$\displaystyle {{(5)}^{{-\frac{2}{{{{{\log }}_{3}}5}}}}}=$
Changing the base rule
$\displaystyle {{\log }_{3}}5=\frac{{{{{\log }}_{5}}5}}{{{{{\log }}_{5}}3}}=\frac{1}{{{{{\log }}_{5}}3}}$
Substituting we obtain
$\displaystyle {{(5)}^{{\frac{{-2}}{{\frac{1}{{{{{\log }}_{5}}3}}}}}}}=$
$\displaystyle {{5}^{{-2{{{\log }}_{5}}3}}}=$
$\displaystyle {{5}^{{{{{\log }}_{5}}{{{(3)}}^{{-2}}}}}}=$
$\displaystyle {{3}^{{-2}}}=\frac{1}{9}$
So $\displaystyle x=\frac{1}{9}$
e) $\displaystyle {{9}^{{\ln x}}}-4\cdot {{3}^{{1+\ln x}}}+27=0$
We should note that x>0
$\displaystyle {{3}^{{2\ln x}}}-4\cdot {{3}^{1}}\cdot {{3}^{{\ln x}}}+27=0$
$\displaystyle {{3}^{{2\ln x}}}-12\cdot {{3}^{{\ln x}}}+27=0$
We substitute $\displaystyle {{3}^{{\ln x}}}=t$ and obtain a quadratic equation of the form $\displaystyle {{t}^{2}}-12t+27=0$
We find $\displaystyle {{t}_{1}}=3$ and $\displaystyle {{t}_{2}}=9$
Now we find the x-s
$\displaystyle {{3}^{{\ln {{x}_{1}}}}}=3$
$\displaystyle \ln {{x}_{1}}=1$
$\displaystyle {{x}_{1}}=e$ and $\displaystyle {{3}^{{\ln {{x}_{2}}}}}=9$
$\displaystyle {{3}^{{\ln {{x}_{2}}}}}={{3}^{2}}$
$\displaystyle \ln {{x}_{2}}=2$
$\displaystyle {{x}_{2}}={{e}^{2}}$
f) $\displaystyle {{({{\log }_{5}}20)}^{2}}={{(\log {{5}^{4}})}^{2}}+{{\log }_{5}}x$
$\displaystyle {{\log }_{5}}x={{({{\log }_{5}}20)}^{2}}-{{({{\log }_{5}}4)}^{2}}=$
$\displaystyle ({{\log }_{5}}20-{{\log }_{5}}4)({{\log }_{5}}20+{{\log }_{5}}4)$
Using the product and quotient rule
$\displaystyle ({{\log }_{5}}\frac{{20}}{4})({{\log }_{5}}20\cdot 4)=$
$\displaystyle ({{\log }_{5}}5)({{\log }_{5}}80)={{\log }_{5}}80$
$\displaystyle x=80$ | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8889352679252625, "perplexity": 785.567866659813}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-50/segments/1606141176049.8/warc/CC-MAIN-20201124082900-20201124112900-00068.warc.gz"} |
https://www.lhscientificpublishing.com/Journals/articles/DOI-10.5890-JEAM.2021.12.006.aspx | ISSN:2325-6192 (print)
ISSN:2325-6206 (online)
Journal of Environmental Accounting and Management
António Mendes Lopes (editor), Jiazhong Zhang(editor)
António Mendes Lopes (editor)
University of Porto, Portugal
Email: aml@fe.up.pt
Jiazhong Zhang (editor)
School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi Province 710049, China
Fax: +86 29 82668723 Email: jzzhang@mail.xjtu.edu.cn
Effect of Fear on Interacting Species Dynamics with Nonlinear Predator Harvesting
Journal of Environmental Accounting and Management 9(4) (2021) 403--427 | DOI:10.5890/JEAM.2021.12.006
Lakshmi Narayan Guin$^{1}$, Ayantika Mapa$^{1}$, Santabrata Chakravarty$^{2}$
Abstract
The present pursuit concerns itself with an updated real predator-prey system based on a fear factor induced by interacting species with nonlinear predator harvesting unlike constant or linear harvesting. The diversification of system parameters gives rise to different categories of system dynamics. The system under consideration does experience bifurcation (saddle-node, transcritical and Hopf-Andronov) about the co-existence equilibrium position with respect to the choice of fear factor or nonlinear harvesting factor as a parameter of significance. The direction of the Hopf bifurcation together with the stability of the bifurcating periodic solutions are perceived through an explicit algorithm duly established by making use of the normal form and central manifold theory. The findings of the present investigation reveal that the fear factor or nonlinear harvesting factor bears the potential to influence the dynamical scenario of the interacting species remarkably.
Acknowledgments
The authors would like to communicate their sincere appreciation to the anonymous referee for helpful remarks that will help to improve the quality of the paper. The first author gratefully acknowledges the financial support in part from Special Assistance Programme (SAP-III) sponsored by the University Grants Commission (UGC), New Delhi, India (Grant No. F.$510$ / $3$ / DRS-III / $2015$ (SAP-I)).
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30. [30] Wang, X., Zanette, L., and Zou, X. (2016), Modelling the fear effect in predator-prey interactions, Journal of Mathematical Biology, Springer, 73(5), 1179-1204. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.47479209303855896, "perplexity": 12860.701119387004}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296944996.49/warc/CC-MAIN-20230323034459-20230323064459-00070.warc.gz"} |
https://www.physicsforums.com/threads/help-needed-maths-thx.17453/ | # Homework Help: Help needed maths thx
1. Mar 31, 2004
### expscv
1how do i find the intersaction of sin(x) and $$\frac{2x}{\pi}$$
2 solve $$x-1 \leq \frac{1}{x-1}$$
2. Mar 31, 2004
### ahrkron
Staff Emeritus
For the intersection, plot the two functions. That will give you one of the three answers right away. The other two are trickier.
For the second, try first playing with $$y \leq \frac{1}{y}$$. You can do it "by cases", or plotting the two sides of the equation to get an idea of the whole situation.
3. Mar 31, 2004
### expscv
oh i tried that but i got 4 answers that conflict each other, i dunno about the signs of them
4. Mar 31, 2004
### expscv
and for Q1 it wasnt able to solve algerbically only draw to graph in scale and measure it~
5. Mar 31, 2004
### Zurtex
$$x-1 \leq \frac{1}{x-1}$$
If I remember correctly the algebraic way of doing this was to say:
$$0 \leq \frac{1}{x-1} - x + 1$$
Make them the same fraction and find out where they change signs (where their linear factors in the numerator and denominator equal 0)
6. Mar 31, 2004
Either way, you're going to have to multiply through by (x-1), which can be both negative or positive. The sign of (x-1) will determine which direction the inequality goes, so it is important.
So for what values of x is (x-1) positive? Negative? What solutions do these two cases (+(x-1) and -(x-1)) yield?
This is what ahrkron was getting at.
7. Mar 31, 2004
### expscv
$$x-1 \leq \frac{1}{x-1}$$
if x-1 greater than 0
$$(x-1)^2 \leq 1$$
$$(x-1)^2-1 \leq 0$$
$$x^2-2x \leq 0$$
$$x(x-2) \leq 0$$
????
if x-1 less than 0
$$(x-1)^2 \geq 1$$
$$(x-1)^2-1 \geq 0$$
$$x^2-2x \geq 0$$
$$x(x-2) \geq 0$$
????
conflict ~~~ =(
8. Mar 31, 2004
### expscv
i m now cureently study at sydney australia , the quailty there is so crap, my level of knowledge is dropping rapidly since came to sydney omg , the government do not really interested in high education, everything depends with us, we have to buy books past paper and do heaps more staff reqiued by school, and that only makes us standard compare to other country~ such a pity.
9. Mar 31, 2004
### expscv
ppl here must be older than me any suggest into my future career? thx
i m losing my second place in maths to 6th, because the arrival of oversea studnets~
what can i do to improve my self? many thx
10. Mar 31, 2004
### HallsofIvy
The intersection of the graphs of y= sin(x) and $y= \frac{2x}{\pi}$ (it's the graphs that intersect, not the functions) is where $sin(x)= \frac{2x}{\pi}$. There is no "algebraic" way to solve that but you could use any number of numerical methods: and, as ahrkron said, graphing it is simple. Plotting it on my handy-dandy TI-83 (and I remember when "four-function" calculators were big news!) I see immediately that (0,0) is one intersection and, since both functions are odd, there exist one point of intersection with x positive and one with x negative.
Zooming in on the positive-x point, It looks like it is ($\frac{\pi}{2}$, 1).
Well, yes, of course, sin($\frac{\pi}{2}$)= 1 and $\frac{2}{/pi}(\frac{\pi}{2})= 1$. Graphing shows us that there exist exactly three points of intersection and simple calculation show that they are (0,0), ($\frac{\pi}{2}$, 1), and ($-\frac{\pi}{2}$, 1).
As for the inequality: $$x-1 \leq \frac{1}{x-1}$$, I think the simplest general way to solve inequalities is to look at the equation:
$x-1 = \frac{1}{x-1}$ is the same as (x-1)2= 1 so
x-1= 1 => x= 2 or x-1= -1 => x= 0. Also the denominator of the fraction will be 0 when x-1= 0 => x= 1.
The point of that is that inequality can "change" (from "<" to ">") only where the two sides are equal or where the function is discontinuous: in this case where the denominator is 0: here at 0, 1, and 2.
If x= -1< 0, then the left side is (-1-1)= -2 and the right side is 1/(-2)= -1/2. -2< -1/2 so the inequality is true: therefore it is true for all x< 0.
If x= 1/2 (between 0 and 1), the left side is (1/2-1)=-1/2 and the right side is -2. -1/2> -2 so the inequality is false for all x between 0 and 1.
if x= 3/2 (between 1 and 2), the left side is (3/2-1)= 1/2 and the right side is 2. 1/2< 2 so the inequality is true for all x between 1 and 2.
Finally, if x= 3 (larger than 2), the left side is (3-1)= 2 and the right side is 1/2. 3> 1/2 so the inequality is false for all x> 2.
Since the problem was $\leq$, the equality is true at 0 and 2.
The inequality is true for $x\leq 0$ and $1< x \leq 2. 11. Mar 31, 2004 ### Zurtex You don't have to multiply through by [itex]x-1$ at all:
$$x-1 \leq \frac{1}{x-1}$$
$$0 \leq \frac{1}{x-1} - (x - 1)$$
$$\frac{1}{x-1} - \frac{(x-1)^2}{x-1} \geq 0$$
$$\frac{1 - (x-1)^2}{x-1} \geq 0$$
$$\frac{1- (x^2 - 2x + 1)}{x-1} \geq 0$$
$$\frac{x^2 - 2x +1 -1}{x-1} \leq 0$$
$$\frac{x(x-2)}{x-1} \leq 0$$
Critical values are $x = 0,1,2$ These are when they change signs, so as the final statement is true when $x < 0$ then:
$$x \leq 0$$
OR
$$1 < x \leq 2$$
See another way of doing it if you like
12. Mar 31, 2004
### expscv
omg how come all so smart~ thx all | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8698030710220337, "perplexity": 1309.9667039932267}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-51/segments/1544376829568.86/warc/CC-MAIN-20181218184418-20181218210418-00363.warc.gz"} |
http://math.stackexchange.com/questions/142984/the-approximation-of-set | # The approximation of set
$A,B$ are closed sets of $\mathbb R^n$ such that $A \subset {\rm{Int}}(B)$.
Is there a positive continuous function $\sigma (x)$ on $B$ such that if $f$ is a continuous function from $B$ to $\mathbb R^n$ such that $\left| {f(x) - x} \right| < \sigma (x)$, then $f(B)$ contains $A$?
-
If you are willing to weaken your demands to $\sigma(x)$ non-negative and $|f(x)-x|\leq\sigma(x)$, then $\sigma(x)=d(x,A)$ (which is defined as $\inf\{|x-a|:a\in A\}$) is such function. – Asaf Karagila May 9 '12 at 11:50
The answer to your question is "yes, there is such a function $\sigma$". First consider the special case, where $A$ consists of a single point $a\in B$:
By assumption $A\subset \mathrm{Int}(B)$, there exists $r>0$ such that the closed $r$-ball $\overline{B_r}(a)$ around $a$ is contained in $B$. It follows from Brower's fixed point theorem that $f(B_r(a)) \supset B_{r(1-\epsilon)}(a)$ if $|f(x) - x| < r\epsilon$ for all $x\in \partial B_r(a)$. Indeed, if there was $b\in B_{r(1-\epsilon)}(a)\setminus f(B_r(a))$, then the map $g: \overline{B_{r}}(a) \to \overline{B_r}(a)$ given by $$g(x) = a+r\frac{f(x) - b}{|f(x) - b|}$$ would have no fixed point, contradicting Brouwer's fixed point theorem.
This shows that for $a\in \mathrm{Int}(B)$, there are $0<r(a)<\frac 12$ and $\epsilon(a)>0$ such that $B_{2r(a)}(a)\subset \text{Int}(B)$ and such that $|f(x) - x| < \epsilon(a)$ for all $x\in B_{2r(a)}(a)$ implies $B_{r(a)}(a)\subset f(B)$.
Now let's get to the general case (notation as above): Since $A$ is closed, the set $A_m= A \cap \overline{B_m(0)}\setminus B_{m-1}(0)$ is compact for every $m\in \mathbb N$. Hence the covering $\{B_{r(a)}(a)\}_{a\in A_m}$ of $A_m$ contains a finite subcovering $\{B_{r(a)}(a)\}_{a\in F_m} \subset \{B_{r(a)}(a)\}_{a\in A_m}$ ($F_m\subset A_m$ finite). If we let
$$\epsilon_m = \min_{a \in F_m}\, \epsilon(a)$$
then $|f(x) - x| < \epsilon_{m} \; \; \forall \, x\in B \cap \overline{B_{m+1}(0)}\setminus B_{m-2}(0)$ implies $A_m\subset \bigcup_{a\in F_m} B_{r(a)}(a) \subset f(B)$.
So all that is needed now is to find a continuous function $\sigma: B \to (0,\infty)$ which satisfies, for every $m \in \mathbb N$: $$\tag{\ast} \sigma(x) \le \epsilon_m \qquad \forall \, x\in B \cap \overline{B_{m+1}(0)}\setminus B_{m-2}(0)$$ Since this will imply $A_m \subset f(B)$ for all $m\in \mathbb N$, and therefore $A = \bigcup_{m=1}^\infty A_m \subset f(B)$ if $|f(x) - x| < \sigma(x)$. We shall assume (wlog) that $\epsilon_1 \ge \epsilon_2 \ge \epsilon_3 \ge \dots$
$\sigma$ can be constructed in the following way: Let $h:[0,\infty) \to (0,\infty)$ be the continuous (piecewise linear and nonincreasing) function determined by setting $h(m) = \epsilon_{m+2}$ for $m=0,1,2,\dots$ and extending linearly on all intervals $[m,m+1]$. Now set $$\sigma(x) := h(\Vert x\Vert),\quad \text{where }\,\Vert x\Vert = \text{Euclidean norm}$$ The map $\sigma$ is continuous, positive and for $x \in \overline{B_{m+1}(0)}\setminus B_{m-2}(0)$, we have $$\sigma(x) = h(\Vert x\Vert) \le h(m-2) = \epsilon_{m}$$ So $(\ast)$ is satisfied and this concludes the proof.
- | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 1, "x-ck12": 0, "texerror": 0, "math_score": 0.9962539672851562, "perplexity": 56.82504586423364}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-40/segments/1443737940794.79/warc/CC-MAIN-20151001221900-00009-ip-10-137-6-227.ec2.internal.warc.gz"} |
https://de.mathworks.com/help/deeplearning/ug/train-network-with-lstm-projected-layer.html | # Train Network with LSTM Projected Layer
Train a deep learning network with an LSTM projected layer for sequence-to-label classification.
To compress a deep learning network, you can use projected layers. The layer introduces learnable projector matrices $Q$, replaces multiplications of the form $Wx$, where $W$ is a learnable matrix, with the multiplication $WQ{Q}^{\top }x$, and stores $Q$ and $W\prime =WQ$ instead of storing $W$. Projecting $x$ into a lower dimensional space using $Q$ typically requires less memory to store the learnable parameters and can have similarly strong prediction accuracy.
Reducing the number of learnable parameters by projecting an LSTM layer rather than reducing the number of hidden units of the LSTM layer maintains the output size of the layer and, in turn, the sizes of the downstream layers, which can result in better prediction accuracy.
These charts compare the test accuracy and the number of learnable parameters of the LSTM network and the projected LSTM network that you train in this example.
In this example, you train an LSTM network for sequence classification, then train an equivalent network with an LSTM projected layer. You then compare the test accuracy and the number of learnable parameters for each of the networks.
Load the Japanese Vowels data set described in [1] and [2]. `XTrain` is a cell array containing 270 sequences of varying length with 12 features corresponding to LPC cepstrum coefficients. `TTrain` is a categorical vector of labels 1, 2, ..., 9. The entries in `XTrain` are matrices with 12 rows (one row for each feature) and a varying number of columns (one column for each time step).
`[XTrain,TTrain] = japaneseVowelsTrainData;`
Visualize the first time series in a plot. Each line corresponds to a feature.
```figure plot(XTrain{1}') title("Training Observation 1") numFeatures = size(XTrain{1},1); legend("Feature " + string(1:numFeatures),Location="northeastoutside")```
### Define Network Architecture
Define the LSTM network architecture.
• Specify a sequence input layer with an input size matching the number of features of the input data.
• Specify an LSTM layer with 100 hidden units that outputs the last element of the sequence.
• Specify a fully connected layer of a size equal to the number of classes, followed by a softmax layer and a classification layer.
```inputSize = 12; numHiddenUnits = 100; numClasses = 9; layers = [ ... sequenceInputLayer(inputSize) lstmLayer(numHiddenUnits,OutputMode="last") fullyConnectedLayer(numClasses) softmaxLayer classificationLayer];```
### Specify Training Options
Specify the training options.
• Train using the Adam solver.
• Train with a mini-batch size of 27 for 50 epochs.
• Because the mini-batches are small with short sequences, the CPU is better suited for training. Train using the CPU.
• Display the training progress in a plot and suppress the verbose output.
```maxEpochs = 50; miniBatchSize = 27; options = trainingOptions("adam", ... MiniBatchSize=miniBatchSize, ... MaxEpochs=maxEpochs, ... ExecutionEnvironment="cpu", ... Plots="training-progress", ... Verbose=false);```
### Train Network
Train the LSTM network with the specified training options.
`net = trainNetwork(XTrain,TTrain,layers,options);`
### Test Network
Calculate the classification accuracy of the predictions on the test data.
```[XTest,TTest] = japaneseVowelsTestData; YTest = classify(net,XTest,MiniBatchSize=miniBatchSize); acc = sum(YTest == TTest)./numel(TTest)```
```acc = 0.9297 ```
View the number of learnables of the network using the `analyzeNetwork` function.
`analyzeNetwork(net)`
In order to compare the total number of learnable parameters of each network, store the total number of learnable parameters in a variable.
`totalLearnables = 46100;`
### Train Projected LSTM Network
Create an identical network with an LSTM projected layer in place of the LSTM layer.
For the LSTM projected layer:
• Specify the same number of hidden units as the LSTM layer
• Specify an output projector size of 25% of the number of hidden units.
• Specify an input projector size of 75% of the input size.
• Ensure that the output and input projector sizes are positive by taking the maximum of the sizes and 1.
```outputProjectorSize = max(1,floor(0.25*numHiddenUnits)); inputProjectorSize = max(1,floor(0.75*inputSize)); layersProjected = [ ... sequenceInputLayer(inputSize) lstmProjectedLayer(numHiddenUnits,outputProjectorSize,inputProjectorSize,OutputMode="last") fullyConnectedLayer(numClasses) softmaxLayer classificationLayer];```
Train the projected LSTM network with the same data and training options.
`netProjected = trainNetwork(XTrain,TTrain,layersProjected,options);`
### Test Projected Network
Calculate the classification accuracy of the predictions on the test data.
```[XTest,TTest] = japaneseVowelsTestData; YTest = classify(netProjected,XTest,MiniBatchSize=miniBatchSize); accProjected = sum(YTest == TTest)./numel(TTest)```
```accProjected = 0.8784 ```
View the number of learnables of the network using the `analyzeNetwork` function.
`analyzeNetwork(netProjected)`
In order to compare the total number of learnable parameters of each network, store the total number of learnable parameters in a variable.
`totalLearnablesProjected = 17500;`
### Compare Networks
Compare the test accuracy and number of learnables in each network. Depending on the projection sizes, the projected network can have significantly fewer learnable parameters and still maintain strong prediction accuracy.
Create a bar chart showing the test accuracy of each network.
```figure bar([acc accProjected]) xticklabels(["Unprojected","Projected"]) xlabel("Network") ylabel("Test Accuracy") title("Test Accuracy")```
Create a bar chart showing the test accuracy the number of learnables of each network.
```figure bar([totalLearnables totalLearnablesProjected]) xticklabels(["Unprojected","Projected"]) xlabel("Network") ylabel("Number of Learnables") title("Number of Learnables")```
### Bibliography
1. M. Kudo, J. Toyama, and M. Shimbo. "Multidimensional Curve Classification Using Passing-Through Regions." Pattern Recognition Letters. Vol. 20, No. 11–13, pages 1103–1111.
2. UCI Machine Learning Repository: Japanese Vowels Dataset. https://archive.ics.uci.edu/ml/datasets/Japanese+Vowels | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 9, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7968351244926453, "perplexity": 1145.2895223750131}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764500017.27/warc/CC-MAIN-20230202101933-20230202131933-00078.warc.gz"} |
https://socratic.org/questions/how-do-you-solve-3x-2-8-0-graphically | Algebra
Topics
# How do you solve 3x^2-8=0 graphically?
Dec 29, 2017
Graphical approach....
$x \approx \pm 1.63$
#### Explanation:
So an alternative way of solving this is graphically,
The solution to this problem is hence were the function,
$y = 3 {x}^{2} - 8$ and $y = 0$ intersect
So we can now sketch the two functions, we can grpah the line $y = 0$, this is just the $x$ - axis, then sketch the curve, $y = 3 {x}^{2} - 8$, there is a few ways of doing this, one being by plotting many diffiferent points over a particular domain:
We can see by plotting a few points, that where they intersect is
$x \approx \pm 1.63$
This is just a method without using calculator and just graphical approaches.
But the actuall answer is $x = \pm \sqrt{\frac{8}{3}} = \pm \frac{2 \sqrt{6}}{3}$
You can see this in the other answer provided...
##### Impact of this question
151 views around the world | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 8, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9405748248100281, "perplexity": 905.7448251405237}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-35/segments/1566027314852.37/warc/CC-MAIN-20190819160107-20190819182107-00153.warc.gz"} |
https://physics.stackexchange.com/questions/562462/is-spacetime-curved-in-a-near-earth-free-falling-objects-frame-of-reference/562497 | # Is spacetime curved in a near-earth-free-falling-object's frame of reference?
If I float motionless in outer space, I will measure spacetime to be approximately flat. By the equivalence principle, I will get flat spacetime if I am free falling near earth. Is this right? otherwise I can distinguish between the two scenarios.
Let say I declare myself (while free falling) to be at rest in an inertial frame of reference under GR. I see the earth accelerating towards me. What causes that acceleration? It's not the curvature of spacetime, right? I just measured it to be flat.
• – mmesser314 Jun 28 '20 at 20:40
• The first gives an elementary explanation of why time slows near the mass of the Earth. The second explains why this implies space is curved near Earth. – mmesser314 Jun 28 '20 at 20:47
## 6 Answers
If I float motionless in outer space, I will measure spacetime to be approximately flat. By equivalence principle, I will get flat spacetime if I am free falling near earth. Is this right? otherwise I can distinguish between the two scenarios.
Notice that the curvature of spacetime is a tensor, so it is a covariant quantity. In particular, if it is zero in one frame then it is zero in all frames and if it is nonzero in one frame then it is nonzero in all frames.
However, in order to measure spacetime curvature requires a sufficiently large region of spacetime. The equivalence principle only applies if you use a region of spacetime which is too small to measure any curvature. That caveat is very important for understanding the equivalence principle, it only applies locally where “locally” means over a small enough region of spacetime that the spacetime curvature cannot be detected.
Let say I declare myself an inertial frame of reference under GR. I see the earth accelerating towards me. What causes that acceleration? It's not the curvature of spacetime, right? I just measured it to be flat.
The floor accelerates because the ground pushes up on it. There is no gravitational force in this frame so there is no downward force to counteract the upward force. Therefore the floor accelerates.
Similarly, the ground immediately under the floor has two forces on it: a downward force from the floor and an upward force from the earth immediately under the ground. The upward force is larger than the downward force, so it accelerates upward.
This continues with the next layer of earth and the next, and eventually you get far enough away that the curvature becomes detectable over the region and the equivalence principle no longer applies.
The equivalence principle applies only locally. An inertial reference reference frame near the Earth does not extend as far as centre of the Earth (which determines the position of the surface of the Earth). Spacetime is not flat over regions where tidal forces (differences in gravitational motions) can be detected.
Compare this to observing that the surface of the Earth is close to flat in the region of your town. You cannot conclude the flat Earth theory from that observation.
• Suppose I am currently 1m from the earth surface, are you saying if I measure 1 nano meter around me, then I get flat spacetime? but if I measure spacetime at 1 meter away, then I get a massive-earth-curvature (9.8g) in spacetime? – whop Jun 28 '20 at 19:28
• No. The distance you can measure an inertial frame is limited by the detection of tidal forces which are extremely small. You would measure the surface of the Earth as accelerating towards you because it is supported by active forces, not by gravity. – Charles Francis Jun 28 '20 at 19:33
I found this question a very apt one to probe what it is we are saying about gravity in general relativity. My answer will agree with one already posted by Charles Francis, but perhaps I can help by spelling out the analysis in more detail.
I would begin by constructing or imagining a spacetime diagram. Draw on the diagram the worldline of yourself and of planet Earth. Both these worldlines are geodesics. Now measure the separation between the two worldlines, as a function of proper time along both of them. We find that the separation is changing quadratically with time. That quadratic change is the essential ingredient in one way of measuring spacetime curvature: the way called geodesic deviation. The notion of a distance between two geodesics a long way away from one another is rather hard to define, but for geodesics close to one another it can be done in a well-defined way. The essence of the observation is that if this distance is $$\eta$$ then for timelike geodesics and small $$\eta$$ it will obey the equation $$\frac{d^2\eta}{d \tau^2} = K c^2 \eta$$ where $$K$$ is the local Gaussian curvature of spacetime (in a direction singled out by the chosen geodesics). What this means is that if I am sitting in my own little inertial frame of reference, in freefall, and near to me is another thing in free fall, and I notice that the distance between us is changing quadraticaly (not just linearly), then I have detected the presence of spacetime curvature.
Notice that spacetime curvature is well-defined even at a point, but its effects tend to zero in the limit of small times and distance at a rate that is at least quadratic in distance and time. The equivalence principle is based on that observation. The mathematical statement would be to say that the spacetime metric is not merely Minkowskian at any given event P (in suitable coordinates), but also at nearby events, in that its departure from Minkowskian form only appears at quadratic not linear order in the spacetime displacement from P: $$g_{ab} = \eta_{ab} + O(x^a - x^a_P)^2$$
After writing this much, I began to ask myself, "is it really that simple?" Is the Gaussian curvature of spacetime near the surface of the Earth equal to $$-g / c^2 R_E$$? The answer is yes, it is that simple, but a further remark is called-for. The quadratic effect that we considered here, involving timelike geodesics, would be correctly described by Newtonian gravity. So one might argue that we don't need to invoke the concept of curvature to describe them. That is correct: we could just say there is a gravitational force as in Newton's theory. The more interesting case would be to find a departure from Newtonian predictions for worldlines, or to detect the curvature of spacetime in the spatial direction, and that is harder to do. It turns out that it is of a similar size to the one we just calculated. The spacetime curvature in the vertical spatial direction near to the surface of the Earth is equal to $$-g / c^2 R_E$$, and this means that a circle oriented in the vertical direction, such as a bicycle wheel or the London Eye, would have a smaller area than you might expect on the basis of its circumference. It is a small effect though: just 230 nm$$^2$$ missing for the London Eye.
Postscript
The distance $$R_E$$ in the above calculation is equal to the radius of the Earth, not the distance from the surface of the Earth. This is because the surface of the Earth is not in free fall, but the centre of the Earth is. So the two worldlines are that of the person in free fall near Earth and that of the centre of the Earth.
You are saying "If I float motionless in outer space, I will measure spacetime to be approximately flat.". Let's say this is correct in the voids of intergalactic space.
Now when you say "By the equivalence principle, I will get flat spacetime if I am free falling near earth.", this is not correct. Near earth, you are inside Earth's gravitational field, inside the Sun's gravitational field, and inside the Milky Way's gravitational field (etc.). You are in curved spacetime.
Now you are saying "I see the earth accelerating towards me. What causes that acceleration? It's not the curvature of spacetime, right? I just measured it to be flat." In reality, you do measure spacetime to be curved near Earth. This curvature is what causes the acceleration. The reason you are accelerating towards Earth is that curvature is dominated by Earth's stress energy near Earth, but you are still inside the Sun's gravitational field and the Milky Way's gravitational field too (etc.). Curvature in different directions does cancel out and the net effect is what you see that you are accelerating towards Earth.
Just like when you are at the center of the Earth, you do feel weightless. This is because curvature does cancel out from all directions. Does this mean there is no curvature at the center of the Earth? No! Contrary to popular belief, there is curvature at the center of Earth, but you do feel weightless. This is because the radial four acceleration is zero, but curvature is nonzero.
The geometry of spacetime is described by a function called the metric tensor. If you're starting to learn GR then any moment you'll encounter the Schwarzschild metric that describes the geometry outside a sphrically symmetric body. We get the four acceleration using the geodesic equation: $${d^2 x^\mu \over d\tau^2} = - \Gamma^\mu_{\alpha\beta} {dx^\alpha \over d\tau} {dx^\beta \over d\tau}$$ where the $$\Gamma^\mu_{\alpha\beta}$$ are called [Christoffel symbols][5] (of the second kind) and they depend on the spacetime curvature. When $$r = 0$$ the Christoffel symbol $$\Gamma_{tt}^r$$ is zero and that means the radial four-acceleration is zero and that means you're weightless.
The answer to your question is that near Earth, in your case, when you are free falling towards Earth, there is still curvature, and that causes the acceleration.
This can be easily understood in another way, using the four velocity vector. If you accept that the Universe is set up so, that the magnitude of the four velocity vector is always constant. If you are initially stationary near Earth, you are still inside Earth's gravitational field. This causes time dilation, you will slow down in the temporal dimension. Since the four vector's magnitude is constant, your spatial component will need to compensate. You will start moving in space. You will start moving towards the center of gravity. Why will you accelerate? Because you are getting deeper and deeper inside the gravitational field of the Earth, curvature is getting stronger (still outside the surface), and the GR potential is getting stronger. You are moving towards Earth, and you are even more slowing down in the temporal dimension. Your spatial component needs to compensate even more, this you gain more speed, you are accelerating.
Now in your case, it is very important to understand the difference between curvature and potential.
Gravitational acceleration depends on the gravitational force, which is encoded (within a reference frame) in the components of $$\Gamma_{ab}{}^{c}$$ Time dilation effects depend on the gravitational potential, which is encoded, within a reference frame, in the components of $$g_{ab}$$.
Does spacetime curvature (for time dilation) cancel out at the point of center of mass (because curvature effects cancel out from all directions)?
So the answer to your question is, that you are accelerating towards Earth, because there is nonzero curvature, and the net effect causes a radial four acceleration vector to point towards the center of Earth. You are saying that while you are freefalling towards Earth, you are measuring spacetime to be flat, but that is not correct. If you measure spacetime curvature near Earth, inside Earth's gravitational field, you will see it is not flat, the curvature is nonzero, and the potential is nonzero too. If you do this outside Earth's surface, you will get a radial four acceleration that points towards the center of Earth, and that is why you accelerate.
The equivalence principle only applies if you use a region of spacetime which is too small to measure any curvature.
@Dale I am slightly doubtful about the application of this condition. This statement is misused many times. I think if the observer, as well as the space station within which he floats, freely falls towards the earth, he always measures the spacetime to be flat WRT him, and since the space station is freely falling along with him, all the experiments being performed by the observer produce the same results as those performed by an observer floating in an interstellar space away from any gravitational field. That is, whether the length of the space station is $$1\space m$$ or $$1\space Km$$, the spacetime is flat all inside it from the viewpoint of the observer inside the space station.
However, the observer can claim that the earth is mechanically accelerated towards him inside his flat spacetime.
The only thing that may make the observer doubtful about if the spacetime is entirely flat inside the space station is the difference of G-field obeying an inverse-square law, i.e., the gravitational field is not uniform in reality. This causes the nearer parts of the space station to the earth to accelerate with greater values compared to the farther parts. The rigidity of the space station's body makes the entire station accelerate with, say, an average value. This value slightly differs from the acceleration of the observer floating within the station, and thus the observer sees that the space station is accelerating WRT him though this acceleration is very small. On the other hand, the acceleration vectors are convergent towards the center of the plant, which causes tidal forces to be detected inside the space station as mentioned by some contributors here.
Nonetheless, if we can assume a uniform G-field like that near an infinitely large plate (instead of planet, assume that the space station and the observer floating within are both freely falling towards this huge plate, that is), the spacetime is entirely and exactly flat everywhere inside the space station regardless of how large the spatial dimensions of the space station are. Remember that, for such a plate, the G-field, similar to the E-field inside a parallel-plate capacitor, is exactly uniform.
Remember that whether you assume a planet or a massive plate, the observer floating in the freely-falling space station always claims that the spacetime is nearly flat inside the space station, which this flatness never justifies the considerable acceleration of the planet/plate towards the observer unless the observer assumes that the planet/plate is somehow mechanically accelerated towards him. In other words, we are not allowed to say that because there is a very small curvature inside the space station (in the example of the planet), this small curvature explains the acceleration of the planet towards the observer inside the space station. This phenomenon is more perceivable in the example of the huge plate: Can the observer inside the space station attribute the acceleration of the plate to the exactly zero-spacetime curvature inside the space station? The answer is clearly negative.
What causes that acceleration? It's not the curvature of spacetime, right? I just measured it to be flat.
Assume that, away from any gravitational field, an observer and an object are at rest WRT each other inside a flat spacetime. Suddenly, the object accelerates towards this observer. Can we say that the flat spacetime attached to the observer is abruptly bent just because an object is accelerating away from or towards him?
Therefore, I think that the spacetime is bent for the observer standing on the earth as well as for the observer attached to the accelerating object (in my later example), whereas it is flat for the falling observer in the falling space station as well as for the observer floating in an interstellar space just watching an object is accelerated towards him (in my later example).
• said “if the observer, as well as the space station within which he floats, freely falls towards the earth he always measures the spacetime to be flat WRT him”. This is not at all correct, but more importantly that should be in a comment to my answer instead of in an answer to the question – Dale Jun 28 '20 at 22:21
• See Sean Carroll’s lecture notes: arxiv.org/abs/gr-qc/9712019 Particularly the discussion around p 98-100 or so. – Dale Jun 28 '20 at 22:30
• @Dale The answer is edited. – Mohammad Javanshiry Jun 29 '20 at 7:04
If I float [...] in outer space, I will measure spacetime to be approximately flat. [...]
Strictly speaking, you floating all alone by yourself would not quite be capable of determining the curvature (values of curvature invariants) of the region that contains you, along your trajectory. Instead, you'd need the assistance of at least another four distinct and separated participants;
hence Synge's "Five-Point Curvature Meter" (Gen. Rel, p. 409).
And, in order to measure curvature accordingly, you (or any of your four assistants) wouldn't necessarily have to "float freely" (a.k.a. "in free fall"). The measurement of curvature (of a region, point by point) is somewhat separate from the measurement of anyone's "freeness", or acceleration;
cmp. How to express the magnitude of proper acceleration through spacetime intervals
Is spacetime curved in a near-earth-free-falling-object's frame of reference?
The curvature of a region is a quantity to be measured unambiguously; regardless of any particular (and available) choice of frame of reference referred to for this purpose. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 17, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8750506639480591, "perplexity": 314.1322373467696}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-31/segments/1627046154042.23/warc/CC-MAIN-20210731011529-20210731041529-00000.warc.gz"} |
http://mathhelpforum.com/algebra/222295-expression-simplification-print.html | # Expression simplification
• September 26th 2013, 06:21 AM
bobred
Expression simplification
Hi
I have these two expressions
$A+B=D$ and $D=\frac{\text{i}2kA}{\text{i}k-\alpha}$
I need to find $B$, so I substitute $D$ into the first expression. The problem is I don't know how to get it into the form below
$B=A\frac{(\text{i}k+\alpha)}{(\text{i}k-\alpha)}$
Thanks
• September 26th 2013, 07:05 AM
votan
Re: Expression simplification
Quote:
Originally Posted by bobred
Hi
I have these two expressions
$A+B=D$ and $D=\frac{\text{i}2kA}{\text{i}k-\alpha}$
I need to find $B$, so I substitute $D$ into the first expression. The problem is I don't know how to get it into the form below
$B=A\frac{(\text{i}k+\alpha)}{(\text{i}k-\alpha)}$
Thanks
You can't. Think of it this way: A + B = D is B = D - A
• September 26th 2013, 07:57 AM
Shakarri
Re: Expression simplification
$B=A\frac{(\text{i}k+\alpha)}{(\text{i}k-\alpha)}$
From this you get $B(ik-\alpha)=A(ik+\alpha)$
The real numbers on the left have to equal the real numbers on the right and the same goes for imaginary numbers
• September 26th 2013, 08:03 AM
votan
Re: Expression simplification
Quote:
Originally Posted by Shakarri
$B=A\frac{(\text{i}k+\alpha)}{(\text{i}k-\alpha)}$
From this you get $B(ik-\alpha)=A(ik+\alpha)$
The real numbers on the left have to equal the real numbers on the right and the same goes for imaginary numbers
The poster does not say imaginary numbers. When he specifies what his question is about we will be able to handle this properly.
• September 26th 2013, 08:27 AM
bobred
Re: Expression simplification
Hi
I find B by hand easy enough, but Maple gives the expression below and I don't know how
$B=A\frac{(\text{i}k+\alpha)}{(\text{i}k-\alpha)}$
The expressions come from boundary values.
• September 26th 2013, 10:49 AM
Shakarri
Re: Expression simplification
With $A+B=D$ and $D=\frac{\text{i}2kA}{\text{i}k-\alpha}$
You get
$A+B=\frac{\text{i}2kA}{\text{i}k-\alpha}$
$B=\frac{\text{i}2kA}{\text{i}k-\alpha}-A$
Factorize out A
$B=A\times(\frac{\text{i}2k}{\text{i}k-\alpha}-1)$
Get a common denominator and simplify.
• September 26th 2013, 12:01 PM
bobred
Re: Expression simplification
Hi, thanks I have got to the point above its just the next step i'm having trouble with. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 20, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9076904058456421, "perplexity": 727.0983488705974}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-32/segments/1438042991076.30/warc/CC-MAIN-20150728002311-00133-ip-10-236-191-2.ec2.internal.warc.gz"} |
https://www.math.gatech.edu/node/16554 | ## What is and how to compute efficiently the Markovian Joint Spectral Radius?
Series:
Applied and Computational Mathematics Seminar
Monday, April 20, 2015 - 15:05
1 hour (actually 50 minutes)
Location:
Skiles 005
,
L'Aquila, Italy
Organizer:
Given a finite set of matrices F, the Markovian Joint Spectral Radius represents the maximal rate of growth of products of matrices in F when the matrices are multiplied each other following some Markovian law. This quantity is important, for instance, in the study of the so called zero stability of variable stepsize BDF methods for the numerical integration of ordinary differential equations. Recently Kozyakin, based on a work by Dai, showed that, given a set F of N matrices of dimension d and a graph G, which represents the admissible products, it is possibile to compute the Markovian Joint Spectral Radius of the couple (F,G) as the classical Joint Spectral Radius of a new set of N matrices of dimension N*d, which are produced as a particular lifting of the matrices in F. Clearly by this approach the exact evaluation or the simple approximation of the Markovian Joint Spectral Radius becomes a challenge even for reasonably small values of N and d. In this talk we briefly review the theory of the Joint Spectral Radius, and we introduce the Markovian Joint Spectral Radius. Furthermore we address the question whether it is possible to reduce the exact calculation computational complexity of the Markovian Joint Spectral Radius. We show that the problem can be recast as the computation of N polytope norms in dimension d. We conclude the presentation with some numerical examples. This talk is based on a joint work with Nicola Guglielmi from the University of L'Aquila, Italy, and Vladimir Yu. Protasov from the Moscow State University, Russia. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8618919253349304, "perplexity": 357.86098423846386}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-09/segments/1518891814566.44/warc/CC-MAIN-20180223094934-20180223114934-00410.warc.gz"} |
https://www.lessonplanet.com/teachers/atomic-fractions-iii | ## Atomic Fractions-III
For this atomic fractions worksheet, students read about electrons and energy levels. Students find all the possible energies that an electron could lose as it jumped from one energy level to another based on a given diagram. They tabulate the possible energy differences from the lowest to the highest on a number line.
Subjects
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I have really appreciated the connecting links to a variety of sources (i.e. National Geographic) and the teacher-tested lessons have been very helpful for me in planning my units. Thanks Lesson Planet!
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Indianapolis, IN | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8413379192352295, "perplexity": 2205.3829628449575}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-44/segments/1476988721405.66/warc/CC-MAIN-20161020183841-00040-ip-10-171-6-4.ec2.internal.warc.gz"} |
https://en.m.wikipedia.org/wiki/Central_binomial_coefficient | # Central binomial coefficient
Pascal's triangle, rows 0 through 7. The numbers in the central column are the central binomial coefficients.
In mathematics the nth central binomial coefficient is the particular binomial coefficient
${\displaystyle {2n \choose n}={\frac {(2n)!}{(n!)^{2}}}{\text{ for all }}n\geq 0.}$
They are called central since they show up exactly in the middle of the even-numbered rows in Pascal's triangle. The first few central binomial coefficients starting at n = 0 are:
1, 2, 6, 20, 70, 252, 924, 3432, 12870, 48620, ...; (sequence A000984 in the OEIS)
## Properties
The central binomial coefficients have ordinary generating function
${\displaystyle {\frac {1}{\sqrt {1-4x}}}=1+2x+6x^{2}+20x^{3}+70x^{4}+252x^{5}+\cdots }$
and exponential generating function
${\displaystyle \sum _{n=0}^{\infty }{\binom {2n}{n}}{\frac {x^{n}}{n!}}=e^{2x}I_{0}(2x),}$
where I0 is a modified Bessel function of the first kind.[1]
They also satisfy the recurrence
${\displaystyle {\binom {2(n+1)}{n+1}}={\frac {4n+2}{n+1}}\cdot {\binom {2n}{n}}.}$
The Wallis product can be written in asymptotic form for the central binomial coefficient:
${\displaystyle {2n \choose n}\sim {\frac {4^{n}}{\sqrt {\pi n}}}.}$
The latter can also be easily established by means of Stirling's formula. On the other hand, it can also be used as a means to determine the constant ${\displaystyle {\sqrt {2\pi }}}$ in front of the Stirling formula, by comparison.
Simple bounds that immediately follow from ${\displaystyle 4^{n}=(1+1)^{2n}=\sum _{k=0}^{2n}{\binom {2n}{k}}}$ are
${\displaystyle {\frac {4^{n}}{2n+1}}\leq {2n \choose n}\leq 4^{n}{\text{ for all }}n\geq 1}$
Some better bounds are[2]
${\displaystyle {\frac {4^{n}}{\sqrt {4n}}}\leq {2n \choose n}\leq {\frac {4^{n}}{\sqrt {3n+1}}}{\text{ for all }}n\geq 1}$
and, if more accuracy is required,
${\displaystyle {2n \choose n}={\frac {4^{n}}{\sqrt {\pi n}}}\left(1-{\frac {c_{n}}{n}}\right){\text{ where }}{\frac {1}{9}} for all ${\displaystyle n\geq 1.}$ [citation needed]
The only central binomial coefficient that is odd is 1. More specifically, the number of factors of 2 in ${\displaystyle {\binom {2n}{n}}}$ is equal to the number of ones in the binary representation of n.[3]
By the Erdős squarefree conjecture, proven in 1996, no central binomial coefficient with n > 4 is squarefree.
The central binomial coefficient ${\displaystyle {2n \choose n}}$ equals the sum of the squares of the elements in row n of Pascal's triangle.[1]
## Related sequences
The closely related Catalan numbers Cn are given by:
${\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={2n \choose n}-{2n \choose n+1}{\text{ for all }}n\geq 0.}$
A slight generalization of central binomial coefficients is to take them as ${\displaystyle {\frac {\Gamma (2n+1)}{\Gamma (n+1)^{2}}}={\frac {1}{n\mathrm {B} (n+1,n)}}}$ , with appropriate real numbers n, where ${\displaystyle \Gamma (x)}$ is the gamma function and ${\displaystyle \mathrm {B} (x,y)}$ is the beta function.
The powers of two that divide the central binomial coefficients are given by Gould's sequence, whose nth element is the number of odd integers in row n of Pascal's triangle.
## References
1. ^ a b Sloane, N. J. A. (ed.). "Sequence A000984 (Central binomial coefficients)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
2. ^ Kazarinoff, N.D. Geometric inequalities, New York: Random House, 1961
3. ^ Sloane, N. J. A. (ed.). "Sequence A000120". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
• Koshy, Thomas (2008), Catalan Numbers with Applications, Oxford University Press, ISBN 978-0-19533-454-8. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 17, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.821882963180542, "perplexity": 1985.1845010408824}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-51/segments/1544376832259.90/warc/CC-MAIN-20181219110427-20181219132427-00150.warc.gz"} |
http://chemistry.stackexchange.com/questions/3937/tie-breaker-rules-for-iupac-nomenclature-of-organic-compounds | # “Tie-breaker” rules for IUPAC nomenclature of organic compounds
I have three questions:
1. To find the parent chain of a saturated hydrocarbon, we have to find the longest chain and then if we have a choice, we choose the one with the more substituents. But what if we still had a choice? What would we do next?
2. Similarly, for numbering the chain, the last step is to number the chain such that the substituent which comes alphabetically first gets the lower number. But what if we again had a choice? I'm not sure here, but I think we can't possibly have another choice. Can anyone confirm this?
3. If an alkyl substituent is attached to the parent chain by a double or triple bond, how would we name it?
Examples: Here are some examples which demonstrate the above 'tie-breakers'.
For question 1:
The (green + blue) and (green + magenta) chains are the longest and both have two substituents.
The (green + blue) and (green + yellow) chains contain the maximum double bonds and are also the longest. They both have one substituent.
For question 2: As I said, I'm not sure if there can possibly be a 'tie-breaker' here.
For question 3:
The longest chain is the green one. I'm not sure how to name the substituent attached by the double bond.
-
could you atleast name any conflicting molecules for each question, it will also make it a lot easier for us to answer. – Aditya Sriram Jan 16 '13 at 3:12
In question 3 do you mean something like this – Aditya Sriram Jan 16 '13 at 3:14
@AdityaSriram Okay. And for your example: yes, I do mean something like that. – Alraxite Jan 16 '13 at 17:33
## For Question 1
### Example 1
You should select the (green + blue) chain because, no matter which among the blue and yellow you pick, the numbering would not start from the green chain rather the yellow or blue.
Now if you pick the blue chain the substituent ($\ce{methyl}$) would get number 4, whereas if you picked the green chain the substituent($\ce{isopropyl\ or\ methylethyl}$) would get the number 5, so in accordance to the First Point of Difference Rule you should select the green + blue chain.
Also Worth noticing is the fact that no matter which chain you pick, the other chain which becomes the substituent would always get the number 7
So locants (4,7) are better than (5,7). $$\begin{matrix} \ce{Better\ name:& 7(2-Isopropylhexyl)-4-methyl\ heptadecane&\\ Rather\ than:& 5-isopropyl-7(3-Methylhexyl)\ heptadecane&} \end{matrix}$$
### Example 2
In this case according to the above mentioned rule, you should check the position of the double bond, now since there is a double bond already in the green chain at the first position it would get number 1 and the numbering would start from there.
If you choose the green + blue chain the other double bond would get number 5 and for the green + yellow chain the other double bond would get number 6. So you should go for the green + blue chain in this case.
Similar to the previous example no matter which chain you choose the other one always gets the same number that is 5.
So locants (1,5) are better than (1,6) with reference to double bonds. $$\begin{matrix} \ce{Better\ Name:& 5-Ethenyl\ hepta-1,5-diene \\ Rather\ than:& 5-Ethylidene\ hepta-1,6-diene} \end{matrix}$$
## For Question 2
If the chain has to be numbered and two substituents have the same locant the n you see the alphabetical order of the names of the groups/substituents and if they are also the same it only means that they are the same substituent and hence are written together with there locants separated by a (comma),.
For example in you would name the below compound as $\ce{2,4-dichloropentane}$
## For Question 3
### Example 1
The substituent in this example would be named $\ce{ethylidene}$. $$\begin{matrix} \ce{Final\ name:& 5-ethylidene\ nona-1,8-diene} \end{matrix}$$ Similar substituents can be named as
\begin{array}{|c|c|c|c|} \hline \ce{Substituent& Saturated\ form& Name\ of& Name\ of \\ && saturated\ form& substituent \\ \hline R=CH2& R-CH3& Methyl& Methylidene\\ \hline R=CH-CH3& R-CH2-CH3& Ethyl& Ethylidene\\ \hline R-CH=CH2& R-CH2-CH3& Ethyl& Ethenyl\\ \hline R=CH-CH2-CH3& R-CH2-CH2-CH3& Propyl& Propylidene\\} \hline \begin{align} \ce{R=C&-CH3\\ |& \\ C&H3} \end{align}& \begin{array}{rl} \ce{R-C&-CH3\\ |\ &\\ C&H3} \end{array}& \ce{Isopropyl& Isopropylidene}\\ \hline \end{array}
-
Could you tell me your sources? – Alraxite Jan 22 '13 at 12:38
Question 1 , Example 1 and 2 only rely on the First point of difference rule, for question 2, it was trivial. – Aditya Sriram Jan 22 '13 at 16:03
I think in case of #1, you should keep the chain which contains the overall less-complex substituents (which would be green and magenta). Stating it into a rule I guess it would mean comparing the longest substituent of both alternatives.
For question #2, you should chose the numbering that gives an overall lower numbering result, even if you had a choice based on the alphabetically first substituent.
I have no idea for question #3. My instinct tells me that naming that =C-CH3 as a substituent feels wrong and I should choose the shorter chain even if its against the rules. But there's nothing scientific about that.
- | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 1, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9169495105743408, "perplexity": 1510.098636191814}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-52/segments/1418802768050.31/warc/CC-MAIN-20141217075248-00048-ip-10-231-17-201.ec2.internal.warc.gz"} |
http://libros.duhnnae.com/2017/jun9/149870425330-On-a-characterization-of-the-complex-hyperbolic-space-Mathematics-Differential-Geometry.php | On a characterization of the complex hyperbolic space - Mathematics > Differential Geometry
On a characterization of the complex hyperbolic space - Mathematics > Differential Geometry - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.
Abstract: Consider a compact K\-{a}hler manifold $M^m$ with Ricci curvature lower bound$Ric M\geq -2m+1 .$ Assume that its universal cover $% \widetilde{M}$ hasmaximal bottom of spectrum $\lambda 1\widetilde{M}% =m^2.$ Then we prove that$\widetilde{M}$ is isometric to the complex hyperbolic space $\Bbb{CH}^m.$
Autor: Ovidiu Munteanu
Fuente: https://arxiv.org/ | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.995634138584137, "perplexity": 4289.33805705441}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-43/segments/1539583512400.59/warc/CC-MAIN-20181019124748-20181019150248-00025.warc.gz"} |
https://brilliant.org/problems/bi-quadratic-equation-2/ | # Bi-quadratic Equation
Level pending
If the roots of the equation $$x^{4}$$ - 4$$x^{3}$$ + 8$$x^{2}$$ + 9x +11 = 0 are $$\alpha$$, $$\beta$$, $$\gamma$$ and $$\delta$$. Then find the value of $$\alpha^{2}$$ + $$\beta^{2}$$ + $$\gamma^{2}$$ + $$\delta^{2}$$ + $$\alpha \times \beta \times \gamma \times \delta$$.
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https://cerncourier.com/a/cms-benefits-from-higher-boosts-for-improved-search-potential-in-run-2/ | # CMS benefits from higher boosts for improved search potential in Run 2
20 May 2016
With the increase in the centre-of-mass energy provided by the Run 2 LHC collisions, the production cross-sections of many new-physics processes are predicted to rise dramatically compared with Run 1, in contrast to those of the background processes. However, this increase in the cross-section is not the only way to enhance search sensitivities in Run 2. The higher energy leads to particle production that is more highly boosted. The large boosts result in the collimation of the decay products of the boosted object, which therefore overlap in the detector. For example, a Z boson that decays to a quark and an antiquark will normally produce two jets if it has a low boost. The same decay of a highly boosted Z boson will – in contrast – produce a single massive jet, because the decay products of the quark and antiquark will merge. Using jet-substructure observables, such as the jet mass or the so-called N-subjettiness, the search sensitivity for boosted objects like boosted top (t) quarks or W, Z and Higgs bosons can be enhanced.
CMS has retuned and optimised these techniques for Run 2 analyses, implementing the latest ideas and algorithms from the realm of QCD and jet-substructure phenomenology. It has been a collaboration-wide effort to commission these tools for analysis use, relying on experts in jet reconstruction and bottom-quark tagging, and on data-analysis techniques from many groups in CMS. These new algorithms significantly improve the identification efficiency of boosted objects compared with Run 1.
Several Run 2 CMS studies probing the boosted regime have already appeared, using the 2015 data set. While searches for boosted entities are pursued by many CMS analysis groups, the Beyond 2 Generations (B2G) group focuses specifically on final states composed of one or more boosted objects. Signal processes of interest in the B2G group include W´ → tb and diboson (VV/VH/HH) resonances, where W´ represents a new heavy W boson, “V” a W or Z boson, and H a Higgs boson. Other B2G studies focus on searches for pair- or singly produced vector-like quarks T and B through the decays T → Wb and B → tW. The search range for these novel particles generally lies between 700 GeV and 4 TeV, yielding many boosted objects when these particles decay.
Another study in the B2G group is the search for a more massive version (Z´) of the elementary Z boson, decaying to a top-quark pair (Z´ → tt). This search is performed in the semileptonic decay channel, for which the final state consists of a boosted top-quark candidate, a lepton, missing transverse momentum, and a tagged bottom-quark jet. Here, the boosted topology not only affects the reconstruction of the top-quark candidate, but also the lepton, whose isolation can be spoiled by the nearby bottom-quark jet. Again, special identification criteria are implemented to maintain a high signal acceptance. This analysis excludes Z´ masses up to 3.4 (4.0) TeV for signal widths equal to 10% (30%) of the Z´ mass, already eclipsing Run 1 limits. A complementary analysis, in the all-hadronic topology, is now under way – an event display showing two boosted top-quark candidates is shown in the figure. The three-subjet topology seen for each boosted top-quark candidate is as expected for such decays.
With these new boosted-object reconstruction techniques now implemented and commissioned for Run 2, CMS anxiously awaits possible discoveries with the 2016 LHC data set. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8707405924797058, "perplexity": 2569.7472941646674}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323587926.9/warc/CC-MAIN-20211026200738-20211026230738-00448.warc.gz"} |
https://cforall.uwaterloo.ca/trac/changeset/ad1770be8bf86f42ffbb26be74b2ba25f109bce8/doc/proposals/concurrency/concurrency.tex | Ignore:
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May 11, 2017, 11:34:16 AM (4 years ago)
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rf803a75 % math escape $...$ (dollar symbol) \documentclass[twoside,11pt]{article} \documentclass[letterpaper,12pt,titlepage,oneside,final]{book} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \usepackage{graphicx} \usepackage{tabularx} \usepackage{multicol} \usepackage[acronym]{glossaries} \usepackage{varioref} % extended references \usepackage{inconsolata} \usepackage{varioref} \usepackage{listings} % format program code \usepackage[flushmargin]{footmisc} % support label/reference in footnote \newcommand{\cit}{\textsuperscript{[Citation Needed]}\xspace} \newcommand{\code}[1]{\lstinline[language=CFA]{#1}} \newcommand{\pseudo}[1]{\lstinline[language=Pseudo]{#1}} \newcommand{\pscode}[1]{\lstinline[language=pseudo]{#1}} \newcommand{\TODO}{{\Textbf{TODO}}} \input{glossary} % ### # # # # # ####### \section{Introduction} \chapter{Introduction} This proposal provides a minimal core concurrency API that is both simple, efficient and can be reused to build higher-level features. The simplest possible concurrency core is a thread and a lock but this low-level approach is hard to master. An easier approach for users is to support higher-level constructs as the basis of the concurrency in \CFA. Indeed, for highly productive parallel programming, high-level approaches are much more popular~\cite{HPP:Study}. Examples are task based, message passing and implicit threading. % ##### ####### # # ##### ##### # # # # ####### # # ##### # \section{Concurrency} \chapter{Concurrency} Several tool can be used to solve concurrency challenges. Since these challenges always appear with the use of mutable shared-state, some languages and libraries simply disallow mutable shared-state (Erlang~\cite{Erlang}, Haskell~\cite{Haskell}, Akka (Scala)~\cite{Akka}). In these paradigms, interaction among concurrent objects relies on message passing~\cite{Thoth,Harmony,V-Kernel} or other paradigms that closely relate to networking concepts (channels\cit for example). However, in languages that use routine calls as their core abstraction mechanism, these approaches force a clear distinction between concurrent and non-concurrent paradigms (i.e., message passing versus routine call). Which in turn means that, in order to be effective, programmers need to learn two sets of designs patterns. This distinction can be hidden away in library code, but effective use of the librairy still has to take both paradigms into account. Approaches based on shared memory are more closely related to non-concurrent paradigms since they often rely on basic constructs like routine calls and objects. At a lower level these can be implemented as locks and atomic operations. Many such mechanisms have been proposed, including semaphores~\cite{Dijkstra68b} and path expressions~\cite{Campbell74}. However, for productivity reasons it is desireable to have a higher-level construct be the core concurrency paradigm~\cite{HPP:Study}. An approach that is worth mentionning because it is gaining in popularity is transactionnal memory~\cite{Dice10}[Check citation]. While this approach is even pursued by system languages like \CC\cit, the performance and feature set is currently too restrictive to add such a paradigm to a language like C or \CC\cit, which is why it was rejected as the core paradigm for concurrency in \CFA. One of the most natural, elegant, and efficient mechanisms for synchronization and communication, especially for shared memory systems, is the \emph{monitor}. Monitors were first proposed by Brinch Hansen~\cite{Hansen73} and later described and extended by C.A.R.~Hoare~\cite{Hoare74}. Many programming languages---e.g., Concurrent Pascal~\cite{ConcurrentPascal}, Mesa~\cite{Mesa}, Modula~\cite{Modula-2}, Turing~\cite{Turing:old}, Modula-3~\cite{Modula-3}, NeWS~\cite{NeWS}, Emerald~\cite{Emerald}, \uC~\cite{Buhr92a} and Java~\cite{Java}---provide monitors as explicit language constructs. In addition, operating-system kernels and device drivers have a monitor-like structure, although they often use lower-level primitives such as semaphores or locks to simulate monitors. For these reasons, this project proposes monitors as the core concurrency construct. % # # ####### # # ### # ####### # # ##### \subsection{Monitors} \section{Monitors} A monitor is a set of routines that ensure mutual exclusion when accessing shared state. This concept is generally associated with Object-Oriented Languages like Java~\cite{Java} or \uC~\cite{uC++book} but does not strictly require OOP semantics. The only requirements is the ability to declare a handle to a shared object and a set of routines that act on it : \begin{lstlisting} \begin{cfacode} typedef /*some monitor type*/ monitor; int f(monitor & m); f(m); } \end{lstlisting} \end{cfacode} % ##### # # # % ##### # # ####### ####### \subsubsection{Call semantics} \label{call} \subsection{Call semantics} \label{call} The above monitor example displays some of the intrinsic characteristics. Indeed, it is necessary to use pass-by-reference over pass-by-value for monitor routines. This semantics is important because at their core, monitors are implicit mutual-exclusion objects (locks), and these objects cannot be copied. Therefore, monitors are implicitly non-copyable. Another aspect to consider is when a monitor acquires its mutual exclusion. For example, a monitor may need to be passed through multiple helper routines that do not acquire the monitor mutual-exclusion on entry. Pass through can be both generic helper routines (\code{swap}, \code{sort}, etc.) or specific helper routines like the following to implement an atomic counter : \begin{lstlisting} mutex struct counter_t { /*...see section §\ref{data}§...*/ }; \begin{cfacode} monitor counter_t { /*...see section $\ref{data}$...*/ }; void ?{}(counter_t & nomutex this); //constructor //need for mutex is platform dependent here void ?{}(size_t * this, counter_t & mutex cnt); //conversion \end{lstlisting} \end{cfacode} Here, the constructor(\code{?\{\}}) uses the \code{nomutex} keyword to signify that it does not acquire the monitor mutual exclusion when constructing. This semantics is because an object not yet constructed should never be shared and therefore does not require mutual exclusion. The prefix increment operator uses \code{mutex} to protect the incrementing process from race conditions. Finally, there is a conversion operator from \code{counter_t} to \code{size_t}. This conversion may or may not require the \code{mutex} key word depending on whether or not reading an \code{size_t} is an atomic operation or not. Having both \code{mutex} and \code{nomutex} keywords could be argued to be redundant based on the meaning of a routine having neither of these keywords. For example, given a routine without quualifiers \code{void foo(counter_t & this)} then one could argue that it should default to the safest option \code{mutex}. On the other hand, the option of having routine \code{void foo(counter_t & this)} mean \code{nomutex} is unsafe by default and may easily cause subtle errors. It can be argued that \code{nomutex} is the more "normal" behaviour, the \code{nomutex} keyword effectively stating explicitly that "this routine has nothing special". Another alternative is to make having exactly one of these keywords mandatory, which would provide the same semantics but without the ambiguity of supporting routine \code{void foo(counter_t & this)}. Mandatory keywords would also have the added benefice of being self-documented but at the cost of extra typing. In the end, which solution should be picked is still up for debate. For the reminder of this proposal, the explicit approach is used for clarity. The next semantic decision is to establish when mutex/nomutex may be used as a type qualifier. Consider the following declarations: \begin{lstlisting} Having both \code{mutex} and \code{nomutex} keywords could be argued to be redundant based on the meaning of a routine having neither of these keywords. For example, given a routine without quualifiers \code{void foo(counter_t & this)} then one could argue that it should default to the safest option \code{mutex}. On the other hand, the option of having routine \code{void foo(counter_t & this)} mean \code{nomutex} is unsafe by default and may easily cause subtle errors. It can be argued that \code{nomutex} is the more "normal" behaviour, the \code{nomutex} keyword effectively stating explicitly that "this routine has nothing special". Another alternative is to make having exactly one of these keywords mandatory, which would provide the same semantics but without the ambiguity of supporting routine \code{void foo(counter_t & this)}. Mandatory keywords would also have the added benefice of being self-documented but at the cost of extra typing. However, since \CFA relies heavily on traits as an abstraction mechanism, the distinction between a type that is a monitor and a type that looks like a monitor can become blurred. For this reason, \CFA only has the \code{mutex} keyword. The next semantic decision is to establish when \code{mutex} may be used as a type qualifier. Consider the following declarations: \begin{cfacode} int f1(monitor & mutex m); int f2(const monitor & mutex m); int f4(monitor *[] mutex m); int f5(graph(monitor*) & mutex m); \end{lstlisting} The problem is to indentify which object(s) should be acquired. Furthermore, each object needs to be acquired only once. In the case of simple routines like \code{f1} and \code{f2} it is easy to identify an exhaustive list of objects to acquire on entry. Adding indirections (\code{f3}) still allows the compiler and programmer to indentify which object is acquired. However, adding in arrays (\code{f4}) makes it much harder. Array lengths are not necessarily known in C and even then making sure we only acquire objects once becomes also none trivial. This can be extended to absurd limits like \code{f5}, which uses a graph of monitors. To keep everyone as sane as possible~\cite{Chicken}, this projects imposes the requirement that a routine may only acquire one monitor per parameter and it must be the type of the parameter (ignoring potential qualifiers and indirections). Also note that while routine \code{f3} can be supported, meaning that monitor \code{**m} is be acquired, passing an array to this routine would be type safe and yet result in undefined behavior because only the first element of the array is acquired. However, this ambiguity is part of the C type system with respects to arrays. For this reason, it would also be reasonnable to disallow mutex in the context where arrays may be passed. \end{cfacode} The problem is to indentify which object(s) should be acquired. Furthermore, each object needs to be acquired only once. In the case of simple routines like \code{f1} and \code{f2} it is easy to identify an exhaustive list of objects to acquire on entry. Adding indirections (\code{f3}) still allows the compiler and programmer to indentify which object is acquired. However, adding in arrays (\code{f4}) makes it much harder. Array lengths are not necessarily known in C and even then making sure we only acquire objects once becomes also none trivial. This can be extended to absurd limits like \code{f5}, which uses a graph of monitors. To keep everyone as sane as possible~\cite{Chicken}, this projects imposes the requirement that a routine may only acquire one monitor per parameter and it must be the type of the parameter with one level of indirection (ignoring potential qualifiers). Also note that while routine \code{f3} can be supported, meaning that monitor \code{**m} is be acquired, passing an array to this routine would be type safe and yet result in undefined behavior because only the first element of the array is acquired. However, this ambiguity is part of the C type system with respects to arrays. For this reason, \code{mutex} is disallowed in the context where arrays may be passed. Finally, for convenience, monitors support multiple acquireing, that is acquireing a monitor while already holding it does not cause a deadlock. It simply increments an internal counter which is then used to release the monitor after the number of acquires and releases match up. % ###### # ####### # % ###### # # # # # \subsubsection{Data semantics} \label{data} \subsection{Data semantics} \label{data} Once the call semantics are established, the next step is to establish data semantics. Indeed, until now a monitor is used simply as a generic handle but in most cases monitors contian shared data. This data should be intrinsic to the monitor declaration to prevent any accidental use of data without its appropriate protection. For example, here is a complete version of the counter showed in section \ref{call}: \begin{lstlisting} mutex struct counter_t { \begin{cfacode} monitor counter_t { int value; }; void ?{}(counter_t & nomutex this) { void ?{}(counter_t & this) { this.cnt = 0; } *this = (int)cnt; } \end{lstlisting} \end{cfacode} This simple counter is used as follows: \begin{center} \begin{tabular}{c @{\hskip 0.35in} c @{\hskip 0.35in} c} \begin{lstlisting} \begin{cfacode} //shared counter counter_t cnt; ... thread N : cnt++; \end{lstlisting} \end{cfacode} \end{tabular} \end{center} Notice how the counter is used without any explicit synchronisation and yet supports thread-safe semantics for both reading and writting. Unlike object-oriented monitors, where calling a mutex member \emph{implicitly} acquires mutual-exclusion, \CFA uses an explicit mechanism to acquire mutual-exclusion. A consequence of this approach is that it extends to multi-monitor calls. \begin{lstlisting} \begin{cfacode} int f(MonitorA & mutex a, MonitorB & mutex b); MonitorB b; f(a,b); \end{lstlisting} \end{cfacode} This code acquires both locks before entering the critical section, called \emph{\gls{group-acquire}}. In practice, writing multi-locking routines that do not lead to deadlocks is tricky. Having language support for such a feature is therefore a significant asset for \CFA. In the case presented above, \CFA guarantees that the order of aquisition is consistent across calls to routines using the same monitors as arguments. However, since \CFA monitors use multi-acquisition locks, users can effectively force the acquiring order. For example, notice which routines use \code{mutex}/\code{nomutex} and how this affects aquiring order : \begin{lstlisting} \begin{cfacode} void foo(A & mutex a, B & mutex b) { //acquire a & b //... } void bar(A & mutex a, B & nomutex b) { //acquire a void bar(A & mutex a, B & /*nomutex*/ b) { //acquire a //... foo(a, b); //acquire b } void baz(A & nomutex a, B & mutex b) { //acquire b void baz(A & /*nomutex*/ a, B & mutex b) { //acquire b //... foo(a, b); //acquire a //... } \end{lstlisting} The multi-acquisition monitor lock allows a monitor lock to be acquired by both \code{bar} or \code{baz} and acquired again in \code{foo}. In the calls to \code{bar} and \code{baz} the monitors are acquired in opposite order. such use leads to nested monitor call problems~\cite{Lister77}, which is a specific implementation of the lock acquiring order problem. In the example above, the user uses implicit ordering in the case of function \code{foo} but explicit ordering in the case of \code{bar} and \code{baz}. This subtle mistake means that calling these routines concurrently may lead to deadlock and is therefore undefined behavior. As shown on several occasion\cit, solving this problem requires : \end{cfacode} The multi-acquisition monitor lock allows a monitor lock to be acquired by both \code{bar} or \code{baz} and acquired again in \code{foo}. In the calls to \code{bar} and \code{baz} the monitors are acquired in opposite order. such use leads to nested monitor call problems~\cite{Lister77}, which is a more specific variation of the lock acquiring order problem. In the example above, the user uses implicit ordering in the case of function \code{foo} but explicit ordering in the case of \code{bar} and \code{baz}. This subtle mistake means that calling these routines concurrently may lead to deadlock and is therefore undefined behavior. As shown on several occasion\cit, solving this problem requires : \begin{enumerate} \item Dynamically tracking of the monitor-call order. % # ####### ####### # # # ####### # # # # \subsubsection{Implementation Details: Interaction with polymorphism} \subsection{Implementation Details: Interaction with polymorphism} At first glance, interaction between monitors and \CFA's concept of polymorphism seems complex to support. However, it is shown that entry-point locking can solve most of the issues. \CFA & pseudo-code & pseudo-code \\ \hline \begin{lstlisting} void foo(monitor & mutex a) { \begin{cfacode}[tabsize=3] void foo(monitor& mutex a){ } \end{lstlisting} &\begin{lstlisting} \end{cfacode} & \begin{pseudo}[tabsize=3] foo(& a) { release(a); } \end{lstlisting} &\begin{lstlisting} \end{pseudo} & \begin{pseudo}[tabsize=3] foo(& a) { //called routine } \end{lstlisting} \end{pseudo} \end{tabular} \end{center} First of all, interaction between \code{otype} polymorphism and monitors is impossible since monitors do not support copying. Therefore, the main question is how to support \code{dtype} polymorphism. Since a monitor's main purpose is to ensure mutual exclusion when accessing shared data, this implies that mutual exclusion is only required for routines that do in fact access shared data. However, since \code{dtype} polymorphism always handles incomplete types (by definition), no \code{dtype} polymorphic routine can access shared data since the data requires knowledge about the type. Therefore, the only concern when combining \code{dtype} polymorphism and monitors is to protect access to routines. \Gls{callsite-locking} would require a significant amount of work, since any \code{dtype} routine may have to obtain some lock before calling a routine, depending on whether or not the type passed is a monitor. However, with \gls{entry-point-locking} calling a monitor routine becomes exactly the same as calling it from anywhere else. First of all, interaction between \code{otype} polymorphism and monitors is impossible since monitors do not support copying. Therefore, the main question is how to support \code{dtype} polymorphism. Since a monitor's main purpose is to ensure mutual exclusion when accessing shared data, this implies that mutual exclusion is only required for routines that do in fact access shared data. However, since \code{dtype} polymorphism always handles incomplete types (by definition), no \code{dtype} polymorphic routine can access shared data since the data requires knowledge about the type. Therefore, the only concern when combining \code{dtype} polymorphism and monitors is to protect access to routines. \Gls{callsite-locking} would require a significant amount of work, since any \code{dtype} routine may have to obtain some lock before calling a routine, depending on whether or not the type passed is a monitor. However, with \gls{entry-point-locking} calling a monitor routine becomes exactly the same as calling it from anywhere else. Note that the \code{mutex} keyword relies on the resolver, which mean that in cases where generic monitor routines is actually desired, writing mutex routine is possible with the proper trait. % ### # # # ### ##### ##### # # ####### ###### \subsection{Internal scheduling} \label{insched} \begin{center} \begin{tabular}{ c @{\hskip 0.65in} c } \begin{lstlisting}[language=Pseudo] \section{Internal scheduling} \label{insched} In addition to mutual exclusion, the monitors at the core of \CFA's concurrency can also be used to achieve synchronisation. With monitors, this is generally achieved with internal or external scheduling as in\cit. Since internal scheduling of single monitors is mostly a solved problem, this proposal concentraits on extending internal scheduling to multiple monitors at once. Indeed, like the \gls{group-acquire} semantics, internal scheduling extends to multiple monitors at once in a way that is natural to the user but requires additional complexity on the implementation side. First, Here is a simple example of such a technique : \begin{cfacode} monitor A { condition e; } void foo(A & mutex a) { // ... // We need someone else to do something now wait(a.e); // ... } void bar(A & mutex a) { // Do the thing foo is waiting on // ... // Signal foo it's done signal(a.e); } \end{cfacode} Note that in \CFA, \code{condition} have no particular need to be stored inside a monitor, beyond any software engineering reasons. Here routine \code{foo} waits for the \code{signal} from \code{bar} before making further progress, effectively ensuring a basic ordering. An important aspect to take into account here is that \CFA does not allow barging, which means that once function \code{bar} releases the monitor, foo is guaranteed to resume immediately after (unless some other function waited on the same condition). This guarantees offers the benefit of not having to loop arount waits in order to guarantee that a condition is still met. The main reason \CFA offers this guarantee is that users can easily introduce barging if it becomes a necessity but adding a barging prevention or barging avoidance is more involved without language support. Supporting barging prevention as well as extending internal scheduling to multiple monitors is the main source of complexity in the design of \CFA concurrency. \subsection{Internal Scheduling - multi monitor} It easier to understand the problem of multi monitor scheduling using a series of pseudo code though experiment. Note that in the following snippets of pseudo-code waiting and signalling is done without the use of a condition variable. While \CFA requires condition variables to use signalling, the variable itself only really holds the data needed for the implementation of internal schedulling. Some languages like JAVA\cit simply define an implicit condition variable for every monitor while other languages like \uC use explicit condition variables. Since the following pseudo-codes are simple and focused experiments, all condition variables are implicit. \begin{multicols}{2} \begin{pseudo} acquire A wait A release A \end{lstlisting}&\begin{lstlisting}[language=Pseudo] \end{pseudo} \columnbreak \begin{pseudo} acquire A signal A release A \end{lstlisting} \end{tabular} \end{center} Easy : like uC++ \begin{center} \begin{tabular}{ c @{\hskip 0.65in} c } \begin{lstlisting}[language=Pseudo] \end{pseudo} \end{multicols} The previous example shows the simple case of having two threads (one for each column) and a single monitor A. One thread acquires before waiting and the other acquires before signalling. There are a few important things to note here. First, both \code{wait} and \code{signal} must be called with the proper monitor(s) already acquired. This can be hidden on the user side but is a logical requirement for barging prevention. Secondly, as stated above, while it is argued that not all problems regarding single monitors are solved, this paper only regards challenges of \gls{group-acquire} and considers other problems related to monitors as solved. An important note about this example is that signalling a monitor is a delayed operation. The ownership of the monitor is transferred only when the monitor would have otherwise been released, not at the point of the \code{signal} statement. A direct extension of the previous example is the \gls{group-acquire} version : \begin{multicols}{2} \begin{pseudo} acquire A & B wait A & B release A & B \end{pseudo} \columnbreak \begin{pseudo} acquire A & B signal A & B release A & B \end{pseudo} \end{multicols} This version uses \gls{group-acquire} (denoted using the \& symbol), but the presence of multiple monitors does not add a particularly new meaning. Synchronization will happen between the two threads in exactly the same way and order. The only difference is that mutual exclusion will cover more monitors. On the implementation side, handling multiple monitors at once does add a degree of complexity but it is not significant compared to the next few examples. For the sake of completeness, here is another example of the single-monitor case, this time with nesting. \begin{multicols}{2} \begin{pseudo} acquire A acquire B release B release A \end{lstlisting}&\begin{lstlisting}[language=Pseudo] acquire A acquire B signal B release B release A \end{lstlisting} \end{tabular} \end{center} Also easy : like uC++ \begin{center} \begin{tabular}{ c @{\hskip 0.65in} c } \begin{lstlisting}[language=Pseudo] acquire A & B wait A & B release A & B \end{lstlisting}&\begin{lstlisting}[language=Pseudo] acquire A & B signal A & B release A & B \end{lstlisting} \end{tabular} \end{center} Simplest extension : can be made like uC++ by tying B to A \begin{center} \begin{tabular}{ c @{\hskip 0.65in} c } \begin{lstlisting}[language=Pseudo] \end{pseudo} \columnbreak \begin{pseudo} acquire B signal B release B \end{pseudo} \end{multicols} While these cases can cause some deadlock issues, we consider that these issues are only a symptom of the fact that locks, and by extension monitors, are not perfectly composable. However, for monitors as for locks, it is possible to write program that using nesting without encountering any problems if they are nested carefully. The next example is where \gls{group-acquire} adds a significant layer of complexity to the internal signalling semantics. \begin{multicols}{2} \begin{pseudo} acquire A // Code Section 1 acquire B acquire A & B // Code Section 2 wait A & B // Code Section 3 release B release A & B // Code Section 4 release A \end{lstlisting}&\begin{lstlisting}[language=Pseudo] \end{pseudo} \columnbreak \begin{pseudo} acquire A // Code Section 5 acquire B acquire A & B // Code Section 6 signal A & B // Code Section 7 release B release A & B // Code Section 8 release A \end{lstlisting} \end{tabular} \end{center} Hard extension : Incorrect options for the signal : \begin{description} \item[-] Release B and baton pass after Code Section 8 : Passing b without having it \item[-] Keep B during Code Section 8 : Can lead to deadlocks since we secretly keep a lock longer than specified by the user \item[-] Instead of release B transfer A and B to waiter then try to reacquire A before running Code Section 8 : This allows barging \end{description} Since we don't want barging we need to pass A \& B and somehow block and get A back. \begin{center} \begin{tabular}{ c @{\hskip 0.65in} c } \begin{lstlisting}[language=Pseudo] \end{pseudo} \end{multicols} It is particularly important to pay attention to code sections 8 and 3 which are where the existing semantics of internal scheduling are undefined. The root of the problem is that \gls{group-acquire} is used in a context where one of the monitors is already acquired. As mentionned in previous sections, monitors support multiple acquiring which means the that nesting \gls{group-acquire} can be done safely. However, in the context of internal scheduling it is important to define the behaviour of the previous pseudo-code. When the signaller thread reaches the location where it should "release A \& B", it actually only needs to release the monitor B. Since the other thread is waiting on monitor B, the signaller thread cannot simply release the monitor into the wild. This would mean that the waiting thread would have to reacquire the monitor and would therefore open the door to barging threads. Since the signalling thread still needs the monitor A, simply transferring ownership to the waiting thread is not an option because it would pottentially violate mutual exclusion. We are therefore left with three options : \subsubsection{Delaying signals} The first more obvious solution to solve the problem of multi-monitor scheduling is to keep ownership of all locks until the last lock is ready to be transferred. It can be argued that that moment is the correct time to transfer ownership when the last lock is no longer needed is what fits most closely to the behaviour of single monitor scheduling. However, this solution can become much more complicated depending on the content of the code section 8. Indeed, nothing prevents a user from signalling monitor A on a different condition variable. In that case, if monitor B is transferred with monitor A, then it means the system needs to handle threads having ownership on more monitors than expected and how to tie monitors together. On the other hand if the signalling thread only transfers monitor A then somehow both monitors A and B have to be transferred to the waiting thread from two different threads. While this solution may work, it was not fully explored because there is no apparent upper bound on the complexity of ownership transfer. \subsubsection{Dependency graphs} In the previous pseudo-code, there is a solution which would statisfy both barging prevention and mutual exclusion. If ownership of both monitors is transferred to the waiter when the signaller releases A and then the waiter transfers back ownership of A when it releases it then the problem is solved. This is the second solution. The problem it encounters is that it effectively boils down to resolving a dependency graph of ownership requirements. Here even the simplest of code snippets requires two transfers and it seems to increase in a manner closer to polynomial. For example the following code which is just a direct extension to three monitors requires at least three ownership transfer and has multiple solutions. \begin{multicols}{2} \begin{pseudo} acquire A acquire B acquire C wait A & B & C 1: release C 2: release B 3: release A \end{lstlisting}&\begin{lstlisting}[language=Pseudo] release C release B release A \end{pseudo} \columnbreak \begin{pseudo} acquire A acquire B acquire C signal A & B & C 4: release C 5: release B 6: release A \end{lstlisting} \end{tabular} \end{center} To prevent barging : \begin{description} \item[-] When the signaller hits 4 : pass A, B, C to waiter \item[-] When the waiter hits 2 : pass A, B to signaller \item[-] When the signaller hits 5 : pass A to waiter \end{description} \begin{center} \begin{tabular}{ c @{\hskip 0.65in} c } \begin{lstlisting}[language=Pseudo] release C release B release A \end{pseudo} \end{multicols} \subsubsection{Partial signalling} Finally, the solution that was chosen for \CFA is to use partial signalling. Consider the following case : \begin{multicols}{2} \begin{pseudo}[numbers=left] acquire A acquire C acquire B wait A & B & C 1: release B 2: release C 3: release A \end{lstlisting}&\begin{lstlisting}[language=Pseudo] acquire B acquire A acquire C signal A & B & C 4: release C 5: release A 6: release B \end{lstlisting} \end{tabular} \end{center} To prevent barging : When the signaller hits 4 : pass A, B, C to waiter. When the waiter hits 1 it must release B, \begin{description} \item[-] \item[-] When the waiter hits 1 : pass A, B to signaller \item[-] When the signaller hits 5 : pass A, B to waiter \item[-] When the waiter hits 2 : pass A to signaller \end{description} acquire A & B wait A & B release A & B release A \end{pseudo} \columnbreak \begin{pseudo}[numbers=left, firstnumber=6] acquire A acquire A & B signal A & B release A & B // ... More code release A \end{pseudo} \end{multicols} The partial signalling solution transfers ownership of monitor B at lines 10 but does not wake the waiting thread since it is still using monitor A. Only when it reaches line 11 does it actually wakeup the waiting thread. This solution has the benefit that complexity is encapsulated in to only two actions, passing monitors to the next owner when they should be release and conditionnaly waking threads if all conditions are met. Contrary to the other solutions, this solution quickly hits an upper bound on complexity of implementation. % Hard extension : % Incorrect options for the signal : % \begin{description} % \item[-] Release B and baton pass after Code Section 8 : Passing b without having it % \item[-] Keep B during Code Section 8 : Can lead to deadlocks since we secretly keep a lock longer than specified by the user % \item[-] Instead of release B transfer A and B to waiter then try to reacquire A before running Code Section 8 : This allows barging % \end{description} % Since we don't want barging we need to pass A \& B and somehow block and get A back. % \begin{center} % \begin{tabular}{ c @{\hskip 0.65in} c } % \begin{lstlisting}[language=Pseudo] % acquire A % acquire B % acquire C % wait A & B & C % 1: release C % 2: release B % 3: release A % \end{lstlisting}&\begin{lstlisting}[language=Pseudo] % acquire A % acquire B % acquire C % signal A & B & C % 4: release C % 5: release B % 6: release A % \end{lstlisting} % \end{tabular} % \end{center} % To prevent barging : % \begin{description} % \item[-] When the signaller hits 4 : pass A, B, C to waiter % \item[-] When the waiter hits 2 : pass A, B to signaller % \item[-] When the signaller hits 5 : pass A to waiter % \end{description} % \begin{center} % \begin{tabular}{ c @{\hskip 0.65in} c } % \begin{lstlisting}[language=Pseudo] % acquire A % acquire C % acquire B % wait A & B & C % 1: release B % 2: release C % 3: release A % \end{lstlisting}&\begin{lstlisting}[language=Pseudo] % acquire B % acquire A % acquire C % signal A & B & C % 4: release C % 5: release A % 6: release B % \end{lstlisting} % \end{tabular} % \end{center} % To prevent barging : When the signaller hits 4 : pass A, B, C to waiter. When the waiter hits 1 it must release B, % \begin{description} % \item[-] % \item[-] When the waiter hits 1 : pass A, B to signaller % \item[-] When the signaller hits 5 : pass A, B to waiter % \item[-] When the waiter hits 2 : pass A to signaller % \end{description} % Monitors also need to schedule waiting threads internally as a mean of synchronization. Internal scheduling is one of the simple examples of such a feature. It allows users to declare condition variables and have threads wait and signaled from them. Here is a simple example of such a technique : % # # # # ### # # # # # # # # # % ####### # # # ### ##### ##### # # ####### ###### \newpage \subsection{External scheduling} \label{extsched} \section{External scheduling} \label{extsched} An alternative to internal scheduling is to use external scheduling instead. This method is more constrained and explicit which may help users tone down the undeterministic nature of concurrency. Indeed, as the following examples demonstrates, external scheduling allows users to wait for events from other threads without the concern of unrelated events occuring. External scheduling can generally be done either in terms of control flow (ex: \uC) or in terms of data (ex: Go). Of course, both of these paradigms have their own strenghts and weaknesses but for this project control flow semantics where chosen to stay consistent with the rest of the languages semantics. Two challenges specific to \CFA arise when trying to add external scheduling with loose object definitions and multi-monitor routines. The following example shows a simple use \code{accept} versus \code{wait}/\code{signal} and its advantages. % ####### ####### ####### ##### ####### ####### ###### ##### ##### \subsubsection{Loose object definitions} \subsection{Loose object definitions} In \uC, monitor declarations include an exhaustive list of monitor operations. Since \CFA is not object oriented it becomes both more difficult to implement but also less clear for the user : \end{center} For the \pseudo{monitor is free} condition it is easy to implement a check that can evaluate the condition in a few instruction. However, a fast check for \pseudo{monitor accepts me} is much harder to implement depending on the constraints put on the monitors. Indeed, monitors are often expressed as an entry queue and some acceptor queue as in the following figure : For the \pscode{monitor is free} condition it is easy to implement a check that can evaluate the condition in a few instruction. However, a fast check for \pscode{monitor accepts me} is much harder to implement depending on the constraints put on the monitors. Indeed, monitors are often expressed as an entry queue and some acceptor queue as in the following figure : \begin{center} % # # ##### ####### # ### # # ####### # # \subsubsection{Multi-monitor scheduling} \subsection{Multi-monitor scheduling} External scheduling, like internal scheduling, becomes orders of magnitude more complex when we start introducing multi-monitor syntax. Even in the simplest possible case some new semantics need to be established : \subsubsection{Implementation Details: External scheduling queues} \subsection{Implementation Details: External scheduling queues} To support multi-monitor external scheduling means that some kind of entry-queues must be used that is aware of both monitors. However, acceptable routines must be aware of the entry queues which means they must be stored inside at least one of the monitors that will be acquired. This in turn adds the requirement a systematic algorithm of disambiguating which queue is relavant regardless of user ordering. The proposed algorithm is to fall back on monitors lock ordering and specify that the monitor that is acquired first is the lock with the relevant entry queue. This assumes that the lock acquiring order is static for the lifetime of all concerned objects but that is a reasonnable constraint. This algorithm choice has two consequences, the entry queue of the highest priority monitor is no longer a true FIFO queue and the queue of the lowest priority monitor is both required and probably unused. The queue can no longer be a FIFO queue because instead of simply containing the waiting threads in order arrival, they also contain the second mutex. Therefore, another thread with the same highest priority monitor but a different lowest priority monitor may arrive first but enter the critical section after a thread with the correct pairing. Secondly, since it may not be known at compile time which monitor will be the lowest priority monitor, every monitor needs to have the correct queues even though it is probable that half the multi-monitor queues will go unused for the entire duration of the program. \subsection{Other concurrency tools} \section{Other concurrency tools} TO BE CONTINUED... \newpage % ###### # ###### # # # ####### # ### ##### # # % # # # # # # # # # # # # # # # ## ## % # # # # # # # # # # # # # # # # % # # # # # # # ####### ####### ####### ####### ### ##### # # \section{Parallelism} \chapter{Parallelism} Historically, computer performance was about processor speeds and instructions count. However, with heat dissipation being a direct consequence of speed increase, parallelism has become the new source for increased performance~\cite{Sutter05, Sutter05b}. In this decade, it is not longer reasonnable to create a high-performance application without caring about parallelism. Indeed, parallelism is an important aspect of performance and more specifically throughput and hardware utilization. The lowest-level approach of parallelism is to use \glspl{kthread} in combination with semantics like \code{fork}, \code{join}, etc. However, since these have significant costs and limitations, \glspl{kthread} are now mostly used as an implementation tool rather than a user oriented one. There are several alternatives to solve these issues that all have strengths and weaknesses. While there are many variations of the presented paradigms, most of these variations do not actually change the guarantees or the semantics, they simply move costs in order to achieve better performance for certain workloads. \section{Paradigm} \subsection{User-level threads} A direct improvement on the \gls{kthread} approach is to use \glspl{uthread}. These threads offer most of the same features that the operating system already provide but can be used on a much larger scale. This approach is the most powerfull solution as it allows all the features of multi-threading, while removing several of the more expensives costs of using kernel threads. The down side is that almost none of the low-level threading problems are hidden, users still have to think about data races, deadlocks and synchronization issues. These issues can be somewhat alleviated by a concurrency toolkit with strong garantees but the parallelism toolkit offers very little to reduce complexity in itself. Examples of languages that support \glspl{uthread} are Erlang~\cite{Erlang} and \uC~\cite{uC++book}. \subsubsection{Fibers : user-level threads without preemption} \subsection{Fibers : user-level threads without preemption} A popular varient of \glspl{uthread} is what is often reffered to as \glspl{fiber}. However, \glspl{fiber} do not present meaningful semantical differences with \glspl{uthread}. Advocates of \glspl{fiber} list their high performance and ease of implementation as majors strenghts of \glspl{fiber} but the performance difference between \glspl{uthread} and \glspl{fiber} is controversial and the ease of implementation, while true, is a weak argument in the context of language design. Therefore this proposal largely ignore fibers. % # # # # % # # ####### ####### \section{Putting it all together} \chapter{Putting it all together} \chapter{Conclusion} % # # # # # # # # # % # ##### # ##### # # ###### \section{Future work} \chapter{Future work} Concurrency and parallelism is still a very active field that strongly benefits from hardware advances. As such certain features that aren't necessarily mature enough in their current state could become relevant in the lifetime of \CFA. \subsection{Transactions} | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6258952021598816, "perplexity": 6053.412000675897}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323585522.78/warc/CC-MAIN-20211022212051-20211023002051-00635.warc.gz"} |
https://dsp.stackexchange.com/questions/43698/what-does-it-mean-when-cross-correlation-between-two-images-occur-at-negative-co/43704 | # What does it mean when cross correlation between two images occur at negative coordinates
I am using Matlab normxcorr2 to calculate the cross correlation between several images, something like what has been done here: in Matlab documentation. There are some of the examples that I get negative values for xoffSet and yoffSet, but I am not sure what it means when these values are negative. Another issue, is practical since I need to give these xoffSet and yoffSet values as an input to coordinates of rectangle in an image, but since these are negative, the function throws an error. I googled it but no success in finding something that can explain such thing. I was thinking of just putting zero instead of negative values, but I'm not sure if that's a right approach. I would appreciate if someone can explain about the meaning of such negative values and how I can substitute such negative values with appropriate quantities.
• Welcome to DSP.SE! It sounds like the coordinates your call to peak is returning is in the padding area added by normxcorr2. Are you sure you are giving the yoffSet = ypeak-size(onion,1); call the correct image (i.e. your onion patch image). – Peter K. Sep 13 '17 at 16:05
• Thank you for your comment! Basically, to find yoffSet, and xoffSet, I need to subtract the first and second dimensions of the template image (the image with the smaller size), respectively, from ypeak and xpeak. So, the answer is yes. – Miranda Sep 13 '17 at 16:11 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6959337592124939, "perplexity": 454.8237784289604}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-39/segments/1568514573124.40/warc/CC-MAIN-20190917223332-20190918005332-00438.warc.gz"} |
https://cs.stackexchange.com/questions/88654/a-question-about-the-definition-of-prfs | # A question about the definition of PRFs
Let $$\mathcal{F} = \{ f_{s} \}_{s \in \{\, 0,1 \,\}^{*}}$$ be a family of computable functions, where $$f_{s} \colon \{\, 0,1 \,\}^{|s|} \rightarrow \{\, 0,1 \,\}^{|s|}$$.
We define a family of functions $$\mathcal{H} = \{ h_{s} \}_{s \in \{\, 0,1 \,\}^{*}}$$, where $$h_{s} \colon \{\, 0,1 \,\}^{|s|} \rightarrow \{\, 0,1 \,\}^{|s|}$$ and $$h_{s}\left( \cdot \right) = f_{s}\left( f_{s} \left( \cdot \right) \right)$$.
Let $$F_{n}$$ ($$H_{n}$$) be the distribution of functions $$f_{s}$$ ($$h_{s}$$), where $$s$$ is uniformly distributed over $$\{\, 0,1 \,\}^{n}$$. And let $$R_{n}$$ denote the uniform distribution over the set of all functions from $$\{\, 0,1 \,\}^{n}$$ to $$\{\, 0,1 \,\}^{n}$$.
We know that for any PPT adversary $$A$$, if for all $$n$$, $$\left\vert \Pr\left[ A^{F_{n}}\left( 1^n \right) = 1 \right] - \Pr\left[ A^{R_{n}}\left( 1^n \right) = 1 \right] \right\vert \leq \epsilon (n)$$ then $$\mathcal{F}$$ is a family of PRFs. And if $$\mathcal{F}$$ is a family of PRFs, then $$\mathcal{H}$$ is also a family of PRFs.
How about $$A$$ can only can query the oracle of a function sampled only one time? In other words, if $$\left\vert \Pr\left[ A\left( F_{n} \right) = 1 \right] - \Pr\left[ A\left( R_{n} \right) = 1 \right] \right\vert \leq \epsilon (n)$$ holds true, can we get that $$\left\vert \Pr\left[ A^{F_{n}}\left( 1^n \right) = 1 \right] - \Pr\left[ A^{R_{n}}\left( 1^n \right) = 1 \right] \right\vert \leq \epsilon (n)$$
PS: The title may not clear enough, but I don't know how to make it better :(. Thanks for anyone helping me to make it better :).
• There's something wrong with your question setup. A PRF takes two inputs: a value in $\{0,1\}^n$, and a key. Your function $f_n$ takes only one input. So, syntactically, it can't be a PRF. It's also not clear to me what you mean by "the distribution of functions $f_n$". You might want to check your understanding of the definitions. Once you fix that up, you'll find that a simple counterexample is $f(k,x) = k \oplus x$. – D.W. Feb 27 '18 at 16:33
• @D.W. You are right, I wrote the correct definition at the first time, and I decided to simplify it. And I did not realize that it is wrong. – TeamBright Mar 3 '18 at 7:33
Let $F_n$ be a random involution induced by a random perfect matching on $\{0,1\}^n$. For any input $x$, the distributions of $F_n(x)$ and $R_n(x)$ are almost identical (in fact, $F_n(x)$ has the same distribution as $R_n(x)$ conditioned on the event $R_n(x) \neq x$, which occurs with probability $1-2^{-n}$), so they are statistically indistinguishable. However, $H_n$ is the identity function, so it is easy to distinguish from a random function.
• There is a one more question about the definition, can you help me? The definition of PRFs in wiki says that $F_{n}$ is the distribution of functions $f_{s}$, where $s$ is uniformly distributed over $\{\, 0,1 \,\}^{n}$. But as I know, $F_{n}$ is the distribution of functions $f_{s}$, where $s$ if fixed at first, right? Does the definition correct? – TeamBright Mar 4 '18 at 7:45
• If $s$ is fixed then the distribution is concentrated on a single function! What would $s$ be fixed to? Rather, you should think of $s$ as a key or randomness which is used to generate the function. If this confuses you, I suggest reading $f$ instead of $f_s$. – Yuval Filmus Mar 4 '18 at 10:41
• Let $D_{1}$ and $D_{2}$ be two distributions. I notice even though they are statistically indistinguishable, maybe there still exists an oracle algorithm $D$ which can distinguish them. Why? I think that two distributions are statistically indistinguishable means that they cannot be distinguished even if $D$ has infinite power. – TeamBright Mar 6 '18 at 7:31
• Two distributions are statistically indistinguishable if their statistical distance is negligible (smaller than inverse polynomial). The statistical distance is the advantage of the best algorithm which tries to separate the two distributions (i.e., the maximum of $|\Pr[D(D_1)=1] - \Pr[D(D_2)=1]|$ over all oracle algorithms $D$). – Yuval Filmus Mar 6 '18 at 12:33 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 23, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9407903552055359, "perplexity": 137.58014901933575}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-47/segments/1573496668716.22/warc/CC-MAIN-20191115222436-20191116010436-00295.warc.gz"} |
https://brilliant.org/problems/add-a-reciprocal-repeat/ | Algebra Level 5
Let $a_n$ be a sequence of positive real numbers defined by $a_ 1 = 1$ and
$a_{n+1} = a_n + \frac{1}{a_n} \text{ for } n\geq 1.$
Evaluate $\lfloor a_{100000} \rfloor$.
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http://mathhelpforum.com/calculus/154022-odd-even-functions.html | Thread: Odd and Even functions
1. Odd and Even functions
Prove that:
a) if f(x) is an even function, $\displaystyle \int^a_{-a}f(x)dx=2\int^a_0 f(x)dx$
b)if f(x) is an odd function, $\displaystyle \int^a_{-a} f(x)dx=0$
I tried using proof by contradiction:
f(x) is even, then $\displaystyle \int^a_{-a}f(x)dx\neq 2\int^a_0 f(x)dx$
My problem is I don't know how to continue.
I figure if I get the first one right I can do the other.
Thanks!
2. You have to use the conditions on even and odd functions. I would then break up both LHS integrals into two pieces: one on either side of the origin. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9536302089691162, "perplexity": 278.2577153501429}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-22/segments/1526794867559.54/warc/CC-MAIN-20180526151207-20180526171207-00310.warc.gz"} |
https://stats.stackexchange.com/questions/321532/predicting-values-using-quantile-regression | # Predicting values using quantile regression
I entirely rewrote the question, since it was marked as unclear.
Suppose I have a linear regression model $Y=b_0+b_1 X_i+\epsilon$ for a time series dataset that consists of $Y$ and $X$.
I can now estimate $b_0$ and $b_1$ for different quantiles of $Y$: $bq_0$ and $bq_1$
Question 1: I have estimated $bq_0$ and $bq_1$ for the 0.1-quantile. Inserting new data for $X_i$ into the estimated regression model gives me with the 0.1 quantile of the new $Y$. Is this correct?
Question 2: To my understanding, quantile regression estimates the quantiles conditional on the specific quantile of $Y$. Is there a way to estimate effects conditional on the quantile of $X$? If so, one could construct a regression model that automatically changes it estimators, if $X$ reaches specific values. For example if $X$ is above the median, $bq_1$ is 1. If $X$ is below the median, $bq_1$ is 0.5.
Question 3: How do you cross validate the result from a quantile prediction for a time series? In the case of OLS for example, you could just compare the actual time series for year X, with the one you predicted for the year X. So if I had predicted one value for each month, I could compare this with the actual value for each month and see if it matches. How would you do this in case of quantile regression? If I predicted the 0.1 quantile for this case, I would have 12 data points that would represent the 0.1 quantile of the predicted distribution. Comparing this with the actual data does not make sense in my eyes.
I am sorry for being a bit confusing first. That is probably due to my lack of understanding of the topic. I hope it is clear what I am asking now.
• You can apply an estimated quantile regression to a new dataset in exactly the same way as an OLS regression. Of course the regressors should be semantically the same and measured in the same way in the training and the test dataset - but this applies equally to quantile and "normal" regression. Can you clarify what you are looking for? What is your original and new dataset? – Stephan Kolassa Jan 4 '18 at 15:31
• Thank you for your comment. See the edit please. The data is semantically the same and measured in the same way in both datasets. – shenflow Jan 4 '18 at 16:12
• I mean I know I can just insert new data in a single quantile regression estimation. But that would not make any sense, because I am putting data into a model that is designed to explain just a part of it (a quantile). – shenflow Jan 4 '18 at 16:17
• Well, if you run a quantile regression for the 80% quantile, then feeding new data into the model will predict the 80% quantile for the new data. A quantile prediction is often very useful, and I have tried using quantile regression in exactly this way. – Stephan Kolassa Jan 4 '18 at 16:21
• 0.1 refers to a proportion, not to a value of the response. E.g. 0.5 is the median. This value is known "beforehand", it does not depend on the response. – Michael M Jan 4 '18 at 16:28 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7323553562164307, "perplexity": 283.1977323770765}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-34/segments/1596439737019.4/warc/CC-MAIN-20200806180859-20200806210859-00316.warc.gz"} |
https://www.earthdoc.org/content/papers/10.3997/2214-4609-pdb.24.A21 | 1887
### Abstract
A21 Gas Flooding a Tight and Heterogeneous Silicilite Reservoir – Quantification of Sweep Efficiency H. Al-Shuraiqi* (Petroleum Development Oman) & V. van Engelen (Petroleum Development Oman) SUMMARY The Al Noor field was discovered in 1989 in the South Oman salt basin. The field is at a depth of 4 km and contains the unique Athel silicilyte. The reservoir has a gross thickness of around 400 m and is fully encased in sealing salt as a result of which the reservoir is geopressured to 80 MPa. The permeability is extremely low (typical 1 – 100 micro-darcy) due to the fact that
/content/papers/10.3997/2214-4609-pdb.24.A21
2007-04-22
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https://www.physicsforums.com/threads/can-anyone-explain-to-me-why-this-works-calculating-power-w-voltage-and-resistance.614457/ | # Can anyone explain to me why this works? Calculating power w/ voltage and resistance
1. Jun 16, 2012
### varyvod001
1. The problem statement, all variables and given/known data
An outdoor heater has a resistance of 50 ohms and operates at 275 V. A transformer connected to a 120-V source supplies electricity to the heater. What is the power used by the transformer?
2. Relevant equations
P = V^2/R
3. The attempt at a solution
I plugged in the values V and R from the heater and calculated to get 1512.5 W. This is, coincidentally, the answer on my answer key, but I don't understand why...Why does calculating the power of the object give me the power of the heater and where does the 120-V part come in? :/
2. Jun 16, 2012
### Martinet
Re: Can anyone explain to me why this works? Calculating power w/ voltage and resista
Power is given by P = VI.
V, voltage, is energy per charge (Joules per coulomb)
I, current, is charge per time (Coulombs per second)
From this we can see that if we increase the voltage, the overall energy output will increase.
We can also see that if we increase the current, the same will happen. This is because there are more charges at a given voltage, therefore more energy.
Now we know P = IV. So where does V^2/R come from?
Ohm's law: V = IR.
When we rearrange, we get I = V / R.
Think about I = V / R and P = VI.
See what you come up with.
EDIT: Having read TSny's post and then yours again I realised I misinterpreted your question. I'll leave what I wrote here though in case it's useful.
Last edited: Jun 16, 2012
3. Jun 16, 2012
### TSny
Re: Can anyone explain to me why this works? Calculating power w/ voltage and resista
varyvod001,
Not sure what "object" you are referring to when you say that you calculated the power of the "object". Seems to me you calculated the power used by the heater. Note that the question asks for the power used by the transformer.
The power used by the transformer is the power input to the transformer at 120 V. The transformer changes the input voltage of 120 V to the output voltage of 275 V. The power output by the transformer is the power used by the heater (which you have calculated).
So, you need to determine how the power that is input to a transformer is related to the power that is output by the transformer. Did you study this? The answer is pretty simple
4. Jun 16, 2012
### varyvod001
Re: Can anyone explain to me why this works? Calculating power w/ voltage and resista
I understand why the particular equation works in coming up with power. But I don't understand why using the resistance and voltage of the heater worked in calculating the power of the transformer. :)
Edit: So I calculated the output...And it works because the power input and output have to be the same, then?
I studied it....but I didn't really absorb a lot yet. :P
5. Jun 16, 2012
### TSny
Re: Can anyone explain to me why this works? Calculating power w/ voltage and resista
Yes, for an ideal transformer, the power input equals the power output. (For a real transformer there is some loss of power to internal heating. But real transformers can be close to ideal.)
6. Jun 16, 2012
### varyvod001
Re: Can anyone explain to me why this works? Calculating power w/ voltage and resista
Oh, okay...Makes sense now! Thank you very very very much! :D | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9223941564559937, "perplexity": 857.9915490553775}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-13/segments/1521257645550.13/warc/CC-MAIN-20180318071715-20180318091715-00416.warc.gz"} |
http://www.flyingcoloursmaths.co.uk/6times4-4times6/ | # $6\times4$ or $4\times6$?
Every so often, a question that comes up that looks incredibly trivial, but - no matter how much each side protests that the preference doesn't really matter - sets down clear divides in the maths community.
My podcasting partner in crime-fighting @reflectivemaths (Dave Gale in real life) stumble upon such a question the other day: does $4 \times 6$ mean four groups of six or six groups of four?
### Of course it doesn't sodding matter
One of the first things you learn about maths is that it doesn't matter which way you multiply things: like addition, multiplication commutes on the real numbers1 - you're within your rights to see $4\times6$ as either four groups of six, six groups of four, or even both at the same time (a position I suspect most mathematicians instinctively hold).
But still: almost everyone comes down on one side or the other.
Oh, poor @reflectivemaths and his muddleheaded simpleness. Dave believes, bless his little plastic pocket protector, that $4 \times 6$ means six groups of four, reasoning wrongly that you'd say it as "4 multiplied by 6", which means you start with four things and then create six groups of the same size. It's a seductive argument, and one that's hard to find proper fault with, which is obviously why I've resorted to the ad-homs before I put the case for my side of the story.
Instead of saying Dave's argument is wrong, I'm going to show that mine is right.
### Argument 1: Nanny Pat's times tables
"Twice six," my grandmother probably chanted in school, "is twelve." Not, you'll note, "six twice." Similarly, "Thrice six is eighteen, four times six is 24."
The notation $4 \times 6$, which I'd say as "four times six" as that's how I learnt my times tables, too, clearly means four groups of six - the version of it where you say "twice" or "thrice" gives it away - that's the number of groups.
### Argument 2: Algebraic convention
$3x$ - or three times $x$ - is almost impossible to think of as anything other than three groups, each with $x$ in. The algebraic convention is that the number of things always goes before the variable: you'd never write $x3$, not least because you'd get it mixed up with $x^3$ unless your handwriting was splendid.
### Argument 3: Linguistic convention
Literally the only example I can think of, in either of the two languages I can speak well, or either of the three languages I can speak awfully, of the number of groups following the contents of the group is Old King Cole's "fiddlers three" - which, in itself, is only there to make a pretty poor rhyme. In almost any other situation, saying the number of things after the things themselves means the ordinal: Toy Story 3 is the third Toy Story movie, not the set of three movies.
Even in pop groups like the Dave Clark 5, it's not that there are five Dave Clarks, just five people let by Dave Clark.
### Argument 4: $n$ times
Here's the clincher:
$\underset{\overbrace{x+x+\cdots+x+x}}{n\, times}$
This is not $x$ times $n$, it's $n$ times $x$.
### Argument 5: @reflectivemaths is a poopyhead
There, I said it.
Probably best to close with an ad-hom as well, just for the sake of good form.
### In conclusion
On this point of utter triviality, @reflectivemaths is clearly - clearly in the wrong. It's ok, though, it doesn't necessarily make him a bad person.
## Colin
Colin is a Weymouth maths tutor, author of several Maths For Dummies books and A-level maths guides. He started Flying Colours Maths in 2008. He lives with an espresso pot and nothing to prove.
1. and the complex numbers, since you ask - but not the quaternions or matrices, or non-Abelian groups. But I digress. []
### 4 comments on “$6\times4$ or $4\times6$?”
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https://www.physicsforums.com/threads/signal-noise-and-unequal-variances.228492/ | # Signal, noise, and, unequal variances
1. Apr 13, 2008
### Math Is Hard
Staff Emeritus
I have two overlapping Gaussian distributions. One for probability of a noise event, one for probability of a signal event.
My noise distribution has mean = 0, variance = 1, and standard deviation = 1.
My signal distribution has mean = .80, variance = 3, and standard deviation = √3.
My criterion (λ ) is at 0.5 standard deviations above the mean on the noise distribution.
I need to calculate probability of a hit (PH) and probability of a false alarm (PF).
To get PF , I use 1- PCorrect Rejection, or 1 – Ф(0.5), which, using a Z to % conversion table, gives me 1- 0.691 = 0.31. (In my book, Ф(Z) just means converting a Z-score to % of area under the curve.)
To get PH, I first need to standardize the Z score for λ on the signal distribution since it has a different variance:
λ = (λ - μsignal)/σ signal = (0.5-0.8) / √3 = - 0.173
PH = 1 - Ф(-0.173) or by symmetry, PH = Ф(0.173) = 0.57. (again, using a Z to % conversion table to look up the area.)
So.. PF = = 0.31 and PH = 0.57.
I'm not sure if I did this right. I am shaky with unequal variances. If someone could check I'd appreciate it.
I need to sketch the overlapping distributions. Since I have standardized the z-score on the signal distribution, do I make it look identical to the noise curve (with a standard deviation of 1), or do I draw it short and wide as it is originally described?
Thanks!
Can you offer guidance or do you also need help?
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https://link.springer.com/article/10.1007/s00191-020-00683-7?error=cookies_not_supported&code=6f4604d0-2085-46ac-8f59-ffb83fa92550 | # Heterogeneous expectations, forecasting behaviour and policy experiments in a hybrid Agent-based Stock-flow-consistent model
## Abstract
This paper presents a hybrid agent-based stock-flow-consistent model featuring heterogeneous banks, purposely built to examine the effects of variations in banks’ expectations formation and forecasting behaviour and to conduct policy experiments with a focus on monetary and prudential policy. The model is initialised to a deterministic stationary state and a subset of its free parameters are calibrated empirically in order to reproduce characteristics of UK macro-time-series data. Experiments carried out on the baseline focus on the expectations formation and forecasting behaviour of banks through allowing banks to switch between forecasting strategies and having them engage in least-squares learning. Overall, simple heuristics are remarkably robust in the model. In the baseline, which represents a relatively stable environment, the use of arguably more sophisticated expectations formation mechanisms makes little difference to simulation results. In a modified version of the baseline representing a less stable environment alternative heuristics may in fact be destabilising. To conclude the paper, a range of policy experiments is conducted, showing that an appropriate mix of monetary and prudential policy can considerably attenuate the macroeconomic volatility produced by the model.
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## Notes
1. Although they are often broadly comparable in that SFC models frequently incorporate behavioural assumptions based on the post-Keynesian paradigm (Lavoie 2014).
2. Indeed, even in many otherwise fully-fledged macro-ABMs (e.g. in Assenza et al. (2015) and Seppecher 2012), it is assumed for simplicity that there exists a unique/representative bank.
3. This latter paradigm is arguably closest to the concept of rationality espoused in macroeconomic ABMs.
4. In a stationary state it must be the case that vh = vh,− 1, which implies cd = yd(= yde = c) and hence $$\frac {v_{h}}{yd}=\frac {1-\alpha _{1}}{\frac {\alpha _{2}}{48}}$$
5. In addition to these assets, households are also assumed to privately own the firms and banks in the model. However, as firm and bank equity are assumed to be non-tradeable their rates of return do not enter into the computation of the consumption propensities as households cannot decide to save more or less in order to accumulate more or less firm or bank equity.
6. This implies that monetary policy prima facie has an ambiguous effect on inflation; increases in the central bank rate will tend to decrease aggregate demand and economic activity, which will tend to lead to lower wages and hence prices, but will also increase unit interest cost, which tends to lead to higher prices. The actual effect on the price level will depend on the relative strength of these effects. Such contradictory feedback channels can also be found in some DSGE models (e.g. Christiano et al. 2005).
7. It is assumed that banks always grant loans to firms which are purely aimed at financing replacement investment and only ration loan demand exceeding that needed for replacement investment.
8. In the case of firms, $$\overline {lev_{f}}$$ is a one-year moving average of the ratio of loans to capital.
9. The scripts necessary to reproduce the simulations can be downloaded from https://github.com/SReissl/JEEC.
10. Given the absence of competition, the loan and mortgage interest rate setting mechanism used by the single bank is changed such that it no longer compares its rate to the average rate (since these will obviously always be equal) but rather increases the mark-up on loans (mortgages) by a stochastic amount if its revenues on loans (mortgages) have been growing in the recent past and decreases it if the latter have been falling.
11. The numbers in Table 2 as well as all other tables below show the point-estimates and 95% confidence intervals from a Wilcoxon signed-rank test on the simulated statistics across the 100 MC repetitions of the respective simulations. The numbers reported in Table 2 on the other hand represent the unconditional means of the statistics which were used in the empirical calibration, explaining the slight difference between the baseline numbers reported in Table 1 and those shown below.
12. The parametrisation of the mechanism is as follows: ψad = 0.5, ψaa = 0.5, ψtf1 = 0.75, ψtf2 = 1.3, intensity of choice = 5, memonry parameter = 0.7. The functional forms exactly follow those suggested by Anufriev and Hommes (2012).
13. Note in particular that average forecast errors of both adaptive expectations and heterogeneous expectations with heuristic switching are not significantly different from zero.
14. In the case of stock variables, the chosen initial period is 1995 Q1.
15. There is clearly a danger for this algorithm to get ‘stuck’ at a local maximum of the objective function, but there is little I can do regarding this issue given limited time and computational resources, and the obtained results seem reasonably good.
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## Acknowledgements
The author would like to thank Domenico Delli Gatti, Herbert Dawid, Antoine Godin and Alessandro Caiani for their substantial input during the development of this paper. Insightful hints and comments from Alberto Cardaci, Jakob Grazzini, as well as participants at conferences in Berlin, Budapest, Milan and Bamberg are gratefully acknowledged. Comments from two anonymous referees led to a substantial improvement of the paper. The usual disclaimer applies.
## Funding
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 721846 (ExSIDE ITN)
## Author information
Authors
### Corresponding author
Correspondence to Severin Reissl.
## Ethics declarations
### Conflict of interests
The author declares that they have no conflict of interest.
### Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 721846 (ExSIDE ITN).
## Appendices
The tables below show the traditional balance sheet and transactions flow matrices which provide an overview of the aggregate SFC structure of the model.
### Appendix B: Initialisation, calibration and data sources
The model is initialised to a deterministic stationary state using a script in which initial values and as well as a range of parameters can be sequentially calculated based on the imposition of successive restrictions on some characteristics of the stationary state such as the capital stock, the stock of housing, the investment and government spending to income ratios, and so on. Where possible, these values are chosen so as to correspond roughly to those of the economy of the United Kingdom.Footnote 14 To give an example of how this calibration procedure works, once I impose a stationary state level of the capital stock, the capacity utilisation rate, and a parameter value for the capital depreciation rate, then investment demand,the capital to full capacity output ratio and real GDP are implied by these imposed values jointly with the assumed Leontieff production function and the assumption that the simulation begins in a stationary state. In a stationary state it must be the case that
$$i=i_{d}=\delta_{k}\cdot k,$$
(28)
i.e. capital investment must equal depreciation for the capital stock to be constant. Next, note that the production function implies
$$\kappa \cdot y = u\cdot k$$
(29)
where κ is the capital to full capacity output ratio. Next, I can substitute for k from Eq. 28 and rearrange to get
$$\kappa = u\cdot \frac{i}{y\cdot \delta_{k}}.$$
(30)
Having previously imposed a stationary state value for $$\frac {i}{y}$$ this gives me the value for κ which in turn I can use to get a value for y from Eq. 29. The rest of the initialisation protocol proceeds similarly. For instance, by imposing a stationary state value of the government expenditure to output ratio, I get a stationary state level of government expenditure and furthermore a value for consumption since
$$c=y-i-g.$$
(31)
In many cases, the stock-flow consistent accounting structure of the model is useful in this initialisation exercise as accounting conventions dictate the values of certain variables once a sufficient number of others are determined. Despite the imposition of successive restrictions, this procedure leaves a range of parameter values unidentified (in particular those appearing in behavioural equations written in terms of deviations from ‘normal’ or stationary state values). A subset of these are empirically calibrated below, while the rest are set to values which give rise to reasonable results and are subjected to a sensitivity analysis in online appendix C.
For the empirical calibration of free parameters I make use of the simulated minimum distance approach described by Grazzini and Richiardi (2015) by applying the method of simulated moments (see Gilli and Winker 2003; Franke and Westerhoff 2012; Schmitt 2018) in order to empirically calibrate 8 of the model’s free parameters. This is done through maximising an objective function involving a set of 8 moments/statistics calculated from empirical data along with their equivalents generated by model simulations. In particular, the function to be maximised is
$$O(\theta)=-(m_{d}(\theta_{0})-m(\theta))'\cdot W \cdot (m_{d}(\theta_{0})-m(\theta))$$
(32)
where 𝜃 is a vector of model parameters (with 𝜃0 being the vector of their ‘true’ values), md is a vector of empirical moments and m(𝜃) is a vector of simulated moments. W is a weighting matrix. Following Franke and Westerhoff (2012), the weighting matrix used here is the inverse of the variance-covariance matrix of the empirical moments/statistics, which is obtained through the use of bootstrapping. This ensures that the variance of the empirical moments is taken into account in the calibration procedure.
As outlined by Grazzini and Richiardi (2015), building on Grazzini (2012), the use of simulated minimum distance estimators in agent-based models raises the issues of stationarity and ergodicity, in that a simulated minimum distance estimator will only be consistent if the simulated moments/statistics used are stationary and ergodic. Note that Eq. 32 is somewhat misleading in that in an agent-based model, m may be a function not only of 𝜃 but also of the random seed s and the vector of initial conditions y0 and may in particular be non-ergodic w.r.t. the random seed and/or the initial conditions. Having observed the behaviour of the model across a large number of simulations, it appears reasonable to assume that the stationarity assumption is fulfilled for the simulated moments I use, in particular since I apply the HP-filter to the simulated data before calculation of the objective function. The ergodicity assumption w.r.t. the random seed and initial conditions is somewhat more problematic but I can at least partly overcome this issue on the one hand by choosing initial conditions based on empirical information as far as possible and subsequently keeping them fixed across simulations, and on the other hand by defining m as the Monte-Carlo average of moments from a set of simulations with different random seeds, for which in turn the ergodicity assumption appears less heroic.
More broadly, the empirical calibration procedure is used here primarily to arrive at a reasonable baseline simulation without having to fully parametrise the model by hand, rather than to consistently estimate the ‘true’ values of the parameters (all the more so since, as outlined below, I am not able to cover the entire parameter space in my simulations and instead rely on sampling). The time-series I choose for the empirical calibration procedure are quarterly real GDP, real consumption, real investment and the CPI for the UK from 1994 Q2 until 2019 Q1, such that the length of the empirical time series is equal to that of the simulated ones (all simulations shown below, as well as those used for the empirical calibration have a post-transient duration of 25 years). I apply the HP-filter to each empirical time series and then calculate the standard deviation and first order autocorrelation of each series’ percentage-deviation from its trend component. The same procedure is applied to the simulated quarterly time series which are constructed from the weekly model output. The vector of parameters I am aiming to calibrate consists of the parameters shown in Table 13.
The empirical calibration proceeds by sampling the parameter space made up of the eight parameters within the ranges shown in Table 13 above using latin hypercube sampling, simulating each parameter configuration 100 times with different (reproducible) seeds and calculating the values of the objective function. Sampling is then repeated around points which appear promising in terms of the value of the objective function until eventually a satisfactory configuration is reached in the sense that further sampling and simulation generates no notable improvements in the value of the objective function.Footnote 15
The sources of the data used to empirically calibrate the model are as follows:
• Real GDP (quarterly): Office for national statistics; Source dataset: QNA; CDID: ABMI
• Real consumption (quarterly): Office for national statistics; Source dataset: PN2; CDID: ABJR
• Investment (quarterly): OECD; Subject P51
• Price level/CPI (quarterly): Office for national statistics; Source dataset: MM23; CDID: D7BT
Table 14 below shows the values of all parameters and exogenous variables used in the baseline simulation. In addition it shows whether a given value is empirically calibrated (“emp”), imposed to produce the initial stationary state (“pre-SS”), implied by the stationary state (“SS-given”), or free. Where applicable, the range of values used for the sensitivity analysis is also shown. For parameters and initial values which need to be set “pre-SS” (i.e. they are needed to identify the initial stationary state rather than being implied by the latter or being calibrated empirically), I try where possible to use rough empirical values. Thus for instance, the fixed housing stock and the initial capital stock are set so as to roughly correspond to their empirical counterparts in the UK in 1995 Q1 according to the national balance sheet. Similarly, conditions such as the ratios of government consumption and capital investment to GDP, the labour share in GDP, depreciation and labour productivity are set to values close to their empirical counterparts. The conditions thus imposed are kept fixed across all simulations. Once a sufficient number of such conditions have been imposed, a large part of the remaining free parameters and initial values is implied by those already set together with the SFC structure and the assumption of a stationary state. Of the rest (category “free”), a subset is calibrated empirically as discussed above while most others are subjected to a sensitivity analysis which is discussed in online appendix C.
Table 15 below shows the aggregate initial values which are needed to initialise the model for the simulations shown in the paper. Variables pertaining to banks (e.g. stocks such as deposits, loans, mortgages etc. but also flows such as interest payments or profits) are set by imposing an initial market share for each bank (assumed equal in all markets) and then distributing each stock and flow according to these shares. The shares assumed here for the twelve banks are 0.13, 0.11, 0.11, 0.1, 0.09, 0.08, 0.07, 0.07, 0.06, 0.06, 0.06 and 0.06. Due to the way the model is set up, all banks offer equal rates on loans and deposits in the initial, deterministic stationary state. Initial values for flows refer to weekly values in all cases.
### Appendix C: Sensitivity analysis
Recall that in the baseline, the central bank follows a pure inflation-targeting policy rule. Here I generalise the policy rule to
$$r_{cb, d}=r_{0}+\pi^{e}+\phi_{\pi}\cdot (\pi^{e}-\pi^{t}) + \phi_{u}\cdot (u^{e}_{cb}-u_{n})$$
(33)
meaning that the central bank can also react to gaps between expected capacity utilisation and its normal or conventional value. In the baseline, ϕπ = 0.25 so that the Taylor principle holds (recall that πt = 0). I then simulate the model for a range of values for both parameters, the range being − 1 to 1 for ϕπ and 0 to 1.5 for ϕu with step-size 0.25 in both cases. All parameter combinations are simulated for 100 MC-repetitions as in the baseline. Note that if ϕπ < 0, the Taylor principle does not hold and when ϕπ = − 1 monetary policy does not react to inflation dynamics at all. Figures 16 and 17 show the response of the standard deviations of (filtered) real output and the (filtered) price-level to variations in ϕπ (axis label π) and ϕu (axis label u) using heatmaps.
It can be seen that simulation results are fairly sensitive to changes in the parametrisation of the monetary policy rule. A look at the results concerning ϕπ suggests that price level volatility is minimised around the value of ϕπ in the baseline (0.25), with ϕu being close to 0. Output volatility, on the other hand, is minimised then phiπ is close to zero while ϕu reacts moderately to utilisation gaps, suggesting a weak trade-off between price and output stabilisation. Overly strong reactions of monetary policy to output gaps, on the other hand, tend to lead to greater volatility in both output and inflation (indeed for high values of ϕu the model gives rise to extreme volatility or breaks down completely, which explains the missing observations in the plots). Similarly, very strong (but also very weak) reactions of monetary policy to inflation appear disadvantageous for macroeconomic stability.
In addition to the parameter sweep of the monetary policy rule, I conduct a basic sensitivity analysis on those 12 parameters for which a sensitivity range is shown in Table 14. This is done by varying the value of each parameter, one by one, along the range and according to the step sizes shown in the table. I simulate each parameter configuration for 100 Monte Carlo repetitions and compare the results to the baseline by inspecting time-series plots as well as the volatility of the time series which were used in calibrating the model. The results for variations in each parameter are discussed below in turn. Results indicate that most of the non-empirically calibrated parameters analysed here have little influence on model dynamics if varied along the ranges considered, suggesting that the choice of parameters for the empirical calibration procedure was broadly appropriate.
### ψ a d
: In contrast to varying only the expectations mechanism of banks, as was done in the experiments above, jointly varying the adaptation parameter in adaptive expectations for all sectors (including banks) at once has a slight effect on macroeconomic volatility. A larger (smaller) value of ψad leads tends to increase (decrease) fluctuations as expectations which feed into the determination of various decision-variables become more (less) sensitive to forecast errors.
### εd2
: A higher value of εd2 than in the baseline implies a greater sensitivity of the deposit rates offered by banks to their clearing position. Overall this increases the range of variation in deposit interest rates and also leads to greater short-term fluctuations in deposit rates. This in turn translates into a slight increase in macroeconomic volatility. In the case of a lower value for εd2 than in the baseline, the opposite applies
### σ I B
: An increase (decrease) in σIB, the sensitivity of the interbank interest rate to excess demand or supply on the interbank market obviously increases (decreases) the volatility of the interbank rate. Beyond this, however, there is no noticeable effect on model dynamics, which is in line with the passive role played by the interbank market in the model.
### ι1
: ι1 determines the sensitivity of banks’ market shares to interest rate differentials. Consequently, a higher value of ι1 leads to larger variations in market shares but for the range of values considered does not give rise to persistent monopolisation tendencies. The effects of varying ι1 on macroeconomic dynamics are slight, with higher (lower) values somewhat increasing (decreasing) the volatility of the price level due to larger variations in bank interest rates as a result of stronger (weaker) price competition.
### ι2
: At the level of individual banks, the effects of variations in ι2, which determines the sensitivity of banks’ market shares in loans and mortgages to their history of credit rationing, are similar to those caused by varying ι1. However, there is no significant effect on macroeconomic volatility for the range of values used here.
### AR d i s
: An increase or decrease in the persistence of shocks to the distribution of deposits and loan demand between banks does not appear to have any systematic impact on simulation outcomes for the range of values of the parameter which are considered here.
### σ d i s
: σdis denotes the standard deviation of shocks to the market shares of banks. Similarly to the effect of varying the persistence of these shocks, varying σdis along the range of values considered here has no significant impact on simulation outcomes.
### CC d e f
: As one might suspect, an increase (decrease) in the cross-correlation of default shocks among banks significantly increases (decreases) macroeconomic volatility. More systemic fluctuations in defaults produce an increased volatility of interest rates as well as greater correlation in the fluctuations of individual banks’ capital adequacy ratios, both of which feed back on the aggregate sectors and ultimately lead all macro time-series to become more volatile.
### step
: step gives the mean value of the normal distribution which banks use to draw mark-up revisions when changing their interest rates on loans and mortgages. Decreasing or increasing this mean value along the range indicated above has no significant impact on simulation outcomes.
### σ s t e p
: σstep is the standard deviation of the normal distribution which banks use to draw mark-up revisions when changing their lending rates. Varying the value of this parameter, similarly to what was found for step, does not significantly alter simulation results.
### ξ1
: ξ1 gives the upper bound of the rationing indicators on loans and mortgages calculated in Eq. 16, which feed into the distribution of loan and mortgage demand between banks. Varying this parameter has no effect on simulation results, suggesting that the indicators never reach their upper bound in the simulations considered.
### ξ2
: ξ2 measures the sensitivity of the credit rationing indicators to the intensity with which a bank rationed credit in the past. Varying this parameter along the range indicated above has no significant impact on model dynamics.
## Rights and permissions
Reprints and Permissions
Reissl, S. Heterogeneous expectations, forecasting behaviour and policy experiments in a hybrid Agent-based Stock-flow-consistent model. J Evol Econ 31, 251–299 (2021). https://doi.org/10.1007/s00191-020-00683-7
• Published:
• Issue Date:
• DOI: https://doi.org/10.1007/s00191-020-00683-7
### Keywords
• Stock-flow consistent models
• Agent-based models
• Expectations formation
• Monetary policy
• Prudential policy
• E12
• E52
• E58
• E61
• G28 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 2, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7469204664230347, "perplexity": 4281.09482513847}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-33/segments/1659882571472.69/warc/CC-MAIN-20220811133823-20220811163823-00566.warc.gz"} |
http://mitpdev.mit.edu/journal/10.1162/neco.1994.6.6.1233 | ## Neural Computation
November 1994, Vol. 6, No. 6, Pages 1233-1243
(doi: 10.1162/neco.1994.6.6.1233)
© 1994 Massachusetts Institute of Technology
Approximation Capability of Layered Neural Networks with Sigmoid Units on Two Layers
Article PDF (503.25 KB)
Abstract
Using only an elementary constructive method, we prove the universal approximation capability of three-layered feedforward neural networks that have sigmoid units on two layers. We regard the Heaviside function as a special case of sigmoid function and measure accuracy of approximation in either the supremum norm or in the Lp-norm. Given a continuous function defined on a unit hypercube and the required accuracy of approximation, we can estimate the numbers of necessary units on the respective sigmoid unit layers. In the case where the sigmoid function is the Heaviside function, our result improves the estimation of Kůrková (1992). If the accuracy of approximation is measured in the LP-norm, our estimation also improves that of Kůrková (1992), even when the sigmoid function is not the Heaviside function. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9807133674621582, "perplexity": 714.6812549173983}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-17/segments/1618039544239.84/warc/CC-MAIN-20210421130234-20210421160234-00606.warc.gz"} |
https://www.advanceduninstaller.com/DES-2_0-ff2c67fa971d33717bbfc6e1bb4e5c24-application.htm | DES 2.0
A way to uninstall DES 2.0 from your computer
This web page is about DES 2.0 for Windows. Here you can find details on how to uninstall it from your computer. It was coded for Windows by Gigabyte. You can read more on Gigabyte or check for application updates here. You can see more info on DES 2.0 at . The program is usually located in the C:\Program Files\Gigabyte\EnergySaver2 directory. Take into account that this path can vary being determined by the user's preference. DES 2.0's entire uninstall command line is C:\Program Files\InstallShield Installation Information\{675F86A8-E093-4002-87D5-915CC2C45571}\Setup.exe /UNINST. DES 2.0's primary file takes about 350.61 KB (359024 bytes) and is called des2.exe.
The following executables are incorporated in DES 2.0. They occupy 1.36 MB (1423704 bytes) on disk.
• des2.exe (350.61 KB)
• des2svr.exe (66.54 KB)
• GBTUpd.exe (455.04 KB)
• ReLaunch.exe (210.61 KB)
• UpdExe.exe (307.54 KB)
The current web page applies to DES 2.0 version 1.00.0000 only. If you are manually uninstalling DES 2.0 we advise you to check if the following data is left behind on your PC.
Folders that were found:
• C:\Program Files (x86)\Gigabyte\EnergySaver2
The files below remain on your disk by DES 2.0 when you uninstall it:
• C:\Program Files (x86)\Gigabyte\EnergySaver2\AdvEng.dll
• C:\Program Files (x86)\Gigabyte\EnergySaver2\AdvSC.dll
• C:\Program Files (x86)\Gigabyte\EnergySaver2\AdvTC.dll
• C:\Program Files (x86)\Gigabyte\EnergySaver2\CheckFK.dll
• C:\Program Files (x86)\Gigabyte\EnergySaver2\des2.exe
• C:\Program Files (x86)\Gigabyte\EnergySaver2\DES2_CHI.chm
• C:\Program Files (x86)\Gigabyte\EnergySaver2\DES2_ENG.chm
• C:\Program Files (x86)\Gigabyte\EnergySaver2\des2svr.exe
• C:\Program Files (x86)\Gigabyte\EnergySaver2\eng.dll
• C:\Program Files (x86)\Gigabyte\EnergySaver2\ExeVer.ini
• C:\Program Files (x86)\Gigabyte\EnergySaver2\GBTUpd.exe
• C:\Program Files (x86)\Gigabyte\EnergySaver2\GVTunner.dll
• C:\Program Files (x86)\Gigabyte\EnergySaver2\INFO.DAT
• C:\Program Files (x86)\Gigabyte\EnergySaver2\ReLaunch.exe
• C:\Program Files (x86)\Gigabyte\EnergySaver2\Res.dll
• C:\Program Files (x86)\Gigabyte\EnergySaver2\Satae.log
• C:\Program Files (x86)\Gigabyte\EnergySaver2\SC.dll
• C:\Program Files (x86)\Gigabyte\EnergySaver2\server.dat
• C:\Program Files (x86)\Gigabyte\EnergySaver2\SF.dll
• C:\Program Files (x86)\Gigabyte\EnergySaver2\TC.dll
• C:\Program Files (x86)\Gigabyte\EnergySaver2\UpdExe.exe
• C:\Program Files (x86)\Gigabyte\EnergySaver2\verinfo.ini
• C:\Program Files (x86)\Gigabyte\EnergySaver2\ycc.dll
Registry that is not cleaned:
• HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall\{675F86A8-E093-4002-87D5-915CC2C45571}
Supplementary values that are not removed:
• HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DES2 Service\ImagePath
A way to remove DES 2.0 with the help of Advanced Uninstaller PRO
DES 2.0 is a program released by the software company Gigabyte. Sometimes, computer users want to remove this program. Sometimes this can be difficult because deleting this by hand requires some experience regarding PCs. The best EASY manner to remove DES 2.0 is to use Advanced Uninstaller PRO. Here are some detailed instructions about how to do this:
1. If you don't have Advanced Uninstaller PRO already installed on your system, install it. This is good because Advanced Uninstaller PRO is a very potent uninstaller and all around tool to take care of your system.
• install Advanced Uninstaller PRO
2. Start Advanced Uninstaller PRO. It's recommended to take your time to admire Advanced Uninstaller PRO's interface and number of features available. Advanced Uninstaller PRO is a very good system utility.
3. Click on the General Tools button
4. Activate the Uninstall Programs tool
5. A list of the programs installed on your computer will be made available to you
6. Navigate the list of programs until you locate DES 2.0 or simply click the Search feature and type in "DES 2.0". The DES 2.0 application will be found automatically. After you select DES 2.0 in the list of programs, the following data about the program is made available to you:
• Star rating (in the left lower corner). The star rating tells you the opinion other people have about DES 2.0, from "Highly recommended" to "Very dangerous".
• Opinions by other people - Click on the Read reviews button.
• Technical information about the application you are about to uninstall, by clicking on the Properties button.
For instance you can see that for DES 2.0:
• The publisher is: http://www.Gigabyte.com
• The uninstall string is: C:\Program Files\InstallShield Installation Information\{675F86A8-E093-4002-87D5-915CC2C45571}\Setup.exe /UNINST
7. Click the Uninstall button. A window asking you to confirm will appear. accept the removal by clicking the Uninstall button. Advanced Uninstaller PRO will then remove DES 2.0.
8. After uninstalling DES 2.0, Advanced Uninstaller PRO will ask you to run a cleanup. Press Next to perform the cleanup. All the items that belong DES 2.0 which have been left behind will be found and you will be able to delete them. By removing DES 2.0 using Advanced Uninstaller PRO, you can be sure that no Windows registry items, files or folders are left behind on your disk.
Your Windows PC will remain clean, speedy and able to run without errors or problems.
Disclaimer
This page is not a recommendation to remove DES 2.0 by Gigabyte from your PC, nor are we saying that DES 2.0 by Gigabyte is not a good application. This text only contains detailed instructions on how to remove DES 2.0 in case you decide this is what you want to do. The information above contains registry and disk entries that Advanced Uninstaller PRO discovered and classified as "leftovers" on other users' PCs.
2016-06-19 / Written by Andreea Kartman for Advanced Uninstaller PRO | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9937978386878967, "perplexity": 10054.421970483703}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-25/segments/1623487584018.1/warc/CC-MAIN-20210612132637-20210612162637-00216.warc.gz"} |
http://www.zcu.cz/research/publications/?id=43909536 | Přejít k obsahu
### Metric regularity and convergence of iterative schemes
Citace: CIBULKA, R. Metric regularity and convergence of iterative schemes. Technische Universität Wien, 2014. PŘEDNÁŠKA, POSTER eng Metric regularity and convergence of iterative schemes 2014 Ing. Radek Cibulka Ph.D. Given Banach spaces $X$ and $Y$, a single-valued (possibly non-smooth) mapping $f: X \to Y$ and a multivalued mapping $F:X\rightrightarrows Y$, we investigate the properties of the solution mapping corresponding to a generalized equation: $$\label{Eqn1} \mbox{Find}\quad x\in X \quad \mbox{such that}\quad 0\in f(x)+F(x).$$ This model has been used to describe in a unified way various problems such as equations, inequalities, variational inequalities, and in particular, optimality conditions. In the first part, we present a result concerning the stability of metric regularity under (set-valued) perturbations as well as an infinite-dimensional generalization of the Izmailov's theorem \cite{I} which is an extension both of the Clarke's theorem \cite{Clarke} and finite-dimensional version of the Robinson's theorem \cite{R}. In the latter part, we study the convergence properties of the following iterative process for solving \eqref{Eqn1}: {\it Choose a sequence of set-valued mappings $A_k: X\times X\rightrightarrows Y$ approximating the function $f$ and a starting point $x_0 \in X$, and generate a sequence $(x_k)$ in $X$ iteratively by taking $x_{k+1}$ to be a solution to the auxiliary generalized equation $$\label{Newton-Seq} 0\in A_k(x_{k+1},x_k)+F(x_{k+1}) \quad \mbox{for each} \quad \quad k \in \{0,1,2, \dots\}.$$} The results from the first part are applied in the study of (super-)linear convergence of (\ref{Newton-Seq}). Especially, several particular cases are discussed in detail. The presentation is based on the forthcoming paper with Samir Adly and Huynh Van Ngai as well as on the one with Asen L. Dontchev.
Zpět | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 2, "x-ck12": 0, "texerror": 0, "math_score": 0.9674950242042542, "perplexity": 609.7348120196607}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-05/segments/1516084887535.40/warc/CC-MAIN-20180118171050-20180118191050-00122.warc.gz"} |
https://podcasts.apple.com/za/podcast/ep-25-you-are-not-weak-a-short-poem/id1287141836?i=1000424064186 | 2 min
# Ep 25 - You Are Not Weak - A short poem Master The Mind, Master Anything with Dave Cottrell
• Mental Health
You Are Not Weak
You are not weak
The journey is just difficult
And someone, somewhere told you that it "should" be easy.
And when it wasn't you believed that the problem was you.
You said "why can't I do this?"
Or maybe even "what's wrong with me"
But the problem was never you
The journey is just difficult
When we ask "why can't" then we see only problems
But when we ask "how could" then the solutions emerge
Solutions that emerge from your mind
A mind that is strong, that is resourceful
You were never weak,
you were just tricked to think you were
You were asking the wrong questions
and as a result getting the wrong answers
The journey is difficult, yes it is true
But you are formidable
And there's nothing you can't do
You Are Not Weak
You are not weak
The journey is just difficult
And someone, somewhere told you that it "should" be easy.
And when it wasn't you believed that the problem was you.
You said "why can't I do this?"
Or maybe even "what's wrong with me"
But the problem was never you
The journey is just difficult
When we ask "why can't" then we see only problems
But when we ask "how could" then the solutions emerge
Solutions that emerge from your mind
A mind that is strong, that is resourceful
You were never weak,
you were just tricked to think you were
You were asking the wrong questions
and as a result getting the wrong answers
The journey is difficult, yes it is true
But you are formidable
And there's nothing you can't do
2 min | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8524041175842285, "perplexity": 5830.059992841041}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-17/segments/1618038085599.55/warc/CC-MAIN-20210415125840-20210415155840-00206.warc.gz"} |
https://community.boredofstudies.org/threads/projectile-motion-methods.339185/ | # Projectile motion methods (1 Viewer)
##### New Member
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Hi
I was wondering whether or not you can use other methods of doing projectile motion questions. Could I use the calculus based method I learnt in extension 1 maths?
#### rand_althor
##### Active Member
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Messages
554
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Pretty sure you can't. You have to use the formulas on the formula sheet.
#### astroman
##### Well-Known Member
Joined
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No you can't, you have to do the way the syllabus teaches you.
##### New Member
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Euugh, using the formulas is so clunky.
#### InteGrand
##### Well-Known Member
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Euugh, using the formulas is so clunky.
It's usually actually easier, since the only difference with the calculus method is that you derive the equations of motion first. In HSC Physics, you're allowed to just quote them. And you don't need to use the exact symbols in the formulae as printed in the formula sheet (like with $\Delta x = u_x t$ etc.), you can use more convenient symbols if you like, like saying $x = V \cos \theta t$ etc. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 2, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7819688320159912, "perplexity": 1848.6313321619314}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-26/segments/1560627998084.36/warc/CC-MAIN-20190616082703-20190616104703-00093.warc.gz"} |
https://discourse.panda3d.org/t/usermanagesmemory-error-when-creating-lerpposinterval/766 | # 'userManagesMemory' Error when creating LerpPosInterval
Hello all,
When trying to setup a LerpPosInterval i got the following Error:
AssertionError
Exception exceptions.AttributeError:
‘userManagesMemory’" in ignored
I’m setting my intervall with the following command:
self.intervals.append(LerpPosInterval(model, duration, newPos, startPos,reference,
blendType,bakeInStart , fluid , IntervalName))
and the parameters have the following values:
Entity ->Enabl
model:
[NodePath at: 122386520]
render/DeviceSphinx
Interval Name:
TestPosInterval
Duration:
1
BakeInStart:
0
BlendType:
NoBlend
StartPos:
[Point3 at: 132295576]
0 0 0
NewPos:
[Point3 at: 122993368]
1 1 1
Fluid:
0
Do you have a hint about what is wrong with this declaration?
That is very strange. I think that particular error message can only be triggered when an object is trying to destruct. Is it possible something is not quite right with the way you are saving the interval? Can you create the same interval safely in other contexts?
David
Ok i found out the error. It was simply the case of the blendType parameter that was wrong. I was passing “NoBlend” instead of “noBlend” | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8246184587478638, "perplexity": 3042.684089106153}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-33/segments/1659882570765.6/warc/CC-MAIN-20220808031623-20220808061623-00285.warc.gz"} |
https://questions.examside.com/past-years/jee/question/presistance-of-the-wire-is-measured-as-2-omega-and-3-jee-main-physics-motion-dtdtff3jwacwt8do | 1
JEE Main 2022 (Online) 28th June Evening Shift
MCQ (Single Correct Answer)
+4
-1
Resistance of the wire is measured as 2 $$\Omega$$ and 3 $$\Omega$$ at 10$$^\circ$$C and 30$$^\circ$$C respectively. Temperature co-efficient of resistance of the material of the wire is :
A
0.033 $$^\circ$$C$$-$$1
B
$$-$$0.033 $$^\circ$$C$$-$$1
C
0.011 $$^\circ$$C$$-$$1
D
0.055 $$^\circ$$C$$-$$1
2
JEE Main 2022 (Online) 27th June Evening Shift
MCQ (Single Correct Answer)
+4
-1
Two long parallel conductors S1 and S2 are separated by a distance 10 cm and carrying currents of 4A and 2A respectively. The conductors are placed along x-axis in X-Y plane. There is a point P located between the conductors (as shown in figure).
A charge particle of 3$$\pi$$ coulomb is passing through the point P with velocity $$\overrightarrow v = (2\widehat i + 3\widehat j)$$ m/s; where $$\widehat i$$ and $$\widehat j$$ represents unit vector along x & y axis respectively.
The force acting on the charge particle is $$4\pi \times {10^{ - 5}}( - x\widehat i + 2\widehat j)$$ N. The value of x is :
A
2
B
1
C
3
D
$$-$$3
3
JEE Main 2022 (Online) 27th June Morning Shift
MCQ (Single Correct Answer)
+4
-1
A 72 $$\Omega$$ galvanometer is shunted by a resistance of 8 $$\Omega$$. The percentage of the total current which passes through the galvanometer is :
A
0.1%
B
10%
C
25%
D
0.25%
4
JEE Main 2022 (Online) 26th June Evening Shift
MCQ (Single Correct Answer)
+4
-1
The equivalent resistance between points A and B in the given network is :
A
65$$\Omega$$
B
20$$\Omega$$
C
5$$\Omega$$
D
2$$\Omega$$
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© ExamGOAL 2023 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8652421236038208, "perplexity": 4868.16800470537}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296948871.42/warc/CC-MAIN-20230328201715-20230328231715-00563.warc.gz"} |
http://mathhelpforum.com/calculus/189403-parametrization-intersection.html | # Math Help - Parametrization of Intersection.
1. ## Parametrization of Intersection.
Have no idea how to solve this problem.
Problem:
Parameterize the curve of the intersection of the surfaces $x^2+y^2=9$ and z=x+2y the point (3,0,3) should correspond to the point t=0.
The first equation is a circle of radius 3. So I know that paramterization should be
x=3sin(t*pi)
y=3cos(t*pi)
No idea how to solve for the intersection of the two though.
2. ## Re: Parametrization of Intersection.
Originally Posted by Bracketology
Have no idea how to solve this problem.
Problem:
Parameterize the curve of the intersection of the surfaces $x^2+y^2=9$ and z=x+2y the point (3,0,3) should correspond to the point t=0.
The first equation is a circle of radius 3. So I know that paramterization should be
x=3sin(t*pi)
y=3cos(t*pi)
No idea how to solve for the intersection of the two though.
Since the point (3,0,3) should correspond to the point t=0, it should be
x=3cos(t*pi)
y=3sin(t*pi)
in which case
z=3cos(t*pi) + 6sin(t*pi)
and that's the answer. Think about it.
3. ## Re: Parametrization of Intersection.
Originally Posted by mr fantastic
Since the point (3,0,3) should correspond to the point t=0, it should be
x=3cos(t*pi)
y=3sin(t*pi)
in which case
z=3cos(t*pi) + 6sin(t*pi)
and that's the answer. Think about it.
That's it? Seems simple. I just haven't gotten the hang of parametrics yet. Luckily its another 6 weeks before our next test, so that gives me plenty time to learn. Thanks for the help! | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 2, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9215622544288635, "perplexity": 983.3357196862872}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-30/segments/1469257824395.52/warc/CC-MAIN-20160723071024-00281-ip-10-185-27-174.ec2.internal.warc.gz"} |
http://math.stackexchange.com/questions/182869/finding-volume-and-centroid | # Finding volume and centroid
Find the volume and centroid of the solid that lies in the intersection of the infinite cone $z=\sqrt{x^2 + y^2}$ and the sphere $x^2 + y^2 + z^2 = 1$. Choose an appropriate coordinate system.
So the second eqn is a perfect sphere with radius one. And since its volume I will probably need a triple integral... but im having a hard time find out what to integrate since I have 2 eqns :s
Also for the coordinate system, im thinking something like spherical?
-
You should use spherical coordinates, the cone $z = \sqrt{x^2 + y^2}$ looks like this
therefore the volume is only bounded by the top half of the sphere. From an orthographic view you can imagine the volume to look like an ice cream cone with the bottom of the cone at the origin. The cone will intersect the sphere and cast a circle as a projection in the $xy$ plane. To find the $z$ plane of intersection equate the two equations. Your row will be bounded between $0$ and the radius of sphere. Phi will be bounded between $0$ and $\pi/6$ I believe ( you can find phi yourself once you find the $z$ plane through which the cone intersects the sphere). You theta will have bounds $0 ... 2\pi$.
$\rho$ = rho, not row. We don't really need the z-plane of intersection if the spherical coordinates are to be used. The bound on $\phi$ is best found by equating $\rho\cos\phi$ (which is $z$) to $\rho\sin\phi$ (which is $\sqrt{x^2+y^2}$). – user31373 Aug 17 '12 at 1:48 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8855342864990234, "perplexity": 227.81251412693675}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-15/segments/1398223206120.9/warc/CC-MAIN-20140423032006-00150-ip-10-147-4-33.ec2.internal.warc.gz"} |
https://www.r-bloggers.com/2009/12/rcpp-0-7-0/ | Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.
A new release of Rcpp awaits inclusion on CRAN and has also been sent as a .deb to Debian. It will hit mirrors over the next few days, in the meantime you can get it here as well.
This release has a couple new features :
• inline support: the cfunction from Oleg Sklyar’s excellent inline package has been imported and adapted. This means simple C++ programs can be defined in an R character vector and passed to cfunction which will create a complete file that it then compiles, links and loads — giving you access to compiled C++ code right from the R prompt without having to worry about compiler flags, linker options, … Better still, we extended this to not only support Rcpp but any external library via addtional header / linker arguments that will be passed to R via the PKG_CPPFLAGS, PKG_CXXFLAGS and PKG_LIBS environment variables.
• this even works on Windoze (if you have the Rtools installed as detailed in the Windows Toolset appendix to the R Installation manual) in exactly the same way. And no folks, that still does NOT mean you can use Visual Whatever — R really requires MinGW as the links in this parapgraph document very plainly. But if and when you have the tools, R’s remarkable consistency across operating systems allows you to use Rcpp and inline in pretty much the same way.
• A handful of new examples for the inline support have been added.
• A new type RcppSexp for simple int, double or std::string scalars as well as vectors; this is particularly useful for the inline support.
• This also completes the source code reorginsation: every class now has its own header and implementation file
• Last but not least, the package has been relicensed from LGPL-2.1 (or later) to GPL 2 (or later).
Fuller details are in the ChangeLog on Rcpp page. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.383232444524765, "perplexity": 2769.645138945031}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-49/segments/1637964359976.94/warc/CC-MAIN-20211201083001-20211201113001-00335.warc.gz"} |
http://www.reference.com/browse/more%20incandescent | Definitions
# Christmas lights
Christmas lights (also sometimes called fairy lights, twinkle lights or holiday lights in the United States) are strands of electric lights used to decorate homes, public/commercial buildings and Christmas trees during the Christmas season. Christmas lights come in a dazzling array of configurations and colors. The small "midget" bulbs commonly known as fairy lights are also called Italian lights in some parts of the U.S., such as Chicago.
## History
The first known electrically illuminated Christmas tree was the creation of Edward H. Johnson, an associate of inventor Thomas Edison. While he was vice president of the Edison Electric Light Company, a predecessor of today's Con Edison electric utility, he had Christmas tree light bulbs especially made for him. He proudly displayed his Christmas tree, which was hand-wired with 80 red, white and blue electric incandescent light bulbs the size of walnuts, on December 22, 1882 at his home on Fifth Avenue in New York City. Local newspapers ignored the story, seeing it as a publicity stunt. However, it was published by a Detroit newspaper reporter, and Johnson has become widely regarded as the Father of Electric Christmas Tree Lights. By 1900, businesses started stringing up Christmas lights behind their windows. Christmas lights were too expensive for the average person; as such, electric Christmas lights did not become the majority replacement for candles until 1930.
In 1895, U.S. President Grover Cleveland proudly sponsored the first electrically lit Christmas tree in the White House. It was a huge specimen, featuring more than a hundred multicolored lights. The first commercially produced Christmas tree lamps were manufactured in strings of multiples of eight sockets by the General Electric Co. of Harrison, New Jersey. Each socket took a miniature two-candela carbon-filament lamp.
From that point on, electrically illuminated Christmas trees, but only indoors, grew with mounting enthusiasm in the United States and elsewhere. San Diego in 1904 and New York City in 1912 were the first recorded instances of the use of Christmas lights outside. McAdenville North Carolina claims to have been the first in 1956. The Library of Congress credits the town for inventing "the tradition of decorating evergreen trees with Christmas lights dates back to 1956 when the McAdenville Men's Club conceived of the idea of decorating a few trees around the McAdenville Community Center. However, the Rockefeller Center Christmas Tree has had "lights" since 1931, but did not have real electric lights until 1956. Furthermore, Philadelphia's Christmas Light Show and Disney's Christmas Tree also began in 1956. Though General Electric sponsored community lighting competitions during the 1920s, it would take until the mid 1950s for the use of such lights to be adopted by average households.
Over a period of time, strings of Christmas lights found their way into use in places other than Christmas trees. Soon, strings of lights adorned mantles and doorways inside homes, and ran along the rafters, roof lines, and porch railings of homes and businesses. In recent times, many city skyscrapers are decorated with long mostly-vertical strings of a common theme, and are activated simultaneously in Grand Illumination ceremonies.
In the mid 2000s, the video of the home of Carson Williams was widely distributed on the internet as a viral video. It garnered national attention in 2005 from The Today Show on NBC, Inside Edition and the CBS Evening News and was featured in a Miller television commercial. Williams turned his hobby into a commercial venture, and was commissioned to scale up his vision to a scale of 250,000 lights at a Denver shopping center, as well as displays in parks and zoos.
## Technology
### Types of Christmas lights
The types of lamps used in Christmas lighting sets may be based on a variety of technologies. Common lamp types are incandescent light bulbs and now light-emitting diodes (LEDs). Less common are neon lamp sets. Fluorescent lamp sets were produced for a limited time by Sylvania in the mid-1940s.
#### Incandescent
Incandescent lights, the type most commonly used in Christmas lights, produce a broad-spectrum white light, and are colored by coating the glass envelope with a transparent or translucent paint which acts as a color filter. Some early Japanese-made lamps, however, used colored glass. Though less expensive, the painted lamps suffer from fading or flaking of the paint when exposed to weather. Older bulbs were also coated on the insides of the bulbs to prevent this effect, but were more costly to manufacture.
#### LEDs
Light-emitting diode (LED) Christmas lights are quickly gaining popularity in many places due to their low energy usage (about one tenth the energy used by incandescent bulbs), very long lifetimes, and associated low maintenance. Colored LEDs are also far more efficient at producing light than their colored incandescent counterparts.
There are two types of LEDs: colored LEDs and white LEDs. Colored LEDs emit a specific color light (monochromatic light), regardless of the color of the transparent plastic lens that encases the LED's chip. The plastic may be colored for cosmetic reasons, but does not substantially affect the color of the light emitted. Because the light is determined by the LED's chip rather than the plastic lens, Christmas lights of this type do not suffer from color fading. In addition, the plastic lens is much more durable than the glass envelope of incandescent bulbs.
White LEDs are similar to colored LEDs in most respects such as power and durability, but utilize a two-stage process to create the white (polychromatic, or broad spectrum) light. In the first stage, the LED actually only produces one color of light, similar to any other LED. In the second stage, some of the blue or violet-blue is absorbed by a phosphor which fluoresces yellow, imitating the broad spectrum of colors which our eyes perceive as "white". This is essentially the same process used in fluorescent lamps, except for the use of an LED to create blue light rather than excited gas plasma to create ultraviolet.
White LEDs can be used as white Christmas lights, or can be used to create any other color through the use of colored refractors and lenses, similar to the more commonly used incandescent bulbs. Color fading may therefore occur due to the exposure of colored plastics to sunlight or heat, as with ordinary Christmas lights. Yellowing may also occur in the epoxy "bulb" in which the LED is encased if left in the sun consistently.
LEDs use much less electricity (only 4 watts for a 70-light string) and have a much greater lifespan than incandescent lamps. Since they are constructed from solid state materials and have no metallic filaments to burn out or break, LEDs are also much less susceptible to breakage from impact or rough handling.
Although LEDs themselves are long-life devices, older or lower-quality strands of LED-based Christmas lights can suffer from early failure. This is particularly so with blue ones, which are the newest and most expensive, and therefore prone to cost-cutting; in addition, spares are rarely included with sets. Most LED-based Christmas lights use copper wire which connects to the aluminum-based wires of the LEDs. Exposing this combination of metals to moisture can result in galvanic corrosion inside of the lamps' sockets, causing them to stop working. Many other sets use cheaper steel leads on the LEDs, which instead rust, leading to the same result. Some newer and higher-quality sets of LED Christmas lights have each LED permanently mounted in a non-removable weathertight base to keep out rain and other moisture, helping to prevent such corrosion; however, this prevents the user from replacing defective bulbs.
Most common consumer LED lamps produce intense, deep, pure colours, versus incandescent bulbs which generally have subtler, yellow-tinted colours, often somewhat faded especially if used outside. Blue tends to be the dimmest incandescent color, but the brightest in LED, while yellow is just the opposite. Very early strings of LED lights were noticeably dimmer than incandescent bulbs, but now are often noticeably brighter. These factors combine to give LED lamps a distinct aesthetic from older incandescent strings, although white LEDs behind coloured lenses do offer the ability to provide a more incandescent-type appearance with most of the benefits of energy efficiency. However, most use coloured-chip type LEDs that produce the intense colours. This is largely due to the maturity of coloured LED versus newer white LED technology, and as the technology improves so will the ability to change the aesthetics of the lamps, at lower cost than at present. As of 2007, "warm white" LED sets are common for the first time in U.S. stores, having a color similar to a compact fluorescent light. However, this color needs to be more of an orange tint to match the color of such small bulbs, because they burn at a lower temperature. Still, this is a significant improvement from the very cold-white (and often irregularly-tinted) color of early white sets.
Additionally, low-end sets do not contain power supplies (or have only a transformer instead of a SELV), and so the bulbs flicker in sync with the alternating current, being completely off when the voltage is negative. This produces a noticeable stroboscopic effect when an individual happens to move the lights across his or her field of view quickly, as when moving the eyes or turning the head rapidly. Higher-quality strings include a bridge rectifier to supply full-wave direct current to the lamps, making the lights brighter and greatly reducing the flickering (though there is still a small amount because diodes need a minimum voltage to begin conducting). Cheaper sets with two circuits connect each in the opposite polarity, which minimizes flicker in the combined light reflected from walls, and also keeps power consumption symmetrical so as not to affect the electrical system.
Many mini sets use standard 3 mm dome-shaped LEDs, and have a plastic cover over them to provide refraction, which is an important step in diffusing the unidirectional light they cast. These covers come in C5, C6, and C7 sizes (⅝, ¾, and ⅞-inch, or 16, 19, and 22 mm diameters, respectively) pointed "strawberries," G12 (12mm or almost ½-inch) globe "raspberries," and "M5" (5mm or -inch) pointed cylinders, equivalent to the T1¾ mini lights so common since the 1980s. For blue and green, these covers may have some fluorescence, leading to a lighter color. Other sets have 5 mm domes with no covers, though because these project light in one direction, many of these instead have a cone-shaped indentation on the top, refracting much of the light out to the sides. Still other sets have covers like snowflakes (or for Halloween, pumpkins). There are also multi-LED screw-in bulbs which replace real C7½ and C9¼ bulbs, and are much closer in brightness than the mini imitations.
#### Fiber optic lights
Fiber optic technology is also used in Christmas lighting, especially by incorporating it into artificial Christmas trees. Incandescent lamps or LEDs are located in the tree base and many optic fibers extend from the lamps to the ends of the tree branches. These devices frequently use a step-down transformer, because they have only one or two lamps or LEDs.
#### Bubble Lights
Bubble lights are a type of incandescent novelty light that acquired some popularity during the 1950s. Their main feature is a sealed glass tube with a colored bubbling liquid inside. While the idea was first demonstrated by Benjamin Franklin, the idea was adapted for use in Christmas Lights. They were invented by Carl Otis in 1935, who then sold the patents to the NOMA Electric Corporation. There is a long story involving patent fights. Bubble Lights can still be purchased online and in stores to this day.
#### Light sculptures
Lights are sometimes mounted on frames -- typically metal for large lights and plastic for miniature ones. These were first used for public displays on lampposts, street lights, and telephone poles in cities and towns. For public displays large C7 bulbs are generally used, but by the 1990s light sculptures were being made in smaller form with miniature lights for home use. Consumer types now tend to come with a plastic sheet backing printed in the proper design, and in the 2000s now with nearly photographic quality graphics and usually on a holographic "laser" backing. Public displays on often have outdoor-rated garland on the frame as well, making them very decorative even in the daytime. Places where notable displays of light sculptures may be seen include Gatlinburg and Pigeon Forge in Tennessee.
#### Ornamentation
Early bulbs were sometimes made in shapes and painted, the same way that glass ornaments are. These are typically pressed glass, much as common dishware was at the time. These are reproduced in very limited quantity nowadays, typically found only at specialty retailers and online. Metal reflectors were also used until the 1970s, having a center hub of cardboard, which then had tabs that pressed between the bulb and the socket.
Miniature lights sets can come with attached ornaments, typically plastic but sometimes glass. These began mid-century with petal "reflectors" which actually refracted the light and focused it in beams, and perhaps even earlier with crystal-like ones. On both types, the bulb stuck out of the center, and the "reflector" could be removed from the socket. Later designs, though much less popular, included stars. LED lights now come molded into shapes, though the light comes from the top instead of the center.
Mini lights can also have full-size ornaments normally sold on sets of ten. Certain sets have more than one bulb per ornament, such as for snowmen and candy canes which are long. There is an enormous array of other designs, ranging from holly berries and poinsettias to star-shaped santas and wire mesh snowflakes. There are also ones for other holidays.
### Sizes
Note that the following may be particular to North America, and may vary in countries with mains other than 120 volts.
Christmas lighting began with small C6 bulbs -- C meaning "candle" for the flame shape, and 6 meaning inches (¾ in, or 19 mm) in diameter. These were on a miniature candelabra screw-base, now designated E10 (Edison screw, 10 mm). Replicas of these bulbs are now produced as miniature strings, usually with the entire bulb replaced, but sometimes as a decorative cover with regular bulbs inside. These bulbs tend to be transparent white or colors, and are often ornately designed with crystal-like patterns.
Later bulbs were called C7½, being $tfrac\left\{7frac\left\{1\right\}\left\{2\right\}\right\}\left\{8\right\}$ inches ( in, or 24 mm) in diameter; however, these have a blunt shape (and should therefore be called B7½, or B24). Mixing metric and English units, there are also now G30 globes which are 30 mm ( in, or G9½) in diameter that uses these sockets. These are still used for the classic or even retro look, and use about five watts each. Older bulbs drew 7½ watts of power, and were reduced to save power. Early bulbs, as well as some new antique reproductions, are made in various shapes and then painted like Christmas ornaments. Bubble lights and twinkle bulbs also come in this size.
Outdoor-only bulbs are designated C9¼ ( in, or 29 mm), and have a similar blunt shape as the C7½, but an E17 "intermediate" base. Some modern versions of these strings are now listed for indoor and outdoor use. These bulbs are rated at about seven watts each, and also now come in a globe shape, designated G40 (40 mm, or in). Some of the blunt-shape bulbs now come painted with designs, or swirled in more than one color. It is now very difficult to find twinkle bulbs in this size.
Standard mini bulbs are T1¾, indicating that they are a tube shape inches (5.5 mm) in diameter. Larger mini bulbs, which began appearing around 2004, are about twice this size, but are still very uncommon. Both types, along with most of the candle-shaped ones, are pinched-off at the tip rather than the base during manufacturing. Most contemporary miniature light bulbs have an internal shunt that is intended to activate when the bulb's filament burns out. The shunt closes the circuit across the bad filament, restoring continuity and illuminating the rest of the string. However, if one shunt fails to close properly, the whole string will fail to light. Other miniature types include globe-shaped "pearl" and smaller "button" lights, which are often painted in translucent or pearlescent colors. "Rice" lights are tiny, like a grain of rice, and can even have a subminiature base, if they are not already fixed permanently to the wires (on low-voltage sets). Rice lights are typically transparent, although colored variations do exist. They are intended to create tiny points of light, and are suitable for decorating miniature models, small wreaths, and for other similar situations in which even "midget" T1¾ lights may be too large.
LED lights, which are encased in solid plastic rather than a hollow glass bulb, may be molded into any shape. Because of the way the LED casts light in only one direction, this is the most common way to design LED lighting, with even "plain" sets having some sort of crystal pattern to create refraction.
Many bargain brands have dome-shaped LEDs which focuses the light to where it is sharply visible when viewed head-on, but almost invisible from a perpendicular viewpoint. This has both advantages and disadvantages according to one's decorating needs.
If a small LED bulb size but wider viewing perspective is desired, wide-angle LEDs are available. Rather than being dome-shaped (convex), the envelope is concave (sunken in) to cause wider distribution of light.
All miniature bulbs (including some LED sets) have a wedge base, though the exact design of each is inconsistent, making it somewhat difficult for the average consumer to change bulbs. To replace a bulb, the plastic base of the bulb must usually be changed by straightening the two wires and pulling the glass part out. Most replacement bulbs do not even include the bases anymore, despite getting only ten in a package and being charged nearly half what an entirely new string of 100 costs. For this reason, many Americans treat mini Christmas lights as being disposable, in addition to colored lights tending to fade even with only brief exposure to weathering. Many LED sets are coming permanently wired, with bases that look like conventional pull-out bulbs.
### Light sets
Traditional C6 bulbs were typically 15 Volts, and used in series strings of eight bulbs, or multiples of 8. The use of eight bulbs (120 Volts/8 lamps = 15 Volts per lamp) gives each lamp the rated voltage for proper brightness. Later sets used nine bulbs on a string to increase the life of the bulbs by reducing the voltage each lamp received (120 Volts / 9 lamps = 13.33 Volts per bulb) but not significantly reducing the light output of the bulbs.
Large C7½ and C9¼ bulbs typically come in sets of 25, though bubble lights come in sets of seven, and some non-holiday sets come in ten or twelve. Sockets are usually spaced about one foot or 30 cm apart, and are clamped to the wire with an integrated insulation-piercing connector. Some older parallel sets had 15 bulbs, as do some of the newer globe sets manufactured today. Both of these bulbs are designed to run on 120 volts and the light sets that use them are parallel wired.
Miniatures first came in sets of 35 (3.5 volts per bulb), and sometimes smaller sets of 20 (6 volts per bulb). Sets of ten (12 volts per bulbs) were made for very small trees, but are quite hot, and are now usually used for tree toppers only. This number is convenient for stars, which have a total of ten points (five outward and five inward), and often have another light in the middle, occasionally on both sides.
Incandescent miniatures now usually come in sets of 50 or 100 (which contains two circuits of 50), though decorative sets with larger bulbs (C6 or pearl style) typically come in 35 or 70. Several "extra-bright" sets also use 70 or 105 bulbs, keeping the per-bulb voltage at 3.5 instead of 2.5.
LED sets can vary greatly. Common is a set of 60 (2 volts per bulb), but white LED sets use two circuits of 30 (4 volts per bulb). Multicolor sets may have special wiring, because red and yellow require less voltage than the newer blue-based ones (blue, emerald green and fluorescent white), but typically come in sets with a multiple of 35.
Battery-powered sets typically come in 10 or 12, and can use standard 2.5 to 3.5-volt bulbs because they run two batteries, totaling three volts or less. LEDs are becoming increasingly common as they greatly prolong battery life, but because they also last longer they are often soldered directly to the wires, making up for some of the increased cost of the newer LEDs. 'Rice lights" are often made this way as well, and likewise may also have more bulbs per set as they draw somewhat less power per bulb than other incandescents.
### Control technology
Christmas lights can be animated using special "flasher" or "interrupter" bulbs or by electronic controller. Flasher bulbs use a bi-metallic strip which interrupts the series circuit when the lamp becomes hot. An electronic Christmas light controller usually has a diode bridge followed by a resistor-based voltage divider, a filter capacitor and a fixed-program microcontroller. The micro-controller has three or four outputs which are connected to transistors or thyristor which control interleaved circuits, each with lamps of a single color.
Controllers can be set up to change flashing or animation styles by pressing a button or turning a dial on the unit; others have only one pattern, but the speed of this pattern can usually be adjusted by turning a similar dial.
Most multi-function sets feature 8 to 16 moving light functions. Some very common functions are fading and chasing. More extravagant and less common functions are stepping on and 2-channel flashing. These lights usually come in sets of 140 or 150. This is because to give the chasing effect, bulbs must be arranged in 4 circuits of 35 (equals 140) or 3 circuits of 50 (equals 150). These light sets use even less power than a regular set of 150 because the lights are not always on, and therefore the bulbs do not get as hot.
Usually, computerized sets cannot be connected end-to-end. However, some newer sets contain special miniature plugs - a "female" plug is located at the end of the set, and a "male" plug is located between the control box and the beginning of the actual lights. By disconnecting the control box from one set, it can now be plugged into the end of an identical chasing set to produce a longer strand of chasing lights. These plugs generally have a twist-on locking feature similar to that found on garden hoses.
Fiber-optic Christmas lighting can also be animated electronically, particularly when the set incorporates LEDs. When an incandescent lamp is used, animation can created by means of a rotating color wheel.
There's a new control technology being developed in Ottawa, Canada Lights On Calico which enables multiple homes to link up over the Internet in-real time and in-synch. A central website initiates the timing using Network Time Protocol to keep the local computers in synch, and each location has a small Java program that controls a device which interfaces with the USB port to which your Christmas lights plug into. In this way, anyone online can "plug in" to this network and at their discretion working independently or in-synch engage their Christmas Light display on a global level.
### Power considerations
Incandescent (midget) or LED-based sets usually have each lamp connected in series to be powered without a transformer in the set. Screw-base C7 and C9 light sets use line voltage (120 volt) bulbs and are wired in parallel. LED-based sets use a current-limiting resistor to reduce the current supplied to each LED. Neon-lamp-based sets have lamps connected in parallel, each with its own current-limiting resistor. Battery-powered sets are also wired in parallel.
Some incandescent or LED-based strings use a power supply transformer with lamps connected in parallel. These sets are much safer, but there is a voltage drop at the end of the string causing reduced brightness of the lamps at the end of the set. The reduced brightness is, however, less noticeable with LED-based sets than incandescent sets. Power supplies with integrated plugs may make the set difficult to connect in certain places.
A line-operated AC string with a male plug on one end and a female socket on the other end can be conveniently connected end-to-end with other similar strings. The gauge of wire used and the power consumption of each string will determine how many strings can be safely daisy-chained this way, or whether the end string will have diminished voltage and brightness.
### Troubleshooting
Individual bulbs fail either open or shorted. In a series string, when a bulb fails open, the whole string goes out, unless there is a special feature included to bridge the open bulb. Typical incandescent strings in the 1950s - 1960s were wired in series and frequently burnt out.
For a series string, fixing failures requires a tedious process: each bulb is replaced with a known good bulb, hunting for the broken one by trial-and-error. If more than one bulb is broken, then each bulb in the broken string needs to be tested in a known-good string. Sometimes a bulb will not actually break, but will come loose in its socket. Its connection can also become corroded. Those two problems can be fixed by resetting each bulb in turn.
In a parallel string, one shorted bulb makes the whole string fail, requiring a similar troubleshooting process. However, the shorted string must be protected by a current limiting device, which may require resetting in between tests.
Fiber optic sets are the simplest to troubleshoot, since they contain only a few light sources, sometimes only one or two, and the place of failure can be located very quickly. Units containing color wheels may also require maintenance of mechanical parts.
### Safety
Any set should be unplugged before repairing. If a set has no transformer, it is not line isolated. The small matchbox-sized electronic controllers do not have transformers in them, and sets with such controllers are also not line isolated, as well as all parts inside the controllers.
The number of strands of continuous light sets that may be safely conjoined varies based on whether the lights are LEDs, ordinary miniature light bulbs, or the larger C7/C9 type light bulbs. Other factors include the voltage of the set and the size of the wiring in the set. Those with questions should consult the manufacturer's instructions or an electrician.
Most light sets come with built in fuses to help protect against overheating and to prevent household fuses or circuit breakers from being tripped. If a fuse blows, the strand must be unplugged and the number of lights must be reduced. If the strand has nothing attached, or has blown repeatedly, it may contain a short circuit and should be discarded.
Hobbyists who don't want to pollute the environment by discarding a damaged set can cut it into many individual bulbs, each of which can be powered by a safe low voltage source. These bulbs can be used in projects such as microcontroller or PC controlled animated displays. The plug of the damaged set should, however, be destroyed and discarded for safety reasons, but this produces much less waste than discarding the whole set.
Some fiber optic sets may use halogen bulbs in their bases, in such cases, all precautions related to this type of bulbs should be observed.
Animated sets should not be watched by people having photosensitive epilepsy. Non-animated sets exist and can be used in such cases.
Many light sets may contain traces of lead in their PVC insulation, and consumers should wash hands thoroughly after handling these products, especially before eating. Proposition 65 of California requires that if products contain lead or traces of lead then a warning must be printed on packing of products. One must be sure to check the label for this and any additional warnings. The purpose of the lead in the PVC insulation is to make the PVC fire retardant, and to protect the PVC from ozone and other airborne pollutants which can crack and degrade the PVC over time.
An episode of the show MythBusters covered the possible fire danger from Christmas lights.
## Outdoor displays
### Public venues
Displays of Christmas lights in public venues and on public buildings are a popular part of the annual celebration of Christmas, and may be set up by businesses or by local governments. The displays utilise Christmas lights in many ways, including decking towering Christmas trees in public squares, street trees and park trees, adorning lampposts and other such structures, decorating significant buildings such as town halls and department stores, and lighting up popular tourist attractions such as the Eiffel Tower and the Sydney Opera House.
Annual displays in Oxford Street, London, England are adored by the public and local businesses alike, have been erected for decades, assisted by companies like Piggotts
### Neighborhoods
In the U.S. from the 1960s, beginning in tract housing, it became increasingly the custom to completely outline the house (but particularly the eaves) with weatherproof Christmas lights. The Holiday Trail of Lights is a joint effort by cities in east Texas and northwest Louisiana that had its origins in the Festival of Lights and Christmas Festival in Natchitoches, started in 1927, making it one of the oldest light festivals in the United States.
It is often a pastime to drive or walk around neighborhoods in the evening to see the lights displayed on and around other homes. While some homes have no lights, others may have incredibly ornate displays which require weeks to construct. A rare few have even made it to the Extreme Christmas TV specials shown on HGTV, at least one requiring a generator and another requiring separate electrical service to supply the amount of electrical power required.
In 1986, Barry "Mad Dog" Gottlieb, organized the "Tacky Xmas Decoration Contest and Grand Highly Illuminated House Tour" with a tour of decorated homes in Richmond, Virginia. Since then, people either sign up for a tour, or drive around to find houses that are the tackiest. Most of the houses on this tour are completely covered in Christmas lights, similar to the way Clark Griswold decorated his house in the movie Christmas Vacation. The tour has been featured on "NPR", "Great Things About the Holidays on Bravo, "Crazy Christmas Lights" on TLC, and HGTV among other nationally broadcast programs. Locals in Richmond refer to it as the " Tacky Light Tour" and a growing number of cities have adopted this family Christmas tradition.
In Australia and New Zealand, chains of Christmas lights were quickly adopted as an effective way to provide ambient lighting to verandas, where cold beer is often served in the long hot summer evenings. For many years the use of Christmas lights on Australian homes was mainly limited to this simple form. In the last decade increasingly elaborate Christmas lights have been displayed and driving around between 8.00 and 10.00pm to look at the lights has become a popular family entertainment. While in some areas there is fierce competition, with Town Councils offering awards for the best decorated house, in other areas it is seen as a co-operative effort, with residents priding themselves on their street or their neighbourhood.
## Other holidays
In the United States, lights have been produced for many other holidays. These may be simple sets in typical holiday colors, or the type with plastic ornaments which the light socket fits into. Light sculptures are also produced in typical holiday icons.
Halloween is the most popular, with miniature light strings having black-insulated wires and semi-opaque orange bulbs. Later sets had some transparent purple bulbs (a representation of black, similar to blacklight), a few even have transparent green, or a translucent or semi-opaque lime green (possibly representing slime as in Ghostbusters, or creatures like goblins or space aliens). Two types of icicle lights are sold at Halloween: all-orange, and a combination of purple and green known as "slime lights."
Easter lights are often produced in pastels. These typically have white wire and connectors.
Red, white, and blue lights are produced for Independence Day, as well as U.S. flag and other patriotic-themed ornaments. Net lights have been produced with the lights in a U.S. flag pattern. In 2006 some stores carried stakes with LEDs that light fiber-optics, looking similar to fireworks.
These above light strings are occasionally used on Christmas Trees anyway, usually to add extra variety to the colors of the lights on the tree.
Various types of patio lighting with no holiday theme are also made for summertime. These are often clear white lights, but most are ornament sets, such as lanterns made of metal or bamboo, or plastic ornaments in the shape of barbecue condiments, flamingos and palm trees, or even various beers. Some are made of decorative wire or mesh, in abstract shapes such as dragonflies, often with glass "gems" or marbles. Light sculptures are also made in everything from wire-mesh frogs to artificial palm trees outlined in rope lights. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 1, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.27496063709259033, "perplexity": 3164.4521481977717}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-14/segments/1427131297505.18/warc/CC-MAIN-20150323172137-00069-ip-10-168-14-71.ec2.internal.warc.gz"} |
https://www.texasgateway.org/resource/43-binomial-distribution-optional?book=297701&binder_id=297646 | Introduction
Introduction
There are three characteristics of a binomial experiment:
1. There are a fixed number of trials. Think of trials as repetitions of an experiment. The letter n denotes the number of trials.
2. There are only two possible outcomes, called success and failure, for each trial. The outcome that we are measuring is defined as a success, while the other outcome is defined as a failure. The letter p denotes the probability of a success on one trial, and q denotes the probability of a failure on one trial. p + q = 1.
3. The n trials are independent and are repeated using identical conditions. Because the n trials are independent, the outcome of one trial does not help in predicting the outcome of another trial. Another way of saying this is that for each individual trial, the probability, p, of a success and probability, q, of a failure remain the same. Let us look at several examples of a binomial experiment.
Example 1: Toss a fair coin once and record the result.
This is a binomial experiment since it meets all three characteristics. The number of trials n = 1. There are only two outcomes, a head or a tail, of each trial. We can define a head as a success if we are measuring number of heads. For a fair coin, the probabilities of getting a head or a tail are both .5. So, p = q − .5. Both p and q remain the same from trial to trial. This experiment is also called a Bernoulli trial, named after Jacob Bernoulli who, in the late 1600s, studied such trials extensively. Any experiment that has characteristics two and three and where n = 1 is called a Bernoulli trial. A binomial experiment takes place when the number of successes is counted in one or more Bernoulli trials.
Example 2: Randomly guess the answer to a multiple choice question that has four options to choose from.
This is a binomial experiment since it meets all three characteristics. The number of trials n = 1. There are only two outcomes, guess correctly or guess wrong, of each trial. We can define guess correctly as a success. For a random guess (you have no clue at all), the probability of guessing correct should be $1414$ because there are four options and only one option is correct. So, and $q=1−p=1−14=34q=1−p=1−14=34$. Both p and q remain the same from trial to trial. This experiment is also a Bernoulli trial. It meets the characteristics two and three and n = 1.
Example 3: Toss a fair coin five times and record the result.
This is a binomial experiment since it meets all three characteristics. The number of trials n = 5. There are only two outcomes, a head or a tail, of each trial. If we define a head as a success, then p = q = 0.5. Both p and q remain the same for each trial. Since n = 5, this experiment is not a Bernoulli trial although it meets the characteristics two and three.
Example 4: Randomly guess 10 multiple choice questions in an exam. Each question has four options.
This is a binomial experiment since it meets all three characteristics. The number of trials n = 10. There are only two outcomes, guess correctly or guess wrong, of each trial. We can define guess correctly as a success. As we explained in example 2, $p=14p=14$ and $q=1−p=1−14=34q=1−p=1−14=34$. Both p and q remain the same for each guess. Since n = 10, this experiment is not a Bernoulli trial.
The next two experiments are not binomial experiments.
Example 5: Randomly select two balls from a jar with five red balls and five blue balls without replacement. This means we select the first ball, and then without returning the selected ball into the jar, we will select the second ball.
This is not a binomial experiment since the third characteristic is not met. The number of trials n = 2. There are only two outcomes, a red ball or a blue ball, of each trial. If we define selecting a red ball as a success, then selecting a blue ball is a failure. The probability of getting the first ball red is $510510$ since there are five red balls out of 10 balls. So, $p=510p=510$ and . However, p and q do not remain the same for the second trial. If the first ball selected is red, then the probability of getting the second ball red is $4949$ since there are only four red balls out of nine balls. But if the first ball selected is blue, then the probability of getting the second ball red is $5959$ since there are still five red balls out of nine balls.
Example 6: Toss a fair coin until a head appears.
This is not a binomial experiment since the first characteristic is not met. The number of trials n is not fixed. n could be 1 if a head appears from the first toss. n could be 2 if the first toss is a tail and the second toss is a head. So on and so forth.
More examples of binomial and non-binomial experiments will be discussed in this section later.
The outcomes of a binomial experiment fit a binomial probability distribution. The random variable X = the number of successes obtained in the n independent trials.
There are shortcut formulas for calculating mean μ, variance σ2, and standard deviation σ of a binomial probability distribution. The formulas are given as below. The deriving of these formulas will not be discussed in this book.
$μ=np,σ2=npq,σ=npq.μ=np,σ2=npq,σ=npq.$
Here n is the number of trials, p is the probability of a success, and q is the probability of a failure.
Example 4.8
At ABC High School, the withdrawal rate from an elementary physics course is 30 percent for any given term. This implies that, for any given term, 70 percent of the students stay in the class for the entire term. The random variable X = the number of students who withdraw from the randomly selected elementary physics class. Since we are measuring the number of students who withdrew, a success is defined as an individual who withdrew.
Try It 4.8
The state health board is concerned about the amount of fruit available in school lunches. Forty-eight percent of schools in the state offer fruit in their lunches every day. This implies that 52 percent do not. What would a success be in this case?
Example 4.9
Suppose you play a game that you can only either win or lose. The probability that you win any game is 55 percent, and the probability that you lose is 45 percent. Each game you play is independent. If you play the game 20 times, write the function that describes the probability that you win 15 of the 20 times. Here, if you define X as the number of wins, then X takes on the values 0, 1, 2, 3, . . ., 20. The probability of a success is p = 0.55. The probability of a failure is q = .45. The number of trials is n = 20. The probability question can be stated mathematically as P(x = 15). If you define X as the number of losses, then a success is defined as a loss and a failure is defined as a win. A success does not necessarily represent a good outcome. It is simply the outcome that you are measuring. X still takes on the values of 0, 1, 2, 3, . . ., 20. The probability of a success is $p=.45p=.45$. The probability of a failure is $q=.55q=.55$.
Try It 4.9
A trainer is teaching a dolphin to do tricks. The probability that the dolphin successfully performs the trick is 35 percent, and the probability that the dolphin does not successfully perform the trick is 65 percent. Out of 20 attempts, you want to find the probability that the dolphin succeeds 12 times. State the probability question mathematically.
Example 4.10
A fair coin is flipped 15 times. Each flip is independent. What is the probability of getting more than 10 heads? Let X = the number of heads in 15 flips of the fair coin. X takes on the values 0, 1, 2, 3, ..., 15. Since the coin is fair, p = .5 and q = .5. The number of trials n = 15. State the probability question mathematically.
Solution 4.10
P(x > 10)
Try It 4.10
A fair, six-sided die is rolled 10 times. Each roll is independent. You want to find the probability of rolling a one more than three times. State the probability question mathematically.
Example 4.11
Approximately 70 percent of statistics students do their homework in time for it to be collected and graded. Each student does homework independently. In a statistics class of 50 students, what is the probability that at least 40 will do their homework on time? Students are selected randomly.
a. This is a binomial problem because there is only a success or a ________, there are a fixed number of trials, and the probability of a success is .70 for each trial.
Solution 4.11
a. failure
b. If we are interested in the number of students who do their homework on time, then how do we define X?
Solution 4.11
b. X = the number of statistics students who do their homework on time
c. What values does x take on?
Solution 4.11
c. 0, 1, 2, . . ., 50
d. What is a failure, in words?
Solution 4.11
d. Failure is defined as a student who does not complete his or her homework on time.
The probability of a success is p = .70. The number of trials is n = 50.
e. If p + q = 1, then what is q?
Solution 4.11
e. q = .30
f. The words at least translate as what kind of inequality for the probability question P(x ____ 40)?
Solution 4.11
f. greater than or equal to (≥)
The probability question is P(x ≥ 40).
Try It 4.11
Sixty-five percent of people pass the state driver’s exam on the first try. A group of 50 individuals who have taken the driver’s exam is randomly selected. Give two reasons why this is a binomial problem.
Notation for the Binomial: B = Binomial Probability Distribution Function
Notation for the Binomial: B = Binomial Probability Distribution Function
X ~ B(n, p)
Read this as X is a random variable with a binomial distribution. The parameters are n and p; n = number of trials, p = probability of a success on each trial.
Example 4.12
It has been stated that about 41 percent of adult workers have a high school diploma but do not pursue any further education. If 20 adult workers are randomly selected, find the probability that at most 12 of them have a high school diploma but do not pursue any further education. How many adult workers do you expect to have a high school diploma but do not pursue any further education?
Let X = the number of workers who have a high school diploma but do not pursue any further education.
X takes on the values 0, 1, 2, . . ., 20 where n = 20, p = .41, and q = 1 – .41 = .59. X ~ B(20, .41)
Find P(x ≤ 12). There is a formula to define the probability of a binomial distribution P(x). We can use the formula to find $P(x≤12)P(x≤12)$. But the calculation is tedious and time consuming and, people usually use a graphing calculator, software, or binomial table to get the answer. Use a graphing calculator, you can get $P(x≤12)=.9738P(x≤12)=.9738$. The instruction of TI-83, 83+, 84, 84+ is given below.
Using the TI-83, 83+, 84, 84+ Calculator
Go into 2nd DISTR. The syntax for the instructions are as follows:
To calculate the probability of a value $P(x=value)P(x=value)$: use binompdf(n, p, number). Here binompdf represents binomial probability density function. It is used to find the probability that a binomial random variable is equal to an exact value. n is the number of trials, p is the probability of a success, and number is the value. If number is left out, which means use binompdf(n, p), then all the probabilities $P(x=0),P(x=1),…,P(x=n)P(x=0),P(x=1),…,P(x=n)$ will be calculated.
To calculate the cumulative probability $P(x≤value)P(x≤value)$: use binomcdf(n, p, number). Here binomcdf represents binomial cumulative distribution function. It is used to determine the probability of at most type of problem, the probability that a binomial random variable is less than or equal to a value. n is the number of trials, p is the probability of a success, and number is the value. If number is left out, all the cumulative probabilities $P(x≤0),P(x≤1),…,P(x≤n)P(x≤0),P(x≤1),…,P(x≤n)$ will be calculated.
To calculate the cumulative probability $P(x≥value)P(x≥value)$: use 1 binomcdf(n, p, number). n is the number of trials, p is the probability of a success, and number is the value. TI calculators do not have a built-in function to find the probability that a binomial random variable is greater than a value. However, we can use the fact that $P(x>value)=1−P(x≤value)P(x>value)=1−P(x≤value)$ to find the answer.
For this problem: After you are in 2nd DISTR, arrow down to binomcdf. Press ENTER. Enter 20,.41,12). The result is P(x ≤ 12) = .9738.
NOTE
If you want to find P(x = 12), use the pdf (binompdf). If you want to find P(x > 12), use 1 − binomcdf(20,.41,12).
The probability that at most 12 workers have a high school diploma but do not pursue any further education is .9738.
The graph of X ~ B(20, .41) is as follows:
The previous graph is called a probability distribution histogram. It is made of a series of vertical bars. The x-axis of each bar is the value of X = the number of workers who have only a high school diploma, and the height of that bar is the probability of that value occurring.
The number of adult workers that you expect to have a high school diploma but not pursue any further education is the mean, μ = np = (20)(.41) = 8.2.
The formula for the variance is σ2 = npq. The standard deviation is σ = $npqnpq$.
σ = $(20)(.41)(.59)(20)(.41)(.59)$ = 2.20.
The following is the interpretation of the mean $μ=8.2μ=8.2$ and standard deviation:
If you randomly select 20 adult workers, and do that over and over, you expect around eight adult workers out of 20 to have a high school diploma but do not pursue any further education on average. And you expect that to vary by about two workers on average.
Try It 4.12
About 32 percent of students participate in a community volunteer program outside of school. If 30 students are selected at random, find the probability that at most 14 of them participate in a community volunteer program outside of school. Use the TI-83+ or TI-84 calculator to find the answer.
Example 4.13
A store releases a 560-page art supply catalog. Eight of the pages feature signature artists. Suppose we randomly sample 100 pages. Let X = the number of pages that feature signature artists.
1. What values does x take on?
2. What is the probability distribution? Find the following probabilities:
1. the probability that two pages feature signature artists
2. the probability that at most six pages feature signature artists
3. the probability that more than three pages feature signature artists
3. Using the formulas, calculate the (i) mean and (ii) standard deviation.
Solution 4.13
1. x = 0, 1, 2, 3, 4, 5, 6, 7, 8
2. This is a binomial experiment since all three characteristics are met. Each page is a trial. Since we sample 100 pages, the number of trials is n = 100. For each page, there are two possible outcomes, features signature artists or does not feature signature artists. Since we are measuring the number of pages that feature signature artists, a page that features signature artists is defined as a success and a page that does not feature signature artists is defined as a failure. There are 8 out of 560 pages that feature signature artists. Therefore the probability of a success $p=8560p=8560$ and the probability of a failure $q=1−p=1−8560=552560q=1−p=1−8560=552560$.
Both p and q remain the same for each page. Therefore, X is a binomial random variable, and it can be written as $X~B(100,8560)X~B(100,8560)$.
We can use a graphing calculator to answer Parts i to iii.
1. P(x = 2) = binompdf$(100,8560,2)(100,8560,2)$ = .2466
2. P(x ≤ 6) = binomcdf$(100,8560,6)(100,8560,6)$ = .9994
3. P(x > 3) = 1 – P(x ≤ 3) = 1 – binomcdf$(100,8560,3)(100,8560,3)$ = 1 – .9443 = .0557
1. mean = np = (100)$(8560)(8560)$ = $800560800560$ ≈ 1.4286
2. standard deviation = $npqnpq$ = $(100)(8560)(552560)(100)(8560)(552560)$ ≈ 1.1867
Try It 4.13
According to a poll, 60 percent of American adults prefer saving over spending. Let X = the number of American adults out of a random sample of 50 who prefer saving to spending.
1. What is the probability distribution for X?
2. Use your calculator to find the following probabilities:
1. The probability that 25 adults in the sample prefer saving over spending
2. The probability that at most 20 adults prefer saving
3. The probability that more than 30 adults prefer saving
3. Using the formulas, calculate the (i) mean and (ii) standard deviation of X.
Example 4.14
The lifetime risk of developing a specific disease is about 1 in 78 (1.28 percent). Suppose we randomly sample 200 people. Let X = the number of people who will develop the disease.
1. What is the probability distribution for X?
2. Using the formulas, calculate the (i) mean and (ii) standard deviation of X.
3. Use your calculator to find the probability that at most eight people develop the disease.
4. Is it more likely that five or six people will develop the disease? Justify your answer numerically.
Solution 4.14
1. This is a binomial experiment since all three characteristics are met. Each person is a trial. Since we sample 200 people, the number of trials is n = 200. For each person, there are two possible outcomes, will develop the disease or not. Since we are measuring the number of people who will develop the disease, a person will develop the disease is defined as a success and a person will not develop the disease is defined as a failure. The risk of developing the disease is 1.28 percent. Therefore the probability of a success, $p=1.28percent,.0128,p=1.28percent.0128$ and the probability of a failure, $q=1−p=1−.0128=.9872q=1−p=1−.0128=.9872$. Both p and q remain the same for each person. Therefore, X is a binomial random variable and it can be written as $X~B(200,.0128)X~B(200,.0128)$.
We can use a graphing calculator to answer Questions c and d.
1. Mean = np = 200(.0128) = 2.56
2. Standard Deviation =
2. Using the TI-83, 83+, 84 calculator with instructions as provided in Example 4.12:
P(x ≤ 8) = binomcdf(200, .0128, 8) = .9988
3. P(x = 5) = binompdf(200, .0128, 5) = .0707
P(x = 6) = binompdf(200, .0128, 6) = .0298
So P(x = 5) > P(x = 6); it is more likely that five people will develop the disease than six.
Try It 4.14
During the 2013 regular basketball season, a player had the highest field goal completion rate in the league. This player scored with 61.3 percent of his shots. Suppose you choose a random sample of 80 shots made by this player during the 2013 season. Let X = the number of shots that scored points.
1. What is the probability distribution for X?
2. Using the formulas, calculate the (i) mean and (ii) standard deviation of X.
3. Use your calculator to find the probability that this player scored with 60 of these shots.
4. Find the probability that this player scored with more than 50 of these shots.
Example 4.15
The following example illustrates a problem that is not binomial. It violates the condition of independence. ABC High School has a student advisory committee made up of 10 staff members and six students. The committee wishes to choose a chairperson and a recorder. What is the probability that the chairperson and recorder are both students? The names of all committee members are put into a box, and two names are drawn without replacement. The first name drawn determines the chairperson and the second name the recorder. There are two trials. However, the trials are not independent because the outcome of the first trial affects the outcome of the second trial. The probability of a student on the first draw is $616616$ because there are six students out of 16 members (10 staff members + six students). If the first draw selects a student, then the probability of a student on the second draw is $516516$ because there are only five students out of 15 members. If the first draw selects a staff member, then the probability of a student on the second draw is $615615$ because there are still six students out of 15 members. The probability of drawing a student's name changes for each of the trials and, therefore, violates the condition of independence.
Try It 4.15
A lacrosse team is selecting a captain. The names of all the seniors are put into a hat, and the first three that are drawn will be the captains. The names are not replaced once they are drawn (one person cannot be two captains). You want to see if the captains all play the same position. State whether this problem is binomial or not and state why. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 38, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8260054588317871, "perplexity": 364.2515447625097}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-39/segments/1537267160085.77/warc/CC-MAIN-20180924011731-20180924032131-00351.warc.gz"} |
https://faq.gutenberg.eu.org/3_composition/annexes/bibliographie/references_biblio_multiples?rev=1528031877 | Ceci est une ancienne révision du document !
— title: Multiple citations category: bibliographies tags: citations permalink: /FAQ-mcite —
A convention sometimes used in physics journals is to “collapse” a group of related citations into a single entry in the bibliography. BibTeX, by default, can't cope with this arrangement, but the [mcite](https://ctan.org/pkg/mcite) and [mciteplus](https://ctan.org/pkg/mciteplus) packages deal with the problem.
[mcite](https://ctan.org/pkg/mcite) overloads the \cite command to recognise a * at the start of a key, so that citations of the form latex \cite{paper1,*paper2} appear in the document as a single citation, and appear arranged appropriately in the bibliography itself. You're not limited to collapsing just two references. You can mix “collapsed” references with “ordinary” ones, as in latex \cite{paper0,paper1,*paper2,paper3} Which will appear in the document as 3 citations “[4,7,11]” (say) — citation “4” will refer to paper 0, “7” will refer to a combined entry for paper 1 and paper 2, and “11” will refer to paper 3.
You need to make a small change to the bibliography style (bst) file you use; the [mcite](https://ctan.org/pkg/mcite) package documentation tells you how to do that.
Most recent versions of [REVTeX](https://ctan.org/pkg/revtex4-1) (version 4.1 and later), in conjunction with recent versions of [natbib](https://ctan.org/pkg/natbib), already contain support for combined citations and so no longer even need [mciteplus](https://ctan.org/pkg/mciteplus) (but [mciteplus](https://ctan.org/pkg/mciteplus) is more general and will work with many other class and package combinations).
The [mciteplus](https://ctan.org/pkg/mciteplus) package adresses many of the infelicites of [mcite](https://ctan.org/pkg/mcite). Again, “ordinary” bst files will not work with [mciteplus](https://ctan.org/pkg/mciteplus), but the package documentation explains how to patch an existing BibTeX style.
The [collref](https://ctan.org/pkg/collref) package takes a rather different approach to the problem, and will work with most (if not all) BibTeX packages. [Collref](https://ctan.org/pkg/Collref) spots common subsets of the references, so if it sees a sequence latex \cite{paper0,paper1,paper2,paper3} … \cite{some_other_paper,paper1,paper2,and_another} it will collect paper1 and paper2 as a multiple reference.
3_composition/annexes/bibliographie/references_biblio_multiples.1528031877.txt.gz · Dernière modification: 2018/06/03 15:17 (modification externe) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9182353019714355, "perplexity": 4728.594733495725}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-17/segments/1618038084765.46/warc/CC-MAIN-20210415095505-20210415125505-00143.warc.gz"} |
http://math.stackexchange.com/questions/316849/intersection-of-conics-using-matrix-representation | # Intersection of conics using matrix representation
I came across a very interesting section of a wikipedia article on conics: http://en.wikipedia.org/wiki/Conic_section#Intersecting_two_conics
I am trying to work out a couple of examples to add to the page.
Example 1 - (this one turns out to be quite straight forward - see Example 2 below for a more general case):
Take these two hyperbolas, Q1 and Q2: Q1: $$x^2 - y^2 - 2 = 0$$ and Q2: $$.5x^2 - y^2 - 1 = 0$$
Their graphs which show that they have 2 real intersections are here: http://www.wolframalpha.com/input/?i=plot%28x^2+-+y^2+-+2+%3D+0+and+.5x^2+-+y^2+-+1+%3D+0%29
First, we construct their matrices: $$Q_1 = \begin{bmatrix}1 & 0 & 0\\0 & -1 & 0\\0 & 0 & -2\end{bmatrix}$$ $$Q_2 = \begin{bmatrix}1/2 & 0 & 0\\0 & -1 & 0\\0 & 0 & -1\end{bmatrix}$$
Then, we set $$det(\lambda Q_1 + \mu Q_2) = 0$$
Expanding this determinant, we get the equation: $$(\lambda + \frac{\mu}{2})(-\lambda-\mu)(-2\lambda-\mu) = 0$$
Here, each of the 3 factors can be independently set equal to zero to find the 3 solutions: $$\mu = -2\lambda$$ , $$\mu = -\lambda$$, and $$\mu = -2\lambda$$ , respectively.
Alternatively, we could immediately set $\lambda=1$ and solve $\mu^3/2+(5 \mu^2)/2+4 \mu+2$ algorithmically.
There three degenerate conics? I.e. if we take one of the solutions ($\mu = -\lambda$), and use it to compute a particular linear combination (plugging into the linear combination equation $\lambda C_1 + \mu C_2$), we get:
$$\lambda C_1 -\lambda C_2$$
which is still an expression with an unknown? Does it mean we can choose any $\lambda$ to obtain a degenerate conic? That is, set $\lambda=1$ to get:
$$C_0 = \begin{bmatrix}.5 & 0 & 0\\0 & 0 & 0\\0 & 0 & -1\end{bmatrix}$$
Now we identify two coincident lines constituting this degenerate conic. We set $x^T C_0 x$ equal to zero, and we get $$.5x^2 - 1=0$$. We see that $$x=+/-\sqrt{2}$$ (a pair of vertical lines). Intersecting these lines with the conics will give the intersection points of the original conics. Here, since the lines are vertical we can simply substitute the values $$x=\sqrt{2}$$ and $$x=-\sqrt{2}$$ to obtain the intersections (there are only 2 in this problem, but there can be up to 4):
From Q_1: $$(\sqrt{2})^2 - y^2 - 2 = 0 \rightarrow y=0$$ $$(-\sqrt{2})^2 - y^2 - 2 = 0 \rightarrow y=0$$
we get intersection points $$(\sqrt{2}, 0)$$ and $$(-\sqrt{2},0)$$.
From Q_2: $$.5(\sqrt{2})^2 - y^2 - 1 = 0 \rightarrow y=0$$ $$.5(-\sqrt{2})^2 - y^2 - 1 = 0 \rightarrow y=0$$
we get intersection points $$(\sqrt{2}, 0)$$ and $$(-\sqrt{2},0)$$.
Example #2
Take these two hyperbolas, Q1 and Q2: Q1: $$.5x^2 - y^2 + .1xy + 1 = 0$$ and Q2: $$-x^2 + y^2 + 1 = 0$$
Their graphs which show that they have 4 real intersections are here:
First, we construct their matrices: $$Q_1 = \begin{bmatrix}.5 & .05 & 0\\.05 & -1 & 0\\0 & 0 & 1\end{bmatrix}$$ $$Q_2 = \begin{bmatrix}-1 & 0 & 0\\0 & 1 & 0\\0 & 0 & 1\end{bmatrix}$$
Then, we set $$det(\lambda Q_1 + \mu Q_2) = 0$$
Expanding this determinant, we get the equation: $$-.5\lambda^3 + \lambda^2\mu +.5\lambda\mu^2-\mu^3 - .0025\lambda^3 - .0025\lambda^2\mu$$
Arbitrarily setting $\lambda=1$ and expanding, we get the equation $$-\mu^3+.5\mu^2+.9975\mu-.5025=0$$
The 3 (approximate) solutions are: $$\mu = -1$$ , $$\mu = .505$$, and $$\mu = .99495$$ , respectively.
Going back and constructing the degenerate conic matrix (with $\lambda=1$ and $\mu=-1$), we have (Can you just pick one of the 3 solutions that comes from the determinant equation as I did?)
$$C_0 = \begin{bmatrix}1.5 & .05 & 0\\.05 & -2 & 0\\0 & 0 & 0\end{bmatrix}$$
Now $$x^T C_0 x = 0 =$$ we get $$1.5x^2 + .1xy-2y^2 = 0$$.
Solving for $y$, we see that the two lines are $$y=−0.841386x$$ and $$y=0.891386x$$.
These lines intersect the conics at exactly the intersection points of the conics, as seen here: http://www.wolframalpha.com/input/?i=plot%28.5x^2-y^2%2B.1xy%2B1%3D0+and+-x^2%2By^2%2B1%3D0+and+y+%3D+%E2%88%920.841386x+and+y%3D0.891386x%29
The intersection points can be found by substituting the equation of both lines in to the equation of both conics. For example, substituting $$y=−0.841386x$$ into $$.5x^2 - y^2 + .1xy + 1 = 0$$ we get $$x=1.8505$$ Plugging this into the equation of the line $y=−0.841386x$, we see that one intersection point is $(1.8505, -1.5569)$. The other 3 intersection points can be found identically.
-
you have computed $C_0$ incorrectly. instead of $Q_1 - Q_2$, you have calculated $Q_1 + Q_2$! – achille hui Feb 28 '13 at 14:21
@achillehui Woops, you are correct! I fixed it (did I do it right this time :)), but have a similar problem in interpreting the result. – David Doria Feb 28 '13 at 14:45
Nope, $C_0 = Q_1 - Q_2$ should be $$\begin{pmatrix}\frac12 & 0 & 0\\0 & 0 & 0\\0 & 0 & -1\end{pmatrix}$$ which corresponds to $\frac12 x^2 - 1 = 0 \Leftrightarrow x = \pm \sqrt{2}$. i.e. a pair of vertical lines tangent to the two curves at $(\pm \sqrt{2}, 0)$ – achille hui Feb 28 '13 at 15:51
@achillehui Gah, sorry. Ok, I think I finished the example problem. However, since the lines were vertical in this case, it was very easy to compute the intersection point. In general, the wiki page says "intersect each identified line with either one of the two original conics; this step can be done efficiently using the dual conic representation of C_0". Can you explain this step? – David Doria Feb 28 '13 at 17:27
Not sure what the wiki page means. But once you have the equation of a line, substitute it into $Q_1$ or $Q_2$ give you a quadratic equation to solve. – achille hui Feb 28 '13 at 17:45
## 1 Answer
hope I can help you out improving these examples. I am the author of that brief description of how to intesect two conics that is giving you headaches!
I will first concentrate on example 1. You actually used two tangent hyperbolae. That might gives some numerical error when computing the intersection using a numerical algorithm (like the one I wrote for Matlab www.mathworks.it/matlabcentral/fileexchange/28318-conics-intersection).
Let's consider two well intersecting parabolae like: $$C_1 = \begin{bmatrix}1 & 0 & 0\\0 & 0 & -1/2\\0 & -1/2 & 0\end{bmatrix}$$ $$C_2 = \begin{bmatrix}3 & 0 & 0\\0 & 0 & -1/2\\0 & -1/2 & -2\end{bmatrix}$$
whose equations are $x^2 - y = 0$ and $3x^2 - y - 2 = 0$ respectively. The intersection can be seen in the following plot:
It is possible to verify that these two conics intersects in two points $$p_1 = \begin{bmatrix}1 & -1 & 1\end{bmatrix}$$ $$p_2 = \begin{bmatrix} 1 & 1 & 1\end{bmatrix}$$ expressed in homogeneous coordinates.
Let's now estimate the intersection numerically. For this reason we are going to build a pencil of conics that contains both C1 and C2, i.e.
$$C_\lambda = C_1 + \lambda C_2$$
Notice that the intersection points lie on $C_\lambda$ for any value of $\lambda$, i.e:
$$p_1^T C_\lambda p_1 = 0 \quad \forall \lambda$$ $$p_2^T C_\lambda p_2 = 0 \quad \forall \lambda$$
We are going to exploit this properties by detecting an "easy to handle" conic that belongs to the pencil. In particular we exploit the conic of the pencil that is represented by straight lines intersecting both $p_1$ and $p_2$. This is a degenerate conic (indeed is a set of straight lines) whose conic matrix deterimant is vanishing.
Thus we are looking for the value $\lambda$ such that $det(C_\lambda) = 0$. $\lambda$ is sought by using the characteristic polynomial of the pencil of conics.
We initially transform the pencil of conics as:
$$-(C_1 + \lambda C_2) \cdot (-C_2)^{-1} = \lambda I - C_1 \cdot (-C_2)^{-1} = \lambda I - A$$
Solving $det(C_1 + \lambda C_2) = 0$ is equivalent to solve $det(\lambda I - A) = 0$. In this new formulation, though, $\lambda$ represents the eigenvalue of matrix A and $det(\lambda I - A)$ is the characteristic polynomial of A.
In our example $$A = C_1 \cdot (-C_2)^{-1} = \begin{bmatrix}-1/3 & 0 & 0\\0 & -1 & 0\\0 & 4 & -1\end{bmatrix}$$
We then solve the characteristic polynomial (a 3rd degree polynom) for $\lambda$ $$det(\lambda I - A) = 0$$ This characteristic polynomial of A (a 3x3 matrix) can be written as: $$-\lambda^3 + \lambda^2 trace(A) - \lambda (det(A_{12}) + det(A_{23}) +det(A_{13})) +det(A) = 0$$
In our case the solutions of $$-\lambda^3 + 7/3 \lambda^2 - 5/3 \lambda - 1/3 = 0$$ are (-1, -1, -1/3). Since these are all real values we can select one and use it to identify our degenerate conic of the pencil. In particular $\lambda = -1$ gives
$$C_d = C_1 -1 \cdot C_2 = \begin{bmatrix}-2 & 0 & 0\\0 & 0 & 0\\0 & 0 & 2\end{bmatrix}$$
whose determinant is indeed zero.
As we said $C_d$ represent a degenerate conic. In particular it can be decomposed as the multiplication of two straight lines m and l: $$C_d = m \cdot l^T + l \cdot m^T$$
(here are the details on how to perform the Decomposition of a degenerate conic)
In particular in our case $$l = \begin{bmatrix}1 & 0 & 1\end{bmatrix}$$ $$m = \begin{bmatrix} -1 & 0 & 1\end{bmatrix}$$ represent two vertical lines.
By intersecting the two lines with one of the two conics (say $C_1$) we get the two intersection points $p_1$ and $p_2$. This is done by solving the systems:
\left\{ \begin{align} p_1^T \cdot C_1 \cdot p_1 &= 0 \\ l \cdot p_1 &= 0 \\ \end{align} \right.
\left\{ \begin{align} p_2^T \cdot C_1 \cdot p_2 &= 0 \\ m \cdot p_2 &= 0 \\ \end{align} \right.
-
Great answer! -filler for the comment- – Juanlu001 Oct 20 '13 at 19:10 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 2, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9932756423950195, "perplexity": 288.07604570417936}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-35/segments/1440645348533.67/warc/CC-MAIN-20150827031548-00007-ip-10-171-96-226.ec2.internal.warc.gz"} |
http://mathhelpforum.com/pre-calculus/108302-easy-simplification-function-print.html | # Easy simplification of a function
• October 15th 2009, 03:55 PM
Evan.Kimia
Easy simplification of a function
http://img337.imageshack.us/img337/7410/problem3b.jpg
I understand how they did everything except the last step, from 1/(-s/(s+1)^2) to -(s+1)^2/s
Could someone clarify? Thanks.
• October 15th 2009, 04:26 PM
Defunkt
Quote:
Originally Posted by Evan.Kimia
http://img337.imageshack.us/img337/7410/problem3b.jpg
I understand how they did everything except the last step, from 1/(-s/(s+1)^2) to -(s+1)^2/s
Could someone clarify? Thanks.
Well...
Using the fact that $\frac{1}{\frac{u}{v}} = 1 \cdot \frac{v}{u} \Rightarrow \frac{1}{\frac{s}{(s+1)^2}} = 1 \cdot \frac{(s+1)^2}{s}$
That is, dividing a term by x is like multiplying it by $\frac{1}{x}$. In this example, our x is $-\frac{s}{(s+1)^2}$ and so our 1/x is $-\frac{(s+1)^2}{s}$
• October 15th 2009, 04:27 PM
skeeter
Quote:
Originally Posted by Evan.Kimia
http://img337.imageshack.us/img337/7410/problem3b.jpg
I understand how they did everything except the last step, from 1/(-s/(s+1)^2) to -(s+1)^2/s
Could someone clarify? Thanks.
remember how to divide by a fraction?
$\frac{1}{a/b} = 1 \cdot \frac{b}{a} = \frac{b}{a}$
• October 15th 2009, 05:50 PM
Evan.Kimia
Thats what i thought, i wanted to be certain. Thanks! | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 5, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8947290182113647, "perplexity": 2547.6505096901324}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-30/segments/1469257831771.10/warc/CC-MAIN-20160723071031-00167-ip-10-185-27-174.ec2.internal.warc.gz"} |
https://elethom.me/en/2018/hackintosh | # Hackintosh in 2018
## macOS Mojave 10.14.1 on Coffee Lake
I assembled myself a desktop PC after winning a Core i7-8086K in the giveaway event. As a macOS user for years, I've been wondering if I could put more use into it other than gaming. So I started to try installing a macOS on it.
# Preparation
## The Original Setup
Here is the setup with cost in CN¥ (¥17000 in total):
• Intel Core i7-8086K - free
• ASRock Z370 Taichi - 1500
• G.Skill DDR4-3200 (C14) 8 GB * 2 - 1700
• ASUS DUAL RTX2080 O8G - 6500
• SAMSUNG 970 EVO 500 GB * 2 - 2000
• CORSAIR H100i v2 - 800
• CORSAIR RM650x - 850
• NZXT H440 Matte Black - 500
• DELL S2417DG - 2900
• Creative Inspire T12 - 250
For other external devices, I already had these so there's no extra cost:
• Apple Keyboard
• SteelSeries Sensei RAW
## Specifications
Here are the specs with details:
• Intel Core i7-8086K (8th Gen Coffee Lake)
• Intel UHD 630 Graphics (built-in)
• ASRock Z370 Taichi
• Intel Z370 Chipset
• Realtek ALC1220 (Audio)
• Intel I219-V (Ethernet)
• Intel I211-AT (Ethernet) 1
• Intel AC 3168 (Wi-Fi & Bluetooth) 2
• Broadcom BCM943602CS (Wi-Fi & Bluetooth)
• ASMedia ASM3142 (USB 3.1 Gen 2)
• ASMedia ASM1074 (USB 3.1 Gen 1)
• G.Skill DDR4-3200 (C14) 8 GB * 2 (with XMP on)
• ASUS DUAL RTX2080 O8G 3
• SAMSUNG 970 EVO NVMe SSD 500 GB * 2 4
For install media, I bought a SanDisk CZ800 128 GB (200 CN¥). And I have a 15″ MacBook Pro (Mid 2015) to do all the pre-install work.
## Need-to-knows Before Installation
There are two keys to installing macOS on a PC:
• Let the system recognise the hardware
We use Clover EFI Bootloader to do both and Clover Configurator to configure it.
Here's an example of installing macOS Mojave 10.14.1.
# Pre-install
While downloading, erase the USB disk with Disk Utility. Note that the scheme should be "GUID Partition Map" and the format should be "Mac OS Extended (Journaled)".
Then, use the command line tool to create install media as followed (note that the volume name should be changed if you use a different volume name):
\$ /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/Install\ macOS\ Mojave/
• Clover for UEFI booting only
• Install Clover in the ESP
• UEFI Drivers
• VBoxHfs-64
• AptioMemoryFix-64
We are using a UEFI motherboard so that we should install Clover for UEFI booting. And Clover should be installed in the ESP (EFI System Partition) used for booting the system. VBoxHfs-64 and ApfsDriverLoader-64 are EFI drivers for Clover to recognize partitions of HFS or APFS format. AptioMemoryFix-64 is used to fix memory problems on UEFI firmware, for example, AMI Aptio used by my ASRock Z370 Taichi.
## Configure Clover and Install Kexts
To configure Clover, mount the ESP under "Mount EFI" section. Then, load /EFI/CLOVER/config.plist.
First, deselect and delete everything you see in the Clover Configurator for a clean install.
### Must-have Kernel Extensions
Kexts (kernel extensions) should be put under the corresponding directories in /EFI/Clover/kexts.
FakeSMC is a must. Its sensor plugins are recommended.
Lilu is needed for other patches coming in the form of kernel extensions.
### Intel Core i7-8086K CPU
Core i7-8086K is an 8th Gen Coffee Lake CPU. So FakeCPUID is not needed. All we've got to do is add a "change HECI to IMEI" patch (find 48454349 replace 494D4549) to DSDT and check FixHeaders under "ACPI" section to fix mach reboot problems. Halt Enabler for preventing shut down and reboot problems is not needed in my case, however YMMV. Additionally, Generate PStates and Generate CStates are recommended for Turbo Boost. And dart=0 boot flag should be checked to disable VT-d if it's enabled in the BIOS, just like the old times.
### Intel UHD 630 Built-in iGPU
For Coffee Lake, setting ig-platform-id or -disablegfxfirmware boot flag is no longer needed. Instead, we need to add "change GFX0 to IGPU" (find 47465830 replace 49475055) and "change PEGP to GFX0" (find 50454750 replace 47465830) patches to DSDT. Make sure the former is patched before the latter or something very wrong is going to happen.
On the other hand, IntelGraphicsFixup is obsolete, too. It's replaced by WhateverGreen.
### Realtek ALC1220 Audio
First, add "change HDAS to HDEF" patch (find 48444153 replace 48444546) to DSDT.
Use AppleALC to enable native HD audio. Add alcid=layout-id (alcid=11 works for me) boot flag to enable it. Supported codecs can be looked up in the wiki. There might be more than one layout for each codec. Try each of them to find the best one working.
Additionally, AFGLowPowerState should be used if there are noises when idling and ResetHDA should be used if there is no sound after a cold boot. They are both under "Devices/Audio" section.
### Intel I219-V Ethernet
Use IntelMausiEthernet for Intel I219-V.
### Broadcom BCM943602CS Wi-Fi & Bluetooth
I bought a Broadcom BCM943602CS Airport card and plugged it in using a PCIe adaptor. Note that the Bluetooth module needs to be connected to an onboard USB 2.0 header to work. Also, certain x16 full-length PCIe slots on some motherboards work only with graphics cards (mine is one of them).
If you already have a certain type of device recognised but not functional. You need to disable it. In my case, my Intel Bluetooth device needs to be disabled for the Broadcom one to work. You can find the port name with IORegistryExplorer. It's usually under one of the USB hubs. It's HS09 for me. Then, add uia_exclude=port-name (mine is uia_exclude=HS09) boot flag to disable it.
The Airport card should be fully functional without any hacks.
### Coffee Lake and Third-party (ASMedia) USB
First, add a USB port limit kext patch (each version of macOS has a different method to patch it, this only works on 10.14.1):
• Name: com.apple.driver.usb.AppleUSBXHCI
• Find 83FB0F0F 838F0400 00
• Replace 83FB0F90 90909090 90
Then, use USBInjectAll to make every USB controller fully functional.
Additionally, FixOwnership option under "Devices/USB" section would be needed if you cannot enable XHCI handoff in the BIOS.
### SAMSUNG 970 EVO NVMe SSD
NVMe is natively supported by 10.14.1 and TRIM is enabled by default. So there is nothing we need to do.
### Generate SMBIOS
In the "SMBIOS" section, use the drop-down menu to pick a model with specs similar to the PC. Mobile option is related to power management. For laptops, it should be checked. Trust option should be used when memory is not recognised correctly. Click "Check Coverage" to check if the serial number is being used by a real Mac to avoid conflict.
This step should make App Store, iCloud, iMessage, FaceTime services fully functional.
# Install
From here, we are all done. Plug in the USB disk and boot from the UEFI partition on it. Choose "Install macOS Mojave" in Clover's GUI. Press space to use extra boot flags if you need them. For example, '-v' for verbose if you encounter any errors. Press enter to boot.
First, erase the whole disk with Disk Utility. Note that the scheme should be "GUID Partition Map" and the format should be "APFS". Then, close Disk Utility. Choose "Install macOS Mojave" and follow the steps.
# Post-install
After installation, repeat the steps to install Clover EFI Bootloader to your system partition. Copy and paste /EFI/BOOT and /EFI/CLOVER from your install partition to the corresponding location in your system partition. Then, we have a fully functional bootable macOS installed.
Set Timeout to 0 under "Boot" section in Clover Configurator to boot directly to macOS without Clover's GUI.
# Known-Issues
• Not all sensors are working
• No fan controls
• Screen flickers between first and second stages of booting
• Intel Power Gadget displays 0 GHz GFX frequency (correction: real Mac does that, too)
• There's a small delay when shutting down or restarting
Some says the iGPU issues can be fixed by an Intel Framebuffer patch. I've looked into it but no luck yet.
1. I only need one (actually none) of the cabled ethernet controllers, so the other one is ignored.
2. There are no existing solutions for Intel Wi-Fi & Bluetooth product. So I bought an Airport card from a dissembled Mac instead.
3. There is no support for 20 series yet. Primary GPU should be set to onboard for using macOS.
4. One for Windows, one for macOS. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.16071636974811554, "perplexity": 17785.177674821465}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-05/segments/1579250628549.43/warc/CC-MAIN-20200125011232-20200125040232-00051.warc.gz"} |
https://chemistry.stackexchange.com/questions/134114/electrophilic-attack-of-x-on-double-bond | # Electrophilic attack of X+ on double bond
Is it the double bond attacking the $$\ce{X+}$$ ion or the other way around?
Also, does it form a cyclic transition state if it isn't bromine or chlorine?
Eg. cyclohexene $$+ \,\ce{Cl+ ->}$$ cyclic transition state
But would the same thing happen if I put any other electrophile?
These kind of reactions are called Electrophilic addition reactions. These are usually given by alkenes and alkynes. In your example, the electrophile is $$\ce{Cl+}$$. The alkene will act as a source of π electrons and will donate it to the electrophile which is in need of electrons. So, alkene is called as nucleophile in this reaction.
Is it the double bond attacking the X+ ion or the other way around?
It depends on how you look at it. We can say that alkene polarizes the $$\ce{Cl-Cl}$$ bond by pushing electrons into the anti-bonding molecular orbital. This weakens the bond and hence electrophile is getting generated. In the next step,the electrophile attacks the double bond [or double bond attacks the electrophile] and hence electrophile gets added across across the double bond
Why does the 3-membered cyclic transition state form?
The cyclic transition state is just a temporary relief for the electrophile that's just been added. The π molecular orbital donates electrons to the electrophile.
While the p-orbitals in the π-bond overlap with the electrophile, each p-orbital forms a σ-bond.
But would the same thing happen if I put any other electrophile?
Generally,electrophilic addition reactions take place through carbocation intermediate. But this reaction can take place through cyclic 3-membered intermediate,if the electrophile has a lone pair.
Apart from $$\ce{Cl+,Br+}$$ even $$\ce{Hg^2+}$$ (when the reagent is $$\ce{Hg(OAc)2/H3O+}$$) and $$\ce{NO+}$$ (when the reagent is $$\ce{NOCl}$$) can form the 3-membered cyclic intermediate.
• This is my first answer.Can anyone verify whether what I have written is correct? Please suggest some tips on answering and tell what I can improve on,so that I can write better answers in the future.Thanks :) – Chem-Learner May 22 '20 at 8:40
• Include references if you have them – Waylander May 22 '20 at 9:17
• thanks at lot actually this helped :) – ganuwoahh May 22 '20 at 14:55
• @Waylander,Thanks for the suggestion.Unfortunately,I don't have any such references for this.If you have them, you can add them so that the answer is complete.Thanks – Chem-Learner May 22 '20 at 18:41
• @ganuwoahh Thanks for the feedback.It's nice to hear that it helped you :) – Chem-Learner May 22 '20 at 18:42 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 9, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7120459675788879, "perplexity": 2268.6309619763283}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-21/segments/1620243989856.11/warc/CC-MAIN-20210511184216-20210511214216-00451.warc.gz"} |
https://discourse.matplotlib.org/t/use-matplotlib-to-produce-mathathematical-expression-only/15457 | # use matplotlib to produce mathathematical expression only
Hello,
I want to produce a eps file of following mathematical expression:
r'$F(x)=p*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}$'
is it possible to somehow missuse matplotlib for that to produce only the function without any other plot things? Or is there a better python library within scipy? I don't want to install the complete latex libraries just for producing this single eps file.
thank you
/johannes
···
--
NEU: FreePhone - kostenlos mobil telefonieren und surfen!
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Check out mathtex. It is matplotlib's TeX parsing engine and renderer
broken out into a separate library:
Also, please send matplotlib questions just to the matplotlib list. Thanks.
···
Hello,
I want to produce a eps file of following mathematical expression:
r'$F(x)=p*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}$'
is it possible to somehow missuse matplotlib for that to produce only the function without any other plot things? Or is there a better python library within scipy? I don't want to install the complete latex libraries just for producing this single eps file.
--
Robert Kern
"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
-- Umberto Eco
-------- Original-Nachricht --------
Datum: Mon, 16 May 2011 08:28:49 -0500
Von: Robert Kern <robert.kern@...287...>
An: SciPy Users List <scipy-user@...177...>
CC: matplotlib-users@lists.sourceforge.net
Betreff: Re: [Matplotlib-users] [SciPy-User] use matplotlib to produce mathathematical expression only
> Hello,
>
> I want to produce a eps file of following mathematical expression:
>
r'$F(x)=p*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}$'
>
> is it possible to somehow missuse matplotlib for that to produce only
the function without any other plot things? Or is there a better python
library within scipy? I don't want to install the complete latex libraries just
for producing this single eps file.
Check out mathtex. It is matplotlib's TeX parsing engine and renderer
broken out into a separate library:
I also thought about mathtex but don't know how to use my mathematical expression without a plot of axis etc. any suggestions? I just want to have the formated math expression as eps and I don't know how to do it, still after reading in the matplotlib-manual.
/johannes
···
Also, please send matplotlib questions just to the matplotlib list.
Thanks.
--
Robert Kern
"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
-- Umberto Eco
------------------------------------------------------------------------------
Achieve unprecedented app performance and reliability
What every C/C++ and Fortran developer should know.
Learn how Intel has extended the reach of its next-generation tools
to help boost performance applications - inlcuding clusters.
http://p.sf.net/sfu/intel-dev2devmay
_______________________________________________
Matplotlib-users mailing list
Matplotlib-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/matplotlib-users
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We have added a new feature to do just that in the development branch,
but it should be fairly trivial to do with existing releases of
matplotlib. Just create a figure object and use its figtitle to hold
the expression and then save the figure.
Ben Root
···
-------- Original-Nachricht --------
Datum: Mon, 16 May 2011 08:28:49 -0500
Von: Robert Kern <robert.kern@...287...>
An: SciPy Users List <scipy-user@...177...>
CC: matplotlib-users@lists.sourceforge.net
Betreff: Re: [Matplotlib-users] [SciPy-User] use matplotlib to produce mathathematical expression only
> Hello,
>
> I want to produce a eps file of following mathematical expression:
>
r'$F(x)=p*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}$'
>
> is it possible to somehow missuse matplotlib for that to produce only
the function without any other plot things? Or is there a better python
library within scipy? I don't want to install the complete latex libraries just
for producing this single eps file.
Check out mathtex. It is matplotlib's TeX parsing engine and renderer
broken out into a separate library:
I also thought about mathtex but don't know how to use my mathematical expression without a plot of axis etc. any suggestions? I just want to have the formated math expression as eps and I don't know how to do it, still after reading in the matplotlib-manual.
/johannes
Also, please send matplotlib questions just to the matplotlib list.
Thanks.
--
Robert Kern
"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
-- Umberto Eco
------------------------------------------------------------------------------
Achieve unprecedented app performance and reliability
What every C/C++ and Fortran developer should know.
Learn how Intel has extended the reach of its next-generation tools
to help boost performance applications - inlcuding clusters.
http://p.sf.net/sfu/intel-dev2devmay
_______________________________________________
Matplotlib-users mailing list
Matplotlib-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/matplotlib-users
--
NEU: FreePhone - kostenlos mobil telefonieren und surfen!
Jetzt informieren: http://www.gmx.net/de/go/freephone
_______________________________________________
SciPy-User mailing list
SciPy-User@...177...
http://mail.scipy.org/mailman/listinfo/scipy-user
The mathtex that I link to above is a separate library, not a part of
···
-------- Original-Nachricht --------
Datum: Mon, 16 May 2011 08:28:49 -0500
Von: Robert Kern <robert.kern@...287...>
An: SciPy Users List <scipy-user@...177...>
CC: matplotlib-users@lists.sourceforge.net
Betreff: Re: [Matplotlib-users] [SciPy-User] use matplotlib to produce mathathematical expression only
> Hello,
>
> I want to produce a eps file of following mathematical expression:
>
r'$F(x)=p*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}$'
>
> is it possible to somehow missuse matplotlib for that to produce only
the function without any other plot things? Or is there a better python
library within scipy? I don't want to install the complete latex libraries just
for producing this single eps file.
Check out mathtex. It is matplotlib's TeX parsing engine and renderer
broken out into a separate library:
I also thought about mathtex but don't know how to use my mathematical expression without a plot of axis etc. any suggestions? I just want to have the formated math expression as eps and I don't know how to do it, still after reading in the matplotlib-manual.
--
Robert Kern
"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
-- Umberto Eco
-------- Original-Nachricht --------
Datum: Mon, 16 May 2011 09:49:24 -0500
Von: Benjamin Root <ben.root@...1304...>
An: "matplotlib-users@lists.sourceforge.net" <matplotlib-users@lists.sourceforge.net>
Betreff: Re: [Matplotlib-users] [SciPy-User] use matplotlib to produce mathathematical expression only
>
> -------- Original-Nachricht --------
>> Datum: Mon, 16 May 2011 08:28:49 -0500
>> Von: Robert Kern <robert.kern@...287...>
>> An: SciPy Users List <scipy-user@...177...>
>> CC: matplotlib-users@lists.sourceforge.net
>> Betreff: Re: [Matplotlib-users] [SciPy-User] use matplotlib to produce
mathathematical expression only
>
>> > Hello,
>> >
>> > I want to produce a eps file of following mathematical expression:
>> >
>>
r'$F(x)=p*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}$'
>> >
>> > is it possible to somehow missuse matplotlib for that to produce only
>> the function without any other plot things? Or is there a better python
>> library within scipy? I don't want to install the complete latex
libraries just
>> for producing this single eps file.
>>
>> Check out mathtex. It is matplotlib's TeX parsing engine and renderer
>> broken out into a separate library:
>>
>
> I also thought about mathtex but don't know how to use my mathematical
expression without a plot of axis etc. any suggestions? I just want to have
the formated math expression as eps and I don't know how to do it, still
>
> /johannes
>
>
>>
>> Also, please send matplotlib questions just to the matplotlib list.
>> Thanks.
>>
>> --
>> Robert Kern
>>
>> "I have come to believe that the whole world is an enigma, a harmless
>> enigma that is made terrible by our own mad attempt to interpret it as
>> though it had an underlying truth."
>> -- Umberto Eco
>>
>>
------------------------------------------------------------------------------
>> Achieve unprecedented app performance and reliability
>> What every C/C++ and Fortran developer should know.
>> Learn how Intel has extended the reach of its next-generation tools
>> to help boost performance applications - inlcuding clusters.
>> http://p.sf.net/sfu/intel-dev2devmay
>> _______________________________________________
>> Matplotlib-users mailing list
>> Matplotlib-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>
> --
> NEU: FreePhone - kostenlos mobil telefonieren und surfen!
> Jetzt informieren: http://www.gmx.net/de/go/freephone
> _______________________________________________
> SciPy-User mailing list
> SciPy-User@...177...
> http://mail.scipy.org/mailman/listinfo/scipy-user
>
We have added a new feature to do just that in the development branch,
but it should be fairly trivial to do with existing releases of
matplotlib. Just create a figure object and use its figtitle to hold
the expression and then save the figure.
It might be trivial but how to remove the axis/plot then and crop the extend of the eps?
I tried:
plt.figure()
plt.title(r'$F(x)=p*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}$', fontsize=20)
plt.show()
/j
···
>> On Mon, May 16, 2011 at 08:21, Johannes Radinger <JRadinger@...1843...> > wrote:
Ben Root
------------------------------------------------------------------------------
Achieve unprecedented app performance and reliability
What every C/C++ and Fortran developer should know.
Learn how Intel has extended the reach of its next-generation tools
to help boost performance applications - inlcuding clusters.
http://p.sf.net/sfu/intel-dev2devmay
_______________________________________________
Matplotlib-users mailing list
Matplotlib-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/matplotlib-users
--
NEU: FreePhone - kostenlos mobil telefonieren und surfen!
Jetzt informieren: http://www.gmx.net/de/go/freephone
Use figtext instead. I did the following and it looked fine to me:
plt.figure()
plt.figtext(0.1, 0.5, r’$F(x)=p*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}$’, fontsize=20)
plt.show()
I hope that helps!
Ben Root
···
On Mon, May 16, 2011 at 10:21 AM, Johannes Radinger <JRadinger@…1843…> wrote:
-------- Original-Nachricht --------
Datum: Mon, 16 May 2011 09:49:24 -0500
Von: Benjamin Root <ben.root@…1304…>
Betreff: Re: [Matplotlib-users] [SciPy-User] use matplotlib to produce mathathematical expression only
-------- Original-Nachricht --------
Datum: Mon, 16 May 2011 08:28:49 -0500
Von: Robert Kern <robert.kern@…287…>
An: SciPy Users List <scipy-user@…177…>
Betreff: Re: [Matplotlib-users] [SciPy-User] use matplotlib to produce
mathathematical expression only
On Mon, May 16, 2011 at 08:21, Johannes Radinger <JRadinger@…1843…> > > > wrote:
Hello,
I want to produce a eps file of following mathematical expression:
r’$F(x)=p*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}$’
is it possible to somehow missuse matplotlib for that to produce only
the function without any other plot things? Or is there a better python
library within scipy? I don’t want to install the complete latex
libraries just
for producing this single eps file.
Check out mathtex. It is matplotlib’s TeX parsing engine and renderer
broken out into a separate library:
I also thought about mathtex but don’t know how to use my mathematical
expression without a plot of axis etc. any suggestions? I just want to have
the formated math expression as eps and I don’t know how to do it, still
/johannes
Also, please send matplotlib questions just to the matplotlib list.
Thanks.
Robert Kern
"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
– Umberto Eco
Achieve unprecedented app performance and reliability
What every C/C++ and Fortran developer should know.
Learn how Intel has extended the reach of its next-generation tools
to help boost performance applications - inlcuding clusters.
http://p.sf.net/sfu/intel-dev2devmay
Matplotlib-users mailing list
Matplotlib-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/matplotlib-users
NEU: FreePhone - kostenlos mobil telefonieren und surfen!
Jetzt informieren: http://www.gmx.net/de/go/freephone
SciPy-User mailing list
SciPy-User@…177…
http://mail.scipy.org/mailman/listinfo/scipy-user
We have added a new feature to do just that in the development branch,
but it should be fairly trivial to do with existing releases of
matplotlib. Just create a figure object and use its figtitle to hold
the expression and then save the figure.
It might be trivial but how to remove the axis/plot then and crop the extend of the eps?
I tried:
plt.figure()
plt.title(r’$F(x)=p*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}$’, fontsize=20)
plt.show()
/j
-------- Original-Nachricht --------
Datum: Mon, 16 May 2011 10:59:34 -0500
Von: Benjamin Root <ben.root@...1304...>
CC: matplotlib-users@lists.sourceforge.net
Betreff: Re: [Matplotlib-users] use matplotlib to produce mathathematical expression only
>
> -------- Original-Nachricht --------
> > Datum: Mon, 16 May 2011 09:49:24 -0500
> > Von: Benjamin Root <ben.root@...1304...>
> > An: "matplotlib-users@lists.sourceforge.net" <
> matplotlib-users@lists.sourceforge.net>
> > Betreff: Re: [Matplotlib-users] [SciPy-User] use matplotlib to produce
> mathathematical expression only
>
> > >
> > > -------- Original-Nachricht --------
> > >> Datum: Mon, 16 May 2011 08:28:49 -0500
> > >> Von: Robert Kern <robert.kern@...287...>
> > >> An: SciPy Users List <scipy-user@...177...>
> > >> CC: matplotlib-users@lists.sourceforge.net
> > >> Betreff: Re: [Matplotlib-users] [SciPy-User] use matplotlib to
produce
> > mathathematical expression only
> > >
> > >> > Hello,
> > >> >
> > >> > I want to produce a eps file of following mathematical
expression:
> > >> >
> > >>
> >
>
r'$F(x)=p*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}$'
> > >> >
> > >> > is it possible to somehow missuse matplotlib for that to produce
> only
> > >> the function without any other plot things? Or is there a better
> python
> > >> library within scipy? I don't want to install the complete latex
> > libraries just
> > >> for producing this single eps file.
> > >>
> > >> Check out mathtex. It is matplotlib's TeX parsing engine and
renderer
> > >> broken out into a separate library:
> > >>
> > >
> > > I also thought about mathtex but don't know how to use my
mathematical
> > expression without a plot of axis etc. any suggestions? I just want to
> have
> > the formated math expression as eps and I don't know how to do it,
still
> > after reading in the matplotlib-manual.
> > >
> > > /johannes
> > >
> > >
> > >>
> > >> Also, please send matplotlib questions just to the matplotlib list.
> > >> Thanks.
> > >>
> > >> --
> > >> Robert Kern
> > >>
> > >> "I have come to believe that the whole world is an enigma, a
harmless
> > >> enigma that is made terrible by our own mad attempt to interpret it
as
> > >> though it had an underlying truth."
> > >> -- Umberto Eco
> > >>
> > >>
> >
>
------------------------------------------------------------------------------
> > >> Achieve unprecedented app performance and reliability
> > >> What every C/C++ and Fortran developer should know.
> > >> Learn how Intel has extended the reach of its next-generation tools
> > >> to help boost performance applications - inlcuding clusters.
> > >> http://p.sf.net/sfu/intel-dev2devmay
> > >> _______________________________________________
> > >> Matplotlib-users mailing list
> > >> Matplotlib-users@lists.sourceforge.net
> > >> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
> > >
> > > --
> > > NEU: FreePhone - kostenlos mobil telefonieren und surfen!
> > > Jetzt informieren: http://www.gmx.net/de/go/freephone
> > > _______________________________________________
> > > SciPy-User mailing list
> > > SciPy-User@...177...
> > > http://mail.scipy.org/mailman/listinfo/scipy-user
> > >
> >
> > We have added a new feature to do just that in the development branch,
> > but it should be fairly trivial to do with existing releases of
> > matplotlib. Just create a figure object and use its figtitle to hold
> > the expression and then save the figure.
>
> It might be trivial but how to remove the axis/plot then and crop the
> extend of the eps?
>
> I tried:
>
> plt.figure()
>
plt.title(r'$F(x)=p*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}$',
> fontsize=20)
> plt.show()
>
> /j
>
>
Use figtext instead. I did the following and it looked fine to me:
plt.figure()
plt.figtext(0.1, 0.5,
r'$F(x)=p*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}$',
fontsize=20)
plt.show()
thats working nearly perfect, I would just need to crop the display extend resp. the white space from the eps around...any option/idea?
/j
···
On Mon, May 16, 2011 at 10:21 AM, Johannes Radinger > <JRadinger@...1843...>wrote:
> > >> On Mon, May 16, 2011 at 08:21, Johannes Radinger <JRadinger@...1843...> > > > wrote:
I hope that helps!
Ben Root
--
NEU: FreePhone - kostenlos mobil telefonieren und surfen!
Jetzt informieren: http://www.gmx.net/de/go/freephone
Try setting bbox_inches=‘tight’ in the call to savefig. With bbox_inches=‘tight’, you can then specify the ‘pad_inches’ kwarg to indicate how much padding to put around the tight bounding box. This should work, however some older version of matplotlib might not check the figure text objects for calculating the tightest bounding box. In that case, the way that I typically autocrop my eps files is to convert it into a pdf file and use pdfcrop and then convert it back to eps (assuming you have a standard linux install). Here is the chain of commands I typically use on my Fedora machine:
epstopdf mathtext.eps --outfile=mathtext.temp.pdf
pdfcrop --margins ‘15 2 15 2’ --clip mathtext.temp.pdf mathtext.cropped.pdf
pdftops mathtext.cropped.pdf mathtext.cropped.eps
You can adjust margins to your tastes, and the names of the files are fairly arbitrary.
I hope that helps!
Ben Root
···
On Mon, May 16, 2011 at 11:22 AM, Johannes Radinger <JRadinger@…1843…> wrote:
-------- Original-Nachricht --------
Datum: Mon, 16 May 2011 10:59:34 -0500
Von: Benjamin Root <ben.root@…1304…>
CC: matplotlib-users@lists.sourceforge.net
Betreff: Re: [Matplotlib-users] use matplotlib to produce mathathematical expression only
On Mon, May 16, 2011 at 10:21 AM, Johannes Radinger > > > <JRadinger@…1843…>wrote:
-------- Original-Nachricht --------
Datum: Mon, 16 May 2011 09:49:24 -0500
Von: Benjamin Root <ben.root@…1304…>
Betreff: Re: [Matplotlib-users] [SciPy-User] use matplotlib to produce
mathathematical expression only
-------- Original-Nachricht --------
Datum: Mon, 16 May 2011 08:28:49 -0500
Von: Robert Kern <robert.kern@…287…>
An: SciPy Users List <scipy-user@…177…>
Betreff: Re: [Matplotlib-users] [SciPy-User] use matplotlib to
produce
mathathematical expression only
On Mon, May 16, 2011 at 08:21, Johannes Radinger <JRadinger@…1843…> > > > > > wrote:
Hello,
I want to produce a eps file of following mathematical
expression:
r’$F(x)=p*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}$’
is it possible to somehow missuse matplotlib for that to produce
only
the function without any other plot things? Or is there a better
python
library within scipy? I don’t want to install the complete latex
libraries just
for producing this single eps file.
Check out mathtex. It is matplotlib’s TeX parsing engine and
renderer
broken out into a separate library:
I also thought about mathtex but don’t know how to use my
mathematical
expression without a plot of axis etc. any suggestions? I just want to
have
the formated math expression as eps and I don’t know how to do it,
still
/johannes
Also, please send matplotlib questions just to the matplotlib list.
Thanks.
Robert Kern
"I have come to believe that the whole world is an enigma, a
harmless
enigma that is made terrible by our own mad attempt to interpret it
as
though it had an underlying truth."
– Umberto Eco
Achieve unprecedented app performance and reliability
What every C/C++ and Fortran developer should know.
Learn how Intel has extended the reach of its next-generation tools
to help boost performance applications - inlcuding clusters.
http://p.sf.net/sfu/intel-dev2devmay
Matplotlib-users mailing list
Matplotlib-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/matplotlib-users
NEU: FreePhone - kostenlos mobil telefonieren und surfen!
Jetzt informieren: http://www.gmx.net/de/go/freephone
SciPy-User mailing list
SciPy-User@…1836…77…
http://mail.scipy.org/mailman/listinfo/scipy-user
We have added a new feature to do just that in the development branch,
but it should be fairly trivial to do with existing releases of
matplotlib. Just create a figure object and use its figtitle to hold
the expression and then save the figure.
It might be trivial but how to remove the axis/plot then and crop the
extend of the eps?
I tried:
plt.figure()
plt.title(r’$F(x)=p*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}$’,
fontsize=20)
plt.show()
/j
Use figtext instead. I did the following and it looked fine to me:
plt.figure()
plt.figtext(0.1, 0.5,
r’$F(x)=p*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}$’,
fontsize=20)
plt.show()
thats working nearly perfect, I would just need to crop the display extend resp. the white space from the eps around…any option/idea?
/j
<https://github.com/matplotlib/matplotlib/commit/44d3cf8cb883a85c325459165b6ed120219c7451>Below is the new function that was recently added to the development version (that Benjamin was referring to). It should work to include it in your own code and should work for the past few releases of matplotlib. It gets around the need for any external tools for cropping etc since the tight bounding box is calculated within matplotlib.
Mike
def math_to_image(s, filename_or_obj, prop=None, dpi=None, format=None):
"""
Given a math expression, renders it in a closely-clipped bounding
box to an image file.
*s*
A math expression. The math portion should be enclosed in
dollar signs.
*filename_or_obj*
A filepath or writable file-like object to write the image data
to.
*prop*
If provided, a FontProperties() object describing the size and
style of the text.
*dpi*
Override the output dpi, otherwise use the default associated
with the output format.
*format*
The output format, eg. 'svg', 'pdf', 'ps' or 'png'. If not
provided, will be deduced from the filename.
"""
from matplotlib import figure
# backend_agg supports all of the core output formats
from matplotlib.backends import backend_agg
if prop is None:
prop = FontProperties()
parser = MathTextParser('path')
width, height, depth, _, _ = parser.parse(s, dpi=72, prop=prop)
fig = figure.Figure(figsize=(width / 72.0, height / 72.0))
fig.text(0, depth/height, s, fontproperties=prop)
backend_agg.FigureCanvasAgg(fig)
fig.savefig(filename_or_obj, dpi=dpi, format=format)
return depth
···
On 05/16/2011 12:36 PM, Benjamin Root wrote:
-------- Original-Nachricht --------
> Datum: Mon, 16 May 2011 10:59:34 -0500
> Von: Benjamin Root <ben.root@…1304… <mailto:ben.root@…1304…>>
> CC: matplotlib-users@lists.sourceforge.net
<mailto:matplotlib-users@lists.sourceforge.net>
> Betreff: Re: [Matplotlib-users] use matplotlib to produce
mathathematical expression only
>
> >
> > -------- Original-Nachricht --------
> > > Datum: Mon, 16 May 2011 09:49:24 -0500
> > > Von: Benjamin Root <ben.root@…1304… <mailto:ben.root@…1304…>>
> > > An: "matplotlib-users@lists.sourceforge.net
<mailto:matplotlib-users@lists.sourceforge.net>" <
> > matplotlib-users@lists.sourceforge.net
<mailto:matplotlib-users@lists.sourceforge.net>>
> > > Betreff: Re: [Matplotlib-users] [SciPy-User] use matplotlib
to produce
> > mathathematical expression only
> >
> > > >
> > > > -------- Original-Nachricht --------
> > > >> Datum: Mon, 16 May 2011 08:28:49 -0500
> > > >> Von: Robert Kern <robert.kern@…287…
<mailto:robert.kern@…287…>>
> > > >> An: SciPy Users List <scipy-user@…177…
<mailto:scipy-user@…177…>>
> > > >> CC: matplotlib-users@lists.sourceforge.net
<mailto:matplotlib-users@lists.sourceforge.net>
> > > >> Betreff: Re: [Matplotlib-users] [SciPy-User] use
matplotlib to
> produce
> > > mathathematical expression only
> > > >
> > > >> On Mon, May 16, 2011 at 08:21, Johannes Radinger > <JRadinger@…1843… <mailto:JRadinger@…1843…>> > > > > wrote:
> > > >> > Hello,
> > > >> >
> > > >> > I want to produce a eps file of following mathematical
> expression:
> > > >> >
> > > >>
> > >
> >
>
r'$F(x)=p*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}$'
> > > >> >
> > > >> > is it possible to somehow missuse matplotlib for that
to produce
> > only
> > > >> the function without any other plot things? Or is there a
better
> > python
> > > >> library within scipy? I don't want to install the
complete latex
> > > libraries just
> > > >> for producing this single eps file.
> > > >>
> > > >> Check out mathtex. It is matplotlib's TeX parsing engine and
> renderer
> > > >> broken out into a separate library:
> > > >>
> > > >
> > > > I also thought about mathtex but don't know how to use my
> mathematical
> > > expression without a plot of axis etc. any suggestions? I
just want to
> > have
> > > the formated math expression as eps and I don't know how to
do it,
> still
> > > after reading in the matplotlib-manual.
> > > >
> > > > /johannes
> > > >
> > > >>
> > > >> Also, please send matplotlib questions just to the
matplotlib list.
> > > >> Thanks.
> > > >>
> > > >> –
> > > >> Robert Kern
> > > >>
> > > >> "I have come to believe that the whole world is an enigma, a
> harmless
> > > >> enigma that is made terrible by our own mad attempt to
interpret it
> as
> > > >> though it had an underlying truth."
> > > >> – Umberto Eco
> > > >>
> > >
> >
>
------------------------------------------------------------------------------
> > > >> Achieve unprecedented app performance and reliability
> > > >> What every C/C++ and Fortran developer should know.
> > > >> Learn how Intel has extended the reach of its
next-generation tools
> > > >> to help boost performance applications - inlcuding clusters.
> > > >> http://p.sf.net/sfu/intel-dev2devmay
> > > >> _______________________________________________
> > > >> Matplotlib-users mailing list
> > > >> Matplotlib-users@lists.sourceforge.net
<mailto:Matplotlib-users@lists.sourceforge.net>
> > > >> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
> > > >
> > > > –
> > > > NEU: FreePhone - kostenlos mobil telefonieren und surfen!
> > > > Jetzt informieren: http://www.gmx.net/de/go/freephone
> > > > _______________________________________________
> > > > SciPy-User mailing list
> > > > SciPy-User@…177… <mailto:SciPy-User@…177…>
> > > > http://mail.scipy.org/mailman/listinfo/scipy-user
> > > >
> > >
> > > We have added a new feature to do just that in the
development branch,
> > > but it should be fairly trivial to do with existing releases of
> > > matplotlib. Just create a figure object and use its
figtitle to hold
> > > the expression and then save the figure.
> >
> > It might be trivial but how to remove the axis/plot then and
crop the
> > extend of the eps?
> >
> > I tried:
> >
> > plt.figure()
> >
>
plt.title(r'$F(x)=p*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}$',
> > fontsize=20)
> > plt.show()
> >
> > /j
> >
> Use figtext instead. I did the following and it looked fine to me:
>
> plt.figure()
> plt.figtext(0.1, 0.5,
>
r'$F(x)=p*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}$',
> fontsize=20)
> plt.show()
>
thats working nearly perfect, I would just need to crop the
display extend resp. the white space from the eps around...any
option/idea?
/j
Try setting bbox_inches='tight' in the call to savefig. With bbox_inches='tight', you can then specify the 'pad_inches' kwarg to indicate how much padding to put around the tight bounding box. This should work, however some older version of matplotlib might not check the figure text objects for calculating the tightest bounding box. In that case, the way that I typically autocrop my eps files is to convert it into a pdf file and use pdfcrop and then convert it back to eps (assuming you have a standard linux install). Here is the chain of commands I typically use on my Fedora machine:
epstopdf mathtext.eps --outfile=mathtext.temp.pdf
pdfcrop --margins '15 2 15 2' --clip mathtext.temp.pdf mathtext.cropped.pdf
pdftops mathtext.cropped.pdf mathtext.cropped.eps
You can adjust margins to your tastes, and the names of the files are fairly arbitrary.
I hope that helps!
Ben Root
------------------------------------------------------------------------------
Achieve unprecedented app performance and reliability
What every C/C++ and Fortran developer should know.
Learn how Intel has extended the reach of its next-generation tools
to help boost performance applications - inlcuding clusters.
http://p.sf.net/sfu/intel-dev2devmay
_______________________________________________
Matplotlib-users mailing list
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--
Michael Droettboom
Science Software Branch
Space Telescope Science Institute
Baltimore, Maryland, USA
-------- Original-Nachricht --------
Datum: Mon, 16 May 2011 11:36:18 -0500
Von: Benjamin Root <ben.root@...1304...>
CC: matplotlib-users@lists.sourceforge.net
Betreff: Re: [Matplotlib-users] use matplotlib to produce mathathematical expression only
>
> -------- Original-Nachricht --------
> > Datum: Mon, 16 May 2011 10:59:34 -0500
> > Von: Benjamin Root <ben.root@...1304...>
> > CC: matplotlib-users@lists.sourceforge.net
> > Betreff: Re: [Matplotlib-users] use matplotlib to produce
mathathematical
> expression only
>
> >
> > >
> > > -------- Original-Nachricht --------
> > > > Datum: Mon, 16 May 2011 09:49:24 -0500
> > > > Von: Benjamin Root <ben.root@...1304...>
> > > > An: "matplotlib-users@lists.sourceforge.net" <
> > > matplotlib-users@lists.sourceforge.net>
> > > > Betreff: Re: [Matplotlib-users] [SciPy-User] use matplotlib to
> produce
> > > mathathematical expression only
> > >
> > > > >
> > > > > -------- Original-Nachricht --------
> > > > >> Datum: Mon, 16 May 2011 08:28:49 -0500
> > > > >> Von: Robert Kern <robert.kern@...287...>
> > > > >> An: SciPy Users List <scipy-user@...177...>
> > > > >> CC: matplotlib-users@lists.sourceforge.net
> > > > >> Betreff: Re: [Matplotlib-users] [SciPy-User] use matplotlib to
> > produce
> > > > mathathematical expression only
> > > > >
> > > > >> > Hello,
> > > > >> >
> > > > >> > I want to produce a eps file of following mathematical
> > expression:
> > > > >> >
> > > > >>
> > > >
> > >
> >
>
r'$F(x)=p*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}$'
> > > > >> >
> > > > >> > is it possible to somehow missuse matplotlib for that to
produce
> > > only
> > > > >> the function without any other plot things? Or is there a
better
> > > python
> > > > >> library within scipy? I don't want to install the complete
latex
> > > > libraries just
> > > > >> for producing this single eps file.
> > > > >>
> > > > >> Check out mathtex. It is matplotlib's TeX parsing engine and
> > renderer
> > > > >> broken out into a separate library:
> > > > >>
> > > > >> http://code.google.com/p/mathtex/
> > > > >
> > > > > I also thought about mathtex but don't know how to use my
> > mathematical
> > > > expression without a plot of axis etc. any suggestions? I just
want
> to
> > > have
> > > > the formated math expression as eps and I don't know how to do it,
> > still
> > > > after reading in the matplotlib-manual.
> > > > >
> > > > > /johannes
> > > > >
> > > > >
> > > > >>
> > > > >> Also, please send matplotlib questions just to the matplotlib
> list.
> > > > >> Thanks.
> > > > >>
> > > > >> --
> > > > >> Robert Kern
> > > > >>
> > > > >> "I have come to believe that the whole world is an enigma, a
> > harmless
> > > > >> enigma that is made terrible by our own mad attempt to
interpret
> it
> > as
> > > > >> though it had an underlying truth."
> > > > >> -- Umberto Eco
> > > > >>
> > > > >>
> > > >
> > >
> >
>
------------------------------------------------------------------------------
> > > > >> Achieve unprecedented app performance and reliability
> > > > >> What every C/C++ and Fortran developer should know.
> > > > >> Learn how Intel has extended the reach of its next-generation
> tools
> > > > >> to help boost performance applications - inlcuding clusters.
> > > > >> http://p.sf.net/sfu/intel-dev2devmay
> > > > >> _______________________________________________
> > > > >> Matplotlib-users mailing list
> > > > >> Matplotlib-users@lists.sourceforge.net
> > > > >> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
> > > > >
> > > > > --
> > > > > NEU: FreePhone - kostenlos mobil telefonieren und surfen!
> > > > > Jetzt informieren: http://www.gmx.net/de/go/freephone
> > > > > _______________________________________________
> > > > > SciPy-User mailing list
> > > > > SciPy-User@...177...
> > > > > http://mail.scipy.org/mailman/listinfo/scipy-user
> > > > >
> > > >
> > > > We have added a new feature to do just that in the development
> branch,
> > > > but it should be fairly trivial to do with existing releases of
> > > > matplotlib. Just create a figure object and use its figtitle to
hold
> > > > the expression and then save the figure.
> > >
> > > It might be trivial but how to remove the axis/plot then and crop
the
> > > extend of the eps?
> > >
> > > I tried:
> > >
> > > plt.figure()
> > >
> >
>
plt.title(r'$F(x)=p*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}$',
> > > fontsize=20)
> > > plt.show()
> > >
> > > /j
> > >
> > >
> > Use figtext instead. I did the following and it looked fine to me:
> >
> > plt.figure()
> > plt.figtext(0.1, 0.5,
> >
>
r'$F(x)=p*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}$',
> > fontsize=20)
> > plt.show()
> >
>
>
> thats working nearly perfect, I would just need to crop the display
extend
> resp. the white space from the eps around...any option/idea?
>
>
> /j
>
>
Try setting bbox_inches='tight' in the call to savefig. With
bbox_inches='tight', you can then specify the 'pad_inches' kwarg to
indicate
how much padding to put around the tight bounding box. This should work,
however some older version of matplotlib might not check the figure text
objects for calculating the tightest bounding box.
Hej,
plt.figure()
plt.figtext(0.01, 0.5,r'$F(x)=p*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}*e^{-\frac{1}{2}*(\frac{x-m}{s1})}$', fontsize=26)
#plt.show()
plt.savefig("testplot.eps", bbox_inches='tight')
but get following error:
plt.savefig("testplot.eps", bbox_inches='tight')
File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/matplotlib/pyplot.py", line 363, in savefig
return fig.savefig(*args, **kwargs)
File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/matplotlib/figure.py", line 1084, in savefig
self.canvas.print_figure(*args, **kwargs)
File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/matplotlib/backend_bases.py", line 1891, in print_figure
bbox_inches = self.figure.get_tightbbox(renderer)
File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/matplotlib/figure.py", line 1212, in get_tightbbox
_bbox = Bbox.union([b for b in bb if b.width!=0 or b.height!=0])
File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/matplotlib/transforms.py", line 675, in union
assert(len(bboxes))
AssertionError
I work with python 2.6.6 and matplotlib 1.0.1 on Mac OS X 10.6.6
/j
In that case, the way
···
On Mon, May 16, 2011 at 11:22 AM, Johannes Radinger > <JRadinger@...1843...>wrote:
> > On Mon, May 16, 2011 at 10:21 AM, Johannes Radinger > > > <JRadinger@...1843...>wrote:
> > > > On Monday, May 16, 2011, Johannes Radinger <JRadinger@...1843...> > wrote:
> > > > >> On Mon, May 16, 2011 at 08:21, Johannes Radinger < > > JRadinger@...1843...> > > > > > wrote:
that I typically autocrop my eps files is to convert it into a pdf file
and
use pdfcrop and then convert it back to eps (assuming you have a standard
linux install). Here is the chain of commands I typically use on my
Fedora
machine:
epstopdf mathtext.eps --outfile=mathtext.temp.pdf
pdfcrop --margins '15 2 15 2' --clip mathtext.temp.pdf
mathtext.cropped.pdf
pdftops mathtext.cropped.pdf mathtext.cropped.eps
You can adjust margins to your tastes, and the names of the files are
fairly
arbitrary.
I hope that helps!
Ben Root
--
NEU: FreePhone - kostenlos mobil telefonieren und surfen!
Jetzt informieren: http://www.gmx.net/de/go/freephone
There have been some bugs fixed with bbox_inches=‘tight’, but I couldn’t remember if they happened after or before the v1.0.1 release. My guess is that it happened after.
I am glad the other function worked for you.
Ben Root
···
On Tue, May 17, 2011 at 2:58 AM, Johannes Radinger <JRadinger@…1843…> wrote:
-------- Original-Nachricht --------
Datum: Mon, 16 May 2011 11:36:18 -0500
Von: Benjamin Root <ben.root@…1304…>
Betreff: Re: [Matplotlib-users] use matplotlib to produce mathathematical expression only
On Mon, May 16, 2011 at 11:22 AM, Johannes Radinger > > > <JRadinger@…1843…>wrote:
-------- Original-Nachricht --------
Datum: Mon, 16 May 2011 10:59:34 -0500
Von: Benjamin Root <ben.root@…1304…>
Betreff: Re: [Matplotlib-users] use matplotlib to produce
mathathematical
expression only
On Mon, May 16, 2011 at 10:21 AM, Johannes Radinger > > > > > <JRadinger@…3607…3…>wrote:
-------- Original-Nachricht --------
Datum: Mon, 16 May 2011 09:49:24 -0500
Von: Benjamin Root <ben.root@…1304…>
Betreff: Re: [Matplotlib-users] [SciPy-User] use matplotlib to
produce
mathathematical expression only
On Monday, May 16, 2011, Johannes Radinger <JRadinger@…1843…> > > > wrote:
-------- Original-Nachricht --------
Datum: Mon, 16 May 2011 08:28:49 -0500
Von: Robert Kern <robert.kern@…287…>
An: SciPy Users List <scipy-user@…177…>
Betreff: Re: [Matplotlib-users] [SciPy-User] use matplotlib to
produce
mathathematical expression only
On Mon, May 16, 2011 at 08:21, Johannes Radinger < > > > > JRadinger@…1843…> > > > > > > > wrote:
Hello,
I want to produce a eps file of following mathematical
expression:
r’$F(x)=p*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}$’
is it possible to somehow missuse matplotlib for that to
produce
only
the function without any other plot things? Or is there a
better
python
library within scipy? I don’t want to install the complete
latex
libraries just
for producing this single eps file.
Check out mathtex. It is matplotlib’s TeX parsing engine and
renderer
broken out into a separate library:
I also thought about mathtex but don’t know how to use my
mathematical
expression without a plot of axis etc. any suggestions? I just
want
to
have
the formated math expression as eps and I don’t know how to do it,
still
/johannes
Also, please send matplotlib questions just to the matplotlib
list.
Thanks.
Robert Kern
"I have come to believe that the whole world is an enigma, a
harmless
interpret
it
as
though it had an underlying truth."
– Umberto Eco
Achieve unprecedented app performance and reliability
What every C/C++ and Fortran developer should know.
Learn how Intel has extended the reach of its next-generation
tools
to help boost performance applications - inlcuding clusters.
http://p.sf.net/sfu/intel-dev2devmay
Matplotlib-users mailing list
Matplotlib-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/matplotlib-users
NEU: FreePhone - kostenlos mobil telefonieren und surfen!
Jetzt informieren: http://www.gmx.net/de/go/freephone
SciPy-User mailing list
SciPy-User@…177…
http://mail.scipy.org/mailman/listinfo/scipy-user
We have added a new feature to do just that in the development
branch,
but it should be fairly trivial to do with existing releases of
matplotlib. Just create a figure object and use its figtitle to
hold
the expression and then save the figure.
It might be trivial but how to remove the axis/plot then and crop
the
extend of the eps?
I tried:
plt.figure()
plt.title(r’$F(x)=p*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}$’,
fontsize=20)
plt.show()
/j
Use figtext instead. I did the following and it looked fine to me:
plt.figure()
plt.figtext(0.1, 0.5,
r’$F(x)=p*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}$’,
fontsize=20)
plt.show()
thats working nearly perfect, I would just need to crop the display
extend
resp. the white space from the eps around…any option/idea?
/j
Try setting bbox_inches=‘tight’ in the call to savefig. With
bbox_inches=‘tight’, you can then specify the ‘pad_inches’ kwarg to
indicate
how much padding to put around the tight bounding box. This should work,
however some older version of matplotlib might not check the figure text
objects for calculating the tightest bounding box.
Hej,
plt.figure()
plt.figtext(0.01, 0.5,r’$F(x)=p*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}+(1-p)*\frac{1}{s1\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-m}{s1})}$’, fontsize=26)
#plt.show()
plt.savefig(“testplot.eps”, bbox_inches=‘tight’)
but get following error:
plt.savefig(“testplot.eps”, bbox_inches=‘tight’)
File “/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/matplotlib/pyplot.py”, line 363, in savefig
return fig.savefig(*args, **kwargs)
File “/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/matplotlib/figure.py”, line 1084, in savefig
self.canvas.print_figure(*args, **kwargs)
File “/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/matplotlib/backend_bases.py”, line 1891, in print_figure
bbox_inches = self.figure.get_tightbbox(renderer)
File “/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/matplotlib/figure.py”, line 1212, in get_tightbbox
_bbox = Bbox.union([b for b in bb if b.width!=0 or b.height!=0])
File “/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/matplotlib/transforms.py”, line 675, in union
assert(len(bboxes))
AssertionError
I work with python 2.6.6 and matplotlib 1.0.1 on Mac OS X 10.6.6
/j | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8128021359443665, "perplexity": 12891.97002487741}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-51/segments/1575540529006.88/warc/CC-MAIN-20191210205200-20191210233200-00541.warc.gz"} |
https://proofwiki.org/wiki/Category:Spence%27s_Function | # Category:Spence's Function
Jump to navigation Jump to search
This category contains results about Spence's Function.
Spence's function, also known as the dilogarithm, is a special case of the polylogarithm, defined for $z \in \C$ by the integral:
$\displaystyle \operatorname {Li}_2 \paren z = -\int_0^z \frac {\Ln \paren {1 - t} } t \rd t$
where:
$\displaystyle \int_0^z$ is an integral across the straight line in the complex plane connecting $0$ and $z$.
$\Ln$ is the principal branch of the complex natural logarithm.
## Pages in category "Spence's Function"
The following 2 pages are in this category, out of 2 total. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9488058686256409, "perplexity": 964.5650527433332}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-16/segments/1585370521574.59/warc/CC-MAIN-20200404073139-20200404103139-00276.warc.gz"} |
http://www.wiki.gis.com/wiki/index.php/Latitude | # Latitude
Latitude, usually denoted by the Greek letter phi (φ) gives the location of a place on Earth (or other planetary body) north or south of the equator. Lines of Latitude are the horizontal lines shown running east-to-west on maps (particularly so in the Mercator projection). Technically, latitude is an angular measurement in degrees (marked with °) ranging from 0° at the equator (low latitude) to 90° at the poles (90° N or +90° for the North Pole and 90° S or −90° for the South Pole). The latitude is approximately the angle between straight up at the surface (the zenith) and the sun at an equinox. The complementary angle of a latitude is called the colatitude.
## Circles of latitude
All locations of a given latitude are collectively referred to as a circle of latitude or line of latitude or parallel, because they are coplanar, and all such planes are parallel to the equator. Lines of latitude other than the Equator are approximately small circles on the surface of the Earth; they are not geodesics since the shortest route between two points at the same latitude involves a path that bulges toward the nearest pole, first moving farther away from and then back toward the equator (see great circle).
A specific latitude may then be combined with a specific longitude to give a precise position on the Earth's surface (see satellite navigation system).
### Important named circles of latitude
Besides the equator, four other lines of latitude are named because of the role they play in the geometrical relationship with the Earth and the Sun:
Only at latitudes between the Tropics is it possible for the sun to be at the zenith. Only north of the Arctic Circle or south of the Antarctic Circle is the midnight sun possible.
The reason that these lines have the values that they do lies in the axial tilt of the Earth with respect to the sun, which is 23° 26′ 21.41″.
Note that the Arctic Circle and Tropic of Cancer are colatitudes, since the sum of their angles is 90°—similarly for the Antarctic Circle and Tropic of Capricorn.
## Subdivisions
A degree is divided into 60 minutes. One minute can be further divided into 60 seconds. An example of a latitude specified in this way is 13°19'43″ N (for greater precision, a decimal fraction can be added to the seconds). An alternative representation uses only degrees and minutes, where the seconds are expressed as a decimal fraction of minutes: the above example would be expressed as 13°19.717' N. Degrees can also be expressed singularly, with both the minutes and seconds incorporated as a decimal number and rounded as desired (decimal degree notation): 13.32861° N. Sometimes, the north/south suffix is replaced by a negative sign for south (−90° for the South Pole).
## Effect of latitude
Average temperatures vary strongly with latitude.
A region's latitude has a great effect on its climate and weather (see Effect of sun angle on climate). Latitude more loosely determines tendencies in polar auroras, prevailing winds, and other physical characteristics of geographic locations.
Researchers at Harvard's Center for International Development (CID) found in 2001 that only three tropical economies — Hong Kong, Singapore, and Taiwan — were classified as high-income by the World Bank, while all countries within regions zoned as temperate had either middle- or high-income economies. [1] The validity of the Harvard report may be questioned because a different threshold is used for the tropical regions and the World Bank list fails to include Qatar's, United Arab Emirates', and Kuwait's economies. Further, countries such as Brazil have far better incomes than much of the Former Soviet Union and Iron Curtain states[citation needed].
## Elliptic parameters
Because most planets (including Earth) are ellipsoids of revolution, or spheroids, rather than spheres, both the radius and the length of arc varies with latitude. This variation requires the introduction of elliptic parameters based on an ellipse's angular eccentricity, $o\!\varepsilon\,\!$ (which equals $\arccos\left(\frac{b}{a}\right)\,\!$, where $a\;\!$ and $b\;\!$ are the equatorial and polar radii; $\sin^2(o\!\varepsilon)\,\!$ is the first eccentricity squared, ${e^2}\,\!$; and $2\sin^2\left(\frac{o\!\varepsilon}{2}\right)\;\!$ or $1-\cos(o\!\varepsilon)\,\!$ is the flattening, ${f}\,\!$). Utilized in creating the integrands for curvature is the inverse of the principal elliptic integrand, $E'\,\!$:
$n'(\phi)=\frac{1}{E'(\phi)} =\frac{1}{\sqrt{1-(\sin(\phi)\sin(o\!\varepsilon))^2}};\,\!$
\begin{align} M(\phi)&=a\cdot\cos^2(o\!\varepsilon)n'^3(\phi) =\frac{(ab)^2}{\Big((a\cos(\phi))^2+(b\sin(\phi))^2\Big)^{3/2}};\\ N(\phi)&=a{\cdot}n'(\phi) =\frac{a^2}{\sqrt{(a\cos(\phi))^2+(b\sin(\phi))^2}}.\end{align}\,\!
## Degree length
On Earth, the length of an arcdegree of north–south latitude difference, $\scriptstyle{\Delta\phi}\,\!$, is about 60 nautical miles, 111 kilometres or 69 statute miles at any latitude. The length of an arcdegree of east-west longitude difference, $\scriptstyle{\cos(\phi)\Delta\lambda}\,\!$, is about the same at the equator as the north-south, reducing to zero at the poles.
In the case of a spheroid, a meridian and its anti-meridian form an ellipse, from which an exact expression for the length of an arcdegree of latitude difference is:
$\frac{\pi}{180^\circ}M(\phi);\,\!$
This radius of arc (or "arcradius") is in the plane of a meridian, and is known as the meridional radius of curvature, $M\,\!$.[2][3]
Similarly, an exact expression for the length of an arcdegree of longitude difference is:
$\frac{\pi}{180^\circ}\cos(\phi)N(\phi);\,\!$
The arcradius contained here is in the plane of the prime vertical, the east-west plane perpendicular (or "normal") to both the plane of the meridian and the plane tangent to the surface of the ellipsoid, and is known as the normal radius of curvature, $N\,\!$.[2][3]
Along the equator (east-west), $N\;\!$ equals the equatorial radius. The radius of curvature at a right angle to the equator (north-south), $M\;\!$, is 43 km shorter, hence the length of an arcdegree of latitude difference at the equator is about 1 km less than the length of an arcdegree of longitude difference at the equator. The radii of curvature are equal at the poles where they are about 64 km greater than the north-south equatorial radius of curvature because the polar radius is 21 km less than the equatorial radius. The shorter polar radii indicate that the northern and southern hemispheres are flatter, making their radii of curvature longer. This flattening also 'pinches' the north-south equatorial radius of curvature, making it 43 km less than the equatorial radius. Both radii of curvature are perpendicular to the plane tangent to the surface of the ellipsoid at all latitudes, directed toward a point on the polar axis in the opposite hemisphere (except at the equator where both point toward Earth's center). The east-west radius of curvature reaches the axis, whereas the north-south radius of curvature is shorter at all latitudes except the poles.
The WGS84 ellipsoid, used by all GPS devices, uses an equatorial radius of 6378137.0 m and an inverse flattening, (1/f), of 298.257223563, hence its polar radius is 6356752.3142 m and its first eccentricity squared is 0.00669437999014.[4] The more recent but little used IERS 2003 ellipsoid provides equatorial and polar radii of 6378136.6 and 6356751.9 m, respectively, and an inverse flattening of 298.25642.[5] Lengths of degrees on the WGS84 and IERS 2003 ellipsoids are the same when rounded to six significant digits. An appropriate calculator for any latitude is provided by the U.S. government's National Geospatial-Intelligence Agency (NGA).[6]
of curvature
$M\;\!$
Surface distance
per 1° change
in latitude
of curvature
$N\;\!$
Surface distance
per 1° change
in longitude
6335.44 km 110.574 km 6378.14 km 111.320 km
15° 6339.70 km 110.649 km 6379.57 km 107.551 km
30° 6351.38 km 110.852 km 6383.48 km 96.486 km
45° 6367.38 km 111.132 km 6388.84 km 78.847 km
60° 6383.45 km 111.412 km 6394.21 km 55.800 km
75° 6395.26 km 111.618 km 6398.15 km 28.902 km
90° 6399.59 km 111.694 km 6399.59 km 0.000 km
## Types of latitude
With a spheroid that is slightly flattened by its rotation, cartographers refer to a variety of auxiliary latitudes to precisely adapt spherical projections according to their purpose.
For planets other than Earth, such as Mars, geographic and geocentric latitude are called "planetographic" and "planetocentric" latitude, respectively. Most maps of Mars since 2002 use planetocentric coordinates.
### Common "latitude"
In common usage, "latitude" refers to geodetic or geographic latitude $\phi\,\!$ and is the angle between the equatorial plane and a line that is normal to the reference ellipsoid, which approximates the shape of Earth to account for flattening of the poles and bulging of the equator. This value usually differs from the geocentric latitude.
The expressions following assume elliptical polar sections and that all sections parallel to the equatorial plane are circular. Geographic latitude (with longitude) then provides a Gauss map. As defined earlier in this article, $o\!\varepsilon\,\!$ is the angular eccentricity of a meridian.
### Reduced latitude
• On a spheroid, lines of reduced or parametric latitude, $\beta\,\!$, form circles whose radii are the same as the radii of circles formed by the corresponding lines of latitude on a sphere with radius equal to the equatorial radius of the spheroid.
$\beta=\arctan\Big(\cos(o\!\varepsilon)\tan(\phi)\Big) = \arctan\Bigg(\frac{b}{a}\tan(\phi)\Bigg);\,\!$
### Authalic latitude
• Authalic latitude, $\xi\,\!$, gives an area-preserving transform to the sphere.
$\widehat{S}^2(\phi)=\frac{1}{2}b^2\left(\sin(\phi)n'^2(\phi)+\frac{\ln\bigg(n'(\phi)\Big(1+\sin(\phi)\sin(o\!\varepsilon)\Big)\bigg)}{\sin(o\!\varepsilon)}\right);\,\!$
\begin{align}\xi&=\arcsin\!\left(\frac{\widehat{S}^2(\phi)}{\widehat{S}^2(90^\circ)}\right),\\ &=\arcsin\!\left(\frac{\sin(\phi)\sin(o\!\varepsilon)n'^2(\phi)+\ln\Big(n'(\phi)\big(1+\sin(\phi)\sin(o\!\varepsilon)\big)\Big)}{\sin(o\!\varepsilon)\sec^2(o\!\varepsilon)+\ln\Big(\sec(o\!\varepsilon)\big(1+\sin(o\!\varepsilon)\big)\Big)}\right);\end{align}\,\!
### Rectifying latitude
• Rectifying latitude, $\mu\,\!$, is the surface distance from the equator, scaled so the pole is 90°, but involves elliptic integration:
$\mu=\frac{\;\int_{0}^\phi\;M(\theta)\,d\theta}{\frac{2}{\pi}\int_{0}^{90^\circ}M(\phi)\,d\phi} =\frac{\pi}{2}\cdot\frac{\;\int_{0}^\phi\;n'^3(\theta)\,d\theta}{\int_{0}^{90^\circ}n'^3(\phi)\,d\phi};\,\!$
### Conformal latitude
• Conformal latitude, $\chi\,\!$, gives an angle-preserving (conformal) transform to the sphere.
$\chi=2\cdot\arctan\left(\sqrt{\frac{1+\sin(\phi)}{1-\sin(\phi)}\cdot\left(\frac{1-\sin(\phi)\sin(o\!\varepsilon)}{1+\sin(\phi)\sin(o\!\varepsilon)}\right)^{\!\!\sin(o\!\varepsilon)}}^{\color{white}|}\;\right)-\frac{\pi}{2};\;\!$
### Geocentric latitude
• The geocentric latitude, $\psi\,\!$, is the angle between the equatorial plane and a line from the center of Earth.
$\psi=\arctan\Big(\cos^2(o\!\varepsilon)\tan(\phi)\Big) = \arctan\Big((b/a)^2\tan(\phi)\Big).\;\!$
It is the size of the central angle between the equator and the point of interest, as measured along a meridian. This value usually differs from the geographic latitude, as so:
Illustration of geographic and geocentric latitudes.
### Astronomical latitude
A more obscure measure of latitude is the astronomical latitude, which is the angle between the equatorial plane and the normal to the geoid (ie a plumb line). It originated as the angle between horizon and pole star. It differs from the geodetic latitude only slightly, due to the slight deviations of the geoid from the reference ellipsoid.
Astronomical latitude is not to be confused with declination, the coordinate astronomers use to describe the locations of stars north/south of the celestial equator (see equatorial coordinates), nor with ecliptic latitude, the coordinate that astronomers use to describe the locations of stars north/south of the ecliptic (see ecliptic coordinates).
### Palaeolatitude
Continents move over time, due to continental drift, taking whatever fossils and other features of interest they may have with them. Particularly when discussing fossils, it's often more useful to know where the fossil was when it was laid down, than where it is when it was dug up: this is called the palæolatitude of the fossil. The Palæolatitude can be constrained by palæomagnetic data. If tiny magnetisable grains are present when the rock is being formed, these will align themselves with Earth's magnetic field like compass needles. A magnetometer can deduce the orientation of these grains by subjecting a sample to a magnetic field, and the magnetic declination of the grains can be used to infer the latitude of deposition.
### Comparison of selected types
The following plot shows the differences between the types of latitude. The data used are found in the table following the plot. Please note that the values in the table are in minutes, not degrees, and the plot reflects this as well. Also observe that the conformal symbols are hidden behind the geocentric due to being very close in value. Finally it is important to mention also that these differences don't mean that the use of one specific latitude will necessarily cause more distortions than the other (the real fact is that each latitude type is optimized for achieving a different goal).
Approximate difference from geographic latitude ("Lat")
Lat
$\phi\,\!$
Reduced
$\phi-\beta\,\!$
Authalic
$\phi-\xi\,\!$
Rectifying
$\phi-\mu\,\!$
Conformal
$\phi-\chi\,\!$
Geocentric
$\phi-\psi\,\!$
0.00′ 0.00′ 0.00′ 0.00′ 0.00′
1.01′ 1.35′ 1.52′ 2.02′ 2.02′
10° 1.99′ 2.66′ 2.99′ 3.98′ 3.98′
15° 2.91′ 3.89′ 4.37′ 5.82′ 5.82′
20° 3.75′ 5.00′ 5.62′ 7.48′ 7.48′
25° 4.47′ 5.96′ 6.70′ 8.92′ 8.92′
30° 5.05′ 6.73′ 7.57′ 10.09′ 10.09′
35° 5.48′ 7.31′ 8.22′ 10.95′ 10.96′
40° 5.75′ 7.66′ 8.62′ 11.48′ 11.49′
45° 5.84′ 7.78′ 8.76′ 11.67′ 11.67′
50° 5.75′ 7.67′ 8.63′ 11.50′ 11.50′
55° 5.49′ 7.32′ 8.23′ 10.97′ 10.98′
60° 5.06′ 6.75′ 7.59′ 10.12′ 10.13′
65° 4.48′ 5.97′ 6.72′ 8.95′ 8.96′
70° 3.76′ 5.01′ 5.64′ 7.52′ 7.52′
75° 2.92′ 3.90′ 4.39′ 5.85′ 5.85′
80° 2.00′ 2.67′ 3.00′ 4.00′ 4.01′
85° 1.02′ 1.35′ 1.52′ 2.03′ 2.03′
90° 0.00′ 0.00′ 0.00′ 0.00′ 0.00′
### Corrections for altitude
Line IH is normal to the spheroid representing the Earth (colored orange) at point H. The angle it forms with the equator (represented by line CA) corresponds to the point's geodetic latitude.
When converting from geodetic ("common") latitude to other types of latitude, corrections must be made for altitude for systems which do not measure the angle from the normal of the spheroid. For example, in the figure at right, point H (located on the surface of the spheroid) and point H' (located at some greater elevation) have different geocentric latitudes (angles β and γ respectively), even though they share the same geodetic latitude (angle α). Note that the flatness of the spheroid and elevation of point H' in the image is significantly greater than what is found on the Earth, exaggerating the errors inherent in such calculations if left uncorrected. Note also that the reference ellipsoid used in the geodetic system is itself just an approximation of the true geoid, and therefore introduces its own errors, though the differences are less severe. (See Astronomical latitude, above.) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 41, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.875256359577179, "perplexity": 2069.3693558061336}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-33/segments/1659882573172.64/warc/CC-MAIN-20220818063910-20220818093910-00797.warc.gz"} |
http://gate-exam.in/cs/CSE-GATE-2016-Question-16 | # GATE Papers >> CSE >> 2016 >> Question No 16
Question No. 16
Consider the Boolean operator # with the following properties:
$x\#0\;=\;x,\;x\#1\;=\;\overline x,\;x\#x\;=\;0\;and\;x\#\overline x\;=1.$ Then $x#y$ is equivalent to
##### Answer : (A) $x\overset-y+\overset-xy$
Solution of Question No 16 of GATE 2016 CSE Paper
x y x#y 0 0 0 0 1 1 1 0 1 1 1 0
$\begin{array}{l}x\#0=x\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;...1\\x\#1=\overline x\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;...2\\x\#x=0\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;...3\\x\#\overline x=1\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;...4\\x\#y=x\overline y+\overline xy\end{array}$ | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9798259735107422, "perplexity": 2474.0974021081447}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-50/segments/1606141185851.16/warc/CC-MAIN-20201126001926-20201126031926-00409.warc.gz"} |
https://gateoverflow.in/2014/gate-cse-2014-set-2-question-48 | 9,709 views
The probability that a given positive integer lying between $1$ and $100$ (both inclusive) is NOT divisible by $2$, $3$ or $5$ is ______ .
Answer - $0.26$
Number of integers divisible by $2 = 50$
Number of integers divisible by $3 = 33$
Number of integers divisible by $5 = 20$
Number of integers divisible by $2$ and $3 = 16$
Number of integers divisible by $2$ and $5 = 10$
Number of integers divisible by $3$ and $5 = 6$
Number of integers divisible by $2$ and $3$ and $5 = 3$
Total numbers divisible by $2$ or $3$ or $5 = 50 + 33 + 20 -16 -10 - 6 + 3 = 74$
Total number not divisible by $2$ or $3$ or $5 = 26$
Probability $= 0.26$ [EDIT]
What is the meaning of not divisible by 2,3 or 5?
1. (Not div by 2) or (not div by 3) or ( not div by 5)
2. ( Not div by 2) and ( not div by 3 ) and ( not div by 5)
option 2. ( Not div by 2) and ( not div by 3 ) and ( not div by 5)
In case anyone has doubt whether to take $ceil$ or $floor$, remember we are finding number of numbers divisible by $x$ (say $3$) among a set of $100$ no.s. So $100/3 = 33.33$
If we take $34$ no.s then it’s wrong because we don’t have $34$ numbers. We actually have $33$ only. Hence $floor$ value is always taken.
This is Brute Force method but takes very less time because we just need to check number is not div by 2,3 or 5.
Total no of possible outcomes N(s) = 100
N(e)=Number's not divisible by (2 OR 3 OR 5) = (Not Div by 2 AND Not Div by 3 Not Div by 5 ) /// Demargon's law
N(e) = {1,7,11,13,17,19,23,29,31,37,41,43,47,49,53,59,61,67,71,73,77,79,83,89,91,97} = 26
Prob = N(e) / N(s) = 26/100 = 0.26
by
### 1 comment
In examination setting,this takes long time and moreover, using this approach one may not be confident
There are total 100 numbers, out of which
50 numbers are divisible by 2,
33 numbers are divisible by 3,
20 numbers are divisible by 5
Following are counted twice above
16 numbers are divisible by both 2 and 3
10 numbers are divisible by both 2 and 5
6 numbers are divisible by both 3 and 5
Following is counted thrice above
3 numbers are divisible by all 2, 3 and 5
So total numbers divisible by 2, 3 and 5 are = = 50 + 33 + 20 - 16 - 10 - 6 + 3 = 103 - 29 = 74 So probability that a number is number is not divisible by 2, 3 and 5 = (100 - 74)/100 = 0.26
https://math.stackexchange.com/a/1034611
I think this one is a better way to find number of divisors. Please check and confirm if its good or not. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.31127437949180603, "perplexity": 385.3935265329491}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030335059.43/warc/CC-MAIN-20220928020513-20220928050513-00190.warc.gz"} |
https://aviation.stackexchange.com/questions/30269/how-can-i-calculate-the-force-on-the-nose-gear-at-landing/31398 | # How can I calculate the force on the nose gear at landing?
How can I calculate the force applied on nose gear during landing as nose gear touches the runway little after the landing gear? I understand force calculations in this question but I think it applies on main gear. How is the force on the nose gear calculated?
• It depends on the angular speed of (de)rotation, i.e. how much quickly the fuselage rotates from landing attitude to horizontal... – mins Jul 24 '16 at 13:43
• I think you want to start with energy then find the force. – user3344003 Jul 24 '16 at 17:38
• F = ma, the hard part is figuring out how much mass is on the nose wheel. Ideally at touchdown its not more than a minor percentage of the total aircraft weight, as the goal when landing (small aircraft at least) is to keep the nose wheel up until it comes down gently on its own. – Ron Beyer Jul 25 '16 at 1:49
• I calculated the mass on the nose wheel but i am not been able to calculate the acceleration when nose wheel touches down the runway – Umair Jul 25 '16 at 4:51
Calculating the loads on the nose and main landing gear isn't really different. The answer you linked is a highly simplified approach you should be able to use for the nose landing gear too, but I will provide a "less simplified" approach to calculate the vertical forces. The braking force is already greatly described there.
A simplified approach
First you need to know the impact speed and the spring and damping characteristic of your landing gear.
At touch down there are three possible cases:
• Main landing gear touches the ground first. Then the airplane rotates down with an angular speed $\omega_L$. The impact speed of you nose landing gear is therefore $$V_{Impact} = \omega_L \cdot d$$ $d$: distance between the main and the nose landing gear.
• Nose landing gear touches the ground first. (For now empty, if I get time I'll write about it later)
• Both landing gears touch the ground at the same time. For a glide angle $\gamma$ the impact speed will be: $$V_{Impact} = V\cdot \sin(\gamma)$$ $V$: airplane speed
The stiffness ($k$) and damping characteristic ($c$) of the landing gear depend mainly on the suspension and the tires used. Tires inflated with a wrong pressure can be really dangerous as they can increase the load on the landing gear.
Putting this data together into a mass spring damper model like in the image
gives you an equation for the nose landing gear movement: $$m\cdot \ddot{x}+c\cdot \dot{x}+k\cdot x = -m\cdot g$$ For the reduced mass $m$ in the model use the mass carried by the nose landing gear. $$m = LM \cdot \frac{d-d_{CG}}{d}$$ $d_{CG}$: distance from the nose landing gear to the center of gravity
$LM$: aircraft landing mass
$g$: gravity constant
The initial condition for the differential equation is: $$\dot{x}(t=0) = -V_{Impact}$$ The impact occurs at $t=0$.
To calculate the force on the nose landing gear you just have tofind the maximum acceleration and add the static and dynamic loads: $$F_{max}=-m\cdot g -m\cdot \ddot{x}_{max}$$
Real world problems
While the calculations above works for really stiff wings, in reality the loads on the landing gear will be (probably) higher. This is due to the inertial forces of the oscillating aircraft structure.
If you don't understand where this forces come from try moving your arms up and down while standing: you will feel small forces on your feet. Now repeat the experiment with two 60t heavy wings as in the A380 and you'll see that the forces are not neglectable. And were do the oscillations come from? The same as with a guitar string: after a small excitation (plucking the strings/ landing impact) the structure (guitar string/ aircraft wings) begins to oscillate.
What other things doesn't this model take into account? Coupling between nose and main landing gear, rotation inertia, nonlinear tire characteristics,...
In order to calculate the force, you should start with an estimation of the angular momentum as the nose sinks and the wheel contacts the ground. That angular momentum am becomes zero as soon as the oleo leg is compressed to its maximum stroke, but that takes a measurable time, from first contact of the front wheel with the ground till the extreme compression of the oleo leg. If you assume that the force f on the oleo leg is constant along the compression stroke, and know the time t it takes, then:
f = am/t
Of course, it's only a rough estimate, but better than nothing...
In order to calculate am, you'll need to know the mass of the plane, its moment of inertia when turning on the main wheels, and the angular velocity of that movement. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7367008328437805, "perplexity": 926.6828385646819}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-10/segments/1581875145839.51/warc/CC-MAIN-20200223185153-20200223215153-00486.warc.gz"} |
http://bims.iranjournals.ir/article_373.html | # Upper bounds on the solutions to n = p+m^2
Document Type: Research Paper
Author
Abstract
ardy and Littlewood conjectured that every large integer $n$ that is not a square is the sum of a prime and a square. They believed that the number $mathcal{R}(n)$ of such representations for $n = p+m^2$ is asymptotically given by
begin{equation*}
mathcal{R}(n) sim frac{sqrt{n}}{log n}prod_{p=3}^{infty}left(1-frac{1}{p-1}left(frac{n}{p}right)right),
end{equation*}
where $p$ is a prime, $m$ is an integer, and $left(frac{n}{p}right)$ denotes the Legendre symbol. Unfortunately, as we will later point out, this conjecture is difficult to prove and not emph{all} integers that are nonsquares can be represented as the sum of a prime and a square. Instead in this paper we prove two upper bounds for $mathcal{R}(n)$ for $n le N$. The first upper bound applies to emph{all} $n le N$. The second upper bound depends on the possible existence of the Siegel zero, and assumes its existence, and applies to all $N/2 < n le N$ but at most $ll N^{1-delta_1}$ of these integers, where $N$ is a sufficiently large positive integer and \$0
Keywords
### History
• Receive Date: 16 January 2010
• Revise Date: 01 June 2010
• Accept Date: 01 June 2010 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.974337637424469, "perplexity": 289.31214441020813}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-43/segments/1570986696339.42/warc/CC-MAIN-20191019141654-20191019165154-00429.warc.gz"} |
https://www.math.ucdavis.edu/research/seminars?talk_id=2875 | # Mathematics Colloquia and Seminars
A path (cycle) containing every vertex in a graph is called a Hamilton path (Hamilton cycle, respectively). Hamilton cycles have been studied extensively in graph theory for their own sake, because of connections with the four color problem, and the travelling salesman problem. A graph is called vertex-transitive if for any pair of vertices u and v there exists an automorphism mapping u to v. In 1969, Lovasz asked whether every finite connected vertex-transitive graph has a Hamilton path, thus tying together two seemingly unrelated concepts: traversability and symmetry of graphs. With the exception of the complete graph on two vertices, only four connected vertex-transitive graphs that do not have a Hamilton cycle are known to exist. These four graphs are the Petersen graph, the Coxeter graph and the two graphs obtained from them by replacing each vertex by a triangle. The fact that none of these four graphs is a Cayley graph has led to a folklore conjecture that every Cayley graph has a Hamilton cycle. (A Cayley graph is a graph whose automorphism group admits a regular subgroup.) Both of these two problems are still open. However, a considerable amount of partial results are known. In this talk an overview of these results will be introduced. A special emphasis will be given to recent results concerning the existence of Hamilton cycles in cubic Cayley graphs arising from groups having $(2,s,3)$-presentation. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6560060381889343, "perplexity": 165.29162776902177}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-31/segments/1627046152144.92/warc/CC-MAIN-20210726183622-20210726213622-00477.warc.gz"} |
http://koreascience.or.kr/search.page?keywords=Element&pageSize=10&pageNo=0 | • Title, Summary, Keyword: Element
### Formulation Method for Solid-to-Beam Transition Finite Elements
• Im, Jang-Gwon;Song, Dae-Han;Song, Byeong-Ho
• Journal of Mechanical Science and Technology
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• v.15 no.11
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• pp.1499-1506
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• 2001
• Various transition elements are used in general for the effective finite element analysis of complicated mechanical structures. In this paper, a solid-to-beam transition finite element, which can b e used for connecting a C1-continuity beam element to a continuum solid element, is proposed. The shape functions of the transition finite element are derived to meet the compatibility condition, and a transition element equation is formulated by the conventional finite element procedure. In order to show the effectiveness and convergence characteristics of the proposed transition element, numerical tests are performed for various examples. As a result of this study, following conclusions are obtained. (1) The proposed transition element, which meets the compatibility of the primary variables, exhibits excellent accuracy. (2) In case of using the proposed transition element, the number of nodes in the finite element model may be considerably reduced and the model construction becomes more convenient. (3) This formulation method can be applied to the usage of higher order elements.
### An assumed-stress hybrid element for static and free vibration analysis of folded plates
• Darilmaz, Kutlu
• Structural Engineering and Mechanics
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• v.25 no.4
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• pp.405-421
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• 2007
• A four-node hybrid stress element for analysing orthotropic folded plate structures is presented. The formulation is based on Hellinger-Reissner variational principle. The element is developed by combining a hybrid plane stress element and a hybrid plate element. The proposed element has six degree of freedom per node and permits an easy connection to other type of elements. An equilibrated stress field in each element and inter element compatible boundary displacement field are assumed independently. Static and free vibration analyses of folded plates are carried out on numerical examples to show that the validity and efficiency of the present element.
### A new 3D interface element for three dimensional finite element analysis of FRP strengthened RC beams
• Kohnehpooshi, O.;Noorzaei, J.;Jaafar, M.S.;Saifulnaz, M.R.R.
• Interaction and multiscale mechanics
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• v.4 no.4
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• pp.257-271
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• 2011
• The analysis of interfacial stresses in structural component has been the subject of several investigations but it still requires more effort and studies. In this study a general three-dimensional interface element has been formulated for stress and displacement analyses in the interfacial area between two adjacent plate bending element and brick element. Interface element has 16 nodes with 5 degrees of freedom (DOF) in each node adjacent to plate bending element and 3 DOF in each node adjacent to brick element. The interface element has ability to transfer three translations from each side of interface element and two rotations in the side adjacent to the plate element. Stiffness matrix of this element was formulated and implemented in three-dimensional finite element code. Application of this element to the reinforced concrete (RC) beam strengthened with fiber reinforced polymer (FRP) including variation of deflection, slip between plate and concrete, normal and shear stresses distributions in FRP plates have been verified using experimental and numerical work of strengthened RC beams carried out by some researchers. The results show that this interface element is effective and can be used for structural component with these types of interface elements.
### A hybrid 8-node hexahedral element for static and free vibration analysis
• Darilmaz, Kutlu
• Structural Engineering and Mechanics
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• v.21 no.5
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• pp.571-590
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• 2005
• An 8 node assumed stress hexahedral element with rotational degrees of freedom is proposed for static and free vibration analyses. The element formulation is based directly on an 8-node element. This direct formulation requires fewer computations than a similar element that is derived from an internal 20-node element in which the midside degrees of freedom are eliminated by expressing them in terms of displacements and rotations at corner nodes. The formulation is based on Hellinger-Reissner variational principle. Numerical examples are presented to show the validity and efficiency of the present element for static and free vibration analysis.
### Development of a flat shell element by using the hybrid Trefftz plane element with drilling D.O.F. and the DKMQ element (면내 회전 자유도가 추가된 hybrid Trefftz 평면 요소와 DKMQ 요소를 이용한 4 절점 평면 셸 요소의 개발)
• 최누리;추연석;이승규;이병채
• Proceedings of the Korean Society of Precision Engineering Conference
• /
• /
• pp.855-859
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• 2004
• We develop a new four-node flat shell element which is accurate, efficient, and suitable to be used on general purpose. The new element has a hybrid Trefftz element with drilling degrees of freedom as a membrane part. We define the two independent displacement field: the internal displacement field that satisfies governing equations in the domain a priori and the boundary displacement field that is usually used as a conventional finite element method. The hybrid Trefftz variational formulation connects these two displacement fields on the boundary of the domain. To add drilling degrees of freedom, we introduce the Allman's quadratic displacement field to the boundary displacement field. As a result, our flat shell element has 6 degrees of freedom per a node. We also use the well-known DKMQ plate bending element for the plate part of the proposed element. The DKMQ element satisfies Mindlin-Reissner‘s plate theory along the edge of the element and gives proper behavior regardless of the thickness. A series of numerical experiments shows that the performance of the new element such as accuracy, rate of convergence, robustness to mesh quality, and so on.
### Comparisons of Elasto-Fiber and Fiber & Bernoulli-Euler reinforced concrete beam-column elements
• Karaton, Muhammet
• Structural Engineering and Mechanics
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• v.51 no.1
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• pp.89-110
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• 2014
• In this study, two beam-column elements based on the Elasto-Fiber element theory for reinforced concrete (RC) element have been developed and compared with each other. The first element is based on Elasto Fiber Approach (EFA) was initially developed for steel structures and this theory was applied for RC element in there and the second element is called as Fiber & Bernoulli-Euler element approach (FBEA). In this element, Cubic Hermitian polynomials are used for obtaining stiffness matrix. The beams or columns element in both approaches are divided into a sub-element called the segment for obtaining element stiffness matrix. The internal freedoms of this segment are dynamically condensed to the external freedoms at the ends of the element by using a dynamic substructure technique. Thus, nonlinear dynamic analysis of high RC building can be obtained within short times. In addition to, external loads of the segment are assumed to be distributed along to element. Therefore, damages can be taken account of along to element and redistributions of the loading for solutions. Bossak-${\alpha}$ integration with predicted-corrected method is used for the nonlinear seismic analysis of RC frames. For numerical application, seismic damage analyses for a 4-story frame and an 8-story RC frame with soft-story are obtained to comparisons of RC element according to both approaches. Damages evaluation and propagation in the frame elements are studied and response quantities from obtained both approaches are investigated in the detail.
### Finite Element Analysis of Sheet Metal Forming Process Using Shell Element (쉘 요소를 이용한 박판성형공정의 유한요소해석)
• Jung Dong-Won;Ko Hyung-Hoon;Lee Chan-Ho;You Ho-Young
• Journal of the Korean Society for Precision Engineering
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• v.23 no.1
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• pp.152-158
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• 2006
• The AutoForm previously used the membrane element and it accomplished sheet metal forming analysis. The membrane analysis has been widely applied to various sheet metal forming processes because of its time effectiveness. However, it is well-known that the membrane analysis can not provide correct information for the processes which have considerable bending effects. In this research experimental results were compared with the analysis results obtained by using the shell element which is applied newly in the AutoForm commercial software. The shell element is a compromise element between continuum element and membrane element. The Finite element method by using shell element is the most efficient numerical method. From this research, it is known that FEA by using shell element can predict accurately the problems happened in actual experimental auto-body panel.
### A Study on the Criterion for Membrane/Shell Mixed Element and Application to the Rigid-Plastic/Elastic-Plastic Finite Element Analysis (박막/쉘 혼합요소의 판별조건과 강소성/탄소성 유한요소해석 적용에 관한 연구)
• Jung, Dong-Won;Yang, Kyoung-Boo
• Journal of Ocean Engineering and Technology
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• v.13 no.2
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• pp.1-10
• /
• 1999
• This study is concerned with the application of new criterion for membrane/shell mixed element in the rigid-plastic finite element analysis and elastic-plastic finite element analysis. The membrane/shell mixed element can be selctively adapted to the pure stretching condition by using membrane or a shell element in the bending effect areas. Thus, membrane/shell mixed element requires a efficient criterion for a distinction between membrane and shell element. In the present study introduce the criterion using the angle of between two element and confirm a generality of criterion from appling the theory to a rigid-plastic and elastic-plastic problems.
### Development of 8-node Flat Shell Element for the Analysis of Folded Plate Structures (절판 구조물의 해석을 위한 8절점 평면 첼 요소의 개발)
• 최창근;한인선
• Proceedings of the Computational Structural Engineering Institute Conference
• /
• /
• pp.234-241
• /
• 1999
• In this study, an improved 8-node flat shell element is presented for the analysis of shell structure, by combining 8-node membrane element with drilling degree-of-freedom and 8-node plate bending element based on the recently presented technique. Firstly, 8-node membrane element designated as CLM8 is presented in this paper. The element has drilling degree-of.freedom in addition to transitional degree-of-freedom. Therefore the element possesses 3 degrees-of-freedom per each node which as well as the improvement of the element behavior, permits an easy connection to other element with rotational degree-of -freedom. Secondly. 8-node flat shell element was composed by adding 8-node Mindlin plate bending element to the membrane element. The behavior of the introduced plate bending element is further improved by combined use of nonconforming displacement modes, selectively reduced integration scheme and assumed shear strain fields. The element passes in the patch test, doesn't show spurious mechanism and doesn't produce shear locking phenomena. Finally, Numerical examples are presented to show the performance of flat shell element developed in the present study.
### Formulation Method of a Solid-To-Beam Transitional Finite Element (연속체-보 천이 유한요소의 구성)
• Park, Woo-Jin;Lim, Jang-Keun
• Proceedings of the KSME Conference
• /
• /
• pp.351-356
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• 2000
• Various transition elements are generally used for the effective analysis of a complicated mechanical structure. In this paper, a solid-to-beam transition finite element which connects a continuum element and a $c^1-continuity$ beam element each other is proposed. The shape functions of the transition finite elements, which a 8-noded hexahedral solid element fur 3D analysis and a 4-noded quadrilateral plane element fur 2D analysis are connected to a Euler's beam element, are explicitely formulated. In order to show the effectiveness and convergence characteristics of the proposed transition elements. numerical tests are performed for various examples and their results are compared with those obtained by other methods. As the result of this study. following conclusions are obtained: (1)The proposed transition finite elements show the monotonic convergence characteristics because of having used the compatible displacement folds. (2)As being used the transition element in the finite element analysis, the finite element modelings are more convenient and the analysis results are more accurate because of the formulation characteristies of the Euler's beam element. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.614768385887146, "perplexity": 2521.7177838509842}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-40/segments/1600400265461.58/warc/CC-MAIN-20200927054550-20200927084550-00304.warc.gz"} |
http://mathhelpforum.com/algebra/26750-perimeter-triangle-huh-print.html | # perimeter of a triangle?? huh??
• January 24th 2008, 11:53 AM
nikkivue
perimeter of a triangle?? huh??
:confused: what is the peimeter of a triangle which sides measure 6, 8, and 10 inches? :confused: all this stuff is giving me a headache! (Doh)
• January 24th 2008, 12:02 PM
colby2152
Quote:
Originally Posted by nikkivue
:confused: what is the peimeter of a triangle which sides measure 6, 8, and 10 inches? :confused: all this stuff is giving me a headache! (Doh)
The perimeter of an area is the sum of all of its sides, so in this situation the perimeter is $6+8+10=24$.
• February 26th 2008, 07:55 PM
maleena90
Quote:
Originally Posted by nikkivue
:confused: what is the peimeter of a triangle which sides measure 6, 8, and 10 inches? :confused: all this stuff is giving me a headache! (Doh) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 1, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.81471848487854, "perplexity": 2257.6939243043744}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-52/segments/1418802765616.69/warc/CC-MAIN-20141217075245-00072-ip-10-231-17-201.ec2.internal.warc.gz"} |
https://iforest.sisef.org/contents/?id=ifor2147-011 | ## Can bark stripping cause red heartwood formation in beech stems?
iForest - Biogeosciences and Forestry, Volume 11, Issue 2, Pages 251-258 (2018)
doi: https://doi.org/10.3832/ifor2147-011
Research Articles
Injuries to standing trees caused by logging and the subsequent changes in biochemical composition and anatomy of affected tissues lead to wood quality loss, thus lowering the commercial value of roundwood. In this study, we investigated the influence of various factors that could help mitigate or prevent the spread of infections in the stem caused by injuries. A total of 112 beech logs (tree age: 42-143 years) from ten forest stands at three different sites in central Slovakia were examined, and the extent of discolouration and decay zones in each stem was measured, along with cambial age, stem diameter, injury width, and injury closure period. The results showed that the width of physiologically active wet sapwood and the width of the inactive dehydrated zone in the stem are important factors influencing red heartwood formation. We found no significant differences in the extent of discolouration and decay among different stands and sites. Stem diameter and injury width did significantly affect the penetration of infection through sapwood, and red heartwood formation was significantly affected by cambial age and injury width, while stand age, site slope, beech proportion in the stand and injury closure did not show any significant effect. Binary logistic models were applied to assess the probability of pathogen penetration through sapwood into the stem dehydrated zone as a function of injury width and stem diameter, as well as the probability that this could lead to red heartwood formation based on injury width and cambial age of beech stems.
# Introduction
Mechanical injury to tree stems caused by forest thinning and tree felling often determines the devaluation of beech roundwood. Bark stripping activates a variety of physiological defence reactions, which modify the biochemical characteristics of the affected tissues in the living trees. Discolouration is a visible symptom reflecting the presence of polyphenols in the affected tissue, which are probably due to the interaction between the enzymes of pioneer pathogens and the atmospheric oxygen ([1]). This indicates that exposure to air and the initial colonisation by microorganisms have already taken place. Simultaneously, polyphenols also protect the threatened tissues against further invasion of pathogens and retard the decaying process of wood caused by fungi ([23]).
Sapwood is the outer zone of the stem which has an effective defence system to protect the vital functions of transport and reserves, restrict air embolism during the later stages, and limit the spread of pathogens ([7]). However, aging and maturation in some diffuse-porous species does not cause genetically-controlled metabolic changes leading to the transformation from sapwood to heartwood in the centre of the stem ([32]). The central non-coloured zone of the stem, known as “ripewood” ([22]) or “dehydrated zone” (especially in beech - [34]), is free of tyloses and polyphenolic compounds. These tissues show a reduced moisture content and a limited number of vital parenchyma cells ([15], [22]). Several developmental and environmental factors affect the formation and size of the dehydrated zone ([34], [4], [10], [25]); however, the age of the tree is a dominant factor in this process ([22], [3]).
Injury of a living stem enables pathogens to enter through the injured surface and penetrate deeper into the surrounding xylem tissues. Faced with the risk of drying out and an expanding microbial infection, the sapwood efficiently defends its high moisture content, by forming tyloses in the vessels and triggering primary biochemical reactions. The capacity for defence is predominantly influenced by the physiological state of the tree ([8], [33]). If the pathogens entering through an injury overcome the strongest anatomical and biochemical barriers of the sapwood, a massive longitudinal spread of discolouration and decay can affect the dehydrated zone. The presence of discoloured wood in the middle of a stem, initiated by an injury, reduces the ratio of white coloured wood and thus lowers its commercial value ([2]). Apart from terms such as “discoloured wood” and “decay wood” ([32]), the terms “red heartwood”, “wound heartwood”, “splash heartwood” and “abnormal heartwood” ([27]) are frequently used to describe this phenomenon.
Discolouration and decay in the centre of beech stems (hereafter referred to as red heartwood) are predominantly caused by infection and oxygen penetrating through broken and dead branches ([21], [4], [19], [18], [40], [29], [35], [36]). However, there is a lack of detailed information on whether bark stripping caused by logging can lead to red heartwood formation in beech.
The aim of this work was to evaluate: (i) if there is a link between the internal extent of discolouration and decay in the stem (in radial direction) and the external features on the injured surface; (ii) if there is a link between the extent of discolouration and decay in the stem (in radial direction) and different environmental conditions; (iii) what is the probability of discolouration and decay, caused by air penetration and microbial invasion (in radial direction) spreading through the sapwood into the central part of the stem; and (iv) what is the probability that the microbial infection entering the injury and penetrating into the dehydrated zone through sapwood is capable of causing extensive red heartwood formation.
# Material and methods
## Site characteristics and sample material
Sample material was obtained from 10 different forest stands at three diffent locations belonging to the Forest Enterprise of the Technical University in Zvolen, Slovakia, situated in the orographic unit of Kremnické vrchy (48° 35′ 32.6″ N, 19° 03′ 45.0″ E - Tab. 1). The occurrence of fungi in the investigated forests was determined according to the phytopathological methodology of permanent monitoring plots (10 × 10 m) in combination with random selection of transects with an area of 100 × 10 m ([13] - Tab. S1 in Supplementary material). Trees were felled continuously during the vegetation and dormant period from February 2012 to March 2013. A total of 248 sample beech trees aged from 42 to 143 years with DBH ranging from 22.7 to 61.6 cm, were obtained. This equates to approximately 25 trees per forest stand. Subsequently, the trees were cut into logs (3-5 m in length - Fig. 1a).
Tab. 1 - Main characteristics of the sampled stands at the three investigated sites. (Aa): Abies alba; (Ag): Alnus glutinosa; (Apl): Acer platanoides; (Aps): Acer pseudoplatanus; (Fe): Fraxinus excelsior; (Cb): Carpinus betulus; (Pa): Picea abies; (Ps): Pinus sylvestris; (Qp): Quercus petraea; (Qp): Quercus cerris; (Um): Ulmus montana; (*): concerning only beech.
Characteristics Site Mláčik Bukovina Trnie
Stand 813 B 737 352 806(4) 744A(1) 626 B 203(1) 427 A 545 339
Mean age (years)* 70 110 115 135 160 110 130 65 90 110
Mean DBH (cm)* 26 42 56 42 42 48 47 25 34 55
Mean height (m)* 23 32 32 29 26 28 30 24 29 29
Beech proportion (%) 80 51 49 50 9 75 15 85 55 51
Other species (%) Cb-20 Aa-22,
Fe-16,
Aps-6,
Pa-5
Qp-41,
Qc-10
Cb-50 Aps-43,
Fe-25,
Aa-13,
Apl-10
Cb-15,
Qp-5,
Qc-3,
Ps-2
Qp-50,
Aa-33,
Pa-2
Qp-5,
Cb -5,
Ag-5
Qp-25,Pa-15,
Aa-5
Aps-29,Apl-12,
Cb-8
Site quality* medium good good poor poor medium medium good good medium
Altitude (m a.s.l.) 300-450 675-825 430-460 500-650 680-800 475-555 590-690 380-460 445-590 500-580
Exposure SE SE E E SE NE SE NE E E
Slope (%) 40 35 15 45 30 15 25 30 60 40
Thinning date 07-2012 03-2013 01-2013 02-2012 04-2012 07-2012 09-2012 02-2012 05-2012 09-2012
Number of fell trees 23 28 25 23 27 22 26 24 26 24
Number of injuriies 16 8 7 9 11 10 12 17 11 11
Fig. 1 - (a) Scheme of stem cutting. (b) Graphical representation of the independent and dependent variables measured in this study (b).
## Measurement of sapwood and dehydrated zone width at the time of felling
From each log, a 10 cm thick cross-section was cut (1063 cross sections in total - Fig. 1a). Within 30 minutes, a central dehydrated zone appeared on the freshly felled cross-sections, whilst the wetter outer zone was considered to be sapwood. Both zones, together with the stem diameter (measured from all the cross-sections along the tree height), were measured at the time of felling. Linear regression relationships between sapwood width and stem diameter, as well as between dehydrated zone width and stem diameter, were then determined (Fig. 2). Following these steps, the logs were used for estimating sapwood and dehydrated zone width at the time of injury closure.
Fig. 2 - Relationship between stem diameter and sapwood width (red points) or dehydrated zone width (blue points).
## Measurement of injury-related variables
A total of 112 logs with visible wound scars were selected and sectioned through the middle of the injury (Fig. 1a). All injuries were caused by thinning operations, and were located randomly along the entire length of the tree stems. The length of injuries ranged from 0.12 to 0.86 m. The centripetal discolouration depth and the decay depth on the log cross sections were determined as dependent variables, while the cambial age, stem diameter (both obtained at the time of injury closure), injury width and injury closure period were determined as independent variables (Fig. 1b). Cambial age and injury closure period were counted, whereas the remaining injury characteristics were measured. Cambial age denotes the total number of annual growth rings up to injury closure, whereas the injury closure period denotes the number of annual growth rings, starting with the origin of the injury and ending by closure of injury by lateral calluses.
## Estimation of sapwood and dehydrated zone width at the time of injury closure
Stem diameters at the time of injury closure were measured on the faces of the cross-sectioned discs that contained discoloured and decayed zones only. Then, the probable sapwood width and dehydrated zone width at the time of injury closure were estimated (Fig. 1b), according to a linear regression relationship (Fig. 2).
## Estimation of sapwood penetration
A discrete variable was designed to indicate if discolouration or decay have exceeded the sapwood boundary in each stem. The ratio r1 between the discolouration depth and the sapwood width, and the ratio r2 between the decay depth and the sapwood width, were calculated according to the following formulae (eqn. 1):
$${r_1} = {\frac{DiD} {SW} } \\{r_2} = {\frac{DeD} {SW}}$$
where DiD is the discolouration depth (cm), DeD is the decay depth (cm), SW is the sapwood width (cm). If ri >1, the sapwood boundary has been exceeded and the value “yes” was assigned to the discrete variable. If ri <1, the sapwood boundary was not overcome and the discrete variable was given the value “not”.
## Estimation of red heartwood occurrence and size
The presence of red heartwood was assessed visually. Injuries with only wedge-shaped discoloured zones and unstained central dehydrated zones (Fig. 3a) were classified as injuries that did not cause the formation of red heartwood (discrete value “not”). On the other hand, injuries with wedge-shaped discoloured zones, centripetally expanding in width, and associated with central round discoloured zones (red heartwood - Fig. 3b) were classified as injuries that had a causal relationship with the formation of red heartwood (discrete value “yes”). Abnormally large, irregular-shaped heartwood exceeding the dehydrated zone was also included in the category of red heartwood (Fig. 3c).
Fig. 3 - Classification of injuries: (a) Injuries not causing red heartwood formation; (b) Injuries causing red heartwood formation; (c) Injuries causing abnormal heartwood formation. (SWZ): sapwood zone (a wet marginal zone visible on freshly-felled cross sections of the tree trunks); (DZ): dehydrated zone (a paler and drier central part of the stem visible on freshly-felled cross sections of older tree trunks); (DiZ): discoloured zone (a wedge-shaped and pale brown-coloured zone in sapwood, sometimes exceeding dehydrated zone boundary); (DeZ): decayed zone (a wedge-shaped, dark brown or white-coloured zone localized in marginal parts of discoloured zones); (RHW): red heartwood (smaller central round-shaped and reddish brown-coloured zone formed in dehydrated zone); (AHW): abnormal heartwood (a large irregular-shaped and brown-coloured zone exceeding of dehydrated zone boundary and deeply extending into the sapwood zone).
The dimension of red heartwood was assessed by measuring its width in two perpendicular directions. The size of red heartwood was then calculated as the average value from the two measurements.
## Statistical analysis
Descriptive statistics were calculated for each measured variable. Multiple linear regression analysis was applied using the following model (eqn. 2):
$${y_{i} } = {b_0 } + {b_1} {x_1} + {b_2} {x_2} + {b_3} {x_3} + {b_4} {x_4}$$
where yi represents the dependent variables (y1: discolouration depth; y2: decay depth), b0 is the intercept, b1-b4 are the regression coefficients, and x1-x4 are the predictors (independent variables, x1: cambial age, in years; x2: stem diameter, in cm; x3: injury width, in cm; x4: injury closure period, in years).
The correlation coefficients of the dependent variables with the predictor variables were calculated, and the significance of correlation and regression coefficients was tested for all regressions. Multiple analysis of variance (ANOVA) and post-hoc Duncan’s test were used to assess possible differences across different forest stands and sites. The software STATISTICA® ver. 10.0 (Stat Soft, Tulsa, OK, USA) was used for all analyses.
The probability of exceeding the sapwood boundary, and the probability of formation of discolouration and decay in the centre of the stem using the investigated factors as predictors were evaluated by binary logistic regression analysis. The binary logistic regression analysis was used to predict the probability of the discrete dependent variable y, which has a non-linear relationship with the linear predictor x. For the final transformation of the dependent variables into a linear one, a logarithm of odds (logit) was calculated. Then, the linear logistic models were described by the equation (eqn. 3):
$$\text{Logit} \left (p_{i,j} \right ) = ln \left (\frac{p}{1-p} \right ) ={b_0 } + {b_1} {x_1} + {b_2} {x_2} + \ldots +{b_7} {x_7}$$
where pi,j is the dependent variable (p1,j is the probability that discolouration exceeds the sapwood boundary, p2,j is the probability that decay exceeds the sapwood boundary; p3,j is the probability of formation of discolouration and decay in the centre of the stem), b0 is the intercept, b1-b7 are the regression coefficients, and x1-x7 are the independent variables (x1: forest age, in years; x2: beech proportion, in %; x3: slope, in %; x4: cambial age, in years; x5: stem diameter, in cm; x6: injury width, in cm; x7: injury closure period, in years).
By means of reverse transformation, a non-linear relationship between the probability and the vector of independent variables was achieved (eqn. 4):
$$p_{i,j} = \frac{{e} ^ { \left ({b_0 } + {b_1} {x_1} + \ldots +{ b_7} {x_7} \right )}} {1+ {e} ^ { \left ({b_0 } + {b_1} {x_1} +\ldots+{ b_7} {x_7} \right )}}$$
The open-source data-mining software Tanagra ver. 1.4.5 (⇒ http://eric.univ-lyon2.fr/~ricco/tanagra/) was used to calculate the odds ratio in the logistic anaysis and test for the statistical significance of the regression coefficients ([26]). The global significance of the logistic models was tested by model fit statistics, model chi-squared test (likelihood ratio) and pseudo-R-like tests. Subsequently, the coefficients of the binary logistic regression models were tested by means of the Wald’s chi-squared test, these being defined as the square root of ratios between the coefficients and their decisive errors ([14]).
The logistic analyses were carried out in two steps. First, all the seven predictors were included in the initial analyses. Subsequently, the initial models were adjusted, discarding the non-significant variables previously included. The adjusted models were then used to assess the relationship between transition probabilities and the significant independent variables, according to eqn. 4.
# Results
## Extent of discolouration and decay
In 48 stems (of the 112 total) only wedge-shaped discoloured zones were present, whilst in the remaining 64 stems, decayed zones were also present (Tab. 2). The average depth of the decayed zones was lower than the average depth of the discoloured zones in all investigated samples; they reached approximately half the depth of the discoloured zones. Also between these variables, a relatively strong linear correlation relationship was found (y = 0.58·x; r = 0.76 - Fig. S1 in Supplementary material). Moreover, stems containing decay zones showed significantly higher average values of injury width and injury closure period. On the contrary, there was no significant difference as far as cambial age and stem diameter were concerned (Tab. 2).
Tab. 2 - Descriptive statistics (mean ± standard deviation) of all variables categorised according to the pathological status of injuries.
Variable Discoloration
zone only
Discoloration
and decay zone
Prob.
(t-test)
Total
cases
n 48 64 - 112
Cambial age 53.9 ± 19.5 59.8 ± 20.9 0.632 50.3 ± 19.3
Stem diameter 26.8 ± 12.6 27.8 ± 9.8 0.064 23.2 ± 10.0
Injury width 4.4 ± 2.6 6.6 ± 3.1 <0.001 5.6 ± 3.1
Injury closure period 5.6 ± 2.6 7.9 ± 3.8 <0.001 6.9 ± 3.5
Discoloration depth 2.3 ± 2.4 6.7 ± 5.7 <0.001 4.8 ± 5.1
Decay depth - 3.7 ± 3.6 - 2.4 ± 3.3
Sapwood width 8.8 ± 4.3 8.6 ± 3.3 0.775 8.7 ± 3.7
Dehydrated zone width 5.3 ± 3.9 5.1 ± 3.0 0.753 5.2 ± 3.4
Despite all combinations of the investigated variables were considered, significant effects were observed only for linear regression models with a maximal of two independent variables (b1 and b2 - Tab. 3). The high values of the correlation coefficients confirmed the relatively strong impact of injury width and injury closure period on the extent of discolouration and decay in radial direction. On the other hand, cambial age and stem diameter had a weak, or no impact. Although their individual effect was weak, some multiple regression models including both variables as predictors showed a relatively strong significance (Tab. 3).
Tab. 3 - Significant linear regression and results of the correlation analysis between the investigated variables and the extent of discoloration and decay. (ns): non significant; (*): p<0.05; (**): p<0.01; (***): p<0.001.
Dependent variable (y) Independent
variables
Intercept Regression
coefficients
Correlation
coefficient (r)
(x1) (x2) b 0 b 1 b 2
Discoloration depth (n=112) Cambial age - ns 0.11*** - 0.401***
Stem diameter - ns 0.15** - 0.289**
Injury width - -1.92** 1.19*** - 0.728***
Injury closure period - -1.27** 0.88*** - 0.610***
Cambial age Injury width -3.36*** 0.04* 1.10*** 0.741***
Cambial age Injury closure period -4.17*** 0.07*** 0.78*** 0.663***
Stem diameter Injury closure period -3.09** 0.09* 0.83*** 0.636***
Decay depth (n=64) Cambial age - ns 0.07** - 0.395**
Injury width - ns 0.74*** - 0.642***
Injury closure period - ns 0.51*** - 0.536***
Cambial age Injury closure period ns 0.05* 0.44*** 0.596***
The extent of discolouration and decay increased with the length of injury closure period. Discolouration depth accelerated with age, whereas decay depth at first also accelerated with age, but only up to 15 years, and afterwards decreased (Tab. S2 in Supplementary material).
## Extent of discolouration and decay across different stands and sites
The extent of discolouration and decay differed only slightly among localities. Higher average values were found only in Bukovina. However, no significant difference in the extent of discolouration nor decay was observed in stems from different sites (Tab. 4). On the other hand, other values that could affect the extent of discolouration and decay were significantly different among the investigated sites.
Tab. 4 - Mean ± standard deviation of the variables considered in the three study sites and significance of their differences after ANOVA.
Variable Mláčik Bukovina Trnie Prob.
n 51 22 39 -
Cambial age 59.3 ± 21.9 67.3 ± 20.7 48.9 ± 14.8 0.0017
Stem diameter 27.6 ± 11.5 32.9 ± 12.7 24.0 ± 7.8 0.0087
Injury width 5.7 ± 2.7 7.2 ± 4.4 4.8 ± 2.4 0.0142
Injury closure period 6.7 ± 3.6 8.5 ± 4.0 6.2 ± 2.9 0.0471
Discolouration depth 4.2 ± 4.5 6.9 ± 7.4 4.4 ± 4.0 0.0950
Decay depth 2.0 ± 3.0 2.7 ± 4.3 2.0 ± 3.1 0.6494
Further analyses revealed a higher extent of discolouration and decay in stands with high average age, low proportion of beech versus other species, and low slope (stands 744 A1 and 203 (1) - Tab. 1, Tab. 5). High values of the extent of discolouration and decay were also found in other older stands, like 339 and 806 (4). Furthermore, injuries were more frequent in stems with higher cambial age in the stands 744 A1 and 203 (1). The average width of injuries was also higher, whilst the injury closure period in all investigated forests varied by only four years (Tab. 5).
Tab. 5 - Descriptive statistics for the studied variables in different forest sites and stands.
Variable Mláčik Bukovina Trnie
813 B 737 352 806 (4) 744 A1 626 B 203 (1) 427 A 545 339
n 16 8 7 9 11 10 12 17 11 11
Cambial age 39.1±12.5 58.0±17.7 66.0±16.8 62.3±14.2 82.9±17.2 59.4±18.3 73.8±21.0 42.3±11.7 46.5±13.4 61.6±13.3
Stem diameter 19.7±6.9 25.0±6.9 33.2±7.3 28.3±9.9 37.1±14.8 30.8±13.2 34.7±12.5 22.6±7.3 22.0±6.7 28.0±8.8
Injury width 4.5±2.0 5.2±2.2 3.9±1.4 7.1±3.4 7.6±2.6 5.8±4.4 8.3±4.2 4.5±1.9 4.9±3.1 5.0±2.4
Injury closure period 5.8±2.7 8.1±5.4 5.1±1.8 7.8±4.3 7.4±3.2 7.2±3.5 9.6±4.3 6.1±2.3 6.6±4.1 6.1±2.4
Discoloration depth 2.3±2.1 4.2±3.5 3.5±5.1 5.3±4.9 6.7±6.1 3.7±4.6 9.6±8.3 3.5±2.9 3.8±3.1 6.2±5.6
Decay depth 1.0±1.9 1.7±2.6 0.9±1.5 2.3±2.2 4.2±4.6 0.6±1.2 4.5±5.1 1.0±1.9 2.1±2.8 3.3±4.5
## Probability of exceeding sapwood width
The analysis of probabilities confirmed that only some of the investigated factors had a significant effect on the exceeding of discolouration and decay through the sapwood in the dehydrated zone. Globally-significant logistic models showed significant coefficients only for two predictors, namely stem diameter and injury width, whereas other independent factors, such as forest age, beech proportion, slope, cambial age, and injury closure period, did not show any significant effect (Tab. S3 and Tab. S4 in Supplementary material). Therefore, the final equation describing the transition probability of discolouration (p1) was defined as follows (eqn. 5):
$$p_1 = \frac{e^{(-1.9 - 0.13 x_1 + 0.79 x_2)}} {1+ {e}^{(-1.9 - 0.13 x_1 + 0.79 x_2 )}}$$
while the final equation describing the transition probability of decay (p2) was as follows (eqn. 6):
$$p_2 = \frac{e^{(-3.18 - 0.11 x_1 + 0.56 x_2 )}} {1+ e^{(-3.18 - 0.11 {x_1} + 0.56 {x_2} )}}$$
where x1 is the stem diameter and x2 is the unjury width in both the above equations.
By increasing the stem diameter, the average value of the odds to exceed the sapwood decreases by only 1.14 times (1:0.88) in the case of discolouration, and 1.12 times (1:0.89) in the case of decay. On the other hand, the increase in width of the injury raises the average value of the odds by 2.21 times (2.21:1) in the case of discolouration, but only 1.74 times (1.74:1) in the case of decay (Tab. S3, Tab. S4 in Supplementary material). The variation of transition probabilities as a function of stem diameter injury width is displayed in Fig. 4.
Fig. 4 - Transition probabilities of exceeding the sapwood boundary for (a) discoloration and (b) decay in beech stems as a function of injury width (x-axis) at different stem diameters (different coloured lines).
## Probability of formation and extent of red heartwood
Globally-significant logistic models of red heartwood formation confirmed the significance of two coefficients only, namely cambial age and injury width, while other investigated factors had no significant effect on red heartwood formation. The final equation describing the transition probability of red heartwood formation (p3) was defined as follows (eqn. 7):
$$p_3 = \frac{e ^ {(-7.99+ 0.06 x_1 + 0.39 x_2 )}} {1+ e ^ {(-7.99+ 0.06 x_1 + 0.39 x_2 )} }$$
where x1 is the cambial age of the stem and x2 is the unjury width.
With increased cambial age, the average odds of red heartwood formation increased by 1.06 times only (1.06:1); however, the increase in width of the injury raised the average odds by 1.47 times (1.47:1 - Tab. S5 in Supplementary material). The transition probability of red wood formation as a function of cambial age and injury width is displayed in Fig. 5.
Fig. 5 - Transition probability of red heartwood formation in beech stem as a function of injury width (x-axis) at different cambial ages (different coloured lines).
The results confirmed the assumption that a relatively strong correlation (r = 0.635, p = 0.002) exists between the size of the dehydrated zone and red heartwood. In most cases, the average value of red heartwood width was less than that of the estimated dehydrated zone. Only in three out of 20 cases the width of red heartwood was higher (Fig. S2 in Supplementary material). Also, cambial age had a relatively strong effect on red heartwood width (r = 0.645, p = 0.003 - Fig. S3 in Supplementary material). Therefore, the higher the cambial age of the stem, the greater the red heartwood width; however, injury width had a very weak effect (r = 0.163, p = 0.026 - Fig. S4).
# Discussion
All investigated injuries contained at least a minimal extent of discolouration, contrasting to the findings of Schumann & Dimitri ([31]), Hecht et al. ([12]) and Schulz ([30]), who reported that only 64%, 70% and 82% of 3-year-old open wounds contained discolouration in beech, respectively. Injuries with a lower average width and a shorter time period of injury closure did not contain decayed zones (Tab. 2). Decayed zones were present only in larger injuries with a longer time period of injury closure. According to Shortle et al. ([33]), decay in living trees occurs only in wood that has previously been discoloured. Also, it is generally known that larger and older wounds are more likely to be colonised by fungi ([39], [37]). In our case, 57% of injuries contained decay zones; however, Schumann & Dimitri ([31]) found only 25% of wounds due to logging which were infected by fungi. The extent of decay in radial direction was present in 49% of our cases, where they expanded by only 1 cm over three years. This means that beech is more resistant to wound-invading microorganisms, as compared with other species ([5]). However, discolouration at later stages of wood decay poorly inhibits the spread of decay. On the other hand, the reaction zone represents a strong and persistent static barrier against decay lesions ([24]). Therefore, the lower depth of decay compared to discolouration is probably due to a delay in the spread of wood decay (Fig. S1 in Supplementary material).
The injury width has a dominant impact on the extent of discolouration and decay of beech stems (Tab. 3), similarly to birch ([36]), whereas the impact is weak in ash ([38]). The injury closure period is also positively and linearly correlated with the extent of both discolouration and decay in beech (Tab. 3). The prolonged invasion of pathogens via open injuries enables the infection to penetrate deeper into the wooden tissues of the stem, whereas a weaker compartmentalisation allows an increase in the spreading rate of the discolouration and decay. Contrary to Vasaitis et al. ([36]), we found no significant difference in stem discolouration between open and occluded injuries in beech. Also, there was no significant correlation, as found in birch ([36]) or in ash ([38]). in this study, cambial age and stem diameter had the weakest correlation (Tab. 3), similar to the findings of Vasiliauskas & Stenlid ([38]) in ash.
Our results indicated that the extent of discolouration and decay depth in injuries was similar across different localities and stands. Small differences in some forest stands were influenced by a different cambial age, trunk diameter, injury width and injury closure period. Such differences could also be affected by the physiological state of individual trees ([8], [33]), the season of injury ([6], [7]), climatic conditions in the year of injury, different micro-organisms, pathogens, or saprophytes etc. Indeed, we observed a higher extent of discolouration and decay only in stands 744 A1 and 203 (1) from Bukovina (Tab. 4 and Tab. 5).
Biochemical processes and the moisture content of intact sapwood in beech represent a relatively strong defence barrier against the invasion of pathogens. On the other hand, the centripetal decreasing humidity and the sap flow density in beech stems ([11]) may facilitate the penetration of air and pathogens into the inner parts. Overall, the difference in the extent of discolouration and decay at different heights along the stem was only 0.1-0.4 m in depth (max 10 cm) over a three year-exposure ([6]), whereas it does not exceed 1.5-2 m during longer-term exposure ([8], [9]).
We found that not all injuries that exceeded the sapwood caused the formation of red heartwood. In the 32% of discoloured cases and 9% of decayed cases that exceed the sapwood, less than half of them (19%) led to red heartwood formation. In terms of typology, according to Sachsse ([27]), only 2.7% of red heartwood cases are categorised as abnormal heartwood (Fig. 3c). Further, all the monitored factors had no significant effect on the probability of exceeding the sapwood (Tab. S3 and Tab. S4 in Supplementary material) and forming red heartwood (Tab. S5).
Injured stems having a large diameter showed a lower probability that infection will exceed the sapwood, as pathogens have to travel a longer distance. Conversely, wider injuries have odds that are significantly higher (Fig. 4a and Fig. 4b). Cambial age and injury width also have a significant impact on the probability of red heartwood formation (Fig. 5, Tab. S5 in Supplementary material). Previous studies reported that tree age and diameter at breat height have a dominant effect on the frequency and size of red heartwood ([16], [17], [18], [40]). Krempl & Mark ([20]) also assumed that large wounds could be the initiation point of red heartwood formation. Sachsse & Simonsen ([28]) stated that the transformation from “wound heartwood” (discolouration of sapwood) to red heartwood may gradually occur in trees older than 75-90 years. Age-related alteration of vital parenchyma rays and moisture content in the dehydrated zone lead to an increased susceptibility to red heartwood formation in older trees. This is also supported by our findings that cambial age and dehydrated zone width are correlated with red heartwood width (Fig. S2 and Fig. S3 in Supplementary material), though the effect of injury width on red heartwood width was weak (Fig. S4). According to Fürst et al. ([10]), further studies should focus on the starting age/diameter of “dry heartwood” formation (analogous to dehydrated zone, or ripewood) in European beech to elucidate the above relationship. Indeed, the “dry heartwood” has the potential for later red heartwood formation, and thus can be used as an indicator for the risk of later wood quality loss.
# Conclusions
We conclude that only large stem injuries caused by bark stripping during thinning operations have the potential to initiate red heartwood formation in European beech. In particular, the width of sapwood and the dehydrated zone may affect such process. In this study, no significant difference in discoloration, decay and red heartwood formation were found across different sites and beech stands.
Although thinning can promote the growth of standing trees, intense interventions may cause frequent and large injuries on the stems, thus increasing the risk of infection that could cause an intensive red heartwood formation in aged beech trees. Therefore, the adoption of appropriate thinning strategies could reduce massive stem injuries and the probability of red heartwood formation in older target trees.
# Acknowledgements
We acknowledge the support from the Scientific Grant Agency of the Ministry of Education SR and the Slovak Academy of Sciences Grant No. 1/0822/17. This work was also supported by funding from the Slovak Research and Development Agency under the contracts no. APVV-16-0177 and no. APVV-0744-12.
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Schatz U, Heräjärvi H, Kannisto K, Rantatalo M (2008). Influence of saw and secateur pruning on stem discolouration, wound cicatrisation and diameter growth of Betula pendula. Silva Fennica 42: 295-305.
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Schulz H (1973). Auswirkungen von Rückeschäden an jungen Buchen und Edellaubhölzern [Effect of logging wounds in young beech and other hardwoods]. Holzforschung 27: 43-47. [in German]
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Schumann G, Dimitri L (1993). Wunden und wundfäulen bei der Buche. [Wounds and wound rot in beech]. Allgemeine Forstzeitschrift 48: 456-460. [in German]
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Shigo AL, Hillis WE (1973). Heartwood, discolored wood, and microorganisms in living trees. Annual Review of Phytopathology 11: 197-222.
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Shortle WC, Smith KT, Dudzik KR (1996). Decay diseases of stemwood: detection, diagnosis, and management. In: “Forest trees and palms” (Raychaudhuri SP, Maramorosch K eds). Oxford and IBH Publishing, New Delhi, India, pp. 95-109.
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Torelli N (1984). The ecology of discolored wood as illustrated by beech (Fagus sylvatica L.). IAWA Bulletin 5: 121-127.
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Vartiamäki H, Hantula J, Uotila A (2009). Susceptibility of silver birch pruning wounds to infection by white-rot fungus (Chondrostereum purpureum), a potential bioherbicide. Silva Fennica 43: 537-547.
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Vasiliauskas R (2001). Damage to trees due to forestry operations and its pathological significance in temperate forests: a literature review. Forestry 74: 319-336.
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Vasiliauskas R, Stenlid J (1998a). Discoloration following bark stripping wounds on Fraxinus excelsior. European Journal of Forest Pathology 28: 383-390.
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Vasiliauskas R, Stenlid J (1998b). Fungi inhabiting stems of Picea abies in a managed stand in Lithuania. Forest Ecology and Management 109: 119-126.
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#### Authors’ Affiliation
(1)
Olga Mišíková
Department of Wood Science, Technical University in Zvolen, T.G.Masaryka 24, 960 53 Zvolen (Slovakia)
(2)
Pavol Hlaváč
Department of Integrated Forest Protection and Landscape, Technical University in Zvolen, T.G.Masaryka 24, 960 53 Zvolen (Slovakia)
(3)
Veronika Deáková
Institute of Foreign Languages, Technical University in Zvolen, T.G.Masaryka 24, 960 53 Zvolen (Slovakia)
racko@tuzvo.sk
#### Citation
Račko V, Mišíková O, Hlaváč P, Deáková V (2018). Can bark stripping cause red heartwood formation in beech stems?. iForest 11: 251-258. - doi: 10.3832/ifor2147-011
Giacomo Goli
#### Paper history
Accepted: Dec 27, 2017
First online: Mar 12, 2018
Publication Date: Apr 30, 2018
Publication Time: 2.50 months
© SISEF - The Italian Society of Silviculture and Forest Ecology 2018
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https://cantera.org/examples/jupyter/electrochemistry/lithium_ion_battery.ipynb.html | Lithium Ion Battery Example¶
Note: the example below requires Cantera 2.5.0a2 or newer¶
If the stable release of 2.5.0 is not yet available, you might consider building from source. Note also that 2.5.0, once released, is more recent than and supercedes 2.5.0a2, which is an alpha release.
Open circuit calculations as a function of anode and cathode lithium content.¶
In this example we will illustrate how to calculate the open circuit voltage (voltage when the external applied current is 0) for a lithium ion battery. The thermodynamics are based on a graphite anode and a LiCoO2 cathode (the typical/standard active materials for commercial batteries, as of 2019), and are modeled using the 'BinarySolutionTabulatedThermo' class.
For the sake of simplicity, we're going to assume that the anode and cathode capacities are perfectly balanced (i.e. if the cathode lithium content is X percent of its max possible (i.e. its capacity), then we will assume that the anode is at 1-X percent. Without loss of generality, we will define the anode composition.
The routine below returns the cell voltage (in Volt) of a lithium-ion cell for a given cell current and active material lithium stoichiometries.
Note that the function 'E_cell' below has even greater capabilities than what we use, here. It calculates the steady state cell voltage, at a given composition and cell current, for a given electrolyte ionic resistance. This functionality is presented in greater detail in the reference (which also describes the derivation of the BinarySolutionTabulatedThermo class): M. Mayur, S. DeCaluwe, B. L. Kee, W. G. Bessler, "Modeling thermodynamics and kinetics of intercalation phases for lithium-ion batteries in open source software", currently under review at Electrochimica Acta. In the future, this example may be developed further to demonstrate simulating charge-discharge of the lithium ion battery.
Other than the typical Cantera dependencies, plotting functions require that you have matplotlib installed, and finding the electrode potentials uses Scipy's fsolve. See https://matplotlib.org/ and https://docs.scipy.org/doc/scipy/reference/generated/scipy.optimize.fsolve.html for additional info.
The open circuit (i.e. equilibrium) voltage, here, is calculated via two means: kinetically and thermodynamically.
The system here, can be thought of as consisting of two particles--anode and cathode--connected by a liquid electrolyte:
Kinetic equilibrium calculations¶
In the kinetic equilibrium problem, steady state is achieved when the faradaic current at each electrode (anode and cathode) surface and the ionic current through the electrolyte are all zero. There are, essentially, four relevant electric potentials which must be determined:
• $\phi_{\rm anode}$: electric potential of graphite anode.
• $\phi_{\rm elyte,\, anode}$: electric potential of electrolyte at anode interface.
• $\phi_{\rm elyte,\, cathode}$: electric potential of electrolyte at cathode interface.
• $\phi_{\rm cathode}$: electric potential of LCO cathode.
Setting one of these four to the reference potential of zero (because it is the difference in electric potential which drives currents, the actual potential values are irrelevant. Let's assume the anode electric potential is zero), there is only one distribution of electric potentials across the cell such that the current is invariant across the cell. I.e. we want the potentials such that:
$$i_{\rm Far,\, anode} = i_{\rm ionic} = i_{\rm Far,\,cathode}= i_{\rm app}$$
where $i_{\rm app}$ is the user input for the applied current. For this example, we assume an applied current of 0, to calculate the equilibrium voltage.
The Faradaic current for this model is calculated using Butler-Volmer kinetics. For a Li-ion battery, this is:
$$i = S_{\rm elde}i_\circ\left[\exp\left(\frac{F\beta\eta}{RT}\right) - \exp\left(-\frac{F(1-\beta)\eta}{RT}\right) \right]$$
where $S_{\rm elde}$ is the specific surface area of the electrode in question, $F$ is Faraday's constant, $\beta$ is the charge-transfer symmetry parameter, $R$ the universal gas constant, $T$ the temperature, and $\eta$ the overpotential, which is the electric potential difference between the electrode and electrolyte, $\Delta \phi = \phi_{\rm elde} - \phi_{\rm elyte}$, relative to that at equilibrium, $\Delta \phi_{\rm eq}$:
$$\eta = \Delta \phi - \Delta \phi_{\rm eq}$$
$i_\circ$ is known as the "exchange current density," which is equal to the rate of the forward and reverse current at equilibrium (which are equal). $i_\circ$ and $\beta$ are provided as user inputs in the cti file. At any particular state, (user-specified electric potentials, pressure, temperature, and chemical compositions), Cantera calculates $\eta$ as part of the routine to evaluate reaction rates of progress $\left(\dot{q} = \frac{i_{\rm Far}}{F}\right)$. The user simply sets the state values mentioned above.
Ionic current¶
The electrolyte is modeled as a resistor with user-defined ionic resistance $R_{\rm io}$, and hence the ionic current is calculated as:
$$i_{\rm ionic} = \frac{\phi_{\rm elyte,\,ca} - \phi_{\rm elyte,\,an}}{R_{\rm io}}$$
where positive current is defined as delivering Li$^+$ to the anode interface. Given $i_{\rm app}$, this equation can be inverted, to calculate the electric potential of the electrolyte at the cathode interface, relative to that at the anode interface:
$$\phi_{\rm elyte,\,ca} = \phi_{\rm elyte,\,an} + R_{\rm io}i_{\rm app}$$
Again: in this example, $i_{\rm app} = 0$ and hence the two electric potential values in the electrolyte are equal.
Numerical routine¶
For the kinetic routine, there are three processes to determine the cell voltage $\phi_{\rm cathode} - \phi_{\rm anode}$ which corresponds to the user-provided $i_{\rm app}$:
1. Determine the $\phi_{\rm elyte,\,anode}$ value which corresponds to $i_{\rm app}$, given $X_{\rm Li, anode}$, the percentage of Li in the anode active material.
2. Determine $\phi_{\rm elyte,\,cathode}$, given $\phi_{\rm elyte,\,anode}$ and $i_{\rm app}$.
3. Determine the $\phi_{\rm cathode}$ which corresponds to $i_{\rm app}$, given $\phi_{\rm elyte,\,cathode}$ and $X_{\rm Li, anode}$, the percentage of Li in the anode active material.
The routines below are written generally such that an interested user may set $i_{\rm app}$ to any value of interest.
Import necessary packages:¶
In [1]:
import cantera as ct
print('Runnning Cantera version: ' + ct.__version__)
Runnning Cantera version: 2.5.0a2
In [2]:
import numpy as np
from scipy.optimize import fsolve
# Used for timing our calculations:
import time
# Plotting:
%matplotlib notebook
import matplotlib.pyplot as plt
plt.rcParams['axes.labelsize'] = 16
plt.rcParams['xtick.labelsize'] = 12
plt.rcParams['ytick.labelsize'] = 12
plt.rcParams['figure.autolayout'] = True
Define the phases¶
The phase thermodynamics are defined according to experimentally-measured open circuit voltage values, as desscribed in the reference provided above:
In [3]:
inputCTI = 'data/lithium_ion_battery.cti'
anode = ct.Solution(inputCTI, 'anode');
cathode = ct.Solution(inputCTI, 'cathode');
# The 'elde' electrode phase is needed as a source/sink for electrons:
elde = ct.Solution(inputCTI, 'electron');
elyte = ct.Solution(inputCTI, 'electrolyte');
anode_interface = ct.Interface(inputCTI, 'edge_anode_electrolyte', [anode, elde, elyte]);
cathode_interface = ct.Interface(inputCTI, 'edge_cathode_electrolyte', [cathode, elde, elyte]);
Define battery conditions : temperature, pressure, stoichiometry, electrolyte resistance:¶
Inputs are:
• Stoichiometries X_Li_ca and X_Li_an [-] (can be vectors)
• Temperature T [K]
• Pressure P [Pa]
• Externally-applied current i_app [A]
• Electrolyte resistance R_elyte [Ohm]
• Anode total surface area S_an [m^2]
• Cathode total surface area S_ca [m^2]
In [4]:
# Array of lithium mole fractions in the anode:
X_Li_an = np.arange(0.005, 0.995, 0.02)
# Assume that the cathode and anode capacities are balanced:
X_Li_ca = 1. - X_Li_an;
# I_app = 0: Open circuit
I_app = 0.;
# At zero current, electrolyte resistance is irrelevant:
R_elyte = 0.;
# Temperature and pressure
T = 300 # K
P = ct.one_atm
S_ca = 1.1167; # [m^2] Cathode total active material surface area
S_an = 0.7824; # [m^2] Anode total active material surface area
Set phase temperatures and pressures:¶
In [5]:
phases = [anode, elde, elyte, cathode, anode_interface, cathode_interface];
for ph in phases:
ph.TP = T, P
Helper Functions:¶
In [6]:
def anode_curr(phi_l,I_app,phi_s,X_Li_an):
# Set the active material mole fraction
anode.X = 'Li[anode]:' + str(X_Li_an) + ', V[anode]:' + str(1 - X_Li_an)
# Set the electrode and electrolyte potential
elde.electric_potential = phi_s
elyte.electric_potential = phi_l
# Get the net product rate of electrons in the anode (per m2^ interface)
r_elec = anode_interface.get_net_production_rates(elde)
diff = I_app + anCurr
return diff
def cathode_curr(phi_s,I_app,phi_l,X_Li_ca):
# Set the active material mole fractions
cathode.X = 'Li[cathode]:' + str(X_Li_ca) + ', V[cathode]:' + str(1 - X_Li_ca)
# Set the electrode and electrolyte potential
elde.electric_potential = phi_s
elyte.electric_potential = phi_l
# Get the net product rate of electrons in the cathode (per m2^ interface)
r_elec = cathode_interface.get_net_production_rates(elde)
diff = I_app - caCurr
return diff
Run the calculations for all stoichiometries:¶
In [7]:
# Tic
t0 = time.time()
# Initialize array of OCVs:
E_cell_kin = np.zeros_like(X_Li_ca)
for i,X_an in enumerate(X_Li_an):
#Set anode electrode potential to 0:
phi_s_an = 0
E_init = 3.0
phi_l_an = fsolve(anode_curr,E_init,args=(I_app, phi_s_an, X_an))
# Calculate electrolyte potential at cathode interface:
phi_l_ca = phi_l_an + I_app*R_elyte;
# Calculate cathode electrode potential
phi_s_ca = fsolve(cathode_curr,E_init,args=(I_app, phi_l_ca, X_Li_ca[i]))
# Calculate cell voltage
E_cell_kin[i] = phi_s_ca - phi_s_an
# Toc
t1 = time.time()
print('{:d} cell voltages calculated in {:3.2f} seconds.'.format(i, t1 - t0))
49 cell voltages calculated in 0.61 seconds.
Plot cell voltage, as a function of the cathode stoichiometry:¶
In [8]:
plt.figure()
plt.plot(100*X_Li_ca, E_cell_kin, color='b', linewidth=2.5)
plt.ylim([2.5, 4.3])
plt.xlabel('Li Fraction in Cathode (%)', fontname='Times New Roman', fontsize=18)
plt.ylabel('Open Circuit Potential (V)', fontname='Times New Roman', fontsize=18)
ax = plt.gca()
for tick in ax.xaxis.get_major_ticks():
tick.label1.set_fontsize(14)
tick.label1.set_fontname('Times New Roman')
for tick in ax.yaxis.get_major_ticks():
tick.label1.set_fontsize(14)
tick.label1.set_fontname('Times New Roman')
Thermodynamic Equilibrium Calculation¶
For the $i_{app} = 0$ case, we can also calcualte the voltage using thermodynamics. At equilibrium, the net electrochemical potential change of the reaction must be zero:
$$\sum_k\nu_k\tilde{\mu}_k = 0$$
where $\tilde{\mu}_k = \mu_k + z_kF\Phi_k$, where, in turn $\mu_k = \frac{\partial g_k}{\partial n_k}$ is the chemical potential, $\nu_k$ the net stoichiometric coefficient, $z_k$ the net elementary charge, and $\Phi_k$ the phase electric potential for species $k$.
From this, we can calculate the equilibrium electric potential difference $\Delta \Phi_{\rm eq} = \left(\Phi_{\rm elde} - \Phi_{\rm elyte}\right)_{\rm eq}$ as:
$$\Delta \Phi_{\rm eq} = -\frac{\Delta g_{\rm rxn}}{n_{\rm charge}F}$$
where $\Delta g_{\rm rxn} = \sum_k \nu_k\mu_k$ is the chemical potential of the reaction and and $n_{\rm charge} = \sum_{k,\,{\rm elde}} \nu_k z_k$ is the net elementary charge transferred from the electrolyte to the electrode.
In [9]:
# Tic
t0 = time.time()
# Initialize array of OCVs:
E_cell_therm = np.zeros_like(X_Li_ca)
for i, X_an in enumerate(X_Li_an):
#Set anode electrode potential to 0:
anode.X = 'Li[anode]:' + str(X_an) + ', V[anode]:' + str(1 - X_an)
dG_an = anode_interface.delta_gibbs[0]
n_charge = -1.
cathode.X = 'Li[cathode]:' + str(1. - X_an) + ', V[cathode]:' + str(X_an)
dG_ca = cathode_interface.delta_gibbs[0]
n_charge = 1.
E_cell_therm[i] = E_eq_ca - E_eq_an
# Toc
t1 = time.time()
print('{:d} cell voltages calculated in {:3.2f} seconds.'.format(i, t1 - t0))
49 cell voltages calculated in 0.03 seconds.
Plot thermodynamic OCV, and compare to results from kinetic method¶
In [10]:
plt.figure()
plt.plot(100*X_Li_ca, E_cell_therm,color='b', linewidth=2.5)
plt.plot(100*X_Li_ca, E_cell_kin,linewidth=0., marker='o', markerfacecolor='none', markeredgecolor='r')
plt.ylim([2.5, 4.3])
plt.xlabel('Li Fraction in Cathode (%)', fontname='Times New Roman', fontsize=18)
plt.ylabel('Open Circuit Potential (V)', fontname='Times New Roman', fontsize=18)
plt.legend(['Thermodynamic', 'Kinetic'])
ax = plt.gca()
for tick in ax.xaxis.get_major_ticks():
tick.label1.set_fontsize(14)
tick.label1.set_fontname('Times New Roman')
for tick in ax.yaxis.get_major_ticks():
tick.label1.set_fontsize(14)
tick.label1.set_fontname('Times New Roman')
As one would expect, the two approaches give identical results. While both methods are incredibly fast, the thermodynamic method is roughly 30 times faster.
A large part of this is that the thermodynamic approach is an analytical approach (i.e. the answer is known from theory), while the kinetic approach relies on the root-finding fzero method to fit the correct voltage. Note also that the kinetic method, because of the use of Butler-Volmer kinetics, calculates the thermodynamic voltage, in order to calculate the overpotential $\eta = \Delta \Phi - \Delta \Phi_{\rm eq}$.
However, it is at last important to note that, while slower, the kinetic method is of course more robust, and can be used to find results away from equilibrium. The thermodynamic method is only applicable at equilibrium (zero current). | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 8, "x-ck12": 0, "texerror": 0, "math_score": 0.8107541799545288, "perplexity": 4907.954021502099}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-18/segments/1555578517682.16/warc/CC-MAIN-20190418141430-20190418163430-00178.warc.gz"} |
http://docs.itascacg.com/3dec700/3dec/block/doc/manual/flow_manual/flow_fish/flowplane.vertex/fish_flowplane.vertex.proppant.mconc.html | # flowplane.vertex.proppant.mconc
Syntax
f = flowplane.vertex.proppant.mconc(fpvp)
Get the mass concentration of proppant of a flow plane vertex.
Returns: f - mass concentration fpvp - flow plane vertex pointer | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.42266416549682617, "perplexity": 24747.76206613879}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-39/segments/1631780058222.43/warc/CC-MAIN-20210926235727-20210927025727-00481.warc.gz"} |
http://www.chemgapedia.de/vsengine/vlu/vsc/en/ch/12/oc/vlu_organik/substitution/sn_1/sn_1.vlu/Page/vsc/en/ch/12/oc/substitution/sn_1/loesungsmittel/loesungsmittel.vscml.html | # SN1 - First-order Nucleophilic Substitution
## Influence of the Solvent on $SN1$ Reactions
The solvent plays a great role in $SN1$ reactions. However, in contrast to $SN2$ reactions, it is not the stabilization of the nucleophile, but the stabilization of the first reaction step's transition state and the stability of the intermediate that influence the reaction rate, as the nucleophile does not participate in the rate-determining step. Due to its ionic structure or polar character, the intermediate and transition state can be effectively stabilized by polar and protic solvents. As a result of the transition state's stabilization by a polar (or protic) solvent, the activation energy is decreased, as the non-ionic and comparatively less polar starting product is stabilized by the solvent to a lesser degree.
### Animation
Fig.1
Fig.2
Stabilization of a tertiary alkyl bromide's transition state by the solvent water in an $SN1$ reaction.
Fig.3
Stabilization of the intermediate carbocation and bromide anion by the solvent water in an $SN1$ reaction.
The ability of solvents to stabilize ions through solvation is directly associated with their polarity. Polar solvents, such as water, methanol, and dimethyl sulphoxide, can effectively stabilize ions through solvation, while non-polar solvents, such as ether and hydrocarbons, cannot. The dielectric constant is a measure of a solvent's polarity. The higher the dielectric constant of a solvent is, the higher its polarity also is and, thus, cations and anions may be separated by the solvent molecules more efficiently.
Protic (organic) solvents possess acidic hydrogens. These are usually bound to oxygen or nitrogen. In hydrogen bridge bonds, the acidic hydrogen acts as an acceptor of electron density, while the heteroatom (usually oxygen or nitrogen) acts as a donator, as the hydrogen-heteroatom bond is polarized due to the electronegativity difference of the atoms in question. Thus, this type of solvent is able to stabilize not only positively charged, but also negatively charged, ions and molecules.
Tab.1
Dielectric constants (ε, at 25°C) of some common solvents.
Aprotic solventsεProtic solventsε
Hexane 1.9 Acetic acid 6.2
Benzene 2.3 1-Methyl-2-propanol 11
Diethyl ether 4.3 Ethanol 34.3
Chloroform 4.8 Methanol 33.6
Hexamethylphosphoramide (HMPT) 30 Formic acid 58.0
Dimethyl formamide (DMF) 38 Water 80.4
Dimethyl sulfoxide (DMSO) 48
Due to the points made above, $SN1$ reactions proceed much more rapidly in polar than in non-polar solvents. The nucleophilic substitution of 2-chloro-2-methylpropane in water, for instance, runs 100,000 times faster than that in ethanol.
Fig.4
Influence of the solvent on $SN1$ reactions of 2-chloro-2-methylpropane.
$SN1$ reactions proceed more rapidly in protic, polar solvents because such solvent molecules stabilize the (rate-determining) transition state and the intermediate carbocation. That is, the transition state is lower in energy than in aprotic, non-polar solvents, while the energy of the starting product is hardly influenced by the solvent. As a result, the activation energy in protic, polar solvents is lower than that in aprotic, non-polar solvents.
Page 8 of 10 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 8, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8779516220092773, "perplexity": 4435.267353839413}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-22/segments/1495463608633.44/warc/CC-MAIN-20170526032426-20170526052426-00314.warc.gz"} |
https://ijnaa.semnan.ac.ir/article_6397.html | ### New sandwich results for univalent functions defined by the Tang-Aouf operator
Document Type : Research Paper
Authors
Department of Mathematics, College of Science, University of Al-Qadisiyah, Diwaniyah, Iraq
Abstract
In this paper, we study some differential subordination and subordination results for certain subclass of univalent functions in the open unit disc U using generalized operator $H^{\lambda,\delta}_{\eta,\mu}$. Also, we derive some sandwich theorems.
Keywords | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.803482711315155, "perplexity": 1809.7183030010176}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764500250.51/warc/CC-MAIN-20230205063441-20230205093441-00734.warc.gz"} |
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# Gearbox casing heat rejection2
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## Gearbox casing heat rejection
(OP)
Hi,
I'm looking for an approximate value for the heat rejection to ambient air of a typical transmission casing.
Watts/surface-area for an aluminium casting in free air would be a good starting point.
I need to calculate the size of the oil cooler, but want to subtract the heat rejection of the casing first.
Many thanks, Ian
### RE: Gearbox casing heat rejection
2
Ian,
The heat in a gearbox is generated thru several mechanisms. If your gears have high pitch line velocities, then oil windage losses can predominate. Oil churning losses in bearings can also be significant if scavenging and drainage flows are not paid attention to. And if your gear meshes have lots of sliding, they will require high flows.
If your gears are supported in rolling element bearings, then they are fairly well thermally isolated from the housing structure, and most of the heat transfer out of the gear teeth/rims must be accomplished thru oil jetting. The difficulty with doing this is that the oil spends very little time actually in contact with the gear teeth, so it experiences only a modest temperature rise before it is flung off. With a small temperature rise, you must naturally increase mass flow rates to effect your desired heat transfer rate.
My experience is mostly designing aircraft transmissions with aluminum cases. The total mechanical (gears, bearings, splines, seals, etc.) and windage losses of these systems is usually about 4%. As a rule of thumb, I would recommend starting with a bulk oil flow temperature rise of about 40degF, from jet to sump, to be conservative. We typically design for oil inlet temps of 230degF max under normal conditions with mil-spec gear oil, so bulk oil out would be 270degF max. The oil system volume is also normally kept very small to minimize weight, so the oil turnover rate thru the system is naturally very high. Usually around 4X per minute.
Having said all that, the heat transfer variables across the wall of an aluminum casing is something you'll have to make some assumptions about until you get your hands on some test data. You can easily determine the thermal conductivity of the aluminum, you can analyse for the total exterior surface area, you can safely assume that the inner surface of the casing is at (or near) bulk oil temp, but you'll likely have to guess at the local ambient air mass flows and temperature. Once again, as a conservative rule of thumb to start with, I would recommend assuming about 10% of the heat load being rejected thru the case wall structure with an aluminum housing in static air.
The other 90% of the heat load must be rejected thru your cooler. Unfortunately, the cooler core always ends up being a lot larger than you would expect, since you must size it for conditions of max power, on a hot day, at high altitude.
Good luck,
Terry
### RE: Gearbox casing heat rejection
Hmm, informative post but orthogonal to the thread I think.
According to my thermo book the heat transfer coefficient in air is
.0005 to 1 kW m-2 K-1
That's right the estimate varies by a factor of 2000!
My Heat transfer book is even less helpful.
Here's what Ye Olde gearbox booke (practically a scroll) says
H=C*A*dT
H in ft lb/min (that'd be hp/33000)
dT in fahrenheit
A in sq in
C is 0.45 for A=0, .33 for A=10000 and .27 for A=20000
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
### RE: Gearbox casing heat rejection
I think the wide variance in transfer coefficient is probalby due to clean vs. oxidized surface. My data for room temperature is 840-1540 BTU/hr./sq.ft./°F.
ISZ
### RE: Gearbox casing heat rejection
FWIW - My old "Machine Design" by Deutschman, Michels, and Wilson says a widely used heat transfer coefficient (C) for bearing heat balance calcs is approximated as 2 BTU/(hr)(ft2)( degree F) for still air. If air velocity is 500 ft/min, then 5.9 BTU....... is suggested.
### RE: Gearbox casing heat rejection
Sorry if you thought my post was a bit long winded, but the original question posed was more than simply asking for a heat transfer coefficient for aluminum in still air. Any decent text will give you that.
I just spent a very long time doing exactly this analysis for a large aircraft transmission. Sizing the oil heat exchanger core was no straightforward task. It ultimately involves lots of educated assumptions. And I'm sure the heat exchanger core size will change after both bench testing and flight testing.
What Ian stated is that his real task is to size an oil cooler for his transmission. And he wished to start by subtracting the heat rejected thru the aluminum case from the total heat load that must be rejected thru the cooler core. All other things being equal, heat transfer thru the case wall is most affected by the deltaT. To accurately establish the deltaT across the case wall, you must firstly understand how the oil-to-inner-case-wall heat transfer mechanism works, and what factors drive it.
Some of the oil, like that used to cool bearings, will not have much temperature rise and will likely drain directly into the sump without contacting the case wall. Other oil flows, like those used to cool gear meshes, will experience much greater temperature rise, and will be flung and wetted-out against almost all inner surfaces of the case. Thus the oil flow heating the case will be at a higher local temperature than the bulk oil flow temps measured in the sump.
To make a long story short, accurately sizing a transmission heat exchanger (by analysis) is no simple matter. And that was the real point I feebly attempted to make with my long-winded post.
Best regards,
Terry
### RE: Gearbox casing heat rejection
Yes, and it was a very useful post. In fact have a star. That and 3 dollars will get you a cup of coffee.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
### RE: Gearbox casing heat rejection
Three bucks for a cup of coffee? That works out to over $30/gal. And to think people complain about paying$3/gal for gasoline!
In case you're interested regarding the topic of how complicated some gearbox lube system analyses can get, the one I'm currently working on has over 160 separate oil jet orifices in the system. Thank God for Excel!
Best regards,
Terry
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Register now while it's still free! | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2162957638502121, "perplexity": 3638.892338347965}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-14/segments/1427131298755.8/warc/CC-MAIN-20150323172138-00057-ip-10-168-14-71.ec2.internal.warc.gz"} |
http://mathhelpforum.com/statistics/112757-neurotic-dogs.html | 1. ## neurotic dogs
Problem:
I have two dogs and they're very neurotic. Mingus isn't happy unless at least 2 of his 3 favorite chewtoys are in the backyard with him, and Duke isn't happy unless at least 3 of his 5 favorite chewtoys are in the frontyard with him.
The probability that any particular chewtoy is not in its respective dog's yard is 1-a. (Note that the probability is independent from chewtoy to chewtoy, but the probabilities themselves are all the same). For what values of a is Mingus' happiness more probable than Duke's happiness?
What I think:
Intuitively, I want to say that since the probabilities are all the same that it's always a safer bet on Mingus' happiness over Duke's, but I've learned that my intuition sucks at probability. So I tried calculating the probability that each dog will be happy. I'll use my Mingus calculation as an example:
Prob(Mingus happy) =
=1-Prob(Mingus not happy)
= 1-Prob(2 Mingus toys missing or 3 Mingus toys missing)
= 1-( a(1-a)^2 + (1-a)^3 ) = 2a-a^2 (if I did my algebra right)
I also tried:
Prob(Mingus happy)=
=Prob(2 Mingus toys in yard or 3 Mingus toys in yard)
=a^2 * (1-a) + a^3 = a^2.
So I have two issues, and any clarification on these would be awesome:
(1) I got something different when I tried to calculate the same thing two different ways, and
(2) by either way of doing, I set Prob(Mingus happy) > Prob(Duke happy) and tried to solve for a range of values for a but got either something unhelpful or an inequality that agreed with my earlier intuition.
2. Hello cribby
Welcome to Math Help Forum!
Originally Posted by cribby
Problem:
I have two dogs and they're very neurotic. Mingus isn't happy unless at least 2 of his 3 favorite chewtoys are in the backyard with him, and Duke isn't happy unless at least 3 of his 5 favorite chewtoys are in the frontyard with him.
The probability that any particular chewtoy is not in its respective dog's yard is 1-a. (Note that the probability is independent from chewtoy to chewtoy, but the probabilities themselves are all the same). For what values of a is Mingus' happiness more probable than Duke's happiness?
What I think:
Intuitively, I want to say that since the probabilities are all the same that it's always a safer bet on Mingus' happiness over Duke's, but I've learned that my intuition sucks at probability. So I tried calculating the probability that each dog will be happy. I'll use my Mingus calculation as an example:
Prob(Mingus happy) =
=1-Prob(Mingus not happy)
= 1-Prob(2 Mingus toys missing or 3 Mingus toys missing)
= 1-( a(1-a)^2 + (1-a)^3 ) = 2a-a^2 (if I did my algebra right)
I also tried:
Prob(Mingus happy)=
=Prob(2 Mingus toys in yard or 3 Mingus toys in yard)
=a^2 * (1-a) + a^3 = a^2.
So I have two issues, and any clarification on these would be awesome:
(1) I got something different when I tried to calculate the same thing two different ways, and
(2) by either way of doing, I set Prob(Mingus happy) > Prob(Duke happy) and tried to solve for a range of values for a but got either something unhelpful or an inequality that agreed with my earlier intuition.
Thanks for showing us your working. You're going wrong in the same way in both of your methods.
The probability that any given toy is in the yard is $a$. So the probability that $2$ out of $3$ toys are in the yard is $3 a^2(1-a)$. You forgot to multiply by $3$. The reason the $3$ is there is because there are $3$ ways in which this event can happen, depending upon exactly which of the $3$ toys is not in the yard. So the probability that Mingus is happy is
$p(2$ out of $3) + p(3$ out of $3) = 3a^2(1-a)+a^3 = 3a^2 -2a^3$
In general if we want the probability that $r$ out of $n$ toys are in the yard we use the Binomial Coefficient $\binom{n}{r}$, and get the probability
$\binom{n}{r}a^r(1-a)^{n-r}$
So, for example, the probability that 3 out of Duke's 5 toys are in the yard is
$\binom53a^3(1-a)^2=10a^3(1-2a+a^2)$
So work out the probability that $3, 4$ or $5$ of Duke's toys are in the yard; add these together and set the result to be less than the result for Mingus that I've given you above.
When I do this and simplify the result I get the inequality
$2a^3-5a^2+4a-1 <0$.
This gives the answer $0.
Do you want to try again and see if you agree with my answer? | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 20, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7670043706893921, "perplexity": 1482.0739541539165}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-34/segments/1502886109157.57/warc/CC-MAIN-20170821152953-20170821172953-00599.warc.gz"} |
https://www.tensorflow.org/versions/r0.11/api_docs/python/framework/core_graph_data_structures | # Core graph data structures
### class tf.Graph
A TensorFlow computation, represented as a dataflow graph.
A Graph contains a set of Operation objects, which represent units of computation; and Tensor objects, which represent the units of data that flow between operations.
A default Graph is always registered, and accessible by calling tf.get_default_graph(). To add an operation to the default graph, simply call one of the functions that defines a new Operation:
c = tf.constant(4.0)
assert c.graph is tf.get_default_graph()
Another typical usage involves the Graph.as_default() context manager, which overrides the current default graph for the lifetime of the context:
g = tf.Graph()
with g.as_default():
# Define operations and tensors in g.
c = tf.constant(30.0)
assert c.graph is g
Important note: This class is not thread-safe for graph construction. All operations should be created from a single thread, or external synchronization must be provided. Unless otherwise specified, all methods are not thread-safe.
#### tf.Graph.__init__() {:#Graph.init}
Creates a new, empty Graph.
#### tf.Graph.as_default()
Returns a context manager that makes this Graph the default graph.
This method should be used if you want to create multiple graphs in the same process. For convenience, a global default graph is provided, and all ops will be added to this graph if you do not create a new graph explicitly. Use this method with the with keyword to specify that ops created within the scope of a block should be added to this graph.
The default graph is a property of the current thread. If you create a new thread, and wish to use the default graph in that thread, you must explicitly add a with g.as_default(): in that thread's function.
The following code examples are equivalent:
# 1. Using Graph.as_default():
g = tf.Graph()
with g.as_default():
c = tf.constant(5.0)
assert c.graph is g
# 2. Constructing and making default:
with tf.Graph().as_default() as g:
c = tf.constant(5.0)
assert c.graph is g
##### Returns:
A context manager for using this graph as the default graph.
#### tf.Graph.as_graph_def(from_version=None, add_shapes=False)
Returns a serialized GraphDef representation of this graph.
The serialized GraphDef can be imported into another Graph (using import_graph_def()) or used with the C++ Session API.
This method is thread-safe.
##### Args:
• from_version: Optional. If this is set, returns a GraphDef containing only the nodes that were added to this graph since its version property had the given value.
• add_shapes: If true, adds an "_output_shapes" list attr to each node with the inferred shapes of each of its outputs.
##### Returns:
A GraphDef protocol buffer.
##### Raises:
• ValueError: If the graph_def would be too large.
#### tf.Graph.finalize()
Finalizes this graph, making it read-only.
After calling g.finalize(), no new operations can be added to g. This method is used to ensure that no operations are added to a graph when it is shared between multiple threads, for example when using a QueueRunner.
#### tf.Graph.finalized
True if this graph has been finalized.
#### tf.Graph.control_dependencies(control_inputs)
Returns a context manager that specifies control dependencies.
Use with the with keyword to specify that all operations constructed within the context should have control dependencies on control_inputs. For example:
with g.control_dependencies([a, b, c]):
# d and e will only run after a, b, and c have executed.
d = ...
e = ...
Multiple calls to control_dependencies() can be nested, and in that case a new Operation will have control dependencies on the union of control_inputs from all active contexts.
with g.control_dependencies([a, b]):
# Ops constructed here run after a and b.
with g.control_dependencies([c, d]):
# Ops constructed here run after a, b, c, and d.
You can pass None to clear the control dependencies:
with g.control_dependencies([a, b]):
# Ops constructed here run after a and b.
with g.control_dependencies(None):
# Ops constructed here run normally, not waiting for either a or b.
with g.control_dependencies([c, d]):
# Ops constructed here run after c and d, also not waiting
# for either a or b.
N.B. The control dependencies context applies only to ops that are constructed within the context. Merely using an op or tensor in the context does not add a control dependency. The following example illustrates this point:
# WRONG
def my_func(pred, tensor):
t = tf.matmul(tensor, tensor)
with tf.control_dependencies([pred]):
# The matmul op is created outside the context, so no control
# dependency will be added.
return t
# RIGHT
def my_func(pred, tensor):
with tf.control_dependencies([pred]):
# The matmul op is created in the context, so a control dependency
# will be added.
return tf.matmul(tensor, tensor)
##### Args:
• control_inputs: A list of Operation or Tensor objects which must be executed or computed before running the operations defined in the context. Can also be None to clear the control dependencies.
##### Returns:
A context manager that specifies control dependencies for all operations constructed within the context.
##### Raises:
• TypeError: If control_inputs is not a list of Operation or Tensor objects.
#### tf.Graph.device(device_name_or_function)
Returns a context manager that specifies the default device to use.
The device_name_or_function argument may either be a device name string, a device function, or None:
• If it is a device name string, all operations constructed in this context will be assigned to the device with that name, unless overridden by a nested device() context.
• If it is a function, it will be treated as a function from Operation objects to device name strings, and invoked each time a new Operation is created. The Operation will be assigned to the device with the returned name.
• If it is None, all device() invocations from the enclosing context will be ignored.
For information about the valid syntax of device name strings, see the documentation in DeviceNameUtils.
For example:
with g.device('/gpu:0'):
# All operations constructed in this context will be placed
# on GPU 0.
with g.device(None):
# All operations constructed in this context will have no
# assigned device.
# Defines a function from Operation to device string.
def matmul_on_gpu(n):
if n.type == "MatMul":
return "/gpu:0"
else:
return "/cpu:0"
with g.device(matmul_on_gpu):
# All operations of type "MatMul" constructed in this context
# will be placed on GPU 0; all other operations will be placed
# on CPU 0.
N.B. The device scope may be overridden by op wrappers or other library code. For example, a variable assignment op v.assign() must be colocated with the tf.Variable v, and incompatible device scopes will be ignored.
##### Args:
• device_name_or_function: The device name or function to use in the context.
##### Returns:
A context manager that specifies the default device to use for newly created ops.
#### tf.Graph.name_scope(name)
Returns a context manager that creates hierarchical names for operations.
A graph maintains a stack of name scopes. A with name_scope(...): statement pushes a new name onto the stack for the lifetime of the context.
The name argument will be interpreted as follows:
• A string (not ending with '/') will create a new name scope, in which name is appended to the prefix of all operations created in the context. If name has been used before, it will be made unique by calling self.unique_name(name).
• A scope previously captured from a with g.name_scope(...) as scope: statement will be treated as an "absolute" name scope, which makes it possible to re-enter existing scopes.
• A value of None or the empty string will reset the current name scope to the top-level (empty) name scope.
For example:
with tf.Graph().as_default() as g:
c = tf.constant(5.0, name="c")
assert c.op.name == "c"
c_1 = tf.constant(6.0, name="c")
assert c_1.op.name == "c_1"
# Creates a scope called "nested"
with g.name_scope("nested") as scope:
nested_c = tf.constant(10.0, name="c")
assert nested_c.op.name == "nested/c"
# Creates a nested scope called "inner".
with g.name_scope("inner"):
nested_inner_c = tf.constant(20.0, name="c")
assert nested_inner_c.op.name == "nested/inner/c"
# Create a nested scope called "inner_1".
with g.name_scope("inner"):
nested_inner_1_c = tf.constant(30.0, name="c")
assert nested_inner_1_c.op.name == "nested/inner_1/c"
# Treats scope as an absolute name scope, and
# switches to the "nested/" scope.
with g.name_scope(scope):
nested_d = tf.constant(40.0, name="d")
assert nested_d.op.name == "nested/d"
with g.name_scope(""):
e = tf.constant(50.0, name="e")
assert e.op.name == "e"
The name of the scope itself can be captured by with g.name_scope(...) as scope:, which stores the name of the scope in the variable scope. This value can be used to name an operation that represents the overall result of executing the ops in a scope. For example:
inputs = tf.constant(...)
with g.name_scope('my_layer') as scope:
weights = tf.Variable(..., name="weights")
biases = tf.Variable(..., name="biases")
affine = tf.matmul(inputs, weights) + biases
output = tf.nn.relu(affine, name=scope)
NOTE: This constructor validates the given name. Valid scope names match one of the following regular expressions:
[A-Za-z0-9.][A-Za-z0-9_.\\-/]* (for scopes at the root)
[A-Za-z0-9_.\\-/]* (for other scopes)
##### Args:
• name: A name for the scope.
##### Returns:
A context manager that installs name as a new name scope.
##### Raises:
• ValueError: If name is not a valid scope name. The rules are the
A Graph instance supports an arbitrary number of "collections" that are identified by name. For convenience when building a large graph, collections can store groups of related objects: for example, the tf.Variable uses a collection (named tf.GraphKeys.VARIABLES) for all variables that are created during the construction of a graph. The caller may define additional collections by specifying a new name.
#### tf.Graph.add_to_collection(name, value)
Stores value in the collection with the given name.
Note that collections are not sets, so it is possible to add a value to a collection several times.
##### Args:
• name: The key for the collection. The GraphKeys class contains many standard names for collections.
• value: The value to add to the collection.
#### tf.Graph.add_to_collections(names, value)
Stores value in the collections given by names.
Note that collections are not sets, so it is possible to add a value to a collection several times. This function makes sure that duplicates in names are ignored, but it will not check for pre-existing membership of value in any of the collections in names.
names can be any iterable, but if names is a string, it is treated as a single collection name.
##### Args:
• names: The keys for the collections to add to. The GraphKeys class contains many standard names for collections.
• value: The value to add to the collections.
#### tf.Graph.get_collection(name, scope=None)
Returns a list of values in the collection with the given name.
This is different from get_collection_ref() which always returns the actual collection list if it exists in that it returns a new list each time it is called.
##### Args:
• name: The key for the collection. For example, the GraphKeys class contains many standard names for collections.
• scope: (Optional.) If supplied, the resulting list is filtered to include only items whose name attribute matches using re.match. Items without a name attribute are never returned if a scope is supplied and the choice or re.match means that a scope without special tokens filters by prefix.
##### Returns:
The list of values in the collection with the given name, or an empty list if no value has been added to that collection. The list contains the values in the order under which they were collected.
#### tf.Graph.get_collection_ref(name)
Returns a list of values in the collection with the given name.
If the collection exists, this returns the list itself, which can be modified in place to change the collection. If the collection does not exist, it is created as an empty list and the list is returned.
This is different from get_collection() which always returns a copy of the collection list if it exists and never creates an empty collection.
##### Args:
• name: The key for the collection. For example, the GraphKeys class contains many standard names for collections.
##### Returns:
The list of values in the collection with the given name, or an empty list if no value has been added to that collection.
#### tf.Graph.as_graph_element(obj, allow_tensor=True, allow_operation=True)
Returns the object referred to by obj, as an Operation or Tensor.
This function validates that obj represents an element of this graph, and gives an informative error message if it is not.
This function is the canonical way to get/validate an object of one of the allowed types from an external argument reference in the Session API.
This method may be called concurrently from multiple threads.
##### Args:
• obj: A Tensor, an Operation, or the name of a tensor or operation. Can also be any object with an _as_graph_element() method that returns a value of one of these types.
• allow_tensor: If true, obj may refer to a Tensor.
• allow_operation: If true, obj may refer to an Operation.
##### Returns:
The Tensor or Operation in the Graph corresponding to obj.
##### Raises:
• TypeError: If obj is not a type we support attempting to convert to types.
• ValueError: If obj is of an appropriate type but invalid. For example, an invalid string.
• KeyError: If obj is not an object in the graph.
#### tf.Graph.get_operation_by_name(name)
Returns the Operation with the given name.
This method may be called concurrently from multiple threads.
##### Args:
• name: The name of the Operation to return.
##### Returns:
The Operation with the given name.
##### Raises:
• TypeError: If name is not a string.
• KeyError: If name does not correspond to an operation in this graph.
#### tf.Graph.get_tensor_by_name(name)
Returns the Tensor with the given name.
This method may be called concurrently from multiple threads.
##### Args:
• name: The name of the Tensor to return.
##### Returns:
The Tensor with the given name.
##### Raises:
• TypeError: If name is not a string.
• KeyError: If name does not correspond to a tensor in this graph.
#### tf.Graph.get_operations()
Return the list of operations in the graph.
You can modify the operations in place, but modifications to the list such as inserts/delete have no effect on the list of operations known to the graph.
This method may be called concurrently from multiple threads.
##### Returns:
A list of Operations.
#### tf.Graph.seed
The graph-level random seed of this graph.
#### tf.Graph.unique_name(name, mark_as_used=True)
Return a unique operation name for name.
unique_name is used to generate structured names, separated by "/", to help identify operations when debugging a graph. Operation names are displayed in error messages reported by the TensorFlow runtime, and in various visualization tools such as TensorBoard.
If mark_as_used is set to True, which is the default, a new unique name is created and marked as in use. If it's set to False, the unique name is returned without actually being marked as used. This is useful when the caller simply wants to know what the name to be created will be.
##### Args:
• name: The name for an operation.
• mark_as_used: Whether to mark this name as being used.
##### Returns:
A string to be passed to create_op() that will be used to name the operation being created.
#### tf.Graph.version
Returns a version number that increases as ops are added to the graph.
Note that this is unrelated to the GraphDef version.
#### tf.Graph.graph_def_versions
The GraphDef version information of this graph.
For details on the meaning of each version, see [GraphDef] (https://www.tensorflow.org/code/tensorflow/core/framework/graph.proto).
##### Returns:
A VersionDef.
#### tf.Graph.create_op(op_type, inputs, dtypes, input_types=None, name=None, attrs=None, op_def=None, compute_shapes=True, compute_device=True)
Creates an Operation in this graph.
This is a low-level interface for creating an Operation. Most programs will not call this method directly, and instead use the Python op constructors, such as tf.constant(), which add ops to the default graph.
##### Args:
• op_type: The Operation type to create. This corresponds to the OpDef.name field for the proto that defines the operation.
• inputs: A list of Tensor objects that will be inputs to the Operation.
• dtypes: A list of DType objects that will be the types of the tensors that the operation produces.
• input_types: (Optional.) A list of DTypes that will be the types of the tensors that the operation consumes. By default, uses the base DType of each input in inputs. Operations that expect reference-typed inputs must specify input_types explicitly.
• name: (Optional.) A string name for the operation. If not specified, a name is generated based on op_type.
• attrs: (Optional.) A dictionary where the key is the attribute name (a string) and the value is the respective attr attribute of the NodeDef proto that will represent the operation (an AttrValue proto).
• op_def: (Optional.) The OpDef proto that describes the op_type that the operation will have.
• compute_shapes: (Optional.) If True, shape inference will be performed to compute the shapes of the outputs.
• compute_device: (Optional.) If True, device functions will be executed to compute the device property of the Operation.
##### Raises:
• TypeError: if any of the inputs is not a Tensor.
• ValueError: if colocation conflicts with existing device assignment.
##### Returns:
An Operation object.
#### tf.Graph.gradient_override_map(op_type_map)
EXPERIMENTAL: A context manager for overriding gradient functions.
This context manager can be used to override the gradient function that will be used for ops within the scope of the context.
For example:
@tf.RegisterGradient("CustomSquare")
# ...
with tf.Graph().as_default() as g:
c = tf.constant(5.0)
s_1 = tf.square(c) # Uses the default gradient for tf.square.
s_2 = tf.square(s_2) # Uses _custom_square_grad to compute the
# gradient of s_2.
##### Args:
• op_type_map: A dictionary mapping op type strings to alternative op type strings.
##### Returns:
A context manager that sets the alternative op type to be used for one or more ops created in that context.
##### Raises:
• TypeError: If op_type_map is not a dictionary mapping strings to strings.
#### tf.Graph.colocate_with(op, ignore_existing=False)
Returns a context manager that specifies an op to colocate with.
For example:
a = tf.Variable([1.0])
with g.colocate_with(a):
b = tf.constant(1.0)
c = tf.add(a, b)
b and c will always be colocated with a, no matter where a is eventually placed.
##### Args:
• op: The op to colocate all created ops with.
• ignore_existing: If true, only applies colocation of this op within the context, rather than applying all colocation properties on the stack.
##### Raises:
• ValueError: if op is None.
##### Yields:
A context manager that specifies the op with which to colocate newly created ops.
#### tf.Graph.container(container_name)
Returns a context manager that specifies the resource container to use.
Stateful operations, such as variables and queues, can maintain their states on devices so that they can be shared by multiple processes. A resource container is a string name under which these stateful operations are tracked. These resources can be released or cleared with tf.Session.reset().
For example:
with g.container('experiment0'):
# All stateful Operations constructed in this context will be placed
# in resource container "experiment0".
v1 = tf.Variable([1.0])
v2 = tf.Variable([2.0])
with g.container("experiment1"):
# All stateful Operations constructed in this context will be
# placed in resource container "experiment1".
v3 = tf.Variable([3.0])
q1 = tf.FIFOQueue(10, tf.float32)
# All stateful Operations constructed in this context will be
# be created in the "experiment0".
v4 = tf.Variable([4.0])
q1 = tf.FIFOQueue(20, tf.float32)
with g.container(""):
# All stateful Operations constructed in this context will be
# be placed in the default resource container.
v5 = tf.Variable([5.0])
q3 = tf.FIFOQueue(30, tf.float32)
# Resets container "experiment0", after which the state of v1, v2, v4, q1
# will become undefined (such as uninitialized).
tf.Session.reset(target, ["experiment0"])
##### Args:
• container_name: container name string.
##### Returns:
A context manager for defining resource containers for stateful ops, yields the container name.
#### tf.Graph.get_all_collection_keys()
Returns a list of collections used in this graph.
#### tf.Graph.is_feedable(tensor)
Returns True if and only if tensor is feedable.
#### tf.Graph.is_fetchable(tensor_or_op)
Returns True if and only if tensor_or_op is fetchable.
#### tf.Graph.prevent_feeding(tensor)
Marks the given tensor as unfeedable in this graph.
#### tf.Graph.prevent_fetching(op)
Marks the given op as unfetchable in this graph.
### class tf.Operation
Represents a graph node that performs computation on tensors.
An Operation is a node in a TensorFlow Graph that takes zero or more Tensor objects as input, and produces zero or more Tensor objects as output. Objects of type Operation are created by calling a Python op constructor (such as tf.matmul()) or Graph.create_op().
For example c = tf.matmul(a, b) creates an Operation of type "MatMul" that takes tensors a and b as input, and produces c as output.
After the graph has been launched in a session, an Operation can be executed by passing it to Session.run(). op.run() is a shortcut for calling tf.get_default_session().run(op).
#### tf.Operation.name
The full name of this operation.
#### tf.Operation.type
The type of the op (e.g. "MatMul").
#### tf.Operation.inputs
The list of Tensor objects representing the data inputs of this op.
#### tf.Operation.control_inputs
The Operation objects on which this op has a control dependency.
Before this op is executed, TensorFlow will ensure that the operations in self.control_inputs have finished executing. This mechanism can be used to run ops sequentially for performance reasons, or to ensure that the side effects of an op are observed in the correct order.
##### Returns:
A list of Operation objects.
#### tf.Operation.outputs
The list of Tensor objects representing the outputs of this op.
#### tf.Operation.device
The name of the device to which this op has been assigned, if any.
##### Returns:
The string name of the device to which this op has been assigned, or an empty string if it has not been assigned to a device.
#### tf.Operation.graph
The Graph that contains this operation.
#### tf.Operation.run(feed_dict=None, session=None)
Runs this operation in a Session.
Calling this method will execute all preceding operations that produce the inputs needed for this operation.
N.B. Before invoking Operation.run(), its graph must have been launched in a session, and either a default session must be available, or session must be specified explicitly.
##### Args:
• feed_dict: A dictionary that maps Tensor objects to feed values. See Session.run() for a description of the valid feed values.
• session: (Optional.) The Session to be used to run to this operation. If none, the default session will be used.
#### tf.Operation.get_attr(name)
Returns the value of the attr of this op with the given name.
##### Args:
• name: The name of the attr to fetch.
##### Returns:
The value of the attr, as a Python object.
##### Raises:
• ValueError: If this op does not have an attr with the given name.
#### tf.Operation.traceback
Returns the call stack from when this operation was constructed.
#### tf.Operation.__init__(node_def, g, inputs=None, output_types=None, control_inputs=None, input_types=None, original_op=None, op_def=None) {:#Operation.init}
Creates an Operation.
NOTE: This constructor validates the name of the Operation (passed as node_def.name). Valid Operation names match the following regular expression:
[A-Za-z0-9.][A-Za-z0-9_.\-/]*
##### Args:
• node_def: node_def_pb2.NodeDef. NodeDef for the Operation. Used for attributes of node_def_pb2.NodeDef, typically name, op, and device. The input attribute is irrelevant here as it will be computed when generating the model.
• g: Graph. The parent graph.
• inputs: list of Tensor objects. The inputs to this Operation.
• output_types: list of DType objects. List of the types of the Tensors computed by this operation. The length of this list indicates the number of output endpoints of the Operation.
• control_inputs: list of operations or tensors from which to have a control dependency.
• input_types: List of DType objects representing the types of the tensors accepted by the Operation. By default uses [x.dtype.base_dtype for x in inputs]. Operations that expect reference-typed inputs must specify these explicitly.
• original_op: Optional. Used to associate the new Operation with an existing Operation (for example, a replica with the op that was replicated).
• op_def: Optional. The op_def_pb2.OpDef proto that describes the op type that this Operation represents.
##### Raises:
• TypeError: if control inputs are not Operations or Tensors, or if node_def is not a NodeDef, or if g is not a Graph, or if inputs are not tensors, or if inputs and input_types are incompatible.
• ValueError: if the node_def name is not valid.
#### tf.Operation.colocation_groups()
Returns the list of colocation groups of the op.
#### tf.Operation.node_def
Returns a serialized NodeDef representation of this operation.
##### Returns:
A NodeDef protocol buffer.
#### tf.Operation.op_def
Returns the OpDef proto that represents the type of this op.
##### Returns:
An OpDef protocol buffer.
#### tf.Operation.values()
DEPRECATED: Use outputs.
### class tf.Tensor
Represents one of the outputs of an Operation.
Note: the Tensor class will be replaced by Output in the future. Currently these two are aliases for each other.
A Tensor is a symbolic handle to one of the outputs of an Operation. It does not hold the values of that operation's output, but instead provides a means of computing those values in a TensorFlow Session.
This class has two primary purposes:
1. A Tensor can be passed as an input to another Operation. This builds a dataflow connection between operations, which enables TensorFlow to execute an entire Graph that represents a large, multi-step computation.
2. After the graph has been launched in a session, the value of the Tensor can be computed by passing it to Session.run(). t.eval() is a shortcut for calling tf.get_default_session().run(t).
In the following example, c, d, and e are symbolic Tensor objects, whereas result is a numpy array that stores a concrete value:
# Build a dataflow graph.
c = tf.constant([[1.0, 2.0], [3.0, 4.0]])
d = tf.constant([[1.0, 1.0], [0.0, 1.0]])
e = tf.matmul(c, d)
# Construct a Session to execute the graph.
sess = tf.Session()
# Execute the graph and store the value that e represents in result.
result = sess.run(e)
#### tf.Tensor.dtype
The DType of elements in this tensor.
#### tf.Tensor.name
The string name of this tensor.
#### tf.Tensor.value_index
The index of this tensor in the outputs of its Operation.
#### tf.Tensor.graph
The Graph that contains this tensor.
#### tf.Tensor.op
The Operation that produces this tensor as an output.
#### tf.Tensor.consumers()
Returns a list of Operations that consume this tensor.
##### Returns:
A list of Operations.
#### tf.Tensor.eval(feed_dict=None, session=None)
Evaluates this tensor in a Session.
Calling this method will execute all preceding operations that produce the inputs needed for the operation that produces this tensor.
N.B. Before invoking Tensor.eval(), its graph must have been launched in a session, and either a default session must be available, or session must be specified explicitly.
##### Args:
• feed_dict: A dictionary that maps Tensor objects to feed values. See Session.run() for a description of the valid feed values.
• session: (Optional.) The Session to be used to evaluate this tensor. If none, the default session will be used.
##### Returns:
A numpy array corresponding to the value of this tensor.
#### tf.Tensor.get_shape()
Returns the TensorShape that represents the shape of this tensor.
The shape is computed using shape inference functions that are registered for each Operation type using tf.RegisterShape. See TensorShape for more details of what a shape represents.
The inferred shape of a tensor is used to provide shape information without having to launch the graph in a session. This can be used for debugging, and providing early error messages. For example:
c = tf.constant([[1.0, 2.0, 3.0], [4.0, 5.0, 6.0]])
print(c.get_shape())
==> TensorShape([Dimension(2), Dimension(3)])
d = tf.constant([[1.0, 0.0], [0.0, 1.0], [1.0, 0.0], [0.0, 1.0]])
print(d.get_shape())
==> TensorShape([Dimension(4), Dimension(2)])
# Raises a ValueError, because c and d do not have compatible
# inner dimensions.
e = tf.matmul(c, d)
f = tf.matmul(c, d, transpose_a=True, transpose_b=True)
print(f.get_shape())
==> TensorShape([Dimension(3), Dimension(4)])
In some cases, the inferred shape may have unknown dimensions. If the caller has additional information about the values of these dimensions, Tensor.set_shape() can be used to augment the inferred shape.
##### Returns:
A TensorShape representing the shape of this tensor.
#### tf.Tensor.set_shape(shape)
Updates the shape of this tensor.
This method can be called multiple times, and will merge the given shape with the current shape of this tensor. It can be used to provide additional information about the shape of this tensor that cannot be inferred from the graph alone. For example, this can be used to provide additional information about the shapes of images:
_, image_data = tf.TFRecordReader(...).read(...)
image = tf.image.decode_png(image_data, channels=3)
# The height and width dimensions of image are data dependent, and
# cannot be computed without executing the op.
print(image.get_shape())
==> TensorShape([Dimension(None), Dimension(None), Dimension(3)])
# We know that each image in this dataset is 28 x 28 pixels.
image.set_shape([28, 28, 3])
print(image.get_shape())
==> TensorShape([Dimension(28), Dimension(28), Dimension(3)])
##### Args:
• shape: A TensorShape representing the shape of this tensor.
##### Raises:
• ValueError: If shape is not compatible with the current shape of this tensor.
#### tf.Tensor.__abs__(x, name=None) {:#Tensor.abs}
Computes the absolute value of a tensor.
Given a tensor of real numbers x, this operation returns a tensor containing the absolute value of each element in x. For example, if x is an input element and y is an output element, this operation computes $$y = |x|$$.
See tf.complex_abs() to compute the absolute value of a complex number.
##### Args:
• x: A Tensor or SparseTensor of type float32, float64, int32, or int64.
• name: A name for the operation (optional).
##### Returns:
A Tensor or SparseTensor the same size and type as x with absolute values.
#### tf.Tensor.__add__(x, y) {:#Tensor.add}
Returns x + y element-wise.
NOTE: Add supports broadcasting. AddN does not. More about broadcasting here
##### Args:
• x: A Tensor. Must be one of the following types: half, float32, float64, uint8, int8, int16, int32, int64, complex64, complex128, string.
• y: A Tensor. Must have the same type as x.
• name: A name for the operation (optional).
##### Returns:
A Tensor. Has the same type as x.
#### tf.Tensor.__and__(x, y) {:#Tensor.and}
Returns the truth value of x AND y element-wise.
NOTE: LogicalAnd supports broadcasting. More about broadcasting here
##### Args:
• x: A Tensor of type bool.
• y: A Tensor of type bool.
• name: A name for the operation (optional).
##### Returns:
A Tensor of type bool.
#### tf.Tensor.__bool__() {:#Tensor.bool}
Dummy method to prevent a tensor from being used as a Python bool.
This overload raises a TypeError when the user inadvertently treats a Tensor as a boolean (e.g. in an if statement). For example:
if tf.constant(True): # Will raise.
# ...
if tf.constant(5) < tf.constant(7): # Will raise.
# ...
##### Raises:
TypeError.
#### tf.Tensor.__div__(x, y) {:#Tensor.div}
Returns x / y element-wise.
NOTE: Div supports broadcasting. More about broadcasting here
##### Args:
• x: A Tensor. Must be one of the following types: half, float32, float64, uint8, int8, uint16, int16, int32, int64, complex64, complex128.
• y: A Tensor. Must have the same type as x.
• name: A name for the operation (optional).
##### Returns:
A Tensor. Has the same type as x.
#### tf.Tensor.__floordiv__(x, y) {:#Tensor.floordiv}
Divides x / y elementwise, rounding down for floating point.
The same as tf.div(x,y) for integers, but uses tf.floor(tf.div(x,y)) for floating point arguments so that the result is always an integer (though possibly an integer represented as floating point). This op is generated by x // y floor division in Python 3 and in Python 2.7 with from __future__ import division.
Note that for efficiency, floordiv uses C semantics for negative numbers (unlike Python and Numpy).
x and y must have the same type, and the result will have the same type as well.
##### Args:
• x: Tensor numerator of real numeric type.
• y: Tensor denominator of real numeric type.
• name: A name for the operation (optional).
##### Returns:
x / y rounded down (except possibly towards zero for negative integers).
##### Raises:
• TypeError: If the inputs are complex.
#### tf.Tensor.__ge__(x, y, name=None) {:#Tensor.ge}
Returns the truth value of (x >= y) element-wise.
NOTE: GreaterEqual supports broadcasting. More about broadcasting here
##### Args:
• x: A Tensor. Must be one of the following types: float32, float64, int32, int64, uint8, int16, int8, uint16, half.
• y: A Tensor. Must have the same type as x.
• name: A name for the operation (optional).
##### Returns:
A Tensor of type bool.
#### tf.Tensor.__getitem__(tensor, slice_spec, var=None) {:#Tensor.getitem}
This operation extracts the specified region from the tensor. The notation is similar to NumPy with the restriction that currently only support basic indexing. That means that using a tensor as input is not currently allowed
Some useful examples:
# strip leading and trailing 2 elements
foo = tf.constant([1,2,3,4,5,6])
print(foo[2:-2].eval()) # => [3,4]
# skip every row and reverse every column
foo = tf.constant([[1,2,3], [4,5,6], [7,8,9]])
print(foo[::2,::-1].eval()) # => [[3,2,1], [9,8,7]]
# Insert another dimension
foo = tf.constant([[1,2,3], [4,5,6], [7,8,9]])
print(foo[tf.newaxis, :, :].eval()) # => [[[3,2,1], [9,8,7]]]
print(foo[:, tf.newaxis, :].eval()) # => [[[3,2,1]], [[9,8,7]]]
print(foo[:, :, tf.newaxis].eval()) # => [[[3],[2],[1]], [[9],[8],[7]]]
# Ellipses (3 equivalent operations)
print(foo[tf.newaxis, :, :].eval()) # => [[[3,2,1], [9,8,7]]]
print(foo[tf.newaxis, ...].eval()) # => [[[3,2,1], [9,8,7]]]
print(foo[tf.newaxis].eval()) # => [[[3,2,1], [9,8,7]]]
##### Notes:
• tf.newaxis is None as in NumPy.
• An implicit ellipsis is placed at the end of the slice_spec
• NumPy advanced indexing is currently not supported.
##### Args:
• tensor: An ops.Tensor object.
• slice_spec: The arguments to Tensor.getitem.
• var: In the case of variable slice assignment, the Variable object to slice (i.e. tensor is the read-only view of this variable).
##### Returns:
The appropriate slice of "tensor", based on "slice_spec".
##### Raises:
• ValueError: If a slice range is negative size.
• TypeError: If the slice indices aren't int, slice, or Ellipsis.
#### tf.Tensor.__gt__(x, y, name=None) {:#Tensor.gt}
Returns the truth value of (x > y) element-wise.
NOTE: Greater supports broadcasting. More about broadcasting here
##### Args:
• x: A Tensor. Must be one of the following types: float32, float64, int32, int64, uint8, int16, int8, uint16, half.
• y: A Tensor. Must have the same type as x.
• name: A name for the operation (optional).
##### Returns:
A Tensor of type bool.
#### tf.Tensor.__init__(op, value_index, dtype) {:#Tensor.init}
Creates a new Tensor.
##### Args:
• op: An Operation. Operation that computes this tensor.
• value_index: An int. Index of the operation's endpoint that produces this tensor.
• dtype: A DType. Type of elements stored in this tensor.
##### Raises:
• TypeError: If the op is not an Operation.
#### tf.Tensor.__invert__(x, name=None) {:#Tensor.invert}
Returns the truth value of NOT x element-wise.
##### Args:
• x: A Tensor of type bool.
• name: A name for the operation (optional).
##### Returns:
A Tensor of type bool.
#### tf.Tensor.__iter__() {:#Tensor.iter}
Dummy method to prevent iteration. Do not call.
NOTE(mrry): If we register getitem as an overloaded operator, Python will valiantly attempt to iterate over the Tensor from 0 to infinity. Declaring this method prevents this unintended behavior.
##### Raises:
• TypeError: when invoked.
#### tf.Tensor.__le__(x, y, name=None) {:#Tensor.le}
Returns the truth value of (x <= y) element-wise.
NOTE: LessEqual supports broadcasting. More about broadcasting here
##### Args:
• x: A Tensor. Must be one of the following types: float32, float64, int32, int64, uint8, int16, int8, uint16, half.
• y: A Tensor. Must have the same type as x.
• name: A name for the operation (optional).
##### Returns:
A Tensor of type bool.
#### tf.Tensor.__lt__(x, y, name=None) {:#Tensor.lt}
Returns the truth value of (x < y) element-wise.
NOTE: Less supports broadcasting. More about broadcasting here
##### Args:
• x: A Tensor. Must be one of the following types: float32, float64, int32, int64, uint8, int16, int8, uint16, half.
• y: A Tensor. Must have the same type as x.
• name: A name for the operation (optional).
##### Returns:
A Tensor of type bool.
#### tf.Tensor.__mod__(x, y) {:#Tensor.mod}
Returns element-wise remainder of division.
NOTE: Mod supports broadcasting. More about broadcasting here
##### Args:
• x: A Tensor. Must be one of the following types: int32, int64, float32, float64.
• y: A Tensor. Must have the same type as x.
• name: A name for the operation (optional).
##### Returns:
A Tensor. Has the same type as x.
#### tf.Tensor.__mul__(x, y) {:#Tensor.mul}
Dispatches cwise mul for "DenseDense" and "DenseSparse".
#### tf.Tensor.__neg__(x, name=None) {:#Tensor.neg}
Computes numerical negative value element-wise.
I.e., $$y = -x$$.
##### Args:
• x: A Tensor. Must be one of the following types: half, float32, float64, int32, int64, complex64, complex128.
• name: A name for the operation (optional).
##### Returns:
A Tensor. Has the same type as x.
#### tf.Tensor.__nonzero__() {:#Tensor.nonzero}
Dummy method to prevent a tensor from being used as a Python bool.
This is the Python 2.x counterpart to __bool__() above.
##### Raises:
TypeError.
#### tf.Tensor.__or__(x, y) {:#Tensor.or}
Returns the truth value of x OR y element-wise.
NOTE: LogicalOr supports broadcasting. More about broadcasting here
##### Args:
• x: A Tensor of type bool.
• y: A Tensor of type bool.
• name: A name for the operation (optional).
##### Returns:
A Tensor of type bool.
#### tf.Tensor.__pow__(x, y) {:#Tensor.pow}
Computes the power of one value to another.
Given a tensor x and a tensor y, this operation computes $$x^y$$ for corresponding elements in x and y. For example:
# tensor 'x' is [[2, 2], [3, 3]]
# tensor 'y' is [[8, 16], [2, 3]]
tf.pow(x, y) ==> [[256, 65536], [9, 27]]
##### Args:
• x: A Tensor of type float32, float64, int32, int64, complex64, or complex128.
• y: A Tensor of type float32, float64, int32, int64, complex64, or complex128.
• name: A name for the operation (optional).
##### Returns:
A Tensor.
#### tf.Tensor.__radd__(y, x) {:#Tensor.radd}
Returns x + y element-wise.
NOTE: Add supports broadcasting. AddN does not. More about broadcasting here
##### Args:
• x: A Tensor. Must be one of the following types: half, float32, float64, uint8, int8, int16, int32, int64, complex64, complex128, string.
• y: A Tensor. Must have the same type as x.
• name: A name for the operation (optional).
##### Returns:
A Tensor. Has the same type as x.
#### tf.Tensor.__rand__(y, x) {:#Tensor.rand}
Returns the truth value of x AND y element-wise.
NOTE: LogicalAnd supports broadcasting. More about broadcasting here
##### Args:
• x: A Tensor of type bool.
• y: A Tensor of type bool.
• name: A name for the operation (optional).
##### Returns:
A Tensor of type bool.
#### tf.Tensor.__rdiv__(y, x) {:#Tensor.rdiv}
Returns x / y element-wise.
NOTE: Div supports broadcasting. More about broadcasting here
##### Args:
• x: A Tensor. Must be one of the following types: half, float32, float64, uint8, int8, uint16, int16, int32, int64, complex64, complex128.
• y: A Tensor. Must have the same type as x.
• name: A name for the operation (optional).
##### Returns:
A Tensor. Has the same type as x.
#### tf.Tensor.__rfloordiv__(y, x) {:#Tensor.rfloordiv}
Divides x / y elementwise, rounding down for floating point.
The same as tf.div(x,y) for integers, but uses tf.floor(tf.div(x,y)) for floating point arguments so that the result is always an integer (though possibly an integer represented as floating point). This op is generated by x // y floor division in Python 3 and in Python 2.7 with from __future__ import division.
Note that for efficiency, floordiv uses C semantics for negative numbers (unlike Python and Numpy).
x and y must have the same type, and the result will have the same type as well.
##### Args:
• x: Tensor numerator of real numeric type.
• y: Tensor denominator of real numeric type.
• name: A name for the operation (optional).
##### Returns:
x / y rounded down (except possibly towards zero for negative integers).
##### Raises:
• TypeError: If the inputs are complex.
#### tf.Tensor.__rmod__(y, x) {:#Tensor.rmod}
Returns element-wise remainder of division.
NOTE: Mod supports broadcasting. More about broadcasting here
##### Args:
• x: A Tensor. Must be one of the following types: int32, int64, float32, float64.
• y: A Tensor. Must have the same type as x.
• name: A name for the operation (optional).
##### Returns:
A Tensor. Has the same type as x.
#### tf.Tensor.__rmul__(y, x) {:#Tensor.rmul}
Dispatches cwise mul for "DenseDense" and "DenseSparse".
#### tf.Tensor.__ror__(y, x) {:#Tensor.ror}
Returns the truth value of x OR y element-wise.
NOTE: LogicalOr supports broadcasting. More about broadcasting here
##### Args:
• x: A Tensor of type bool.
• y: A Tensor of type bool.
• name: A name for the operation (optional).
##### Returns:
A Tensor of type bool.
#### tf.Tensor.__rpow__(y, x) {:#Tensor.rpow}
Computes the power of one value to another.
Given a tensor x and a tensor y, this operation computes $$x^y$$ for corresponding elements in x and y. For example:
# tensor 'x' is [[2, 2], [3, 3]]
# tensor 'y' is [[8, 16], [2, 3]]
tf.pow(x, y) ==> [[256, 65536], [9, 27]]
##### Args:
• x: A Tensor of type float32, float64, int32, int64, complex64, or complex128.
• y: A Tensor of type float32, float64, int32, int64, complex64, or complex128.
• name: A name for the operation (optional).
##### Returns:
A Tensor.
#### tf.Tensor.__rsub__(y, x) {:#Tensor.rsub}
Returns x - y element-wise.
NOTE: Sub supports broadcasting. More about broadcasting here
##### Args:
• x: A Tensor. Must be one of the following types: half, float32, float64, int32, int64, complex64, complex128.
• y: A Tensor. Must have the same type as x.
• name: A name for the operation (optional).
##### Returns:
A Tensor. Has the same type as x.
#### tf.Tensor.__rtruediv__(y, x) {:#Tensor.rtruediv}
Divides x / y elementwise, always producing floating point results.
The same as tf.div for floating point arguments, but casts integer arguments to floating point before dividing so that the result is always floating point. This op is generated by normal x / y division in Python 3 and in Python 2.7 with from __future__ import division. If you want integer division that rounds down, use x // y or tf.floordiv.
x and y must have the same numeric type. If the inputs are floating point, the output will have the same type. If the inputs are integral, the inputs are cast to float32 for int8 and int16 and float64 for int32 and int64 (matching the behavior of Numpy).
##### Args:
• x: Tensor numerator of numeric type.
• y: Tensor denominator of numeric type.
• name: A name for the operation (optional).
##### Returns:
x / y evaluated in floating point.
##### Raises:
• TypeError: If x and y have different dtypes.
#### tf.Tensor.__rxor__(y, x) {:#Tensor.rxor}
x ^ y = (x | y) & ~(x & y).
#### tf.Tensor.__sub__(x, y) {:#Tensor.sub}
Returns x - y element-wise.
NOTE: Sub supports broadcasting. More about broadcasting here
##### Args:
• x: A Tensor. Must be one of the following types: half, float32, float64, int32, int64, complex64, complex128.
• y: A Tensor. Must have the same type as x.
• name: A name for the operation (optional).
##### Returns:
A Tensor. Has the same type as x.
#### tf.Tensor.__truediv__(x, y) {:#Tensor.truediv}
Divides x / y elementwise, always producing floating point results.
The same as tf.div for floating point arguments, but casts integer arguments to floating point before dividing so that the result is always floating point. This op is generated by normal x / y division in Python 3 and in Python 2.7 with from __future__ import division. If you want integer division that rounds down, use x // y or tf.floordiv.
x and y must have the same numeric type. If the inputs are floating point, the output will have the same type. If the inputs are integral, the inputs are cast to float32 for int8 and int16 and float64 for int32 and int64 (matching the behavior of Numpy).
##### Args:
• x: Tensor numerator of numeric type.
• y: Tensor denominator of numeric type.
• name: A name for the operation (optional).
##### Returns:
x / y evaluated in floating point.
##### Raises:
• TypeError: If x and y have different dtypes.
#### tf.Tensor.__xor__(x, y) {:#Tensor.xor}
x ^ y = (x | y) & ~(x & y).
#### tf.Tensor.device
The name of the device on which this tensor will be produced, or None. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.23302800953388214, "perplexity": 5799.836388603108}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-22/segments/1495463608773.42/warc/CC-MAIN-20170527040600-20170527060600-00449.warc.gz"} |
http://mathhelpforum.com/calculus/227126-converting-double-integral-single-integral.html | ## Converting double integral to single integral
As stated on the image, a double integral is converted to a single one. I need to figure out the logic behind it.
Thanks. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9880262017250061, "perplexity": 485.3865889460975}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-18/segments/1461860112228.39/warc/CC-MAIN-20160428161512-00064-ip-10-239-7-51.ec2.internal.warc.gz"} |
https://moodle.org/mod/forum/discuss.php?d=74103 | ## Resource types
Dear everyone,
I notice that files that required to be upload through the Moodle interface can only be upload one at a time. Is there any other way(s) to upload multiple files or even a directory (or maybe even multiple directories that contain files & sub-directories and then after upload into the Moodle directory, it will still retain the directories structure)
Probably we can have this new function/features added into the Moodle system? That would certainly help to save a lot of time rather than upload one file at one time.
Average of ratings: -
Try zipping the files/folders, uploading the zip file to Moodle, and unzipping from there. That should allow you to upload multiple files and complete directory structures.
If you do this, though, be aware that when you upload a single file Moodle checks the name and if necessary changes it to one which won't cause Moodle a problem when you try to access the file (primarily it gets rid of spaces in file names, so Doc 1.doc becomes Doc_1.doc). When you unzip files Moodle doesn't get chance to check the names, so you could end up with problematic file and folder names in your moodledata folder. Just make sure that all your files and folders are suitably named before you zip them, though, and you should be okay.
HTH
Chris
Average of ratings:Useful (3)
You could also try the flashupload hack by Helmut Geppl. It is availiable from
The site is written in german, but I think even the installationguide is written in german as well you could understand it.
I use this tool and it is very useful!
Average of ratings:Useful (2)
below are the link to the web page, and the converted readme file
=========
Moodle Flash upload by Helmut Geppl
(Allows the upload of multiple files in a browser using Flash)
Installation instructions:
1st The contents of the ZIP file completely to $moodledir / files / copy. 2nd The flashupload.php file from the folder "de_utf8" to$ dataroot/lang/de_utf8 / copy
($Dataroot be obtained by the Moodledata directory example: "/ srv / www / moodledata" under Linux Or c: \ moodledata "or" c: \ xampp \ moodledata "replace Windows). For English is the file from the folder "en_utf8" to$ dataroot/lang/en_utf8 / copy
Other translations, there is not. So you have the file from the folder flashupload.php "en_utf8"
In each subdirectory in the directory $dataroot / lang / (eg: ru_utf8 for Russian) copy and adapt. 3rd Backup File$ moodledir / files / index.php (eg copy "index.php.orig" create)
4th $Moodledir / files / index.php modify: (Modified_index.php the file is the file of the Moodle modified version 1.8.3) The file modified_index.php open and the section between / / Modification by hgeppl ... / / Modification by hgeppl Into its own folder in index.php$ Moodledir / files using copy and paste to insert the following:
B) At the end of this function before the line:
Echo "<table border =" 0 \ "....
Copy the section into it.
Done!
======
larry
Average of ratings:Useful (1)
works great thanks !
(moodle 1.9.2)
Average of ratings: -
Is anyone able to give me a better translation of this? I'm ok until I get to editing index.php at which point I get really quite confused.
Mike
Average of ratings: -
Average of ratings: -
Thanks for pointing that out- I now have it working fine
Mike
Average of ratings: -
For some reason I am getting 404s from this in IE but works fine in FF. When you try to upload, the green boxes for the files go red and state 404 error before dissapearing
Anyone got any ideas to fix it?
Thanks,
Mike
Average of ratings: -
In version 2.2.0 of "Moodle Flashupload" there is a fix for this bug. The 404 error occured because IE doesn't interpret the path to the "upload.php" the way FF does.
Helmut
Average of ratings:Useful (1)
Thanks for sorting that, I've just tried to download it but get a 0byte file
Thanks,
Mike
Average of ratings: -
the 0byte file was produced by an error in the cms. I've now fixed the problem.
Helmut
Average of ratings: -
Thanks for that, it does seem to have a bug that it will only upload to a course's root directory Does this happen to everyone or it it because of a mdification I've made to my file upload page?
Thanks,
Mike
Average of ratings: -
I've testet it on several platforms and i didn't have such a problem. If you attach your personalized upload.php, i can help you to solve the problem.
Helmut
(which os, browser and flash-version are you using?)
Average of ratings: -
Find attached. I've added some code to allow the selection of files from parent metacourses.
Thanks,
Mike
Average of ratings: -
i tried your index.php, but without success. Are there any other files you've modified? Can you attach your complete source or mail it to me. Otherwise i won't be able to try your code.
Helmut
Average of ratings: -
I've made modifications to various files, but I'm pretty sure that is the only modified file that has anything to do with uploading files. What errors are you getting?
Thanks,
Mike
Average of ratings: -
i tried your index.php with another moodle-installation (v. 1.9) and uploading works. The first time i tried with an 1.8.2+ version of Moodle (it seems you've version 1.9 or so installed, please correct me if i'm wrong).
Are you really using the new 2.2.0 version of "moodle flashupload" ?
Sorry Mike, i didn't have time to try this earlier..
Average of ratings: -
I'm running 1.9.1 and V2.2.0
It works fine if uploading to a course's root directory, but if I go into a subdirectory and try to upload it goes through all the motions but the file isn't actually there afterwards.
Thanks for looking into it,
Mike
Average of ratings: -
I think I may have found the problem- file permissions.
I sometimes upload large files and folders containing lots of files over ssh, I've just run into the problem again and realised that www-data user didn't have permission to put the files in the sub-folders. I've set the permissions correctly and it now seems to work.
Sorry for wasting you time over me being thick,
Mike
Average of ratings: -
I've installed this module on my hosted site and it seems to work fine until I try uploading files larger than 2Mb. The upload starts and seems to complete its task but nothing shows up on the screen at the end of the process. And yes, I can upload large files (up to 128MB) in my course using standard uploading (for example, in forum posts). I tried checking out the flashupload.php file for specific upload size settings, but there aren't any I can see. Any ideas how to fix this? I am using Moodle 1.9.5+.
EDIT: in the error_log file, I get messages that look like this:
[14-Oct-2009 08:29:38] PHP Warning: POST Content-Length of 9423398 bytes exceeds the limit of 8388608 bytes in Unknown on line 0
My custom PHP.INI file looks like this:
post_max_size = 128M
Processing time and memory load are not any problem at this point, so I didn't add anything to the PHP.INI file in this regard.
EDIT #2: found it, I just had to add a suPHP_ConfigPath parameter in my root .htaccess file so as to have my PHP.INI file settings recurse through my site folder structure. Works fine now!
Average of ratings: -
I just want to say thank you for this wonderful Multiple Files Upload patch/hack. It was easy to install according to the English ReadMe instructions that come with the package and it works like a dream. I installed on a test system yesterday and today I installed it on our production system. (Moodle 1.9.5)
Average of ratings: -
Just a minor tweak... I hated having it at the top of the files page when the other controls were at the bottom, and it should NOT appear on "action" files pages like rename, etc.
To put it in the footer (below other buttons), and only when appropriate, do this hack to files/index.php instead of the hack in the readme.txt:
In function html_footer(), right before the line
print_footer($COURSE); add: //HACK -- MOD: FLASHUPLOAD - START global$wdir,$course,$CFG;
//HACK -- MOD: FLASHUPLOAD - END
Average of ratings: -
Re: Upload of Multiple files (now liniking multiple files as well)
I'm interested in the possibility of LINKING multiple files at once.
Click the tick boxes > multiple link.
A rolls-royce version would give you the option of entering link names and description.
However, it seems the way the resource is written this is not simple.
Has anyone done anything with this? ??
Average of ratings: - | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.45562073588371277, "perplexity": 3371.5261440356944}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-22/segments/1433195036266.4/warc/CC-MAIN-20150601214356-00005-ip-10-180-206-219.ec2.internal.warc.gz"} |
http://mathhelpforum.com/calculus/45796-difficult-limit.html | # Math Help - difficult limit
1. ## difficult limit
I am having trouble proving the following limit. Any help from the experts?
Show that the limit, as x tends towards infinity, of
$\sqrt{x+\sqrt{x+\sqrt{x}}}-\sqrt{x}$
is 1/2.
2. Originally Posted by tombrownington
I am having trouble proving the following limit. Any help from the experts?
Show that the limit, as x tends towards infinity, of
$\sqrt{x+\sqrt{x+\sqrt{x}}}-\sqrt{x}$
is 1/2.
Multiply the numerator and denominator by $\sqrt{x + \sqrt{x + \sqrt{x}}} + \sqrt{x}$. Simplify the resulting expression. Then divide the numerator and denominator by $\sqrt{x}$. Now take the limit.
Edit: I suppose I should have mentioned that the denominator of the original expression is 1 ..... | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 4, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9965875744819641, "perplexity": 383.5251787911841}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-23/segments/1405997860453.15/warc/CC-MAIN-20140722025740-00251-ip-10-33-131-23.ec2.internal.warc.gz"} |
http://www.perlmonks.org/?parent=591988;node_id=3333 | laziness, impatience, and hubris PerlMonks
Comment on
Need Help??
split and join
Regular expressions are used to match delimiters with the split function, to break up strings into a list of substrings. The join function is in some ways the inverse of split. It takes a list of strings and joins them together again, optionally, with a delimiter. We'll discuss split first, and then move on to join.
A simple example...
Let's first consider a simple use of split: split a string on whitespace.
$line = "Bart Lisa Maggie Marge Homer"; @simpsons = split ( /\s/,$line );
# Splits line and uses single whitespaces
# as the delimiter.
[download]
@simpsons now contains "Bart", "", "Lisa", "Maggie", "Marge", and "Homer".
There is an empty element in the list that split placed in @simpsons. That is because \s matched exactly one whitespace character. But in our string, $line, there were two spaces between Bart and Lisa. Split, using single whitespaces as delimiters, created an empty string at the point where two whitespaces were found next to each other. That also includes preceding whitespace. In fact, empty delimiters found anywhere in the string will result in empty strings being returned as part of the list of strings. We can specify a more flexible delimiter that eliminates the creation of an empty string in the list. @simpsons = split ( /\s+/,$line );
#Now splits on one-or-more whitespaces.
[download]
@simpsons now contains "Bart", "Lisa", "Maggie", "Marge", and "Homer", because the delimiter match is seen as one or more whitespaces, multiple whitespaces next to each other are consumed as one delimiter.
Where do delimiters go?
"What does split do with the delimiters?" Usually it discards them, returning only what is found to either side of the delimiters (including empty strings if two delimiters are next to each other, as seen in our first example). Let's examine that point in the following example:
$string = "Just humilityanother humilityPerl humilityhacker."; @japh = split ( /humility/,$string );
[download]
The delimiter is something visible: 'humility'. And after this code executes, @japh contains four strings, "Just ", "another ", "Perl ", and "hacker.". 'humility' bit the bit-bucket, and was tossed aside.
Preserving delimiters
If you want to keep the delimiters you can. Here's an example of how. Hint, you use capturing parenthesis.
$string = "alpha-bravo-charlie-delta-echo-foxtrot"; @list = split ( /(-)/,$string );
[download]
@list now contains "alpha","-", "bravo","-", "charlie", and so on. The parenthesis caused the delimiters to be captured into the list passed to @list right alongside the stuff between the delimiters.
The null delimiter
What happens if the delimiter is indicated to be a null string (a string of zero characters)? Let's find out.
$string = "Monk"; @letters = split ( //,$string );
[download]
Now @letters contains a list of four letters, "M", "o", "n", and "k". If split is given a null string as a delimiter, it splits on each null position in the string, or in other words, every character boundary. The effect is that the split returns a list broken into individual characters of $string. Split's return value Earlier I mentioned that split returns a list. That list, of course, can be stored in an array, and often is. But another use of split is to store its return values in a list of scalars. Take the following code: @mydata = ( "Simpson:Homer:1-800-000-0000:40:M", "Simpson:Marge:1-800-111-1111:38:F", "Simpson:Bart:1-800-222-2222:11:M", "Simpson:Lisa:1-800-333-3333:9:F", "Simpson:Maggie:1-800-444-4444:2:F" ); foreach ( @mydata ) { ($last, $first,$phone, $age ) = split ( /:/ ); print "You may call$age year old $first$last at $phone.\n"; } [download] What happened to the person's sex? It's just discarded because we're only accepting four of the five fields into our list of scalars. And how does split know what string to split up? When split isn't explicitly given a string to split up, it assumes you want to split the contents of$_. That's handy, because foreach aliases $_ to each element (one at a time) of @mydata. Words about Context Put to its normal use, split is used in list context. It may also be used in scalar context, though its use in scalar context is deprecated. In scalar context, split returns the number of fields found, and splits into the @_ array. It's easy to see why that might not be desirable, and thus, why using split in scalar context is frowned upon. The limit argument Split can optionally take a third argument. If you specify a third argument to split, as in @list = split ( /\s+/,$string, 3 ); split returns no more than the number of fields you specify in the third argument. So if you combine that with our previous example.....
( $last,$first, $everything_else) = split ( /:/,$_, 3 );
[download]
Now, $everything_else contains Bart's phone number, his age, and his sex, delimited by ":", because we told split to stop early. If you specify a negative limit value, split understands that as being the same as an arbitrarily large limit. Unspecified split pattern As mentioned before, limit is an optional parameter. If you leave limit off, you may also, optionally, choose to not specify the split string. Leaving out the split string causes split to attempt to split the string contained in$_. And if you leave off the split string (and limit), you may also choose to not specify a delimiter pattern.
If you leave off the pattern, split assumes you want to split on /\s+/. Not specifying a pattern also causes split to skip leading whitespace. It then splits on any whitespace field (of one or more whitespaces), and skips past any trailing whitespace. One special case is when you specify the string literal, " " (a quoted space), which does the same thing as specifying no delimiter at all (no argument).
The star quantifier (zero or more)
Finally, consider what happens if we specify a split delimiter of /\s*/. The quantifier "*" means zero or more of the item it is quantifying. So this split can split on nothing (character boundaries), any amount of whitespace. And remember, delimiters get thrown away. See this in action:
$string = "Hello world!"; @letters = split ( /\s*/,$string );
[download]
@letters now contains "H", "e", "l", "l", "o", "w", "o", "r", "l", "d", and "!".
Notice that the whitespace is gone. You just split $string, character by character (because null matches boundaries), and on whitespace (which gets discarded because it's a delimiter). Using split versus Regular Expressions There are cases where it is equally easy to use a regexp in list context to split a string as it is to use the split function. Consider the following examples: my @list = split /\s+/,$string;
my @list = $string =~ /(\S+)/g; [download] In the first example you're defining what to throw away. In the second, you're defining what to keep. But you're getting the same results. That is a case where it's equally easy to use either syntax. But what if you need to be more specific as to what you keep, and perhaps are a little less concerned with what comes between what you're keeping? That's a situation where a regexp is probably a better choice. See the following example: my @bignumbers =$string =~ /(\d{4,})/g;
[download]
That type of a match would be difficult to accomplish with split. Try not to fall into the pitfall of using one where the other would be handier. In general, if you know what you want to keep, use a regexp. If you know what you want to get rid of, use split. That's an oversimplification, but start there and if you start tearing your hair out over the code, consider taking another approach. There is always more than one way to do it.
That's enough for split, let's take a look at join.
join: Putting it back together
If you're exhausted by the many ways to use split, you can rest assured that join isn't nearly so complicated. We can over-simplify by saying that join, does the inverse of split. If we said that, we would be mostly accurate. But there are no pattern matches going on. Join takes a string that specifies the delimiter to be concatenated between each item in the list supplied by subsequent parameter(s). Where split accommodates delimiters through a regular expression, allowing for different delimiters as long as they match the regexp, join makes no attempt to allow for differing delimiters. You specify the same delimiter for each item in the list being joined, or you specify no delimiter at all. Those are your choices. Easy.
To join a list of scalars together into one colon delimited string, do this:
$string = join ( ':',$last, $first,$phone, $age,$sex );
[download]
Whew, that was easy. You can also join lists contained in arrays:
$string = join ( ':', @array ); [download] Use join to concatenate It turns out that join is the most efficient way to concatenate many strings together at once; better than the '.' operator. How do you do that? Like this: $string = join ( '', @array );
[download]
As any good Perlish function should, join will accept an actual list, not just an array holding a list. So you can say this:
$string = join ( '*', "My", "Name", "Is", "Dave" ); [download] Or even... $string = join ( 'humility', ( qw/My name is Dave/ ) );
[download]
Which puts humility between each word in the list.
By specifying a null delimiter (nothing between the quotes), you're telling join to join up the elements in @array, one after another, with nothing between them. Easy.
Hopefully you've still got some energy left. If you do, dive back into the Tutorial.
In reply to Understanding Split and Join by davido
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Results (321 votes). Check out past polls. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.19163872301578522, "perplexity": 5747.285575962199}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-13/segments/1490218189495.77/warc/CC-MAIN-20170322212949-00180-ip-10-233-31-227.ec2.internal.warc.gz"} |
https://bibbase.org/network/publication/evans-bazilevs-babuka-hughes-nwidthssupinfsandoptimalityratiosforthekversionoftheisogeometricfiniteelementmethod-2009 | n-Widths, sup–infs, and optimality ratios for the k-version of the isogeometric finite element method. Evans, J. A., Bazilevs, Y., Babuška, I., & Hughes, T. J. R. Computer Methods in Applied Mechanics and Engineering, 198(21-26):1726–1741, Elsevier, 2009.
We begin the mathematical study of the k-method utilizing the theory of Kolmogorov n-widths. The k-method is a finite element technique where spline basis functions of higher-order continuity are employed. It is a fundamental feature of the new field of isogeometric analysis. In previous works, it has been shown that using the k-method has many advantages over the classical finite element method in application areas such as structural dynamics, wave propagation, and turbulence. The Kolmogorov n-width and sup–inf were introduced as tools to assess the effectiveness of approximating functions. In this paper, we investigate the approximation properties of the k-method with these tools. Following a review of theoretical results, we conduct a numerical study in which we compute the n-width and sup–inf for a number of one-dimensional cases. This study sheds further light on the approximation properties of the k-method. We finish this paper with a comparison study of the k-method and the classical finite element method and an analysis of the robustness of polynomial approximation.
@Article{ Evans_2009aa,
abstract = {We begin the mathematical study of the k-method utilizing the theory of Kolmogorov n-widths. The k-method is a finite element technique where spline basis functions of higher-order continuity are employed. It is a fundamental feature of the new field of isogeometric analysis. In previous works, it has been shown that using the k-method has many advantages over the classical finite element method in application areas such as structural dynamics, wave propagation, and turbulence. The Kolmogorov n-width and sup–inf were introduced as tools to assess the effectiveness of approximating functions. In this paper, we investigate the approximation properties of the k-method with these tools. Following a review of theoretical results, we conduct a numerical study in which we compute the n-width and sup–inf for a number of one-dimensional cases. This study sheds further light on the approximation properties of the k-method. We finish this paper with a comparison study of the k-method and the classical finite element method and an analysis of the robustness of polynomial approximation. },
author = {Evans, John A. and Bazilevs, Yuri and Babuška, Ivoo and Hughes, Thomas Joseph Robert},
doi = {http://dx.doi.org/10.1016/j.cma.2009.01.021},
file = {Evans_2009aa.pdf},
issn = {0045-7825},
journal = {Computer Methods in Applied Mechanics and Engineering},
keywords = {Sup–inf},
number = {21-26},
pages = {1726--1741},
publisher = {Elsevier},
title = {n-Widths, sup–infs, and optimality ratios for the k-version of the isogeometric finite element method},
volume = {198},
year = {2009},
shortjournal = {Comput. Meth. Appl. Mech. Eng.}
} | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8633842468261719, "perplexity": 884.5410733317881}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-33/segments/1659882573876.92/warc/CC-MAIN-20220820012448-20220820042448-00765.warc.gz"} |
http://mathhelpforum.com/advanced-statistics/37405-probability-estimate-poisson-distribution-print.html | # Probability for estimate/poisson distribution
• May 6th 2008, 10:46 AM
iljitj
Probability for estimate/poisson distribution
Hi
I've searched the forum for topic but I can't seem find one with the same problem, so here goes:
I have Xi given as the number of an occurrence pr quarter.
X1...Xn is independent and Xi~Poisson(a)
I have maximized a for the likelihoodfunction to be [LaTeX ERROR: Convert failed] as an estimation of a.
Now to my question:
For a=1.25 and n=10, what is the probability that a* equals respectively 1.1 and 1.25?
My paper is to be done in a couple of hours, so help would be very much appreciated.. (Smile)
Edit: Even though the couple of hours has gone by, I actually still need som help, so if anyone have a hint or two..?
• May 6th 2008, 01:34 PM
CaptainBlack
Quote:
Originally Posted by iljitj
Hi
I've searched the forum for topic but I can't seem find one with the same problem, so here goes:
I have Xi given as the number of an occurrence pr quarter.
X1...Xn is independent and Xi~Poisson(a)
I have maximized a for the likelihoodfunction to be $a*=\frac{1}{n}\sum{Xi}$ as an estimation of a.
Now to my question:
For a=1.25 and n=10, what is the probability that a* equals respectively 1.1 and 1.25?
My paper is to be done in a couple of hours, so help would be very much appreciated.. (Smile)
Edit: Even though the couple of hours has gone by, I actually still need som help, so if anyone have a hint or two..?
The sum of n Poisson iid RV's with parameter a, is a Poission RV with parameter na.
RonL
• May 6th 2008, 02:09 PM
iljitj
Correct me if I'm wrong, but does that mean that I should do it like this:
$P(X=1.1)=\frac{12.5^{11}}{11!}e^-12.5=0.109$
??
• May 6th 2008, 07:51 PM
CaptainBlack
Quote:
Originally Posted by iljitj
$P(X=1.1)=\frac{12.5^{11}}{11!}e^{-12.5}=0.109$ | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 3, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8596075773239136, "perplexity": 1351.82411845712}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-44/segments/1476988719468.5/warc/CC-MAIN-20161020183839-00509-ip-10-171-6-4.ec2.internal.warc.gz"} |
https://webot.org/info/en/?search=Logistic_function | Standard logistic function where ${\displaystyle L=1,k=1,x_{0}=0}$
A logistic function or logistic curve is a common S-shaped curve ( sigmoid curve) with equation
${\displaystyle f(x)={\frac {L}{1+e^{-k(x-x_{0})}}},}$
where
${\displaystyle x_{0}}$, the ${\displaystyle x}$ value of the function's midpoint;
${\displaystyle L}$, the supremum of the values of the function;
${\displaystyle k}$, the logistic growth rate or steepness of the curve. [1]
For values of ${\displaystyle x}$ in the domain of real numbers from ${\displaystyle -\infty }$ to ${\displaystyle +\infty }$, the S-curve shown on the right is obtained, with the graph of ${\displaystyle f}$ approaching ${\displaystyle L}$ as ${\displaystyle x}$ approaches ${\displaystyle +\infty }$ and approaching zero as ${\displaystyle x}$ approaches ${\displaystyle -\infty }$.
The logistic function finds applications in a range of fields, including biology (especially ecology), biomathematics, chemistry, demography, economics, geoscience, mathematical psychology, probability, sociology, political science, linguistics, statistics, and artificial neural networks. A generalization of the logistic function is the hyperbolastic function of type I.
The standard logistic function, where ${\displaystyle L=1,k=1,x_{0}=0}$, is sometimes simply called the sigmoid. [2] It is also sometimes called the expit, being the inverse of the logit. [3] [4]
## History
Original image of a logistic curve, contrasted with what Verhulst called a "logarithmic curve" (in modern terms, "exponential curve")
The logistic function was introduced in a series of three papers by Pierre François Verhulst between 1838 and 1847, who devised it as a model of population growth by adjusting the exponential growth model, under the guidance of Adolphe Quetelet. [5] Verhulst first devised the function in the mid 1830s, publishing a brief note in 1838, [1] then presented an expanded analysis and named the function in 1844 (published 1845); [a] [6] the third paper adjusted the correction term in his model of Belgian population growth. [7]
The initial stage of growth is approximately exponential (geometric); then, as saturation begins, the growth slows to linear (arithmetic), and at maturity, growth stops. Verhulst did not explain the choice of the term "logistic" (French: logistique), but it is presumably in contrast to the logarithmic curve, [8] [b] and by analogy with arithmetic and geometric. His growth model is preceded by a discussion of arithmetic growth and geometric growth (whose curve he calls a logarithmic curve, instead of the modern term exponential curve), and thus "logistic growth" is presumably named by analogy, logistic being from Ancient Greek: λογῐστῐκός, romanizedlogistikós, a traditional division of Greek mathematics. [c] The term is unrelated to the military and management term logistics, which is instead from French: logis "lodgings", though some believe the Greek term also influenced logistics; see Logistics § Origin for details.
## Mathematical properties
The standard logistic function is the logistic function with parameters ${\displaystyle k=1}$, ${\displaystyle x_{0}=0}$, ${\displaystyle L=1}$, which yields
${\displaystyle f(x)={\frac {1}{1+e^{-x}}}={\frac {e^{x}}{e^{x}+1}}={\frac {1}{2}}+{\frac {1}{2}}\tanh \left({\frac {x}{2}}\right).}$
In practice, due to the nature of the exponential function ${\displaystyle e^{-x}}$, it is often sufficient to compute the standard logistic function for ${\displaystyle x}$ over a small range of real numbers, such as a range contained in [−6, +6], as it quickly converges very close to its saturation values of 0 and 1.
The logistic function has the symmetry property that
${\displaystyle 1-f(x)=f(-x).}$
Thus, ${\displaystyle x\mapsto f(x)-1/2}$ is an odd function.
The logistic function is an offset and scaled hyperbolic tangent function:
${\displaystyle f(x)={\frac {1}{2}}+{\frac {1}{2}}\tanh \left({\frac {x}{2}}\right),}$
or
${\displaystyle \tanh(x)=2f(2x)-1.}$
This follows from
{\displaystyle {\begin{aligned}\tanh(x)&={\frac {e^{x}-e^{-x}}{e^{x}+e^{-x}}}={\frac {e^{x}\cdot \left(1-e^{-2x}\right)}{e^{x}\cdot \left(1+e^{-2x}\right)}}\\&=f(2x)-{\frac {e^{-2x}}{1+e^{-2x}}}=f(2x)-{\frac {e^{-2x}+1-1}{1+e^{-2x}}}=2f(2x)-1.\end{aligned}}}
### Derivative
The logistic function and its first 3 derivatives
The standard logistic function has an easily calculated derivative. The derivative is known as the density of the logistic distribution:
${\displaystyle f(x)={\frac {1}{1+e^{-x}}}={\frac {e^{x}}{1+e^{x}}},}$
${\displaystyle {\frac {\mathrm {d} }{\mathrm {d} x}}f(x)={\frac {e^{x}\cdot (1+e^{x})-e^{x}\cdot e^{x}}{(1+e^{x})^{2}}}={\frac {e^{x}}{(1+e^{x})^{2}}}=f(x){\big (}1-f(x){\big )}}$
The logistic distribution has mean x0 and variance π2/3k2
### Integral
Conversely, its antiderivative can be computed by the substitution ${\displaystyle u=1+e^{x}}$, since ${\displaystyle f(x)={\frac {e^{x}}{1+e^{x}}}={\frac {u'}{u}}}$, so (dropping the constant of integration)
${\displaystyle \int {\frac {e^{x}}{1+e^{x}}}\,dx=\int {\frac {1}{u}}\,du=\ln u=\ln(1+e^{x}).}$
In artificial neural networks, this is known as the softplus function and (with scaling) is a smooth approximation of the ramp function, just as the logistic function (with scaling) is a smooth approximation of the Heaviside step function.
### Logistic differential equation
The standard logistic function is the solution of the simple first-order non-linear ordinary differential equation
${\displaystyle {\frac {d}{dx}}f(x)=f(x){\big (}1-f(x){\big )}}$
with boundary condition ${\displaystyle f(0)=1/2}$. This equation is the continuous version of the logistic map. Note that the reciprocal logistic function is solution to a simple first-order linear ordinary differential equation. [9]
The qualitative behavior is easily understood in terms of the phase line: the derivative is 0 when the function is 1; and the derivative is positive for ${\displaystyle f}$ between 0 and 1, and negative for ${\displaystyle f}$ above 1 or less than 0 (though negative populations do not generally accord with a physical model). This yields an unstable equilibrium at 0 and a stable equilibrium at 1, and thus for any function value greater than 0 and less than 1, it grows to 1.
The logistic equation is a special case of the Bernoulli differential equation and has the following solution:
${\displaystyle f(x)={\frac {e^{x}}{e^{x}+C}}.}$
Choosing the constant of integration ${\displaystyle C=1}$ gives the other well known form of the definition of the logistic curve:
${\displaystyle f(x)={\frac {e^{x}}{e^{x}+1}}={\frac {1}{1+e^{-x}}}.}$
More quantitatively, as can be seen from the analytical solution, the logistic curve shows early exponential growth for negative argument, which reaches to linear growth of slope 1/4 for an argument near 0, then approaches 1 with an exponentially decaying gap.
The logistic function is the inverse of the natural logit function
${\displaystyle \operatorname {logit} p=\log {\frac {p}{1-p}}{\text{ for }}0
and so converts the logarithm of odds into a probability. The conversion from the log-likelihood ratio of two alternatives also takes the form of a logistic curve.
The differential equation derived above is a special case of a general differential equation that only models the sigmoid function for ${\displaystyle x>0}$. In many modeling applications, the more general form [10]
${\displaystyle {\frac {df(x)}{dx}}={\frac {k}{a}}f(x){\big (}a-f(x){\big )},\quad f(0)={\frac {a}{1+e^{kr}}}}$
can be desirable. Its solution is the shifted and scaled sigmoid ${\displaystyle aS{\big (}k(x-r){\big )}}$.
The hyperbolic-tangent relationship leads to another form for the logistic function's derivative:
${\displaystyle {\frac {d}{dx}}f(x)={\frac {1}{4}}\operatorname {sech} ^{2}\left({\frac {x}{2}}\right),}$
which ties the logistic function into the logistic distribution.
### Rotational symmetry about (0, 1/2)
The sum of the logistic function and its reflection about the vertical axis, ${\displaystyle f(-x)}$, is
${\displaystyle {\frac {1}{1+e^{-x}}}+{\frac {1}{1+e^{-(-x)}}}={\frac {e^{x}}{e^{x}+1}}+{\frac {1}{e^{x}+1}}=1.}$
The logistic function is thus rotationally symmetrical about the point (0, 1/2). [11]
## Applications
Link [12] created an extension of Wald's theory of sequential analysis to a distribution-free accumulation of random variables until either a positive or negative bound is first equaled or exceeded. Link [13] derives the probability of first equaling or exceeding the positive boundary as ${\displaystyle 1/(1+e^{-\theta A})}$, the logistic function. This is the first proof that the logistic function may have a stochastic process as its basis. Link [14] provides a century of examples of "logistic" experimental results and a newly derived relation between this probability and the time of absorption at the boundaries.
### In ecology: modeling population growth
Pierre-François Verhulst (1804–1849)
A typical application of the logistic equation is a common model of population growth (see also population dynamics), originally due to Pierre-François Verhulst in 1838, where the rate of reproduction is proportional to both the existing population and the amount of available resources, all else being equal. The Verhulst equation was published after Verhulst had read Thomas Malthus' An Essay on the Principle of Population, which describes the Malthusian growth model of simple (unconstrained) exponential growth. Verhulst derived his logistic equation to describe the self-limiting growth of a biological population. The equation was rediscovered in 1911 by A. G. McKendrick for the growth of bacteria in broth and experimentally tested using a technique for nonlinear parameter estimation. [15] The equation is also sometimes called the Verhulst-Pearl equation following its rediscovery in 1920 by Raymond Pearl (1879–1940) and Lowell Reed (1888–1966) of the Johns Hopkins University. [16] Another scientist, Alfred J. Lotka derived the equation again in 1925, calling it the law of population growth.
Letting ${\displaystyle P}$ represent population size (${\displaystyle N}$ is often used in ecology instead) and ${\displaystyle t}$ represent time, this model is formalized by the differential equation:
${\displaystyle {\frac {dP}{dt}}=rP\left(1-{\frac {P}{K}}\right),}$
where the constant ${\displaystyle r}$ defines the growth rate and ${\displaystyle K}$ is the carrying capacity.
In the equation, the early, unimpeded growth rate is modeled by the first term ${\displaystyle +rP}$. The value of the rate ${\displaystyle r}$ represents the proportional increase of the population ${\displaystyle P}$ in one unit of time. Later, as the population grows, the modulus of the second term (which multiplied out is ${\displaystyle -rP^{2}/K}$) becomes almost as large as the first, as some members of the population ${\displaystyle P}$ interfere with each other by competing for some critical resource, such as food or living space. This antagonistic effect is called the bottleneck, and is modeled by the value of the parameter ${\displaystyle K}$. The competition diminishes the combined growth rate, until the value of ${\displaystyle P}$ ceases to grow (this is called maturity of the population). The solution to the equation (with ${\displaystyle P_{0}}$ being the initial population) is
${\displaystyle P(t)={\frac {KP_{0}e^{rt}}{K+P_{0}\left(e^{rt}-1\right)}}={\frac {K}{1+\left({\frac {K-P_{0}}{P_{0}}}\right)e^{-rt}}},}$
where
${\displaystyle \lim _{t\to \infty }P(t)=K,}$
where ${\displaystyle K}$ is the limiting value of ${\displaystyle P}$, the highest value that the population can reach given infinite time (or come close to reaching in finite time). It is important to stress that the carrying capacity is asymptotically reached independently of the initial value ${\displaystyle P(0)>0}$, and also in the case that ${\displaystyle P(0)>K}$.
In ecology, species are sometimes referred to as ${\displaystyle r}$-strategist or ${\displaystyle K}$-strategist depending upon the selective processes that have shaped their life history strategies. Choosing the variable dimensions so that ${\displaystyle n}$ measures the population in units of carrying capacity, and ${\displaystyle \tau }$ measures time in units of ${\displaystyle 1/r}$, gives the dimensionless differential equation
${\displaystyle {\frac {dn}{d\tau }}=n(1-n).}$
#### Integral
The antiderivative of the ecological form of the logistic function can be computed by the substitution ${\displaystyle u=K+P_{0}\left(e^{rt}-1\right)}$, since ${\displaystyle du=rP_{0}e^{rt}dt}$
${\displaystyle \int {\frac {KP_{0}e^{rt}}{K+P_{0}\left(e^{rt}-1\right)}}\,dt=\int {\frac {K}{r}}{\frac {1}{u}}\,du={\frac {K}{r}}\ln u+C={\frac {K}{r}}\ln \left(K+P_{0}(e^{rt}-1)\right)+C}$
#### Time-varying carrying capacity
Since the environmental conditions influence the carrying capacity, as a consequence it can be time-varying, with ${\displaystyle K(t)>0}$, leading to the following mathematical model:
${\displaystyle {\frac {dP}{dt}}=rP\cdot \left(1-{\frac {P}{K(t)}}\right).}$
A particularly important case is that of carrying capacity that varies periodically with period ${\displaystyle T}$:
${\displaystyle K(t+T)=K(t).}$
It can be shown [17] that in such a case, independently from the initial value ${\displaystyle P(0)>0}$, ${\displaystyle P(t)}$ will tend to a unique periodic solution ${\displaystyle P_{*}(t)}$, whose period is ${\displaystyle T}$.
A typical value of ${\displaystyle T}$ is one year: In such case ${\displaystyle K(t)}$ may reflect periodical variations of weather conditions.
Another interesting generalization is to consider that the carrying capacity ${\displaystyle K(t)}$ is a function of the population at an earlier time, capturing a delay in the way population modifies its environment. This leads to a logistic delay equation, [18] which has a very rich behavior, with bistability in some parameter range, as well as a monotonic decay to zero, smooth exponential growth, punctuated unlimited growth (i.e., multiple S-shapes), punctuated growth or alternation to a stationary level, oscillatory approach to a stationary level, sustainable oscillations, finite-time singularities as well as finite-time death.
### In statistics and machine learning
Logistic functions are used in several roles in statistics. For example, they are the cumulative distribution function of the logistic family of distributions, and they are, a bit simplified, used to model the chance a chess player has to beat their opponent in the Elo rating system. More specific examples now follow.
#### Logistic regression
Logistic functions are used in logistic regression to model how the probability ${\displaystyle p}$ of an event may be affected by one or more explanatory variables: an example would be to have the model
${\displaystyle p=f(a+bx),}$
where ${\displaystyle x}$ is the explanatory variable, ${\displaystyle a}$ and ${\displaystyle b}$ are model parameters to be fitted, and ${\displaystyle f}$ is the standard logistic function.
Logistic regression and other log-linear models are also commonly used in machine learning. A generalisation of the logistic function to multiple inputs is the softmax activation function, used in multinomial logistic regression.
Another application of the logistic function is in the Rasch model, used in item response theory. In particular, the Rasch model forms a basis for maximum likelihood estimation of the locations of objects or persons on a continuum, based on collections of categorical data, for example the abilities of persons on a continuum based on responses that have been categorized as correct and incorrect.
#### Neural networks
Logistic functions are often used in neural networks to introduce nonlinearity in the model or to clamp signals to within a specified interval. A popular neural net element computes a linear combination of its input signals, and applies a bounded logistic function as the activation function to the result; this model can be seen as a "smoothed" variant of the classical threshold neuron.
A common choice for the activation or "squashing" functions, used to clip for large magnitudes to keep the response of the neural network bounded [19] is
${\displaystyle g(h)={\frac {1}{1+e^{-2\beta h}}},}$
which is a logistic function.
These relationships result in simplified implementations of artificial neural networks with artificial neurons. Practitioners caution that sigmoidal functions which are antisymmetric about the origin (e.g. the hyperbolic tangent) lead to faster convergence when training networks with backpropagation. [20]
The logistic function is itself the derivative of another proposed activation function, the softplus.
### In medicine: modeling of growth of tumors
Another application of logistic curve is in medicine, where the logistic differential equation is used to model the growth of tumors. This application can be considered an extension of the above-mentioned use in the framework of ecology (see also the Generalized logistic curve, allowing for more parameters). Denoting with ${\displaystyle X(t)}$ the size of the tumor at time ${\displaystyle t}$, its dynamics are governed by
${\displaystyle X'=r\left(1-{\frac {X}{K}}\right)X,}$
which is of the type
${\displaystyle X'=F(X)X,\quad F'(X)\leq 0,}$
where ${\displaystyle F(X)}$ is the proliferation rate of the tumor.
If a chemotherapy is started with a log-kill effect, the equation may be revised to be
${\displaystyle X'=r\left(1-{\frac {X}{K}}\right)X-c(t)X,}$
where ${\displaystyle c(t)}$ is the therapy-induced death rate. In the idealized case of very long therapy, ${\displaystyle c(t)}$ can be modeled as a periodic function (of period ${\displaystyle T}$) or (in case of continuous infusion therapy) as a constant function, and one has that
${\displaystyle {\frac {1}{T}}\int _{0}^{T}c(t)\,dt>r\to \lim _{t\to +\infty }x(t)=0,}$
i.e. if the average therapy-induced death rate is greater than the baseline proliferation rate, then there is the eradication of the disease. Of course, this is an oversimplified model of both the growth and the therapy (e.g. it does not take into account the phenomenon of clonal resistance).
### In medicine: modeling of a pandemic
A novel infectious pathogen to which a population has no immunity will generally spread exponentially in the early stages, while the supply of susceptible individuals is plentiful. The SARS-CoV-2 virus that causes COVID-19 exhibited exponential growth early in the course of infection in several countries in early 2020. [21] Factors including a lack of susceptible hosts (through the continued spread of infection until it passes the threshold for herd immunity) or reduction in the accessibility of potential hosts through physical distancing measures, may result in exponential-looking epidemic curves first linearizing (replicating the "logarithmic" to "logistic" transition first noted by Pierre-François Verhulst, as noted above) and then reaching a maximal limit. [22]
A logistic function, or related functions (e.g. the Gompertz function) are usually used in a descriptive or phenomenological manner because they fit well not only to the early exponential rise, but to the eventual levelling off of the pandemic as the population develops a herd immunity. This is in contrast to actual models of pandemics which attempt to formulate a description based on the dynamics of the pandemic (e.g. contact rates, incubation times, social distancing, etc.). Some simple models have been developed, however, which yield a logistic solution. [23] [24] [25]
#### Modeling early COVID-19 cases
Generalized logistic function (Richards growth curve) in epidemiological modeling
A generalized logistic function, also called the Richards growth curve, has been applied to model the early phase of the COVID-19 outbreak. [26] The authors fit the generalized logistic function to the cumulative number of infected cases, here referred to as infection trajectory. There are different parameterizations of the generalized logistic function in the literature. One frequently used forms is
${\displaystyle f(t;\theta _{1},\theta _{2},\theta _{3},\xi )={\frac {\theta _{1}}{[1+\xi \exp(-\theta _{2}\cdot (t-\theta _{3}))]^{1/\xi }}}}$
where ${\displaystyle \theta _{1},\theta _{2},\theta _{3}}$ are real numbers, and ${\displaystyle \xi }$ is a positive real number. The flexibility of the curve ${\displaystyle f}$ is due to the parameter ${\displaystyle \xi }$: (i) if ${\displaystyle \xi =1}$ then the curve reduces to the logistic function, and (ii) as ${\displaystyle \xi }$ approaches zero, the curve converges to the Gompertz function. In epidemiological modeling, ${\displaystyle \theta _{1}}$, ${\displaystyle \theta _{2}}$, and ${\displaystyle \theta _{3}}$ represent the final epidemic size, infection rate, and lag phase, respectively. See the right panel for an example infection trajectory when ${\displaystyle (\theta _{1},\theta _{2},\theta _{3})}$ is set to ${\displaystyle (10000,0.2,40)}$.
Extrapolated infection trajectories of 40 countries severely affected by COVID-19 and grand (population) average through May 14th
One of the benefits of using a growth function such as the generalized logistic function in epidemiological modeling is its relatively easy application to the multilevel model framework, where information from different geographic regions can be pooled together.
### In chemistry: reaction models
The concentration of reactants and products in autocatalytic reactions follow the logistic function. The degradation of Platinum group metal-free (PGM-free) oxygen reduction reaction (ORR) catalyst in fuel cell cathodes follows the logistic decay function, [27] suggesting an autocatalytic degradation mechanism.
### In physics: Fermi–Dirac distribution
The logistic function determines the statistical distribution of fermions over the energy states of a system in thermal equilibrium. In particular, it is the distribution of the probabilities that each possible energy level is occupied by a fermion, according to Fermi–Dirac statistics.
### In linguistics: language change
In linguistics, the logistic function can be used to model language change: [28] an innovation that is at first marginal begins to spread more quickly with time, and then more slowly as it becomes more universally adopted.
### In agriculture: modeling crop response
The logistic S-curve can be used for modeling the crop response to changes in growth factors. There are two types of response functions: positive and negative growth curves. For example, the crop yield may increase with increasing value of the growth factor up to a certain level (positive function), or it may decrease with increasing growth factor values (negative function owing to a negative growth factor), which situation requires an inverted S-curve.
S-curve model for crop yield versus depth of water table. [29]
Inverted S-curve model for crop yield versus soil salinity. [30]
### In economics and sociology: diffusion of innovations
The logistic function can be used to illustrate the progress of the diffusion of an innovation through its life cycle.
In The Laws of Imitation (1890), Gabriel Tarde describes the rise and spread of new ideas through imitative chains. In particular, Tarde identifies three main stages through which innovations spread: the first one corresponds to the difficult beginnings, during which the idea has to struggle within a hostile environment full of opposing habits and beliefs; the second one corresponds to the properly exponential take-off of the idea, with ${\displaystyle f(x)=2^{x}}$; finally, the third stage is logarithmic, with ${\displaystyle f(x)=\log(x)}$, and corresponds to the time when the impulse of the idea gradually slows down while, simultaneously new opponent ideas appear. The ensuing situation halts or stabilizes the progress of the innovation, which approaches an asymptote.
In a Sovereign state, the subnational units (constituent states or cities) may use loans to finance their projects. However, this funding source is usually subject to strict legal rules as well as to economy scarcity constraints, specially the resources the banks can lend (due to their equity or Basel limits). These restrictions, which represent a saturation level, along with an exponential rush in an economic competition for money, create a public finance diffusion of credit pleas and the aggregate national response is a sigmoid curve. [31]
In the history of economy, when new products are introduced there is an intense amount of research and development which leads to dramatic improvements in quality and reductions in cost. This leads to a period of rapid industry growth. Some of the more famous examples are: railroads, incandescent light bulbs, electrification, cars and air travel. Eventually, dramatic improvement and cost reduction opportunities are exhausted, the product or process are in widespread use with few remaining potential new customers, and markets become saturated.
Logistic analysis was used in papers by several researchers at the International Institute of Applied Systems Analysis ( IIASA). These papers deal with the diffusion of various innovations, infrastructures and energy source substitutions and the role of work in the economy as well as with the long economic cycle. Long economic cycles were investigated by Robert Ayres (1989). [32] Cesare Marchetti published on long economic cycles and on diffusion of innovations. [33] [34] Arnulf Grübler's book (1990) gives a detailed account of the diffusion of infrastructures including canals, railroads, highways and airlines, showing that their diffusion followed logistic shaped curves. [35]
Carlota Perez used a logistic curve to illustrate the long ( Kondratiev) business cycle with the following labels: beginning of a technological era as irruption, the ascent as frenzy, the rapid build out as synergy and the completion as maturity. [36]
## Notes
1. ^ The paper was presented in 1844, and published in 1845: "(Lu à la séance du 30 novembre 1844)." "(Read at the session of 30 November 1844).", p. 1.
2. ^ Verhulst first refers to arithmetic progression and geometric progression, and refers to the geometric growth curve as a logarithmic curve (confusingly, the modern term is instead exponential curve, which is the inverse). He then calls his curve logistic, in contrast to logarithmic, and compares the logarithmic curve and logistic curve in the figure of his paper.
3. ^ In Ancient Greece, λογῐστῐκός referred to practical computation and accounting, in contrast to ἀριθμητική (arithmētikḗ), the theoretical or philosophical study of numbers. Confusingly, in English, arithmetic refers to practical computation, even though it derives from ἀριθμητική, not λογῐστῐκός. See for example Louis Charles Karpinski, Nicomachus of Gerasa: Introduction to Arithmetic (1926) p. 3: "Arithmetic is fundamentally associated by modern readers, particularly by scientists and mathematicians, with the art of computation. For the ancient Greeks after Pythagoras, however, arithmetic was primarily a philosophical study, having no necessary connection with practical affairs. Indeed the Greeks gave a separate name to the arithmetic of business, λογιστική [accounting or practical logistic] ... In general the philosophers and mathematicians of Greece undoubtedly considered it beneath their dignity to treat of this branch, which probably formed a part of the elementary instruction of children."
## References
1. ^ a b Verhulst, Pierre-François (1838). "Notice sur la loi que la population poursuit dans son accroissement" (PDF). Correspondance Mathématique et Physique. 10: 113–121. Retrieved 3 December 2014.
2. ^
3. ^
4. ^
5. ^ Cramer 2002, pp. 3–5.
6. ^ Verhulst, Pierre-François (1845). "Recherches mathématiques sur la loi d'accroissement de la population" [Mathematical Researches into the Law of Population Growth Increase]. Nouveaux Mémoires de l'Académie Royale des Sciences et Belles-Lettres de Bruxelles. 18: 8. Retrieved 18 February 2013. Nous donnerons le nom de logistique à la courbe [We will give the name logistic to the curve]
7. ^ Verhulst, Pierre-François (1847). "Deuxième mémoire sur la loi d'accroissement de la population". Mémoires de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique. 20: 1–32. Retrieved 18 February 2013.
8. ^ Shulman, Bonnie (1998). "Math-alive! using original sources to teach mathematics in social context". PRIMUS. 8 (March): 1–14. doi: 10.1080/10511979808965879. The diagram clinched it for me: there two curves labeled "Logistique" and "Logarithmique" are drawn on the same axes, and one can see that there is a region where they match almost exactly, and then diverge.
I concluded that Verhulst's intention in naming the curve was indeed to suggest this comparison, and that "logistic" was meant to convey the curve's "log-like" quality.
9. ^ Kocian, Alexander; Carmassi, Giulia; Cela, Fatjon; Incrocci, Luca; Milazzo, Paolo; Chessa, Stefano (7 June 2020). "Bayesian Sigmoid-Type Time Series Forecasting with Missing Data for Greenhouse Crops". Sensors. 20 (11): 3246. Bibcode: 2020Senso..20.3246K. doi:. PMC . PMID 32517314.
10. ^ Kyurkchiev, Nikolay, and Svetoslav Markov. "Sigmoid functions: some approximation and modelling aspects". LAP LAMBERT Academic Publishing, Saarbrucken (2015).
11. ^ Raul Rojas. Neural Networks – A Systematic Introduction (PDF). Retrieved 15 October 2016.
12. ^ S. W. Link, Psychometrika, 1975, 40, 1, 77–105
13. ^ S. W. Link, Attention and Performance VII, 1978, 619–630
14. ^ S. W. Link, The wave theory of difference and similarity (book), Taylor and Francis, 1992
15. ^ A. G. McKendricka; M. Kesava Paia1 (January 1912). "XLV.—The Rate of Multiplication of Micro-organisms: A Mathematical Study". Proceedings of the Royal Society of Edinburgh. 31: 649–653. doi: 10.1017/S0370164600025426.
16. ^ Raymond Pearl & Lowell Reed (June 1920). "On the Rate of Growth of the Population of the United States" (PDF). Proceedings of the National Academy of Sciences of the United States of America. Vol. 6, no. 6. p. 275.
17. ^ Griffiths, Graham; Schiesser, William (2009). "Linear and nonlinear waves". Scholarpedia. 4 (7): 4308. Bibcode: 2009SchpJ...4.4308G. doi:. ISSN 1941-6016.
18. ^ Yukalov, V. I.; Yukalova, E. P.; Sornette, D. (2009). "Punctuated evolution due to delayed carrying capacity". Physica D: Nonlinear Phenomena. 238 (17): 1752–1767. arXiv:. Bibcode: 2009PhyD..238.1752Y. doi: 10.1016/j.physd.2009.05.011. S2CID 14456352.
19. ^ Gershenfeld 1999, p. 150.
20. ^ LeCun, Y.; Bottou, L.; Orr, G.; Muller, K. (1998). Orr, G.; Muller, K. (eds.). Efficient BackProp (PDF). Neural Networks: Tricks of the trade. Springer. ISBN 3-540-65311-2.
21. ^
22. ^ Villalobos-Arias, Mario (2020). "Using generalized logistics regression to forecast population infected by Covid-19". arXiv: [ q-bio.PE].
23. ^ Postnikov, Eugene B. (June 2020). "Estimation of COVID-19 dynamics "on a back-of-envelope": Does the simplest SIR model provide quantitative parameters and predictions?". Chaos, Solitons & Fractals. 135: 109841. Bibcode: 2020CSF...13509841P. doi: 10.1016/j.chaos.2020.109841. PMC . PMID 32501369.
24. ^ Saito, Takesi (June 2020). "A Logistic Curve in the SIR Model and Its Application to Deaths by COVID-19 in Japan". medRxiv. doi: 10.1101/2020.06.25.20139865. S2CID 220068969. Retrieved 20 July 2020.
25. ^ Reiser, Paul A. (2020). "Modified SIR Model Yielding a Logistic Solution". arXiv: [ q-bio.PE].
26. ^ Lee, Se Yoon; Lei, Bowen; Mallick, Bani (2020). "Estimation of COVID-19 spread curves integrating global data and borrowing information". PLOS ONE. 15 (7): e0236860. arXiv:. Bibcode: 2020PLoSO..1536860L. doi:. PMC . PMID 32726361.
27. ^ Yin, Xi; Zelenay, Piotr (13 July 2018). "Kinetic Models for the Degradation Mechanisms of PGM-Free ORR Catalysts". ECS Transactions. 85 (13): 1239–1250. doi: 10.1149/08513.1239ecst. OSTI 1471365. S2CID 103125742.
28. ^ Bod, Hay, Jennedy (eds.) 2003, pp. 147–156
29. ^ Collection of data on crop production and depth of the water table in the soil of various authors. On line: [1]
30. ^ Collection of data on crop production and soil salinity of various authors. On line: [2]
31. ^ Rocha, Leno S.; Rocha, Frederico S. A.; Souza, Thársis T. P. (5 October 2017). "Is the public sector of your country a diffusion borrower? Empirical evidence from Brazil". PLOS ONE. 12 (10): e0185257. arXiv:. Bibcode: 2017PLoSO..1285257R. doi:. ISSN 1932-6203. PMC . PMID 28981532.
32. ^ Ayres, Robert (1989). "Technological Transformations and Long Waves" (PDF). Archived from the original (PDF) on 1 March 2012. Retrieved 6 November 2010. {{ cite journal}}: Cite journal requires |journal= ( help)
33. ^ Marchetti, Cesare (1996). "Pervasive Long Waves: Is Society Cyclotymic" (PDF). Archived from the original (PDF) on 5 March 2012. {{ cite journal}}: Cite journal requires |journal= ( help)
34. ^ Marchetti, Cesare (1988). "Kondratiev Revisited-After One Cycle" (PDF). {{ cite journal}}: Cite journal requires |journal= ( help)
35. ^ Grübler, Arnulf (1990). The Rise and Fall of Infrastructures: Dynamics of Evolution and Technological Change in Transport (PDF). Heidelberg and New York: Physica-Verlag.
36. ^ Perez, Carlota (2002). . UK: Edward Elgar Publishing Limited. ISBN 1-84376-331-1. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 118, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.930052638053894, "perplexity": 8129.388676042255}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296946584.94/warc/CC-MAIN-20230326235016-20230327025016-00460.warc.gz"} |
https://quant.stackexchange.com/questions/19246/why-is-the-spot-price-not-used-as-the-forward-price-when-a-forward-contract-is-c | # Why is the spot price not used as the forward price when a forward contract is created?
If the initial value of a forward contract is zero, surely the forward price used would be the spot price at the time the contract was created?
However, my notes tell me that the forward price F, at $t = 0$ for delivery at time $t = T$, is given by $F = e^{rT}S_{0}$ where r is the risk-free rate and $S_{0}$ is the spot price at $t = 0$.
Why is this?
it's easiest to see in terms of replication. The pay-off of a forward contract is $$S_T - K.$$ We can replicate this precisely and statically by buying one unit of stock, $S_0,$ and $Ke^{-rT}$ riskless bonds growing at rate $r.$
So its value today is $$S_0 - Ke^{-rT}.$$ This has zero value if and only if $K= S_0 e^{rT}.$
This value is then called the forward price since it makes the forward contract have zero value.
• That makes a lot of sense, apart from the fact that $S_{0}$ is replicated by $Ke^{-rT}$. Could you please explain why this is? Thanks. – M Smith Aug 11 '15 at 10:47
• $S_T$ is replicated by one stock at cost $S_0$, $K$ is replicated by $Ke^{-rT}$ riskless bonds. – Mark Joshi Aug 11 '15 at 11:25
• So are all risk less bonds compounded continuously? – M Smith Aug 11 '15 at 12:23
• the argument only needs a zero coupon bond with expiry $T$, $r$ is then defined to makes its price $e^{-rT}.$ What happens between 0 and $T$ is irrelevant to the argument. – Mark Joshi Aug 11 '15 at 21:16
When you buy a forward you don't have to invest any money, so that's to your advantage in a world of positive interest rates. To charge you the same as the spot rate would be unfair, you would be "getting something for nothing", that is why the appropriate price for a forward is higher. It takes the interest rate into account, balancing things out. In equilibrium you are indifferent between a cheaper spot and a more expensive forward that frees up your money (which you can invest elsewhere).
• Forgive me for being dense, but I'm still struggling to understand how you're getting something for nothing. Surely prices have an equal chances of going up and down (in general) so someone who believed prices would fall would happily sell a forward contract at the spot price? – M Smith Aug 10 '15 at 13:48
• A forward is a derivative. Prices can go up or down, but the issuer of the derivative can completely hedge this risk, so it does not enter into the pricing. The pricing is determined by "cash and carry arbitrage", which I encourage you to look up. It is based in the spot price and the interest rate. – noob2 Aug 10 '15 at 14:04
• @user2910074 Forward is priced by static hedging. I can easily buy the asset now and hold it until the maturity. Discounted back must be the price of the forward. – SmallChess Aug 10 '15 at 14:08
The forward price $F$ for a forward contract, determined at the contract inception time today, is the price that the holder will pay at maturity $T$ to buy the underlying equity. Then the payoff, at maturity $T$, of the forward contract is given by \begin{align*} S_T-F. \end{align*} The present value of the contract is then \begin{align*} e^{-rT} \mathbb{E}\big(S_T-F\big) = S_0 - e^{-rT} F. \end{align*} As the forward price $F$ is determined so that the value of the forward contract is zero, we have \begin{align*} F= S_0 e^{rT}. \end{align*} | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6431200504302979, "perplexity": 742.7537042389584}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-47/segments/1573496668534.60/warc/CC-MAIN-20191114182304-20191114210304-00119.warc.gz"} |
https://solvedlib.com/colt-company-owns-a-machine-that-can-produce-two,58668 | # Colt Company owns a machine that can produce two specialized products Production time for Product TLX...
###### Question:
Colt Company owns a machine that can produce two specialized products Production time for Product TLX is three units per hour and for Product MTV is four units per hour. The machine's capacity is 2.400 hours per year. Both products are sold to a single customer who has agreed to buy all of the company's output up to a maximum of 4,080 units of Product TLX and 4,540 units of Product MTV Selling prices and variable costs per unit to produce the products follow Sper unit Selling price per unit Variable costs per unit Product TUX $13.5e 4.05 Product MTV$8.10 4.36 Determine the company's most profitable sales mix and the contribution margin that results from that sales mix (Round per unit contribution margins to 2 decimal places.) Product TLX Product MTV Contribution margin per unit Contribution margin per production hour Product TLX Product MTV Total 4.540 Maximum number of units to be sold Hours required to produce maximum units Product TLX Product MTV Total For Most Profitable Sales Mix Hours dedicated to the production of each product Units produced for most profitable sales mibe Contribution margin per unit Total contribution margin
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Q 10.7: Which arrow pushing diagram below represents the formation of a benzylic radical?...
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##### Yes 88 8 In the sample wete dellvered alter 10.30 AM today; this sample1
Yes 8 8 8 In the sample wete dellvered alter 10.30 AM today; this sample 1... | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 2, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7320176362991333, "perplexity": 15552.214474357212}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296946445.46/warc/CC-MAIN-20230326173112-20230326203112-00794.warc.gz"} |
https://scicomp.stackexchange.com/questions/3307/recovering-coordinates-by-eigendecomposition-without-double-centering/3311 | # Recovering coordinates by eigendecomposition without double-centering
Suppose an Euclidean distance $D\in\mathbb{R}^{n\times n}$ matrix between a set of $n$ objects is given. To obtain inner-products (which will be further be used to recover coordinates), entries of $D$ are squared, and the matrix is double-centered and scaled, ie., $K=-\frac{1}{2}JD^{(2)}J$, where matrix $J=I-\frac{1}{n}11^T$ defines the origin wrt which the inner-products are formed. So, the aim is to reconstruct coordinates $X$ that give rise to inner products $K$, $$K=-\frac{1}{2}JD^{(2)}J=JXX^TJ.$$ This is done by eigendecomposition of $K$.
Given the above equation, I wonder if one could use a shortcut $-\frac{1}{2}D^{(2)}=XX^T$, ie, obtain coordinates $X$ without double-centering $-\frac{1}{2}D^{(2)}$ (matrix $J$ is removed from the left and from the right).
Note that you can't cancel $J$ since it is singular. In general, $Ju=Jv$ implies $u=v$ if and only if $J$ has a trivial kernel, i.e., iff the rank of $J$ equals the number of columns of $J$.
• Note that I'm mainly interested in a "technical reasoning". Wouldn't a solution $X$ to i) $-\frac{1}{2}D^{(2)}=XX^T$ be also a solution to ii) $-\frac{1}{2}JD^{(2)}J=XX^T$, up to origin position. Basically, why could not one solve ii) to obtain a solution to i) (just cancel $J$ from the sides of both sides?) Note that diagonal entries would remain zero. – usero Sep 18 '12 at 13:22
• No. $X$ will usually have complex entries, and is useless. - Multiplication by $J$ on both sides makes the diagonal positive when the distance matrix is Euclidean. Note that ypu can't cancel $J$ since it is singular. – Arnold Neumaier Sep 18 '12 at 14:56
• Your last sentence answered the question and many related ones. So, in case some $J$ is invertible (general case), one could cancel it. However, suppose a system i) $C^TACx=C^Tb$ is given, for $A\in\mathbb{R}^{n\times n}$ and a rectangular $C\in\mathbb{R}^{n\times m}$, $m<n$. In what manner could one rationalize that the solution to ii) $ACx=b$ is not a solution to i) (now, $C^T$ is rectangular, hence the singularity does not apply) – usero Sep 18 '12 at 15:10
• @usero: $C^Tu=C^Tv$ implies $u=v$ if and only if $C^T$ has a trivial kernel, i.e., iff the rank of $C$ equals the number of rows. – Arnold Neumaier Sep 18 '12 at 17:32 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9318045377731323, "perplexity": 361.73636024403515}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-40/segments/1600400202686.56/warc/CC-MAIN-20200922000730-20200922030730-00797.warc.gz"} |
http://eprints.iisc.ernet.in/10449/ | # Universal conductance fluctuations and scale invariance near the metal-insulator transition
Ghosh, A and Raychaudhuri, AK (2001) Universal conductance fluctuations and scale invariance near the metal-insulator transition. In: of International APS/IEEE Conference on Noise in Physical Systems and 1/f Fluctuations, 22-25 Oct. 2001, Gainesville, FL, USA, pp. 107-110.
Full text not available from this repository. (Request a copy)
## Abstract
We present results of measurements of 1/f noise $(10^-3< f <10 Hz)$ at low temperatures (1K <T < 100 K) in Czochralski grown single crystals of Si doped with P and B with doping concentration n close to the critical composition $n_c$ of metal-insulator transition (MIT). It was shown by us before by measuring noise in a magnetic field that universal conductance fluctuation (UCF) is at the origin of the observed noise. We find that the temperature dependence of the measured noise, which increases as T is decreased, has a stronger dependence on T as the as $n\rightarrow n_c$ from above. We explained this observation within the framework of UCF theory and scaling theory of localization near the MI transition. We show that the temperature dependence of saturated UCF is significantly affected due to weakening scale dependence of conductance as the MIT is approached
Item Type: Conference Paper Copyright of this article belongs to World Scientific 1 f noise;boron;current fluctuations;electric admittance;elemental semiconductors;metal insulator transition;phosphorus;silicon Division of Physical & Mathematical Sciences > Physics 08 Aug 2007 27 Aug 2008 12:44 http://eprints.iisc.ernet.in/id/eprint/10449 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9208530783653259, "perplexity": 3306.718991862309}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-14/segments/1427131300464.72/warc/CC-MAIN-20150323172140-00267-ip-10-168-14-71.ec2.internal.warc.gz"} |
https://telescoper.wordpress.com/tag/big-bang/ | ## The Big Bang Exploded?
Posted in Biographical, The Universe and Stuff with tags , , , on October 15, 2018 by telescoper
I suspect that I’m not the only physicist who receives unsolicited correspondence from people with wacky views on Life, the Universe and Everything. Being a cosmologist, I probably get more of this stuff than those working in less speculative branches of physics. Because I’ve written a few things that appeared in the public domain, I probably even get more than most cosmologists (except the really famous ones of course).
Many “alternative” cosmologists have now discovered email, and indeed the comments box on this blog, but there are still a lot who send their ideas through regular post. Whenever I get a envelope with an address on it that has been typed by an old-fashioned typewriter it’s a dead giveaway that it’s going to be one of those. Sometimes they are just letters (typed or handwritten), but sometimes they are complete manuscripts often with wonderfully batty illustrations. I remember one called Dark Matter, The Great Pyramid and the Theory of Crystal Healing. I used to have an entire filing cabinet filled with things like his, but I took the opportunity of moving from Cardiff some time ago to throw most of them out.
One particular correspondent started writing to me after the publication of my little book, Cosmology: A Very Short Introduction. This chap sent a terse letter to me pointing out that the Big Bang theory was obviously completely wrong. The reason was obvious to anyone who understood thermodynamics. He had spent a lifetime designing high-quality refrigeration equipment and therefore knew what he was talking about (or so he said). He even sent me this booklet about his ideas, which for some reason I have neglected to send for recycling:
His point was that, according to the Big Bang theory, the Universe cools as it expands. Its current temperature is about 3 Kelvin (-270 Celsius or thereabouts) but it is now expanding and cooling. Turning the clock back gives a Universe that was hotter when it was younger. He thought this was all wrong.
The argument is false, my correspondent asserted, because the Universe – by definition – hasn’t got any surroundings and therefore isn’t expanding into anything. Since it isn’t pushing against anything it can’t do any work. The internal energy of the gas must therefore remain constant and since the internal energy of an ideal gas is only a function of its temperature, the expansion of the Universe must therefore be at a constant temperature (i.e. isothermal, rather than adiabatic). He backed up his argument with bona fide experimental results on the free expansion of gases.
I didn’t reply and filed the letter away. Another came, and I did likewise. Increasingly overcome by some form of apoplexy his letters got ruder and ruder, eventually blaming me for the decline of the British education system and demanding that I be fired from my job. Finally, he wrote to the President of the Royal Society demanding that I be “struck off” and forbidden (on grounds of incompetence) ever to teach thermodynamics in a University. The copies of the letters he sent me are still will the pamphlet.
I don’t agree with him that the Big Bang is wrong, but I’ve never had the energy to reply to his rather belligerent letters. However, I think it might be fun to turn this into a little competition, so here’s a challenge for you: provide the clearest and most succint explanation of why the temperature of the expanding Universe does fall with time, despite what my correspondent thought.
## Cosmology: The Professor’s Old Clothes
Posted in Education, The Universe and Stuff with tags , , , , , , , on January 19, 2018 by telescoper
After spending a big chunk of yesterday afternoon chatting the cosmic microwave background, yesterday evening I remembered a time when I was trying to explain some of the related concepts to an audience of undergraduate students. As a lecturer you find from time to time that various analogies come to mind that you think will help students understand the physical concepts underpinning what’s going on, and that you hope will complement the way they are developed in a more mathematical language. Sometimes these seem to work well during the lecture, but only afterwards do you find out they didn’t really serve their intended purpose. Sadly it also sometimes turns out that they can also confuse rather than enlighten…
For instance, the two key ideas behind the production of the cosmic microwave background are recombination and the consequent decoupling of matter and radiation. In the early stages of the Big Bang there was a hot plasma consisting mainly of protons and electrons in an intense radiation field. Since it was extremely hot back then the plasma was more-or-less fully ionized, which is to say that the equilibrium for the formation of neutral hydrogen atoms via
$p+e^{-} \rightarrow H+ \gamma$
lay firmly to the left hand side. The free electrons scatter radiation very efficiently via Compton scattering
$\gamma +e^{-} \rightarrow \gamma + e^{-}$
thus establishing thermal equilibrium between the matter and the radiation field. In effect, the plasma is opaque so that the radiation field acquires an accurate black-body spectrum (as observed). As long as the rate of collisions between electrons and photons remains large the radiation temperature adjusts to that of the matter and equilibrium is preserved because matter and radiation are in good thermal contact.
Image credit: James N. Imamura of University of Oregon.
Eventually, however, the temperature falls to a point at which electrons begin to bind with protons to form hydrogen atoms. When this happens the efficiency of scattering falls dramatically and as a consequence the matter and radiation temperatures are no longer coupled together, i.e. decoupling occurs; collisions can longer keep everything in thermal equilibrium. The matter in the Universe then becomes transparent, and the radiation field propagates freely as a kind of relic of the time that it was last in thermal equilibrium. We see that radiation now, heavily redshifted, as the cosmic microwave background.
So far, so good, but I’ve always thought that everyday analogies are useful to explain physics like this so I thought of the following.
When people are young and energetic, they interact very extensively with everyone around them and that process allows them to keep in touch with all the latest trends in clothing, music, books, and so on. As you get older you don’t get about so much , and may even get married (which is just like recombination, not only that it involves the joining together of previously independent entities, but also in the sense that it dramatically reduces their cross-section for interaction with the outside world). As time goes on changing trends begin to pass you buy and eventually you become a relic, surrounded by records and books you acquired in the past when you were less introverted, and wearing clothes that went out of fashion years ago.
I’ve used this analogy in the past and students generally find it quite amusing even if it has modest explanatory value. I wasn’t best pleased, however, when a few years ago I set an examination question which asked the students to explain the processes of recombination and decoupling. One answer said
Decoupling explains the state of Prof. Coles’s clothes.
Anyhow, I’m sure there’s more than one reader out there who has had a similar experience with an analogy that wasn’t perhaps as instructive as hoped or which came back to bite you. Feel free to share through the comments box…
## What the Power Spectrum misses
Posted in The Universe and Stuff with tags , , , , , , , on August 2, 2017 by telescoper
Just taking a short break from work I chatted over coffee to one of the students here at the Niels Bohr Institute about various things to do with the analysis of signals in the Fourier domain (as you do). That discussion reminded me of this rather old post (from 2009) which I thought might be worth a second airing (after a bit of editing). The discussion is all based on past cosmological data (from WMAP) rather than the most recent (from Planck), but that doesn’t change anything qualitatively. So here you are.
The picture above shows the all-sky map of fluctuations in the temperature of the cosmic microwave background across the sky as revealed by the Wilkinson Microwave Anisotropy Probe, known to its friends as WMAP.
I spent many long hours fiddling with the data coming from the WMAP experiment, partly because I’ve never quite got over the fact that such wonderful data actually exists. When I started my doctorate in 1985 the whole field of CMB analysis was so much pie in the sky, as no experiments had yet been performed with the sensitivity to reveal the structures we now see. This is because they are very faint and easily buried in noise. The fluctuations in temperature from pixel to pixel across the sky are of order one part in a hundred thousand of the mean temperature (i.e. about 30 microKelvin on a background temperature of about 3 Kelvin). That’s smoother than the surface of a billiard ball. That’s why it took such a long time to make the map shown above, and why it is such a triumphant piece of science.
I blogged a while ago about the idea that the structure we see in this map was produced by sound waves reverberating around the early Universe. The techniques cosmologists use to analyse this sound are similar to those used in branches of acoustics except that we only see things in projection on the celestial sphere which requires a bit of special consideration.
One of the things that sticks in my brain from my undergraduate years is being told that `if you don’t know what you’re doing as a physicist you should start by making a Fourier transform of everything. This approach breaks down the phenomenon being studied into a set of plane waves with different wavelengths corresponding to analysing the different tones present in a complicated sound.
It’s often very good advice to do such a decomposition for one-dimensional time series or fluctuation fields in three-dimensional Cartesian space, even you do know what you’re doing, but it doesn’t work with a sphere because plane waves don’t fit properly on a curved surface. Fortunately, however, there is a tried-and-tested alternative involving spherical harmonics rather than plane waves.
Spherical harmonics are quite complicated beasts mathematically but they have pretty similar properties to Fourier harmonics in many respects. In particular they are represented as complex numbers having real and imaginary parts or, equivalently, an amplitude and a phase (usually called the argument by mathematicians),
$Z=X+iY = R \exp(i\phi)$
This latter representation is the most useful one for CMB fluctuations because the simplest versions of inflationary theory predict that the phases φ of each of the spherical harmonic modes should be randomly distributed. What this really means is that there is no information content in their distribution so that the harmonic modes are in a state of maximum statistical disorder or entropy. This property also guarantees that the distribution of fluctuations over the sky should have a Gaussian distribution.
If you accept that the fluctuations are Gaussian then only the amplitudes of the spherical harmonic coefficients are useful. Indeed, their statistical properties can be specified entirely by the variance of these amplitudes as a function of mode frequency. This pre-eminently important function is called the power-spectrum of the fluctuations, and it is shown here for the WMAP data:
Although the units on the axes are a bit strange it doesn”t require too much imagination to interpret this in terms of a sound spectrum. There is a characteristic tone (at the position of the big peak) plus a couple of overtones (the bumps at higher frequencies). However these features are not sharp so the overall sound is not at all musical.
If the Gaussian assumption is correct then the power-spectrum contains all the useful statistical information to be gleaned from the CMB sky, which is why so much emphasis has been placed on extracting it accurately from the data.
Conversely, though, the power spectrum is completely insensitive to any information in the distribution of spherical harmonic phases. If something beyond the standard model made the Universe non-Gaussian it would affect the phases of the harmonic modes in a way that would make them non-random.
However,I will now show you how important phase information could actually be, if only we could find a good way of exploiting it. Let’s start with a map of the Earth, with the colour representing height of the surface above mean sea level:
You can see the major mountain ranges (Andes, Himalayas) quite clearly as red in this picture and note how high Antarctica is…that’s one of the reasons so much astronomy is done there.
Now, using the same colour scale we have the WMAP data again (in Galactic coordinates).
The virture of this representation of the map is that it shows how smooth the microwave sky is compared to the surface of the Earth. Note also that you can see a bit of crud in the plane of the Milky Way that serves as a reminder of the difficulty of cleaning the foregrounds out.
Clearly these two maps have completely different power spectra. The Earth is dominated by large features made from long-wavelength modes whereas the CMB sky has relatively more small-scale fuzz.
Now I’m going to play with these maps in the following rather peculiar way. First, I make a spherical harmonic transform of each of them. This gives me two sets of complex numbers, one for the Earth and one for WMAP. Following the usual fashion, I think of these as two sets of amplitudes and two sets of phases. Note that the spherical harmonic transformation preserves all the information in the sky maps, it’s just a different representation.
Now what I do is swap the amplitudes and phases for the two maps. First, I take the amplitudes of WMAP and put them with the phases for the Earth. That gives me the spherical harmonic representation of a new data set which I can reveal by doing an inverse spherical transform:
This map has exactly the same amplitudes for each mode as the WMAP data and therefore possesses an identical power spectrum to that shown above. Clearly, though, this particular CMB sky is not compatible with the standard cosmological model! Notice that all the strongly localised features such as coastlines appear by virtue of information contained in the phases but absent from the power-spectrum.
To understand this think how sharp features appear in a Fourier transform. A sharp spike at a specific location actually produces a broad spectrum of Fourier modes with different frequencies. These modes have to add in coherently at the location of the spike and cancel out everywhere else, so their phases are strongly correlated. A sea of white noise also has a flat power spectrum but has random phases. The key difference between these two configurations is not revealed by their spectra but by their phases.
Fortunately there is nothing quite as wacky as a picture of the Earth in the real data, but it makes the point that there are more things in Heaven and Earth than can be described in terms of the power spectrum!
Finally, perhaps in your mind’s eye you might consider what it might look lie to do the reverse experiment: recombine the phases of WMAP with the amplitudes of the Earth.
If the WMAP data are actually Gaussian, then this map is a sort of random-phase realisation of the Earth’s power spectrum. Alternatively you can see that it is the result of running a kind of weird low-pass filter over the WMAP fluctuations. The only striking things it reveals are (i) a big blue hole associated with foreground contamination, (ii) a suspicious excess of red in the galactic plane owing to the same problem, and (iiI) a strong North-South asymmetry arising from the presence of Antarctica.
There’s no great scientific result here, just a proof that spherical harmonic phases are potentially interesting because of the information they contain about strongly localised features
PS. These pictures were made by a former PhD student of mine, Patrick Dineen, who has since quit astrophysics to work in the financial sector for Winton Capital, which has over the years recruited a number of astronomy and cosmology graduates and also sponsors a Royal Astronomical Society prize. That shows that the skills and knowledge obtained in the seemingly obscure field of cosmological data analysis have applications elsewhere!
## A Quite Interesting Question: How Loud Was the Big Bang?
Posted in The Universe and Stuff with tags , , , , , , , on March 16, 2017 by telescoper
I just found out this morning that this blog got a mention on the QI Podcast. It’s taken a while for this news to reach me, as the item concerned is two years old! You can find this discussion here, about 16 minutes in. And no, it’s not in connection with yawning psychopaths. It was about the vexed question of how loud was the Big Bang?
I’ve posted on this before (here and here)but since I’m very busy again today I should recycle the discussion, and update it as it relates to the cosmic microwave background, which is what one of the things I work on on the rare occasions on which I get to do anything interesting.
As you probably know the Big Bang theory involves the assumption that the entire Universe – not only the matter and energy but also space-time itself – had its origins in a single event a finite time in the past and it has been expanding ever since. The earliest mathematical models of what we now call the Big Bang were derived independently by Alexander Friedman and George Lemaître in the 1920s. The term “Big Bang” was later coined by Fred Hoyle as a derogatory description of an idea he couldn’t stomach, but the phrase caught on. Strictly speaking, though, the Big Bang was a misnomer.
Friedman and Lemaître had made mathematical models of universes that obeyed the Cosmological Principle, i.e. in which the matter was distributed in a completely uniform manner throughout space. Sound consists of oscillating fluctuations in the pressure and density of the medium through which it travels. These are longitudinal “acoustic” waves that involve successive compressions and rarefactions of matter, in other words departures from the purely homogeneous state required by the Cosmological Principle. The Friedman-Lemaitre models contained no sound waves so they did not really describe a Big Bang at all, let alone how loud it was.
However, as I have blogged about before, newer versions of the Big Bang theory do contain a mechanism for generating sound waves in the early Universe and, even more importantly, these waves have now been detected and their properties measured.
The above image shows the variations in temperature of the cosmic microwave background as charted by the Planck Satellite. The average temperature of the sky is about 2.73 K but there are variations across the sky that have an rms value of about 0.08 milliKelvin. This corresponds to a fractional variation of a few parts in a hundred thousand relative to the mean temperature. It doesn’t sound like much, but this is evidence for the existence of primordial acoustic waves and therefore of a Big Bang with a genuine “Bang” to it.
A full description of what causes these temperature fluctuations would be very complicated but, roughly speaking, the variation in temperature you corresponds directly to variations in density and pressure arising from sound waves.
So how loud was it?
The waves we are dealing with have wavelengths up to about 200,000 light years and the human ear can only actually hear sound waves with wavelengths up to about 17 metres. In any case the Universe was far too hot and dense for there to have been anyone around listening to the cacophony at the time. In some sense, therefore, it wouldn’t have been loud at all because our ears can’t have heard anything.
Setting aside these rather pedantic objections – I’m never one to allow dull realism to get in the way of a good story- we can get a reasonable value for the loudness in terms of the familiar language of decibels. This defines the level of sound (L) logarithmically in terms of the rms pressure level of the sound wave Prms relative to some reference pressure level Pref
L=20 log10[Prms/Pref].
(the 20 appears because of the fact that the energy carried goes as the square of the amplitude of the wave; in terms of energy there would be a factor 10).
There is no absolute scale for loudness because this expression involves the specification of the reference pressure. We have to set this level by analogy with everyday experience. For sound waves in air this is taken to be about 20 microPascals, or about 2×10-10 times the ambient atmospheric air pressure which is about 100,000 Pa. This reference is chosen because the limit of audibility for most people corresponds to pressure variations of this order and these consequently have L=0 dB. It seems reasonable to set the reference pressure of the early Universe to be about the same fraction of the ambient pressure then, i.e.
Pref~2×10-10 Pamb.
The physics of how primordial variations in pressure translate into observed fluctuations in the CMB temperature is quite complicated, because the primordial universe consists of a plasma rather than air. Moreover, the actual sound of the Big Bang contains a mixture of wavelengths with slightly different amplitudes. In fact here is the spectrum, showing a distinctive signature that looks, at least in this representation, like a fundamental tone and a series of harmonics…
If you take into account all this structure it all gets a bit messy, but it’s quite easy to get a rough but reasonable estimate by ignoring all these complications. We simply take the rms pressure variation to be the same fraction of ambient pressure as the averaged temperature variation are compared to the average CMB temperature, i.e.
Prms~ a few ×10-5Pamb.
If we do this, scaling both pressures in logarithm in the equation in proportion to the ambient pressure, the ambient pressure cancels out in the ratio, which turns out to be a few times 10-5. With our definition of the decibel level we find that waves of this amplitude, i.e. corresponding to variations of one part in a hundred thousand of the reference level, give roughly L=100dB while part in ten thousand gives about L=120dB. The sound of the Big Bang therefore peaks at levels just a bit less than 120 dB.
As you can see in the Figure above, this is close to the threshold of pain, but it’s perhaps not as loud as you might have guessed in response to the initial question. Modern popular beat combos often play their dreadful rock music much louder than the Big Bang….
A useful yardstick is the amplitude at which the fluctuations in pressure are comparable to the mean pressure. This would give a factor of about 1010 in the logarithm and is pretty much the limit that sound waves can propagate without distortion. These would have L≈190 dB. It is estimated that the 1883 Krakatoa eruption produced a sound level of about 180 dB at a range of 100 miles. The QI podcast also mentions that blue whales make a noise that corresponds to about 188 decibels. By comparison the Big Bang was little more than a whimper..
PS. If you would like to read more about the actual sound of the Big Bang, have a look at John Cramer’s webpages. You can also download simulations of the actual sound. If you listen to them you will hear that it’s more of a “Roar” than a “Bang” because the sound waves don’t actually originate at a single well-defined event but are excited incoherently all over the Universe.
## Life as a Condition of Cosmology
Posted in The Universe and Stuff with tags , , , , , , , on November 7, 2015 by telescoper
Trigger Warnings: Bayesian Probability and the Anthropic Principle!
Once upon a time I was involved in setting up a cosmology conference in Valencia (Spain). The principal advantage of being among the organizers of such a meeting is that you get to invite yourself to give a talk and to choose the topic. On this particular occasion, I deliberately abused my privilege and put myself on the programme to talk about the “Anthropic Principle”. I doubt if there is any subject more likely to polarize a scientific audience than this. About half the participants present in the meeting stayed for my talk. The other half ran screaming from the room. Hence the trigger warnings on this post. Anyway, I noticed a tweet this morning from Jon Butterworth advertising a new blog post of his on the very same subject so I thought I’d while away a rainy November afternoon with a contribution of my own.
In case you weren’t already aware, the Anthropic Principle is the name given to a class of ideas arising from the suggestion that there is some connection between the material properties of the Universe as a whole and the presence of human life within it. The name was coined by Brandon Carter in 1974 as a corrective to the “Copernican Principle” that man does not occupy a special place in the Universe. A naïve application of this latter principle to cosmology might lead us to think that we could have evolved in any of the myriad possible Universes described by the system of Friedmann equations. The Anthropic Principle denies this, because life could not have evolved in all possible versions of the Big Bang model. There are however many different versions of this basic idea that have different logical structures and indeed different degrees of credibility. It is not really surprising to me that there is such a controversy about this particular issue, given that so few physicists and astronomers take time to study the logical structure of the subject, and this is the only way to assess the meaning and explanatory value of propositions like the Anthropic Principle. My former PhD supervisor, John Barrow (who is quoted in John Butterworth’s post) wrote the definite text on this topic together with Frank Tipler to which I refer you for more background. What I want to do here is to unpick this idea from a very specific perspective and show how it can be understood quite straightfowardly in terms of Bayesian reasoning. I’ll begin by outlining this form of inferential logic.
I’ll start with Bayes’ theorem which for three logical propositions (such as statements about the values of parameters in theory) A, B and C can be written in the form
$P(B|AC) = K^{-1}P(B|C)P(A|BC) = K^{-1} P(AB|C)$
where
$K=P(A|C).$
This is (or should be!) uncontroversial as it is simply a result of the sum and product rules for combining probabilities. Notice, however, that I’ve not restricted it to two propositions A and B as is often done, but carried throughout an extra one (C). This is to emphasize the fact that, to a Bayesian, all probabilities are conditional on something; usually, in the context of data analysis this is a background theory that furnishes the framework within which measurements are interpreted. If you say this makes everything model-dependent, then I’d agree. But every interpretation of data in terms of parameters of a model is dependent on the model. It has to be. If you think it can be otherwise then I think you’re misguided.
In the equation, P(B|C) is the probability of B being true, given that C is true . The information C need not be definitely known, but perhaps assumed for the sake of argument. The left-hand side of Bayes’ theorem denotes the probability of B given both A and C, and so on. The presence of C has not changed anything, but is just there as a reminder that it all depends on what is being assumed in the background. The equation states a theorem that can be proved to be mathematically correct so it is – or should be – uncontroversial.
To a Bayesian, the entities A, B and C are logical propositions which can only be either true or false. The entities themselves are not blurred out, but we may have insufficient information to decide which of the two possibilities is correct. In this interpretation, P(A|C) represents the degree of belief that it is consistent to hold in the truth of A given the information C. Probability is therefore a generalization of the “normal” deductive logic expressed by Boolean algebra: the value “0” is associated with a proposition which is false and “1” denotes one that is true. Probability theory extends this logic to the intermediate case where there is insufficient information to be certain about the status of the proposition.
A common objection to Bayesian probability is that it is somehow arbitrary or ill-defined. “Subjective” is the word that is often bandied about. This is only fair to the extent that different individuals may have access to different information and therefore assign different probabilities. Given different information C and C′ the probabilities P(A|C) and P(A|C′) will be different. On the other hand, the same precise rules for assigning and manipulating probabilities apply as before. Identical results should therefore be obtained whether these are applied by any person, or even a robot, so that part isn’t subjective at all.
In fact I’d go further. I think one of the great strengths of the Bayesian interpretation is precisely that it does depend on what information is assumed. This means that such information has to be stated explicitly. The essential assumptions behind a result can be – and, regrettably, often are – hidden in frequentist analyses. Being a Bayesian forces you to put all your cards on the table.
To a Bayesian, probabilities are always conditional on other assumed truths. There is no such thing as an absolute probability, hence my alteration of the form of Bayes’s theorem to represent this. A probability such as P(A) has no meaning to a Bayesian: there is always conditioning information. For example, if I blithely assign a probability of 1/6 to each face of a dice, that assignment is actually conditional on me having no information to discriminate between the appearance of the faces, and no knowledge of the rolling trajectory that would allow me to make a prediction of its eventual resting position.
In tbe Bayesian framework, probability theory becomes not a branch of experimental science but a branch of logic. Like any branch of mathematics it cannot be tested by experiment but only by the requirement that it be internally self-consistent. This brings me to what I think is one of the most important results of twentieth century mathematics, but which is unfortunately almost unknown in the scientific community. In 1946, Richard Cox derived the unique generalization of Boolean algebra under the assumption that such a logic must involve associated a single number with any logical proposition. The result he got is beautiful and anyone with any interest in science should make a point of reading his elegant argument. It turns out that the only way to construct a consistent logic of uncertainty incorporating this principle is by using the standard laws of probability. There is no other way to reason consistently in the face of uncertainty than probability theory. Accordingly, probability theory always applies when there is insufficient knowledge for deductive certainty. Probability is inductive logic.
This is not just a nice mathematical property. This kind of probability lies at the foundations of a consistent methodological framework that not only encapsulates many common-sense notions about how science works, but also puts at least some aspects of scientific reasoning on a rigorous quantitative footing. This is an important weapon that should be used more often in the battle against the creeping irrationalism one finds in society at large.
To see how the Bayesian approach provides a methodology for science, let us consider a simple example. Suppose we have a hypothesis H (some theoretical idea that we think might explain some experiment or observation). We also have access to some data D, and we also adopt some prior information I (which might be the results of other experiments and observations, or other working assumptions). What we want to know is how strongly the data D supports the hypothesis H given my background assumptions I. To keep it easy, we assume that the choice is between whether H is true or H is false. In the latter case, “not-H” or H′ (for short) is true. If our experiment is at all useful we can construct P(D|HI), the probability that the experiment would produce the data set D if both our hypothesis and the conditional information are true.
The probability P(D|HI) is called the likelihood; to construct it we need to have some knowledge of the statistical errors produced by our measurement. Using Bayes’ theorem we can “invert” this likelihood to give P(H|DI), the probability that our hypothesis is true given the data and our assumptions. The result looks just like we had in the first two equations:
$P(H|DI) = K^{-1}P(H|I)P(D|HI) .$
Now we can expand the “normalising constant” K because we know that either H or H′ must be true. Thus
$K=P(D|I)=P(H|I)P(D|HI)+P(H^{\prime}|I) P(D|H^{\prime}I)$
The P(H|DI) on the left-hand side of the first expression is called the posterior probability; the right-hand side involves P(H|I), which is called the prior probability and the likelihood P(D|HI). The principal controversy surrounding Bayesian inductive reasoning involves the prior and how to define it, which is something I’ll comment on in a future post.
The Bayesian recipe for testing a hypothesis assigns a large posterior probability to a hypothesis for which the product of the prior probability and the likelihood is large. It can be generalized to the case where we want to pick the best of a set of competing hypothesis, say H1 …. Hn. Note that this need not be the set of all possible hypotheses, just those that we have thought about. We can only choose from what is available. The hypothesis may be relatively simple, such as that some particular parameter takes the value x, or they may be composite involving many parameters and/or assumptions. For instance, the Big Bang model of our universe is a very complicated hypothesis, or in fact a combination of hypotheses joined together, involving at least a dozen parameters which can’t be predicted a priori but which have to be estimated from observations.
The required result for multiple hypotheses is pretty straightforward: the sum of the two alternatives involved in K above simply becomes a sum over all possible hypotheses, so that
$P(H_i|DI) = K^{-1}P(H_i|I)P(D|H_iI),$
and
$K=P(D|I)=\sum P(H_j|I)P(D|H_jI)$
If the hypothesis concerns the value of a parameter – in cosmology this might be, e.g., the mean density of the Universe expressed by the density parameter Ω0 – then the allowed space of possibilities is continuous. The sum in the denominator should then be replaced by an integral, but conceptually nothing changes. Our “best” hypothesis is the one that has the greatest posterior probability.
From a frequentist stance the procedure is often instead to just maximize the likelihood. According to this approach the best theory is the one that makes the data most probable. This can be the same as the most probable theory, but only if the prior probability is constant, but the probability of a model given the data is generally not the same as the probability of the data given the model. I’m amazed how many practising scientists make this error on a regular basis.
The following figure might serve to illustrate the difference between the frequentist and Bayesian approaches. In the former case, everything is done in “data space” using likelihoods, and in the other we work throughout with probabilities of hypotheses, i.e. we think in hypothesis space. I find it interesting to note that most theorists that I know who work in cosmology are Bayesians and most observers are frequentists!
As I mentioned above, it is the presence of the prior probability in the general formula that is the most controversial aspect of the Bayesian approach. The attitude of frequentists is often that this prior information is completely arbitrary or at least “model-dependent”. Being empirically-minded people, by and large, they prefer to think that measurements can be made and interpreted without reference to theory at all.
Assuming we can assign the prior probabilities in an appropriate way what emerges from the Bayesian framework is a consistent methodology for scientific progress. The scheme starts with the hardest part – theory creation. This requires human intervention, since we have no automatic procedure for dreaming up hypothesis from thin air. Once we have a set of hypotheses, we need data against which theories can be compared using their relative probabilities. The experimental testing of a theory can happen in many stages: the posterior probability obtained after one experiment can be fed in, as prior, into the next. The order of experiments does not matter. This all happens in an endless loop, as models are tested and refined by confrontation with experimental discoveries, and are forced to compete with new theoretical ideas. Often one particular theory emerges as most probable for a while, such as in particle physics where a “standard model” has been in existence for many years. But this does not make it absolutely right; it is just the best bet amongst the alternatives. Likewise, the Big Bang model does not represent the absolute truth, but is just the best available model in the face of the manifold relevant observations we now have concerning the Universe’s origin and evolution. The crucial point about this methodology is that it is inherently inductive: all the reasoning is carried out in “hypothesis space” rather than “observation space”. The primary form of logic involved is not deduction but induction. Science is all about inverse reasoning.
Now, back to the anthropic principle. The point is that we can observe that life exists in our Universe and this observation must be incorporated as conditioning information whenever we try to make inferences about cosmological models if we are to reason consistently. In other words, the existence of life is a datum that must be incorporated in the conditioning information I mentioned above.
Suppose we have a model of the Universe M that contains various parameters which can be fixed by some form of observation. Let U be the proposition that these parameters take specific values U1, U2, and so on. Anthropic arguments revolve around the existence of life, so let L be the proposition that intelligent life evolves in the Universe. Note that the word “anthropic” implies specifically human life, but many versions of the argument do not necessarily accommodate anything more complicated than a virus.
Using Bayes’ theorem we can write
$P(U|L,M)=K^{-1} P(U|M)P(L|U,M)$
The dependence of the posterior probability P(U|L,M) on the likelihood P(L|U,M) demonstrates that the values of U for which P(L|U,M) is larger correspond to larger values of P(U|L,M); K is just a normalizing constant for the purpose of this argument. Since life is observed in our Universe the model-parameters which make life more probable must be preferred to those that make it less so. To go any further we need to say something about the likelihood and the prior. Here the complexity and scope of the model makes it virtually impossible to apply in detail the symmetry principles usually exploited to define priors for physical models. On the other hand, it seems reasonable to assume that the prior is broad rather than sharply peaked; if our prior knowledge of which universes are possible were so definite then we wouldn’t really be interested in knowing what observations could tell us. If now the likelihood is sharply peaked in U then this will be projected directly into the posterior distribution.
We have to assign the likelihood using our knowledge of how galaxies, stars and planets form, how planets are distributed in orbits around stars, what conditions are needed for life to evolve, and so on. There are certainly many gaps in this knowledge. Nevertheless if any one of the steps in this chain of knowledge requires very finely-tuned parameter choices then we can marginalize over the remaining steps and still end up with a sharp peak in the remaining likelihood and so also in the posterior probability. For example, there are plausible reasons for thinking that intelligent life has to be carbon-based, and therefore evolve on a planet. It is reasonable to infer, therefore, that P(U|L,M) should prefer some values of U. This means that there is a correlation between the propositions U and L in the sense that knowledge of one should, through Bayesian reasoning, enable us to make inferences about the other.
It is very difficult to make this kind of argument rigorously quantitative, but I can illustrate how the argument works with a simplified example. Let us suppose that the relevant parameters contained in the set U include such quantities as Newton’s gravitational constant G, the charge on the electron e, and the mass of the proton m. These are usually termed fundamental constants. The argument above indicates that there might be a connection between the existence of life and the value that these constants jointly take. Moreover, there is no reason why this kind of argument should not be used to find the values of fundamental constants in advance of their measurement. The ordering of experiment and theory is merely an historical accident; the process is cyclical. An illustration of this type of logic is furnished by the case of a plant whose seeds germinate only after prolonged rain. A newly-germinated (and intelligent) specimen could either observe dampness in the soil directly, or infer it using its own knowledge coupled with the observation of its own germination. This type, used properly, can be predictive and explanatory.
This argument is just one example of a number of its type, and it has clear (but limited) explanatory power. Indeed it represents a fruitful application of Bayesian reasoning. The question is how surprised we should be that the constants of nature are observed to have their particular values? That clearly requires a probability based answer. The smaller the probability of a specific joint set of values (given our prior knowledge) then the more surprised we should be to find them. But this surprise should be bounded in some way: the values have to lie somewhere in the space of possibilities. Our argument has not explained why life exists or even why the parameters take their values but it has elucidated the connection between two propositions. In doing so it has reduced the number of unexplained phenomena from two to one. But it still takes our existence as a starting point rather than trying to explain it from first principles.
Arguments of this type have been called Weak Anthropic Principle by Brandon Carter and I do not believe there is any reason for them to be at all controversial. They are simply Bayesian arguments that treat the existence of life as an observation about the Universe that is treated in Bayes’ theorem in the same way as all other relevant data and whatever other conditioning information we have. If more scientists knew about the inductive nature of their subject, then this type of logic would not have acquired the suspicious status that it currently has.
## A Galaxy at Record Redshift?
Posted in The Universe and Stuff with tags , , , , , on July 13, 2015 by telescoper
Skimming through the arXiv this morning I discovered a paper by Zitrin et al. with the following abstract:
I’m not sure if the figures are all significant, but a redshift of z=8.68 makes this the most distant spectroscopically confirmed galaxy on record with a present proper distance of about 9.3 Gpc according to the standard cosmological model, just pipping the previous record holder (whose redshift was in any case disputed). Light from this galaxy has taken about 13.1 Gyr to reach us; that means light set out from it when the Universe was only about 4% of its current age, only about 600 million years after the Big Bang. (Those figures were obtained using the inestimable Ned Wright’s cosmology calculator.)
We are presumably seeing a very young object, in which stars are forming at a considerable rate to account for its brightness. We don’t know exactly when the first stars formed and began to ionize the intergalactic medium, but every time the cosmic distance record is broken we push that time back closer to the Big Bang.
Mind you, I can’t say I’m overwhelmingly convinced by the identification of the redshifted Lyman-α line:
But what do I know? I’m a theorist whose suspicious of data. Any observers care to comment?
## Why the Big Bang wasn’t as loud as you think…
Posted in The Universe and Stuff with tags , , , , , on March 31, 2015 by telescoper
So how loud was the Big Bang?
I’ve posted on this before but a comment posted today reminded me that perhaps I should recycle it and update it as it relates to the cosmic microwave background, which is what I work on on the rare occasions on which I get to do anything interesting.
As you probably know the Big Bang theory involves the assumption that the entire Universe – not only the matter and energy but also space-time itself – had its origins in a single event a finite time in the past and it has been expanding ever since. The earliest mathematical models of what we now call the Big Bang were derived independently by Alexander Friedman and George Lemaître in the 1920s. The term “Big Bang” was later coined by Fred Hoyle as a derogatory description of an idea he couldn’t stomach, but the phrase caught on. Strictly speaking, though, the Big Bang was a misnomer.
Friedman and Lemaître had made mathematical models of universes that obeyed the Cosmological Principle, i.e. in which the matter was distributed in a completely uniform manner throughout space. Sound consists of oscillating fluctuations in the pressure and density of the medium through which it travels. These are longitudinal “acoustic” waves that involve successive compressions and rarefactions of matter, in other words departures from the purely homogeneous state required by the Cosmological Principle. The Friedman-Lemaitre models contained no sound waves so they did not really describe a Big Bang at all, let alone how loud it was.
However, as I have blogged about before, newer versions of the Big Bang theory do contain a mechanism for generating sound waves in the early Universe and, even more importantly, these waves have now been detected and their properties measured.
The above image shows the variations in temperature of the cosmic microwave background as charted by the Planck Satellite. The average temperature of the sky is about 2.73 K but there are variations across the sky that have an rms value of about 0.08 milliKelvin. This corresponds to a fractional variation of a few parts in a hundred thousand relative to the mean temperature. It doesn’t sound like much, but this is evidence for the existence of primordial acoustic waves and therefore of a Big Bang with a genuine “Bang” to it.
A full description of what causes these temperature fluctuations would be very complicated but, roughly speaking, the variation in temperature you corresponds directly to variations in density and pressure arising from sound waves.
So how loud was it?
The waves we are dealing with have wavelengths up to about 200,000 light years and the human ear can only actually hear sound waves with wavelengths up to about 17 metres. In any case the Universe was far too hot and dense for there to have been anyone around listening to the cacophony at the time. In some sense, therefore, it wouldn’t have been loud at all because our ears can’t have heard anything.
Setting aside these rather pedantic objections – I’m never one to allow dull realism to get in the way of a good story- we can get a reasonable value for the loudness in terms of the familiar language of decibels. This defines the level of sound (L) logarithmically in terms of the rms pressure level of the sound wave Prms relative to some reference pressure level Pref
L=20 log10[Prms/Pref].
(the 20 appears because of the fact that the energy carried goes as the square of the amplitude of the wave; in terms of energy there would be a factor 10).
There is no absolute scale for loudness because this expression involves the specification of the reference pressure. We have to set this level by analogy with everyday experience. For sound waves in air this is taken to be about 20 microPascals, or about 2×10-10 times the ambient atmospheric air pressure which is about 100,000 Pa. This reference is chosen because the limit of audibility for most people corresponds to pressure variations of this order and these consequently have L=0 dB. It seems reasonable to set the reference pressure of the early Universe to be about the same fraction of the ambient pressure then, i.e.
Pref~2×10-10 Pamb.
The physics of how primordial variations in pressure translate into observed fluctuations in the CMB temperature is quite complicated, because the primordial universe consists of a plasma rather than air. Moreover, the actual sound of the Big Bang contains a mixture of wavelengths with slightly different amplitudes. In fact here is the spectrum, showing a distinctive signature that looks, at least in this representation, like a fundamental tone and a series of harmonics…
If you take into account all this structure it all gets a bit messy, but it’s quite easy to get a rough but reasonable estimate by ignoring all these complications. We simply take the rms pressure variation to be the same fraction of ambient pressure as the averaged temperature variation are compared to the average CMB temperature, i.e.
Prms~ a few ×10-5Pamb.
If we do this, scaling both pressures in logarithm in the equation in proportion to the ambient pressure, the ambient pressure cancels out in the ratio, which turns out to be a few times 10-5. With our definition of the decibel level we find that waves of this amplitude, i.e. corresponding to variations of one part in a hundred thousand of the reference level, give roughly L=100dB while part in ten thousand gives about L=120dB. The sound of the Big Bang therefore peaks at levels just a bit less than 120 dB.
As you can see in the Figure above, this is close to the threshold of pain, but it’s perhaps not as loud as you might have guessed in response to the initial question. Modern popular beat combos often play their dreadful rock music much louder than the Big Bang….
A useful yardstick is the amplitude at which the fluctuations in pressure are comparable to the mean pressure. This would give a factor of about 1010 in the logarithm and is pretty much the limit that sound waves can propagate without distortion. These would have L≈190 dB. It is estimated that the 1883 Krakatoa eruption produced a sound level of about 180 dB at a range of 100 miles. By comparison the Big Bang was little more than a whimper.
PS. If you would like to read more about the actual sound of the Big Bang, have a look at John Cramer’s webpages. You can also download simulations of the actual sound. If you listen to them you will hear that it’s more of a “Roar” than a “Bang” because the sound waves don’t actually originate at a single well-defined event but are excited incoherently all over the Universe. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 10, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.792308509349823, "perplexity": 486.692762073503}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-47/segments/1573496668561.61/warc/CC-MAIN-20191115015509-20191115043509-00476.warc.gz"} |
http://mathoverflow.net/questions/53537/what-is-an-example-of-a-finite-centerless-group-with-at-least-3-generators/53577 | What is an example of a finite centerless group with at least 3 generators?
I need one to test a theory. There are probably many, but I can't seem to think of a single one. My guess is examples are pretty big.
Is there a systematic way to find such examples? Are there databases one can go through to find these things?
-
Are you thinking of finite groups? – Yemon Choi Jan 27 '11 at 21:13
Finite. I'll change it. – Makhalan Duff Jan 27 '11 at 21:15
Can't you take products of simple groups? – José Figueroa-O'Farrill Jan 27 '11 at 21:19
A direct product of simple groups can be 2-generated. – Mark Sapir Jan 27 '11 at 21:38
A direct product of enough copies of a given FSG is not 2-generated. – Jonathan Kiehlmann Jan 27 '11 at 21:48
The group $S_3\wr ({\mathbb Z}_2 \times {\mathbb Z}_2 \times {\mathbb Z}_2)$ where $S_3$ is the symmetric group with 6 elements, ${\mathbb Z}_2$ is the group with 2 elements, $\wr$ is the wreath product.
The fact that it does not have a center is proved by inspection. The fact that it needs at least 3 generators follows from the fact that ${\mathbb Z}_2^3$ is its quotient. There are lots of similar examples of course.
Update. In general , if you take any centerless group $G$ and any group $H$ that needs at least 3 generators, then the wreath product $G\wr H$ has both properties (is centerless and needs at least 3 generators). Another way to construct examples is (as Derek Holt comment below shows) to take any centerless finite group $G$ with nontrivial abelianization and take $G\times G\times G$.
-
Isn't that written $S_3\wreath\mathbb Z_2$? – Mariano Suárez-Alvarez Jan 27 '11 at 21:29
$A\wr B$ is the semidirect product of $A^B$ and $B$ where $B$ acts on the direct power $A^B$ by permuting components of vectors. There is a competing notation for the same thing $B\wr A$ used by some dynamics people. But the original (I think due Kaluzhnin and Krasner) is as above. Note that ${\mathbb Z} \wr S_3$ has a center, consisting of constant vectors in the base, also it is not that trivial to show that this wreath product needs 3 generators. – Mark Sapir Jan 27 '11 at 21:35
Why not just $S_3^3$ ? – Derek Holt Jan 27 '11 at 22:54
@Mariano: Yes, $3!=6$. – Mark Sapir Jan 27 '11 at 23:42
@Mariano: Your computation is absolutely correct. – Mark Sapir Jan 28 '11 at 0:50
The smallest example has order 18. It has a normal elementary abelian subgroup $N$ of order 9, and an element $t$ of order 2 such that $txt=x^{-1}$ for all $x \in N$.
-
More generally, an extension of an elementary abelian 3-group $N$ of order $3^r$ by an element of order 2 that inverts everything in $N$ is the smallest example of a centreless group that needs $r+1$ generators. – Derek Holt Jan 28 '11 at 9:15
I can't prove this, but the Rubik's cube group might work.
Update: so this doesn't work. Thanks for the comments.
-
Why do you think so? In any case, gap tells me that the center is cyclic of order $2$ (I'm using the generators from gap-system.org/Doc/Examples/rubik.html) – Mariano Suárez-Alvarez Jan 28 '11 at 8:41
The non trivial central permutation is the one which flips the middle cube of each side. Cute. – Mariano Suárez-Alvarez Jan 28 '11 at 8:45
A quick calculation in GAP or Magma also shows that this group is 2-generated. – Derek Holt Jan 28 '11 at 9:13
@Derek, how did you check? I tried GQuotients(FreeGroup(2), G : findall := false) with G is the cube group module its center (which is centerless) but it seems to take forever---I am pretty sure there are faster ways to do this? – Mariano Suárez-Alvarez Jan 28 '11 at 9:17
@Mariano: gap> G = Subgroup(G, [Random(G), Random(G)] ); true The probability of this returning true seems to be about 0.55. – Derek Holt Jan 28 '11 at 12:07 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8568861484527588, "perplexity": 475.800531536865}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-14/segments/1427131309986.40/warc/CC-MAIN-20150323172149-00276-ip-10-168-14-71.ec2.internal.warc.gz"} |
http://mathhelpforum.com/advanced-math-topics/154374-multivariable-functions.html | 1. ## multivariable functions
COncerning finding the domain of functions in two variables, I'm unsure as to how to sketch the graph of an equation with two square roots. i have sketched the graph of the domain of each of the terms simple enough for this function:
f(x,y)= (sqrt(4-x^2-y^2)) - (sqrt(1-x^2))
i end up with a circle for the first term and a parabola for the second. when i sketch the graph of the domain of the entire function, should i get the intersection? or just put one sketch on top of the other? please help. thank you
2. Let me see. To be exact, the domain of the first term is all $(x,y)$ such that
$4-x^{2}-y^{2}\ge 0$, which implies
$4\ge x^{2}+y^{2}.$ So that's all the points $(x,y)$ inside or on the boundary of the circle of radius 2 centered at the origin.
The domain of the second term is all $(x,y)$ such that
$1-x^{2}\ge 0,$ which implies $x^{2}-1\le 0,$ or $(x-1)(x+1)\le 0.$
There are three regions involved here: $(-\infty,-1), (-1,1), (1,\infty).$ You also have the boundary points $\pm 1,$ which are clearly in the domain, since equality is allowed. If you plug in numbers, you can see that it is only the $x$ values in $[-1,1]$ that are allowed. $y$ doesn't matter in this second piece.
So, finally, to answer your question: you must take the intersection of these two regions, because if you go outside either of them, one part of your function will not be defined (if you're assuming you have real functions, which I am assuming).
Does this make sense?
3. Thanks for your reply. And i believe that does make sense. thanks very much. although im quite confused about the boundaries of the circle. would it not be the sqaure root of 2? instead of 2. although the radius would be two. anyway, i think i got the important bit which is to just take the intersection then.
Highly appreciate your help. More questions to come.
4. No, if you've got the equation $x^{2}+y^{2}=4,$ that is the equation of a circle of radius 2. To see this, suppose $x=0.$ What $y$ values satisfy the equation? Well, the equation is now $0+y^{2}=4,$ implying that $y^{2}=4$, or $y=\pm 2.$ So two points on the circle are $(0,2)$ and $0,-2).$ The distance away from the origin for both points is 2. Hence the radius is 2.
You're very welcome for whatever help I could provide. Have a good one! | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 21, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.934206485748291, "perplexity": 138.5831360339036}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-09/segments/1518891816178.71/warc/CC-MAIN-20180225070925-20180225090925-00455.warc.gz"} |
https://s18612.gridserver.com/1yvcll/seurat-boxplot-instead-of-violin-plot-e488cc | Individual outliers are not visible in a violin plot. features: Features to plot (gene expression, metrics, PC scores, anything that can be retreived by FetchData) cols: Colors to use for plotting. Let us load Pandas, Seaborn and Matplotlib. batches. Thanks for contributing an answer to Bioinformatics Stack Exchange! Stack Exchange network consists of 176 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. In this post we will see how to show mean mark on boxplot using Seaborn in Python. Along which margins to show the plots. Seurat object. To demonstrate how a violin plot is different from a box plot, compare the following two representations: In this case, we see the limitation of the violin plot for small sample sizes (hint: the limitation is not that the plot does not seem to show violins but vases). Building a violin plot with ggplot2 is pretty straightforward thanks to the dedicated geom_violin() function. Nice article! pt.size. Since it relies on density estimation, the plot only makes sense if a sufficient number of data are available for obtaining reliable estimates. It plots violins instead of boxplots. The R ggplot2 boxplot is useful for graphically visualizing the numeric data group by specific data. Seurat object. idents: Which classes to include in the plot (default is all) sort Please correct the marked field(s) below. A violin plot is a compact display of a continuous distribution. However, the combine argument is currently broken in VlnPlot. The idea of a violin plot is to combine a box plot with a density plot. This happens because the violin plots are combined using cowplot::plot_grid before being returned by VlnPlot. There are a couple ways to graph a boxplot through Python. margins. There are, however, also plots that provide a bit of additional information. I have links to my pictures and Seurat object too. It shows the distribution of quantitative data across several levels of one (or more) categorical variables such that those distributions can be compared. We will use the warpbreaks data set to exemplify the use of the plot. The shape represents the density estimate of the variable: the more data points in a specific range, the larger the violin is for that range. pt.size: Point size for geom_violin. It may be easier to estimate relative differences in density plots, though I don’t know of any research on the topic. © 2020 Data Science Blog: Understand. I am trying to create violin plots with boxplots within each violin plot. Luckily, geom_boxplot() has the argument width, which scales the width of the boxplot (e.g. Violin plot allows to visualize the distribution of a numeric variable for one or several groups. This R tutorial describes how to create a violin plot using R software and ggplot2 package.. violin plots are similar to box plots, except that they also show the kernel probability density of the data at different values.Typically, violin plots will include a marker for the median of the data and a box indicating the interquartile range, as in standard box plots. You can graph a boxplot through seaborn, matplotlib, or pandas. However, I would like to graph a violin plot, but have the fill shade correspond to the 3 quartiles of my data. The “violin” shape of a violin plot comes from the data’s density plot. I have a very simple dataset (2 groups, n=15 per group). Each ‘violin’ represents a group or a variable. I am a beginner to commuting by bike and I find it very tiring. idents. In this example, we show how to add a boxplot to R Violin Plot using geom_boxplot function. To further facilitate the comparison, summary statistics (mean, median, boxplot, violinplot) and inferential statistics (confidence intervals) can be added. Bioinformatics Stack Exchange is a question and answer site for researchers, developers, students, teachers, and end users interested in bioinformatics. Hello everyone, I am struggling to change the order of my clusters in the graphs using seurat v3.0. smooth.lines: prints a smooth line curve. As a rule of thumb, the more curvaceous the density plot appears, especially in/around the interquartile range (i.e. But this will simply lead into an empty box on top of my plots: This happens because the violin plots are combined using cowplot::plot_grid before being returned by VlnPlot. vioplot(pbmc_small@dr@pca[,1]~pbmc_small@meta.data\$, Separate boxplots for multiple violin plot, https://github.com/TomKellyGenetics/vioplot, FeaturePlot from Seurat: change its title. A guide to creating modern data visualizations with R. Starting with data preparation, topics include how to create effective univariate, bivariate, and multivariate graphs. A violin plot shows the distribution’s density using the width of the plot, which is symmetric about its axis, while traditional density plots use height from a common baseline. We include a command ‘cheat sheet’, a brief introduction to new commands, data accessors, visualization, and multiple assays in Seurat v3.0; The command ‘cheat sheet’ also contains a translation guide between Seurat v2 and v3 About Seurat. Although I've been able to create the violin plot on its own, I am not sure how to create the boxplot. You can prevent the plots from being combined by setting combine=FALSE, then modify each one by adding a boxplot, then combine the modified plots using Seurat::CombinePlots. A boxplot isn't that complicated. The summary plot (Potter et al., 2010) is a similar idea. Use MathJax to format equations. It combines a minimal boxplot with glyphs rep-resenting the first five moments (mean, standard deviation, skewness, kurtosis and tailings), and a sectioned density plot crossed with a violin plot (both colour and width are … So, when should you use a beeswarm plot? Only applies if type = "violin". He is currently driving the digitization of the German railway system at DB Systel. Making statements based on opinion; back them up with references or personal experience. On the /r/sam… Seurat is an R package designed for QC, analysis, and exploration of single-cell RNA-seq data. Integer describing the relative size of the marginal plots compared to the main plot. Here is an example showing how people perceive probability. In this post, I am trying to make a stacked violin plot in Seurat. In addition, change the points to have shape = 95 which is a horizontal tick mark. Thanks for the help! emph.dots Ceramic resonator changes and maintains frequency when touched, Deep Reinforcement Learning for General Purpose Optimization. I would for there to be a boxplot for each of the fill groups at each of the x variables. The violin plot. TIP: Please refer R ggplot2 Boxplot article to understand the Boxplot arguments. 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Platform -- how do I add a colour annotation bar to the 3 quartiles my. Advisors know example showing how people perceive probability example, we show how to add a colour annotation to. Inside unencrypted MSSQL Server backup file ( *.bak ) without SSMS the relative size of the two groups two. Straightforward thanks to the box plot that is, instead of a continuous distribution data. Continuous distribution plot only makes sense if a sufficient number of data are available for obtaining estimates... For right reasons ) people make inappropriate racial remarks which scales the width similar. Data with line plots, though I seurat boxplot instead of violin plot ’ t know of any research on the a!
Essick Moist Air Humidifier Manual, Watch Shackleton's Antarctic Adventure, Glow In The Dark Hair Dye For Dark Hair, Whole House Water Filter Cartridge For Well Water, Resume For Preschool Teacher Fresher, Famous Honolulu Beach Area Codycross, Magnavox 32mf301b/f7 Remote, Roasted Broccoli And Kale Salad, Acrylic Round Towel Bar Replacement, Ggplot Histogram Breaks, Fry Bread Recipe With Milk, Touch Power Switch, | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.25429922342300415, "perplexity": 2916.1325347495676}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-31/segments/1627046154897.82/warc/CC-MAIN-20210804174229-20210804204229-00602.warc.gz"} |
https://www.math3ma.com/blog/stone-weierstrass-theorem | # Stone Weierstrass Theorem
Let $X$ be a topological space and let $C(X,\mathbb{R})$ denote the set of all continous functions $f:X\to\mathbb{R}$.
A family $\mathscr{F}$ of functions is an algebra if for every $f,g\in\mathscr{F}$ and any $c\in \mathbb{R}$, we have $f+g,fg, cf\in\mathscr{F}$.
• ex: $C([a,b],\mathbb{R})$ is an algebra for any closed interval $[a,b]\subset\mathbb{R}$.
An algbera $\mathscr{A}$ of functions $f:X\to \mathbb{R}$ separates points if for every $x,y\in X$ there is a function $f\in \mathscr{A}$ such that $f(x)\neq f(y)$.
• ex: Let $\mathscr{P}\subset C([a,b],\mathbb{R})$ denote the set of polynomials on $[a,b]$. Then $\mathscr{P}$ is a subalgebra which separates points since it contains the polynomial $f(x)=x$.
An algbera $\mathscr{A}$ of functions $f:X\to \mathbb{R}$ vanishes nowhere if for every $x\in X$ there is a function $f\in\mathscr{A}$ such that $f(x)\neq 0$.
• ex: Let $\mathscr{P}\subset C([a,b], \mathbb{R})$ denote the set of polynomials on $[a,b]$. Then $\mathscr{P}$ is a subalgebra that separates points since it contains the polynomial $f(x)=x$.
These definitions come together in today's theorem:
In English, this just says that any continuous, real-valued function on a compact set can be approximated (with respect to the supremum norm) by some function in your algebra $\mathscr{A}$. In other words, choose any continuous function $f:X\to \mathbb{R}$ where $X$ is compact. Then for every $\epsilon >0$, we can find a function $g\in \mathscr{A}$ such that $$\|f-g\|=\sup_{x\in X}\{|f(x)-g(x)|\}<\epsilon.$$ Here's an example: take $X=[a,b]$ to be a closed interval in $\mathbb{R}$ and let $\mathscr{A}$ be the set of all polynomials on $[a,b]$. Then for any continuous $f:[a,b]\to\mathbb{R}$ and any $\epsilon>0$, we can find a polynomial $p:[a,b]\to\mathbb{R}$ such that $\|f-p\|< \epsilon$. This is the familar Weierstrass Approximation Theorem! Any continous function on a closed interval can be approximated - as close as you want - by a polynomial. The Stone Weierstrass Theorem says that this result is still true if we replace $[a,b]$ by any compact set $X$, and if we replace the set of polynomials by any subalgebra of $C(X,\mathbb{R})$ which separates points and vanishes nowhere.
Now you might ask, "Why do we need $X$ to be compact?" and "Why must $\mathscr{A}$ separate points and vanish nowhere?" Today we'll see why these hypotheses are necessary. Next time we'll work through an exercise from Rudin's Principal of Mathematical Analysis (a.k.a. "Baby Rudin") to see the theorem in action.
## Why do we need compactness?
The best way to answer this question is to look at a counterexample. So let's consider $X=\mathbb{R}$ and let $\mathscr{A}$ be the subalgebra of all poynomials on $\mathbb{R}$. Then $\mathscr{A}$ separates points and vanishes nowhere, but $X$ is not compact. In this case, the theorem fails since the function $f(x)=e^x$ cannot be approximated by any polynomial! This is because any polynomial $p$ is dominated by its largest term, say $x^n$, and $e^x$ tends to $\infty$ much faster than does $x^n$ (even if $n$ is very large). As a result, the distance between $e^x$ and $x^n$ cannot be made arbitrarily small as $x$ ranges over all of $\mathbb{R}$.
But if we restrict ourselves to a closed and bounded interval, the smaller terms in $p$ have more weight, and this allows us to approximate $e^x$ by $p(x)$ with as much accuracy as we want. And this is exactly what we've all done in undergraduate calculus! You remember those problems. The $n$th degree Taylor polynomial of $e^x$ centered at 0 is $$e^x\approx \sum_{k=0}^n\frac{x^k}{k!},$$ and a typical homework question might've been something like, "For what values of $x$ is this approximation accurate to within 0.00001?". The answer would be $|x|<\delta$ for some constant $\delta$ which you could find using Taylor's Inequality. This $[-\delta,\delta]$ is precisely the compact set we need to restrict to in order to obtain a good approximation.
## Why must the algebra separate points?
Again we'll consider a counterexample. This time let $X=[a,b]\subset\mathbb{R}$ and take $\mathscr{A}$ to be the collection of all polynomials $p:[a,b]\to\mathbb{R}$ such that $p(a)=p(b)$. It's easy to check that this forms an algebra, and it clearly does not separate points. To see where the Stone Weierstrass Theorem fails, simply choose any continuous function $f:[a,b]\to\mathbb{R}$ such that $f(a),f(b)\neq p(a),p(b)$. Then we cannot approximate $f$ by any polynomial $p\in\mathscr{A}$ because we can always find an $\epsilon$ such that $\|f-p\|\geq \epsilon.$ In fact, $\epsilon=|f(b)-f(a)|/2$ does the job.
This isn't too hard to show. Let $M=\max\{|f(a)-p(a)|,|f(b)-p(b)|\}$ and observe from the picture above that $\|f-p\|\geq M$. We want to show* $$\|f-p\|\geq M\geq \frac{|f(b)-f(a)|}{2}.$$ To see this, let $m$ denote the common value $p(a)=p(b)$, assume WLOG $f(a)\leq f(b)$, and suppose $f(a)< m < f(b)$. If, for instance, $m=|f(a)+f(b)|/2$, then $M=|f(a)+f(b)|/2$ and the claim is true.
Otherwise, if, say, $m$ lies in-between $|f(a)+f(b)|/2$ and $f(b)$ (see insert on the left), then $M=|f(a)-m|$ which is greater than $|f(a)-f(b)|/2$ as claimed. And if $m< f(a)$ or $m>f(b)$, then $M$ is even larger and again the claim holds.
Alternatively we could also choose $\mathscr{A}$ to be the set of constant functions on $[a,b]$ (this definitley does not separate points). Then, for example, the function $f(x)=e^x$ can't be approximated by any constant $c$ since $\|e^x-c\|$ is bounded below by $\frac{|e^b-e^a|}{2}$ (using the same argument as above).
## Why must the algebra vanish nowhere?
Suppose $X=[0,1]$ and let's take $\mathscr{A}$ to be the set of all continuous functions $p:[0,1]\to\mathbb{R}$ such that $p(0)=0$ (one easily checks that this is an algebra). Then any continuous function $f$ which is not zero at zero can't be approximated by any $p\in\mathscr{A}$! The supremum of $|f(x)-p(x)|$ for $x$ in $[0,1]$ is bounded below by $|f(0)-p(0)|=|f(0)|.$ For instance take $f(x)=x+3$. Then $\|f-p\|$ is at least 3.
So there you go! Each of the conditions in the Stone Weierstrass Theorem is indeed necessary. Next week we'll use the theorem to solve this exercise from Baby Rudin:
• (Rudin, PMA #7.20) If $f$ is continuous on $[0,1]$ and if $\int_0^1f(x)x^n\;dx=0$ for all $n=0,1,2,\ldots,$ prove that $f(x)=0$ on $[0,1]$.
Footnote:
* We don't want to let $M=\max\{|f(a)-p(a)|,|f(b)-p(b)|\}$ be our $\epsilon$ since we need $\epsilon$ to be independent of the polynomial $p$. (The negation of the Stone-Weierstrass Theorem says that if $X$ is not compact or if $\mathscr{A}$ is an algebra which does not separate points or does not vanish nowhere, then there exists a function $f\in C(X,\mathbb{R})$ and there exists $\epsilon>0$ such that $\|f-p\|\geq \epsilon$ for all $p\in\mathscr{A}$. The wording implies that $\epsilon$ depends on $f$ only.)
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Related Posts | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9837870597839355, "perplexity": 77.99512492308273}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-43/segments/1570986649035.4/warc/CC-MAIN-20191014025508-20191014052508-00134.warc.gz"} |
https://appliedphysicsusa.com/one-step-closer-to-deeper-explorations-into-space-improved-performance-of-plasma-thrusters/ | A researcher at Tohoku University has made significant improvements to a high-power electrodeless plasma thruster, bringing us closer to deeper space exploration.
The magnetic nozzle rf plasma thruster operated in a Mega hpt vacuum chamber at Tohoku University. Credit: Kazunori Takahashi
These advancements in electric propulsion technology have the potential to revolutionize the space industry in the same way that innovations in terrestrial transportation, such as cars, trains, and aircraft, have transformed their respective industries.
Electric propulsion is a technique utilizing electromagnetic fields to accelerate a propellant and generate thrust that propels a spacecraft. Space agencies have pioneered electric propulsion technology as the future of space exploration.
Already, several space missions have successfully been completed using electric propulsion devices, such as gridded ion thrusters and Hall thrusters. Solar power is converted into thrust energy when the propellant becomes ionized, i.e., a plasma, and gets accelerated by electromagnetic fields. Yet, the electrodes necessary for these devices limit their lifetime, since they get exposed to and damaged by the plasma, especially at a high-power level.
To circumvent this, scientists have turned to electrodeless plasma thrusters. One such technology harnesses radio frequency (rf) to generate plasma. An antenna emits radio waves into a cylindrical chamber to create plasma, where a magnetic nozzle channels and accelerates the plasma to generate thrust. MN rf plasma thrusters, or helicon thrusters as they are sometimes known, offer simplicity, operational flexibility, and a potentially high thrust-to-power ratio.
But the development of MN rf plasma thrusters has been stymied by the conversion efficiency of the rf power to thrust energy. Early experiments generated single-digit conversion rates, but more recent studies have reached a modest outcome of 20%.
In a recent study, Professor Kazunori Takahashi, from Tohoku University’s Department of Electrical Engineering, has achieved a 30% conversion efficiency.
Whilst mature electric propulsion devices often use xenon gas, which is expensive and difficult to supply in sufficient quantities, the current 30% efficiency was obtained with argon propellant. This indicates that an MN rf plasma thruster would reduce the cost and the resource load from the Earth.
“Applying a cusp-type magnetic field inhibited the energy loss that generally occurs to the plasma source wall,” Takahashi said. “The breakthrough opens the door to advances in high-power space transportation technology.”
Reference: “Thirty percent conversion efficiency from radiofrequency power to thrust energy in a magnetic nozzle plasma thruster” by Kazunori Takahashi, 10 November 2022, Scientific Reports.
DOI: 10.1038/s41598-022-22789-7 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8258265256881714, "perplexity": 4836.186598714149}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764499829.29/warc/CC-MAIN-20230130201044-20230130231044-00063.warc.gz"} |
https://www.physicsforums.com/threads/if-g-o-f-ida-and-f-o-g-idb-then-g-f-1-proof.591281/ | # Homework Help: If g o f = idA and f o g = idB, then g = f^-1 proof?
1. Mar 28, 2012
### Norm850
Hey guys,
I need to prove: Suppose A and B are sets, and f and g are functions with f: A -> B and g: B -> A. If g o f = idA and f o g = idB, then f is invertible and g = f^-1.
So far I have understood why g must be the inverse of f, but I do not know how to prove it.
Thanks!
2. Mar 28, 2012
### tazzzdo
Take an arbitrary element a in A and b in B and show that they relate via composition of both functions.
3. Mar 28, 2012
### tazzzdo
Hint: f(a) = b, g(b) = a
4. Mar 28, 2012
### Norm850
Okay, not really sure how to do that but here's my attempt:
Suppose g o f = idA,
then dom(g o f) = dom(idA) = A
and (g o f)(a) = g(f(a)) = idA(a) = a.
Suppose f o g = idB,
then dom(f o g) = dom(idB) = B
and (f o g)(b) = f(g(b)) = idB(b) = b.
5. Mar 28, 2012
### tazzzdo
A function is only invertible if it's 1 - 1 and onto. Is this the case? You didn't specify.
6. Mar 28, 2012
### Norm850
So what I have is sufficient for g=f^-1? But first I need to show that f^-1 exists?
7. Mar 28, 2012 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8200297355651855, "perplexity": 1714.7317785763316}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-39/segments/1537267162809.73/warc/CC-MAIN-20180926002255-20180926022655-00295.warc.gz"} |
http://mathcentral.uregina.ca/QQ/database/QQ.09.09/h/neven2.html | SEARCH HOME
Math Central Quandaries & Queries
Question from Neven: The cone of smallest possible volume is circumscribed about a given hemisphere. What is the ratio of its height to the diameter of its base? (G.F.Simmons, Calculus with Analytic Geometry, CH4 Applications of Derivatives)
Neven,
I assume that your cone is a right circular cone. In other words, a cross section containing the axis is an isosceles triangle with its incircle. Assume that the radius of the sphere (and therefore of the incircle) is 1. Let x be the distance from the vertex of the cone to the centre of the sphere, t be the length of a tangent line from the vertex, and r be the radius of the base of the cylinder.
Using similar triangles and Pythagoras theorem write the volume of the cone as a function of x. Use calculus to find the value of x that minimizes the volume of the cone and the ratio you want is (x + 1)/(2r).
Chris
Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9556458592414856, "perplexity": 174.3515979662212}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-18/segments/1461861812410.28/warc/CC-MAIN-20160428164332-00130-ip-10-239-7-51.ec2.internal.warc.gz"} |
http://mathhelpforum.com/new-users/205039-simplifying-laws-logarithms-print.html | # Simplifying with laws of logarithms
• October 10th 2012, 11:45 AM
Scottrich12
Simplifying with laws of logarithms
I am currently studying engineering level 3 NVQ and have been having problems with logarithms, the problems I have been given I don't understand these are:
Use laws of logarithms methods to simplify and evaluate the equation given:
Simplify 5n = 7 x 2n, rearrange and make n the subject
also another problem is
Simplify θ = 250 x e-0.05 x t and make t the subject
and continuing from that:
what is the value of t when θ = 195C
• October 10th 2012, 11:57 AM
TheEmptySet
Re: Simplifying with laws of logarithms
Quote:
Originally Posted by Scottrich12
I am currently studying engineering level 3 NVQ and have been having problems with logarithms, the problems I have been given I don't understand these are:
Use laws of logarithms methods to simplify and evaluate the equation given:
Simplify 5n = 7 x 2n, rearrange and make n the subject
also another problem is
Simplify θ = 250 x e-0.05 x t and make t the subject
and continuing from that:
what is the value of t when θ = 195C
For problem number one there are many ways to solve it. Here is one
$5^n=7 \cdot 2^n \iff \frac{5^n}{2^n}=7$
$\left( \frac{5}{2}\right)^n=7$
Now if we take the natural logarithm of both sides we get
$\ln\left( \frac{5}{2}\right)^n=\ln(7) \iff n\ln\left( \frac{5}{2}\right)=\ln(7)$
Solving for n gives
$n=\frac{\ln(7) }{\ln\left( \frac{5}{2}\right)}$
Now you try the 2nd one and remember that $\ln( e^{t})=t$
• October 10th 2012, 12:37 PM
Scottrich12
Re: Simplifying with laws of logarithms
How would this be written as log to the base 10?
• October 10th 2012, 02:20 PM
skeeter
Re: Simplifying with laws of logarithms
Quote:
Originally Posted by Scottrich12
How would this be written as log to the base 10?
you've posted this problem twice ...
http://mathhelpforum.com/algebra/205...thms-help.html
... in future, please refrain from double posting. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 5, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8406122922897339, "perplexity": 1638.1938770915556}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-36/segments/1471982293922.13/warc/CC-MAIN-20160823195813-00086-ip-10-153-172-175.ec2.internal.warc.gz"} |
https://www.hpmuseum.org/forum/showthread.php?mode=linear&tid=1901&pid=16837 | Four LIF text conversion questions
08-01-2014, 05:04 PM
Post: #1
Joe Horn Senior Member Posts: 1,849 Joined: Dec 2013
Four LIF text conversion questions
Four separate questions seeking separate answers, in one thread because they are similar.
(Q1) Ordinary text files on LIF systems are hex type 0001, and are referred to as LIF1 files. Converting them to MS-DOS text is easy, e.g. with the HPDir program. But the HP-75 has its own text files of hex type E052. I can't figure out any way with just an HP-71 (no 75), PIL-Box, and 9114 disk drive, to convert those HP-75 text files to MS-DOS text files. Is it possible?
(Q2) Many LIF1 files on the Swap Disks have embedded "Text Editor" commands, such as ^CE (for Center Mode), ^MA (for setting the left and right margins), etc. Has anybody written any kind of program for converting these formatting commands into modern notation of any kind, like PostScript or TeX or whatever, so that these files could be presented for example as RTF's or PDF's with all the authors' formatting intact?
(Q3) There are many LIF1 files on the Swap Disks which contain only graphic data (100% escape codes and bitmap data), no text. These were intended to be sent directly to the ThinkJet printer, which interpreted the escape codes correctly and output the desired image. Has anybody written a program of any kind that converts these files into modern image files, e.g. PNG or BMP or whatever? I've tried a few PCL-to-PNG converters without any success.
(Q4) Similar to the previous two items, many LIF1 files on the Swap Disks contain ThinkJet-specific printer codes, such as CHR$(14) to turn on Bold Mode and CHR$(15) to turn it off again. These are neither Text Editor commands, nor standard PCL codes. Has anybody written any kind of program for converting these files to modern marked-up text?
Thanks in advance for any help you can offer! I'm converting all of the LIF1 files I can find into web-presentable form, and doing these conversions by hand is tedious.
<0|ɸ|0>
-Joe-
08-01-2014, 06:48 PM
Post: #2
Tony Duell Junior Member Posts: 38 Joined: Dec 2013
RE: Four LIF text conversion questions
For Q1, my LIF utilities for Linux, available from the HPCC web site :
http://www.hpcc.org/datafile/hpil/lif_utils.html
(or ask me if you can't find them) include a program to decode HP75 text files into
plain ASCII. Although written for linux, it shouldn't be too hard to translate to another OS, and the C source should be a start.
08-02-2014, 07:56 AM
Post: #3
Joe Horn Senior Member Posts: 1,849 Joined: Dec 2013
RE: Four LIF text conversion questions
Thanks, Tony! No success yet at compiling your utilities for DOS. Has anybody ever succeeded at that? Google comes up empty.
<0|ɸ|0>
-Joe-
08-02-2014, 10:58 AM
Post: #4
Marcus von Cube Senior Member Posts: 760 Joined: Dec 2013
RE: Four LIF text conversion questions
(08-02-2014 07:56 AM)Joe Horn Wrote: Thanks, Tony! No success yet at compiling your utilities for DOS. Has anybody ever succeeded at that? Google comes up empty.
Joe, why do you want to target DOS instead of, say, Win32?
Marcus von Cube
Wehrheim, Germany
http://www.mvcsys.de
http://wp34s.sf.net
http://mvcsys.de/doc/basic-compare.html
08-02-2014, 12:10 PM
Post: #5
Sylvain Cote Senior Member Posts: 1,784 Joined: Dec 2013
RE: Four LIF text conversion questions
(08-02-2014 07:56 AM)Joe Horn Wrote: Thanks, Tony! No success yet at compiling your utilities for DOS. Has anybody ever succeeded at that? Google comes up empty.
If you use the command line on Windows you should install a POSIX layer and it then should be easier to compile or port linux code.
There are several available but CygWin (http://www.cygwin.com) is the one used more often and the breath of packages available for it is impressive.
08-02-2014, 12:21 PM
Post: #6
Joe Horn Senior Member Posts: 1,849 Joined: Dec 2013
RE: Four LIF text conversion questions
(08-02-2014 10:58 AM)Marcus von Cube Wrote:
(08-02-2014 07:56 AM)Joe Horn Wrote: Thanks, Tony! No success yet at compiling your utilities for DOS. Has anybody ever succeeded at that? Google comes up empty.
Joe, why do you want to target DOS instead of, say, Win32?
Tony's utilities are command-line (aka "terminal") programs, so compiling them for a DOS window (cmd.exe) on my 32-bit Win7 computer is my only option, I think.
<0|ɸ|0>
-Joe-
08-02-2014, 11:47 PM
Post: #7
Dave Frederickson Senior Member Posts: 2,120 Joined: Dec 2013
RE: Four LIF text conversion questions
(08-01-2014 05:04 PM)Joe Horn Wrote: (Q1) Ordinary text files on LIF systems are hex type 0001, and are referred to as LIF1 files. Converting them to MS-DOS text is easy, e.g. with the HPDir program. But the HP-75 has its own text files of hex type E052. I can't figure out any way with just an HP-71 (no 75), PIL-Box, and 9114 disk drive, to convert those HP-75 text files to MS-DOS text files. Is it possible?
If you had access to an HP-75 you could TRANSFORM those files into LIF1 format, then HPDir could convert them to DOS text.
Dave
08-03-2014, 08:50 AM
Post: #8
Joe Horn Senior Member Posts: 1,849 Joined: Dec 2013
RE: Four LIF text conversion questions
(08-02-2014 11:47 PM)Dave Frederickson Wrote: If you had access to an HP-75 you could TRANSFORM those files into LIF1 format, then HPDir could convert them to DOS text.
Hey, Dave, that gives me an idea: It would be easy to write an HP-71 program that reads the file's data directly from the disk (using IL commands, sector by sector), reconstructs the lines (optionally discarding the line numbers) and writes it all out to an ordinary LIF1 file. Essentially an HP-75 TRANSFORM using an HP-71. Amazing that nobody's done that before (?). Ok, that's Sunday's programming challenge to myself....
<0|ɸ|0>
-Joe-
08-03-2014, 12:49 PM
Post: #9
Marcus von Cube Senior Member Posts: 760 Joined: Dec 2013
RE: Four LIF text conversion questions
(08-02-2014 12:21 PM)Joe Horn Wrote:
(08-02-2014 10:58 AM)Marcus von Cube Wrote: Joe, why do you want to target DOS instead of, say, Win32?
Tony's utilities are command-line (aka "terminal") programs, so compiling them for a DOS window (cmd.exe) on my 32-bit Win7 computer is my only option, I think.
Ah, I do understand now. People keep thinking of the Windows command line as a variant of DOS which it definitely isn't. DOS is a 16 bit single tasking environment, while the Windows command line, starting with Windows NT, offers the full Windows API. (As an aside, You can even start a GUI program from a command window, as you probably already know). The problem with porting command line utilities targeted at Unix environments is that these tend to deviate from the POSIX standard and directly call Unix specific APIs like "open" instead of "fopen" or depend on the existence of certain external utilities or file system locations. Toolboxes like CygWin fill this gap.
Marcus von Cube
Wehrheim, Germany
http://www.mvcsys.de
http://wp34s.sf.net
http://mvcsys.de/doc/basic-compare.html
08-04-2014, 03:23 AM
Post: #10
Joe Horn Senior Member Posts: 1,849 Joined: Dec 2013
RE: Four LIF text conversion questions
A1. Well, THAT was fun! I just finished getting an HP-71 program running which converts HP-75 text files on disk (type E052) into standard text files (LIF1, type 0001). Why on earth does EVERY line of an HP-75 text file begin (after the 2-byte line number and 1-byte line length) with a space character?!? What a waste. But the program works. So Q1 is handled to my satisfaction. Now to convert all the HP-75 text files on all the swap disks so that anybody with Internet access can read them.
Q2 and Q4 (embedded formatting codes) should be easy to translate into HTML with a macro in a text editor or MS Word.
Q3 (converting ThinkJet graphics to image files) looks hopeless.
<0|ɸ|0>
-Joe-
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https://cs.stackexchange.com/questions/53726/nth-number-in-a-infinite-sequence-of-numbers | # Nth number in a infinite sequence of numbers
This was interview question.
When the input is a infinite sequence of numbers starting from 1, what is the nth digit?
e.g.) 123456789101112131415161718192021.....
here 28th digit is 1.
• What have you tried? Where did you get stuck? What are you looking for in an answer? Are you looking for an algorithm? Note that coding questions are off-topic here. If you're looking for an algorithm, what approaches did you consider? – D.W. Feb 29 '16 at 7:05
• You'll find a lot of references on OEIS. – Gilles 'SO- stop being evil' Mar 11 '16 at 21:29
(defun nth-digit (n)
(loop :with previous := 0
:for i :upfrom 0
:sum (* 9 (expt 10 i) (1+ i)) :into digits
:if (> digits n) :do
(multiple-value-bind (whole remainder)
(floor (- n previous) (1+ i))
(return (aref (write-to-string (+ (expt 10 i) whole)) remainder)))
:else :do (setf previous digits)))
The idea for implementation is to:
1. Sum the length of all 1-digit numbers (of which there are $9*10^0$), then sum all 2-digit numbers (of which there are $9*10^1$), 3-digit numbers, of which there are $9*10^2$ and so on. This gives:
$$N = \sum_{i=0}^m 9\times 10^i \times (i+1)$$
1. Notice that $x = \lfloor\frac{n - N}{i+1}\rfloor$ will be a positive integer which counts the number of numbers having $m+1$ digits in them.
2. Finally, after you've already found what number contains your digit, you can find $e$ s.t. $r - e = 10^i + \frac{n - N}{i+1}$, and $e \leq i$ the $e'th$ digit of $x$ is going to be the one you are looking for.
• Probably, i + 1 instead of i in step 1? – Sungguk Lim Feb 29 '16 at 4:05
• @SunggukLim yup, it should be i +1. – wvxvw Feb 29 '16 at 6:44
The idea here is as follows:
• The first 9 digits are 123456789.
• The next 90 pairs of digits are (10)(11)...(99).
• The following 900 triplets of digits are (100)(101)...(999).
• And so on.
Given an index $n$, you calculate which group you are (singles, pairs, triplets, ...), then which tuple you belong to and which digit inside the tuple. For example, if $n=28$ then this is digit no. 19 in the second group, which is the first digit of the 10th tuple 19, that is, 1. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5693621635437012, "perplexity": 1329.3637133778598}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-05/segments/1579250614086.44/warc/CC-MAIN-20200123221108-20200124010108-00485.warc.gz"} |
https://www.dummies.com/article/academics-the-arts/study-skills-test-prep/armed-services/asvab-mathematics-knowledge-practice-circles-242204/ | ##### ASVAB AFQT
If you love circles—and who doesn't!—then you're in for a treat when you take the Mathematics Knowledge subtest on the ASVAB. Of course, enthusiasm isn't enough; you should also know the formulas for the circumference and area of a circle, and also how to switch a formula around to get the right answer.
## Practice questions
1. Based on this diagram,
2. Based on this diagram,
find the circumference of the circle.
1. The correct answer is Choice (B).
The formula for the area of a circle is
2. The correct answer is Choice (C).
First, notice that the answer choices are in terms of pi. That means you won't have to multiply by 3.14.
The formula to find the circumference of a circle is
Because you know the diameter is 210 feet, the radius is 105 feet. Use what you know in the formula:
You can solve the problem more quickly using an alternate formula for the circumference,
where d is the diameter. Mentally insert d = 210 in for d, and you get | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8998815417289734, "perplexity": 690.9063950849677}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764499790.41/warc/CC-MAIN-20230130003215-20230130033215-00872.warc.gz"} |
https://gitlab.math.tu-dresden.de/backofen/amdis/-/commit/0adfa8e7eb7dc8e1c952120c3bc766ce83e1518f | ### And even more work....
parent 0a79fc7f
... ... @@ -85,17 +85,18 @@ namespace AMDiS { #if HAVE_PARALLEL_DOMAIN_AMDIS Element *otherEl = NULL; int otherEdge = -1; FixRefinementPatch::getOtherEl(stack, &otherEl, otherEdge); vector refineEdges; FixRefinementPatch::getOtherEl(stack, refineEdges); // === If the refinement edge must be fixed, add also the other part of this === // === edge to the refinement patch. === if (otherEl) { if (refineEdges.size()) { // TODO: Remove these two lines and make something more meaningful!! el->setMark(0); return; Element *otherEl = refineEdges[0].first; TraverseStack stack2; ElInfo *elInfo2 = ... ...
... ... @@ -46,31 +46,25 @@ namespace AMDiS { /// Implements \ref CoarseningManager::coarsenFunction void coarsenFunction(ElInfo *el_info); /** \brief * Coarsens a single Tetrahedron of the coarsening patch. DOFs * in the interior of the element are removed; DOFs for higher order * at the boundary or the coarsening patch still belong to * the parent. Do not remove them form the mesh!!! */ /// Coarsens a single Tetrahedron of the coarsening patch. DOFs /// in the interior of the element are removed; DOFs for higher order /// at the boundary or the coarsening patch still belong to /// the parent. Do not remove them form the mesh!!! void coarsenTetrahedron(RCNeighbourList &coarsenList, int index); /** \brief * Gets the patch for coarsening starting on element * el_info->el in direction of neighbour [3-dir]; returns 1 if a boundary * reached and 0 if we come back to the starting element. * We complete the loop also in the case of a incompatible * coarsening patch since then all marks of patch elements are reset by * coarsenPatch() and this minimizes calls of traverseNeighbour(); * if we reach a boundary while looping around the edge we loop back to * the starting element before we return */ /// Gets the patch for coarsening starting on element /// el_info->el in direction of neighbour [3-dir]; returns 1 if a boundary /// reached and 0 if we come back to the starting element. /// We complete the loop also in the case of a incompatible /// coarsening patch since then all marks of patch elements are reset by /// coarsenPatch() and this minimizes calls of traverseNeighbour(); /// if we reach a boundary while looping around the edge we loop back to /// the starting element before we return bool getCoarsenPatch(ElInfo* el_info, DegreeOfFreedom *edge[2], int dir, RCNeighbourList &coarsenList, int *n_neigh); /** \brief * First rebuild the DOFs on the parents then do restriction * of data (if possible) and finally coarsen the patch elements */ /// First rebuild the DOFs on the parents then do restriction /// of data (if possible) and finally coarsen the patch elements void coarsenPatch(RCNeighbourList &coarsenList, int n_neigh, int bound); }; ... ...
... ... @@ -253,8 +253,10 @@ namespace AMDiS { } } #ifndef HAVE_PARALLEL_DOMAIN_AMDIS if (!solver) WARNING("no solver created\n"); #endif // === create estimator === if (initFlag.isSet(INIT_ESTIMATOR)) ... ...
... ... @@ -655,9 +655,14 @@ namespace AMDiS { #ifdef HAVE_PARALLEL_DOMAIN_AMDIS Element *otherEl = NULL; int otherEdge = -1; FixRefinementPatch::getOtherEl(stack, &otherEl, otherEdge); vector refineEdges; FixRefinementPatch::getOtherEl(stack, refineEdges); if (refineEdges.size()) { MSG("FIX REFINEMENT PATH ON ELEMENT %d %d: %d additional edges\n", elInfo->getElement()->getIndex(), elInfo->getMacroElement()->getIndex(), refineEdges.size()); } #endif // === Traverse and refine the refinement patch. ==== ... ... @@ -669,10 +674,20 @@ namespace AMDiS { } #ifdef HAVE_PARALLEL_DOMAIN_AMDIS // === If the refinement edge must be fixed, add also the other part of this === // === edge to the refinement patch. === // === If the refinement edge must be fixed, add also the other part === // === of this edge to the refinement patch. === for (int edgeIndex = 0; edgeIndex < static_cast(refineEdges.size()); edgeIndex++) { MSG(" IN REF FIX: %d %d\n", refineEdges[edgeIndex].first->getIndex(), refineEdges[edgeIndex].second); } for (int edgeIndex = 0; edgeIndex < static_cast(refineEdges.size()); edgeIndex++) { if (otherEl) { MSG(" MAKE -> %d\n", edgeIndex); Element *otherEl = refineEdges[edgeIndex].first; TraverseStack stack2; ElInfo *elInfo2 = stack2.traverseFirstOneMacro(mesh, otherEl->getIndex(), -1, ... ... @@ -811,15 +826,14 @@ namespace AMDiS { void FixRefinementPatch::getOtherEl(TraverseStack *stack, Element **otherEl, int &otherEdge) vector& refineEdges) { FUNCNAME("FixRefinementPatch::getOtherEl()"); if (!FixRefinementPatch::connectedEdges.empty()) { // === Get stack of current traverse. === std::vector elInfos; std::vector infos; vector elInfos; vector infos; int stackUsed = stack->getStackData(elInfos, infos); int checkIndex = stackUsed; int localEdgeNo = 0; ... ... @@ -849,28 +863,26 @@ namespace AMDiS { checkIndex--; } // If the refinement edge is part of an edge on the macro level, we must // check if the refinement edge is part of an edge that must be fixed. if (localEdgeNo >= 0) { int macroElIndex = elInfos[checkIndex]->getElement()->getIndex(); TEST_EXIT_DBG(elInfos[checkIndex]->getLevel() == 0) ("Should not happen!\n"); TEST_EXIT_DBG(elInfos[checkIndex]->getElement()->getIndex() == elInfo->getMacroElement()->getIndex()) TEST_EXIT_DBG(macroElIndex == elInfo->getMacroElement()->getIndex()) ("Should not happen!\n"); TEST_EXIT_DBG(localEdgeNo <= 5)("Should not happen!\n"); for (unsigned int i = 0; i < FixRefinementPatch::connectedEdges.size(); i++) { if (FixRefinementPatch::connectedEdges[i].first.first->getIndex() == elInfos[checkIndex]->getElement()->getIndex() && FixRefinementPatch::connectedEdges[i].first.second == localEdgeNo) { // Okay, we have found that this edge must be fixed. *otherEl = FixRefinementPatch::connectedEdges[i].second.first; otherEdge = FixRefinementPatch::connectedEdges[i].second.second; break; refineEdges.clear(); for (int i = 0; i < static_cast(connectedEdges.size()); i++) { if (connectedEdges[i].first.first->getIndex() == macroElIndex && connectedEdges[i].first.second == localEdgeNo) { // We have found that this edge must be fixed. refineEdges.push_back(connectedEdges[i].second); } } } ... ...
... ... @@ -86,7 +86,8 @@ namespace AMDiS { static ConnectedEdges connectedEdges; static void getOtherEl(TraverseStack *stack, Element **otherEl, int &otherEdge); static void getOtherEl(TraverseStack *stack, vector &refineEdges); }; } ... ... | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9068006873130798, "perplexity": 18617.437274242522}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323585183.47/warc/CC-MAIN-20211017210244-20211018000244-00637.warc.gz"} |
https://www.lessonplanet.com/teachers/fractions-lesson-1-4th-5th | # Fractions Lesson 1
In this math worksheet, students solve the various problems that are related to fractions. The skills of using the different operations is used. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8778336048126221, "perplexity": 1853.5633136385898}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-43/segments/1508187822992.27/warc/CC-MAIN-20171018142658-20171018162658-00104.warc.gz"} |
https://ora.ox.ac.uk/objects/uuid:f899f218-db88-4d94-ade5-5bd29736490e | Conference
### TIME-RESOLVED RAMAN MEASUREMENT OF INTERVALLEY SCATTERING IN GASB
Abstract:
Time-resolved Raman spectroscopy with subpicosecond resolution has been used to measure L- Gamma intervalley scattering of photoexcited electrons in GaSb. Our experiment measures directly the time-dependent occupancy of non-equilibrium longitudinal optic phonons with wavevector approximately 10 6 cm -1 which are generated by intra- Gamma relaxation of electrons near the Gamma minimum. The phonon population shows a two-component decay: at times
Publication status:
Published
### Access Document
Publisher copy:
10.1088/0268-1242/9/5S/086
### Authors
Volume:
9
Issue:
5
Pages:
719-721
Publication date:
1994-05-05
DOI:
EISSN:
1361-6641
ISSN:
0268-1242
URN:
Source identifiers:
27814
Local pid:
pubs:27814
Keywords: | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9025896787643433, "perplexity": 22872.997393391033}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-31/segments/1627046151641.83/warc/CC-MAIN-20210725080735-20210725110735-00375.warc.gz"} |
http://math.stackexchange.com/questions/222767/convergence-of-a-sequence?answertab=oldest | # Convergence of a sequence
I have to prove the following statement:
Let $(X_n)_{n\in\mathbb{N}}$ be a sequence of real numbers, such that $\exp(itX_n)$ converges for every $t\in\mathbb{R}$. Show that the sequence $(X_n)$ converges.
The problem I see is, that the complex logarithm is not continous. Hence, I have to work around, but I dont know how. I hope someone can help.
-
## migrated from stats.stackexchange.comOct 28 '12 at 14:56
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Hint: if $\exp(itX_n)$ converges to $z$, then $z\ne 0$ and $\exp(itX_n)/z$ converges to $1$. Now you can take logarithms (at least for $n$ sufficiently large) because the complex logarithm is continuous in a neighborhood of $1$. – whuber Oct 28 '12 at 14:59
why should $z\neq0$ hold? that is not obvious for me... – johanMozart Oct 28 '12 at 15:10
I am thinking about a prove along following lines: (i) show that the limit of $\exp(itX_n)$ is of the form $\exp(itX_\infty)$ (ii) show that $\exp(itX_n)$ is continous for all t. then it should be possible to conclude that $(X_n)$ converges too. But (i) seems to be difficult to show (at least for me). – johanMozart Oct 28 '12 at 15:15
for me, as a non-mathematician, this seems to be standard. can't noone help? :) – johanMozart Oct 28 '12 at 16:33
Observe that if convergence of $\exp(i t X_n)$ is only postulated for $t\in\mathbb Q$, the sequence $(X_n)$ may indeed diverge. – Hagen von Eitzen Oct 28 '12 at 21:26
Since I've been chewing on this for a while now, allow me to first construct a divergent sequence $(X_n)_{n\in\mathbb N}$ such that $(e^{itX_n})_{n\in\mathbb N}$ is convergent for all $t\in\mathbb Q$, before I shall solve the original problem below.
## Counterexample for $\mathbb Q$ (incomplete space)
Let $(q_n)_{n\in\mathbb N}$ be an enumeration of $\mathbb Q\setminus 0$. Observe that $\bigcap_{k=1}^n q_k\mathbb Z=r_n\mathbb Z$ for some $r_n\in \mathbb Q_{>0}$. By letting $y_1=0$, and selecting $y_n\in r_n\mathbb Q$ with $y_n>y_{n-1}+1$ we obtain a diverging sequence $(y_n)_{n\in\mathbb N}$. If $t\in\mathbb Q$, then $ty_n\in\mathbb Z$ for almost all $n$: If $t=0$, this is trivial; if $t\ne 0$, we find $N$ with $\frac1t=q_N$ and have $y_n\in q_N\mathbb Z$ for all $n\ge N$.
Therefore, by letting $X_n=2\pi y_n$ we find a divergent sequence $(X_n)_{n\in\mathbb N}$ such that $(e^{itX_n})_{n\in\mathbb N}$ is convergent (in fact, is eventually constant $=1$) for all $t\in \mathbb Q$.
## Proof for the case $\mathbb R$ (complete space)
What's different with $\mathbb R$ instead of $\mathbb Q$? First let's see that $(X_n)_{n\in\mathbb N}$ is bounded: For $c>0$ and $N\in\mathbb N$ consider the set $$A_{c,N}=\{t\in\mathbb R\mid\forall n,m\ge N\colon t(X_n-X_m)\in[-c,c]+2\pi\mathbb Z\}.$$ If $t\notin A_{c,N}$, then there are $n,m\ge N$, $k\in\mathbb Z$ with $2k\pi+c<t(X_n-X_m)<2(k+1)\pi-c$, which also holds for $t'$ if
$$|t'-t|<\frac{\min\{t(X_n-X_m)-2k\pi-c,2(k+1)\pi-c-t(X_n-X_m)\}}{|X_n-X_m|}.$$ Therefore the complements of the $A_{c,N}$ are open and the $A_{c,N}$ themselves are closed. The convergence of $(e^{itX_n})_{n\in\mathbb N}$ for all $t\in\mathbb R$ implies that for any $c>0$ we have $$\mathbb R=\bigcup_{N\in\mathbb N}A_{c,N}$$ Specifically, we can consider $c=\frac{2\pi}5$. By the Baire category theorem, there exists an $N$ such that $A_{c,N}$ contains an open interval $(t_0-\epsilon,t_0+\epsilon)$ with $\epsilon>0$. Without loss of generality, $t_0\ne0$ and $\epsilon< |t_0|$. Let $$M=\max\left\{|X_1|,\ldots,|X_N|\right\}+\frac\pi{\epsilon}.$$ Then $(X_n)_{n\in\mathbb N}$ is bounded by $M$. To prove this, assume that $|X_n|>M$ for some $n$. Then clearly $n>N$ and $|X_n-X_N|>\frac\pi{\epsilon}$. Because $n>N$, there exists $k\in\mathbb Z$ such that $|t_0(X_n-X_N)-2k\pi|\le c$. Let $t_1=t_0+\frac\pi{(X_n-X_N)}$ so that $|t_1-t_0|<\epsilon$ and hence $t_1\in A_{c,N}$. Then there is $k'\in\mathbb Z$ with $|t_1(X_n-X_N)-2k'\pi|\le c$. But $|t_1(X_n-X_N)-t_0(X_n-X_N)|=\pi$ makes this impossible because $2c<\pi<2\pi-2c$: the left inequality rules out $k=k'$, the other rules out $|k-k'|\ge 1$. We conclude that $(X_n)_{n\in\mathbb N}$ is bounded.
Now the final step is easy: If $|X_n|\le M$ for all $n$, then consider the case $0<t<\frac\pi{2M}$. For such $t$, all $tX_n$ are in $(-\frac\pi2,\frac\pi2)$. Since the map $(-\frac\pi2,\frac\pi2)\to \mathbb C$, $x\mapsto e^{ix}$ is an embedding, convergence of $(e^{itX_n})_{n\in\mathbb N}$ implies convergence of $(tX_n)_{n\in\mathbb N}$ and finally convergence of $(X_n)_{n\in\mathbb N}$.$_\blacksquare$
-
Hi Hagen, yes this is what I had in my mind, but which I was not able to perform correctly!!! Thank you! – johanMozart Oct 30 '12 at 19:27
For the counterexample, $X_n=2\pi (n!)$ without enumeration of $\mathbb Q$. – Did Nov 8 '12 at 11:28
Here's a solution that takes advantage of a little Fourier analysis.
Set $y_n = \int_{-\infty}^\infty e^{-t^2/2} e^{i t x_n}\,dt$. Since $|e^{i t x_n}| = 1$ and $e^{-t^2/2}$ is integrable, the dominated convergence theorem implies that $y_n$ converges to some finite value $y$. On the other hand, computing the integral above shows that $y_n = \frac{1}{\sqrt{2 \pi}} e^{-x_n^2/2}$. (This is the fact that a Gaussian is its own Fourier transform.) If we define $f : [0,\infty) \to \mathbb{R}$ by $f(x) = \frac{1}{\sqrt{2 \pi}} e^{-x^2/2}$, we have $y_n = f(|x_n|)$. Now $f$ is continuous and strictly decreasing, so it has a continuous inverse. Hence $|x_n| = f^{-1}(y_n) \to f^{-1}(y)$. Call this limit $x$.
If $x=0$ then we have $x_n \to 0$. Otherwise, let $s_n$ be the sign of $x_n$ and consider $z_n := \sin(\frac{\pi}{2} \frac{x_n}{x})$. On the one hand $z_n$ is the imaginary part of $e^{i \pi x_n / 2x}$ and hence $z_n$ converges to some $z$. On the other hand, since $\sin$ is an odd function we have $$s_n = \frac{z_n}{\sin(\frac{\pi}{2} \frac{|x_n|}{x})}.$$ Since $|x_n| \to x$, the denominator converges to 1, and so $s_n$ converges to some $s = \pm 1$. Thus $x_n = s_n |x_n| \to s x$.
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Hi Nate... I am not sure if I understand correctly your approach. However, I am missing something in your solution: You nowhere used that $\exp(itx_n)$ converges. We have to show that $x_n$ converges, if the sequence of the complex exponentials converges. The crucial point here is the existence of a limit of the form $\lim_{n\rightarrow\infty}\exp(itx_n)=\exp(itx_\infty)$, where the $x_\infty$ does not depend on $t$. However, I have a sketch of the prove in my mind, which I described above... – johanMozart Oct 30 '12 at 19:22
I used the fact that $\exp(itx_n)$ converges when I invoked the dominated convergence theorem; its hypothesis is that the integrands converge pointwise. I didn't assume anything about what the limit function looks like. – Nate Eldredge Oct 31 '12 at 0:23
Actually, we don't need to require the converge of $\{e^{itx_n}\}$ for each $t$ in the real line, but only for $t\in A$, where $A$ is of positive Lebesgue measure.Let $l(t):=\lim_{n \to +\infty}e^{itx_n}$ for $t\in A$.
• We show that $\{x_n\}$ is bounded. Suppose not. By the dominated convergence theorem, for all $A'\subset A$, $\int_{A'}e^{itx_n}dt\to \int_{A'}l(t)dt$. But it also converges to $0$ by Riemann-Lebesgue lemma. We deduce that $l=0$ on $A'$, a contradiction.
• Assume that for a subsequences of $\{x_n\}$, say $\{x_{n'}\}$ and $\{x_{n''}\}$ converge respectively to $x'$ and $x''$. We have to show that $x'=x''$. We have by dominated converge theorem that $\int_{A'}e^{itx'}dt=\int_{A'}e^{itx''}dt$ for all $A'\subset A$ measurable. This gives that $e^{itx'}=e^{itx''}$ for all $t\in A$. If $x'\neq x''$, then defining $S:=\frac 1{x'-x''}A$, we would have $e^{is}=1$ for $s$ is a set of positive Lebesgue measure, a contradiction, as $S$ should contain points which are not of the form $2k\pi$, $k\in\Bbb Z$.
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https://dsp.stackexchange.com/questions/72110/unclear-point-about-quantization | ## Quantization of Continuous-Amplitude Signals
This point is not clear to me:
"The smallest quantization levels ($$\pm\Delta$$) correspond to the least significant bit of the binary code word."
• i retitled the graphic because the previous title was completely wrong. – robert bristow-johnson Dec 21 '20 at 19:08
Quantization is a process of representing real values of a signal using integer numbers. That process results in loss of accuracy, which is determined by the selection of the smallest value of quantization level.
If the smallest quantization level is $$\Delta$$, then every signal level will be rounded to the multiple of that $$\Delta$$. For example, if a signal level is $$x=3,3 V$$ and $$\Delta = 1V$$, then the corresponding quantized representation of the signal level will be $$Q(x)=3\Delta$$ and the resulting $$\hat x = 3_{10} = 11_2$$. If $$\Delta = 0.5V$$, then the signal level will be $$Q(x)=7\Delta$$ and the resulting $$\hat x = 7_{10} = 111_2$$.
So, to rephrase the original point: the weight of the least significant bit of the binary code word equals $$\Delta$$.
• This is not correct for negative signal values and moreover the binary number format is two's complement which is different from base 2. – DSPinfinity Dec 21 '20 at 20:40
• This answer is still correct for negative values/2s-compliment. All they are saying is ‘this is how we encode the output of the quantizer in binary’. – Dan Szabo Dec 21 '20 at 21:20
• @DSPinfinity To add to what Dan Szabo said, a note regarding negative numbers and different codes: if x is a signed binary, then two's complement code is obtained with this expression: 2^N - x, and offset binary code is obtained with this: x + 2^(N-1). So the code just adds a constant and doesn't change the weight of LSB. – megasplash Dec 22 '20 at 10:33
That is well-said. Here, $$x_Q$$ is a multiple of $$\Delta$$. A value $$x$$ can be writen as $$x_Q+e_Q$$, with remainder $$|e_Q|<\Delta$$. The last significant bit will be either 0 or 1, depending on the location of $$|e_Q|$$ with respect to $$\Delta/2$$: if $$|e_Q|<\Delta/2$$, the last bit is $$0$$, else it is $$1$$.
There is not finer quantization level.
• your explanation was harder to understand. – DSPinfinity Dec 20 '20 at 23:35
• I'll try again tomorrow, not on my phone – Laurent Duval Dec 20 '20 at 23:36
• thank you Laurent. – DSPinfinity Dec 20 '20 at 23:37
• Meanwhile, do not hesitate to add what you {partly} understood so far – Laurent Duval Dec 20 '20 at 23:42
• For example, for $\Delta$, the corresponding code is 001 for which the least significant bit is 1. For $3\Delta$, the corresponding code is 011 for which again the least significant bit is 1. – DSPinfinity Dec 20 '20 at 23:58 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 21, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6054663062095642, "perplexity": 461.350292876147}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-10/segments/1614178362481.49/warc/CC-MAIN-20210301090526-20210301120526-00001.warc.gz"} |
https://worldwidescience.org/topicpages/m/multiple+independent+control.html | #### Sample records for multiple independent control
1. Multiple independent origins of mitochondrial control region duplications in the order Psittaciformes
Schirtzinger, Erin E.; Tavares, Erika S.; Gonzales, Lauren A.; Eberhard, Jessica R.; Miyaki, Cristina Y.; Sanchez, Juan J.; Hernandez, Alexis; Müeller, Heinrich; Graves, Gary R.; Fleischer, Robert C.; Wright, Timothy F.
2012-01-01
Mitochondrial genomes are generally thought to be under selection for compactness, due to their small size, consistent gene content, and a lack of introns or intergenic spacers. As more animal mitochondrial genomes are fully sequenced, rearrangements and partial duplications are being identified with increasing frequency, particularly in birds (Class Aves). In this study, we investigate the evolutionary history of mitochondrial control region states within the avian order Psittaciformes (parrots and cockatoos). To this aim, we reconstructed a comprehensive multi-locus phylogeny of parrots, used PCR of three diagnostic fragments to classify the mitochondrial control region state as single or duplicated, and mapped these states onto the phylogeny. We further sequenced 44 selected species to validate these inferences of control region state. Ancestral state reconstruction using a range of weighting schemes identified six independent origins of mitochondrial control region duplications within Psittaciformes. Analysis of sequence data showed that varying levels of mitochondrial gene and tRNA homology and degradation were present within a given clade exhibiting duplications. Levels of divergence between control regions within an individual varied from 0–10.9% with the differences occurring mainly between 51 and 225 nucleotides 3′ of the goose hairpin in domain I. Further investigations into the fates of duplicated mitochondrial genes, the potential costs and benefits of having a second control region, and the complex relationship between evolutionary rates, selection, and time since duplication are needed to fully explain these patterns in the mitochondrial genome. PMID:22543055
2. Multiple independent regulatory pathways control UBI4 expression after heat shock in Saccharomyces cerevisiae.
Simon, J R; Treger, J M; McEntee, K
1999-02-01
Transcription of the polyubiquitin gene UBI4 of Saccharomyces cerevisiae is strongly induced by a variety of environmental stresses, such as heat shock, nutrient depletion and exposure to DNA-damaging agents. This transcriptional response of UBI4 is likely to be the primary mechanism for increasing the pool of ubiquitin for degradation of stress-damaged proteins. Deletion and promoter fusion studies of the 5' regulatory sequences indicated that two different elements, heat shock elements (HSEs) and stress response element (STREs), contributed independently to heat shock regulation of the UBI4 gene. In the absence of HSEs, STRE sequences localized to the intervals -264 to -238 and -215 to -183 were needed for stress control of transcription after heat shock. Site-directed mutagenesis of the STRE (AG4) at -252 to -248 abolished heat shock induction of UBI4 transcription. Northern analysis demonstrated that cells containing either a temperature-sensitive HSF or non-functional Msn2p/Msn4p transcription factors induced high levels of UBI4 transcripts after heat shock. In cells deficient in both heat stress pathways, heat-induced UBI4 transcript levels were considerably lower but not abolished, suggesting a role for another factor(s) in stress control of its expression.
3. Multiple independent origins of mitochondrial control region duplications in the order Psittaciformes
Schirtzinger, Erin E.; Tavares, Erika S.; Gonzales, Lauren A.
2012-01-01
with increasing frequency, particularly in birds (Class Aves). In this study, we investigate the evolutionary history of mitochondrial control region states within the avian order Psittaciformes (parrots and cockatoos). To this aim, we reconstructed a comprehensive multi-locus phylogeny of parrots, used PCR...
4. Light-effect transistor (LET with multiple independent gating controls for optical logic gates and optical amplification
Jason eMarmon
2016-03-01
Full Text Available Modern electronics are developing electronic-optical integrated circuits, while their electronic backbone, e.g. field-effect transistors (FETs, remains the same. However, further FET down scaling is facing physical and technical challenges. A light-effect transistor (LET offers electronic-optical hybridization at the component level, which can continue Moore’s law to quantum region without requiring a FET’s fabrication complexity, e.g. physical gate and doping, by employing optical gating and photoconductivity. Multiple independent gates are therefore readily realized to achieve unique functionalities without increasing chip space. Here we report LET device characteristics and novel digital and analog applications, such as optical logic gates and optical amplification. Prototype CdSe-nanowire-based LETs show output and transfer characteristics resembling advanced FETs, e.g. on/off ratios up to ~1.0x106 with a source-drain voltage of ~1.43 V, gate-power of ~260 nW, and subthreshold swing of ~0.3 nW/decade (excluding losses. Our work offers new electronic-optical integration strategies and electronic and optical computing approaches.
5. Light-effect transistor (LET) with multiple independent gating controls for optical logic gates and optical amplification
Marmon, Jason; Rai, Satish; Wang, Kai; Zhou, Weilie; Zhang, Yong
The pathway for CMOS technology beyond the 5-nm technology node remains unclear for both physical and technological reasons. A new transistor paradigm is required. A LET (Marmon et. al., Front. Phys. 2016, 4, No. 8) offers electronic-optical hybridization at the component level, and is capable of continuing Moore's law to the quantum scale. A LET overcomes a FET's fabrication complexity, e.g., physical gate and doping, by employing optical gating and photoconductivity, while multiple independent, optical gates readily realize unique functionalities. We report LET device characteristics and novel digital and analog applications, such as optical logic gates and optical amplification. Prototype CdSe-nanowire-based LETs, incorporating an M-S-M structure, show output and transfer characteristics resembling advanced FETs, e.g., on/off ratios up to 106 with a source-drain voltage of 1.43V, gate-power of 260nW, and a subthreshold swing of 0.3nW/decade (excluding losses). A LET has potential for high-switching (THz) speeds and extremely low-switching energies (aJ) in the ballistic transport region. Our work offers new electronic-optical integration strategies for high speed and low energy computing approaches, which could potentially be extended to other materials and devices.
6. Multiple independent identification decisions: a method of calibrating eyewitness identifications.
Pryke, Sean; Lindsay, R C L; Dysart, Jennifer E; Dupuis, Paul
2004-02-01
Two experiments (N = 147 and N = 90) explored the use of multiple independent lineups to identify a target seen live. In Experiment 1, simultaneous face, body, and sequential voice lineups were used. In Experiment 2, sequential face, body, voice, and clothing lineups were used. Both studies demonstrated that multiple identifications (by the same witness) from independent lineups of different features are highly diagnostic of suspect guilt (G. L. Wells & R. C. L. Lindsay, 1980). The number of suspect and foil selections from multiple independent lineups provides a powerful method of calibrating the accuracy of eyewitness identification. Implications for use of current methods are discussed. ((c) 2004 APA, all rights reserved)
7. Multiple Hierarchies and Organizational Control
Evans, Peter B.
1975-01-01
Uses a control-loss model to explore the effects of multiple channels in formal organizations, and presents an argument for the superior control properties of dual hierarchies. Two variant forms of multiple hierarchies are considered. (Author)
8. Controleum - an independently extensible control system
Jensen, Martin Lykke Rytter
2014-01-01
challenging kind of system to design for independent extension. This thesis presents two new software technologies that improve the extensibility of control systems: First, the concept of dynamic links is introduced and Decouplink – an implementation of dynamic links for Java - is presented. Dynamic links...... is introduced, and an implementation is presented. The extensible controller is a component framework designed to automatically resolve conflicts among mutually unaware components in a control system. The solution is based on the idea that independent components implement different kinds of control concerns...
9. Multiple Independent Gate FETs: How Many Gates Do We Need?
Amarù, Luca; Hills, Gage; Gaillardon, Pierre-Emmanuel; Mitra, Subhasish; De Micheli, Giovanni
2015-01-01
Multiple Independent Gate Field Effect Transistors (MIGFETs) are expected to push FET technology further into the semiconductor roadmap. In a MIGFET, supplementary gates either provide (i) enhanced conduction properties or (ii) more intelligent switching functions. In general, each additional gate also introduces a side implementation cost. To enable more efficient digital systems, MIGFETs must leverage their expressive power to realize complex logic circuits with few physical resources. Rese...
10. Multiple Independent File Parallel I/O with HDF5
Miller, M. C.
2016-07-13
The HDF5 library has supported the I/O requirements of HPC codes at Lawrence Livermore National Labs (LLNL) since the late 90’s. In particular, HDF5 used in the Multiple Independent File (MIF) parallel I/O paradigm has supported LLNL code’s scalable I/O requirements and has recently been gainfully used at scales as large as O(106) parallel tasks.
Lovett, A; Rapaport, M S [Center for Nuclear Research, Soreq (Israel)
1980-12-01
A controller for an on-line three parameter coincidence and multispectra scaling system has been developed. It has been designed to control, event-by-event, the outputs of three nuclear analog-to-digital converters used at the SOLIS facility. The system utilizes an HP minicomputer with a 32k-word core memory, a disc drive and magnetic tape units.
12. Birth Control - Multiple Languages
... Methods - English PDF How to Switch Birth Control Methods - 简体中文 (Chinese, Simplified (Mandarin dialect)) ... Reproductive Health Access Project Non-Contraceptive Indications for Hormonal Contraceptive Products - English PDF Non- ...
13. PRKCA and multiple sclerosis: association in two independent populations.
Janna Saarela
2006-03-01
Full Text Available Multiple sclerosis (MS is a chronic disease of the central nervous system responsible for a large portion of neurological disabilities in young adults. Similar to what occurs in numerous complex diseases, both unknown environmental factors and genetic predisposition are required to generate MS. We ascertained a set of 63 Finnish MS families, originating from a high-risk region of the country, to identify a susceptibility gene within the previously established 3.4-Mb region on 17q24. Initial single nucleotide polymorphism (SNP-based association implicated PRKCA (protein kinase C alpha gene, and this association was replicated in an independent set of 148 Finnish MS families (p = 0.0004; remaining significant after correction for multiple testing. Further, a dense set of 211 SNPs evenly covering the PRKCA gene and the flanking regions was selected from the dbSNP database and analyzed in two large, independent MS cohorts: in 211 Finnish and 554 Canadian MS families. A multipoint SNP analysis indicated linkage to PRKCA and its telomeric flanking region in both populations, and SNP haplotype and genotype combination analyses revealed an allelic variant of PRKCA, which covers the region between introns 3 and 8, to be over-represented in Finnish MS cases (odds ratio = 1.34, 95% confidence interval 1.07-1.68. A second allelic variant, covering the same region of the PRKCA gene, showed somewhat stronger evidence for association in the Canadian families (odds ratio = 1.64, 95% confidence interval 1.39-1.94. Initial functional relevance for disease predisposition was suggested by the expression analysis: The transcript levels of PRKCA showed correlation with the copy number of the Finnish and Canadian "risk" haplotypes in CD4-negative mononuclear cells of five Finnish multiplex families and in lymphoblast cell lines of 11 Centre d'Etude du Polymorphisme Humain (CEPH individuals of European origin.
14. Integrated Production-Distribution Scheduling Problem with Multiple Independent Manufacturers
Jianhong Hao
2015-01-01
Full Text Available We consider the nonstandard parts supply chain with a public service platform for machinery integration in China. The platform assigns orders placed by a machinery enterprise to multiple independent manufacturers who produce nonstandard parts and makes production schedule and batch delivery schedule for each manufacturer in a coordinate manner. Each manufacturer has only one plant with parallel machines and is located at a location far away from other manufacturers. Orders are first processed at the plants and then directly shipped from the plants to the enterprise in order to be finished before a given deadline. We study the above integrated production-distribution scheduling problem with multiple manufacturers to maximize a weight sum of the profit of each manufacturer under the constraints that all orders are finished before the deadline and the profit of each manufacturer is not negative. According to the optimal condition analysis, we formulate the problem as a mixed integer programming model and use CPLEX to solve it.
15. MULTIPLE ECH LAUNCHER CONTROL SYSTEM
GREEN, M.T.; PONCE, D.; GRUNLOH, H.J.; ELLIS, R.A.; GROSNICKLE, W.H.; HUMPHREY, R.L.
2004-03-01
OAK-B135 The addition of new, high power gyrotrons to the heating and current drive arsenal at DIII-D, required a system upgrade for control of fully steerable ECH Launchers. Each launcher contains two pointing mirrors with two degrees of mechanical freedom. The two flavors of motion are called facet and tilt. Therefore up to four channels of motion per launcher need to be controlled. The system utilizes absolute encoders to indicate mirror position and therefore direction of the microwave beam. The launcher movement is primarily controlled by PLC, but future iterations of design, may require this control to be accomplished by a CPU on fast bus such as Compact PCI. This will be necessary to accomplish real time position control. Safety of equipment and personnel is of primary importance when controlling a system of moving parts. Therefore multiple interlocks and fault status enunciators have been implemented. This paper addresses the design of a Multiple ECH Launcher Control System, and characterizes the flexibility needed to upgrade to a real time position control system in the future
16. A New Generalized Two-Stage Direct Power Conversion Topology to Independently Supply Multiple AC Loads from Multiple Power Grids with Adjustable Power Loading
Klumpner, Christian; Blaabjerg, Frede
2004-01-01
) and continuously adjust these power fractions will become a desired feature. This paper presents a generalized Direct Power Converter topology, which is able to connect to multiple AC supplies proving complete decoupling and no circulating power between the input ports and to independently control multiple AC...
17. How multiple causes combine: independence constraints on causal inference.
Liljeholm, Mimi
2015-01-01
According to the causal power view, two core constraints-that causes occur independently (i.e., no confounding) and influence their effects independently-serve as boundary conditions for causal induction. This study investigated how violations of these constraints modulate uncertainty about the existence and strength of a causal relationship. Participants were presented with pairs of candidate causes that were either confounded or not, and that either interacted or exerted their influences independently. Consistent with the causal power view, uncertainty about the existence and strength of causal relationships was greater when causes were confounded or interacted than when unconfounded and acting independently. An elemental Bayesian causal model captured differences in uncertainty due to confounding but not those due to an interaction. Implications of distinct sources of uncertainty for the selection of contingency information and causal generalization are discussed.
18. Stator for a rotating electrical machine having multiple control windings
Shah, Manoj R.; Lewandowski, Chad R.
2001-07-17
A rotating electric machine is provided which includes multiple independent control windings for compensating for rotor imbalances and for levitating/centering the rotor. The multiple independent control windings are placed at different axial locations along the rotor to oppose forces created by imbalances at different axial locations along the rotor. The multiple control windings can also be used to levitate/center the rotor with a relatively small magnetic field per unit area since the rotor and/or the main power winding provides the bias field.
19. Residual dipolar couplings: are multiple independent alignments always possible?
Higman, Victoria A.; Boyd, Jonathan; Smith, Lorna J.; Redfield, Christina
2011-01-01
RDCs for the 14 kDa protein hen egg-white lysozyme (HEWL) have been measured in eight different alignment media. The elongated shape and strongly positively charged surface of HEWL appear to limit the protein to four main alignment orientations. Furthermore, low levels of alignment and the protein’s interaction with some alignment media increases the experimental error. Together with heterogeneity across the alignment media arising from constraints on temperature, pH and ionic strength for some alignment media, these data are suitable for structure refinement, but not the extraction of dynamic parameters. For an analysis of protein dynamics the data must be obtained with very low errors in at least three or five independent alignment media (depending on the method used) and so far, such data have only been reported for three small 6–8 kDa proteins with identical folds: ubiquitin, GB1 and GB3. Our results suggest that HEWL is likely to be representative of many other medium to large sized proteins commonly studied by solution NMR. Comparisons with over 60 high-resolution crystal structures of HEWL reveal that the highest resolution structures are not necessarily always the best models for the protein structure in solution.
20. Intelligent energy management control for independent microgrid
Energy management control; multi-agent system; microgrid; energy forecast; hybrid power ... power to the local load most of the time in this energy management strategy. ... Electrical and Electronics Engineering Department, PSG College of ...
1. The Multiple Control of Verbal Behavior
Michael, Jack; Palmer, David C.; Sundberg, Mark L.
2011-01-01
Amid the novel terms and original analyses in Skinner's "Verbal Behavior", the importance of his discussion of multiple control is easily missed, but multiple control of verbal responses is the rule rather than the exception. In this paper we summarize and illustrate Skinner's analysis of multiple control and introduce the terms "convergent…
2. Organization and control of independent work of students
Kaydalova L.G.
2010-01-01
Full Text Available The theoretical methodical aspects of independent work of students, organization and control, educational methodical providing, forms and types of independent work are examined. Efficiency of independent work is provided high-quality educational literature. The basic forms of control is: current, result and module, examinations, term papers, diploma works, licensed computer-integrated examinations, state attestation. Control can be conducted in a kind: expressquestioning, interview. Control is an information generator for a teacher about motion of independent capture the student of educational by material.
3. Active control of multiple resistive wall modes
Brunsell, P. R.; Yadikin, D.; Gregoratto, D.; Paccagnella, R.; Liu, Y. Q.; Bolzonella, T.; Cecconello, M.; Drake, J. R.; Kuldkepp, M.; Manduchi, G.; Marchiori, G.; Marrelli, L.; Partin, P.; Menmuir, S.; Ortolani, S.; Rachlew, E.; Spizzo, S.; Zanca, P.
2005-01-01
Active magnetic feedback suppression of resistive wall modes is of common interest for several fusion concepts relying on close conducting walls for stabilization of ideal magnetohydrodynamic (MHD) modes. In the advanced tokamak without plasma rotation the kink mode is not completely stabilized, but rather converted into an unstable resistive wall mode (RWM) with a growth time comparable to the wall magnetic flux penetration time. The reversed field pinch (RFP) is similar to the advanced tokamak in the sense that it uses a conducting wall for kink mode stabilization. Also both configurations are susceptible to resonant field error amplification of marginally stable modes. However, the RFP has a different RWM spectrum and, in general, a range of modes is unstable. Hence, the requirement for simultaneous feedback stabilization of multiple independent RWMs arises for the RFP configuration. Recent experiments on RWM feedback stabilization, performed in the RFP device EXTRAP T2R [1], are presented. The experimental results obtained are the first demonstration of simultaneous feedback control of multiple independent RWMs [2]. Using an array of active magnetic coils, a reproducible suppression of several RWMs is achieved for the duration of the discharge, 3-5 wall times, through feedback action. An array with 64 active saddle coils at 4 poloidal times 16 toroidal positions is used. The important issues of side band generation by the active coil array and the accompanying coupling of different unstable modes through the feedback action are addressed in this study. Open loop control experiments have been carried out to quantitatively study resonant field error amplification. (Author)
4. Future independent power generation and implications for instruments and controls
Williams, J.H.
1991-01-01
This paper reports that the independent power producers market is comprised of cogeneration, small power generation, and independent power production (IPP) segments. Shortfalls in future electric supply are expected to lead to significant growth in this market. The opportunities for instruments and controls will shift from traditional electric utility applications to the independent power market with a more diverse set of needs. Importance will be placed on system reliability, quality of power and increased demand for clean kWh
5. The Research of Multiple Attenuation Based on Feedback Iteration and Independent Component Analysis
Xu, X.; Tong, S.; Wang, L.
2017-12-01
How to solve the problem of multiple suppression is a difficult problem in seismic data processing. The traditional technology for multiple attenuation is based on the principle of the minimum output energy of the seismic signal, this criterion is based on the second order statistics, and it can't achieve the multiple attenuation when the primaries and multiples are non-orthogonal. In order to solve the above problems, we combine the feedback iteration method based on the wave equation and the improved independent component analysis (ICA) based on high order statistics to suppress the multiple waves. We first use iterative feedback method to predict the free surface multiples of each order. Then, in order to predict multiples from real multiple in amplitude and phase, we design an expanded pseudo multi-channel matching filtering method to get a more accurate matching multiple result. Finally, we present the improved fast ICA algorithm which is based on the maximum non-Gauss criterion of output signal to the matching multiples and get better separation results of the primaries and the multiples. The advantage of our method is that we don't need any priori information to the prediction of the multiples, and can have a better separation result. The method has been applied to several synthetic data generated by finite-difference model technique and the Sigsbee2B model multiple data, the primaries and multiples are non-orthogonal in these models. The experiments show that after three to four iterations, we can get the perfect multiple results. Using our matching method and Fast ICA adaptive multiple subtraction, we can not only effectively preserve the effective wave energy in seismic records, but also can effectively suppress the free surface multiples, especially the multiples related to the middle and deep areas.
6. Consensus of multiple autonomous underwater vehicles with double independent Markovian switching topologies and timevarying delays
Yan Zhe-Ping; Liu Yi-Bo; Zhou Jia-Jia; Zhang Wei; Wang Lu
2017-01-01
A new method in which the consensus algorithm is used to solve the coordinate control problems of leaderless multiple autonomous underwater vehicles (multi-AUVs) with double independent Markovian switching communication topologies and time-varying delays among the underwater sensors is investigated. This is accomplished by first dividing the communication topology into two different switching parts, i.e., velocity and position, to reduce the data capacity per data package sent between the multi-AUVs in the ocean. Then, the state feedback linearization is used to simplify and rewrite the complex nonlinear and coupled mathematical model of the AUVs into a double-integrator dynamic model. Consequently, coordinate control of the multi-AUVs is regarded as an approximating consensus problem with various time-varying delays and velocity and position topologies. Considering these factors, sufficient conditions of consensus control are proposed and analyzed and the stability of the multi-AUVs is proven by Lyapunov–Krasovskii theorem. Finally, simulation results that validate the theoretical results are presented. (paper)
7. Independent directors’ board networks and controlling shareholders’ tunneling behavior
Chen, Yunsen; Wang, Yutao; Lin, Le
2014-01-01
As one of the channels by which board directors build important relationships, board networks can affect the governance role of independent directors. Defining director board networks as their connections based on direct ties they establish when serving on at least one common board, this paper explores the role of the network centrality of independent directors in restraining tunneling behavior by controlling shareholders in the Chinese capital market. Our empirical evidence shows that tunnel...
8. Multiplicity Control in Structural Equation Modeling
Cribbie, Robert A.
2007-01-01
Researchers conducting structural equation modeling analyses rarely, if ever, control for the inflated probability of Type I errors when evaluating the statistical significance of multiple parameters in a model. In this study, the Type I error control, power and true model rates of famsilywise and false discovery rate controlling procedures were…
9. The frequency-independent control method for distributed generation systems
Naderi, Siamak; Pouresmaeil, Edris; Gao, Wenzhong David
2012-01-01
In this paper a novel frequency-independent control method suitable for distributed generation (DG) is presented. This strategy is derived based on the . abc/. αβ transformation and . abc/. dq transformation of the ac system variables. The active and reactive currents injected by the DG are contr......In this paper a novel frequency-independent control method suitable for distributed generation (DG) is presented. This strategy is derived based on the . abc/. αβ transformation and . abc/. dq transformation of the ac system variables. The active and reactive currents injected by the DG...
10. Datafish Multiphase Data Mining Technique to Match Multiple Mutually Inclusive Independent Variables in Large PACS Databases.
Kelley, Brendan P; Klochko, Chad; Halabi, Safwan; Siegal, Daniel
2016-06-01
Retrospective data mining has tremendous potential in research but is time and labor intensive. Current data mining software contains many advanced search features but is limited in its ability to identify patients who meet multiple complex independent search criteria. Simple keyword and Boolean search techniques are ineffective when more complex searches are required, or when a search for multiple mutually inclusive variables becomes important. This is particularly true when trying to identify patients with a set of specific radiologic findings or proximity in time across multiple different imaging modalities. Another challenge that arises in retrospective data mining is that much variation still exists in how image findings are described in radiology reports. We present an algorithmic approach to solve this problem and describe a specific use case scenario in which we applied our technique to a real-world data set in order to identify patients who matched several independent variables in our institution's picture archiving and communication systems (PACS) database.
11. Iron deposition is independent of cellular inflammation in a cerebral model of multiple sclerosis
Lee Phil
2011-06-01
Full Text Available Abstract Background Perivenular inflammation is a common early pathological feature in multiple sclerosis (MS. A recent hypothesis stated that CNS inflammation is induced by perivenular iron deposits that occur in response to altered blood flow in MS subjects. In order to evaluate this hypothesis, an animal model was developed, called cerebral experimental autoimmune encephalomyelitis (cEAE, which presents with CNS perivascular iron deposits. This model was used to investigate the relationship of iron deposition to inflammation. Methods In order to generate cEAE, mice were given an encephalitogen injection followed by a stereotactic intracerebral injection of TNF-α and IFN-γ. Control animals received encephalitogen followed by an intracerebral injection of saline, or no encephalitogen plus an intracerebral injection of saline or cytokines. Laser Doppler was used to measure cerebral blood flow. MRI and iron histochemistry were used to localize iron deposits. Additional histological procedures were used to localize inflammatory cell infiltrates, microgliosis and astrogliosis. Results Doppler analysis revealed that cEAE mice had a reduction in cerebral blood flow compared to controls. MRI revealed T2 hypointense areas in cEAE animals that spatially correlated with iron deposition around vessels and at some sites of inflammation as detected by iron histochemistry. Vessels with associated iron deposits were distributed across both hemispheres. Mice with cEAE had more iron-labeled vessels compared to controls, but these vessels were not commonly associated with inflammatory cell infiltrates. Some iron-laden vessels had associated microgliosis that was above the background microglial response, and iron deposits were observed within reactive microglia. Vessels with associated astrogliosis were more commonly observed without colocalization of iron deposits. Conclusion The findings indicate that iron deposition around vessels can occur independently of
12. AC machine control : robust and sensorless control by parameter independency
Samuelsen, Dag Andreas Hals
2009-06-15
In this thesis it is first presented how robust control can be used to give AC motor drive systems competitive dynamic performance under parameter variations. These variations are common to all AC machines, and are a result of temperature change in the machine, and imperfect machine models. This robust control is, however, dependent on sensor operation in the sense that the rotor position is needed in the control loop. Elimination of this control loop has been for many years, and still is, a main research area of AC machines control systems. An integrated PWM modulator and sampler unit has been developed and tested. The sampler unit is able to give current and voltage measurements with a reduced noise component. It is further used to give the true derivative of currents and voltages in the machine and the power converter, as an average over a PWM period, and as separate values for all states of the power converter. In this way, it can give measurements of the currents as well as the derivative of the currents, at the start and at the end of a single power inverter state. This gave a large degree of freedom in parameter and state identification during uninterrupted operation of the induction machine. The special measurement scheme of the system achieved three main goals: By avoiding the time frame where the transistors commutate and the noise in the measurement of the current is large, filtering of the current measurement is no longer needed. The true derivative of the current in the machine is can be measured with far less noise components. This was extended to give any separate derivative in all three switching states of the power converter. Using the computational resources of the FPGA, more advanced information was supplied to the control system, in order to facilitate sensor less operation, with low computational demands on the DSP. As shown in the papers, this extra information was first used to estimate some of the states of the machine, in some or all of the
13. Multilateral Telecoordinated Control of Multiple Robots With Uncertain Kinematics.
Zhai, Di-Hua; Xia, Yuanqing
2017-06-06
This paper addresses the telecoordinated control of multiple robots in the simultaneous presence of asymmetric time-varying delays, nonpassive external forces, and uncertain kinematics/dynamics. To achieve the control objective, a neuroadaptive controller with utilizing prescribed performance control and switching control technique is developed, where the basic idea is to employ the concept of motion synchronization in each pair of master-slave robots and among all slave robots. By using the multiple Lyapunov-Krasovskii functionals method, the state-independent input-to-output practical stability of the closed-loop system is established. Compared with the previous approaches, the new design is straightforward and easier to implement and is applicable to a wider area. Simulation results on three pairs of three degrees-of-freedom robots confirm the theoretical findings.
14. Control of multiple robots using vision sensors
Aranda, Miguel; Sagüés, Carlos
2017-01-01
This monograph introduces novel methods for the control and navigation of mobile robots using multiple-1-d-view models obtained from omni-directional cameras. This approach overcomes field-of-view and robustness limitations, simultaneously enhancing accuracy and simplifying application on real platforms. The authors also address coordinated motion tasks for multiple robots, exploring different system architectures, particularly the use of multiple aerial cameras in driving robot formations on the ground. Again, this has benefits of simplicity, scalability and flexibility. Coverage includes details of: a method for visual robot homing based on a memory of omni-directional images a novel vision-based pose stabilization methodology for non-holonomic ground robots based on sinusoidal-varying control inputs an algorithm to recover a generic motion between two 1-d views and which does not require a third view a novel multi-robot setup where multiple camera-carrying unmanned aerial vehicles are used to observe and c...
15. Conceptual design of multiple parallel switching controller
Ugolini, D.; Yoshikawa, S.; Ozawa, K.
1996-01-01
This paper discusses the conceptual design and the development of a preliminary model of a multiple parallel switching (MPS) controller. The introduction of several advanced controllers has widened and improved the control capability of nonlinear dynamical systems. However, it is not possible to uniquely define a controller that always outperforms the others, and, in many situations, the controller providing the best control action depends on the operating conditions and on the intrinsic properties and behavior of the controlled dynamical system. The desire to combine the control action of several controllers with the purpose to continuously attain the best control action has motivated the development of the MPS controller. The MPS controller consists of a number of single controllers acting in parallel and of an artificial intelligence (AI) based selecting mechanism. The AI selecting mechanism analyzes the output of each controller and implements the one providing the best control performance. An inherent property of the MPS controller is the possibility to discard unreliable controllers while still being able to perform the control action. To demonstrate the feasibility and the capability of the MPS controller the simulation of the on-line operation control of a fast breeder reactor (FBR) evaporator is presented. (author)
16. Delegation control of multiple unmanned systems
Flaherty, Susan R.; Shively, Robert J.
2010-04-01
Maturing technologies and complex payloads coupled with a future objective to reduce the logistics burden of current unmanned aerial systems (UAS) operations require a change to the 2-crew employment paradigm. Increased automation and operator supervisory control of unmanned systems have been advocated to meet the objective of reducing the crew requirements, while managing future technologies. Specifically, a delegation control employment strategy has resulted in reduced workload and higher situation awareness for single operators controlling multiple unmanned systems in empirical studies1,2. Delegation control is characterized by the ability for an operator to call a single "play" that initiates prescribed default actions for each vehicle and associated sensor related to a common mission goal. Based upon the effectiveness of delegation control in simulation, the U.S. Army Aeroflightdynamics Directorate (AFDD) developed a Delegation Control (DelCon) operator interface with voice recognition implementation for play selection, real-time play modification, and play status with automation transparency to enable single operator control of multiple unmanned systems in flight. AFDD successfully demonstrated delegation control in a Troops-in-Contact mission scenario at Ft. Ord in 2009. This summary showcases the effort as a beneficial advance in single operator control of multiple UAS.
17. IMPROVING FUNCTIONAL INDEPENDENCE OF PATIENTS WITH MULTIPLE SCLEROSIS BY PHYSICAL THERAPY AND OCCUPATIONAL THERAPY
Ana-Maria Ticărat
2011-06-01
Full Text Available Introduction. Patients with multiple sclerosis can have a normal life despite of their real or possible disability and of the progressive nature of it. Scope. Patients who follow physical therapy and occupational therapy will have an increased quality of life and a greater functional independence.Methods. The randomized study was made on 7 patients with multiple sclerosis, from Oradea Day Centre, 3 times/week, ages between 35 – 55 years, functional level between mild and sever. Assessment and rehabilitation methods: inspection, BARTHEL Index. Frenkel method, brething exercises, weights exercises, gait exercises, writind exercises and games were used in the rehabilitation process. Group therapies: sociotherapy, arttherapy, music therapy. Results analysis consisted of the comparison of baseline and final means.Results. By analizing baseline and final means for Barthel Index for each functon separately, it was shown a mild improvement of functional independence for almost assessed functions, with at least 1-1,5 points.Conclusions. Persons with multiple sclerosis who follow physical therapy and occupational therapy presents a better functional independence after the treatment.
18. Characterizing functional connectivity during rest in multiple sclerosis patients versus healthy volunteers using independent component analysis
Palacio Garcia, L.; Andrzejak, R.; Prchkovska, V.; Rodrigues, P.
2016-07-01
It is commonly thought that our brain is not active when it does not receive any external input. However, during rest, there are still certain distant regions of the brain that are functionally correlated between them: the so-called resting-state networks. This functional connectivity of the brain is disrupted in many neurological diseases. In particular, it has been shown that one of the most studied resting-state networks (the default-mode network) is affected in multiple sclerosis, which is the most common disabling neurological condition affecting the central nervous system of young adults. In this work, I focus on the study of the differences in the resting-state networks between multiple sclerosis patients and healthy volunteers. In order to study the effects of multiple sclerosis on the functional connectivity of the brain, a numerical method known as independent component analysis (ICA) is applied. This technique divides the resting-state fMRI data into independent components. Nonetheless, noise, which could be due to head motion or physiological artifacts, may corrupt the data by indicating a false activation. Therefore, I create a web user interface that allows the user to manually classify all the independent components for a given subject. Eventually, the components classified as noise should be removed from the functional data in order to prevent them from taking part in any further analysis. (Author)
19. The independence of the CSN and Parliamentary control
2006-01-01
The Chairman of the Congressional Commission for Industry, Tourism and commerce underlines the link between the CSN and Parliament, to which the Council is accountable via control mechanisms that have improved over the years. he also points to the fact that the obligatory compliance with the resolutions approved has implied improvements in the structure and operation of the regulator. In winding up, the trusts that the modification of the Law which the council was created will promote the independence of the organisation with respect to the legitimate interests of industry, the democratic control exercised by Parliament and transparency before the public. (Author)
20. Multiple model adaptive control with mixing
Kuipers, Matthew
1. ASSISTments Dataset from Multiple Randomized Controlled Experiments
Selent, Douglas; Patikorn, Thanaporn; Heffernan, Neil
2016-01-01
In this paper, we present a dataset consisting of data generated from 22 previously and currently running randomized controlled experiments inside the ASSISTments online learning platform. This dataset provides data mining opportunities for researchers to analyze ASSISTments data in a convenient format across multiple experiments at the same time.…
2. Cooperative Control of Multiple Unmanned Autonomous Vehicles
2005-06-03
I I Final Report 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS Cooperative Control of Multiple Unmanned Autonomous Vehicles F49620-01-1-0337 6. AUTHOR(S... Autonomous Vehicles Final Report Kendall E. Nygard Department of Computer Science and Operations Research North Dakota State University Fargo, ND 58105-5164
3. Speed invariance of independent control of finger movements in pianists.
Furuya, Shinichi; Soechting, John F
2012-10-01
Independent control of finger movements characterizes skilled motor behaviors such as tool use and musical performance. The purpose of the present study was to identify the effect of movement frequency (tempo) on individuated finger movements in piano playing. Joint motion at the digits was recorded while 5 expert pianists were playing 30 excerpts from musical pieces with different fingering and key locations either at a predetermined normal tempo or as fast as possible. Principal component analysis and cluster analysis using an expectation-maximization algorithm determined three distinct patterns of finger movement coordination for a keypress with each of the index, middle, ring, and little fingers at each of the two tempi. The finger kinematics of each coordination pattern was overall similar across the tempi. Tone sequences assigned into each cluster were also similar for both tempi. A linear regression analysis determined no apparent difference in the amount of movement covariation between the striking and nonstriking fingers at both metacarpo-phalangeal and proximal-interphalangeal joints across the two tempi, which indicated no effect of tempo on independent finger movements in piano playing. In addition, the standard deviation of interkeystroke interval across strokes did not differ between the two tempi, indicating maintenance of rhythmic accuracy of keystrokes. Strong temporal constraints on finger movements during piano playing may underlie the maintained independent control of fingers over a wider range of tempi, a feature being likely to be specific to skilled pianists.
4. Multiple independent variants at the TERT locus are associated with telomere length and risks of breast and ovarian cancer
Bojesen, Stig E; Pooley, Karen A; Johnatty, Sharon E; Beesley, Jonathan; Michailidou, Kyriaki; Tyrer, Jonathan P; Edwards, Stacey L; Pickett, Hilda A; Shen, Howard C; Smart, Chanel E; Hillman, Kristine M; Mai, Phuong L; Lawrenson, Kate; Stutz, Michael D; Lu, Yi
2013-01-01
TERT-locus single nucleotide polymorphisms (SNPs) and leucocyte telomere measures are reportedly associated with risks of multiple cancers. Using the iCOGs chip, we analysed ~480 TERT-locus SNPs in breast (n=103,991), ovarian (n=39,774) and BRCA1 mutation carrier (11,705) cancer cases and controls. 53,724 participants have leucocyte telomere measures. Most associations cluster into three independent peaks. Peak 1 SNP rs2736108 minor allele associates with longer telomeres (P=5.8×10−7), reduce...
5. Distributed Autonomous Control of Multiple Spacecraft During Close Proximity Operations
McCamish, Shawn B
2007-01-01
This research contributes to multiple spacecraft control by developing an autonomous distributed control algorithm for close proximity operations of multiple spacecraft systems, including rendezvous...
6. Dynamic coordinated control laws in multiple agent models
Morgan, David S.; Schwartz, Ira B.
2005-01-01
We present an active control scheme of a kinetic model of swarming. It has been shown previously that the global control scheme for the model, presented in [Systems Control Lett. 52 (2004) 25], gives rise to spontaneous collective organization of agents into a unified coherent swarm, via steering controls and utilizing long-range attractive and short-range repulsive interactions. We extend these results by presenting control laws whereby a single swarm is broken into independently functioning subswarm clusters. The transition between one coordinated swarm and multiple clustered subswarms is managed simply with a homotopy parameter. Additionally, we present as an alternate formulation, a local control law for the same model, which implements dynamic barrier avoidance behavior, and in which swarm coherence emerges spontaneously
7. Realization of quantum gates with multiple control qubits or multiple target qubits in a cavity
2015-06-01
We propose a scheme to realize a three-qubit controlled phase gate and a multi-qubit controlled NOT gate of one qubit simultaneously controlling n-target qubits with a four-level quantum system in a cavity. The implementation time for multi-qubit controlled NOT gate is independent of the number of qubit. Three-qubit phase gate is generalized to n-qubit phase gate with multiple control qubits. The number of steps reduces linearly as compared to conventional gate decomposition method. Our scheme can be applied to various types of physical systems such as superconducting qubits coupled to a resonator and trapped atoms in a cavity. Our scheme does not require adjustment of level spacing during the gate implementation. We also show the implementation of Deutsch-Joza algorithm. Finally, we discuss the imperfections due to cavity decay and the possibility of physical implementation of our scheme.
8. Decentralized fuzzy control of multiple nonholonomic vehicles
Driessen, B.J.; Feddema, J.T.; Kwok, K.S.
1997-09-01
This work considers the problem of controlling multiple nonholonomic vehicles so that they converge to a scent source without colliding with each other. Since the control is to be implemented on simple 8-bit microcontrollers, fuzzy control rules are used to simplify a linear quadratic regulator control design. The inputs to the fuzzy controllers for each vehicle are the (noisy) direction to the source, the distance to the closest neighbor vehicle, and the direction to the closest vehicle. These directions are discretized into four values: Forward, Behind, Left, and Right, and the distance into three values: Near, Far, Gone. The values of the control at these discrete values are obtained based on the collision-avoidance repulsive forces and the change of variables that reduces the motion control problem of each nonholonomic vehicle to a nonsingular one with two degrees of freedom, instead of three. A fuzzy inference system is used to obtain control values for inputs between the small number of discrete input values. Simulation results are provided which demonstrate that the fuzzy control law performs well compared to the exact controller. In fact, the fuzzy controller demonstrates improved robustness to noise.
9. Phylogeographic and population genetic analyses reveal multiple species of Boa and independent origins of insular dwarfism.
Card, Daren C; Schield, Drew R; Adams, Richard H; Corbin, Andrew B; Perry, Blair W; Andrew, Audra L; Pasquesi, Giulia I M; Smith, Eric N; Jezkova, Tereza; Boback, Scott M; Booth, Warren; Castoe, Todd A
2016-09-01
Boa is a Neotropical genus of snakes historically recognized as monotypic despite its expansive distribution. The distinct morphological traits and color patterns exhibited by these snakes, together with the wide diversity of ecosystems they inhabit, collectively suggest that the genus may represent multiple species. Morphological variation within Boa also includes instances of dwarfism observed in multiple offshore island populations. Despite this substantial diversity, the systematics of the genus Boa has received little attention until very recently. In this study we examined the genetic structure and phylogenetic relationships of Boa populations using mitochondrial sequences and genome-wide SNP data obtained from RADseq. We analyzed these data at multiple geographic scales using a combination of phylogenetic inference (including coalescent-based species delimitation) and population genetic analyses. We identified extensive population structure across the range of the genus Boa and multiple lines of evidence for three widely-distributed clades roughly corresponding with the three primary land masses of the Western Hemisphere. We also find both mitochondrial and nuclear support for independent origins and parallel evolution of dwarfism on offshore island clusters in Belize and Cayos Cochinos Menor, Honduras. Copyright © 2016 Elsevier Inc. All rights reserved.
10. Stability analysis of multiple-robot control systems
Wen, John T.; Kreutz, Kenneth
1989-01-01
In a space telerobotic service scenario, cooperative motion and force control of multiple robot arms are of fundamental importance. Three paradigms to study this problem are proposed. They are distinguished by the set of variables used for control design. They are joint torques, arm tip force vectors, and an accelerated generalized coordinate set. Control issues related to each case are discussed. The latter two choices require complete model information, which presents practical modeling, computational, and robustness problems. Therefore, focus is on the joint torque control case to develop relatively model independent motion and internal force control laws. The rigid body assumption allows the motion and force control problems to be independently addressed. By using an energy motivated Lyapunov function, a simple proportional derivative plus gravity compensation type of motion control law is always shown to be stabilizing. The asymptotic convergence of the tracing error to zero requires the use of a generalized coordinate with the contact constraints taken into account. If a non-generalized coordinate is used, only convergence to a steady state manifold can be concluded. For the force control, both feedforward and feedback schemes are analyzed. The feedback control, if proper care has been taken, exhibits better robustness and transient performance.
11. Multiple descriptions for packetized predictive control
Østergaard, Jan; Quevedo, Daniel
2016-01-01
be reliably reconstructed at the plant side. For the particular case of LTI plant models and i.i.d. channels, we show that the overall system forms a Markov jump linear system. We provide conditions for mean square stability and derive upper bounds on the operational bit rate of the quantizer to guarantee......In this paper, we propose to use multiple descriptions (MDs) to achieve a high degree of robustness towards random packet delays and erasures in networked control systems. In particular, we consider the scenario, where a data-rate limited channel is located between the controller and the plant...
12. The control of independent students’ work effectiveness during pathophysiology study
О. V. Melnikova
2013-06-01
Full Text Available The course of Pathophysiology study includes both auditoria hours (lectures and practical classes and independent work of students. The latter makes up 38% of total hours given for Pathophysiology study. Independent work of students includes the following items: preparation for practical classes, writing reviews on different topics, preparation for current and final computer testing, study of the topics which are not discussed during lectures and practical classes. In order to assimilate the course of Pathophysiology completely students should effectively use their hours given for independent work. Unfortunately, the level of students’ independent individual work is low; it includes only learning of single facts, that is not enough for higher medical education. THE AIM OF STUDY: To propose the method of control of the effectiveness of students’ independent work. The most important part of student’s individual work is preparation for study in auditoria, because it determines the qualitative level of study during practical classes. The student should enter the class not only with the knowledge of basic sciences (Anatomy, Histology, Biochemistry, Normal Physiology etc. but also with the understanding of key items of the topic of the practical class. The problem consists in the following: the teacher can’t check the level of basic knowledge in each student – there is not enough time during practical class for this procedure. In order to increase the effectiveness of individual students’ work a special workbook for the practical classes was developed at the Pathophysiology department. While preparing for practical classes students write down basic items of the topic, refresh some questions from Normal Physiology, Biochemistry and other subjects. In the beginning of the practical class the teacher controls the level of student’s preparation to the topic by checking the fulfillment of tasks in the workbook. It takes a little time, but it
13. Evidence for Multiple Mediator Complexes in Yeast Independently Recruited by Activated Heat Shock Factor.
Anandhakumar, Jayamani; Moustafa, Yara W; Chowdhary, Surabhi; Kainth, Amoldeep S; Gross, David S
2016-07-15
Mediator is an evolutionarily conserved coactivator complex essential for RNA polymerase II transcription. Although it has been generally assumed that in Saccharomyces cerevisiae, Mediator is a stable trimodular complex, its structural state in vivo remains unclear. Using the "anchor away" (AA) technique to conditionally deplete select subunits within Mediator and its reversibly associated Cdk8 kinase module (CKM), we provide evidence that Mediator's tail module is highly dynamic and that a subcomplex consisting of Med2, Med3, and Med15 can be independently recruited to the regulatory regions of heat shock factor 1 (Hsf1)-activated genes. Fluorescence microscopy of a scaffold subunit (Med14)-anchored strain confirmed parallel cytoplasmic sequestration of core subunits located outside the tail triad. In addition, and contrary to current models, we provide evidence that Hsf1 can recruit the CKM independently of core Mediator and that core Mediator has a role in regulating postinitiation events. Collectively, our results suggest that yeast Mediator is not monolithic but potentially has a dynamic complexity heretofore unappreciated. Multiple species, including CKM-Mediator, the 21-subunit core complex, the Med2-Med3-Med15 tail triad, and the four-subunit CKM, can be independently recruited by activated Hsf1 to its target genes in AA strains. Copyright © 2016, American Society for Microbiology. All Rights Reserved.
14. Mediator independently orchestrates multiple steps of preinitiation complex assembly in vivo.
Eyboulet, Fanny; Wydau-Dematteis, Sandra; Eychenne, Thomas; Alibert, Olivier; Neil, Helen; Boschiero, Claire; Nevers, Marie-Claire; Volland, Hervé; Cornu, David; Redeker, Virginie; Werner, Michel; Soutourina, Julie
2015-10-30
Mediator is a large multiprotein complex conserved in all eukaryotes, which has a crucial coregulator function in transcription by RNA polymerase II (Pol II). However, the molecular mechanisms of its action in vivo remain to be understood. Med17 is an essential and central component of the Mediator head module. In this work, we utilised our large collection of conditional temperature-sensitive med17 mutants to investigate Mediator's role in coordinating preinitiation complex (PIC) formation in vivo at the genome level after a transfer to a non-permissive temperature for 45 minutes. The effect of a yeast mutation proposed to be equivalent to the human Med17-L371P responsible for infantile cerebral atrophy was also analyzed. The ChIP-seq results demonstrate that med17 mutations differentially affected the global presence of several PIC components including Mediator, TBP, TFIIH modules and Pol II. Our data show that Mediator stabilizes TFIIK kinase and TFIIH core modules independently, suggesting that the recruitment or the stability of TFIIH modules is regulated independently on yeast genome. We demonstrate that Mediator selectively contributes to TBP recruitment or stabilization to chromatin. This study provides an extensive genome-wide view of Mediator's role in PIC formation, suggesting that Mediator coordinates multiple steps of a PIC assembly pathway. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.
15. Towards functional specification independent of control system suppliers
Galara, D.; Leret, E.
1997-01-01
For the next nuclear power plant generation, REP 2000, the Engineering and construction Division (ED) and the Research and development Division (R and D) of Electricite de France are working together in the field of Instrumentation and Control (I and C) to improve its engineering method and tools. This method and these tools are defined on the basis of the experience feedback from the N4 nuclear power plant generation and the current information technology, to improve engineering competitiveness and quality of control applications. We intend to decouple the I and C processing from the I and C Human Machine Interface (HMI), because methods and tools are different. In this paper, we only focus on method and tools for I and C processing. We define the I and C processing life cycle into three phases. The first phase is the specification of the control application processing, the product of which is called Functional Requirement Diagrams (FRDs). The second phase is the design of the I and C system. This phase is subdivided into two steps. The step 1 is the distribution of the FRDs into an I and C architecture. The step 2 is the allocation of resources of the I and C system, to support the distributed FRDs. The third phase is the implementation of the distributed FRDs into I and C equipment. The aim of the Engineering Division is to achieve formal FRDs, independent of I and C suppliers. This allows a large improvement for the quality of the specification and the dimensioning of the I and C system before calls for tenders. For the specification phase, studies are almost completed. For the design and the implementation phases, studies and experiments are in progress with European I and C system suppliers. As a conclusion, we present the interest of EDF for standards and especially IEC 1131 improvements. (author). 5 figs
16. Towards functional specification independent of control system suppliers
Galara, D; Leret, E [Electricite de France, Research and Development Div., Power Plant Control Branch, Chatou (France)
1997-07-01
For the next nuclear power plant generation, REP 2000, the Engineering and construction Division (ED) and the Research and development Division (R and D) of Electricite de France are working together in the field of Instrumentation and Control (I and C) to improve its engineering method and tools. This method and these tools are defined on the basis of the experience feedback from the N4 nuclear power plant generation and the current information technology, to improve engineering competitiveness and quality of control applications. We intend to decouple the I and C processing from the I and C Human Machine Interface (HMI), because methods and tools are different. In this paper, we only focus on method and tools for I and C processing. We define the I and C processing life cycle into three phases. The first phase is the specification of the control application processing, the product of which is called Functional Requirement Diagrams (FRDs). The second phase is the design of the I and C system. This phase is subdivided into two steps. The step 1 is the distribution of the FRDs into an I and C architecture. The step 2 is the allocation of resources of the I and C system, to support the distributed FRDs. The third phase is the implementation of the distributed FRDs into I and C equipment. The aim of the Engineering Division is to achieve formal FRDs, independent of I and C suppliers. This allows a large improvement for the quality of the specification and the dimensioning of the I and C system before calls for tenders. For the specification phase, studies are almost completed. For the design and the implementation phases, studies and experiments are in progress with European I and C system suppliers. As a conclusion, we present the interest of EDF for standards and especially IEC 1131 improvements. (author). 5 figs.
17. Controllability of partial differential equations governed by multiplicative controls
Khapalov, Alexander Y
2010-01-01
The goal of this monograph is to address the issue of the global controllability of partial differential equations in the context of multiplicative (or bilinear) controls, which enter the model equations as coefficients. The mathematical models we examine include the linear and nonlinear parabolic and hyperbolic PDE's, the Schrödinger equation, and coupled hybrid nonlinear distributed parameter systems modeling the swimming phenomenon. The book offers a new, high-quality and intrinsically nonlinear methodology to approach the aforementioned highly nonlinear controllability problems.
18. Multiple Model Approaches to Modelling and Control,
on the ease with which prior knowledge can be incorporated. It is interesting to note that researchers in Control Theory, Neural Networks,Statistics, Artificial Intelligence and Fuzzy Logic have more or less independently developed very similar modelling methods, calling them Local ModelNetworks, Operating......, and allows direct incorporation of high-level and qualitative plant knowledge into themodel. These advantages have proven to be very appealing for industrial applications, and the practical, intuitively appealing nature of the framework isdemonstrated in chapters describing applications of local methods...... to problems in the process industries, biomedical applications and autonomoussystems. The successful application of the ideas to demanding problems is already encouraging, but creative development of the basic framework isneeded to better allow the integration of human knowledge with automated learning...
19. Multiple sclerosis in the Faroe Islands. 7. Results of a case control questionnaire with multiple controls
Kurtzke, J F; Hyllested, K; Arbuckle, J D
1997-01-01
Detailed questionnaires were completed in 1978-79 by 23 of the 28 then known resident Faroese multiple sclerosis (MS) patients and 127 controls. These controls were divided into 69 Group A (patient sibs and other relatives), 37 Group B (matched neighbor controls, their spouses and sibs, plus...... facilities, and nature of house construction or heating. Detailed dietary histories, available for half the subjects, revealed no differences, cases versus controls, for four age periods between age 0 and 30 years, and for 16 specified foodstuffs. Animal exposures showed overall no consistent differences...
20. Robust Tests for Additive Gene-Environment Interaction in Case-Control Studies Using Gene-Environment Independence
Liu, Gang; Lee, Seunggeun; Lee, Alice W
2018-01-01
test with case-control data. Our simulation studies suggest that the EB approach uses the gene-environment independence assumption in a data-adaptive way and provides power gain compared to the standard logistic regression analysis and better control of Type I error when compared to the analysis......There have been recent proposals advocating the use of additive gene-environment interaction instead of the widely used multiplicative scale, as a more relevant public health measure. Using gene-environment independence enhances the power for testing multiplicative interaction in case......-control studies. However, under departure from this assumption, substantial bias in the estimates and inflated Type I error in the corresponding tests can occur. This paper extends the empirical Bayes (EB) approach previously developed for multiplicative interaction that trades off between bias and efficiency...
1. Generalised model-independent characterisation of strong gravitational lenses. II. Transformation matrix between multiple images
Wagner, J.; Tessore, N.
2018-05-01
We determine the transformation matrix that maps multiple images with identifiable resolved features onto one another and that is based on a Taylor-expanded lensing potential in the vicinity of a point on the critical curve within our model-independent lens characterisation approach. From the transformation matrix, the same information about the properties of the critical curve at fold and cusp points can be derived as we previously found when using the quadrupole moment of the individual images as observables. In addition, we read off the relative parities between the images, so that the parity of all images is determined when one is known. We compare all retrievable ratios of potential derivatives to the actual values and to those obtained by using the quadrupole moment as observable for two- and three-image configurations generated by a galaxy-cluster scale singular isothermal ellipse. We conclude that using the quadrupole moments as observables, the properties of the critical curve are retrieved to a higher accuracy at the cusp points and to a lower accuracy at the fold points; the ratios of second-order potential derivatives are retrieved to comparable accuracy. We also show that the approach using ratios of convergences and reduced shear components is equivalent to ours in the vicinity of the critical curve, but yields more accurate results and is more robust because it does not require a special coordinate system as the approach using potential derivatives does. The transformation matrix is determined by mapping manually assigned reference points in the multiple images onto one another. If the assignment of the reference points is subject to measurement uncertainties under the influence of noise, we find that the confidence intervals of the lens parameters can be as large as the values themselves when the uncertainties are larger than one pixel. In addition, observed multiple images with resolved features are more extended than unresolved ones, so that
2. Proton pump inhibitors induce a caspase-independent antitumor effect against human multiple myeloma.
Canitano, Andrea; Iessi, Elisabetta; Spugnini, Enrico Pierluigi; Federici, Cristina; Fais, Stefano
2016-07-01
Multiple Myeloma (MM) is the second most common hematological malignancy and is responsive to a limited number of drugs. Unfortunately, to date, despite the introduction of novel drugs, no relevant increase in survival rates has been obtained. Proton pump inhibitors (PPIs) have been shown to have significant antitumor action as single agents as well as in combination with chemotherapy. This study investigates the potential anti-tumor effectiveness of two PPIs, Lansoprazole and Omeprazole, against human MM cells. We found that Lansoprazole exerts straightforward efficacy against myeloma cells, even at suboptimal concentrations (50 µM), while Omeprazole has limited cytotoxic action. The Lansoprazole anti-MM effect was mostly mediated by a caspase-independent apoptotic-like cytotoxicity, with only a secondary anti-proliferative action. This study provides clear evidence supporting the use of Lansoprazole in the strive against MM with an efficacy proven much higher than current therapeutical approaches and without reported side effects. It is however conceivable that, consistent with the results obtained in other human tumors, Lansoprazole may well be combined with existing anti-myeloma therapies with the aim to improve the low level of efficacy of the current strategies. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
3. Multiple independent structural dynamic events in the evolution of snake mitochondrial genomes.
Qian, Lifu; Wang, Hui; Yan, Jie; Pan, Tao; Jiang, Shanqun; Rao, Dingqi; Zhang, Baowei
2018-05-10
Mitochondrial DNA sequences have long been used in phylogenetic studies. However, little attention has been paid to the changes in gene arrangement patterns in the snake's mitogenome. Here, we analyzed the complete mitogenome sequences and structures of 65 snake species from 14 families and examined their structural patterns, organization and evolution. Our purpose was to further investigate the evolutionary implications and possible rearrangement mechanisms of the mitogenome within snakes. In total, eleven types of mitochondrial gene arrangement patterns were detected (Type I, II, III, III-A, III-B, III-B1, III-C, III-D, III-E, III-F, III-G), with mitochondrial genome rearrangements being a major trend in snakes, especially in Alethinophidia. In snake mitogenomes, the rearrangements mainly involved three processes, gene loss, translocation and duplication. Within Scolecophidia, the O L was lost several times in Typhlopidae and Leptotyphlopidae, but persisted as a plesiomorphy in the Alethinophidia. Duplication of the control region and translocation of the tRNA Leu gene are two visible features in Alethinophidian mitochondrial genomes. Independently and stochastically, the duplication of pseudo-Pro (P*) emerged in seven different lineages of unequal size in three families, indicating that the presence of P* was a polytopic event in the mitogenome. The WANCY tRNA gene cluster and the control regions and their adjacent segments were hotspots for mitogenome rearrangement. Maintenance of duplicate control regions may be the source for snake mitogenome structural diversity.
4. Fine-scale mapping of 8q24 locus identifies multiple independent risk variants for breast cancer.
Shi, Jiajun; Zhang, Yanfeng; Zheng, Wei; Michailidou, Kyriaki; Ghoussaini, Maya; Bolla, Manjeet K; Wang, Qin; Dennis, Joe; Lush, Michael; Milne, Roger L; Shu, Xiao-Ou; Beesley, Jonathan; Kar, Siddhartha; Andrulis, Irene L; Anton-Culver, Hoda; Arndt, Volker; Beckmann, Matthias W; Zhao, Zhiguo; Guo, Xingyi; Benitez, Javier; Beeghly-Fadiel, Alicia; Blot, William; Bogdanova, Natalia V; Bojesen, Stig E; Brauch, Hiltrud; Brenner, Hermann; Brinton, Louise; Broeks, Annegien; Brüning, Thomas; Burwinkel, Barbara; Cai, Hui; Canisius, Sander; Chang-Claude, Jenny; Choi, Ji-Yeob; Couch, Fergus J; Cox, Angela; Cross, Simon S; Czene, Kamila; Darabi, Hatef; Devilee, Peter; Droit, Arnaud; Dork, Thilo; Fasching, Peter A; Fletcher, Olivia; Flyger, Henrik; Fostira, Florentia; Gaborieau, Valerie; García-Closas, Montserrat; Giles, Graham G; Guenel, Pascal; Haiman, Christopher A; Hamann, Ute; Hartman, Mikael; Miao, Hui; Hollestelle, Antoinette; Hopper, John L; Hsiung, Chia-Ni; Ito, Hidemi; Jakubowska, Anna; Johnson, Nichola; Torres, Diana; Kabisch, Maria; Kang, Daehee; Khan, Sofia; Knight, Julia A; Kosma, Veli-Matti; Lambrechts, Diether; Li, Jingmei; Lindblom, Annika; Lophatananon, Artitaya; Lubinski, Jan; Mannermaa, Arto; Manoukian, Siranoush; Le Marchand, Loic; Margolin, Sara; Marme, Frederik; Matsuo, Keitaro; McLean, Catriona; Meindl, Alfons; Muir, Kenneth; Neuhausen, Susan L; Nevanlinna, Heli; Nord, Silje; Børresen-Dale, Anne-Lise; Olson, Janet E; Orr, Nick; van den Ouweland, Ans M W; Peterlongo, Paolo; Putti, Thomas Choudary; Rudolph, Anja; Sangrajrang, Suleeporn; Sawyer, Elinor J; Schmidt, Marjanka K; Schmutzler, Rita K; Shen, Chen-Yang; Hou, Ming-Feng; Shrubsole, Matha J; Southey, Melissa C; Swerdlow, Anthony; Teo, Soo Hwang; Thienpont, Bernard; Toland, Amanda E; Tollenaar, Robert A E M; Tomlinson, Ian; Truong, Therese; Tseng, Chiu-Chen; Wen, Wanqing; Winqvist, Robert; Wu, Anna H; Yip, Cheng Har; Zamora, Pilar M; Zheng, Ying; Floris, Giuseppe; Cheng, Ching-Yu; Hooning, Maartje J; Martens, John W M; Seynaeve, Caroline; Kristensen, Vessela N; Hall, Per; Pharoah, Paul D P; Simard, Jacques; Chenevix-Trench, Georgia; Dunning, Alison M; Antoniou, Antonis C; Easton, Douglas F; Cai, Qiuyin; Long, Jirong
2016-09-15
Previous genome-wide association studies among women of European ancestry identified two independent breast cancer susceptibility loci represented by single nucleotide polymorphisms (SNPs) rs13281615 and rs11780156 at 8q24. A fine-mapping study across 2.06 Mb (chr8:127,561,724-129,624,067, hg19) in 55,540 breast cancer cases and 51,168 controls within the Breast Cancer Association Consortium was conducted. Three additional independent association signals in women of European ancestry, represented by rs35961416 (OR = 0.95, 95% CI = 0.93-0.97, conditional p = 5.8 × 10(-6) ), rs7815245 (OR = 0.94, 95% CI = 0.91-0.96, conditional p = 1.1 × 10(-6) ) and rs2033101 (OR = 1.05, 95% CI = 1.02-1.07, conditional p = 1.1 × 10(-4) ) were found. Integrative analysis using functional genomic data from the Roadmap Epigenomics, the Encyclopedia of DNA Elements project, the Cancer Genome Atlas and other public resources implied that SNPs rs7815245 in Signal 3, and rs1121948 in Signal 5 (in linkage disequilibrium with rs11780156, r(2) = 0.77), were putatively functional variants for two of the five independent association signals. The results highlighted multiple 8q24 variants associated with breast cancer susceptibility in women of European ancestry. © 2016 UICC.
5. Hydraulic engine valve actuation system including independent feedback control
Marriott, Craig D
2013-06-04
A hydraulic valve actuation assembly may include a housing, a piston, a supply control valve, a closing control valve, and an opening control valve. The housing may define a first fluid chamber, a second fluid chamber, and a third fluid chamber. The piston may be axially secured to an engine valve and located within the first, second and third fluid chambers. The supply control valve may control a hydraulic fluid supply to the piston. The closing control valve may be located between the supply control valve and the second fluid chamber and may control fluid flow from the second fluid chamber to the supply control valve. The opening control valve may be located between the supply control valve and the second fluid chamber and may control fluid flow from the supply control valve to the second fluid chamber.
6. The relationship between multiple joint flexibility and functional performance in independent and physically active elderly women
Maria Joana de Carvalho
2007-09-01
Full Text Available Multi-joint flexibility assessment seems to be more appropriate for analyzing the association between fl exibility and functional fitness, but there is a lack of studies to confi rm this possibility in elderly people. The present study investigated the relationship between a multiple joint fl exibility assessment and the functional performance of 30 independent and physically active elderly women (age=68±1yr. Flexibility was assessed using the Chair Sit-and-Reach Test (CSRT. Functional performance was tested by a combination of three tasks: a Step Length (SL; b Time to Put on Sneakers (TPS; c Climbing Stairs (CS. The association between fl exibility and functional performance was tested by both simple and multiple correlation techniques. Pearson’s correlation was signifi cant for TPS (r = -.37; p ABSTRACT
7. A Method of Calculating Functional Independence Measure at Discharge from Functional Independence Measure Effectiveness Predicted by Multiple Regression Analysis Has a High Degree of Predictive Accuracy.
Tokunaga, Makoto; Watanabe, Susumu; Sonoda, Shigeru
2017-09-01
Multiple linear regression analysis is often used to predict the outcome of stroke rehabilitation. However, the predictive accuracy may not be satisfactory. The objective of this study was to elucidate the predictive accuracy of a method of calculating motor Functional Independence Measure (mFIM) at discharge from mFIM effectiveness predicted by multiple regression analysis. The subjects were 505 patients with stroke who were hospitalized in a convalescent rehabilitation hospital. The formula "mFIM at discharge = mFIM effectiveness × (91 points - mFIM at admission) + mFIM at admission" was used. By including the predicted mFIM effectiveness obtained through multiple regression analysis in this formula, we obtained the predicted mFIM at discharge (A). We also used multiple regression analysis to directly predict mFIM at discharge (B). The correlation between the predicted and the measured values of mFIM at discharge was compared between A and B. The correlation coefficients were .916 for A and .878 for B. Calculating mFIM at discharge from mFIM effectiveness predicted by multiple regression analysis had a higher degree of predictive accuracy of mFIM at discharge than that directly predicted. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.
8. Diffraction-Induced Bidimensional Talbot Self-Imaging with Full Independent Period Control
Guillet de Chatellus, Hugues; Romero Cortés, Luis; Deville, Antonin; Seghilani, Mohamed; Azaña, José
2017-03-01
We predict, formulate, and observe experimentally a generalized version of the Talbot effect that allows one to create diffraction-induced self-images of a periodic two-dimensional (2D) waveform with arbitrary control of the image spatial periods. Through the proposed scheme, the periods of the output self-image are multiples of the input ones by any desired integer or fractional factor, and they can be controlled independently across each of the two wave dimensions. The concept involves conditioning the phase profile of the input periodic wave before free-space diffraction. The wave energy is fundamentally preserved through the self-imaging process, enabling, for instance, the possibility of the passive amplification of the periodic patterns in the wave by a purely diffractive effect, without the use of any active gain.
9. Relative null controllability of linear systems with multiple delays in ...
varying multiple delays in state and control are developed. If the uncontrolled system is uniformly asymptotically stable, and if the linear system is controllable, then the linear system is null controllable. Journal of the Nigerian Association of ...
10. Optimization of Inventories for Multiple Companies by Fuzzy Control Method
Kawase, Koichi; Konishi, Masami; Imai, Jun
2008-01-01
In this research, Fuzzy control theory is applied to the inventory control of the supply chain between multiple companies. The proposed control method deals with the amountof inventories expressing supply chain between multiple companies. Referring past demand and tardiness, inventory amounts of raw materials are determined by Fuzzy inference. The method that an appropriate inventory control becomes possible optimizing fuzzy control gain by using SA method for Fuzzy control. The variation of ...
11. Fine-scale mapping of 8q24 locus identifies multiple independent risk variants for breast cancer
Shi, Jiajun; Zhang, Yanfeng; Zheng, Wei
2016-01-01
public resources implied that SNPs rs7815245 in Signal 3, and rs1121948 in Signal 5 (in linkage disequilibrium with rs11780156, r(2) = 0.77), were putatively functional variants for two of the five independent association signals. The results highlighted multiple 8q24 variants associated with breast...
12. AS3MT-mediated tolerance to arsenic evolved by multiple independent horizontal gene transfers from bacteria to eukaryotes
Palmgren, Michael; Engström, Karin; Hallström, Björn M.
2017-01-01
the evolutionary origin of AS3MT and assessed the ability of different genotypes to produce methylated arsenic metabolites. Phylogenetic analysis suggests that multiple, independent horizontal gene transfers between different bacteria, and from bacteria to eukaryotes, increased tolerance to environmental arsenic...
13. Multiple independent variants at the TERT locus are associated with telomere length and risks of breast and ovarian cancer.
Bojesen, Stig E; Pooley, Karen A; Johnatty, Sharon E; Beesley, Jonathan; Michailidou, Kyriaki; Tyrer, Jonathan P; Edwards, Stacey L; Pickett, Hilda A; Shen, Howard C; Smart, Chanel E; Hillman, Kristine M; Mai, Phuong L; Lawrenson, Kate; Stutz, Michael D; Lu, Yi; Karevan, Rod; Woods, Nicholas; Johnston, Rebecca L; French, Juliet D; Chen, Xiaoqing; Weischer, Maren; Nielsen, Sune F; Maranian, Melanie J; Ghoussaini, Maya; Ahmed, Shahana; Baynes, Caroline; Bolla, Manjeet K; Wang, Qin; Dennis, Joe; McGuffog, Lesley; Barrowdale, Daniel; Lee, Andrew; Healey, Sue; Lush, Michael; Tessier, Daniel C; Vincent, Daniel; Bacot, Françis; Vergote, Ignace; Lambrechts, Sandrina; Despierre, Evelyn; Risch, Harvey A; González-Neira, Anna; Rossing, Mary Anne; Pita, Guillermo; Doherty, Jennifer A; Alvarez, Nuria; Larson, Melissa C; Fridley, Brooke L; Schoof, Nils; Chang-Claude, Jenny; Cicek, Mine S; Peto, Julian; Kalli, Kimberly R; Broeks, Annegien; Armasu, Sebastian M; Schmidt, Marjanka K; Braaf, Linde M; Winterhoff, Boris; Nevanlinna, Heli; Konecny, Gottfried E; Lambrechts, Diether; Rogmann, Lisa; Guénel, Pascal; Teoman, Attila; Milne, Roger L; Garcia, Joaquin J; Cox, Angela; Shridhar, Vijayalakshmi; Burwinkel, Barbara; Marme, Frederik; Hein, Rebecca; Sawyer, Elinor J; Haiman, Christopher A; Wang-Gohrke, Shan; Andrulis, Irene L; Moysich, Kirsten B; Hopper, John L; Odunsi, Kunle; Lindblom, Annika; Giles, Graham G; Brenner, Hermann; Simard, Jacques; Lurie, Galina; Fasching, Peter A; Carney, Michael E; Radice, Paolo; Wilkens, Lynne R; Swerdlow, Anthony; Goodman, Marc T; Brauch, Hiltrud; Garcia-Closas, Montserrat; Hillemanns, Peter; Winqvist, Robert; Dürst, Matthias; Devilee, Peter; Runnebaum, Ingo; Jakubowska, Anna; Lubinski, Jan; Mannermaa, Arto; Butzow, Ralf; Bogdanova, Natalia V; Dörk, Thilo; Pelttari, Liisa M; Zheng, Wei; Leminen, Arto; Anton-Culver, Hoda; Bunker, Clareann H; Kristensen, Vessela; Ness, Roberta B; Muir, Kenneth; Edwards, Robert; Meindl, Alfons; Heitz, Florian; Matsuo, Keitaro; du Bois, Andreas; Wu, Anna H; Harter, Philipp; Teo, Soo-Hwang; Schwaab, Ira; Shu, Xiao-Ou; Blot, William; Hosono, Satoyo; Kang, Daehee; Nakanishi, Toru; Hartman, Mikael; Yatabe, Yasushi; Hamann, Ute; Karlan, Beth Y; Sangrajrang, Suleeporn; Kjaer, Susanne Krüger; Gaborieau, Valerie; Jensen, Allan; Eccles, Diana; Høgdall, Estrid; Shen, Chen-Yang; Brown, Judith; Woo, Yin Ling; Shah, Mitul; Azmi, Mat Adenan Noor; Luben, Robert; Omar, Siti Zawiah; Czene, Kamila; Vierkant, Robert A; Nordestgaard, Børge G; Flyger, Henrik; Vachon, Celine; Olson, Janet E; Wang, Xianshu; Levine, Douglas A; Rudolph, Anja; Weber, Rachel Palmieri; Flesch-Janys, Dieter; Iversen, Edwin; Nickels, Stefan; Schildkraut, Joellen M; Silva, Isabel Dos Santos; Cramer, Daniel W; Gibson, Lorna; Terry, Kathryn L; Fletcher, Olivia; Vitonis, Allison F; van der Schoot, C Ellen; Poole, Elizabeth M; Hogervorst, Frans B L; Tworoger, Shelley S; Liu, Jianjun; Bandera, Elisa V; Li, Jingmei; Olson, Sara H; Humphreys, Keith; Orlow, Irene; Blomqvist, Carl; Rodriguez-Rodriguez, Lorna; Aittomäki, Kristiina; Salvesen, Helga B; Muranen, Taru A; Wik, Elisabeth; Brouwers, Barbara; Krakstad, Camilla; Wauters, Els; Halle, Mari K; Wildiers, Hans; Kiemeney, Lambertus A; Mulot, Claire; Aben, Katja K; Laurent-Puig, Pierre; Altena, Anne Mvan; Truong, Thérèse; Massuger, Leon F A G; Benitez, Javier; Pejovic, Tanja; Perez, Jose Ignacio Arias; Hoatlin, Maureen; Zamora, M Pilar; Cook, Linda S; Balasubramanian, Sabapathy P; Kelemen, Linda E; Schneeweiss, Andreas; Le, Nhu D; Sohn, Christof; Brooks-Wilson, Angela; Tomlinson, Ian; Kerin, Michael J; Miller, Nicola; Cybulski, Cezary; Henderson, Brian E; Menkiszak, Janusz; Schumacher, Fredrick; Wentzensen, Nicolas; Le Marchand, Loic; Yang, Hannah P; Mulligan, Anna Marie; Glendon, Gord; Engelholm, Svend Aage; Knight, Julia A; Høgdall, Claus K; Apicella, Carmel; Gore, Martin; Tsimiklis, Helen; Song, Honglin; Southey, Melissa C; Jager, Agnes; den Ouweland, Ans M Wvan; Brown, Robert; Martens, John W M; Flanagan, James M; Kriege, Mieke; Paul, James; Margolin, Sara; Siddiqui, Nadeem; Severi, Gianluca; Whittemore, Alice S; Baglietto, Laura; McGuire, Valerie; Stegmaier, Christa; Sieh, Weiva; Müller, Heiko; Arndt, Volker; Labrèche, France; Gao, Yu-Tang; Goldberg, Mark S; Yang, Gong; Dumont, Martine; McLaughlin, John R; Hartmann, Arndt; Ekici, Arif B; Beckmann, Matthias W; Phelan, Catherine M; Lux, Michael P; Permuth-Wey, Jenny; Peissel, Bernard; Sellers, Thomas A; Ficarazzi, Filomena; Barile, Monica; Ziogas, Argyrios; Ashworth, Alan; Gentry-Maharaj, Aleksandra; Jones, Michael; Ramus, Susan J; Orr, Nick; Menon, Usha; Pearce, Celeste L; Brüning, Thomas; Pike, Malcolm C; Ko, Yon-Dschun; Lissowska, Jolanta; Figueroa, Jonine; Kupryjanczyk, Jolanta; Chanock, Stephen J; Dansonka-Mieszkowska, Agnieszka; Jukkola-Vuorinen, Arja; Rzepecka, Iwona K; Pylkäs, Katri; Bidzinski, Mariusz; Kauppila, Saila; Hollestelle, Antoinette; Seynaeve, Caroline; Tollenaar, Rob A E M; Durda, Katarzyna; Jaworska, Katarzyna; Hartikainen, Jaana M; Kosma, Veli-Matti; Kataja, Vesa; Antonenkova, Natalia N; Long, Jirong; Shrubsole, Martha; Deming-Halverson, Sandra; Lophatananon, Artitaya; Siriwanarangsan, Pornthep; Stewart-Brown, Sarah; Ditsch, Nina; Lichtner, Peter; Schmutzler, Rita K; Ito, Hidemi; Iwata, Hiroji; Tajima, Kazuo; Tseng, Chiu-Chen; Stram, Daniel O; van den Berg, David; Yip, Cheng Har; Ikram, M Kamran; Teh, Yew-Ching; Cai, Hui; Lu, Wei; Signorello, Lisa B; Cai, Qiuyin; Noh, Dong-Young; Yoo, Keun-Young; Miao, Hui; Iau, Philip Tsau-Choong; Teo, Yik Ying; McKay, James; Shapiro, Charles; Ademuyiwa, Foluso; Fountzilas, George; Hsiung, Chia-Ni; Yu, Jyh-Cherng; Hou, Ming-Feng; Healey, Catherine S; Luccarini, Craig; Peock, Susan; Stoppa-Lyonnet, Dominique; Peterlongo, Paolo; Rebbeck, Timothy R; Piedmonte, Marion; Singer, Christian F; Friedman, Eitan; Thomassen, Mads; Offit, Kenneth; Hansen, Thomas V O; Neuhausen, Susan L; Szabo, Csilla I; Blanco, Ignacio; Garber, Judy; Narod, Steven A; Weitzel, Jeffrey N; Montagna, Marco; Olah, Edith; Godwin, Andrew K; Yannoukakos, Drakoulis; Goldgar, David E; Caldes, Trinidad; Imyanitov, Evgeny N; Tihomirova, Laima; Arun, Banu K; Campbell, Ian; Mensenkamp, Arjen R; van Asperen, Christi J; van Roozendaal, Kees E P; Meijers-Heijboer, Hanne; Collée, J Margriet; Oosterwijk, Jan C; Hooning, Maartje J; Rookus, Matti A; van der Luijt, Rob B; Os, Theo A Mvan; Evans, D Gareth; Frost, Debra; Fineberg, Elena; Barwell, Julian; Walker, Lisa; Kennedy, M John; Platte, Radka; Davidson, Rosemarie; Ellis, Steve D; Cole, Trevor; Bressac-de Paillerets, Brigitte; Buecher, Bruno; Damiola, Francesca; Faivre, Laurence; Frenay, Marc; Sinilnikova, Olga M; Caron, Olivier; Giraud, Sophie; Mazoyer, Sylvie; Bonadona, Valérie; Caux-Moncoutier, Virginie; Toloczko-Grabarek, Aleksandra; Gronwald, Jacek; Byrski, Tomasz; Spurdle, Amanda B; Bonanni, Bernardo; Zaffaroni, Daniela; Giannini, Giuseppe; Bernard, Loris; Dolcetti, Riccardo; Manoukian, Siranoush; Arnold, Norbert; Engel, Christoph; Deissler, Helmut; Rhiem, Kerstin; Niederacher, Dieter; Plendl, Hansjoerg; Sutter, Christian; Wappenschmidt, Barbara; Borg, Ake; Melin, Beatrice; Rantala, Johanna; Soller, Maria; Nathanson, Katherine L; Domchek, Susan M; Rodriguez, Gustavo C; Salani, Ritu; Kaulich, Daphne Gschwantler; Tea, Muy-Kheng; Paluch, Shani Shimon; Laitman, Yael; Skytte, Anne-Bine; Kruse, Torben A; Jensen, Uffe Birk; Robson, Mark; Gerdes, Anne-Marie; Ejlertsen, Bent; Foretova, Lenka; Savage, Sharon A; Lester, Jenny; Soucy, Penny; Kuchenbaecker, Karoline B; Olswold, Curtis; Cunningham, Julie M; Slager, Susan; Pankratz, Vernon S; Dicks, Ed; Lakhani, Sunil R; Couch, Fergus J; Hall, Per; Monteiro, Alvaro N A; Gayther, Simon A; Pharoah, Paul D P; Reddel, Roger R; Goode, Ellen L; Greene, Mark H; Easton, Douglas F; Berchuck, Andrew; Antoniou, Antonis C; Chenevix-Trench, Georgia; Dunning, Alison M
2013-04-01
TERT-locus SNPs and leukocyte telomere measures are reportedly associated with risks of multiple cancers. Using the Illumina custom genotyping array iCOGs, we analyzed ∼480 SNPs at the TERT locus in breast (n = 103,991), ovarian (n = 39,774) and BRCA1 mutation carrier (n = 11,705) cancer cases and controls. Leukocyte telomere measurements were also available for 53,724 participants. Most associations cluster into three independent peaks. The minor allele at the peak 1 SNP rs2736108 associates with longer telomeres (P = 5.8 × 10(-7)), lower risks for estrogen receptor (ER)-negative (P = 1.0 × 10(-8)) and BRCA1 mutation carrier (P = 1.1 × 10(-5)) breast cancers and altered promoter assay signal. The minor allele at the peak 2 SNP rs7705526 associates with longer telomeres (P = 2.3 × 10(-14)), higher risk of low-malignant-potential ovarian cancer (P = 1.3 × 10(-15)) and greater promoter activity. The minor alleles at the peak 3 SNPs rs10069690 and rs2242652 increase ER-negative (P = 1.2 × 10(-12)) and BRCA1 mutation carrier (P = 1.6 × 10(-14)) breast and invasive ovarian (P = 1.3 × 10(-11)) cancer risks but not via altered telomere length. The cancer risk alleles of rs2242652 and rs10069690, respectively, increase silencing and generate a truncated TERT splice variant.
14. Multiple independent variants at the TERT locus are associated with telomere length and risks of breast and ovarian cancer
Bojesen, Stig E; Pooley, Karen A; Johnatty, Sharon E; Beesley, Jonathan; Michailidou, Kyriaki; Tyrer, Jonathan P; Edwards, Stacey L; Pickett, Hilda A; Shen, Howard C; Smart, Chanel E; Hillman, Kristine M; Mai, Phuong L; Lawrenson, Kate; Stutz, Michael D; Lu, Yi; Karevan, Rod; Woods, Nicholas; Johnston, Rebecca L; French, Juliet D; Chen, Xiaoqing; Weischer, Maren; Nielsen, Sune F; Maranian, Melanie J; Ghoussaini, Maya; Ahmed, Shahana; Baynes, Caroline; Bolla, Manjeet K; Wang, Qin; Dennis, Joe; McGuffog, Lesley; Barrowdale, Daniel; Lee, Andrew; Healey, Sue; Lush, Michael; Tessier, Daniel C; Vincent, Daniel; Bacot, Françis; Vergote, Ignace; Lambrechts, Sandrina; Despierre, Evelyn; Risch, Harvey A; González-Neira, Anna; Rossing, Mary Anne; Pita, Guillermo; Doherty, Jennifer A; Álvarez, Nuria; Larson, Melissa C; Fridley, Brooke L; Schoof, Nils; Chang-Claude, Jenny; Cicek, Mine S; Peto, Julian; Kalli, Kimberly R; Broeks, Annegien; Armasu, Sebastian M; Schmidt, Marjanka K; Braaf, Linde M; Winterhoff, Boris; Nevanlinna, Heli; Konecny, Gottfried E; Lambrechts, Diether; Rogmann, Lisa; Guénel, Pascal; Teoman, Attila; Milne, Roger L; Garcia, Joaquin J; Cox, Angela; Shridhar, Vijayalakshmi; Burwinkel, Barbara; Marme, Frederik; Hein, Rebecca; Sawyer, Elinor J; Haiman, Christopher A; Wang-Gohrke, Shan; Andrulis, Irene L; Moysich, Kirsten B; Hopper, John L; Odunsi, Kunle; Lindblom, Annika; Giles, Graham G; Brenner, Hermann; Simard, Jacques; Lurie, Galina; Fasching, Peter A; Carney, Michael E; Radice, Paolo; Wilkens, Lynne R; Swerdlow, Anthony; Goodman, Marc T; Brauch, Hiltrud; García-Closas, Montserrat; Hillemanns, Peter; Winqvist, Robert; Dürst, Matthias; Devilee, Peter; Runnebaum, Ingo; Jakubowska, Anna; Lubinski, Jan; Mannermaa, Arto; Butzow, Ralf; Bogdanova, Natalia V; Dörk, Thilo; Pelttari, Liisa M; Zheng, Wei; Leminen, Arto; Anton-Culver, Hoda; Bunker, Clareann H; Kristensen, Vessela; Ness, Roberta B; Muir, Kenneth; Edwards, Robert; Meindl, Alfons; Heitz, Florian; Matsuo, Keitaro; du Bois, Andreas; Wu, Anna H; Harter, Philipp; Teo, Soo-Hwang; Schwaab, Ira; Shu, Xiao-Ou; Blot, William; Hosono, Satoyo; Kang, Daehee; Nakanishi, Toru; Hartman, Mikael; Yatabe, Yasushi; Hamann, Ute; Karlan, Beth Y; Sangrajrang, Suleeporn; Kjaer, Susanne Krüger; Gaborieau, Valerie; Jensen, Allan; Eccles, Diana; Høgdall, Estrid; Shen, Chen-Yang; Brown, Judith; Woo, Yin Ling; Shah, Mitul; Azmi, Mat Adenan Noor; Luben, Robert; Omar, Siti Zawiah; Czene, Kamila; Vierkant, Robert A; Nordestgaard, Børge G; Flyger, Henrik; Vachon, Celine; Olson, Janet E; Wang, Xianshu; Levine, Douglas A; Rudolph, Anja; Weber, Rachel Palmieri; Flesch-Janys, Dieter; Iversen, Edwin; Nickels, Stefan; Schildkraut, Joellen M; Silva, Isabel Dos Santos; Cramer, Daniel W; Gibson, Lorna; Terry, Kathryn L; Fletcher, Olivia; Vitonis, Allison F; van der Schoot, C Ellen; Poole, Elizabeth M; Hogervorst, Frans B L; Tworoger, Shelley S; Liu, Jianjun; Bandera, Elisa V; Li, Jingmei; Olson, Sara H; Humphreys, Keith; Orlow, Irene; Blomqvist, Carl; Rodriguez-Rodriguez, Lorna; Aittomäki, Kristiina; Salvesen, Helga B; Muranen, Taru A; Wik, Elisabeth; Brouwers, Barbara; Krakstad, Camilla; Wauters, Els; Halle, Mari K; Wildiers, Hans; Kiemeney, Lambertus A; Mulot, Claire; Aben, Katja K; Laurent-Puig, Pierre; van Altena, Anne M; Truong, Thérèse; Massuger, Leon F A G; Benitez, Javier; Pejovic, Tanja; Perez, Jose Ignacio Arias; Hoatlin, Maureen; Zamora, M Pilar; Cook, Linda S; Balasubramanian, Sabapathy P; Kelemen, Linda E; Schneeweiss, Andreas; Le, Nhu D; Sohn, Christof; Brooks-Wilson, Angela; Tomlinson, Ian; Kerin, Michael J; Miller, Nicola; Cybulski, Cezary; Henderson, Brian E; Menkiszak, Janusz; Schumacher, Fredrick; Wentzensen, Nicolas; Marchand, Loic Le; Yang, Hannah P; Mulligan, Anna Marie; Glendon, Gord; Engelholm, Svend Aage; Knight, Julia A; Høgdall, Claus K; Apicella, Carmel; Gore, Martin; Tsimiklis, Helen; Song, Honglin; Southey, Melissa C; Jager, Agnes; van den Ouweland, Ans M W; Brown, Robert; Martens, John W M; Flanagan, James M; Kriege, Mieke; Paul, James; Margolin, Sara; Siddiqui, Nadeem; Severi, Gianluca; Whittemore, Alice S; Baglietto, Laura; McGuire, Valerie; Stegmaier, Christa; Sieh, Weiva; Müller, Heiko; Arndt, Volker; Labrèche, France; Gao, Yu-Tang; Goldberg, Mark S; Yang, Gong; Dumont, Martine; McLaughlin, John R; Hartmann, Arndt; Ekici, Arif B; Beckmann, Matthias W; Phelan, Catherine M; Lux, Michael P; Permuth-Wey, Jenny; Peissel, Bernard; Sellers, Thomas A; Ficarazzi, Filomena; Barile, Monica; Ziogas, Argyrios; Ashworth, Alan; Gentry-Maharaj, Aleksandra; Jones, Michael; Ramus, Susan J; Orr, Nick; Menon, Usha; Pearce, Celeste L; Brüning, Thomas; Pike, Malcolm C; Ko, Yon-Dschun; Lissowska, Jolanta; Figueroa, Jonine; Kupryjanczyk, Jolanta; Chanock, Stephen J; Dansonka-Mieszkowska, Agnieszka; Jukkola-Vuorinen, Arja; Rzepecka, Iwona K; Pylkäs, Katri; Bidzinski, Mariusz; Kauppila, Saila; Hollestelle, Antoinette; Seynaeve, Caroline; Tollenaar, Rob A E M; Durda, Katarzyna; Jaworska, Katarzyna; Hartikainen, Jaana M; Kosma, Veli-Matti; Kataja, Vesa; Antonenkova, Natalia N; Long, Jirong; Shrubsole, Martha; Deming-Halverson, Sandra; Lophatananon, Artitaya; Siriwanarangsan, Pornthep; Stewart-Brown, Sarah; Ditsch, Nina; Lichtner, Peter; Schmutzler, Rita K; Ito, Hidemi; Iwata, Hiroji; Tajima, Kazuo; Tseng, Chiu-Chen; Stram, Daniel O; van den Berg, David; Yip, Cheng Har; Ikram, M Kamran; Teh, Yew-Ching; Cai, Hui; Lu, Wei; Signorello, Lisa B; Cai, Qiuyin; Noh, Dong-Young; Yoo, Keun-Young; Miao, Hui; Iau, Philip Tsau-Choong; Teo, Yik Ying; McKay, James; Shapiro, Charles; Ademuyiwa, Foluso; Fountzilas, George; Hsiung, Chia-Ni; Yu, Jyh-Cherng; Hou, Ming-Feng; Healey, Catherine S; Luccarini, Craig; Peock, Susan; Stoppa-Lyonnet, Dominique; Peterlongo, Paolo; Rebbeck, Timothy R; Piedmonte, Marion; Singer, Christian F; Friedman, Eitan; Thomassen, Mads; Offit, Kenneth; Hansen, Thomas V O; Neuhausen, Susan L; Szabo, Csilla I; Blanco, Ignacio; Garber, Judy; Narod, Steven A; Weitzel, Jeffrey N; Montagna, Marco; Olah, Edith; Godwin, Andrew K; Yannoukakos, Drakoulis; Goldgar, David E; Caldes, Trinidad; Imyanitov, Evgeny N; Tihomirova, Laima; Arun, Banu K; Campbell, Ian; Mensenkamp, Arjen R; van Asperen, Christi J; van Roozendaal, Kees E P; Meijers-Heijboer, Hanne; Collée, J Margriet; Oosterwijk, Jan C; Hooning, Maartje J; Rookus, Matti A; van der Luijt, Rob B; van Os, Theo A M; Evans, D Gareth; Frost, Debra; Fineberg, Elena; Barwell, Julian; Walker, Lisa; Kennedy, M John; Platte, Radka; Davidson, Rosemarie; Ellis, Steve D; Cole, Trevor; Paillerets, Brigitte Bressac-de; Buecher, Bruno; Damiola, Francesca; Faivre, Laurence; Frenay, Marc; Sinilnikova, Olga M; Caron, Olivier; Giraud, Sophie; Mazoyer, Sylvie; Bonadona, Valérie; Caux-Moncoutier, Virginie; Toloczko-Grabarek, Aleksandra; Gronwald, Jacek; Byrski, Tomasz; Spurdle, Amanda B; Bonanni, Bernardo; Zaffaroni, Daniela; Giannini, Giuseppe; Bernard, Loris; Dolcetti, Riccardo; Manoukian, Siranoush; Arnold, Norbert; Engel, Christoph; Deissler, Helmut; Rhiem, Kerstin; Niederacher, Dieter; Plendl, Hansjoerg; Sutter, Christian; Wappenschmidt, Barbara; Borg, Åke; Melin, Beatrice; Rantala, Johanna; Soller, Maria; Nathanson, Katherine L; Domchek, Susan M; Rodriguez, Gustavo C; Salani, Ritu; Kaulich, Daphne Gschwantler; Tea, Muy-Kheng; Paluch, Shani Shimon; Laitman, Yael; Skytte, Anne-Bine; Kruse, Torben A; Jensen, Uffe Birk; Robson, Mark; Gerdes, Anne-Marie; Ejlertsen, Bent; Foretova, Lenka; Savage, Sharon A; Lester, Jenny; Soucy, Penny; Kuchenbaecker, Karoline B; Olswold, Curtis; Cunningham, Julie M; Slager, Susan; Pankratz, Vernon S; Dicks, Ed; Lakhani, Sunil R; Couch, Fergus J; Hall, Per; Monteiro, Alvaro N A; Gayther, Simon A; Pharoah, Paul D P; Reddel, Roger R; Goode, Ellen L; Greene, Mark H; Easton, Douglas F; Berchuck, Andrew; Antoniou, Antonis C; Chenevix-Trench, Georgia; Dunning, Alison M
2013-01-01
TERT-locus single nucleotide polymorphisms (SNPs) and leucocyte telomere measures are reportedly associated with risks of multiple cancers. Using the iCOGs chip, we analysed ~480 TERT-locus SNPs in breast (n=103,991), ovarian (n=39,774) and BRCA1 mutation carrier (11,705) cancer cases and controls. 53,724 participants have leucocyte telomere measures. Most associations cluster into three independent peaks. Peak 1 SNP rs2736108 minor allele associates with longer telomeres (P=5.8×10−7), reduced estrogen receptor negative (ER-negative) (P=1.0×10−8) and BRCA1 mutation carrier (P=1.1×10−5) breast cancer risks, and altered promoter-assay signal. Peak 2 SNP rs7705526 minor allele associates with longer telomeres (P=2.3×10−14), increased low malignant potential ovarian cancer risk (P=1.3×10−15) and increased promoter activity. Peak 3 SNPs rs10069690 and rs2242652 minor alleles increase ER-negative (P=1.2×10−12) and BRCA1 mutation carrier (P=1.6×10−14) breast and invasive ovarian (P=1.3×10−11) cancer risks, but not via altered telomere length. The cancer-risk alleles of rs2242652 and rs10069690 respectively increase silencing and generate a truncated TERT splice-variant. PMID:23535731
15. Inventory control with multiple setup costs
Alp, O.; Huh, W.T.; Tan, T.
2014-01-01
We consider an infinite-horizon, periodic-review, single-item production/inventory system with random demand and backordering, where multiple setups are allowed in any period and a separate fixed cost is associated for each setup. Contrary to the majority of the literature on this topic, we do not
16. Characteristics Verification of an Independently Controllable Electromagnetic Spherical Motor
Shuhei Maeda
2014-06-01
Full Text Available We have been developing electromagnetic spherical actuators capable of three-degree-of-freedom rotation. However, these actuators require complex control to realize simultaneous triaxial drive, because rotation around one axis interferes with rotation around another. In this paper, we propose a new three-degree-of-freedom actuator where 3-axes rotation can be controlled easily. The basic structure and the operating principle of the actuator are described. Then the torque characteristics and the dynamic characteristics are computed by employing 3D-FEM and the effectiveness of this actuator is clarified. Finally, the experimental results using the prototype of the actuator are shown to verify the dynamic performance.
17. Notification: Controls Over Results Produced by EPA Independent Laboratories
Project #OPE-FY16-0022, April 5, 2016. The EPA OIG plans to begin preliminary research on controls that the EPA’s Office of Land and Emergency Management’s Contract Laboratory Program (CLP) has in place to detect or prevent fraud.
18. Comparison of Two Independent LIDAR-Based Pitch Control Designs
Dunne, F.; Schlipf, D.; Pao, L. Y.
2012-08-01
Two different lidar-based feedforward controllers have previously been designed for the NREL 5 MW wind turbine model under separate studies. Feedforward controller A uses a finite-impulse-response design, with 5 seconds of preview, and three rotating lidar measurements. Feedforward controller B uses a static-gain design, with the preview time defined by the pitch actuator dynamics, a simulation of a real nacelle-based scanning lidar system, and a lowpass filter defined by the lidar configuration. These controllers are now directly compared under the same lidar configuration, in terms of fatigue load reduction, rotor speed regulation, and power capture. The various differences in design choices are discussed and compared. We also compare frequency plots of individual pitch feedforward and collective pitch feedforward load reductions, and we see that individual pitch feedforward is effective mainly at the once-per-revolution and twice-per-revolution frequencies. We also explain how to determine the required preview time by breaking it down into separate parts, and we then compare it to the expected preview time available.
19. Only low frequency event-related EEG activity is compromised in multiple sclerosis: insights from an independent component clustering analysis.
Hanni Kiiski
Full Text Available Cognitive impairment (CI, often examined with neuropsychological tests such as the Paced Auditory Serial Addition Test (PASAT, affects approximately 65% of multiple sclerosis (MS patients. The P3b event-related potential (ERP, evoked when an infrequent target stimulus is presented, indexes cognitive function and is typically compared across subjects' scalp electroencephalography (EEG data. However, the clustering of independent components (ICs is superior to scalp-based EEG methods because it can accommodate the spatiotemporal overlap inherent in scalp EEG data. Event-related spectral perturbations (ERSPs; event-related mean power spectral changes and inter-trial coherence (ITCs; event-related consistency of spectral phase reveal a more comprehensive overview of EEG activity. Ninety-five subjects (56 MS patients, 39 controls completed visual and auditory two-stimulus P3b event-related potential tasks and the PASAT. MS patients were also divided into CI and non-CI groups (n = 18 in each based on PASAT scores. Data were recorded from 128-scalp EEG channels and 4 IC clusters in the visual, and 5 IC clusters in the auditory, modality were identified. In general, MS patients had significantly reduced ERSP theta power versus controls, and a similar pattern was observed for CI vs. non-CI MS patients. The ITC measures were also significantly different in the theta band for some clusters. The finding that MS patients had reduced P3b task-related theta power in both modalities is a reflection of compromised connectivity, likely due to demyelination, that may have disrupted early processes essential to P3b generation, such as orientating and signal detection. However, for posterior sources, MS patients had a greater decrease in alpha power, normally associated with enhanced cognitive function, which may reflect a compensatory mechanism in response to the compromised early cognitive processing.
20. Hierarchical Control for Multiple DC Microgrids Clusters
Shafiee, Qobad; Dragicevic, Tomislav; Vasquez, Juan Carlos
2014-01-01
This paper presents a distributed hierarchical control framework to ensure reliable operation of dc Microgrid (MG) clusters. In this hierarchy, primary control is used to regulate the common bus voltage inside each MG locally. An adaptive droop method is proposed for this level which determines...
1. "Capitalizing on Sport": Sport, Physical Education and Multiple Capitals in Scottish Independent Schools
Horne, John; Lingard, Bob; Weiner, Gaby; Forbes, Joan
2011-01-01
This paper draws on a research study into the existence and use of different forms of capital--including social, cultural and physical capital--in three independent schools in Scotland. We were interested in understanding how these forms of capital work to produce and reproduce "advantage" and "privilege". Analysis is framed by…
2. Pseudo-random Trees: Multiple Independent Sequence Generators for Parallel and Branching Computations
Halton, John H.
1989-09-01
A class of families of linear congruential pseudo-random sequences is defined, for which it is possible to branch at any event without changing the sequence of random numbers used in the original random walk and for which the sequences in different branches show properties analogous to mutual statistical independence. This is a hitherto unavailable, and computationally desirable, tool.
3. Bayesian evaluation of constrained hypotheses on variances of multiple independent groups
Böing-Messing, F.; van Assen, M.A.L.M.; Hofman, A.D.; Hoijtink, H.; Mulder, J.
2017-01-01
Research has shown that independent groups often differ not only in their means, but also in their variances. Comparing and testing variances is therefore of crucial importance to understand the effect of a grouping variable on an outcome variable. Researchers may have specific expectations
4. Radiological control of contractors' employees - an independent RPA's view
Ellis, J.O.; Webb, C.A.
1995-01-01
The changing structure of the nuclear industry in the UK is resulting in a significant increase in the number of contracting companies whose employees are engaged in work that would previously have been the sole responsibility of the workforce directly employed by the Site Licence holder. This trend is being given added impetus by the move towards contractorisation and privatisation of significant portions of the industry; for example, the UKAEA is, at the time of writing, divided into three separate organisations responsible for the work in Controlled Areas at several sites. This paper seeks to set out some of the potential and actual radiological problems encountered, together with some suggested solutions. (author)
5. Smart transactive energy framework in grid-connected multiple home microgrids under independent and coalition operations
Marzband, Mousa; Azarinejadian, Fatemeh; Savaghebi, Mehdi
2018-01-01
This paper presents a smart Transactive energy (TE) framework in which home microgrids (H-MGs) can collaborate with each other in a multiple H-MG system by forming coalitions for gaining competitiveness in the market. Profit allocation due to coalition between H-MGs is an important issue...... for ensuring the optimal use of installed resources in the whole multiple H-MG system. In addition, considering demand fluctuations, energy production based on renewable resources in the multiple H-MG can be accomplished by demand-side management strategies that try to establish mechanisms to allow...... for a flatter demand curve. In this regard, demand shifting potential can be tapped through shifting certain amounts of energy demand from some time periods to others with lower expected demand, typically to match price values and to ensure that existing generation will be economically sufficient. It is also...
6. Multiple Property Cross Direction Control of Paper Machines
Markku Ohenoja
2011-07-01
Full Text Available Cross direction (CD control in sheet-forming process forms a challenging problem with high dimensions. Accounting the interactions between different properties and actuators, the dimensionality increases further and also computational issues arise. We present a multiple property controller feasible to be used especially with imaging measurements that provide high sampling frequency and therefore enable short control interval. The simulation results state the benefits of multiple property CD control over single property control and single property control using full feedforward compensation. The controller presented may also be tuned in automated manner and the results demonstrate the effect of tuning on input saturation.
7. Supporting multiple control systems at Fermilab
Nicklaus, Dennis J.; /Fermilab
2009-10-01
The Fermilab control system, ACNET, is used for controlling the Tevatron and all of its pre-accelerators. However, other smaller experiments at Fermilab have been using different controls systems, in particular DOOCS and EPICS. This paper reports some of the steps taken at Fermilab to integrate support for these outside systems. We will describe specific tools that we have built or adapted to facilitate interaction between the architectures. We also examine some of the difficulties that arise from managing this heterogeneous environment. Incompatibilities as well as common elements will be described.
8. Managers’ Use of Multiple Management Control Systems
Willert, Jeanette
This dissertation addresses the topic Management Control Systems (MCS) as a Package. Many research studies investigate management and control systems individually, whereas fewer research studies take a holistic view and include a larger part of all the MCS managers use to guide and direct...... subordinates behaviour in the best interest of their companies. In the MCS literature, it is stressed that knowledge is particularly lacking about how managers design and use MCS as a package, and the effectiveness of using the MCS. This dissertation responds to this call by carrying out a large survey among...... executive managers in large companies, a survey that investigates the subject: Effective Management and Control Systems. The focus in the survey is to explore how executive management in large companies design and use their management control systems package. Further, this study is supplemented...
9. Flight mission control for multiple spacecraft
Ryan, Robert E.
1990-10-01
A plan developed by the Jet Propulsion Laboratory for mission control of unmanned spacecraft is outlined. A technical matrix organization from which, in the past, project teams were formed to uniquely support a mission is replaced in this new plan. A cost effective approach was needed to make best use of limited resources. Mission control is a focal point operations and a good place to start a multimission concept. Co-location and sharing common functions are the keys to obtaining efficiencies at minimum additional risk. For the projects, the major changes are sharing a common operations area and having indirect control of personnel. The plan identifies the still direct link for the mission control functions. Training is a major element in this plan. Personnel are qualified for a position and certified for a mission. This concept is more easily accepted by new missions than the ongoing missions.
10. Simultaneous Multiple-Location Separation Control
Greenblatt, David (Inventor)
2009-01-01
A method of controlling a shear layer for a fluid dynamic body introduces first periodic disturbances into the fluid medium at a first flow separation location. Simultaneously, second periodic disturbances are introduced into the fluid medium at a second flow separation location. A phase difference between the first and second periodic disturbances is adjusted to control flow separation of the shear layer as the fluid medium moves over the fluid dynamic body.
11. Smart transactive energy framework in grid-connected multiple home microgrids under independent and coalition operations
Marzband, Mousa; Azarinejadian, Fatemeh; Savaghebi, Mehdi
2018-01-01
This paper presents a smart Transactive energy (TE) framework in which home microgrids (H-MGs) can collaborate with each other in a multiple H-MG system by forming coalitions for gaining competitiveness in the market. Profit allocation due to coalition between H-MGs is an important issue...
12. Least squares reverse time migration of controlled order multiples
Liu, Y.
2016-12-01
Imaging using the reverse time migration of multiples generates inherent crosstalk artifacts due to the interference among different order multiples. Traditionally, least-square fitting has been used to address this issue by seeking the best objective function to measure the amplitude differences between the predicted and observed data. We have developed an alternative objective function by decomposing multiples into different orders to minimize the difference between Born modeling predicted multiples and specific-order multiples from observational data in order to attenuate the crosstalk. This method is denoted as the least-squares reverse time migration of controlled order multiples (LSRTM-CM). Our numerical examples demonstrated that the LSRTM-CM can significantly improve image quality compared with reverse time migration of multiples and least-square reverse time migration of multiples. Acknowledgments This research was funded by the National Nature Science Foundation of China (Grant Nos. 41430321 and 41374138).
13. Combining Multiple Features for Text-Independent Writer Identification and Verification
Bulacu , Marius; Schomaker , Lambert
2006-01-01
http://www.suvisoft.com; In recent years, we proposed a number of new and very effective features for automatic writer identification and verification. They are probability distribution functions (PDFs) extracted from the handwriting images and characterize writer individuality independently of the textual content of the written samples. In this paper, we perform an extensive analysis of feature combinations. In our fusion scheme, the final unique distance between two handwritten samples is c...
14. Recurrent Rearrangements of Human Amylase Genes Create Multiple Independent CNV Series.
Shwan, Nzar A A; Louzada, Sandra; Yang, Fengtang; Armour, John A L
2017-05-01
The human amylase gene cluster includes the human salivary (AMY1) and pancreatic amylase genes (AMY2A and AMY2B), and is a highly variable and dynamic region of the genome. Copy number variation (CNV) of AMY1 has been implicated in human dietary adaptation, and in population association with obesity, but neither of these findings has been independently replicated. Despite these functional implications, the structural genomic basis of CNV has only been defined in detail very recently. In this work, we use high-resolution analysis of copy number, and analysis of segregation in trios, to define new, independent allelic series of amylase CNVs in sub-Saharan Africans, including a series of higher-order expansions of a unit consisting of one copy each of AMY1, AMY2A, and AMY2B. We use fiber-FISH (fluorescence in situ hybridization) to define unexpected complexity in the accompanying rearrangements. These findings demonstrate recurrent involvement of the amylase gene region in genomic instability, involving at least five independent rearrangements of the pancreatic amylase genes (AMY2A and AMY2B). Structural features shared by fundamentally distinct lineages strongly suggest that the common ancestral state for the human amylase cluster contained more than one, and probably three, copies of AMY1. © 2017 WILEY PERIODICALS, INC.
15. Synergistic and independent actions of multiple terminal nucleotidyl transferases in the 3' tailing of small RNAs in Arabidopsis.
Xiaoyan Wang
2015-04-01
Full Text Available All types of small RNAs in plants, piwi-interacting RNAs (piRNAs in animals and a subset of siRNAs in Drosophila and C. elegans are subject to HEN1 mediated 3' terminal 2'-O-methylation. This modification plays a pivotal role in protecting small RNAs from 3' uridylation, trimming and degradation. In Arabidopsis, HESO1 is a major enzyme that uridylates small RNAs to trigger their degradation. However, U-tail is still present in null hen1 heso1 mutants, suggesting the existence of (an enzymatic activities redundant with HESO1. Here, we report that UTP: RNA uridylyltransferase (URT1 is a functional paralog of HESO1. URT1 interacts with AGO1 and plays a predominant role in miRNA uridylation when HESO1 is absent. Uridylation of miRNA is globally abolished in a hen1 heso1 urt1 triple mutant, accompanied by an extensive increase of 3'-to-5' trimming. In contrast, disruption of URT1 appears not to affect the heterochromatic siRNA uridylation. This indicates the involvement of additional nucleotidyl transferases in the siRNA pathway. Analysis of miRNA tailings in the hen1 heso1 urt1 triple mutant also reveals the existence of previously unknown enzymatic activities that can add non-uridine nucleotides. Importantly, we show HESO1 may also act redundantly with URT1 in miRNA uridylation when HEN1 is fully competent. Taken together, our data not only reveal a synergistic action of HESO1 and URT1 in the 3' uridylation of miRNAs, but also independent activities of multiple terminal nucleotidyl transferases in the 3' tailing of small RNAs and an antagonistic relationship between uridylation and trimming. Our results may provide further insight into the mechanisms of small RNA 3' end modification and stability control.
16. Control of multiple filamentation in air
Fibich, Gadi; Eisenmann, Shmuel; Ilan, Boaz; Zigler, Arie
2004-08-01
In this Letter we provide what is believed to be the first experimental evidence of suppression of the number of filaments for high-intensity laser pulses propagating in air by beam astigmatism. We also show that the number, pattern, and spatial stability of the filaments can be controlled by varying the angle that a focusing lens makes with the axial direction of propagation. This new methodology can be useful for applications involving atmospheric propagation, such as remote sensing.
17. Multiple brain networks underpinning word learning from fluent speech revealed by independent component analysis.
López-Barroso, Diana; Ripollés, Pablo; Marco-Pallarés, Josep; Mohammadi, Bahram; Münte, Thomas F; Bachoud-Lévi, Anne-Catherine; Rodriguez-Fornells, Antoni; de Diego-Balaguer, Ruth
2015-04-15
Although neuroimaging studies using standard subtraction-based analysis from functional magnetic resonance imaging (fMRI) have suggested that frontal and temporal regions are involved in word learning from fluent speech, the possible contribution of different brain networks during this type of learning is still largely unknown. Indeed, univariate fMRI analyses cannot identify the full extent of distributed networks that are engaged by a complex task such as word learning. Here we used Independent Component Analysis (ICA) to characterize the different brain networks subserving word learning from an artificial language speech stream. Results were replicated in a second cohort of participants with a different linguistic background. Four spatially independent networks were associated with the task in both cohorts: (i) a dorsal Auditory-Premotor network; (ii) a dorsal Sensory-Motor network; (iii) a dorsal Fronto-Parietal network; and (iv) a ventral Fronto-Temporal network. The level of engagement of these networks varied through the learning period with only the dorsal Auditory-Premotor network being engaged across all blocks. In addition, the connectivity strength of this network in the second block of the learning phase correlated with the individual variability in word learning performance. These findings suggest that: (i) word learning relies on segregated connectivity patterns involving dorsal and ventral networks; and (ii) specifically, the dorsal auditory-premotor network connectivity strength is directly correlated with word learning performance. Copyright © 2015 Elsevier Inc. All rights reserved.
18. Control of Multiple Robotic Sentry Vehicles
Feddema, J.; Klarer, P.; Lewis, C.
1999-04-01
19. Independent Blade Pitch Controller Design for a Three-Bladed Turbine Using Disturbance Accommodating Control
Wang, Na; Wright, Alan D.; Johnson, Kathryn E.
2016-08-01
Two independent pitch controllers (IPCs) based on the disturbance accommodating control (DAC) algorithm are designed for the three-bladed Controls Advanced Research Turbine to regulate rotor speed and to mitigate blade root flapwise bending loads in above-rated wind speed. One of the DAC-based IPCs is designed based on a transformed symmetrical-asymmetrical (TSA) turbine model, with wind disturbances being modeled as a collective horizontal component and an asymmetrical linear shear component. Another DAC-based IPC is designed based on a multiblade coordinate (MBC) transformed turbine model, with a horizontal component and a vertical shear component being modeled as step waveform disturbance. Both of the DAC-based IPCs are found via a regulation equation solved by Kronecker product. Actuator dynamics are considered in the design processes to compensate for actuator phase delay. The simulation study shows the effectiveness of the proposed DAC-based IPCs compared to a proportional-integral (PI) collective pitch controller (CPC). Improvement on rotor speed regulation and once-per-revolution and twice-per-revolution load reductions has been observed in the proposed IPC designs.
20. Independent Blade Pitch Controller Design for a Three-Bladed Turbine Using Disturbance Accommodating Control: Preprint
Wang, Na; Wright, Alan D.; Johnson, Kathryn E.
2016-07-29
Two independent pitch controllers (IPCs) based on the disturbance accommodating control (DAC) algorithm are designed for the three-bladed Controls Advanced Research Turbine to regulate rotor speed and to mitigate blade root flapwise bending loads in above-rated wind speed. One of the DAC-based IPCs is designed based on a transformed symmetrical-asymmetrical (TSA) turbine model, with wind disturbances being modeled as a collective horizontal component and an asymmetrical linear shear component. Another DAC-based IPC is designed based on a multiblade coordinate (MBC) transformed turbine model, with a horizontal component and a vertical shear component being modeled as step waveform disturbance. Both of the DAC-based IPCs are found via a regulation equation solved by Kronecker product. Actuator dynamics are considered in the design processes to compensate for actuator phase delay. The simulation study shows the effectiveness of the proposed DAC-based IPCs compared to a proportional-integral (PI) collective pitch controller (CPC). Improvement on rotor speed regulation and once-per-revolution and twice-per-revolution load reductions has been observed in the proposed IPC designs.
1. Design of driving control strategy of torque distribution for two - wheel independent drive electric vehicle
Zhang, Chuanwei; Zhang, Dongsheng; Wen, Jianping
2018-02-01
In order to coordinately control the torque distribution of existing two-wheel independent drive electric vehicle, and improve the energy efficiency and control stability of the whole vehicle, the control strategies based on fuzzy control were designed which adopt the direct yaw moment control as the main line. For realizing the torque coordination simulation of the two-wheel independent drive vehicle, the vehicle model, motor model and tire model were built, including the vehicle 7 - DOF dynamics model, motion equation, torque equation. Finally, in the Carsim - Simulink joint simulation platform, the feasibility of the drive control strategy was verified.
2. Color, Scale, and Rotation Independent Multiple License Plates Detection in Videos and Still Images
Narasimha Reddy Soora
2016-01-01
Full Text Available Most of the existing license plate (LP detection systems have shown significant development in the processing of the images, with restrictions related to environmental conditions and plate variations. With increased mobility and internationalization, there is a need to develop a universal LP detection system, which can handle multiple LPs of many countries and any vehicle, in an open environment and all weather conditions, having different plate variations. This paper presents a novel LP detection method using different clustering techniques based on geometrical properties of the LP characters and proposed a new character extraction method, for noisy/missed character components of the LP due to the presence of noise between LP characters and LP border. The proposed method detects multiple LPs from an input image or video, having different plate variations, under different environmental and weather conditions because of the geometrical properties of the set of characters in the LP. The proposed method is tested using standard media-lab and Application Oriented License Plate (AOLP benchmark LP recognition databases and achieved the success rates of 97.3% and 93.7%, respectively. Results clearly indicate that the proposed approach is comparable to the previously published papers, which evaluated their performance on publicly available benchmark LP databases.
3. Non-local coexistence of multiple spiral waves with independent frequencies
Zhan Meng; Luo Jinming
2009-01-01
The interactions of several spiral waves with different independent rotation frequencies are studied in a model of two-dimensional complex Ginzburg-Laudau equation. We find a general coexistence phenomenon, non-local non-phase-locking-invasion coexistence, that is, the non-slowest spiral wave can survive and not be killed by the fastest spiral wave as it is insulated from the fastest one with the sacrifice of the slowest one, which stays in the spatial position between the fastest spiral and the non-slowest one. Both the parameter non-monotonicity and the non-phase-locking invasion between the fastest and the slowest spiral waves play key roles in this phenomenon. Importantly, the results could give a general idea for extensively observed coexistence of spiral waves in various inhomogeneous circumstances.
4. Completely independent electrical control of spin and valley in a silicene field effect transistor
Zhai, Xuechao; Jin, Guojun
2016-01-01
One-atom-thick silicene is a silicon-based hexagonal-lattice material with buckled structure, where an electron fuses multiple degrees of freedom including spin, sublattice pseudospin and valley. We here demonstrate that a valley-selective spin filter (VSSF) that supports single-valley and single-spin transport can be realized in a silicene field effect transistor constructed of an npn junction, where an antiferromagnetic exchange field and a perpendicular electric field are applied in the p -doped region. The nontrivial VSSF property benefits from an electrically controllable state of spin-polarized single-valley Dirac cone. By reversing the electric field direction, the device can operate as a spin-reversed but valley-unreversed filter due to the dependence of band gap on spin and valley. Further, we find that all the possible spin-valley configurations of VSSF can be achieved just by tuning the electric field. Our findings pave the way to the realization of completely independent electrical control of spin and valley in silicene circuits. (paper)
5. A Comparison of Mangrove Canopy Height Using Multiple Independent Measurements from Land, Air, and Space
Lagomasino, David; Fatoyinbo, Temilola; Lee, SeungKuk; Feliciano, Emanuelle; Trettin, Carl; Simard, Marc
2016-01-01
Canopy height is one of the strongest predictors of biomass and carbon in forested ecosystems. Additionally, mangrove ecosystems represent one of the most concentrated carbon reservoirs that are rapidly degrading as a result of deforestation, development, and hydrologic manipulation. Therefore, the accuracy of Canopy Height Models (CHM) over mangrove forest can provide crucial information for monitoring and verification protocols. We compared four CHMs derived from independent remotely sensed imagery and identified potential errors and bias between measurement types. CHMs were derived from three spaceborne datasets; Very-High Resolution (VHR) stereophotogrammetry, TerraSAR-X add-on for Digital Elevation Measurement (DEM), and Shuttle Radar Topography Mission (TanDEM-X), and lidar data which was acquired from an airborne platform. Each dataset exhibited different error characteristics that were related to spatial resolution, sensitivities of the sensors, and reference frames. Canopies over 10 meters were accurately predicted by all CHMs while the distributions of canopy height were best predicted by the VHR CHM. Depending on the guidelines and strategies needed for monitoring and verification activities, coarse resolution CHMs could be used to track canopy height at regional and global scales with finer resolution imagery used to validate and monitor critical areas undergoing rapid changes.
6. Tempo and mode of performance evolution across multiple independent origins of adhesive toe pads in lizards.
Hagey, Travis J; Uyeda, Josef C; Crandell, Kristen E; Cheney, Jorn A; Autumn, Kellar; Harmon, Luke J
2017-10-01
Understanding macroevolutionary dynamics of trait evolution is an important endeavor in evolutionary biology. Ecological opportunity can liberate a trait as it diversifies through trait space, while genetic and selective constraints can limit diversification. While many studies have examined the dynamics of morphological traits, diverse morphological traits may yield the same or similar performance and as performance is often more proximately the target of selection, examining only morphology may give an incomplete understanding of evolutionary dynamics. Here, we ask whether convergent evolution of pad-bearing lizards has followed similar evolutionary dynamics, or whether independent origins are accompanied by unique constraints and selective pressures over macroevolutionary time. We hypothesized that geckos and anoles each have unique evolutionary tempos and modes. Using performance data from 59 species, we modified Brownian motion (BM) and Ornstein-Uhlenbeck (OU) models to account for repeated origins estimated using Bayesian ancestral state reconstructions. We discovered that adhesive performance in geckos evolved in a fashion consistent with Brownian motion with a trend, whereas anoles evolved in bounded performance space consistent with more constrained evolution (an Ornstein-Uhlenbeck model). Our results suggest that convergent phenotypes can have quite distinctive evolutionary patterns, likely as a result of idiosyncratic constraints or ecological opportunities. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.
7. A 2.9 ps equivalent resolution interpolating time counter based on multiple independent coding lines
Szplet, R; Jachna, Z; Kwiatkowski, P; Rozyc, K
2013-01-01
We present the design, operation and test results of a time counter that has an equivalent resolution of 2.9 ps, a measurement uncertainty at the level of 6 ps, and a measurement range of 10 s. The time counter has been implemented in a general-purpose reprogrammable device Spartan-6 (Xilinx). To obtain both high precision and wide measurement range the counting of periods of a reference clock is combined with a two-stage interpolation within a single period of the clock signal. The interpolation involves a four-phase clock in the first interpolation stage (FIS) and an equivalent coding line (ECL) in the second interpolation stage (SIS). The ECL is created as a compound of independent discrete time coding lines (TCL). The number of TCLs used to create the virtual ECL has an effect on its resolution. We tested ECLs made from up to 16 TCLs, but the idea may be extended to a larger number of lines. In the presented time counter the coarse resolution of the counting method equal to 2 ns (period of the 500 MHz reference clock) is firstly improved fourfold in the FIS and next even more than 400 times in the SIS. The proposed solution allows us to overcome the technological limitation in achievable resolution and improve the precision of conversion of integrated interpolators based on tapped delay lines. (paper)
8. Multiple independent colonization of the Canary Islands by the winged grasshopper genus Sphingonotus Fieber, 1852.
Husemann, Martin; Deppermann, Jana; Hochkirch, Axel
2014-12-01
Volcanic archipelagos represent ideal systems to study processes of colonization, differentiation and speciation. The Canary Islands are one of the best studied archipelagos, being composed of seven main islands with a well-known geological history. Most taxa have colonized these islands stepwise from the African or Iberian mainland from east to west, following their geological origin as well as the predominating wind direction and ocean currents. Furthermore, within-island radiations have been reported for several taxa. The grasshopper genus Sphingonotus is species-rich and occurs with nine fully winged species on the Canary Islands, seven of which are endemic to single or few islands. We inferred a phylogeny of these species and their North African and Iberian relatives based upon sequences of three mitochondrial genes and one nuclear gene of 136 specimens. Surprisingly, our results suggest that almost all Sphingonotus species colonized the archipelago independently from the mainland and nearly no inter-island colonization occurred. Despite their strong flight capabilities, only one pair of endemic species are closely related (S. sublaevis from Gran Canary and S. pachecoi from Lanzarote). Moreover, no within-island speciation events were detected. We hypothesize that passive wind dispersal from the African mainland was the main driver of the colonization process and that most Sphingonotus species are not able to cover inter-island distances by active flight. This, together with strong intrageneric niche overlap might explain the lack of within-island speciation in this taxon. Copyright © 2014 Elsevier Inc. All rights reserved.
9. Comparing soil moisture anomalies from multiple independent sources over different regions across the globe
2017-12-01
Agricultural drought events can affect large regions across the world, implying the need for a suitable global tool for an accurate monitoring of this phenomenon. Soil moisture anomalies are considered a good metric to capture the occurrence of agricultural drought events, and they have become an important component of several operational drought monitoring systems. In the framework of the JRC Global Drought Observatory (GDO, eu/gdo/" target="_blank">http://edo.jrc.ec.europa.eu/gdo/), the suitability of three datasets as possible representations of root zone soil moisture anomalies has been evaluated: (1) the soil moisture from the Lisflood distributed hydrological model (namely LIS), (2) the remotely sensed Land Surface Temperature data from the MODIS satellite (namely LST), and (3) the ESA Climate Change Initiative combined passive/active microwave skin soil moisture dataset (namely CCI). Due to the independency of these three datasets, the triple collocation (TC) technique has been applied, aiming at quantifying the likely error associated with each dataset in comparison to the unknown true status of the system. TC analysis was performed on five macro-regions (namely North America, Europe, India, southern Africa and Australia) detected as suitable for the experiment, providing insight into the mutual relationship between these datasets as well as an assessment of the accuracy of each method. Even if no definitive statement on the spatial distribution of errors can be provided, a clear outcome of the TC analysis is the good performance of the remote sensing datasets, especially CCI, over dry regions such as Australia and southern Africa, whereas the outputs of LIS seem to be more reliable over areas that are well monitored through meteorological ground station networks, such as North America and Europe. In a global drought monitoring system, the results of the error analysis are used to design a weighted-average ensemble system that exploits the advantages of
10. Comparing soil moisture anomalies from multiple independent sources over different regions across the globe
C. Cammalleri
2017-12-01
Full Text Available Agricultural drought events can affect large regions across the world, implying the need for a suitable global tool for an accurate monitoring of this phenomenon. Soil moisture anomalies are considered a good metric to capture the occurrence of agricultural drought events, and they have become an important component of several operational drought monitoring systems. In the framework of the JRC Global Drought Observatory (GDO, http://edo.jrc.ec.europa.eu/gdo/, the suitability of three datasets as possible representations of root zone soil moisture anomalies has been evaluated: (1 the soil moisture from the Lisflood distributed hydrological model (namely LIS, (2 the remotely sensed Land Surface Temperature data from the MODIS satellite (namely LST, and (3 the ESA Climate Change Initiative combined passive/active microwave skin soil moisture dataset (namely CCI. Due to the independency of these three datasets, the triple collocation (TC technique has been applied, aiming at quantifying the likely error associated with each dataset in comparison to the unknown true status of the system. TC analysis was performed on five macro-regions (namely North America, Europe, India, southern Africa and Australia detected as suitable for the experiment, providing insight into the mutual relationship between these datasets as well as an assessment of the accuracy of each method. Even if no definitive statement on the spatial distribution of errors can be provided, a clear outcome of the TC analysis is the good performance of the remote sensing datasets, especially CCI, over dry regions such as Australia and southern Africa, whereas the outputs of LIS seem to be more reliable over areas that are well monitored through meteorological ground station networks, such as North America and Europe. In a global drought monitoring system, the results of the error analysis are used to design a weighted-average ensemble system that exploits the advantages of each dataset.
11. Independent motion control of a tower crane through wireless sensor and actuator networks.
Koumboulis, Fotis N; Kouvakas, Nikolaos D; Giannaris, George L; Vouyioukas, Demosthenes
2016-01-01
The problem of independent control of the performance variables of a tower crane through a wireless sensor and actuator network is investigated. The complete nonlinear mathematical model of the tower crane is developed. Based on appropriate data driven norms an accurate linear approximant of the system, including an upper bound of the communication delays, is derived. Using this linear approximant, a dynamic measurable output multi delay controller for independent control of the performance outputs of the system is proposed. The controller performs satisfactory despite the nonlinearities of the model and the communication delays of the wireless network. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.
12. Realtime control of multiple-focus phased array heating patterns based on noninvasive ultrasound thermography.
Casper, Andrew; Liu, Dalong; Ebbini, Emad S
2012-01-01
A system for the realtime generation and control of multiple-focus ultrasound phased-array heating patterns is presented. The system employs a 1-MHz, 64-element array and driving electronics capable of fine spatial and temporal control of the heating pattern. The driver is integrated with a realtime 2-D temperature imaging system implemented on a commercial scanner. The coordinates of the temperature control points are defined on B-mode guidance images from the scanner, together with the temperature set points and controller parameters. The temperature at each point is controlled by an independent proportional, integral, and derivative controller that determines the focal intensity at that point. Optimal multiple-focus synthesis is applied to generate the desired heating pattern at the control points. The controller dynamically reallocates the power available among the foci from the shared power supply upon reaching the desired temperature at each control point. Furthermore, anti-windup compensation is implemented at each control point to improve the system dynamics. In vitro experiments in tissue-mimicking phantom demonstrate the robustness of the controllers for short (2-5 s) and longer multiple-focus high-intensity focused ultrasound exposures. Thermocouple measurements in the vicinity of the control points confirm the dynamics of the temperature variations obtained through noninvasive feedback. © 2011 IEEE
13. Multiple independent insertions of 5S rRNA genes in the spliced-leader gene family of trypanosome species.
Beauparlant, Marc A; Drouin, Guy
2014-02-01
Analyses of the 5S rRNA genes found in the spliced-leader (SL) gene repeat units of numerous trypanosome species suggest that such linkages were not inherited from a common ancestor, but were the result of independent 5S rRNA gene insertions. In trypanosomes, 5S rRNA genes are found either in the tandemly repeated units coding for SL genes or in independent tandemly repeated units. Given that trypanosome species where 5S rRNA genes are within the tandemly repeated units coding for SL genes are phylogenetically related, one might hypothesize that this arrangement is the result of an ancestral insertion of 5S rRNA genes into the tandemly repeated SL gene family of trypanosomes. Here, we use the types of 5S rRNA genes found associated with SL genes, the flanking regions of the inserted 5S rRNA genes and the position of these insertions to show that most of the 5S rRNA genes found within SL gene repeat units of trypanosome species were not acquired from a common ancestor but are the results of independent insertions. These multiple 5S rRNA genes insertion events in trypanosomes are likely the result of frequent founder events in different hosts and/or geographical locations in species having short generation times.
14. Independent and inverse association of healthcare utilisation with physical activity in older adults with multiple chronic conditions.
Liu-Ambrose, T Y L; Ashe, M C; Marra, C
2010-11-01
In this study, whether physical activity is independently associated with direct healthcare costs in community-dwelling older adults with multiple chronic conditions was examined. Cross-sectional analysis. Research laboratory. 299 community-dwelling men and women volunteers aged 65 years and older with chronic conditions. None. Primary dependent variable was direct healthcare costs incurred in the previous 3 months. Participants completed the Health Resource Utilisation (HRU) questionnaire. To estimate HRU, direct costs in the previous 3 months were calculated using the three-party payer perspective of the British Columbia Ministry of Health, deemed representative of the Canadian healthcare system costs. For medications, the Retail Pharmacy Dispensed prescription cost tables were used. Primary independent variables were (1) self-report current level of physical activity as assessed by the Physical Activity Scale for Individuals with Physical Disabilities (PASIPD) and (2) general balance and mobility as assessed by the National Institute on Aging Balance Scale. The mean number of chronic conditions per participant was six. Current level of physical activity was independently and inversely associated with HRU. Age, sex, number of chronic conditions, global cognitive function, body mass index, and general balance and mobility together accounted for 24.3% of the total variance. Adding the PASIPD score resulted in an R2 change of 3.3% and significantly improved the model. The total variance accounted by the final model was 27.6%. Physical activity promotion may reduce healthcare costs in older adults with chronic conditions.
15. Evidence from intrinsic activity that asymmetry of the human brain is controlled by multiple factors.
Liu, Hesheng; Stufflebeam, Steven M; Sepulcre, Jorge; Hedden, Trey; Buckner, Randy L
2009-12-01
Cerebral lateralization is a fundamental property of the human brain and a marker of successful development. Here we provide evidence that multiple mechanisms control asymmetry for distinct brain systems. Using intrinsic activity to measure asymmetry in 300 adults, we mapped the most strongly lateralized brain regions. Both men and women showed strong asymmetries with a significant, but small, group difference. Factor analysis on the asymmetric regions revealed 4 separate factors that each accounted for significant variation across subjects. The factors were associated with brain systems involved in vision, internal thought (the default network), attention, and language. An independent sample of right- and left-handed individuals showed that hand dominance affects brain asymmetry but differentially across the 4 factors supporting their independence. These findings show the feasibility of measuring brain asymmetry using intrinsic activity fluctuations and suggest that multiple genetic or environmental mechanisms control cerebral lateralization.
16. Influenza A virus targets a cGAS-independent STING pathway that controls enveloped RNA viruses.
Holm, Christian K; Rahbek, Stine H; Gad, Hans Henrik; Bak, Rasmus O; Jakobsen, Martin R; Jiang, Zhaozaho; Hansen, Anne Louise; Jensen, Simon K; Sun, Chenglong; Thomsen, Martin K; Laustsen, Anders; Nielsen, Camilla G; Severinsen, Kasper; Xiong, Yingluo; Burdette, Dara L; Hornung, Veit; Lebbink, Robert Jan; Duch, Mogens; Fitzgerald, Katherine A; Bahrami, Shervin; Mikkelsen, Jakob Giehm; Hartmann, Rune; Paludan, Søren R
2016-02-19
Stimulator of interferon genes (STING) is known be involved in control of DNA viruses but has an unexplored role in control of RNA viruses. During infection with DNA viruses STING is activated downstream of cGAMP synthase (cGAS) to induce type I interferon. Here we identify a STING-dependent, cGAS-independent pathway important for full interferon production and antiviral control of enveloped RNA viruses, including influenza A virus (IAV). Further, IAV interacts with STING through its conserved hemagglutinin fusion peptide (FP). Interestingly, FP antagonizes interferon production induced by membrane fusion or IAV but not by cGAMP or DNA. Similar to the enveloped RNA viruses, membrane fusion stimulates interferon production in a STING-dependent but cGAS-independent manner. Abolishment of this pathway led to reduced interferon production and impaired control of enveloped RNA viruses. Thus, enveloped RNA viruses stimulate a cGAS-independent STING pathway, which is targeted by IAV.
17. Motion Control of Four-Wheel Independently Actuated Electric Ground Vehicles considering Tire Force Saturations
Rongrong Wang
2013-01-01
Full Text Available A vehicle stability control approach for four-wheel independently actuated (FWIA electric vehicles is presented. The proposed control method consists of a higher-level controller and a lower-level controller. An adaptive control-based higher-level controller is designed to yield the vehicle virtual control efforts to track the desired vehicle motions due to the possible modeling inaccuracies and parametric uncertainties. The lower-level controller considering tire force saturation is given to allocate the required control efforts to the four in-wheel motors for providing the desired tire forces. An analytic method is given to distribute the high-level control efforts, without using the numerical-optimization-based control allocation algorithms. Simulations based on a high-fidelity, CarSim, and full-vehicle model show the effectiveness of the control approach.
18. Performance effect of multiple control forms in a Lean organization
Kristensen, Thomas Borup; Israelsen, Poul
2012-01-01
Over the last decades Lean has developed into a prominent management philosophy reaching beyond shop floor tools. However, substantial support of performance effects from Lean is still scarce and at best with mixed results. Recently, research has turned its focus towards perceiving Lean...... as a control package. In this paper we present statistical support for enhanced performance coming from Lean. Furthermore, our results strongly support the perception of Lean as a set of multiple control forms (output, behavioral, and social controls) that complement each other. Therefore, performance...... is increased if the average level of control forms is increased, and performance is further increased if the control forms are balanced at the same level representing a complementary effect between them. Our data are archival data spanning multiple years in a strong Lean organization. The dependent performance...
19. Independent clonal origin of multiple uterine leiomyomas that was determined by X chromosome inactivation and microsatellite analysis
Canevari, Renata A; Pontes, Anaglória; Rosa, Fabíola E
2005-01-01
OBJECTIVE: In an attempt to clarify the clonality and genetic relationships that are involved in the tumorigenesis of uterine leiomyomas, we used a total of 43 multiple leiomyomas from 14 patients and analyzed the allelic status with 15 microsatellite markers and X chromosome inactivation analysis...... of the 9 of 12 informative patients; different inactivation patterns were observed in 3 cases. CONCLUSION: Our data support the concept that uterine leiomyomas are derived from a single cell but are generated independently in the uterus. Loss of heterozygosity findings at 7p22-15 are consistent...... with previous data that suggested the relevance of chromosomal aberrations at 7p that were involved in individual uterine leiomyomas....
20. Two adults with multiple disabilities use a computer-aided telephone system to make phone calls independently.
Lancioni, Giulio E; O'Reilly, Mark F; Singh, Nirbhay N; Sigafoos, Jeff; Oliva, Doretta; Alberti, Gloria; Lang, Russell
2011-01-01
This study extended the assessment of a newly developed computer-aided telephone system with two participants (adults) who presented with blindness or severe visual impairment and motor or motor and intellectual disabilities. For each participant, the study was carried out according to an ABAB design, in which the A represented baseline phases and the B represented intervention phases, during which the special telephone system was available. The system involved among others a net-book computer provided with specific software, a global system for mobile communication modem, and a microswitch. Both participants learned to use the system very rapidly and managed to make phone calls independently to a variety of partners such as family members, friends and staff personnel. The results were discussed in terms of the technology under investigation (its advantages, drawbacks, and need of improvement) and the social-communication impact it can make for persons with multiple disabilities. Copyright © 2011 Elsevier Ltd. All rights reserved.
1. A novel nine-switch inverter for independent control of two three-phase loads
Kominami, Tsutomu; Fujimoto, Yasutaka
2007-01-01
Industrial applications require large numbers of motors. For example, motors are used to manipulate industrial robots, an electric vehicles with in-wheel motors and electric trains. Two methods exist for controlling PM motors providing an inverter to control each motor, and connecting the motors in parallel and driving them with a single inverter. The first method makes an experimental apparatus complex and expensive; the second does not allow independent control of each motor because of diff...
2. Accelerated spike resampling for accurate multiple testing controls.
Harrison, Matthew T
2013-02-01
Controlling for multiple hypothesis tests using standard spike resampling techniques often requires prohibitive amounts of computation. Importance sampling techniques can be used to accelerate the computation. The general theory is presented, along with specific examples for testing differences across conditions using permutation tests and for testing pairwise synchrony and precise lagged-correlation between many simultaneously recorded spike trains using interval jitter.
3. Chance Events in Career Development: Influence, Control and Multiplicity
Bright, Jim E. H.; Pryor, Robert G. L.; Chan, Eva Wing Man; Rijanto, Jeniyanti
2009-01-01
This article reports three studies on the nature and impact of chance events. The first study investigated chance events in terms of the dimensions of influence and control. The second and third studies investigated the effects of multiplicity of chance events on career development are in terms of respondents' own careers and then in terms of…
Abe, Shinya; Nakata, Yutaka; Iitsuka, Tomoaki; Yamagishi, Kojiro
2003-10-01
Japanese government is carrying out the administrative reform aiming to promote decentralization of authority, to magnify the field of private sectors, etc. in order to corresponds appropriately to matured economy, internationalized market, etc. As one of the reforms, Japanese government decided that JAERI and JNC would unite into an independent administrative agency. The aims of the independent administrative agency institution include realization of effective and transparent system and management. The aim of the present investigation is to be useful for the new agency to develop a major business control system, which manages financial affairs and accounts not only efficiently but also in correspondence with open information to the public and promoting research activities effectively. First of all, the authors examined Japanese laws and standards relating to the independent administrative agency. They investigated the financial affairs and accounts systems of the preceding independent administrative agencies for research and development and also the development trends of work-flow systems in private enterprises in Japan. They considered expected problems and solutions for developing and making use of the major business control system. On the basis of the above investigations, the authors revealed the total concept of the best major business control system of the new unified agency besides the necessary conditions of the system for an independent administrative agency. Additionally, the above mentioned laws and standards are collected in an appendix. (author)
5. Impulse control disorders are associated with multiple psychiatric symptoms in Parkinson's disease.
Jaakkola, Elina; Kaasinen, Valtteri; Siri, Chiara; Martikainen, Kirsti; Cilia, Roberto; Niemelä, Solja; Joutsa, Juho
2014-01-01
Impulse control disorders can have serious adverse consequences to the life of a patient with Parkinson's disease. Although impulse control disorders are common, a possible psychiatric comorbidity has not been fully characterized. The aim of this study was to investigate the psychiatric symptoms exhibited by Parkinson's disease patients with impulse control disorders. The study was conducted as a postal survey to patients in the registry of the Finnish Parkinson Association. A total of 290 Parkinson's disease patients were evaluated for impulse control disorders using the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease. Psychiatric symptoms were systematically screened using the Symptom Checklist 90. We found that 108 of the evaluated patients had one or more impulse control disorders. Patients with impulse control disorders had markedly higher scores for symptoms of psychoticism (Bonferroni corrected p disorder (p impulse control disorders. Impulse control disorders were shown to be independently associated with these symptoms. Patients with multiple impulse control disorders had higher scores for depression and obsessive-compulsive symptoms when compared with patients that exhibited only one impulse control disorder. COUNCLUSIONS: Our results confirm the previous observations that impulse control disorders in Parkinson's disease are linked with multiple psychiatric symptoms, including psychoticism, interpersonal sensitivity, obsessive-compulsive symptoms and depression. Clinicians treating these patients should acknowledge the concomitant psychiatric symptoms.
6. The Multiplicity of Controls and the Making of Innovation
Revellino, Silvana; Mouritsen, Jan
2009-01-01
are mediated by unique sets of technologies of control. In this process the innovation changes and adapts. This thesis is drawn from the case of Italian Autostrade's innovation Telepass which was an automatic toll collection devise developed to make traffic fast, safe and fluid. Throughout its development...... satisfaction, productivity and highly pointed achievement targets. This multiplicity of controls changed and adapted to the innovation as the innovation unfolds. The controls were part of the innovation more likely than an external device to make it transparent. They engaged the individual trials and changed...
7. Ethical Issues Relative to Autonomy and Personal Control in Independent and Cognitively Impaired Elders.
Rice, Virginia Hill; And Others
1997-01-01
Discusses ethical issues surrounding health care for independent elders, those in long-term care, and those with cognitive impairments, as well as death, dying, euthanasia, and assisted suicide. Suggests that nurses should focus on older adults' choice, autonomy, and personal control. (SK)
8. Wide frequency independently controlled dual-band inkjet-printed antenna
AbuTarboush, Hattan F.; Shamim, Atif
2014-01-01
.2 and 23.7%, respectively. These dual-bands have the ability to be controlled independently between 1.1 and 7.5 GHz without affecting the other band. In addition, the proposed antenna can be assigned for different mobile and wireless applications
9. Independently Controlled Wing Stroke Patterns in the Fruit Fly Drosophila melanogaster
Chakraborty, Soma; Bartussek, Jan; Fry, S.N.; Zápotocký, Martin
2015-01-01
Roč. 10, č. 2 (2015), e0116813 E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GBP304/12/G069 Institutional support: RVO:67985823 Keywords : motor control * wing kinematics * independent component analysis Subject RIV: ED - Physiology Impact factor: 3.057, year: 2015
10. Young-Age Gender Differences in Mathematics Mediated by Independent Control or Uncontrollability
Zirk-Sadowski, Jan; Lamptey, Charlotte; Devine, Amy; Haggard, Mark; Szucs, Dénes
2014-01-01
We studied whether the origins of math anxiety can be related to a biologically supported framework of stress induction: (un)controllability perception, here indicated by self-reported independent efforts in mathematics. Math anxiety was tested in 182 children (8- to 11-year-olds). "Latent factor modeling" was used to test hypotheses on…
11. Nonresonant Multiple-Pulse Control of Molecular Motions in Liquid
Nikiforov V.G.
2015-01-01
Full Text Available We propose the implementation of the multiple-pulse excitation for manipulation of the molecular contributions to the optically-heterodyne-detected optical-Kerr-effect. The key parameters controlling the specificity of the multiple-pulse excitation scenarios are the pulses durations, the delays between pulses, the relation between the pump pulses amplitudes and the pulses polarizations. We model the high-order optical responses and consider some principles of the scenarios construction. We show that it is possible to adjust the excitation scenario in such a way that the some responses can be removed from detected signal along with the enhancement of the interested response amplitude. The theoretical analysis and first experimental data reveal that the multiple-pulse excitation technique can be useful for the selective spectroscopy of the molecular vibrations and rotations in liquid.
12. Independent assessment to continue improvement: Implementing statistical process control at the Hanford Site
Hu, T.A.; Lo, J.C.
1994-11-01
A Quality Assurance independent assessment has brought about continued improvement in the PUREX Plant surveillance program at the Department of Energy's Hanford Site. After the independent assessment, Quality Assurance personnel were closely involved in improving the surveillance program, specifically regarding storage tank monitoring. The independent assessment activities included reviewing procedures, analyzing surveillance data, conducting personnel interviews, and communicating with management. Process improvement efforts included: (1) designing data collection methods; (2) gaining concurrence between engineering and management, (3) revising procedures; and (4) interfacing with shift surveillance crews. Through this process, Statistical Process Control (SPC) was successfully implemented and surveillance management was improved. The independent assessment identified several deficiencies within the surveillance system. These deficiencies can be grouped into two areas: (1) data recording and analysis and (2) handling off-normal conditions. By using several independent assessment techniques, Quality Assurance was able to point out program weakness to senior management and present suggestions for improvements. SPC charting, as implemented by Quality Assurance, is an excellent tool for diagnosing the process, improving communication between the team members, and providing a scientific database for management decisions. In addition, the surveillance procedure was substantially revised. The goals of this revision were to (1) strengthen the role of surveillance management, engineering and operators and (2) emphasize the importance of teamwork for each individual who performs a task. In this instance we believe that the value independent assessment adds to the system is the continuous improvement activities that follow the independent assessment. Excellence in teamwork between the independent assessment organization and the auditee is the key to continuing improvement
13. A comparison on parameter-estimation methods in multiple regression analysis with existence of multicollinearity among independent variables
Hukharnsusatrue, A.
2005-11-01
Full Text Available The objective of this research is to compare multiple regression coefficients estimating methods with existence of multicollinearity among independent variables. The estimation methods are Ordinary Least Squares method (OLS, Restricted Least Squares method (RLS, Restricted Ridge Regression method (RRR and Restricted Liu method (RL when restrictions are true and restrictions are not true. The study used the Monte Carlo Simulation method. The experiment was repeated 1,000 times under each situation. The analyzed results of the data are demonstrated as follows. CASE 1: The restrictions are true. In all cases, RRR and RL methods have a smaller Average Mean Square Error (AMSE than OLS and RLS method, respectively. RRR method provides the smallest AMSE when the level of correlations is high and also provides the smallest AMSE for all level of correlations and all sample sizes when standard deviation is equal to 5. However, RL method provides the smallest AMSE when the level of correlations is low and middle, except in the case of standard deviation equal to 3, small sample sizes, RRR method provides the smallest AMSE.The AMSE varies with, most to least, respectively, level of correlations, standard deviation and number of independent variables but inversely with to sample size.CASE 2: The restrictions are not true.In all cases, RRR method provides the smallest AMSE, except in the case of standard deviation equal to 1 and error of restrictions equal to 5%, OLS method provides the smallest AMSE when the level of correlations is low or median and there is a large sample size, but the small sample sizes, RL method provides the smallest AMSE. In addition, when error of restrictions is increased, OLS method provides the smallest AMSE for all level, of correlations and all sample sizes, except when the level of correlations is high and sample sizes small. Moreover, the case OLS method provides the smallest AMSE, the most RLS method has a smaller AMSE than
14. [Role of medium-sized independent laboratories in control of healthcare-associated infection].
Anzai, Eiko; Fukui, Toru
2009-05-01
In 2006, the Ministry of Health and Welfare revised the regulations regarding the Medical Service Law. The amendments stipulate that all healthcare institutions are required to implement infection control programs. However, small hospitals and clinics have no clinical microbiology laboratories, whereas medium-sized hospitals have few medical technologists and the outsourcing of microbiology tests to independent laboratories is common. The decreasing number of laboratories and recent outsourcing tendency reflect the increasing commercialization, and, with it, the escalating number of commercially operating chains. Each independent laboratory is responsible for supporting activities related to the surveillance, control, and prevention of healthcare-associated infections in the associated small and medium-sized hospitals. The people responsible for infection control in these hospitals usually do not have a background in microbiology. The evaluation of communication between independent laboratory staff and hospital personnel, and rapid turnaround time of microbiology laboratory test reports are important elements ensuring the quality of independent laboratory work. With the pressures of financial constraints in the Japanese medical insurance system, the development of a cost-effective and practical protocol for quality assurance is a real dilemma.
15. Wide frequency independently controlled dual-band inkjet-printed antenna
AbuTarboush, Hattan F.
2014-01-08
A low-cost inkjet-printed multiband monopole antenna is presented. The unique advantage of the proposed antenna is the freedom to adjust and set the dual-band of the antenna independently over a wide range (148.83%). To demonstrate the independent control feature, the 2.4 and 3.4 GHz bands for the wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications are selected as an example. The measured impedance bandwidths for the 2.4 and 3.4 GHz are 15.2 and 23.7%, respectively. These dual-bands have the ability to be controlled independently between 1.1 and 7.5 GHz without affecting the other band. In addition, the proposed antenna can be assigned for different mobile and wireless applications such as GPS, PCS, GSM 1800, 1900, UMTS, and up to 5-GHz WLAN and WiMAX applications. The mechanism of independent control of each radiator through dimensional variation is discussed in detail. The antenna has a compact size of 10 × 37.3 × 0.44 mm3, leaving enough space for the driving electronics on the paper substrate. The measured results from the prototype are in good agreement with the simulated results. Owing to inkjet printing on an ordinary paper, the design is extremely light weight and highly suitable for low cost and large volume manufacturing. © The Institution of Engineering and Technology 2013.
16. Memory-guided attention: Control from multiple memory systems
Hutchinson, J. Benjamin; Turk-Browne, Nicholas B.
2012-01-01
Attention is strongly influenced by both external stimuli and internal goals. However, this useful dichotomy does not readily capture the ubiquitous and often automatic contribution of past experience stored in memory. We review recent evidence about how multiple memory systems control attention, consider how such interactions are manifested in the brain, and highlight how this framework for ‘memory-guided attention’ might help systematize previous findings and guide future research.
17. Distributed Autonomous Control of Multiple Spacecraft During Close Proximity Operations
2007-12-01
Neubauer [54][55]. 87 VII. LQR/APF CONTROL ALGORITHM APPROACH The LQR approach can be recursively applied to the multiple spacecraft close... Neubauer and Swartwout’s research [55]. It is generally possible to select a closed map over which the algorithm is stable and robust. For these...can be easily edited and transferred into video format for presentations. Modifications of camera key frames ( camera position and angle) and
18. Cycloheximide Can Induce Bax/Bak Dependent Myeloid Cell Death Independently of Multiple BH3-Only Proteins.
Katharine J Goodall
Full Text Available Apoptosis mediated by Bax or Bak is usually thought to be triggered by BH3-only members of the Bcl-2 protein family. BH3-only proteins can directly bind to and activate Bax or Bak, or indirectly activate them by binding to anti-apoptotic Bcl-2 family members, thereby relieving their inhibition of Bax and Bak. Here we describe a third way of activation of Bax/Bak dependent apoptosis that does not require triggering by multiple BH3-only proteins. In factor dependent myeloid (FDM cell lines, cycloheximide induced apoptosis by a Bax/Bak dependent mechanism, because Bax-/-Bak-/- lines were profoundly resistant, whereas FDM lines lacking one or more genes for BH3-only proteins remained highly sensitive. Addition of cycloheximide led to the rapid loss of Mcl-1 but did not affect the expression of other Bcl-2 family proteins. In support of these findings, similar results were observed by treating FDM cells with the CDK inhibitor, roscovitine. Roscovitine reduced Mcl-1 abundance and caused Bax/Bak dependent cell death, yet FDM lines lacking one or more genes for BH3-only proteins remained highly sensitive. Therefore Bax/Bak dependent apoptosis can be regulated by the abundance of anti-apoptotic Bcl-2 family members such as Mcl-1, independently of several known BH3-only proteins.
19. Robust independent modal space control of a coupled nano-positioning piezo-stage
Zhu, Wei; Yang, Fufeng; Rui, Xiaoting
2018-06-01
In order to accurately control a coupled 3-DOF nano-positioning piezo-stage, this paper designs a hybrid controller. In this controller, a hysteresis observer based on a Bouc-Wen model is established to compensate the hysteresis nonlinearity of the piezoelectric actuator first. Compared to hysteresis compensations using Preisach model and Prandt-Ishlinskii model, the compensation method using the hysteresis observer is computationally lighter. Then, based on the proposed dynamics model, by constructing the modal filter, a robust H∞ independent modal space controller is designed and utilized to decouple the piezo-stage and deal with the unmodeled dynamics, disturbance, and hysteresis compensation error. The effectiveness of the proposed controller is demonstrated experimentally. The experimental results show that the proposed controller can significantly achieve the high-precision positioning.
20. A novel quasi-master-slave control frame for PV-storage independent microgrid
Yang, Jian; Yuan, Wenbin; Sun, Yao
2018-01-01
In microgrid, photovoltaic (PV) and storage are always combined as a droop-controlled ideal source, which is not very practical. Alternatively, this paper introduces a PV-storage independent system via allocating the PV-storage separately. For this structure, a novel quasi-master-slave control...... frame is proposed without communication. Storages work as master voltage sources, and PVs operate as current controlled voltage sources (CCVS). For the slave PVs, a MPPT-based power droop control and an adaptive reactive power control are proposed. Thus, PVs can simultaneously achieve maximum energy...... is analyzed to design the physical and control parameters, such as, the minimum capacitance value of DC side, droop coefficients. Finally, simulation and experimental results are presented to verify the system effectiveness....
1. A multiple-fan active control wind tunnel for outdoor wind speed and direction simulation
Wang, Jia-Ying; Meng, Qing-Hao; Luo, Bing; Zeng, Ming
2018-03-01
This article presents a new type of active controlled multiple-fan wind tunnel. The wind tunnel consists of swivel plates and arrays of direct current fans, and the rotation speed of each fan and the shaft angle of each swivel plate can be controlled independently for simulating different kinds of outdoor wind fields. To measure the similarity between the simulated wind field and the outdoor wind field, wind speed and direction time series of two kinds of wind fields are recorded by nine two-dimensional ultrasonic anemometers, and then statistical properties of the wind signals in different time scales are analyzed based on the empirical mode decomposition. In addition, the complexity of wind speed and direction time series is also investigated using multiscale entropy and multivariate multiscale entropy. Results suggest that the simulated wind field in the multiple-fan wind tunnel has a high degree of similarity with the outdoor wind field.
2. The independent relationship between trouble controlling Facebook use, time spent on the site and distress.
Muench, Fredrick; Hayes, Marie; Kuerbis, Alexis; Shao, Sijing
2015-09-01
3. The independent relationship between trouble controlling Facebook use, time spent on the site and distress
Muench, Fredrick; Hayes, Marie; Kuerbis, Alexis; Shao, Sijing
2015-01-01
4. Phase transitions in distributed control systems with multiplicative noise
Allegra, Nicolas; Bamieh, Bassam; Mitra, Partha; Sire, Clément
2018-01-01
Contemporary technological challenges often involve many degrees of freedom in a distributed or networked setting. Three aspects are notable: the variables are usually associated with the nodes of a graph with limited communication resources, hindering centralized control; the communication is subject to noise; and the number of variables can be very large. These three aspects make tools and techniques from statistical physics particularly suitable for the performance analysis of such networked systems in the limit of many variables (analogous to the thermodynamic limit in statistical physics). Perhaps not surprisingly, phase-transition like phenomena appear in these systems, where a sharp change in performance can be observed with a smooth parameter variation, with the change becoming discontinuous or singular in the limit of infinite system size. In this paper, we analyze the so called network consensus problem, prototypical of the above considerations, that has previously been analyzed mostly in the context of additive noise. We show that qualitatively new phase-transition like phenomena appear for this problem in the presence of multiplicative noise. Depending on dimensions, and on the presence or absence of a conservation law, the system performance shows a discontinuous change at a threshold value of the multiplicative noise strength. In the absence of the conservation law, and for graph spectral dimension less than two, the multiplicative noise threshold (the stability margin of the control problem) is zero. This is reminiscent of the absence of robust controllers for certain classes of centralized control problems. Although our study involves a ‘toy’ model, we believe that the qualitative features are generic, with implications for the robust stability of distributed control systems, as well as the effect of roundoff errors and communication noise on distributed algorithms.
5. Multiple-Vehicle Longitudinal Collision Mitigation by Coordinated Brake Control
Xiao-Yun Lu
2014-01-01
Full Text Available Rear-end collision often leads to serious casualties and traffic congestion. The consequences are even worse for multiple-vehicle collision. Many previous works focused on collision warning and avoidance strategies of two consecutive vehicles based on onboard sensor detection only. This paper proposes a centralized control strategy for multiple vehicles to minimize the impact of multiple-vehicle collision based on vehicle-to-vehicle communication technique. The system is defined as a coupled group of vehicles with wireless communication capability and short following distances. The safety relationship can be represented as lower bound limit on deceleration of the first vehicle and upper bound on maximum deceleration of the last vehicle. The objective is to determine the desired deceleration for each vehicle such that the total impact energy is minimized at each time step. The impact energy is defined as the relative kinetic energy between a consecutive pair of vehicles (approaching only. Model predictive control (MPC framework is used to formulate the problem to be constrained quadratic programming. Simulations show its effectiveness on collision mitigation. The developed algorithm has the potential to be used for progressive market penetration of connected vehicles in practice.
6. Control of a dendritic neuron driven by a phase-independent stimulation
Fedaravičius, Augustinas Povilas; Cao, Maosen; Ragulskis, Minvydas
2016-01-01
A dendritic neuron model exhibits bistability under continuous weak stimulation – the oscillatory synchronized regime and the quiet regime coexist. Complex nonlinear dynamics is observed when the neuron undergoes not only phase-dependent continuous weak stimulation, but also when it is driven by an external phase-independent stimulation. In the latter case basin boundaries between the synchronized and the quiet regime become complex and fractal. Simple strategies based on control pulses are not sufficient in these circumstances, because it becomes difficult to predict the dynamics of the neuron after the application of the control pulse. Therefore, a new neural control method is proposed. Initially, a weak phase control strategy is applied until fractal basin boundaries evolve into a deterministic manifold. Consequently, a single control pulse is immediately applied and the neuron evolves into the calm state.
7. Suppression of resistive wall instabilities with distributed, independently controlled, active feedback coils
Cates, C.; Shilov, M.; Mauel, M. E.; Navratil, G. A.; Maurer, D.; Mukherjee, S.; Nadle, D.; Bialek, J.; Boozer, A.
2000-01-01
External kink instabilities are suppressed in a tokamak experiment by either (1) energizing a distributed array of independently controlled active feedback coils mounted outside a segmented resistive wall or (2) inserting a second segmented wall having much higher electrical conductivity. When the active feedback coils are off and the highly conducting wall is withdrawn, kink instabilities excited by plasma current gradients grow at a rate comparable to the magnetic diffusion rate of the resistive wall. (c) 2000 American Institute of Physics
8. Nuclear material accounting and control: Co-ordinating assistance to newly independent States
Thorstensen, S.
1995-01-01
This article outlines work under way among the IAEA, its Member States, and the Newly Independent States (NIS) relating to the establishment and development in the NIS of State Systems of Accounting and Control (SSACs) of nuclear material. It describes IAEA activities in the NIS, including fact-finding missions at technical visits, the successful attempts to find donor States providing voluntary funding and expertise, and the co-ordination of technical support between the IAEA and the donor States. 3 tabs
9. Independent programmable CAMAC crate controller based on KR580IK80A microprocessor
Kulik, O.V.; Andronov, M.A.
1986-01-01
The RTKAM-2 independent programmable CAMAC crate controller is designed for use as a remote terminal in systems for automation of physics research. The built-in 12K-byte RAM is automatically changed to 24-bit organization in exchanges with the crate dataway. A nonstandard 24-level priority-interrupt system allows an LAM-request routing to be accessed in 5.5 μsec. Communication with the base computer is through a two conductor line
10. Reliability Analysis Multiple Redundancy Controller for Nuclear Safety Systems
Son, Gwangseop; Kim, Donghoon; Son, Choulwoong
2013-01-01
This controller is configured for multiple modular redundancy (MMR) composed of dual modular redundancy (DMR) and triple modular redundancy (TMR). The architecture of MRC is briefly described, and the Markov model is developed. Based on the model, the reliability and Mean Time To Failure (MTTF) are analyzed. In this paper, the architecture of MRC for nuclear safety systems is described. The MRC is configured for multiple modular redundancy (MMR) composed of dual modular redundancy (DMR) and triple modular redundancy (TMR). Markov models for MRC architecture was developed, and then the reliability was analyzed by using the model. From the reliability analyses for the MRC, it is obtained that the failure rate of each module in the MRC should be less than 2 Χ 10 -4 /hour and the MTTF average increase rate depending on FCF increment, i. e. ΔMTTF/ΔFCF, is 4 months/0.1
11. Evaluation of multiple bio-pathological factors in colorectal adenocarcinomas: independent prognostic role of p53 and bcl-2.
Buglioni, S; D'Agnano, I; Cosimelli, M; Vasselli, S; D'Angelo, C; Tedesco, M; Zupi, G; Mottolese, M
1999-12-22
About 40% of patients with colorectal carcinoma will develop local or distant tumour recurrences. Integrated analyses of bio-pathological markers, predictive of tumour aggressiveness, may offer a more rational approach to planning adjuvant therapy. To this end, we analysed the correlation between p53 accumulation, Bcl-2 expression, DNA ploidy, cell proliferation and conventional clinico-pathological parameters by testing the prognostic significance of these variables in a series of 171 colorectal carcinoma patients with long-term follow-up. The relationships among the various bio-pathological parameters, analysed by multiple correspondence analysis, showed 2 different clinico-biological profiles. The first, characterised by p53 negativity, Bcl-2 positivity, diploidy, low percentage of cells in S-phase (%S-phase), a low Ki-67 score, is associated with Dukes' A-B stage, well differentiated tumours and lack of relapse. The second, defined by p53 positivity, Bcl-2 negativity, aneuploidy, high %S-phase and elevated Ki-67 score, correlates with Dukes' C-D stage, poorly differentiated tumours and presence of relapse. When these parameters were examined according to Kaplan-Meier's method, significantly shorter disease-free (DFS) and overall survival (OS) were also observed in patients bearing p53 positive and Bcl-2 negative tumours, in Dukes' B stage. In multivariate analysis, p53 accumulation and Bcl-2 expression emerged as independent predictors of a worse and better clinical outcome, respectively. Our results indicate that, in colorectal adenocarcinomas, a biological profile, based on the combined evaluation of p53 and Bcl-2, may be useful for identifying high risk patients to be enrolled in an adjuvant setting, mainly in an early stage of the disease. Int. J. Cancer (Pred. Oncol.) 84:545-552, 1999. Copyright 1999 Wiley-Liss, Inc.
12. Multiple levels of epigenetic control for bone biology and pathology.
Montecino, Martin; Stein, Gary; Stein, Janet; Zaidi, Kaleem; Aguilar, Rodrigo
2015-12-01
13. Ancient and novel small RNA pathways compensate for the loss of piRNAs in multiple independent nematode lineages.
Peter Sarkies
2015-02-01
Full Text Available Small RNA pathways act at the front line of defence against transposable elements across the Eukaryota. In animals, Piwi interacting small RNAs (piRNAs are a crucial arm of this defence. However, the evolutionary relationships among piRNAs and other small RNA pathways targeting transposable elements are poorly resolved. To address this question we sequenced small RNAs from multiple, diverse nematode species, producing the first phylum-wide analysis of how small RNA pathways evolve. Surprisingly, despite their prominence in Caenorhabditis elegans and closely related nematodes, piRNAs are absent in all other nematode lineages. We found that there are at least two evolutionarily distinct mechanisms that compensate for the absence of piRNAs, both involving RNA-dependent RNA polymerases (RdRPs. Whilst one pathway is unique to nematodes, the second involves Dicer-dependent RNA-directed DNA methylation, hitherto unknown in animals, and bears striking similarity to transposon-control mechanisms in fungi and plants. Our results highlight the rapid, context-dependent evolution of small RNA pathways and suggest piRNAs in animals may have replaced an ancient eukaryotic RNA-dependent RNA polymerase pathway to control transposable elements.
14. Frequency-independent radiation modes of interior sound radiation: Experimental study and global active control
Hesse, C.; Papantoni, V.; Algermissen, S.; Monner, H. P.
2017-08-01
Active control of structural sound radiation is a promising technique to overcome the poor passive acoustic isolation performance of lightweight structures in the low-frequency region. Active structural acoustic control commonly aims at the suppression of the far-field radiated sound power. This paper is concerned with the active control of sound radiation into acoustic enclosures. Experimental results of a coupled rectangular plate-fluid system under stochastic excitation are presented. The amplitudes of the frequency-independent interior radiation modes are determined in real-time using a set of structural vibration sensors, for the purpose of estimating their contribution to the acoustic potential energy in the enclosure. This approach is validated by acoustic measurements inside the cavity. Utilizing a feedback control approach, a broadband reduction of the global acoustic response inside the enclosure is achieved.
15. An Overview on SDN Architectures with Multiple Controllers
Othmane Blial
2016-01-01
Full Text Available Software-defined networking offers several benefits for networking by separating the control plane from the data plane. However, networks’ scalability, reliability, and availability remain as a big issue. Accordingly, multicontroller architectures are important for SDN-enabled networks. This paper gives a comprehensive overview of SDN multicontroller architectures. It presents SDN and its main instantiation OpenFlow. Then, it explains in detail the differences between multiple types of multicontroller architectures, like the distribution method and the communication system. Furthermore, it provides already implemented and under research examples of multicontroller architectures by describing their design, their communication process, and their performance results.
16. Enhanced adhesion of osteoblastic cells on polystyrene films by independent control of surface topography and wettability
Yang, Seung Yun [National Creative Research Center for Block Copolymer Self-Assembly, Departments of Environmental Science and Engineering and Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of); Kim, Eung-Sam [School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of); Jeon, Gumhye [National Creative Research Center for Block Copolymer Self-Assembly, Departments of Environmental Science and Engineering and Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of); Choi, Kwan Yong, E-mail: kchoi@postech.ac.kr [School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of); Department of Life Science, Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of); Kim, Jin Kon, E-mail: jkkim@postech.ac.kr [National Creative Research Center for Block Copolymer Self-Assembly, Departments of Environmental Science and Engineering and Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of)
2013-04-01
We independently controlled surface topography and wettability of polystyrene (PS) films by CF{sub 4} and oxygen plasma treatments, respectively, to evaluate the adhesion and proliferation of human fetal osteoblastic (hFOB) cells on the films. Among the CF{sub 4} plasma-treated PS films with the average surface roughness ranging from 0.9 to 70 nm, the highest adhesion of hFOB cells was observed on a PS film with roughness of ∼ 11 nm. When this film was additionally treated by oxygen plasma to provide a hydrophilic surface with a contact angle less than 10°, the proliferation of bone-forming cell was further enhanced. Thus, the plasma-based independent modification of PS film into an optimum nanotexture for human osteoblast cells could be appplied to materials used in bone tissue engineering. Highlights: ► New approach based on plasma treatment to independently control the surface topography and wettability ► The adhesion of human fetal osteoblast (hFOB) was enhanced on a surface with an average roughness of ∼ 11 nm. ► The adhesion and proliferation of hFOB was maximized when nanotextured surface became highly hydrophilic.
17. Enhanced adhesion of osteoblastic cells on polystyrene films by independent control of surface topography and wettability
Yang, Seung Yun; Kim, Eung-Sam; Jeon, Gumhye; Choi, Kwan Yong; Kim, Jin Kon
2013-01-01
We independently controlled surface topography and wettability of polystyrene (PS) films by CF 4 and oxygen plasma treatments, respectively, to evaluate the adhesion and proliferation of human fetal osteoblastic (hFOB) cells on the films. Among the CF 4 plasma-treated PS films with the average surface roughness ranging from 0.9 to 70 nm, the highest adhesion of hFOB cells was observed on a PS film with roughness of ∼ 11 nm. When this film was additionally treated by oxygen plasma to provide a hydrophilic surface with a contact angle less than 10°, the proliferation of bone-forming cell was further enhanced. Thus, the plasma-based independent modification of PS film into an optimum nanotexture for human osteoblast cells could be appplied to materials used in bone tissue engineering. Highlights: ► New approach based on plasma treatment to independently control the surface topography and wettability ► The adhesion of human fetal osteoblast (hFOB) was enhanced on a surface with an average roughness of ∼ 11 nm. ► The adhesion and proliferation of hFOB was maximized when nanotextured surface became highly hydrophilic
18. Independent control of ion current and ion impact energy onto electrodes in dual frequency plasma devices
Boyle, P C; Ellingboe, A R; Turner, M M
2004-01-01
Dual frequency capacitive discharges are designed to offer independent control of the flux and energy of ions impacting on an object immersed in a plasma. This is desirable in applications such as the processing of silicon wafers for microelectronics manufacturing. In such discharges, a low frequency component couples predominantly to the ions, while a high frequency component couples predominantly to electrons. Thus, the low frequency component controls the ion energy, while the high frequency component controls the plasma density. Clearly, this desired behaviour is not achieved for arbitrary configurations of the discharge, and in general one expects some unwanted coupling of ion flux and energy. In this paper we use computer simulations with the particle-in-cell method to show that the most important governing parameter is the ratio of the driving frequencies. If the ratio of the high and low frequencies is great enough, essentially independent control of the ion energy and flux is possible by manipulation of the high and low frequency power sources. Other operating parameters, such as pressure, discharge geometry, and absolute power, are of much less significance
19. Independent Orbiter Assessment (IOA): Assessment of the atmospheric revitalization pressure control subsystem FMEA/CIL
Saiidi, M. J.
1988-01-01
The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA effort first completed an analysis of the atmospheric Revitalization Pressure Control Subsystem (ARPCS) hardware, generating draft failure modes and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The IOA results were then compared to the NASA FMEA/CIL proposed Post 51-L updates based upon the CCB/PRCB presentations and an informal criticality summary listing. A discussion of each discrepancy from the comparison is provided through additional analysis as required. These discrepancies were flagged as issues, and recommendations were made based on the FMEA data available at the time. This report documents the results of that comparison for the Orbiter ARPCS hardware.
20. Enhanced adhesion of osteoblastic cells on polystyrene films by independent control of surface topography and wettability.
Yang, Seung Yun; Kim, Eung-Sam; Jeon, Gumhye; Choi, Kwan Yong; Kim, Jin Kon
2013-04-01
We independently controlled surface topography and wettability of polystyrene (PS) films by CF4 and oxygen plasma treatments, respectively, to evaluate the adhesion and proliferation of human fetal osteoblastic (hFOB) cells on the films. Among the CF4 plasma-treated PS films with the average surface roughness ranging from 0.9 to 70 nm, the highest adhesion of hFOB cells was observed on a PS film with roughness of ~11 nm. When this film was additionally treated by oxygen plasma to provide a hydrophilic surface with a contact angle less than 10°, the proliferation of bone-forming cell was further enhanced. Thus, the plasma-based independent modification of PS film into an optimum nanotexture for human osteoblast cells could be appplied to materials used in bone tissue engineering. Copyright © 2012 Elsevier B.V. All rights reserved.
1. Optically controlled multiple switching operations of DNA biopolymer devices
Hung, Chao-You; Tu, Waan-Ting; Lin, Yi-Tzu; Fruk, Ljiljana; Hung, Yu-Chueh
2015-01-01
We present optically tunable operations of deoxyribonucleic acid (DNA) biopolymer devices, where a single high-resistance state, write-once read-many-times memory state, write-read-erase memory state, and single low-resistance state can be achieved by controlling UV irradiation time. The device is a simple sandwich structure with a spin-coated DNA biopolymer layer sandwiched by two electrodes. Upon irradiation, the electrical properties of the device are adjusted owing to a phototriggered synthesis of silver nanoparticles in DNA biopolymer, giving rise to multiple switching scenarios. This technique, distinct from the strategy of doping of pre-formed nanoparticles, enables a post-film fabrication process for achieving optically controlled memory device operations, which provides a more versatile platform to fabricate organic memory and optoelectronic devices
2. Optically controlled multiple switching operations of DNA biopolymer devices
Hung, Chao-You; Tu, Waan-Ting; Lin, Yi-Tzu [Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Fruk, Ljiljana [Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA (United Kingdom); Hung, Yu-Chueh, E-mail: ychung@ee.nthu.edu.tw [Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)
2015-12-21
We present optically tunable operations of deoxyribonucleic acid (DNA) biopolymer devices, where a single high-resistance state, write-once read-many-times memory state, write-read-erase memory state, and single low-resistance state can be achieved by controlling UV irradiation time. The device is a simple sandwich structure with a spin-coated DNA biopolymer layer sandwiched by two electrodes. Upon irradiation, the electrical properties of the device are adjusted owing to a phototriggered synthesis of silver nanoparticles in DNA biopolymer, giving rise to multiple switching scenarios. This technique, distinct from the strategy of doping of pre-formed nanoparticles, enables a post-film fabrication process for achieving optically controlled memory device operations, which provides a more versatile platform to fabricate organic memory and optoelectronic devices.
3. Recent independent emergence of multiple multidrug-resistant Serratia marcescens clones within the United Kingdom and Ireland.
Moradigaravand, Danesh; Boinett, Christine J; Martin, Veronique; Peacock, Sharon J; Parkhill, Julian
2016-08-01
Serratia marcescens, a member of the Enterobacteriaceae family, is a Gram-negative bacterium responsible for a wide range of nosocomial infections. The emergence of multidrug-resistant strains is an increasing danger to public health. To design effective means to control the dissemination of S. marcescens, an in-depth analysis of the population structure and variation is required. Utilizing whole-genome sequencing, we characterized the population structure and variation, as well as the antimicrobial resistance determinants, of a systematic collection of antimicrobial-resistant S. marcescens associated with bloodstream infections in hospitals across the United Kingdom and Ireland between 2001 and 2011. Our results show that S. marcescens is a diverse species with a high level of genomic variation. However, the collection was largely composed of a limited number of clones that emerged from this diverse background within the past few decades. We identified potential recent transmissions of these clones, within and between hospitals, and showed that they have acquired antimicrobial resistance determinants for different beta-lactams, ciprofloxacin, and tetracyclines on multiple occasions. The expansion of these multidrug-resistant clones suggests that the treatment of S. marcescens infections will become increasingly difficult in the future. © 2016 Moradigaravand et al.; Published by Cold Spring Harbor Laboratory Press.
4. Independent genetic control of maize (Zea mays L.) kernel weight determination and its phenotypic plasticity.
2014-08-01
Maize kernel weight (KW) is associated with the duration of the grain-filling period (GFD) and the rate of kernel biomass accumulation (KGR). It is also related to the dynamics of water and hence is physiologically linked to the maximum kernel water content (MWC), kernel desiccation rate (KDR), and moisture concentration at physiological maturity (MCPM). This work proposed that principles of phenotypic plasticity can help to consolidated the understanding of the environmental modulation and genetic control of these traits. For that purpose, a maize population of 245 recombinant inbred lines (RILs) was grown under different environmental conditions. Trait plasticity was calculated as the ratio of the variance of each RIL to the overall phenotypic variance of the population of RILs. This work found a hierarchy of plasticities: KDR ≈ GFD > MCPM > KGR > KW > MWC. There was no phenotypic and genetic correlation between traits per se and trait plasticities. MWC, the trait with the lowest plasticity, was the exception because common quantitative trait loci were found for the trait and its plasticity. Independent genetic control of a trait per se and genetic control of its plasticity is a condition for the independent evolution of traits and their plasticities. This allows breeders potentially to select for high or low plasticity in combination with high or low values of economically relevant traits. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.
5. Independently controlled wing stroke patterns in the fruit fly Drosophila melanogaster.
Soma Chakraborty
Full Text Available Flies achieve supreme flight maneuverability through a small set of miniscule steering muscles attached to the wing base. The fast flight maneuvers arise from precisely timed activation of the steering muscles and the resulting subtle modulation of the wing stroke. In addition, slower modulation of wing kinematics arises from changes in the activity of indirect flight muscles in the thorax. We investigated if these modulations can be described as a superposition of a limited number of elementary deformations of the wing stroke that are under independent physiological control. Using a high-speed computer vision system, we recorded the wing motion of tethered flying fruit flies for up to 12,000 consecutive wing strokes at a sampling rate of 6250 Hz. We then decomposed the joint motion pattern of both wings into components that had the minimal mutual information (a measure of statistical dependence. In 100 flight segments measured from 10 individual flies, we identified 7 distinct types of frequently occurring least-dependent components, each defining a kinematic pattern (a specific deformation of the wing stroke and the sequence of its activation from cycle to cycle. Two of these stroke deformations can be associated with the control of yaw torque and total flight force, respectively. A third deformation involves a change in the downstroke-to-upstroke duration ratio, which is expected to alter the pitch torque. A fourth kinematic pattern consists in the alteration of stroke amplitude with a period of 2 wingbeat cycles, extending for dozens of cycles. Our analysis indicates that these four elementary kinematic patterns can be activated mutually independently, and occur both in isolation and in linear superposition. The results strengthen the available evidence for independent control of yaw torque, pitch torque, and total flight force. Our computational method facilitates systematic identification of novel patterns in large kinematic datasets.
6. Independently controlled wing stroke patterns in the fruit fly Drosophila melanogaster.
Chakraborty, Soma; Bartussek, Jan; Fry, Steven N; Zapotocky, Martin
2015-01-01
Flies achieve supreme flight maneuverability through a small set of miniscule steering muscles attached to the wing base. The fast flight maneuvers arise from precisely timed activation of the steering muscles and the resulting subtle modulation of the wing stroke. In addition, slower modulation of wing kinematics arises from changes in the activity of indirect flight muscles in the thorax. We investigated if these modulations can be described as a superposition of a limited number of elementary deformations of the wing stroke that are under independent physiological control. Using a high-speed computer vision system, we recorded the wing motion of tethered flying fruit flies for up to 12,000 consecutive wing strokes at a sampling rate of 6250 Hz. We then decomposed the joint motion pattern of both wings into components that had the minimal mutual information (a measure of statistical dependence). In 100 flight segments measured from 10 individual flies, we identified 7 distinct types of frequently occurring least-dependent components, each defining a kinematic pattern (a specific deformation of the wing stroke and the sequence of its activation from cycle to cycle). Two of these stroke deformations can be associated with the control of yaw torque and total flight force, respectively. A third deformation involves a change in the downstroke-to-upstroke duration ratio, which is expected to alter the pitch torque. A fourth kinematic pattern consists in the alteration of stroke amplitude with a period of 2 wingbeat cycles, extending for dozens of cycles. Our analysis indicates that these four elementary kinematic patterns can be activated mutually independently, and occur both in isolation and in linear superposition. The results strengthen the available evidence for independent control of yaw torque, pitch torque, and total flight force. Our computational method facilitates systematic identification of novel patterns in large kinematic datasets.
7. Microprocessor-based control for independently-phased RF linac cavities
Dawson, J.W.
1979-01-01
A microprocessor based system has been built to control the RF amplifiers associated with independently phased linac cavities. The system has an 8080A at each amplifier station, together with associated ROM, RAM, I/O, etc. At a central NOVA 3 computer an additional 8080A system is incorporated in the interface to the NOVA I/O bus. The NOVA interface is connected by a bus of eighteen twisted pairs to each amplifier station, providing bilateral transmission between each station and the NOVA. The system architecture, bus protocol, and operating characteristics are described
8. Multiple Acid Sensors Control Helicobacter pylori Colonization of the Stomach.
Huang, Julie Y; Goers Sweeney, Emily; Guillemin, Karen; Amieva, Manuel R
2017-01-01
Helicobacter pylori's ability to respond to environmental cues in the stomach is integral to its survival. By directly visualizing H. pylori swimming behavior when encountering a microscopic gradient consisting of the repellent acid and attractant urea, we found that H. pylori is able to simultaneously detect both signals, and its response depends on the magnitudes of the individual signals. By testing for the bacteria's response to a pure acid gradient, we discovered that the chemoreceptors TlpA and TlpD are each independent acid sensors. They enable H. pylori to respond to and escape from increases in hydrogen ion concentration near 100 nanomolar. TlpD also mediates attraction to basic pH, a response dampened by another chemoreceptor TlpB. H. pylori mutants lacking both TlpA and TlpD (ΔtlpAD) are unable to sense acid and are defective in establishing colonization in the murine stomach. However, blocking acid production in the stomach with omeprazole rescues ΔtlpAD's colonization defect. We used 3D confocal microscopy to determine how acid blockade affects the distribution of H. pylori in the stomach. We found that stomach acid controls not only the overall bacterial density, but also the microscopic distribution of bacteria that colonize the epithelium deep in the gastric glands. In omeprazole treated animals, bacterial abundance is increased in the antral glands, and gland colonization range is extended to the corpus. Our findings indicate that H. pylori has evolved at least two independent receptors capable of detecting acid gradients, allowing not only survival in the stomach, but also controlling the interaction of the bacteria with the epithelium.
9. Genetic algorithm–based varying parameter linear quadratic regulator control for four-wheel independent steering vehicle
Linlin Gao
2015-11-01
Full Text Available From the perspective of vehicle dynamics, the four-wheel independent steering vehicle dynamics stability control method is studied, and a four-wheel independent steering varying parameter linear quadratic regulator control system is proposed with the help of expert control method. In the article, a four-wheel independent steering linear quadratic regulator controller for model following purpose is designed first. Then, by analyzing the four-wheel independent steering vehicle dynamic characteristics and the influence of linear quadratic regulator control parameters on control performance, a linear quadratic regulator control parameter adjustment strategy based on vehicle steering state is proposed to achieve the adaptive adjustment of linear quadratic regulator control parameters. In addition, to further improve the control performance, the proposed varying parameter linear quadratic regulator control system is optimized by genetic algorithm. Finally, simulation studies have been conducted by applying the proposed control system to the 8-degree-of-freedom four-wheel independent steering vehicle dynamics model. The simulation results indicate that the proposed control system has better performance and robustness and can effectively improve the stability and steering safety of the four-wheel independent steering vehicle.
10. Protocol for the effect evaluation of independent medical evaluation after six months sick leave: a randomized controlled trial of independent medical evaluation versus treatment as usual in Norway.
Husabo, Elisabeth; Monstad, Karin; Holmås, Tor Helge; Oyeflaten, Irene; Werner, Erik L; Maeland, Silje
2017-06-14
It has been discussed whether the relationship between a patient on sick leave and his/her general practitioner (GP) is too close, as this may hinder the GP's objective evaluation of need for sick leave. Independent medical evaluation involves an independent physician consulting the patient. This could lead to new perspectives on sick leave and how to follow-up the patient. The current study is a randomized controlled trial in a Norwegian primary care context, involving an effect evaluation, a cost/benefit analysis, and a qualitative evaluation. Independent medical evaluation will be compared to treatment as usual, i.e., the physicians' and social insurance agencies' current management of long-term sick-listed patients. Individuals aged 18-65 years, sick listed by their GP and on full or partial sick leave for the past 6 months in Hordaland county will be included. Exclusion criteria are pregnancy, cancer, dementia or an ICD-10 diagnosis. A total sample of 3800 will be randomly assigned to either independent medical evaluation or treatment as usual. Official register data will be used to measure the primary outcome; change in sickness benefits at 7, 9 and 12 months. Sick listed in other counties will serve as a second control group, if appropriate under the "common trend" assumption. The Norwegian effect evaluation of independent medical evaluation after 6 months sick leave is a large randomized controlled trial, and the first of its kind, to evaluate this type of intervention as a means of getting people back to work after long-term sickness absence. ClinicalTrials.gov NCT02524392 . Registered June 23, 2015.
11. Protocol for the effect evaluation of independent medical evaluation after six months sick leave: a randomized controlled trial of independent medical evaluation versus treatment as usual in Norway
Elisabeth Husabo
2017-06-01
Full Text Available Abstract Background It has been discussed whether the relationship between a patient on sick leave and his/her general practitioner (GP is too close, as this may hinder the GP’s objective evaluation of need for sick leave. Independent medical evaluation involves an independent physician consulting the patient. This could lead to new perspectives on sick leave and how to follow-up the patient. Methods/design The current study is a randomized controlled trial in a Norwegian primary care context, involving an effect evaluation, a cost/benefit analysis, and a qualitative evaluation. Independent medical evaluation will be compared to treatment as usual, i.e., the physicians’ and social insurance agencies’ current management of long-term sick-listed patients. Individuals aged 18–65 years, sick listed by their GP and on full or partial sick leave for the past 6 months in Hordaland county will be included. Exclusion criteria are pregnancy, cancer, dementia or an ICD-10 diagnosis. A total sample of 3800 will be randomly assigned to either independent medical evaluation or treatment as usual. Official register data will be used to measure the primary outcome; change in sickness benefits at 7, 9 and 12 months. Sick listed in other counties will serve as a second control group, if appropriate under the “common trend” assumption. Discussion The Norwegian effect evaluation of independent medical evaluation after 6 months sick leave is a large randomized controlled trial, and the first of its kind, to evaluate this type of intervention as a means of getting people back to work after long-term sickness absence. Trial registration ClinicalTrials.gov NCT02524392 . Registered June 23, 2015.
12. Mission control of multiple unmanned aerial vehicles: a workload analysis.
Dixon, Stephen R; Wickens, Christopher D; Chang, Dervon
2005-01-01
13. Independently variable phase and stroke control for a double acting Stirling engine
Berchowitz, David M.
1983-01-01
A phase and stroke control apparatus for the pistons of a Stirling engine includes a ring on the end of each piston rod in which a pair of eccentrics is arranged in series, torque transmitting relationship. The outer eccentric is rotatably mounted in the ring and is rotated by the orbiting ring; the inner eccentric is mounted on an output shaft. The two eccentrics are mounted for rotation together within the ring during normal operation. A device is provided for rotating one eccentric with respect to another to change the effective eccentricity of the pair of eccentrics. A separately controlled phase adjustment is provided to null the phase change introduced by the change in the orientation of the outer eccentric, and also to enable the phase of the pistons to be changed independently of the stroke change.
14. Paravascular pathways contribute to vasculitis and neuroinflammation after subarachnoid hemorrhage independently of glymphatic control.
Luo, C; Yao, X; Li, J; He, B; Liu, Q; Ren, H; Liang, F; Li, M; Lin, H; Peng, J; Yuan, T F; Pei, Z; Su, H
2016-03-31
Subarachnoid hemorrhage (SAH) is a devastating disease with high mortality. The mechanisms underlying its pathological complications have not been fully identified. Here, we investigate the potential involvement of the glymphatic system in the neuropathology of SAH. We demonstrate that blood components rapidly enter the paravascular space following SAH and penetrate into the perivascular parenchyma throughout the brain, causing disastrous events such as cerebral vasospasm, delayed cerebral ischemia, microcirculation dysfunction and widespread perivascular neuroinflammation. Clearance of the paravascular pathway with tissue-type plasminogen activator ameliorates the behavioral deficits and alleviates histological injury of SAH. Interestingly, AQP4(-/-) mice showed no improvements in neurological deficits and neuroinflammation at day 7 after SAH compared with WT control mice. In conclusion, our study proves that the paravascular pathway dynamically mediates the pathological complications following acute SAH independently of glymphatic control.
15. Opium could be considered an independent risk factor for lung cancer: a case-control study.
Masjedi, Mohammad Reza; Naghan, Parisa Adimi; Taslimi, Shervin; Yousefifard, Mahmoud; Ebrahimi, Seyyed Meisam; Khosravi, Adnan; Karimi, Shirin; Hosseini, Mostafa; Mortaz, Esmaeil
2013-01-01
Lung cancer is the leading cause of cancer-related death worldwide, and half of all incident lung cancers are believed to occur in the developing countries, including Iran. We investigated the association of opium with the risk of lung cancer in a case-control study. We enrolled 242 cases and 484 matched controls in this study. A questionnaire was developed, containing questions on basic demographic characteristics, as well as lifelong history of smoking cigarettes, exposure to passive smoking, opium use and alcohol consumption. For smoking cigarettes and opium and also oral opium intake frequency, duration and cumulative use were categorized into three groups: no use, low use and high use. Conditional logistic regression was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs). Multivariate analysis in men showed that after adjusting for the effect of ethnicity, education and pack years of smoking cigarettes, smoking opium remained as a significant independent risk factor with an OR of 3.1 (95% CI 1.2-8.1). In addition, concomitant heavy smoking of cigarettes and opium dramatically increased the risk of lung cancer to an OR of 35.0 (95% CI 11.4-107.9). This study demonstrated that smoking opium is associated with a high risk of lung cancer as an independent risk factor. Copyright © 2012 S. Karger AG, Basel.
16. Prickle isoforms control the direction of tissue polarity by microtubule independent and dependent mechanisms
Katherine A. Sharp
2016-03-01
Full Text Available Planar cell polarity signaling directs the polarization of cells within the plane of many epithelia. While these tissues exhibit asymmetric localization of a set of core module proteins, in Drosophila, more than one mechanism links the direction of core module polarization to the tissue axes. One signaling system establishes a polarity bias in the parallel, apical microtubules upon which vesicles containing core proteins traffic. Swapping expression of the differentially expressed Prickle isoforms, Prickle and Spiny-legs, reverses the direction of core module polarization. Studies in the proximal wing and the anterior abdomen indicated that this results from their differential control of microtubule polarity. Prickle and Spiny-legs also control the direction of polarization in the distal wing (D-wing and the posterior abdomen (P-abd. We report here that this occurs without affecting microtubule polarity in these tissues. The direction of polarity in the D-wing is therefore likely determined by a novel mechanism independent of microtubule polarity. In the P-abd, Prickle and Spiny-legs interpret at least two directional cues through a microtubule-polarity-independent mechanism.
17. Decentralized Formation Flying Control in a Multiple-Team Hierarchy
Mueller, Joseph .; Thomas, Stephanie J.
2005-01-01
This paper presents the prototype of a system that addresses these objectives-a decentralized guidance and control system that is distributed across spacecraft using a multiple-team framework. The objective is to divide large clusters into teams of manageable size, so that the communication and computational demands driven by N decentralized units are related to the number of satellites in a team rather than the entire cluster. The system is designed to provide a high-level of autonomy, to support clusters with large numbers of satellites, to enable the number of spacecraft in the cluster to change post-launch, and to provide for on-orbit software modification. The distributed guidance and control system will be implemented in an object-oriented style using MANTA (Messaging Architecture for Networking and Threaded Applications). In this architecture, tasks may be remotely added, removed or replaced post-launch to increase mission flexibility and robustness. This built-in adaptability will allow software modifications to be made on-orbit in a robust manner. The prototype system, which is implemented in MATLAB, emulates the object-oriented and message-passing features of the MANTA software. In this paper, the multiple-team organization of the cluster is described, and the modular software architecture is presented. The relative dynamics in eccentric reference orbits is reviewed, and families of periodic, relative trajectories are identified, expressed as sets of static geometric parameters. The guidance law design is presented, and an example reconfiguration scenario is used to illustrate the distributed process of assigning geometric goals to the cluster. Next, a decentralized maneuver planning approach is presented that utilizes linear-programming methods to enact reconfiguration and coarse formation keeping maneuvers. Finally, a method for performing online collision avoidance is discussed, and an example is provided to gauge its performance.
18. Control area readiness audit report of the Independent Electricity Market Operator (IMO)
Gladish, L.A.; Campoli, G.; Le, Q.; Farrokhpay, S.; Kirby, B.; Penwell, C.; Weaver, S.; Vicini, D.; Wells, M.
2004-01-01
The Independent Electricity Market Operator (IMO) is a control area authority that is responsible for the safe and reliable operation of its portion of the bulk electric system in cooperation with neighbouring control areas. This audit by the North American Electric Reliability Council (NERC) reviewed the readiness of Ontario's IMO to meets its responsibilities as a control area operator. NERC recommended specific actions to correct the deficiencies that resulted in the blackout in southeastern Ontario and northeastern United States on August 14, 2003. Initiatives to strengthen compliance with existing standards were also suggested along with longer-term technical initiatives to prevent or mitigate the impacts of cascading blackouts in the future. The audit process included: a self-assessment questionnaire to the control area being audited; a questionnaire to neighbouring control areas; a questionnaire to the reliability coordinator and an on-site audit by a selected audit team. The following issues were reviewed: criteria and compliance, authority, responsibilities in the planning time frame, real time monitoring, system restoration, delegation of reliability coordinator functions, outage coordination, transmission and generation relaying, energy emergency plan, operating policy, line clearances, and nuclear power plant requirements. It was concluded that the IMO has the necessary plans, procedures, processes, tools and trained personnel to respond to emergency events. The audit did not find any major operational problems, but offered a few recommendations for improvement. tabs
19. Damping-tunable energy-harvesting vehicle damper with multiple controlled generators: Design, modeling and experiments
Xie, Longhan; Li, Jiehong; Li, Xiaodong; Huang, Ledeng; Cai, Siqi
2018-01-01
Hydraulic dampers are used to decrease the vibration of a vehicle, where vibration energy is dissipated as heat. In addition to resulting in energy waste, the damping coefficient in hydraulic dampers cannot be changed during operation. In this paper, an energy-harvesting vehicle damper was proposed to replace traditional hydraulic dampers. The goal is not only to recover kinetic energy from suspension vibration but also to change the damping coefficient during operation according to road conditions. The energy-harvesting damper consists of multiple generators that are independently controlled by switches. One of these generators connects to a tunable resistor for fine tuning the damping coefficient, while the other generators are connected to a control and rectifying circuit, each of which both regenerates electricity and provides a constant damping coefficient. A mathematical model was built to investigate the performance of the energy-harvesting damper. By controlling the number of switched-on generators and adjusting the value of the external tunable resistor, the damping can be fine tuned according to the requirement. In addition to the capability of damping tuning, the multiple controlled generators can output a significant amount of electricity. A prototype was built to test the energy-harvesting damper design. Experiments on an MTS testing system were conducted, with results that validated the theoretical analysis. Experiments show that changing the number of switched-on generators can obviously tune the damping coefficient of the damper and simultaneously produce considerable electricity.
20. Definition and dynamic control of a continuous chromatography process independent of cell culture titer and impurities.
Chmielowski, Rebecca A; Mathiasson, Linda; Blom, Hans; Go, Daniel; Ehring, Hanno; Khan, Heera; Li, Hong; Cutler, Collette; Lacki, Karol; Tugcu, Nihal; Roush, David
2017-12-01
Advances in cell culture technology have enabled the production of antibody titers upwards of 30g/L. These highly productive cell culture systems can potentially lead to productivity bottlenecks in downstream purification due to lower column loadings, especially in the primary capture chromatography step. Alternative chromatography solutions to help remedy this bottleneck include the utilization of continuous processing systems such as periodic counter-current chromatography (PCC). Recent studies have provided methods to optimize and improve the design of PCC for cell culture titers up to about 3g/L. This paper defines a continuous loading strategy for PCC that is independent of cell culture background and encompasses cell culture titers up to about 31g/L. Initial experimentation showed a challenge with determining a difference in change in UV280nm signal (ie. ΔUV) between cell culture feed and monoclonal antibody (mAb) concentration. Further investigation revealed UV280nm absorbance of the cell culture feedstock without antibody was outside of the linear range of detection for a given cell pathlength. Additional experimentation showed the difference in ΔUV for various cell culture feeds can be either theoretically predicted by Beer's Law given a known absorbance of the media background and impurities or experimentally determined using various UV280nm cell pathlengths. Based on these results, a 0.35mm pathlength at UV280nm was chosen for dynamic control to overcome the background signal. The pore diffusion model showed good agreement with the experimental frontal analysis data, which resulted in definition of a ΔUV setpoint range between 20 and 70% for 3C-PCC experiments. Product quality of the elution pools was acceptable between various cell culture feeds and titers up to about 41g/L. Results indicated the following ΔUV setpoints to achieve robust dynamic control and maintain 3C-PCC yield: ∼20-45% for titers greater than 10g/L depending on UV absorbance of
1. Independent control of matrix adhesiveness and stiffness within a 3D self-assembling peptide hydrogel.
Hogrebe, Nathaniel J; Reinhardt, James W; Tram, Nguyen K; Debski, Anna C; Agarwal, Gunjan; Reilly, Matthew A; Gooch, Keith J
2018-04-01
A cell's insoluble microenvironment has increasingly been shown to exert influence on its function. In particular, matrix stiffness and adhesiveness strongly impact behaviors such as cell spreading and differentiation, but materials that allow for independent control of these parameters within a fibrous, stromal-like microenvironment are very limited. In the current work, we devise a self-assembling peptide (SAP) system that facilitates user-friendly control of matrix stiffness and RGD (Arg-Gly-Asp) concentration within a hydrogel possessing a microarchitecture similar to stromal extracellular matrix. In this system, the RGD-modified SAP sequence KFE-RGD and the scrambled sequence KFE-RDG can be directly swapped for one another to change RGD concentration at a given matrix stiffness and total peptide concentration. Stiffness is controlled by altering total peptide concentration, and the unmodified base peptide KFE-8 can be included to further increase this stiffness range due to its higher modulus. With this tunable system, we demonstrate that human mesenchymal stem cell morphology and differentiation are influenced by both gel stiffness and the presence of functional cell binding sites in 3D culture. Specifically, cells 24 hours after encapsulation were only able to spread out in stiffer matrices containing KFE-RGD. Upon addition of soluble adipogenic factors, soft gels facilitated the greatest adipogenesis as determined by the presence of lipid vacuoles and PPARγ-2 expression, while increasing KFE-RGD concentration at a given stiffness had a negative effect on adipogenesis. This three-component hydrogel system thus allows for systematic investigation of matrix stiffness and RGD concentration on cell behavior within a fibrous, three-dimensional matrix. Physical cues from a cell's surrounding environment-such as the density of cell binding sites and the stiffness of the surrounding material-are increasingly being recognized as key regulators of cell function
2. Torque Distribution Algorithm for an Independently Driven Electric Vehicle Using a Fuzzy Control Method
Jinhyun Park
2015-08-01
Full Text Available The in-wheel electric vehicle is expected to be a popular next-generation vehicle because an in-wheel system can simplify the powertrain and improve driving performance. In addition, it also has an advantage in that it maximizes driving efficiency through independent torque control considering the motor efficiency. However, there is an instability problem if only the driving torque is controlled in consideration of only the motor efficiency. In this paper, integrated torque distribution strategies are proposed to overcome these problems. The control algorithm consists of various strategies for optimizing driving efficiency, satisfying driver demands, and considering tire slip and vehicle cornering. Fuzzy logic is used to determine the appropriate timing of intervention for each distribution strategy. A performance simulator for in-wheel electric vehicles was developed by using MATLAB/Simulink and CarSim to validate the control strategies. From simulation results under complex driving conditions, the proposed algorithm was verified to improve both the driving stability and fuel economy of the in-wheel vehicle.
3. Independent control of the shape and composition of ionic nanocrystals through sequential cation exchange reactions
Luther, Joseph Matthew; Zheng, Haimei; Sadtler, Bryce; Alivisatos, A. Paul
2009-07-06
Size- and shape-controlled nanocrystal growth is intensely researched for applications including electro-optic, catalytic, and medical devices. Chemical transformations such as cation exchange overcome the limitation of traditional colloidal synthesis, where the nanocrystal shape often reflects the inherent symmetry of the underlying lattice. Here we show that nanocrystals, with established synthetic protocols for high monodispersity, can be templates for independent composition control. Specifically, controlled interconversion between wurtzite CdS, chalcocite Cu2S, and rock salt PbS occurs while preserving the anisotropic dimensions unique to the as-synthesized materials. Sequential exchange reactions between the three sulfide compositions are driven by the disparate solubilites of the metal ion exchange pair in specific coordinating molecules. Starting with CdS, highly anisotropic PbS nanorods are created, which serve as an important material for studying strong 2-dimensional quantum confinement, as well as for optoelectronic applications. Furthermore, interesting nanoheterostructures of CdS|PbS are obtained by precise control over ion insertion and removal.
4. Independent and Social Living Skills Training for People with Schizophrenia in Iran: a Randomized Controlled Trial
Ashraf Karbalaee-Nouri
2015-09-01
Full Text Available Objectives: Schizophrenia is responsible for a significant proportion of burden of mental diseases in Iran. Lack of a follow-up system has resulted in the repeated hospitalizations. In this study it is hypothesized that standardized living skills training delivered to participants with schizophrenia in outpatient and inpatient centers can be effective compared to a control group (with occupational therapy in reducing psychopathology severity and increasing quality of life. Methods: This is a multi-centered parallel group randomized controlled trial in Iran and it is single-blinded. Eligible participants are randomly allocated into two groups in a 1:1 ratio. Participants are assigned by stratified balanced block randomization method. The trial is conducted in the cities of Tehran and Mashhad. Its aim is to recruit 160 clients with schizophrenia. The intervention for the experimental group is social living skills training. The intervention for the control group is occupational therapy. The intervention for both groups is conducted in 90 to 120-minute group sessions. Results: The primary outcome of the study would be a decrease in psychopathology severity, an improvement in participants' quality of life, and reduction in family burden will be followed for 6 months. Discussion: This paper presents a protocol for a randomized controlled trial of independent and social living skills training intervention delivered to participants with schizophrenia. If this intervention is effective, it could be scaled up to be developing for policymaking and improving outcomes for schizophrenic participants and their families in Iran.
5. Controlling energy transfer between multiple dopants within a single nanoparticle
DiMaio, Jeffrey R.; Sabatier, Clément; Kokuoz, Baris; Ballato, John
2008-01-01
Complex core-shell architectures are implemented within LaF3 nanoparticles to allow for a tailored degree of energy transfer (ET) between different rare earth dopants. By constraining specific dopants to individual shells, their relative distance to one another can be carefully controlled. Core-shell LaF3 nanoparticles doped with Tb3+ and Eu3+ and consisting of up to four layers were synthesized with an outer diameter of ≈10 nm. It is found that by varying the thicknesses of an undoped layer between a Tb3+-doped layer and a Eu3+-doped layer, the degree of ET can be engineered to allow for zero, partial, or total ET from a donor ion to an acceptor ion. More specifically, the ratio of the intensities of the 541-nm Tb3+ and 590 nm Eu3+ peaks was tailored from core-shell configuration that restricts ET is used. Beyond simply controlling ET, which can be limiting when designing materials for optical applications, this approach can be used to obtain truly engineered spectral features from nanoparticles and composites made from them. Further, it allows for a single excitation source to yield multiple discrete emissions from numerous lanthanide dopants that heretofore would have been quenched in a more conventional active optical material. PMID:18250307
6. Independent Attention Mechanisms Control the Activation of Tactile and Visual Working Memory Representations.
Katus, Tobias; Eimer, Martin
2018-05-01
7. Multiple independent loci at chromosome 15q25.1 affect smoking quantity: a meta-analysis and comparison with lung cancer and COPD.
Nancy L Saccone
2010-08-01
Full Text Available Recently, genetic association findings for nicotine dependence, smoking behavior, and smoking-related diseases converged to implicate the chromosome 15q25.1 region, which includes the CHRNA5-CHRNA3-CHRNB4 cholinergic nicotinic receptor subunit genes. In particular, association with the nonsynonymous CHRNA5 SNP rs16969968 and correlates has been replicated in several independent studies. Extensive genotyping of this region has suggested additional statistically distinct signals for nicotine dependence, tagged by rs578776 and rs588765. One goal of the Consortium for the Genetic Analysis of Smoking Phenotypes (CGASP is to elucidate the associations among these markers and dichotomous smoking quantity (heavy versus light smoking, lung cancer, and chronic obstructive pulmonary disease (COPD. We performed a meta-analysis across 34 datasets of European-ancestry subjects, including 38,617 smokers who were assessed for cigarettes-per-day, 7,700 lung cancer cases and 5,914 lung-cancer-free controls (all smokers, and 2,614 COPD cases and 3,568 COPD-free controls (all smokers. We demonstrate statistically independent associations of rs16969968 and rs588765 with smoking (mutually adjusted p-values<10(-35 and <10(-8 respectively. Because the risk alleles at these loci are negatively correlated, their association with smoking is stronger in the joint model than when each SNP is analyzed alone. Rs578776 also demonstrates association with smoking after adjustment for rs16969968 (p<10(-6. In models adjusting for cigarettes-per-day, we confirm the association between rs16969968 and lung cancer (p<10(-20 and observe a nominally significant association with COPD (p = 0.01; the other loci are not significantly associated with either lung cancer or COPD after adjusting for rs16969968. This study provides strong evidence that multiple statistically distinct loci in this region affect smoking behavior. This study is also the first report of association between rs588765
8. Characterization of UAV Performance and Development of a Formation Flight Controller for Multiple Small UAVS
McCarthy, Patrick A
2006-01-01
... (UAV). One area of particular interest is using multiple small UAVs cooperatively to improve mission efficiency, as well as perform missions that couldn't be performed using vehicles independently...
9. Fine-scale mapping of 8q24 locus identifies multiple independent risk variants for breast cancer
J. Shi (Jiajun); Zhang, Y. (Yanfeng); W. Zheng (Wei); K. Michailidou (Kyriaki); M. Ghoussaini (Maya); M.K. Bolla (Manjeet K.); Wang, Q. (Qin); J. Dennis (Joe); Lush, M. (Michael); R.L. Milne (Roger); X.-O. Shu (Xiao-Ou); J. Beesley (Jonathan); S. Kar (Siddhartha); I.L. Andrulis (Irene); H. Anton-Culver (Hoda); Arndt, V. (Volker); M.W. Beckmann (Matthias); Z. Zhao (Zhiguo); Guo, X. (Xingyi); J. Benítez (Javier); A. Beeghly-Fadiel (Alicia); W.J. Blot (William); N.V. Bogdanova (Natalia); S.E. Bojesen (Stig); H. Brauch (Hiltrud); H. Brenner (Hermann); L.A. Brinton (Louise); A. Broeks (Annegien); T. Brüning (Thomas); B. Burwinkel (Barbara); H. Cai (Hui); S. Canisius (Sander); J. Chang-Claude (Jenny); Choi, J.-Y. (Ji-Yeob); F.J. Couch (Fergus); A. Cox (Angela); S.S. Cross (Simon); K. Czene (Kamila); H. Darabi (Hatef); P. Devilee (Peter); A. Droit (Arnaud); T. Dörk (Thilo); P.A. Fasching (Peter); O. Fletcher (Olivia); H. Flyger (Henrik); F. Fostira (Florentia); Gaborieau, V. (Valerie); M. García-Closas (Montserrat); G.G. Giles (Graham); Grip, M. (Mervi); P. Guénel (Pascal); C.A. Haiman (Christopher A.); U. Hamann (Ute); J.M. Hartman (Joost); X. Miao; A. Hollestelle (Antoinette); J.L. Hopper (John); Hsiung, C.-N. (Chia-Ni); H. Ito (Hidemi); A. Jakubowska (Anna); Johnson, N. (Nichola); D. Torres (Diana); M. Kabisch (Maria); D. Kang (Daehee); S. Khan (Sofia); J.A. Knight (Julia); V-M. Kosma (Veli-Matti); Lambrechts, D. (Diether); J. Li (Jingmei); A. Lindblom (Annika); A. Lophatananon (Artitaya); J. Lubinski (Jan); A. Mannermaa (Arto); S. Manoukian (Siranoush); L. Le Marchand (Loic); S. Margolin (Sara); Marme, F. (Frederik); K. Matsuo (Keitaro); C.A. McLean (Catriona Ann); A. Meindl (Alfons); K.R. Muir (K.); S.L. Neuhausen (Susan); H. Nevanlinna (Heli); S. Nord (Silje); A.-L. Borresen-Dale (Anne-Lise); J.E. Olson (Janet); N. Orr (Nick); A.M.W. van den Ouweland (Ans); P. Peterlongo (Paolo); T.C. Putti (Thomas Choudary); Rudolph, A. (Anja); Sangrajrang, S. (Suleeporn); E.J. Sawyer (Elinor); M.K. Schmidt (Marjanka); R.K. Schmutzler (Rita); C.-Y. Shen (Chen-Yang); M.-F. Hou (Ming-Feng); M. Shrubsole (Martha); M.C. Southey (Melissa); A.J. Swerdlow (Anthony ); Hwang Teo, S. (Soo); B. Thienpont (Bernard); A.E. Toland (Amanda); R.A.E.M. Tollenaar (Rob); I.P. Tomlinson (Ian); T. Truong (Thérèse); C.-C. Tseng (Chiu-Chen); W. Wen (Wanqing); R. Winqvist (Robert); A.H. Wu (Anna); C. Har Yip (Cheng); P.M. Zamora (Pilar M.); Zheng, Y. (Ying); O.A.M. Floris; Cheng, C.-Y. (Ching-Yu); M.J. Hooning (Maartje); J.W.M. Martens (John); C.M. Seynaeve (Caroline); V. Kristensen (Vessela); P. Hall (Per); P.D.P. Pharoah (Paul); J. Simard (Jacques); G. Chenevix-Trench (Georgia); A.M. Dunning (Alison); A.C. Antoniou (Antonis C.); D.F. Easton (Douglas F.); Q. Cai (Qiuyin); J. Long (Jirong)
2016-01-01
textabstractPrevious genome-wide association studies among women of European ancestry identified two independent breast cancer susceptibility loci represented by single nucleotide polymorphisms (SNPs) rs13281615 and rs11780156 at 8q24. A fine-mapping study across 2.06 Mb
10. Multidisciplinary Treatment of the Metabolic Syndrome Lowers Blood Pressure Variability Independent of Blood Pressure Control.
Marcus, Yonit; Segev, Elad; Shefer, Gabi; Sack, Jessica; Tal, Brurya; Yaron, Marianna; Carmeli, Eli; Shefer, Lili; Margaliot, Miri; Limor, Rona; Gilad, Suzan; Sofer, Yael; Stern, Naftali
2016-01-01
Blood pressure (BP) variability (BPV) contributes to target organ damage independent of BP. The authors examined the effect of a 1-year multidisciplinary intervention on BPV in patients with the metabolic syndrome (MetS) as defined by criteria from the Third Report of the Adult Treatment Panel. Forty-four nondiabetic patients underwent clinical and biochemical profiling, 24-hour ambulatory BP monitoring (ABPM), body composition, carotid intima-media thickness, and carotid-femoral pulse wave velocity (PWV). The intervention targeted all MetS components. BPV was assessed by the standard deviation of daytime systolic BP derived from ABPM. Patients with low and high BPV (lower or higher than the median daytime standard deviation of 11.6 mm Hg) did not differ in regards to systolic and diastolic BP, age, fasting glucose, glycated hemoglobin, and body mass index, but the high-variability group had higher values of low-density lipoprotein and leg fat. The 1-year intervention resulted in weight reduction but not BP-lowering. BPV declined in the high-variability group in association with lowering of PWV, C-reactive protein, glycated hemoglobin, alanine aminotransferase, asymmetric dimethylarginine, and increased high-density lipoprotein cholesterol. A multidisciplinary intervention independent of BP-lowering normalized BPV, lowered PWV, and enhanced metabolic control. © 2015 Wiley Periodicals, Inc.
11. Relative position control and coalescence of independent microparticles using ultrasonic waves
Deng, Shuang; Jia, Kun; Chen, Jian; Mei, Deqing; Yang, Keji
2017-05-01
Controlling the relative positions and coalescence of independent cells or microparticles is of particular importance for studying many physical phenomena, biological research, pharmaceutical tests, and chemical material processing. In this work, contactless maneuvering of two independent microparticles initially lying on a rigid surface was performed at a stable levitation height within a water-filled ultrasonic chamber. Three lead zirconate titanate transducers with 2 MHz thickness resonance frequency were obliquely mounted in a homemade device to form a sound field in a half space. By modulating the excitation voltage of a single transducer and the subsequent combination of amplitude and phase modulation, two separate 80 μm diameter silica beads were picked up from the chamber bottom, approached, and then coalesced to form a cluster in different ways. Both particles simultaneously migrated towards each other in the former process, while more dexterous movement with single-particle migration was realized for the other process. There is good agreement between the measured trajectories and theoretical predictions based on the theory of the first-order acoustic radiation force. The method introduced here also has the ability to form a cluster at any desired location in the chamber, which is promising for macromolecule processing ranging from the life sciences to biochemistry and clinical practice.
12. Independent Orbiter Assessment (IOA): Assessment of the guidance, navigation, and control subsystem FMEA/CIL
Trahan, W. H.; Odonnell, R. A.; Pietz, K. C.; Drapela, L. J.
1988-01-01
The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA effort first completed an analysis of the Guidance, Navigation, and Control System (GNC) hardware, generating draft failure modes and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The IOA results were then compared to the NASA FMEA/CIL baseline with proposed Post 51-L updates included. A resolution of each discrepancy from the comparison is provided through additional analysis as required. The results of that comparison for the Orbiter GNC hardware is documented. The IOA product for the GNC analysis consisted of 141 failure mode worksheets that resulted in 24 potential critical items being identified. Comparison was made to the NASA baseline which consisted of 148 FMEAs and 36 CIL items. This comparison produced agreement on all but 56 FMEAs which caused differences in zero CIL items.
13. Independent Orbiter Assessment (IOA): Assessment of the ascent thrust vector control actuator subsystem FMEA/CIL
Wilson, R. E.
1988-01-01
The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA effort first completed an analysis of the Ascent Thrust Vector Control Actuator (ATVD) hardware, generating draft failure modes and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The IOA results were then compared to the NASA FMEA/CIL baseline with proposed Post 51-L updates included. A resolution of each discrepancy from the comparison is provided through additional analysis as required. This report documents the results of that comparison for the Orbiter ATVC hardware. The IOA product for the ATVC actuator analysis consisted of 25 failure mode worksheets that resulted in 16 potential critical items being identified. Comparison was made to the NASA baseline which consisted of 21 FMEAs and 13 CIL items. This comparison produced agreement on all CIL items. Based on the Pre 51-L baseline, all non-CIL FMEAs were also in agreement.
14. A prototype of volume-controlled tidal liquid ventilator using independent piston pumps.
Robert, Raymond; Micheau, Philippe; Cyr, Stéphane; Lesur, Olivier; Praud, Jean-Paul; Walti, Hervé
2006-01-01
Liquid ventilation using perfluorochemicals (PFC) offers clear theoretical advantages over gas ventilation, such as decreased lung damage, recruitment of collapsed lung regions, and lavage of inflammatory debris. We present a total liquid ventilator designed to ventilate patients with completely filled lungs with a tidal volume of PFC liquid. The two independent piston pumps are volume controlled and pressure limited. Measurable pumping errors are corrected by a programmed supervisor module, which modifies the inserted or withdrawn volume. Pump independence also allows easy functional residual capacity modifications during ventilation. The bubble gas exchanger is divided into two sections such that the PFC exiting the lungs is not in contact with the PFC entering the lungs. The heating system is incorporated into the metallic base of the gas exchanger, and a heat-sink-type condenser is placed on top of the exchanger to retrieve PFC vapors. The prototype was tested on 5 healthy term newborn lambs (<5 days old). The results demonstrate the efficiency and safety of the prototype in maintaining adequate gas exchange, normal acido-basis equilibrium, and cardiovascular stability during a short, 2-hour total liquid ventilator. Airway pressure, lung volume, and ventilation scheme were maintained in the targeted range.
15. Multiple cognitive control mechanisms associated with the nature of conflict.
Kim, Chobok; Chung, Chongwook; Kim, Jeounghoon
2010-06-07
Cognitive control is required to regulate conflict. The conflict monitoring theory suggests that the dorsal anterior cingulate cortex (dACC) is involved in detecting response conflict and the dorsolateral prefrontal cortex (DLPFC) plays a critical role in regulating conflict. Recent studies, however, have suggested that rostral dACC (rdACC) responds to response conflict whereas caudal dACC (cdACC) is associated with perceptual conflict. Moreover, DLPFC has been engaged only in regulation of response conflict. A neural network involved in perceptual conflict, however, remains unclear. In this study, we used functional magnetic resonance imaging (fMRI) in an attempt to reveal monitor-controller networks corresponding to either perceptual conflict or response conflict. A version of the Stroop color matching task was used to manipulate perceptual conflict, response conflict was manipulated by an arrow. The results demonstrated that rdACC and DLPFC were engaged in response conflict whereas cdACC and the dorsal portion of premotor cortex (pre-PMd) were involved in perceptual conflict. Interestingly, the posterior parietal cortex (PPC) was activated by both types of conflict. Correlation analyses between behavioral conflict effects and neural responses demonstrated that rdACC and DLPFC were associated with response conflict whereas cdACC and pre-PMd were associated with perceptual conflict. PPC was not correlated with either perceptual conflict or response conflict. We suggest that cdACC and pre-PMd play critical roles in perceptual conflict processing, and this network is independent from the rdACC/DLPFC network for response conflict processing. We also discussed the function of PPC in conflict processing. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.
16. NEMA NU-1 2007 based and independent quality control software for gamma cameras and SPECT
Vickery, A; Joergensen, T; De Nijs, R
2011-01-01
A thorough quality assurance of gamma and SPECT cameras requires a careful handling of the measured quality control (QC) data. Most gamma camera manufacturers provide the users with camera specific QC Software. This QC software is indeed a useful tool for the following of day-to-day performance of a single camera. However, when it comes to objective performance comparison of different gamma cameras and a deeper understanding of the calculated numbers, the use of camera specific QC software without access to the source code is rather avoided. Calculations and definitions might differ, and manufacturer independent standardized results are preferred. Based upon the NEMA Standards Publication NU 1-2007, we have developed a suite of easy-to-use data handling software for processing acquired QC data providing the user with instructive images and text files with the results.
17. Independent control of the vortex chirality and polarity in a pair of magnetic nanodots
Li, Junqin; Wang, Yong, E-mail: wangyong@sinap.ac.cn; Cao, Jiefeng; Meng, Xiangyu; Zhu, Fangyuan; Wu, Yanqing; Tai, Renzhong
2017-08-01
Independent control of the vortex chirality and polarity is realized by changing the in-plane magnetic field direction in nanodot pair through Object Oriented Micromagnetic Framework (OOMMF) simulation. The two magnetic circles are close to each other and have magnetic interaction. The two circles always have the same polarity and opposite chirality at every remanent state. There are totally four predictable magnetic states in the nanodot pair which can be obtained in the remanent state relaxed from the saturation state along all possible directions. An explanation on the formation of vortex states is given by vortex dynamics. The vortex states are stable in large out-of-plane magnetic field which is in a direction opposite to the vortex polarity. The geometry of the nanodot pair gives a way to easily realize a vortex state with specific polarity and chirality.
18. A Nodal-independent and tissue-intrinsic mechanism controls heart-looping chirality
Noël, Emily S.; Verhoeven, Manon; Lagendijk, Anne Karine; Tessadori, Federico; Smith, Kelly; Choorapoikayil, Suma; den Hertog, Jeroen; Bakkers, Jeroen
2013-11-01
Breaking left-right symmetry in bilateria is a major event during embryo development that is required for asymmetric organ position, directional organ looping and lateralized organ function in the adult. Asymmetric expression of Nodal-related genes is hypothesized to be the driving force behind regulation of organ laterality. Here we identify a Nodal-independent mechanism that drives asymmetric heart looping in zebrafish embryos. In a unique mutant defective for the Nodal-related southpaw gene, preferential dextral looping in the heart is maintained, whereas gut and brain asymmetries are randomized. As genetic and pharmacological inhibition of Nodal signalling does not abolish heart asymmetry, a yet undiscovered mechanism controls heart chirality. This mechanism is tissue intrinsic, as explanted hearts maintain ex vivo retain chiral looping behaviour and require actin polymerization and myosin II activity. We find that Nodal signalling regulates actin gene expression, supporting a model in which Nodal signalling amplifies this tissue-intrinsic mechanism of heart looping.
19. MISO Current-mode Biquad Filter with Independent Control of Pole Frequency and Quality Factor
W. Jaikla
2012-09-01
Full Text Available This article presents a three-inputs single-output biquadratic filter performing completely standard functions: low-pass, high-pass, band-pass, band-reject and all-pass functions, based on current controlled current conveyor transconductance amplifier (CCCCTA. The quality factor and pole frequency can be electronically/independently tuned via the input bias current. The proposed circuit uses 2 CCCCTAs and 2 grounded capacitors without external any resistors which is very suitable to further develop into an integrated circuit. The filter does not require double input current signal. Each function response can be selected by suitably selecting input signals with digital method. Moreover, the circuit possesses high output impedance which would be an ideal choice for current-mode cascading. The PSPICE simulation results are included to verify the workability of the proposed filter. The given results agree well with the theoretical anticipation.
20. Plasma oxytocin concentrations are lower in depressed vs. healthy control women and are independent of cortisol.
Yuen, Kaeli W; Garner, Joseph P; Carson, Dean S; Keller, Jennifer; Lembke, Anna; Hyde, Shellie A; Kenna, Heather A; Tennakoon, Lakshika; Schatzberg, Alan F; Parker, Karen J
2014-04-01
The neuropeptide oxytocin (OT) promotes social behavior and attenuates stress responsivity in mammals. Recent clinical evidence suggests OT concentrations may be dysregulated in major depression. This study extends previous research by testing whether: 1) OT concentrations vary systematically in depressive disorders with and without hypercortisolemia, 2) gender differences in OT concentrations are observed in depressed vs. healthy control participants, and 3) OT concentrations are predictive of clinical phenotypes. Plasma OT concentrations of psychotic major depressive (PMD; n = 14: 10 female, 4 male), non-psychotic major depressive (NPMD; n = 17: 12 female, 5 male), and non-depressed, healthy control (n = 19: 11 female, 8 male) participants were assayed at 2000, 2400, 0400, and 0800 h. Plasma cortisol concentrations were quantified at 2300 h, and clinical phenotypes were determined. As expected, PMD participants, compared to NPMD and healthy control participants, showed higher plasma cortisol concentrations. Although both depressed groups showed similar OT concentrations, a significant interaction effect between group and gender was observed. Specifically, depressed females exhibited lower mean OT concentrations than depressed males. Further, depressed vs. healthy control female participants exhibited lower mean OT concentrations, whereas depressed vs. healthy control male participants showed a trend in the opposite direction. OT concentrations were also predictive of desirability, drug dependence, and compulsivity scores as measured by the Million Clinical Multiaxial Inventory-III. All findings were independent of cortisol. These data suggest that OT signaling may provide a mechanism by which to better understand female-biased risk to develop depressive disorders and that plasma OT concentrations may be a useful biomarker of certain clinical phenotypes. Copyright © 2013. Published by Elsevier Ltd.
1. An Inverse Optimal Control Approach to Explain Human Arm Reaching Control Based on Multiple Internal Models.
Oguz, Ozgur S; Zhou, Zhehua; Glasauer, Stefan; Wollherr, Dirk
2018-04-03
Human motor control is highly efficient in generating accurate and appropriate motor behavior for a multitude of tasks. This paper examines how kinematic and dynamic properties of the musculoskeletal system are controlled to achieve such efficiency. Even though recent studies have shown that the human motor control relies on multiple models, how the central nervous system (CNS) controls this combination is not fully addressed. In this study, we utilize an Inverse Optimal Control (IOC) framework in order to find the combination of those internal models and how this combination changes for different reaching tasks. We conducted an experiment where participants executed a comprehensive set of free-space reaching motions. The results show that there is a trade-off between kinematics and dynamics based controllers depending on the reaching task. In addition, this trade-off depends on the initial and final arm configurations, which in turn affect the musculoskeletal load to be controlled. Given this insight, we further provide a discomfort metric to demonstrate its influence on the contribution of different inverse internal models. This formulation together with our analysis not only support the multiple internal models (MIMs) hypothesis but also suggest a hierarchical framework for the control of human reaching motions by the CNS.
2. Sliding-mode control of single input multiple output DC-DC converter
Zhang, Libo; Sun, Yihan; Luo, Tiejian; Wan, Qiyang
2016-10-01
Various voltage levels are required in the vehicle mounted power system. A conventional solution is to utilize an independent multiple output DC-DC converter whose cost is high and control scheme is complicated. In this paper, we design a novel SIMO DC-DC converter with sliding mode controller. The proposed converter can boost the voltage of a low-voltage input power source to a controllable high-voltage DC bus and middle-voltage output terminals, which endow the converter with characteristics of simple structure, low cost, and convenient control. In addition, the sliding mode control (SMC) technique applied in our converter can enhance the performances of a certain SIMO DC-DC converter topology. The high-voltage DC bus can be regarded as the main power source to the high-voltage facility of the vehicle mounted power system, and the middle-voltage output terminals can supply power to the low-voltage equipment on an automobile. In the respect of control algorithm, it is the first time to propose the SMC-PID (Proportion Integration Differentiation) control algorithm, in which the SMC algorithm is utilized and the PID control is attended to the conventional SMC algorithm. The PID control increases the dynamic ability of the SMC algorithm by establishing the corresponding SMC surface and introducing the attached integral of voltage error, which endow the sliding-control system with excellent dynamic performance. At last, we established the MATLAB/SIMULINK simulation model, tested performance of the system, and built the hardware prototype based on Digital Signal Processor (DSP). Results show that the sliding mode control is able to track a required trajectory, which has robustness against the uncertainties and disturbances.
3. Multiple independent variants at the TERT locus are associated with telomere length and risks of breast and ovarian cancer
Bojesen, Stig E.; Pooley, Karen A.; Johnatty, Sharon E.; Beesley, Jonathan; Michailidou, Kyriaki; Tyrer, Jonathan P.; Edwards, Stacey L.; Pickett, Hilda A.; Shen, Howard C.; Smart, Chanel E.; Hillman, Kristine M.; Mai, Phuong L.; Lawrenson, Kate; Stutz, Michael D.; Lu, Yi; Karevan, Rod; Woods, Nicholas; Johnston, Rebecca L.; French, Juliet D.; Chen, Xiaoqing; Weischer, Maren; Nielsen, Sune F.; Maranian, Melanie J.; Ghoussaini, Maya; Ahmed, Shahana; Baynes, Caroline; Bolla, Manjeet K.; Wang, Qin; Dennis, Joe; McGuffog, Lesley; Barrowdale, Daniel; Lee, Andrew; Healey, Sue; Lush, Michael; Tessier, Daniel C.; Vincent, Daniel; Bacot, Françis; Vergote, Ignace; Lambrechts, Sandrina; Despierre, Evelyn; Risch, Harvey A.; González-Neira, Anna; Rossing, Mary Anne; Pita, Guillermo; Doherty, Jennifer A.; Alvarez, Nuria; Larson, Melissa C.; Fridley, Brooke L.; Schoof, Nils; Chang-Claude, Jenny; Cicek, Mine S.; Peto, Julian; Kalli, Kimberly R.; Broeks, Annegien; Armasu, Sebastian M.; Schmidt, Marjanka K.; Braaf, Linde M.; Winterhoff, Boris; Nevanlinna, Heli; Konecny, Gottfried E.; Lambrechts, Diether; Rogmann, Lisa; Guénel, Pascal; Teoman, Attila; Milne, Roger L.; Garcia, Joaquin J.; Cox, Angela; Shridhar, Vijayalakshmi; Burwinkel, Barbara; Marme, Frederik; Hein, Rebecca; Sawyer, Elinor J.; Haiman, Christopher A.; Wang-Gohrke, Shan; Andrulis, Irene L.; Moysich, Kirsten B.; Hopper, John L.; Odunsi, Kunle; Lindblom, Annika; Giles, Graham G.; Brenner, Hermann; Simard, Jacques; Lurie, Galina; Fasching, Peter A.; Carney, Michael E.; Radice, Paolo; Wilkens, Lynne R.; Swerdlow, Anthony; Goodman, Marc T.; Brauch, Hiltrud; Garcia-Closas, Montserrat; Hillemanns, Peter; Winqvist, Robert; Dürst, Matthias; Devilee, Peter; Runnebaum, Ingo; Jakubowska, Anna; Lubinski, Jan; Mannermaa, Arto; Butzow, Ralf; Bogdanova, Natalia V.; Dörk, Thilo; Pelttari, Liisa M.; Zheng, Wei; Leminen, Arto; Anton-Culver, Hoda; Bunker, Clareann H.; Kristensen, Vessela; Ness, Roberta B.; Muir, Kenneth; Edwards, Robert; Meindl, Alfons; Heitz, Florian; Matsuo, Keitaro; du Bois, Andreas; Wu, Anna H.; Harter, Philipp; teo, Soo-Hwang; Schwaab, Ira; Shu, Xiao-Ou; Blot, William; Hosono, Satoyo; Kang, Daehee; Nakanishi, Toru; Hartman, Mikael; Yatabe, Yasushi; Hamann, Ute; Karlan, Beth Y.; Sangrajrang, Suleeporn; Kjaer, Susanne Krüger; Gaborieau, Valerie; Jensen, Allan; Eccles, Diana; Høgdall, Estrid; Shen, Chen-Yang; Brown, Judith; Woo, Yin Ling; Shah, Mitul; Azmi, Mat Adenan Noor; Luben, Robert; Omar, Siti Zawiah; Czene, Kamila; Vierkant, Robert A.; Nordestgaard, Børge G.; Flyger, Henrik; Vachon, Celine; Olson, Janet E.; Wang, Xianshu; Levine, Douglas A.; Rudolph, Anja; Weber, Rachel Palmieri; Flesch-Janys, Dieter; Iversen, Edwin; Nickels, Stefan; Schildkraut, Joellen M.; Silva, Isabel Dos Santos; Cramer, Daniel W.; Gibson, Lorna; Terry, Kathryn L.; Fletcher, Olivia; Vitonis, Allison F.; van der Schoot, C. Ellen; Poole, Elizabeth M.; Hogervorst, Frans B. L.; Tworoger, Shelley S.; Liu, Jianjun; Bandera, Elisa V.; Li, Jingmei; Olson, Sara H.; Humphreys, Keith; Orlow, Irene; Blomqvist, Carl; Rodriguez-Rodriguez, Lorna; Aittomäki, Kristiina; Salvesen, Helga B.; Muranen, Taru A.; Wik, Elisabeth; Brouwers, Barbara; Krakstad, Camilla; Wauters, Els; Halle, Mari K.; Wildiers, Hans; Kiemeney, Lambertus A.; Mulot, Claire; Aben, Katja K.; Laurent-Puig, Pierre; Altena, Anne Mvan; Truong, Thérèse; Massuger, Leon F. A. G.; Benitez, Javier; Pejovic, Tanja; Perez, Jose Ignacio Arias; Hoatlin, Maureen; Zamora, M. Pilar; Cook, Linda S.; Balasubramanian, Sabapathy P.; Kelemen, Linda E.; Schneeweiss, Andreas; Le, Nhu D.; Sohn, Christof; Brooks-Wilson, Angela; Tomlinson, Ian; Kerin, Michael J.; Miller, Nicola; Cybulski, Cezary; Henderson, Brian E.; Menkiszak, Janusz; Schumacher, Fredrick; Wentzensen, Nicolas; Le Marchand, Loic; Yang, Hannah P.; Mulligan, Anna Marie; Glendon, Gord; Engelholm, Svend Aage; Knight, Julia A.; Høgdall, Claus K.; Apicella, Carmel; Gore, Martin; Tsimiklis, Helen; Song, Honglin; Southey, Melissa C.; Jager, Agnes; den Ouweland, Ans M. Wvan; Brown, Robert; Martens, John W. M.; Flanagan, James M.; Kriege, Mieke; Paul, James; Margolin, Sara; Siddiqui, Nadeem; Severi, Gianluca; Whittemore, Alice S.; Baglietto, Laura; McGuire, Valerie; Stegmaier, Christa; Sieh, Weiva; Müller, Heiko; Arndt, Volker; Labrèche, France; Gao, Yu-Tang; Goldberg, Mark S.; Yang, Gong; Dumont, Martine; McLaughlin, John R.; Hartmann, Arndt; Ekici, Arif B.; Beckmann, Matthias W.; Phelan, Catherine M.; Lux, Michael P.; Permuth-Wey, Jenny; Peissel, Bernard; Sellers, Thomas A.; Ficarazzi, Filomena; Barile, Monica; Ziogas, Argyrios; Ashworth, Alan; Gentry-Maharaj, Aleksandra; Jones, Michael; Ramus, Susan J.; Orr, Nick; Menon, Usha; Pearce, Celeste L.; Brüning, Thomas; Pike, Malcolm C.; Ko, Yon-Dschun; Lissowska, Jolanta; Figueroa, Jonine; Kupryjanczyk, Jolanta; Chanock, Stephen J.; Dansonka-Mieszkowska, Agnieszka; Jukkola-Vuorinen, Arja; Rzepecka, Iwona K.; Pylkäs, Katri; Bidzinski, Mariusz; Kauppila, Saila; Hollestelle, Antoinette; Seynaeve, Caroline; Tollenaar, Rob A. E. M.; Durda, Katarzyna; Jaworska, Katarzyna; Hartikainen, Jaana M.; Kosma, Veli-Matti; Kataja, Vesa; Antonenkova, Natalia N.; Long, Jirong; Shrubsole, Martha; Deming-Halverson, Sandra; Lophatananon, Artitaya; Siriwanarangsan, Pornthep; Stewart-Brown, Sarah; Ditsch, Nina; Lichtner, Peter; Schmutzler, Rita K.; Ito, Hidemi; Iwata, Hiroji; Tajima, Kazuo; Tseng, Chiu-Chen; Stram, Daniel O.; van den Berg, David; Yip, Cheng Har; Ikram, M. Kamran; teh, Yew-Ching; Cai, Hui; Lu, Wei; Signorello, Lisa B.; Cai, Qiuyin; Noh, Dong-Young; Yoo, Keun-Young; Miao, Hui; Iau, Philip Tsau-Choong; teo, Yik Ying; McKay, James; Shapiro, Charles; Ademuyiwa, Foluso; Fountzilas, George; Hsiung, Chia-Ni; Yu, Jyh-Cherng; Hou, Ming-Feng; Healey, Catherine S.; Luccarini, Craig; Peock, Susan; Stoppa-Lyonnet, Dominique; Peterlongo, Paolo; Rebbeck, Timothy R.; Piedmonte, Marion; Singer, Christian F.; Friedman, Eitan; Thomassen, Mads; Offit, Kenneth; Hansen, Thomas V. O.; Neuhausen, Susan L.; Szabo, Csilla I.; Blanco, Ignacio; Garber, Judy; Narod, Steven A.; Weitzel, Jeffrey N.; Montagna, Marco; Olah, Edith; Godwin, Andrew K.; Yannoukakos, Drakoulis; Goldgar, David E.; Caldes, Trinidad; Imyanitov, Evgeny N.; Tihomirova, Laima; Arun, Banu K.; Campbell, Ian; Mensenkamp, Arjen R.; van Asperen, Christi J.; van Roozendaal, Kees E. P.; Meijers-Heijboer, Hanne; Collée, J. Margriet; Oosterwijk, Jan C.; Hooning, Maartje J.; Rookus, Matti A.; van der Luijt, Rob B.; Os, Theo A. Mvan; Evans, D. Gareth; Frost, Debra; Fineberg, Elena; Barwell, Julian; Walker, Lisa; Kennedy, M. John; Platte, Radka; Davidson, Rosemarie; Ellis, Steve D.; Cole, Trevor; Bressac-de Paillerets, Brigitte; Buecher, Bruno; Damiola, Francesca; Faivre, Laurence; Frenay, Marc; Sinilnikova, Olga M.; Caron, Olivier; Giraud, Sophie; Mazoyer, Sylvie; Bonadona, Valérie; Caux-Moncoutier, Virginie; Toloczko-Grabarek, Aleksandra; Gronwald, Jacek; Byrski, Tomasz; Spurdle, Amanda B.; Bonanni, Bernardo; Zaffaroni, Daniela; Giannini, Giuseppe; Bernard, Loris; Dolcetti, Riccardo; Manoukian, Siranoush; Arnold, Norbert; Engel, Christoph; Deissler, Helmut; Rhiem, Kerstin; Niederacher, Dieter; Plendl, Hansjoerg; Sutter, Christian; Wappenschmidt, Barbara; Borg, Ake; Melin, Beatrice; Rantala, Johanna; Soller, Maria; Nathanson, Katherine L.; Domchek, Susan M.; Rodriguez, Gustavo C.; Salani, Ritu; Kaulich, Daphne Gschwantler; tea, Muy-Kheng; Paluch, Shani Shimon; Laitman, Yael; Skytte, Anne-Bine; Kruse, Torben A.; Jensen, Uffe Birk; Robson, Mark; Gerdes, Anne-Marie; Ejlertsen, Bent; Foretova, Lenka; Savage, Sharon A.; Lester, Jenny; Soucy, Penny; Kuchenbaecker, Karoline B.; Olswold, Curtis; Cunningham, Julie M.; Slager, Susan; Pankratz, Vernon S.; Dicks, Ed; Lakhani, Sunil R.; Couch, Fergus J.; Hall, Per; Monteiro, Alvaro N. A.; Gayther, Simon A.; Pharoah, Paul D. P.; Reddel, Roger R.; Goode, Ellen L.; Greene, Mark H.; Easton, Douglas F.; Berchuck, Andrew; Antoniou, Antonis C.; Chenevix-Trench, Georgia; Dunning, Alison M.
2013-01-01
TERT-locus SNPs and leukocyte telomere measures are reportedly associated with risks of multiple cancers. Using the Illumina custom genotyping array iCOGs, we analyzed ∼480 SNPs at the TERT locus in breast (n = 103,991), ovarian (n = 39,774) and BRCA1 mutation carrier (n = 11,705) cancer cases and
4. Multiple independent variants at the TERT locus are associated with telomere length and risks of breast and ovarian cancer
Bojesen, Stig Egil; Pooley, Karen A; Johnatty, Sharon E
2013-01-01
TERT-locus SNPs and leukocyte telomere measures are reportedly associated with risks of multiple cancers. Using the Illumina custom genotyping array iCOGs, we analyzed ∼480 SNPs at the TERT locus in breast (n = 103,991), ovarian (n = 39,774) and BRCA1 mutation carrier (n = 11,705) cancer cases...
5. Hybrid Control System for Greater Resilience Using Multiple Isolation and Building Connection
Masaki Taniguchi
2016-10-01
Full Text Available An innovative hybrid control building system of multiple isolation and connection is proposed and investigated using both time-history and input energy responses for various types of ground motions together with transfer functions. It is concerned that the seismic displacement response at the base-isolation layer of the existing base-isolated buildings may extremely increase under long-period and long-duration ground motions which are getting great attention recently. In order to enhance the seismic performance of those base-isolated buildings, a novel hybrid system of multiple isolation and building-connection is proposed and compared with other structural systems such as an independent multiple isolation system, a hybrid system of base-isolation and building-connection. Furthermore, the robustness of seismic responses of the proposed hybrid system for various types of ground motion is discussed through the comparison of various structural systems including non-hybrid systems. Finally the optimal connection damper location is investigated using a sensitivity-type optimization approach.
6. Development of a platform-independent receiver control system for SISIFOS
Lemke, Roland; Olberg, Michael
1998-05-01
Up to now receiver control software was a time consuming development usually written by receiver engineers who had mainly the hardware in mind. We are presenting a low-cost and very flexible system which uses a minimal interface to the real hardware, and which makes it easy to adapt to new receivers. Our system uses Tcl/Tk as a graphical user interface (GUI), SpecTcl as a GUI builder, Pgplot as plotting software, a simple query language (SQL) database for information storage and retrieval, Ethernet socket to socket communication and SCPI as a command control language. The complete system is in principal platform independent but for cost saving reasons we are using it actually on a PC486 running Linux 2.0.30, which is a copylefted Unix. The only hardware dependent part are the digital input/output boards, analog to digital and digital to analog convertors. In the case of the Linux PC we are using a device driver development kit to integrate the boards fully into the kernel of the operating system, which indeed makes them look like an ordinary device. The advantage of this system is firstly the low price and secondly the clear separation between the different software components which are available for many operating systems. If it is not possible, due to CPU performance limitations, to run all the software in a single machine,the SQL-database or the graphical user interface could be installed on separate computers.
7. Androgen receptor-dependent and -independent mechanisms driving prostate cancer progression: Opportunities for therapeutic targeting from multiple angles
Hoang, David T; Iczkowski, Kenneth A; Kilari, Deepak; See, William; Nevalainen, Marja T
2017-01-01
Despite aggressive treatment for localized cancer, prostate cancer (PC) remains a leading cause of cancer-related death for American men due to a subset of patients progressing to lethal and incurable metastatic castrate-resistant prostate cancer (CRPC). Organ-confined PC is treated by surgery or radiation with or without androgen deprivation therapy (ADT), while options for locally advanced and disseminated PC include radiation combined with ADT, or systemic treatments including chemotherapy. Progression to CRPC results from failure of ADT, which targets the androgen receptor (AR) signaling axis and inhibits AR-driven proliferation and survival pathways. The exact mechanisms underlying the transition from androgen-dependent PC to CRPC remain incompletely understood. Reactivation of AR has been shown to occur in CRPC despite depletion of circulating androgens by ADT. At the same time, the presence of AR-negative cell populations in CRPC has also been identified. While AR signaling has been proposed as the primary driver of CRPC, AR-independent signaling pathways may represent additional mechanisms underlying CRPC progression. Identification of new therapeutic strategies to target both AR-positive and AR-negative PC cell populations and, thereby, AR-driven as well as non-AR-driven PC cell growth and survival mechanisms would provide a two-pronged approach to eliminate CRPC cells with potential for synthetic lethality. In this review, we provide an overview of AR-dependent and AR-independent molecular mechanisms which drive CRPC, with special emphasis on the role of the Jak2-Stat5a/b signaling pathway in promoting castrate-resistant growth of PC through both AR-dependent and AR-independent mechanisms. PMID:27741508
8. A Spanish pillbox app for elderly patients taking multiple medications: randomized controlled trial.
Mira, José Joaquín; Navarro, Isabel; Botella, Federico; Borrás, Fernando; Nuño-Solinís, Roberto; Orozco, Domingo; Iglesias-Alonso, Fuencisla; Pérez-Pérez, Pastora; Lorenzo, Susana; Toro, Nuria
2014-04-04
Nonadherence and medication errors are common among patients with complex drug regimens. Apps for smartphones and tablets are effective for improving adherence, but they have not been tested in elderly patients with complex chronic conditions and who typically have less experience with this type of technology. The objective of this study was to design, implement, and evaluate a medication self-management app (called ALICE) for elderly patients taking multiple medications with the intention of improving adherence and safe medication use. A single-blind randomized controlled trial was conducted with a control and an experimental group (N=99) in Spain in 2013. The characteristics of ALICE were specified based on the suggestions of 3 nominal groups with a total of 23 patients and a focus group with 7 professionals. ALICE was designed for Android and iOS to allow for the personalization of prescriptions and medical advice, showing images of each of the medications (the packaging and the medication itself) together with alerts and multiple reminders for each alert. The randomly assigned patients in the control group received oral and written information on the safe use of their medications and the patients in the experimental group used ALICE for 3 months. Pre and post measures included rate of missed doses and medication errors reported by patients, scores from the 4-item Morisky Medication Adherence Scale (MMAS-4), level of independence, self-perceived health status, and biochemical test results. In the experimental group, data were collected on their previous experience with information and communication technologies, their rating of ALICE, and their perception of the level of independence they had achieved. The intergroup intervention effects were calculated by univariate linear models and ANOVA, with the pre to post intervention differences as the dependent variables. Data were obtained from 99 patients (48 and 51 in the control and experimental groups, respectively
9. The Impact of Multiple Concussions on Emotional Distress, Post-Concussive Symptoms, and Neurocognitive Functioning in Active Duty United States Marines Independent of Combat Exposure or Emotional Distress
Lathan, Corinna E.; Bleiberg, Joseph; Tsao, Jack W.
2014-01-01
Abstract Controversy exists as to whether the lingering effects of concussion on emotional, physical, and cognitive symptoms is because of the effects of brain trauma or purely to emotional factors such as post-traumatic stress disorder or depression. This study examines the independent effects of concussion on persistent symptoms. The Defense Automated Neurobehavioral Assessment, a clinical decision support tool, was used to assess neurobehavioral functioning in 646 United States Marines, all of whom were fit for duty. Marines were assessed for concussion history, post-concussive symptoms, emotional distress, neurocognitive functioning, and deployment history. Results showed that a recent concussion or ever having experienced a concussion was associated with an increase in emotional distress, but not with persistent post-concussive symptoms (PPCS) or neurocognitive functioning. Having had multiple lifetime concussions, however, was associated with greater emotional distress, PPCS, and reduced neurocognitive functioning that needs attention and rapid discrimination, but not for memory-based tasks. These results are independent of deployment history, combat exposure, and symptoms of post-traumatic stress disorder and depression. Results supported earlier findings that a previous concussion is not generally associated with post-concussive symptoms independent of covariates. In contrast with other studies that failed to find a unique contribution for concussion to PPCS, however, evidence of recent and multiple concussion was seen across a range of emotional distress, post-concussive symptoms, and neurocognitive functioning in this study population. Results are discussed in terms of implications for assessing concussion on return from combat. PMID:25003552
10. Stratifying empiric risk of schizophrenia among first degree relatives using multiple predictors in two independent Indian samples.
Bhatia, Triptish; Gettig, Elizabeth A; Gottesman, Irving I; Berliner, Jonathan; Mishra, N N; Nimgaonkar, Vishwajit L; Deshpande, Smita N
2016-12-01
Schizophrenia (SZ) has an estimated heritability of 64-88%, with the higher values based on twin studies. Conventionally, family history of psychosis is the best individual-level predictor of risk, but reliable risk estimates are unavailable for Indian populations. Genetic, environmental, and epigenetic factors are equally important and should be considered when predicting risk in 'at risk' individuals. To estimate risk based on an Indian schizophrenia participant's family history combined with selected demographic factors. To incorporate variables in addition to family history, and to stratify risk, we constructed a regression equation that included demographic variables in addition to family history. The equation was tested in two independent Indian samples: (i) an initial sample of SZ participants (N=128) with one sibling or offspring; (ii) a second, independent sample consisting of multiply affected families (N=138 families, with two or more sibs/offspring affected with SZ). The overall estimated risk was 4.31±0.27 (mean±standard deviation). There were 19 (14.8%) individuals in the high risk group, 75 (58.6%) in the moderate risk and 34 (26.6%) in the above average risk (in Sample A). In the validation sample, risks were distributed as: high (45%), moderate (38%) and above average (17%). Consistent risk estimates were obtained from both samples using the regression equation. Familial risk can be combined with demographic factors to estimate risk for SZ in India. If replicated, the proposed stratification of risk may be easier and more realistic for family members. Copyright © 2016. Published by Elsevier B.V.
11. Noise promotes independent control of gamma oscillations and grid firing within recurrent attractor networks
Solanka, Lukas; van Rossum, Mark CW; Nolan, Matthew F
2015-01-01
Neural computations underlying cognitive functions require calibration of the strength of excitatory and inhibitory synaptic connections and are associated with modulation of gamma frequency oscillations in network activity. However, principles relating gamma oscillations, synaptic strength and circuit computations are unclear. We address this in attractor network models that account for grid firing and theta-nested gamma oscillations in the medial entorhinal cortex. We show that moderate intrinsic noise massively increases the range of synaptic strengths supporting gamma oscillations and grid computation. With moderate noise, variation in excitatory or inhibitory synaptic strength tunes the amplitude and frequency of gamma activity without disrupting grid firing. This beneficial role for noise results from disruption of epileptic-like network states. Thus, moderate noise promotes independent control of multiplexed firing rate- and gamma-based computational mechanisms. Our results have implications for tuning of normal circuit function and for disorders associated with changes in gamma oscillations and synaptic strength. DOI: http://dx.doi.org/10.7554/eLife.06444.001 PMID:26146940
12. Trehalose-6-phosphate synthesis controls yeast gluconeogenesis downstream and independent of SNF1.
Deroover, Sofie; Ghillebert, Ruben; Broeckx, Tom; Winderickx, Joris; Rolland, Filip
2016-06-01
Trehalose-6-P (T6P), an intermediate of trehalose biosynthesis, was identified as an important regulator of yeast sugar metabolism and signaling. tps1Δ mutants, deficient in T6P synthesis (TPS), are unable to grow on rapidly fermentable medium with uncontrolled influx in glycolysis, depletion of ATP and accumulation of sugar phosphates. However, the exact molecular mechanisms involved are not fully understood. We show that SNF1 deletion restores the tps1Δ growth defect on glucose, suggesting that lack of TPS hampers inactivation of SNF1 or SNF1-regulated processes. In addition to alternative, non-fermentable carbon metabolism, SNF1 controls two major processes: respiration and gluconeogenesis. The tps1Δ defect appears to be specifically associated with deficient inhibition of gluconeogenesis, indicating more downstream effects. Consistently, Snf1 dephosphorylation and inactivation on glucose medium are not affected, as confirmed with an in vivo Snf1 activity reporter. Detailed analysis shows that gluconeogenic Pck1 and Fbp1 expression, protein levels and activity are not repressed upon glucose addition to tps1Δ cells, suggesting a link between the metabolic defect and persistent gluconeogenesis. While SNF1 is essential for induction of gluconeogenesis, T6P/TPS is required for inactivation of gluconeogenesis in the presence of glucose, downstream and independent of SNF1 activity and the Cat8 and Sip4 transcription factors. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
13. Human brain expansion during evolution is independent of fire control and cooking
Alianda Maira Cornélio
2016-04-01
Full Text Available What makes humans unique? This question has fascinated scientists and philosophers for centuries and it is still a matter of intense debate. Nowadays, human brain expansion during evolution has been acknowledged to explain our empowered cognitive capabilities. The drivers for such accelerated expansion remain, however, largely unknown. In this sense, studies have suggested that the cooking of food could be a pre-requisite for the expansion of brain size in early hominins. However, this appealing hypothesis is only supported by a mathematical model suggesting that the increasing number of neurons in the brain would constrain body size among primates due to a limited amount of calories obtained from diets. Here, we show, by using a similar mathematical model, that a tradeoff between body mass and the number of brain neurons imposed by dietary constraints during hominin evolution is unlikely. Instead, the predictable number of neurons in the hominin brain varies much more in function of foraging efficiency than body mass. We also review archeological data to show that the expansion of the brain volume in the hominin lineage is described by a linear function independent of evidences of fire control, and therefore, thermal processing of food does not account for this phenomenon. Finally, we report experiments in mice showing that thermal processing of meat does not increase its caloric availability in mice. Altogether, our data indicate that cooking is neither sufficient nor necessary to explain hominin brain expansion.
14. Human Brain Expansion during Evolution Is Independent of Fire Control and Cooking.
Cornélio, Alianda M; de Bittencourt-Navarrete, Ruben E; de Bittencourt Brum, Ricardo; Queiroz, Claudio M; Costa, Marcos R
2016-01-01
What makes humans unique? This question has fascinated scientists and philosophers for centuries and it is still a matter of intense debate. Nowadays, human brain expansion during evolution has been acknowledged to explain our empowered cognitive capabilities. The drivers for such accelerated expansion remain, however, largely unknown. In this sense, studies have suggested that the cooking of food could be a pre-requisite for the expansion of brain size in early hominins. However, this appealing hypothesis is only supported by a mathematical model suggesting that the increasing number of neurons in the brain would constrain body size among primates due to a limited amount of calories obtained from diets. Here, we show, by using a similar mathematical model, that a tradeoff between body mass and the number of brain neurons imposed by dietary constraints during hominin evolution is unlikely. Instead, the predictable number of neurons in the hominin brain varies much more in function of foraging efficiency than body mass. We also review archeological data to show that the expansion of the brain volume in the hominin lineage is described by a linear function independent of evidence of fire control, and therefore, thermal processing of food does not account for this phenomenon. Finally, we report experiments in mice showing that thermal processing of meat does not increase its caloric availability in mice. Altogether, our data indicate that cooking is neither sufficient nor necessary to explain hominin brain expansion.
15. Cdk2 is required for p53-independent G2/M checkpoint control.
Jon H Chung
2010-02-01
Full Text Available The activation of phase-specific cyclin-dependent kinases (Cdks is associated with ordered cell cycle transitions. Among the mammalian Cdks, only Cdk1 is essential for somatic cell proliferation. Cdk1 can apparently substitute for Cdk2, Cdk4, and Cdk6, which are individually dispensable in mice. It is unclear if all functions of non-essential Cdks are fully redundant with Cdk1. Using a genetic approach, we show that Cdk2, the S-phase Cdk, uniquely controls the G(2/M checkpoint that prevents cells with damaged DNA from initiating mitosis. CDK2-nullizygous human cells exposed to ionizing radiation failed to exclude Cdk1 from the nucleus and exhibited a marked defect in G(2/M arrest that was unmasked by the disruption of P53. The DNA replication licensing protein Cdc6, which is normally stabilized by Cdk2, was physically associated with the checkpoint regulator ATR and was required for efficient ATR-Chk1-Cdc25A signaling. These findings demonstrate that Cdk2 maintains a balance of S-phase regulatory proteins and thereby coordinates subsequent p53-independent G(2/M checkpoint activation.
16. Multiband Planar Inverted-F Antenna with Independent Operating Bands Control for Mobile Handset Applications
Mustapha El Halaoui
2017-01-01
Full Text Available A new compact multiband PIFA (Planar Inverted-F Antenna for mobile handset is proposed in this article. The proposed PIFA has a simple geometry with four slots integrated in the radiating patch and ground plane. The PIFA occupies a small volume of 51 × 14 × 7.2 mm3 and is placed on the top portion of mobile phone. The optimized PIFA is worked in the 790 MHz band (737–831 MHz, the 1870 MHz band (1794–1977 MHz, the 2550 MHz band (2507–2615 MHz, and the 3400 MHz band (3341–3545 MHz, to cover LTE700, LTE800, DCS1800, PCS1900, LTE1800, LTE1900, LTE2500, and WIMAX3400 bands. Each of the four operating bands can be controlled independently by the variation of a single parameter of the proposed design, with a wide control range. An omnidirectional radiation pattern to each resonant frequency is obtained with a maximum gain of 2.15 dBi at 790 MHz, 3.99 dBi at 1870 MHz, 4.57 dBi at 2550 MHz, and 6.43 dBi at 3400 MHz. The proposed PIFA is studied in the free space and in the presence of other mobile phone components such as the battery, LCD (liquid crystal display, camera, microphone, speaker, buttons, and a plastic housing. The distribution of specific absorption rate for both European and American standards for each operating band and at various distances between the antenna and the human head is also studied.
17. Inclusive and exclusive cross sections for multiple ionization by fast, highly charged ions in the independent-electron approximation
Ben-Itzhak, I.; Gray, T.J.; Legg, J.C.; McGuire, J.H.
1988-01-01
Cross sections for the ionization of n of N electrons with equal single-electron ionization probability P are considered. When both N and the projectile charge q are large, the cross sections for single and double ionization are both found to be approximately linear in q at 1 MeVamu. The ratio of double-to-single-ionization cross sections is independent of q. Moreover, first-order perturbation theory for the single-electron ionization probability P, which varies as q 2 , is found to be applicable due to the damping of contributions with large P caused by factors of (1-P)/sup N/ - /sup n/. For large P there are differences between the inclusive probability P and the probability NP commonly used for a target with N electrons. Both of these probabilities differ significantly from the exclusive probability NP(1-P)/sup N/ -1 for the ionization of only one electron. For large N and large q, the exclusive ionization probabilities for removing exactly n of the N electrons tend to be concentrated in somewhat separate ranges of impact parameters b, defining impact-parameter ''windows.'' The windows which we obtain using the quantum-mechanical semiclassical-Coulomb-approximation (SCA) probabilities are similar to those using classical Monte Carlo calculations. Model calculations, based on analytic fits to the SCA probabilities, are used to obtain approximate analytic expressions for single- and double-ionization cross sections and for the impact-parameter windows
18. Drosophila Pumilio protein contains multiple autonomous repression domains that regulate mRNAs independently of Nanos and brain tumor.
Weidmann, Chase A; Goldstrohm, Aaron C
2012-01-01
Drosophila melanogaster Pumilio is an RNA-binding protein that potently represses specific mRNAs. In developing embryos, Pumilio regulates a key morphogen, Hunchback, in collaboration with the cofactor Nanos. To investigate repression by Pumilio and Nanos, we created cell-based assays and found that Pumilio inhibits translation and enhances mRNA decay independent of Nanos. Nanos robustly stimulates repression through interactions with the Pumilio RNA-binding domain. We programmed Pumilio to recognize a new binding site, which garners repression of new target mRNAs. We show that cofactors Brain Tumor and eIF4E Homologous Protein are not obligatory for Pumilio and Nanos activity. The conserved RNA-binding domain of Pumilio was thought to be sufficient for its function. Instead, we demonstrate that three unique domains in the N terminus of Pumilio possess the major repressive activity and can function autonomously. The N termini of insect and vertebrate Pumilio and Fem-3 binding factors (PUFs) are related, and we show that corresponding regions of human PUM1 and PUM2 have repressive activity. Other PUF proteins lack these repression domains. Our findings suggest that PUF proteins have evolved new regulatory functions through protein sequences appended to their conserved PUF repeat RNA-binding domains.
19. Multiple-source multiple-harmonic active vibration control of variable section cylindrical structures: A numerical study
Liu, Jinxin; Chen, Xuefeng; Gao, Jiawei; Zhang, Xingwu
2016-12-01
Air vehicles, space vehicles and underwater vehicles, the cabins of which can be viewed as variable section cylindrical structures, have multiple rotational vibration sources (e.g., engines, propellers, compressors and motors), making the spectrum of noise multiple-harmonic. The suppression of such noise has been a focus of interests in the field of active vibration control (AVC). In this paper, a multiple-source multiple-harmonic (MSMH) active vibration suppression algorithm with feed-forward structure is proposed based on reference amplitude rectification and conjugate gradient method (CGM). An AVC simulation scheme called finite element model in-loop simulation (FEMILS) is also proposed for rapid algorithm verification. Numerical studies of AVC are conducted on a variable section cylindrical structure based on the proposed MSMH algorithm and FEMILS scheme. It can be seen from the numerical studies that: (1) the proposed MSMH algorithm can individually suppress each component of the multiple-harmonic noise with an unified and improved convergence rate; (2) the FEMILS scheme is convenient and straightforward for multiple-source simulations with an acceptable loop time. Moreover, the simulations have similar procedure to real-life control and can be easily extended to physical model platform.
20. Maternal and perinatal outcomes in pregnancies with multiple sclerosis: a case-control study.
Yalcin, Serenat Eris; Yalcin, Yakup; Yavuz, And; Akkurt, Mehmet Ozgur; Sezik, Mekin
2017-05-24
To assess whether maternal multiple sclerosis (MS) is associated with adverse pregnancy outcomes by determining the clinical course of disease during pregnancy and postpartum throughout a 10-year-period in a single tertiary center. We conducted a case-control study that included pregnancies with a definitive diagnosis of MS (n=43), matched with 100 healthy pregnant women with similar characteristics. Maternal and perinatal data were retrieved from hospital files. Groups were compared with the Mann-Whitney and χ2 tests. Logistic regression models were constructed to determine independent effects. Maternal demographic and baseline laboratory data were similar across the groups. Rates of preterm delivery, fetal growth restriction, preeclampsia, gestational diabetes, stillbirth, cesarean delivery, congenital malformation, and 5-min Apgar score were comparable (P>0.05 for all). General anesthesia during cesarean delivery (96% vs. 39%, P=0.002), urinary tract infection (UTI) (12% vs. 3%, P=0.04), low 1-min Apgar score (21% vs. 9%, P=0.04), and nonbreastfeeding (33% vs. 2%, P=0.001) were more frequent in women with MS. The low 1-min Apgar score and breastfeeding rates were independent of general anesthesia and UTI in regression models. MS during pregnancy was not associated with adverse maternal and perinatal outcomes except UTI, low 1-min Apgar scores, and decreased breastfeeding rates.
1. Energy independent scaling of the ridge and final state description of high multiplicity p +p collisions at √{s }=7 and 13 TeV
Sarkar, Debojit
2018-02-01
An energy independent scaling of the near-side ridge yield at a given multiplicity has been observed by the ATLAS and the CMS collaborations in p +p collisions at √{s }=7 and 13 TeV. Such a striking feature of the data can be successfully explained by approaches based on initial state momentum space correlation generated due to gluon saturation. In this paper, we try to examine if such a scaling is also an inherent feature of the approaches that employ strong final state interaction in p +p collisions. We find that hydrodynamical modeling of p +p collisions using EPOS 3 shows a violation of such scaling. The current study can, therefore, provide important new insights on the origin of long-range azimuthal correlations in high multiplicity p +p collisions at the LHC energies.
2. Resilience of Urban Smart Grids Involving Multiple Control Loops
2016-01-01
Intelligent control of energy distribution grids is implemented via a hierarchy of control loops with different input values and different control targets, which also work on different time-scales. This control is enabled by a bi-directional communication flow, which can be interrupted due to ICT...
3. Interpretation of Ocular Melanin Drug Binding Assays. Alternatives to the Model of Multiple Classes of Independent Sites.
Manzanares, José A; Rimpelä, Anna-Kaisa; Urtti, Arto
2016-04-04
Melanin has a high binding affinity for a wide range of drugs. The determination of the melanin binding capacity and its binding affinity are important, e.g., in the determination of the ocular drug distribution, the prediction of drug effects in the eye, and the trans-scleral drug delivery. The binding parameters estimated from a given data set vary significantly when using different isotherms or different nonlinear fitting methods. In this work, the commonly used bi-Langmuir isotherm, which assumes two classes of independent sites, is confronted with the Sips isotherm. Direct, log-log, and Scatchard plots are used, and the interpretation of the binding curves in the latter is critically analyzed. In addition to the goodness of fit, the emphasis is placed on the physical meaning of the binding parameters. The bi-Langmuir model imposes a bimodal distribution of binding energies for the sites on the melanin granules, but the actual distribution is most likely continuous and unimodal, as assumed by the Sips isotherm. Hence, the latter describes more accurately the distribution of binding energies and also the experimental results of melanin binding to drugs and metal ions. Simulations are used to show that the existence of two classes of sites cannot be confirmed on the sole basis of the shape of the binding curve in the Scatchard plot, and that serious doubts may appear on the meaning of the binding parameters of the bi-Langmuir model. Experimental results of melanin binding to chloroquine and metoprolol are used to illustrate the importance of the choice of the binding isotherm and of the method used to evaluate the binding parameters.
4. Multiple independent genetic factors at NOS1AP modulate the QT interval in a multi-ethnic population.
Dan E Arking
Full Text Available Extremes of electrocardiographic QT interval are associated with increased risk for sudden cardiac death (SCD; thus, identification and characterization of genetic variants that modulate QT interval may elucidate the underlying etiology of SCD. Previous studies have revealed an association between a common genetic variant in NOS1AP and QT interval in populations of European ancestry, but this finding has not been extended to other ethnic populations. We sought to characterize the effects of NOS1AP genetic variants on QT interval in the multi-ethnic population-based Dallas Heart Study (DHS, n = 3,072. The SNP most strongly associated with QT interval in previous samples of European ancestry, rs16847548, was the most strongly associated in White (P = 0.005 and Black (P = 3.6 x 10(-5 participants, with the same direction of effect in Hispanics (P = 0.17, and further showed a significant SNP x sex-interaction (P = 0.03. A second SNP, rs16856785, uncorrelated with rs16847548, was also associated with QT interval in Blacks (P = 0.01, with qualitatively similar results in Whites and Hispanics. In a previously genotyped cohort of 14,107 White individuals drawn from the combined Atherosclerotic Risk in Communities (ARIC and Cardiovascular Health Study (CHS cohorts, we validated both the second locus at rs16856785 (P = 7.63 x 10(-8, as well as the sex-interaction with rs16847548 (P = 8.68 x 10(-6. These data extend the association of genetic variants in NOS1AP with QT interval to a Black population, with similar trends, though not statistically significant at P<0.05, in Hispanics. In addition, we identify a strong sex-interaction and the presence of a second independent site within NOS1AP associated with the QT interval. These results highlight the consistent and complex role of NOS1AP genetic variants in modulating QT interval.
5. Finite Control Set Model Predictive Control for Multiple Distributed Generators Microgrids
Babqi, Abdulrahman Jamal
This dissertation proposes two control strategies for AC microgrids that consist of multiple distributed generators (DGs). The control strategies are valid for both grid-connected and islanded modes of operation. In general, microgrid can operate as a stand-alone system (i.e., islanded mode) or while it is connected to the utility grid (i.e., grid connected mode). To enhance the performance of a micrgorid, a sophisticated control scheme should be employed. The control strategies of microgrids can be divided into primary and secondary controls. The primary control regulates the output active and reactive powers of each DG in grid-connected mode as well as the output voltage and frequency of each DG in islanded mode. The secondary control is responsible for regulating the microgrid voltage and frequency in the islanded mode. Moreover, it provides power sharing schemes among the DGs. In other words, the secondary control specifies the set points (i.e. reference values) for the primary controllers. In this dissertation, Finite Control Set Model Predictive Control (FCS-MPC) was proposed for controlling microgrids. FCS-MPC was used as the primary controller to regulate the output power of each DG (in the grid-connected mode) or the voltage of the point of DG coupling (in the islanded mode of operation). In the grid-connected mode, Direct Power Model Predictive Control (DPMPC) was implemented to manage the power flow between each DG and the utility grid. In the islanded mode, Voltage Model Predictive Control (VMPC), as the primary control, and droop control, as the secondary control, were employed to control the output voltage of each DG and system frequency. The controller was equipped with a supplementary current limiting technique in order to limit the output current of each DG in abnormal incidents. The control approach also enabled smooth transition between the two modes. The performance of the control strategy was investigated and verified using PSCAD/EMTDC software
6. The integration of multiple independent data reveals an unusual response to Pleistocene climatic changes in the hard tick Ixodes ricinus.
Porretta, Daniele; Mastrantonio, Valentina; Mona, Stefano; Epis, Sara; Montagna, Matteo; Sassera, Davide; Bandi, Claudio; Urbanelli, Sandra
2013-03-01
In the last few years, improved analytical tools and the integration of genetic data with multiple sources of information have shown that temperate species exhibited more complex responses to ice ages than previously thought. In this study, we investigated how Pleistocene climatic changes affected the current distribution and genetic diversity of European populations of the tick Ixodes ricinus, an ectoparasite with high ecological plasticity. We first used mitochondrial and nuclear genetic markers to investigate the phylogeographic structure of the species and its Pleistocene history using coalescent-based methods; then we used species distribution modelling to infer the climatic niche of the species at last glacial maximum; finally, we reviewed the literature on the I. ricinus hosts to identify the locations of their glacial refugia. Our results support the scenario that during the last glacial phase, I. ricinus never experienced a prolonged allopatric divergence in separate glacial refugia, but persisted with interconnected populations across Southern and Central Europe. The generalist behaviour in host choice of I. ricinus would have played a major role in maintaining connections between its populations. Although most of the hosts persisted in separate refugia, from the point of view of I. ricinus, they represented a continuity of 'bridges' among populations. Our study highlights the importance of species-specific ecology in affecting responses to Pleistocene glacial-interglacial cycles. Together with other cases in Europe and elsewhere, it contributes to setting new hypotheses on how species with wide ecological plasticity coped with Pleistocene climatic changes. © 2013 Blackwell Publishing Ltd.
7. Review on Control of DC Microgrids and Multiple Microgrid Clusters
Meng, Lexuan; Shafiee, Qobad; Ferrari-Trecate, Giancarlo
2017-01-01
This paper performs an extensive review on control schemes and architectures applied to DC microgrids. It covers multi-layer hierarchical control schemes, coordinated control strategies, plug-and-play operations, stability and active damping aspects as well as nonlinear control algorithms....... Islanding detection, protection and microgrid clusters control are also briefly summarized. All the mentioned issues are discussed with the goal of providing control design guidelines for DC microgrids. The future research challenges, from the authors’ point of view, are also provided in the final...
8. Low Wind Speed Turbine Project Conceptual Design Study: Advanced Independent Pitch Control; July 30, 2002--July 31, 2004 (Revised)
Olsen, T.; Lang, E.; Hansen, A.C.; Cheney, M. C.; Quandt, G.; VandenBosche, J.; Meyer, T.
2004-12-01
AES conducted a conceptual study of independent pitch control using inflow angle sensors. The control strategy combined input from turbine states (rotor speed, rotor azimuth, each blade pitch) with inflow angle measurements (each blade angle of attack at station 11 of 15) to derive blade pitch demand signals. The controller reduced loads sufficiently to allow a 10% rotor extension and reduce COE by 6.3%.
9. Automatic diagnosis of multiple alarms for reactor-control rooms
Gimmy, K.L.; Nomm, E.
1981-01-01
A system has been developed at the Savannah River Plant to help reactor operators respond to multiple alarms in a developing incident situation. The need for such systems has become evident in recent years, particularly after the three Mile Island incident
10. Immunochip analyses identify a novel risk locus for primary biliary cirrhosis at 13q14, multiple independent associations at four established risk loci and epistasis between 1p31 and 7q32 risk variants
Juran, Brian D.; Hirschfield, Gideon M.; Invernizzi, Pietro; Atkinson, Elizabeth J.; Li, Yafang; Xie, Gang; Kosoy, Roman; Ransom, Michael; Sun, Ye; Bianchi, Ilaria; Schlicht, Erik M.; Lleo, Ana; Coltescu, Catalina; Bernuzzi, Francesca; Podda, Mauro; Lammert, Craig; Shigeta, Russell; Chan, Landon L.; Balschun, Tobias; Marconi, Maurizio; Cusi, Daniele; Heathcote, E. Jenny; Mason, Andrew L.; Myers, Robert P.; Milkiewicz, Piotr; Odin, Joseph A.; Luketic, Velimir A.; Bacon, Bruce R.; Bodenheimer, Henry C.; Liakina, Valentina; Vincent, Catherine; Levy, Cynthia; Franke, Andre; Gregersen, Peter K.; Bossa, Fabrizio; Gershwin, M. Eric; deAndrade, Mariza; Amos, Christopher I.; Lazaridis, Konstantinos N.; Seldin, Michael F.; Siminovitch, Katherine A.
2012-01-01
To further characterize the genetic basis of primary biliary cirrhosis (PBC), we genotyped 2426 PBC patients and 5731 unaffected controls from three independent cohorts using a single nucleotide polymorphism (SNP) array (Immunochip) enriched for autoimmune disease risk loci. Meta-analysis of the genotype data sets identified a novel disease-associated locus near the TNFSF11 gene at 13q14, provided evidence for association at six additional immune-related loci not previously implicated in PBC and confirmed associations at 19 of 22 established risk loci. Results of conditional analyses also provided evidence for multiple independent association signals at four risk loci, with haplotype analyses suggesting independent SNP effects at the 2q32 and 16p13 loci, but complex haplotype driven effects at the 3q25 and 6p21 loci. By imputing classical HLA alleles from this data set, four class II alleles independently contributing to the association signal from this region were identified. Imputation of genotypes at the non-HLA loci also provided additional associations, but none with stronger effects than the genotyped variants. An epistatic interaction between the IL12RB2 risk locus at 1p31and the IRF5 risk locus at 7q32 was also identified and suggests a complementary effect of these loci in predisposing to disease. These data expand the repertoire of genes with potential roles in PBC pathogenesis that need to be explored by follow-up biological studies. PMID:22936693
11. Presentation of Malaria Epidemics Using Multiple Optimal Controls
Abid Ali Lashari
2012-01-01
Full Text Available An existing model is extended to assess the impact of some antimalaria control measures, by re-formulating the model as an optimal control problem. This paper investigates the fundamental role of three type of controls, personal protection, treatment, and mosquito reduction strategies in controlling the malaria. We work in the nonlinear optimal control framework. The existence and the uniqueness results of the solution are discussed. A characterization of the optimal control via adjoint variables is established. The optimality system is solved numerically by a competitive Gauss-Seidel-like implicit difference method. Finally, numerical simulations of the optimal control problem, using a set of reasonable parameter values, are carried out to investigate the effectiveness of the proposed control measures.
12. 29 CFR 794.116 - “Independently * * * controlled.”
2010-07-01
... STANDARDS ACT Exemption From Overtime Pay Requirements Under Section 7(b)(3) of the Act âindependently Owned... wholesale or bulk distribution of petroleum products enters into franchise or other arrangements which have...
13. DC Brushless Motor Control Design and Preliminary Testing for Independent 4-Wheel Drive Rev-11 Robotic Platform
Roni Permana Saputra
2012-03-01
Full Text Available This paper discusses the design of control system for brushless DC motor using microcontroller ATMega 16 that will be applied to an independent 4-wheel drive Mobile Robot LIPI version 2 (REV-11. The control system consists of two parts which are brushless DC motor control module and supervisory control module that coordinates the desired command to the motor control module. To control the REV-11 platform, supervisory control transmit the reference data of speed and direction of motor to control the speed and direction of each actuator on the platform REV-11. From the test results it is concluded that the designed control system work properly to coordinate and control the speed and direction of motion of the actuator motor REV-11 platform.
14. Independent regulatory control and monitoring of the environment at the uranium legacy sites under reclamation
Shandala, N.K.; Titov, A.V.; Kiselev, S.M.; Isaev, D.V.; Aladova, R.A.
2012-01-01
15. Transfer matrix method for dynamics modeling and independent modal space vibration control design of linear hybrid multibody system
Rong, Bao; Rui, Xiaoting; Lu, Kun; Tao, Ling; Wang, Guoping; Ni, Xiaojun
2018-05-01
In this paper, an efficient method of dynamics modeling and vibration control design of a linear hybrid multibody system (MS) is studied based on the transfer matrix method. The natural vibration characteristics of a linear hybrid MS are solved by using low-order transfer equations. Then, by constructing the brand-new body dynamics equation, augmented operator and augmented eigenvector, the orthogonality of augmented eigenvector of a linear hybrid MS is satisfied, and its state space model expressed in each independent model space is obtained easily. According to this dynamics model, a robust independent modal space-fuzzy controller is designed for vibration control of a general MS, and the genetic optimization of some critical control parameters of fuzzy tuners is also presented. Two illustrative examples are performed, which results show that this method is computationally efficient and with perfect control performance.
16. Load-Independent Harmonic Mitigation in SCR-Fed Three-Phase Multiple Adjustable Speed Drive Systems with Deliberately Dispatched Firing Angles
Yang, Yongheng; Davari, Pooya; Blaabjerg, Frede
2018-01-01
Adjustable speed drives (ASD) are widely used in industry for energy savings, where low-cost diode rectifiers are still employed as the front-ends, also for simplicity in control and reliability in operation. However, significant harmonics appear at the grid, which should be tackled according...... a harmonic mitigation strategy for multiple ASD systems, where silicon-controlled rectifiers (SCR) with boost converters in the dc-link have been adopted to increase the harmonic-current controllability. More specific, the SCR firing angles are deliberately dispatched among the drive units, which results...
17. Retinal Cell Death Caused by Sodium Iodate Involves Multiple Caspase-Dependent and Caspase-Independent Cell-Death Pathways
Jasmin Balmer
2015-07-01
Full Text Available Herein, we have investigated retinal cell-death pathways in response to the retina toxin sodium iodate (NaIO3 both in vivo and in vitro. C57/BL6 mice were treated with a single intravenous injection of NaIO3 (35 mg/kg. Morphological changes in the retina post NaIO3 injection in comparison to untreated controls were assessed using electron microscopy. Cell death was determined by TdT-mediated dUTP-biotin nick end labeling (TUNEL staining. The activation of caspases and calpain was measured using immunohistochemistry. Additionally, cytotoxicity and apoptosis in retinal pigment epithelial (RPE cells, primary retinal cells, and the cone photoreceptor (PRC cell line 661W were assessed in vitro after NaIO3 treatment using the ApoToxGlo™ assay. The 7-AAD/Annexin-V staining was performed and necrostatin (Nec-1 was administered to the NaIO3-treated cells to confirm the results. In vivo, degenerating RPE cells displayed a rounded shape and retracted microvilli, whereas PRCs featured apoptotic nuclei. Caspase and calpain activity was significantly upregulated in retinal sections and protein samples from NaIO3-treated animals. In vitro, NaIO3 induced necrosis in RPE cells and apoptosis in PRCs. Furthermore, Nec-1 significantly decreased NaIO3-induced RPE cell death, but had no rescue effect on treated PRCs. In summary, several different cell-death pathways are activated in retinal cells as a result of NaIO3.
18. Multiple Estimation Architecture in Discrete-Time Adaptive Mixing Control
Simone Baldi
2013-05-01
Full Text Available Adaptive mixing control (AMC is a recently developed control scheme for uncertain plants, where the control action coming from a bank of precomputed controller is mixed based on the parameter estimates generated by an on-line parameter estimator. Even if the stability of the control scheme, also in the presence of modeling errors and disturbances, has been shown analytically, its transient performance might be sensitive to the initial conditions of the parameter estimator. In particular, for some initial conditions, transient oscillations may not be acceptable in practical applications. In order to account for such a possible phenomenon and to improve the learning capability of the adaptive scheme, in this paper a new mixing architecture is developed, involving the use of parallel parameter estimators, or multi-estimators, each one working on a small subset of the uncertainty set. A supervisory logic, using performance signals based on the past and present estimation error, selects the parameter estimate to determine the mixing of the controllers. The stability and robustness properties of the resulting approach, referred to as multi-estimator adaptive mixing control (Multi-AMC, are analytically established. Besides, extensive simulations demonstrate that the scheme improves the transient performance of the original AMC with a single estimator. The control scheme and the analysis are carried out in a discrete-time framework, for easier implementation of the method in digital control.
19. Multiple Model Adaptive Control Using Dual Youla-Kucera Factorisation
Bendtsen, Jan Dimon; Trangbæk, Klaus
2012-01-01
We propose a multi-model adaptive control scheme for uncertain linear plants based on the concept of model unfalsification. The approach relies on examining the ability of a pre-computed set of plant-controller candidates and choosing the one that is best able to reproduce observed in- and output...
20. Temporal interference with frequency-controllable long photons from independent cold atomic sources
Qian, Peng; Gu, Zhenjie; Wen, Rong; Zhang, Weiping; Chen, J. F.
2018-01-01
The interference of single photons from independent sources is an essential tool in quantum information processing. However, the interfering of photons with long temporal states in a time-resolved manner has rarely been studied. This is because without transmitting spectral filters or coupling to a cavity mode single photons generated in traditional nonlinear crystals suffer from a short temporal profile below 1 ns. With spectral correlation maintained in the biphotons generated from spontaneous four-wave mixing process in cold atom clouds, here we demonstrate the temporal interference of two frequency-tunable long photons from two independent cold atomic sources. We observe and analyze the interference of frequency-mismatched photons, where the phenomenon of the quantum beat at megahertz separation is displayed. Our paper provides more details for the quantum beat of two independent narrow-band single photons, which may find potential application in frequency-encoded photonic qubits in quantum information processing.
1. Circadian phase resetting via single and multiple control targets.
Neda Bagheri
2008-07-01
Full Text Available Circadian entrainment is necessary for rhythmic physiological functions to be appropriately timed over the 24-hour day. Disruption of circadian rhythms has been associated with sleep and neuro-behavioral impairments as well as cancer. To date, light is widely accepted to be the most powerful circadian synchronizer, motivating its use as a key control input for phase resetting. Through sensitivity analysis, we identify additional control targets whose individual and simultaneous manipulation (via a model predictive control algorithm out-perform the open-loop light-based phase recovery dynamics by nearly 3-fold. We further demonstrate the robustness of phase resetting by synchronizing short- and long-period mutant phenotypes to the 24-hour environment; the control algorithm is robust in the presence of model mismatch. These studies prove the efficacy and immediate application of model predictive control in experimental studies and medicine. In particular, maintaining proper circadian regulation may significantly decrease the chance of acquiring chronic illness.
2. Independent control of arbitrary orders of dispersion at the high power end of CPA lasers
Goerbe, M.; Jojart, P.; Szeged University, Szeged; Kovacs, M.; Osvay, K.
2010-01-01
were designed and examined carefully. The first doublet consisted on an N-PK51 and a Lithosil-Q1E193 wedge and was designed to CEP tuning, the second one from N-SSK2 and N-LaK7 aimed to change the GDD only. The measured tuning slopes were 1.66 rad/nm and 3.6 fs 2 /mm, respectively. The triplet compiled of N-LaK7, N-LaSF46 and NSF57 wedges was made for TOD tuning: 130 fs 3 /mm was measured. All wedge assemblies only changed the selected spectral phase derivative while keeping the others practically zero. The residual angular dispersion was also measured, and found to be well below the detection limit of 0.2 μrad/nm. We have proved that a combination of optical wedges is capable to control the required order of dispersion, including CEP, independently to all the other orders. Since the loss is negligible and the (bulk) damage threshold is high, we believe that such specially designed wedge combinations can significantly contribute to the fine tuning of dispersion and CEP just prior to the compressor of high power laser systems like Petawatt Field Syntheser (PFS), Extreme Light Infrastructure (ELI), but also of smaller scale laboratory few cycle systems.
3. Independent control of metal cluster and ceramic particle characteristics during one-step synthesis of Pt/TiO2
Schulz, H.; Madler, L.; Strobel, R.
2005-01-01
Rapid quenching during flame spray synthesis of Pt/TiO2 (0-10 Wt% Pt) is demonstrated as a versatile method for independent control of support (TiO2) and noble metal (Pt)cluster characteristics. Titania grain size, morphology, crystal phase structure, and crystal size were analyzed by nitrogen ad...
4. Efficient Control Law Simulation for Multiple Mobile Robots
Driessen, B.J.; Feddema, J.T.; Kotulski, J.D.; Kwok, K.S.
1998-10-06
In this paper we consider the problem of simulating simple control laws involving large numbers of mobile robots. Such simulation can be computationally prohibitive if the number of robots is large enough, say 1 million, due to the 0(N2 ) cost of each time step. This work therefore uses hierarchical tree-based methods for calculating the control law. These tree-based approaches have O(NlogN) cost per time step, thus allowing for efficient simulation involving a large number of robots. For concreteness, a decentralized control law which involves only the distance and bearing to the closest neighbor robot will be considered. The time to calculate the control law for each robot at each time step is demonstrated to be O(logN).
5. Dynamic pipe control with a multiple digit automatic measuring device
Jenzer, P.
1984-01-01
With the flow rotating method, thin-walled pipes can be produced with very tight tolerances and high mechanical sturdiness. The measuring device permits a dynamic control of these pipes, the outer diameter of which can lie between 70 and 300 mm, the length between 500 and 2000 mm and the wall thickness between 0,5 and 10 mm. Depending on the pipe type, up to 27 measurements in a maximum of 5 measuring levels are to be controlled. (orig.) [de
6. The design of robust independence multivariable controller for robot manipulator using inverse dynamics
Han, Sung Hyun
1993-01-01
This paper proposes a new approach to the design of multivariable control schemes for assembly robot manipulator to achieve accuracy trajectory tracking by joint angles. The proposed control scheme consists of a multivariable feedforward controller and a feedback controller. In this control scheme, the feedback controller is proportional integral-derivative type and is designed to achieve the pole placement. The feedforward controller is the inverse of the linealized model of robot manipulator dynamics. The feedback controller ensures that each joint tracks any reference trajectory. The proposed robot controller scheme has a computationally efficient schemes for either offline gain scheduling or online gain computation to account for variations in the linealized robot dynamic model due to changes in operating point. The simulation results demonstrate that the proposed control schemesperporms remarkably well for parameter uncertainties and load variations. (Author)
7. Hierarchical Control for Multiple DC-Microgrids Clusters
Shafiee, Qobad; Dragicevic, Tomislav; Vasquez, Juan Carlos
2014-01-01
DC microgrids (MGs) have gained research interest during the recent years because of many potential advantages as compared to the ac system. To ensure reliable operation of a low-voltage dc MG as well as its intelligent operation with the other DC MGs, a hierarchical control is proposed in this p......DC microgrids (MGs) have gained research interest during the recent years because of many potential advantages as compared to the ac system. To ensure reliable operation of a low-voltage dc MG as well as its intelligent operation with the other DC MGs, a hierarchical control is proposed...
8. Cooperative Control for Multiple Autonomous Vehicles Using Descriptor Functions
Marta Niccolini
2014-01-01
Full Text Available The paper presents a novel methodology for the control management of a swarm of autonomous vehicles. The vehicles, or agents, may have different skills, and be employed for different missions. The methodology is based on the definition of descriptor functions that model the capabilities of the single agent and each task or mission. The swarm motion is controlled by minimizing a suitable norm of the error between agents’ descriptor functions and other descriptor functions which models the entire mission. The validity of the proposed technique is tested via numerical simulation, using different task assignment scenarios.
9. 'Compromise position' image alignment to accommodate independent motion of multiple clinical target volumes during radiotherapy: A high risk prostate cancer example
Rosewall, Tara; Alasti, Hamideh; Bayley, Andrew; Yan, Jing
2017-01-01
Inclusion of multiple independently moving clinical target volumes (CTVs) in the irradiated volume causes an image guidance conundrum. The purpose of this research was to use high risk prostate cancer as a clinical example to evaluate a 'compromise' image alignment strategy. The daily pre-treatment orthogonal EPI for 14 consecutive patients were included in this analysis. Image matching was performed by aligning to the prostate only, the bony pelvis only and using the 'compromise' strategy. Residual CTV surrogate displacements were quantified for each of the alignment strategies. Analysis of the 388 daily fractions indicated surrogate displacements were well-correlated in all directions (r 2 = 0.95 (LR), 0.67 (AP) and 0.59 (SI). Differences between the surrogates displacements (95% range) were −0.4 to 1.8 mm (LR), −1.2 to 5.2 mm (SI) and −1.2 to 5.2 mm (AP). The distribution of the residual displacements was significantly smaller using the 'compromise' strategy, compared to the other strategies (p 0.005). The 'compromise' strategy ensured the CTV was encompassed by the PTV in all fractions, compared to 47 PTV violations when aligned to prostate only. This study demonstrated the feasibility of a compromise position image guidance strategy to accommodate simultaneous displacements of two independently moving CTVs. Application of this strategy was facilitated by correlation between the CTV displacements and resulted in no geometric excursions of the CTVs beyond standard sized PTVs. This simple image guidance strategy may also be applicable to other disease sites that concurrently irradiate multiple CTVs, such as head and neck, lung and cervix cancer.
10. Combining multiple hypothesis testing and affinity propagation clustering leads to accurate, robust and sample size independent classification on gene expression data
Sakellariou Argiris
2012-10-01
Full Text Available Abstract Background A feature selection method in microarray gene expression data should be independent of platform, disease and dataset size. Our hypothesis is that among the statistically significant ranked genes in a gene list, there should be clusters of genes that share similar biological functions related to the investigated disease. Thus, instead of keeping N top ranked genes, it would be more appropriate to define and keep a number of gene cluster exemplars. Results We propose a hybrid FS method (mAP-KL, which combines multiple hypothesis testing and affinity propagation (AP-clustering algorithm along with the Krzanowski & Lai cluster quality index, to select a small yet informative subset of genes. We applied mAP-KL on real microarray data, as well as on simulated data, and compared its performance against 13 other feature selection approaches. Across a variety of diseases and number of samples, mAP-KL presents competitive classification results, particularly in neuromuscular diseases, where its overall AUC score was 0.91. Furthermore, mAP-KL generates concise yet biologically relevant and informative N-gene expression signatures, which can serve as a valuable tool for diagnostic and prognostic purposes, as well as a source of potential disease biomarkers in a broad range of diseases. Conclusions mAP-KL is a data-driven and classifier-independent hybrid feature selection method, which applies to any disease classification problem based on microarray data, regardless of the available samples. Combining multiple hypothesis testing and AP leads to subsets of genes, which classify unknown samples from both, small and large patient cohorts with high accuracy.
11. Development of a flattening filter free multiple source model for use as an independent, Monte Carlo, dose calculation, quality assurance tool for clinical trials.
Faught, Austin M; Davidson, Scott E; Popple, Richard; Kry, Stephen F; Etzel, Carol; Ibbott, Geoffrey S; Followill, David S
2017-09-01
The Imaging and Radiation Oncology Core-Houston (IROC-H) Quality Assurance Center (formerly the Radiological Physics Center) has reported varying levels of compliance from their anthropomorphic phantom auditing program. IROC-H studies have suggested that one source of disagreement between institution submitted calculated doses and measurement is the accuracy of the institution's treatment planning system dose calculations and heterogeneity corrections used. In order to audit this step of the radiation therapy treatment process, an independent dose calculation tool is needed. Monte Carlo multiple source models for Varian flattening filter free (FFF) 6 MV and FFF 10 MV therapeutic x-ray beams were commissioned based on central axis depth dose data from a 10 × 10 cm 2 field size and dose profiles for a 40 × 40 cm 2 field size. The models were validated against open-field measurements in a water tank for field sizes ranging from 3 × 3 cm 2 to 40 × 40 cm 2 . The models were then benchmarked against IROC-H's anthropomorphic head and neck phantom and lung phantom measurements. Validation results, assessed with a ±2%/2 mm gamma criterion, showed average agreement of 99.9% and 99.0% for central axis depth dose data for FFF 6 MV and FFF 10 MV models, respectively. Dose profile agreement using the same evaluation technique averaged 97.8% and 97.9% for the respective models. Phantom benchmarking comparisons were evaluated with a ±3%/2 mm gamma criterion, and agreement averaged 90.1% and 90.8% for the respective models. Multiple source models for Varian FFF 6 MV and FFF 10 MV beams have been developed, validated, and benchmarked for inclusion in an independent dose calculation quality assurance tool for use in clinical trial audits. © 2017 American Association of Physicists in Medicine.
12. 'Compromise position' image alignment to accommodate independent motion of multiple clinical target volumes during radiotherapy: A high risk prostate cancer example.
Rosewall, Tara; Yan, Jing; Alasti, Hamideh; Cerase, Carla; Bayley, Andrew
2017-04-01
Inclusion of multiple independently moving clinical target volumes (CTVs) in the irradiated volume causes an image guidance conundrum. The purpose of this research was to use high risk prostate cancer as a clinical example to evaluate a 'compromise' image alignment strategy. The daily pre-treatment orthogonal EPI for 14 consecutive patients were included in this analysis. Image matching was performed by aligning to the prostate only, the bony pelvis only and using the 'compromise' strategy. Residual CTV surrogate displacements were quantified for each of the alignment strategies. Analysis of the 388 daily fractions indicated surrogate displacements were well-correlated in all directions (r 2 = 0.95 (LR), 0.67 (AP) and 0.59 (SI). Differences between the surrogates displacements (95% range) were -0.4 to 1.8 mm (LR), -1.2 to 5.2 mm (SI) and -1.2 to 5.2 mm (AP). The distribution of the residual displacements was significantly smaller using the 'compromise' strategy, compared to the other strategies (p 0.005). The 'compromise' strategy ensured the CTV was encompassed by the PTV in all fractions, compared to 47 PTV violations when aligned to prostate only. This study demonstrated the feasibility of a compromise position image guidance strategy to accommodate simultaneous displacements of two independently moving CTVs. Application of this strategy was facilitated by correlation between the CTV displacements and resulted in no geometric excursions of the CTVs beyond standard sized PTVs. This simple image guidance strategy may also be applicable to other disease sites that concurrently irradiate multiple CTVs, such as head and neck, lung and cervix cancer. © 2016 The Royal Australian and New Zealand College of Radiologists.
13. Multiple Model Adaptive Attitude Control of LEO Satellite with Angular Velocity Constraints
2018-04-01
In this paper, the multiple model adaptive control is utilized to improve the transient response of attitude control system for a rigid spacecraft. An adaptive output feedback control law is proposed for attitude control under angular velocity constraints and its almost global asymptotic stability is proved. The multiple model adaptive control approach is employed to counteract large uncertainty in parameter space of the inertia matrix. The nonlinear dynamics of a low earth orbit satellite is simulated and the proposed control algorithm is implemented. The reported results show the effectiveness of the suggested scheme.
14. An agent-based negotiation approach for balancing multiple coupled control domains
Umair, Aisha; Clausen, Anders; Jørgensen, Bo Nørregaard
2015-01-01
Solving multi-objective multi-issue negotiation problems involving interdependent issues distributed among multiple control domains is inherent to most non-trivial cyber-physical systems. In these systems, the coordinated operation of interconnected subsystems performing autonomous control....... The proposed approach can solve negotiation problems with interdependent issues across multiple coupled control domains. We demonstrate our approach by solving a coordination problem where a Combined Heat and Power Plant must allocate electricity for three commercial greenhouses to ensure the required plant...
15. Synthesis for robust synchronization of chaotic systems under output feedback control with multiple random delays
Wen Guilin; Wang Qingguo; Lin Chong; Han Xu; Li Guangyao
2006-01-01
Synchronization under output feedback control with multiple random time delays is studied, using the paradigm in nonlinear physics-Chua's circuit. Compared with other synchronization control methods, output feedback control with multiple random delay is superior for a realistic synchronization application to secure communications. Sufficient condition for global stability of delay-dependent synchronization is established based on the LMI technique. Numerical simulations fully support the analytical approach, in spite of the random delays
16. Co-administration of Albendazole and Levamisole to control multiple ...
Albendazole (ABZ) and levamisole (LEV) were co-administered to evaluate their ability to control natural helminth infections in a sheep farm where resistance to the individual anthelmintic had previously been reported. Thirty two sheep of mixed ages and sex were randomly allocated to four equal groups. Group 1 and 2 ...
17. Multiple Primary LED Lamp Colour Controller with Inherent Brightness Limitation
Barcena, R.; Ackermann, B.
2007-01-01
There is a strong interest in using LEDs for general illumination due to the potential they offer for energy saving, environmental friendliness, new opportunities in lighting design, and control of the intensity, colour, and spatial distribution of light. General illumination requires primarily
18. Quality control for retinal OCT in multiple sclerosis
Schippling, S; Balk, Lj; Costello, F
2015-01-01
to provide guidance on the use of validated quality control (QC) criteria for the use of OCT in MS research and clinical trials. METHODS: A prospective multi-centre (n = 13) study. Peripapillary ring scan QC rating of an OCT training set (n = 50) was followed by a test set (n = 50). Inter-rater agreement...
19. MANAGEMENT CONTROL SYSTEMS: A REVIEW OF THEIR COMPONENTS AND THEIR UNDERLYING INDEPENDENCE
Boghean Florin
2013-07-01
The organization of the internal control system in a manner that is divergent with the principles of planned economy has led managers to believe that control activities are discretionary, and the subsequent lack of management responsibility has weakened the efficiency of internal control systems during the first years after 1989.
20. Independent Children's Social Work Practice Pilots: Evaluating Practitioners' Job Control and Burnout
Hussein, Shereen; Manthorpe, Jill; Ridley, Julie; Austerberry, Helen; Farrelly, Nicola; Larkins, Cath; Bilson, Andy; Stanley, Nicky
2014-01-01
Objectives: To investigate whether a new model that delegates some out-of-home care services from the public to the private and not-for-profit sectors in England enhances practitioners' job control and stress levels. Methods: A 3-year longitudinal matched-control evaluation examined changes in Karasek demand-control model and Maslach burnout…
1. Controls of Multiple Stressors on the Black Sea Fishery
Temel Oguz
2017-04-01
Full Text Available Black Sea is one of the most severely degraded and exploited large marine ecosystems in the world. For the last 50 years after the depletion of large predatory fish stocks, anchovy (with the partial contribution of sprat has been acting as the main top predator species and experienced a major stock collapse at the end of 1990s. After the collapse, eastern part of the southern Black Sea became the only region sustaining relatively high anchovy catch (400,000 tons whereas the total catch within the rest of the sea was reduced to nearly its one-third. The lack of recovery of different fish stocks under a slow ecosystem rehabilitation may be attributed, on the one hand, to inappropriate management measures and the lack of harmonized fishery policy among the riparian countries. On the other hand, impacts of multiple stressors (eutrophication, alien species invasions, natural climatic variations on the food web may contribute to resilience of the system toward its recovery. The overfishing/recovery problem therefore cannot be isolated from rehabilitation efforts devoted to the long-term chronic degradation of the food web structure, and alternative fishery-related management measures must be adopted as a part of a comprehensive ecosystem-based management strategy. The present study provides a data-driven ecosystem assessment, underlines the key environmental issues and threats, and points to the critical importance of holistic approach to resolve the fishery-ecosystem interactions. It also stresses the transboundary nature of the problem.
2. Optimal Testing Effort Control for Modular Software System Incorporating The Concept of Independent and Dependent Faults: A Control Theoretic Approach
Kuldeep CHAUDHARY
2012-07-01
Full Text Available In this paper, we discuss modular software system for Software Reliability GrowthModels using testing effort and study the optimal testing effort intensity for each module. The maingoal is to minimize the cost of software development when budget constraint on testing expenditureis given. We discuss the evolution of faults removal dynamics in incorporating the idea of leading/independent and dependent faults in modular software system under the assumption that testing ofeach of the modulus is done independently. The problem is formulated as an optimal controlproblem and the solution to the proposed problem has been obtained by using Pontryagin MaximumPrinciple.
3. Multiple large solar lentigos on the upper back as clinical markers of past severe sunburn: a case-control study.
Derancourt, C; Bourdon-Lanoy, E; Grob, J-J; Guillaume, J-C; Bernard, P; Bastuji-Garin, S
2007-01-01
Multiple solar lentigos commonly seen on the upper back and shoulders of adults are classically considered as a sign of photodamage, although epidemiological studies are scarce. To assess whether these lesions are clinical markers of past severe sunburn. A case-control study in two outpatient dermatology clinics in French university hospitals. Past episodes of moderate and severe sunburn were compared between 145 adult patients with multiple solar lentigos on the upper back and 145 matched controls. In multivariate analysis adjusted for potential confounders, recalled episodes of sunburn during childhood, adolescence and adulthood were independently associated with the presence of multiple solar lentigos (adjusted odds ratios, 95% confidence intervals: 2.3 (1.1-5.2) and 28.1 (10.4-75.6) for moderate and severe sunburn, respectively). Multiple solar lentigos on the upper back and shoulders of adults are potential clinical markers of past severe sunburn which may thus be used to identify a population at higher risk of developing cutaneous malignant melanoma.
4. Pointright: a system to redirect mouse and keyboard control among multiple machines
Johanson, Bradley E [Palo Alto, CA; Winograd, Terry A [Stanford, CA; Hutchins, Gregory M [Mountain View, CA
2008-09-30
The present invention provides a software system, PointRight, that allows for smooth and effortless control of pointing and input devices among multiple displays. With PointRight, a single free-floating mouse and keyboard can be used to control multiple screens. When the cursor reaches the edge of a screen it seamlessly moves to the adjacent screen and keyboard control is simultaneously redirected to the appropriate machine. Laptops may also redirect their keyboard and pointing device, and multiple pointers are supported simultaneously. The system automatically reconfigures itself as displays go on, go off, or change the machine they display.
5. A Neural Network Combined Inverse Controller for a Two-Rear-Wheel Independently Driven Electric Vehicle
Duo Zhang
2014-07-01
Full Text Available Vehicle active safety control is attracting ever increasing attention in the attempt to improve the stability and the maneuverability of electric vehicles. In this paper, a neural network combined inverse (NNCI controller is proposed, incorporating the merits of left-inversion and right-inversion. As the left-inversion soft-sensor can estimate the sideslip angle, while the right-inversion is utilized to decouple control. Then, the proposed NNCI controller not only linearizes and decouples the original nonlinear system, but also directly obtains immeasurable state feedback in constructing the right-inversion. Hence, the proposed controller is very practical in engineering applications. The proposed system is co-simulated based on the vehicle simulation package CarSim in connection with Matlab/Simulink. The results verify the effectiveness of the proposed control strategy.
6. Improvement in C-reactive protein and advanced glycosylation end-products in poorly controlled diabetics is independent of glucose control.
Md Isa, S H; Najihah, I; Nazaimoon, W M Wan; Kamarudin, N A; Umar, N A; Mat, N H; Khalid, B A K
2006-04-01
We studied the efficacy of four different treatment regimens (sulphonylurea and metformin+/-acarbose versus glimepiride and rosiglitazone versus glimepiride and bedtime NPH insulin versus multiple actrapid and NPH insulin injections) in poorly controlled type 2 diabetes subjects on hs-CRP, VCAM-1 and AGE at 4, 8 and 12 weeks of treatment. Multiple insulin injections rapidly improved HbA(1c) by 0.6+/-0.9% (pimprovement in blood glucose. AGE improved in all groups irrespective of type of treatment, glycaemic control and CRP levels. Our data indicate rapid glycaemic control alone does not necessarily result in improvement in markers of inflammation in type 2 diabetes patients.
7. Cohesive Motion Control Algorithm for Formation of Multiple Autonomous Agents
Debabrata Atta
2010-01-01
Full Text Available This paper presents a motion control strategy for a rigid and constraint consistent formation that can be modeled by a directed graph whose each vertex represents individual agent kinematics and each of directed edges represents distance constraints maintained by an agent, called follower, to its neighbouring agent. A rigid and constraint consistent graph is called persistent graph. A persistent graph is minimally persistent if it is persistent, and no edge can be removed without losing its persistence. An acyclic (free of cycles in its sensing pattern minimally persistent graph of Leader-Follower structure has been considered here which can be constructed from an initial Leader-Follower seed (initial graph with two vertices, one is Leader and another one is First Follower and one edge in between them is directed towards Leader by Henneberg sequence (a procedure of growing a graph containing only vertex additions. A set of nonlinear optimization-based decentralized control laws for mobile autonomous point agents in two dimensional plane have been proposed. An infinitesimal deviation in formation shape created continuous motion of Leader is compensated by corresponding continuous motion of other agents fulfilling the shortest path criteria.
8. Protocol for the effect evaluation of independent medical evaluation after six months sick leave: a randomized controlled trial of independent medical evaluation versus treatment as usual in Norway
Husabo, Elisabeth; Monstad, Karin; Holm?s, Tor Helge; Oyeflaten, Irene; Werner, Erik L.; Maeland, Silje
2017-01-01
Background It has been discussed whether the relationship between a patient on sick leave and his/her general practitioner (GP) is too close, as this may hinder the GP’s objective evaluation of need for sick leave. Independent medical evaluation involves an independent physician consulting the patient. This could lead to new perspectives on sick leave and how to follow-up the patient. Methods/design T...
9. H-infty Control of systems with multiple i/o delays
Agoes Ariffin Moelja, A.A.; Meinsma, Gjerrit; Mirkin, Leonid
2003-01-01
In this paper the standard (four-block) H-infty control problem for systems with multiple i/o delays in the feedback loop is studied. The central idea is to see the multiple delay operator as a special series connection of elementary delay operators, called the adobe delay operators. The adobe delay
10. Availability analysis of safety grade multiple redundant controller used in advanced nuclear safety systems
Son, Kwang Seop; Kim, Dong Hoon; Park, Gee Yong; Kang, Hyun Gook
2018-01-01
Highlights: •The multiple redundant controller, SPLC is configured as the combination of DMR and TMR architecture. •We construct the Markov model of SPLC using the concept of the system unavailability rate. •To satisfy the availability requirement of safety grade controller, the fault coverage factor (FCF) should be ≥0.8 and the MTTR of each module should be ≤100 h when FCF is 0.9. •The availability of SPLC is better than that of PLC having iTMR architecture however it is poorer than iTMR considering the off-line test and inspection on the assumption that MTTR of each module is ≤200 h. -- Abstract: We analyze the availability of the Safety Programmable Logic Controller (SPLC) having multiple redundant architectures. In the SPLC, input/output and processor module are configured as triple modular redundancy (TMR), and backplane bus, power and communication modules are configured as dual modular redundancy (DMR). The voting logics for redundant architectures are based on the forwarding error detection. It means that the receivers perform the voting logics based on the status information of transmitters. To analyze the availability of SPLC, we construct the Markov model and simplify the model adopting the system unavailability rate. The results show that the fault coverage factor should be ≥0.8 and Mean Time To Repair (MTTR) should be ≤100 h in order to satisfy the requirement that the availability of the safety grade PLC should be ≥0.995. Also we evaluate the availability of SPLC comparing to other PLCs such as simplex, processor DMR (pDMR) and independent TMR (iTMR) PLCs used in the existing nuclear safety systems. The availability of SPLC is higher than those of the simplex, pDMR but is lower than that of iTMR for one month which is the periodic off-line test and inspection. That’s why the number of redundant modules used in PLC is more dominant to increasing the availability than the number of fault masking methods such as voting logics used
11. Independent Control of Positive- and Negative-Sequence Current Components in a Doubly Fed Machine
Bendl, Jiří; Chomát, Miroslav; Schreier, Luděk
2005-01-01
Roč. 15, č. 3 (2005), s. 191-202 ISSN 1430-144X R&D Projects: GA ČR(CZ) GA102/03/0046 Institutional research plan: CEZ:AV0Z20570509 Keywords : vector control * adjustable speed generation systems * converter control Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.056, year: 2005
12. Dynamic Fault Diagnosis for Semi-Batch Reactor under Closed-Loop Control via Independent Radial Basis Function Neural Network
Abdelkarim M. Ertiame; D. W. Yu; D. L. Yu; J. B. Gomm
2015-01-01
In this paper, a robust fault detection and isolation (FDI) scheme is developed to monitor a multivariable nonlinear chemical process called the Chylla-Haase polymerization reactor, when it is under the cascade PI control. The scheme employs a radial basis function neural network (RBFNN) in an independent mode to model the process dynamics, and using the weighted sum-squared prediction error as the residual. The Recursive Orthogonal Least Squares algorithm (ROLS) is emplo...
13. A Chinese Herbal Medicine, Tokishakuyakusan, Reduces the Worsening of Impairments and Independence after Stroke: A 1-Year Randomized, Controlled Trial
Hirozo Goto
2011-01-01
Full Text Available In post-stroke patients, the recurrence of stroke and progression of impairments lead to a bedridden state and dementia. As for their treatments, only anti-hypertension and anti-coagulation therapies to prevent the recurrence of stroke are available. In Asia, post-stroke patients with impairments are often treated with herbal medicine. The present study evaluated the effectiveness of tokishakuyakusan (TS in improving the impairment and independence in post-stroke patients. Thirty-one post-stroke patients (mean age = 81.4 years were recruited and enrolled. Participants were randomly assigned to the TS group (n = 16 or non-treatment (control group (n = 15 and treated for 12 months. Impairments were assessed using the Stroke Impairment Assessment Set (SIAS. Independence was evaluated using the functional independence measure (FIM. For each outcome measure, mean change was calculated every 3 months. The results were that impairments according to SIAS did not significantly change in the TS group. In contrast, SIAS significantly worsened in the control group. There was a significant difference between the two groups. In each term of SIAS, affected lower extremity scores, abdominal muscle strength, function of visuospatial perception, and so forth. in the TS group were better than those in the control group. Independence according to FIM did not change significantly in the TS group. In contrast, FIM significantly worsened in the control group. There was also a significant difference between the two groups. In conclusion, TS was considered to suppress the impairments of lower limbs and to exert a favorable effect on cerebral function for post-stroke patients.
14. The Adder Phenomenon Emerges from Independent Control of Pre- and Post-Start Phases of the Budding Yeast Cell Cycle.
Chandler-Brown, Devon; Schmoller, Kurt M; Winetraub, Yonatan; Skotheim, Jan M
2017-09-25
Although it has long been clear that cells actively regulate their size, the molecular mechanisms underlying this regulation have remained poorly understood. In budding yeast, cell size primarily modulates the duration of the cell-division cycle by controlling the G1/S transition known as Start. We have recently shown that the rate of progression through Start increases with cell size, because cell growth dilutes the cell-cycle inhibitor Whi5 in G1. Recent phenomenological studies in yeast and bacteria have shown that these cells add an approximately constant volume during each complete cell cycle, independent of their size at birth. These results seem to be in conflict, as the phenomenological studies suggest that cells measure the amount they grow, rather than their size, and that size control acts over the whole cell cycle, rather than specifically in G1. Here, we propose an integrated model that unifies the adder phenomenology with the molecular mechanism of G1/S cell-size control. We use single-cell microscopy to parameterize a full cell-cycle model based on independent control of pre- and post-Start cell-cycle periods. We find that our model predicts the size-independent amount of cell growth during the full cell cycle. This suggests that the adder phenomenon is an emergent property of the independent regulation of pre- and post-Start cell-cycle periods rather than the consequence of an underlying molecular mechanism measuring a fixed amount of growth. Copyright © 2017 Elsevier Ltd. All rights reserved.
15. On the diversity of multiple optimal controls for quantum systems
Shir, O M; Baeck, Th; Beltrani, V; Rabitz, H; Vrakking, M J J
2008-01-01
This study presents simulations of optimal field-free molecular alignment and rotational population transfer (starting from the J = 0 rotational ground state of a diatomic molecule), optimized by means of laser pulse shaping guided by evolutionary algorithms. Qualitatively different solutions are obtained that optimize the alignment and population transfer efficiency to the maximum extent that is possible given the existing constraints on the optimization due to the finite bandwidth and energy of the laser pulse, the finite degrees of freedom in the laser pulse shaping and the evolutionary algorithm employed. The effect of these constraints on the optimization process is discussed at several levels, subject to theoretical as well as experimental considerations. We show that optimized alignment yields can reach extremely high values, even with severe constraints being present. The breadth of optimal controls is assessed, and a correlation is found between the diversity of solutions and the difficulty of the problem. In the pulse shapes that optimize dynamic alignment we observe a transition between pulse sequences that maximize the initial population transfer from J = 0 to J = 2 and pulse sequences that optimize the transfer to higher rotational levels
16. Multiple controls affect arsenite oxidase gene expression in Herminiimonas arsenicoxydans
Coppée Jean-Yves
2010-02-01
Full Text Available Abstract Background Both the speciation and toxicity of arsenic are affected by bacterial transformations, i.e. oxidation, reduction or methylation. These transformations have a major impact on environmental contamination and more particularly on arsenic contamination of drinking water. Herminiimonas arsenicoxydans has been isolated from an arsenic- contaminated environment and has developed various mechanisms for coping with arsenic, including the oxidation of As(III to As(V as a detoxification mechanism. Results In the present study, a differential transcriptome analysis was used to identify genes, including arsenite oxidase encoding genes, involved in the response of H. arsenicoxydans to As(III. To get insight into the molecular mechanisms of this enzyme activity, a Tn5 transposon mutagenesis was performed. Transposon insertions resulting in a lack of arsenite oxidase activity disrupted aoxR and aoxS genes, showing that the aox operon transcription is regulated by the AoxRS two-component system. Remarkably, transposon insertions were also identified in rpoN coding for the alternative N sigma factor (σ54 of RNA polymerase and in dnaJ coding for the Hsp70 co-chaperone. Western blotting with anti-AoxB antibodies and quantitative RT-PCR experiments allowed us to demonstrate that the rpoN and dnaJ gene products are involved in the control of arsenite oxidase gene expression. Finally, the transcriptional start site of the aoxAB operon was determined using rapid amplification of cDNA ends (RACE and a putative -12/-24 σ54-dependent promoter motif was identified upstream of aoxAB coding sequences. Conclusion These results reveal the existence of novel molecular regulatory processes governing arsenite oxidase expression in H. arsenicoxydans. These data are summarized in a model that functionally integrates arsenite oxidation in the adaptive response to As(III in this microorganism.
17. Independent and joint effects of tea and milk consumption on oral cancer among non-smokers and non-drinkers: a case-control study in China.
Chen, Fa; Yan, Lingjun; Lin, Lisong; Liu, Fengqiong; Qiu, Yu; Liu, Fangping; Huang, Jiangfeng; Wu, Junfeng; Cai, Lin; Cai, Guoxi; Aoyagi, Kiyoshi; He, Baochang
2017-07-25
This study aims to evaluate the independent and joint effects of tea and milk consumption on oral cancer risk among non-smokers and non-drinkers (NS/ND). A hospital-based case-control study was performed in Fujian, China. 421 cases and frequency-matched 1398 controls were included without tobacco smoking and alcohol drinking habits. Unconditional logistic regression model was used to assess the relationship of tea and milk consumption with oral cancer risk. Tea and milk consumption were significantly associated with decreased risk of oral cancer, the adjusted odds ratios (aORs) were 0.73 (95% CI: 0.54-0.97) and 0.69 (95% CI: 0.55-0.88), respectively. According to subgroup analysis, the inverse associations between tea consumption and oral cancer risk were only observed among the elders (>60 years) and urban residents. While the protect effect of milk drinking was more obvious in males, normal body mass index population (18.5-23.9), urban residents and those age ≤ 60 years. Additionally, a significantly multiplicative interaction between tea and milk consumption was observed for oral cancer risk (P = 0.001). The present study is the first to simultaneously assess the association of tea consumption and milk drinking with oral cancer risk. The results suggest that tea and milk consumption are independent protective factors for oral cancer among NS/ND, with a joint effect between them.
18. Efficient direct yaw moment control: tyre slip power loss minimisation for four-independent wheel drive vehicle
Kobayashi, Takao; Katsuyama, Etsuo; Sugiura, Hideki; Ono, Eiichi; Yamamoto, Masaki
2018-05-01
This paper proposes an efficient direct yaw moment control (DYC) capable of minimising tyre slip power loss on contact patches for a four-independent wheel drive vehicle. Simulations identified a significant power loss reduction with a direct yaw moment due to a change in steer characteristics during acceleration or deceleration while turning. Simultaneously, the vehicle motion can be stabilised. As a result, the proposed control method can ensure compatibility between vehicle dynamics performance and energy efficiency. This paper also describes the results of a full-vehicle simulation that was conducted to examine the effectiveness of the proposed DYC.
19. Semi-active control of a cable-stayed bridge under multiple-support excitations.
Dai, Ze-Bing; Huang, Jin-Zhi; Wang, Hong-Xia
2004-03-01
This paper presents a semi-active strategy for seismic protection of a benchmark cable-stayed bridge with consideration of multiple-support excitations. In this control strategy, Magnetorheological (MR) dampers are proposed as control devices, a LQG-clipped-optimal control algorithm is employed. An active control strategy, shown in previous researches to perform well at controlling the benchmark bridge when uniform earthquake motion was assumed, is also used in this study to control this benchmark bridge with consideration of multiple-support excitations. The performance of active control system is compared to that of the presented semi-active control strategy. Because the MR fluid damper is a controllable energy- dissipation device that cannot add mechanical energy to the structural system, the proposed control strategy is fail-safe in that bounded-input, bounded-output stability of the controlled structure is guaranteed. The numerical results demonstrated that the performance of the presented control design is nearly the same as that of the active control system; and that the MR dampers can effectively be used to control seismically excited cable-stayed bridges with multiple-support excitations.
20. SuperTRI: A new approach based on branch support analyses of multiple independent data sets for assessing reliability of phylogenetic inferences.
Ropiquet, Anne; Li, Blaise; Hassanin, Alexandre
2009-09-01
Supermatrix and supertree are two methods for constructing a phylogenetic tree by using multiple data sets. However, these methods are not a panacea, as conflicting signals between data sets can lead to misinterpret the evolutionary history of taxa. In particular, the supermatrix approach is expected to be misleading if the species-tree signal is not dominant after the combination of the data sets. Moreover, most current supertree methods suffer from two limitations: (i) they ignore or misinterpret secondary (non-dominant) phylogenetic signals of the different data sets; and (ii) the logical basis of node robustness measures is unclear. To overcome these limitations, we propose a new approach, called SuperTRI, which is based on the branch support analyses of the independent data sets, and where the reliability of the nodes is assessed using three measures: the supertree Bootstrap percentage and two other values calculated from the separate analyses: the mean branch support (mean Bootstrap percentage or mean posterior probability) and the reproducibility index. The SuperTRI approach is tested on a data matrix including seven genes for 82 taxa of the family Bovidae (Mammalia, Ruminantia), and the results are compared to those found with the supermatrix approach. The phylogenetic analyses of the supermatrix and independent data sets were done using four methods of tree reconstruction: Bayesian inference, maximum likelihood, and unweighted and weighted maximum parsimony. The results indicate, firstly, that the SuperTRI approach shows less sensitivity to the four phylogenetic methods, secondly, that it is more accurate to interpret the relationships among taxa, and thirdly, that interesting conclusions on introgression and radiation can be drawn from the comparisons between SuperTRI and supermatrix analyses.
1. MO-C-17A-06: Online Adaptive Re-Planning to Account for Independent Motions Between Multiple Targets During Radiotherapy of Lung Cancer
Liu, F; Tai, A; Ahunbay, E; Gore, E; Johnstone, C; Li, X
2014-01-01
Purpose: To quantify interfractional independent motions between multiple targets in radiotherapy (RT) of lung cancer, and to study the dosimetric benefits of an online adaptive replanning method to account for these variations. Methods: Ninety five diagnostic-quality daily CTs acquired for 9 lung cancer patients treated with IGRT using an in-room CT (CTVision, Siemens) were analyzed. On each daily CT set, contours of the targets (GTV, CTV, or involved nodes) and organs at risk were generated by populating the planning contours using an auto-segmentation tool (ABAS, Elekta) with manual editing. For each patient, an IMRT plan was generated based on the planning CT with a prescription dose of 60 Gy in 2Gy fractions. Three plans were generated and compared for each daily CT set: an IGRT (repositioning) plan by copying the original plan with the required shifts, an online adaptive plan by rapidly modifying the aperture shapes and segment weights of the original plan to conform to the daily anatomy, and a new fully re-optimized plan based on the daily CT using a planning system (Panther, Prowess). Results: The daily deviations of the distance between centers of masses of the targets from the plans varied daily from -10 to 8 mm with an average −0.9±4.1 mm (one standard deviation). The average CTV V100 are 99.0±0.7%, 97.9±2.8%, 99.0±0.6%, and 99.1±0.6%, and the lung V20 Gy 928±332 cc, 944±315 cc, 917±300 cc, and 891±295 cc for the original, repositioning, adaptive, and re-optimized plans, respectively. Wilcoxon signed-rank tests show that the adaptive plans are statistically significantly better than the repositioning plans and comparable with the reoptimized plans. Conclusion: There exist unpredictable, interfractional, relative volume changes and independent motions between multiple targets during lung cancer RT which cannot be accounted for by the current IGRT repositioning but can be corrected by the online adaptive replanning method
2. MO-C-17A-06: Online Adaptive Re-Planning to Account for Independent Motions Between Multiple Targets During Radiotherapy of Lung Cancer
Liu, F; Tai, A; Ahunbay, E; Gore, E; Johnstone, C; Li, X [Medical College of Wisconsin, Milwaukee, WI (United States)
2014-06-15
Purpose: To quantify interfractional independent motions between multiple targets in radiotherapy (RT) of lung cancer, and to study the dosimetric benefits of an online adaptive replanning method to account for these variations. Methods: Ninety five diagnostic-quality daily CTs acquired for 9 lung cancer patients treated with IGRT using an in-room CT (CTVision, Siemens) were analyzed. On each daily CT set, contours of the targets (GTV, CTV, or involved nodes) and organs at risk were generated by populating the planning contours using an auto-segmentation tool (ABAS, Elekta) with manual editing. For each patient, an IMRT plan was generated based on the planning CT with a prescription dose of 60 Gy in 2Gy fractions. Three plans were generated and compared for each daily CT set: an IGRT (repositioning) plan by copying the original plan with the required shifts, an online adaptive plan by rapidly modifying the aperture shapes and segment weights of the original plan to conform to the daily anatomy, and a new fully re-optimized plan based on the daily CT using a planning system (Panther, Prowess). Results: The daily deviations of the distance between centers of masses of the targets from the plans varied daily from -10 to 8 mm with an average −0.9±4.1 mm (one standard deviation). The average CTV V100 are 99.0±0.7%, 97.9±2.8%, 99.0±0.6%, and 99.1±0.6%, and the lung V20 Gy 928±332 cc, 944±315 cc, 917±300 cc, and 891±295 cc for the original, repositioning, adaptive, and re-optimized plans, respectively. Wilcoxon signed-rank tests show that the adaptive plans are statistically significantly better than the repositioning plans and comparable with the reoptimized plans. Conclusion: There exist unpredictable, interfractional, relative volume changes and independent motions between multiple targets during lung cancer RT which cannot be accounted for by the current IGRT repositioning but can be corrected by the online adaptive replanning method.
3. Model-independent nonlinear control algorithm with application to a liquid bridge experiment
Petrov, V.; Haaning, A.; Muehlner, K.A.; Van Hook, S.J.; Swinney, H.L.
1998-01-01
We present a control method for high-dimensional nonlinear dynamical systems that can target remote unstable states without a priori knowledge of the underlying dynamical equations. The algorithm constructs a high-dimensional look-up table based on the system's responses to a sequence of random perturbations. The method is demonstrated by stabilizing unstable flow of a liquid bridge surface-tension-driven convection experiment that models the float zone refining process. Control of the dynamics is achieved by heating or cooling two thermoelectric Peltier devices placed in the vicinity of the liquid bridge surface. The algorithm routines along with several example programs written in the MATLAB language can be found at ftp://ftp.mathworks.com/pub/contrib/v5/control/nlcontrol. copyright 1998 The American Physical Society
4. Neurophysiology of spontaneous facial expressions: I. Motor control of the upper and lower face is behaviorally independent in adults.
Ross, Elliott D; Gupta, Smita S; Adnan, Asif M; Holden, Thomas L; Havlicek, Joseph; Radhakrishnan, Sridhar
2016-03-01
Facial expressions are described traditionally as monolithic entities. However, humans have the capacity to produce facial blends, in which the upper and lower face simultaneously display different emotional expressions. This, in turn, has led to the Component Theory of facial expressions. Recent neuroanatomical studies in monkeys have demonstrated that there are separate cortical motor areas for controlling the upper and lower face that, presumably, also occur in humans. The lower face is represented on the posterior ventrolateral surface of the frontal lobes in the primary motor and premotor cortices and the upper face is represented on the medial surface of the posterior frontal lobes in the supplementary motor and anterior cingulate cortices. Our laboratory has been engaged in a series of studies exploring the perception and production of facial blends. Using high-speed videography, we began measuring the temporal aspects of facial expressions to develop a more complete understanding of the neurophysiology underlying facial expressions and facial blends. The goal of the research presented here was to determine if spontaneous facial expressions in adults are predominantly monolithic or exhibit independent motor control of the upper and lower face. We found that spontaneous facial expressions are very complex and that the motor control of the upper and lower face is overwhelmingly independent, thus robustly supporting the Component Theory of facial expressions. Seemingly monolithic expressions, be they full facial or facial blends, are most likely the result of a timing coincident rather than a synchronous coordination between the ventrolateral and medial cortical motor areas responsible for controlling the lower and upper face, respectively. In addition, we found evidence that the right and left face may also exhibit independent motor control, thus supporting the concept that spontaneous facial expressions are organized predominantly across the horizontal facial
5. Independent control of joint stiffness in the framework of the equilibrium-point hypothesis.
Latash, M L
1992-01-01
In the framework of the equilibrium-point hypothesis, virtual trajectories and joint stiffness patterns have been reconstructed during two motor tasks practiced against a constant bias torque. One task required a voluntary increase in joint stiffness while preserving the original joint position. The other task involved fast elbow flexions over 36 degrees. Joint stiffness gradually subsided after the termination of fast movements. In both tasks, the external torque could slowly and unexpectedly change. The subjects were required not to change their motor commands if the torque changed, i.e. "to do the same no matter what the motor did". In both tasks, changes in joint stiffness were accompanied by unchanged virtual trajectories that were also independent of the absolute value of the bias torque. By contrast, the intercept of the joint compliant characteristic with the angle axis, r(t)-function, has demonstrated a clear dependence upon both the level of coactivation and external load. We assume that a template virtual trajectory is generated at a certain level of the motor hierarchy and is later scaled taking into account some commonly changing dynamic factors of the movement execution, for example, external load. The scaling leads to the generation of commands to the segmental structures that can be expressed, according to the equilibrium-point hypothesis, as changes in the thresholds of the tonic stretch reflex for corresponding muscles.
6. Action Control: Independent Effects of Memory and Monocular Viewing on Reaching Accuracy
Westwood, D.A.; Robertson, C.; Heath, M.
2005-01-01
Evidence suggests that perceptual networks in the ventral visual pathway are necessary for action control when targets are viewed with only one eye, or when the target must be stored in memory. We tested whether memory-linked (i.e., open-loop versus memory-guided actions) and monocular-linked effects (i.e., binocular versus monocular actions) on…
7. Sequence-independent control of peptide conformation in liposomal vaccines for targeting protein misfolding diseases
Hickman, D.T.; Nand, D.; Baldus, M.; Muhs, A.
2011-01-01
Synthetic peptide immunogens which mimic the conformation of a target epitope of pathological relevance offer the possibility to precisely control the immune response specificity. Here, we performed conformational analyses using a panel of peptides in order to investigate the key parameters
8. Optimal control of ODE systems involving a rate independent variational inequality
Brokate, M.; Krejčí, Pavel
2013-01-01
Roč. 18, č. 2 (2013), s. 331-348 ISSN 1531-3492 R&D Projects: GA ČR GAP201/10/2315 Institutional support: RVO:67985840 Keywords : evolution variational inequalities * hysteresis * optimal control Subject RIV: BA - General Mathematics Impact factor: 0.628, year: 2013 http://www.aimsciences.org/journals/displayArticlesnew.jsp?paperID=7971
9. Single motor–variable stiffness actuator using bistable switching mechanisms for independent motion and stiffness control
Groothuis, Stefan; Carloni, Raffaella; Stramigioli, Stefano
This paper presents a proof of concept of a variable stiffness actuator (VSA) that uses only one (high power) input motor. In general, VSAs use two (high power) motors to be able to control both the output position and the output stiffness, which possibly results in a heavy, and bulky system. In
10. The Distressed (Type D) Personality Is Independently Associated With Tinnitus : A Case-Control Study
Bartels, Hilke; Middel, Berrie; Pedersen, Susanne S.; Staal, Michiel J.; Albers, Frans W. J.
2010-01-01
Background: Tinnitus is a common and disturbing condition, reported by 10% to 20% of the general population. Objective: The authors sought to determine personality characteristics associated with tinnitus patients versus a control group of ear-nose-throat (ENT) patients without tinnitus. Method:
11. A New Attribute Control Chart using Multiple Dependent State Repetitive Sampling
Aldosari, Mansour Sattam; Aslam, Muhammad; Jun, Chi-Hyuck
2017-01-01
In this manuscript, a new attribute control chart using multiple dependent state repetitive sampling is designed. The operational procedure and structure of the proposed control chart is given. The required measures to determine the average run length (ARL) for in-control and out-of-control processes are given. Tables of ARLs are reported for various control chart parameters. The proposed control chart is more sensitive in detecting a small shift in the process as compared to the existing attribute control charts. The simulation study shows the efficiency of the proposed chart over the existing charts. An example is given for the illustration purpose.
12. A New Attribute Control Chart using Multiple Dependent State Repetitive Sampling
Aldosari, Mansour Sattam
2017-03-25
In this manuscript, a new attribute control chart using multiple dependent state repetitive sampling is designed. The operational procedure and structure of the proposed control chart is given. The required measures to determine the average run length (ARL) for in-control and out-of-control processes are given. Tables of ARLs are reported for various control chart parameters. The proposed control chart is more sensitive in detecting a small shift in the process as compared to the existing attribute control charts. The simulation study shows the efficiency of the proposed chart over the existing charts. An example is given for the illustration purpose.
13. Existence of multiple receptors in single neurons: responses of single bullfrog olfactory neurons to many cAMP-dependent and independent odorants.
Kashiwayanagi, M; Shimano, K; Kurihara, K
1996-11-04
The responses of single bullfrog olfactory neurons to various odorants were measured with the whole-cell patch clamp which offers direct information on cellular events and with the ciliary recording technique to obtain stable quantitative data from many neurons. A large portion of single olfactory neurons (about 64% and 79% in the whole-cell recording and in the ciliary recording, respectively) responded to many odorants with quite diverse molecular structures, including both odorants previously indicated to be cAMP-dependent (increasing) and independent odorants. One odorant elicited a response in many cells; e.g. hedione and citralva elicited the response in 100% and 92% of total neurons examined with the ciliary recording technique. To confirm that a single neuron carries different receptors or transduction pathways, the cross-adaptation technique was applied to single neurons. Application of hedione to a single neuron after desensitization of the current in response to lyral or citralva induced an inward current with a similar magnitude to that applied alone. It was suggested that most single olfactory neurons carry multiple receptors and at least dual transduction pathways.
14. Evaluation of an every-other-day palonosetron schedule to control emesis in multiple-day high-dose chemotherapy.
Mirabile, Aurora; Celio, Luigi; Magni, Michele; Bonizzoni, Erminio; Gianni, Alessandro Massimo; Di Nicola, Massimo
2014-12-01
Efficacy of intermittent palonosetron dosing in patients undergoing multiple-day, high-dose chemotherapy (HDC) was investigated. Fifty-eight patients received palonosetron (0.25 mg intravenous [iv.]) every other day plus daily dexamethasone (8 mg iv. twice daily) dosing. The primary end point was complete control (CC; no emesis, no rescue anti-emetics, and no more than mild nausea) in the overall acute-period (until 24 h after chemotherapy completion). Acute-period CC occurred in 81% and 50% of patients receiving palonosetron and ondansetron (historical control cohort), respectively. Palonosetron (odds ratio [OR]: 4.37; p = 0.001) and a longer duration of HDC regimen (OR: 3.47; p = 0.011) independently predicted a better anti-emetic outcome. Palonosetron every other day plus daily dexamethasone is an effective anti-emetic coverage in patients undergoing HDC.
15. Design of Parameter Independent, High Performance Sensorless Controllers for Permanent Magnet Synchronous Machines
Xie, Ge
. The transient fluctuation of the estimated rotor position error is around 20 degrees with a step load torque change from 0% to 100% of the rated torque. The position error in steady state is within ±2 electrical degrees for the best case. The proposed method may also be used for e.g. online machine parameter......The Permanent Magnet Synchronous Machine (PMSM) has become an attractive candidate for various industrial applications due to its high efficiency and torque density. In the PMSM drive system, simple and robust control methods play an important role in achieving satisfactory drive performances....... For reducing the cost and increasing the reliability of the drive system, eliminating the mechanical sensor brings a lot advantages to the PMSM drive system. Therefore, sensorless control was developed and has been increasingly used in different PMSM drive systems in the last 20 years. However, machine...
16. Independent walking as a major skill for the development of anticipatory postural control: evidence from adjustments to predictable perturbations.
Fabien Cignetti
Full Text Available Although there is suggestive evidence that a link exists between independent walking and the ability to establish anticipatory strategy to stabilize posture, the extent to which this skill facilitates the development of anticipatory postural control remains largely unknown. Here, we examined the role of independent walking on the infants' ability to anticipate predictable external perturbations. Non-walking infants, walking infants and adults were sitting on a platform that produced continuous rotation in the frontal plane. Surface electromyography (EMG of neck and lower back muscles and the positions of markers located on the platform, the upper body and the head were recorded. Results from cross-correlation analysis between rectified and filtered EMGs and platform movement indicated that although muscle activation already occurred before platform movement in non-walking infants, only walking infants demonstrated an adult-like ability for anticipation. Moreover, results from further cross-correlation analysis between segmental angular displacement and platform movement together with measures of balance control at the end-points of rotation of the platform evidenced two sorts of behaviour. The adults behaved as a non-rigid non-inverted pendulum, rather stabilizing head in space, while both the walking and non-walking infants followed the platform, behaving as a rigid inverted pendulum. These results suggest that the acquisition of independent walking plays a role in the development of anticipatory postural control, likely improving the internal model for the sensorimotor control of posture. However, despite such improvement, integrating the dynamics of an external object, here the platform, within the model to maintain balance still remains challenging in infants.
17. Multiple single-board-computer system for the KEK positron generator control
Nakahara, Kazuo; Abe, Isamu; Enomoto, Atsushi; Otake, Yuji; Urano, Takao
1986-01-01
The KEK positron generator is controlled by means of a distributed microprocessor network. The control system is composed of three kinds of equipment: device controllers for the linac equipment, operation management stations and a communication network. Individual linac equipment has its own microprocessor-based controller. A multiple single board computer (SBC) system is used for communication control and for equipment surveillance; it has a database containing communication and linac equipment status information. The linac operation management that should be the most soft part in the control system, is separated from the multiple SBC system and is carried out by work-stations. The principle that every processor executes only one task is maintained throughout the control system. This made the software architecture very simple. (orig.)
18. Association mapping in sunflower (Helianthus annuus L.) reveals independent control of apical vs. basal branching.
Nambeesan, Savithri U; Mandel, Jennifer R; Bowers, John E; Marek, Laura F; Ebert, Daniel; Corbi, Jonathan; Rieseberg, Loren H; Knapp, Steven J; Burke, John M
2015-03-11
Shoot branching is an important determinant of plant architecture and influences various aspects of growth and development. Selection on branching has also played an important role in the domestication of crop plants, including sunflower (Helianthus annuus L.). Here, we describe an investigation of the genetic basis of variation in branching in sunflower via association mapping in a diverse collection of cultivated sunflower lines. Detailed phenotypic analyses revealed extensive variation in the extent and type of branching within the focal population. After correcting for population structure and kinship, association analyses were performed using a genome-wide collection of SNPs to identify genomic regions that influence a variety of branching-related traits. This work resulted in the identification of multiple previously unidentified genomic regions that contribute to variation in branching. Genomic regions that were associated with apical and mid-apical branching were generally distinct from those associated with basal and mid-basal branching. Homologs of known branching genes from other study systems (i.e., Arabidopsis, rice, pea, and petunia) were also identified from the draft assembly of the sunflower genome and their map positions were compared to those of associations identified herein. Numerous candidate branching genes were found to map in close proximity to significant branching associations. In sunflower, variation in branching is genetically complex and overall branching patterns (i.e., apical vs. basal) were found to be influenced by distinct genomic regions. Moreover, numerous candidate branching genes mapped in close proximity to significant branching associations. Although the sunflower genome exhibits localized islands of elevated linkage disequilibrium (LD), these non-random associations are known to decay rapidly elsewhere. The subset of candidate genes that co-localized with significant associations in regions of low LD represents the most
19. Multiple-state based power control for multi-radio multi-channel wireless mesh networks
Olwal, TO
2009-01-01
Full Text Available Multi-Radio Multi-Channel (MRMC) systems are key to power control problems in wireless mesh networks (WMNs). In this paper, we present asynchronous multiple-state based power control for MRMC WMNs. First, WMN is represented as a set of disjoint...
20. A simple optical fibre-linked remote control system for multiple devices
We report on the development of a simple control system which can handle multiple devices through an optical fibre data link. The devices are controlled using a set of DACs through serial data communication via a serial port of a PC. Serial data from the PC get converted to parallel mode using a homemade “serial in ...
1. EVALUATION OF A CONCEPTUAL VEHICLE STEERING SYSTEM FOR INDEPENDENT WHEEL CONTROL
Ryszard BUCHALIK
2017-03-01
Full Text Available This paper presents a brief description of an unconventional steering system involving electronic stability control and its influence on vehicle motion. The proposed configuration enables individual changes in steering angle for each single wheel, in contrast to the mechanical linkage solution. An analysis of vehicle behaviour during emergency braking on a heterogeneous surface is conducted, especially with regard to the undesirable rotation of the vehicle body. The benefits of using this active steering system, implemented in the steer-by-wire mode, are characterized, while the problems for further consideration and the potential benefits of such a solution are described.
2. Real-time control of a microfluidic channel for size-independent deformability cytometry
Guan, Guofeng; Chen, Peter C Y; Ong, Chong Jin; Peng, Weng Kung; Bhagat, Ali Asgar; Han, Jongyoon
2012-01-01
Mechanical properties of cells can be correlated with various cell states and are now considered as an important class of biophysical markers. Effectiveness of existing high-throughput microfluidic techniques for investigating cell mechanical properties is adversely affected by cell-size variation in a given cell population. In this work, we introduce a new microfluidic system with real-time feedback control to evaluate single-cell deformability while minimizing cell-size dependence of the measurement. Using breast cancer cells (MCF-7), we demonstrate the potential of this system for stiffness profiling of cells in complex, diverse cell populations. (paper)
3. Second-Order Controllability of Multi-Agent Systems with Multiple Leaders
Liu Bo; Han Xiao; Shi Yun-Tao; Su Hou-Sheng
2016-01-01
This paper proposes a new second-order continuous-time multi-agent model and analyzes the controllability of second-order multi-agent system with multiple leaders based on the asymmetric topology. This paper considers the more general case: velocity coupling topology is different from location coupling topology. Some sufficient and necessary conditions are presented for the controllability of the system with multiple leaders. In addition, the paper studies the controllability of the system with velocity damping gain. Simulation results are given to illustrate the correctness of theoretical results. (paper)
4. HLA-A*7401-mediated control of HIV viremia is independent of its linkage disequilibrium with HLA-B*5703
Matthews, Philippa C; Adland, Emily; Listgarten, Jennifer
2011-01-01
-clade-infected subjects. We present evidence that HLA-A*7401 operates an effect that is independent of HLA-B*5703, with which it is in linkage disequilibrium in some populations, to mediate lowered viremia. We describe a novel statistical approach to detecting additive effects between class I alleles in control of HIV-1...... epitopes appear immunodominant. We identify eight novel putative HLA-A*7401-restricted epitopes, of which three have been defined to the optimal epitope. In common with HLA-B alleles linked with slow progression, viremic control through an HLA-A*7401-restricted response appears to be associated...... with the selection of escape mutants within Gag epitopes that reduce viral replicative capacity. These studies highlight the potentially important contribution of an HLA-A allele to immune control of HIV infection, which may have been concealed by a stronger effect mediated by an HLA-B allele with which...
5. Perfect controlled joint remote state preparation independent of entanglement degree of the quantum channel
An, Nguyen Ba; Bich, Cao Thi
2014-01-01
We construct a quantum circuit to produce a task-oriented partially entangled state and use it as the quantum channel for controlled joint remote state preparation. Unlike most previous works, where the parameters of the quantum channel are given to the receiver who can accomplish the task only probabilistically by consuming auxiliary resource, operation and measurement, here we give them to the supervisor. Thanks to the knowledge of the task-oriented quantum channel parameters, the supervisor can carry out proper complete projective measurement, which, combined with the feed-forward technique adapted by the preparers, not only much economizes (simplifies) the receiver's resource (operation) but also yields unit total success probability. Notably, such apparent perfection does not depend on the entanglement degree of the shared quantum channel. Our protocol is within the reach of current quantum technologies. - Highlights: • Controlled joint remote state preparation is considered. • Quantum circuit is proposed to produce task-oriented partially entangled channel. • The quantum channel parameter is given to the supervisor (not to the receiver). • Unit success probability without additional resource/operations/measurement. • Perfection is achieved regardless of the shared entanglement degree
6. Independent evaluation of a canine Echinococcosis Control Programme in Hobukesar County, Xinjiang, China.
van Kesteren, Freya; Qi, Xinwei; Tao, Jiang; Feng, Xiaohui; Mastin, Alexander; Craig, Philip S; Vuitton, Dominique A; Duan, Xinyu; Chu, Xiangdong; Zhu, Jinlong; Wen, Hao
2015-05-01
The Xinjiang Uyghur Autonomous Region in northwest China is one of the world's most important foci for cystic echinococcosis. Domestic dogs are the main source for human infection, and previous studies in Xinjiang have found a canine Echinococcus spp. coproELISA prevalence of between 36% and 41%. In 2010 the Chinese National Echinococcosis Control Programme was implemented in Xinjiang, and includes regular dosing of domestic dogs with praziquantel. Six communities in Hobukesar County, northwest Xinjiang were assessed in relation to the impact of this control programme through dog necropsies, dog Echinococcus spp. coproantigen surveys based on Lot Quality Assurance Sampling (LQAS) and dog owner questionnaires. We found that 42.1% of necropsied dogs were infected with Echinococcus granulosus, and coproELISA prevalences were between 15% and 70% in the communities. Although approximately half of all dog owners reported dosing their dogs within the 12 months prior to sampling, coproELISA prevalence remained high. Regular praziquantel dosing of owned dogs in remote and semi-nomadic communities such as those in Hobukesar County is logistically very difficult and additional measures should be considered to reduce canine echinococcosis. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.
7. An empirical model for independent control of variable speed refrigeration system
Li Hua; Jeong, Seok-Kwon; Yoon, Jung-In; You, Sam-Sang
2008-01-01
This paper deals with an empirical dynamic model for decoupling control of the variable speed refrigeration system (VSRS). To cope with inherent complexity and nonlinearity in system dynamics, the model parameters are first obtained based on experimental data. In the study, the dynamic characteristics of indoor temperature and superheat are assumed to be first-order model with time delay. While the compressor frequency and opening angle of electronic expansion valve are varying, the indoor temperature and the superheat exhibit interfering characteristics each other in the VSRS. Thus, each decoupling model has been proposed to eliminate such interference. Finally, the experiment and simulation results indicate that the proposed model offers more tractable means for describing the actual VSRS comparing to other models currently available
8. Advanced topics in control and estimation of state-multiplicative noisy systems
Gershon, Eli
2013-01-01
Advanced Topics in Control and Estimation of State-Multiplicative Noisy Systems begins with an introduction and extensive literature survey. The text proceeds to cover solutions of measurement-feedback control and state problems and the formulation of the Bounded Real Lemma for both continuous- and discrete-time systems. The continuous-time reduced-order and stochastic-tracking control problems for delayed systems are then treated. Ideas of nonlinear stability are introduced for infinite-horizon systems, again, in both the continuous- and discrete-time cases. The reader is introduced to six practical examples of noisy state-multiplicative control and filtering associated with various fields of control engineering. The book is rounded out by a three-part appendix containing stochastic tools necessary for a proper appreciation of the text: a basic introduction to nonlinear stochastic differential equations and aspects of switched systems and peak to peak optimal control and filtering. Advanced Topics in Contr...
9. Independent sailing with high tetraplegia using sip and puff controls: integration into a community sailing center.
Rojhani, Solomon; Stiens, Steven A; Recio, Albert C
2017-07-01
We are continually rediscovering how adapted recreational activity complements the rehabilitation process, enriches patients' lives and positively impacts outcome measures. Although sports for people with spinal cord injuries (SCI) has achieved spectacular visibility, participation by high cervical injuries is often restricted due to poor accessibility, safety concerns, lack of adaptability, and high costs of technology. We endeavor to demonstrate the mechanisms, adaptability, accessibility, and benefits the sport of sailing creates in the rehabilitative process. Our sailor is a 27-year-old man with a history of traumatic SCI resulting in C4 complete tetraplegia. The participant completed an adapted introductory sailing course, and instruction on the sip-and-puff sail and tiller control mechanism. With practice, he navigated an on-water course in moderate winds of 5 to 15 knots. Despite trends toward shorter rehabilitation stays, aggressive transdisciplinary collaboration with recreation therapy can provide community and natural environment experiences while inpatient and continuing post discharge. Such peak physical and psychological experiences provide a positive perspective for the future that can be shared on the inpatient unit, with families and support systems like sailing clubs in the community. Rehabilitation theory directs a team process to achieve patient self-awareness and initiate self-actualization in spite of disablement. Utilization of local community sailing centers that have provided accessible assisted options provides person-centered self-realization of goals as assisted by family and natural supports. Such successful patients become native guides for others seeking the same experience.
10. Common and Low Frequency Variants in MERTK Are Independently Associated with Multiple Sclerosis Susceptibility with Discordant Association Dependent upon HLA-DRB1*15:01 Status.
Michele D Binder
2016-03-01
Full Text Available Multiple Sclerosis (MS is a chronic inflammatory demyelinating disease of the central nervous system. The risk of developing MS is strongly influenced by genetic predisposition, and over 100 loci have been established as associated with susceptibility. However, the biologically relevant variants underlying disease risk have not been defined for the vast majority of these loci, limiting the power of these genetic studies to define new avenues of research for the development of MS therapeutics. It is therefore crucial that candidate MS susceptibility loci are carefully investigated to identify the biological mechanism linking genetic polymorphism at a given gene to the increased chance of developing MS. MERTK has been established as an MS susceptibility gene and is part of a family of receptor tyrosine kinases known to be involved in the pathogenesis of demyelinating disease. In this study we have refined the association of MERTK with MS risk to independent signals from both common and low frequency variants. One of the associated variants was also found to be linked with increased expression of MERTK in monocytes and higher expression of MERTK was associated with either increased or decreased risk of developing MS, dependent upon HLA-DRB1*15:01 status. This discordant association potentially extended beyond MS susceptibility to alterations in disease course in established MS. This study provides clear evidence that distinct polymorphisms within MERTK are associated with MS susceptibility, one of which has the potential to alter MERTK transcription, which in turn can alter both susceptibility and disease course in MS patients.
11. Independent Directors
Ringe, Wolf-Georg
2013-01-01
This paper re-evaluates the corporate governance concept of ‘board independence’ against the disappointing experiences during the 2007-08 financial crisis. Independent or outside directors had long been seen as an essential tool to improve the monitoring role of the board. Yet the crisis revealed...... that they did not prevent firms' excessive risk taking; further, these directors sometimes showed serious deficits in understanding the business they were supposed to control, and remained passive in addressing structural problems. A closer look reveals that under the surface of seemingly unanimous consensus...
12. Serum uric acid level is an independent risk factor for presence of calcium in coronary arteries: an observational case-controlled study.
Atar, Aslı Inci; Yılmaz, Omer Cağlar; Akın, Kayıhan; Selçoki, Yusuf; Er, Okan; Eryonucu, Beyhan
2013-03-01
A link between uric acid levels and cardiovascular diseases has been previously reported. Coronary artery calcium score (CACS) is a marker of atherosclerotic disease and a predictor of cardiovascular events. We sought to determine if serum uric acid level is an independent risk factor for the presence of calcium in coronary arteries. Four hundred and forty-two patients who were evaluated in the cardiology outpatient clinic for suspected coronary heart disease with a low-moderate risk for coronary artery disease were included in this observational case-controlled study. Serum uric acid levels were measured with colorimetric methods. CACS were performed using a 64-slice CT scanner. Patients were divided to 3 groups according to their CACS value (Group 1: CACS=0, Group 2: CACS 1-100, Group 3: CACS>100). The demographical characteristics and laboratory findings of 3 groups were similar, except age, fasting glucose levels and serum uric acid levels. Serum uric acid levels were found to increase significantly with increasing CACS (p=0.001). Patients were grouped according to presence CAC (CACS=0 and CACS≥1) and in the multiple regression analysis, age (OR, 1.11, 95% CI, 1.07-1.16), smoking (OR, 3.83, 95% CI, 2.06-7.09), serum uric acid levels (OR, 1.26, 95% CI, 1.04-1.54) and average 10-year total risk of Framingham risk score (OR, 1.13, 95% CI, 1.04-1.09) appeared as independent factors predictive of presence of CAC (p<0.05). Serum uric acid level is an independent risk factor for presence of coronary calcium. Moreover, increasing levels of serum uric acid are associated with increasing CACS.
13. Experiences in simulating and testing coordinated voltage control provided by multiple wind power plants
Arlaban, T.; Alonso, O.; Ortiz, D. [Acciona Windpower S.A. (Spain); Peiro, J.; Rivas, R. [Red Electrica de Espana SAU (Spain); Quinonez-Varela, G.; Lorenzo, P. [Acciona Energia S.A. (Spain)
2011-07-01
This document presents some field tests performed in a transmission system node in order to check the adequacy of voltage control performance by multiple wind power plants, with an overall capacity of 395 MW. It briefly explains the Spanish TSO motivation towards new voltage control requirements and the necessity of performing such tests in order to set the most convenient voltage control parameters and to verify the stable operation. It presents how different the voltage control capability between modern wind turbines (DFIG) and older ones (SCIG) specifically retrofitted for voltage control is. (orig.)
14. A Memory/Immunology-Based Control Approach with Applications to Multiple Spacecraft Formation Flying
Liguo Weng
2013-01-01
Full Text Available This paper addresses the problem of formation control for multiple spacecrafts in Planetary Orbital Environment (POE. Due to the presence of diverse interferences and uncertainties in the outer space, such as the changing spacecraft mass, unavailable space parameters, and varying gravity forces, traditional control methods encounter great difficulties in this area. A new control approach inspired by human memory and immune system is proposed, and this approach is shown to be capable of learning from past control experience and current behavior to improve its performance. It demands much less system dynamic information as compared with traditional controls. Both theoretic analysis and computer simulation verify its effectiveness.
15. A feedback control model for network flow with multiple pure time delays
Press, J.
1972-01-01
A control model describing a network flow hindered by multiple pure time (or transport) delays is formulated. Feedbacks connect each desired output with a single control sector situated at the origin. The dynamic formulation invokes the use of differential difference equations. This causes the characteristic equation of the model to consist of transcendental functions instead of a common algebraic polynomial. A general graphical criterion is developed to evaluate the stability of such a problem. A digital computer simulation confirms the validity of such criterion. An optimal decision making process with multiple delays is presented.
16. Exponential Antisynchronization Control of Stochastic Memristive Neural Networks with Mixed Time-Varying Delays Based on Novel Delay-Dependent or Delay-Independent Adaptive Controller
Minghui Yu
2017-01-01
Full Text Available The global exponential antisynchronization in mean square of memristive neural networks with stochastic perturbation and mixed time-varying delays is studied in this paper. Then, two kinds of novel delay-dependent and delay-independent adaptive controllers are designed. With the ability of adapting to environment changes, the proposed controllers can modify their behaviors to achieve the best performance. In particular, on the basis of the differential inclusions theory, inequality theory, and stochastic analysis techniques, several sufficient conditions are obtained to guarantee the exponential antisynchronization between the drive system and response system. Furthermore, two numerical simulation examples are provided to the validity of the derived criteria.
17. Control Strategies for Islanded Microgrid using Enhanced Hierarchical Control Structure with Multiple Current-Loop Damping Schemes
Han, Yang; Shen, Pan; Zhao, Xin
2017-01-01
In this paper, the modeling, controller design, and stability analysis of the islanded microgrid (MG) using enhanced hierarchical control structure with multiple current loop damping schemes is proposed. The islanded MG is consisted of the parallel-connected voltage source inverters using LCL...... output filters, and the proposed control structure includes: the primary control with additional phase-shift loop, the secondary control for voltage amplitude and frequency restoration, the virtual impedance loops which contains virtual positive- and negative-sequence impedance loops at fundamental...... frequency, and virtual variable harmonic impedance loop at harmonic frequencies, and the inner voltage and current loop controllers. A small-signal model for the primary and secondary controls with additional phase-shift loop is presented, which shows an over-damped feature from eigenvalue analysis...
18. Controlled multiple neutral planes by low elastic modulus adhesive for flexible organic photovoltaics.
Kim, Wansun; Lee, Inhwa; Yoon Kim, Dong; Yu, Youn-Yeol; Jung, Hae-Yoon; Kwon, Seyeoul; Seo Park, Weon; Kim, Taek-Soo
2017-05-12
To protect brittle layers in organic photovoltaic devices, the mechanical neutral plane strategy can be adopted through placing the brittle functional materials close to the neutral plane where stress and strain are zero during bending. However, previous research has been significantly limited in the location and number of materials to protect through using a single neutral plane. In this study, multiple neutral planes are generated using low elastic modulus adhesives and are controlled through quantitative analyses in order to protect the multiple brittle materials at various locations. Moreover, the protection of multiple brittle layers at various locations under both concave and convex bending directions is demonstrated. Multilayer structures that have soft adhesives are further analyzed using the finite element method analysis in order to propose guidelines for structural design when employing multiple neutral planes.
19. Multi-Axis Independent Electromechanical Load Control for Docking System Actuation Development and Verification Using dSPACE
Oesch, Christopher; Dick, Brandon; Rupp, Timothy
2015-01-01
The development of highly complex and advanced actuation systems to meet customer demands has accelerated as the use of real-time testing technology expands into multiple markets at Moog. Systems developed for the autonomous docking of human rated spacecraft to the International Space Station (ISS), envelope multi-operational characteristics which place unique constraints on an actuation system. Real-time testing hardware has been used as a platform for incremental testing and development for the linear actuation system which controls initial capture and docking for vehicles visiting the ISS. This presentation will outline the role of dSPACE hardware as a platform for rapid control-algorithm prototyping as well as an Electromechanical Actuator (EMA) system dynamic loading simulator, both conducted at Moog to develop the safety critical Linear Actuator System (LAS) of the NASA Docking System (NDS).
20. Managerial leadership is associated with employee stress, health, and sickness absence independently of the demand-control-support model.
Westerlund, Hugo; Nyberg, Anna; Bernin, Peggy; Hyde, Martin; Oxenstierna, Gabriel; Jäppinen, Paavo; Väänänen, Ari; Theorell, Töres
2010-01-01
Research on health effects of managerial leadership has only taken established work environment factors into account to a limited extent. We therefore investigated the associations between a measure of Attentive Managerial Leadership (AML), and perceived stress, age-relative self-rated health, and sickness absence due to overstrain/fatigue, adjusting for the dimensions of the Demand-Control-Support model. Blue- and white-collar workers from Finland, Germany and Sweden employed in a multi-national forest industry company (N=12,622). Cross-sectional data on leadership and health from a company-wide survey analysed with logistic regression in different subgroups. AML was associated with perceived stress, age-relative self-rated health, and sickness absence due to overstrain/fatigue after controlling for the Demand-Control-Support model. Lack of AML was significantly associated with a high stress level in all subgroups (OR=1.68-2.67). Associations with age-relative self-rated health and sickness absence due to overstrain/fatigue were weaker, but still significant, and in the expected direction for several of the subgroups studied, suggesting an association between lack of AML and negative health consequences. The study indicates that managerial leadership is associated with employee stress, health, and sickness absence independently of the Demand-Control-Support model and should be considered in future studies of health consequences for employees, and in work environment interventions.
1. Antibody-independent control of gamma-herpesvirus latency via B cell induction of anti-viral T cell responses.
Kelly B McClellan
2006-06-01
Full Text Available B cells can use antibody-dependent mechanisms to control latent viral infections. It is unknown whether this represents the sole function of B cells during chronic viral infection. We report here that hen egg lysozyme (HEL-specific B cells can contribute to the control of murine gamma-herpesvirus 68 (gammaHV68 latency without producing anti-viral antibody. HEL-specific B cells normalized defects in T cell numbers and proliferation observed in B cell-/- mice during the early phase of gammaHV68 latency. HEL-specific B cells also reversed defects in CD8 and CD4 T cell cytokine production observed in B cell-/- mice, generating CD8 and CD4 T cells necessary for control of latency. Furthermore, HEL-specific B cells were able to present virally encoded antigen to CD8 T cells. Therefore, B cells have antibody independent functions, including antigen presentation, that are important for control of gamma-herpesvirus latency. Exploitation of this property of B cells may allow enhanced vaccine responses to chronic virus infection.
2. Co-Design Based Lateral Motion Control of All-Wheel-Independent-Drive Electric Vehicles with Network Congestion
Wanke Cao
2017-10-01
Full Text Available All-wheel-independent-drive electric vehicles (AWID-EVs have considerable advantages in terms of energy optimization, drivability and driving safety due to the remarkable actuation flexibility of electric motors. However, in their current implementations, various real-time data in the vehicle control system are exchanged via a controller area network (CAN, which causes network congestion and network-induced delays. These problems could lead to systemic instability and make the system integration difficult. The goal of this paper is to provide a design methodology that can cope with all these challenges for the lateral motion control of AWID-EVs. Firstly, a continuous-time model of an AWID-EV is derived. Then an expression for determining upper and lower bounds on the delays caused by CAN is presented and with which a discrete-time model of the closed-loop CAN system is derived. An expression on the bandwidth utilization is introduced as well. Thirdly, a co-design based scheme combining a period-dependent linear quadratic regulator (LQR and a dynamic period scheduler is designed for the resulting model and the stability criterion is also derived. The results of simulations and hard-in-loop (HIL experiments show that the proposed methodology can effectively guarantee the stability of the vehicle lateral motion control while obviously declining the network congestion.
3. Source-dependent and source-independent controls on plutonium oxidation state and colloid associations in groundwater.
Buesseler, Ken O; Kaplan, Daniel I; Dai, Minhan; Pike, Steven
2009-03-01
Plutonium (Pu) was characterized for its isotopic composition, oxidation states, and association with colloids in groundwater samples near disposal basins in F-Area of the Savannah River Site and compared to similar samples collected six years earlier. Two sources of Pu were identified, the disposal basins, which contained a 24Pu/l39Pu isotopic signature consistent with weapons grade Pu, and 244Cm, a cocontaminant that is a progenitor radionuclide of 24Pu. 24Pu that originated primarily from 244Cm tended to be appreciably more oxidized (Pu(V/VI)), less associated with colloids (approximately 1 kDa - 0.2 microm), and more mobile than 239Pu, as suggested by our prior studies at this site. This is not evidence of isotope fractionation but rather "source-dependent" controls on 240Pu speciation which are processes that are not at equilibrium, i.e., processes that appear kinetically hindered. There were also "source-independent" controls on 239Pu speciation, which are those processes that follow thermodynamic equilibrium with their surroundings. For example, a groundwater pH increase in one well from 4.1 in 1998 to 6.1 in 2004 resulted in an order of magnitude decrease in groundwater 239Pu concentrations. Similarly, the fraction of 239Pu in the reduced Pu(III/IV) and colloidal forms increased systematically with decreases in redox condition in 2004 vs 1998. This research demonstrates the importance of source-dependent and source-independent controls on Pu speciation which would impact Pu mobility during changes in hydrological, chemical, or biological conditions on both seasonal and decadal time scales, and over short spatial scales. This implies more dynamic shifts in Pu speciation, colloids association, and transport in groundwater than commonly believed.
4. Assessment of Personality Types and Locus of Control in Multiple Sclerosis Patients
Sh. Mazaheri
2008-07-01
Full Text Available Introduction & Objective: Multiple sclerosis (MS is an autoimmune disease with unknown cause. MS is one of the disabling neurologic diseases in adult especially young range that myelin part of central nervous system (CNS is destructed. The aim of this study was assessment of types A and B personality and internal and external locus of control in multiple sclerosis (MS patients and comparison of the results with control group.Materials & Methods: In a case-control study, 30 patients with MS and 30 normal persons as control group evaluated with neurological examination, Rotter locus of control test and Friedman-Rosenman questionnaire for detection of types A and B personality. We employed to analyze the results.Results: 43 percent and 57 percent of MS patients had internal and external locus of control respectively. 63 percent and 37 percent of MS patients had type A and B personality respectively. 60 percent and 40 percent of control group had internal and external locus of control respectively. 20 percent and 80 percent of control group had type A and B personality respectively. Difference between personality type in two groups was significant (P<0.01.Conclusions: In this study, MS patients had more type A personality in comparison to control group.
5. Consensus definitions and application guidelines for control groups in cerebrospinal fluid biomarker studies in multiple sclerosis
Teunissen, Charlotte; Menge, Til; Altintas, Ayse
2013-01-01
The choice of appropriate control group(s) is critical in cerebrospinal fluid (CSF) biomarker research in multiple sclerosis (MS). There is a lack of definitions and nomenclature of different control groups and a rationalized application of different control groups. We here propose consensus......). Furthermore, we discuss the application of these control groups in specific study designs, such as for diagnostic biomarker studies, prognostic biomarker studies and therapeutic response studies. Application of these uniform definitions will lead to better comparability of biomarker studies and optimal use...
6. Robust Fault Tolerant Control for a Class of Time-Delay Systems with Multiple Disturbances
Songyin Cao
2013-01-01
Full Text Available A robust fault tolerant control (FTC approach is addressed for a class of nonlinear systems with time delay, actuator faults, and multiple disturbances. The first part of the multiple disturbances is supposed to be an uncertain modeled disturbance and the second one represents a norm-bounded variable. First, a composite observer is designed to estimate the uncertain modeled disturbance and actuator fault simultaneously. Then, an FTC strategy consisting of disturbance observer based control (DOBC, fault accommodation, and a mixed H2/H∞ controller is constructed to reconfigure the considered systems with disturbance rejection and attenuation performance. Finally, simulations for a flight control system are given to show the efficiency of the proposed approach.
7. The Controlling Nutritional Status Score Is a Significant Independent Predictor of Poor Prognosis in Patients With Malignant Pleural Mesothelioma.
Takamori, Shinkichi; Toyokawa, Gouji; Taguchi, Kenichi; Edagawa, Makoto; Shimamatsu, Shinichiro; Toyozawa, Ryo; Nosaki, Kaname; Seto, Takashi; Hirai, Fumihiko; Yamaguchi, Masafumi; Shoji, Fumihiro; Okamoto, Tatsuro; Takenoyama, Mitsuhiro; Ichinose, Yukito
2017-07-01
Malignant pleural mesothelioma (MPM) is a devastating neoplasm; however, some patients exhibit a good response to chemotherapy or multidisciplinary therapy, including surgery and chemotherapy. It is therefore important to discover the factors that can be used to select patients who will benefit from such treatment. Although the Controlling Nutritional Status (CONUT) score has been used to predict the prognosis in other types of malignancy, its utility in patients with MPM is unknown. The aim of this study was to clarify the clinical significance of the CONUT in patients with MPM. The data of 83 patients, who were treated with surgery, chemotherapy, or multidisciplinary therapy, were analyzed in the present study. A cut-off CONUT score of 2 was used to classify all of the patients into low or high CONUT groups. Fifty-two of the 83 patients were classified into the low CONUT group. A high CONUT score was significantly correlated with chemotherapy alone (P = .011). The high CONUT group had significantly poorer overall survival (OS) (P clinical stage and the CONUT score were found to be independent predictive factors for the OS: clinical stage, I/II and III/IV; P = .001 and CONUT score, ≥ 3 and ≤ 2; P = .011, respectively. The clinical stage and the CONUT score were also independent predictive factors for DFS/PFS: clinical stage, I/II and III/IV; P = .006 and CONUT score, ≥ 3 and ≤ 2; P = .013, respectively. The CONUT score was an independent predictor of a poor prognosis in the patients with MPM. This score provides useful information for selecting patients who will benefit from the treatment. Copyright © 2017 Elsevier Inc. All rights reserved.
8. Loss of heterozygosity on chromosome 11q13 in two families with acromegaly/gigantism is independent of mutations of the multiple endocrine neoplasia type I gene.
Gadelha, M R; Prezant, T R; Une, K N; Glick, R P; Moskal, S F; Vaisman, M; Melmed, S; Kineman, R D; Frohman, L A
1999-01-01
Familial acromegaly/gigantism occurring in the absence of multiple endocrine neoplasia type I (MEN-1) or the Carney complex has been reported in 18 families since the biochemical diagnosis of GH excess became available, and the genetic defect is unknown. In the present study we examined 2 unrelated families with isolated acromegaly/gigantism. In family A, 3 of 4 siblings were affected, with ages at diagnosis of 19, 21, and 23 yr. In family B, 5 of 13 siblings exhibited the phenotype and were diagnosed at 13, 15, 17, 17, and 24 yr of age. All 8 affected patients had elevated basal GH levels associated with high insulin-like growth factor I levels and/or nonsuppressible serum GH levels during an oral glucose tolerance test. GHRH levels were normal in affected members of family A. An invasive macroadenoma was found in 6 subjects, and a microadenoma was found in 1 subject from family B. The sequence of the GHRH receptor complementary DNA in 1 tumor from family A was normal. There was no history of consanguinity in either family, and the past medical history and laboratory results excluded MEN-1 and the Carney complex in all affected and unaffected screened subjects. Five of 8 subjects have undergone pituitary surgery to date, and paraffin-embedded pituitary blocks were available for analysis. Loss of heterozygosity on chromosome 11q13 was studied by comparing microsatellite polymorphisms of leukocyte and tumor DNA using PYGM (centromeric) and D11S527 (telomeric), markers closely linked to the MEN-1 tumor suppressor gene. All tumors exhibited a loss of heterozygosity at both markers. Sequencing of the MEN-1 gene revealed no germline mutations in either family, nor was a somatic mutation found in tumor DNA from one subject in family A. The integrity of the MEN-1 gene in this subject was further supported by demonstration of the presence of MEN-1 messenger ribonucleic acid, as assessed by RT-PCR. These data indicate that loss of heterozygosity in these affected family
9. Smart Control of Multiple Evaporator Systems with Wireless Sensor and Actuator Networks
Apolinar González-Potes
2016-02-01
Full Text Available This paper describes the complete integration of a fuzzy control of multiple evaporator systems with the IEEE 802.15.4 standard, in which we study several important aspects for this kind of system, like a detailed analysis of the end-to-end real-time flows over wireless sensor and actuator networks (WSAN, a real-time kernel with an earliest deadline first (EDF scheduler, periodic and aperiodic tasking models for the nodes, lightweight and flexible compensation-based control algorithms for WSAN that exhibit packet dropouts, an event-triggered sampling scheme and design methodologies. We address the control problem of the multi-evaporators with the presence of uncertainties, which was tackled through a wireless fuzzy control approach, showing the advantages of this concept where it can easily perform the optimization for a set of multiple evaporators controlled by the same smart controller, which should have an intelligent and flexible architecture based on multi-agent systems (MAS that allows one to add or remove new evaporators online, without the need for reconfiguring, while maintaining temporal and functional restrictions in the system. We show clearly how we can get a greater scalability, the self-configuration of the network and the least overhead with a non-beacon or unslotted mode of the IEEE 802.15.4 protocol, as well as wireless communications and distributed architectures, which could be extremely helpful in the development process of networked control systems in large spatially-distributed plants, which involve many sensors and actuators. For this purpose, a fuzzy scheme is used to control a set of parallel evaporator air-conditioning systems, with temperature and relative humidity control as a multi-input and multi-output closed loop system; in addition, a general architecture is presented, which implements multiple control loops closed over a communication network, integrating the analysis and validation method for multi
10. Hydrotherapy for the Treatment of Pain in People with Multiple Sclerosis: A Randomized Controlled Trial
Castro-Sánchez, Adelaida María; Matarán-Peñarrocha, Guillermo A.; Lara-Palomo, Inmaculada; Saavedra-Hernández, Manuel; Arroyo-Morales, Manuel; Moreno-Lorenzo, Carmen
2011-01-01
Background. Multiple sclerosis (MS) is a chronic demyelinating neurological disease. Several studies have reported that complementary and alternative therapies can have positive effects against pain in these patients. Objective. The objective was to investigate the effectiveness of an Ai-Chi aquatic exercise program against pain and other symptoms in MS patients. Methods. In this randomized controlled trial, 73 MS patients were randomly assigned to an experimental or control group for a 20-we...
11. Use of wiener nonlinear MPC to control a CSTR with multiple steady state
Lusson Cervantes, A.; Agamennoni, O.E.; Figueroa, J.L.
2003-01-01
In this paper a Nonlinear Model Predictive Control based on a Wiener Model with a Piecewise Linear gain is presented. The major advantages of this algorithm is that it retains all the interesting properties of the classical linear MPC and the computations are easy to solve due to the canonical structure of the nonlinear gain. The proposed control scheme is applied to a nonlinear CSTR that presents multiple steady states.
12. Towards a decision support system for control of multiple food safety hazards in raw milk production
Spiegel, van der M.; Sterrenburg, P.; Haasnoot, W.; Fels-Klerx, van der H.J.
2013-01-01
Decision support systems (DSS) for controlling multiple food safety hazards in raw milk production have not yet been developed, but the underlying components are fragmentarily available. This article presents the state-of-the-art of essential DSS elements for judging food safety compliance of raw
13. All Set! Evidence of Simultaneous Attentional Control Settings for Multiple Target Colors
Irons, Jessica L.; Folk, Charles L.; Remington, Roger W.
2012-01-01
Although models of visual search have often assumed that attention can only be set for a single feature or property at a time, recent studies have suggested that it may be possible to maintain more than one attentional control setting. The aim of the present study was to investigate whether spatial attention could be guided by multiple attentional…
14. Evaluation of biases present in the cohort multiple randomised controlled trial design : a simulation study
Candlish, Jane; Pate, Alexander; Sperrin, Matthew; Staa, Tjeerd P van
2017-01-01
BACKGROUND: The cohort multiple randomised controlled trial (cmRCT) design provides an opportunity to incorporate the benefits of randomisation within clinical practice; thus reducing costs, integrating electronic healthcare records, and improving external validity. This study aims to address a key
15. Comparison of Intelligibility Measures for Adults with Parkinson's Disease, Adults with Multiple Sclerosis, and Healthy Controls
Stipancic, Kaila L.; Tjaden, Kris; Wilding, Gregory
2016-01-01
Purpose: This study obtained judgments of sentence intelligibility using orthographic transcription for comparison with previously reported intelligibility judgments obtained using a visual analog scale (VAS) for individuals with Parkinson's disease and multiple sclerosis and healthy controls (K. Tjaden, J. E. Sussman, & G. E. Wilding, 2014).…
16. Novel approach for independent control of brain hypothermia and systemic normothermia: cerebral selective deep hypothermia for refractory cardiac arrest.
Wang, Chih-Hsien; Lin, Yu-Ting; Chou, Heng-Wen; Wang, Yi-Chih; Hwang, Joey-Jen; Gilbert, John R; Chen, Yih-Sharng
2017-08-01
A 38-year-old man was found unconscious, alone in the driver's seat of his car. The emergency medical team identified his condition as pulseless ventricular tachycardia. Defibrillation was attempted but failed. Extracorporeal membrane oxygenation (ECMO) was started in the emergency room 52 min after the estimated arrest following the extracorporeal cardiopulmonary resuscitation (ECPR) protocol in our center. The initial prognosis under the standard protocol was <25% chance of survival. A novel adjunctive to our ECPR protocol, cerebral selective deep (<30°C) hypothermia (CSDH), was applied. CSDH adds a second independent femoral access extracorporeal circuit, perfusing cold blood into the patient's common carotid artery. The ECMO and CSDH circuits demonstrated independent control of cerebral and core temperatures. Nasal temperature was lowered to below 30°C for 12 hours while core was maintained at normothermia. The patient was discharged without significant neurological deficit 32 days after the initial arrest. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.
17. An integrated control strategy for the composite braking system of an electric vehicle with independently driven axles
Sun, Fengchun; Liu, Wei; He, Hongwen; Guo, Hongqiang
2016-08-01
For an electric vehicle with independently driven axles, an integrated braking control strategy was proposed to coordinate the regenerative braking and the hydraulic braking. The integrated strategy includes three modes, namely the hybrid composite mode, the parallel composite mode and the pure hydraulic mode. For the hybrid composite mode and the parallel composite mode, the coefficients of distributing the braking force between the hydraulic braking and the two motors' regenerative braking were optimised offline, and the response surfaces related to the driving state parameters were established. Meanwhile, the six-sigma method was applied to deal with the uncertainty problems for reliability. Additionally, the pure hydraulic mode is activated to ensure the braking safety and stability when the predictive failure of the response surfaces occurs. Experimental results under given braking conditions showed that the braking requirements could be well met with high braking stability and energy regeneration rate, and the reliability of the braking strategy was guaranteed on general braking conditions.
18. Auditory decision aiding in supervisory control of multiple unmanned aerial vehicles.
Donmez, Birsen; Cummings, M L; Graham, Hudson D
2009-10-01
19. Pneumonia is an independent risk factor for pyogenic liver abscess: A population-based, nested, case-control study.
Ho, Sai-Wai; Yeh, Chao-Bin; Yang, Shun-Fa; Yeh, Han-Wei; Huang, Jing-Yang; Teng, Ying-Hock
2017-01-01
Bacteremic pneumonia is considered a potential cause of distal organ abscess formation. Therefore, we hypothesize that pneumonia is a risk factor for pyogenic liver abscess (PLA).The aim of this study is to explore the association between pneumonia and PLA. A nationwide, population-based, nested, case-control study was conducted using data from the Taiwan National Health Insurance Research Database. In total, 494 patients with PLA and 1,976 propensity score matched controls were enrolled. Conditional logistic regression was used to estimate adjusted odds ratios (aORs) in patients with exposure to pneumonia before PLA. After matched and adjusted for confounding factors including age, sex, urbanization, income, chronic liver disease, alcohol-related disease, biliary stone, chronic kidney disease, diabetes mellitus, chronic liver disease, and cancer, hospitalization for pneumonia remained an independent risk factor for PLA with an aORs of 2.104 [95% confidence interval (CI) = 1.309-3.379, p = 0.0021]. Moreover, the aORs were significantly higher among patients hospitalized for pneumonia within 30 days (aORs = 10.73, 95% CI = 3.381-34.054), 30-90 days (aORs = 4.698, 95% CI = 1.541-14.327) and 90-180 (aORs = 4.000, 95% CI = 1.158-13.817) days before PLA diagnosis. Pneumonia is an independent risk factor for subsequent PLA. Moreover, hospitalization for pneumonia within 180 days before PLA diagnosis was associated with an increased risk of PLA.
20. P2X7-Regulated Protection from Exacerbations and Loss of Control Is Independent of Asthma Maintenance Therapy
Manthei, David M.; Seibold, Max A.; Ahn, Kwangmi; Bleecker, Eugene; Boushey, Homer A.; Calhoun, William J.; Castro, Mario; Chinchili, Vernon M.; Fahy, John V.; Hawkins, Greg A.; Icitovic, Nicolina; Israel, Elliot; Jarjour, Nizar N.; King, Tonya; Kraft, Monica; Lazarus, Stephen C.; Lehman, Erik; Martin, Richard J.; Meyers, Deborah A.; Peters, Stephen P.; Sheerar, Dagna; Shi, Lei; Sutherland, E. Rand; Szefler, Stanley J.; Wechsler, Michael E.; Sorkness, Christine A.; Lemanske, Robert F.
2013-01-01
Rationale: The function of the P2X7 nucleotide receptor protects against exacerbation in people with mild-intermittent asthma during viral illnesses, but the impact of disease severity and maintenance therapy has not been studied. Objectives: To evaluate the association between P2X7, asthma exacerbations, and incomplete symptom control in a more diverse population. Methods: A matched P2RX7 genetic case-control was performed with samples from Asthma Clinical Research Network trial participants enrolled before July 2006, and P2X7 pore activity was determined in whole blood samples as an ancillary study to two trials completed subsequently. Measurements and Main Results: A total of 187 exacerbations were studied in 742 subjects, and the change in asthma symptom burden was studied in an additional 110 subjects during a trial of inhaled corticosteroids (ICS) dose optimization. African American carriers of the minor G allele of the rs2230911 loss-of-function single nucleotide polymorphism were more likely to have a history of prednisone use in the previous 12 months, with adjustment for ICS and long-acting β2-agonists use (odds ratio, 2.7; 95% confidence interval, 1.2–6.2; P = 0.018). Despite medium-dose ICS, attenuated pore function predicted earlier exacerbations in incompletely controlled patients with moderate asthma (hazard ratio, 3.2; confidence interval, 1.1–9.3; P = 0.033). After establishing control with low-dose ICS in patients with mild asthma, those with attenuated pore function had more asthma symptoms, rescue albuterol use, and FEV1 reversal (P < 0.001, 0.03, and 0.03, respectively) during the ICS adjustment phase. Conclusions: P2X7 pore function protects against exacerbations of asthma and loss of control, independent of baseline severity and the maintenance therapy. PMID:23144325
1. Independent predictors of enteric fistula and abdominal sepsis after damage control laparotomy: results from the prospective AAST Open Abdomen registry.
Bradley, Matthew J; Dubose, Joseph J; Scalea, Thomas M; Holcomb, John B; Shrestha, Binod; Okoye, Obi; Inaba, Kenji; Bee, Tiffany K; Fabian, Timothy C; Whelan, James F; Ivatury, Rao R
2013-10-01
Enterocutaneous fistula (ECF), enteroatmospheric fistula (EAF), and intra-abdominal sepsis/abscess (IAS) are major challenges for surgeons caring for patients undergoing damage control laparotomy after trauma. To determine independent predictors of ECF, EAF, or IAS in patients undergoing damage control laparotomy after trauma, using the AAST Open Abdomen Registry. The AAST Open Abdomen registry of patients with an open abdomen following damage control laparotomy was used to identify patients who developed ECF, EAF, or IAS and to compare these patients with those without these complications. Univariate analyses were performed to compare these groups of patients. Variables from univariate analyses differing at P IAS. Fourteen level I trauma centers. A total of 517 patients with an open abdomen following damage control laparotomy. Complication of ECF, EAF, or IAS. More patients in the ECF/EAF/IAS group than in the group without these complications underwent bowel resection (63 of 111 patients [57%] vs 133 of 406 patients [33%]; P 48 hours after surgery, the ECF/EAF/IAS group received more colloids (P IAS group underwent almost twice as many abdominal reexplorations as did the group without these complications (mean [SD] number, 4.1 [4.1] vs 2.2 [3.4]; P IAS were a large bowel resection (adjusted odds ratio [AOR], 3.56 [95% CI, 1.88-6.76]; P 48 hours of between 5 and 10 L (AOR, 2.11 [95% CI, 1.15-3.88]; P = .02) or more than 10 L (AOR, 1.93 [95% CI, 1.04-3.57]; P = .04), and an increasing number of reexplorations (AOR, 1.14 [95% CI, 1.06-1.21]; P IAS in patients with an open abdomen after damage control laparotomy.
2. Evidence in Support of the Independent Channel Model Describing the Sensorimotor Control of Human Stance Using a Humanoid Robot.
Pasma, Jantsje H; Assländer, Lorenz; van Kordelaar, Joost; de Kam, Digna; Mergner, Thomas; Schouten, Alfred C
2018-01-01
The Independent Channel (IC) model is a commonly used linear balance control model in the frequency domain to analyze human balance control using system identification and parameter estimation. The IC model is a rudimentary and noise-free description of balance behavior in the frequency domain, where a stable model representation is not guaranteed. In this study, we conducted firstly time-domain simulations with added noise, and secondly robot experiments by implementing the IC model in a real-world robot (PostuRob II) to test the validity and stability of the model in the time domain and for real world situations. Balance behavior of seven healthy participants was measured during upright stance by applying pseudorandom continuous support surface rotations. System identification and parameter estimation were used to describe the balance behavior with the IC model in the frequency domain. The IC model with the estimated parameters from human experiments was implemented in Simulink for computer simulations including noise in the time domain and robot experiments using the humanoid robot PostuRob II. Again, system identification and parameter estimation were used to describe the simulated balance behavior. Time series, Frequency Response Functions, and estimated parameters from human experiments, computer simulations, and robot experiments were compared with each other. The computer simulations showed similar balance behavior and estimated control parameters compared to the human experiments, in the time and frequency domain. Also, the IC model was able to control the humanoid robot by keeping it upright, but showed small differences compared to the human experiments in the time and frequency domain, especially at high frequencies. We conclude that the IC model, a descriptive model in the frequency domain, can imitate human balance behavior also in the time domain, both in computer simulations with added noise and real world situations with a humanoid robot. This
3. Evidence in Support of the Independent Channel Model Describing the Sensorimotor Control of Human Stance Using a Humanoid Robot
Jantsje H. Pasma
2018-03-01
Full Text Available The Independent Channel (IC model is a commonly used linear balance control model in the frequency domain to analyze human balance control using system identification and parameter estimation. The IC model is a rudimentary and noise-free description of balance behavior in the frequency domain, where a stable model representation is not guaranteed. In this study, we conducted firstly time-domain simulations with added noise, and secondly robot experiments by implementing the IC model in a real-world robot (PostuRob II to test the validity and stability of the model in the time domain and for real world situations. Balance behavior of seven healthy participants was measured during upright stance by applying pseudorandom continuous support surface rotations. System identification and parameter estimation were used to describe the balance behavior with the IC model in the frequency domain. The IC model with the estimated parameters from human experiments was implemented in Simulink for computer simulations including noise in the time domain and robot experiments using the humanoid robot PostuRob II. Again, system identification and parameter estimation were used to describe the simulated balance behavior. Time series, Frequency Response Functions, and estimated parameters from human experiments, computer simulations, and robot experiments were compared with each other. The computer simulations showed similar balance behavior and estimated control parameters compared to the human experiments, in the time and frequency domain. Also, the IC model was able to control the humanoid robot by keeping it upright, but showed small differences compared to the human experiments in the time and frequency domain, especially at high frequencies. We conclude that the IC model, a descriptive model in the frequency domain, can imitate human balance behavior also in the time domain, both in computer simulations with added noise and real world situations with a
4. The Dynamics and Sliding Mode Control of Multiple Cooperative Welding Robot Manipulators
Bin Zi
2012-08-01
Full Text Available This paper deals with the design, dynamic modelling and sliding mode control of multiple cooperative welding robot manipulators (MWRMs. The MWRMs can handle complex tasks that are difficult or even impossible for a single manipulator. The kinematics and dynamics of the MWRMs are studied on the basis of the Denavit-Hartenberg and Lagrange method. Following that, considering the MWRM system with nonlinear and unknown disturbances, a non-singular terminal sliding mode control strategy is designed. By means of the Lyapunov function, the stability of the controller is proved. Simulation results indicate that the good control performance of the MWRMs is achieved by the non-singular terminal sliding mode controller, which also illustrates the correctness of the dynamic modelling and effectiveness of the proposed control strategy.
5. Front-end module readout and control electronics for the PHENIX Multiplicity Vertex Detector
Ericson, M.N.; Allen, M.D.; Boissevain, J.
1997-11-01
Front-end module (FEM) readout and control are implemented as modular, high-density, reprogrammable functions in the PHENIX Multiplicity Vertex Detector. FEM control is performed by the heap manager, an FPGA-based circuit in the FEM unit. Each FEM has 256 channels of front-end electronics, readout, and control, all located on an MCM. Data readout, formatting, and control are performed by the heap manager along with 4 interface units that reside outside the MVD detector cylinder. This paper discusses the application of a generic heap manager and the addition of 4 interface module types to meet the specific control and data readout needs of the MVD. Unit functioning, interfaces, timing, data format, and communication rates will be discussed in detail. In addition, subsystem issues regarding mode control, serial architecture and functions, error handling, and FPGA implementation and programming will be presented
6. Design project of the dosimetry control system in the independent CO2 loop for cooling the samples irradiated in the RA reactor vertical experimental channels, Vol. V
1964-01-01
Design project of the dosimetry control system in the independent CO 2 loop for cooling the samples irradiated in the RA reactor vertical experimental channels includes the following: calculations of CO 2 gas activity, design of the dosimetry control system, review of the changes that should be done in the RA reactor building for installing the independent CO 2 loop, specification of the materials with cost estimation, engineering drawings of the system [sr
7. Real-Time Optimal Flood Control Decision Making and Risk Propagation Under Multiple Uncertainties
Zhu, Feilin; Zhong, Ping-An; Sun, Yimeng; Yeh, William W.-G.
2017-12-01
Multiple uncertainties exist in the optimal flood control decision-making process, presenting risks involving flood control decisions. This paper defines the main steps in optimal flood control decision making that constitute the Forecast-Optimization-Decision Making (FODM) chain. We propose a framework for supporting optimal flood control decision making under multiple uncertainties and evaluate risk propagation along the FODM chain from a holistic perspective. To deal with uncertainties, we employ stochastic models at each link of the FODM chain. We generate synthetic ensemble flood forecasts via the martingale model of forecast evolution. We then establish a multiobjective stochastic programming with recourse model for optimal flood control operation. The Pareto front under uncertainty is derived via the constraint method coupled with a two-step process. We propose a novel SMAA-TOPSIS model for stochastic multicriteria decision making. Then we propose the risk assessment model, the risk of decision-making errors and rank uncertainty degree to quantify the risk propagation process along the FODM chain. We conduct numerical experiments to investigate the effects of flood forecast uncertainty on optimal flood control decision making and risk propagation. We apply the proposed methodology to a flood control system in the Daduhe River basin in China. The results indicate that the proposed method can provide valuable risk information in each link of the FODM chain and enable risk-informed decisions with higher reliability.
8. On decentralized adaptive full-order sliding mode control of multiple UAVs.
Xiang, Xianbo; Liu, Chao; Su, Housheng; Zhang, Qin
2017-11-01
9. Synthesis of nanoparticles in a flame aerosol reactor with independent and strict control of their size, crystal phase and morphology
Jiang Jingkun; Chen, D-R; Biswas, Pratim
2007-01-01
A flame aerosol reactor (FLAR) was developed to synthesize nanoparticles with desired properties (crystal phase and size) that could be independently controlled. The methodology was demonstrated for TiO 2 nanoparticles, and this is the first time that large sets of samples with the same size but different crystal phases (six different ratios of anatase to rutile in this work) were synthesized. The degree of TiO 2 nanoparticle agglomeration was determined by comparing the primary particle size distribution measured by scanning electron microscopy (SEM) to the mobility-based particle size distribution measured by online scanning mobility particle spectrometry (SMPS). By controlling the flame aerosol reactor conditions, both spherical unagglomerated particles and highly agglomerated particles were produced. To produce monodisperse nanoparticles, a high throughput multi-stage differential mobility analyser (MDMA) was used in series with the flame aerosol reactor. Nearly monodisperse nanoparticles (geometric standard deviation less than 1.05) could be collected in sufficient mass quantities (of the order of 10 mg) in reasonable time (1 h) that could be used in other studies such as determination of functionality or biological effects as a function of size
10. Synthesis of nanoparticles in a flame aerosol reactor with independent and strict control of their size, crystal phase and morphology
Jiang Jingkun; Chen, D-R; Biswas, Pratim [Aerosol and Air Quality Research Laboratory, Department of Energy, Environmental and Chemical Engineering, Washington University in St Louis, Campus Box 1180, St Louis, MO 63130 (United States)
2007-07-18
A flame aerosol reactor (FLAR) was developed to synthesize nanoparticles with desired properties (crystal phase and size) that could be independently controlled. The methodology was demonstrated for TiO{sub 2} nanoparticles, and this is the first time that large sets of samples with the same size but different crystal phases (six different ratios of anatase to rutile in this work) were synthesized. The degree of TiO{sub 2} nanoparticle agglomeration was determined by comparing the primary particle size distribution measured by scanning electron microscopy (SEM) to the mobility-based particle size distribution measured by online scanning mobility particle spectrometry (SMPS). By controlling the flame aerosol reactor conditions, both spherical unagglomerated particles and highly agglomerated particles were produced. To produce monodisperse nanoparticles, a high throughput multi-stage differential mobility analyser (MDMA) was used in series with the flame aerosol reactor. Nearly monodisperse nanoparticles (geometric standard deviation less than 1.05) could be collected in sufficient mass quantities (of the order of 10 mg) in reasonable time (1 h) that could be used in other studies such as determination of functionality or biological effects as a function of size.
11. Coordinated voltage control for multiple wind plants in Eastern Wyoming. Analysis, field experience and validation
Miller, Nicholas; MacDowell, Jason; Chmiel, Gary; Konopinski, Ryan; Gautam, Durga [GE Energy, Schenectady, NY (United States); Laughter, Grant; Hagen, Dave [PacifiCorp., Salt Lake City, UT (United States)
2012-07-01
At high levels of wind power penetration, multiple wind plants may be the predominant generation resource over large geographic areas. Thus, not only do wind plants need to provide a high level of functionality, they must coordinate properly with each other. This paper describes the analysis and field testing of wind plant voltage controllers designed to improve system voltage performance through passive coordination. The described wind power plant controls can coordinate the real and reactive power response of multiple wind turbines and thereby make the plant function as a single ''grid friendly'' power generation source. For this application, involving seven large wind plants with predominantly GE wind turbines in Eastern Wyoming, the voltage portion of the controllers were configured and tuned to allow the collective reactive power response of multiple wind plants in the region to work well together. This paper presents the results of the initial configuration and tuning study, and the results of the subsequent field tuning and testing of the modified controls. The paper also presents some comparisons of the measured field performance with the stability simulation models, which show that the available wind plant models provide accurate, high fidelity results for actual operating conditions of commercial wind power plants. (orig.)
12. A Telerehabilitation Program Improves Postural Control in Multiple Sclerosis Patients: A Spanish Preliminary Study
Rosa Ortiz-Gutiérrez
2013-10-01
Full Text Available Postural control disorders are among the most frequent motor disorder symptoms associated with multiple sclerosis. This study aims to demonstrate the potential improvements in postural control among patients with multiple sclerosis who complete a telerehabilitation program that represents a feasible alternative to physical therapy for situations in which conventional treatment is not available. Fifty patients were recruited. Control group (n = 25 received physiotherapy treatment twice a week (40 min per session. Experimental group (n = 25 received monitored telerehabilitation treatment via videoconference using the Xbox 360® and Kinect console. Experimental group attended 40 sessions, four sessions per week (20 min per session.The treatment schedule lasted 10 weeks for both groups. A computerized dynamic posturography (Sensory Organization Test was used to evaluate all patients at baseline and at the end of the treatment protocol. Results showed an improvement over general balance in both groups. Visual preference and the contribution of vestibular information yielded significant differences in the experimental group. Our results demonstrated that a telerehabilitation program based on a virtual reality system allows one to optimize the sensory information processing and integration systems necessary to maintain the balance and postural control of people with multiple sclerosis. We suggest that our virtual reality program enables anticipatory PC and response mechanisms and might serve as a successful therapeutic alternative in situations in which conventional therapy is not readily available.
13. A Telerehabilitation Program Improves Postural Control in Multiple Sclerosis Patients: A Spanish Preliminary Study
Ortiz-Gutiérrez, Rosa; Cano-de-la-Cuerda, Roberto; Galán-del-Río, Fernando; Alguacil-Diego, Isabel María; Palacios-Ceña, Domingo; Miangolarra-Page, Juan Carlos
2013-01-01
Postural control disorders are among the most frequent motor disorder symptoms associated with multiple sclerosis. This study aims to demonstrate the potential improvements in postural control among patients with multiple sclerosis who complete a telerehabilitation program that represents a feasible alternative to physical therapy for situations in which conventional treatment is not available. Fifty patients were recruited. Control group (n = 25) received physiotherapy treatment twice a week (40 min per session). Experimental group (n = 25) received monitored telerehabilitation treatment via videoconference using the Xbox 360® and Kinect console. Experimental group attended 40 sessions, four sessions per week (20 min per session).The treatment schedule lasted 10 weeks for both groups. A computerized dynamic posturography (Sensory Organization Test) was used to evaluate all patients at baseline and at the end of the treatment protocol. Results showed an improvement over general balance in both groups. Visual preference and the contribution of vestibular information yielded significant differences in the experimental group. Our results demonstrated that a telerehabilitation program based on a virtual reality system allows one to optimize the sensory information processing and integration systems necessary to maintain the balance and postural control of people with multiple sclerosis. We suggest that our virtual reality program enables anticipatory PC and response mechanisms and might serve as a successful therapeutic alternative in situations in which conventional therapy is not readily available. PMID:24185843
14. Hierarchical Robot Control System and Method for Controlling Select Degrees of Freedom of an Object Using Multiple Manipulators
Abdallah, Muhammad E. (Inventor); Platt, Robert (Inventor); Wampler, II, Charles W. (Inventor)
2013-01-01
A robotic system includes a robot having manipulators for grasping an object using one of a plurality of grasp types during a primary task, and a controller. The controller controls the manipulators during the primary task using a multiple-task control hierarchy, and automatically parameterizes the internal forces of the system for each grasp type in response to an input signal. The primary task is defined at an object-level of control, e.g., using a closed-chain transformation, such that only select degrees of freedom are commanded for the object. A control system for the robotic system has a host machine and algorithm for controlling the manipulators using the above hierarchy. A method for controlling the system includes receiving and processing the input signal using the host machine, including defining the primary task at the object-level of control, e.g., using a closed-chain definition, and parameterizing the internal forces for each of grasp type.
15. Full-order optimal compensators for flow control: the multiple inputs case
Semeraro, Onofrio; Pralits, Jan O.
2018-03-01
Flow control has been the subject of numerous experimental and theoretical works. We analyze full-order, optimal controllers for large dynamical systems in the presence of multiple actuators and sensors. The full-order controllers do not require any preliminary model reduction or low-order approximation: this feature allows us to assess the optimal performance of an actuated flow without relying on any estimation process or further hypothesis on the disturbances. We start from the original technique proposed by Bewley et al. (Meccanica 51(12):2997-3014, 2016. https://doi.org/10.1007/s11012-016-0547-3), the adjoint of the direct-adjoint (ADA) algorithm. The algorithm is iterative and allows bypassing the solution of the algebraic Riccati equation associated with the optimal control problem, typically infeasible for large systems. In this numerical work, we extend the ADA iteration into a more general framework that includes the design of controllers with multiple, coupled inputs and robust controllers (H_{∞} methods). First, we demonstrate our results by showing the analytical equivalence between the full Riccati solutions and the ADA approximations in the multiple inputs case. In the second part of the article, we analyze the performance of the algorithm in terms of convergence of the solution, by comparing it with analogous techniques. We find an excellent scalability with the number of inputs (actuators), making the method a viable way for full-order control design in complex settings. Finally, the applicability of the algorithm to fluid mechanics problems is shown using the linearized Kuramoto-Sivashinsky equation and the Kármán vortex street past a two-dimensional cylinder.
16. Coordinated Formation Control of Multiple Autonomous Underwater Vehicles for Pipeline Inspection
Xianbo Xiang
2010-02-01
Full Text Available This paper addresses the control problem of inspecting underwater pipeline on the seabed, with coordinated multiple autonomous underwater vehicles in a formation. Based on the leader-follower strategy, the dedicated nonlinear path following controller is rigorously built on Lyapunov-based design, driving a fleet of vehicles onto assigned parallel paths elevated and offset from the underwater pipeline, while keeping a triangle formation to capture complete 3D images for inspection. Due to the spatial-temporal decoupling characteristics of individual path following controller, the velocities of the followers can be adapted in the coordinated control level, only relying on the information of generalized along-path length from the leader, in order to build the desired formation. Thus, the communication variable broadcast from the leader is kept to a minimum, which is feasible under the severely constraints of acoustic communication bandwidth. Simulation results illustrate the efficiency of coordinated formation controller proposed for underwater pipeline inspection.
17. Comparison of Masking Level Difference in Patients with Multiple Sclerosis and Healthy Control Group
2012-03-01
Full Text Available Background and Aim: Multiple sclerosis (MS is a neurological disorder that involves central nervous system. Studies have showed that multiple sclerosis affects behavioral central auditory tests, such as masking release or masking level difference (MLD. The purpose of this study is to compare the masking level difference between multiple sclerosis patients and normal subjects.Methods: This cross sectional and non-interventional study was conducted on 32 multiple sclerosis patients aged between 20-50 years and 32 controls matched for age and gender in Faculty of Rehabilitation, Tehran University of Medical Sciences. masking level difference test was performed on each subject.Results: The mean masking level difference in the two groups was significantly different (p<0.01 however, gender did not prove to play a role in this difference.Conclusion: As part of the multiple sclerosis diagnosis panel, masking level difference test is an efficient modality for evaluation of hearing impairment and monitoring of rehabilitation progress.
18. Does a Wii-based exercise program enhance balance control of independently functioning older adults? A systematic review.
Laufer, Yocheved; Dar, Gali; Kodesh, Einat
2014-01-01
Exercise programs that challenge an individual's balance have been shown to reduce the risk of falls among older adults. Virtual reality computer-based technology that provides the user with opportunities to interact with virtual objects is used extensively for entertainment. There is a growing interest in the potential of virtual reality-based interventions for balance training in older adults. This work comprises a systematic review of the literature to determine the effects of intervention programs utilizing the Nintendo Wii console on balance control and functional performance in independently functioning older adults. STUDIES WERE OBTAINED BY SEARCHING THE FOLLOWING DATABASES: PubMed, CINAHL, PEDro, EMBASE, SPORTdiscus, and Google Scholar, followed by a hand search of bibliographic references of the included studies. Included were randomized controlled trials written in English in which Nintendo Wii Fit was used to enhance standing balance performance in older adults and compared with an alternative exercise treatment, placebo, or no treatment. Seven relevant studies were retrieved. The four studies examining the effect of Wii-based exercise compared with no exercise reported positive effects on at least one outcome measure related to balance performance in older adults. Studies comparing Wii-based training with alternative exercise programs generally indicated that the balance improvements achieved by Wii-based training are comparable with those achieved by other exercise programs. The review indicates that Wii-based exercise programs may serve as an alternative to more conventional forms of exercise aimed at improving balance control. However, due to the great variability between studies in terms of the intervention protocols and outcome measures, as well as methodological limitations, definitive recommendations as to optimal treatment protocols and the potential of such an intervention as a safe and effective home-based treatment cannot be made at this
19. Perturbation training to promote safe independent mobility post-stroke: study protocol for a randomized controlled trial.
Mansfield, Avril; Aqui, Anthony; Centen, Andrew; Danells, Cynthia J; DePaul, Vincent G; Knorr, Svetlana; Schinkel-Ivy, Alison; Brooks, Dina; Inness, Elizabeth L; McIlroy, William E; Mochizuki, George
2015-06-06
intervention: perturbation training. If effective, this training has the potential to not only prevent falls, but to also improve safe independent mobility and engagement in daily activities for those with stroke. Current Controlled Trials: ISRCTN05434601 .
20. Does a Wii-based exercise program enhance balance control of independently functioning older adults? A systematic review
Laufer, Yocheved; Dar, Gali; Kodesh, Einat
2014-01-01
Background Exercise programs that challenge an individual’s balance have been shown to reduce the risk of falls among older adults. Virtual reality computer-based technology that provides the user with opportunities to interact with virtual objects is used extensively for entertainment. There is a growing interest in the potential of virtual reality-based interventions for balance training in older adults. This work comprises a systematic review of the literature to determine the effects of intervention programs utilizing the Nintendo Wii console on balance control and functional performance in independently functioning older adults. Methods Studies were obtained by searching the following databases: PubMed, CINAHL, PEDro, EMBASE, SPORTdiscus, and Google Scholar, followed by a hand search of bibliographic references of the included studies. Included were randomized controlled trials written in English in which Nintendo Wii Fit was used to enhance standing balance performance in older adults and compared with an alternative exercise treatment, placebo, or no treatment. Results Seven relevant studies were retrieved. The four studies examining the effect of Wii-based exercise compared with no exercise reported positive effects on at least one outcome measure related to balance performance in older adults. Studies comparing Wii-based training with alternative exercise programs generally indicated that the balance improvements achieved by Wii-based training are comparable with those achieved by other exercise programs. Conclusion The review indicates that Wii-based exercise programs may serve as an alternative to more conventional forms of exercise aimed at improving balance control. However, due to the great variability between studies in terms of the intervention protocols and outcome measures, as well as methodological limitations, definitive recommendations as to optimal treatment protocols and the potential of such an intervention as a safe and effective home
1. Inverse comorbidity in multiple sclerosis
Thormann, Anja; Koch-Henriksen, Nils; Laursen, Bjarne
2016-01-01
onset of MS 1980-2005. We randomly matched each MS-case with five population controls. Comorbidity data were obtained from multiple, independent nationwide registries. Cases and controls were followed from January 1977 to the index date, and from the index date through December 2012. We controlled...
2. Multiple Model Predictive Hybrid Feedforward Control of Fuel Cell Power Generation System
Long Wu
2018-02-01
Full Text Available Solid oxide fuel cell (SOFC is widely considered as an alternative solution among the family of the sustainable distributed generation. Its load flexibility enables it adjusting the power output to meet the requirements from power grid balance. Although promising, its control is challenging when faced with load changes, during which the output voltage is required to be maintained as constant and fuel utilization rate kept within a safe range. Moreover, it makes the control even more intractable because of the multivariable coupling and strong nonlinearity within the wide-range operating conditions. To this end, this paper developed a multiple model predictive control strategy for reliable SOFC operation. The resistance load is regarded as a measurable disturbance, which is an input to the model predictive control as feedforward compensation. The coupling is accommodated by the receding horizon optimization. The nonlinearity is mitigated by the multiple linear models, the weighted sum of which serves as the final control execution. The merits of the proposed control structure are demonstrated by the simulation results.
3. Effects of Pilates exercises on sensory interaction, postural control and fatigue in patients with multiple sclerosis.
Soysal Tomruk, Melda; Uz, Muhammed Zahid; Kara, Bilge; İdiman, Egemen
2016-05-01
Decreased postural control, sensory integration deficits and fatigue are important problems that cause functional impairments in patients with multiple sclerosis (pwMS). To examine the effect of modified clinical Pilates exercises on sensory interaction and balance, postural control and fatigue in pwMS. Eleven patients with multiple sclerosis and 12 healthy matched controls were recruited in this study. Limits of stability and postural stability tests were used to evaluate postural control by Biodex Balance System and sensory interaction assessed. Fatigue was assessed by Modified Fatigue Impact Scale. Pilates exercises were applied two times a week for 10 weeks and measurements were repeated to pwMS after exercise training. Postural control and fatigue (except psychosocial parameter) of pwMS were significantly worser than healthy controls (pPilates training (ppilates exercises (p>0.05). Ten-week Pilates training is effective to improve sensory interaction and to decrease fatigue. Pilates exercises can be applied safely in ambulatory pwMS for enhance sensory interaction and balance and combat fatigue. More investigations are needed. Copyright © 2016 Elsevier B.V. All rights reserved.
4. Relationships between trunk performance, gait and postural control in persons with multiple sclerosis.
Freund, Jane E; Stetts, Deborah M; Vallabhajosula, Srikant
2016-06-30
Multiple sclerosis (MS) is a chronic progressive disease of the central nervous system. Compared to healthy individuals, persons with multiple sclerosis (PwMS) have increased postural sway in quiet stance, decreased gait speed and increased fall incidence. Trunk performance has been implicated in postural control, gait dysfunction, and fall prevention in older adults. However, the relationship of trunk performance to postural control and gait has not been adequately studied in PwMS. To compare trunk muscle structure and performance in PwMS to healthy age and gendered-matched controls (HC); to determine the effects of isometric trunk endurance testing on postural control in both populations; and to determine the relationship of trunk performance with postural control, gait and step activity in PwMS. Fifteen PwMS and HC completed ultrasound imaging of trunk muscles, 10 m walk test, isometric trunk endurance tests, and postural sway test. Participants wore a step activity monitor for 7 days. PwMS had worse isometric trunk endurance compared to HC. PwMS trunk flexion endurance negatively correlated to several postural control measures and positively correlated to gait speed and step activity. Clinicians should consider evaluation and interventions directed at impaired trunk endurance in PwMS.
5. Design and selection of load control strategies using a multiple objective model and evolutionary algorithms
Gomes, Alvaro; Antunes, Carlos Henggeler; Martins, Antonio Gomes
2005-01-01
This paper aims at presenting a multiple objective model to evaluate the attractiveness of the use of demand resources (through load management control actions) by different stakeholders and in diverse structure scenarios in electricity systems. For the sake of model flexibility, the multiple (and conflicting) objective functions of technical, economical and quality of service nature are able to capture distinct market scenarios and operating entities that may be interested in promoting load management activities. The computation of compromise solutions is made by resorting to evolutionary algorithms, which are well suited to tackle multiobjective problems of combinatorial nature herein involving the identification and selection of control actions to be applied to groups of loads. (Author)
6. A distributed Synchronous reservation multiple access control protocol for mobile Ad hoc networks
ZHANG Yanling; SUN Xianpu; LI Jiandong
2007-01-01
This study proposes a new multiple access control protocol named distributed synchronous reservation multiple access control protocol.in which the hidden and exposed terminal problems are solved,and the quality of service(QoS)requirements for real-time traffic are guaranteed.The protocol is founded on time division multiplex address and a different type of traffic is assigned to difierent priority,according to which a node should compete for and reserve the free slots in a different method.Moreover,there is a reservation acknowledgement process before data transmit in each reserved slot,so that the intruded terminal problem is solved.The throughput and average packets drop probability of this protocol are analyzed and simulated in a fully connected network.the results of which indicate that this protocol is efficient enough to support the real-time traffic.and it is more suitable to MANETs.
7. A nonlinear disturbance-decoupled elevation axis controller for the Multiple Mirror Telescope
Clark, Dusty; Trebisky, Tom; Powell, Keith
2008-07-01
The Multiple Mirror Telescope (MMT), upgraded in 2000 to a monolithic 6.5m primary mirror from its original array of six 1.8m primary mirrors, was commissioned with axis controllers designed early in the upgrade process without regard to structural resonances or the possibility of the need for digital filtering of the control axis signal path. Post-commissioning performance issues led us to investigate replacement of the original control system with a more modern digital controller with full control over the system filters and gain paths. This work, from system identification through controller design iteration by simulation, and pre-deployment hardware-in-the-loop testing, was performed using latest-generation tools with Matlab® and Simulink®. Using Simulink's Real Time Workshop toolbox to automatically generate C source code for the controller from the Simulink diagram and a custom target build script, we were able to deploy the new controller into our existing software infrastructure running Wind River's VxWorks™real-time operating system. This paper describes the process of the controller design, including system identification data collection, with discussion of implementation of non-linear control modes and disturbance decoupling, which became necessary to obtain acceptable wind buffeting rejection.
8. Formation Learning Control of Multiple Autonomous Underwater Vehicles With Heterogeneous Nonlinear Uncertain Dynamics.
Yuan, Chengzhi; Licht, Stephen; He, Haibo
2017-09-26
In this paper, a new concept of formation learning control is introduced to the field of formation control of multiple autonomous underwater vehicles (AUVs), which specifies a joint objective of distributed formation tracking control and learning/identification of nonlinear uncertain AUV dynamics. A novel two-layer distributed formation learning control scheme is proposed, which consists of an upper-layer distributed adaptive observer and a lower-layer decentralized deterministic learning controller. This new formation learning control scheme advances existing techniques in three important ways: 1) the multi-AUV system under consideration has heterogeneous nonlinear uncertain dynamics; 2) the formation learning control protocol can be designed and implemented by each local AUV agent in a fully distributed fashion without using any global information; and 3) in addition to the formation control performance, the distributed control protocol is also capable of accurately identifying the AUVs' heterogeneous nonlinear uncertain dynamics and utilizing experiences to improve formation control performance. Extensive simulations have been conducted to demonstrate the effectiveness of the proposed results.
9. Design and testing of an independently controlled urea SCR retrofit system for the reduction of NOx emissions from marine diesels.
Johnson, Derek R; Bedick, Clinton R; Clark, Nigel N; McKain, David L
2009-05-15
Diesel engine emissions for on-road, stationary and marine applications are regulated in the United States via standards set by the Environmental Protection Agency (EPA). A major component of diesel exhaust that is difficult to reduce is nitrogen oxides (NOx). Selective catalytic reduction (SCR) has been in use for many years for stationary applications, including external combustion boilers, and is promising for NOx abatement as a retrofit for mobile applications where diesel compression ignition engines are used. The research presented in this paper is the first phase of a program focused on the reduction of NOx by use of a stand-alone urea injection system, applicable to marine diesel engines typical of work boats (e.g., tugs). Most current urea SCR systems communicate with engine controls to predict NOx emissions based on signals such as torque and engine speed, however many marine engines in use still employ mechanical injection technology and lack electronic communication abilities. The system developed and discussed in this paper controls NOx emissions independentof engine operating parameters and measures NOx and exhaust flow using the following exhaust sensor inputs: absolute pressure, differential pressure, temperature, and NOx concentration. These sensor inputs were integrated into an independent controller and open loop architecture to estimate the necessary amount of urea needed, and the controller uses pulse width modulation (PWM) to power an automotive fuel injector for airless urea delivery. The system was tested in a transient test cell on a 350 hp engine certified at 4 g/bhp-hr of NOx, with a goal of reducing the engine out NOx levels by 50%. NOx reduction capabilities of 41-67% were shown on the non road transient cycle (NRTC) and ICOMIA E5 steady state cycles with system optimization during testing to minimize the dilute ammonia slip to cycle averages of 5-7 ppm. The goal of 50% reduction of NOx can be achieved dependent upon cycle. Further
10. FPGA implementation of high-frequency multiple PWM for variable voltage variable frequency controller
Boumaaraf, Abdelâali, E-mail: aboumaaraf@yahoo.fr [Université Abbès Laghrour, Laboratoire des capteurs, Instrumentations et procédés (LCIP), Khenchela (Algeria); University of Farhat Abbas Setif1, Sétif, 19000 (Algeria); Mohamadi, Tayeb [University of Farhat Abbas Setif1, Sétif, 19000 (Algeria); Gourmat, Laïd [Université Abbès Laghrour, Khenchela, 40000 (Algeria)
2016-07-25
In this paper, we present the FPGA implementation of the multiple pulse width modulation (MPWM) signal generation with repetition of data segments, applied to the variable frequency variable voltage systems and specially at to the photovoltaic water pumping system, in order to generate a signal command very easily between 10 Hz to 60 Hz with a small frequency and reduce the cost of the control system.
11. Participant recruitment into a randomised controlled trial of exercise therapy for people with multiple sclerosis
Carter, Anouska; Humphreys, Liam; Snowdon, Nicky; Sharrack, Basil; Daley, Amanda; Petty, Jane; Woodroofe, Nicola; Saxton, John
2015-01-01
Background The success of a clinical trial is often dependant on whether recruitment targets can be met in the required time frame. Despite an increase in research into the benefits of exercise in people with multiple sclerosis (PwMS), no trial has reported detailed data on effective recruitment strategies for large-scale randomised controlled trials. The main purpose of this report is to provide a detailed outline of recruitment strategies, rates and estimated costs in the Exercise Intervent...
12. Evidence from intrinsic activity that asymmetry of the human brain is controlled by multiple factors
Liu, Hesheng; Stufflebeam, Steven M.; Sepulcre, Jorge; Hedden, Trey; Buckner, Randy L.
2009-01-01
Cerebral lateralization is a fundamental property of the human brain and a marker of successful development. Here we provide evidence that multiple mechanisms control asymmetry for distinct brain systems. Using intrinsic activity to measure asymmetry in 300 adults, we mapped the most strongly lateralized brain regions. Both men and women showed strong asymmetries with a significant, but small, group difference. Factor analysis on the asymmetric regions revealed 4 separate factors that each ac...
13. Synthesis of Carbon Dots with Multiple Color Emission by Controlled Graphitization and Surface Functionalization.
Miao, Xiang; Qu, Dan; Yang, Dongxue; Nie, Bing; Zhao, Yikang; Fan, Hongyou; Sun, Zaicheng
2018-01-01
Multiple-color-emissive carbon dots (CDots) have potential applications in various fields such as bioimaging, light-emitting devices, and photocatalysis. The majority of the current CDots to date exhibit excitation-wavelength-dependent emissions with their maximum emission limited at the blue-light region. Here, a synthesis of multiple-color-emission CDots by controlled graphitization and surface function is reported. The CDots are synthesized through controlled thermal pyrolysis of citric acid and urea. By regulating the thermal-pyrolysis temperature and ratio of reactants, the maximum emission of the resulting CDots gradually shifts from blue to red light, covering the entire light spectrum. Specifically, the emission position of the CDots can be tuned from 430 to 630 nm through controlling the extent of graphitization and the amount of surface functional groups, COOH. The relative photoluminescence quantum yields of the CDots with blue, green, and red emission reach up to 52.6%, 35.1%, and 12.9%, respectively. Furthermore, it is demonstrated that the CDots can be uniformly dispersed into epoxy resins and be fabricated as transparent CDots/epoxy composites for multiple-color- and white-light-emitting devices. This research opens a door for developing low-cost CDots as alternative phosphors for light-emitting devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
14. Getting the balance right: a randomised controlled trial of physiotherapy and Exercise Interventions for ambulatory people with multiple sclerosis.
Coote, Susan
2009-01-01
BACKGROUND: People with Multiple Sclerosis have a life long need for physiotherapy and exercise interventions due to the progressive nature of the disease and their greater risk of the complications of inactivity. The Multiple Sclerosis Society of Ireland run physiotherapy, yoga and exercise classes for their members, however there is little evidence to suggest which form of physical activity optimises outcome for people with the many and varied impairments associated with MS. METHODS AND DESIGN: This is a multi-centre, single blind, block randomised, controlled trial. Participants will be recruited via the ten regional offices of MS Ireland. Telephone screening will establish eligibility and stratification according to the mobility section of the Guys Neurological Disability Scale. Once a block of people of the same strand in the same geographical region have given consent, participants will be randomised. Strand A will concern individuals with MS who walk independently or use one stick to walk outside. Participants will be randomised to yoga, physiotherapy led exercise class, fitness instructor led exercise class or to a control group who don\\'t change their exercise habits.Strand B will concern individuals with MS who walk with bilateral support or a rollator, they may use a wheelchair for longer distance outdoors. Participants will be randomised to 1:1 Physiotherapist led intervention, group intervention led by Physiotherapist, group yoga intervention or a control group who don\\'t change their exercise habits. Participants will be assessed by physiotherapist who is blind to the group allocation at week 1, week 12 (following 10 weeks intervention or control), and at 12 week follow up. The primary outcome measure for both strands is the Multiple Sclerosis Impact Scale. Secondary outcomes are Modified Fatigue Impact Scale, 6 Minute Walk test, and muscle strength measured with hand held dynamometry. Strand B will also use Berg Balance Test and the Modified
15. Getting the balance right: a randomised controlled trial of physiotherapy and Exercise Interventions for ambulatory people with multiple sclerosis.
Coote, Susan; Garrett, Maria; Hogan, Neasa; Larkin, Aidan; Saunders, Jean
2009-07-16
People with Multiple Sclerosis have a life long need for physiotherapy and exercise interventions due to the progressive nature of the disease and their greater risk of the complications of inactivity. The Multiple Sclerosis Society of Ireland run physiotherapy, yoga and exercise classes for their members, however there is little evidence to suggest which form of physical activity optimises outcome for people with the many and varied impairments associated with MS. This is a multi-centre, single blind, block randomised, controlled trial. Participants will be recruited via the ten regional offices of MS Ireland. Telephone screening will establish eligibility and stratification according to the mobility section of the Guys Neurological Disability Scale. Once a block of people of the same strand in the same geographical region have given consent, participants will be randomised. Strand A will concern individuals with MS who walk independently or use one stick to walk outside. Participants will be randomised to yoga, physiotherapy led exercise class, fitness instructor led exercise class or to a control group who don't change their exercise habits.Strand B will concern individuals with MS who walk with bilateral support or a rollator, they may use a wheelchair for longer distance outdoors. Participants will be randomised to 1:1 Physiotherapist led intervention, group intervention led by Physiotherapist, group yoga intervention or a control group who don't change their exercise habits. Participants will be assessed by physiotherapist who is blind to the group allocation at week 1, week 12 (following 10 weeks intervention or control), and at 12 week follow up. The primary outcome measure for both strands is the Multiple Sclerosis Impact Scale. Secondary outcomes are Modified Fatigue Impact Scale, 6 Minute Walk test, and muscle strength measured with hand held dynamometry. Strand B will also use Berg Balance Test and the Modified Ashworth Scale. Confounding variables such
16. Getting the Balance Right: A randomised controlled trial of physiotherapy and Exercise Interventions for ambulatory people with multiple sclerosis
Larkin Aidan
2009-07-01
Full Text Available Abstract Background People with Multiple Sclerosis have a life long need for physiotherapy and exercise interventions due to the progressive nature of the disease and their greater risk of the complications of inactivity. The Multiple Sclerosis Society of Ireland run physiotherapy, yoga and exercise classes for their members, however there is little evidence to suggest which form of physical activity optimises outcome for people with the many and varied impairments associated with MS. Methods and design This is a multi-centre, single blind, block randomised, controlled trial. Participants will be recruited via the ten regional offices of MS Ireland. Telephone screening will establish eligibility and stratification according to the mobility section of the Guys Neurological Disability Scale. Once a block of people of the same strand in the same geographical region have given consent, participants will be randomised. Strand A will concern individuals with MS who walk independently or use one stick to walk outside. Participants will be randomised to yoga, physiotherapy led exercise class, fitness instructor led exercise class or to a control group who don't change their exercise habits. Strand B will concern individuals with MS who walk with bilateral support or a rollator, they may use a wheelchair for longer distance outdoors. Participants will be randomised to 1:1 Physiotherapist led intervention, group intervention led by Physiotherapist, group yoga intervention or a control group who don't change their exercise habits. Participants will be assessed by physiotherapist who is blind to the group allocation at week 1, week 12 (following 10 weeks intervention or control, and at 12 week follow up. The primary outcome measure for both strands is the Multiple Sclerosis Impact Scale. Secondary outcomes are Modified Fatigue Impact Scale, 6 Minute Walk test, and muscle strength measured with hand held dynamometry. Strand B will also use Berg Balance Test
17. A multiple-time-scale approach to the control of ITBs on JET
Laborde, L.; Mazon, D.; Moreau, D. [EURATOM-CEA Association (DSM-DRFC), CEA Cadarache, 13 - Saint Paul lez Durance (France); Moreau, D. [Culham Science Centre, EFDA-JET, Abingdon, OX (United Kingdom); Ariola, M. [EURATOM/ENEA/CREATE Association, Univ. Napoli Federico II, Napoli (Italy); Cordoliani, V. [Ecole Polytechnique, 91 - Palaiseau (France); Tala, T. [EURATOM-Tekes Association, VTT Processes (Finland)
2005-07-01
The simultaneous real-time control of the current and temperature gradient profiles could lead to the steady state sustainment of an internal transport barrier (ITB) and so to a stationary optimized plasma regime. Recent experiments in JET have demonstrated significant progress in achieving such a control: different current and temperature gradient target profiles have been reached and sustained for several seconds using a controller based on a static linear model. It's worth noting that the inverse safety factor profile evolves on a slow time scale (resistive time) while the normalized electron temperature gradient reacts on a faster one (confinement time). Moreover these experiments have shown that the controller was sensitive to rapid plasma events such as transient ITBs during the safety factor profile evolution or MHD instabilities which modify the pressure profiles on the confinement time scale. In order to take into account the different dynamics of the controlled profiles and to better react to rapid plasma events the control technique is being improved by using a multiple-time-scale approximation. The paper describes the theoretical analysis and closed-loop simulations using a control algorithm based on two-time-scale state-space model. These closed-loop simulations using the full dynamic but linear model used for the controller design to simulate the plasma response have demonstrated that this new controller allows the normalized electron temperature gradient target profile to be reached faster than the one used in previous experiments. (A.C.)
18. A multiple-time-scale approach to the control of ITBs on JET
Laborde, L.; Mazon, D.; Moreau, D.; Moreau, D.; Ariola, M.; Cordoliani, V.; Tala, T.
2005-01-01
The simultaneous real-time control of the current and temperature gradient profiles could lead to the steady state sustainment of an internal transport barrier (ITB) and so to a stationary optimized plasma regime. Recent experiments in JET have demonstrated significant progress in achieving such a control: different current and temperature gradient target profiles have been reached and sustained for several seconds using a controller based on a static linear model. It's worth noting that the inverse safety factor profile evolves on a slow time scale (resistive time) while the normalized electron temperature gradient reacts on a faster one (confinement time). Moreover these experiments have shown that the controller was sensitive to rapid plasma events such as transient ITBs during the safety factor profile evolution or MHD instabilities which modify the pressure profiles on the confinement time scale. In order to take into account the different dynamics of the controlled profiles and to better react to rapid plasma events the control technique is being improved by using a multiple-time-scale approximation. The paper describes the theoretical analysis and closed-loop simulations using a control algorithm based on two-time-scale state-space model. These closed-loop simulations using the full dynamic but linear model used for the controller design to simulate the plasma response have demonstrated that this new controller allows the normalized electron temperature gradient target profile to be reached faster than the one used in previous experiments. (A.C.)
19. Simultaneous control of multiple instruments at the Advanced Technology Solar Telescope
Johansson, Erik M.; Goodrich, Bret
2012-09-01
The Advanced Technology Solar Telescope (ATST) is a 4-meter solar observatory under construction at Haleakala, Hawaii. The simultaneous use of multiple instruments is one of the unique capabilities that makes the ATST a premier ground based solar observatory. Control of the instrument suite is accomplished by the Instrument Control System (ICS), a layer of software between the Observatory Control System (OCS) and the instruments. The ICS presents a single narrow interface to the OCS and provides a standard interface for the instruments to be controlled. It is built upon the ATST Common Services Framework (CSF), an infrastructure for the implementation of a distributed control system. The ICS responds to OCS commands and events, coordinating and distributing them to the various instruments while monitoring their progress and reporting the status back to the OCS. The ICS requires no specific knowledge about the instruments. All information about the instruments used in an experiment is passed by the OCS to the ICS, which extracts and forwards the parameters to the appropriate instrument controllers. The instruments participating in an experiment define the active instrument set. A subset of those instruments must complete their observing activities in order for the experiment to be considered complete and are referred to as the must-complete instrument set. In addition, instruments may participate in eavesdrop mode, outside of the control of the ICS. All instrument controllers use the same standard narrow interface, which allows new instruments to be added without having to modify the interface or any existing instrument controllers.
20. Are Independent Probes Truly Independent?
Camp, Gino; Pecher, Diane; Schmidt, Henk G.; Zeelenberg, Rene
2009-01-01
The independent cue technique has been developed to test traditional interference theories against inhibition theories of forgetting. In the present study, the authors tested the critical criterion for the independence of independent cues: Studied cues not presented during test (and unrelated to test cues) should not contribute to the retrieval…
1. Multiple-Time-Scales Hierarchical Frequency Stability Control Strategy of Medium-Voltage Isolated Microgrid
Zhao, Zhuoli; Yang, Ping; Guerrero, Josep M.
2016-01-01
In this paper, an islanded medium-voltage (MV) microgrid placed in Dongao Island is presented, which integrates renewable-energy-based distributed generations (DGs), energy storage system (ESS), and local loads. In an isolated microgrid without connection to the main grid to support the frequency......, it is more complex to control and manage. Thus in order to maintain the frequency stability in multiple-time-scales, a hierarchical control strategy is proposed. The proposed control architecture divides the system frequency in three zones: (A) stable zone, (B) precautionary zone and (C) emergency zone...... of Zone B. Theoretical analysis, time-domain simulation and field test results under various conditions and scenarios in the Dongao Island microgrid are presented to prove the validity of the introduced control strategy....
2. Endocytosis-independent function of clathrin heavy chain in the control of basal NF-κB activation.
Man Lyang Kim
Full Text Available BACKGROUND: Nuclear factor-κB (NF-κB is a transcription factor that regulates the transcription of genes involved in a variety of biological processes, including innate and adaptive immunity, stress responses and cell proliferation. Constitutive or excessive NF-κB activity has been associated with inflammatory disorders and higher risk of cancer. In contrast to the mechanisms controlling inducible activation, the regulation of basal NF-κB activation is not well understood. Here we test whether clathrin heavy chain (CHC contributes to the regulation of basal NF-κB activity in epithelial cells. METHODOLOGY: Using RNA interference to reduce endogenous CHC expression, we found that CHC is required to prevent constitutive activation of NF-κB and gene expression. Immunofluorescence staining showed constitutive nuclear localization of the NF-κB subunit p65 in absence of stimulation after CHC knockdown. Elevated basal p65 nuclear localization is caused by constitutive phosphorylation and degradation of inhibitor of NF-κB alpha (IκBα through an IκB kinase α (IKKα-dependent mechanism. The role of CHC in NF-κB signaling is functionally relevant as constitutive expression of the proinflammatory chemokine interleukin-8 (IL-8, whose expression is regulated by NF-κB, was found after CHC knockdown. Disruption of clathrin-mediated endocytosis by chemical inhibition or depletion of the μ2-subunit of the endocytosis adaptor protein AP-2, and knockdown of clathrin light chain a (CHLa, failed to induce constitutive NF-κB activation and IL-8 expression, showing that CHC acts on NF-κB independently of endocytosis and CLCa. CONCLUSIONS: We conclude that CHC functions as a built-in molecular brake that ensures a tight control of basal NF-κB activation and gene expression in unstimulated cells. Furthermore, our data suggest a potential link between a defect in CHC expression and chronic inflammation disorder and cancer.
3. Investigating the Efficacy of Web-Based Transfer Training on Independent Wheelchair Transfers Through Randomized Controlled Trials.
Worobey, Lynn A; Rigot, Stephanie K; Hogaboom, Nathan S; Venus, Chris; Boninger, Michael L
2018-01-01
To determine the efficacy of a web-based transfer training module at improving transfer technique across 3 groups: web-based training, in-person training (current standard of practice), and a waitlist control group (WLCG); and secondarily, to determine subject factors that can be used to predict improvements in transfer ability after training. Randomized controlled trials. Summer and winter sporting events for disabled veterans. A convenience sample (N=71) of manual and power wheelchair users who could transfer independently. An individualized, in-person transfer training session or a web-based transfer training module. The WLCG received the web training at their follow-up visit. Transfer Assessment Instrument (TAI) part 1 score was used to assess transfers at baseline, skill acquisition immediately posttraining, and skill retention after a 1- to 2-day follow-up period. The in-person and web-based training groups improved their median (interquartile range) TAI scores from 7.98 (7.18-8.46) to 9.13 (8.57-9.58; P.05). A lower initial TAI score was found to be the only significant predictor of a larger percent change in TAI score after receiving training. Transfer training can improve technique with changes retained within a short follow-up window, even among experienced wheelchair users. Web-based transfer training demonstrated comparable improvements to in-person training. With almost half of the United States population consulting online resources before a health care professional, web-based training may be an effective method to increase knowledge translation. Copyright © 2017 American Congress of Rehabilitation Medicine. All rights reserved.
4. Vibration control of uncertain multiple launch rocket system using radial basis function neural network
Li, Bo; Rui, Xiaoting
2018-01-01
Poor dispersion characteristics of rockets due to the vibration of Multiple Launch Rocket System (MLRS) have always restricted the MLRS development for several decades. Vibration control is a key technique to improve the dispersion characteristics of rockets. For a mechanical system such as MLRS, the major difficulty in designing an appropriate control strategy that can achieve the desired vibration control performance is to guarantee the robustness and stability of the control system under the occurrence of uncertainties and nonlinearities. To approach this problem, a computed torque controller integrated with a radial basis function neural network is proposed to achieve the high-precision vibration control for MLRS. In this paper, the vibration response of a computed torque controlled MLRS is described. The azimuth and elevation mechanisms of the MLRS are driven by permanent magnet synchronous motors and supposed to be rigid. First, the dynamic model of motor-mechanism coupling system is established using Lagrange method and field-oriented control theory. Then, in order to deal with the nonlinearities, a computed torque controller is designed to control the vibration of the MLRS when it is firing a salvo of rockets. Furthermore, to compensate for the lumped uncertainty due to parametric variations and un-modeled dynamics in the design of the computed torque controller, a radial basis function neural network estimator is developed to adapt the uncertainty based on Lyapunov stability theory. Finally, the simulated results demonstrate the effectiveness of the proposed control system and show that the proposed controller is robust with regard to the uncertainty.
5. Consensus seeking, formation keeping, and trajectory tracking in multiple vehicle cooperative control
Ren, Wei
Cooperative control problems for multiple vehicle systems can be categorized as either formation control problems with applications to mobile robots, unmanned air vehicles, autonomous underwater vehicles, satellites, aircraft, spacecraft, and automated highway systems, or non-formation control problems such as task assignment, cooperative transport, cooperative role assignment, air traffic control, cooperative timing, and cooperative search. The cooperative control of multiple vehicle systems poses significant theoretical and practical challenges. For cooperative control strategies to be successful, numerous issues must be addressed. We consider three important and correlated issues: consensus seeking, formation keeping, and trajectory tracking. For consensus seeking, we investigate algorithms and protocols so that a team of vehicles can reach consensus on the values of the coordination data in the presence of imperfect sensors, communication dropout, sparse communication topologies, and noisy and unreliable communication links. The main contribution of this dissertation in this area is that we show necessary and/or sufficient conditions for consensus seeking with limited, unidirectional, and unreliable information exchange under fixed and switching interaction topologies (through either communication or sensing). For formation keeping, we apply a so-called "virtual structure" approach to spacecraft formation flying and multi-vehicle formation maneuvers. As a result, single vehicle path planning and trajectory generation techniques can be employed for the virtual structure while trajectory tracking strategies can be employed for each vehicle. The main contribution of this dissertation in this area is that we propose a decentralized architecture for multiple spacecraft formation flying in deep space with formation feedback introduced. This architecture ensures the necessary precision in the presence of actuator saturation, internal and external disturbances, and
6. Does a Wii-based exercise program enhance balance control of independently functioning older adults? A systematic review
Laufer Y
2014-10-01
Full Text Available Yocheved Laufer, Gali Dar, Einat Kodesh Physical Therapy Department, Faculty of Social Welfare and Health Sciences, University of Haifa, Haifa, Israel Background: Exercise programs that challenge an individual’s balance have been shown to reduce the risk of falls among older adults. Virtual reality computer-based technology that provides the user with opportunities to interact with virtual objects is used extensively for entertainment. There is a growing interest in the potential of virtual reality-based interventions for balance training in older adults. This work comprises a systematic review of the literature to determine the effects of intervention programs utilizing the Nintendo Wii console on balance control and functional performance in independently functioning older adults.Methods: Studies were obtained by searching the following databases: PubMed, CINAHL, PEDro, EMBASE, SPORTdiscus, and Google Scholar, followed by a hand search of bibliographic references of the included studies. Included were randomized controlled trials written in English in which Nintendo Wii Fit was used to enhance standing balance performance in older adults and compared with an alternative exercise treatment, placebo, or no treatment.Results: Seven relevant studies were retrieved. The four studies examining the effect of Wii-based exercise compared with no exercise reported positive effects on at least one outcome measure related to balance performance in older adults. Studies comparing Wii-based training with alternative exercise programs generally indicated that the balance improvements achieved by Wii-based training are comparable with those achieved by other exercise programs.Conclusion: The review indicates that Wii-based exercise programs may serve as an alternative to more conventional forms of exercise aimed at improving balance control. However, due to the great variability between studies in terms of the intervention protocols and outcome measures, as
7. A study on software-based sensing technology for multiple object control in AR video.
Jung, Sungmo; Song, Jae-Gu; Hwang, Dae-Joon; Ahn, Jae Young; Kim, Seoksoo
2010-01-01
Researches on Augmented Reality (AR) have recently received attention. With these, the Machine-to-Machine (M2M) market has started to be active and there are numerous efforts to apply this to real life in all sectors of society. To date, the M2M market has applied the existing marker-based AR technology in entertainment, business and other industries. With the existing marker-based AR technology, a designated object can only be loaded on the screen from one marker and a marker has to be added to load on the screen the same object again. This situation creates a problem where the relevant marker'should be extracted and printed in screen so that loading of the multiple objects is enabled. However, since the distance between markers will not be measured in the process of detecting and copying markers, the markers can be overlapped and thus the objects would not be augmented. To solve this problem, a circle having the longest radius needs to be created from a focal point of a marker to be copied, so that no object is copied within the confines of the circle. In this paper, software-based sensing technology for multiple object detection and loading using PPHT has been developed and overlapping marker control according to multiple object control has been studied using the Bresenham and Mean Shift algorithms.
8. A Study on Software-based Sensing Technology for Multiple Object Control in AR Video
Seoksoo Kim
2010-11-01
Full Text Available Researches on Augmented Reality (AR have recently received attention. With these, the Machine-to-Machine (M2M market has started to be active and there are numerous efforts to apply this to real life in all sectors of society. To date, the M2M market has applied the existing marker-based AR technology in entertainment, business and other industries. With the existing marker-based AR technology, a designated object can only be loaded on the screen from one marker and a marker has to be added to load on the screen the same object again. This situation creates a problem where the relevant marker should be extracted and printed in screen so that loading of the multiple objects is enabled. However, since the distance between markers will not be measured in the process of detecting and copying markers, the markers can be overlapped and thus the objects would not be augmented. To solve this problem, a circle having the longest radius needs to be created from a focal point of a marker to be copied, so that no object is copied within the confines of the circle. In this paper, software-based sensing technology for multiple object detection and loading using PPHT has been developed and overlapping marker control according to multiple object control has been studied using the Bresenham and Mean Shift algorithms.
9. Simulation of neutron multiplicity measurements using Geant4. Open source software for nuclear arms control
Kuett, Moritz
2016-07-07
Nuclear arms control, including nuclear safeguards and verification technologies for nuclear disarmament typically use software as part of many different technological applications. This thesis proposes to use three open source criteria for such software, allowing users and developers to have free access to a program, have access to the full source code and be able to publish modifications for the program. This proposition is presented and analyzed in detail, together with the description of the development of ''Open Neutron Multiplicity Simulation'', an open source software tool to simulate neutron multiplicity measurements. The description includes physical background of the method, details of the developed program and a comprehensive set of validation calculations.
10. A new adaptive control scheme based on the interacting multiple model (IMM) estimation
Afshari, Hamed H.; Al-Ani, Dhafar; Habibi, Saeid
2016-01-01
In this paper, an Interacting multiple model (IMM) adaptive estimation approach is incorporated to design an optimal adaptive control law for stabilizing an Unmanned vehicle. Due to variations of the forward velocity of the Unmanned vehicle, its aerodynamic derivatives are constantly changing. In order to stabilize the unmanned vehicle and achieve the control objectives for in-flight conditions, one seeks for an adaptive control strategy that can adjust itself to varying flight conditions. In this context, a bank of linear models is used to describe the vehicle dynamics in different operating modes. Each operating mode represents a particular dynamic with a different forward velocity. These models are then used within an IMM filter containing a bank of Kalman filters (KF) in a parallel operating mechanism. To regulate and stabilize the vehicle, a Linear quadratic regulator (LQR) law is designed and implemented for each mode. The IMM structure determines the particular mode based on the stored models and in-flight input-output measurements. The LQR controller also provides a set of controllers; each corresponds to a particular flight mode and minimizes the tracking error. Finally, the ultimate control law is obtained as a weighted summation of all individual controllers whereas weights are obtained using mode probabilities of each operating mode.
11. Reserve-building activities in multiple sclerosis patients and healthy controls: a descriptive study.
Schwartz, Carolyn E; Ayandeh, Armon; Ramanathan, Murali; Benedict, Ralph; Dwyer, Michael G; Weinstock-Guttman, Bianca; Zivadinov, Robert
2015-08-12
Cognitive reserve has been implicated as a possible protective factor in multiple sclerosis (MS) but to date no study has compared reserve-building activities across disease course or to healthy controls. This study aims to describe differences in reserve-building activities across the MS disease course and healthy controls. Secondary analysis of a cross-sectional cohort study that included 276 healthy controls, and subjects with clinically isolated syndrome (CIS; n = 67), relapsing-remitting MS (RRMS; n = 358) and secondary progressive MS (PMS; n = 109). Past reserve-building activities were operationalized as occupational attainment and education. Current activities comprised 6 strenuous and 6 non-strenuous activities, including 5 reserve-building activities and television-watching. Multivariate Analysis of Variance models examined group differences in past and current activities, after adjusting for covariates. There were group differences in past and current reserve-building activities. SPMS patients had lower past reserve-building activities than healthy controls. All forms of MS engaged in fewer strenuous current reserve-building pursuits than healthy controls. RRMS read less than healthy controls. SPMS engaged in fewer job-related non-strenuous activities. All MS groups watched more television than healthy controls. MS patients show significantly fewer past and present reserve-building activities. Although it is difficult to establish causality without future prospective studies, lifestyle-modifying interventions should prioritize expanding MS patients' repertoire of strenuous and non-strenuous activities.
12. Multiple-Input Subject-Specific Modeling of Plasma Glucose Concentration for Feedforward Control.
Kotz, Kaylee; Cinar, Ali; Mei, Yong; Roggendorf, Amy; Littlejohn, Elizabeth; Quinn, Laurie; Rollins, Derrick K
2014-11-26
The ability to accurately develop subject-specific, input causation models, for blood glucose concentration (BGC) for large input sets can have a significant impact on tightening control for insulin dependent diabetes. More specifically, for Type 1 diabetics (T1Ds), it can lead to an effective artificial pancreas (i.e., an automatic control system that delivers exogenous insulin) under extreme changes in critical disturbances. These disturbances include food consumption, activity variations, and physiological stress changes. Thus, this paper presents a free-living, outpatient, multiple-input, modeling method for BGC with strong causation attributes that is stable and guards against overfitting to provide an effective modeling approach for feedforward control (FFC). This approach is a Wiener block-oriented methodology, which has unique attributes for meeting critical requirements for effective, long-term, FFC.
13. Magic Ring: A Finger-Worn Device for Multiple Appliances Control Using Static Finger Gestures
Tongjun Huang
2012-05-01
Full Text Available An ultimate goal for Ubiquitous Computing is to enable people to interact with the surrounding electrical devices using their habitual body gestures as they communicate with each other. The feasibility of such an idea is demonstrated through a wearable gestural device named Magic Ring (MR, which is an original compact wireless sensing mote in a ring shape that can recognize various finger gestures. A scenario of wireless multiple appliances control is selected as a case study to evaluate the usability of such a gestural interface. Experiments comparing the MR and a Remote Controller (RC were performed to evaluate the usability. From the results, only with 10 minutes practice, the proposed paradigm of gestural-based control can achieve a performance of completing about six tasks per minute, which is in the same level of the RC-based method.
14. The control system for the multiple-pellet injector on the Joint European Torus
Baylor, L.R.; Jernigan, T.C.; Stewart, K.A.
1989-01-01
A stand-alone control and data acquisition system for the Oak Ridge National Laboratory (ORNL) multiple-pellet injector installed on the Joint European Torus (JET) has been designed and installed with the injector. This system, which is based on a MicroVAX II computer and a programmable logic controller (PLC), is an upgrade of previous systems designed for ORNL pellet injectors installed on other fusion experiments. The primary control system upgrades are in the user interface, in the automation of sequential injector operation, and in the analysis of the transient data acquired for each pellet fired. The system is integrated into the JET CODAS environment through CAMAC communications modules with customized communications software. Routine operation of the injector is automated and requires no operator intervention. Details of the hardware and software design and the operation of the system are presented in this paper. 4 refs., 3 figs
15. Improving information retrieval with multiple health terminologies in a quality-controlled gateway.
Soualmia, Lina F; Sakji, Saoussen; Letord, Catherine; Rollin, Laetitia; Massari, Philippe; Darmoni, Stéfan J
2013-01-01
The Catalog and Index of French-language Health Internet resources (CISMeF) is a quality-controlled health gateway, primarily for Web resources in French (n=89,751). Recently, we achieved a major improvement in the structure of the catalogue by setting-up multiple terminologies, based on twelve health terminologies available in French, to overcome the potential weakness of the MeSH thesaurus, which is the main and pivotal terminology we use for indexing and retrieval since 1995. The main aim of this study was to estimate the added-value of exploiting several terminologies and their semantic relationships to improve Web resource indexing and retrieval in CISMeF, in order to provide additional health resources which meet the users' expectations. Twelve terminologies were integrated into the CISMeF information system to set up multiple-terminologies indexing and retrieval. The same sets of thirty queries were run: (i) by exploiting the hierarchical structure of the MeSH, and (ii) by exploiting the additional twelve terminologies and their semantic links. The two search modes were evaluated and compared. The overall coverage of the multiple-terminologies search mode was improved by comparison to the coverage of using the MeSH (16,283 vs. 14,159) (+15%). These additional findings were estimated at 56.6% relevant results, 24.7% intermediate results and 18.7% irrelevant. The multiple-terminologies approach improved information retrieval. These results suggest that integrating additional health terminologies was able to improve recall. Since performing the study, 21 other terminologies have been added which should enable us to make broader studies in multiple-terminologies information retrieval.
16. Analysis of the genetic phylogeny of multifocal prostate cancer identifies multiple independent clonal expansions in neoplastic and morphologically normal prostate tissue.
Cooper, Colin S; Eeles, Rosalind; Wedge, David C; Van Loo, Peter; Gundem, Gunes; Alexandrov, Ludmil B; Kremeyer, Barbara; Butler, Adam; Lynch, Andrew G; Camacho, Niedzica; Massie, Charlie E; Kay, Jonathan; Luxton, Hayley J; Edwards, Sandra; Kote-Jarai, ZSofia; Dennis, Nening; Merson, Sue; Leongamornlert, Daniel; Zamora, Jorge; Corbishley, Cathy; Thomas, Sarah; Nik-Zainal, Serena; O'Meara, Sarah; Matthews, Lucy; Clark, Jeremy; Hurst, Rachel; Mithen, Richard; Bristow, Robert G; Boutros, Paul C; Fraser, Michael; Cooke, Susanna; Raine, Keiran; Jones, David; Menzies, Andrew; Stebbings, Lucy; Hinton, Jon; Teague, Jon; McLaren, Stuart; Mudie, Laura; Hardy, Claire; Anderson, Elizabeth; Joseph, Olivia; Goody, Victoria; Robinson, Ben; Maddison, Mark; Gamble, Stephen; Greenman, Christopher; Berney, Dan; Hazell, Steven; Livni, Naomi; Fisher, Cyril; Ogden, Christopher; Kumar, Pardeep; Thompson, Alan; Woodhouse, Christopher; Nicol, David; Mayer, Erik; Dudderidge, Tim; Shah, Nimish C; Gnanapragasam, Vincent; Voet, Thierry; Campbell, Peter; Futreal, Andrew; Easton, Douglas; Warren, Anne Y; Foster, Christopher S; Stratton, Michael R; Whitaker, Hayley C; McDermott, Ultan; Brewer, Daniel S; Neal, David E
2015-04-01
Genome-wide DNA sequencing was used to decrypt the phylogeny of multiple samples from distinct areas of cancer and morphologically normal tissue taken from the prostates of three men. Mutations were present at high levels in morphologically normal tissue distant from the cancer, reflecting clonal expansions, and the underlying mutational processes at work in morphologically normal tissue were also at work in cancer. Our observations demonstrate the existence of ongoing abnormal mutational processes, consistent with field effects, underlying carcinogenesis. This mechanism gives rise to extensive branching evolution and cancer clone mixing, as exemplified by the coexistence of multiple cancer lineages harboring distinct ERG fusions within a single cancer nodule. Subsets of mutations were shared either by morphologically normal and malignant tissues or between different ERG lineages, indicating earlier or separate clonal cell expansions. Our observations inform on the origin of multifocal disease and have implications for prostate cancer therapy in individual cases.
17. Management Control in Major Brazilian Multiple Banks: the Impact of Internationalization and Convergence of Accounting Standards on the Control Systems
João Carlos Damasceno Reis
2014-08-01
Full Text Available This study verifies the impact caused by the processes of globalization and convergence to international accounting standards on the managerial control systems of the largest multiple banks that operate in Brazil. The study was exploratory in nature, with the use of the case study method and the application of questionnaires containing mostly open questions to upper tier executives of four major Brazilian banks. The analysis showed that globalization has resulted in improved control systems and widespread use of information technology. It was also found that the convergence to international accounting standards occurred properly, thanks to the steps taken by the Central Bank that aimed at an agile updating of the Brazilian accounting standards laid down for banks operating in Brazil, in line with international standards. In general, the researched banks did not report a significant impact of convergence to the IFRS on their management control systems; adherence to the international accounting standards has had more significant impacts on information systems, especially regarding the new reporting and transparency standards, rather than on management controls. This result signals that the management control systems of the four banks in the sample are in line with Anthony (1965’s vision, that is, that flexibility to adapt to every change in the external environment might actually increase risks of failure.
18. An imprinted non-coding genomic cluster at 14q32 defines clinically relevant molecular subtypes in osteosarcoma across multiple independent datasets
Hill, Katherine E.; Kelly, Andrew D.; Kuijjer, Marieke L.; Barry, William; Rattani, Ahmed; Garbutt, Cassandra C.; Kissick, Haydn; Janeway, Katherine; Perez-Atayde, Antonio; Goldsmith, Jeffrey; Gebhardt, Mark C.; Arredouani, Mohamed S.; Cote, Greg; Hornicek, Francis; Choy, Edwin
2017-01-01
Background: A microRNA (miRNA) collection on the imprinted 14q32 MEG3 region has been associated with outcome in osteosarcoma. We assessed the clinical utility of this miRNA set and their association with methylation status. Methods: We integrated coding and non-coding RNA data from three independent annotated clinical osteosarcoma cohorts (n = 65, n = 27, and n = 25) and miRNA and methylation data from one in vitro (19 cell lines) and one clinical (NCI Therapeutically Applicable Research to ...
19. Finite-time tracking control for multiple non-holonomic mobile robots based on visual servoing
Ou, Meiying; Li, Shihua; Wang, Chaoli
2013-12-01
This paper investigates finite-time tracking control problem of multiple non-holonomic mobile robots via visual servoing. It is assumed that the pinhole camera is fixed to the ceiling, and camera parameters are unknown. The desired reference trajectory is represented by a virtual leader whose states are available to only a subset of the followers, and the followers have only interaction. First, the camera-objective visual kinematic model is introduced by utilising the pinhole camera model for each mobile robot. Second, a unified tracking error system between camera-objective visual servoing model and desired reference trajectory is introduced. Third, based on the neighbour rule and by using finite-time control method, continuous distributed cooperative finite-time tracking control laws are designed for each mobile robot with unknown camera parameters, where the communication topology among the multiple mobile robots is assumed to be a directed graph. Rigorous proof shows that the group of mobile robots converges to the desired reference trajectory in finite time. Simulation example illustrates the effectiveness of our method.
20. Deletion variant near ZNF389 is associated with control of ovine lentivirus in multiple sheep flocks
White, S N; Mousel, M R; Reynolds, J O; Herrmann-Hoesing, L M; Knowles, D P
2014-01-01
Ovine lentivirus (OvLV) is a macrophage-tropic lentivirus found in many countries that causes interstitial pneumonia, mastitis, arthritis and cachexia in sheep. There is no preventive vaccine and no cure, but breed differences suggest marker-assisted selective breeding might improve odds of infection and control of OvLV post-infection. Although variants in TMEM154 have consistent association with odds of infection, no variant in any gene has been associated with host control of OvLV post-infection in multiple animal sets. Proviral concentration is a live-animal diagnostic measure of OvLV control post-infection related to severity of OvLV-induced lesions. A recent genome-wide association study identified a region including four zinc finger genes associated with proviral concentration in one Rambouillet flock. To refine this region, we tested additional variants and identified a small insertion/deletion variant near ZNF389 that showed consistent association with proviral concentration in three animal sets (P sheep from multiple locations and management conditions. Strikingly, one flock had exceptionally high prevalence (>87%, including yearlings) and mean proviral concentration (>950 copies/μg), possibly due to needle sharing. The best estimate of proviral concentration by genotype, obtained from all 1310 OvLV-positive animals tested, showed insertion homozygotes had less than half the proviral concentration of other genotypes (P sheep flocks. PMID:24303974
1. Large Display Interaction via Multiple Acceleration Curves and Multifinger Pointer Control
Andrey Esakia
2014-01-01
Full Text Available Large high-resolution displays combine high pixel density with ample physical dimensions. The combination of these factors creates a multiscale workspace where interactive targeting of on-screen objects requires both high speed for distant targets and high accuracy for small targets. Modern operating systems support implicit dynamic control-display gain adjustment (i.e., a pointer acceleration curve that helps to maintain both speed and accuracy. However, large high-resolution displays require a broader range of control-display gains than a single acceleration curve can usably enable. Some interaction techniques attempt to solve the problem by utilizing multiple explicit modes of interaction, where different modes provide different levels of pointer precision. Here, we investigate the alternative hypothesis of using a single mode of interaction for continuous pointing that enables both (1 standard implicit granularity control via an acceleration curve and (2 explicit switching between multiple acceleration curves in an efficient and dynamic way. We evaluate a sample solution that augments standard touchpad accelerated pointer manipulation with multitouch capability, where the choice of acceleration curve dynamically changes depending on the number of fingers in contact with the touchpad. Specifically, users can dynamically switch among three different acceleration curves by using one, two, or three fingers on the touchpad.
2. High power multiple wavelength diode laser stack for DPSSL application without temperature control
Hou, Dong; Yin, Xia; Wang, Jingwei; Chen, Shi; Zhan, Yun; Li, Xiaoning; Fan, Yingmin; Liu, Xingsheng
2018-02-01
High power diode laser stack is widely used in pumping solid-state laser for years. Normally an integrated temperature control module is required for stabilizing the output power of solid-state laser, as the output power of the solid-state laser highly depends on the emission wavelength and the wavelength shift of diode lasers according to the temperature changes. However the temperature control module is inconvenient for this application, due to its large dimension, high electric power consumption and extra adding a complicated controlling system. Furthermore, it takes dozens of seconds to stabilize the output power when the laser system is turned on. In this work, a compact hard soldered high power conduction cooled diode laser stack with multiple wavelengths is developed for stabilizing the output power of solid-state laser in a certain temperature range. The stack consists of 5 laser bars with the pitch of 0.43mm. The peak output power of each bar in the diode laser stack reaches as much as 557W and the combined lasing wavelength spectrum profile spans 15nm. The solidstate laser, structured with multiple wavelength diode laser stacks, allows the ambient temperature change of 65°C without suddenly degrading the optical performance.
3. A multiple objective test assembly approach for exposure control problems in Computerized Adaptive Testing
Theo J.H.M. Eggen
2010-01-01
Full Text Available Overexposure and underexposure of items in the bank are serious problems in operational computerized adaptive testing (CAT systems. These exposure problems might result in item compromise, or point at a waste of investments. The exposure control problem can be viewed as a test assembly problem with multiple objectives. Information in the test has to be maximized, item compromise has to be minimized, and pool usage has to be optimized. In this paper, a multiple objectives method is developed to deal with both types of exposure problems. In this method, exposure control parameters based on observed exposure rates are implemented as weights for the information in the item selection procedure. The method does not need time consuming simulation studies, and it can be implemented conditional on ability level. The method is compared with Sympson Hetter method for exposure control, with the Progressive method and with alphastratified testing. The results show that the method is successful in dealing with both kinds of exposure problems.
4. Design of clinical trials involving multiple hypothesis tests with a common control.
Schou, I Manjula; Marschner, Ian C
2017-07-01
Randomized clinical trials comparing several treatments to a common control are often reported in the medical literature. For example, multiple experimental treatments may be compared with placebo, or in combination therapy trials, a combination therapy may be compared with each of its constituent monotherapies. Such trials are typically designed using a balanced approach in which equal numbers of individuals are randomized to each arm, however, this can result in an inefficient use of resources. We provide a unified framework and new theoretical results for optimal design of such single-control multiple-comparator studies. We consider variance optimal designs based on D-, A-, and E-optimality criteria, using a general model that allows for heteroscedasticity and a range of effect measures that include both continuous and binary outcomes. We demonstrate the sensitivity of these designs to the type of optimality criterion by showing that the optimal allocation ratios are systematically ordered according to the optimality criterion. Given this sensitivity to the optimality criterion, we argue that power optimality is a more suitable approach when designing clinical trials where testing is the objective. Weighted variance optimal designs are also discussed, which, like power optimal designs, allow the treatment difference to play a major role in determining allocation ratios. We illustrate our methods using two real clinical trial examples taken from the medical literature. Some recommendations on the use of optimal designs in single-control multiple-comparator trials are also provided. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
5. Massage therapy and exercise therapy in patients with multiple sclerosis: a randomized controlled pilot study.
Negahban, Hossein; Rezaie, Solmaz; Goharpey, Shahin
2013-12-01
The primary aim was to investigate the comparative effects of massage therapy and exercise therapy on patients with multiple sclerosis. The secondary aim was to investigate whether combination of both massage and exercise has an additive effect. Randomized controlled pilot trial with repeated measurements and blinded assessments. Local Multiple Sclerosis Society. A total of 48 patients with multiple sclerosis were randomly assigned to four equal subgroups labelled as massage therapy, exercise therapy, combined massage-exercise therapy and control group. The treatment group received 15 sessions of supervised intervention for five weeks. The massage therapy group received a standard Swedish massage. The exercise therapy group was given a combined set of strength, stretch, endurance and balance exercises. Patients in the massage-exercise therapy received a combined set of massage and exercise treatments. Patients in the control group were asked to continue their standard medical care. Pain, fatigue, spasticity, balance, gait and quality of life were assessed before and after intervention. Massage therapy resulted in significantly larger improvement in pain reduction (mean change 2.75 points, P = 0.001), dynamic balance (mean change, 3.69 seconds, P = 0.009) and walking speed (mean change, 7.84 seconds, P = 0.007) than exercise therapy. Patients involved in the combined massage-exercise therapy showed significantly larger improvement in pain reduction than those in the exercise therapy (mean change, 1.67 points, P = 0.001). Massage therapy could be more effective than exercise therapy. Moreover, the combination of massage and exercise therapy may be a little more effective than exercise therapy alone.
6. Traffic Management by Using Admission Control Methods in Multiple Node IMS Network
Filip Chamraz
2016-01-01
Full Text Available The paper deals with Admission Control methods (AC as a possible solution for traffic management in IMS networks (IP Multimedia Subsystem - from the point of view of an efficient redistribution of the available network resources and keeping the parameters of Quality of Service (QoS. The paper specifically aims at the selection of the most appropriate method for the specific type of traffic and traffic management concept using AC methods on multiple nodes. The potential benefit and disadvantage of the used solution is evaluated.
7. Tunable arbitrary unitary transformer based on multiple sections of multicore fibers with phase control.
Zhou, Junhe; Wu, Jianjie; Hu, Qinsong
2018-02-05
In this paper, we propose a novel tunable unitary transformer, which can achieve arbitrary discrete unitary transforms. The unitary transformer is composed of multiple sections of multi-core fibers with closely aligned coupled cores. Phase shifters are inserted before and after the sections to control the phases of the waves in the cores. A simple algorithm is proposed to find the optimal phase setup for the phase shifters to realize the desired unitary transforms. The proposed device is fiber based and is particularly suitable for the mode division multiplexing systems. A tunable mode MUX/DEMUX for a three-mode fiber is designed based on the proposed structure.
8. Multiple shooting applied to robust reservoir control optimization including output constraints on coherent risk measures
Codas, Andrés; Hanssen, Kristian G.; Foss, Bjarne
2017-01-01
The production life of oil reservoirs starts under significant uncertainty regarding the actual economical return of the recovery process due to the lack of oil field data. Consequently, investors and operators make management decisions based on a limited and uncertain description of the reservoir....... In this work, we propose a new formulation for robust optimization of reservoir well controls. It is inspired by the multiple shooting (MS) method which permits a broad range of parallelization opportunities and output constraint handling. This formulation exploits coherent risk measures, a concept...
9. Vascular comorbidities in multiple sclerosis
Thormann, Anja; Magyari, Melinda; Koch-Henriksen, Nils
2016-01-01
To investigate the occurrence of vascular comorbidities before and after the clinical onset of multiple sclerosis. In this combined case-control and cohort study, all Danish born citizens with onset of multiple sclerosis 1980-2005 were identified from the Danish Multiple Sclerosis Registry...... and randomly matched with controls regarding year of birth, gender, and municipality on January 1st in the year of multiple sclerosis (MS) onset (index date). Individual-level information on comorbidities was obtained from several independent nationwide registries and linked to the study population by unique...
10. Multiple model predictive control for optimal drug administration of mixed immunotherapy and chemotherapy of tumours.
Sharifi, N; Ozgoli, S; Ramezani, A
2017-06-01
Mixed immunotherapy and chemotherapy of tumours is one of the most efficient ways to improve cancer treatment strategies. However, it is important to 'design' an effective treatment programme which can optimize the ways of combining immunotherapy and chemotherapy to diminish their imminent side effects. Control engineering techniques could be used for this. The method of multiple model predictive controller (MMPC) is applied to the modified Stepanova model to induce the best combination of drugs scheduling under a better health criteria profile. The proposed MMPC is a feedback scheme that can perform global optimization for both tumour volume and immune competent cell density by performing multiple constraints. Although current studies usually assume that immunotherapy has no side effect, this paper presents a new method of mixed drug administration by employing MMPC, which implements several constraints for chemotherapy and immunotherapy by considering both drug toxicity and autoimmune. With designed controller we need maximum 57% and 28% of full dosage of drugs for chemotherapy and immunotherapy in some instances, respectively. Therefore, through the proposed controller less dosage of drugs are needed, which contribute to suitable results with a perceptible reduction in medicine side effects. It is observed that in the presence of MMPC, the amount of required drugs is minimized, while the tumour volume is reduced. The efficiency of the presented method has been illustrated through simulations, as the system from an initial condition in the malignant region of the state space (macroscopic tumour volume) transfers into the benign region (microscopic tumour volume) in which the immune system can control tumour growth. Copyright © 2017 Elsevier B.V. All rights reserved.
11. Analysis of the immune system of multiple myeloma patients achieving long-term disease control by multidimensional flow cytometry
Pessoa de Magalhães, Roberto J.; Vidriales, María-Belén; Paiva, Bruno; Fernandez-Gimenez, Carlos; García-Sanz, Ramón; Mateos, Maria-Victoria; Gutierrez, Norma C.; Lecrevisse, Quentin; Blanco, Juan F; Hernández, Jose; de las Heras, Natalia; Martinez-Lopez, Joaquin; Roig, Monica; Costa, Elaine Sobral; Ocio, Enrique M.; Perez-Andres, Martin; Maiolino, Angelo; Nucci, Marcio; De La Rubia, Javier; Lahuerta, Juan-Jose; San-Miguel, Jesús F.; Orfao, Alberto
2013-01-01
Multiple myeloma remains largely incurable. However, a few patients experience more than 10 years of relapse-free survival and can be considered as operationally cured. Interestingly, long-term disease control in multiple myeloma is not restricted to patients with a complete response, since some patients revert to having a profile of monoclonal gammopathy of undetermined significance. We compared the distribution of multiple compartments of lymphocytes and dendritic cells in the bone marrow and peripheral blood of multiple myeloma patients with long-term disease control (n=28), patients with newly diagnosed monoclonal gammopathy of undetermined significance (n=23), patients with symptomatic multiple myeloma (n=23), and age-matched healthy adults (n=10). Similarly to the patients with monoclonal gammopathy of undetermined significance and symptomatic multiple myeloma, patients with long-term disease control showed an expansion of cytotoxic CD8+ T cells and natural killer cells. However, the numbers of bone marrow T-regulatory cells were lower in patients with long-term disease control than in those with symptomatic multiple myeloma. It is noteworthy that B cells were depleted in patients with monoclonal gammopathy of undetermined significance and in those with symptomatic multiple myeloma, but recovered in both the bone marrow and peripheral blood of patients with long-term disease control, due to an increase in normal bone marrow B-cell precursors and plasma cells, as well as pre-germinal center peripheral blood B cells. The number of bone marrow dendritic cells and tissue macrophages differed significantly between patients with long-term disease control and those with symptomatic multiple myeloma, with a trend to cell count recovering in the former group of patients towards levels similar to those found in healthy adults. In summary, our results indicate that multiple myeloma patients with long-term disease control have a constellation of unique immune changes
12. Coordination of networked systems on digraphs with multiple leaders via pinning control
Chen, Gang; Lewis, Frank L.
2012-02-01
It is well known that achieving consensus among a group of multi-vehicle systems by local distributed control is feasible if and only if all nodes in the communication digraph are reachable from a single (root) node. In this article, we take into account a more general case that the communication digraph of the networked multi-vehicle systems is weakly connected and has two or more zero-in-degree and strongly connected subgraphs, i.e. there are two or more leader groups. Based on the pinning control strategy, the feasibility problem of achieving second-order controlled consensus is studied. At first, a necessary and sufficient condition is given when the topology is fixed. Then the method to design the controller and the rule to choose the pinned vehicles are discussed. The proposed approach allows us to extend several existing results for undirected graphs to directed balanced graphs. A sufficient condition is proposed in the case where the coupling topology is variable. As an illustrative example, a second-order controlled consensus scheme is applied to coordinate the movement of networked multiple mobile robots.
13. Flocking Control of Multiple Mobile Agents with the Rules of Avoiding Collision
Hongtao Zhou
2015-01-01
Full Text Available This paper investigates the flocking and the coordinative control problems of multiple mobile agents with the rules of avoiding collision. We propose a set of control laws using hysteresis in adding new links and applying new potential function to guarantee that the fragmentation of the network can be avoided, under which all agents approach a common velocity vector, and asymptotically converge to a fixed value of interagent distances and collisions between agents can be avoided throughout the motion. Furthermore, we extend the flocking algorithm to solve the flocking situation of the group with a virtual leader agent. The laws can make all agents asymptotically approach the virtual leader and collisions can be avoided between agents in the motion evolution. Finally, some numerical simulations are showed to illustrate the theoretical results.
14. Control of hospital endemicity of multiple-drug-resistant Acinetobacter baumannii ST457 with directly observed hand hygiene.
Cheng, V C C; Chen, J H K; Poon, R W S; Lee, W M; So, S Y C; Wong, S C Y; Chau, P H; Yip, C C Y; Wong, S S Y; Chan, J F W; Hung, I F N; Ho, P L; Yuen, K Y
2015-04-01
An increasing endemicity of multiple-drug-resistant Acinetobacter baumannii (MRAB) ST457 was noted in Hong Kong. The epidemiology, risk factors, and infection control measures to prevent nosocomial transmission of this epidemic clone were analyzed. A total of 5,058 patients cultured positive with A. baumannii between 1 January 2004 and 30 June 2014 were included, of which 297 (5.9 %) had bacteremia. The first case of MRAB bacteremia emerged in 2009, with an incidence that increased from 0.27 (one case) in 2009 to 1.86 (14 cases) per 100,000 patient-days in 2013 (p hand hygiene in conscious patients immediately before receiving meals and medications in July 2013, the incidence of MRAB bacteremia reduced from its peak to 0.77 (one case) per 100,000 patient-days in the first 6 months of 2014 (p < 0.001). Patients from long-term care facilities for the elderly [odds ratio (OR) 18.6, confidence interval (CI) 2.1-162.4, p = 0.008] and history of carbapenem (OR 7.0, CI 1.7-28.0, p = 0.006) and beta-lactam/beta-lactamase use (OR 5.6, CI 1.1-28.7, p = 0.038) 90 days prior to admission were independent risk factors for MRAB bacteremia by logistic regression when compared with carbapenem-susceptible A. baumannii bacteremia.
15. Improvements in cognition, quality of life, and physical performance with clinical Pilates in multiple sclerosis: a randomized controlled trial
K???k, Fadime; Kara, Bilge; Poyraz, Esra ?o?kuner; ?diman, Egemen
2016-01-01
[Purpose] The aim of this study was to determine the effects of clinical Pilates in multiple sclerosis patients. [Subjects and Methods] Twenty multiple sclerosis patients were enrolled in this study. The participants were divided into two groups as the clinical Pilates and control groups. Cognition (Multiple Sclerosis Functional Composite), balance (Berg Balance Scale), physical performance (timed performance tests, Timed up and go test), tiredness (Modified Fatigue Impact scale), depression ...
16. Channel selection for simultaneous and proportional myoelectric prosthesis control of multiple degrees-of-freedom
Hwang, Han-Jeong; Hahne, Janne Mathias; Müller, Klaus-Robert
2014-10-01
Objective. Recent studies have shown the possibility of simultaneous and proportional control of electrically powered upper-limb prostheses, but there has been little investigation on optimal channel selection. The objective of this study is to find a robust channel selection method and the channel subsets most suitable for simultaneous and proportional myoelectric prosthesis control of multiple degrees-of-freedom (DoFs). Approach. Ten able-bodied subjects and one person with congenital upper-limb deficiency took part in this study, and performed wrist movements with various combinations of two DoFs (flexion/extension and radial/ulnar deviation). During the experiment, high density electromyographic (EMG) signals and the actual wrist angles were recorded with an 8 × 24 electrode array and a motion tracking system, respectively. The wrist angles were estimated from EMG features with ridge regression using the subsets of channels chosen by three different channel selection methods: (1) least absolute shrinkage and selection operator (LASSO), (2) sequential feature selection (SFS), and (3) uniform selection (UNI). Main results. SFS generally showed higher estimation accuracy than LASSO and UNI, but LASSO always outperformed SFS in terms of robustness, such as noise addition, channel shift and training data reduction. It was also confirmed that about 95% of the original performance obtained using all channels can be retained with only 12 bipolar channels individually selected by LASSO and SFS. Significance. From the analysis results, it can be concluded that LASSO is a promising channel selection method for accurate simultaneous and proportional prosthesis control. We expect that our results will provide a useful guideline to select optimal channel subsets when developing clinical myoelectric prosthesis control systems based on continuous movements with multiple DoFs.
17. A full scope nuclear power plant simulator for multiple reactor types with virtual control panels
Yonezawa, Hisanori; Ueda, Hiroki; Kato, Takahisa
2017-01-01
This paper summarizes a full scope nuclear power plant simulator for multiple reactor types with virtual control panels which Toshiba developed and delivered. After the Fukushima DAIICHI nuclear power plants accident, it is required that all the people who are engaged in the design, manufacturing, operation, maintenance, management and regulation for the nuclear power plant should learn the wide and deep knowledge about the nuclear power plant design including the severe accident. For this purpose, the training with a full scope simulator is one of the most suitable ways. However the existing full scope simulators which are consist of the control panels replica of the referenced plants are costly and they are hard to remodel to fit to the real plant of the latest condition. That's why Toshiba developed and delivered the new concept simulator system which covers multiple referenced plants even though they have different design like BWR and PWR. The control panels of the simulator are made by combining 69 large Liquid Crystal Display (LCD) panels with touch screen instead of a control panel replica of referenced plant. The screen size of the each panel is 42 inches and 3 displays are arranged in tandem for one unit and 23 units are connected together. Each panel displays switches, indicators, recorders and lamps with the Computer Graphics (CG) and trainees operate them with touch operations. The simulator includes a BWR and a PWR simulator model, which enable trainees to learn the wide and deep knowledge about the nuclear power plant of BWR and PWR reactor types. (author)
18. Selective control of multiple ferroelectric switching pathways using a trailing flexoelectric field
Park, Sung Min; Wang, Bo; Das, Saikat; Chae, Seung Chul; Chung, Jin-Seok; Yoon, Jong-Gul; Chen, Long-Qing; Yang, Sang Mo; Noh, Tae Won
2018-05-01
Flexoelectricity is an electromechanical coupling between electrical polarization and a strain gradient1 that enables mechanical manipulation of polarization without applying an electrical bias2,3. Recently, flexoelectricity was directly demonstrated by mechanically switching the out-of-plane polarization of a uniaxial system with a scanning probe microscope tip3,4. However, the successful application of flexoelectricity in low-symmetry multiaxial ferroelectrics and therefore active manipulation of multiple domains via flexoelectricity have not yet been achieved. Here, we demonstrate that the symmetry-breaking flexoelectricity offers a powerful route for the selective control of multiple domain switching pathways in multiaxial ferroelectric materials. Specifically, we use a trailing flexoelectric field that is created by the motion of a mechanically loaded scanning probe microscope tip. By controlling the SPM scan direction, we can deterministically select either stable 71° ferroelastic switching or 180° ferroelectric switching in a multiferroic magnetoelectric BiFeO3 thin film. Phase-field simulations reveal that the amplified in-plane trailing flexoelectric field is essential for this domain engineering. Moreover, we show that mechanically switched domains have a good retention property. This work opens a new avenue for the deterministic selection of nanoscale ferroelectric domains in low-symmetry materials for non-volatile magnetoelectric devices and multilevel data storage.
19. $H^\\infty$ control of systems with multiple I/O delays via decomposition to adobe problems
Meinsma, Gjerrit; Mirkin, Leonid
In this paper, the standard (four-block) $H^\\infty$ control problem for systems with multiple input-output delays in the feedback loop is studied. The central idea is to see the multiple delay operator as a special series connection of elementary delay operators, called the adobe delay operators.
20. A real-time automated quality control of rain gauge data based on multiple sensors
qi, Y.; Zhang, J.
2013-12-01
Precipitation is one of the most important meteorological and hydrological variables. Automated rain gauge networks provide direct measurements of precipitation and have been used for numerous applications such as generating regional and national precipitation maps, calibrating remote sensing data, and validating hydrological and meteorological model predictions. Automated gauge observations are prone to a variety of error sources (instrument malfunction, transmission errors, format changes), and require careful quality controls (QC). Many previous gauge QC techniques were based on neighborhood checks within the gauge network itself and the effectiveness is dependent on gauge densities and precipitation regimes. The current study takes advantage of the multi-sensor data sources in the National Mosaic and Multi-Sensor QPE (NMQ/Q2) system and developes an automated gauge QC scheme based the consistency of radar hourly QPEs and gauge observations. Error characteristics of radar and gauge as a function of the radar sampling geometry, precipitation regimes, and the freezing level height are considered. The new scheme was evaluated by comparing an NMQ national gauge-based precipitation product with independent manual gauge observations. Twelve heavy rainfall events from different seasons and areas of the United States are selected for the evaluation, and the results show that the new NMQ product with QC'ed gauges has a more physically spatial distribution than the old product. And the new product agrees much better statistically with the independent gauges.
1. Fundamental Evaluation of Adaptation and Human Capabilities in a Condition Using a System to Give a User an Artificial Oculomotor Function to Control Directions of Both Eyes Independently
Fumio Mizuno
2011-10-01
Full Text Available To investigate flexible adaptation of visual system, we developed a system to provide a user an artificial oculomotor function to control directions of both eyes. The system named “Virtual Chameleon” consists of two CCD cameras independently controlled and a head-mounted display. The user can control each tracking directions of two cameras with sensors set to both hands so that the user can get independent arbitrary view fields for both eyes. We performed fundamental experiments to evaluate capability to evaluate adaptation to use of Virtual Chameleon and effects on the user's capabilities. Eleven healthy volunteers with normal and corrected-to-normal vision participated in the experiments. The experiments were tests to find out each position of targets put in both side of a subject. In the experiments, a condition using Virtual Chameleon and a condition without it was adopted. We obtained accuracy rates and time intervals to find out target positions as experimental results. The experiments showed all of volunteers became able to actively control independent visual axes and correctly understood two different views by using Virtual Chameleon, even though two independent view fields yielded binocular rivalry to volunteers and binocular rivalry reduced human capabilities compared to cases without Virtual Chameleon.
2. Testing single-grain quartz OSL methods using sediment samples with independent age control from the Bordes-Fitte rockshelter (Roches d'Abilly site, Central France)
Thomsen, Kristina Jørkov; Murray, Andrew Sean; Buylaert, Jan-Pieter
2016-01-01
We present quartz single-grain dose distributions for four well-bleached and unmixed sediment samples with independent age control (22–48 ka), from the archaeologically important Bordes-Fitte rockshelter at Roches d'Abilly, France. This site has previously been dated using 14C AMS dating and stan...
3. Optimal planning approaches with multiple impulses for rendezvous based on hybrid genetic algorithm and control method
JingRui Zhang
2015-03-01
Full Text Available In this article, we focus on safe and effective completion of a rendezvous and docking task by looking at planning approaches and control with fuel-optimal rendezvous for a target spacecraft running on a near-circular reference orbit. A variety of existent practical path constraints are considered, including the constraints of field of view, impulses, and passive safety. A rendezvous approach is calculated by using a hybrid genetic algorithm with those constraints. Furthermore, a control method of trajectory tracking is adopted to overcome the external disturbances. Based on Clohessy–Wiltshire equations, we first construct the mathematical model of optimal planning approaches of multiple impulses with path constraints. Second, we introduce the principle of hybrid genetic algorithm with both stronger global searching ability and local searching ability. We additionally explain the application of this algorithm in the problem of trajectory planning. Then, we give three-impulse simulation examples to acquire an optimal rendezvous trajectory with the path constraints presented in this article. The effectiveness and applicability of the tracking control method are verified with the optimal trajectory above as control objective through the numerical simulation.
4. Comparison of Personality Characteristics and Coping Strategies in Patients With Multiple Sclerosis and Control Group
2015-09-01
Full Text Available Background The present study aimed to investigate personality traits and coping strategies in patients with multiple sclerosis (MS who were admitted to Sina hospital compared with healthy individuals. Objectives The aim of the present study was to compare personality characteristics and coping strategies between patients with MS and healthy controls. Materials and Methods The study sample included 55 patients with MS and 57 matched healthy control individuals. The data were gathered via a demographic form, the ways of coping questionnaire, and the NEO five-factor inventory. The data were analyzed by multivariate analysis of variance (MANOVA, Pearson’s correlation coefficient, and logistic regression. Results No significant differences in personality characteristics were observed between patients and healthy controls (all P > 0.05. Only the coping strategy subscale of Distancing was significant between patients and healthy controls (P 0.05. Only the Neuroticism personality trait and the Distancing coping strategy were predictive of group membership (i.e., healthy or patient. Conclusions Our study suggests that the personality traits of patients with MS and healthy individuals are not significantly different. Patients with MS are likely to use the same coping strategies as healthy individuals, except in the subscale of Distancing.
5. Combined chemical (fluoranthene) and drought effects on Lumbricus rubellus demonstrate the applicability of the independent action model for multiple stressor assessment.
Long, Sara M; Reichenberg, Fredrik; Lister, Lindsay J; Hankard, Peter K; Townsend, Joanna; Mayer, Philipp; Wright, Julian; Holmstrup, Martin; Svendsen, Claus; Spurgeon, David J
2009-03-01
The combined effect of a chemical (fluoranthene) and a nonchemical stress (reduced soil moisture content) to the widely distributed earthworm Lumbricus rubellus were investigated in a laboratory study. Neither fluoranthene (up to 500 microg/g) nor low soil moisture (15% below optimal) had a significant effect on the survival of the exposed worms, but a significant effect on reproduction (cocoon production rate) was found for both stressors (p IA) model that is widely used in pharmacology and chemical mixture risk assessment. Fitting of the IA model provided a good description of the combined stressor data (accounting for 53.7% of total variation) and was the most parsimonious model describing joint effect (i.e., the description of the data was not improved by addition of further parameters accounting for synergism or antagonism). Thus, the independent action of the two responses was further supported by measurement of internal fluoranthene exposure. The chemical activity of fluoranthene in worm tissue was correlated only with soil fluoranthene concentration and not with soil moisture content. Taken together these results suggest that the IA model can help interpret the joint effects of chemical and nonchemical stressors. Such analyses should, however, be done with caution since the literature data set suggests that there may be cases where interactions between stressors result in joint effects that differ significantly from IA predictions.
6. Multiple signalling pathways redundantly control glucose transporter GLUT4 gene transcription in skeletal muscle
Murgia, Marta; Elbenhardt Jensen, Thomas; Cusinato, Marzia
2009-01-01
on pharmacological evidence. Here, we have used a more specific genetic approach to establish the relative role of the three pathways in fast and slow muscles. Plasmids coding for protein inhibitors of CaMKII or calcineurin were co-transfected in vivo with a GLUT4 enhancer-reporter construct either in normal mice...... or in mice expressing a dominant negative AMPK mutant. GLUT4 reporter activity was not inhibited in the slow soleus muscle by blocking either CaMKII or calcineurin alone, but was inhibited by blocking both pathways. GLUT4 reporter activity was likewise unchanged in the soleus of dnAMPK mice......, but was significantly reduce by incapacitation of either CaMKII or calcineurin in these mice. On the other hand, in the fast tibialis anterior muscle, calcineurin appears to exert a prominent role in the control of GLUT4 reporter activity, independent of CaMKII and AMPK. The results point to a muscle type...
7. Ultrasonographic evaluation of cerebral arterial and venous haemodynamics in multiple sclerosis: a case-control study.
Pasquale Marchione
Full Text Available OBJECTIVE: Although recent studies excluded an association between Chronic Cerebrospinal Venous Insufficiency and Multiple Sclerosis (MS, controversial results account for some cerebrovascular haemodynamic impairment suggesting a dysfunction of cerebral autoregulation mechanisms. The aim of this cross-sectional, case-control study is to evaluate cerebral arterial inflow and venous outflow by means of a non-invasive ultrasound procedure in Relapsing Remitting (RR, Primary Progressive (PP Multiple Sclerosis and age and sex-matched controls subjects. MATERIAL AND METHODS: All subjects underwent a complete extra-intracranial arterial and venous ultrasound assessment with a color-coded duplex sonography scanner and a transcranial doppler equipment, in both supine and sitting position by means of a tilting chair. Basal arterial and venous morphology and flow velocities, postural changes in mean flow velocities (MFV of middle cerebral arteries (MCA, differences between cerebral venous outflow (CVF in clinostatism and in the seated position (ΔCVF and non-invasive cerebral perfusion pressure (CPP were evaluated. RESULTS: 85 RR-MS, 83 PP-MS and 82 healthy controls were included. ΔCVF was negative in 45/85 (52.9% RR-MS, 63/83 (75.9% PP-MS (p = 0.01 and 11/82 (13.4% controls (p<0.001, while MFVs on both MCAs in sitting position were significantly reduced in RR-MS and PP-MS patients than in control, particularly in EDSS ≥ 5 subgroup (respectively, 42/50, 84% vs. 66/131, 50.3%, p<0.01 and 48.3 ± 2 cm/s vs. 54.6 ± 3 cm/s, p = 0.01. No significant differences in CPP were observed within and between groups. CONCLUSIONS: The quantitative evaluation of cerebral blood flow (CBF and CVF and their postural dependency may be related to a dysfunction of autonomic nervous system that seems to characterize more disabled MS patients. It's not clear whether the altered postural control of arterial inflow and venous outflow is a specific MS condition or simply an
8. Molecular evolution of multiple-level control of heme biosynthesis pathway in animal kingdom.
Tzou, Wen-Shyong; Chu, Ying; Lin, Tzung-Yi; Hu, Chin-Hwa; Pai, Tun-Wen; Liu, Hsin-Fu; Lin, Han-Jia; Cases, Ildeofonso; Rojas, Ana; Sanchez, Mayka; You, Zong-Ye; Hsu, Ming-Wei
2014-01-01
Adaptation of enzymes in a metabolic pathway can occur not only through changes in amino acid sequences but also through variations in transcriptional activation, mRNA splicing and mRNA translation. The heme biosynthesis pathway, a linear pathway comprised of eight consecutive enzymes in animals, provides researchers with ample information for multiple types of evolutionary analyses performed with respect to the position of each enzyme in the pathway. Through bioinformatics analysis, we found that the protein-coding sequences of all enzymes in this pathway are under strong purifying selection, from cnidarians to mammals. However, loose evolutionary constraints are observed for enzymes in which self-catalysis occurs. Through comparative genomics, we found that in animals, the first intron of the enzyme-encoding genes has been co-opted for transcriptional activation of the genes in this pathway. Organisms sense the cellular content of iron, and through iron-responsive elements in the 5' untranslated regions of mRNAs and the intron-exon boundary regions of pathway genes, translational inhibition and exon choice in enzymes may be enabled, respectively. Pathway product (heme)-mediated negative feedback control can affect the transport of pathway enzymes into the mitochondria as well as the ubiquitin-mediated stability of enzymes. Remarkably, the positions of these controls on pathway activity are not ubiquitous but are biased towards the enzymes in the upstream portion of the pathway. We revealed that multiple-level controls on the activity of the heme biosynthesis pathway depend on the linear depth of the enzymes in the pathway, indicating a new strategy for discovering the molecular constraints that shape the evolution of a metabolic pathway.
9. Sympathetic skin response in multiple sclerosis: a meta-analysis of case-control studies.
Margaritella, Nicolò; Mendozzi, Laura; Garegnani, Massimo; Gilardi, Elisabetta; Nemni, Raffaello; Pugnetti, Luigi
2018-01-01
The usefulness of sympathetic skin responses (SSR) in multiple sclerosis (MS) has been advocated by several studies in the last 20 years; however, due to a great heterogeneity of findings, a comprehensive meta-analysis of case-control studies is in order to pinpoint consistencies and investigate the causes of discrepancies. We searched MEDLINE, EMBASE and Cochrane databases for case-control studies comparing SSR absence frequency and latency between patients with MS and healthy controls. Thirteen eligible studies including 415 MS patients and 331 healthy controls were identified. The pooled analysis showed that SSR can be always obtained in healthy controls while 34% of patients had absent SSRs in at least one limb (95% CI 22-47%; p studies (I 2 = 90.3%). Patients' age explained 22% of the overall variability and positive correlations were found with Expanded Disability Status Scale and disease duration. The pooled mean difference of SSR latency showed a significant increase in patients on both upper (193 ms; 95% CI 120-270 ms) and lower (350 ms; 95% CI 190-510 ms) extremities. We tested the discriminatory value of SSR latency thresholds defined as the 95% confidence interval (CI) upper bound of the healthy controls, and validated the results on a new dataset. The lower limb threshold of 1.964 s produces the best results in terms of sensitivity 0.86, specificity 0.67, positive predicted value 0.75 and negative predicted value 0.80. Despite a considerable heterogeneity of findings, there is evidence that SSR is a useful tool in MS.
10. Neural-adaptive control of single-master-multiple-slaves teleoperation for coordinated multiple mobile manipulators with time-varying communication delays and input uncertainties.
Li, Zhijun; Su, Chun-Yi
2013-09-01
In this paper, adaptive neural network control is investigated for single-master-multiple-slaves teleoperation in consideration of time delays and input dead-zone uncertainties for multiple mobile manipulators carrying a common object in a cooperative manner. Firstly, concise dynamics of teleoperation systems consisting of a single master robot, multiple coordinated slave robots, and the object are developed in the task space. To handle asymmetric time-varying delays in communication channels and unknown asymmetric input dead zones, the nonlinear dynamics of the teleoperation system are transformed into two subsystems through feedback linearization: local master or slave dynamics including the unknown input dead zones and delayed dynamics for the purpose of synchronization. Then, a model reference neural network control strategy based on linear matrix inequalities (LMI) and adaptive techniques is proposed. The developed control approach ensures that the defined tracking errors converge to zero whereas the coordination internal force errors remain bounded and can be made arbitrarily small. Throughout this paper, stability analysis is performed via explicit Lyapunov techniques under specific LMI conditions. The proposed adaptive neural network control scheme is robust against motion disturbances, parametric uncertainties, time-varying delays, and input dead zones, which is validated by simulation studies.
11. Participant recruitment into a randomised controlled trial of exercise therapy for people with multiple sclerosis.
Carter, Anouska; Humphreys, Liam; Snowdon, Nicky; Sharrack, Basil; Daley, Amanda; Petty, Jane; Woodroofe, Nicola; Saxton, John
2015-10-15
The success of a clinical trial is often dependant on whether recruitment targets can be met in the required time frame. Despite an increase in research into the benefits of exercise in people with multiple sclerosis (PwMS), no trial has reported detailed data on effective recruitment strategies for large-scale randomised controlled trials. The main purpose of this report is to provide a detailed outline of recruitment strategies, rates and estimated costs in the Exercise Intervention for Multiple Sclerosis (ExIMS) trial to identify best practices for future trials involving multiple sclerosis (MS) patient recruitment. The ExIMS researchers recruited 120 PwMS to participate in a 12-week exercise intervention. Participants were randomly allocated to either exercise or usual-care control groups. Participants were sedentary, aged 18-65 years and had Expanded Disability Status Scale scores of 1.0-6.5. Recruitment strategies included attendance at MS outpatient clinics, consultant mail-out and trial awareness-raising activities. A total of 120 participants were recruited over the course of 34 months. To achieve this target, 369 potentially eligible and interested participants were identified. A total of 60 % of participants were recruited via MS clinics, 29.2 % from consultant mail-outs and 10.8 % through trial awareness. The randomisation yields were 33.2 %, 31.0 % and 68.4 % for MS clinic, consultant mail-outs and trial awareness strategies, respectively. The main reason for ineligibility was being too active (69.2 %), whilst for eligible participants the most common reason for non-participation was the need to travel to the study site (15.8 %). Recruitment via consultant mail-out was the most cost-effective strategy, with MS clinics being the most time-consuming and most costly. To reach recruitment targets in a timely fashion, a variety of methods were employed. Although consultant mail-outs were the most cost-effective recruitment strategy, use of this
12. Human placenta-derived cells (PDA-001) for the treatment of adults with multiple sclerosis: a randomized, placebo-controlled, multiple-dose study.
Lublin, Fred D; Bowen, James D; Huddlestone, John; Kremenchutzky, Marcelo; Carpenter, Adam; Corboy, John R; Freedman, Mark S; Krupp, Lauren; Paulo, Corri; Hariri, Robert J; Fischkoff, Steven A
2014-11-01
13. Light therapy for multiple sclerosis-associated fatigue: Study protocol for a randomized controlled trial.
Mateen, Farrah J; Manalo, Natalie C; Grundy, Sara J; Houghton, Melissa A; Hotan, Gladia C; Erickson, Hans; Videnovic, Aleksandar
2017-09-01
Fatigue is the most commonly reported symptom among multiple sclerosis (MS) patients, more than a quarter of whom consider fatigue to be their most disabling symptom. However, there are few effective treatment options for fatigue. We aim to investigate whether supplemental exposure to bright white light will reduce MS-associated fatigue. Eligible participants will have clinically confirmed multiple sclerosis based on the revised McDonald criteria (2010) and a score ≥36 on the Fatigue Severity Scale (FSS). Participants will be randomized 1:1 to bright white light (10,000 lux; active condition) or dim red light (treatment period, and a 4-week washout period. Participants will record their sleep duration, exercise, caffeine, and medication intake daily. Participants will record their fatigue using the Visual Analogue Fatigue Scale (VAFS) 4 times every third day, providing snapshots of their fatigue level at different times of day. Participants will self-report their fatigue severity using FSS on 3 separate visits: at baseline (week 0), following completion of the treatment phase (week 6), and at study completion (week 10). The primary outcome will be the change in the average FSS score after light therapy. We will perform an intention-to-treat analysis, comparing the active and control groups to assess the postintervention difference in fatigue levels reported on FSS. Secondary outcome measures include change in global VAFS scores during the light therapy and self-reported quality of life in the Multiple Sclerosis Quality of Life-54. We present a study design and rationale for randomizing a nonpharmacological intervention for MS-associated fatigue, using bright light therapy. The study limitations relate to the logistical issues of a self-administered intervention requiring frequent participant self-report in a relapsing condition. Ultimately, light therapy for the treatment of MS-associated fatigue may provide a low-cost, noninvasive, self-administered treatment
14. Improvements in cognition, quality of life, and physical performance with clinical Pilates in multiple sclerosis: a randomized controlled trial.
Küçük, Fadime; Kara, Bilge; Poyraz, Esra Çoşkuner; İdiman, Egemen
2016-03-01
[Purpose] The aim of this study was to determine the effects of clinical Pilates in multiple sclerosis patients. [Subjects and Methods] Twenty multiple sclerosis patients were enrolled in this study. The participants were divided into two groups as the clinical Pilates and control groups. Cognition (Multiple Sclerosis Functional Composite), balance (Berg Balance Scale), physical performance (timed performance tests, Timed up and go test), tiredness (Modified Fatigue Impact scale), depression (Beck Depression Inventory), and quality of life (Multiple Sclerosis International Quality of Life Questionnaire) were measured before and after treatment in all participants. [Results] There were statistically significant differences in balance, timed performance, tiredness and Multiple Sclerosis Functional Composite tests between before and after treatment in the clinical Pilates group. We also found significant differences in timed performance tests, the Timed up and go test and the Multiple Sclerosis Functional Composite between before and after treatment in the control group. According to the difference analyses, there were significant differences in Multiple Sclerosis Functional Composite and Multiple Sclerosis International Quality of Life Questionnaire scores between the two groups in favor of the clinical Pilates group. There were statistically significant clinical differences in favor of the clinical Pilates group in comparison of measurements between the groups. Clinical Pilates improved cognitive functions and quality of life compared with traditional exercise. [Conclusion] In Multiple Sclerosis treatment, clinical Pilates should be used as a holistic approach by physical therapists.
15. A Limb Action Detector Enabling People with Multiple Disabilities to Control Environmental Stimulation through Limb Action with a Nintendo Wii Remote Controller
Shih, Ching-Hsiang; Chang, Man-Ling; Shih, Ching-Tien
2010-01-01
This study assessed whether two persons with multiple disabilities would be able to control environmental stimulation using limb action with a Nintendo Wii Remote Controller and a newly developed limb action detection program (LADP, i.e., a new software program that turns a Wii Remote Controller into a precise limb action detector). This study was…
16. Multiple memory systems, multiple time points: how science can inform treatment to control the expression of unwanted emotional memories.
Visser, Renée M; Lau-Zhu, Alex; Henson, Richard N; Holmes, Emily A
2018-03-19
Memories that have strong emotions associated with them are particularly resilient to forgetting. This is not necessarily problematic, however some aspects of memory can be. In particular, the involuntary expression of those memories, e.g. intrusive memories after trauma, are core to certain psychological disorders. Since the beginning of this century, research using animal models shows that it is possible to change the underlying memory, for example by interfering with its consolidation or reconsolidation. While the idea of targeting maladaptive memories is promising for the treatment of stress and anxiety disorders, a direct application of the procedures used in non-human animals to humans in clinical settings is not straightforward. In translational research, more attention needs to be paid to specifying what aspect of memory (i) can be modified and (ii) should be modified. This requires a clear conceptualization of what aspect of memory is being targeted, and how different memory expressions may map onto clinical symptoms. Furthermore, memory processes are dynamic, so procedural details concerning timing are crucial when implementing a treatment and when assessing its effectiveness. To target emotional memory in its full complexity, including its malleability, science cannot rely on a single method, species or paradigm. Rather, a constructive dialogue is needed between multiple levels of research, all the way 'from mice to mental health'.This article is part of a discussion meeting issue 'Of mice and mental health: facilitating dialogue between basic and clinical neuroscientists'. © 2018 The Authors.
17. Decentralized Model Predictive Control for Cooperative Multiple Vehicles Subject to Communication Loss
2011-01-01
Full Text Available The decentralized model predictive control (DMPC of multiple cooperative vehicles with the possibility of communication loss/delay is investigated. The neighboring vehicles exchange their predicted trajectories at every sample time to maintain the cooperation objectives. In the event of a communication loss (packet dropout, the most recent available information, which is potentially delayed, is used. Then the communication loss problem changes to a cooperative problem when random large communication delays are present. Such large communication delays can lead to poor cooperation performance and unsafe behaviors such as collisions. A new DMPC approach is developed to improve the cooperation performance and achieve safety in the presence of the large communication delays. The proposed DMPC architecture estimates the tail of neighbor's trajectory which is not available due to the large communication delays for improving the performance. The concept of the tube MPC is also employed to provide the safety of the fleet against collisions, in the presence of large intervehicle communication delays. In this approach, a tube shaped trajectory set is assumed around the trajectory of the neighboring vehicles whose trajectory is delayed/lost. The radius of tube is a function of the communication delay and vehicle's maneuverability (in the absence of model uncertainty. The simulation of formation problem of multiple vehicles is employed to illustrate the effectiveness of the proposed approach.
18. Structural controls on the megathrust segmentation of the Middle America Trench from multiple geophysical observations
Naif, S.; Bassett, D.
2016-12-01
Subduction zone megathrusts display complex seismogenic behaviors that vary at intra- and inter-margin scales. Many different physical properties have been proposed to be primarily responsible for this behavior, such as the composition of subducted sediments, the hydration state of the incoming oceanic plate, and the pore-fluid pressure at the plate interface. Here, we focus on the northern Middle America Trench and show that subducting plate structures control megathrust segmentation. We analyze multiple types of seafloor geophysical observations and compare them to the distinct behavioral and spatial characteristics of the 1992 Nicaragua (Mw7.6), 2012 El Salvador (Mw7.3), 2012 Guatemala (Mw7.4), and 2012 Costa Rica (Mw7.6) events. The residual topography, residual gravity, and magnetic anomaly structure of the incoming oceanic plate and forearc seafloor are correlated. The forearc is composed of multiple unique segments that are bounded by subducting fracture zones. These boundaries correlate with foreshock and aftershock seismicity and also coincide with the hypocenter of all four earthquakes. The relationship between observed structures, earthquake slip inversions, and radiated energy of the four large events will be discussed.
19. Glucose uptake heterogeneity of the leg muscles is similar between patients with multiple sclerosis and healthy controls during walking.
Kindred, John H; Ketelhut, Nathaniel B; Rudroff, Thorsten
2015-02-01
Difficulties in ambulation are one of the main problems reported by patients with multiple sclerosis. A previous study by our research group showed increased recruitment of muscle groups during walking, but the influence of skeletal muscle properties, such as muscle fiber activity, has not been fully elucidated. The purpose of this investigation was to use the novel method of calculating glucose uptake heterogeneity in the leg muscles of patients with multiple sclerosis and compare these results to healthy controls. Eight patients with multiple sclerosis (4 men) and 8 healthy controls (4 men) performed 15 min of treadmill walking at a comfortable self-selected speed following muscle strength tests. Participants were injected with ≈ 8 mCi of [(18)F]-fluorodeoxyglucose during walking after which positron emission tomography/computed tomography imaging was performed. No differences in muscle strength were detected between multiple sclerosis and control groups (P>0.27). Within the multiple sclerosis, group differences in muscle volume existed between the stronger and weaker legs in the vastus lateralis, semitendinosus, and semimembranosus (Pmuscle group or individual muscle of the legs (P>0.16, P≥0.05). Patients with multiple sclerosis and healthy controls showed similar muscle fiber activity during walking. Interpretations of these results, with respect to our previous study, suggest that walking difficulties in patients with multiple sclerosis may be more associated with altered central nervous system motor patterns rather than alterations in skeletal muscle properties. Published by Elsevier Ltd.
20. Multimodal exercise training in multiple sclerosis: A randomized controlled trial in persons with substantial mobility disability.
Sandroff, Brian M; Bollaert, Rachel E; Pilutti, Lara A; Peterson, Melissa L; Baynard, Tracy; Fernhall, Bo; McAuley, Edward; Motl, Robert W
2017-10-01
Mobility disability is a common, debilitating feature of multiple sclerosis (MS). Exercise training has been identified as an approach to improve MS-related mobility disability. However, exercise randomized controlled trials (RCTs) on mobility in MS have generally not selectively targeted those with the onset of irreversible mobility disability. The current multi-site RCT compared the efficacy of 6-months of supervised, multimodal exercise training with an active control condition for improving mobility, gait, physical fitness, and cognitive outcomes in persons with substantial MS-related mobility disability. 83 participants with substantial MS-related mobility disability underwent initial mobility, gait, fitness, and cognitive processing speed assessments and were randomly assigned to 6-months of supervised multimodal (progressive aerobic, resistance, and balance) exercise training (intervention condition) or stretching-and-toning activities (control condition). Participants completed the same outcome assessments halfway through and immediately following the 6-month study period. There were statistically significant improvements in six-minute walk performance (F(2158)=3.12, p=0.05, η p 2 =0.04), peak power output (F(2150)=8.16, pmobility disability. This is critical for informing the development of multi-site exercise rehabilitation programs in larger samples of persons with MS-related mobility disability. Copyright © 2017 Elsevier Inc. All rights reserved.
1. Tracking Control Based on Recurrent Neural Networks for Nonlinear Systems with Multiple Inputs and Unknown Deadzone
J. Humberto Pérez-Cruz
2012-01-01
Full Text Available This paper deals with the problem of trajectory tracking for a broad class of uncertain nonlinear systems with multiple inputs each one subject to an unknown symmetric deadzone. On the basis of a model of the deadzone as a combination of a linear term and a disturbance-like term, a continuous-time recurrent neural network is directly employed in order to identify the uncertain dynamics. By using a Lyapunov analysis, the exponential convergence of the identification error to a bounded zone is demonstrated. Subsequently, by a proper control law, the state of the neural network is compelled to follow a bounded reference trajectory. This control law is designed in such a way that the singularity problem is conveniently avoided and the exponential convergence to a bounded zone of the difference between the state of the neural identifier and the reference trajectory can be proven. Thus, the exponential convergence of the tracking error to a bounded zone and the boundedness of all closed-loop signals can be guaranteed. One of the main advantages of the proposed strategy is that the controller can work satisfactorily without any specific knowledge of an upper bound for the unmodeled dynamics and/or the disturbance term.
2. Discrete event command and control for networked teams with multiple missions
Lewis, Frank L.; Hudas, Greg R.; Pang, Chee Khiang; Middleton, Matthew B.; McMurrough, Christopher
2009-05-01
During mission execution in military applications, the TRADOC Pamphlet 525-66 Battle Command and Battle Space Awareness capabilities prescribe expectations that networked teams will perform in a reliable manner under changing mission requirements, varying resource availability and reliability, and resource faults. In this paper, a Command and Control (C2) structure is presented that allows for computer-aided execution of the networked team decision-making process, control of force resources, shared resource dispatching, and adaptability to change based on battlefield conditions. A mathematically justified networked computing environment is provided called the Discrete Event Control (DEC) Framework. DEC has the ability to provide the logical connectivity among all team participants including mission planners, field commanders, war-fighters, and robotic platforms. The proposed data management tools are developed and demonstrated on a simulation study and an implementation on a distributed wireless sensor network. The results show that the tasks of multiple missions are correctly sequenced in real-time, and that shared resources are suitably assigned to competing tasks under dynamically changing conditions without conflicts and bottlenecks.
3. Hydrotherapy for the Treatment of Pain in People with Multiple Sclerosis: A Randomized Controlled Trial
2012-01-01
Full Text Available Background. Multiple sclerosis (MS is a chronic demyelinating neurological disease. Several studies have reported that complementary and alternative therapies can have positive effects against pain in these patients. Objective. The objective was to investigate the effectiveness of an Ai-Chi aquatic exercise program against pain and other symptoms in MS patients. Methods. In this randomized controlled trial, 73 MS patients were randomly assigned to an experimental or control group for a 20-week treatment program. The experimental group underwent 40 sessions of Ai-Chi exercise in swimming pool and the control group 40 sessions of abdominal breathing and contraction-relaxation exercises in therapy room. Outcome variables were pain, disability, spasm, depression, fatigue, and autonomy, which were assessed before the intervention and immediately and at 4 and 10 weeks after the last treatment session. Results. The experimental group showed a significant (P<0.028 and clinically relevant decrease in pain intensity versus baseline, with an immediate posttreatment reduction in median visual analogue scale scores of 50% that was maintained for up to 10 weeks. Significant improvements were also observed in spasm, fatigue, disability, and autonomy. Conclusion. According to these findings, an Ai-Chi aquatic exercise program improves pain, spasms, disability, fatigue, depression, and autonomy in MS patients.
4. Hydrotherapy for the treatment of pain in people with multiple sclerosis: a randomized controlled trial.
Castro-Sánchez, Adelaida María; Matarán-Peñarrocha, Guillermo A; Lara-Palomo, Inmaculada; Saavedra-Hernández, Manuel; Arroyo-Morales, Manuel; Moreno-Lorenzo, Carmen
2012-01-01
Background. Multiple sclerosis (MS) is a chronic demyelinating neurological disease. Several studies have reported that complementary and alternative therapies can have positive effects against pain in these patients. Objective. The objective was to investigate the effectiveness of an Ai-Chi aquatic exercise program against pain and other symptoms in MS patients. Methods. In this randomized controlled trial, 73 MS patients were randomly assigned to an experimental or control group for a 20-week treatment program. The experimental group underwent 40 sessions of Ai-Chi exercise in swimming pool and the control group 40 sessions of abdominal breathing and contraction-relaxation exercises in therapy room. Outcome variables were pain, disability, spasm, depression, fatigue, and autonomy, which were assessed before the intervention and immediately and at 4 and 10 weeks after the last treatment session. Results. The experimental group showed a significant (P < 0.028) and clinically relevant decrease in pain intensity versus baseline, with an immediate posttreatment reduction in median visual analogue scale scores of 50% that was maintained for up to 10 weeks. Significant improvements were also observed in spasm, fatigue, disability, and autonomy. Conclusion. According to these findings, an Ai-Chi aquatic exercise program improves pain, spasms, disability, fatigue, depression, and autonomy in MS patients.
5. Fuzzy comprehensive evaluation of multiple environmental factors for swine building assessment and control.
Xie, Qiuju; Ni, Ji-Qin; Su, Zhongbin
2017-10-15
In confined swine buildings, temperature, humidity, and air quality are all important for animal health and productivity. However, the current swine building environmental control is only based on temperature; and evaluation and control methods based on multiple environmental factors are needed. In this paper, fuzzy comprehensive evaluation (FCE) theory was adopted for multi-factor assessment of environmental quality in two commercial swine buildings using real measurement data. An assessment index system and membership functions were established; and predetermined weights were given using analytic hierarchy process (AHP) combined with knowledge of experts. The results show that multi-factors such as temperature, humidity, and concentrations of ammonia (NH 3 ), carbon dioxide (CO 2 ), and hydrogen sulfide (H 2 S) can be successfully integrated in FCE for swine building environment assessment. The FCE method has a high correlation coefficient of 0.737 compared with the method of single-factor evaluation (SFE). The FCE method can significantly increase the sensitivity and perform an effective and integrative assessment. It can be used as part of environmental controlling and warning systems for swine building environment management to improve swine production and welfare. Copyright © 2017 Elsevier B.V. All rights reserved.
6. Vibration control of buildings by using partial floor loads as multiple tuned mass
Tharwat A. Sakr
2017-08-01
Full Text Available Tuned mass dampers (TMDs are considered as the most common control devices used for protecting high-rise buildings from vibrations. Because of their simplicity and efficiency, they have found wide practical applications in high-rise buildings around the world. This paper proposes an innovative technique for using partial floor loads as multiple TMDs at limited number of floors. This technique eliminates complications resulting from the addition of huge masses required for response control and maintains the mass of the original structure without any added loads. The effects of using partial loads of limited floors starting from the top as TMDs on the vibration response of buildings to wind and earthquakes are investigated. The effects of applying the proposed technique to buildings with different heights and characteristics are also investigated. A parametric study is carried out to illustrate how the behavior of a building is affected by the number of stories and the portion of the floor utilized as TMDs. Results indicate the effectiveness of the proposed control technique in enhancing the drift, acceleration, and force response of buildings to wind and earthquakes. The response of buildings to wind and earthquakes was observed to be more enhanced by increasing the story-mass ratios and the number of floor utilized as TMDs.
7. The Role of Clinical and Instrumented Outcome Measures in Balance Control of Individuals with Multiple Sclerosis
Neeta Kanekar
2013-01-01
Full Text Available Purpose. The aim of the study was to investigate differences in balance control between individuals with multiple sclerosis (MS and healthy control subjects using clinical scales and instrumented measures of balance and determine relationships between balance measures, fatigue, and disability levels in individuals with MS with and without a history of falls. Method. Twelve individuals with MS and twelve healthy controls were evaluated using the Berg Balance and Activities-specific Balance Confidence Scales, Modified Clinical Test of Sensory Interaction on Balance, and Limits of Stability Tests as well as Fatigue Severity Scale and Barthel Index. Results. Mildly affected individuals with MS had significant balance performance deficits and poor balance confidence levels (P<0.05. MS group had higher sway velocities and diminished stability limits (P<0.05, significant sensory impairments, high fatigue and disability levels (P<0.05. Sway velocity was a significant predictor of balance performance and the ability to move towards stability limits for the MS group. For the MS-fallers group, those with lower disability levels had faster movement velocities and better balance performance. Conclusion. Implementation of both clinical and instrumented tests of balance is important for the planning and evaluation of treatment outcomes in balance rehabilitation of people with MS.
8. Fine-mapping and cross-validation of QTLs linked to fatty acid composition in multiple independent interspecific crosses of oil palm.
Ting, Ngoot-Chin; Yaakub, Zulkifli; Kamaruddin, Katialisa; Mayes, Sean; Massawe, Festo; Sambanthamurthi, Ravigadevi; Jansen, Johannes; Low, Leslie Eng Ti; Ithnin, Maizura; Kushairi, Ahmad; Arulandoo, Xaviar; Rosli, Rozana; Chan, Kuang-Lim; Amiruddin, Nadzirah; Sritharan, Kandha; Lim, Chin Ching; Nookiah, Rajanaidu; Amiruddin, Mohd Din; Singh, Rajinder
2016-04-14
The commercial oil palm (Elaeis guineensis Jacq.) produces a mesocarp oil (commonly called 'palm oil') with approximately equal proportions of saturated and unsaturated fatty acids (FAs). An increase in unsaturated FAs content or iodine value (IV) as a measure of the degree of unsaturation would help to open up new markets for the oil. One way to manipulate the fatty acid composition (FAC) in palm oil is through introgression of favourable alleles from the American oil palm, E. oleifera, which has a more unsaturated oil. In this study, a segregating E. oleifera x E. guineensis (OxG) hybrid population for FAC is used to identify quantitative trait loci (QTLs) linked to IV and various FAs. QTL analysis revealed 10 major and two putative QTLs for IV and six FAs, C14:0, C16:0, C16:1, C18:0, C18:1 and C18:2 distributed across six linkage groups (LGs), OT1, T2, T3, OT4, OT6 and T9. The major QTLs for IV and C16:0 on LGOT1 explained 60.0 - 69.0 % of the phenotypic trait variation and were validated in two independent BC2 populations. The genomic interval contains several key structural genes in the FA and oil biosynthesis pathways such as PATE/FATB, HIBCH, BASS2, LACS4 and DGAT1 and also a relevant transcription factor (TF), WRI1. The literature suggests that some of these genes can exhibit pleiotropic effects in the regulatory networks of these traits. Using the whole genome sequence data, markers tightly linked to the candidate genes were also developed. Clustering trait values according to the allelic forms of these candidate markers revealed significant differences in the IV and FAs of the palms in the mapping and validation crosses. The candidate gene approach described and exploited here is useful to identify the potential causal genes linked to FAC and can be adopted for marker-assisted selection (MAS) in oil palm.
9. Suicidality and divalproex sodium: analysis of controlled studies in multiple indications
Kovacs Xenia
2011-01-01
Full Text Available Abstract Background Recent analyses of antiepileptic drugs have indicated an increase in the risk of suicidality. The objective of this report was to provide clinical information and an independent meta-analysis of divalproex sodium and suicidality events by analyzing data from 13 placebo-controlled studies and 1 low-dose controlled study. Methods Adverse events considered to be possibly suicide related were identified using the Columbia Classification Algorithm of Suicide Assessment (C-CASA methodology. Indications included epilepsy, bipolar disorder, migraine prophylaxis, impulsive aggression, and dementia. Narratives were produced for every event, and suicidality event ratings were performed by a third party blinded to treatment assignment. Statistical analyses were conducted using methodology similar to that reported by the US Food and Drug Administration (FDA. Results Suicidality events were identified in 5 of the 13 placebo-controlled studies. Of the 1,327 (0.83% subjects taking divalproex sodium, 11 had suicidality events: 2 suicide attempts and 9 suicidal ideation. Of 992 (0.91% subjects taking placebo, 9 had suicidality events: 1 preparatory act toward suicide, 2 suicide attempts, and 6 suicidal ideation. Across placebo-controlled studies, the overall estimated odds ratio (OR of suicidal behavior or ideation was 0.72 (95% CI 0.29 to 1.84. The OR for suicidal behavior was 0.37 (95% CI 0.04 to 2.58, and the OR for suicidal ideation was 0.90 (95% CI 0.31 to 2.79. Conclusions In this meta-analysis, divalproex sodium does not appear to increase the risk of suicide-related adverse events relative to placebo in the populations studied. Clinicians should nonetheless remain vigilant in assessing suicidality, not only in patients treated for mental disorders with inherently high suicide risk, but also in patients taking antiepileptic medications.
10. Identity crisis: user perspectives on multiplicity and control in federated identitymanagement
Howard, Steve; Satchell, C; Shanks, G
2009-01-01
Federated identity management systems synthesise complex and fragmented user information into a single entity. Literature from the provider’s perspective notes this integration extends many benefits to the end user and the privileges provided by digital identity authentication schemes have been...... well documented from this perspective. Less explored are the perceptions of federation from the user’s perspective. This study reports an empirical user study that examines the relationship between identity and technology using contextual interviews, focus groups and cultural probes. It emerges...... that while current federated systems satisfy user needs by allowing the construction of multiple digital data sets that are moored to a central identifier, they fail to provide the user with control over the capability to act in the ‘hatch’, ‘match’ and ‘dispatch’ phases of the digital identity lifecycle...
11. Use of multiple water surface flow constructed wetlands for non-point source water pollution control.
Li, Dan; Zheng, Binghui; Liu, Yan; Chu, Zhaosheng; He, Yan; Huang, Minsheng
2018-05-02
Multiple free water surface flow constructed wetlands (multi-FWS CWs) are a variety of conventional water treatment plants for the interception of pollutants. This review encapsulated the characteristics and applications in the field of ecological non-point source water pollution control technology. The roles of in-series design and operation parameters (hydraulic residence time, hydraulic load rate, water depth and aspect ratio, composition of influent, and plant species) for performance intensification were also analyzed, which were crucial to achieve sustainable and effective contaminants removal, especially the retention of nutrient. The mechanism study of design and operation parameters for the removal of nitrogen and phosphorus was also highlighted. Conducive perspectives for further research on optimizing its design/operation parameters and advanced technologies of ecological restoration were illustrated to possibly interpret the functions of multi-FWS CWs.
12. Using Natural Language to Enable Mission Managers to Control Multiple Heterogeneous UAVs
Trujillo, Anna C.; Puig-Navarro, Javier; Mehdi, S. Bilal; Mcquarry, A. Kyle
2016-01-01
The availability of highly capable, yet relatively cheap, unmanned aerial vehicles (UAVs) is opening up new areas of use for hobbyists and for commercial activities. This research is developing methods beyond classical control-stick pilot inputs, to allow operators to manage complex missions without in-depth vehicle expertise. These missions may entail several heterogeneous UAVs flying coordinated patterns or flying multiple trajectories deconflicted in time or space to predefined locations. This paper describes the functionality and preliminary usability measures of an interface that allows an operator to define a mission using speech inputs. With a defined and simple vocabulary, operators can input the vast majority of mission parameters using simple, intuitive voice commands. Although the operator interface is simple, it is based upon autonomous algorithms that allow the mission to proceed with minimal input from the operator. This paper also describes these underlying algorithms that allow an operator to manage several UAVs.
13. Quantized flocking control for second-order multiple agents with obstacle avoidance
Chunguang Li
2016-01-01
Full Text Available A quantized flocking control for a group of second-order multiple agents with obstacle avoidance is proposed to address the problem of the exchange of information needed for quantification. With a reasonable assumption, a logarithmic or uniform quantizer is used for the exchange of relative position and velocity information between adjacent agents and the virtual leader, moving at a steady speed along a straight line, and a distributed flocking algorithm with obstacle avoidance capability is designed based on the quantitative information. The Lyapunov stability criterion of nonsmooth systems and the invariance principle are used to prove the stability of these systems. The simulations and experiments are presented to demonstrate the feasibility and effectiveness of the proposed approach.
14. Optimal Exponential Synchronization of Chaotic Systems with Multiple Time Delays via Fuzzy Control
Feng-Hsiag Hsiao
2013-01-01
Full Text Available This study presents an effective approach to realize the optimal exponential synchronization of multiple time-delay chaotic (MTDC systems. First, a neural network (NN model is employed to approximate the MTDC system. Then, a linear differential inclusion (LDI state-space representation is established for the dynamics of the NN model. Based on this LDI state-space representation, this study proposes a delay-dependent exponential stability criterion of the error system derived in terms of Lyapunov’s direct method to ensure that the trajectories of the slave system can approach those of the master system. Subsequently, the stability condition of this criterion is reformulated into a linear matrix inequality (LMI. Based on the LMI, a fuzzy controller is synthesized not only to realize the exponential synchronization but also to achieve the optimal performance by minimizing the disturbance attenuation level. Finally, a numerical example with simulations is provided to illustrate the concepts discussed throughout this work.
15. [Operative treatment strategies for multiple trauma patients : early total care versus damage control].
Klüter, T; Lippross, S; Oestern, S; Weuster, M; Seekamp, A
2013-09-01
The treatment of multiple trauma patients is a great challenge for an interdisciplinary team. After preclinical care and subsequent treatment in the emergency room the order of the interventions is prioritized depending of the individual risk stratification. For planning the surgery management it is essential to distinguish between absolutely essential operations to prevent life-threatening situations for the patient and interventions with shiftable indications, depending on the general condition of the patient. All interventions need to be done without causing significant secondary damage to prohibit hyperinflammation and systemic inflammatory response syndrome. The challenge consists in determination of the appropriate treatment at the right point in time. In general the early primary intervention, early total care, is differentiated from the damage control concept.
16. Multiple crises and independences: Spain and its Monarchy Crisis e independencias: España y su monarquía
José María PORTILLO VALDÉS
2009-05-01
Full Text Available This article focuses on how the concept and practice of representation evolved during the crisis of the Spanish monarchy from 1808 onwards. It first proposes a conception of the crisis of the monarchy as a multiple process in which it evolved from a dynastic crisis to a constitutional one. Simultaneously to this evolution America appeared to be a decisive element for the solution of the crisis since it was declared an «essential» part of the Spanish monarchy by the Junta Central in 1809, ending the distinction between the metropolitan and colonial parts. This declaration was well accepted by a good part of the criollo elite whereas it was culturally impossible for the Spanish liberals to manage it in constitutional terms. This article analyses the consequences of this disruption between declarative and practical aspects of the first Spanish constitutional experience.Este artículo se centra en el estudio de la concepción y la práctica de la representación en el contexto de la crisis de la monarquía española desde 1808. Propone una interpretación compleja de la crisis señalando una evolución desde su dimensión dinástica hasta la constitucional. En la evolución de esa crisis, América resultó ser una pieza decisiva para su solución, desde que la Junta Central declarara en 1809 que conformaba una parte «esencial» de la monarquía, poniendo fin a la idea de una distinción entre parte metropolitana y colonial. Esta declaración fue asumida por buena parte de las elites criollas a la vez que los liberales españoles mostraron serias dificultades culturales para darle consecuencia constitucional. Este artículo analiza las consecuencias de esta bifurcación entre declaraciones y prácticas constitucionales.
17. Impact of a Pelvic Floor Training Program Among Women with Multiple Sclerosis: A Controlled Clinical Trial.
Ferreira, Ana Paula Silva; Pegorare, Ana Beatriz Gomes de Souza; Salgado, Pedro Rippel; Casafus, Filemón Silva; Christofoletti, Gustavo
2016-01-01
The objective of this study was to investigate the effects of two programs for strengthening the pelvic floor on the urinary incontinence of patients with multiple sclerosis (MS). This is a prospective study of the clinical trial type, monitored for 6 mos, in which 24 women in the moderate stage of MS participated in a program of exercises for strengthening the pelvic floor-associated (experimental group) or not (control group) with electrotherapy. The variables analyzed were as follows: quality-of-life, overactivity of the bladder, perineal contraction, and level of anxiety and depression. The statistical procedures involved multivariate analyses of repeated measurements, with a significance of 5%. Initial homogeneity being observed in the anthropometric and clinical variables, both protocols resulted in improvements in quality-of-life (P = 0.001), overactive bladder (P = 0.001), perineal contraction (P = 0.004), and level of anxiety (P = 0.001) and depression (P = 0.001), in relation to the initial comparison. The association of electrotherapy with strengthening exercises increased the improvement of the patients regarding overactive bladder (P = 0.039) and perineal contraction (P = 0.001), in comparison with the control group. The results reinforce the benefit of exercises for strengthening the musculature of the pelvic floor in women with overactive bladder in MS and demonstrate a potential of the action when associated with electrotherapy. Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME OBJECTIVES:: Upon completion of this article, the reader should be able to: (1) Identify common dysfunctions of the lower urinary tract in women with multiple sclerosis; (2) Discuss the relationship between quality-of-life, level of anxiety and depression, degree of perineal contraction, and overactive bladder; and (3) Recognize the benefits promoted by physical therapy for strengthening the pelvic floor in patients with
18. Rapid top-down control over template-guided attention shifts to multiple objects.
Grubert, Anna; Fahrenfort, Johannes; Olivers, Christian N L; Eimer, Martin
2017-02-01
Previous research has shown that when observers search for targets defined by a particular colour, attention can be directed rapidly and independently to two target objects that appear in close temporal proximity. We investigated how such rapid attention shifts are modulated by task instructions to selectively attend versus ignore one of these objects. Two search displays that both contained a colour-defined target and a distractor in a different colour were presented in rapid succession, with a stimulus onset asynchrony (SOA) of 100ms. In different blocks, participants were instructed to attend and respond to target-colour objects in the first display and to ignore these objects in the second display, or vice versa. N2pc components were measured to track the allocation of spatial attention to target-colour objects in these two displays. When participants responded to the second display, irrelevant target-colour objects in the first display still triggered N2pc components, demonstrating task-set contingent attentional capture while a feature-specific target template is active. Critically, when participants responded to the first display instead, no N2pc was elicited by target-colour items in the second display, indicating that they no longer rapidly captured attention. However, these items still elicited a longer-latency contralateral negativity (SPCN component), suggesting that attention was oriented towards template-matching objects in working memory. This dissociation between N2pc and SPCN components shows that rapid attentional capture and subsequent attentional selection processes within working memory can be independent. We suggest that early attentional orienting mechanisms can be inhibited when task-set matching objects are no longer task-relevant, and that this type of inhibitory control is a rapid but transient process. Copyright © 2016 Elsevier Inc. All rights reserved.
19. Deep breathing exercises with positive expiratory pressure in patients with multiple sclerosis - a randomized controlled trial.
Westerdahl, Elisabeth; Wittrin, Anna; Kånåhols, Margareta; Gunnarsson, Martin; Nilsagård, Ylva
2016-11-01
Breathing exercises with positive expiratory pressure are often recommended to patients with advanced neurological deficits, but the potential benefit in multiple sclerosis (MS) patients with mild and moderate symptoms has not yet been investigated in randomized controlled trials. To study the effects of 2 months of home-based breathing exercises for patients with mild to moderate MS on respiratory muscle strength, lung function, and subjective breathing and health status outcomes. Forty-eight patients with MS according to the revised McDonald criteria were enrolled in a randomized controlled trial. Patients performing breathing exercises (n = 23) were compared with a control group (n = 25) performing no breathing exercises. The breathing exercises were performed with a positive expiratory pressure device (10-15 cmH 2 O) and consisted of 30 slow deep breaths performed twice a day for 2 months. Respiratory muscle strength (maximal inspiratory and expiratory pressure at the mouth), spirometry, oxygenation, thoracic excursion, subjective perceptions of breathing and self-reported health status were evaluated before and after the intervention period. Following the intervention, there was a significant difference between the breathing group and the control group regarding the relative change in lung function, favoring the breathing group (vital capacity: P < 0.043; forced vital capacity: P < 0.025). There were no other significant differences between the groups. Breathing exercises may be beneficial in patients with mild to moderate stages of MS. However, the clinical significance needs to be clarified, and it remains to be seen whether a sustainable effect in delaying the development of respiratory dysfunction in MS can be obtained. © 2015 The Authors. The Clinical Respiratory Journal published by John Wiley & Sons Ltd.
20. Not a single but multiple populations of GABAergic neurons control sleep.
Luppi, Pierre-Hervé; Peyron, Christelle; Fort, Patrice
2017-04-01
The role of gamma-amino butyric acid (GABA) in sleep induction and maintenance is well accepted since most insomnia treatments target GABAa receptors. However, the population(s) of GABAergic neurons involved in the beneficial effect of GABA on sleep remains to be identified. This is not an easy task since GABAergic neurons are widely distributed in all brain structures. A recently growing number of populations of GABAergic neurons have been involved in sleep control. We first review here possible candidates for inducing non-rapid eye movement (NREM) sleep including the GABAergic neurons of the ventrolateral preoptic area, the parafacial zone in the brainstem, the nucleus accumbens and the cortex. We also discuss the role of several populations of GABAergic neurons in rapid eye movement (REM) sleep control. Indeed, it is well accepted that muscle atonia occurring during REM sleep is due to a GABA/glycinergic hyperpolarization of motoneurons. Recent evidence strongly suggests that these neurons are located in the ventral medullary reticular formation. It has also recently been shown that neurons containing the neuropeptide melanin concentrating hormone and GABA located in the lateral hypothalamic area control REM sleep expression. Finally, a population of REM-off GABAergic neurons located in the ventrolateral periaqueductal gray has been shown to gate REM sleep by inhibiting glutamatergic neurons located in the sublaterodorsal tegmental nucleus. In summary, recent data clearly indicate that multiple populations of GABAergic neurons located throughout the brain from the cortex to the medulla oblongata control NREM and REM sleep. Copyright © 2016 Elsevier Ltd. All rights reserved.
1. Falls prevention and balance rehabilitation in multiple sclerosis: a bi-centre randomised controlled trial.
Cattaneo, Davide; Rasova, Kamila; Gervasoni, Elisa; Dobrovodská, Gabriela; Montesano, Angelo; Jonsdottir, Johanna
2018-03-01
People with Multiple Sclerosis (PwMS) have a high incidence of accidental falls that have a potentially detrimental effect on their daily life participation. The effect of balance specific rehabilitation on clinical balance measures and frequency of falls in PwMS was studied. A bi-centre randomised rater-blinded controlled trial. Participants in both groups received 20 treatment sessions. Participants in the intervention group received treatment aimed at improving balance and mobility. Participants in the control group received treatments to reduce limitations at activity and body function level. Primary measures were frequency of fallers (>1 fall in two months) and responders (>3 points improvement) at the Berg Balance Scale (BBS). Data was analysed according to an intention to treat approach. One hundred and nineteen participants were randomised. Following treatment frequency of fallers was 22% in the intervention group and 23% in the control group, odds ratio (OR) and (confidence limits): 1.05 (0.41 to 2.77). Responders on the BBS were 28% in the intervention group and 33% in the control group, OR = 0.75 (0.30 to 1.91). At follow up ORs for fallers and responders at BBS were 0.98 (0.48 to 2.01) and 0.79 (0.26 to 2.42), respectively. Twenty sessions 2-3 times/week of balance specific rehabilitation did not reduce fall frequency nor improve balance suggesting the need for more frequent and challenging interventions. Implications for Rehabilitation Programs for balance rehabilitation can improve balance but their effects in fall prevention are unclear. Twenty treatments sessions 2/3 times per week did not reduced frequency of falls in MS. The comparison with similar studies suggests that higher intensity of practice of highly challenging balance activities appears to be critical to maximizing effectiveness.
2. Cognitive function in multiple sclerosis improves with telerehabilitation: Results from a randomized controlled trial.
Leigh E Charvet
Full Text Available Cognitive impairment affects more than half of all individuals living with multiple sclerosis (MS. We hypothesized that training at home with an adaptive online cognitive training program would have greater cognitive benefit than ordinary computer games in cognitively-impaired adults with MS. This was a double-blind, randomized, active-placebo-controlled trial. Participants with MS were recruited through Stony Brook Medicine and randomly assigned to either the adaptive cognitive remediation (ACR program or active control of ordinary computer games for 60 hours over 12 weeks. Training was remotely-supervised and delivered through a study-provided laptop computer. A computer generated, blocked stratification table prepared by statistician provided the randomization schedule and condition was assigned by a study technician. The primary outcome, administered by study psychometrician, was measured by change in a neuropsychological composite measure from baseline to study end. An intent-to-treat analysis was employed and missing primary outcome values were imputed via Markov Chain Monte Carlo method. Participants in the ACR (n = 74 vs. active control (n = 61 training program had significantly greater improvement in the primary outcome of cognitive functioning (mean change in composite z score±SD: 0·25±0·45 vs. 0·09±0·37, p = 0·03, estimated difference = 0·16 with 95% CI: 0·02-0·30, despite greater training time in the active control condition (mean±SD:56·9 ± 34·6 vs. 37·7 ±23 ·8 hours played, p = 0·006. This study provides Class I evidence that adaptive, computer-based cognitive remediation accessed from home can improve cognitive functioning in MS. This telerehabilitation approach allowed for rapid recruitment and high compliance, and can be readily applied to other neurological conditions associated with cognitive dysfunction.Clinicaltrials.gov NCT02141386.
3. Independent preferences
Vind, Karl
1991-01-01
A simple mathematical result characterizing a subset of a product set is proved and used to obtain additive representations of preferences. The additivity consequences of independence assumptions are obtained for preferences which are not total or transitive. This means that most of the economic ...... theory based on additive preferences - expected utility, discounted utility - has been generalized to preferences which are not total or transitive. Other economic applications of the theorem are given...
4. Changes of deep gray matter magnetic susceptibility over 2years in multiple sclerosis and healthy control brain
Jesper Hagemeier
Full Text Available In multiple sclerosis, pathological changes of both tissue iron and myelin occur, yet these factors have not been characterized in a longitudinal fashion using the novel iron- and myelin-sensitive quantitative susceptibility mapping (QSM MRI technique. We investigated disease-relevant tissue changes associated with myelin loss and iron accumulation in multiple sclerosis deep gray matter (DGM over two years. One-hundred twenty (120 multiple sclerosis patients and 40 age- and sex-matched healthy controls were included in this prospective study. Written informed consent and local IRB approval were obtained from all participants. Clinical testing and QSM were performed both at baseline and at follow-up. Brain magnetic susceptibility was measured in major DGM structures. Temporal (baseline vs. follow-up and cross-sectional (multiple sclerosis vs. controls differences were studied using mixed factorial ANOVA analysis and appropriate t-tests. At either time-point, multiple sclerosis patients had significantly higher susceptibility in the caudate and globus pallidus and lower susceptibility in the thalamus. Over two years, susceptibility increased significantly in the caudate of both controls and multiple sclerosis patients. Inverse thalamic findings among MS patients suggest a multi-phase pathology explained by simultaneous myelin loss and/or iron accumulation followed by iron depletion and/or calcium deposition at later stages. Keywords: Quantitative susceptibility mapping, QSM, Iron, Multiple sclerosis, Longitudinal study
5. Hippotherapy for patients with multiple sclerosis: A multicenter randomized controlled trial (MS-HIPPO).
Vermöhlen, Vanessa; Schiller, Petra; Schickendantz, Sabine; Drache, Marion; Hussack, Sabine; Gerber-Grote, Andreas; Pöhlau, Dieter
2017-08-01
Evidence-based complementary treatment options for multiple sclerosis (MS) are limited. To investigate the effect of hippotherapy plus standard care versus standard care alone in MS patients. A total of 70 adults with MS were recruited in five German centers and randomly allocated to the intervention group (12 weeks of hippotherapy) or the control group. Primary outcome was the change in the Berg Balance Scale (BBS) after 12 weeks, and further outcome measures included fatigue, pain, quality of life, and spasticity. Covariance analysis of the primary endpoint resulted in a mean difference in BBS change of 2.33 (95% confidence interval (CI): 0.03-4.63, p = 0.047) between intervention ( n = 32) and control ( n = 38) groups. Benefit on BBS was largest for the subgroup with an Expanded Disability Status Scale (EDSS) ⩾ 5 (5.1, p = 0.001). Fatigue (-6.8, p = 0.02) and spasticity (-0.9, p = 0.03) improved in the intervention group. The mean difference in change between groups was 12.0 ( p Hippotherapy plus standard care, while below the threshold of a minimal clinically important difference, significantly improved balance and also fatigue, spasticity, and quality of life in MS patients.
6. Multiple photoreceptor systems control the swim pacemaker activity in box jellyfish
Garm, Anders Lydik; Mori, S.
2009-01-01
Like all other cnidarian medusae, box jellyfish propel themselves through the water by contracting their bell-shaped body in discrete swim pulses. These pulses are controlled by a swim pacemaker system situated in their sensory structures, the rhopalia. Each medusa has four rhopalia each with a s......Like all other cnidarian medusae, box jellyfish propel themselves through the water by contracting their bell-shaped body in discrete swim pulses. These pulses are controlled by a swim pacemaker system situated in their sensory structures, the rhopalia. Each medusa has four rhopalia each...... with a similar set of six eyes of four morphologically different types. We have examined how each of the four eye types influences the swim pacemaker. Multiple photoreceptor systems, three of the four eye types, plus the rhopalial neuropil, affect the swim pacemaker. The lower lens eye inhibits the pacemaker...... when stimulated and provokes a strong increase in the pacemaker frequency upon light-off. The upper lens eye, the pit eyes and the rhopalial neuropil all have close to the opposite effect. When these responses are compared with all-eye stimulations it is seen that some advanced integration must take...
7. Multiple chromatographic fingerprinting and its application to the quality control of herbal medicines
Fan Xiaohui [Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310027 (China); Cheng Yiyu [Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310027 (China)]. E-mail: chengyy@zju.edu.cn; Ye Zhengliang [Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310027 (China); Lin Ruichao [National Institute for the Control of Pharmaceutical and Biological Products, Beijing 100050 (China); Qian Zhongzhi [Committee of Chinese Pharmacopoeia, Beijing 100061 (China)
2006-01-12
Recently, chromatographic fingerprinting has become one of the most powerful approaches to quality control of herbal medicines. However, the performance of reported chromatographic fingerprinting constructed by single chromatogram sometimes turns out to be inadequate for complex herbal medicines, such as multi-herb botanical drug products. In this study, multiple chromatographic fingerprinting, which consists of more than one chromatographic fingerprint and represents the whole characteristics of chemical constitutions of the complex medicine, is proposed as a potential strategy in this complicated case. As a typical example, a binary chromatographic fingerprinting of 'Danshen Dropping Pill' (DSDP), the best-sold traditional Chinese medicine in China, was developed. First, two HPLC fingerprints that, respectively, represent chemical characteristics of depsides and saponins of DSDP were developed, which were used to construct binary chromatographic fingerprints of DSDP. Moreover, the authentication and validation of the binary fingerprints were performed. Then, a data-level information fusion method was employed to capture the chemical information encoded in two chromatographic fingerprints. Based on the fusion results, the lot-to-lot consistency and frauds can be determined either using similarity measure or by chemometrics approach. The application of binary chromatographic fingerprinting to consistency assessment and frauds detection of DSDP clearly demonstrated that the proposed method was a powerful approach to quality control of complex herbal medicines.
8. A case-control study of risk factors for multiple sclerosis in Iran.
Alonso, Alvaro; Cook, Stuart D; Maghzi, Amir-Hadi; Divani, Afshin A
2011-05-01
Numerous studies have assessed risk factors for multiple sclerosis (MS), although none have been conducted previously in Iran. The objective of this study was to study lifestyle and environmental risk factors of MS in the Iranian population. A case-control study, including 394 MS cases and 394 matched controls, was conducted in MS clinics in different Iranian cities. Information on lifestyles, environmental exposures, and past medical history was obtained from medical charts and phone interviews. In multivariable analysis, sunlight exposure was associated with a lower risk of MS: the odds ratio (OR) and 95% confidence interval (CI) of MS associated with a 1-h increment in daily sunlight was 0.62 (0.53-0.73). Smoking was associated with MS risk in women (OR: 6.48, 95% CI: 1.46-28.78), but not in men (OR: 0.72, 95% CI: 0.31-1.68) (p=0.002 for interaction). Finally, past history of common surgical procedures, infectious disorders, or exposure to pets and farm animals was not associated with MS risk. Different modifiable lifestyles, including sunlight exposure and smoking, were associated with lower MS risk in Iran. Interventions aimed at promoting smoking cessation and, more importantly, at increasing exposure to sunlight might contribute to the prevention of MS.
9. Multiple chromatographic fingerprinting and its application to the quality control of herbal medicines
Fan Xiaohui; Cheng Yiyu; Ye Zhengliang; Lin Ruichao; Qian Zhongzhi
2006-01-01
Recently, chromatographic fingerprinting has become one of the most powerful approaches to quality control of herbal medicines. However, the performance of reported chromatographic fingerprinting constructed by single chromatogram sometimes turns out to be inadequate for complex herbal medicines, such as multi-herb botanical drug products. In this study, multiple chromatographic fingerprinting, which consists of more than one chromatographic fingerprint and represents the whole characteristics of chemical constitutions of the complex medicine, is proposed as a potential strategy in this complicated case. As a typical example, a binary chromatographic fingerprinting of 'Danshen Dropping Pill' (DSDP), the best-sold traditional Chinese medicine in China, was developed. First, two HPLC fingerprints that, respectively, represent chemical characteristics of depsides and saponins of DSDP were developed, which were used to construct binary chromatographic fingerprints of DSDP. Moreover, the authentication and validation of the binary fingerprints were performed. Then, a data-level information fusion method was employed to capture the chemical information encoded in two chromatographic fingerprints. Based on the fusion results, the lot-to-lot consistency and frauds can be determined either using similarity measure or by chemometrics approach. The application of binary chromatographic fingerprinting to consistency assessment and frauds detection of DSDP clearly demonstrated that the proposed method was a powerful approach to quality control of complex herbal medicines
10. Effectiveness of energy conservation management on fatigue and participation in multiple sclerosis: A randomized controlled trial.
Blikman, Lyan Jm; van Meeteren, Jetty; Twisk, Jos Wr; de Laat, Fred Aj; de Groot, Vincent; Beckerman, Heleen; Stam, Henk J; Bussmann, Johannes Bj
2017-10-01
Fatigue is a frequently reported and disabling symptom in multiple sclerosis (MS). To investigate the effectiveness of an individual energy conservation management (ECM) intervention on fatigue and participation in persons with primary MS-related fatigue. A total of 86 severely fatigued and ambulatory adults with a definite diagnosis of MS were randomized in a single-blind, two-parallel-arm randomized clinical trial to the ECM group or the information-only control group in outpatient rehabilitation departments. Blinded assessments were carried out at baseline and at 8, 16, 26 and 52 weeks after randomization. Primary outcomes were fatigue (fatigue subscale of Checklist Individual Strength - CIS20r) and participation (Impact on Participation and Autonomy scale - IPA). Modified intention-to-treat analysis was based on 76 randomized patients (ECM, n = 36; MS nurse, n=40). No significant ECM effects were found for fatigue (overall difference CIS20r between the groups = -0.81; 95% confidence interval (CI), -3.71 to 2.11) or for four out of five IPA domains. An overall unfavourable effect was found in the ECM group for the IPA domain social relations (difference between the groups = 0.19; 95% CI, 0.03 to 0.35). The individual ECM format used in this study did not reduce MS-related fatigue and restrictions in participation more than an information-only control condition.
11. ALGORITM PENTRU DETERMINAREA STRATEGIILOR OPTIME STAŢIONARE ÎN PROBLEMELE STOCASTICE DE CONTROL OPTIMAL DISCRET PE REŢELE DECIZIONALE CU MULTIPLE CLASE RECURENTE
Maria CAPCELEA
2015-12-01
Full Text Available Este elaborat şi argumentat teoretic un algoritm eficient pentru determinarea strategiilor optime staţionare în proble-mele stocastice de control optimal discret cu perioada de dirijare infinită, definite pe reţele decizionale cu multiple clase recurente, în care este aplicat criteriul de optimizare a combinaţiei convexe a costurilor medii în clasele recurente. Sunt examinate probleme în care costurile de tranziţie între stările sistemului dinamic şi probabilităţile de tranziţie, definite în stările necontrolabile, sunt constante independente de timp. Algoritmul elaborat este bazat pe modelul de programare liniară pentru determinarea strategiilor optime în problemele de control definite pe reţele decizionale perfecte [3,4].AN ALGORITHM FOR DETERMINING STATIONARY OPTIMAL STRATEGIES FOR STOCHASTIC DISCRETE OPTIMAL CONTROL PROBLEMS DEFINED ON NETWORKS WITH MULTIPLE RECURRENT CLASSESAn efficient algorithm for determining optimal stationary strategies for the stochastic discrete optimal control problems with infinite time horizon is developed and theoretically justified. The problems are defined on decision networks with multiple recurrent classes. The average costs convex combination optimization criterion is applied. We examine problems in which the costs of transitions between the states of the dynamic system and transition probabilities, defined on the uncontrollable states, are constants independent on time. The algorithm is based on the linear programming model developed for determining optimal strategies in control problems defined on perfect decision networks [3,4].
12. Independent exercise for glottal incompetence to improve vocal problems and prevent aspiration pneumonia in the elderly: a randomized controlled trial.
Fujimaki, Yoko; Tsunoda, Koichi; Kobayashi, Rika; Tonghyo, Chong; Tanaka, Fujinobu; Kuroda, Hiroyuki; Numata, Tsutomu; Ishii, Toyota; Kuroda, Reiko; Masuda, Sawako; Hashimoto, Sho; Misawa, Hayato; Shindo, Naoko; Mori, Takahiro; Mori, Hiroko; Uchiyama, Naoki; Kamei, Yuichirou; Tanaka, Masashi; Hamaya, Hironobu; Funatsuki, Shingo; Usui, Satoko; Ito, Ikuno; Hamada, Kohei; Shindo, Akihito; Tokumaru, Yutaka; Morita, Yoko; Ueha, Rumi; Nito, Takaharu; Kikuta, Shu; Sekimoto, Sotaro; Kondo, Kenji; Sakamoto, Takashi; Itoh, Kenji; Yamasoba, Tatsuya; Matsumoto, Sumio
2017-08-01
To evaluate the effect of a self-controlled vocal exercise in elderly people with glottal closure insufficiency. Parallel-arm, individual randomized controlled trial. Patients who visited one of 10 medical centers under the National Hospital Organization group in Japan for the first time, aged 60 years or older, complaining of aspiration or hoarseness, and endoscopically confirmed to have glottal closure insufficiency owing to vocal cord atrophy, were enrolled in this study. They were randomly assigned to an intervention or a control group. The patients of the intervention group were given guidance and a DVD about a self-controlled vocal exercise. The maximum phonation time which is a measure of glottal closure was evaluated, and the number of patients who developed pneumonia during the six months was compared between the two groups. Of the 543 patients enrolled in this trial, 259 were allocated into the intervention group and 284 into the control; 60 of the intervention group and 75 of the control were not able to continue the trial. A total of 199 patients (age 73.9 ±7.25 years) in the intervention group and 209 (73.3 ±6.68 years) in the control completed the six-month trial. Intervention of the self-controlled vocal exercise extended the maximum phonation time significantly ( p < 0.001). There were two hospitalizations for pneumonia in the intervention group and 18 in the control group, representing a significant difference ( p < 0.001). The self-controlled vocal exercise allowed patients to achieve vocal cord adduction and improve glottal closure insufficiency, which reduced the rate of hospitalization for pneumonia significantly. gov Identifier-UMIN000015567.
13. Continuous Steering Stability Control Based on an Energy-Saving Torque Distribution Algorithm for a Four in-Wheel-Motor Independent-Drive Electric Vehicle
Li Zhai
2018-02-01
Full Text Available In this paper, a continuous steering stability controller based on an energy-saving torque distribution algorithm is proposed for a four in-wheel-motor independent-drive electric vehicle (4MIDEV to improve the energy consumption efficiency while maintaining the stability in steering maneuvers. The controller is designed as a hierarchical structure, including the reference model level, the upper-level controller, and the lower-level controller. The upper-level controller adopts the direct yaw moment control (DYC, which is designed to work continuously during the steering maneuver to better ensure steering stability in extreme situations, rather than working only after the vehicle is judged to be unstable. An adaptive two-hierarchy energy-saving torque distribution algorithm is developed in the lower-level controller with the friction ellipse constraint as a basis for judging whether the algorithm needs to be switched, so as to achieve a more stable and energy-efficient steering operation. The proposed stability controller was validated in a co-simulation of CarSim and Matlab/Simulink. The simulation results under different steering maneuvers indicate that the proposed controller, compared with the conventional servo controller and the ordinary continuous controller, can reduce energy consumption up to 23.68% and improve the vehicle steering stability.
14. Treatment of depressive disorders in primary care - protocol of a multiple treatment systematic review of randomized controlled trials
Linde Klaus
2011-11-01
placebo, but also how the treatment options compare to each other. Therefore, we believe that a multiple treatment systematic review of primary-care based randomized controlled trials on the most important therapies against depression is timely.
15. Multiple hereditary exostoses and ischiofemoral impingement: a case-control study
Yoong, Philip; Mansour, Ramy; Teh, James L.
2014-01-01
To assess whether there is a significant difference in the ischiofemoral space in patients with multiple hereditary exostoses affecting the proximal femora compared to normal patients. Ischiofemoral impingement is an increasingly recognized cause of hip and buttock pain. This causes narrowing of the ischiofemoral space resulting in an abnormal quadratus femoris muscle. We performed a retrospective search for individuals with MHE with proximal femoral involvement on pelvic MRI over a 7-year period (2006-2013). Suitable patients were age- and sex-matched with a control group. The minimum ischiofemoral space (MIFS) was recorded in each hip, as was the presence of edema and atrophy of quadratus femoris and concomitant hip osteoarthrosis. MRI features suggestive of ischiofemoral impingement were defined as MIFS less than 10 mm or an abnormal quadratus femoris muscle. Twenty-one hips in 11 individuals with MHE were included in the study. A total of 42 hips were analyzed. The mean age was 37 years (range, 13-72 years) and 55 % were male. There was a significant difference (p < 0.05) in the MIHS in individuals with MHE (mean, 10.7 mm, range, 0-21 mm) compared to a control group (mean, 18.1 mm, range, 10.5-26.5 mm). MRI features suggestive of ischiofemoral impingement were seen in 13/21 (62 %) hips in the MHE group and 0/21 (0 %) in the control group. The reduced ischiofemoral space and associated quadratus femoris abnormalities in patients with MHE involving the proximal femora may account for hip/buttock symptoms in the absence of significant degenerative change. (orig.)
16. Context, emotion, and the strategic pursuit of goals: Interactions among multiple brain systems controlling motivated behaviour
Aaron J Gruber
2012-08-01
Full Text Available Motivated behaviour exhibits properties that change with experience and partially dissociate among a number of brain structures. Here, we review evidence from rodent experiments demonstrating that multiple brain systems acquire information in parallel and either cooperate or compete for behavioural control. We propose a conceptual model of systems interaction wherein a ventral emotional memory network involving ventral striatum, amygdala, ventral hippocampus, and ventromedial prefrontal cortex triages behavioural responding to stimuli according to their associated affective outcomes. This system engages autonomic and postural responding (avoiding, ignoring, approaching in accordance with associated stimulus valence (negative, neutral, positive, but does not engage particular operant responses. Rather, this emotional system suppresses or invigorates actions that are selected through competition between goal-directed control involving dorsomedial striatum and habitual control involving dorsolateral striatum. The hippocampus provides contextual specificity to the emotional system, and provides an information rich input to the goal-directed system for navigation and discriminations involving ambiguous contexts, complex sensory configurations, or temporal ordering. The rapid acquisition and high capacity for episodic associations in the emotional system may unburden the more complex goal-directed system and reduce interference in the habit system from processing contingencies of neutral stimuli. Interactions among these systems likely involve inhibitory mechanisms and neuromodulation in the basal ganglia to form a dominant response strategy. Innate traits, training methods, and task demands contribute to the nature of these interactions, which can include incidental learning in non-dominant systems. Addition of these features to reinforcement learning models of decision making may better align theoretical predictions with behavioural and neural
17. Impact of Pilates Exercise in Multiple Sclerosis: A Randomized Controlled Trial.
Duff, Whitney R D; Andrushko, Justin W; Renshaw, Doug W; Chilibeck, Philip D; Farthing, Jonathan P; Danielson, Jana; Evans, Charity D
2018-01-01
Pilates is a series of exercises based on whole-body movement and may improve mobility in people with multiple sclerosis (MS). The purpose of this study was to determine the effect of Pilates on walking performance in people with MS. 30 individuals with MS who were not restricted to a wheelchair or scooter (Patient-Determined Disease Steps scale score Pilates (twice weekly) and massage therapy (once weekly) or once-weekly massage therapy only (control group). The Pilates was delivered in a group setting (five to ten participants per session). The primary outcome was change in walking performance (6-Minute Walk Test) after 12 weeks. Secondary outcomes included functional ability (Timed Up and Go test), balance (Fullerton Advanced Balance Scale), flexibility (sit and reach test), body composition (dual-energy X-ray absorptiometry), core endurance (plank-hold test), and muscle strength and voluntary activation (quadriceps). Intention-to-treat analysis was performed using a two-factor repeated-measures analysis of variance. Walking distance increased by a mean (SD) of 52.4 (40.2) m in the Pilates group versus 15.0 (34.1) m in the control group (group × time, P = .01). Mean (SD) time to complete the Timed Up and Go test decreased by 1.5 (2.8) seconds in the Pilates group versus an increase of 0.3 (0.9) seconds in the control group (group × time, P = .03). There were no other significant differences between groups over time. Pilates improved walking performance and functional ability in persons with MS and is a viable exercise option to help manage the disease.
18. False discovery rate control incorporating phylogenetic tree increases detection power in microbiome-wide multiple testing.
Xiao, Jian; Cao, Hongyuan; Chen, Jun
2017-09-15
Next generation sequencing technologies have enabled the study of the human microbiome through direct sequencing of microbial DNA, resulting in an enormous amount of microbiome sequencing data. One unique characteristic of microbiome data is the phylogenetic tree that relates all the bacterial species. Closely related bacterial species have a tendency to exhibit a similar relationship with the environment or disease. Thus, incorporating the phylogenetic tree information can potentially improve the detection power for microbiome-wide association studies, where hundreds or thousands of tests are conducted simultaneously to identify bacterial species associated with a phenotype of interest. Despite much progress in multiple testing procedures such as false discovery rate (FDR) control, methods that take into account the phylogenetic tree are largely limited. We propose a new FDR control procedure that incorporates the prior structure information and apply it to microbiome data. The proposed procedure is based on a hierarchical model, where a structure-based prior distribution is designed to utilize the phylogenetic tree. By borrowing information from neighboring bacterial species, we are able to improve the statistical power of detecting associated bacterial species while controlling the FDR at desired levels. When the phylogenetic tree is mis-specified or non-informative, our procedure achieves a similar power as traditional procedures that do not take into account the tree structure. We demonstrate the performance of our method through extensive simulations and real microbiome datasets. We identified far more alcohol-drinking associated bacterial species than traditional methods. R package StructFDR is available from CRAN. chen.jun2@mayo.edu. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com
19. Multiple hereditary exostoses and ischiofemoral impingement: a case-control study
Yoong, Philip; Mansour, Ramy; Teh, James L. [Nuffield Orthopaedic Centre, Department of Radiology, Oxford (United Kingdom)
2014-09-15
To assess whether there is a significant difference in the ischiofemoral space in patients with multiple hereditary exostoses affecting the proximal femora compared to normal patients. Ischiofemoral impingement is an increasingly recognized cause of hip and buttock pain. This causes narrowing of the ischiofemoral space resulting in an abnormal quadratus femoris muscle. We performed a retrospective search for individuals with MHE with proximal femoral involvement on pelvic MRI over a 7-year period (2006-2013). Suitable patients were age- and sex-matched with a control group. The minimum ischiofemoral space (MIFS) was recorded in each hip, as was the presence of edema and atrophy of quadratus femoris and concomitant hip osteoarthrosis. MRI features suggestive of ischiofemoral impingement were defined as MIFS less than 10 mm or an abnormal quadratus femoris muscle. Twenty-one hips in 11 individuals with MHE were included in the study. A total of 42 hips were analyzed. The mean age was 37 years (range, 13-72 years) and 55 % were male. There was a significant difference (p < 0.05) in the MIHS in individuals with MHE (mean, 10.7 mm, range, 0-21 mm) compared to a control group (mean, 18.1 mm, range, 10.5-26.5 mm). MRI features suggestive of ischiofemoral impingement were seen in 13/21 (62 %) hips in the MHE group and 0/21 (0 %) in the control group. The reduced ischiofemoral space and associated quadratus femoris abnormalities in patients with MHE involving the proximal femora may account for hip/buttock symptoms in the absence of significant degenerative change. (orig.)
20. Muscle Synergies Control during Hand-Reaching Tasks in Multiple Directions Post-stroke
Sharon Israely
2018-02-01
Full Text Available Purpose: A muscle synergies model was suggested to represent a simplifying motor control mechanism by the brainstem and spinal cord. The aim of the study was to investigate the feasibility of such control mechanisms in the rehabilitation of post-stroke individuals during the execution of hand-reaching movements in multiple directions, compared to non-stroke individuals.Methods: Twelve non-stroke and 13 post-stroke individuals participated in the study. Muscle synergies were extracted from EMG data that was recorded during hand reaching tasks, using the NMF algorithm. The optimal number of synergies was evaluated in both groups using the Variance Accounted For (VAF and the Mean Squared Error (MSE. A cross validation procedure was carried out to define a representative set of synergies. The similarity index and the K-means algorithm were applied to validate the existence of such a set of synergies, but also to compare the modulation properties of synergies for different movement directions between groups. The similarity index and hierarchical cluster analysis were also applied to compare between group synergies.Results: Four synergies were chosen to optimally capture the variances in the EMG data, with mean VAF of 0.917 ± 0.034 and 0.883 ± 0.046 of the data variances, with respective MSE of 0.007 and 0.016, in the control and study groups, respectively. The representative set of synergies was set to be extracted from movement to the center of the reaching space. Two synergies had different muscle activation balance between groups. Seven and 17 clusters partitioned the muscle synergies of the control and study groups. The control group exhibited a gradual change in the activation in the amplitude in the time domain (modulation of synergies, as reflected by the similarity index, whereas the study group exhibited consistently significant differences between all movement directions and the representative set of synergies. The study findings support
1. A retrospective likelihood approach for efficient integration of multiple omics factors in case-control association studies.
Balliu, Brunilda; Tsonaka, Roula; Boehringer, Stefan; Houwing-Duistermaat, Jeanine
2015-03-01
Integrative omics, the joint analysis of outcome and multiple types of omics data, such as genomics, epigenomics, and transcriptomics data, constitute a promising approach for powerful and biologically relevant association studies. These studies often employ a case-control design, and often include nonomics covariates, such as age and gender, that may modify the underlying omics risk factors. An open question is how to best integrate multiple omics and nonomics information to maximize statistical power in case-control studies that ascertain individuals based on the phenotype. Recent work on integrative omics have used prospective approaches, modeling case-control status conditional on omics, and nonomics risk factors. Compared to univariate approaches, jointly analyzing multiple risk factors with a prospective approach increases power in nonascertained cohorts. However, these prospective approaches often lose power in case-control studies. In this article, we propose a novel statistical method for integrating multiple omics and nonomics factors in case-control association studies. Our method is based on a retrospective likelihood function that models the joint distribution of omics and nonomics factors conditional on case-control status. The new method provides accurate control of Type I error rate and has increased efficiency over prospective approaches in both simulated and real data. © 2015 Wiley Periodicals, Inc.
2. Time-varying motor control of autotomized leopard gecko tails: multiple inputs and behavioral modulation.
Higham, Timothy E; Russell, Anthony P
2012-02-01
Autotomy (voluntary loss of an appendage) is common among diverse groups of vertebrates and invertebrates, and much attention has been given to ecological and developmental aspects of tail autotomy in lizards. Although most studies have focused on the ramifications for the lizard (behavior, biomechanics, energetics, etc.), the tail itself can exhibit interesting behaviors once segregated from the body. For example, recent work highlighted the ability of leopard gecko tails to jump and flip, in addition to being able to swing back and forth. Little is known, however, about the control mechanisms underlying these movements. Using electromyography, we examined the time-varying in vivo motor patterns at four sites (two proximal and two distal) in the tail of the leopard gecko, Eublepharis macularius, following autotomy. Using these data we tested the hypothesis that the disparity in movements results simply from overlapping pattern generators within the tail. We found that burst duration, but not cycle duration, of the rhythmic swings reached a plateau at approximately 150 s following autotomy. This is likely because of physiological changes related to muscle fatigue and ischemia. For flips and jumps, burst and cycle duration exhibited no regular pattern. The coefficient of variation in motor patterns was significantly greater for jumps and flips than for rhythmic swings. This supports the conclusion that the different tail behaviors do not stem from overlapping pattern generators, but that they rely upon independent neural circuits. The signal controlling jumps and flips may be modified by sensory information from the environment. Finally, we found that jumps and flips are initiated using relatively synchronous activity between the two sides of the tail. In contrast, alternating activation of the right and left sides of the tail result in rhythmic swings. The mechanism underlying this change in tail behavior is comparable to locomotor gait changes in vertebrates.
3. Control Demonstration of Multiple Doubly-Fed Induction Motors for Hybrid Electric Propulsion
Sadey, David J.; Bodson, Marc; Csank, Jeffrey T.; Hunker, Keith R.; Theman, Casey J.; Taylor, Linda M.
2017-01-01
The Convergent Aeronautics Solutions (CAS) High Voltage-Hybrid Electric Propulsion (HVHEP) task was formulated to support the move into future hybrid-electric aircraft. The goal of this project is to develop a new AC power architecture to support the needs of higher efficiency and lower emissions. This proposed architecture will adopt the use of the doubly-fed induction machine (DFIM) for propulsor drive motor application.The Convergent Aeronautics Solutions (CAS) High Voltage-Hybrid Electric Propulsion (HVHEP) task was formulated to support the move into future hybrid-electric aircraft. The goal of this project is to develop a new AC power architecture to support the needs of higher efficiency and lower emissions. This proposed architecture will adopt the use of the doubly-fed induction machine (DFIM) for propulsor drive motor application. DFIMs are attractive for several reasons, including but not limited to the ability to self-start, ability to operate sub- and super-synchronously, and requiring only fractionally rated power converters on a per-unit basis depending on the required range of operation. The focus of this paper is based specifically on the presentation and analysis of a novel strategy which allows for independent operation of each of the aforementioned doubly-fed induction motors. This strategy includes synchronization, soft-start, and closed loop speed control of each motor as a means of controlling output thrust; be it concurrently or differentially. The demonstration of this strategy has recently been proven out on a low power test bed using fractional horsepower machines. Simulation and hardware test results are presented in the paper.
4. Control and design of multiple unmanned air vehicles for persistent surveillance
Nigam, Nikhil
Control of multiple autonomous aircraft for search and exploration, is a topic of current research interest for applications such as weather monitoring, geographical surveys, search and rescue, tactical reconnaissance, and extra-terrestrial exploration, and the need to distribute sensing is driven by considerations of efficiency, reliability, cost and scalability. Hence, this problem has been extensively studied in the fields of controls and artificial intelligence. The task of persistent surveillance is different from a coverage/exploration problem, in that all areas need to be continuously searched, minimizing the time between visitations to each region in the target space. This distinction does not allow a straightforward application of most exploration techniques to the problem, although ideas from these methods can still be used. The use of aerial vehicles is motivated by their ability to cover larger spaces and their relative insensitivity to terrain. However, the dynamics of Unmanned Air Vehicles (UAVs) adds complexity to the control problem. Most of the work in the literature decouples the vehicle dynamics and control policies, but their interaction is particularly interesting for a surveillance mission. Stochastic environments and UAV failures further enrich the problem by requiring the control policies to be robust, and this aspect is particularly important for hardware implementations. For a persistent mission, it becomes imperative to consider the range/endurance constraints of the vehicles. The coupling of the control policy with the endurance constraints of the vehicles is an aspect that has not been sufficiently explored. Design of UAVs for desirable mission performance is also an issue of considerable significance. The use of a single monolithic optimization for such a problem has practical limitations, and decomposition-based design is a potential alternative. In this research high-level control policies are devised, that are scalable, reliable
5. Dual dimensionality reduction reveals independent encoding of motor features in a muscle synergy for insect flight control.
Sponberg, Simon; Daniel, Thomas L; Fairhall, Adrienne L
2015-04-01
What are the features of movement encoded by changing motor commands? Do motor commands encode movement independently or can they be represented in a reduced set of signals (i.e. synergies)? Motor encoding poses a computational and practical challenge because many muscles typically drive movement, and simultaneous electrophysiology recordings of all motor commands are typically not available. Moreover, during a single locomotor period (a stride or wingstroke) the variation in movement may have high dimensionality, even if only a few discrete signals activate the muscles. Here, we apply the method of partial least squares (PLS) to extract the encoded features of movement based on the cross-covariance of motor signals and movement. PLS simultaneously decomposes both datasets and identifies only the variation in movement that relates to the specific muscles of interest. We use this approach to explore how the main downstroke flight muscles of an insect, the hawkmoth Manduca sexta, encode torque during yaw turns. We simultaneously record muscle activity and turning torque in tethered flying moths experiencing wide-field visual stimuli. We ask whether this pair of muscles acts as a muscle synergy (a single linear combination of activity) consistent with their hypothesized function of producing a left-right power differential. Alternatively, each muscle might individually encode variation in movement. We show that PLS feature analysis produces an efficient reduction of dimensionality in torque variation within a wingstroke. At first, the two muscles appear to behave as a synergy when we consider only their wingstroke-averaged torque. However, when we consider the PLS features, the muscles reveal independent encoding of torque. Using these features we can predictably reconstruct the variation in torque corresponding to changes in muscle activation. PLS-based feature analysis provides a general two-sided dimensionality reduction that reveals encoding in high dimensional
6. Dual dimensionality reduction reveals independent encoding of motor features in a muscle synergy for insect flight control.
Simon Sponberg
2015-04-01
Full Text Available What are the features of movement encoded by changing motor commands? Do motor commands encode movement independently or can they be represented in a reduced set of signals (i.e. synergies? Motor encoding poses a computational and practical challenge because many muscles typically drive movement, and simultaneous electrophysiology recordings of all motor commands are typically not available. Moreover, during a single locomotor period (a stride or wingstroke the variation in movement may have high dimensionality, even if only a few discrete signals activate the muscles. Here, we apply the method of partial least squares (PLS to extract the encoded features of movement based on the cross-covariance of motor signals and movement. PLS simultaneously decomposes both datasets and identifies only the variation in movement that relates to the specific muscles of interest. We use this approach to explore how the main downstroke flight muscles of an insect, the hawkmoth Manduca sexta, encode torque during yaw turns. We simultaneously record muscle activity and turning torque in tethered flying moths experiencing wide-field visual stimuli. We ask whether this pair of muscles acts as a muscle synergy (a single linear combination of activity consistent with their hypothesized function of producing a left-right power differential. Alternatively, each muscle might individually encode variation in movement. We show that PLS feature analysis produces an efficient reduction of dimensionality in torque variation within a wingstroke. At first, the two muscles appear to behave as a synergy when we consider only their wingstroke-averaged torque. However, when we consider the PLS features, the muscles reveal independent encoding of torque. Using these features we can predictably reconstruct the variation in torque corresponding to changes in muscle activation. PLS-based feature analysis provides a general two-sided dimensionality reduction that reveals encoding in
7. An independent monitor unit calculation by commercial software as a part of a radiotherapy treatment planning system quality control
Nechvil, K.; Mynarik, J.
2014-01-01
For the independent calculation of the monitored unit (MU) the commercial software RadCalc (Lifeline Software Inc., Tyler TX) was used as the choice of some available similar programs. The program was configured and used to verify the doses calculated by commercially accessible planning system Eclipse version 8.6.17 (Varian Medical System Inc., Palo Alto). This system is being used during the clinical running for the creation of the treatment plans. The results of each plan were compared to the dose phantom measurements by the ionization chamber at the same point in which the calculation were done (Eclipse, RadCalc) - in the izocentre. TPS is configured by the beam data (PDD and OAR). Those beam data were exported and afterwards the same data were imported to the program RadCalc. The consistent and independent data between TPS and RadCalc were gained by this process. The reference conditions were set the identical in RadCalc as in TPS, so the consistency between TPS and RadCalc output factors has been achieved (Collimator Scatter Factor: Sc, Phantom Scatter Factor: Sp). Those output factors were also measured by the ionizing chamber in the water phantom and compared with the TPS. Based on the clinical data of the response to the doses, ICRU recommends ensuring the ability of dosimetric systems to deliver the doses with accuracy of at least 5%. Many factors, such as layout of anatomic structures, positioning of a patient, factors related to an accelerator (a dose calibration and mechanic parameters) cause random and systematic failures in a dose delivery. The source of some problems can be also caused by the system databases and relating information transfer; and the TPS containing besides other things other dose calculation algorithms. (authors)
8. Dual Dimensionality Reduction Reveals Independent Encoding of Motor Features in a Muscle Synergy for Insect Flight Control
Sponberg, Simon; Daniel, Thomas L.; Fairhall, Adrienne L.
2015-01-01
What are the features of movement encoded by changing motor commands? Do motor commands encode movement independently or can they be represented in a reduced set of signals (i.e. synergies)? Motor encoding poses a computational and practical challenge because many muscles typically drive movement, and simultaneous electrophysiology recordings of all motor commands are typically not available. Moreover, during a single locomotor period (a stride or wingstroke) the variation in movement may have high dimensionality, even if only a few discrete signals activate the muscles. Here, we apply the method of partial least squares (PLS) to extract the encoded features of movement based on the cross-covariance of motor signals and movement. PLS simultaneously decomposes both datasets and identifies only the variation in movement that relates to the specific muscles of interest. We use this approach to explore how the main downstroke flight muscles of an insect, the hawkmoth Manduca sexta, encode torque during yaw turns. We simultaneously record muscle activity and turning torque in tethered flying moths experiencing wide-field visual stimuli. We ask whether this pair of muscles acts as a muscle synergy (a single linear combination of activity) consistent with their hypothesized function of producing a left-right power differential. Alternatively, each muscle might individually encode variation in movement. We show that PLS feature analysis produces an efficient reduction of dimensionality in torque variation within a wingstroke. At first, the two muscles appear to behave as a synergy when we consider only their wingstroke-averaged torque. However, when we consider the PLS features, the muscles reveal independent encoding of torque. Using these features we can predictably reconstruct the variation in torque corresponding to changes in muscle activation. PLS-based feature analysis provides a general two-sided dimensionality reduction that reveals encoding in high dimensional
9. Paper-Based Digital Microfluidic Chip for Multiple Electrochemical Assay Operated by a Wireless Portable Control System
Ruecha, Nipapan; Lee, Jumi; Chae, Heedo
2017-01-01
for multiple analysis assays are fabricated by affordable printing techniques. For enhanced sensitivity of the sensor, the working electrode is modified through the electrochemical method, namely by reducing graphene with voltammetry and coating gold nanoparticles by amperometry. Detachable sensor and absorber...... designed portable power supply and wireless control system, the active paper-based chip platform can be utilized as an advanced point-of-care device for multiple assays in digital microfluidics....
10. Report: State of Washington Water Pollution Control State Revolving Fund Financial Statements with Independent Auditor's Report, June 30, 2003
Report #2004-1-00067, May 26, 2004. The financial statements referred to in the first paragraph present fairly the financial position of the Washington Department of Ecology Water Pollution Control State Revolving Fund as of June 30, 2003.
11. Multiple component patient safety intervention in English hospitals: controlled evaluation of second phase.
Benning, Amirta; Dixon-Woods, Mary; Nwulu, Ugochi; Ghaleb, Maisoon; Dawson, Jeremy; Barber, Nick; Franklin, Bryony Dean; Girling, Alan; Hemming, Karla; Carmalt, Martin; Rudge, Gavin; Naicker, Thirumalai; Kotecha, Amit; Derrington, M Clare; Lilford, Richard
2011-02-03
To independently evaluate the impact of the second phase of the Health Foundation's Safer Patients Initiative (SPI2) on a range of patient safety measures. Design A controlled before and after design. Five substudies: survey of staff attitudes; review of case notes from high risk (respiratory) patients in medical wards; review of case notes from surgical patients; indirect evaluation of hand hygiene by measuring hospital use of handwashing materials; measurement of outcomes (adverse events, mortality among high risk patients admitted to medical wards, patients' satisfaction, mortality in intensive care, rates of hospital acquired infection). Setting NHS hospitals in England. Nine hospitals participating in SPI2 and nine matched control hospitals. The SPI2 intervention was similar to the SPI1, with somewhat modified goals, a slightly longer intervention period, and a smaller budget per hospital. One of the scores (organisational climate) showed a significant (P = 0.009) difference in rate of change over time, which favoured the control hospitals, though the difference was only 0.07 points on a five point scale. Results of the explicit case note reviews of high risk medical patients showed that certain practices improved over time in both control and SPI2 hospitals (and none deteriorated), but there were no significant differences between control and SPI2 hospitals. Monitoring of vital signs improved across control and SPI2 sites. This temporal effect was significant for monitoring the respiratory rate at both the six hour (adjusted odds ratio 2.1, 99% confidence interval 1.0 to 4.3; P = 0.010) and 12 hour (2.4, 1.1 to 5.0; P = 0.002) periods after admission. There was no significant effect of SPI for any of the measures of vital signs. Use of a recommended system for scoring the severity of pneumonia improved from 1.9% (1/52) to 21.4% (12/56) of control and from 2.0% (1/50) to 41.7% (25/60) of SPI2 patients. This temporal change was significant (7.3, 1.4 to 37.7; P
12. Multiple component patient safety intervention in English hospitals: controlled evaluation of second phase
Benning, Amirta; Dixon-Woods, Mary; Nwulu, Ugochi; Ghaleb, Maisoon; Dawson, Jeremy; Barber, Nick; Franklin, Bryony Dean; Girling, Alan; Hemming, Karla; Carmalt, Martin; Rudge, Gavin; Naicker, Thirumalai; Kotecha, Amit; Derrington, M Clare
2011-01-01
Objective To independently evaluate the impact of the second phase of the Health Foundation’s Safer Patients Initiative (SPI2) on a range of patient safety measures. Design A controlled before and after design. Five substudies: survey of staff attitudes; review of case notes from high risk (respiratory) patients in medical wards; review of case notes from surgical patients; indirect evaluation of hand hygiene by measuring hospital use of handwashing materials; measurement of outcomes (adverse events, mortality among high risk patients admitted to medical wards, patients’ satisfaction, mortality in intensive care, rates of hospital acquired infection). Setting NHS hospitals in England. Participants Nine hospitals participating in SPI2 and nine matched control hospitals. Intervention The SPI2 intervention was similar to the SPI1, with somewhat modified goals, a slightly longer intervention period, and a smaller budget per hospital. Results One of the scores (organisational climate) showed a significant (P=0.009) difference in rate of change over time, which favoured the control hospitals, though the difference was only 0.07 points on a five point scale. Results of the explicit case note reviews of high risk medical patients showed that certain practices improved over time in both control and SPI2 hospitals (and none deteriorated), but there were no significant differences between control and SPI2 hospitals. Monitoring of vital signs improved across control and SPI2 sites. This temporal effect was significant for monitoring the respiratory rate at both the six hour (adjusted odds ratio 2.1, 99% confidence interval 1.0 to 4.3; P=0.010) and 12 hour (2.4, 1.1 to 5.0; P=0.002) periods after admission. There was no significant effect of SPI for any of the measures of vital signs. Use of a recommended system for scoring the severity of pneumonia improved from 1.9% (1/52) to 21.4% (12/56) of control and from 2.0% (1/50) to 41.7% (25/60) of SPI2 patients. This temporal
13. Change in body fat mass is independently associated with executive functions in older women: a secondary analysis of a 12-month randomized controlled trial.
Elizabeth Dao
Full Text Available OBJECTIVES: To investigate the independent contribution of change in sub-total body fat and lean mass to cognitive performance, specifically the executive processes of selective attention and conflict resolution, in community-dwelling older women. METHODS: This secondary analysis included 114 women aged 65 to 75 years old. Participants were randomly allocated to once-weekly resistance training, twice-weekly resistance training, or twice-weekly balance and tone training. The primary outcome measure was the executive processes of selective attention and conflict resolution as assessed by the Stroop Test. Sub-total body fat and lean mass were measured by dual-energy x-ray absorptiometry (DXA to determine the independent association of change in both sub-total body fat and sub-total body lean mass with Stroop Test performance at trial completion. RESULTS: A multiple linear regression model showed reductions in sub-total body fat mass to be independently associated with better performance on the Stroop Test at trial completion after accounting for baseline Stroop performance, age, baseline global cognitive state, baseline number of comorbidities, baseline depression, and experimental group. The total variance explained was 39.5%; change in sub-total body fat mass explained 3.9% of the variance. Change in sub-total body lean mass was not independently associated with Stroop Test performance (P>0.05. CONCLUSION: Our findings suggest that reductions in sub-total body fat mass - not sub-total lean mass - is associated with better performance of selective attention and conflict resolution.
14. The BDNF Val66Met polymorphism has opposite effects on memory circuits of multiple sclerosis patients and controls.
Francesco Fera
Full Text Available Episodic memory deficits are frequent symptoms in Multiple Sclerosis and have been associated with dysfunctions of the hippocampus, a key region for learning. However, it is unclear whether genetic factors that influence neural plasticity modulate episodic memory in MS. We thus studied how the Brain Derived Neurotrophic Factor Val(66Met genotype, a common polymorphism influencing the hippocampal function in healthy controls, impacted on brain networks underlying episodic memory in patients with Multiple Sclerosis. Functional magnetic resonance imaging was used to assess how the Brain Derived Neurotrophic Factor Val(66Met polymorphism modulated brain regional activity and functional connectivity in 26 cognitively unimpaired Multiple Sclerosis patients and 25 age- and education-matched healthy controls while performing an episodic memory task that included encoding and retrieving visual scenes. We found a highly significant group by genotype interaction in the left posterior hippocampus, bilateral parahippocampus, and left posterior cingulate cortex. In particular, Multiple Sclerosis patients homozygous for the Val(66 allele, relative to Met(66 carriers, showed greater brain responses during both encoding and retrieval while the opposite was true for healthy controls. Furthermore, a robust group by genotype by task interaction was detected for the functional connectivity between the left posterior hippocampus and the ipsilateral posterior cingulate cortex. Here, greater hippocampus-posterior cingulate cortex connectivity was observed in Multiple Sclerosis Met(66 carriers relative to Val(66 homozygous during retrieval (but not encoding while, again, the reverse was true for healthy controls. The Val(66Met polymorphism has opposite effects on hippocampal circuitry underlying episodic memory in Multiple Sclerosis patients and healthy controls. Enhancing the knowledge of how genetic factors influence cognitive functions may improve the clinical
15. Food and dietary patterns and multiple sclerosis: a case-control study in Belgrade (Serbia
Tatjana D. Pekmezovic
2009-03-01
Full Text Available
Background: The aetiology of multiple sclerosis (MS is unclear, but numerous studies suggest that different exogenous factors can lead to the development of the disease in genetically susceptible individuals. The objective of this case-control study was to determine the role of food and dietary patterns in patients with MS in the population of Belgrade (Serbia.
Methods: In this matched case-control study, we included 110 cases with definite MS according to McDonald’s criteria, in whom the onset symptoms occurred up to 2 years prior to the interview, who were followed-up at the Institute of Neurology, Clinical Centre of Serbia, Belgrade. The identical number of controls from the same institution, individually matched by sex, age and area of residence, was recruited from patients with various non-autoimmune neurological disorders. Dietary information was obtained by using a frequency history approach.
Results: According to univariate conditional logistic regression analysis the following factors were significantly related to MS: body mass index (BMI less than 25 (OR=2.2, p=0.009, frequent consumption of beef (OR=1.7, p=0.043, chicken (OR=2.0, p=0.045, meat of the lamb (OR=2.1, p=0.013, butter (OR=1.7, p=0.056 and ice-cream (OR=1.8, p=0.031, with dose-response relationship. Consumption of majority of various fruit was more frequently reported by controls. According to multivariate conditional logistic regression analysis, BMI less than 25 (OR=2.3, p=0.008, consumption (weekly of beef (OR=2.0, p=0.017 and butter (OR=1.9, p=0.027 was significantly related to MS, while regular consumption of cherry (OR=0.4, p=0.024 had protective role.
Conclusions: This study might assist in potential defining of the dietary factors that could contribute to the risk of developing MS.
16. Environmental risk factors in the aetiology of multiple sclerosis in Kayseri: a case control study
Servin Yeşil Günal
2013-06-01
Full Text Available Background: our purpose is to evaluate the possible relationship between multiple sclerosis (MS and environmental factors in Kayseri.Methods: this case control study was conducted on 100 patients with MS and 100 sex-aged and residential area matched control. Data was collected by using face to face interviews. Questionnaire consisted of two parts. The first part was comprised of items related with the participants’ sociodemographic features. The second part was related with factors thought to be involved in the occurrence or aggravation of the disease. The Chi-square test and logistic regression were used for analysis.Results: logistic regression analysis revealed the following as possible risk factors in MS cases: economic status (Odds Ratio (OR: 0.14 adjusted 7.19; Confidence Interval 95% (CI: 0.05-0.43, having a sensitive personality (OR:4.51; 95% CI: 1.10-18.45, familial history of MS (OR:3.28; 95% CI: 1.3-8.27, history of cranial and spinal injury (OR: 2.99; 95% CI: 1.11-8.08, cooking oil consumption (OR:0.07 adjusted 13.5; 95% CI: 0.03-0.20, consumption of legumes and grains (OR: 0.11 adjusted 8.9; 95% CI: 0.03-0.41, and living in dwellings within a distance of 500 meters from transformer basestations (OR: 6.5; 95% CI: 1.54-28.21.Conclusions: we believe that it is necessary to inform the individuals about the risk of MS and their relatives of the results of large-scale joint studies and to offer suggestions based on the data obtained.
17. A randomized, placebo-controlled trial of levetiracetam in central pain in multiple sclerosis
Falah, M; Madsen, C; Holbech, J V
2012-01-01
sclerosis. This was a randomized, double-blind, placebo-controlled, cross-over trial with levetiracetam 3000 mg/day versus placebo (6-week treatment periods). Patients with multiple sclerosis, symptoms and signs complying with central neuropathic pain and pain symptoms for more than 6 months, as well....... Twenty-seven patients were included in the data analysis. There were no differences in the ratings of pain relief (levetiracetam 2.4 vs. placebo 2.1, p = 0.169), total pain intensity (levetiracetam 5.3 vs. placebo 5.7, p = 0.147) or any of the other outcome measures (p = 0.086-0.715) in the total sample...... of patients. However, there was significant reduction of pain, increased pain relief and/or more favourable pain relief with levetiracetam than with placebo in patients with lancinating or without touch-evoked pain (p = 0.025-0.046). This study found no effect of the anticonvulsant levetiracetam in non...
18. [Physiotherapy and neurogenic lower urinary tract dysfunction in multiple sclerosis patients: a randomized controlled trial].
Gaspard, L; Tombal, B; Opsomer, R-J; Castille, Y; Van Pesch, V; Detrembleur, C
2014-09-01
This randomized controlled trial compare the efficacy of pelvic floor muscle training vs. transcutaneous posterior tibial nerve stimulation. Inclusion criteria were EDSS scoreurinary tract symptoms. Exclusion criteria were multiple sclerosis relapse during the study, active urinary tract infection and pregnancy. The primary outcome was quality of life (SF-Qualiveen questionnaire). Secondary outcomes included overactive bladder (USP questionnaire) score and frequency of urgency episodes (3-day bladder diary). Sample size was calculated after 18 patients were included. Data analysis was blinded. Each patient received 9 sessions of 30 minutes weekly. Patients were randomized in pelvic floor muscles exercises with biofeedback group (muscle endurance and relaxation) or transcutaneous posterior tibial nerve stimulation group (rectangular alternative biphasic current with low frequency). A total of 31 patients were included. No difference appeared between groups for quality of life, overactive bladder and frequency of urgency episodes (respectively P=0.197, P=0.532 et P=0.788). These parameters were significantly improved in pelvic floor muscle training group (n=16) (respectively P=0.004, P=0.002 et P=0.006) and in transcutaneous posterior tibial nerve stimulation group (n=15) (respectively P=0.001, P=0.001 et P=0.031). Pelvic floor muscle training and transcutaneous posterior tibial nerve stimulation improved in the same way symptoms related to urgency in MS patients with mild disability. 2. Copyright © 2014 Elsevier Masson SAS. All rights reserved.
19. Air Traffic Controller Performance and Acceptability of Multiple UAS in a Simulated NAS Environment
Vu, Kim-Phuong L.; Strybel, Thomas; Chiappe, Dan; Morales, Greg; Battiste, Vernol; Shively, Robert Jay
2014-01-01
Previously, we showed that air traffic controllers (ATCos) rated UAS pilot verbal response latencies as acceptable when a 1.5 s delay was added to the UAS pilot responses, but a 5 s delay was rated as mostly unacceptable. In the present study we determined whether a 1.5 s added delay in the UAS pilots' verbal communications would affect ATCos interactions with UAS and other conventional aircraft when the number and speed of the UAS were manipulated. Eight radar-certified ATCos participated in this simulation. The ATCos managed a medium altitude sector containing arrival aircraft, en route aircraft, and one to four UAS. The UAS were conducting a surveillance mission and flew at either a "slow" or "fast" speed. We measured both UAS and conventional pilots' verbal communication latencies, and obtained ATCos' acceptability ratings for these latencies. Although the UAS pilot response latencies were longer than those of conventional pilots, the ATCos rated UAS pilot verbal communication latencies to be as acceptable as those of conventional pilots. Because the overall traffic load within the sector was held constant, ATCos only performed slightly worse when multiple UAS were in their sector compared to when only one UAS was in the sector. Implications of these findings for UAS integration in the NAS are discussed.
20. Community integration outcomes of people with spinal cord injury and multiple matched controls: A pilot study.
Callaway, Libby; Enticott, Joanne; Farnworth, Louise; McDonald, Rachael; Migliorini, Christine; Willer, Barry
2017-06-01
Australia's National Disability Insurance Scheme (NDIS) is designed to influence home, social and economic participation for Scheme participants. Given the major disability reform underway, this pilot study aimed to: (i) examine communi | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4551536440849304, "perplexity": 7063.288949688696}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-26/segments/1560627999817.30/warc/CC-MAIN-20190625092324-20190625114324-00294.warc.gz"} |