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http://docs.chainer.org/en/latest/reference/generated/chainer.utils.type_check.expect.html | # chainer.utils.type_check.expect¶
chainer.utils.type_check.expect(*bool_exprs)[source]
Evaluates and tests all given expressions.
This function evaluates given boolean expressions in order. When at least one expression is evaluated as False, that means the given condition is not satisfied. You can check conditions with this function.
Parameters: bool_exprs (tuple of Bool expressions) – Bool expressions you want to evaluate. | {"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": 0.1653292030096054, "perplexity": 1637.217753327233}, "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-2018-30/segments/1531676589902.8/warc/CC-MAIN-20180717203423-20180717223423-00197.warc.gz"} |
http://mathematica.stackexchange.com/questions/35285/evaluating-a-smoothkerneldistribution-at-a-point | # Evaluating a SmoothKernelDistribution at a point
I would like to evaluate the value of the following SmoothKernelDistribution at the location, say, 2.35. What is the right way to do it?
data1 = {1, 2, 3};
DD = SmoothKernelDistribution[data1, 0.5];
Plot[PDF[DD, x], {x, -2, 10}]
-
You mean PDF[DD, 2.35]? – belisarius Nov 3 '13 at 6:16
pretty much yes. actually to measure the area under the curve where the values are above 2.35 – Doron Nov 3 '13 at 6:21
To "measure the area under the curve where the values are above 2.35", evalute
1. - CDF[DD, 2.35]
0.382878
This is the same as
NIntegrate[PDF[DD, x], {x, 2.35, ∞}]
0.382878
-
Just for variety also:
SurvivalFunction[DD, 2.35]
yields...
0.382878
- | {"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": 0.8612260818481445, "perplexity": 4465.597799745057}, "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/1429246658061.59/warc/CC-MAIN-20150417045738-00288-ip-10-235-10-82.ec2.internal.warc.gz"} |
http://proceedings.mlr.press/v38/gunasekar15.html | Consistent Collective Matrix Completion under Joint Low Rank Structure
Suriya Gunasekar, Makoto Yamada, Dawei Yin, Yi Chang
Proceedings of the Eighteenth International Conference on Artificial Intelligence and Statistics, PMLR 38:306-314, 2015.
Abstract
We address the collective matrix completion problem of jointly recovering a collection of matrices with shared structure from partial (and potentially noisy) observations. To ensure well–posedness of the problem, we impose a joint low rank structure, wherein each component matrix is low rank and the latent space of the low rank factors corresponding to each entity is shared across the entire collection. We first develop a rigorous algebra for representing and manipulating collective–matrix structure, and identify sufficient conditions for consistent estimation of collective matrices. We then propose a tractable convex estimator for solving the collective matrix completion problem, and provide the first non–trivial theoretical guarantees for consistency of collective matrix completion. We show that under reasonable assumptions stated in Sec. 3.1, with high probability, the proposed estimator exactly recovers the true matrices whenever sample complexity requirements dictated by Theorem 1 are met. The sample complexity requirement derived in the paper are optimum up to logarithmic factors, and significantly improve upon the requirements obtained by trivial extensions of standard matrix completion. Finally, we propose a scalable approximate algorithm to solve the proposed convex program, and corroborate our results through simulated and real life experiments. | {"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": 0.9176180958747864, "perplexity": 467.4301001690333}, "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-2021-39/segments/1631780057882.56/warc/CC-MAIN-20210926144658-20210926174658-00631.warc.gz"} |
https://vinequai.com/steinersurface | Steiner's Surface
1. viz 1
Your browser does not support HTML5 Canvas
Steiner's surface is a local embedding of the projective plane into 3-dimensional space that was useful for the construction of an eversion of the sphere, and is interesting in its own right. Ironically, it was discovered by Werner Boy when he was tasked to prove that such an immersion did not exist.
The surface faithfully embeds local neighborhoods of the projective plane, but it is not a global embedding, as there are self intersections. It is known that one cannot globally embed the projective plane into 3-dimensional space.
In the animation above, the projective plane is indicated in the bottom left, represented as a disk with diametrically opposite points identified with each other. The animation shows the image of a circle of points as the circle grows steadily toward the boundary of the disk. We can see that the map defines a local embedding because the circle of points don't trample on their immediate neighbors as they get mapped to the surface, and the mapped points are constantly moving across the surface as the radius increases.
When the points reach the outer rim, diametrically opposed points map to the same point of the surface, which shows that the map is well-defined on the projective plane.
Steiner's surface has a three-fold rotational symmetry and a single point where it intersects itself three times, which you can readily identify in the demonstration. It is also unorientable.
It appears as a halfway model in our discussion of sphere eversion for $$n=3$$. That is, it appears in the sphere eversion precisely at the moment where the outside of the sphere becomes the inside and vice versa.
The equations for the parametrization of Steiner's surface that I used to generate the visualization above were discovered by Bryant and Kusner and can be found in the Wikipedia article
The surface is quite complex and can be better understood by viewing various cross sections of the model by adjusting the clipping parameters. In doing so we see that at the top there are three spherical caps that each merge into the other two and combine to form a single cup at the bottom. | {"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": 0.8348979353904724, "perplexity": 260.30612097352997}, "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/1674764500076.87/warc/CC-MAIN-20230203221113-20230204011113-00733.warc.gz"} |
https://makondo.ugr.es/event/0/session/92/contribution/292 | The 35th International Symposium on Lattice Field Theory
18-24 June 2017
Palacio de Congresos
Home > Timetable > Session details > Contribution details
Contribution Parallel
Seminarios 6+7
Weak Decays and Matrix Elements
Electromagnetic Corrections to Decay Amplitudes
Speakers
• Prof. Guido MARTINELLI
Content
We report on the status of our programme to develop a framework for the calculation of electromagnetic corrections to weak decay amplitudes. The $O(1\%)$ precision increasingly being reached in isospin-symmetric QCD calculations necessitates the inclusion of isospin-breaking effects, including electromagnetism, if continuing progress in the determination of the fundamental parameters of the Standard Model and the exploration of the limits of its validity is to be maintained. We briefly review the framework and the demonstration that for leptonic decays of pseudoscalar mesons the $O(1/L)$ finite-volume corrections ($L$ is the spacial extent of the box) are universal and have been calculated. We discuss the work-in-progress to extend the framework to semileptonic decays.
Preferred track (if multiple tracks have been selected)
Weak Decays and Matrix Elements | {"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": 0.9223000407218933, "perplexity": 2253.9882321269743}, "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-2020-05/segments/1579250626449.79/warc/CC-MAIN-20200124221147-20200125010147-00175.warc.gz"} |
https://www.gamedev.net/forums/topic/334516-gnu-and-nasm/ | GNU and NASM
This topic is 4830 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.
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Hi, I tried to write a function in assembly and got it to compile in nasm and I want to call on that function from c++. I got the compilations to work... its just the linking that gives me undefined references. Its just a test run before I want to start writing a few assembly stuff and linking them into c++. I've written a simple test.cpp
#include <stdio.h>
#include <stdlib.h>
#include "assem.h"
int main()
{
int i = getFive();
printf("%d\n", i);
system("pause");
return 0;
}
Then I have a assem.h
#ifndef ASSEM_H
#define ASSEM_H
#ifdef __cplusplus
extern "C" {
#endif
int getFive();
#ifdef _cplusplus
}
#endif
#endif
Now I have assem.asm
section .data
section .text
global _getFive
_getFive:
mov eax, 5
ret
Then I've made a makefile but it basically does this: g++ -c test.cpp -o test.o nasm -fwin32 assem.asm -o assem.o g++ test.o assem.o -o test.exe Then I get an undefined reference to getFive() Can anyone help me? Thanks [Edited by - Last Attacker on July 26, 2005 3:27:43 AM]
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#ifdef _cplusplus
should be
#ifdef __cplusplus
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Sorry I wrote the stuff from my memory.
But I remember using a double _ in the cplusplus thing when I coded it at home and it didn't work.
Edit:
Is my global and label name correctly? I really want to know whats wrong because I want to write a few optimized implementations for our 3rd year project at university and I really don't like AT&T for assembly.
Thanks
[Edited by - Last Attacker on July 26, 2005 7:34:35 AM]
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Hello,
Make sure your naming the function exactly as the linker expects it. So for example, it could be requesting _getFive instead of getFive. Maybe even getFive@0, it depends on what the linker expects. I hope this helps,
JVFF
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Propably.
What naming convention does the GNU C++ compiler use?
I'm using the GNU compiler.
I read just about all over the internet that when using the __cplusplus then I just have to add the single _ infront of the function name.
Thanks
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First step is do get the name gcc expects to see:
nm test.o
This should print all the names in your object file, the line containing getFive contains the symbol name gcc expects.
Second step is to check what name nasm produced, so:
nm assem.o
Does it match the other name ? Maybe an underscor too much or too less ?
Third step:
Did you use the correct object file format ? This depends on if you use cygwin, djgpp or mingw. Just try different object formats, one should work if the names match.
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Hello,
It's been a while since I used gcc. I found a file in the internet about it, and I think it expects an underscore before the function. The link:
http://www.delorie.com/djgpp/doc/ug/asm/calling.html
Hope this helps,
JVFF
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Quote:
Original post by nmiThird step:Did you use the correct object file format ? This depends on if you use cygwin, djgpp or mingw. Just try different object formats, one should work if the names match.
I just tried the OP's example on mingw, and it works without problems.
Programs used:
- gcc version 3.4.2 (mingw-special)
- nasm 0.98.38
Commands used:
g++ -c test.cpp -o test.o
nasmw -fwin32 assem.asm -o assem.o
g++ test.o assem.o -o test.exe
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Thanks. After using the nm program I found that the function name was TOTALLY diffrent... well the prefix and suffix was atleast diffrent. Now it finally works.
Thanks, again!
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It was ages ago I tried something like that, but I think you can tell the linker what name to expect:
int getFive() asm("_getFive");
or something like that..
(I know you solved the problem, but this seems like a nicer solution than using nm)
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× | {"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": 0.26004791259765625, "perplexity": 5629.115469300613}, "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/1539583511314.51/warc/CC-MAIN-20181017220358-20181018001858-00527.warc.gz"} |
http://umr-math.univ-mlv.fr/evenements/exposes/seminaire_cool.1414139400 | ## Univalent maps as pseudo-conjugacies between rational map perturbations
Type:
Type:
Site:
Date:
24/10/2014 - 10:30
Salle:
05
Orateur:
Tan Lei
Localisation:
Université d'Angers
Localisation:
France
Résumé:
We will see in examples how univalent maps arise as pseudo-conjugacies in a dynamical perturbation of a rational map, how to control their conformal and spherical distortions and how to use these controls to get ray-landing properties in the parameter space of rational maps. | {"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": 0.8572720885276794, "perplexity": 2263.8676914035423}, "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-2018-22/segments/1526794866276.61/warc/CC-MAIN-20180524112244-20180524132244-00550.warc.gz"} |
http://semantic-portal.net/concept:1666 | # Background Color
//the background color of a page is set like this
body {
background-color: lightblue;
}
Specifies the background color of an element.
With CSS, a color is most often specified by: a valid color name - like "red", a HEX value - like "#ff0000", an RGB value - like "rgb(255,0,0)".
Background Color
## Background Color — Structure map
Clickable & Draggable! | {"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": 0.30038315057754517, "perplexity": 12521.808850960057}, "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/1631780056902.22/warc/CC-MAIN-20210919220343-20210920010343-00085.warc.gz"} |
https://au.mathematicstip.com/6963-26-solving-absolute-value-equations-and-inequalities.html | # 2.6: Solving Absolute Value Equations and Inequalities
Learning Objectives
• Review the definition of absolute value.
• Solve absolute value equations.
• Solve absolute value inequalities.
## Absolute Value Equations
Recall that the absolute value63 of a real number (a), denoted (|a|), is defined as the distance between zero (the origin) and the graph of that real number on the number line. For example, (|−3|=3) and (|3|=3).
In addition, the absolute value of a real number can be defined algebraically as a piecewise function.
Given this definition, (|3| = 3) and (|−3| = − (−3) = 3).Therefore, the equation (|x| = 3) has two solutions for (x), namely ({±3}). In general, given any algebraic expression (X) and any positive number (p):
In other words, the argument of the absolute value64 (X) can be either positive or negative (p). Use this theorem to solve absolute value equations algebraically.
Example (PageIndex{1}):
Solve: (|x+2|=3).
Solution
In this case, the argument of the absolute value is (x+2) and must be equal to (3) or (−3).
Therefore, to solve this absolute value equation, set (x+2) equal to (±3) and solve each linear equation as usual.
The solutions are (−5) and (1).
To visualize these solutions, graph the functions on either side of the equal sign on the same set of coordinate axes. In this case, (f (x) = |x + 2|) is an absolute value function shifted two units horizontally to the left, and (g (x) = 3) is a constant function whose graph is a horizontal line. Determine the (x)-values where (f (x) = g (x)).
From the graph we can see that both functions coincide where (x = −5) and (x = 1). The solutions correspond to the points of intersection.
Example (PageIndex{2}):
Solve: (| 2 x + 3 | = 4).
Solution
Here the argument of the absolute value is (2x+3) and can be equal to (-4) or (4).
Check to see if these solutions satisfy the original equation.
Check (x=-frac{7}{2})Check (x=frac{1}{2})(egin{array} { r } { | 2 x + 3 | = 4 } { left| 2 left( color{Cerulean}{frac { 1 } { 2 }} ight) + 3 ight| = 4 } { | 1 + 3 | = 4 } { | 4 | = 4 } { 4 = 4 } ::color{Cerulean}{✓} end{array})Table (PageIndex{1})
The solutions are (-frac{7}{2}) and (frac{1}{2}).
To apply the theorem, the absolute value must be isolated. The general steps for solving absolute value equations are outlined in the following example.
Example (PageIndex{3}):
Solve: (2 |5x − 1| − 3 = 9).
Solution
Step 1: Isolate the absolute value to obtain the form (|X| = p).
Step 2: Set the argument of the absolute value equal to (±p). Here the argument is (5x − 1) and (p = 6).
Step 3: Solve each of the resulting linear equations.
Step 4: Verify the solutions in the original equation.
Check (x=-1)Check (x=frac{7}{5})Table (PageIndex{2})
The solutions are (-1) and (frac{7}{5})
Exercise (PageIndex{1})
Solve: (2 - 7 | x + 4 | = - 12).
(-6, -2)
Not all absolute value equations will have two solutions.
Example (PageIndex{4}):
Solve: (| 7 x - 6 | + 3 = 3).
Solution
Begin by isolating the absolute value.
Only zero has the absolute value of zero, (|0| = 0). In other words, (|X| = 0) has one solution, namely (X = 0). Therefore, set the argument (7x − 6) equal to zero and then solve for (x).
Geometrically, one solution corresponds to one point of intersection.
The solution is (frac{6}{7}).
Example (PageIndex{5}):
Solve: (|x+7|+5=4).
Solution
Begin by isolating the absolute value.
In this case, we can see that the isolated absolute value is equal to a negative number. Recall that the absolute value will always be positive. Therefore, we conclude that there is no solution. Geometrically, there is no point of intersection.
There is no solution, (Ø).
If given an equation with two absolute values of the form (| a | = | b |), then (b) must be the same as (a) or opposite. For example, if (a=5), then (b = pm 5) and we have:
In general, given algebraic expressions (X) and (Y):
In other words, if two absolute value expressions are equal, then the arguments can be the same or opposite.
Example (PageIndex{6}):
Solve: (| 2 x - 5 | = | x - 4 |).
Solution
Set (2x-5) equal to (pm ( x - 4 )) and then solve each linear equation.
To check, we substitute these values into the original equation.
Check (x=1)Check (x=3)Table (PageIndex{3})
As an exercise, use a graphing utility to graph both (f(x)= |2x-5|) and (g(x)=|x-4|) on the same set of axes. Verify that the graphs intersect where (x) is equal to (1) and (3).
The solutions are (1) and (3).
Exercise (PageIndex{2})
Solve: (| x + 10 | = | 3 x - 2 |).
(-2, 6)
## Absolute Value Inequalities
We begin by examining the solutions to the following inequality:
(| x | leq 3)
The absolute value of a number represents the distance from the origin. Therefore, this equation describes all numbers whose distance from zero is less than or equal to (3). We can graph this solution set by shading all such numbers.
Certainly we can see that there are infinitely many solutions to (|x|≤3) bounded by (−3) and (3). Express this solution set using set notation or interval notation as follows:
In this text, we will choose to express solutions in interval notation. In general, given any algebraic expression (X) and any positive number (p):
This theorem holds true for strict inequalities as well. In other words, we can convert any absolute value inequality involving "less than" into a compound inequality which can be solved as usual.
Example (PageIndex{7}):
Solve and graph the solution set: (|x+2|<3).
Solution
Bound the argument (x+2) by (−3) and (3) and solve.
Here we use open dots to indicate strict inequalities on the graph as follows.
Using interval notation, ((−5,1)).
The solution to (| x + 2 | < 3) can be interpreted graphically if we let (f ( x ) = | x + 2 |) and (g(x)=3) and then determine where (f ( x ) < g ( x )) by graphing both (f) and (g) on the same set of axes.
The solution consists of all (x)-values where the graph of (f) is below the graph of (g). In this case, we can see that (|x + 2| < 3) where the (x)-values are between (−5) and (1). To apply the theorem, we must first isolate the absolute value.
Example (PageIndex{8}):
Solve: (4 |x + 3| − 7 ≤ 5).
Solution
Begin by isolating the absolute value.
Next, apply the theorem and rewrite the absolute value inequality as a compound inequality.
Solve.
Shade the solutions on a number line and present the answer in interval notation. Here we use closed dots to indicate inclusive inequalities on the graph as follows:
Using interval notation, ([−6,0])
Exercise (PageIndex{3})
Solve and graph the solution set: (3 + | 4 x - 5 | < 8).
Interval notation: ((0, frac{5}{2}))
Next, we examine the solutions to an inequality that involves "greater than," as in the following example:
(| x | geq 3)
This inequality describes all numbers whose distance from the origin is greater than or equal to (3). On a graph, we can shade all such numbers.
There are infinitely many solutions that can be expressed using set notation and interval notation as follows:
In general, given any algebraic expression (X) and any positive number (p):
The theorem holds true for strict inequalities as well. In other words, we can convert any absolute value inequality involving “greater than” into a compound inequality that describes two intervals.
Example (PageIndex{9}):
Solve and graph the solution set: (|x+2|>3).
Solution
The argument (x+2) must be less than (−3) or greater than (3).
Using interval notation, ((−∞,−5)∪(1,∞)).
The solution to (|x + 2| > 3) can be interpreted graphically if we let (f (x) = |x + 2|) and (g (x) = 3) and then determine where (f(x) > g (x)) by graphing both (f) and (g) on the same set of axes.
The solution consists of all (x)-values where the graph of (f) is above the graph of (g). In this case, we can see that (|x + 2| > 3) where the (x)-values are less than (−5) or are greater than (1). To apply the theorem we must first isolate the absolute value.
Example (PageIndex{10}):
Solve: (3 + 2 |4x − 7| ≥ 13).
Solution
Begin by isolating the absolute value.
Next, apply the theorem and rewrite the absolute value inequality as a compound inequality.
Solve.
Shade the solutions on a number line and present the answer using interval notation.
Using interval notation, ((−∞,12]∪[3,∞))
Exercise (PageIndex{4})
Solve and graph: (3 | 6 x + 5 | - 2 > 13).
Using interval notation, (left( - infty , - frac { 5 } { 3 } ight) cup ( 0 , infty ))
Up to this point, the solution sets of linear absolute value inequalities have consisted of a single bounded interval or two unbounded intervals. This is not always the case.
Example (PageIndex{11}):
Solve and graph: (|2x−1|+5>2).
Solution
Begin by isolating the absolute value.
2 } { | 2 x - 1 | > - 3 } end{array})
Notice that we have an absolute value greater than a negative number. For any real number x the absolute value of the argument will always be positive. Hence, any real number will solve this inequality.
Geometrically, we can see that (f(x)=|2x−1|+5) is always greater than (g(x)=2).
All real numbers, (ℝ).
Example (PageIndex{12}):
Solve and graph: (|x+1|+4≤3).
Solution
Begin by isolating the absolute value.
In this case, we can see that the isolated absolute value is to be less than or equal to a negative number. Again, the absolute value will always be positive; hence, we can conclude that there is no solution.
Geometrically, we can see that (f(x)=|x+1|+4) is never less than (g(x)=3).
In summary, there are three cases for absolute value equations and inequalities. The relations (=, <, leq, > ) and (≥) determine which theorem to apply.
## Key Takeaways
• To solve an absolute value equation, such as (|X| = p), replace it with the two equations (X = −p) and (X = p) and then solve each as usual. Absolute value equations can have up to two solutions.
• To solve an absolute value inequality involving “less than,” such as (|X| ≤ p), replace it with the compound inequality (−p ≤ X ≤ p) and then solve as usual.
• To solve an absolute value inequality involving “greater than,” such as (|X| ≥ p), replace it with the compound inequality (X ≤ −p) or (X ≥ p) and then solve as usual.
• Remember to isolate the absolute value before applying these theorems.
Exercise (PageIndex{5})
1. (|x| = 9)
2. (|x| = 1)
3. (|x − 7| = 3)
4. (|x − 2| = 5)
5. (|x + 12| = 0)
6. (|x + 8| = 0)
7. (|x + 6| = −1)
8. (|x − 2| = −5)
9. (|2y − 1| = 13)
10. (|3y − 5| = 16)
11. (|−5t + 1| = 6)
12. (|−6t + 2| = 8)
13. (left| frac { 1 } { 2 } x - frac { 2 } { 3 } ight| = frac { 1 } { 6 })
14. (left| frac { 2 } { 3 } x + frac { 1 } { 4 } ight| = frac { 5 } { 12 })
15. (|0.2x + 1.6| = 3.6)
16. (|0.3x − 1.2| = 2.7)
17. (| 5 (y − 4) + 5| = 15)
18. (| 2 (y − 1) − 3y| = 4)
19. (|5x − 7| + 3 = 10)
20. (|3x − 8| − 2 = 6)
21. (9 + |7x + 1| = 9)
22. (4 − |2x − 3| = 4)
23. (3 |x − 8| + 4 = 25)
24. (2 |x + 6| − 3 = 17)
25. (9 + 5 |x − 1| = 4)
26. (11 + 6 |x − 4| = 5)
27. (8 − 2 |x + 1| = 4)
28. (12 − 5 |x − 2| = 2)
29. (frac{1}{2} |x − 5| − frac{2}{3} = −frac{1}{6})
30. (frac { 1 } { 3 } left| x + frac { 1 } { 2 } ight| + 1 = frac { 3 } { 2 })
31. (−2 |7x + 1| − 4 = 2)
32. (−3 |5x − 3| + 2 = 5)
33. (1.2 |t − 2.8| − 4.8 = 1.2)
34. (3.6 | t + 1.8| − 2.6 = 8.2)
35. (frac{1}{2} |2 (3x − 1) − 3| + 1 = 4)
36. (frac{2}{3} |4 (3x + 1) − 1| − 5 = 3)
37. (|5x − 7| = |4x − 2|)
38. (|8x − 3| = |7x − 12|)
39. (|5y + 8| = |2y + 3|)
40. (|7y + 2| = |5y − 2|)
41. (|5 (x − 2)| = |3x|)
42. (|3 (x + 1)| = |7x|)
43. (left| frac { 2 } { 3 } x + frac { 1 } { 2 } ight| = left| frac { 3 } { 2 } x - frac { 1 } { 3 } ight|)
44. (left| frac { 3 } { 5 } x - frac { 5 } { 2 } ight| = left| frac { 1 } { 2 } x + frac { 2 } { 5 } ight|)
45. (|1.5t − 3.5| = |2.5t + 0.5|)
46. (|3.2t − 1.4| = |1.8t + 2.8|)
47. (|5 − 3 (2x + 1)| = |5x + 2|)
48. (|3 − 2 (3x − 2)| = |4x − 1|)
1. (−9, 9)
3. (4, 10)
5. (−12)
7. (Ø)
9. (−6, 7)
11. (−1, frac{7}{5})
13. (1, frac{5}{3})
15. (−26, 10)
17. (0, 6)
19. (0, frac{14}{5})
21. (−frac{1}{7})
23. (1, 15)
25. (Ø)
27. (−3, 1)
29. (4, 6)
31. (Ø)
33. (−2.2, 7.8)
35. (−frac{1}{6}, frac{11}{6})
37. (1, 5)
39. (−frac{5}{3}, −frac{11}{7})
41. (frac{5}{4} , 5)
43. (−frac{1}{13} , 1)
45. (−4, 0.75)
47. (0, 4)
Exercise (PageIndex{6})
Solve and graph the solution set. In addition, give the solution set in interval notation.
1. Solve for (x: p |ax + b| − q = 0)
2. Solve for (x: |ax + b| = |p + q|)
1. (x = frac { - b q pm q } { a p })
Exercise (PageIndex{7})
Solve and graph the solution set. In addition, give the solution set in interval notation.
1. (|x| < 5)
2. (|x| ≤ 2)
3. (|x + 3| ≤ 1)
4. (|x − 7| < 8)
5. (|x − 5| < 0)
6. (|x + 8| < −7)
7. (|2x − 3| ≤ 5)
8. (|3x − 9| < 27)
9. (|5x − 3| ≤ 0)
10. (|10x + 5| < 25)
11. (left| frac { 1 } { 3 } x - frac { 2 } { 3 } ight| leq 1)
12. (left| frac { 1 } { 12 } x - frac { 1 } { 2 } ight| leq frac { 3 } { 2 })
13. (|x| ≥ 5)
14. (|x| > 1)
15. (|x + 2| > 8)
16. (|x − 7| ≥ 11)
17. (|x + 5| ≥ 0)
18. (|x − 12| > −4)
19. (|2x − 5| ≥ 9)
20. (|2x + 3| ≥ 15)
21. (|4x − 3| > 9)
22. (|3x − 7| ≥ 2)
23. (left| frac { 1 } { 7 } x - frac { 3 } { 14 } ight| > frac { 1 } { 2 })
24. (left| frac { 1 } { 2 } x + frac { 5 } { 4 } ight| > frac { 3 } { 4 })
1. (( - 5,5 ));
3. ([ - 4 , - 2 ]);
5. (emptyset);
7. ([ - 1,4 ]);
9. (left{ frac { 3 } { 5 } ight});
11. ([ - 1,5 ]);
13. (( - infty , - 5 ] cup [ 5 , infty ));
15. (( - infty , - 10 ) cup ( 6 , infty ));
17. (mathbb { R });
19. (( - infty , - 2 ] cup [ 7 , infty ));
21. (left( - infty , - frac { 3 } { 2 } ight) cup ( 3 , infty ));
23. (( - infty , - 2 ) cup ( 5 , infty ));
Exercise (PageIndex{8})
Solve and graph the solution set.
1. (|3 (2x − 1)| > 15)
2. (|3 (x − 3)| ≤ 21)
3. (−5 |x − 4| > −15)
4. (−3 |x + 8| ≤ −18)
5. (6 − 3 |x − 4| < 3)
6. (5 − 2 |x + 4| ≤ −7)
7. (6 − |2x + 5| < −5)
8. (25 − |3x − 7| ≥ 18)
9. (|2x + 25| − 4 ≥ 9)
10. (|3 (x − 3)| − 8 < −2)
11. (2 |9x + 5| + 8 > 6)
12. (3 |4x − 9| + 4 < −1)
13. (5 |4 − 3x| − 10 ≤ 0)
14. (6 |1 − 4x| − 24 ≥ 0)
15. (3 − 2 |x + 7| > −7)
16. (9 − 7 |x − 4| < −12)
17. (|5 (x − 4) + 5| > 15)
18. (|3 (x − 9) + 6| ≤ 3)
19. (left| frac { 1 } { 3 } ( x + 2 ) - frac { 7 } { 6 } ight| - frac { 2 } { 3 } leq - frac { 1 } { 6 })
20. (left| frac { 1 } { 10 } ( x + 3 ) - frac { 1 } { 2 } ight| + frac { 3 } { 20 } > frac { 1 } { 4 })
21. (12 + 4 |2x − 1| ≤ 12)
22. (3 − 6 |3x − 2| ≥ 3)
23. (frac{1}{2} |2x − 1| + 3 < 4)
24. 2 |frac{1}{2} x + frac{2}{3} | − 3 ≤ −1)
25. (7 − |−4 + 2 (3 − 4x)| > 5)
26. (9 − |6 + 3 (2x − 1)| ≥ 8)
27. (frac { 3 } { 2 } - left| 2 - frac { 1 } { 3 } x ight| < frac { 1 } { 2 })
28. (frac { 5 } { 4 } - left| frac { 1 } { 2 } - frac { 1 } { 4 } x ight| < frac { 3 } { 8 })
1. (( - infty , - 2 ) cup ( 3 , infty ));
3. (( 1,7 ));
5. (( - infty , 3 ) cup ( 5 , infty ));
7. (( - infty , - 8 ) cup ( 3 , infty ));
9. (( - infty , - 19 ] cup [ - 6 , infty ));
11. (mathbb { R });
13. (left[ frac { 2 } { 3 } , 2 ight]);
15. (( - 12 , - 2 ));
17. (( - infty , 0 ) cup ( 6 , infty ));
19. ([ 0,3 ]);
21. (frac { 1 } { 2 });
23. (left( - frac { 1 } { 2 } , frac { 3 } { 2 } ight));
25. (left( 0 , frac { 1 } { 2 } ight));
27. (( - infty , 3 ) cup ( 9 , infty ));
Exercise (PageIndex{9})
Assume all variables in the denominator are nonzero.
1. Solve for (x) where (a, p > 0: p |ax + b| − q ≤ 0)
2. Solve for (x) where (a, p > 0: p |ax + b| − q ≥ 0)
1. (frac { - q - b p } { a p } leq x leq frac { q - b p } { a p })
Exercise (PageIndex{10})
Given the graph of (f) and (g), determine the (x)-values where:
(a) (f ( x ) = g ( x ))
(b) (f ( x ) > g ( x ))
(c) (f ( x ) < g ( x ))
1.
2.
3.
4.
1. (a) (−6, 0); (b) ((−∞, −6) ∪ (0, ∞)); (c) ((−6, 0))
3. (a) (Ø); (b) (ℝ); (c) (Ø)
Exercise (PageIndex{11})
1. Make three note cards, one for each of the three cases described in this section. On one side write the theorem, and on the other write a complete solution to a representative example. Share your strategy for identifying and solving absolute value equations and inequalities on the discussion board.
2. Make your own examples of absolute value equations and inequalities that have no solution, at least one for each case described in this section. Illustrate your examples with a graph. | {"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": 0.9613426923751831, "perplexity": 2276.6057950878535}, "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/1637964363510.40/warc/CC-MAIN-20211208114112-20211208144112-00040.warc.gz"} |
https://conwaylife.com/forums/viewtopic.php?p=20779 | 2x2
For discussion of other cellular automata.
Kiran
Posts: 285
Joined: March 4th, 2015, 6:48 pm
Re: 2x2
And here is an MMS breeder which utilises that reaction:
Finally a breeder!
I would add it to the wiki immediately.
Kiran Linsuain
A for awesome
Posts: 2036
Joined: September 13th, 2014, 5:36 pm
Location: 0x-1
Contact:
Re: 2x2
wildmyron wrote:A third(?) crawler eater - using the p26:
Code: Select all
code
Two p4 eaters:
Code: Select all
x = 7, y = 8, rule = B36/S125
bo$2bobo2$3o$5b2o$4bobo$3b2o$3bo!
Code: Select all
x = 11, y = 8, rule = B36/S125
5bo$6bobo2$4b3o$2o7b2o$o2bo4bobo$2b2o3b2o$7bo!
A stable eater might be possible if a catalyst is found that can take the place of the p4 in the second eater.
x₁=ηx
V ⃰_η=c²√(Λη)
K=(Λu²)/2
Pₐ=1−1/(∫^∞_t₀(p(t)ˡ⁽ᵗ⁾)dt)
$$x_1=\eta x$$
$$V^*_\eta=c^2\sqrt{\Lambda\eta}$$
$$K=\frac{\Lambda u^2}2$$
$$P_a=1-\frac1{\int^\infty_{t_0}p(t)^{l(t)}dt}$$
http://conwaylife.com/wiki/A_for_all
Aidan F. Pierce
wildmyron
Posts: 1397
Joined: August 9th, 2013, 12:45 am
Re: 2x2
A for awesome wrote:Two p4 eaters:
Code: Select all
x = 7, y = 8, rule = B36/S125
bo$2bobo2$3o$5b2o$4bobo$3b2o$3bo!
Code: Select all
x = 11, y = 8, rule = B36/S125
5bo$6bobo2$4b3o$2o7b2o$o2bo4bobo$2b2o3b2o$7bo!
A stable eater might be possible if a catalyst is found that can take the place of the p4 in the second eater.
The second pattern doesn't work when the crawler is pulled back - it interacts with the carrier prior to reaching the p4.
The latest version of the 5S Project contains over 226,000 spaceships. There is also a GitHub mirror of the collection. Tabulated pages up to period 160 (out of date) are available on the LifeWiki.
Yimmy
Posts: 10
Joined: February 18th, 2015, 2:01 pm
Re: 2x2
I've been interested in this rule for a while and was wondering what ways I could assist in the research of this rule.
Lewis
Posts: 325
Joined: March 17th, 2009, 5:26 pm
Location: UK
Contact:
Re: 2x2
Yimmy wrote:I've been interested in this rule for a while and was wondering what ways I could assist in the research of this rule.
APGsearch is probably your best bet, especially with some kind of symmetry setting. Although I suppose it depends on what sorts of things you're looking for. The C1 symmetry setting is just starting to uncover unusual oscillators (periods 8, 11, 17), so if someone ran, say D4_+2 long enough it'd probably turn up some interesting oscillators too. And maybe a spaceship/infinite growth mechanism; I'm not sure how thoroughly this rule has been searched for small-ish ships.
For more complex engineered objects, we'd probably need to find a gun first - the minimum period for a c/8 crawler gun in this rule is 34 and so far no oscillators (excluding 2*n boxes and interactions between two lower-period oscillators) have periods greater than 28. So if someone found something like one of the shuttles in Life, that could be potentially useful.
Also, I don't think anyone has found a stable eater for the c/8 crawler yet. Or any crawler reflectors. I don't know how much help apgsearch would be for these though; maybe you'd need a modified version of the dr drifter search program or something.
In fact, even just running a few searches for low-ish period oscillators in WLS or RandomAgar would probably yield results. Most of the things I found (the P7, p12, 24 and 28 and the two p5's that aren't based on the small natural one here posted much earlier in this thread) were found when I was like 16 and too impatient to let searches run to completion. So there's probably a bunch of fairly simple stuff out there that no-one's stumbled across yet. I don't think this rule gets as much attention as HighLife or Move or Seeds etc.
velcrorex
Posts: 339
Joined: November 1st, 2009, 1:33 pm
Re: 2x2
c/3 diagonal puffer. I think this is new?
Code: Select all
x = 32, y = 32, rule = B36/S125
6b4o$4bob2o2bo$3b2o2bobobo$2bobo3bo$b3o6bo$10b3o$2o8b2o$3o5bo4bo$o2bo
3bo5bo$obo9bob4o$bo2b3o4b3ob3o$2bo2b2o3b2o4bo3bo$5bo3b2o5bob2o$7b2obo$
9bo7bo$9b2o7bob3o$9b4o6b2o3bo$9b2o3bo5b3o2bo$12bo2bo4b2o4bo$12bo3bo4bo bo2bo$11bo3b4o2b3o$15bob4obo2bobo$15bobo2b3o5b2o$19b2o5b2ob2o$16bo9bo
3bo$17bo3bo4bobo$18b2o3b3ob3o$21bobo2bo4bo$22bo2b2o3bo$22b2o2bo$23b2o
3bo$27bo! EDIT: And a different one based on the first. Code: Select all x = 44, y = 44, rule = B36/S125 6b4o$4bob2o2bo$3b2o2bobobo$2bobo3bo$b3o6bo$10b3o$2o8b2o$3o5bo4bo$o2bo 3bo5bo$obo9bob4o$bo2b3o4b3ob3o$2bo2b2o3b2o4bo3bo$5bo3b2o5bob2o$7b2obo$9bo7bo$9b2o7bob3o$9b4o6b2o3bo$9b2o3bo5b3o2bo$12bo2bo4b2o4bo$12bo3bo4bo
bo2bo$11bo3b4o2b3o3b2o$15bob4obo2bo3bo$15bobo2b3o3bo2bo$19b2o6bo$16bo 10bo$17bo3bo4bo$18b2o2bo2bo4bo$20bo2b2o4bo$20bo11bo$21b2o4bo4bo$26bo$
33b2o$28b2o4bo$31bo3bo$31b2o2bo$33b2o$37bo$36bo$38bo$39bo2$41bo$42bo$43bo! -Josh Ball. velcrorex Posts: 339 Joined: November 1st, 2009, 1:33 pm Re: 2x2 Smaller c/4. Code: Select all x = 17, y = 6, rule = B36/S125 2bo11bo$o2bo9bo2bo$2o6bo6b2o$7b3o$2bo2bob3obo2bo$3b2o7b2o!
And a 2c/5 with odd symmetry.
Code: Select all
x = 21, y = 61, rule = B36/S125
9b3o$7b7o$5bob2o3b2obo$5b3o5b3o$5bo2bo3bo2bo$3b5ob3ob5o$2b5o2bo
bo2b5o$2bobo4b3o4bobo$3b2obo2bobo2bob2o$3b3o4bo4b3o$b2o2bob7obo2b
2o$6bo3bo3bo$b2o6b3o6b2o$8bo3bo$b2o3bo3bo3bo3b2o$7bobobobo$b2o15b
2o$3bo4bo3bo4bo$2b6o5b6o$7bo5bo$3bobobo2bo2bobobo$7b2obob2o$2bob
obo2b3o2bobobo$4bobo2bobo2bobo$4bo11bo$3bo4bo3bo4bo$4b2o2bo3bo2b
2o$5b3o5b3o$3bo4bo3bo4bo$3b4o2bobo2b4o$2b3ob2o5b2ob3o$b6o7b6o$3b
o13bo$3bo13bo$o3bo2bo5bo2bo3bo$bob3o2bo3bo2b3obo$2o2bo3bo3bo3bo2b
2o$bob4o7b4obo$2bo5bo3bo5bo$2bo15bo2$2bo2bo9bo2bo$3bo2bobo3bobo2b o$7bo5bo$3bob2o7b2obo$4bo4bobo4bo$6b3o3b3o$3b3obo5bob3o$2b2obo9b ob2o$5b3o5b3o$2b3obobo3bobob3o$2bo2bo9bo2bo$2bo2bo3bobo3bo2bo$3b
o13bo$2b3obo3bo3bob3o$3b4o3bo3b4o$5b3o5b3o$5bob2o3b2obo$2b2o3bo5b o3b2o$2bo3bo7bo3bo$3b3o9b3o! -Josh Ball. Saka Posts: 3399 Joined: June 19th, 2015, 8:50 pm Location: In the kingdom of Sultan Hamengkubuwono X Contact: Re: 2x2 Double pipsquirter? (not sure) see gen 12 Code: Select all x = 4, y = 15, rule = B36/S125 4o$4o$4o$4o$4o$4o$4o$4o$4o$4o$4o$4o$4o$4o$4o! Code: Select all o3b2ob2obo3b2o2b2o$bo3b2obob3o3bo2bo$2bo2b3o5b3ob4o$3o3bo2bo2b3o3b3o$4bo4bobo4bo$2o2b2o2b4obo2bo3bo$2ob4o3bo2bo2bo2bo$b2o3bobob2o$3bobobo5b obobobo$3bobobob2o3bo2bobo!
(Check gen 3)
wildmyron
Posts: 1397
Joined: August 9th, 2013, 12:45 am
Re: 2x2
A few interesting results from RandAgar:
Two high period wicks - p34 and p58:
Code: Select all
#CXRLE Pos=-34,-25
x = 68, y = 49, rule = B36/S125:T70,70
3bo4bo8bo4bo8bo4bo8bo4bo8bo4bo$4bo2bo10bo2bo10bo2bo10bo2bo10bo2bo2$bo
8bo4bo8bo4bo8bo4bo8bo4bo8bo$2b2o4b2o6b2o4b2o6b2o4b2o6b2o4b2o6b2o4b2o$b
2o6b2o4b2o6b2o4b2o6b2o4b2o6b2o4b2o6b2o$3bo4bo8bo4bo8bo4bo8bo4bo8bo4bo 2$o10bo2bo10bo2bo10bo2bo10bo2bo10bo$bo8bo4bo8bo4bo8bo4bo8bo4bo8bo23$bo
bo4bobo4bobo4bobo4bobo4bobo4bobo4bobo4bobo4bobo$2bo6bo6bo6bo6bo6bo6bo 6bo6bo6bo$bobo4bobo4bobo4bobo4bobo4bobo4bobo4bobo4bobo4bobo12$bobo4bob o4bobo4bobo4bobo4bobo4bobo4bobo4bobo4bobo$2bo6bo6bo6bo6bo6bo6bo6bo6bo
6bo$bobo4bobo4bobo4bobo4bobo4bobo4bobo4bobo4bobo4bobo! Several diagonal waves - one at c/10 Code: Select all x = 70, y = 70, rule = B36/S125:T70,70 67bobo$66bo2bo$65bo2$65b2o$63bo$64bo$60bobo$59bo2bo$58bo2$58b2o$56bo$
57bo$53bobo$52bo2bo$51bo2$51b2o$49bo$50bo$46bobo$45bo2bo$44bo2$44b2o$42bo$43bo$39bobo$38bo2bo$37bo2$37b2o$35bo$36bo$32bobo$31bo2bo$30bo2$
30b2o$28bo$29bo$25bobo$24bo2bo$23bo2$23b2o$21bo$22bo$18bobo$17bo2bo$16bo2$16b2o$14bo$15bo$11bobo$10bo2bo$9bo2$9b2o$7bo$8bo$4bobo$3bo2bo$2b o2$2b2o$o$bo!
and two at c/24
Code: Select all
x = 69, y = 69, rule = B36/S125:T70,70
33bo33bo$33bo31b2o$31b3o30bo3bo$30bo33bo3bo$30bo32bo4bo$28b3o34b3o2$
26bo33bo$26bo31b2o$24b3o30bo3bo$23bo33bo3bo$23bo32bo4bo$21b3o34b3o2$
19bo33bo$19bo31b2o$17b3o30bo3bo$16bo33bo3bo$16bo32bo4bo$14b3o34b3o2$
12bo33bo$12bo31b2o$10b3o30bo3bo$9bo33bo3bo$9bo32bo4bo$7b3o34b3o2$5bo
33bo$5bo31b2o$3b3o30bo3bo$2bo33bo3bo$2bo32bo4bo$3o34b3o2$32bo35bo$30b 2o36bo$29bo3bo32b3o$29bo3bo31bo$28bo4bo31bo$30b3o30b3o2$25bo35bo$23b2o 36bo$22bo3bo32b3o$22bo3bo31bo$21bo4bo31bo$23b3o30b3o2$18bo35bo$16b2o 36bo$15bo3bo32b3o$15bo3bo31bo$14bo4bo31bo$16b3o30b3o2$11bo35bo$9b2o36b o$8bo3bo32b3o$8bo3bo31bo$7bo4bo31bo$9b3o30b3o2$4bo35bo$2b2o36bo$bo3bo
32b3o$bo3bo31bo$o4bo31bo$2b3o30b3o! The c/10 wave looks promising and I believe is within the realm of finding supports with current search tools, however I haven't had any success with JLS so far. The latest version of the 5S Project contains over 226,000 spaceships. There is also a GitHub mirror of the collection. Tabulated pages up to period 160 (out of date) are available on the LifeWiki. Saka Posts: 3399 Joined: June 19th, 2015, 8:50 pm Location: In the kingdom of Sultan Hamengkubuwono X Contact: Re: 2x2 A few objects that are not on the database but may have been found: c/3 Code: Select all x = 13, y = 13, rule = B36/S125 8b2o$4b2ob2o3bo$3b7o$2bo2bobob2obo$5b2obo$b2o$2o$b2o$5b2obo$2bo2bobob
2obo$3b7o$4b2ob2o3bo$8b2o! Code: Select all x = 28, y = 9, rule = B36/S125 8bobo13bo$7bo16b2o$b3ob3o13b6o$6bo2b2o8bo2bobo2bo$5ob5o8bob2o2b2o$5ob
2o9bobob2o$5b2o2b3obo2bob3o$b3o5bo2bo2b6o$10bo3b2o2bo! p10 with undimensional predecesor: Code: Select all x = 7, y = 1, rule = B36/S125 7o! Code: Select all o3b2ob2obo3b2o2b2o$bo3b2obob3o3bo2bo$2bo2b3o5b3ob4o$3o3bo2bo2b3o3b3o$4bo4bobo4bo$2o2b2o2b4obo2bo3bo$2ob4o3bo2bo2bo2bo$b2o3bobob2o$3bobobo5b obobobo$3bobobob2o3bo2bobo!
(Check gen 3)
Lewis
Posts: 325
Joined: March 17th, 2009, 5:26 pm
Location: UK
Contact:
Re: 2x2
Saka wrote: p10 with undimensional predecesor:
Code: Select all
x = 7, y = 1, rule = B36/S125
7o!
A 5x1 line produces the same object:
Code: Select all
x = 5, y = 1, rule = B36/S125
5o!
danieldb
Posts: 163
Joined: July 15th, 2015, 4:27 pm
Location: Right behind you holding a knife
Contact:
Re: 2x2
Sorry if I am late, but an oscillator of p10 I'm calling "paired M's" (because there's a p2 that I've named "M" because that's what it looks like) can eat a glider:
Code: Select all
x = 14, y = 7, rule = B36/S125
10bo$10bo2bo$b2ob2o4bobo$o5bo$2obob2o5bo$o5bo$b2ob2o!
moved to drc
wildmyron
Posts: 1397
Joined: August 9th, 2013, 12:45 am
Re: 2x2
Some new oscillators found with JLS: an extensible p4, a p5, a p6 and a p8. I'm surprised the p6 is new - at least I wasn't able to find it in this thread.
Code: Select all
x = 105, y = 102, rule = B36/S125
o4bo6bobobobobo2bobobo5bobobo2bobobo2bobobo2bobobo2bobobobobo2bobobo2b
obobo2bobobo2bobobo2bobobo$o4bo6bobobobobo2bobobo5bobobo2bobobo2bobobo 2bobobo2bobobobobo2bobobo2bobobo2bobobo2bobobo2bobobo$14bo3bo6bo9bo6bo
6bo6bo6bo3bo6bo6bo6bo6bo6bo$2b2o9bo2bobo4bobobo6bo2bo2bobobo4bobo3bo2b o3bo2bobo4bobobo2bo2bo3bo2bo3bobo4bobobo$12b2o3b2o2b3obo7b2o3bo3bob3o
2b2o4bob2o2b2o3b2o2b3obo3bo3b2o2b2obo4b2o2b3obo$5bo6b2o3b2o2b3obo7b2o 3bo3bob3o2b2o4bob2o2b2o3b2o2b3obo3bo3b2o2b2obo4b2o2b3obo$5bo7bo2bobo4b
obobo6bo2bo2bobobo4bobo3bo2bo3bo2bobo4bobobo2bo2bo3bo2bo3bobo4bobobo$14bo3bo6bo9bo6bo6bo6bo6bo3bo6bo6bo6bo6bo6bo$5bo6bobobobobo2bobobo5bobo
bo2bobobo2bobobo2bobobo2bobobobobo2bobobo2bobobo2bobobo2bobobo2bobobo$5bo6bobobobobo2bobobo5bobobo2bobobo2bobobo2bobobo2bobobobobo2bobobo2bo bobo2bobobo2bobobo2bobobo12$25b2o3b2o$26b2ob2o$24bobobobobo$24bo7bo$
28bo$26bo3bo2$25bob3obo$28bo$2b2o21bo2bo2bo$16b2o21b2o$o13bo6bobo3b3o
3bobo6bo$o13b3o2bo6b5o6bo2b3o$15bo5bo3b3ob3o3bo5bo$2b2o12bobo2b3ob2o3b 2ob3o2bobo$15bo5bo3b3ob3o3bo5bo$5bo8b3o2bo6b5o6bo2b3o$5bo8bo6bobo3b3o
3bobo6bo$16b2o21b2o$2b2o21bo2bo2bo$28bo$25bob3obo2$26bo3bo$28bo$24bo7b o$24bobobobobo$26b2ob2o$25b2o3b2o11$2b2o$15b2o$o14bo2bo$o12bo2bo$12bo 4bo$2b2o8bo4bo$13bo2bo$o4bo9bo2bo$o4bo9b2o2$2b2o19$19bo$2b2o12bobo$20b o$o4bo10bo$o4bo8bo2bobobobo$12bo3bo3bo$2b2o9bo9bo$16bo3bo3bo$o4bo7bobo bobo2bo$o4bo14bo$16bo$2b2o14bobo$17bo! The latest version of the 5S Project contains over 226,000 spaceships. There is also a GitHub mirror of the collection. Tabulated pages up to period 160 (out of date) are available on the LifeWiki. Lewis Posts: 325 Joined: March 17th, 2009, 5:26 pm Location: UK Contact: Re: 2x2 The p6 (and it's smaller variant) both occur naturally; I (possibly re-)discovered them back in 2011, but they could have been known before that. I've got the p8 saved as well, but no idea who found it and when. The P4 and P5 are definitely new though. I've stuck an updated collection in the first post. I've got a big annotated text file saying who found what, and I could upload that somewhere too if anyone wants. wildmyron Posts: 1397 Joined: August 9th, 2013, 12:45 am Re: 2x2 Lewis wrote:The p6 (and it's smaller variant) both occur naturally; I (possibly re-)discovered them back in 2011, but they could have been known before that. I've got the p8 saved as well, but no idea who found it and when. The P4 and P5 are definitely new though. Thanks for checking. I had noticed the narrower p6, but neglected to check catagolue for the wider one. I've even contributed a fair fraction of the symmetrical soups it's been found in! Speaking of which, I took up your idea of running apgsearch with D4_+2 symmetry in the hope of finding oscillators of new periods, but it's not looking very promising so far after 100 million soups. I'm also running dr in the hope of finding new oscillators, but again not very promising. Not sure if I'm on the right track with either of those efforts. Lewis wrote:I've stuck an updated collection in the first post. Fantastic! Thanks for the update. The latest version of the 5S Project contains over 226,000 spaceships. There is also a GitHub mirror of the collection. Tabulated pages up to period 160 (out of date) are available on the LifeWiki. Lewis Posts: 325 Joined: March 17th, 2009, 5:26 pm Location: UK Contact: Re: 2x2 Two variations of a new (?) P6: Code: Select all x = 32, y = 15, rule = B36/S125 4b2obo18b2o$8bo13b2obo$3bo5bo17bo2bo$2bo5bobo10bo4bo2bo$bob2o3bo3bo7bo 10bo$o11bo6bob2o6b2o$18bo$o11bo$o3bo3b2obo6bo$2bobo5bo6bo2bo$3bo5bo7bo bo$4bo$5bob2o11bobo$19bo2bo$21bo! velcrorex Posts: 339 Joined: November 1st, 2009, 1:33 pm Re: 2x2 Useless wide c/2. Code: Select all x = 117, y = 15, rule = B36/S125 91b3o7bo$15bo7b3o37b3o21b3ob3ob3obobobo$13bobobob3ob3ob3o21b3o5b3ob3ob 3o13b3ob3obo3b3o6bo$12bo6b3o3bob3ob3o13b3ob3ob3ob3obobob3ob3o5b3ob3obo
7bobo3bobboo$11boobbo3bobo7bob3ob3o5b3ob3obo3b3obo4bo4bob3ob3ob3obo9bo 4bob4oboo$10boob4obo4bo9bob3ob3ob3obo7bo8bo8bob3obo14boboobbo4boo$10b oo4bobboobo14bob3obo9bo9bobbo9bo13bobobob3o4boo3bo$8bo3boo4b3obobobo
13bo13bobo5boboo8b5o7bobobo5b3oboobobobb4o$5b4obboboboob3o5bobobo7b5o 8boboo6bo5bo5bo3boo3bobobo6bobo6bob3obo$8bob3obo6bobo6bobobo3boo3bo4b
4o4bo4bo3bo14bobo6bo3bo4bo5bobbooboobo$3bobooboobbo5bo4bo3bo6bobo15bo 3b7o10bobo9bo11boo14b4o$4o14boo11bo9bobo4bo10boobboo16bo20boboobo4bo$4bo4boboobo20bo14bobo3bobb4o41boo10bo$o10boo45boo44boo6bobo$bbobo6boo 45boo3bo! Has anyone had any luck searching for other spaceship velocities? Various partials looks promising. EDIT: New p8 oscillator: Code: Select all x = 15, y = 9, rule = B36/S125 2bo4bo4bo$2bo4bo4bo$obobo5bobobo$obobo5bobobo$4bob3obo$obobo2bo2bobobo
$obobo5bobobo$2bo4bo4bo$2bo4bo4bo! -Josh Ball. wildmyron Posts: 1397 Joined: August 9th, 2013, 12:45 am Re: 2x2 velcrorex wrote:Has anyone had any luck searching for other spaceship velocities? Various partials looks promising. I thought I had completed a few gfind searches but can't find anything recorded. So only thing I've seriously investigated is the c/10 diagonal wave posted above. Attached is a c/10 JLS search which I've run to completion with no solution found. Unfortunately I didn't include don't care cells so if there's a longer solution at that width I missed it. I'm currently continuing a similar search for supports of width 11. Is there an up to date summary of known velocities somewhere? Attachments B36S125-c10_dWave_support-NONE.zip c/10 diagonal wave supports - unsuccessful (2.15 KiB) Downloaded 133 times The latest version of the 5S Project contains over 226,000 spaceships. There is also a GitHub mirror of the collection. Tabulated pages up to period 160 (out of date) are available on the LifeWiki. velcrorex Posts: 339 Joined: November 1st, 2009, 1:33 pm Re: 2x2 c/5 orthogonal: Code: Select all x = 15, y = 45, rule = B36/S125 7bo$7bo$7bo$7bo2$4b3ob3o$5bo3bo$5bo3bo$5b5o$3bobo3bobo$5bobobo$7bo$4b
2obob2o$7bo2$5b2ob2o$6bobo$bo11bo$bobobo3bobobo$5bo3bo$3bob2ob2obo$2o
3bo3bo3b2o$o13bo$bob2o5b2obo$2bo2bo3bo2bo$2b5ob5o$5b2ob2o$5b2ob2o$3b2o bobob2o$bo5bo5bo$b2obo5bob2o$3b3o3b3o$4bo2bo2bo$7bo$5bo3bo$3bobo3bobo$2bo2bo3bo2bo$2bobobobobobo$6bobo$4b2o3b2o$bo3bo3bo3bo$5bo3bo$ob2o7b2ob o$b2obo5bob2o$3o9b3o! -Josh Ball. Scorbie Posts: 1445 Joined: December 7th, 2013, 1:05 am Re: 2x2 @Velcrorex Sorry to tell you that Lewis found the exact same one on page 2. How did you find it? with gfind? Best wishes to you, Scorbie Lewis Posts: 325 Joined: March 17th, 2009, 5:26 pm Location: UK Contact: Re: 2x2 P4 oscillator that produces sparks: Code: Select all x = 10, y = 14, rule = B36/S125 2bo3bo$3b2obo$5bo2$bo2bo2bo$o4b2o2bo$ob5o$ob5o$o4b2o2bo$bo2bo2bo2$5bo$3b2obo$2bo3bo!
velcrorex
Posts: 339
Joined: November 1st, 2009, 1:33 pm
Re: 2x2
Scorbie wrote:@Velcrorex Sorry to tell you that Lewis found the exact same one on page 2. How did you find it? with gfind?
Yep. I guess I didn't read through everything well enough.
Still, here's a different c/5. Maybe this one is new.
Code: Select all
x = 14, y = 45, rule = B36/S125
3bo6bo$2b2o6b2o$2b2o6b2o$3b2ob2ob2o$3bo2b2o2bo$3b3o2b3o$4bo4bo$2bobo4bobo$3bo6bo$6b2o$5b4o2$4bo4bo2$5bo2bo$5bo2bo$5b4o$6b2o$b3o
6b3o$4b6o$4b6o$4b2o2b2o$5bo2bo$4bob2obo$4b6o$5b4o2$3b2o4b2o$obo8b obo$3bobo2bobo$3bo6bo$14o$2bob2o2b2obo$2bo2b4o2bo$3bo2b2o2bo2$6b
2o2$4b2o2b2o$3b8o$b3obo2bob3o$o2b2o4b2o2bo$2obobo2bobob2o$o2bobo
2bobo2bo$b2obo4bob2o! -Josh Ball. velcrorex Posts: 339 Joined: November 1st, 2009, 1:33 pm Re: 2x2 gsearch found this possible engine. I have no idea what to do with it, or if it's useful in any way. Here goes: Code: Select all x = 51, y = 8, rule = B36/S125 b2o$o$o2$3b2o6b2o32b2o$bob3o37bob3o$5bo2bo38bo2bo$2b3ob3o35b3ob3o! Take the pattern on the left, and remove the still lives to get the pattern on the right. Then run for 123 generations and you get the pattern on the left moved over 3 and down 2 squares. If the still lifes remain in place the reaction doesn't work. So to create some kind of ship we would need to remove those still lives somehow every time. Also, here's a few osccilators. A p5 (previously known), p10 and their hybrid, as well as a few p8. Code: Select all x = 65, y = 30, rule = B36/S125 47bo12bo$13bo32bo14bo$14b2o28bo2bo2bobo2bobo2bo2bo$14bo2bo25bo5b3o4b3o
5bo$17bo28bo5bo2bo5bo$15b3obo24bo2b4o6b4o2bo$19bo26b2o12b2o$17b2obo$19bob2o$20bo$20bob3o$22bo24bo12b2o$22bo2bo20bo10b4o2bo$24b2o18bo2bo2bo
bo2bo5bo$26bo16bo5b3o4b3o5bo$46bo5bo2bobo2bo2bo$44bo2b4o10bo$46b2o12bo
$ob2o11bob2o$o3bo10bo3bo$2bo14bo$3b3o12b3o$4b3o12bob2o$7bo12bo$5bo3bo 10bob3o29b2o$6b2obo12bo26bo3bo3bo$22bo2bo23b2o2bobo$24b2o22bo3bo2bo$26bo22bo3bo3bo$54b2o!
-Josh Ball.
velcrorex
Posts: 339
Joined: November 1st, 2009, 1:33 pm
Re: 2x2
c/5 diagonal ship:
Code: Select all
x = 40, y = 40, rule = B36/S125
30bo2bo$30bo$32bo$30b2o$26b$28b3o$28bobo8bo$26b2obo7bo$26bo9bo$30bo2b2obob2o$29bo2bobo$25b2obo4b2o$27bo4bo$21b2o2bo2bo2b2o$20bo
2bo2bobo$20b5o$18bo4b3o$16b2obo4bobo$14bo4b2o3bobo$17bo2b2o2b2o$
15b2o4b2o$10b2o2b2o7bo$9b2ob2obo4bobo$10bob3o4bo2bo$17b3o$8bo7bo bo2bo$9bob2o3b2o$9b2o2bo2b2o$9bobobo4bo$7bo4bo3b3o$6b2o3b3o3bo$2b 5o7bo$2b4o3b2o$8b2o$2b3o2b2o$obo2bob2o$bobobob2o$obob2ob2o$3bo\$2b
obo!
-Josh Ball.
Scorbie
Posts: 1445
Joined: December 7th, 2013, 1:05 am
Re: 2x2
Huh, pretty amazing discoveries in such a short period of time! I haven't seen any of them in the forums, but I'm new to this rule. Perhaps wildmyron or Lewis could verify whether it's new?
Best wishes to you, Scorbie | {"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": 0.4738248884677887, "perplexity": 3986.6506619140773}, "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-2020-24/segments/1590347391277.13/warc/CC-MAIN-20200526160400-20200526190400-00585.warc.gz"} |
http://etheses.bham.ac.uk/3268/ | eTheses Repository
# Glial cell line-derived neurotrophic factor effects on dental pulp cells and osteoblast-like cells
Gale, Zoe (2012)
Ph.D. thesis, University of Birmingham.
PDF (7Mb)
## Abstract
Glial cell line-derived neurotrophic factor (GDNF) is a growth factor promoting survival, proliferation and differentiation of neural crest cells. Neural crest cells play an important role within mesenchymal tissues during dental pulp and calvarial bone development. GDNF also has a role within non-neuronal tissues and is expressed during dental development. GDNF null mutations prevent the formation of the mineralised hard tissues of the tooth. The hypothesis for this study was that GDNF affects mesenchymal dental pulp cells (DPC), promoting the regenerative responses of mineralised tissues. This study utilised cell culture models to investigate the direct effects of GDNF on the proliferation and differentiation of dental pulp cells, bone marrow mesenchymal stromal/stem cells (BMSC) and calvarial osteoblasts. This research demonstrated that these culture models expressed GDNF and its receptors GFR$$\alpha$$1 and RET. GDNF was shown to directly stimulate DPC and osteoblast-like cell proliferation and differentiation. Moreover, GDNF was cytoprotective when DPCs were cultured under conditions reflecting aspects of inflammation, which may occur during repair. These conditions included supplementation with the pro-inflammatory cytokine TNF$$\alpha$$ and culture under serum-starved conditions. It is proposed that GDNF may play an important regulatory role in dental pulp homeostasis and bone metabolism.
Type of Work: Ph.D. thesis. Scheven, Ben and Cooper, P R Colleges (2008 onwards) > College of Medical & Dental Sciences School of Dentistry, Department of Oral Biology Published articles related to this research are available at: http://eprints.bham.ac.uk/1141/ http://eprints.bham.ac.uk/1142/ QR MicrobiologyRK Dentistry University of Birmingham 3268
This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder.
Repository Staff Only: item control 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": 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": 0.2298348844051361, "perplexity": 15929.086898269246}, "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/1405997903265.4/warc/CC-MAIN-20140722025823-00199-ip-10-33-131-23.ec2.internal.warc.gz"} |
http://physics.stackexchange.com/questions/49774/why-must-quantum-logic-gates-be-linear-operators?answertab=active | # Why must quantum logic gates be linear operators?
Why must quantum logic gates be linear operators? I mean, is it just a consequence of quantum mechanics postulates?
-
Suppose you pick a state $|\psi_i\rangle$ at random with probability $p_i$ and send it through a logic gate denoted by $G$. This random state is written as a density matrix $\rho = \sum_i p_i |\psi_i\rangle\!\langle\psi_i|$. Denote $G(|\psi_i\rangle\!\langle\psi_i|)$ as the result of applying $G$ to a particular state.
Now if the input is $|\psi_i\rangle\!\langle\psi_i|$ with probability $p_i$, then output is $G(|\psi_i\rangle\!\langle\psi_i|)$ also with probability $p_i$. Thus, the output state must be $\sum_i p_i G(|\psi_i\rangle\!\langle\psi_i|)$ and therefore $$G(\rho) \;=\; G\left(\sum_i p_i |\psi_i\rangle\!\langle\psi_i|\right) \;=\; \sum_i p_i G\Bigl(|\psi_i\rangle\!\langle\psi_i|\Bigr)\,.$$ This can be extended to random mixed input $\rho_i$ in place of $|\psi_i\rangle$, leading us to conclude that $G(\sum_i p_i \rho_i) = \sum_i p_i G(\rho_i)$, which is precisely the definition of linearity. | {"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": 0.9797977209091187, "perplexity": 65.79221442294053}, "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-2015-35/segments/1440645367702.92/warc/CC-MAIN-20150827031607-00203-ip-10-171-96-226.ec2.internal.warc.gz"} |
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1690 questions | {"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": 0.8675217628479004, "perplexity": 5482.090961876326}, "config": {"markdown_headings": false, "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-2022-33/segments/1659882571210.98/warc/CC-MAIN-20220810191850-20220810221850-00077.warc.gz"} |
https://gamedev.stackexchange.com/questions/58191/finding-vectors-with-two-points?noredirect=1 | Finding vectors with two points
We're are trying to get the direction of a projectile but we can't find out how
For example:
[1,1] will go SE
[1,-1] will go NE
[-1,-1] will go NW
and [-1,1] will go SW
we need an equation of some sort that will take the player pos and the mouse pos and find which direction the projectile needs to go.
Here is where we are plugging in the vectors:
def update(self):
self.rect.x += self.vector[0]
self.rect.y += self.vector[1]
Then we are blitting the projectile at the rects coords.
• Is this strictly tile-based? Must the projectile travel at angles or only in strictly axis-aligned directions? Jun 27 '13 at 0:59
• i needs to be able to travel in any direction so if you click in front of the player it will travel forward if you click in back it will travel backwards etc Jun 27 '13 at 1:01
• Possible duplicate: gamedev.stackexchange.com/questions/49290/…
– House
Jun 27 '13 at 1:26
• No, 360 degree mobility not compass directions! Jun 27 '13 at 1:28
• If you take your endpoint minus the starting point you'll get a vector from start to end point. Is this what you're looking for? I'm not sure I understood correctly. Jun 27 '13 at 1:29
To compute a direction you just need subtraction, and ideally normalisation.
self.vector = (mouse.position - player.position).normalize()
Note that your loop update should take the velocity and time between two frames into account:
self.rect.x += speed * timestep * self.vector[0]
self.rect.y += speed * timestep * self.vector[1]
• we got it all to work but thanks for the good answer we may use it to shorten the code :) Jul 27 '13 at 22:08
A vector is a position in space relative to other vectors, and by using Pythagoras and some Trigonometry, we can determine the vectors direction and distance in relation to a target vector.
For the projectile, you are going to need to determine the length of its flight path from the start to the end vector and the angle to which you must launch that projectile.
To find the magnitude(direction): Say we have two vectors in R2(2D Cartesian coordinate system): P(3,4) Q(6,8) we must subtract each of the corresponding X and Y terms, then subtract those two elements, square them, then take the root of the whole equation, this is illustrated as follows:
sqrt((6-3)^2-(8-4)^2) which equates to roughly: 2.6458 (Euler angles)
Now we have the distance between the two vectors, it is time to generate the angle:
Tan((8-4)/(6-8)) Which roughly equates to: 1.285
So now rotate your projectile to 1.285 degrees and then offset the projectile for a distance of 2.6458.
Albeit not a complete solution, you can do this check each time the target moves and update the destination of the projectile, you will however, need to find a suitable method to transition between angles, otherwise the result may look choppy. | {"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": 0.6480848789215088, "perplexity": 825.318697248841}, "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-2021-43/segments/1634323584554.98/warc/CC-MAIN-20211016074500-20211016104500-00573.warc.gz"} |
https://physics.stackexchange.com/questions/594496/does-spin-really-have-no-classical-analogue/594544#594544 | # Does spin really have no classical analogue?
It is often stated that the property of spin is purely quantum mechanical and that there is no classical analog. To my mind, I would assume that this means that the classical $$\hbar\rightarrow 0$$ limit vanishes for any spin-observable.
However, I have been learning about spin coherent states recently (quantum states with minimum uncertainty), which do have a classical limit for the spin. Schematically, you can write down an $$SU(2)$$ coherent state, use it to take the expectation value of some spin-operator $$\mathcal{O}$$ to find
$$\langle \mathcal{\hat{O}}\rangle = s\hbar*\mathcal{O},$$
which has a well defined classical limit provided you take $$s\rightarrow \infty$$ as you take $$\hbar\rightarrow 0$$, keeping $$s\hbar$$ fixed. This has many physical applications, the result usually being some classical angular momentum value. For example, one can consider a black hole as a particle with quantum spin $$s$$ whose classical limit is a Kerr black hole with angular momentum $$s\hbar*\mathcal{O}$$.
Why then do people say that spin has no classical analog?
• The electron has spin $s=1/2$. Like you said the classical limit involves taking $s\rightarrow\infty$, so the electron spin is very far from the classical limit, ie it is quantum. Nov 17 '20 at 15:56
• Sure, but what I mean is that usually, people claim that it can't be analogous to angular momentum because a particle is "point like", yet the large-spin limit is angular momentum. Doesn't it make more sense to assume that particles aren't point like? Nov 17 '20 at 16:01
• Another way to frame this question: if spin has no classical analogue, as many QM books state, why is it that something like the Belinfante tensor for a classical field theory includes a spin contribution term. (This seems to be the crux of Ohanian's article) Nov 17 '20 at 16:19
• This probably helps: physics.stackexchange.com/a/284889/226902 , see also journals.aps.org/pr/abstract/10.1103/PhysRev.121.1833 Nov 17 '20 at 16:21
• Can we stop an electron spinning? A spinning classical body can be stopped by applying a suitable torque. There is no such possibility for quantum particles. Nov 17 '20 at 16:36
You're probably overthinking this. "Spin has no classical analogue" is usually a statement uttered in introductory QM, where we discuss how a quantum state differs from the classical idea of a point particle. In this context, the statement simply means that a classical point particle as usually imagined in Newtonian mechanics has no intrinsic angular momentum - the only component to its total angular momentum is that of its motion, i.e. $$r\times p$$ for $$r$$ its position and $$p$$ its linear momentum. Angular momentum of a "body" in classical physics implies that the body has an extent and a quantifiable motion rotating around its c.o.m., but it does not in quantum mechanics.
Of course there are many situations where you can construct an observable effect of "spin" on the angular momentum of something usually thought of as "classical". These are just demonstrations that spin really is a kind of angular momentum, not that spin can be classical or that the angular momentum you produced should also be called "spin".
Likewise there are classical "objects" that have intrinsic angular momentum not directly connected to the motion of objects, like the electromagnetic field, i.e. it is also not the case that classical physics does not possess the notion of intrinsic angular momentum at all.
"Spin is not classical" really is just supposed to mean "A classical Newtonian point particle possesses no comparable notion of intrinsic angular momentum". (Note that quantization is also not a particular property of spin, since ordinary angular momentum is also quantized, as seen in e.g. the azimuthal quantum number of atomic orbitals)
It's seemingly unappreciated by many people that there are different classical limits of quantum mechanics. At least there are two, a particle limit where you take $$\hbar\to 0$$ and $$ω\to\infty$$ while holding $$\hbar ω$$ and $$n$$ (particle count) fixed, and a wave limit where you take $$\hbar\to 0$$ and $$n\to\infty$$ while holding $$n\hbar$$ and $$ω$$ fixed.
In my experience, phenomena that disappear in the particle limit are often called "purely quantum" even when they survive essentially unchanged in the wave limit. Intrinsic spin is one example; the Aharonov-Bohm effect is another. Maxwell's electrodynamics should be purely quantum by this definition, so I suppose a secondary condition is that the phenomenon has to have been (re)discovered by a physicist after the 1920s, so that the claim isn't so obviously wrong.
The Dirac equation is also often called purely quantum for reasons that are unclear to me – perhaps simply because it contains a factor of $$i\hbar$$ in Dirac's arbitrarily chosen units. It's a classical spin-½ wave equation that just happened to be first discovered by someone who was looking for a relativistic version of Schrödinger's equation.
The meaning of spin at the classical or first-quantized wave level is described in "What is spin?" by Hans C. Ohanian (Am. J. Phys. 54 (6), June 1986; online here).
• A reason the Dirac equation is called "purely quantum" (and why I would say electron spin is quantum while photon spin has a classical realization in terms of the polarization of the electromagnetic field) is the Pauli exclusion principle. There are no classical spinor fields because you can't take the limit $n\rightarrow \infty$ limit (inside a single field mode) for fermionic fields, in the same way you can take this limit for bosonic fields. Nov 18 '20 at 20:10
• Of course I mean there are no physical classical spinor fields. I know that mathematically you can write a spinor-valued function over spacetime. Nov 18 '20 at 20:22
An essential difference is that there is no representation of spin in ordinary $$3D$$ space$$^\dagger$$. Unlike the spherical harmonics $$r^\ell Y_{\ell m}(\theta,\varphi)$$ which can be expressed in terms of spherical (and eventually Cartesian) coordinates, such a representation in terms of "physical" coordinates is not possible for spin-$$1/2$$ (or half-integered spin in general).
$$^\dagger$$ see Gatland, I.R., 2006. Integer versus half-integer angular momentum. American journal of physics, 74(3), pp.191-192.
The electromagnetic field is often referred to as having spin 1 even in the classical context. This considers "spin" to be defined as the representation of the Lorentz group that a field transforms under. Indeed, according to that definition, every field in classical physics may be assigned a spin (which is possibly but not necessarily zero). The gravitational field of General Relativity has spin 2.
These fields carry intrinsic angular momentum as a consequence of their spin-ful nature: when constructing the conserved Noether currents corresponding to Lorentz transformations—the so-called spin tensor—it is necessary to consider that an active Lorentz transformation $$\Lambda$$ upon the field $$F$$ acts both by "moving" the field through space and upon the components of the field itself. This is done e.g. here in section 8.9.1 for the electromagnetic field. So spin exists in the classical domain in the sense of (1) non-trivial representations of the Lorentz group, (2) a source of additional angular momentum that scalar fields don't possess.
Indeed, some kinds of classical limit of "particle" spin may also be constructed, like the OP's example of a Kerr black hole.
When people say that spin has no classical analogue, they probably are referring to the whole package of weirdness of quantum spin, including the fact that it's quantized and that its components don't commute with each other. If that's the case, then the conclusion obviously follows. | {"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": 28, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9393705725669861, "perplexity": 313.3396462366608}, "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-2022-05/segments/1642320301475.82/warc/CC-MAIN-20220119155216-20220119185216-00018.warc.gz"} |
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Zh. Vychisl. Mat. Mat. Fiz., 1997, Volume 37, Number 11, Pages 1294–1300 (Mi zvmmf1989)
Renumbering strategies based on multi-level techniques combined with ILU-decompositions
E. F. F. Botta, A. van der Ploeg
Groningen, Netherlands
Abstract: In this paper we present an incomplete factorization technique which uses a renumbering of the unknowns, based on a sequence of grids as in multi-grid. For many problems discretised on structured grids, we obtain almost grid-independent convergence when this factorization is combined with some conjugate gradient-like method. Also, a similar preconditioning technique is described which can be used for matrices with arbitrary sparsity patterns as those arising from finite element methods on unstructured grids. During the factorization we use a reordering to guarantee that the diagonal blocks to be inverted remain strongly diagonally dominant. This makes it possible to approximate the needed inverses by only a diagonal matrix, leading to more potential parallelism. The method is demonstrated for a number of test problems and compared to some standard methods.
Full text: PDF file (1363 kB)
References: PDF file HTML file
English version:
Computational Mathematics and Mathematical Physics, 1997, 37:11, 1252–1258
Bibliographic databases:
UDC: 519.612
MSC: Primary 65F10; Secondary 65F35
Language:
Citation: E. F. F. Botta, A. van der Ploeg, “Renumbering strategies based on multi-level techniques combined with ILU-decompositions”, Zh. Vychisl. Mat. Mat. Fiz., 37:11 (1997), 1294–1300; Comput. Math. Math. Phys., 37:11 (1997), 1252–1258
Citation in format AMSBIB
\Bibitem{BotVan97} \by E.~F.~F.~Botta, A.~van der Ploeg \paper Renumbering strategies based on multi-level techniques combined with ILU-decompositions \jour Zh. Vychisl. Mat. Mat. Fiz. \yr 1997 \vol 37 \issue 11 \pages 1294--1300 \mathnet{http://mi.mathnet.ru/zvmmf1989} \mathscinet{http://www.ams.org/mathscinet-getitem?mr=1489503} \zmath{https://zbmath.org/?q=an:0946.65019} \transl \jour Comput. Math. Math. Phys. \yr 1997 \vol 37 \issue 11 \pages 1252--1258
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2. Kopal J., Rozloznik M., Tuma M., “An Adaptive Multilevel Factorized Sparse Approximate Inverse Preconditioning”, Adv. Eng. Softw., 113:SI (2017), 19–24
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## 1 Bewertung für Gym Product 2
1. kowsar
Rimply dummy text of the printing and typesetting industry. Lorem Ipsum has been the ever since the when an unknown printer. | {"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": 0.8607532978057861, "perplexity": 19134.360578805314}, "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-2021-04/segments/1610703509104.12/warc/CC-MAIN-20210117020341-20210117050341-00739.warc.gz"} |
https://forum.zkoss.org/question/30056/listbox-on-ie/?answer=30065 | # listbox on IE
cordero
24
The Listbox object on Firefox appears correctly, but on Internet Explorer I do not see the descriptions of the headers columns. Why?
delete retag edit
## 4 Replies
ziccardi
321 7
Could you provide a code snippets to show us what you do and what you get?
skipper
3
Well, we made the same observation with internet explorer 8. Running in "compatibility mode", the page looks more or less ok, but in "native" mode, listbox headers probably need some work on the CSS-side.
Cheers,
skipper
ziobleed
1 1
i've the same problem
• in firefox on my local machine on Jboss Red Hat Enterprise Application Platform 7 and on a remote (Jboss WildFly 7) is rendered correctly (headers and columns contents are perfectly aligned)
• with internet explorer on my local machine is rendered correctly
• with internet explore 11 loading page from the remote server (JBoss WildFly 7) the columns are mis-aligned with headers
i'm using zk 6.5
i cant upload the images of internet explorer and firefox cause i don't have enough karma
this is the listbox
<listbox id="listboxId" hflex="1"
nonselectableTags="*" mold="paging" pageSize="5"
pagingPosition="bottom"
emptyMessage="empty"
class="listboxDocumenti">
sortAscending="${dataAsc}" sortDescending="${dataDesc}" hflex="5" />
sortAscending="${descrAsc}" sortDescending="${descrDesc}" hflex="10" />
sortAscending="${userAsc}" sortDescending="${userDesc}" hflex="10" />
<checkbox
id="checkboxSelectAllDocuments"
sclass="checkboxSelectAll">
</checkbox>
<!-- pdf -->
</listbox>
thanks and best regards
zb
ziobleed
1 1
i resolved by defining a css rule in the zul page as follow
<style>
tr.z-listbox-faker {position: relative !important;}
</style>
ispired by solution found here in this forum question/86901/grids-column-width-on-explorer/
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https://ubpdqn.wordpress.com/2011/04/28/josephus-revisited/ | # Unkown Blogger Pursues a Deranged Quest for Normalcy
• ## Blog Stats
• 10,531 hits
• ## Tweets
I have been puzzling over the Jospehus problem for step size 2. The wikipedia entry provides the solution for this and insights into its properties. It proves that the number of the last man standing, $f(n)$, is $2 l+1$ where $n= 2^m +l, \quad 0\leq l<2^m$. | {"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": 3, "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": 0.814768373966217, "perplexity": 6461.3169456705045}, "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-2017-26/segments/1498128320270.12/warc/CC-MAIN-20170624170517-20170624190517-00172.warc.gz"} |
http://www.koreascience.or.kr/article/ArticleFullRecord.jsp?cn=HOGHC7_2013_v27n6_81 | Study on Steering Ratio of Four-Row Rigid Tracked Vehicle on Extremely Cohesive Soft Soil Using Numerical Simulation
Title & Authors
Study on Steering Ratio of Four-Row Rigid Tracked Vehicle on Extremely Cohesive Soft Soil Using Numerical Simulation
Kim, Hyung-Woo; Lee, Chang-Ho; Hong, Sup; Choi, Jong-Su; Yeu, Tae-Kyeong; Min, Cheon-Hong;
Abstract
This paper considers the steering characteristics of a four-row tracked vehicle crawling on extremely cohesive soft soil, where each side is composed of two parallel tracks. The four-row tracked vehicle (FRTV) is assumed to be a rigid body with 6-DOF. A dynamic analysis program for the tracked vehicle is developed using the Newmark-$\small{{\beta}}$ method based on an incremental-iterative scheme. A terra-mechanics model of an extremely cohesive soft soil is implemented in the form of the relationships of the normal pressure to the sinkage, the shear resistance to the shear displacement, and the dynamic sinkage to the shear displacement. In order to investigate the steering characteristics of the four-row tracked vehicle, a series of dynamic simulations is conducted with respect to the distance between the left and right tracks (pitch), steering ratios, driving velocity, reference track velocity, lengths of the tracks, and properties of the cohesive soft soil. Through these numerical simulations, the possibility of using a kinematic steering ratio is explored.
Keywords
Four-row tracked vehicle;Steering performance;Cohesive soft soil;Terra-mechanics;Dynamic simulation;Kinematic steering ratio;
Language
Korean
Cited by
1.
직교 배열표를 이용한 심해저 채광로봇 미내로의 주행 특성 연구,이창호;김형우;최종수;여태경;이민욱;오재원;홍섭;
한국해양공학회지, 2014. vol.28. 2, pp.152-159
1.
Study of Deepsea Mining Robot "MineRo" Using Table of Orthogonal Arrays, Journal of Ocean Engineering and Technology, 2014, 28, 2, 152
References
1.
Bode, O., 1991. Simulation der Fahrt von Raupenfahrwerken auf Teefseeboden. doctoral thesis (in German), Univ of Hanover.
2.
Brink, A.W., Chung, J.S., 1981. Automatic Position Control of a 300,000-Ton Ship Ocean Mining System. Proc. Offshore Tech Conf, Houston, Paper 4091.
3.
Hong, S., Kim, K.H., 1999. Proposed Technologies for Mining Deep-Seabed Polymetallic Nodules. Chap 12 Research and Development of Deep Seabed Mining Technologies for Polymetallic Nodules in Korea. Proc. International Seabed Authority's Workshop, Kingston, Jamaica, 261-283.
4.
Hong, S., Choi, J.S., 2001. Experimental Study on Grouser Shape Effects on Trafficability of Extremely Soft Seabed. Proceedings of the 4th Ocean Mining Symposium, Szczecin, Poland, 115-121.
5.
Hong, S., Kim, H.W., Choi, J.S., 2002. A Method for 3-D Dynamic Analysis of Tracked Vehicles on Soft Terrain of Seafloor. Fall KCORE Conference, 149-154.
6.
Hong, S., Kim, H.W., Choi, J.S., Yeu, T.K., Park, S.J., Kim, S.S., Lee, C.H., Yoon, S.M., Kim, J.H., 2011. Design of a Pilot Mining Robot for Deep-seabed Manganese Nodule. Proc. of KSOE conferences 2011, 22-25.
7.
Kim, H.W., Hong, S., Choi, J.S., 2003. Comparative Study on Tracked Vehicle Dynamics on Soft Soil : Single-Body Dynamics vs. Multi-Body Dynamics. Proceedings of the 5th Ocean Mining Symposium, Tsukuba, Japan, 132-138.
8.
Kim, H.W., Hong, S., Choi, J.S., Yeu, T.K., 2006. Dynamic Analysis of Underwater Tracked Vehicle on Extremely Soft Soil by Using Euler Parameters. Journal of Ocean Engineering and Technology, 20(6), 93-100.
9.
Kim, H.W., Lee, C.H., Hong, S., Choi, J.S., Yeu, T.K., 2010. A Study on the Steering Performance of Four-Row Rigid Tracked Vehicle on Extremely Cohesive Soft Soil. Proc. of KSOE conferences 2010, 263-266.
10.
Lee, C.H., Kim, H.W., Choi, J.S., Hong, S., 2009. A Study on the Steering Performance of Four-Row Tracked Vehicle on Extremely Cohesive Soft Soil. Proc. of KSOE conferences 2009, 310-315.
11.
Wong, JY. (1993). Theory of Ground Vehicles. John Wiley & Sons, New York. | {"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": 1, "/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": 0.38034263253211975, "perplexity": 28857.750177492897}, "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-2017-30/segments/1500549426133.16/warc/CC-MAIN-20170726102230-20170726122230-00593.warc.gz"} |
https://docs.adyen.com/pt/point-of-sale/classic-library-deprecation/classic-library-integrations/com-extension-for-windows-integration/com-extension-for-windows-objects/tenderoption | Would you like to contact support?
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TenderOption
Name Description
TenderOption Represents tender options that are passed with the tender. Create the object using CreateTenderOptionObj method from the PedDevice object. Generally, transaction options can be configured via the Adyen Customer Area (CA) or as a TenderOption on a per-transaction basis.
Tender options define the behavior of the PED.
An object of type TENDER_OPTIONS that can have the following values:
NameDescription
AllowPartialAuthorisationFlags that a partial approval is allowed. As a result, the authorised amount might be lower than the requested amount.
AskCharityTriggers the terminal to ask if the shopper wants to donate to charity.
AskGratuityTriggers the terminal to ask if the shopper wants to tip.
BypassPinBypasses PIN entry where the shopper does not know the PIN for the card and the Merchant either knows they are the legitimate cardholder or wants to give them the benefit of the doubt.Requires that the shopper indicates the PIN is not known. The staff cancel the existing transaction and initiate a new transaction through the POS system. They then ask the shopper to press Enter when prompted for a PIN. Subsequently the shopper will need to provide a signature. The Merchant then needs to check the signature and approve it.As a cardholder is expected to know the PIN for the card issued, verifying of the signature as well as cardholder name with some form of identification is recommended.
DontPrintReceiptSpecifies that no receipt should be printed.
EnableMagstripeFallbackIf ICC cannot be processed, magstripe will be used as the point-of-sale entry mode. If magstripe is disabled in your configuration, use this tender option to enable it for a transaction.
ForcedDeclineForces a decline of the transaction, for example, if fraud is suspected.
ForcedOnlineForces online authorisation of the transaction. Should only be used in exceptional cases. The terminal tries to process online by default, and if that is not possible, it checks the configured limits to determine if the transaction can be processed offline.
GetAdditionalDataGathers and makes available additional data, after a card is read. The amount of the transaction can be changed based on additional input from the POS system. Used for Dynamic Currency Conversion and shopper recognition (for example, to offer discounts to loyal customers). To use these features, you need to contact Support for back end configuration.
KeyedEntryTriggers MKE processing. If set to true, this requires the merchant or cardholder to enter the card number manually. Used for damaged cards.
For gift card operations, the tender created before redemption must not include a KeyedEntry tender option. If the original tender contains the KeyedEntry tender option, it is not possible to update the tender to a gift card redemption.
MOTOTriggers MOTO transactions on the payment terminal from the POS system. MOTO transactions are card-not-present transactions, where the payment details are presented to a merchant by a shopper by means of mail (not email), fax, or telephone.
NoCTLSDisables contactless/NFC as entry mode for the transaction.
ReceiptHandlerSpecifies that the POS system handles and prints receipts. If omitted, it is required that the payment terminal prints the receipt. If there is no printer unit, the transaction will fail.
SkipAIDPrioritySkip a card's application identifier (AID) priority. This allows a shopper to select their preferred card application.
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https://crntaylor.wordpress.com/tag/math/ | You are currently browsing the tag archive for the ‘Math’ tag.
This is based on a neat little post that I saw on Simon Frankau‘s blog that I thought I’d provide a few more details on, as well as bringing it to a wider audience.
Some higher-level data structures in object-oriented programming languages have dynamic memory allocation. This is used to create objects (usually things that behave like lists) that can grow and shrink as the program executes.
When initializing a regular array in C or Java, you have to specify the size of the array on creation, for example with
int myArray[] = new int[10];
in Java (actually Java has a wide variety of syntaxes for array creation, which I won’t go into). Importantly, your array has the size you initially specify for the rest of time. When it’s created, you are allocated a sequential block of memory that’s exactly big enough to hold the elements of the array (it’s sequential so that looping through the elements of the array is fast). If you find that you need more storage space at any point in time, you’re out of luck.
Fortunately most high-level languages like provide a data structure which is able to grow, for example C++’s std::vector or Java’s ArrayList and Vector. When these are created they are allocated a block of memory. If it ever turns out that you need more space, then they allocate a new block of memory to allow you to extend the array: for example, if you have an array of size 10 and then try to allocate something to the 11th position:
ArrayList myArray = new ArrayList(10);
myArray.set(10, "foo");
But how much new memory should they allocate?
A little bit of investigation reveals that this varies across languages and across data structures. Commonly, a multiplicative growth factor is applied. For example, with a growth factor of two, you would double the size of the allocated block each time. To ensure that the array elements remain sequential in memory (so that it’s still fast) you probably want to allocate a new block and copy across the elements in the old block – so your strategy works like this:
• Allocate a new block of memory that is bigger than the current block by some factor
• Copy the old data into the new memory block
• Start writing the new elements here
As Simon points out, a natural strategy is to double the size of the array each time, but this is probably a bad choice. This is because at each stage you assign a new memory block of size $2^n$, but the total size of the memory locations used so far (assuming your initial array size is rescaled to be 1) is $1 + 2 + \cdots + 2^{n-1} = 2^n - 1$, so you can’t reuse any of the old memory. Since you’re now only dealing with the newly allocated memory, all this old memory goes to waste.
What would be a better factor? Let’s say we used $x$. Then initially we’d have a block of (rescaled) length 1. We allocate a new block of length $x$. When we extend again we allocate a block of length $x^2$. We need to keep the old block of length $x$ around to copy over the old data, and we can’t fit our block of size $x^2$ in the space of size 1, so we allocate this as a new block too. But when we allocate the next block of size $x^3$, we might be able to fit it in the two old blocks, of size 1 and $x$. This works if
$1 + x = x^3$
which you can solve numerically and find that there is a solution $x\approx 1.32$. What if you were willing to wait for one more allocation before reusing the memory? Then we’d try and fit a block of size $x^4$ into a block of size $1 + x + x^2$, so we solve
$1 + x + x^2 = x^4$
for a solution of $x \approx 1.47$. How about if we were willing to wait for $n$ allocations? Then we’d be trying to solve
$1 + x + \cdots + x^{n-2} = x^n$
which is more tricky. However, if we notice that the left-hand side is a geometric series, then we can sum it up and multiply through to get
$x^{n-1} - 1 = x^{n+1} - x^n$
This still looks a but hopeless, but when $n$ is large the three terms involving $x$ will dominate the ‘-1’ and we can neglect it. This corresponds to an allocation strategy where we know that we will be able to reuse a block of memory at some point in the future. We get:
$x^{n-1} = x^{n+1} - x^n$
This is looking more hopeful. Now we can divide by $x^{n-1}$ and rearrange, giving a familiar-looking equation:
$x^2 - x - 1 = 0$
Why does this look so familiar? It’s positive solution is exactly $x = \tfrac{1}{2}(1 + \sqrt{5}) \approx 1.618\dots$, the well-known golden ratio! Now, you wouldn’t want to use exactly this value to do your memory reallocation, because you’d end up waiting forever to be able to reuse your old memory. But Simon suggests that a strategy of using a number a bit less than this, say 1.5, might work out.
And guess what? Java’s ArrayList uses exactly this factor to allocate new memory. I don’t know if it reuses its previously allocated memory in the style described here – that’s something to find out for the future.
I have a lot of coin-tossing problems floating around in my head, of varying levels of difficulty. Here’s one which requires some thought, but shouldn’t present too much of a challenge if you’ve seen this kind of problem before.
You start flipping a fair coin, and keep going until you’ve seen n heads in a row, when you stop. On average, how many times do you flip the coin before stopping?
This is what spaghetti looks like
Here’s a nice problem in probability. I like it because at first sight it seems fiercely complicated, but thinking about it in the right way makes it seem much simpler.
You have a bowl filled with n strands of spaghetti. You pick two ends from the bowl at random, and tie them together. You keep doing this until there are no more loose ends. Obviously, you will have made some number of loops when you reach the end of this process.
What is the average number of loops created?
Let’s play a game. I pick a number — any number at all (whole number, fraction, whatever). I then flip a coin to decide whether to add 10 or subtract 10 from it, and I tell you the result. You win the game if you can tell me what my original number was.
For example, suppose the number I picked was 31. I flip a coin, getting heads, and therefore add 10, getting 41, and that’s the number I tell you. Now you know that I picked either 31 or 51. It seems that you have no way of deciding between those, so your chance of winning the game is 1 in 2.
I contend that you can win the game with a probability of greater than 1 in 2, although I will admit that I can’t tell you how much greater the probability is.
Let’s introduce a bit of terminology. We’ll call the first number that I pick X. This is the number that you’ve got to guess. Then I flip a coin and add or subtract 10 from it, getting Y, which is the number I tell you. So we know that Y = X + 10 or Y = X – 10.
The secret to you winning the game is to pick your own number, Z, before I tell you Y. It doesn’t matter how you pick Z, so let’s just say that you have a computer program that generates a random number for you (from the standard normal distribution, if you want to get picky).
Now you play the following strategy:
• If Y < Z then you guess that X = Y + 10 (ie I subtracted 10)
• If Y > Z then you guess that X = Y – 10 (ie I added 10)
I claim that this strategy will win you the game more than half the time. To see why, we have to consider three cases:
1. If X < Z – 10 then we always have Y < Z, so you guess X = Y + 10 and get it right 1 time in 2.
2. If X > Z + 10 then we have Y > Z, so you guess X = Y – 10 and get it right 1 time in 2.
3. But if X is in the interval [Z – 10, Z + 10] then your guess will always be right. If X = Y – 10 then we always have Y > Z, so you guess X = Y – 10, which is right. And if X = Y + 10 then we have Y < Z, so you guess X = Y + 10, which is right.
As long as there is some chance that X is in this interval, then there is a greater than 50% chance of you winning the game.
I’m flat hunting at the moment. This is possibly one of the most infuriating tasks to undertake, especially if you’re doing it in London, where the property market moves so fast that you can hear of a property coming onto the market in the morning, make an appointment to see it in the afternoon, and get a call at lunchtime to say that it’s been taken already.
But I have good news! My flatmate and I found a great place in Wapping, we’ve made an offer on it and we’re just waiting to see if that goes through. In the process, an interesting little puzzle came to light that I thought I’d share with you.
Like most two bedroom flats, the apartment we’ve seen has a master bedroom and a second bedroom. The master bedroom is better in every way — it has an ensuite bathroom, it’s about 50% larger, it looks cooler and it has a TV built into the wall. Obviously, both of us would prefer to have that room over the smaller room.
The question is, what’s the fairest way to decide which of us gets that room? We’re willing to split the rent up differently, but how should we decide on an appropriate split that leaves us both happy now and, more importantly, will leave us both happy for the foreseeable future?
Both me and my flatmate are ex-mathematicians, and thus are willing to put up with almost any amount of complicated wrangling if it means that we get to the right answer – so feel free to make it as involved as you like.
A little while back, science punk Frank Swain posted a mathematical puzzle on his blog. The puzzle can be described simply — space n points equally around the unit circle, and draw all possible lines connecting those points. How many triangles are there in the resulting graph?
The first couple of cases, n = 3 and n = 4 are easy — the answers are 1 and 8. For n = 5 it requires a little more thought, but stand-up mathematician Matt Parker has a very clear explanation of why the answer is 35 on his website.
The six-sided mystic rose
After that, it gets progressively more difficult to count the triangles. The diagram for n = 6 is on the right. Try keeping track of all those triangles in your head (although CloudoidLtd has a very pretty, and easy to understand, solution for n = 6 and n = 7 on his blog.) The answers there are 110 and 287.
I was inspired by a comment on Frank’s blog to try a more traditionally combinatorial approach to solving the problem. The key observation is that each triangle is made up of exactly three chords. These chords can intersect at one of the points around the circle, or they might intersect somewhere inside the circle. We just have to classify the different ways that three chords can intersect to form a triangle, and then count up how many there are in each case.
A guide to choosing
The explanation will require that we understand how to calculate the number of ways of choosing a set of k objects from a larger set of n objects. We use the notation (n,k) as a shorthand for this. We pronounce it “n choose k“, and we definite it mathematically by
(n,k) = n! / k! (n-k)!
The exclamation mark is the factorial function, which means that we multiply together every number from n all the way down to 1, so that for example 4! = 4 x 3 x 2 x 1 = 24 (we also have the useful convention that 0! = 1). If you’ve not seen this before, it can be a fun exercise to try and work out why (n,k) has to take this form.
Counting the triangles
We’re trying to count the number of ways that three chords of the circle can intersect to form a triangle. Each chord involves two points around the circle, so there are only four cases to consider:
Triangle with 3 points
1. The chords form a triangle between three points. This is the simplest case to consider. Every set of three points around the edge of the circle contributes one triangle, so the number of triangles is simply the number of ways of choosing 3 objects from a set of n objects, which is (n,3).
Triangle with 4 points
2. The chords form a line connecting four points. There are (n,4) ways of choosing a set of four points, and for each set of four points there are four ways we can arrange the chords so that they form a triangle. So this contributes another 4 * (n,4) triangles.
3. Two of the chords share a point, and the third chord cuts across them. This involves five points in total. There are (n,5) ways of choosing 5 points, and for each set there are five ways to arrange the chords so that they form a triangle. This contributes another 5 * (n,5) triangles.
Triangle with 5 points
4. None of the chords share a point, so there are six points in total. To make a triangle we have to join opposite points, so there is only one way of arranging the chords so that a triangle is formed. This gives another (n,6) points.
With all of this counting done, we have a formula for the number of triangles formed by the mystic rose with n points, which we denote by T(n):
T(n) = (n,6) + 5 (n,5) + 4 (n,4) + (n,3).
So how does this formula stack up when we compare it to the results we already know? With suitable adjustments for when n < 6 (because (n,k) is meaningless when k > n) we get
T(3) = 1, T(4) = 8, T(5) = 35, T(6) = 111, T(7) = 287 and T(8) = 644.
This works for most of the cases, but the actual answers for n = 6 and n = 8 are 110 and 632. The formula overcounts by one triangle for the 6-sided rose, and it overcounts by 12 triangles for the 8-sided rose. What’s going on?
Overcounting, and why the problem is hard
We can see the problem by looking at the 6-sided rose at the beginning of the post. The three chords which cut the circle in half all meet at the center. They don’t form a triangle, but our formula treats them as if they do. This is why it overcounts by 1.
It’s interesting to note that if the points weren’t equally spaced around the circle, but instead were randomly spaced, then we wouldn’t have this problem. It’s unusual for three lines in a plane to all intersect at the same point — it requires some special structure, and in this case the special structure is given by demanding that all the points lie on the vertices of a regular polygon. Injecting some more randomness into the problem would actually make it easier. The problem would be one of pure combinatorics — that is, just a problem of counting. Because of the additional regularity, we have made it a problem of geometry. Not only do we have to think about how the points are connected by lines, we also have to worry about the exact locations of the points. This is why the mystic rose puzzle is hard!
Finding the intersections
Whenever we have three or more chords intersecting at a point inside the circle, our formula is going to overcount the number of triangles, so we need to correct for this somehow.
Intersections at the center of the circle are easy to deal with. When there are n points, and n is even, then there are n/2 chords which pass through the center of the circle. Each set of three chords contributes one false triangle, and there are (n/2,3) ways of choosing 3 chords from a set of n/2, so we can modify our formula to:
T(n) = (n,6) + 5 (n,5) + 4 (n,4) + (n,3) – a(n) (n/2,3)
where a(n) = 1 if n is even, and a(n) = 0 if n is odd. This formula now gives the correct result for n = 6, although it still fails for n = 8.
A number of interesting hypotheses spring to mind, which would simplify the problem if they were true:
1. The intersections only occur at the center of the circle.
2. The intersections all occur along lines joining two points at opposite sides of the circle.
3. The intersections all occur along symmetry axes of the rose.
4. Except at the center, only three chords ever intersect at one point.
Unfortunately, none of these is true. Hypothesis 1 can be seen to be untrue if you look at the 8-sided roses in the pictures above. Around the center of the rose there are 8 points where three chords intersect. These explain 8 of the overcounted triangles. The other 4 are from the intersection of four chords at the center — every set of three chords intersecting at the center gives a false triangle, and there are (4,3) = 4 ways of choosing a set of three chords from four.
To see why Hypotheses 2 and 4 are false, we have to look at the 12-sided rose. Using the mystic rose drawer at nrich you can draw mystic roses with up to 20 points. For the 12-sided rose pictured on the right, we see that there is an intersection of 4 chords which doesn’t occur along a line joining two points on opposite sides of the circle. Damn!
The 4-chord intersection
To see why Hypothesis 3 is false, we have to look at the 16-sided rose. Now the three-point intersection doesn’t occur on a symmetry axis (can you see it? It’s in the top left quadrant of the picture). This means that this intersection is repeated 32 times around the circle, rather than the 16 times that we’d see if the intersection was on a symmetry axis.
A 3-chord intersection for n = 16
One hypothesis that does seem to be true is this one:
5. When n is odd, there are no intersections of three or more chords.
This means that our formula should work for all odd n, and indeed for every n that I’ve checked, the formula holds. I still don’t have a proof, though!
With all of these hypotheses rejected, we have to come up with a criterion for the intersection of three or more chords of the circle, and a way of determining how many such intersections there are when there are n points spaced equally around the edge of the circle. This is to come in Part II of this blogpost.
My favorite kind of puzzles are those which sound like they’re going to be an absolute nightmare, but turn out to have a particularly beautiful solution. They’re even better if you don’t really need to know any math to solve them. Here’s such an example, which absolutely delighted me when I first solved it.
An irrelevant picture
I presented it to two of my friends on a long train journey — one of them is a mathematician (in fact he’s a research fellow at Queens’ College, Cambridge) and the other works for a pharmaceuticals company. The non-mathematician got it first. It really is a problem that anyone can have a crack at.
First, I’ll describe a warm-up puzzle. It’s kind of a barometer for the real puzzle.
The challenge: produce a deck of cards, each with a whole number painted on it, with which you can make any number between 1 and 1 million, by picking out some of your cards and adding together the values. You should do this with the least number of cards possible.
Got that? You may want to stop reading and think about it for a second, because the solution is coming up in the next paragraph. I’ve found that computer scientists and programmers tend to get this one faster than most people — often with less than a second’s thought.
The answer is that you should label your cards with the powers of two, so that your deck starts 1, 2, 4, 8 … If you didn’t come up with this solution, the way to think about it is to figure out what cards you’d need to make each of the numbers from 1 up to 1 million. You need to be able to make 1, so you’d better have a card labeled ‘1’. Similarly you need a card labeled ‘2’. But with those two cards you can already make 3, so the next card that needs to be added to your deck is labeled ‘4’. After a while you should spot the pattern, and come up with an argument for why this will work for every number up to a million.
Now here’s the real puzzle, which is a bit more tricky, but fun to think about. I’m not going to give the answer now — I’ll post it in a couple of days.
Produce a deck of cards with which you can make any number between 1 and a million by picking cards and adding together their values, even if you have lost one of the cards in the deck.
The requirement that your deck is insensitive to the loss of a card makes the problem tricker to think about, but a similar approach to that described for the easier problem can work. For example, you know that you need to include two cards labeled ‘1’, so that even if you lose one of them you can still pick cards that add up to give 1.
For those inclined to a challenge, there are three levels of answer:
1. Describe the deck of cards that solves the puzzle (easy, requires almost no math.)
2. Prove that you can make any number between 1 and a million, even if you lose a card (not too hard, requires a little bit of math.)
3. Prove that this is the minimal deck of cards that solves the puzzle (difficult, but still needs no math beyond high school.)
I learned this from my office mate, Toby Wood, but I’m not certain where he got it from. If you know, please leave a comment!
My last post, on the 17 x 17 challenge, ended with a solution to a problem which I thought sounded incredibly naïve* but which turned out to be correct. It got me thinking about a problem that I was posed when I was interviewing to work at investment banks. In fact I was asked the same question in interviews for two different banks (potential applicants take note).
Sketch of the problem as presented to me
It goes like this: You find yourself in a dark cave, which has three tunnels leading from it (see the crude sketch on the right). One of the tunnels leads outside, and it takes 3 hours to traverse it. The other two tunnels connect to each other, returning you to the cave, and they take 1 hour to walk down. If you choose tunnels at random each time you’re faced with a choice, how long will it take you on average to get outside?
I’m about to tell you the answer, so maybe you want to stop and think about it for a bit. The point I’m making is that even though the calculation you have to do is a bit involved (although simple to anyone who’s ever studied Markov chains) there’s a cheeky shortcut: you can get the answer just by assuming that you take each of the tunnels once, and add up the times to traverse them, getting an answer of 1+1+3=5 hours.
Is this just a coincidence? To find out, let’s generalise the problem. Now we find ourselves in a cave with n tunnels, of which m of them lead to an exit and n-m dump you back in the cave. Each of the tunnels takes time $\tau_i$ to traverse, for i=1,…,n, and is chosen with probability $p_i$. We’ll adopt the convention that the first m tunnels are the ones that lead to an exit, and the last n-m are the return tunnels (notice that our generalisation allows the possibility that a return tunnel might take a different amount of time to traverse if we go in the opposite direction).
To work out what the average escape time is, we notice that if we pick an escape tunnel then we’re free in the time it takes to traverse the tunnel. If we pick a return tunnel, then we’ve increased our expected time to leave by the time that it took to traverse the tunnel. If the time to leave is T, then we write the expected leaving time as E[T], and
$E[T] = \sum_{i=1}^m p_i\tau_i + \sum_{j=m+1}^n p_j(\tau_j + E[T])$.
After a couple of lines of algebra we see that the expected time to leave is given by
$E[T] = (\sum_{i=1}^n p_i\tau_i) / (1 - \sum_{j=m+1}^n p_j)$
or, written in everyday language:
Avg time to leave = (Avg tunnel length) ÷ (Chance of picking an exit tunnel)
That’s it! The average time to escape only depends on the average time it takes to traverse a randomly picked tunnel, and the probability of picking a tunnel which leads to an exit. It’s completely insensitive to the specifics of the problem, namely how long the individual tunnels are, and what the precise probabilities of picking each tunnel are. In the special case where each of the tunnels is equally likely, all you have to do is add up the time it takes to traverse each of the tunnels, and divide by the number of tunnels that lead to an exit.
This appeals to me because a problem which has a lot of fine detail turns out to be insensitive to the fine detail. I’d be interested to hear about other examples of this phenomenon.
* Is it pretentious to write ‘naïve’ instead of ‘naive’? Answers, opinions and furious rants on a postcard, please.
A recent post on bit-player drew my attention to William Gasarch’s 17 x 17 rectangle challenge. In short, Gasarch is offering $289 (289 = 17 x 17) for the solution to the following puzzle. A coloring of a 6 x 6 grid which satisfies the 'no rectangles' constraint. The problem is to take a rectangular n x m grid, and color each of the squares with one of four colors, so that there are no rectangles in the grid whose corners all have the same color. For example, on the right you can see a 6 x 6 grid which satisfies this constraint. It turns out that if the size of the grid is 19 x 19 or bigger, then you can prove that it’s impossible to color the grid without creating a rectangle. In all cases up to a 16 x 16 grid, Gasarch has an example of a coloring that satisfies the no-rectangles constraint. However, the 17 x 17 and 18 x 18 cases are still open. To win the$289, you need to send Gasarch an example of a rectangle-free coloring of the 17 x 17 grid.
If it turns out that it’s possible to color the grid in this way, then the proof that you can do so is simple — you just draw a picture of the coloring (it’s easy to get a computer to check that it doesn’t have any rectangles). However, if it turns out to be impossible then it can be very hard (read: long and ugly) to prove that that’s the case. This is why the problem is so appealing to people with very little experience in mathematics: to solve the problem, all you have to do is draw a picture!
Of course, it’s easier said than done. There are $4^{289}$ different ways to color a 17 x 17 grid, and very few of them will be rectangle free. If you were to write a computer program to check all possible colorings, it would take longer than the age of the universe to run.
My first thought after reading the bit-player post was that a simulated annealing algorithm might do the trick. Simulated annealing is a computational technique which is based on the way that metals can be cooled slowly in order to minimize the number of defects, effectively finding a minimal energy solution to the problem of arranging the atoms in the metal. Simulated annealing tends to work well in situations that have a large number of possible states, and a large number of local minima — just as the rectangles problem does.
I’m working on this algorithm at the moment, and hopefully I’ll have a post about that in the near future. But while I was thinking about the problem, I became distracted by another question: if you color the grid randomly, how many same-color rectangles do you create on average? It’s easy to write a compute program that uses Monte Carlo to approximate this number, but I wanted to do it analytically.
It seems to be a difficult problem, because each cell in the grid can potentially be part of many rectangles. It seems as though there’s a lot of interdependence between the colors of different cells, which will make the calculation very difficult indeed.
Undeterred, I decided to try a naive calculation, in the hope that even though it was wrong, it wouldn’t be too wrong, and it would give me some insight into how to do the full calculation. First I worked out how many rectangles it’s possible to make on an n x n grid by joining corners. After some thought, you can see that this number N is given by:
$N = \sum_{i=1}^{n-1} \sum_{j=1}^{n-1} (n-i)(n-j) = \tfrac{1}{4}n^2(n-1)^2$
For each potential rectangle, to be counted it needs all four of its corners to be the same color to be included in our count. Each cell has a probability of 1/4 of being any particular color, so the probability of getting all four the same is $(1/4)^4$, but this could happen with any of the four possible colors, giving a total probability of $4(1/4)^4=1/64$. Therefore, according to this dodgy calculation, the average number of rectangles R in an n x n grid is
$R = N/64 = \frac{n^2(n-1)^2}{256}$
So how does this rough calculation compare with the numerically computer results? Take a look for yourselves. The dots are the numerical approximations (which should be pretty accurate) and the dashed line is the formula I derived above:
Average number of rectangles plotted against grid size.
It turns out that this formula gives precisely the right value for the expected number of rectangles in a random coloring! So now my question is: is it actually the case that, for some subtle reason, the calculation I did above is valid after all, even though intuitively it seems that it should be completely wrong? Or is it just a coincidence that it comes out with exactly the right answer? I may be thinking about this one for a while.
Everyone knows that movie sequels nearly always suck, and that trilogies are the worst of the bunch. If you want a sure-fire way to ruin a good movie, then make two sequels.
But how does this piece of folk knowledge really hold up? I decided to investigate this afternoon, and work out quantitatively (using science) just how bad the second and third movies in a trilogy are.
My first task was to make a list of trilogies — using a combination of asking my friends on Twitter and my officemates, I got a list of 38 well known trilogies, including The Godfather, Jaws, Star Wars (I-III and IV-VI) and Die Hard. I then visited the IMDB page for each movie and recorded its aggregate score out of ten. These could then be plotted on a graph, to indicate visually just how much sequels suck:
Ratings out of ten for 38 movie trilogies.
One unsurprising result is that the second movie in a trilogy tends to be worst than the first, and the third movie tends to be worse than both of those. The average rating for the first movie was 7.58, as compared to 6.82 for the second movie and 6.38 for the third.
Something a bit more surprising is that the second and third movies in a trilogy aren’t uniformly worse — instead there tends to be more of a spread in quality, whereby second movies are much more variable in quality than first movies, and third movies are even more so. This can be seen in the standard deviations of the ratings: 0.73 for the first movie, 1.2 for the second movie and 1.4 for the third.
Finally, as with any rule, there are exceptions. The most striking is Sergio Leone’s Man With No Name trilogy, comprising A Fistful of Dollars, For a Few Dollars More, and The Good, The Bad and the Ugly. Each of these movies was better than the last, with the third movie getting an average rating of 9.0, the highest of any third movie in a trilogy.
Similarly, The Lord of the Rings maintained high ratings throughout, with the third movie being rated the best of the trilogy, although in this case the effect isn’t as dramatic. It’s noticeable that with both these exceptions, the three movies were conceptualized as a trilogy, planned that way from the beginning, rather than the second and third movies being made to cash in on the success of the first. Perhaps there is something to artistic merit after all.
I can make the full data set available on request, if anyone thinks they can do something cool with it. | {"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": 32, "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": 0.6165351271629333, "perplexity": 319.9754841100994}, "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-2017-17/segments/1492917125654.80/warc/CC-MAIN-20170423031205-00398-ip-10-145-167-34.ec2.internal.warc.gz"} |
http://mathhelpforum.com/discrete-math/20246-binomial-random-variables.html | ,
,
# a scalper is considering buying tickets for a particular game. the
Click on a term to search for related topics. | {"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": 0.31889185309410095, "perplexity": 2314.1551442627315}, "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-2017-22/segments/1495463608956.34/warc/CC-MAIN-20170527152350-20170527172350-00013.warc.gz"} |
http://tex.stackexchange.com/questions/141822/remove-title-in-biblatex-references | # Remove title in biblatex references
I want to cite articles as full reference, but only in the text. So far, everything works in the MWE below, but there is still the title of the article which I want to suppress.
One way I found to do this was by adding \DeclareFieldFormat[article]{title}{}; but that cancels the title and leaves two commas (,,) where the title has been.
Another suggestion was to use \AtEveryBibitem{\clearlist{title}}, but that doesn't seem to work at all.
Does anyone know how to get rid of the title? Such that the citations become
I want to cite Author et al. (2050), Journal A, 50, 63–90 as well as Author (2013), Journal B, 50, 63–90
Here is a minimum working example:
\documentclass{scrartcl}
%%%%%%%%%%%%%%%%%%%%%%% THE REFERENCES %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@article{entry1,
author = {Author, A. and Buthor, B. and Cusor, C.},
title = {Title A},
journal = {Journal A},
volume = {50},
year = {2050},
pages = {63--90},
}
@article{entry2,
author = {Author, A.},
title = {Title of Article B},
journal = {Journal B},
volume = {50},
year = {2013},
pages = {63--90},
}
\end{filecontents}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%% BIBLIOGRAPHY STYLE %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\usepackage[style=authoryear,maxnames=1,backend=bibtex,doi=false,isbn=false,url=false]{biblatex}
\DeclareFieldFormat[article]{volume}{\mkbibbold{#1}}
\DeclareFieldFormat[article]{number}{\mkbibparens{#1}}
\DeclareFieldFormat{journaltitle}{\mkbibemph{#1},} % italic journal title
\DeclareFieldFormat{pages}{#1}
%\DeclareFieldFormat[article]{title}{} % remove title
\renewbibmacro{in:}{} % remove "in"
\renewcommand{\mkbibnamefirst}[1]{} % remove first name
\renewcommand{\newunitpunct}{, }
%%%%%%%%%%%%%%%%%%%%%%%%%%%%% BEGIN THE DOCUMENT %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{document}
I want to cite
\fullcite{entry1}
as well as
\fullcite{entry2}
\end{document}
-
Try \AtEveryBibitem{\clearfield{title}}. title is a field not a list. But it is not a good idea to not display the title, I think (see the comments to this question). \DeclareFieldFormat[article]{title}{} is not really something one should do, as biblatex still thinks it prints the title even though it did in fact not do that. – moewe Nov 1 '13 at 19:38
@moewe No, that doesn't work, but I just found a solution. It seems one needs to redefine the "Driver", i.e. \DeclareBibliographyDriver{article}{\printnames{author} \newunit \printfield{year} \newunit \printfield{journaltitle} \newunit \printfield{volume} \newunit \printfield{pages} \finentry} – John Smith Nov 1 '13 at 19:42
Weird it works for me... Just to reiterate: You want to use \fullcite with title and \printbibliography without? If you want \fullcite to ignore the title, go with \AtEveryCitekey{\clearfield{title}}. Please do not redefine the driver in such a minimal way. – moewe Nov 1 '13 at 19:46
@moewe hm strange, now it seems to work as you wrote. Not sure what I did wrong before. And I want to only cite the articles in the text, but with full reference and not have \printbibliography at all – John Smith Nov 1 '13 at 19:48
@moewe: there seems to be some extra space before the citations, particularly visible if I do (\fullcite{entry1}). Do you know how to get rid of that? – John Smith Nov 1 '13 at 19:56
One really should not suppress fields via \DeclareFieldFormat{title}{}, as biblatex will still think it printed the title field, though it really did not do that. This will result in superfluous and spurious spaces and punctuation.
If you want to get rid of the title information in a citation, go with
\AtEveryCitekey{\clearfield{title}}
to delete the information in the bibliography, it is
\AtEveryBibitem{\clearfield{title}}
Similarly, \renewcommand{\mkbibnamefirst}[1]{} is not the best idea to suppress first names, you might try
\DeclareNameFormat{first-last}{%
\usebibmacro{name:last}{#1}{#3}{#5}{#7}%
\usebibmacro{name:andothers}}
here (see also Biblatex: Last name only in \footcite for other solutions).
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http://djtrichrome.com/nef15x4/track-modulus-is-defined-as-formula-c8353b | # track modulus is defined as formula
We can write the expression for Modulus of Elasticity using the above equation as, E = (F*L) / (A * δL) So we can define modulus of Elasticity as the ratio of normal stress to longitudinal strain. The bulk modulus of a material may be measured by powder diffraction, using x-rays, neutrons, or electrons targeting a powdered or microcrystalline sample. This formula, over 100 years old, matches the results of state-of-the-art finite element analysis with pipe-soil interaction. A 1 meter length of rubber with a Young's modulus of 0.01 GPa, a circular cross-section, and a radius of 0.001 m is subjected to a force of 1,000 N. In the formula as mentioned above, “E” is termed as Modulus of Elasticity. The modulo (or "modulus" or "mod") is the remainder after dividing one number by another. The Modulo Operation Expressed As a Formula; Use Cases for the Modulo Operation. A rail is subjected to heavy stresses due to the following types of forces. This is accomplished by the rail acting as a continuously supported beam, distributing the load across several ties. Young’s Modulus or Elastic Modulus or Tensile Modulus, is the measurement of mechanical properties of linear elastic solids like rods, wires, etc. Track limits are essentially defined based on the intended layout of the track. This chapter reviews the investigations of the dynamic modulus of elasticity of a track in ballast with regard to high speeds. Publisher Summary. Fritz Birmann, in Railroad Track Mechanics and Technology, 1978. (b) Lateral forces due to the movement of live loads, eccentric vertical loading, shunting of locomotives, etc. Given an integer n > 1, called a modulus, two integers are said to be congruent modulo n, if n is a divisor of their difference (i.e., if there is an integer k such that a − b = kn).. Congruence modulo n is a congruence relation, meaning that it is an equivalence relation that is compatible with the operations of addition, subtraction, and multiplication. σ is the Stress, and ε denotes strain. (a) Vertical loads consisting of dead loads, dynamic augment of loads including the effect of speed, the hammer blow effect, the inertia of reciprocating masses, etc. Bulk Modulus Formulas . It may be calculated using the formula: Definition of . In this article, we will discuss its concept and Young’s Modulus Formula with examples. Section Modulus calculator uses Section Modulus=(Breadth of the Section*Height of the Section^2)/6 to calculate the Section Modulus, The Section Modulus formula is defined as a geometric property of the cross section used for designing beams and flexural members. Dividing this equation by tensile strain, we obtain the expression for Young’s modulus: The modulus operator, written in most programming languages as % or mod, performs what is known as the modulo operation. You next response, understandably, might be, “That doesn’t clarify anything,” so let’s take a closer look: How It Works. Young’s modulus $$Y$$ is the elastic modulus when deformation is caused by either tensile or compressive stress, and is defined by Equation \ref{12.33}. function of the track support, which is generally defined in terms of the vertical track modulus (lb/in/in). The evaluation of the effects of surcharge loads on buried pipes can be addressed using the Iowa formula. Forces Acting on the Track . Example: 100 mod 9 equals 1 Because 100/9 = 11 with a remainder of 1 Another example: 14 mod 12 equals 2 Because 14/12 = 1 with a remainder of 2 At most tracks, a white line traces the exterior of curbs in corners; that white line represents the track limit. 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http://bmcorser.github.io/2015/12/01/learning-by-rote.html | # Learning by rote
## :sunglasses:
Calculus is full of formulae. As a mundane necessity of examination sometimes those formulae must be committed to memory. I remember remembering . On first sight, it looked huge! How would I ever be able to reproduce something so arcane just from memory? After I looked again, it didn’t seem so bad.
After a period, I had it down pat.
Because these were the GCSE days, when much learning seemed like repetition “until it sinks in” without really understanding the significance of the thing, we learned by rote. This was before the politics of how something was learned would have struck any kind of chord with us; we just wanted to be outside.
It seems the time for learning by rote has come round again, this time with a vengeance. Now I need to get down not one, not two, but twelve formulae (granted, they are simple compared to the quadratic formula, but still).
How am I going to drum that lot into my head? I could print it out on a pocket-sized sheet of paper and gaze lovingly at it when on the tube. Better yet, I’m an adult now, so I could just get it tattooed to my wrist. But wait, why not use the computer to do the drumming for me.
I want to be asked what the corresponding function is for a derivative and what the derivative for a function is at regular intervals. Why don’t I just modify my shell to ask me to give an answer before I am allowed to carry on.
Not being able to respond that the derivative of is within a few seconds would begin to burden my productivity if I didn’t start learning ...
Challenge accepted!
The issue is that if I’m being asked the question in the terminal, then I’ll have to cope with doing the translation of the LaTeX markup in my head. It would be quite nice to display a little X window with a pretty, rendered SVG.
Unix philosophy to the rescue; there’s a little binary that comes with ImageMagick that can do what we want.
The behaviour is going to be dead simple; when a new shell is invoked, open a window showing a random SVG of some , wait for the window to be closed, wait for some LaTeX input, check aforementioned input against the expected value. If the answer is correct, exit. If the answer is wrong then show the correct answer along with the question , wait for the window to be closed, exit.
The first job we have is to put together a table of questions, answers in LaTeX markup and render SVGs for the questions and the questions with their answers .
f(x) f'(x)
x^n nx^{n - 1}
\sin x \cos x
\cos x -\sin x
\tan x \sec^2 x
\sec x \sec x\tan x
\mathrm{cosec} x -\mathrm{cosec} x \cot x
\cot x -\mathrm{cosec}^2 x
e^x e^x
\ln x \frac{1}{x}
\arcsin x \frac{1}{\sqrt{1 - x^2}}
\arccos x -\frac{1}{\sqrt{1 - x^2}}
\arctan x \frac{1}{1 + x^2}
Luckily, I’ve got some code hanging about that will take a LaTeX string like we have above and return an SVG string with the notation I need to be able to recognise. I just need to loop through the table above spitting out SVG files for questions and questions with their answers .
Because I don’t really want to write out a file called \frac{1}{1 + x^2}, I’m just going to make a short hash of the LaTeX string and use that as the file name. I can use the same idea to check the veracity of the answer provided.
So, let’s represent the above as a mapping in Python, and render the SVGs we need:
from bade.directives.eqtexsvg import eqtexsvg
import hashlib
fx_fdx = {
'x^n': 'nx^{n - 1}',
'\\sin x': '\\cos x',
'\\cos x': '-\\sin x',
'\\tan x': '\\sec^2 x',
'\\sec x': '\\sec x\\tan x',
'\\mathrm{cosec} x': '-\\mathrm{cosec} x \\cot x',
'\\cot x': '-\\mathrm{cosec}^2 x',
'e^x': 'e^x',
'\\ln x': '\\frac{1}{x}',
'\\arcsin x': '\\frac{1}{\\sqrt{1 - x^2}}',
'\\arccos x': '-\\frac{1}{\sqrt{1 - x^2}}',
'\\arctan x': '\\frac{1}{1 + x^2}',
}
hashes = {}
for fx, fdx in fx_fdx.items():
# write f(x) to file
fx_hash = 'q-' + hashlib.sha1(fx.encode('utf8')).hexdigest()[:7]
fx_svg = eqtexsvg("\$${0} \$$".format(fx), inline=False)
with open(fx_hash, 'w') as fx_fh:
fx_fh.write(fx_svg)
# write f(x) = f'(x) to file
fdx_hash = hashlib.sha1(fdx.encode('utf8')).hexdigest()[:7]
fdx_svg = eqtexsvg("${0} = {1}$".format(fx, fdx), inline=False)
with open(fdx_hash, 'w') as fdx_fh:
fdx_fh.write(fdx_svg)
# remember association of hashes
hashes[fx_hash] = fdx_hash
for fx_hash, fdx_hash in hashes.items():
print("{0} {1}".format(fx_hash, fdx_hash))
Easy-peasy. A bunch of files just got written to the directory we ran the script in and the script printed a pretty map that tells us about the associations between the files that were written:
q-189199f c65ec7a
q-5600f00 d849a01
q-67fd40d 5600f00
q-a297bb9 b82f717
q-43630ee 61d8e53
q-26d1990 566261d
q-1624dce 1624dce
q-bd04e97 d261fd4
q-d6d9338 5edd4ce
q-0741fac e9e9dc6
q-4f1ae87 2ba2cbb
The q- prefix is to cover the case where an answer is the same as the question (ie. ).
Now to write the program to flash these images and check answers. Because this is going to frequently interrupt me whilst I am doing things, it needs to be pretty snappy if it’s not going to be get on my nerves. So, let’s write it in Rust. We can do that by mostly copy‘n’pasting code from documentation.
Let’s represent our above associations between question and answer with a std::collections::HashMap, almost as nice as writing a literal :wink:
let mut fx_fdx = HashMap::new();
fx_fdx.insert("q-0741fac", "e9e9dc6");
// ...
fx_fdx.insert("q-d6d9338", "5edd4ce");
We also need to randomly select from the above, there’s code in the crate docs for doing that, and we can has a destructuring assignment like Python and ES6:
extern crate rand;
let (fx, fdx) = sample(&mut rng, fx_fdx, 1).pop().unwrap();
Next we need to flash images using display, for which we use std::process::Command in Rust. We’ll need to do this for both questions and answers, so let’s write a function taking a file name:
fn display (name: &str) {
Command::new("display")
.arg("-border").arg("10")
.arg("-bordercolor").arg("white")
.arg(name)
.output()
.unwrap_or_else(|e| { panic!("{}", e) });
}
This function doesn’t actually need to return anything, since we just halt execution whilst the user (me) looks at the image being flashed up. Again, getting input from the user is just :spaghetti: from the docs. I won’t reproduce it here. Once we have the answer provided, we need to hash it and compare the obtained hash with the expected hash. Another tiny function, writ large:
extern crate sha1;
use sha1::Sha1;
fn compare (input: String, fdx: &str) -> bool {
let mut input_sha1 = Sha1::new();
input_sha1.update(input.as_bytes());
fdx.as_bytes() == input_sha1.hexdigest()[..7].as_bytes()
}
This is where my Rust gets a little hazy. Should I cast both things to bytes here? I don’t know, please feel free to PR against this post if there’s a suggestion!
Now we have everything we need and just need to write the logic combining our compare and display functiongs for showing the answer (in case of an incorrect answer) or just exiting:
match compare(input, fdx) {
true => {},
false => display(fdx)
};
Look on GitHub to see the whole thing put together. I simply add a line to my ~/.zshrc to execute the binary every time a new shell boots up and there we have it, auto-revision! | {"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": 0.6002415418624878, "perplexity": 3006.9916966818128}, "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/1508187825812.89/warc/CC-MAIN-20171023073607-20171023093607-00189.warc.gz"} |
http://www.responsivesoftware.com/mdac.htm | For database access, Time Logger depends on components that are a part of the Windows 98SE, Windows 2000, Windows XP, Windows Vista and Windows 2003 Server operating systems. These components are called "Microsoft Data Access Components," or "MDAC."
You may need to download and install these MDAC files yourself (they are free) if:
• You have Windows NT, Windows 95, or an earlier version of Windows 98, or
• The MDAC files on your system have been damaged, or
• Different Time Logger users have different versions of MDAC on their individual systems.
If you've already got the most recent MDAC files, you may want to check them to see if any are damaged, missing, or incorrect. You can do this with the MDAC Component Checker from Microsoft.
PLEASE NOTE: The MDAC Component Checker has often provided false positives for our customers. It is capable of correctly informing you that there is a problem. However, sometimes it reports that there is no problem, yet when our customers force the re-install of the MDAC it fixes their system.
# Installing (or Reinstalling) MDAC Files for Windows XP with SP2
NOTE: If you are using Windows XP with SP1 (Service Pack 1) then installing Service Pack 2 will update both the MDAC and Jet 4.0 files.
If you already have Windows XP with SP2 (Service Pack 2) installed, you can follow these directions to re-install the MDAC file.
### Background
Windows XP with Service Pack 2 contains MDAC version 2.81, which is currently not available for download at the Microsoft Web site as a standalone installation. If you try to install MDAC 2.8, which is the latest available standalone download of MDAC, you will receive a message that you already have a newer version of MDAC installed. Therefore, under Windows XP SP2, you must manually repair MDAC 2.81 as outlined below.
### How to Repair MDAC for Windows XP with SP2
1. In Windows Explorer, open the c:\Windows\Inf folder.
NOTE: If you cannot see the c:\Windows\Inf folder, please follow these steps:
a. Click START, click My Computer, and then click Folder Options on the Tools menu. b. Click the View tab. c. Under Advanced settings, click Show hidden files and folders. d. Click to clear the Hide extensions for known file types check box. e. Click Apply, and then click OK.
2. In the c:\Windows\Inf folder, right-click the Mdac.inf file, and then click Install.
3. When you are prompted to insert the Windows XP SP2 CD, use one of the following methods:
I. If you have a Windows XP SP2 CD: a. Insert the Windows XP Service Pack 2 CD in the CD or DVD drive. Note If a "Welcome to Microsoft Windows XP" message appears, click Exit. b. Click Browse. c. In the File name box, type CD drive letter:\i386. For example, if the Windows XP Service Pack 2 CD is in drive D, replace CD drive letter with "D" and type D:\i386 . d. Click Open.
II. If you do not have a Windows XP SP2 CD: NOTE: See "HOW TO SEARCH FOR FILES" below if you have trouble locating one of these files. a. In the File name box, type %systemroot%\windows\servicepackfiles\i386, and then click Open. NOTE: %systemroot% is the Drive letter and Path to where windows is installed. Typically, this is "C:\". Thus, the above would be: C:\windows\servicepackfiles\i386 b. When prompted for adcjavas.inc, point to C:\Windows\servicepackfiles\i386 NOTE: If you cannot find this folder put the Windows CD into your CD drive and browse for that file. c. When prompted for the file handler.reg, either point to C:\Program Files\Common Files\System\msadc, or put the Windows XP CD in your CD-ROM drive. d. When prompted for MDACRdMe.htm, point to C:\Program Files\Common Files\System\Ado. NOTE: If this file is not present rename the file MDACReadme.htm to MDACRdMe.htm. e. When prompted for oledbjvs.inc, point to C:\Program Files\Common Files\System\Ole DB. f. When prompted for mssoap1.dll, point to C:\Program Files\Common Files\MSSoap\Binaries. g. When prompted for mssoapr.dll, point to C:\Program Files\Common Files\MSSoap\Binaries NOTE: If this file is not present in that folder, browse to the subfolders below and see if it is there.
4. You may also be prompted for the original Windows XP CD that was used to install the operating system.
a. Insert the Windows XP Service Pack 2 CD in the CD or DVD drive. NOTE: If a "Welcome to Microsoft Windows XP" message appears, click Exit. b. Click Browse. c. In the File name box, type CD drive letter:\i386. For example, if the Windows XP Service Pack 2 CD is in drive D, replace CD drive letter with "D" and type D:\i386 . d. Click Open.
5. After installing MDAC above, attempt to install (or re-install) the Jet 4.0 files. Please read the note in 5.b below first. You will need to read the article below and refer to the directions for your version of Windows.
a. Click here to download the "Jet 4.0" Component Installer (Version 4.0). b. NOTE: With Windows XP SP2, if you have the latest security patches installed and are completely up to date with the Windows XP SP2 security bulletin updates, you will not be able to download and re-install the Jet 4.0 files because the latest updates should already be installed on your computer.
HOW TO SEARCH FOR FILES: In the case you cannot find any of the above files in the folders that are specified, you can select START then Search then For Files or Folders and then click "All Files and Folders" and enter the file name under "All or part of the file name:" and for the "Look in" field, specify your primary hard drive (usually C:). Once you locate one of the files, you will need to use the Browse option to point to (or navigate) to the folder where that file is stored.
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http://mathhelpforum.com/advanced-math-topics/213103-another-vector-qn-print.html | Another vector qn
• February 14th 2013, 05:50 AM
Tutu
Another vector qn
I found one more question, sorry for this!
Find the points on the line with parametric equations x=2-t, y=3+2t and z=1+t which are 5sqrt(3) units from the point (1,0,-2)
I found the line from the line parametric equations x=2-t, y=3+2t and z=1+t and the point (1,0,-2) thinking that it will equal to 5aqrt(3) but it was not so my whole concept is wrong. What are the steps here?
Thank you so so so much again!
• February 14th 2013, 09:02 AM
Plato
Re: Another vector qn
Quote:
Originally Posted by Tutu
Find the points on the line with parametric equations x=2-t, y=3+2t and z=1+t which are 5sqrt(3) units from the point (1,0,-2)
Solve: $[(2-t)-1]^2+[3+2t]^2+[(1+t)+2]^2=75$. | {"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": 0.7969395518302917, "perplexity": 3307.7576353732147}, "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-2016-36/segments/1471982292734.19/warc/CC-MAIN-20160823195812-00119-ip-10-153-172-175.ec2.internal.warc.gz"} |
http://mathoverflow.net/questions/143569/first-occurrence-of-by-the-usual-compactness-argument | # First occurrence of “by the usual compactness argument”?
In his blog, Jeff Shallit asks, what was the first occurrence of the exact phrase, "by the usual compactness arguments," in the mathematical literature?
He reports that the earliest appearance he has found was in a paper from 1953: it's on page 400 of John W. Green, Pacific Journal of Mathematics 3 (2) 393-402.
I found another example from that same year, on page 918 of F. A. Valentine, Minimal sets of visibility, Proc Amer Math Soc 4, 917-921.
So, is this year the 60th anniversary of the first appearance of that phrase?
If there was an earlier occurrence of the equivalent phrase in a language other than English, that, too, would be of interest.
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Why do you insist on exactness of this type of a phrase? – Włodzimierz Holsztyński Sep 30 '13 at 7:27
Question probably better directed to Jeff. I suppose anything showing that compactness arguments had become so standard that authors felt they could get away without giving any details would be of interest. – Gerry Myerson Sep 30 '13 at 9:36
There is a paper, written in German, called Ueber Räume mit verschwindender erster Brouwerscher Zahl. by Urysohn and Alexandroff from 1928. (Notice that Urysohn drowned while swimming with Alexandroff in 1924)
The following quote is from page 810 (emphasis added):
Der Beweis dieser Tatsache ist wörtlich derselbe wie im Falle, wo $R$ der $R^n$ ist: es genügt zu zeigen, dass die erwähnte Trennungseigenschaft im Brouwerschen Sinne induktiv ist (was aus der Kompaktheit von $R$ in der üblichen Weise folgt), und dann den Phragmén-Brouwerschen Satz anzuwenden.
And here is my translation of that quote:
The proof of this fact is literally the same as in the case, where $R$ is $R^n$: it is sufficient to show that the mentioned separation property is inductive in the sense of Brouwer (which follows from the compactness of $R$ in the usual fashion), and then apply the Phragmén-Brouwer Theorem.
I suspect, that as soon as there was a good notion of compactness, people used it in a routine way as an standard argument.
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Lets add that it was Alexandrov and Urysohn who introduced (invented) the general modern notion of compactness (called by them bi-compactness). – Włodzimierz Holsztyński Sep 30 '13 at 18:10
Yes, I guess this was sometimes around 1923/24, in some French and German papers. – Moritz Firsching Sep 30 '13 at 20:03
As far as English, there are earlier results for the phrasing standard compactness argument(s).
In particular, a few papers are linked to from 1947: see here on Google Scholar.
The earliest of the three is:
Ambrose, W. (1947). Direct sum theorem for Haar measures. Transactions of the American Mathematical Society, 61(1), 122-127.
Specifically: Lemma 4 (p. 125) contains the phrasing "by standard compactness arguments"; see below.
Historical remark: There is a French paper entitled, "History of the Concept of Compactness" (Pier, J. P. (1980). Historique de la notion de compacité. Historia mathematica, 7(4), 425-443. http://www.sciencedirect.com/science/article/pii/0315086080900063), and among the important names in its development is Alexandroff (cited in the other response here). The reference list includes two of his papers (including another one with Urysohn) from 1924, as well as a book (with Hopf) from 1935. The paper lists Fréchet as the first to define a compact set, so I wouldn't be surprised if there are earlier uses of equivalent phrasing in French that predate either of the responses thus far.
- | {"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": 0.8577992916107178, "perplexity": 1714.876329386636}, "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-2014-42/segments/1414119645920.6/warc/CC-MAIN-20141024030045-00282-ip-10-16-133-185.ec2.internal.warc.gz"} |
https://gis.stackexchange.com/questions/113095/how-to-iterate-through-features-in-a-shapefile-using-r/114481 | # How to iterate through features in a shapefile using R?
I am interested in iterating through a point shapefile to perform tasks on a point by point basis using R. In Python, this can be accomplished using the following workflow:
import arcpy
shp = r'C:\path\to\shapefile.shp'
with arcpy.da.SearchCursor(shp, ["Field", "SHAPE@"]) as cursor:
for row in cursor:
print row[0]
# Perform some action with row[1] (i.e. the point geometry)
How can I iterate through a point shapefile to access individual point geometry using R?
• Do you have an example of shapefile? – user32309 Sep 9 '14 at 7:48
• @Pascal Any point shapefile would do. – Aaron Sep 9 '14 at 12:58
To subset or operate on an individual object all you need is the "row" index, which corresponds to the slots. In this way it is independent of feature class type (i.e., point, polygon, pixel).
# To iterate through the feature class
for(i in 1:nrow(shp)) { p <- shp[i,] }
Not sure whether it is what you are looking for (it depends on the action you want to perform). For example, let's use a shapefile of populated places.
library(rgdal)
shp <- "C:\path\to\shapefile"
OGR data source with driver: ESRI Shapefile
Source: "C:\path\to\shapefile", layer: "ne_10m_populated_places_simple"
with 7322 features and 36 fields
Feature type: wkbPoint with 2 dimensions
class(pts)
[1] "SpatialPointsDataFrame"
attr(,"package")
[1] "sp"
names(pts)
[1] "scalerank" "natscale" "labelrank" "featurecla" "name" "namepar" "namealt" "diffascii" "nameascii"
[19] "adm1name" "iso_a2" "note" "latitude" "longitude" "changed" "namediff" "diffnote" "pop_max"
[28] "pop_min" "pop_other" "rank_max" "rank_min" "geonameid" "meganame" "ls_name" "ls_match" "checkme"
To access the name of the places:
pts$name head(pts$name)
[1] Colonia del Sacramento Trinidad Fray Bentos Canelones Florida
[6] Bassar
7069 Levels: 25 de Mayo 28 de Noviembre Aalborg Aarau Aba Abadan Abadla Abaetetuba Abai Abakan Abancay Abau Abaza ... Zyryanovsk
If you want the associated coordinates:
pts["name"]
pts[1:5,"name"]
coordinates name
1 (-57.84, -34.48) Colonia del Sacramento | {"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": 0.3774694800376892, "perplexity": 25085.20566741142}, "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-2021-17/segments/1618038084765.46/warc/CC-MAIN-20210415095505-20210415125505-00333.warc.gz"} |
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# Embedded Help!
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9 replies to this topic
### #1mKatz Members - Reputation: 738
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Posted 17 August 2012 - 11:19 AM
I'm creating a class for a later program called EthicalCompetition. I'm stuck on an error code and don't truely understand the meaning of it, if anyone could help me out I would be very appreciated.
#include "stdafx.h"
#include <iostream>
using namespace std;
class EthicalCompetition
{
private:
class Connection;
public:
void HardWork();
};
class EthicalCompetition::Connection{
protected:
friend class EthicalCompetition;
void Connect();
Connection() {}
~Connection() {}
};
void EthicalCompetition::HardWork()
{
Connection c;
c.Connect();
cout << "Connected" << endl;
}
void EthicalCompetition::Connection::Connection()
{
cout << "Connecting..." << endl;
}
int main(int argc, char *argv[])
{
//EthicalCompetition::Connection myconnect;
EthicalCompetition comp;
comp.HardWork();
system("pause");
return 0;
}
error code
1>------ Build started: Project: Tracing, Configuration: Debug Win32 ------
1> Tracing.cpp
1>c:\users\jonbecher\documents\visual studio 2012\projects racing racing racing.cpp(26): error C2533: 'EthicalCompetition::Connection::{ctor}' : constructors not allowed a return type
1>c:\users\jonbecher\documents\visual studio 2012\projects racing racing racing.cpp(26): error C2084: function 'EthicalCompetition::Connection::Connection(void)' already has a body
1> c:\users\jonbecher\documents\visual studio 2012\projects racing racing racing.cpp(16) : see previous definition of '{ctor}'
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
Edited by JonBMN, 17 August 2012 - 11:20 AM.
### #2ReaperSMS Members - Reputation: 1100
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Posted 17 August 2012 - 11:27 AM
As the error messages mention, you're trying to redefine EthicalCompetition::Connection::Connection(). You define it as an empty inline method in the class definition for it above.
Perhaps you meant for the second definition to be EthicalCompetition::Connection::Connect()?
If the horrible spacing isn't the board's fault, I highly suggest modern inventions like indentation. It's 2012, you can afford a tab or three in a file.
### #3mKatz Members - Reputation: 738
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Posted 17 August 2012 - 01:50 PM
As the error messages mention, you're trying to redefine EthicalCompetition::Connection::Connection(). You define it as an empty inline method in the class definition for it above.
Perhaps you meant for the second definition to be EthicalCompetition::Connection::Connect()?
If the horrible spacing isn't the board's fault, I highly suggest modern inventions like indentation. It's 2012, you can afford a tab or three in a file.
Could you explain a little further please.
And yes it is the board's fault, I suggest before being condescending you just help out and not assume. Thank you.
### #4ReaperSMS Members - Reputation: 1100
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Posted 17 August 2012 - 02:20 PM
This is the relevant part of the code:
class EthicalCompetition::Connection{
protected:
friend class EthicalCompetition;
void Connect();
Connection() {} // this line defines EthicalCompetition::Connection::Connection as an empty default constructor
~Connection() {}
};
void EthicalCompetition::Connection::Connection() // this line attempts to redefine it as an invalid constructor
{
cout << "Connecting..." << endl;
}
Constructors defined outside of classes do not have return types specified, this includes void. Your code snippet also neglected to define EthicalCompetition::Connection::Connect(), which makes me think that's what you meant to type for the function that prints "Connecting...".
### #5DoctorGlow Members - Reputation: 1019
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Posted 17 August 2012 - 02:30 PM
And yes it is the board's fault, I suggest before being condescending you just help out and not assume. Thank you.
Then why code snippet from ReaperSMS has spaces and it looks readable?
### #6mKatz Members - Reputation: 738
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Posted 17 August 2012 - 02:50 PM
And yes it is the board's fault, I suggest before being condescending you just help out and not assume. Thank you.
Then why code snippet from ReaperSMS has spaces and it looks readable?
It's how he put it into the code snippet program; mine came straight from the IDE and I put the [ code ] around it myself. Please do not come onto the forum to argue, this is a place for help. He gave his opinion I gave mine. Neither of us needs you to intervene on this matter, and since your neither helping nor posting for a good reason. I'd ask you to please not post on my topic trying to mediate.
Thank you.
### #7mKatz Members - Reputation: 738
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Posted 17 August 2012 - 02:51 PM
This is the relevant part of the code:
class EthicalCompetition::Connection{
protected:
friend class EthicalCompetition;
void Connect();
Connection() {} // this line defines EthicalCompetition::Connection::Connection as an empty default constructor
~Connection() {}
};
void EthicalCompetition::Connection::Connection() // this line attempts to redefine it as an invalid constructor
{
cout << "Connecting..." << endl;
}
Constructors defined outside of classes do not have return types specified, this includes void. Your code snippet also neglected to define EthicalCompetition::Connection::Connect(), which makes me think that's what you meant to type for the function that prints "Connecting...".
I appreciate this greatly thank you!
### #8DoctorGlow Members - Reputation: 1019
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Posted 17 August 2012 - 02:54 PM
And yes it is the board's fault, I suggest before being condescending you just help out and not assume. Thank you.
Then why code snippet from ReaperSMS has spaces and it looks readable?
It's how he put it into the code snippet program; mine came straight from the IDE and I put the [ code ] around it myself. Please do not come onto the forum to argue, this is a place for help. He gave his opinion I gave mine. Neither of us needs you to intervene on this matter, and since your neither helping nor posting for a good reason. I'd ask you to please not post on my topic trying to mediate.
Thank you.
I was curious as to reason of difference between those snippets of the code. There is no reason to get angry about it.
### #9LordSputnik Members - Reputation: 132
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Posted 21 August 2012 - 03:09 PM
One used spaces, one used tabs:
[source lang="cpp"] This is a tabbed line. And another. This line has two spaces. And this line.[/source]
The spaces appear to get removed from the code when it's pasted, the tabs don't.
### #10rip-off Moderators - Reputation: 9788
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Posted 21 August 2012 - 03:56 PM
Disabling the fancy editor makes everything behave more reasonably, I have found (the little light switch in the top left). If anyone else has any editing hints, maybe let people know via private message however, to help keep us on topic.
That said, please don't be so defensive JonBMN, learning how best to prepare your code for the forums is important, it benefits everyone here. We find it easier to read code, and you get more and better responses that are also easy for you to read.
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PARTNERS | {"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": 0.1581621617078781, "perplexity": 3725.5049312298042}, "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/1438042990114.79/warc/CC-MAIN-20150728002310-00119-ip-10-236-191-2.ec2.internal.warc.gz"} |
https://www.physicsforums.com/threads/divergence-theorem.515316/ | # Divergence theorem
1. Jul 19, 2011
### athrun200
1. The problem statement, all variables and given/known data
2. Relevant equations
3. The attempt at a solution
I can get the answer after applying divergence theorem to have a volume integral.
It seems the 4 points given can't form a surface.
#### Attached Files:
• ###### 未命名 -1.jpg
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2. Jul 19, 2011
### Office_Shredder
Staff Emeritus
Don't confuse a surface with a plane. The surface of the cube is all six of its sides
3. Jul 19, 2011
### LCKurtz
Those four points don't form a cube either. The problem doesn't imply that they do either. But the problem says a cube includes those four vertices, and that is enough to determine the cube. Presumably you knew that otherwise how did you apply the divergence theorem? It's the surface of that cube you need to use.
4. Jul 19, 2011
### HallsofIvy
Staff Emeritus
I don't believe that Office Shredder meant to imply that it was a cube- he was only giving that as an example. His point was what you said- that every solid has a surface (not necessarily smooth) as boundary. Here, the surface is made of four planes.
5. Jul 19, 2011
### LCKurtz
If you are addressing that to me, I was neither quoting nor replying to Office Shredder. The original post clearly refers to the cube containing those four vertices, not a tetrahedron, and the OP was apparently missing that when trying to figure out the surface.
6. Jul 19, 2011
### hunt_mat
Well, you know that a cube has 6 sides that are the same, so from the the information given you should be able to construct the cube from that.
Similar Discussions: Divergence theorem | {"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": 0.8707836270332336, "perplexity": 1347.6409367106276}, "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-2017-39/segments/1505818691830.33/warc/CC-MAIN-20170925130433-20170925150433-00405.warc.gz"} |
http://mathoverflow.net/questions/37965/completeness-and-cocompleteness-of-the-kleisli-category?answertab=votes | Completeness and cocompleteness of the Kleisli category
If (T,η,μ) is a monad over a category C, which is complete and cocomplete, then what about the Kleisli category? And also, if C is cartesian closed, what about the Kleisli one?
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In general, the Kleisli category will be neither complete nor cocomplete nor cartesian closed, even if $C$ is.
You can think of the Kleisli category as the full subcategory of algebras whose objects are the free algebras. So take for example $T$ to be the monad coming from the free-forgetful adjunction between abelian groups and sets. In order for $\mathbb{Z} \times -: FreeAb \to FreeAb$ to have a right adjoint (as required by cartesian closure), it would have to preserve all colimits, for example coproducts. But $\mathbb{Z} \times (\mathbb{Z} \oplus \mathbb{Z})$ is not isomorphic to $(\mathbb{Z} \times \mathbb{Z}) \oplus (\mathbb{Z} \times \mathbb{Z})$.
Now let's tackle completeness. We can use the same example; the basic idea is that free abelian groups are not closed under (infinite) products. (In fact, a famous but nontrivial result, due to Kurosh I believe, is that the countably infinite power of $\mathbb{Z}$ is not free abelian.) But to apply this idea, one should first check that any limit in $Kl(T)$ really is constructed just as it would be in $Alg(T)$ or in $C$. That's not hard: first note that the underlying functor $U: Kl(T) \to C$ is representable (in fact, $U \cong \hom(F(1), -)$), so $U$ preserves any limits that exist in $Kl(T)$. Also, $U$ reflects isomorphisms (i.e., if $U(g)$ is an isomorphism in $C$, then $g$ is an isomorphism in $Kl(T)$). It follows that $U$ both preserves and reflects limits, and so any limit in $Kl(T)$ is constructed as it would be in $Alg(T)$ or $C$ (here, $Set$).
Finally, cocompleteness. This time I don't think the example above works quite as easily, but one example that does work is to consider the Kleisli category for the free-forgetful adjunction between $\mathbb{Z}_6$-modules and sets. I claim that the coequalizer of the pair $id, \mu_3: \mathbb{Z}_6 \to \mathbb{Z}_6$ ($\mu_3$ is multiplication by 3) does not exist in the category of free $\mathbb{Z}_6$-modules. I chose this particular coequalizer because it is an example of "splitting an idempotent"; here the idempotent is $\mu_3$. The virtue of splittings of idempotents is that they are preserved by any functor whatsoever, and reflected by any functor that reflects isomorphisms. Given this fact, it follows that splittings of idempotents in $Kl(T)$, if they exist, are constructed just as they would be in $Alg(T)$ or in $C$. But the idempotent splitting of this pair of maps in $\mathbb{Z}_6$-Mod is $\mathbb{Z}_2$, which is not free. It follows that the coequalizer doesn't exist in the Kleisli category.
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Thank you. But I am not clear that when and where the limit or colimit of the Kleisli category exists? Another question, if the base category is not cartesian closed, is it possible that the Elienberg-Moore category cartesian closed? – Jenny Sep 9 '10 at 7:29
It's hard to give reasonable general answers. I can say that if $C$ has coproducts, so does $Kl(T)$. Depending on $C$ and the monad $T$, it may be that $Kl(T)$ is complete and cocomplete; for example if $C$ is bicomplete and every $T$-algebra is free. This happens e.g. when $T$ is an idempotent monad; details at ncatlab.org/nlab/show/completion. But usually it comes down to individual cases and asking questions like: are products of free objects free? Are subobjects of free objects free? If you do have a specific example, maybe we can discuss that. Ans. to 2nd question next comment. – Todd Trimble Sep 9 '10 at 8:26
There are many weird examples where this can happen. A silly example is where you take a non-distributive lattice $L$ and define $T: L \to L$ to take the bottom element 0 to 0, and every other element to the top element 1. The Eilenberg-Moore category is then the two-element lattice which is cartesian closed. Slightly less silly: take $C = Top/X$, which is generally not cartesian closed, and $T$ to take a map $f: Y \to X$ to its image $im(f) \hookrightarrow X$. The EM category is then the lattice of subspaces of $X$ which is cartesian closed. But why do you ask? – Todd Trimble Sep 9 '10 at 8:47
Take the Probabilistic Powerdomain of Evaluations as example, the base category is Dcpo, directed complete posets with Scott continuous functions, does the finite product of the Kleisli category of this monad exist? – Jenny Sep 9 '10 at 13:48
I don't know, Jenny. It might be worthwhile posting this as a separate question at MO (preferably with a link to a suitable document with relevant definitions). Or, perhaps you know an expert in domain theory you can ask directly? Good luck! – Todd Trimble Sep 9 '10 at 20:47 | {"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": 0.9327387809753418, "perplexity": 249.27501637263344}, "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/1427131298755.8/warc/CC-MAIN-20150323172138-00006-ip-10-168-14-71.ec2.internal.warc.gz"} |
https://www.physicsforums.com/threads/creation-of-energy.10607/ | # Creation of Energy
1. Dec 9, 2003
Hello,
I am new to this forum so i'm not even sure if my question belongs here. Anyway, i am aware that the sun has the natural ability to create new kinds ot atoms throught it's gravitational force but can it or anything in this universe create Energy?
2. Dec 9, 2003
### pallidin
My general thoughts on this is that energy can cannot be created from nothing. But, energy can be converted from one form to another, and energy can be converted from mass. Yet, the energy or mass being manipulated must already exist so in reality, no matter what one does, one is merely changing what already exists.
The "new" creation of energy was likely done only once, during the creation of the universe.
3. Dec 9, 2003
### LURCH
Welcome to the Forums, Michael!
This question is going to get into definitions a little bit. You see, the Sun doesn't actually "create" new kinds of atoms, not by the traditional use of that term, at least. It assembles them by taking already existing atoms and putting them together in new configurations. But the law of conservation, which states that energy can neither be created nor annihilated, uses the word "created" in the more literal sense; to bring something into existance ex nihilo(out of nothing).
In this sense, the answer to your question would be: No, neither stars nor any other known phenominon can create energy. And, since matter is made of energy, it cannot be created or distroyed, either. Matter and energy can only be rearanged; converted from one form to another, assemblerd, dissassembled, etc.
4. Dec 9, 2003
I always thought that but tell me if you can that if enegy cannot be created then how did we come to be? (In nice voice)
I would expect that energy would have to be created somehow - leading back to the big bang no doubt.
5. Dec 10, 2003
### turin
So, what about a random quantum fluxuation? If some system, say a HO, is not in an energy eigenstate (you measure the position , and the position operator does not commute with the Hamiltonian), how can one even talk about conservation of energy?
6. Dec 10, 2003
### Staff: Mentor
It is true that in general classical physics breaks down on a quantum scale.
Thats complicated, but essentially, when the universe was created, it had all the energy in it that it has now. It doesn't violate conservation because there is no "before" state with which to compare energy levels. Thats part of the Big Bang theory.
7. Dec 11, 2003
Energy had to come from somewhere even if it were from Hyper Space or an Alterate Reallity it still must have some from somewhere (STill in nice voice)
8. Dec 11, 2003
### turin
Why? Conservation of energy will never be anything more than a model, albeit I must admit that I put more faith in that model than in almost any other.
9. Dec 11, 2003
### chroot
Staff Emeritus
One physicist actually went so far as to describe questions like as existing in something he called "Bubble Land." Questions in Bubble Land simply have no answers right now. They are the questions at which physics and philosophy meet.
We don't really know the answer to your question: where did the energy for our universe come from? It is entirely possible that we will never know the answer to this question, because we cannot escape our own universe to see if there is actually something "outside" it. It is possible that our universe is just a quantum fluctuation, and all its energy has been borrowed (temporarily) from the vacuum, in the same way that virtual photons produce and disappear constantly in a laboratory vacuum.
Don't be dissuaded in your interest in science because we can't yet answer your question -- there are lots of fascinating things we can say about your question, but we may never be able to assign it an answer.
- Warren
10. Dec 14, 2003
### Piecemaster
gamma rays passing close to an atomic nucleus can create an electron positron pair. It might therefore follow that energy was not just created from nothing but there becomes from nothing a positive and an equal but opposite negative. If a positron encounteres an electron they anihilate, or become nothing again giving off a photon.
11. Dec 15, 2003
### turin
I wouldn't say that this demonstrates something coming from nothing, at least not without mentioning that the gamma ray ceases to exist, and so, at the same time, something became nothing.
Where did the photon come from?
12. Dec 15, 2003
### jcsd
You have to ammend the conservation so that $\Delta E\Delta t \geq \frac{\hbar}{2}$ is remembered. Superposed states aren't a problem as the wavefunction shouldn't be given direct physical signifcance in the conventional interpreation of quantyum measuremnt.
13. Dec 15, 2003
### turin
Are you suggesting that, even in the context of QM, since $\Delta E\Delta t \geq \frac{\hbar}{2}$, then the amount of energy that should be accounted for couldn't have come from a quantum fluxuation, because this energy has been around a lot longer than the $\Delta t$ that this relation allows? I have never been comfortable with this relation. Can you explain where it came from?
That is highly subjective. What do you think the conventional interpretation of QM is?
14. Dec 16, 2003
### jcsd
You just have to take into account that energy obeys an uncertainty relationship and it's only conserved within the limits allowed by this uncertanity relationship. For example you can think of quantum mechanical tunelling as a particle borrowing energy within the limits of uncertainty, but if you were to actually perform a measuremtn on a particle it would never have an energy that violates the conservation of energy. Simlairly if you were to perform a measuremnt on a superposed state your results would never violate the conservation of energy.
The convential interpretaion is the Copenhagen interpretaion suitably adjusted to allow new concepts in quantum measurment such as decoherence.
15. Dec 16, 2003
### turin
I guess I just don't understand that uncertainty relationship. Can you explain it to us?
Another thing I just realized. This so called uncertainty relationship seems to suggest that there is no problem with an infinite uncertainty in energy. So, I think that just about puts us where we are now. How certain are we of the amount of energy there is in the universe? I am personally just about infinitely uncertain. But according to the uncertainty relationship provided, that's OK. Because I've lived for some number of years, and my uncertainty of the total energy of the universe is huge, so these two factors are in agreement with this uncertainty relationship. Am I misinterpretting?
I do not at all see what this has to do with energy conservation.
Why would I think of it that way? The QM wavefunction extends to regions of space where classical particles have zero probablity to exist. I don't understand "borrowing energy within the limits of uncertainty." Can you elaborate this borrowing process?
I agree, but I didn't mean that there would be a violation of energy conseration. I meant that energy conservation just doesn't make sense to me in the case of a superposition of energy eigenstates.
For simplicity, let's say that a system is in a superposition of 2 energy eigenstates, ψa and ψb, with nondegenerate eigenvalues, Ea and Eb, respectively. Lets say that the superposition is:
ψ = (ψa + ψb)/√2.
If I measure the energies of some number of these identical systems, then half of the time I will find that the energy is Ea and half of the time I will find that the energy is Eb. It's not that this amount of energy was conserved or something. We can't really say anything about the particular amount of energy of the system until we make the measurement. So, that's why I'm saying it doesn't really make sense to me to speak of energy conservation in this case.
It is my experience, as well, that the Copenhagen interpretation is the conventional one. I don't know anything about decoherence (I don't even know what it means), though, so I guess that disqualifies me from much of the discussion.
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http://sobertimes.com/roberta-mccain-ssgbbyk/d503b4-into-function-is-also-called | [14][31] That is, f is bijective if, for any ∈ ) f Y This is the way that functions on manifolds are defined. and This process is the method that is generally used for defining the logarithm, the exponential and the trigonometric functions of a complex number. = y y ∈ {\displaystyle 0,{\sqrt {3}},{\text{ or }}-{\sqrt {3}}} ∈ by the formula ( 4 n . {\displaystyle y\in Y} Y − × {\displaystyle g\colon Y\to X} Also, the statement "f maps X onto Y" differs from "f maps X into B", in that the former implies that f is surjective, while the latter makes no assertion about the nature of f the mapping. − {\displaystyle g\circ f=\operatorname {id} _{X},} ) , ) ∑ − In usual mathematics, one avoids this kind of problem by specifying a domain, which means that one has many singleton functions. t. e. In mathematics, an injective function (also known as injection, or one-to-one function) is a function that maps distinct elements of its domain to distinct elements of its codomain. f An extension of a function f is a function g such that f is a restriction of g. A typical use of this concept is the process of analytic continuation, that allows extending functions whose domain is a small part of the complex plane to functions whose domain is almost the whole complex plane. {\displaystyle {\sqrt {x_{0}}},} ( Problem 7. Show that f is an surjective function from A into B. f , i g {\displaystyle x^{3}-3x-y=0} = or is a function, A and B are subsets of X, and C and D are subsets of Y, then one has the following properties: The preimage by f of an element y of the codomain is sometimes called, in some contexts, the fiber of y under f. If a function f has an inverse (see below), this inverse is denoted ) y Other approaches of notating functions, detailed below, avoid this problem but are less commonly used. f(a) = b, then f is an on-to function. . Let f: XâY be a function. {\displaystyle f(X)} For example, if f is the function from the integers to themselves that maps every integer to 0, then However, as the coefficients of a series are quite arbitrary, a function that is the sum of a convergent series is generally defined otherwise, and the sequence of the coefficients is the result of some computation based on another definition. . However, when establishing foundations of mathematics, one may have to use functions whose domain, codomain or both are not specified, and some authors, often logicians, give precise definition for these weakly specified functions.[32]. ↦ 1 but, in more complicated examples, this is impossible. = 0 X can be defined by the formula , For example, when extending the domain of the square root function, along a path of complex numbers with positive imaginary parts, one gets i for the square root of –1; while, when extending through complex numbers with negative imaginary parts, one gets –i. , 1 2 ∘ x , f 1 Most kinds of typed lambda calculi can define fewer functions than untyped lambda calculus. if x In computer programming, a function is, in general, a piece of a computer program, which implements the abstract concept of function. S When only a copy of an argument is passed to a function, it is said to be passed by _____. t However, when extending the domain through two different paths, one often gets different values. A simple example of a function composition. f f → i f Y R x For example, the position of a planet is a function of time. That is, it is a program unit that produces an output for each input. 2 { 1 such that the restriction of f to E is a bijection from E to F, and has thus an inverse. {\displaystyle -d/c,} ) A binary relation is functional (also called right-unique) if, A binary relation is serial (also called left-total) if. y + ∈ 1 → The simplest example is probably the exponential function, which can be defined as the unique function that is equal to its derivative and takes the value 1 for x = 0. defines a function and , Y f R n i [10][11][12][13] However, range is sometimes used as a synonym of codomain,[13][14] generally in old textbooks. 3 are equal to the set , to the element ( ∘ Values inside the function before change: [10, 20, 30] Values inside the function after change: [10, 20, 50] Values outside the function: [10, 20, 50] There is one more example where argument is being passed by reference and the reference is being overwritten inside the called function. f {\displaystyle y\in Y} 2 2 Some authors[25] reserve the word mapping for the case where the structure of the codomain belongs explicitly to the definition of the function. : The implicit function theorem provides mild differentiability conditions for existence and uniqueness of an implicit function in the neighborhood of a point. − Y For example, Von Neumann–Bernays–Gödel set theory, is an extension of the set theory in which the collection of all sets is a class. 1 [10] If A is any subset of X, then the image of A under f, denoted f(A), is the subset of the codomain Y consisting of all images of elements of A,[10] that is, The image of f is the image of the whole domain, that is, f(X). such that for each pair The set of these points is called the graph of the function; it is a popular means of illustrating the function. under the square function is the set g for x. ( 0 If the f , [ X x { 3 An antiderivative of a continuous real function is a real function that is differentiable in any open interval in which the original function is continuous. x there is some this defines a function are equal. X X ) f R 5 : When the elements of the codomain of a function are vectors, the function is said to be a vector-valued function. Mapping (when a function is represented using Venn-diagrams then it is called mapping), defined between sets X and Y such that Y has at least one element 'y' which is not the f-image of X are called into mappings. , Two functions f and g are equal, if their domain and codomain sets are the same and their output values agree on the whole domain. Whichever definition of map is used, related terms like domain, codomain, injective, continuous have the same meaning as for a function. using the arrow notation for elements. (In old texts, such a domain was called the domain of definition of the function.). X {\displaystyle y^{5}+x+1=0} ↦ When a function is defined this way, the determination of its domain is sometimes difficult. The heading of the function is also called the ___ A. title B. calling sequence C. interface D. implementation E. Both B and C are correct {\displaystyle f(x)={\sqrt {1+x^{2}}}} ) , x = ( x More formally, f = g if f(x) = g(x) for all x ∈ X, where f:X → Y and g:X → Y. − d → x t {\displaystyle x\mapsto {\frac {1}{x}}} It is not required that x be unique; the function f may map one or more elements of X to the same element of Y. th coordinate of this tuple is the value of the domain such that can be represented by the familiar multiplication table. = is a bijection, and thus has an inverse function from : {\displaystyle \mathbb {R} ^{n}} An onto function is also called surjective function. The notation Thus, if for a given function f(x) there exists a function g(y) such that g(f(x)) = x and f(g(y)) = y, then g is called the inverse function of f and given the notation f â1, where by convention the variables are interchanged. may be factorized as the composition i ∘ s of a surjection followed by an injection, where s is the canonical surjection of X onto f(X) and i is the canonical injection of f(X) into Y. 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( x f That is, the function is both injective and surjective. {\displaystyle A=\{1,2,3\}} {\displaystyle f^{-1}(B)} In this example, (g ∘ f )(c) = #. t ( , y id The derivative of a real differentiable function is a real function. Activity: CodeLens 6.6.1 (sumofsquares) Even though this is a pretty simple idea, in practice this example illustrates many very important Python concepts, including local and global variables along with parameter passing. Roughly speaking, they have been introduced in the theory under the name of type in typed lambda calculus. For example, if a function is supposed to calculate the area of a square, the result would be the area of a square. {\displaystyle f(x,y)=xy} , : X ( It is customarily denoted by letters such as f, g and h.[1], If the function is called f, this relation is denoted by y = f (x) (which reads "f of x"), where the element x is the argument or input of the function, and y is the value of the function, the output, or the image of x by f.[2] The symbol that is used for representing the input is the variable of the function (e.g., f is a function of the variable x).[3]. X , C ∫ f Into Function : Function f from set A to set B is Into function if at least set B has a element which is not connected with any of the element of set A. 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https://maze-rl.readthedocs.io/en/latest/concepts_and_structure/policy_and_agent.html | # Policies, Critics and Agents¶
Depending on the domain and task we are working on we rely on different trainers (algorithm classes) to appropriately address the problem at hand. This in turn implies different requirements for the respective models and contained policy and value estimators.
The figure below provides a conceptual overview of the model classes contained in Maze and relates them to compatible algorithm classes and trainers.
Note that all policy and critics are compatible with Structured Environments.
## Policies (Actors)¶
An agent holds one or more policies and acts (selects actions) according to these policies. Each policy consists of one ore more policy networks. This might be for example required in (1) multi-agent RL settings where each agents acts according to its distinct policy network or (2) when working with auto-regressive action spaces or multi-step environments.
In case of Policy Gradient Methods, such as the actor-critic learners A2C or PPO, we rely on a probabilistic policy defining a conditional action selection probability distribution $$\pi(a|s)$$ given the current State $$s$$.
In case of value-based methods, such as DQN, the Q-policy is defined via the state-action value function $$Q(s, a)$$ (e.g, by selecting the action with highest Q value: $$\mathrm{argmax}_a Q(s, a)$$).
## Value Functions (Critics)¶
Maze so far supports two different kinds of critics. A standard state critic represented via a scalar value function $$V(S)$$ and a state-action critic represented either via a scalar state-action value function $$Q(S, A)$$ or its vectorized equivalent $$Q(S)$$ predicting the state-action values for all actions at once.
Analogously to policies each critic holds one or more value networks depending on the current usage scenario we are in (auto-regressive, multi-step, multi-agent, …). The table below provides an overview of the different critics styles.
State Critic $$V(S)$$ TorchStepStateCritic Each sub-step or actor gets its individual state critic. TorchSharedStateCritic One state critic is shared across all sub-steps or actors. State-Action Critic $$Q(S, A)$$ TorchStepStateActionCritic Each sub-step or actor gets its individual state-action critic. TorchSharedStateActionCritic One state-action critic is shared across all sub-steps or actors.
## Actor-Critics¶
To conveniently work with algorithms such as A2C, PPO, IMPALA or SAC we provide a TorchActorCritic model to unifying the different policy and critic types into one model. | {"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": 0.3590630888938904, "perplexity": 2792.7365403102626}, "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/1634323585449.31/warc/CC-MAIN-20211021230549-20211022020549-00558.warc.gz"} |
http://math.stackexchange.com/questions/442326/math-olympiad-problem | A year is peculiar if the sum of the first two digits and the last two digits is equal to the middle two digits. For example, 1978. When was the last peculiar year and is there an algorithm to find any peculiar year?
How would I go about solving this problem? I am completely lost. Any ideas would help.
-
for i=0 to 2013; If ... then print ... – Lord Soth Jul 12 '13 at 20:45
@LordSoth are you suggesting to put leading zeros to those years with number of digits less than 4, since you've started from 0? – Kaster Jul 12 '13 at 20:52
@LordSoth: Starting in 1978 seems like a much better idea. Or just going backwards from 2013. – Chris Eagle Jul 12 '13 at 20:52
All four-digit peculiar years are: 1208, 1318, 1428, 1538, 1648, 1758, 1868, 1978, 2307, 2417, 2527, 2637, 2747, 2857, 2967, 3406, 3516, 3626, 3736, 3846, 3956, 4505, 4615, 4725, 4835, 4945, 5604, 5714, 5824, 5934, 6703, 6813, 6923, 7802, 7912, 8901. Do you notice a pattern? – dtldarek Jul 12 '13 at 20:59
Guys, I think all of you are missing one important thing – this is/was a math problem, not a 5-th grade programming problem, so it needs to be solved somehow analytically and somewhat intuitively. As a starter, if $\overline{abcd}$ your number, where $0 < a \le 9,\, 0 \le a,b,c \le 9$ and $a,b,c,d \in \mathbb N$, then the condition might be written as $$10a + b + 10c + d = 10b + c$$ So, one might try to solve it using divisibility or whatever. – Kaster Jul 12 '13 at 21:04
There is no peculiar year in the 21st century, since the middle two digits form a 1 digit number.
In the 20th century, any year is of the form $19xy$. Then the year is peculiar if and only if
$$19+xy=9x \Leftrightarrow 19+10x+y=90+x \Leftrightarrow 9x+y=71 \,.$$
Then since $0 \leq y \leq 9$ we get
$$9x \leq 71 \leq 9x+9 \Rightarrow 62 \leq 9x \leq 71 \Rightarrow x=7 \,.$$
Plugging $x=7$ in $9x+y=71$ we get that $y=8$.
Thus, the only peculiar year in 20's century is 1978.
If the question asks for the peculiar year before 1978, it must be in the 19th century or before:
Repeating:
In the 19th century, any year is of the form $18xy$. Then the year is peculiar if and only if
$$18+xy=8x \Leftrightarrow 18+10x+y=80+x \Leftrightarrow 9x+y=62 \,.$$
Then
$$9x \leq 62 \leq 9x+9 \Rightarrow 53 \leq 9x \leq 62 \Rightarrow x=6 \,.$$
Plugging $x=6$ in $9x+y=62$ we get that $y=8$.
Thus in the 19th century the only peculiar year is $1868$.
P.S. Any peculiar year of the form $1abc$ satisfies
$$10+a+10b+c=10a+b \Rightarrow 9a-9b-c=10$$
This implies that $c \equiv -1 \pmod{9}$ thus $c=8$ and then
$$a-b=2 \,.$$
From here you get easily all the peculiar years between $1000$ and $1999$.
P.P.S. If you are looking for all $4$ digits answers $abcd$ then you need to solve
$$10a+b+10c+d=10b+c \Rightarrow 10a+d= 9(b-c) \,.$$
Then
$$a+d \equiv 0 \pmod 9 \,,$$ and any pair $(a,d)$ which satisfies this relation uniquely determine $b-c$.
So fixing $a$ you get the value(s) of $d$ and from here $b-c$.
-
The answer is getting too long, so added this as a comment. The $a+d \equiv 0 \pmod 9$ is pretty obvious if you are familiar with $\pmod 9$ arithmetic: $$a+b+c+d \equiv ab+cd \equiv bc \equiv b+c \pmod 9$$ – N. S. Jul 12 '13 at 21:29 | {"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": 0.9134894609451294, "perplexity": 161.25298121456908}, "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-2014-42/segments/1413558067768.10/warc/CC-MAIN-20141017150107-00248-ip-10-16-133-185.ec2.internal.warc.gz"} |
https://www.gamedev.net/forums/topic/428296-infinite-parameters/ | # infinite parameters???
## Recommended Posts
DjMaSh 198
Hey, I'm not sure if this is possible but heres what I want to do. I want to define a function that can (theoretically) take an infinite amount of parameters. Is this possible without overloading a function an infinite amount of times? For example: int sum(int p1, int p2, int p3 , ... , int pn){ return p1 + p2 + ... + pn; } and then both these calls will call the same 'sum' function: sum(1, 2, 3); sum(1, 2, 3, 4, 5, 6, 7, 8, 9, 10); Or something... Would you need to use reg-exps or something? I dont know anything about them.
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pulpfist 528
I guess you could do that, or you can use a variable number of arguments (not recommended), but would'nt it be easier to use a vector argument?
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Enigma 1410
1. Why do you want to do this? 99.9% of the time there are better ways.
2. Somebody will doubtless recommend using the ellipsis operator (...) to declare a variable length argument list. In C this might be reasonable. In C++ see 1.
Σnigma
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You might want to look at this.
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cannonicus 136
I assume you are using c++.
Doing functions with variable numbers of parameters in c++ is ugly and trickey but possible. What you do is in your function declaration:
int sum(n, ...)
n is i.e. your number of terms to sum. The ... is called an ellipsis and it tells the compiler that this function has an unspecified number of arguments.
To access the variables passed to the function you use the type va_list and the macros va_start, va_args and va_end. Check out how on this site.
Now you can call your function by:
sum(5, 1, 2, 3, 4, 5);
Im not sure if you can get around having to pass the number of terms to sum though.
Hope it helps!
//Emil
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CandleJack 234
I'm pretty sure it's possible, as something like sprintf can take a varying number of arguments. I remember learning how sprintf worked a long time ago but my memory is a little fuzzy... I'll see if I can find my old notes and get back to you.
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DjMaSh 198
Quote:
Original post by EnigmaWhy do you want to do this? 99.9% of the time there are better ways.
I dont really have a purpose for it just yet, I just wanted to know if it is possible. It always comes into my mind and i think it would be handy everynow and then. Besides, what harm can a little more knowledge do?
And what about that .1%?
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Chjoodge 122
Quote:
Original post by cannonicusIm not sure if you can get around having to pass the number of terms to sum though.
Once inside the function with variable argument count, you have no way to determine how many arguments were passed. Either you have to send the argument count explicitly as an argument (like in your example), or you have to handle it somehow else (like reading the arguments until some "end" value is found).
In case of sprintf, the argument count is not passed explicitly, but one argument is loaded from the queue for each "%" found in the format string.
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pulpfist 528
Well the overloading is out of the question since we're talking about support for an infinite amount of arguments.
Variable argument list is like eating dinner with a baseball bat.
If you dont like using a vector for the job, I would rather suggest you overload the << operator.
#include <iostream>template<class digit_type>struct Adder{ Adder() : sum(0) {} digit_type sum; friend Adder& operator << (Adder& adder, const digit_type& digit) { adder.sum += digit; return adder; }};int main(){ Adder<int> adder; adder << 1 << 2 << 3; std::cout << adder.sum << std::endl; return 0;}
I made this little test so I might as well show it to you.
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ToohrVyk 1595
In this particular situation, there is no gain of using sum(x1,...xn) over plain old x1+...xn. In general, an operator-overloading approach, as illustrated above, is also a good option.
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Enigma 1410
Quote:
Original post by DjMaSh
Quote:
Original post by EnigmaWhy do you want to do this? 99.9% of the time there are better ways.
I dont really have a purpose for it just yet, I just wanted to know if it is possible. It always comes into my mind and i think it would be handy everynow and then. Besides, what harm can a little more knowledge do?
And what about that .1%?
OK. It just sounded from your original post that you wanted a solution to a specific problem. Of course it's useful to know about things like variable length argument lists. My warning was simply based on Hammer and Nail syndrome ("When your only tool is a hammer, every problem looks like a nail."). People who learn about variable argument lists have a tendency to then go and apply them in lots of situations. They seem neat at first, but have lots of subtle problems that can bite you quite hard.
Σnigma
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Register a new account | {"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": 0.19043444097042084, "perplexity": 1498.8173673332417}, "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-2017-34/segments/1502886104636.62/warc/CC-MAIN-20170818121545-20170818141545-00699.warc.gz"} |
http://inkpub.ieecas.cn/p/166/ | Spatio temporal change of urban heat island effect in Xining from Landsat image
： 2018 - 06 - 08
： 2018 - 09 - 29
： 2018 - 10 - 19
136 1 0
Abstract & Keywords
Abstract: Background, aim, and scope Withing the implementation of the western development policy, Xining entered a rapid development stage at the end of twentieth Century, and the scale of the city has been expanding, which has caused the urban heat island effect to become more and more prominent. Therefore, it is of great significance to study the spatial and temporal evolution characteristics and mitigation measures of urban heat island effect in Xining for the sustainable development of Xining. Compared with previous studies, the general urban heat island studies mostly take the urban administrative boundary as the suburb boundary. This paper takes the urban built-up area boundary as the urban and suburban boundary, and is relatively new. Materials and methods Using the Landsat satellite image from 1987 to 2015 and the same period of meteorological data and economic data, selected the single window algorithm to retrieve the surface temperature in Xining City from Landsat satellite image, combined with the thermal field variation and years of built-up area of the boundary,then the characteristics of temporal spatial evolution of Xining City urban heat island effect is analyzed in this paper. At the same time, the relationship between heat island intensity and vegetation, impervious surface, population and other factors was discussed. Finally, it puts forward the regulation measures of urban heat island effect in the process of urbanization. Result The results show that: (1) In summer in Xining city as "heat island" effect, "cold island" effect in winter. (2) The intensity of heat island in Xining city at the time is divided into three intervals, 1987~2000 years of heat island effect enhanced slowly from 2000 to 2003 is the rapid increase of 2003 to 2011, the heat island effect gradually weakened, from 2011 to 2015 the heat island effect, strength remained unchanged. (3) The same trend area of summer heat island area and trend of winter cold island, and built-up area change. Discussinon The change of the heat island area in Xining shows that 2000 has become an important time node for the change of thermal environment. Before 2000, the area of heat island in Xining increased little, but there was a sharp increase after 2000. This is due to the implementation of the western development policy. Xining has expanded rapidly in the original built-up area, making the city development from a single center to a multi center structure, and the increasing rate of greening can not catch up with the speed of development. Combined with the actual situation in Xining, this paper puts forward four relief measures for the heat island effect. (1) The artificial lakes should be dug near the industrial zone and the park. (2) Private cars should be controlled. (3) Green energy, such as abundant solar and wind energy in Qinghai Province (3) Construction the counties around Huangzhong, Huangyuan and other Xining cities to attract and disperse the population. Conclusions Research shows: (1) There was almost no change of heat island area in Xining before 2000. After 2000, the area of heat island area, especially the area of strong heat island area and medium heat island area, increased rapidly. In 2003, the area of heat island area reached the highest. From 2003 to 2011, the area of heat island gradually decreased, but increased again after 2011. (2) During the summer daytime, the intensity of urban heat island in Xining is positively correlated with the number of vehicles, built-up area, population and NDBI mean, and negatively correlated with urban greening rate, NDVI mean and BCI. (3) In winter daytime, the intensity of urban heat island in Xining is positively correlated with urban greening rate, NDVI, NDBI, BCI, and negatively correlated with the number of vehicles and built-up area. Recommendations and perspectives Due to the lack of remote sensing data and the poor quality of remote sensing data, the final screening image is not continuous in time, and the final result may lose some information. If there are more image data, better results should be obtained. In the study, it was found that during the winter, Xining was an obvious “cold island” in the daytime. Some studies have shown that the urban area in winter is “heat island” at night. However, due to the limitation of the imaging time of remote sensing data, the night thermal environment in the built area has not been studied in this paper. In future studies, we will focus on the heat island effect of winter nights in Xining.
Keywords: urban heat island effect; single window algorithm; land surface temperature retrieval; BCI; thermal field variability index; Xining City
1 研究区概况
Fig.1 Survey of study region
2 数据与方法
2.2 数据来源
2.3 研究方法
2.3.1 地表温度的遥感反演
$$\mathrm{T}={\mathrm{K}}_{2}/\mathrm{ln}\left(1+{\mathrm{K}}_{1}/{\mathrm{L}}_{\mathrm{\lambda }}\right)$$ （1）
$$\mathrm{\epsilon }=\mathrm{f}{\mathrm{\epsilon }}_{\mathrm{v}}+\left(1-\mathrm{f}\right){\mathrm{\epsilon }}_{\mathrm{i}}+{\mathrm{d}}_{\mathrm{\epsilon }}$$ （2）
$${\mathrm{d}}_{\mathrm{\epsilon }}=\left\{\begin{array}{c}0.0038f f\le 0.5\\ 0.0038\left(1-\mathrm{f}\right)f f＞0.5 \end{array}\right\$$ (3)
$$\mathrm{f}=\left(\mathrm{N}\mathrm{D}\mathrm{V}\mathrm{I}-{\mathrm{N}\mathrm{D}\mathrm{V}\mathrm{I}}_{\mathrm{m}\mathrm{i}\mathrm{n}}\right)/\left({\mathrm{N}\mathrm{D}\mathrm{V}\mathrm{I}}_{\mathrm{m}\mathrm{a}\mathrm{x}}-{\mathrm{N}\mathrm{D}\mathrm{V}\mathrm{I}}_{\mathrm{m}\mathrm{i}\mathrm{n}}\right)$$ (4)
像元类型 Pixel type NDVI取值范围 The value range of NDVI 地表比辐射率 Emissivity 水域 Waters NDVI﹤-0.180 $$\mathrm{\epsilon }=0.995$$ 裸土 Exposed soil -0.180≤NDVI﹤0.157 $$\mathrm{\epsilon }=0.972$$ 混合像元 Mixed pixel 0.157≤NDVI﹤0.886 $$\mathrm{\epsilon }=\mathrm{f}{\mathrm{\epsilon }}_{\mathrm{v}}+\left(1-\mathrm{f}\right){\mathrm{\epsilon }}_{\mathrm{i}}+{\mathrm{d}}_{\mathrm{\epsilon }}$$ 植被 Vegetative cove NDVI≥0.886 $$\mathrm{\epsilon }=0.986$$
$$\mathrm{\omega }=0.189\mathrm{P}+0.342$$ （5）
$$\mathrm{P}=0.6108\mathrm{*}\mathrm{e}\mathrm{x}\mathrm{p}\frac{17.27\left({\mathrm{T}}_{0}-273.15\right)}{237.3+\left({\mathrm{T}}_{0}-273.15\right)}\mathrm{*}\mathrm{R}\mathrm{H}$$ （6）
成像日期 Image acquired date 实测值 Measured value 估算值 estimate 夏季 Summer 1987.9.9 13.7 286.85 52 281.69 0.4961 0.9346 1995.8.16 17.3 290.45 69 285.03 0.5995 0.9263 2000.8.11 17.3 290.45 63 285.03 0.5771 0.9281 2003.9.20 9.8 282.95 72 278.08 0.5069 0.9337 2011.8.10 20.3 293.45 50 287.81 0.5671 0.9289 2015.8.21 13.3 286.45 66 281.32 0.5325 0.9317 冬季 winter 1989.2.10 -4.5 268.65 47 264.06 0.3809 0.9454 1995.1.5 -7.3 265.85 36 261.51 0.3660 0.9468 2000.10.3 2.2 275.35 56 270.17 0.4178 0.9419 2006.10.31 1.3 274.45 59 269.35 0.4168 0.9419 2013.12.5 -1.5 271.65 59 266.80 0.4030 0.9433 2015.1.9 -8.3 264.85 39 260.60 0.3661 0.9468
$$\mathrm{T}\mathrm{S}=\frac{1}{C}\left\{a\left(1-\mathrm{C}-\mathrm{D}\right)+\left[\left(\mathrm{b}-1\right)\left(1-\mathrm{C}-\mathrm{D}\right)+1\right]\mathrm{T}-\mathrm{D}{\mathrm{T}}_{\mathrm{a}}\right\}$$ （7）
$$\mathrm{C}=\mathrm{\epsilon }\mathrm{\tau }$$ (8)
$$\mathrm{D}\mathrm{ }=\mathrm{ }\left(1-\mathrm{\epsilon }\right)\mathrm{ }\left[1+\left(1-\mathrm{\epsilon }\right)\mathrm{\tau }\right]$$ (9)
2.3.2 基于热场变异指数的西宁市及辖区热岛定量分析
$$\mathrm{H}\mathrm{I}\left(\mathrm{T}\right)=\left(\mathrm{T}-{\mathrm{T}}_{\mathrm{M}\mathrm{E}\mathrm{A}\mathrm{R}}\right)/{\mathrm{T}}_{\mathrm{M}\mathrm{E}\mathrm{A}\mathrm{R}}$$ （10）
热场变异系数 Coefficient of heat field variation 热岛效应强度 Intensity of the heat island effect 生态评价指标 Ecologicalevaluating indicator ≤0 无 No 优Excellent 0～0.005 弱 Weak 良 Good 0.005～0.010 中Medium 一般Average 0.010～0.015 较强Strong 较差Fair ≥0.015 强Stronger 差 Poor
3 结果与分析
3.1 西宁市夏季“热岛”效应时空演变特征
3.1.1 夏季热岛区面积变化定量分析
Fig.2 The area change of different grade heat island area in Xining in summer
3.1.2 夏季热岛效应时空分布特征
Fig.3 The intensity distribution of heat island effect and the boundary of built-up area in Xining in summer
3.2 西宁市冬季热岛效应时空演变特征
3.2.1 冬季热岛区面积变化定量分析
Fig.4 The area change of different grade heat island area in Xining in winter
3.2.2 冬季热岛效应时空分布特征
Fig.5 The intensity distribution of heat island effect and the boundary of built-up area in Xining in summer
3.3热岛效应影响因子及其多元回归分析
指标类型 Index type 车辆 Cars 建成区面积 Area of built-up area 绿化率 Greening rate NDVI均值 NDVI (mean) NDBI 均值 NDBI (mean) BCI 均值 BCI (mean) 人口数 population HI(T) 车辆 Cars 1.000 － － － － － － － 建成区面积 Area of built-up area 0.989* 1.000 － － － － － － 绿化率 Greening rate 0.948* 0.970* 1.000 － － － － － NDVI均值NDVI(mean) 0.977* 0.974* 0.929* 1.000 － － － － NDBI均值NDBI(mean) -0.824* -0.832* -0.684* -0.800* 1.000 － － － BCI均值BCI(mean) -0.495* 0.521* -0.361* -0.493* 0.838* 1.000 － － 人口 population 0.837* 0.807* 0.880* 0.802* -0.390* 0.039* 1.000 － HI(T) 0.369* 0.421* -0.471* -0.502* 0.400* -0.340* 0.282* 1.000
*：表示相关性在0.05水平上显著。
*: indicates that the correlation of the parameters reaches a significant level p≤0.05.
指标类型 Index type 车辆 Cars 建成区面积 Area of built-up area 绿化率 Greening rate NDVI均值 NDVI (mean) NDBI 均值 NDBI (mean) BCI 均值 BCI (mean) 人口数 population HI(T) 车辆 Cars 1.000 － － － － － － － 建成区面积 Area of built-up area 0.953* 1.000 － － － － － － 绿化率 Greening rate 0.993* 0.940* 1.000 － － － － － NDVI均值NDVI(mean) 0.964* 0.872* 0.961* 1.000 － － － － NDBI均值NDBI(mean) 0.336* 0.037* 0.358* 0.456* 1.000 － － － BCI均值 BCI(mean) -0.548* -0.640* -0.561* -0.320* 0.411* 1.000 － － 人口 population 0.336* 0.037* 0.358* 0.456* 0.351* 0.111* 1.000 － HI(T) -0.177* -0.296* 0.148* 0.149* 0.349* 0.847* -0.094 1.000
*：表示相关性在0.05水平上显著。
*: indicates that the correlation of the parameters reaches a significant level p≤0.05.
4 讨论
5 结论
（1）1987—1995年，夏季白天，西宁市区和市郊温差不大，2000年以后，城市热源的分布明显增多，地表温度热源主要分布在三个区域：城市中心和居民新区等人口稠密的地区；工业园区；城区边缘地带的河谷裸土地。冬季白天，地表温度没有十分明显的高低极值，西宁市区从1989年起，就表现为一个“冷岛”。夏季的热岛区和冬季的冷岛区均随着西宁市城区发展有向东、西、南北四个方向扩展的趋势。
（2）西宁市热岛区面积变化在时间序列上有三个节点：2000年以前西宁市夏季和冬季白天各个热岛区面积变化不明显，2000年以后热岛区面积，尤其是较强热岛区面积和中热岛区面积都出现迅速增加的趋势；2003年热岛区面积达到最高，2003年以后热岛区面积渐渐回落；2011年以后又增强。
（3）夏季白天，热岛强度与西宁市区车辆数、建成区面积NDBI均值和人口数呈正相关，热岛强度与城市绿化率、城市NDVI均值、BCI指数呈负相关。冬季白天，西宁市热岛区面积与城市绿化率、NDVI均值、NDBI均值和BCI均值呈正相关，与市区车辆数、建成区面积呈负相关，相关系数分别为-0.177和-0.296，与人口的相关性不明显。
LIU Xuemei1, 2
GAO Xiaohong1
JIA Wei1
Natural Science Fund Project of Qinghai Provincial Science & Technology Department（2016-ZJ-907）
Journal of Earth Environment | {"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": 0.23298606276512146, "perplexity": 13799.736482654625}, "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/1566027323067.50/warc/CC-MAIN-20190825042326-20190825064326-00533.warc.gz"} |
https://kingsterfinance.com/inflation-and-purchasing-power/ | • Different goods and service have different inflation rates
• Inflation usually refers to Consumer (or Producer) Price Index which is a broad-based measurement of inflation across goods and services
Inflation measures the increase in price of goods or services.
If $1 could buy an apple last year and inflation was 50%. This year, the same$1 would only be able to purchase the equivalent of half an apple.
There are two perspectives to this situation.
The price of the apple had gone up or the value of the dollar had went down.
Either way, it could be said that the purchasing power of the dollar had decreased as it is able to buy less things.
## How is Inflation measured?
If an apple had its own inflation rate, it would make sense that other goods and services would also have their own inflation rate.
The inflation rate for an apple, TV, car, iPhone and haircut is all different.
These individual inflation rate does not mean much for consumers. As the price increment of an item could be matched by a price decrement of another.
There needs to be a broad-based measurement of inflation rate across goods and services. In this way, consumer would be able to know how much purchasing power the currency loses yearly.
Consumer Price Index (CPI) is a measurement of inflation across the various goods and services. There is also an inflation index, Producer Price Index, for goods and services that producers purchase.
However, there are some criticisms to the CPI.
Firstly, it understate the actual inflation rate as takes into account the increase in ‘usefulness’ of the product. 10 years ago, phones used to cost $300 and today it is common for it to cost$1000+. However, some of the price increment is treated as the increase in ‘usefulness’ — better camera, touch-screen, apps — and not due to inflation.
Secondly, it does not include all types of expenditure. It includes medical expenses that are paid by consumer but not those that are covered by insurance.
Regardless, it is still used as the main measurement for inflation.
## Causes of Inflation
In economics, it is common to mistake correlation with causation. In fact, many of these relationships are bi-directional and would reinforce one another.
Therefore, it is near impossible to distinguish them as indicators or causes of inflation.
Anyway , what is more important is the empirical evidence, whether the data agrees with the logic.
If they do not agree, it is likely that there are some nuances missed or flaw within the narrative. This method of probing one’s knowledge would allow investors to steer clear of noises from media or commonly propagated knowledge, and closer towards reality.
### Increase in Money Supply
In an economic expansion, the public tend to have a positive economic outlook.
Consumers borrow from banks to make new purchases, new car, good food.
Business borrow to increase their production capability. They believe that the debt incurred could be paid off in the future either by an increase in wages or sales.
These borrowing mechanism injects more money into the system.
Demand for goods and services, driving prices up.
Empirically, the correlation between money supply and inflation is relatively weak as shown in the graph.
In my opinion, the difference between what should be the logical relationship between money supply and inflation could be a result of where the extra money supply go.
The money supply needed to go into the real economy in order to cause inflation. However, there are times when the money supply enter the financial market more than it does the real economy.
The stock market and the real economy had been growing more detached in recent times.
There are many mechanisms that affect the money supply. Fiscal policies (stimulus), Quantitative Easing and interest rate (refinancing of debt).
Therefore, it is best not to jump to conclusion with this false ‘indicator’ of inflation.
### Increase in Money Velocity
An increase in money velocity have a similar effect to an increase in money supply.
A dollar spent on the purchase of an apple would be a dollar more in sales for the store owner. It is likely that he use it to buy more goods to stock up or increase the wages of his employees.
The dollar would circulate around the economy. A dollar could be spent multiple times by passing hands to the next person.
This is also known as the multiplier effect and is measured through money velocity.
The money velocity is more closely correlated to inflation than money supply.
Money supply could be up or down during recession as a result of policies implemented. While money velocity mostly decrease during recession.
Money velocity is a reflection of consumer’s confidence. If consumer is confident in the economy, they would spend more. Money would circulate more and inflation would go up.
## Decrease in Interest Rate
I would start with the common knowledge of interest rate and its relationship with inflation.
A decrease in interest causes a rise in inflation. Consumers and businesses are encouraged to borrow and spend when interest rate fall.
A consumer that is looking to purchase a house might delay it as interest rate (mortgage) is too high. When interest rate falls, the loan would be more appealing and more people would borrow.
Logically, that makes a lot of sense. But how does it fare against the data?
Interest rate instead of being negatively correlated to inflation, it is relatively positively correlated.
Perhaps it is the decreasing inflation rate that pushes interest rate down? The causal relationship might be opposite from conventional knowledge.
Some economists even suggest that the rising interest rate would spur inflation!
It is best not to jump to any conclusion about causality between interest rate and inflation. Interest rate does not have clear causal relationship with inflation against what most think.
Just remember that they are positively correlated.
### Decrease in Supply of Goods & Services
All previous factors affect the price of goods through the demand side of things.
However, it is also possible to cause inflation by having a lack in supply of goods. Its just that technology pushes the world’s production capability higher.
## Conclusion
Inflation could be seen as the currency losing its purchasing power. A dollar would be able to purchase less things (in aggregate) the next year.
The main measurement that investors use to measure inflation is CPI. Producer Price Index could also be used though not as common.
Increase in money supply does not necessary cause inflation as it depends on where the money goes to. Real economy, financial market or saved up in bank deposit.
Increase in money velocity has been shown to have quite a close positive correlation with inflation. They tend to go up and down together. One reason might be that money velocity measures the ‘flow of money’ in the real economy, not taking into account the financial market.
Interest rate also has a positive correlation with inflation. Though the causal relationship is a bit complicated.
Inflation could also happen from the supply side of things, through a decrease in supply.
In the next article, we would touch on the assets that tend to perform during inflation. | {"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": 0.2121124267578125, "perplexity": 1688.6451994388167}, "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-2021-17/segments/1618038879305.68/warc/CC-MAIN-20210419080654-20210419110654-00425.warc.gz"} |
https://www.physicsforums.com/threads/finding-distance-between-two-slits-in-conditions-related-to-youngs-experiment.144017/ | # Homework Help: Finding distance between two slits in conditions related to Young's Experiment
1. Nov 15, 2006
### wScott
Good evening to all you genius people out there, I've been racking my brains for the past 10 minutes and cant come up with anything.
The exact wording of the question:
Describe how you could use light of a known wavelength to find the distance between two slits.
I thought of using distance = wavelength/ sin(theta). But then I realized I'm not given the angle. Got any suggestions for this predicament?
2. Nov 15, 2006
### physics girl phd
Hint -- Do you know what the "far field" pattern looks like when you send monochromatic (and coherent) light through two neighboring slits? the angle will come from something about that. | {"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": 0.8603038191795349, "perplexity": 1264.616885422065}, "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/1544376825495.60/warc/CC-MAIN-20181214070839-20181214092339-00080.warc.gz"} |
https://docs.mitk.org/2022.04/org_mitk_views_segmentation.html | Medical Imaging Interaction Toolkit 2022.04.00 Medical Imaging Interaction Toolkit
The Segmentation View
Icon of the segmentation view
Some of the features described below are closed source additions to the open source toolkit MITK and are not available in every application.
Overview
Segmentation is the act of partitioning an image into subsets by either manual or automated delineation to create i.e. a distinction between foreground and background. A multilabel segmentation can contain more than one label and more than one layer. This allows you to create different labels for different regions of interest encapsulated in one single image. The difference between labels and layers is that labels on one layer cannot overlap but labels on different layers can.
The MITK segmentation plugin allows you to create multilabel segmentations of anatomical and pathological structures in medical images. The plugin consists of two views:
In this documentation, the features and usage of the segmentation view will be described. For an introduction to the segmentation utilities please be referred to the respective documentation pages.
Segmentation plugin overview
Preferences
The segmentation plugin offers a number of preferences which can be set via the MITK Workbench application preferences:
Segmentation preferences
• Slim view: Allows to show or hide the tool button description of the segmentation view
• 2D display: Specify whether the segmentation is drawn as outline or as a transparent overlay
• Show only selected nodes: Enable if only the selected segmentation and the reference image should be visible
• Smoothed surface creation: Set certain smoothing parameters for surface creation
• Default label set preset: Start a new segmentation with this preset instead of a default label
Technical issues
The segmentation plugin makes a number of assumptions:
• Images must be 2D, 3D, or 3D+t.
• Images must be single-values, i.e. CT, MRI or "normal" ultrasound. Images from color doppler or photographic (RGB) images are only partially supported (please be aware that some tools might not be compatible with this image type).
• Segmentations are handled as multilabel images of the same extent as the original image.
Data selection & creating new segmentations
To select a reference image for the segmentation, click on the Selected image selection widget and choose a suitable image from the selection available in the data manager. Once an image is selected, a new segmentation can be created on this reference image by clicking the button to the right of the Selected segmentation selection widget. A new multilabel segmentation with an initial label is automatically generated. The new segmentation will be added to the data manager as sub-node of the reference image. This item is then automatically selected in the data selection, which allows to start editing the new segmentation right away.
Data selection
Alternatively to creating a new segmentation, an existing one can be edited as well. If a reference image is selected for which a segmentation already exists in the data manager, the auto selection mode will automatically select a fitting segmentation. Clicking on the segmentation selection widget a drop down list will open, containing all suitable segmentations for the selected reference dataset available in the data manager.
Segmentation layers
For each multilabel segmentation different layers can be added or deleted. The layers can be used independently and layers can be switched using the left and right arrows. A layer is a set of labels that occupy a non-overlapping anatomical space. The best way to describe them is by a real use case: Imagine you are working on a radiotherapy planning application. In the first layer of your segmentation session, you would like to trace the contours of the liver and neighboring organs. You can accommodate all these segmentations in separate labels because they all occupy different anatomical regions and do not overlap. Now say you would like to segment the arteries and veins inside the liver. If you don't trace them in a different layer, you will overwrite the previous ones. You may also need a third layer for segmenting the different irrigation territories in the liver and a fourth layer to contain the lesion you would like to treat.
Layer selection
Segmentation labels
For each layer, one or more labels can be added. Pressing the double arrow on the right, all created labels are shown in the 'Label Table'. The following label properties are available:
• Name: the name of the label. Can be a predefined one or any other.
• Locked: whether the label is locked or editable. A locked label cannot be overwritten by another.
• Color: the color of the label.
• Visible: whether the label is currently visible or hidden.
The 'Label Table' shows all labels in the current segmentation session
The 'New Label' button can be used to add a new label. This will automatically add a new label with a distinct name and color to the list of available labels.
In the current implementation of the plugin, the maximum number of labels is restricted to 255. If you need more, you will have to create a new segmentation session.
Label set presets are useful to share a certain style or scheme between different segmentation sessions or to provide templates for new segmentation sessions.
The properties of all labels in all layers like their names, colors, and visibilities are saved as a label set preset by clicking on the 'Save label set preset' button. Label set presets are applied to any segmentation session by clicking on the 'Load label set preset' button. If a label for a certain value already exists, its properties are overridden by the preset. If a label for a certain value does not yet exist, an empty label with the label properties of the preset is created. The actual segmentations of labels are unaffected as label set presets only store label properties.
Applying label set presets by default
If you work on a repetetive segmentation task, manually loading the same label set preset for each and every new segmentation can be tedious. To streamline your workflow, you can set a default label set preset in the Segmentation preferences (Ctrl+P). When set, this label set preset will be applied to all new segmentations instead of creating the default red "New label 1" label.
Searching for a label
It may happen that many labels (e.g. > 200) are present in a segmentation session and therefore manual searching can be time-consuming. The 'Label Search' edit box allows for quickly finding a label by providing assistance for label name completion. If the label is found, it will become the active one after pressing 'enter'.
To start editing a label needs to be activated by clicking on the corresponding row in the 'Label Table'. Only one label can be active at the time. Then the segmentation tools in the toolbox can be used for mask generation.
Operations on labels
Depending on the selection in the 'Label Table', several actions are offered:
Operations with single label selection
Right-clicking on any label opens a pop-up menu that offers the following actions to be performed on the selected label:
• Rename... : change the name and / or color of the selected label.
• Remove... : delete the selected label.
• Erase... : only clear the contents of the selected label.
• Merge... : merge two labels by selecting a second label.
• Random color : assign a random color to the label.
• View only : make all labels except the current selected label invisible.
• View/Hide all : make all labels visible / invisible
• Lock/Unlock all : lock or unlock all labels.
• Create surface : generate a surface out of the selected label.
• Create mask : generate a mask out of the selected label. A mask is a binary image with "1" inside and "0" outside.
• Create cropped mask : generate a binary mask out of the selected label. Crop changes the extent of the resulting image to the extent of the label.
Context menu for single label selection
Operations with multiple label selection
Shift-clickink on multiple labels allows to select more than one label. If more than one label is selected, different options will appear in the menu:
• Merge selection on current label : transfer the contents of the selected labels in the 'Label Table' into the current one.
• Remove selected labels : delete the selected labels.
• Erase selected labels : only clear the contents of the selected labels.
Context menu for multiple label selection
Segmentation tool overview
MITK offers a comprehensive set of slice-based 2D and (semi-)automated 3D segmentation tools. The manual 2D tools require some user interaction and can only be applied to a single image slice whereas the 3D tools operate on the whole image. The 3D tools usually only require a small amount of user interaction, i.e. placing seed points or setting / adjusting parameters. You can switch between the different toolsets by selecting the 2D or 3D tab in the segmentation view.
An overview of the existing 2D and 3D tools in MITK.
2D segmentation tools
With 2D manual contouring you define which voxels are part of the segmentation and which are not. This allows you to create segmentations of any structures of interest in an image. You can also use manual contouring to correct segmentations that result from sub-optimal automatic methods. The drawback of manual contouring is that you might need to define contours on many 2D slices. However, this is mitigated by the interpolation feature, which will make suggestions for a segmentation.
To start using one of the editing tools, click its button from the displayed toolbox. The selected editing tool will be active and its corresponding button will stay pressed until you click the button again. Selecting a different tool also deactivates the previous one.
If you have to delineate a lot of images, shortcuts to switch between tools becomes convenient. For that, just hit the first letter of each tool to activate it (A for Add, S for Subtract, etc.).
All of the editing tools work by the same principle: using the mouse (left button) to click anywhere in a 2D window (any of the orientations axial, sagittal, or coronal), moving the mouse while holding the mouse button and releasing the button to finish the editing action. Multi-step undo and redo is fully supported by all editing tools by using the application-wide undo / redo buttons in the toolbar.
Remark: Clicking and moving the mouse in any of the 2D render windows will move the crosshair that defines what part of the image is displayed. This behavior is disabled as long as any of the manual segmentation tools are active - otherwise you might have a hard time concentrating on the contour you are drawing.
Use the left mouse button to draw a closed contour. When releasing the mouse button, the contour will be added (Add tool) to or removed (Subtract tool) from the current segmentation. Adding and subtracting voxels can be iteratively repeated for the same segmentation. Holding CTRL / CMD while drawing will invert the current tool's behavior (i.e. instead of adding voxels, they will be subtracted).
Paint and wipe tools
Paint and wipe tools
Use the Size slider to change the radius of the round paintbrush tool. Move the mouse in any 2D window and press the left button to draw or erase pixels. Holding CTRL / CMD while drawing will invert the current tool's behavior (i.e. instead of painting voxels, they will be wiped).
Region growing tool
Region growing tool
Click at one point in a 2D slice widget to add an image region to the segmentation with the region growing tool. Region Growing selects all pixels around the mouse cursor that have a similar gray value as the pixel below the mouse cursor. This allows to quickly create segmentations of structures that have a good contrast to surrounding tissue. The tool operates based on the current level window, so changing the level window to optimize the contrast for the ROI is encouraged. Moving the mouse up / down is different from left / right: Moving up the cursor while holding the left mouse button widens the range for the included grey values; moving it down narrows it. Moving the mouse left and right will shift the range. The tool will select more or less pixels, corresponding to the changing gray value range.
Fill tool
Fill tool
Left-click inside a segmentation with holes to completely fill all holes. Left-click inside a hole to fill only this specific hole.
Erase tool
Erase tool
This tool removes a connected part of pixels that form a segmentation. You may use it to remove single segmentations (left-click on specific segmentation) or to clear a whole slice at once (left-click outside a segmentation).
Live wire tool
Live wire tool
The Live Wire Tool acts as a magnetic lasso with a contour snapping to edges of objects.
Steps for using the Live Wire Tool
• (1) To start the tool you have to double-click near the edge of the object you want to segment. The initial anchor point will snap to the edge within a 3x3 region.
• (2) Move the mouse. You don't have trace the edge of the object. The contour will automatically snap to it.
• (3) To fix a segment you can set anchor points by single left mouse button click.
• (4) Go on with moving the mouse and setting anchor points.
• (5) To close the contour double-click on the initial anchor point.
• (6) After closing, the contour can be edited by moving, inserting and deleting anchor points.
The contour will be transferred to its binary image representation by deactivating the tool.
2D and 3D Interpolation
Creating segmentations using 2D manual contouring for large image volumes may be very time-consuming, because structures of interest may cover a large range of slices. Note: Interpolation is currently disabled for segmentations containing more than one label. The segmentation view offers two helpful features to mitigate this drawback:
• 2D Interpolation
• 3D Interpolation
The 2D Interpolation creates suggestions for a segmentation whenever you have a slice that
• has got neighboring slices with segmentations (these do not need to be direct neighbors but could also be a couple of slices away) AND
• is completely clear of a manual segmentation, i.e. there will be no suggestion if there is even only a single pixel of segmentation in the current slice.
2D interpolation usage
Interpolated suggestions are displayed as outlines, until you confirm them as part of the segmentation. To confirm single slices, click the Confirm for single slice button below the toolbox. You may also review the interpolations visually and then accept all of them at once by selecting Confirm for all slices.
The 3D interpolation creates suggestions for 3D segmentations. That means if you start contouring, from the second contour onwards, the surface of the segmented area will be interpolated based on the given contour information. The interpolation works with all available manual tools. Please note that this is currently a pure mathematical interpolation, i.e. image intensity information is not taken into account. With each further contour the interpolation result will be improved, but the more contours you provide the longer the recalculation will take. To achieve an optimal interpolation result and in this way a most accurate segmentation you should try to describe the surface with sparse contours by segmenting in arbitrary oriented planes. The 3D interpolation is not meant to be used for parallel slice-wise segmentation, but rather segmentations in i.e. the axial, coronal and sagittal plane.
3D interpolation usage
You can accept the interpolation result by clicking the Confirm-button below the tool buttons. In this case the 3D interpolation will be deactivated automatically so that the result can be post-processed without any interpolation running in the background.
Additional to the surface, black contours are shown in the 3D render window, which mark all the drawn contours used for the interpolation. You can navigate between the drawn contours by clicking on the corresponding position nodes in the data manager which are stored as sub-nodes of the selected segmentation. If you do not want to see these nodes just uncheck the Show Position Nodes checkbox and these nodes will be hidden.
If you want to delete a drawn contour we recommend to use the Erase-Tool since undo / redo is not yet working for 3D interpolation. The current state of the 3D interpolation can be saved across application restart. For that, just click on save project during the interpolation is active. After restarting the application and load your project you can click on "Reinit Interpolation" within the 3D interpolation GUI area.
3D segmentation tools
The 3D tools operate on the whole image and require usually a small amount of interaction like placing seed-points or specifying certain parameters. All 3D tools provide an immediate segmentation feedback, which is displayed as a transparent green overlay. For accepting a preview you have to press the Confirm button of the selected tool. The following 3D tools are available:
3D Threshold tool
The thresholding tool simply applies a 3D threshold to the patient image. All pixels with values equal or above the selected threshold are labeled as part of the segmentation. You can change the threshold by either moving the slider of setting a certain value in the spinbox.
3D Threshold tool
3D upper / lower threshold tool
The Upper/Lower Thresholding tool works similar to the simple 3D threshold tool but allows you to define an upper and lower threshold. All pixels with values within this threshold interval will be labeled as part of the segmentation.
3D upper / lower threshold tool
3D Otsu tool
The 3D Otsu tool provides a more sophisticated thresholding algorithm. It allows you to define a number of regions. Based on the image histogram the pixels will then be divided into different regions. The more regions you define the longer the calculation will take. You can select afterwards which of these regions you want to confirm as segmentation.
3D Otsu tool
3D Region growing tool
The 3D Region Growing tool works similar to the 2D pendant. At the beginning you have to place a seedpoint and define a threshold interval. If you press Run Segmentation a preview is calculated. By moving the Adapt region growing slider you can interactively adapt the segmentation result.
3D Region growing tool
Picking Tool
The Picking tool allows you to select islands within your segmentation. This is especially useful if e.g. a thresholding provided you with several areas within your image but you are just interested in one special region.
Picking tool
nnU-Net Tool (Ubuntu only)
nnUNet tool
This tool provides a GUI to the deep learning-based segmentation algorithm called the nnUNet. With this tool, you can get a segmentation mask predicted for the loaded image in MITK. Be ready with the pre-trained weights (a.k.a RESULTS_FOLDER) for your organ or task concerned, before using the tool. For a detailed explanation of the parameters and pre-trained weights folder structure etc., please refer to https://github.com/MIC-DKFZ/nnUNet.
Remark: The tool assumes that you have a Python3 environment with nnUNet (pip) installed. Your machine should be also equipped with a CUDA enabled GPU.
Workflow:
1. Select the "Python Path" drop-down to see if MITK has automatically detected other Python environments. Click on a fitting environment for the nnUNet inference or click "Select" in the dropdown to choose an unlisted python environment. Note that, while selecting an arbitrary environment folder, only select the base folder, e.g. "myenv". No need to select all the way until "../myenv/bin/python", for example.
2. Click on the "nnUNet Results Folder" directory icon to navigate to the results folder on your hard disk. This is equivalent to setting the RESULTS_FOLDER environment variable. If your results folder is as per the nnUNet required folder structure, the configuration, trainers, tasks and folds are automatically parsed and correspondingly loaded in the drop-down boxes as shown below. Note that MITK automatically checks for the RESULTS_FOLDER environment variable value and, if found, auto parses that directory when the tool is started.
nnUNet Segmentation Settings
3. Choose your required Task-Configuration-Trainer-Planner-Fold parameters, sequentially. By default, all entries are selected inside the "Fold" dropdown (shown: "All"). Note that, even if you uncheck all entries from the "Fold" dropdown (shown: "None"), then too, all folds would be considered for inferencing.
4. For ensemble predictions, you will get the option to select parameters irrespective on postprocessing files available in the ensembles folder of RESULTS_FOLDER. Note that, if a postprocessing json file exists for the selected combination then it will used for ensembling, by default. To choose not to, uncheck the "Use PostProcessing JSON" in the "Advanced" section.
nnUNet Segmentation Settings
5. If your task is trained with multi-modal inputs, then "Multi-Modal" checkbox is checked and the no.of modalities are preloaded in the "No. of Extra Modalities" spinbox. Instantly, as much node selectors with corresponding modality names should appear below to select the Data Manager along including a selector with preselected with the reference node. Now, select the image nodes in the node selectors accordingly for accurate inferencing.
nnUNet Multi Modal Settings
6. Click on "Preview".
7. In the "Advanced" section, you can also activate other options like "Mixed Precision" and "Enable Mirroring" (for test time data augmentation) pertaining to nnUNet.
8. Use "Advanced" > "GPU Id" combobox to change the preferred GPU for inferencing. This is internally equivalent to setting the CUDA_VISIBLE_DEVICES environment variable.
9. Every inferred segmentation is cached to prevent a redundant computation. In case, a user doesn't wish to cache a Preview, uncheck the "Enable Caching" in the "Advanced" section. This will ensure that the current parameters will neither be checked against the existing cache nor a segmentation be loaded from it when Preview is clicked.
10. You may always clear all the cached segmentations by clicking "Clear Cache" button.
Miscellaneous:
1. In case you want to reload/reparse the folders in the "nnUNet Results Folder", eg. after adding new tasks into it, you may do so without reselecting the folder again by clicking the "Refresh Results Folder" button.
2. The "Advanced" > "GPU Id" combobox lists the Nvidia GPUs available by parsing the nvidia-smi utility output. In case your machine has Nvidia CUDA enabled GPUs but the nvidia-smi fails for some reason, the "GPU Id" combobox will show no entries. In such a situation, it's still possible to execute inferencing by manually entering the preferred GPU Id, eg. 0 in the combobox.
3. In the RESULTS_FOLDER directory, inside the trainer-planner folder of every task, MITK keeps a "mitk_export.json" file for fast loading for multi-modal information. It is recommended not to delete this file(s) for a fast responsive UI. Tip: If multi-modal information shown on MITK is not correct for a given task, you may modify this JSON file and try again.
Additional things you can do with segmentations
Segmentations are never an end in themselves. Consequently, the segmentation view adds a couple of "post-processing" actions, accessible through the context-menu of the data manager.
• Create polygon model applies the marching cubes algorithm to the segmentation. This polygon model can be used for visualization in 3D or other applications such as stereolithography (3D printing).
• Create smoothed polygon model uses smoothing in addition to the marching cubes algorithm, which creates models that do not follow the exact outlines of the segmentation, but look smoother.
• Autocrop can save memory. Manual segmentations have the same extent as the patient image, even if the segmentation comprises only a small sub-volume. This invisible and meaningless margin is removed by autocropping.
Segmentation of 3D+t images
For segmentation of 3D+t images, some tools give you the option to choose between creating dynamic and static masks.
• Dynamic masks can be created on each time frame individually.
• Static masks will be defined on one time frame and will be the same for all other time frames.
In general, segmentation is applied on the time frame that is selected when execution is performed. If you alter the time frame, the segmentation preview is adapted.
Technical information for developers
For technical specifications see Technical design of QmitkSegmentation and for information on the extensions of the tools system How to extend the Segmentation view with external tools. | {"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": 0.17250482738018036, "perplexity": 2716.7893183033407}, "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-2023-14/segments/1679296943637.3/warc/CC-MAIN-20230321064400-20230321094400-00723.warc.gz"} |
https://es.mathworks.com/help/robust/ref/lti.slowfast.html | # slowfast
Slow and fast modes decomposition
## Syntax
```[G1,G2] = slowfast(G,ns)
```
## Description
`slowfast` computes the slow and fast modes decompositions of a system G(s) such that
G(s) = [G1(s)] + [G2(s)]
`G(s)` contains the `N` slowest modes (modes with the smallest absolute value) of `G`.
$\left[{G}_{1}\left(s\right)\right]:=\left({\stackrel{^}{A}}_{11},{\stackrel{^}{B}}_{1},{\stackrel{^}{C}}_{1},{\stackrel{^}{D}}_{1}\right)$ denotes the slow part of G(s). The slow poles have low frequency and magnitude values.
$\left[{G}_{2}\left(s\right)\right]:=\left({\stackrel{^}{A}}_{22},{\stackrel{^}{B}}_{2},{\stackrel{^}{C}}_{2},{\stackrel{^}{D}}_{2}\right)$ denotes the fast part. The fast poles have high frequency and magnitude values.
The variable `ns` denotes the index where the modes will be split.
Use `freqsep` to separate slow and fast modes at a specified cutoff frequency instead of a specified number of modes.
## References
M.G. Safonov, E.A. Jonckheere, M. Verma and D.J.N. Limebeer, “Synthesis of Positive Real Multivariable Feedback Systems”, Int. J. Control, vol. 45, no. 3, pp. 817-842, 1987.
## Version History
Introduced before R2006a | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 2, "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": 0.9787383079528809, "perplexity": 5760.170203519668}, "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/1664030337287.87/warc/CC-MAIN-20221002052710-20221002082710-00625.warc.gz"} |
https://cs.uwaterloo.ca/usra | # NSERC USRA program
The NSERC Undergraduate Student Research Award (USRA) is a financial award that allows outstanding undergraduate students to work with a faculty member in an academic research environment for a semester.
USRA recipients take part in a research project in an area of Computer Science, under the direction and guidance of a supervisor. The type of work will vary depending on the supervisor, the project, and the student's background.
If you are interested in exploring the research side of academic life or if your goal is graduate studies in a field related to Computer Science, the experience of an NSERC USRA could be very helpful.
###### Meet Victor
Victor spent his Winter 2022 work term with Professor Yaoliang Yu, working on the convergence analysis of the expectation-maximization algorithm. Victor’s role was to review the relevant literature for prior techniques and work on mathematics to generalize or improve existing convergence analysis.
“One important aspect of research that I learned with Prof. Yaoliang Yu is the fact that it is important to go back and refocus on the bigger picture. Often when I am working on a specific topic, many ideas come to mind to explore, but not all of them are fruitful. It may so happen that I go on some tangents, but I learned that it is important always to remind myself of the final goal.
I recommend other undergraduate students to pursue a co-op term in research because there are many opportunities to do industry co-ops, but it may happen that research is their calling. However, they would not know unless they tried it!” Victor Liao, BCS candidate
Competitions for NSERC USRA's are held three times each year. Deadlines for computer science students are as follows:
Spring 2023 Closed
Fall 2023 Monday, May 8, 2023
Winter 2024 TBC
Check with Jessica Rosa-Vecchiarelli for specific dates.
Please note: No applications will be accepted past the deadline; the application process is on a tight schedule and we cannot accommodate late applications.
### Length of project
• Full-time (35 hours per week) for 16 consecutive weeks (80 working days).
• Can be counted as a co-op work term but you do not need to be a co-op student to be eligible for this award.
*Note: A student is not allowed to be taking courses full-time or working on another project/job while doing the USRA as it is considered a full-time job.
### Compensation for 2022/2023
• For Spring 2021 onwards, $6,000 from the award portion plus the supervisor's contribution. The recommended minimum amount for the supervisor’s contribution is$3027.20 per term (or $756.80 per month), giving a total minimum payment for the term of$9,027.20
• Does not include benefits or vacation pay.
• The student and/or the supervisor can apply for President's Scholarships to supplement the supervisor's contribution.
### Eligibility
###### Student eligibility
• Must have completed one full year of school before starting the USRA, i.e., 2A or higher (students can be in 1B when they apply, and students can do a USRA in the term immediately after degree completion, but not later than this).
• Must have a 75% cumulative average or higher (for Fall 2021 and Winter 2022, students must have a cumulative average of 80% or higher).
• Must find a faculty supervisor before applying.
• Must have only one USRA per NSERC fiscal year (April 1 - March 31).
• Maximum of three USRAs during undergraduate degree.
• Cannot have started a graduate degree or be involved in full-time research and development in natural sciences or engineering.
###### Supervisor eligibility
Supervisors must meet one of the following criteria:
• Hold an active research grant from NSERC, or an eligible tri-agency research grant administered jointly by NSERC, CIHR, and SSHRC, by the beginning of the USRA term. If you are unsure whether your grant is eligible and/or if you have applied to a grant, but have yet to hear your results, please email Jessica Rosa-Vecchiarelli
• Be a newly appointed Assistant Professor.
### How to apply
1. Ensure that you meet the eligibility requirements outlined above.
2. Find a supervisor with whom you would like to work. Contact Jessica Rosa-Vecchiarelli for advice or if you are open to the field of study.
3. Decide on a research project and clearly define your role and responsibilities with the supervisor.
4. Complete the following on the NSERC online system
1. Complete and submit Form 202 - Part I.
2. Upload your unofficial transcript if you are a UW student. Otherwise, non-UW students must upload an official transcript (with a legend attached, if applicable).
3. Send your reference number to your supervisor (the supervisor will use the student’s reference number to create and link form 202 Part II).
5. Ensure that your supervisor completes the online application (Form 202 - Part II).
6. Email Jessica Rosa-Vecchiarelli when Form 202 (Part I and II) is completed by the student and supervisor before the deadline (see 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": 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": 0.3910679817199707, "perplexity": 2567.869207059062}, "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/1679296948871.42/warc/CC-MAIN-20230328201715-20230328231715-00396.warc.gz"} |
http://en.paddlepaddle.org/documentation/docs/en/1.2/design/concepts/README.html | A few months ago when we were trying to replace CMake with Bazel, @emailweixu suggested that we rewrite those handy Bazel functions using CMake. Now it seems that it's the right time to get this done, as we are facing problems from the porting of Majel and the development of new the parameter server using Go and C++.
# Required CMake Function
I think we need only the following few CMake functions to make a project description mean and clean:
C++ CUDA C++ Go
cc_library nv_library go_library
cc_binary nv_binary go_binary
cc_test nv_test go_test
• The _library functions generate .a files from source code.
• The _binary functions generate executable binary files.
• The _test functions generate executable unit test files. They work like _binary but links -lgtest and -lgtest_main.
The difference between nv_ functions and cc_ functions is that the former use nvcc instead of the system-default C++ compiler.
Both nv_ and cc_ functions enables C++11 (-std=c++11).
Also,
• to describe external dependencies, we need external_library.
• to build shared libraries, we need shared_library.
## An Example Project
Suppose that we have aforementioned functions defined in our /cmake directory. The following example CMakeLists.txt describes a project including the following source files:
• tensor.h
• tensor.cc
• tensor_test.cc
• ops.h
• ops.cu
• ops_test.cu
• api.go
• api_test.go
Suppose that ops.cu depends on CUDNN.
# cc_binary parses tensor.cc and figures out that target also depend
# on tensor.h.
cc_binary(tensor
SRCS
tensor.cc)
# The dependency to target tensor implies that if any of
# tensor{.h,.cc,_test.cc} is changed, tensor_test need to be re-built.
cc_test(tensor_test
SRCS
tensor_test.cc
DEPS
tensor)
# I don't have a clear idea what parameters external_library need to
# have. @gangliao as a CMake expert would have better ideas.
external_library(cudnn
....)
# Suppose that ops.cu depends on external target CUDNN. Also, ops.cu
# include global functions that take Tensor as their parameters, so
# ops depend on tensor. This implies that if any of tensor.{h.cc},
# ops.{h,cu} is changed, ops need to be re-built.
nv_library(ops
SRCS
ops.cu
DEPS
tensor
cudnn) # cudnn is defined later.
nv_test(ops_test
SRCS
ops_test.cu
DEPS
ops)
# Because api.go defines a GO wrapper to ops and tensor, it depends on
# both. This implies that if any of tensor.{h,cc}, ops.{h,cu}, or
# api.go is changed, api need to be re-built.
go_library(api
SRCS
api.go
DEPS
tensor # Because ops depend on tensor, this line is optional.
ops)
go_test(api_test
SRCS
api_test.go
DEPS
api)
# This builds libapi.so. shared_library might use CMake target
# api_shared so to distinguish it from above target api.
shared_library(api
DEPS
api)
## Implementation
As above example CMakeLists.txt executes, each function invocation adds "nodes" to a dependency graph. It also use this graph to generate CMake commands including add_executable, add_dependencies, target_link_libraries, and add_test.
## Using Package Manager For Go
Building Go binaries and libraries need to satisfy their dependencies, generally we can do go get ./... to download and compile all external dependencies. The problems are:
1. go get will always get the latest code from the default branch of the remote repo, so changes of dependents might break the build. This is very different with what we already have in cmake/external which download a specific version or commit id of the dependency.
2. Some locations can not access external dependencies through the internet, as mentioned in https://github.com/PaddlePaddle/Paddle/issues/2605. Using package management tools can package the dependencies as a "vendor" package, which can be mirrored at many cloud file hosting, so users what to compile paddle by themselves can download this "vendor" package from a mirror site.
### Choose A Suitable Tool
As mentioned by @wangkuiyi, Here list dozens of Go package managers. We choose the tool using following principles:
• Most "active" projects with more stars, more pull requests or commits
• Widely used project
After comparing all these projects, we shall choose between the most popular tools: Godep and Glide.
Here's a brief comparison between Godep and Glide : https://github.com/Masterminds/glide/wiki/Go-Package-Manager-Comparison. There are also many complaints about using Godep. There's also a new "official" pakcage management tool has been started at: https://github.com/golang/dep to resolve such problems, but it's currently at Alpha stage. So the best choice now is glide obviously.
### Manage Go Packages
• Dependencies: go/glide.yaml will store the dependencies and their versions which is directly imported by paddle. go/glide.lock will store all dependencies recursively with their commit id. Builds will "lock" to these packages if we don't glide up them
• Vendor package: go/vendor directory will generated when running cmake command. cmake will download the code corresponding to go/glide.lock. If we put a vendor folder under go/, cmake will just check the commit id to the packages under the folder, if commit id matches, there will be no download at 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": 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": 0.44196462631225586, "perplexity": 9674.751918464533}, "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-2019-22/segments/1558232255251.1/warc/CC-MAIN-20190520001706-20190520023706-00534.warc.gz"} |
http://pdglive.lbl.gov/ParticleGroup.action;jsessionid=713CDCCEA231F9B59ECE13077BF54AB5?node=BXXX025&init=0 | # ${{\mathit \Sigma}}$ BARYONS ($\mathit S$ = $-1$, $\mathit I$ = 1)
${{\mathit \Sigma}^{+}}$ = ${\mathit {\mathit u}}$ ${\mathit {\mathit u}}$ ${\mathit {\mathit s}}$, ${{\mathit \Sigma}^{0}}$ = ${\mathit {\mathit u}}$ ${\mathit {\mathit d}}$ ${\mathit {\mathit s}}$, ${{\mathit \Sigma}^{-}}$ = ${\mathit {\mathit d}}$ ${\mathit {\mathit d}}$ ${\mathit {\mathit s}}$
Review: The ${{\mathit \Sigma}{(1670)}}$ Region
${{\mathit \Sigma}^{+}}$ **** ${{\mathit \Sigma}^{0}}$ **** ${{\mathit \Sigma}^{-}}$ **** ${{\mathit \Sigma}{(1385)}}$ $3/2{}^{+}$ **** ${{\mathit \Sigma}{(1480)}}$ Bumps * ${{\mathit \Sigma}{(1560)}}$ Bumps ** ${{\mathit \Sigma}{(1580)}}$ $3/2{}^{-}$ * ${{\mathit \Sigma}{(1620)}}$ $1/2{}^{-}$ * ${{\mathit \Sigma}{(1620)}}$ Production Experiments ${{\mathit \Sigma}{(1660)}}$ $1/2{}^{+}$ *** ${{\mathit \Sigma}{(1670)}}$ $3/2{}^{-}$ **** ${{\mathit \Sigma}{(1670)}}$ Bumps ${{\mathit \Sigma}{(1690)}}$ Bumps ** ${{\mathit \Sigma}{(1730)}}$ $3/2{}^{+}$ * ${{\mathit \Sigma}{(1750)}}$ $1/2{}^{-}$ *** ${{\mathit \Sigma}{(1770)}}$ $1/2{}^{+}$ * ${{\mathit \Sigma}{(1775)}}$ $5/2{}^{-}$ **** ${{\mathit \Sigma}{(1840)}}$ $3/2{}^{+}$ * ${{\mathit \Sigma}{(1880)}}$ $1/2{}^{+}$ ** ${{\mathit \Sigma}{(1900)}}$ $1/2{}^{-}$ * ${{\mathit \Sigma}{(1915)}}$ $5/2{}^{+}$ **** ${{\mathit \Sigma}{(1940)}}$ $3/2{}^{+}$ * ${{\mathit \Sigma}{(1940)}}$ $3/2{}^{-}$ *** ${{\mathit \Sigma}{(2000)}}$ $1/2{}^{-}$ * ${{\mathit \Sigma}{(2030)}}$ $7/2{}^{+}$ **** ${{\mathit \Sigma}{(2070)}}$ $5/2{}^{+}$ * ${{\mathit \Sigma}{(2080)}}$ $3/2{}^{+}$ ** ${{\mathit \Sigma}{(2100)}}$ $7/2{}^{-}$ * ${{\mathit \Sigma}{(2250)}}$ *** ${{\mathit \Sigma}{(2455)}}$ Bumps ** ${{\mathit \Sigma}{(2620)}}$ Bumps ** ${{\mathit \Sigma}{(3000)}}$ Bumps * ${{\mathit \Sigma}{(3170)}}$ Bumps * | {"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": 0.20122136175632477, "perplexity": 1624.1203213729962}, "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/1508187826114.69/warc/CC-MAIN-20171023145244-20171023165244-00056.warc.gz"} |
http://forum.allaboutcircuits.com/threads/identity-matrix.62172/ | # identity matrix
Discussion in 'Math' started by kokkie_d, Nov 18, 2011.
1. ### kokkie_d Thread Starter Active Member
Jan 12, 2009
72
0
Hi,
I have the following function:
$f(x) = e^{\underline{A}t}*\underline{A}^{-1}*\underline{A}*e^{\underline{A}T-t}$
Where $\underline{A}$ is A matrix.
Am I allowed to simplify $\underline{A}^{-1}*\underline{A}$ to an identity matrix?
I know a matrix times its inverse is an identity matrix but I am worried about the order to do the calculations in and if it then still is allowed.
Cheers
2. ### Georacer Moderator
Nov 25, 2009
5,142
1,266
If your function is exactly as you wrote it, then you can.
The inverse matrix of $A$, $A'$ is defined as:
$A \cdot A'=A' \cdot A=I$
kokkie_d likes this.
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1,847 | {"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": 6, "/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": 0.9160626530647278, "perplexity": 3032.557236721461}, "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/1476988722951.82/warc/CC-MAIN-20161020183842-00196-ip-10-171-6-4.ec2.internal.warc.gz"} |
http://slideplayer.com/slide/794221/ | # Dr Roger Bennett Rm. 23 Xtn. 8559 Lecture 6.
## Presentation on theme: "Dr Roger Bennett Rm. 23 Xtn. 8559 Lecture 6."— Presentation transcript:
Dr Roger Bennett R.A.Bennett@Reading.ac.uk Rm. 23 Xtn. 8559 Lecture 6
Partial Derivatives For functions of several variables z=z(x,y), z is continuous function of independent variables x and y. Here z is called an explicit function. This function can be represented as a surface in Cartesian coordinates.
Partial Derivatives Imagine the surface intersects a planar surface parallel to the z-x plane which cuts the y-axis at y. The gradient of the line of intersection is given by the partial derivative of z with respect to x, and is defined as:-
Partial Derivatives This is the same expression as for normal differentials but with y considered as a constant. It effectively gives the gradient in the x direction. A similar expression can be written for the y direction.
Partial Derivatives - example Let z= x 2 +3xy +y 3
Partial Derivatives - example Ignoring terms second order in the limit x 0
Partial Derivatives Differential form take the implicit function f(x, y, z) = 0, means x, y,and z are related and only two variables are independent so x = x(y,z) Similarly we can write y = y (x,z) and
Partial Derivatives Substituting for dy
Partial Derivatives We can choose x and z to be independent variables so choosing dz = 0 is valid, dx can then be non-zero. Reciprocal relation
Partial Derivatives We can choose x and z to be independent variables so choosing dx = 0 is valid, dz can then be non-zero. Cyclical relation
Partial Derivatives – Chain rule Supposing variables x, y, z, are not independent (so any two variables define the third) we can define the function = (x, y) and re-arrange to x = x(, y). Dividing by dz and hold constant. Chain Rule
Higher Partial Derivatives Repeated application allows the definition of higher derivatives.
Higher Partial Derivatives The order of differentiation does not matter as long as the derivatives are continuous.
Pfaffian forms The differential equation In general the integral depends on the path of integration. In this case this is called an inexact differential. But the integral is path independent if it can be expressed as a single valued function f(x,y,z). df is then an exact differential.
Pfaffian forms – exact differentials If we write It follows from the double differentials that These are necessary and sufficient for the Pfaffian form to be an exact differential.
Dr Roger Bennett R.A.Bennett@Reading.ac.uk Rm. 23 Xtn. 8559 Lecture 7
Processes – functions of state The internal energy U of a system is a function of state. For a fluid (ideal gas) we could write U=U(P,T) or U=U(V,T).
Processes – functions of state The internal energy U of a system is a function of state. For a fluid (ideal gas) we could write U=U(P,T) or U=U(V,T). It is straightforward to imagine that in changing from state 1 to state 2 we can define U 1 and U 2 such that the difference in energies U=U 2 -U 1 is the change of energy of the system.
Processes – functions of state The internal energy U of a system is a function of state. For a fluid (ideal gas) we could write U=U(P,T) or U=U(V,T). It is straightforward to imagine that in changing from state 1 to state 2 we can define U 1 and U 2 such that the difference in energies U=U 2 -U 1 is the change of energy of the system. We cannot make the same argument for Work or Heat as you cannot define a quantity of either to be associated with a state. They are only defined during changes.
Processes – functions of state The internal energy U of a system is a function of state. For a fluid (ideal gas) we could write U=U(P,T) or U=U(V,T). It is straightforward to imagine that in changing from state 1 to state 2 we can define U 1 and U 2 such that the difference in energies U=U 2 -U 1 is the change of energy of the system. We cannot make the same argument for Work or Heat as you cannot define a quantity of either to be associated with a state. They are only defined during changes. Work and heat flow are different forms of energy transfer.
Heat and Work The physical distinction between these two modes of energy transfer is: –Work deals with macroscopically observable degrees of freedom. –Heat is energy transfer on the microscopic scale via internal degrees of freedom of the system.
Heat and Work The physical distinction between these two modes of energy transfer is: –Work deals with macroscopically observable degrees of freedom. –Heat is energy transfer on the microscopic scale via internal degrees of freedom of the system. First Law of Thermodynamics dU = đW + đQ is always true as it is just conservation of energy – you just have to account for all possible heat and work processes.
Work First Law of Thermodynamics dU = đW + đQ is always true as it is just conservation of energy – you just have to account for all possible heat and work processes. –Stretching a wire (spring) đW = Fdx –Surface tension – bubble đW = dA –Charging a capacitor đW = EdZ where E is the emf and Z stored charge.
Analysis of processes Quasistatic work – đW = -PdV P V a b
Analysis of processes Isothermal Work (ideal gas) P V a b
Heat Transfer Constant pressure heating –đQ = dU - đW –đQ = dU + PdV –đQ (đQ/ T) P = C P specific heat capacity at constant pressure. P V a b
Heat Transfer Ideal Gas Only C v = (đQ/ T) v = (dU/ T) v C p = (đQ/ T) p For ideal gas PV = ( -1)U = NRT
Heat Transfer Ideal Gas Only C v = (đQ/ T) v = (dU/ T) v = 3/2 R C p = (đQ/ T) p | {"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": 0.9567172527313232, "perplexity": 737.9652212067059}, "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/1521257647758.97/warc/CC-MAIN-20180322014514-20180322034514-00567.warc.gz"} |
https://www.proofwiki.org/wiki/Definition:Congruence_(Number_Theory)/Historical_Note | # Definition:Congruence (Number Theory)/Historical Note
He originated the notation $a \equiv b \pmod m$ in his work Disquisitiones Arithmeticae, published in $1801$. | {"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": 0.9651008248329163, "perplexity": 10368.996984835434}, "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-2022-27/segments/1656103943339.53/warc/CC-MAIN-20220701155803-20220701185803-00470.warc.gz"} |
https://tex.stackexchange.com/questions/362695/output-plaintext-document-instead-of-dvi-pdf | # Output plaintext document instead of DVI/PDF
Is there a way to get LaTeX to generate a plaintext (ie: .txt file) output instead of a .pdf/.dvi file?
I have some lengthy manuals that I'm writing, and I'm trying to find a way to generate pretty ASCII documents with formatting like so:
########################################################################
########################################################################
========================================================================
========================================================================
........................................................................
........................................................................
Lorem ipsum dolor. Everything here wraps at seventy-two (72) characters so
someone can copy-paste into a Linux mail client, like neomutt or pine.
Multi-line code snippet that is indented via
a hard-tab.
Isn't
that
cool?
Aaaaaaaaand....
Here's a really long code snippet that's allowed to extend past the 72-character margin.
More text.
I'm opting to go with LaTeX because I'm familiar with it, and the documents will have a lot of internal references to sections, ASCII-art figures, etc, and some of these manuals are huge (200+ pages).
Thank you.
• If you have such a significant number of internal references and figures, why not take advantage of the full features available via LaTeX and assorted packages and just have your manuals be PDF? I find text-only readmes to be easy to use only when they're relatively short. If you're planning on terminal-focused text, look into how manpages and info files are formatted (which also provide some degree of hypertext/advanced browsing). You may also find Markdown useful. – JAB Apr 7 '17 at 22:57
If I take the standard latex example document sample2e.tex (which should be in your tex input path already) and run latex sample2e to get a DVI file then dvi2tty sample2e produces
An Example Document
Leslie Lamport
January 21, 1994
This is an example input file. Comparing it with the output it generates can
show you how to produce a simple document of your own.
1 Ordinary Text
The ends of words and sentences are marked by spaces. It doesn't matter how
many spaces you type; one is as good as 100. The end of a line counts as a
space.
One or more blank lines denote the end of a paragraph.
Since any number of consecutive spaces are treated like a single one, the fo*
*r-
matting of the input file makes no difference to LATEX, but it makes a differen*
*ce
to you. When you use LATEX, making your input file as easy to read as possible
will be a great help as you write your document and when you change it. This
Because printing is different from typewriting, there are a number of things
that you have to do differently when preparing an input file than if you were j*
*ust
typing the document directly. Quotation marks like "this" have to be handled
specially, as do quotes within quotes: " this' is what I just wrote, not that*
*' ".
Dashes come in three sizes: an intra-word dash, a medium dash for number
ranges like 1--2, and a punctuation dash---like this.
A sentence-ending space should be larger than the space between words
within a sentence. You sometimes have to type special commands in conjunc-
tion with punctuation characters to get this right, as in the following sentenc*
*e.
Gnats, gnus, etc. all begin with G. You should check the spaces after periods
when reading your output to make sure you haven't forgotten any special cases.
Generating an ellipsis . . . with the right spacing around the periods requires*
* a
special command.
LATEX interprets some common characters as commands, so you must type
special commands to generate them. These characters include the following: \$
& % # { and }.
In printing, text is usually emphasized with an italic type style.
A long segment of text can also be emphasized in this way. Text within such
a segment can be given additional emphasis.
1
It is sometimes necessary to prevent LATEX from breaking a line where it
might otherwise do so. This may be at a space, as between the "Mr." and
"Jones" in "Mr. Jones", or within a word---especially when the word is a symbol
like itemnum that makes little sense when hyphenated across lines.
Footnotes1 pose no problem.
LATEX is good at typesetting mathematicalPformulas like x - 3y + z = 7 or
a1 > x2n + y2n > x# or (A, B) = iaibi. The spaces you type in a formula
are ignored. Remember that a letter like x is a formula when it denotes a
mathematical symbol, and it should be typed as one.
2 Displayed Text
Text is displayed by indenting it from the left margin. Quotations are commonly
displayed. There are short quotations
This is a short quotation. It consists of a single paragraph of text.
See how it is formatted.
and longer ones.
This is a longer quotation. It consists of two paragraphs of text,
neither of which are particularly interesting.
This is the second paragraph of the quotation. It is just as dull
as the first paragraph.
Another frequently-displayed structure is a list. The following is an example of
an itemized list.
o This is the first item of an itemized list. Each item in the list is marked
with a "tick". You don't have to worry about what kind of tick mark is
used.
o This is the second item of the list. It contains another list nested inside
it. The inner list is an enumerated list.
1. This is the first item of an enumerated list that is nested within the
itemized list.
2. This is the second item of the inner list. LATEX allows you to nest
lists deeper than you really should.
This is the rest of the second item of the outer list. It is no more inter*
*esting
than any other part of the item.
o This is the third item of the list.
You can even display poetry.
____________________________1
This is an example of a footnote.
2
There is an environment for verse
Whose features some poets will curse.
Them do all line breaking,
It allows them to put too many words on a line when they'd rather
be forced to be terse.
Mathematical formulas may also be displayed. A displayed formula is one-
line long; multiline formulas require special formatting instructions.
(#, ##) = x##+ y2 + zni
Don't start a paragraph with a displayed equation, nor make one a paragraph
by itself.
3
being a reasonable approximation to the pdflatex output of | {"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": 0.8807303309440613, "perplexity": 2078.477373028695}, "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-2020-24/segments/1590347413901.34/warc/CC-MAIN-20200601005011-20200601035011-00019.warc.gz"} |
https://stupidsid.com/previous-question-papers/download/engineering-mathematics-3-16410 | MORE IN Engineering Mathematics 3
VTU Computer Science (Semester 3)
Engineering Mathematics 3
June 2015
Total marks: --
Total time: --
INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary
1 (a) Expand f(x)=x sin x as a Fourier series in the interval (-π.π), Hence deduce the following
i)$\dfrac{\pi}{2}=1+\dfrac{2}{1.3}-\dfrac{2}{3.5}+\dfrac{2}{5.7}$
ii}$\dfrac{\pi-2}{4}=\dfrac{1}{1.3}-\dfrac{1}{3.5}+\dfrac{1}{5.7}-+....$
7 M
1 (b) Find the half-range Fourier cosine series for the function
$f(x)=\left\{\begin{matrix} kx, &0\leq x\leq l/2 \\k(l-x,) &l/2 where k is non-interger positive constant 6 M 1 (c) Find the constant term and the first two harmonics in the Fourier series for f(x) given by the following table. X: 0 π/3 2 π3 π 4π/3 5 π/3 2 π F(x): 1 1.4 1.9 1.7 1.5 1.2 0 7 M 2 (a) Find the Fourier transform of the function f(x)=xe-2x 7 M 2 (b) Find the Fourier sine transforms of the Functions \[f(x)\left\{\begin{matrix} Sin x, &0 6 M 2 (c) Find the inverse Fourier sine Transform of \[F(\alpha)=\dfrac{1}{\alpha}e^{-3 \alpha} a>0$
7 M
3 (a) Find the various possible solution of one dimensional wave equation $\dfrac{\partial^2 u}{\partial x^2}=C^2\dfrac{\partial^2 u}{\partial x^2}$ by separable variable method
7 M
3 (b) Obtain solution of heat equation $\dfrac{\partial^2u }{\partial x^2}+\dfrac{\partial^2u }{\partial y^2}=0 \ subject\ to \ condition\ u(0,y)=u(l,y)=0,u(x,0)=0,u(x,s)=\sin \left ( \dfrac{\pi x}{l} \right )$
7 M
4 (a) The pressure P and Volume V of gas are related by the equation PVr = K, where r and k are constant. Fit this equation to the following set of observation (in appropriate units)
P: 0.5 1 1.5 2 2.5 3 V: 1.62 1 0.75 0.62 0.52 0.46
7 M
4 (b) Solve the following LPP by using the Graphical method:
Maximize: Z=3x1+4x2
Under the Constraints 4x1+2x2≤80
2x1 +5x2≤ 180
x1, x2≥0
6 M
4 (c) Solve the following using simple method
Maximize : Z=2x+4y, subject to the
constraint : 3x+y≤2z, 2x+3y ≤24, x≥0,y≥0
7 M
5 (a) Using Regular- Falsi method, find a real root (correct to three decimal places) of the equation cos x=3x-1 that lies between 0.5 and 1 (Here,x in radians)
7 M
5 (c) Using the power method find the largest energy value corresponding Eigen vectors of the matrix
$\begin{bmatrix} 6 &-2 &2 \\-2 &3 &-1 \\2 &-1 &3 \end{bmatrix}$
taking [1,1,1,]Tas the initial Eigen vectors perform 5 iterations.
7 M
6 (a) From the data given in the following Table; find the number of student who obtained
i) Less than 45 marks ii) Between 40 and 45 marks
Marks 30-40 40-50 50-60 60-70 70-80 No. of Students 31 42 51 35 31
7 M
6 (b) Using the Lagrange's formula, find the interpolating polynomial that approximates to the function described by the following table
X 0 1 2 3 4 f(x) 3 6 11 18 27
Hence find f(0.5) and (3.1)
6 M
6 (c) Evaluate $\int_{0}^{1}\limits \dfrac{x}{1+x^2}dx$ by using Simpson's (3/8)th Rule, dividing interval into 3 equal parts Hence find an approximate value of log &sqrt;2.
7 M
7 (a) Solve the one-dimensional wave equation $\dfrac{\partial^2u }{\partial x^2}=\dfrac{\partial^2u }{\partial t^2}$
subject to the boundary conditions u(0,t)=0, u(1,t)=0,t≥0 and the initial conditions $u(x,0)=\sin \pix,\dfrac{\partial t}{\partial t}(x,0)=0 7 M 7 (b) Consider the heat equation \[2\dfrac{\partial^2 u}{\partial x^2}=\dfrac{\partial u}{\partial t}$ under the following conditions:
i) u(0,t)=u(4,t)=0,t≥0
ii) u(x,0)=x(4-x),0 Employ the Bender-Schmidt method with h=1 to find the solution of the equation for 0
6 M
7 (c) Solve the two-dimensional Laplace equation $\dfrac{\partial^2 u}{\partial x^2}=\dfrac{\partial^2 u}{\partial y^2}=0$ at the interior pivotal point of the square region shown in the following figure. The values of u at the pivotal points on the boundary are also shown in the figure
7 M
8 (a) State and prove the recurrence relation of Z-Transformation hence find ZT (nP) and $Z_{r}\left [\cos h\left ( \dfrac{n \pi}{2}+0 \right ) \right ]$
7 M
8 (b) Find $Z_{T}^{-1}\left [ \dfrac {z^3-20z}{(z-2)^3 (z-4)} \right ]$
6 M
8 (c) Solve the difference equation
yn+2 -2y n+1 -3yn=3n+2n
Given y0=y1=0
7 M
More question papers from Engineering Mathematics 3 | {"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": 0.942406952381134, "perplexity": 1847.264277621849}, "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/1573496670731.88/warc/CC-MAIN-20191121050543-20191121074543-00494.warc.gz"} |
http://clay6.com/qa/18115/the-radius-of-gyration-of-a-solid-sphere-of-radius-r-about-a-certain-axes-i | Comment
Share
Q)
# The radius of gyration of a solid sphere of radius R about a certain axes is also equal to R. If r is the distance between the axes and the centre of a sphere , then r is equal to
$\begin {array} {1 1} (1)\;R & \quad (2)\;0.5 R \\ (3)\;\sqrt { 0.6}R & \quad (4)\;Zero \end {array}$
$\sqrt{0.6}R$ | {"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": 0.7901807427406311, "perplexity": 113.64739463242357}, "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-2019-51/segments/1575540553486.23/warc/CC-MAIN-20191213094833-20191213122833-00445.warc.gz"} |
https://docs.omniverse.nvidia.com/app_isaacsim/app_isaacsim/ext_semantic_schema_editor.html | # Semantic Schema Editor¶
The functioning of segmentation and bounding box sensor data relies a lot on the semantic meaning of different objects in the simulation environment. The Semantic Schema Editor tool allows user to assign semantic labels to those objects.
Go to Synthetic Data->Semantic Schema Editor to enable it. There are two ways to assign semantic labels to objects.
Apply semantic data on selected objects
As the title suggests, select a group of objects and then for each object, we specify the Type field as class and the Data field as the semantic label.
Apply semantic data on entire stage
We use a heuristic based approach to assign semantic labels to different objects in the scene on pressing Generate Labels button. The field Prim types to label specifies which USD object type will be assigned a semantic label. The field Class list specifies a list of class names. If an object in the scene contains any of these class names, then its semantic label will be assigned to that class name.
## Semantic Schema Editor Usage Example¶
Load the simple room stage from here - Isaac/Environments/Simple_Room/simple_room.usd
This stage doesn’t come with any pre-loaded semantic information. We can verify this using the Synthetic Data Visualizer tool. For both scenarios below, click on icon in the Viewport window, check RGB and Semantic Segmentation sensors and press Visualize. This will show output from both sensors. The Semantic Segmentation output is red (represents background class) which signifies that the assets don’t contain semantic information.
Apply semantic data on selected objects
After enabling the Semantic Schema Editor extension, select the table (prim location is /Root/table_low_327/table_low and prim type is Mesh) and then in Semantic Schema Editor UI, specify the Type field as class and the Data field as table. This will apply semantic label to the table asset. We can verify using two approaches.
1. Use the Visualize Synthetic Data tool, check RGB and Semantic Segmentation sensors and press Visualize. The Semantic Segmentation output is red except the table section of the image which is orange in color.
2. Select /Root/table_low_327/table_low prim and go to Details tab. The attributes semantic:Semantics:params:semanticData and semantic:Semantics:params:semanticType will be set to table and class respectively.
Apply semantic data on entire stage
After enabling the Semantic Schema Editor extension, specify the Prim types to label field as Mesh, the Class list field as table,floor,wall and press Generate Labels. For all assets in the scene, it will check if the path of an asset of type Mesh contains any of the class names specified in the Class list field and then its semantic label will be assigned to that class name. We can verify using two approaches.
1. Use the Visualize Synthetic Data tool, check RGB and Semantic Segmentation sensors and press Visualize. The Semantic Segmentation output will show different colors corresponding to different classes.
2. We can also check attributes for some of the assets. For example, select /Root/table_low_327/table_low prim and go to Details tab. The attributes semantic:Semantics:params:semanticData and semantic:Semantics:params:semanticType will be set to table and class respectively. Similarly, select /Root/Towel_Room01_floor_bottom_218/Towel_Room01_floor_bottom prim and go to Details tab. The attributes semantic:Semantics:params:semanticData and semantic:Semantics:params:semanticType will be set to floor and class respectively. | {"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": 0.17728757858276367, "perplexity": 3118.863910174896}, "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/1634323585653.49/warc/CC-MAIN-20211023064718-20211023094718-00173.warc.gz"} |
https://www.physicsforums.com/threads/testing-the-field-strength-of-a-permanent-bar-magnet.518875/ | # Testing the field strength of a permanent bar magnet
1. Aug 3, 2011
### AUS_Chris
Hi,
I've just completed a prac, where a beam was placed into a solenoid with a current flowing through it, causing a force to exerted down and I balanced out the force by placing weights on the other end in the effort of calculating the magnetic field strength. Anyway, one of the short answer questions given states:
"Could this apparatus be used to find the field strength of a small permanent bar magnet? Discuss the process and describe the limitations."
The relevant equation used to calculate the magnetic field strength was: B = mg/IL. However, this problems is largely theory based.
I assume that if a permanent bar magnet was placed within a solenoid which had current flowing through it, that the magnetic field lines would interfere with another and cause the direction of the force caused by the magnetic field on the perpendicular section of the magnet to the field lines (according to the Right Hand Slap Rule) to not act directly downwards so that I could counteract it by placing weights on the other end of the magnet, but I'm clearly finding difficulty.
Thanks for reading, and I would greatly appreciate help. (NOTE: I apologize if this in the wrong section of the forum, this is my first post)
2. Aug 3, 2011
### PeterO
I think the suggestion was "can you use a similar set-up using a small permanent magnet instead of the solenoid with a fixed current" | {"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": 0.8911672830581665, "perplexity": 537.1242381548234}, "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-2017-51/segments/1512948550986.47/warc/CC-MAIN-20171214202730-20171214222730-00188.warc.gz"} |
https://www.acmicpc.net/problem/16871 | 시간 제한 메모리 제한 제출 정답 맞은 사람 정답 비율
2 초 512 MB 0 0 0 0.000%
## 문제
Generating a random number sequence is not easy. Many sequences may look random but upon closer inspection we can find hidden regularities in the occurrence of the numbers. For example, consider the following 100-digit “random” sequence starting with 4 7 9... :
4 7 9 5 9 3 5 0 0 1 7 8 5 0 2 6 3 5 4 4
4 6 3 3 2 7 1 8 7 8 7 6 1 1 7 2 5 4 7 2
0 4 4 5 8 3 0 6 9 3 2 6 6 8 5 2 5 1 2 7
2 4 1 0 0 4 9 1 8 7 5 0 4 4 8 4 3 2 6 8
8 5 6 7 0 9 7 0 3 6 1 4 4 1 2 3 2 6 9 9
If you look closely, whenever a 4 is followed immediately by another 4, the third value after this will be a 3 (we’re sure you saw that). We’ll call features like this triple correlations and we’ll represent it as 4(1)4(3)3, where the numbers in parentheses indicate how far away each number on either side of the parentheses must be. More precisely, a sequence of p digits has an a(n)b(m)c triple correlation if
1. any time there is an a followed n locations later by a b there is always a c located m locations after the b unless b’s location is within distance m − 1 of the end of the sequence.
2. any time there is a b followed m locations later by a c there is always an a located n locations before the b unless b’s location is within distance n − 1 of the beginning of the sequence.
3. any time there is an a followed n + m locations later by a c there is always a b located n locations after the a.
4. the correlation occurs at least dp/40e + 1 times, where dxe denotes the smallest integer greater than or equal to x.
Such correlations are tough to spot in general, so that’s where we need your help. You will be given a sequence of digits and must search it for triple correlations.
## 입력
Input starts with a positive integer p (p ≤ 1 000) indicating the number of random digits in the sequence. Starting on the next line will be the p digits, separated by spaces and potentially spread across multiple lines. No line will contain more than 100 digits and there will be no blank lines.
## 출력
Display triple correlation a(n)b(m)c found if it occurs in the list (with the appropriate values for a, b, c, n, and m filled in) or the phrase random sequence otherwise. If there are multiple triple correlations in the sequence, display the one which has its first occurrence (as determined by the first occurrence of its a-value) earliest in the sequence. If there is still a tie, choose the one with the smaller value of n, and if there is still a tie, choose the one with the smaller value of m.
## 예제 입력 1
100
4 7 9 5 9 3 5 0 0 1 7 8 5 0 2 6 3 5 4 4
4 6 3 3 2 7 1 8 7 8 7 6 1 1 7 2 5 4 7 2
0 4 4 5 8 3 0 6 9 3 2 6 6 8 5 2 5 1 2 7
2 4 1 0 0 4 9 1 8 7 5 0 4 4 8 4 3 2 6 8
8 5 6 7 0 9 7 0 3 6 1 4 4 1 2 3 2 6 9 9
## 예제 출력 1
triple correlation 4(1)4(3)3 found
## 예제 입력 2
10
1 2 3 1 2 2 1 1 3 0
## 예제 출력 2
random sequence | {"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": 0.33257797360420227, "perplexity": 150.7392179237986}, "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/1560627998325.55/warc/CC-MAIN-20190616222856-20190617004856-00382.warc.gz"} |
https://www.matrixmillenium.com.br/8mr54f6/lxp.php?ezb=parabolic-antenna-beamwidth-calculator | All that is needed is a knowledge of the satellite position (sometimes just the satellite is needed as its coordinates may be held within the calculator), the position of the receiver in latitude and longitude. Our parabolic antennas are perfectly suited for high density point-to-point client-premises or backhaul applications. This 15dBi WiFi antenna is a powerful booster parabolic antenna that works best for point to point applications over a long distance. These antennas are available in the 1. See our other Electronics Calculators. Top-quality components and durable cast-aluminium design allows the radio link to be used in very difficult climatic conditions. Parabolic antenna focal length. Also, the interest in. Should I be receiving anything or is the problem my antennas shitty positioning?. Directivity is a measure of the concentration of radiation in the direction of the maximum. Its shape is part of a circular paraboloid, that is, the surface generated by a parabola revolving around its axis. beamwidth [edit ] radiation is a parameter, linked to the radiation pattern. 1dBi 10-12 GHz products in our Wireless: Antennas Category for even more options. The gain is one of the key factors associated with the parabolic reflector antenna. Alphabetical order wise antenna formulas / equations are listed here. Use our free online app Parabolic Dish Antenna Calculator to determine all important calculations with parameters and constants. The calculation results are:. Antenna 3db Beamwidth Calculator. It is the study and analysis of nature and universe. Site shielding. By using 26 GHz the size of the parabolic antenna has been re-duced to fit an 8” tank opening. You can use any of the input arguments from previous syntaxes. 22: Antenna Arrays. Use our free online app Antenna and Waveguide Calculators to determine all important calculations with parameters and constants. Antenna Gain and Beamwidth: Two of the most basic specifications for small satellite antennas are the antenna gain and beamwidth. Abstract: No abstract text available Text: System s Using Air-Dielectric H ELIA X ® Coaxial Cable Andrew offers terrestrial microwave antenna systems from 335 MHz to 3. 15 dBi, a horizontal beam width of 360 deg and a vertical beam width of 45 deg. com: wi-fi antennas. The radiation pattern is a graphical depiction of the relative field strength transmitted from or received by the antenna. 5GHz, WiFi at 2. This can be reasoned by thinking of the available transmit power. This calculator determines the theoretical maximum range of a radar based on the radar transmitted power, antenna gain or aperture, frequency, radar cross-sectional area of the target and the sensitivity of the radar receiver. Antenna gain increases respectively with each decrease in beamwidth. Conversions are more critical at these frequencies. Parabolic Antenna Tilt (Degrees): Tilt (a -> b) = 57. A parabolic antenna has a diameter of 3 meters, an efficiency of 60%, and operates at a frequency of 4 GHz. Obviously, the azimuth of the antenna must match the azimuth of the satellite, or it will not acquire the satellite. Type 120 Ku-Band Receive Only Antenna System. The new generation is coming in a deep reflector dish design with a massive holder. 5GHz, WiFi at 2. 99 ) Convenient graphical calculator that determines the Gain and Beamwidth of a parabolic reflector. This figure determines the azimuthal resolution of the radar system. panel antennas, mobile GPS and cellular antennas, as well as base station antennas (for cell phone towers), through its Wireless Communications Solutions Division. 313in/440mm) LPDA Directional Antenna. The above formula is to calculate the gain of a parabolic dish antenna where: D = The Diameter of the Dish. We have considered diameter of the dish 1900 mm and f/D ratio 0,4. This is measured in decibels (dB). The radiation pattern in Figure below shows that the main lobe for 23 cm band has beam width about 130 degress and for 6 cm - about 110 degress. 92mm is the optimal diameter if you want to try to optimize it for flattest response across Channels 1-11 this is because it minimizes the difference in the probe position between Channels 1-11 about 2. The "gain" of a radar antenna is a measure of its concentrated energy (in the beam) relative to the energy which would impinge upon a target if the same transmitted energy was emitted by an isotropic antenna. Prime focus parabolic dish focus, gain and beamwidth calculator for HP41C. If using an antenna (Discussed next) omnidirectional with the addition of 10-12 dB, we get a coverage area of 4-5 km. Discover the best Satellite Dishes in Best Sellers. and it weighs around 4. Description: Waveguide parabolic antenna with radome - This series biconical antennas is a vertically polarized wideband omnidirectional antenna; the antenna has a frequency band, VSWR, stable performance, solid structure, light weight, ease of installation and other characteristics; suitable for floor, roof , car, ship FM radio admission. Helical antennas invented by John Kraus give a circular polarized wave. 725 GHz to 5. exceptionally good for tuning in on distant wifi hotspots and rejecting signals from unwanted stations that cause signal degradation and loss of connection speed. The above formula is to calculate the gain of a parabolic dish antenna where: D = The Diameter of the Dish. A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves. The Antenna Downtilt and Coverage Calculator (aka Antenna Tilt Angle Calculator) is used to determine the approximate downward angle, measured in degrees, which the transmitting antenna is to be positioned for optimal signal strength and coverage. Antenna beamwidth calculator. , width of 16 in. 3 Beam solid angle and beamwidth of a highly directive antenna. This effect can also be exploited to achieve an electronic pivoting of the antenna beam as a function of change of the transmission frequency. This concept can eliminate all the headaches of a gimbal in a radar system. Multi-Point Applications (Omnidirectional antenna; elevation patterns for 7 dBi and 12 dBi omni antennas. θ (degrees) = 70•λ / D θ (radians) = λ / D where, D - dish diameter, λ - wavelength, θ - antenna beamwidth. Two-Dimensional Aperture Antennas The field pattern of a two-dimensional aperture. Calculate the following: I. *This for satellite ground antennas located near to other antennas or sources of power in the same frequency band as the satellite link. But Hi-VHF SWR (75-ohms) is Very EXCESSIVE. This concept can eliminate all the headaches of a gimbal in a radar system. Typically only a few minutes. This example will be for a parabolic dish reflector with the diameter of the dish D equal to 11 wavelengths. Here is a useful "cheat sheet" converting VSWR to the percentage of reflected power. As discussed under S-band, the Ku-band system's narrow beam makes it difficult for TDRS antennas to lock on to the signal. It is the study and analysis of nature and universe. A cutoff frequency is a border in a system's frequency response at which energy flowing through the system starts to decrease or reflected without being transmitted. Turmode WAG58293 5. this case captured by an antenna. ThisHana 27dBi Parabolic Directional Grid Dish Antenna is perfect for long-range wireless data transmissions for 5 GHz wireless devices. Outdoor antenna for wireless/WiFi network. Correcting VSAT dish distortion. 8GHz Grid Parabolic Outdoor Antenna. As discussed under S-band, the Ku-band system's narrow beam makes it difficult for TDRS antennas to lock on to the signal. Recall John’s talk – trade-off between gain and beam width. pattern(___,Name,Value) uses additional options specified by one or more Name, Value pair arguments. The above is a "relative gain" test, where you are measuring the "directivity of the parabolic antenna. aiming high gain yagi antennas correctly is very important. Outdoor antenna for wireless/WiFi network. The feed antenna is positioned so. By using 26 GHz the size of the parabolic antenna has been re-duced to fit an 8” tank opening. You will want to check the antenna's specifications. KA1GT Troposcatter and Link Budget Calculator. 825 GHz 90 Deg. 92mm, N and SMA connectors, or just a square flange. A 160-ft-diameter parabolic antenna is driven by a 10-W transmitter at 4. Calculate the following: I. Reflector antenna radiation patterns are determined by a number of factors, but the most important ones are the radiation pattern of the feed antenna and the shape of the reflector. CHANNEL MASTER 4251 REFERENCE ANTENNA: This site is to report the results of continuing field tests using different types of antennas, comparing them to my reference antenna, the Channel Master 4251, a 7-ft. This calculator determines the theoretical maximum range of a radar based on the radar transmitted power, antenna gain or aperture, frequency, radar cross-sectional area of the target and the sensitivity of the radar receiver. The method we used to show that the field pattern of a one-dimensional aperture is the one-dimensional Fourier transform of the aperture field illumination can simply be generalized to the more realistic case of a two-dimensional aperture:. Parabolic Grid antennas are great as they handle inclement weather much better in permanant installations (wind passes right through them) but are expensive because of the fact that they're designed for this. 0 m | 10 ft High Performance Parabolic Shielded Antenna, single-polarized, 7. This page of converters and calculators section covers Parabolic Antenna calculator. Ubiquiti Networks AF-5G34-S45 is designed for use with airFiber 5X radios. 437Ghz), as they have 11 channels). That is used for both rec eption and transmission purpose. This concept can eliminate all the headaches of a gimbal in a radar system. Rozendal Associates, Inc. The half power beamwidth of the radiation pattern gets narrower with increasing frequency. 4 GHz parabolic antenna. Hi, I was wondering if anyone knew how to calculate the HPBW (Half Power Beam Width) of a half wavelength, one wavelength, and 3/2 wavelength dipole? Or is there any code for this that can be done. Directional1 Di ti l - this type of antenna has a narrow beamwidth; with the power being more directional, greater distances are usually directional achieved but area coverage is sacrificed - Yagi Panel, Sector and Parabolic antennae Yagi, Panel - an EUM, NCL Station/Master will use this type of antenna p in both Point to Point and Point to. The total length, as well as the spacing between turns of the helix, determines its beam width. The beamwidth of the antenna is often needed as it will enable the time of the satellite solar outage to be determined. Horn Antenna Calculator Converters And CalculatorsParabolic Antenna Calculator Dish2 6 Antenna Beamwidth And Sidelobe PerformanceAntenna Beam Width Calculation New Images2 6 Antenna Beamwidth And Sidelobe PerformanceAntenna Basic S Pulse ElectronicsElectronic …. the parabolic reflector; a feed antenna at the reflector's focus; The feed antenna is commonly a horn antenna, which can have a relatively wide bandwidth, depending on the particular design. Gain of Directional Antennas Gain is an antenna property dealing with an antenna's ability to direct its radiated power in a desired direction, or synonymously, to receive energy preferentially from a desired direction. 6 m | 2 ft High Performance Parabolic Reflector Antenna, Single-polarized, 5. Our Broadband parabolic reflector antennas offer high gain and narrow beamwidth for broadband and extremely broadband applications. 4 GHz parabolic antenna was an interesting project idea since it has an interesting shape in addition to its electrical engineering aspects. The most common form is shaped like a dish and is popularly called a dish antenna or parabolic dish. Antenna is nothing but a transducer that radiates the electrical power fed to it in the. With the reflector's narrow beamwidth, this factor became non-negligible fairly quickly and it eventually ceased to perform. greater efficiency of antennas aperture effective area should be more. In the primary radar unit RRP-117. You’re asking the wrong question. The parabolic reflector antenna theory also shows the emanating beam will tend to be parallel. Parabolic Antenna An antenna consisting of a parabolic reflector and a radiating or receiving element at or near its focus. Satellite link budget calculator. Parabolic dish antenna for 5GHz, 30dBi gain. Calculate its effective radiated power (ERP) and its beamwidth. Bi-Directional Hi-VHF Gain = 2. Recall John’s talk – trade-off between gain and beam width. Parabolic Dish Antenna Beamwidth Calculator. The OP is looking for a narrow beamwidth, how narrow is not specified. A high-gain antenna (HGA) is a directional antenna with a focused, narrow radiowave beam width, permitting more precise targeting of the radio signals. Mi-Waves can help you create custom designed antennas for any application. 5º pitch and a ground plane of 0. Antenna gain increases respectively with each decrease in beamwidth. Gain horn antennas are available with 2. Combine a homemade Tripod How To Make Wifi Antennas thought I would To make life easy on you, here's a calculator to Do-It-Yourself Wireless Antennas Update and Resource Center Can Antenna Parabolic Antenna Reflector Omnidirectional. this case captured by an antenna. Find the top 100 most popular items in Amazon Electronics Best Sellers. Home › Science › Antenna. Point to point/ Multi point wireless Network. Beamwidth is an important antenna parameter. However the narrower the beamwidth, the larger the antenna. How to Calculate Antenna 3db Beamwidth - Definition, Formula and Example Definition: Antenna 3dB Beam width is the angle between the half-power of an antenna pattern or beam over which the relative power is at or above 50% of the peak power. We found it provided a longer range signal than similar gain Yagi type antennas because has a narrower beam width (16 degrees horizontal/21 degrees vertical). Parabolic Antenna Design Formulas • focal length of a parabolic reflector D is the diameter f = D2 16d d is the depth f is the focal length • equation of a parabola y=ax2 where a= 1 4 f • f/D given the beamwidth of an antenna feed f D = 1 4tan /4 θ is the beamwidth • length of a parabolic segment. Our team of engineers will work with you on developing and testing your antenna design and manufacturing needs. 6GHz as well as support for AWS band 1700/2100MHz. Beamwidth is 6deg (29dBi) and 4deg (32dBi) and Front to Back ratio is better than 25dB (29dBi) and 38dB (32dBi). 2m diameter and transmits at 14 - 14. 92mm is the optimal diameter if you want to try to optimize it for flattest response across Channels 1-11 this is because it minimizes the difference in the probe position between Channels 1-11 about 2. Suncheck Subtest 2 calibrates Antenna Gain, which encompasses the gain of the antenna dish and microwave losses. Beamwidth is 6deg (29dBi) and 4deg (32dBi) and Front to Back ratio is better than 25dB (29dBi) and 38dB (32dBi). VSAT antenna anti-icing. I understand that theoretically a half wavelength dipole should be about 78 degrees, but how would I prove it with calculations using Matlab? Thanks!. The beamwidth is the angular separation at which the magnitude of the directivity pattern decreases by a certain value from the peak of the main beam. Our state of the art anechoic chamber is used for all our antenna tests during the manufacturing process. 5 degrees from boresight. However, gain is not a quantity which can be defined in terms of physical quantities such as the Watt, ohm or joule,. A-Y3-6 UHF 400-520MHz 6 Element Yagi Antenna. Beware of misprints! ICTP-ITU-URSI School on Wireless Networking for Development The Abdus Salam International Centre for Theoretical Physics ICTP, Trieste (Italy), 5 to 24 February 2007. 706 x D Lo. 48 KB File Type Create Date July 16, 2019 Last Updated July 28, 2019 Download. Antenna beamwidth calculator Enter the diameter of your parabolic dish in m metres and the operating frequency in GHz Gigahertz: Antenna EiRP Estimator, KD4CGA Power from Rig Watts, Frequency MHz, Coax Type, Coax Length Metres, Antenna Type: Antenna matching calculations, WB5CXC Calculates the network to match a line to a specific complex load. Our team of engineers will work with you on developing and testing your antenna design and manufacturing needs. My experience with the I0JXX 25 el 70 cm antenna Do's and Dont's for very weak signal communication. This figure determines the azimuthal resolution of the radar system. This antenna is often built of printed circuit board material and the substrate makes up the patch antenna’s dielectric. Wireless link calculator; Dual-polarization 5Ghz 15dBi 120 degree beamwidth antenna with two RP-SMA connectors. The width of the main lobe (or main beam) spanning a -3dB difference in gain. Parabolic antenna JRMB-1200-10/11 - Antennas for 10/11 GHz - Jirous. If you have a parabola in 3-D, i. Math Calculators. Antenna JRMD-400-10/11 is designed for microwave links at the frequency band 10 and 11 GHz. Yes, helical antennas do have a fairly wide beam width which is why they are popular since a tracker is usually not necessary. 5°, 7°, 10°, 13°, and 16°. a Paraboloid the principle remains the same, but with more complex math. A Modified Parabolic-Cylindrical Reflectarray Antenna for Wide Beam Scanning Capablility Fang Guo 1, Yilin Mao 2, Shenheng Xu 1, Fan Yang 1,2, Atef. net Antenna beamwidth calculator. That is used for both rec eption and transmission purpose. Somebody made a further approximation of 41250->31000, but you cannot use it as an exact number, and depends of your antenna configuration, I mean it is not the same a circular aperture, where you can assume Teta=Phi, and a linear array, where the orthogonal beamwidth is much wider than the along-array beamwidth. You can set the beam width at -3 dB, which is the angular range in which the radiated power density is equal to half the maximum. Antenna with a 20 degree beamwidth has a 20 dB gain. For some applications, the beamwidth at power levels other than 3 dB down is useful. The radiation pattern is relatively narrow for a simple antenna, which makes patch antennas desirable for assembly. 8 dBi FORWARD and 2. Gain of an isotr opic antenna radiating in a uniform spherical pattern is one (0 dB). 825 GHz 90 Deg. Procedure to locate Es'Hail satellite and adjust parabolic antenna in the correct AZ / EL? in this calculators. If working correctly, beamwidth will be about 5-8 degrees which is difficult to aim. The antenna gain formula () applies to the main axis of main lobe of the antenna. Antennas Interface With Space. Harrington 2 (June 29, 1959) A theoretical analysis is made of the effect of antenna size on parameters such as gain, bandwidth, and efficiency. 4 GHz Wifi antennas that is about 2. ThisHana 19dBi Parabolic Directional Grid Dish Antenna is perfect for long-range wireless data transmissions for 2. Multiple patterns can be superimposed on a single graph for comparison. By using 10 GHz and a large parabolic antenna the gauge has a good sensitivity (signal to noise ratio) and a narrow beam width of ±3°, making the gauge suitable to measure in deep tanks up to 40 meters. Outdoor antenna for wireless/WiFi network. VSAT information. Useful converters and calculators. Experience shows that high gain antennas are bigger than low gain ones. A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves. 5-degree beamwidth. Parabolic antenna JRC-24DD MIMO - Antennas for 5/6 GHz parabolic - Jirous. 2 dBi to REAR is slightly HIGHER. My experience with the I0JXX 25 el 70 cm antenna Do's and Dont's for very weak signal communication. IEEE New Hampshire Section Radar Systems Course 1 Antennas Part 1 1/1/2010 IEEE AES Society Radar Systems Engineering Lecture 8 Antennas Part 1 - Basics and Mechanical Scanning Dr. By using 10 GHz and a large parabolic antenna the gauge has a good sensitivity (signal to noise ratio) and a narrow beam width of ±3°, making the gauge suitable to measure in deep tanks up to 40 meters. The overhead cone reflector may need to be made bigger, depending on the beamwidth of the parabolic section. Antenna is nothing but a transducer that radiates the electrical power fed to it in the. Parabolic calculator Cantenna Biquad Trig calculator Quad calculator Video Tutorials Passive Repeater MagicJack MJ Panasonic Fix Curtain Quad 148GTL-D Mods Ham-Radios Hand held Base Cordless-Phones Long range EnGenius Wifi Products High Power Pci Cards USB with antenna Wifi Antennas Pigtails & Coax Yagi Antennas USB Extenders More Routers. Gain of an antenna (in a given direction) is defined as “the ratio of the intensity, in a given direction, to the radiation intensity that would be obtaine. 20 dBd of gain (68 elements on a 171' boom) gives 11 degrees of half-power beamwidth, so you probably want something less than. The half power beamwidth is the angular range of the antenna pattern in which at least half of the maximum power is still radiated! Boundary points of the main lobe are thus the points at which the field strength in the room has decreased by 3 dB with respect to the maximum field strength. knowledge to properly design and optimize parabolic dish antenna configurations for their associated “low-noise” communication stations. The antenna gives good impedance matching over a wide bandwidth of 9 GHz, from 2 GHz to 11 GHz, and good radiation patterns. The antenna equations which follow relate to Figure 1 as a typical antenna. Wi-Fi Sector antennas are typically used for wireless connections between LAN base stations, wireless Internet, subscriber networks, PCS and other point-to-multi. A value of the receive antenna's half power beamwidth, 'Bo', for typical parabolic antennas, where wave length of receive frequency is 'L' and diameter of antenna is 'D', is predicted as follows: 'Bo = 70 x L / D' so that 'Bo' increases with smaller dish diameters. CHANNEL MASTER 4251 REFERENCE ANTENNA: This site is to report the results of continuing field tests using different types of antennas, comparing them to my reference antenna, the Channel Master 4251, a 7-ft. If working correctly, beamwidth will be about 5-8 degrees which is difficult to aim. 2 GHz and calculate the beam width of the antenna. knowledge to properly design and optimize parabolic dish antenna configurations for their associated “low-noise” communication stations. Rotate the antenna display and zoom in for details. com: wi-fi antennas. Circular waveguide antenna showing design values, click to enlarge. The corresponding antenna gain, when the beam points broadside to the aperture, is GO ^ TtNl] ~ TtNj]iJ\a where TJ accounts for antenna losses (i}L) and reduction in gain due to unequal weighting of the elements with a nonuniform amplitude distribution. Horn Antenna Calculator. Antenna Efficiency calculator Antenna Efficiency calculator, parabola antenna: Antenna EiRP calculator enter power, antenna type, frequency, coax type, coax lenght, press for EiRP: Antenna Gain Vs Height This calculator computes the Gain and Elevation angles for various antennas that are mounted over a perfect or lossy ground. The two main considerations of this beam width are Half Power Beam Width (HPBW) and First Null Beam Width (FNBW). This also has vertical or horizontal polarization with the horizontal beam width of 16° and vertical beam width of 12°. The main advantage of a parabolic antenna is that it has high directivity. analyze Yagis, quads, phased arrays, towers, loops -- nearly any type of antenna or parasitic structure. 6 Antenna beamwidth and sidelobe performance. Scribd is the world's largest social reading and publishing site. Tt takes operating frequency(GHz) and diameter as inputs. 4 GHz Wifi antennas is a curation of 76 resources about , Cookie Cantenna Wi-Fi, Uni-Directional WIFI Range Extender, Hot to test a homebrew wifi antenna, How to extend your Wireless Network, Building Helical Antennas - Seattle Wireless. thing is to place an antenna on that latitude/longitude. Ah-450 helical antenna uses extended stubs to provide the greater gain while maintaining the wider beam-width. The vertical beam width can be safely narrowed because one would have to be close to a cell tower to have appreciable elevation of the signal from horizontal (and if one is that close one wouldn't need a cellular repeater). Antenna World G2424 Directional Range Booster WIFI Parabolic Grid Antenna This antenna connects to your wireless card also known as a usb wi-fi adapter or USB wireless adapter, such as the popular Alfa AWUS036H or N700 by simplify or access point / router with a removable antenna which has an external antenna connector only. 5 degrees from boresight. 4GHz, designed to work with Rocket M2 radios to create powerful 2x2 MIMO PtP bridges. A mismatch between signal frequency and antenna design frequency typically causes performance degradation. 63mm, so the SWR curve across the WiFi band is flatter. gain [dBi] 1. We discuss the Pringles Cantenna, Coffee Can Antenna, Parabolic Reflector and Antenna Designs. Assumes uniform stellar density, and (depending upon the direction in which the antenna is aimed) is probably valid only out to about 1000 light-years. Using fishing line you can measure the flatness and then make adjustments until perfectly flat. Antennas useful for radio astronomy at short wavelengths must have collecting areas much larger than the collecting area $\lambda^2 / (4 \pi)$ of an isotropic antenna and much higher angular resolution than a short dipole provides. Usually the two angular domains that we consider are Azimuth and Elevation. Parabolic calculator Cantenna Biquad Trig calculator Quad calculator Video Tutorials Passive Repeater MagicJack MJ Panasonic Fix Curtain Quad 148GTL-D Mods Ham-Radios Hand held Base Cordless-Phones Long range EnGenius Wifi Products High Power Pci Cards USB with antenna Wifi Antennas Pigtails & Coax Yagi Antennas USB Extenders More Routers. Example is the 802. feed for a small parabolic reflector. If the user has a solid dish, he/she should have no problem converting from C band to Ku band. Mountable on wall or pole. The main advantage of a parabolic antenna is that it has high directivity. Following formula is used for this radar antenna beamwidth calculator. All antennas are. 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Channel Master is a leader in over-the-air broadcast entertainment products & solutions, providing the highest quality and value for consumers since 1949. | {"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": 0.7118241190910339, "perplexity": 2517.210268694876}, "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-2019-47/segments/1573496667177.24/warc/CC-MAIN-20191113090217-20191113114217-00018.warc.gz"} |
https://voer.edu.vn/c/electric-potential-in-a-uniform-electric-field/0e60bfc6/4024a853 | Giáo trình
# College Physics
Science and Technology
## Electric Potential in a Uniform Electric Field
Tác giả: OpenStaxCollege
In the previous section, we explored the relationship between voltage and energy. In this section, we will explore the relationship between voltage and electric field. For example, a uniform electric field $\mathbf{\text{E}}$ is produced by placing a potential difference (or voltage) $\Delta V$ across two parallel metal plates, labeled A and B. (See [link].) Examining this will tell us what voltage is needed to produce a certain electric field strength; it will also reveal a more fundamental relationship between electric potential and electric field. From a physicist’s point of view, either $\Delta V$ or $\mathbf{\text{E}}$ can be used to describe any charge distribution. $\Delta V$ is most closely tied to energy, whereas $\mathbf{\text{E}}$ is most closely related to force. $\Delta V$ is a scalar quantity and has no direction, while $\mathbf{\text{E}}$ is a vector quantity, having both magnitude and direction. (Note that the magnitude of the electric field strength, a scalar quantity, is represented by $E$ below.) The relationship between $\Delta V$ and $\mathbf{\text{E}}$ is revealed by calculating the work done by the force in moving a charge from point A to point B. But, as noted in Electric Potential Energy: Potential Difference, this is complex for arbitrary charge distributions, requiring calculus. We therefore look at a uniform electric field as an interesting special case.
The work done by the electric field in [link] to move a positive charge $q$ from A, the positive plate, higher potential, to B, the negative plate, lower potential, is
$W=\phantom{\rule{0.25em}{0ex}}–\Delta \text{PE}=\phantom{\rule{0.25em}{0ex}}–q\Delta V.$
The potential difference between points A and B is
$–\Delta V=\phantom{\rule{0.25em}{0ex}}–\left({V}_{\text{B}}–{V}_{\text{A}}\right)={V}_{\text{A}}–{V}_{\text{B}}={V}_{\text{AB}}.$
Entering this into the expression for work yields
$W={\text{qV}}_{\text{AB}}.$
Work is $W=\text{Fd}\phantom{\rule{0.25em}{0ex}}\text{cos}\phantom{\rule{0.25em}{0ex}}\theta$; here $\text{cos}\phantom{\rule{0.25em}{0ex}}\theta =1$, since the path is parallel to the field, and so $W=\text{Fd}$. Since $F=\text{qE}$, we see that $W=\text{qEd}$. Substituting this expression for work into the previous equation gives
$\mathrm{qEd}={\text{qV}}_{\text{AB}}.$
The charge cancels, and so the voltage between points A and B is seen to be
$\begin{array}{c}\begin{array}{c}{V}_{\text{AB}}=\mathrm{Ed}\\ E=\frac{{V}_{\text{AB}}}{d}\end{array}}\text{(uniform}\phantom{\rule{0.25em}{0ex}}E\phantom{\rule{0.25em}{0ex}}\text{- field only),}\end{array}$
where $d$ is the distance from A to B, or the distance between the plates in [link]. Note that the above equation implies the units for electric field are volts per meter. We already know the units for electric field are newtons per coulomb; thus the following relation among units is valid:
$\text{1 N}/C=\text{1 V}/m.$
What Is the Highest Voltage Possible between Two Plates?
Dry air will support a maximum electric field strength of about $3.0×{\text{10}}^{6}\phantom{\rule{0.25em}{0ex}}\text{V/m}$. Above that value, the field creates enough ionization in the air to make the air a conductor. This allows a discharge or spark that reduces the field. What, then, is the maximum voltage between two parallel conducting plates separated by 2.5 cm of dry air?
Strategy
We are given the maximum electric field $E$ between the plates and the distance $d$ between them. The equation ${V}_{\text{AB}}=\mathrm{Ed}$ can thus be used to calculate the maximum voltage.
Solution
The potential difference or voltage between the plates is
${\text{V}}_{\text{AB}}=\mathrm{Ed}.$
Entering the given values for $E$ and $d$ gives
${V}_{\text{AB}}=\left(3.0×{\text{10}}^{6}\phantom{\rule{0.25em}{0ex}}\text{V/m}\right)\left(0.025 m\right)=7.5×{\text{10}}^{4}\phantom{\rule{0.25em}{0ex}}V$
or
${V}_{\text{AB}}=\text{75 kV}.$
(The answer is quoted to only two digits, since the maximum field strength is approximate.)
Discussion
One of the implications of this result is that it takes about 75 kV to make a spark jump across a 2.5 cm (1 in.) gap, or 150 kV for a 5 cm spark. This limits the voltages that can exist between conductors, perhaps on a power transmission line. A smaller voltage will cause a spark if there are points on the surface, since points create greater fields than smooth surfaces. Humid air breaks down at a lower field strength, meaning that a smaller voltage will make a spark jump through humid air. The largest voltages can be built up, say with static electricity, on dry days.
Field and Force inside an Electron Gun
(a) An electron gun has parallel plates separated by 4.00 cm and gives electrons 25.0 keV of energy. What is the electric field strength between the plates? (b) What force would this field exert on a piece of plastic with a $\text{0.500 μC}$ charge that gets between the plates?
Strategy
Since the voltage and plate separation are given, the electric field strength can be calculated directly from the expression $E=\frac{{V}_{\text{AB}}}{d}$. Once the electric field strength is known, the force on a charge is found using $\mathbf{\text{F}}=q\phantom{\rule{0.25em}{0ex}}\mathbf{\text{E}}$. Since the electric field is in only one direction, we can write this equation in terms of the magnitudes, $F=q\phantom{\rule{0.25em}{0ex}}E$.
Solution for (a)
The expression for the magnitude of the electric field between two uniform metal plates is
$E=\frac{{V}_{\text{AB}}}{d}.$
Since the electron is a single charge and is given 25.0 keV of energy, the potential difference must be 25.0 kV. Entering this value for ${V}_{\text{AB}}$ and the plate separation of 0.0400 m, we obtain
$E=\frac{\text{25}\text{.}\text{0 kV}}{0\text{.}\text{0400 m}}=6\text{.}\text{25}×{\text{10}}^{5}\phantom{\rule{0.25em}{0ex}}\text{V/m}.$
Solution for (b)
The magnitude of the force on a charge in an electric field is obtained from the equation
$F=\mathrm{qE}.$
Substituting known values gives
$F=\left(\text{0.500}×{\text{10}}^{–6}\phantom{\rule{0.25em}{0ex}}\text{C}\right)\left(\text{6.25}×{\text{10}}^{5}\phantom{\rule{0.25em}{0ex}}\text{V/m}\right)=\text{0.313 N}.$
Discussion
Note that the units are newtons, since $\text{1 V/m}=\text{1 N/C}$. The force on the charge is the same no matter where the charge is located between the plates. This is because the electric field is uniform between the plates.
In more general situations, regardless of whether the electric field is uniform, it points in the direction of decreasing potential, because the force on a positive charge is in the direction of $\mathbf{\text{E}}$ and also in the direction of lower potential $V$. Furthermore, the magnitude of $\mathbf{\text{E}}$ equals the rate of decrease of $V$ with distance. The faster $V$ decreases over distance, the greater the electric field. In equation form, the general relationship between voltage and electric field is
$E=\phantom{\rule{0.25em}{0ex}}–\frac{\Delta V}{\Delta s},$
where $\Delta s$ is the distance over which the change in potential, $\Delta V$, takes place. The minus sign tells us that $\mathbf{\text{E}}$ points in the direction of decreasing potential. The electric field is said to be the gradient (as in grade or slope) of the electric potential.
For continually changing potentials, $\Delta V$ and $\Delta s$ become infinitesimals and differential calculus must be employed to determine the electric field.
# Section Summary
• The voltage between points A and B is
$\begin{array}{c}\begin{array}{c}{V}_{\text{AB}}=\mathrm{Ed}\\ E=\frac{{V}_{\text{AB}}}{d}\end{array}}\text{(uniform}\phantom{\rule{0.25em}{0ex}}E\phantom{\rule{0.25em}{0ex}}\text{- field only),}\end{array}$
where $d$ is the distance from A to B, or the distance between the plates.
• In equation form, the general relationship between voltage and electric field is
$E=\phantom{\rule{0.25em}{0ex}}–\frac{\Delta V}{\Delta s},$
where $\Delta s$ is the distance over which the change in potential, $\Delta V$, takes place. The minus sign tells us that $\mathbf{\text{E}}$ points in the direction of decreasing potential.) The electric field is said to be the gradient (as in grade or slope) of the electric potential.
# Conceptual Questions
Discuss how potential difference and electric field strength are related. Give an example.
What is the strength of the electric field in a region where the electric potential is constant?
Will a negative charge, initially at rest, move toward higher or lower potential? Explain why.
# Problems & Exercises
Show that units of V/m and N/C for electric field strength are indeed equivalent.
What is the strength of the electric field between two parallel conducting plates separated by 1.00 cm and having a potential difference (voltage) between them of $1\text{.}\text{50}×{\text{10}}^{4}\phantom{\rule{0.25em}{0ex}}V$?
The electric field strength between two parallel conducting plates separated by 4.00 cm is $7\text{.}\text{50}×{\text{10}}^{4}\phantom{\rule{0.25em}{0ex}}\text{V/m}$. (a) What is the potential difference between the plates? (b) The plate with the lowest potential is taken to be at zero volts. What is the potential 1.00 cm from that plate (and 3.00 cm from the other)?
(a) $3\text{.}\text{00 kV}$
(b) $\text{750 V}$
How far apart are two conducting plates that have an electric field strength of $4\text{.}\text{50}×{\text{10}}^{3}\phantom{\rule{0.25em}{0ex}}\text{V/m}$ between them, if their potential difference is 15.0 kV?
(a) Will the electric field strength between two parallel conducting plates exceed the breakdown strength for air ($3.0×{\text{10}}^{6}\phantom{\rule{0.25em}{0ex}}\text{V/m}$) if the plates are separated by 2.00 mm and a potential difference of $5.0×{\text{10}}^{3}\phantom{\rule{0.25em}{0ex}}\text{V}$ is applied? (b) How close together can the plates be with this applied voltage?
(a) No. The electric field strength between the plates is $2.5×{\text{10}}^{6}\phantom{\rule{0.25em}{0ex}}\text{V/m,}$ which is lower than the breakdown strength for air ($3.0×{\text{10}}^{6}\phantom{\rule{0.25em}{0ex}}\text{V/m}$).
(b) 1.7 mm
The voltage across a membrane forming a cell wall is 80.0 mV and the membrane is 9.00 nm thick. What is the electric field strength? (The value is surprisingly large, but correct. Membranes are discussed in Capacitors and Dielectrics and Nerve Conduction—Electrocardiograms.) You may assume a uniform electric field.
Membrane walls of living cells have surprisingly large electric fields across them due to separation of ions. (Membranes are discussed in some detail in Nerve Conduction—Electrocardiograms.) What is the voltage across an 8.00 nm–thick membrane if the electric field strength across it is 5.50 MV/m? You may assume a uniform electric field.
44.0 mV
Two parallel conducting plates are separated by 10.0 cm, and one of them is taken to be at zero volts. (a) What is the electric field strength between them, if the potential 8.00 cm from the zero volt plate (and 2.00 cm from the other) is 450 V? (b) What is the voltage between the plates?
Find the maximum potential difference between two parallel conducting plates separated by 0.500 cm of air, given the maximum sustainable electric field strength in air to be $3.0×{\text{10}}^{6}\phantom{\rule{0.25em}{0ex}}\text{V/m}$.
$\text{15 kV}$
A doubly charged ion is accelerated to an energy of 32.0 keV by the electric field between two parallel conducting plates separated by 2.00 cm. What is the electric field strength between the plates?
An electron is to be accelerated in a uniform electric field having a strength of $2\text{.}\text{00}×{\text{10}}^{6}\phantom{\rule{0.25em}{0ex}}\text{V/m}$. (a) What energy in keV is given to the electron if it is accelerated through 0.400 m? (b) Over what distance would it have to be accelerated to increase its energy by 50.0 GeV?
(a) $\text{800 KeV}$
(b) $\text{25.0 km}$ | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 85, "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": 0.8998622298240662, "perplexity": 247.89420758299838}, "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/1664030334596.27/warc/CC-MAIN-20220925193816-20220925223816-00344.warc.gz"} |
https://iris.polito.it/handle/11583/2497429 | Korea Superconducting Tokamak Advanced Research (KSTAR) began operation in 2008 and is a fully superconducting tokamak using ITER-like superconductor. All of the SC coils, using cable-in-conduit conductors (CICCs), are cooled with forced-flow supercritical helium (SHe) at 4.5 K and 5.5 bar, to maintain a superconducting state. We consider here the central couple of the PF coils, which during operation is subjected to sharp current transients, which induce AC losses in the superconducting coils due to the change in magnetic field, which leads to the backflow of the helium. The thermal hydraulics due to one of the trapezoidal current pulse in the PF1L coil is analyzed, with ramp up rate of 1 kA/s and ramp down rate of 10 kA/s, with maximum current of 10 kA, using the recently developed 4C code. The main thermal-hydraulic characteristics (evolution of temperatures, pressures, mass flow rates) at different coil locations are computed and compared with the measurements, showing that expected AC losses turns out to be much smaller that the experimental ones.
APPLICATION OF 4C CODE TO THE THERMAL HYDRAULIC ANALYSIS OF AC LOSSES IN THE KSTAR PF SUPERCONDUCTING COILS / Kholia, Akshat; Savoldi, Laura; Zanino, Roberto. - STAMPA. - (2011). ((Intervento presentato al convegno XXIX Congresso UIT sulla Trasmissione del Calore tenutosi a Torino, Italy nel June 2011.
### APPLICATION OF 4C CODE TO THE THERMAL HYDRAULIC ANALYSIS OF AC LOSSES IN THE KSTAR PF SUPERCONDUCTING COILS
#### Abstract
Korea Superconducting Tokamak Advanced Research (KSTAR) began operation in 2008 and is a fully superconducting tokamak using ITER-like superconductor. All of the SC coils, using cable-in-conduit conductors (CICCs), are cooled with forced-flow supercritical helium (SHe) at 4.5 K and 5.5 bar, to maintain a superconducting state. We consider here the central couple of the PF coils, which during operation is subjected to sharp current transients, which induce AC losses in the superconducting coils due to the change in magnetic field, which leads to the backflow of the helium. The thermal hydraulics due to one of the trapezoidal current pulse in the PF1L coil is analyzed, with ramp up rate of 1 kA/s and ramp down rate of 10 kA/s, with maximum current of 10 kA, using the recently developed 4C code. The main thermal-hydraulic characteristics (evolution of temperatures, pressures, mass flow rates) at different coil locations are computed and compared with the measurements, showing that expected AC losses turns out to be much smaller that the experimental ones.
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## Danish Research Center To Explore Mysteries of Earth's Interior56
An anonymous reader writes "The DanSeis Centre at the University of Copenhagen has just received a grant of more than €3 million from the Danish Ministry of Science, Innovation and Higher Education to investigate and tackle one of geoscience's great mysteries: do mantle plumes, hypothetically buoyant regions of heated mantle material rising towards the earth's surface, actually exist?"
This discussion has been archived. No new comments can be posted.
## Danish Research Center To Explore Mysteries of Earth's Interior
• #### Foregone conclusion.... (Score:2)
...it's a plume filled danish.
• #### Re:Foregone conclusion.... (Score:4, Funny)
on Friday March 16, 2012 @04:49AM (#39374971)
If the planet is consuming too many plum filled danishes, I can certainly understand hot bubbles of materials rising up.
Oh, sorry, you said "plume," not "plum." Never mind. Also, for anyone who thought of hot grits and/or Natalie Portman while reading the above, you've got issues bro.
• #### Great News (Score:5, Funny)
on Friday March 16, 2012 @04:14AM (#39374821) Journal
I will be watching this closely, as I have often wondered what on Earth is at the center of a Danish [wikipedia.org].
• #### Re: (Score:1)
Normally that would be "remonce" which is a mix of butter, sugar and often marcipan (or finely chopped almonds)
• #### Re: (Score:2)
That's 'marzipan'.
• #### It's the Bagrols you have to worry about. (Score:2)
Plumes, who cares about feathers deep underground?
• #### What about the discontinuity of gravity? (Score:5, Informative)
on Friday March 16, 2012 @05:01AM (#39375029)
Why is the force of gravity at the core zero?
http://en.wikipedia.org/wiki/File:Earth-G-force.png [wikipedia.org]
http://en.wikipedia.org/wiki/File:Slice_earth.svg [wikipedia.org]
And why the hell is there a Gutenberg discontinuity where gravity increases the closer you get, then drops down to zero?
i.e.
The Gutenberg Discontinuity, is the boundary, as detected by changes in seismic waves, between the Earth's lower mantle and the outer core about 1800 miles below the surface. It is also called the core-mantle boundary.
http://en.wikipedia.org/wiki/Mohorovi%C4%8Di%C4%87_discontinuity [wikipedia.org]
• #### Re:What about the discontinuity of gravity? (Score:5, Informative)
on Friday March 16, 2012 @05:22AM (#39375095)
"Why is the force of gravity at the core zero?"
Because the integral of the forces acting on some mass at the center of the Earth is zero. Or to put it differently: You are being pulled by (approximately) equal forces in all directions.
• #### Re: (Score:2)
IIRC no integral is needed; the vector sum of forces will do.
• #### Re: (Score:2)
"...the vector sum of forces will do."
Yes, assuming point masses. But that means that you are summing atoms. For practical purposes I would make an integral over the volume of the Earth.
• #### Re: (Score:2)
It depends on the definition of centre. If by centre you mean centre of mass, that is the same as saying: "we define the centre to be the place where gravity is zero".
• #### Re:What about the discontinuity of gravity? (Score:4, Informative)
<<ude.ekud.yhp> <ta> <bgr>> on Friday March 16, 2012 @09:55AM (#39376627) Homepage
Gravity does not increase once you are inside the Earth's surface unless perhaps you are moving down towards a large, cow-shaped lode of pure Uranium. Newtonian gravitation satisfies a Gauss Law (like electrostatic fields) and aside from minor perturbation due to the Earth being rotationally deformed and the tides, the field starts at zero at the origin/center and smoothly increases as one moves toward the surface in any direction, then smoothly decreases (like $latex 1/r^2$) once one is outside of it. Rotation (e.g. coriolis forces) alter the perceived local acceleration by a hair as a function of latitude. The slight equatorial bulge and compressibility of the core material keep the field from increasing ideally/linearly (as it would for a perfect sphere of uniform density). Finally, the Sun and the Moon create further local acceleration perturbations that are not strictly speaking variations in the Earth's field, but that result from the non-uniformity of the Sun and Moon's fields and the fact that the center of mass of the Earth has a different acceleration than points on its surface as it interacts with them both (the tides).
None of these things are even slightly mysterious. None of them are really particularly difficult to calculate, or at least estimate. "Interesting" discoveries from the systematic study of near-Earth and inner-Earth gravity are entirely possible, but one would ordinarily consider the discover of a fifth force, or a short range modulation of the gravitational force, to be "interesting" in this context. In order to make such a discovery, however, one has to know the mass distribution and compute the net relative acceleration one should be observing to very high precision, as one is basically looking for an anomaly, and small deviations from a not-too-well-known or even well-defined base quantity are the most difficult to detect, see the entire (somewhat humorous) debate about global warming for an example).
rgb
P.S. -- Off-topic general query: Wordpress lets one embed latex in comments, and it isn't even particularly focussed on technical subject matters. Is there an equally simple way to embed latex in /. comments? I'd put the ideal form of gravitation inside a sphere inline into this reply, except that nobody wants to read things like \vec{g} = -\frac{GMr}{R^3} \hat{r} or the derivation of same in latex unless they know latex well enough to read it as rendered...
• #### It isn't zero (Score:2)
It is just a lot in any direction. Same reason you are not a stain on the ground from the massive pressure off all the air on top of you. Air pressure is all around and the same all around.
A funny thing is that in theory, if you could drill a hole through the planet and you could jump down it and there was no air resistance you would pop out at the other end at the same speed as you entered. first you accelerate and then you decelerate. Of course, it would never work in real life but it is a fun idea.
For a
• #### Re: (Score:2)
It isn't zero. It is just a lot in any direction.
My physics is rusty, but I'm pretty sure if there's zero acceleration, there's zero force.
• #### Danish... (Score:2)
Crispy on the outside, soft and chewy in the middle?
• #### Dinosaurs, giant diamonds and atomic bombs (Score:2)
It all sounds so cool! Sign me up!
• #### Arne Saknussemm (Score:1)
I wonder if they have Arne Saknussemm working for them? Wasn't he a Dane that led a trail to the Center of the Earth http://en.wikipedia.org/wiki/Journey_to_the_Center_of_the_Earth/ [wikipedia.org]
• #### Re: (Score:1)
by Anonymous Coward
He was Icelandic as I recall. Of course, at the time of Jules Verne, Iceland was technically part of Denmark..
• #### Didn't one of the old versions of... (Score:2)
Didn't one of the earlier versions of "Journey to the Center of the Earth" involve a Dane with a duck?
• #### Re: (Score:2)
Nope. I was thinking that there were Danes involved in that too, but a walk through Wikipedia reveals apparently not. The explorer in Verne's original novel was German. Arne Saknussemm, the (fictional) medieval alchemist whose lead they were following, was an Icelander. Other incarnations have varied things; in the movie (and later animated series) with the duck, the explorer was Scottish. There was one version with a Swede involved. But apparently no Danes.
• #### There is nothing down there but dirt! (Score:1)
Seriously! Yet another gold digging expedition in the name of "Science"
• #### Re: (Score:1)
Scientist playing Minecraft in IRL
• #### Danish (Score:3, Funny)
on Friday March 16, 2012 @07:08AM (#39375437)
The horrible abominations you call Danish pastry over in the US, I wouldn't even feed to the pigs. I wouldn't mind my nationality being associated with a custard-filled fatty pastry, if only it was a delicious custard-filled fatty pastry. For heaven's sake, turn them into bio fuel or something, because they certainly aren't suitable for human consumption.
Same goes for your coffee, by the way. :-)
• #### Re: (Score:2)
You have a point, but not ALL of our stuff sucks. Same thing with beer; if you look at the small producers, we have some pretty good stuff.
• #### Re: (Score:2)
Of course, this is just in jest. At least I know now to politely turn it down, if the company secretary wants to book you into a Holiday Inn, stateside.
Waitress: "D'ya want some more coffee, Hon?"
Me: "NO, NO, I mean, eehhh, no thank you,"
Your large selection of weird brew-beers was a positive surprise, though.
• #### Re: (Score:2)
... Danish pastry over in the US, I wouldn't even feed to the pigs...
Well, DUH. Neither would I. Why would you give something so awesomely yummy to a pig?
• #### Re: (Score:2)
American chocolate has to be the worst in the world.
• #### Just another remake (Score:1)
Reminds me of something: now what was that... There's a Danish researcher and a goose, an older scientist and his young apprentice and a rich lady in pink stretch pants. Are we sure this wasn't an announcement from Disney studios?
• #### Pellucidar (Score:2)
The hollow-earthers were right! The GOP hopefuls should probably campaign on gaining ownership of the natural resources of Pellucidar; it'd fit right in with their anti-anthropomorphic climate change, sustainable fossil fuels, and creationism beliefs. :-D
• #### Old News (Score:2)
I thought that these questions had been conclusively settled, as chronicled in that fine documentary The Core
• #### Inferno? Jon Pertwee? Bueler? Bueler? (Score:2)
Am I the only person who watched Doctor Who reruns on PBS in the 80s? http://en.wikipedia.org/wiki/Inferno_(Doctor_Who) [wikipedia.org]
• #### Re: (Score:2)
Actually, after reading the headline my first thought was of Arne Saknussemm!
• #### Investigatory team (Score:1)
They are sending one scientist, one mountain guide, one unqualified but attractive lab assistant and the guide's pet duck into an extinct volcano to investigate.
#### Related LinksTop of the: day, week, month.
How come everyone's going so slow if it's called rush hour?
Working... | {"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": 0.6707216501235962, "perplexity": 3971.3063195457894}, "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/1476988719542.42/warc/CC-MAIN-20161020183839-00431-ip-10-171-6-4.ec2.internal.warc.gz"} |
http://jpsoft.com/help/which.htm | # Take Command / TCC Help v. 19.0
Purpose: Display the command type and what it would execute
Format: WHICH [/A] command [command ...]
command One or more commands or files.
/A(ll)
Usage:
WHICH displays information about internal and external commands, Aliases (including keystroke aliases), files, plugin variables, internal variables, and variable functions. When a file matches an applicable Executable Extension or Windows File Association, that data will be displayed. The exact information reported depends on the type of command or file you specify. For example:
[c:\] which cdd buildtree notepad test.btm test.exe test.xyz test.doc donothing
CDD is an internal command
buildtree is an alias : cdd /s
test.btm is a batch file : C:\test.btm
test.exe is an external : C:\test.exe
test.xyz is an executable extension : C:\path\mybatch.btm C:\test.xyz
test.doc is associated with : C:\Program Files\Microsoft Office\OFFICE11\WINWORD.EXE
donothing is an unknown command
If the command is an abbreviated alias, WHICH will display the full name; i.e.:
[c:\] alias opt*ions=*option
[c:\] which opt
opt*ions is an alias : *option
A leading * will skip the alias test (i.e., if dir is an alias, *dir will return the internal command).
WHICH can also recognize Plugin commands, REXX files, EXTPROC files, and associated files.
Note: WHICH does not support wildcard specifications unless you use the /A option. Parameters must be actual commands or actual file names (including variable and function references as in "which %comspec"). If a filename includes white space or special characters, it must be enclosed in double quotes. A file specified without an explicit path must be on the current PATH.
See Executable Files and File Searches for details on the order in which various locations are searched.
Option:
/A Display all matching names. (Normally WHICH only displays the first match.) Executable files will be displayed in the order they are found in the PATH. | {"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": 0.8789023160934448, "perplexity": 9828.049068232127}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "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-2016-07/segments/1454701166650.78/warc/CC-MAIN-20160205193926-00188-ip-10-236-182-209.ec2.internal.warc.gz"} |
https://murray.cds.caltech.edu/index.php?title=CDS_140a_Winter_2014_Homework_8&diff=18228&oldid=16940 | # Difference between revisions of "CDS 140a Winter 2014 Homework 8"
R. Murray Issued: 25 Feb 2014 (Tue) ACM 101b/AM 125b/CDS 140a, Winter 2014 Due: 5 Mar 2014 (Wed) @ noon
__MATHJAX__
Note: In the upper left hand corner of the second page of your homework set, please put the number of hours that you spent on this homework set (including reading).
1. Perko, Section 4.1, Problem 1:
(a) Consider the two vector fields
<amsmath>
f(x) = \begin{bmatrix} -x_2 \\ x_1 \end{bmatrix}, \qquad
g(x) = \begin{bmatrix} -x_2 + \mu x_1 \\ x_1 + \mu x_2 \end{bmatrix}.
</amsmath>
Show that $\|f-g\|_1 = |\mu| (\max_{x \in K} \|x\| + 1)$, where $K \subset {\mathbb R}^2$ is a compact set containing the origin in its interior.
(b) Show that for $\mu \neq 0$ the systems
<amsmath>
\aligned \dot x_1 &= -x_2 \\ \dot x_2 &= x_1 \endaligned \quad\text{and}\quad
\aligned \dot x_1 &= -x_2 + \mu x_1 \\ \dot x_2 &= x_1 + \mu x_2 \endaligned
</amsmath>
are not topologically equivalent.
Hint: Let $\phi_t$ and $\psi_t$ be the flows defined by these two systems and assume that there is a homeomorphism $H:{\mathbb R}^2 \to {\mathbb R}^2$ and a strictly increasing, continuous function $t(\tau)$ mapping $\mathbb R$ onto $\mathbb R$ such that $\phi_{t(\tau)} = H^{-1} \circ \psi_\tau \circ H$. Use the fact that $\lim_{t\to\infty} \phi_t(1,0) \neq 0$ and that for $\mu < 0$, $\lim_{t \to \infty} \psi_t(x) = 0$ for all $x \in {\mathbb R}^2$ to arrive at a contradiction.
2. Consider the dynamical system
<amsmath>
m \ddot q + b \dot q + k q = u(t), \qquad
u(t) = \begin{cases} 0 & t = 0, \\ 1 & t > 0, \end{cases} \qquad
q(0) = \dot q(0) = 0,
</amsmath>
which describes the "step response" of a mass-spring-damper system.
(a) Derive the differential equations for the sensitivities of <amsmath>q(t) \in {\mathbb R}</amsmath> to the parameters <amsmath>b</amsmath> and <amsmath>k</amsmath>. Write out explicit systems of ODEs for computing these, including any initial conditions. (You don't have to actually solve the differential equations explicitly, though it is not so hard to do so.)
(b) Compute the sensitivities and the relative (normlized) sensitivies of the equilibrium value of <amsmath>q_e</amsmath> to the parameters <amsmath>b</amsmath> and <amsmath>k</amsmath>. You should give explicit formulas in terms of the relevant parameters and initial conditions.
(c) Sketch the plots of the relative sensitivities <amsmath>S_{q,b}</amsmath> and <amsmath>S_{q,k}</amsmath> as a function of time for the nominal parameter values <amsmath>m = 1</amsmath>, <amsmath>b = 2</amsmath>, <amsmath>k = 1</amsmath>.
3. Perko, Section 4.2, Problem 4: Consider the planar system
<amsmath>
\aligned
\dot x &= \mu x - x^2 \\
\dot y &= -y.
\endaligned
</amsmath>
Verify that the system satisfies the conditions for a transcritical bifurcation (equation (3) in Section 4.2) and determine the dimensions of the various stable, unstable and center manifolds that occur.
4. Perko, Section 4.2, Problem 7: Consider the two dimensional system
<amsmath>
\aligned
\dot x &= -x^4 + 5 \mu x^2 - 4 \mu^2 \\
\dot y &= -y.
\endaligned
</amsmath>
Determine the critical points and the bifurcation diagram for this system. Draw phase portraits for the various values of $\mu$ and draw the bifurcation diagram. | {"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": 0.9999092817306519, "perplexity": 737.9474018436687}, "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-2022-05/segments/1642320304883.8/warc/CC-MAIN-20220129092458-20220129122458-00488.warc.gz"} |
https://www.mpim-bonn.mpg.de/node/6449/abstracts | # Abstracts for Seminar on Higher Structures
Alternatively have a look at the program.
## What is higher Lie theory?
Posted in
Speaker:
Dmitry Roytenberg
Affiliation:
Utrecht/Amsterdam
Date:
Fri, 2016-01-08 14:00 - 15:00
Location:
MPIM Lecture Hall
Lie theory" refers to a functorial correspondence between
finite-dimensional Lie algebras and 1-connected Lie groups, elucidated
by Sophus Lie and summarized in his three theorems, Lie I, II and III.
The first hint that there might be more to the story came from van Est
who noticed (and proved) that integrating higher Lie algebra cocycles
required higher connectivity assumptions on the Lie group. Furthermore,
attempts to build a Lie theory for Lie algebroids (and
infinite-dimensional Lie algebras) generally run into obstructions of a
## Generalized cohomology of M2/M5-branes
Posted in
Speaker:
Urs Schreiber
Affiliation:
CAS Prague/MPIM
Date:
Fri, 2016-01-15 14:00 - 15:00
Location:
MPIM Lecture Hall
While it is well-known that the charges of F1/Dp-branes in type II string theory need to be refined from de Rham cohomology to certain twisted generalized differential cohomology theories, it is an open problem to determine the generalized cohomology theory for M2-brane/M5-branes in 11 dimensions. I discuss how a careful re-analysis of the old brane scan (arXiv:1308.5264 , arXiv:1506.07557, joint with Fiorenza and Sati) shows that rationally and unstably, the M2/M5 brane charge is in degree-4 cohomotopy.
## $L_\infty$ algebras governing simultaneous deformations in algebra and geometry
Posted in
Speaker:
Yaël Frégier
Affiliation:
U d'Artois/MPIM
Date:
Fri, 2016-01-29 14:00 - 15:00
Location:
MPIM Lecture Hall
We will explain how simultaneous deformations problems in algebra and geometry are naturally governed by non quadratic $L_\infty$ algebras and how such algebras can be constructed by super geometry or operad theory, depending on the applications.
This will be illustrated with examples. We will consider simultaneous deformations of pairs such as couples of algebras/morphisms, coisotropic/Poisson, Dirac/Courant, generalized complex/Courant (if time permits).
## Open-closed homotopy algebras
Posted in
Speaker:
Martin Doubek
Affiliation:
Charles Univ. Prague/MPIM
Date:
Fri, 2016-02-19 14:00 - 15:00
Location:
MPIM Lecture Hall
Topological types of string worldsheets can be organised into a modular operad QP. For closed strings, algebras over this operad are essentially topological quantum field theories formalized by monoidal functors from cobordisms into vector spaces or by commutative Frobenius algebras. There is an analogous picture for open and open/closed strings. In the closed case, QP can be freely generated from certain cyclic suboperad P via modular envelope: in fact P=Com. In the open case, analogous result holds for P=Ass. In open-closed case, this problem is subtler.
## Rational homotopy of the little cubes operads and graph complexes
Posted in
Speaker:
Benoit Fresse
Affiliation:
Université de Lille/MPIM
Date:
Fri, 2016-02-26 14:00 - 15:00
Location:
MPIM Seminar Room
I will report on a joint work with Victor Turchin and Thomas Willwacher about the rational homotopy of the little cubes operads (equivalently, the little discs operads).
## Ginzburg--Kapranov criterion for Koszulness of operads, and its limitations
Posted in
Speaker:
Affiliation:
Trinity College Dublin
Date:
Fri, 2016-03-04 14:00 - 15:00
Location:
MPIM Lecture Hall
In their seminal paper on operadic Koszul duality, Ginzburg
and Kapranov established a remarkable functional equation that holds
whenever an operad is Koszul. I shall discuss some examples
demonstrating that non-Koszul operads do not have to violate that
criterion, in either of two possible ("weak" or "strong") senses.
## What good is a semi-model structure on algebras over an operad?
Posted in
Speaker:
David White
Affiliation:
Denison University, Granville
Date:
Fri, 2016-03-11 14:00 - 15:00
Location:
MPIM Lecture Hall
In general, it is difficult to transfer a model structure from a monoidal
model category M to the category of algebras over a (colored) operad P in M.
Often, one only ends up with a semi-model structure (i.e. where half the
factorization and lifting axioms only hold for maps with cofibrant domain),
and even this traditionally requires P to be Sigma-cofibrant. I?ll explain
what standard techniques still work in the context of semi-model categories,
so that users of model categories can get by if they only have a semi-model
## An Algebraic Combinatorial Approach to Opetopic Structure
Posted in
Speaker:
Marcelo Fiore
Affiliation:
U of Cambridge, UK
Date:
Wed, 2016-03-23 10:30 - 12:00
Location:
MPIM Lecture Hall
The starting point of this talk will be an algebraic connection to be presented briefly between
the theory of abstract syntax of [1,2] and the approach to opetopic sets of [4]. This realization
conceptually allows us to transport viewpoints between these mathematical theories and I
will explore it here in the direction of higher-dimensional algebra leading to opetopic
categorical structures. The technical work will involve setting up a microcosm principle
for near-semirings and subsequently exploiting it in the cartesian closed bicategory of
© MPI f. Mathematik, Bonn Impressum & Datenschutz | {"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": 0.7077807188034058, "perplexity": 3690.411899041426}, "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/1570986684854.67/warc/CC-MAIN-20191018204336-20191018231836-00352.warc.gz"} |
http://www.bio.net/bionet/mm/proteins/2005-August/011726.html | # [Protein-analysis] Re: how to make protein unfold curve
Frank Küster frank at kuesterei.ch
Tue Aug 30 08:10:32 EST 2005
"subberry" <zhangpy at gmail.com> wrote:
> It's so kind of you to give so detailed answers.
>
> "the borderline was around 600V for the high voltage of
> the detector"
>
> Yes, i recorded the HT. Is that say whet the HT above 600V, the data si
> not creditable? My spectrometers is Jasco 810.
Yes, approximately at 600V. You should see it easily in the data, too.
Especially the buffer blank will start to scatter wildly at wavelengths
where the HT is too high - there's simply not enough light to be able to
calculate the difference between the absorbance of right- and left
circular polarized light.
> "For a monomeric protein, there's no reason to assume that it unfolds
> slower, or not at all, if the protein concentration is increased."
>
> Is that say a monomeric protein must be unfolded at all? And what is
> the relationship between this and protein concentration? How about
> inclusion bosy?
Let's first assume that the protein does *not* aggregate. For the
reaction between folded F and unfolded U, you have:
F <==> U
and the equilibrium constant is
[F]
K = ---
[U]
(or upside down, as you like it). Let's define the total concentration
c_0 = [F] + [U] => [U] = c_0 - [F]
now:
[F]
K = ---------
c_0 - [F]
solving this for \alpha = [F] / c_0, the fraction of native molecules,
gives
\alpha c_0 \alpha
K = ---------------- = --------
c_0 - \alpha c_0 1-\alpha
K
\alpha = ---
1+K
All this is of course dependent on the guanidine concentration, but at a
given [GdnHCl], \alpha, the fraction of native molecules, is independent
of protein concentration. On the other hand if you have a homodimer:
F_2 <==> 2 U
[F_2]
K = -----
[U]^2
(where [U]^2 means [U] squared, F_2 means F index 2). Now the total concentration is
c_0 = [F_2] + [U] (in terms of monomers)
and
2 [F_2]
\alpha = ------- or 2 [F_2] = \alpha c_0
c_0
substituting this into the equation for K, we get
1/2 \alpha c_0 1/2 \alpha c_0
K = ---------------------- = ------------------
(c_0 - \alpha c_0)^2 c_0^2 (1-\alpha)^2
Even without explicitly solving this for \alpha, you can see that c_0
doesn't cancel out, and that the fraction of native molecules will
depend on c_0.
You can also explain it with the Le Chatelier principle ("principle of
least force" or similar): If you increase the number of particles, the
equilibrium will be shifted towards the side that has a lower number of
particles, thus escaping the "force" of more particles.
So this means: If you have a monomeric protein, and you know that it
unfolded at 5M GdnHCl at one particular protein concentration, you know
that it is also unfolded at 5M at other protein concentrations.
Therefore, if you prepare a concentrated unfolded stock solution, you
On the other hand, if the protein is a dimer (or more complicated
oligomer), you have to check whether it is really unfolded
*at*exactly*the*concentration*used*. Of course once you've calculated K
(and are sure about the stoichiometry), you can simply calculate
\alpha.
Now, when it comes to aggregates, things get even more complicated.
Usually aggregates dissolve readily in 6M GdnHCl, but some don't, or
rather take very long. You should be able to monitor that by light
scattering. There are some proteins that tend to aggregate when you
store them for long, or when they are frozen and thawed repeatedly, but
when you denature them and renature them again, the renatured solution
is native, active, fine :-).
> "light scattering is a good method for that"
>
> what type spectrometers can do this? what i have is Zeta Potential from
> brookhaven, is it okay?
I must admit that I never used light scattering intensively myself. For
a first check, even measuring the amount of scattered light by looking
at the apparent "absorbance" at wavelengths above 300nm might be
sufficient. But when you have a real light scattering instrument that
even gives you an estimate of the size of the particles, you're lucky.
Regards, Frank
--
In der Zeit, in der man einen defekten Riegel derartig seziert hat, dass man
verlässlich bestimmte Speicherbereich als "heile" garantieren(!) kann, kann
man auch Pfandflaschen im Stadtpark sammeln, dass reicht dann für einen
doppelt so großen neuen Riegel. ;) [Jörg Rossdeutscher in d-u-g at l.d.o] | {"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": 0.8429744243621826, "perplexity": 7457.178662280819}, "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-2014-49/segments/1416931010402.68/warc/CC-MAIN-20141125155650-00150-ip-10-235-23-156.ec2.internal.warc.gz"} |
http://mathhelpforum.com/math-topics/188834-compound-monthly-interest-question.html | # Math Help - Compound Monthly Interest question
1. ## Compound Monthly Interest question
This is a question from a text book. plz help and solve it.
The Huang family purshased a motor home by borrowing $30,000 at 9%/a compounded monthly. The Huang will make payments at the end of each month. They have two choices for the term: 5 years and 8 years a) Determine the monthly payments for each term. b) How much money would they save by choosing the shorter term. I tried to do find the total amount after 5 years which is$46,970.43 and 8 year is $61,467.64. As I subtracted the 5 year total from 30,000 and divide by 5x12 months, I got$282.84 for a) but the book says its $622.75 so apparantly im wrong. The book also says for 8 year term it is 439.51 and b) is$4827.96.
Help asap!!?? any answer is welcome!
2. ## Re: Compound Monthly Interest question
This is a question from a text book. plz help and solve it.
The Huang family purshased a motor home by borrowing $30,000 at 9%/a compounded monthly. The Huang will make payments at the end of each month. They have two choices for the term: 5 years and 8 years a) Determine the monthly payments for each term. b) How much money would they save by choosing the shorter term. I tried to do find the total amount after 5 years which is$46,970.43 and 8 year is $61,467.64. As I subtracted the 5 year total from 30,000 and divide by 5x12 months, I got$282.84 for a) but the book says its $622.75 so apparantly im wrong. The book also says for 8 year term it is 439.51 and b) is$4827.96.
Help asap!!?? any answer is welcome!
your text should have a formula for calculating payments ...
$P = A \cdot \frac{r(1+r)^n}{(1+r)^n - 1}$
$P$ = monthly payment
$A$ = amount financed
$r$ = monthly interest
$n$ = total number of monthly payments
... plug and chug on a calculator.
3. ## Re: Compound Monthly Interest question
so to simplify that P=A*r/-1? i plug the values in the equation you gave me and it gave me an extravagant number. World Transit Facility, sorry the book is more like a question book with answers.
4. ## Re: Compound Monthly Interest question
so to simplify that P=A*r/-1? i plug the values in the equation you gave me and it gave me an extravagant number. wtf. sorry the book is more like a question book with answers.
you cannot cancel the $(1 + r)^n$ in the formula ... review your basic algebra.
$A = 30000$
$r = \frac{.09}{12}$
for 5 years, $n = 60$
5. ## Re: Compound Monthly Interest question
oh yeah true. i often forget that yu cant cancel out if multiplication is present. thanks anywayz
6. ## Re: Compound Monthly Interest question
I tried to do find the total amount after 5 years which is $46,970.43 and 8 year is$61,467.64.
Those are the FV's of \$30,000 after 5 and 8 years: has NOTHING to do with the problem.
IF as you say this is "a question from a text book", WHY do you need answer "asap"?
7. ## Re: Compound Monthly Interest question
^because its homework and students are expected to do it? b) requires the subtraction of term 1 and term 2. I also tried to solve a) by dividing the answer by 60 months. Do you understand?
8. ## Re: Compound Monthly Interest question
I will not do your homework.
Perhaps someone else will, but I doubt it. | {"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": 9, "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": 0.4465532600879669, "perplexity": 2502.07708359752}, "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-2015-48/segments/1448398464253.80/warc/CC-MAIN-20151124205424-00304-ip-10-71-132-137.ec2.internal.warc.gz"} |
http://mathhelpforum.com/pre-calculus/19800-co-ordinate-geometry-help.html | 1. ## Co-ordinate geometry help
Hi, what is the best way to find the equation of a straight line when given to points on the line. ie (x1,y1) and (x2,y2)
I have been finding the gradient m=y2-y1/x2-x1 and then putting into the formula y-y1 =m(x-x1) but i am doing something wrong as i keep getting different answers to my textbook. Could somebody please solve one for me so i can see how it's done?
Heres one in my book Find the equation of the line AB when A(-2,4) B(5,3)
Thanks, Chris.
2. Find $m$
$m=\frac{3-4}{5+2}=-\frac17$
Now select one point and apply the point-slope formula.
3. The equation of a line passing through two points $M_1(x_1,y_1), \ M_2(x_2,y_2)$ is
$\displaystyle\frac{x-x_1}{x_2-x_1}=\frac{y-y_1}{y_2-y_1}$
or $\displaystyle\begin{vmatrix}x & y & 1\\x_1 & y_1 & 1\\x_2 & y_2 & 1\end{vmatrix}=0$
4. Hi thanks. Yes i know the formula, it's just i am having trouble using it i am going wrong somewhere with it.
5. Originally Posted by Chris85
Hi thanks. Yes i know the formula, it's just i am having trouble using it i am going wrong somewhere with it.
Why don't you post your solution and we'll take a look at it.
-Dan
6. OK
A=(-2,4) B=(5,3)
M= y2-y1/x2-x1 = 3-4/5-(-2) = -1/7
y-y1/y2-y1 = x-x1/x2-x1
therefore y-4/3-4 = x-(-2)/5-(-2)
Am i right so far if so what do i do next?? apologies if it's hard to understand im new and still trying to do the latex
7. Originally Posted by Chris85
OK
A=(-2,4) B=(5,3)
M= y2-y1/x2-x1 = 3-4/5-(-2) = -1/7
y-y1/y2-y1 = x-x1/x2-x1
therefore y-4/3-4 = x-(-2)/5-(-2)
Am i right so far if so what do i do next?? apologies if it's hard to understand im new and still trying to do the latex
Hello,
you calculated the slope of the line correctly.
Now you plug in the coordinates of one point into the equation of the line:
point-slope-formula, see Krizalid's post.
$\frac{y-y_1}{x-x_1} = m~\implies~\frac{y-3}{x-5}=-\frac17$ Solve for y:
$y-3 = -\frac17 \cdot(x-5)$ expand the bracket and solve for y:
$y = -\frac17 \cdot x + \frac{26}7$
8. ok, the answer in my textbook is x+7y-26=0??
9. Originally Posted by Chris85
ok, the answer in my textbook is x+7y-26=0??
Hi,
take the result I gave you, multiply both sides by 7 and collect all terms on the LHS - then you'll get the answer which is in your book. | {"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": 8, "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": 0.8084627389907837, "perplexity": 630.4810103648838}, "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/1476988719079.39/warc/CC-MAIN-20161020183839-00549-ip-10-171-6-4.ec2.internal.warc.gz"} |
https://1kingdomlifeministrydwightwaller.com/2017/08/20/casting-thy-burdens/ | # “Casting thy burdens”
## Cast thy burden upon the LORD, and he shall sustain thee, he shall never suffer the righteous to be moved.
cast thy burden upon the (Mat.6:25> Therefore I say unto you, Take no thought for your life, what you shall eat, or what you shall drink; nor yet for your body, what you shall put on. Is not the life more than meat, and the body than raiment? Luke 12:22> And he said unto his disciples, Therefore I say unto you, Take no thought for your life, what ye shall eat; neither for the body, what ye shall put on.) Phil. 4:6> Be careful for nothing; but in every thing by prayer and supplication with thanksgiving let your requests be made known unto God. (Ps.55:22,- Prov.16:3- 1Pet.5:7>Commit thy works unto the LORD, and thy thoughts shall be established. Casting all your care upon him; for he careth for you.
he shall never suffer the righteous to be moved.(Ps.37: 23-24> The steps of a good man are ordered by the LORD: and he delights in his way. Though he fall, he shall not be utterly cast down: for the LORD upholds him with his hand.
Trust in the Lord, O son of righteousness, for He is worthy of your esteem. He is infinitely capable of caring for your needs and will always work even the most difficult of situations for benefit. Cast all your cares upon Him for He will be faithful to deliver you. Stand ever in your righteous hope in Christ and you shall not be moved. | {"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": 0.8694925904273987, "perplexity": 10447.056707512975}, "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-2020-45/segments/1603107894426.63/warc/CC-MAIN-20201027170516-20201027200516-00222.warc.gz"} |
http://mathhelpforum.com/calculus/17286-differential-equation-print.html | # differential equation
• Jul 28th 2007, 11:44 AM
viet
differential equation
solve $y'' - 3y' - 10 y = 0; \quad y = 1, y'=10 \;\textnormal{at}\; x = 0$
$y(x) =$
heres what i did:
$r^2-3r-10 = 0$
$(r-2) (r-5) = 0$
roots are : -2, 5
General solution: $y = C_1 e^{-2x}+C_2 e^{5x}$
$y' = -2C_1 e^{-2x}+5C_2 e^{5x}$
i need help applying the condition
• Jul 28th 2007, 11:54 AM
CaptainBlack
Quote:
Originally Posted by viet
solve $y'' - 3y' - 10 y = 0; \quad y = 1, y'=10 \;\textnormal{at}\; x = 0$
$y(x) =$
heres what i did:
$r^2-3r-10 = 0$
$(r-2) (r-5) = 0$
roots are : -2, 5
General solution: $y = C_1 e^{-2x}+C_2 e^{5x}$
$y' = -2C_1 e^{-2x}+5C_2 e^{5x}$
i need help applying the condition
The initial condition $y(0)=1$ gives:
$
C_1+C_2=1
$
and the condition $y'(0)=10$ gives:
$
-2~C_1+5~C_2=10
$
So now you have a pair of simultaneous equations for $C_1$ and $C_2$ to solve.
RonL
• Jul 28th 2007, 04:50 PM
topsquark
Quote:
Originally Posted by viet
solve $y'' - 3y' - 10 y = 0; \quad y = 1, y'=10 \;\textnormal{at}\; x = 0$
$y(x) =$
heres what i did:
$r^2-3r-10 = 0$
$(r-2) (r-5) = 0$
roots are : -2, 5
General solution: $y = C_1 e^{-2x}+C_2 e^{5x}$
$y' = -2C_1 e^{-2x}+5C_2 e^{5x}$
i need help applying the condition
For the record, the characteristic equation factors as
$(r + 2)(r - 5) = 0$
Given that you have the solution to the differential equation correct I would guess this is merely a typo?
-Dan
• Jul 28th 2007, 07:25 PM
viet
yeah it was a typo, thanks for pointing that out topsquark
• Jul 29th 2007, 07:39 PM
viet
Quote:
Originally Posted by CaptainBlack
The initial condition $y(0)=1$ gives:
$
C_1+C_2=1
$
and the condition $y'(0)=10$ gives:
$
-2~C_1+5~C_2=10
$
So now you have a pair of simultaneous equations for $C_1$ and $C_2$ to solve.
RonL
can you explain how to solve that? im pretty much lost.
• Jul 29th 2007, 08:22 PM
ThePerfectHacker
Quote:
Originally Posted by viet
can you explain how to solve that? im pretty much lost.
This is just a linear system.
Say,
$C_1+C_2=5$
$C_1-C_2=1$
$2C_1=6\implies C_1=3$
And so on ....
The same idea here.
• Jul 29th 2007, 08:46 PM
CaptainBlack
Quote:
Originally Posted by CaptainBlack
The initial condition $y(0)=1$ gives:
$
C_1+C_2=1
$
and the condition $y'(0)=10$ gives:
$
-2~C_1+5~C_2=10
$
So now you have a pair of simultaneous equations for $C_1$ and $C_2$ to solve.
RonL
To solve these multiply the firs equation by 2 to get:
$
2~C_1+2~C_2=2
$
Now add the third equation to this (that is add the left hand sides, which
sum is equal to the sum of the right hand sides):
$
2~C_1+2~C_2-2~C_1+5~C_2=2+10
$
or:
$
7~C_2=12
$
so:
$
C_2=12/7
$
Now substitute this back into the first equation to get:
$
C_1=-5/7
$
RonL | {"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": 45, "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": 0.9683700799942017, "perplexity": 2019.4859034022609}, "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-2017-04/segments/1484560284405.58/warc/CC-MAIN-20170116095124-00312-ip-10-171-10-70.ec2.internal.warc.gz"} |
https://scoop.eduncle.com/coding-decoding-questions-tips-and-tricks | Government Jobs Follow
Eduncle posted an Article
June 15, 2019 • 12:21 pm
# Coding Decoding Reasoning Questions – Know How to Solve the Problems!
Reasoning is one of the easiest sections in all type of competitive exams.
There are some topics in reasoning that takes a very short time to get solved while some are time-consuming.
Coding Decoding is a topic which is counted in the list of easiest topics in reasoning section.
If you attempt the Coding Decoding questions, it will help you to score good marks in less consumed time.
Below in this blog, we have shared some useful Coding Decoding tricks and tips that you can use to solve all type of questions asked in the exam.
## What is the Concept of Coding Decoding – Know About Coding Decoding Question and Answers!
Coding is a way to transfer a message from one person to another without knowing it by the third person.
So, the process of decoding the coded data by using the key that is present either within the question or within the options.
There are different patterns of Coding and Decoding Questions asked in IBPS, SSC, Railway and in other competitive exams. Following are the most common types of Coding Decoding questions –
Letter Coding
Substitution
Mixed Letter Coding
New Pattern of Coding
For brief information about all these types, scroll down the blog.
Targeting Upcoming SSC Exams 2018-2019? Get Free Study Materials and Previous Year Question Papers. Download Now.
### Letter Coding
In this type of Coding and Decoding Questions, the given alphabets in a word are replaced by the other alphabets as per some specific rules or pattern of question.
You have to detect the pattern of questions asked and the certain rule that will help you decode the given word.
Below is the perfect example to solve Letter Coding Decoding Problems.
Example -
In a certain code ‘LIMCA’ is written as ‘HJLDZ’. Which of the following words is written as ‘IFWJBP’
Solution
If you see, both the given words ‘LIMCA’ and ‘HJLDZ’ are following the same pattern.
Here each letter moves +1, -1,…. Alternately except for L, which is -4.
Now, you have to follow the same pattern to decode the word ‘IFWJBP’.
As per the above-mentioned pattern you should add 4 to I then, -1,+1 alternately to the remaining letters.
M is +4 to I
E is -1 to F
X is +1 to W
I is -1 to J
C is +1 to B
O is -1 to P
By following the pattern, the answer you will get is MEXICO.
### Substitution Coding
In this type, the questions are based on some certain object names like birds, furniture etc.
The names/objects or words are substituted with different words or objects.
If you want to get the right answer, then carefully go through all the substitutions given in the question.
Let’s explain it with a perfect example
Example –
If the sky is called sea, sea is called water, water is called air, air is called cloud and cloud is called river, then what do we drink when thirsty?
Solution –
If someone is thirsty, he/she will go for water.
If you trace all the substation from the beginning, in the give question Water is called Air. So, the answer is Air.
### Mixed Letter Coding
The Coding and Decoding problems based on the mixed letter are hard to be cracked.
In this type of questions, the messages will be given in coded language. The number of messages may vary in each question.
You will be asked to separate out the code for a particular word from the given messages.
To solve this type of Coding Decoding problem, you have to analyse the common codes in different messages. For each word, there will be a common code in all messages.
You can use for finding codes for every word in the messages or sentences.
Check out the example below –
Example
In a certain code language,
(A) ‘pit dar na’ means ‘you are good’
(B) ‘dar tok pa’ means ‘good and bad’
(C) ‘tim na tok’ means 'they are bad’
In that language, which word stands for 'they’?
Solution -
To solve this problem, just see all the statements carefully to see the common codes and words.
As you have to find the code for the word ‘they’ so concentrate on the statement in which the word is used.
If you see in the first and third statement, the common code is ‘na’ and the common word is ‘are’.
So, ‘na’ means ‘are’.
In the second and third statements, the common code is ‘tok’ and the common word is ‘bad’.
Now, the remaining word in statement third is ‘they’ and the remaining code is ‘tim’.
Thus, ‘tim’ stands for ‘they’.
Download Railway Exam study material and prepare for RRB NTPC, JE-SSE, ALP, Group C & D!
### New Pattern Coding
It’s a newly merged pattern that improved the level of Coding Decoding questions in various government jobs exams.
Nowadays, these type of questions are probably asked in all type of competitive exams.
To know how to crack the new pattern Coding and Decoding questions, check the example with a detailed explanation below.
Example –
"Life extra wonderful now" is coded as "4@I 5#E 9=O 3%O"
"Music is natural medicine" is coded as "5#U 2^I 7&A 8*E"
"Eating vegetable makes healthy" is coded as "6$E 9=E 5#A 7&E" "Health and Money balance" is coded as "6$E 3%A 5#O 7&A"
What is the code for “Balanced diet”?
Solution –
1. The word Balanced in the given statements represents the number of letters in the word.
In the word ‘Balanced’, there are 8 letters, so the code will start from 8.
2. The symbol in the given code is based upon the table given below.
Number of Letters in the Word Symbol 2 ^ 3 % 4 @ 5 # 6 \$ 7 & 8 * 9 =
3. Let’s take an example with the word ‘DIGIT’. Here the number of letters is 5, so the middle code that we use for DIGIT would be #.
4. The letter in the code represents the first vowel from the left end in the given word. Here ‘I’ is the first vowel in the given word from the left side, so the code will end with ‘I’.
Hence the code for the given word “Balanced Diet” will be 8*A4@I
Probability Concepts
Inequality Questions
Number Series
Blood Relation Tricks & Tips
Venn Diagram
Simplification
Here in this blog, we have discussed all type of Coding Decoding Questions which are likely to be asked in the competitive exams.
Start practicing by using these methods and tricks to boost up the score in reasoning section.
If there is any doubt or query regarding the tricks, feel free to ask. Drop your queries in comments’ box. | {"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": 0.3516348600387573, "perplexity": 2027.38492495559}, "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/1600400206133.46/warc/CC-MAIN-20200922125920-20200922155920-00790.warc.gz"} |
http://itknowledgeexchange.techtarget.com/itanswers/error-message-rnx9001/?watch=24665 | error message RNX9001
pts.
Tags:
Programming Languages
RPG
I have a RPGILE which input X and Y and return Z as (X to the power of Y) eg X = 2 and Y = 2 then Z = 4 I define X, Y and Z as 30P9 However when I can this function with parmeter X= 10 and Y = 10 Error occur like this : Can anyone tell me how to fix it or why error come out ? Many thanks ILE RPG/400 FORMATTED DUMP Program Status Area: Procedure Name . . . . . . . . . . . . : GETPOWERVL Program Name . . . . . . . . . . . . . : GETPOWERVL Library . . . . . . . . . . . . . . : PFTSTLIB Module Name. . . . . . . . . . . . . . : GETPOWERVL Program Status . . . . . . . . . . . . : 00202 The call to ended in error (C G D F). Previous Status . . . . . . . . . . . : 00000 Statement in Error . . . . . . . . . . : 00006400 RPG Routine . . . . . . . . . . . . . : GETPOWER Number of Parameters . . . . . . . . . : Message Type . . . . . . . . . . . . . : MCH Additional Message Info . . . . . . . : 1212 Message Data . . . . . . . . . . . . . : Invalid floating point format change detected
Thanks. We'll let you know when a new response is added.
30p9 ** 30p9 has a result in 60p18, that does not exists.
try rounding the result
eval(h) z = x ** y; or
eval z = %decimal(x ** y : 30 : 9);
or try to adjust variables (less decimals)
or eval the result in a double float, such as explained in the “Precision of Intermediate Results” chapter of ILE rpg reference SC09-2508-04 page 429 (pdf page number 447) | {"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": 0.8961087465286255, "perplexity": 344.0276634802359}, "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-2016-36/segments/1471982954852.80/warc/CC-MAIN-20160823200914-00031-ip-10-153-172-175.ec2.internal.warc.gz"} |
http://greenemath.com/Prealgebra/16/OrderofOperationsTest4.html | Sections:
# Order of Operations Test #4
In this section, we finish up our review of whole numbers by discussing the order of operations. When we tackle a problem with multiple operations it can often cause confusion as to which operation is to be performed in which order. Let’s suppose we saw the following problem:
4 + 2 x 3
How would we know whether to add 4 and 2, or multiply 2 times 3 to get started? The order of operations solves this type of dilemma and enables all parties to get a consistent answer. We generally use the acronym PEMDAS to remember the order of operations.
PEMDAS:
1. P: Stands for Parentheses - this is where we begin, work inside of any parentheses or grouping symbols
2. E: Stands for Exponents - we next evaluate all exponent operations
3. M, D: Stands for Multiply or Divide - working from left to right
4. A, S: Stands for Addition or Subtraction - working from left to right
Example 1: 5 x 4 + 22
P: Look for parentheses or grouping symbols - none are present
E: Look for exponents, we see that we have 22 which evaluates to 4
5 x 4 + 4
M, D: Look for multiplication and/or division, we see that we have 5 x 4 which evaluates to 20
20 + 4
A, S: Look for addition and/or subtraction, we see that we have 20 + 4 which evaluates to 24, this is our answer
5 x 4 + 22 = 24 | {"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": 0.8307002186775208, "perplexity": 669.9688898906337}, "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-2018-39/segments/1537267156724.6/warc/CC-MAIN-20180921013907-20180921034307-00519.warc.gz"} |
https://talkstats.com/threads/need-help-interpreting-question.78364/#post-232824 | # Need help interpreting question
*solved
Last edited:
#### Buckeye
##### Active Member
Yes, they seem to be different questions. The lambda and the mu should be supplied to you or you should be able to calculate it given the info in the problem. Not sure where you are getting the lambda as 4 because it is not implied by the info you shared. The 1.75 seems correct assuming you calculated the average of service times correctly. But again, it seems you have omitted some info from the problem. | {"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": 0.9819473028182983, "perplexity": 355.54308754779396}, "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/1659882573399.40/warc/CC-MAIN-20220818185216-20220818215216-00342.warc.gz"} |
https://hackage.haskell.org/package/aeson-1.5.0.0/docs/Data-Aeson-Parser.html | aeson-1.5.0.0: Fast JSON parsing and encoding
Copyright (c) 2012-2016 Bryan O'Sullivan(c) 2011 MailRank Inc. BSD3 Bryan O'Sullivan experimental portable None Haskell2010
Data.Aeson.Parser
Description
Efficiently and correctly parse a JSON string. The string must be encoded as UTF-8.
It can be useful to think of parsing as occurring in two phases:
• Identification of the textual boundaries of a JSON value. This is always strict, so that an invalid JSON document can be rejected as soon as possible.
• Conversion of a JSON value to a Haskell value. This may be either immediate (strict) or deferred (lazy); see below for details.
The question of whether to choose a lazy or strict parser is subtle, but it can have significant performance implications, resulting in changes in CPU use and memory footprint of 30% to 50%, or occasionally more. Measure the performance of your application with each!
Synopsis
Lazy parsers
The json and value parsers decouple identification from conversion. Identification occurs immediately (so that an invalid JSON document can be rejected as early as possible), but conversion to a Haskell value is deferred until that value is needed.
This decoupling can be time-efficient if only a smallish subset of elements in a JSON value need to be inspected, since the cost of conversion is zero for uninspected elements. The trade off is an increase in memory usage, due to allocation of thunks for values that have not yet been converted.
Parse any JSON value.
The conversion of a parsed value to a Haskell value is deferred until the Haskell value is needed. This may improve performance if only a subset of the results of conversions are needed, but at a cost in thunk allocation.
This function is an alias for value. In aeson 0.8 and earlier, it parsed only object or array types, in conformance with the now-obsolete RFC 4627.
Warning
If an object contains duplicate keys, only the first one will be kept. For a more flexible alternative, see jsonWith.
Parse any JSON value. Synonym of json.
Parse a quoted JSON string.
Parse a JSON number.
Handling objects with duplicate keys
jsonWith :: ([(Text, Value)] -> Either String Object) -> Parser Value Source #
Parse any JSON value.
This parser is parameterized by a function to construct an Object from a raw list of key-value pairs, where duplicates are preserved. The pairs appear in reverse order from the source.
Examples
Expand
json keeps only the first occurence of each key, using fromList.
json = jsonWith (Right . fromList)
jsonLast keeps the last occurence of each key, using fromListWith (const id).
jsonLast = jsonWith (Right . fromListWith (const id))
jsonAccum keeps wraps all values in arrays to keep duplicates, using fromListAccum.
jsonAccum = jsonWith (Right . fromListAccum)
jsonNoDup fails if any object contains duplicate keys, using parseListNoDup.
jsonNoDup = jsonWith parseListNoDup
Variant of json which keeps only the last occurence of every key.
Variant of json wrapping all object mappings in Array to preserve key-value pairs with the same keys.
Variant of json which fails if any object contains duplicate keys.
Strict parsers
The json' and value' parsers combine identification with conversion. They consume more CPU cycles up front, but have a smaller memory footprint.
Parse any JSON value.
This is a strict version of json which avoids building up thunks during parsing; it performs all conversions immediately. Prefer this version if most of the JSON data needs to be accessed.
This function is an alias for value'. In aeson 0.8 and earlier, it parsed only object or array types, in conformance with the now-obsolete RFC 4627.
Warning
If an object contains duplicate keys, only the first one will be kept. For a more flexible alternative, see jsonWith'.
Strict version of value. Synonym of json'.
Handling objects with duplicate keys
jsonWith' :: ([(Text, Value)] -> Either String Object) -> Parser Value Source #
Strict version of jsonWith.
Variant of json' which keeps only the last occurence of every key.
Variant of json' wrapping all object mappings in Array to preserve key-value pairs with the same keys.
Variant of json' which fails if any object contains duplicate keys. | {"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": 0.2036263346672058, "perplexity": 4662.137518765898}, "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-2020-29/segments/1593657163613.94/warc/CC-MAIN-20200715070409-20200715100409-00540.warc.gz"} |
https://mathoverflow.net/questions/2396/solving-polynomial-equations-when-you-know-in-which-number-field-the-solutions-li | # Solving polynomial equations when you know in which number field the solutions live
Suppose I have a bunch of polynomial equations with coefficients in a number field, and suppose further that I'm guaranteed a priori that they have a solution in that number field. Can I leverage that knowledge into a technique for solving the equations more easily? The cases we care about are massively overdetermined systems of linear and quadratic equations.
-
I am curious about the origin of the equations you are interested in. Could you say a few words about it ? – jvp Oct 25 '09 at 2:12
Over R, systems of quadratic equations (especially massively overdetermined ones) are no easier to solve than general systems of equations, by Kempe's Universality Theorem for linkages. (Tim Abbott and I have an unpublished paper on this.) I'm not sure whether the proof works rationally, though. – Reid Barton Oct 25 '09 at 4:31
The origin of the equations is trying to construct fusion categories and subfactors by hand. The equations come from relations that we know to be satisfied. – Noah Snyder Oct 25 '09 at 17:10
By Scott's remark, it seems that the linear terms do not suffice for determining the set S. (what is the expected cardinality of S, btw?) I know nothing about programming or complexity, but my suggestion is to try taking the 2-duple embedding. Sure, you replace P^20 by P^200 or so, but now you end up with linear equations in the variables X_ij = x_i x_j. Of course, you still have the quadratic equations in X_ij which determine the image of the 2-uple embedding, but at least now you will have 10^5 linear terms and then < 200 quadratics, even if you have a few more variables... If you are lucky, the linear space cut out in P^200 might actually be quite small.
-
Practically speaking: I would try to reduce the equations modulo several small primes (or prime powers), solve them by brute force, and then try to lift to solutions in your number field using the chinese remainder theorem. It might be helpful to combine this with solving them to high precision over the real (or complex) numbers.
-
Somewhat better? Find a local solution with invertible Jacobian, on a subset of equations maybe, and use a Newton technique to lift it high, so that LLL (p-adic) will find it in the number field. I don't think that $R$ or $C$ will help as well as p-adic for converging. What is the expected field degree, and size of the solutions? The largest I have seen with this is 8-10 variables and field degree 50-100. The work should be for finding the local solution. – Junkie Apr 30 '10 at 8:14
I have to say that this sounds suspiciously close to Matiyasevich's proof of Hilbert's 10th problem (Yuri V. Matiyasevich, Hilbert's Tenth Problem, MIT Press, Cambridge, Massachusetts, 1993). The "yoga" of his proof is that you can have some "Godel coding" on systems of quadratic and linear forms, which shows that solving a system of such equations is hard from a logic/TCS point of view.
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Should be able to use Groebner bases and elimination theory to do it, I think. Though in the case of linear and quadratic equations, I'm not sure how much help it will be.
-
No no, these are massively overdetermined. In typical examples, we're looking at >10^5 quadratics in 20 variables. Our experience so far with Groebner bases has been unhappy -- you can't just hand off the entire list of equations to a Groebner basis implementation and expect it to cope with modern RAM constraints. If this sounds wrong, please tell us! – Scott Morrison Oct 25 '09 at 6:46
Ahh, if they're THAT overdetermined, I can't really offer much help to you. I don't really have anything that can handle those numbers. – Charles Siegel Oct 25 '09 at 14:58
Generally Groebner basis algorithms are doubly exponential, never let them NEAR anything of that magnitude – Michael Hoffman Oct 29 '09 at 14:59
One minor comment: if you can ever reduce to solving equations in a single variable, and looking for rational roots, then you can use the rational root theorem. You can reduce to the case where your number field is the rationals easily enough. (For example, if you started out looking for roots in Q(i), write everything as a+bi.) But I don't know that there is any good way to reduce to equations in a single variable.
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I don't think there's any reason to suspect that there's a good way to reduce to equations in a single variable. A system of n quadratics of the form x_{k+1} = x_k^2 + c reduces to a single polynomial, but of degree 2^n, and I see no reason that one should expect to be able to do any better even for this special case. – Qiaochu Yuan Nov 15 '09 at 20:32
Well, it's certainly easier to intersect lines and quadrics. I would simply go on intersecting all lines, and then select some nicer quadrics to intersect until I'm having a finite set of points, from which I would eliminate the wrong points by using more quadrics until one is left, the answer.
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Typically, by the time we get down to a finite set of points, that finite set would have size 2^20 or so. Not fun in practice. – Scott Morrison Oct 25 '09 at 6:48 | {"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": 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": 0.6241868138313293, "perplexity": 398.7839502284881}, "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/1438042987866.61/warc/CC-MAIN-20150728002307-00165-ip-10-236-191-2.ec2.internal.warc.gz"} |
http://cms.math.ca/cjm/msc/32A35?fromjnl=cjm&jnl=CJM | location: Publications → journals
Search results
Search: MSC category 32A35 ( $H^p$-spaces, Nevanlinna spaces [See also 32M15, 42B30, 43A85, 46J15] )
Expand all Collapse all Results 1 - 5 of 5
1. CJM Online first
Cascante, Carme; Fàbrega, Joan; Ortega, Joaquín M.
Sharp norm estimates for the Bergman operator from weighted mixed-norm spaces to weighted Hardy spaces In this paper we give sharp norm estimates for the Bergman operator acting from weighted mixed-norm spaces to weighted Hardy spaces in the ball, endowed with natural norms. Keywords:weighted Hardy space, Bergman operator, sharp norm estimateCategories:47B38, 32A35, 42B25, 32A37
2. CJM 2011 (vol 64 pp. 1329)
Izuchi, Kei Ji; Nguyen, Quang Dieu; Ohno, Shûichi
Composition Operators Induced by Analytic Maps to the Polydisk We study properties of composition operators induced by symbols acting from the unit disk to the polydisk. This result will be involved in the investigation of weighted composition operators on the Hardy space on the unit disk and moreover be concerned with composition operators acting from the Bergman space to the Hardy space on the unit disk. Keywords:composition operators, Hardy spaces, polydiskCategories:47B33, 32A35, 30H10
3. CJM 2009 (vol 62 pp. 439)
Sundhäll, Marcus; Tchoundja, Edgar
On Hankel Forms of Higher Weights: The Case of Hardy Spaces In this paper we study bilinear Hankel forms of higher weights on Hardy spaces in several dimensions. (The Schatten class Hankel forms of higher weights on weighted Bergman spaces have already been studied by Janson and Peetre for one dimension and by Sundhäll for several dimensions). We get a full characterization of Schatten class Hankel forms in terms of conditions for the symbols to be in certain Besov spaces. Also, the Hankel forms are bounded and compact if and only if the symbols satisfy certain Carleson measure criteria and vanishing Carleson measure criteria, respectively. Keywords:Hankel forms, Schattenâvon Neumann classes, Bergman spaces, Hardy spaces, Besov spaces, transvectant, unitary representations, Möbius groupCategories:32A25, 32A35, 32A37, 47B35
4. CJM 1998 (vol 50 pp. 99)
Izuchi, Keiji; Matsugu, Yasuo
$A_\phi$-invariant subspaces on the torus Generalizing the notion of invariant subspaces on the 2-dimensional torus $T^2$, we study the structure of $A_\phi$-invariant subspaces of $L^2(T^2)$. A complete description is given of $A_\phi$-invariant subspaces that satisfy conditions similar to those studied by Mandrekar, Nakazi, and Takahashi. Categories:32A35, 47A15
5. CJM 1997 (vol 49 pp. 653)
Cascante, Carme; Ortega, Joaquin M.
On $\lowercase{q}$-Carleson measures for spaces of ${\cal M}$-harmonic functions In this paper we study the $q$-Carleson measures for a space $h_\alpha^p$ of ${\cal M}$-harmonic potentials in the unit ball of $\C^n$, when \$q Categories:32A35, 31C15
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https://www.manhattanprep.com/gre/challengeproblems/ | ## Challenge Problem of the Month
I will choose one person out of all the people who answer correctly to win a free Manhattan GRE Strategy Guide. If you're keen on calculations or on winning free things, you should try your hand this month.
### This Month's Problem: "These Three Integers"
x, y, and z are positive integers.
$y< 1 5 z MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garmWu51MyVXgaruWqVvNCPvMCG4uz3bqefqvATv2CG4uz3bIuV1wy Ubqee0evGueE0jxyaibaieYhNi=xH8yiVC0xbbL8F4rqqrFfpeea0x e9Lq=Jc9vqaqpepm0xbbG8FasPYRqj0=yi0dXdbba9pGe9xq=JbbG8 A8frFve9Fve9Ff0dmeaabaqaciGacaGaaeqabaWaaqaafaaakeaaca WG5bGaeyipaWZaaSaaaeaacaqGXaaabaGaaeynaaaacaWG6baaaa@3C5C@$ $1 3 x− 3 4 y= 1 6 z MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garmWu51MyVXgaruWqVvNCPvMCG4uz3bqefqvATv2CG4uz3bIuV1wy Ubqee0evGueE0jxyaibaieYhNi=xH8yiVC0xbbL8F4rqqrFfpeea0x e9Lq=Jc9vqaqpepm0xbbG8FasPYRqj0=yi0dXdbba9pGe9xq=JbbG8 A8frFve9Fve9Ff0dmeaabaqaciGacaGaaeqabaWaaqaafaaakeaada WcaaqaaiaabgdaaeaacaqGZaaaaiaadIhacqGHsisldaWcaaqaaiaa iodaaeaacaaI0aaaaiaadMhacqGH9aqpdaWcaaqaaiaabgdaaeaaca qG2aaaaiaadQhaaaa@414D@$
Quantity A
x
Quantity B
z
Quantity A is greater.
Quantity B is greater.
The two quantities are equal.
The relationship cannot be determined from the information given. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 2, "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": 0.3070674240589142, "perplexity": 1866.705473250548}, "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/1461860127983.53/warc/CC-MAIN-20160428161527-00217-ip-10-239-7-51.ec2.internal.warc.gz"} |
http://math.stackexchange.com/questions/296281/convolution-of-l-1-functions-is-l-1 | # Convolution of $L_1$ functions is $L_1$
Let $f,g\in L_1(\mathbb R, m)$ where m is the Lebesgue measure.
Prove that:
a) $f(x-t)g(t) \in L_1(\mathbb R, m)$ as a fuction of $t$ almost all $x$
b) $h\in L_1(\mathbb R, m)$ where $h=(f \ast g)(t)=\int_{\mathbb R}f(x-t)g(t)dm(t)$
c)$||h||_{L_1}\le ||f||_{L_1}||g||_{L_1}$
-
Hint: Use Fubini on $\mathbb{R}^2$ for the function $G(x,t)=|f(x-t)g(t)|$. | {"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": 0.9957208633422852, "perplexity": 194.8867345895289}, "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/1461860110805.57/warc/CC-MAIN-20160428161510-00134-ip-10-239-7-51.ec2.internal.warc.gz"} |
https://infoscience.epfl.ch/record/188872?ln=en | ## Asynchronous Gossip
We study the complexity of gossip in an asynchronous, message-passing fault-prone distributed system. We show that an adaptive adversary can significantly hamper the spreading of a rumor, while an oblivious adversary cannot. The algorithmic techniques proposed in this article can be used for improving the message complexity of distributed algorithms that rely on an all-to-all message exchange paradigm and are designed for an asynchronous environment. As an example, we show how to improve the message complexity of asynchronous randomized consensus.
Published in:
Journal of The ACM, 60, 2
Year:
2013
Publisher:
New York, Association for Computing Machinery
Keywords:
Laboratories: | {"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": 0.9517655968666077, "perplexity": 1128.6027314194064}, "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-2019-30/segments/1563195525973.56/warc/CC-MAIN-20190719012046-20190719034046-00240.warc.gz"} |
http://www.quepublishing.com/articles/article.aspx?p=131120&seqNum=3 | # Using DOS Commands with MS-DOS 6.22
• Print
From the author of
## Understanding the Elements of a DOS Command
To begin to understand DOS commands, you first need to know a few fundamental facts:
• DOS requires that you use a specific set of rules, or syntax, when you issue commands.
• All DOS commands begin with a keyword that identifies the action you want performed.
• Parameters, which are a part of a command's syntax, refine the way a command is executed.
Syntax is the order in which you type the elements of the DOS command—its grammar. If you say, "Ball red the choose I," people probably will not understand that you are trying to say, "I choose the red ball." Some people might understand what you are trying to say, but not many. A computer, on the other hand, has no intelligence or imagination; it can interpret commands only according to its programming. Programming several optional syntaxes for commands requires using a great deal of extra memory and disk space, which cuts down on the resources available to do real work. That's why you have to supply the intelligence and imagination and why you must enter DOS commands precisely according to the rules of command syntax.
You can think of the command keyword as the action part, or verb, of a DOS command. In addition to the keyword, many commands require or allow further directions. You supply these directions as parameters and switches. Parameters tell DOS what action to take or how to apply the action. Using DOS commands is easy as long as you follow the rules of order and use the correct parameters. After you know the basic rules, you often can figure out parameters for commands that you don't use on a regular basis.
NOTE
You run applications software—such as word processors or drawing programs—by entering a command at the DOS prompt. The command you use to start an application is the name of the program file (COM or EXE) in which the programming for the software is stored.
Most applications software incorporates the issuing of commands as part of the software's operation. The commands discussed in this book are DOS commands. Be sure that you know the difference between DOS commands, which you issue at the DOS command line, and the commands you learn to use with your applications software.
If you are unsure whether a command you have been taught to use is part of DOS, look in Appendix F, "Command Reference." If that command is not listed, it is an application program command, not a DOS command.
### The Command Syntax
The syntax for most DOS commands can be boiled down to one of the following two simple formats:
```KEYWORD Drive\Files Switches
KEYWORD SourceFiles TargetFiles Switches```
A DOS command always begins with the keyword, which is the name of the command, followed by a space. If you use the language metaphor, the keyword is the verb that specifies the action to be taken.
The first example shows the common form for DOS commands that don't change files in some way. The Drive\Files portion of the example is a parameter that specifies what drive or files on which the command is supposed to act. This parameter is analogous to a noun in English. In other words, the parameter is the thing on which the verb acts. This portion of the syntax is in italic to show that the parameter is optional. The parameter also can be followed by command-line switches. To extend the language metaphor, switches are like adverbs; they modify the verb. They change the action to be done.
The second example here is typical of the syntax for most DOS commands that operate on groups of files. The keyword, of course, specifies the action, followed by two parameters that indicate the disk or files that provide the data source for the action. The second parameter indicates the target disk or files. To copy a group of files from one disk or directory to another, for example, you can use the following command:
`COPY A:Myfile.TXT B:Yourfile.TXT`
This command copies a file having the name MYFILE.TXT on drive A into the memory of your computer and then writes the contents of the file onto drive B using the name YOURFILE.TXT.
NOTE
Some parameters or switches are optional, meaning that some parts of the command syntax, such as the keyword, are mandatory. When you enter only the mandatory command elements, DOS (in most cases) uses default parameters for other elements.
A good example is the COPY command. If the following is the command, the default target is the currently logged disk and directory:
`COPY A:MyFile.TXT`
If you're in C:\TEMP, the file is copied to that directory, and the current filename, MYFILE.TXT, is the target filename as well.
As you can see, having defaults makes commands easier to use and shorter, and gives you fewer opportunities to make mistakes.
Because many DOS commands have several parameters, switches, and defaults, different forms of these commands might be correct. You seldom, if ever, use all the optional syntax for any command. Some switches actually are mutually exclusive. You cannot format a floppy disk as both high density and low density, for example.
To find out what options are available for any given command, you should look up the command in the "Command Reference" later in this book. The first time you look up a complex command, don't let the sheer volume of optional parameters and switches throw you for a loop. Even the simplest of DOS commands has several options.
The way the syntax is presented often is called the paradigm. Even the simple DOS commands have an imposing paradigm. A good example is the DIR command, a real workhorse of a command. Its paradigm looks something like the following:
`DIR filespec /P /W /S /B /L /C /CH /O:sortorder /A:attributes`
You use the DIR command to display a directory of one or more files stored on a disk. This command might look formidable, but it is much easier to understand if you break down the individual components.
→ For a description of the DIR command and its options, see "Listing Files with the DIR Command" in Chapter 8, "Managing Your Files", p. 193.
The Command-Line Parameters
In addition to the command's name, a DOS command contains syntax elements known as parameters. Parameters (sometimes called arguments) are the parts of a command line that provide DOS with the objects of the command's action. The objects might be files, system settings, or hardware devices.
In the DIR example in the preceding section, filespec is the complete filename, including any drive, path, and wildcards that you want the DIR command to use. In some commands, you might see the filespec spelled out, as in the following:
`d:path\filename.ext`
Don't be confused by this formal rendering of the filespec; it simply states that the filespec can contain a drive letter, a pathname, a filename, and an extension.
NOTE
Many new users are confused about the way slashes and backslashes are used in commands. In actuality, their uses are stated simply in two rules:
• Backslashes (\) are used as separators (delimiters) when specifying directory and file information.
• Slashes (/), sometimes called forward slashes, are used as signals to DOS that the next character is a command-line switch.
A good memory association to use is that a backslash connects one name back to the name that comes before it, whereas a slash connects to the character in front of it.
### The Optional Switches
A switch is a parameter that turns on an optional function of a command. Switches are special parameters because they usually are not the objects of a command's action; rather, switches modify the command's action. You can use the /W switch with the DIR command, for example, to display a wide directory of files instead of the usual single-column list. Switches can make a basic command more versatile and powerful. In the DIR example, /P, /W, /S, /B, /L, /O, /C, /CH, and /A are switches.
Usually, you can use a command's switches in any order or any combination. Not all DOS commands have switches, however. Also, the letter used for a switch in one DOS command might have a different meaning in another DOS command. In addition, some switches require a parameter. You usually attach switch parameters to the switch by using a colon (:), as in the following example:
`FORMAT A: /F:360 /S`
In this example, the /F switch specifies that a 360KB floppy disk be formatted in a disk drive that normally uses high-density (1.2MB) disks. | {"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": 0.8973608613014221, "perplexity": 1726.9055972670596}, "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-2016-50/segments/1480698542250.48/warc/CC-MAIN-20161202170902-00043-ip-10-31-129-80.ec2.internal.warc.gz"} |
http://math.stackexchange.com/questions/687581/derive-differentiation-identity-for-gegenbauer-polynomial | # Derive Differentiation Identity for Gegenbauer Polynomial
For $\lambda > 0$ and $n = 0,1,2,3,\ldots$, the following is an n-th order polynomial: $$P_{\lambda,n}(x)=(1-x^{2})^{-\lambda+1/2}\frac{d^{n}}{dx^{n}}(1-x^{2})^{n+\lambda-1/2}$$ Problem: Show that there are constants $C_{\lambda,n}$ such that $$P_{\lambda,n}'(x)=C_{\lambda,n}P_{\lambda+1,n-1}(x),\;\; \lambda > 0,\;\; n \ge 1.$$ I'd like to see a way to verify this using only basic calculus.
Background: The Gegenbauer polynomials, $G_{\lambda,n}$ are the unique polynomial coefficients in the power series expansion $$\frac{1}{(1-2rx+r^{2})^{\lambda}} = \sum_{n=0}^{\infty}G_{\lambda,n}(x)r^{n},\;\;\; |r| < 1, \; |x| \le 1,\; \lambda > 0.$$ (In the special case that $\lambda=1/2$, the Gegenbauer polynomials are the Legendre polynomials.) Differentiating the above with respect to $x$, and equating like powers of $r$, leads to the identity $$\frac{d}{dx}G_{\lambda,n}(x)=2\lambda G_{\lambda+1,n-1}(x),\;\;\; \lambda > 0,\; n\ge 1.$$ This identity is equivalent the one I have asked to be shown because the Gegenbauer polynomials have a Rodrigues Formula $G_{\lambda,n}(x)=c_{\lambda,n}P_{\lambda,n}$ for some constants $c_{\lambda,n}$. I would have thought that the first-order derivative relation $G_{\lambda,n}'=2\lambda G_{\lambda,n}$ would be obvious from the Rodrigues formula for $G_{\lambda,n}$, but I'm having trouble seeing it.
References:
1. A version of the Rodrigues formula $G_{\lambda,n}=c_{\lambda,n}P_{\lambda,n}$ and the constants $c_{\lambda,n}$ are found in
http://en.wikipedia.org/wiki/Gegenbauer_polynomials
2. A version of the stated recurrence $G_{\lambda,n}'=2\lambda G_{\lambda+1,n-1}$ is found in
http://en.wikipedia.org/wiki/Classical_orthogonal_polynomials#Gegenbauer_polynomials
- | {"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": 0.9868817329406738, "perplexity": 137.38678164402714}, "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-2015-27/segments/1435375095677.90/warc/CC-MAIN-20150627031815-00243-ip-10-179-60-89.ec2.internal.warc.gz"} |
http://proceedings.asmedigitalcollection.asme.org/volume.aspx?volumeid=18438 | 0
### ASME Conference Presenter Attendance Policy and Archival Proceedings
2017;():V07AT00A001. doi:10.1115/OMAE2017-NS7A.
FREE TO VIEW
This online compilation of papers from the ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering (OMAE2017) represents the archival version of the Conference Proceedings. According to ASME’s conference presenter attendance policy, if a paper is not presented at the Conference by an author of the paper, the paper will not be published in the official archival Proceedings, which are registered with the Library of Congress and are submitted for abstracting and indexing. The paper also will not be published in The ASME Digital Collection and may not be cited as a published paper.
Commentary by Dr. Valentin Fuster
### Ocean Engineering: Advanced Ship Hydromechanics and Marine Technology
2017;():V07AT06A001. doi:10.1115/OMAE2017-61011.
Modern ships are supported by internet of things (IoT) to collect ship performance and navigation information. That should be utilized towards digitalization of the shipping industry. However, such information collection systems are always associated with large-scale data sets, so called Big Data, where various industrial challenges are encountered during the respective data handling processes. This study proposes a data handling framework with data driven models (i.e. digital models) to cope with the shipping industrial challenges as the main contribution, where conventional mathematical models may fail. The proposed data driven models are developed in a high dimensional space, where the respective ship performance and navigation parameters of a selected vessel are separated as several data clusters. Hence, this study identifies the distribution of the respective data clusters and the structure of each data cluster in relation to ship performance and navigation conditions. An appropriate structure into the data set of ship performance and navigation parameters is assigned by this method as the main contribution. However, the domain knowledge (i.e. vessel operational and navigation conditions) is also included in this situation to derive a meaningful data structure.
Topics: Vessels
Commentary by Dr. Valentin Fuster
2017;():V07AT06A002. doi:10.1115/OMAE2017-61051.
The added resistance of a ship was calculated using Maruo’s formula [1] involving the three-dimensional Kochin function obtained using the source and normal doublet distribution over the wetted surface of the ship. The density of the doublet distribution was obtained as the solution of the three-dimensional frequency-domain forward-speed Green integral equation containing the exact line integral along the waterline. Numerical results of the Wigley ship models II and III in head seas, obtained by making use of the inner-collocation 9-node second-order boundary element method have been compared with the experimental results reported by Journée [2]. The forward-speed hydrodynamic coefficients of the Wigley models have shown no irregular-frequencylike behavior. The steady disturbance potential due to the constant forward speed of the ship has also been calculated using the Green integral equation associated with the steady forward-speed free-surface Green function since the so-called mj-terms [3] appearing in the body boundary conditions contain the first and second derivatives of the steady potential over the wetted surface of the ship. However, the free-surface boundary condition was kept linear in the present study. The added resistances of the Wigley II and III models in head seas obtained using Maruo’s formula showing acceptable comparison with experimental results, have been presented. The added resistances in following seas obtained using Maruo’s formula have also been presented.
Topics: Ships
Commentary by Dr. Valentin Fuster
2017;():V07AT06A003. doi:10.1115/OMAE2017-61110.
The development of loading and unloading operations is an essential part of the logistical chain of maritime transportation. One of the determining factors in this process is the movement of moored ships, which has a notable influence over the efficiency of the operation. The implementation of systems to characterize their real behavior would provide an important tool for the management of these activities.
In this context the Water and Environmental Engineering Group (GEAMA) at the University of A Coruña, Spain (UDC), through different projects executed in collaboration with the Port Authority of A Coruña (Spain), has developed an integrated system for monitoring the dynamic behavior of moored vessels. This system includes different devices which allow to characterize their six degrees of freedom and tensions in certain mooring lines.
The analysis of motions is carried out using three combined technologies. Ship rotations (roll, pitch and yaw) are registered by means of an Inertial Measurement Unit (IMU) developed by the Research Group. The translations of heave and surge are analyzed with a visual tracking system using fixed cameras deployed near the location. Finally, the evaluation of sway motion and an additional measure of yaw are obtained using two laser-distance meters located over the dock.
All devices integrated in the system were calibrated in laboratory at the R+D Centre CITTEC-UDC with several series of tests. Once the methodology was validated, the system has been employed in different projects carried out in Inner and Outer Ports of the city of A Coruña, with more than 30 monitored ships.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A004. doi:10.1115/OMAE2017-61137.
Frequency-domain methods are proven efficient and reliable, especially for zero forward speed, in early design stage for the prediction of ship motions and wave-induced wave loads. There are still challenges for ships with forward-speed due to the inaccuracy in the computation of m-terms. In this paper, the panel-free method is further improved to predict motions and wave-induced loads on real ships with forward speeds. A simple algorithm has been developed to re-arrange the control points for Non-Uniform Rational B-Splines (NURBS) surfaces. This method led to reliable and accurate m-term computations and therefore improved ship motion and load predictions. Validation studies have been carried out for a hydroelastic model of a frigate. Computed motions and loads were compared with experimental data.
Topics: Stress , Waves , Ships
Commentary by Dr. Valentin Fuster
2017;():V07AT06A005. doi:10.1115/OMAE2017-61146.
It is important to predict the propeller tip vortex flow and its effect on hull vibration and noise. In our previous work, the tip vortex flow of the David Taylor Model Basin (DTMB) 5168 propeller model has been studied based on the Reynolds Averaged Navier-Stokes equation (RANS) solution using various eddy viscosity and Reynolds Stress turbulence models. A set of structural grids were used, however, large Jacobian values of the structural grids around the propeller tip region led to the convergence problem and inaccurate solutions. In the present work, the numerical prediction of the same propeller model was improved by using a steady-state RANS solver simpleFoam in OpenFOAM with locally refined unstructured grid along the tip vortex trajectory. The computed thrust and torque coefficients and the velocity components across the vortex core are compared with experimental data and results in the previous studies. Improvement in the prediction of velocity components across the tip vortex core were achieved.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A006. doi:10.1115/OMAE2017-61199.
The ship wave resistance can be evaluated by two alternative methods after solving the boundary value problem. One is the far field method e.g. Havelock’s formula, and another is the near field method based on direct pressure integration over the wetted hull surface. As is well known, there exist considerable discrepancies between wave resistance results by far field method and by near field method.
This paper presents a Lagally expression in consistency with Havelock’s formula. In order to derive the Lagally expression, the symmetry of Havelock’s Green function is used in the same manner as Yeung et al (2004). Another expression to examine the relation with water pressure integrations or to ensure physical consistency is also derived by slightly deforming that expression. Some numerical comparisons of wave resistance of Wigley, KCS and KVLCC2 models among by Havelock’s formula, some direct pressure integration methods and present two new near field expressions, are shown to demonstrate consistency numerically.
Topics: Waves , Ships
Commentary by Dr. Valentin Fuster
2017;():V07AT06A007. doi:10.1115/OMAE2017-61219.
On-board Energy systems in vessels have to use fuel efficiently to maintain ship speed at lowest possible costs. This paper describes how to use ship operational data to improve and maintain efficiency of the vessel’s power production with respect to the condition and performance of equipment. The paper describes an overview of an automated Technical Operations Performance (TOP) Monitoring service. TOP monitors the performance of marine main and auxiliary diesel engines by use of the information collected onboard vessels at regular intervals. Performance data are stored in xml-reports sent as email attachments from ship to shore. This communication is reliable and cost efficient for merchant ships that are on-line only for shorter periods. Load, ISO and environmental corrections make results valid for benchmarking and trending. The service aggregates the hierarchical information obtained from different sources by transferring measurement readings into unified indicators, the Technical Condition Index (TCI) [1]. Experts manually check the automatically generated performance reports and add additional guidance on options to improve power production and machinery conditions analyzing the available data with respect to different targets, such as low engine degradation and high fuel efficiency. The performance reports then influence business processes indicating possible causes for loss of performance in equipment and possible erroneous instrumentation, and the need for maintenance actions. The obtained TCI values show the performance of individual units, or for a fleet/class of equipment and vessels.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A008. doi:10.1115/OMAE2017-61400.
This paper presents some outcomes from a four years (2013 – 2016) long research project investigating validation of ship specific simulation models. In contrast to the other initiatives such as SIMMAN 2008 [1] and SIMMAN 2014 [2], the R&D project “Sea Trials and Model Tests for Validation of Shiphandling Simulation Models” (SIMVAL [3]) investigates model development and validation methods for specific vessels. For these vessels, the yard’s documentation of manoeuvring characteristic was available for the researchers. In addition, the project has been given permission to perform different sets of sea trials on selected case vessels. As far as possible, these sea trials were designed to document vessel-specific operations such as low-speed manoeuvres and dynamic positioning. Other papers presenting results from the SIMVAL project will be given in a separate session, Session 12–14, in the Torgeir Moan Symposium at OMAE2017.
Topics: Performance , Ships
Commentary by Dr. Valentin Fuster
2017;():V07AT06A009. doi:10.1115/OMAE2017-61860.
There has been a lot of interest in trim optimisation to reduce fuel consumption and emissions of ships. Many existing ships are designed for a single operational condition with the aim of producing low resistance at their design speed and draft with an even keel. Given that a ship will often sail outside this condition over its operational life and moreover some vessels such as LNG carriers return in ballast condition in one leg, the effect of trim on ships resistance will be significant. Ship trim optimization analysis has traditionally been done through towing tank testing. Computational techniques have become increasingly popular for design and optimization applications in all engineering disciplines. Computational Fluid Dynamics (CFD), is the fastest developing area in marine fluid dynamics as an alternative to model tests. High fidelity CFD methods are capable of modelling breaking waves which is especially crucial for trim optimisation studies where the bulbous bow partially emerges or the transom stern partially immerses. This paper presents a trim optimization study on the Kriso Container Ship (KCS) using computational fluid dynamics (CFD) in conjunction with towing tank tests. A series of resistance tests for various trim angles and speeds were conducted at 1:75 scale at design draft. CFD computations were carried out for the same conditions with the hull both fixed and free to sink and trim. Dynamic sinkage and trim add to the computational cost and thus slow the optimisation process. The results obtained from CFD simulations were in good agreement with the experiments. After validating the applicability of the computational model, the same mesh, boundary conditions and solution techniques were used to obtain resistance values for different trim conditions at different Froude numbers. Both the fixed and free trim/sinkage models could predict the trend of resistance with variation of trim angles; however the fixed model failed to measure the absolute values as accurately as the free model. It was concluded that a fixed CFD model, although computationally faster and cheaper, can find the optimum trim angle but cannot predict the amount of savings with very high accuracy. Results concerning the performance of the vessel at different speeds and trim angles were analysed and optimum trim is suggested.
Topics: Containers , Ships
Commentary by Dr. Valentin Fuster
2017;():V07AT06A010. doi:10.1115/OMAE2017-61878.
Station keeping analysis is an important activity in the early stages of any vessel/DP project that eventually determines the machinery and thruster configuration and thruster size selection. In order to obtain reliable results, it is crucial to apply engineering tools that realistically represent the flow physics and resulting hydrodynamic forces. Present computer tools are based on the assumption that wave drift- and current forces can be superimposed. However, there are also mutual interaction effects between waves, current and hulls that should be accounted for in the evaluation of the wave drift forces. In MULDIF, a 3D diffraction/radiation panel code developed by SINTEF Ocean within the framework of a JIP, this wave-current-body interaction is taken into consideration by a new potential flow numerical model. A case study with offshore vessels and general cargo ships of different main dimensions has been performed to assess the capabilities of MULDIF for station keeping purposes in wave and current environments. The first-order vessel motions as well as mean second-order drift forces for 0 kn forward speed without current have been calculated. Through an interface to SINTEF Ocean’s vessel response code VERES, MULDIF offers the possibility to include viscous roll damping due to hull friction, flow separation at bilge keels, lift effects as well as normal forces acting on bilge keels and hull pressure created by the presence of bilge keels. This reduces roll motions to a realistic extent as shown by the comparison of RAOs from MULDIF calculations and model tests. Roll reduction tank effects can currently only be considered through the external damping matrix. Model tests for the selected vessels have been performed in SINTEF’s Ocean Basin in a soft-mooring arrangement in different irregular sea states and headings in deep water. The models were equipped with two two-component force transducers, measuring the x- and y- components of the forces. The yaw moments have been calculated from the y-force measurements. In order to measure the vessel motions in six degrees of freedom, an optoelectronic position measuring system has been used. Selected cases illustrate the significant influence of wave-current interaction on motions and drift forces.
Topics: Waves
Commentary by Dr. Valentin Fuster
2017;():V07AT06A011. doi:10.1115/OMAE2017-61949.
Ships travel in waves most of the time. The horsepower increase or speed loss in waves can become large in adverse sea. Speed loss needs to be compensated for by increasing the power. Moreover, the associated speed-loss can possibly not be compensated due to the limit of installed power. This will cause delays, and may even lead to safety concerns in maneuvering. Thus, there is a need for minimizing added resistance due to both economical and safety reasons. Ships with better performance in waves even with reduced power are desired. Latest researches on advanced ship optimization are taking added resistance into account. Ship bow optimization has been the main measure to reduce added resistance in waves.
Based on analyzing the working principles and potential benefit of the different kinds of novel ship bows, a novel measure is proposed to reduce the ship resistance in waves is proposed. A novel measure to reduce the ship resistance in waves of existing ships by installing a simple structure at the ship bow. The structure is designed to sharpen the ship bow and therefore reduce added resistance due to wave reflection. Thus, it is suitable for the large tankers and bulk carriers, which have blunt bows. The volume above free surface was expected to reduce ship motions and the added resistance due to ship motions consequently. This measure does not change the original ship design. It can be retrofitted on existing ships fairly easily at low cost. In order to verify the benefit due to the retrofitted structure, CFD simulations are performed in both head and oblique waves, which can take 3D effect into account. Four different retrofitted structures are designed and the numerical simulations are performed with the same numerical and mesh settings in each wave condition. The CFD simulation results confirm that the novel measure can reduce ship added resistance efficiently and it also has benefits in oblique waves.
Topics: Waves , Ships
Commentary by Dr. Valentin Fuster
2017;():V07AT06A012. doi:10.1115/OMAE2017-62053.
Parametric resonance (PR) in roll is of concern for fishing vessels, especially in head-sea waves. Here the effect of passive anti-roll free-surface tank is investigated experimentally and numerically on realistic fishing-vessel geometry at zero forward speed. On the numerical side, the onboard tank is simulated using an open source computational fluid dynamic (CFD) development platform, OpenFOAM (Open Field Operation and Manipulation). The internal flow solver is coupled with the seakeeping solver, which is based on the weakly nonlinear method proposed in [1]. Experimentally, two different relevant scenarios were examined: 1) a 2D rectangular tank with shallow-water filling depth was forced to oscillate in roll and the loads induced on the tank were measured; 2) a fishing vessel was tested in a towing tank, prescribing regular head-sea waves. The vessel was examined both without and with anti-roll tanks and a mooring-line system was designed so to control the horizontal motions with limited effect on the parametric occurrence. The experiments on the fishing vessel are considered to assess the seakeeping solver. Both model tests and numerical results confirmed the effectiveness of an on-board tank in avoiding PR. For the examined cases with tank, the parametric resonance did not occur without forcing an initial roll. Moreover, the initial roll amplitude and roll phase relative to the heave motion matter for triggering the instability.
Topics: Resonance , Vessels
Commentary by Dr. Valentin Fuster
2017;():V07AT06A013. doi:10.1115/OMAE2017-62151.
A fast method for optimizing the configuration of a di-hull system is to take advantage of the wave-cut signatures of each hull and evaluate the combined resistance of the hull system using analytical expressions that portray the interference effects of the hull-generated waves. This interference formula is available in Yeung et al. [1] and can be used in conjunction with the wave-cut signatures. The Longitudinal Wave-cut Method (LCM) is utilized to acquire the wave-making spectrum for each monohull. Then the di-hull interference wave resistance is deduced by substituting these experimentally-acquired information into analytical expressions for resistance computation. The pre-acquired wave-spectrum information can be stored and used for a combination of any component hulls, identical or not. This hybridization procedure of theory and experiments is tested and evaluated. Its merits and deficiencies are discussed.
Topics: Waves , Hull
Commentary by Dr. Valentin Fuster
2017;():V07AT06A014. doi:10.1115/OMAE2017-62480.
Numerical simulations are carried out for gap resonance problem between two side-by-side non-identical boxes. The linear potential model over-predicts the resonant amplitude in the narrow gap because it not only neglects the energy dissipation due to vortical motion, but also neglect the nonlinearity due to free surface. More relative energy are reflected with the increase of incident wave amplitude, leading to the decrease of relative resonant amplitude and relative energy dissipation in the narrow gap at resonant frequency. When the incident wave frequency is outside a little band to resonant frequency, relative energy dissipation becomes the dominant factor for the decrease of relative wave amplitude in the narrow gap with the increase of incident wave amplitudes. In a word, both the free surface nonlinearity and fluid viscosity play the important, but different, roles on wave resonances in the narrow gap.
Topics: Resonance , Fluids , Viscosity
Commentary by Dr. Valentin Fuster
2017;():V07AT06A015. doi:10.1115/OMAE2017-62490.
Parametric rolling of a post-Panamax C11 class containership in regular and irregular waves is numerically investigated using body nonlinear time domain methods based on strip theory. The Froude-Krylov and the hydrostatic forces are calculated for the exact wetted surface area under the undisturbed incident wave profile. Two kinds of formulations are used for calculation of the radiation forces. The first one employs a linear radiation force in which the frequency dependent hydrodynamic coefficients are calculated for mean position of the sections at mean water level. The second formulation calculates the hydrodynamic coefficients for the exact submerged depth of ship sections under the undisturbed incident wave profile, and hence called as body nonlinear radiation force. The numerical results from the aforementioned formulations are compared with each other, and also with experimental results obtained from a wave tank in both regular and irregular waves. For all the cases in regular waves, the vulnerability to parametric rolling is clearly identified by the numerical models, even though a few discrepancies are observed in the estimation of the severity (maximum roll angle) of the problem. In this paper, the effects of the linear and body nonlinear radiation forces on the numerical calculation of parametric rolling of a container ship and the ability of the numerical methods to identify parametric rolling are investigated.
Topics: Containers , Waves , Ships
Commentary by Dr. Valentin Fuster
2017;():V07AT06A016. doi:10.1115/OMAE2017-62613.
Dynamic vertical bending moments are determined for a military vessel hull in still water and under head waves, with a weakly nonlinear method. The domain for hydrostatic and undisturbed pressures integration is time-variant and generated with a quad-tree adaptive mesh algorithm, on which exact formulations for pressure on polygonal elements are used. Linear radiation and diffraction pressures, on another mesh superimposed with the aforementioned, are calculated with a frequency domain code. Results are compared with published experimental ones for small and large wave heights.
Topics: Pressure , Stress , Ships
Commentary by Dr. Valentin Fuster
### Ocean Engineering: Advanced Underwater Vehicles and Design Technology
2017;():V07AT06A017. doi:10.1115/OMAE2017-61066.
In this work, we numerically studied the steady swimming of a pufferfish driven by the undulating motion of its dorsal, anal and caudal fins. The simulations are based on experimentally measured kinematics. To model the self-propelled fish swimming, a Computational Fluid Dynamics (CFD) tool was coupled with a Multi-Body-Dynamics (MBD) technique.
It is widely accepted that deformable/flexible or undulating fins are better than rigid fins in terms of propulsion efficiency. To elucidate the underlying mechanism, we established an undulating fins model based on the kinematics of live fish, and conducted a simulation under the same operating conditions as rigid fins. The results presented here agree with this view by showing that the contribution of undulating fins to propulsion efficiency is significantly larger than that of rigid fins.
Topics: Fins
Commentary by Dr. Valentin Fuster
2017;():V07AT06A018. doi:10.1115/OMAE2017-61124.
In this study, the authors developed the dynamic routing algorithm combining an image detection technique to support the optimal route plan of Autonomous Underwater Vehicle (AUV) inspecting an offshore wind farm affected by ocean currents. A modular structure is applied to program design by the graphical language, LabVIEW (Laboratory Virtual Instrument Engineering Workbench). The modular structure is composed of 6-DOF (Six Degrees-of-Freedom) motion module, a self-tuning fuzzy control module, a stereo-vision detection module, and a dynamic routing module. In terms of path planning for inspection, several Pareto frontiers are solved iteratively according to two objectives, namely, cruise time and energy consumption. Performances obtained from MOPSO (Multi-Objective Particle Swarm Optimization) -based dynamic routing algorithm would be in comparison with those from SOPSO (Single-Objective Particle Swarm Optimization) -based dynamic routing algorithm. In addition, selections of fixed weight and dynamic weight of MOPSO-based dynamic routing algorithms would be discussed in the environment with or without ocean currents. Eventually, the image inspection mode is not only beneficial for optimizing feasible routes but it can also identify features of obstacles for positioning.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A019. doi:10.1115/OMAE2017-61170.
This paper presents 3D path tracking simulations and path-following by experimental testing with a small inspection class ROV. The ROV is underactuated, but moves freely in surge, heave and yaw (4 DOF). Paths used are a spiral for path-tracking and a lawnmower pattern for path-following, where both paths are related to a proposed structural setting and a mission. The structure is a cylindrical fishing cage used for fish farming in the aquaculture, and the task is to perform inspection with equipped cameras and sensors while tracking or following the path.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A020. doi:10.1115/OMAE2017-61461.
This paper presents a method for three dimensional dynamic analysis of a complete deep-water Remotely Operated Vehicle (ROV) system. The presented formulation utilizes Euler-Bernoulli beam theory to represent the cable and the Tether Management System (TMS) Module is represented as a rigid body moving in 6 degrees of freedom. The model is applied to a real ROV-system and compared to experimental data collected from deep-water ROV operations. The ability to estimate TMS position, velocity and acceleration (state estimation) is the key feature of this analysis. This is because acoustic positioning may not always be available hence other means of state estimation is needed to ensure safe and efficient operations. Two different ROV-deployments are simulated and show good correspondence with the experimental data, limitations in acoustic positioning is also shown on the basis of signal-loss. Based on simple current estimates and measured surface-ship position, the relative position of the TMS can be estimated with fairly good accuracy. The ability to simulate the ROV system in real time is also an important feature making the procedure feasible to incorporate in controller design. The cable forces are estimated and show that horizontal ship motions are of minor importance with regards to cable tension.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A021. doi:10.1115/OMAE2017-61651.
Floating bodies such as oil rig/production platform and wind turbine in ocean need to be fixed or controlled at expected position by its supporting system which includes tension tendon and catenary mooring-line. Recently, the later one, catenary mooring-line, is increasingly used in deeper water due to its lower cost and easier installment. As the floating platform are developed toward deeper water depth, the length of the mooring-line become larger and consequently the dynamic behaviors such as the structural inertia and hydrodynamic inertia/damping of the mooring-line become more obvious.
In this paper, the dynamic behaviors of the mooring-line are considered, and compared with the traditional quasi-static method where only the static restoring force is involved, so as to comprehensively examine the non-linearly restoring performance of catenary mooring-lines. Firstly, the nonlinear dynamic model of the mooring system is developed based on our 3d dynamic catenary equations along with the modified finite element simulations. Compared with the static restoring force, essentially depending on structural gravity and overall shape based on static catenary theory, the dynamic restoring force is analyzed based on our 3d curved flexible beam approach where the structural curvature changes with its spatial position and time in terms of vector equations. In our modified finite element simulations, the rotation degree of freedom between neighboring beam elements is released and bending stiffness of individual element is set to be zero, and the statically original shape and top tension according to the traditional static catenary theory are used as the initial conditions. Moreover, the hydrodynamic force is loaded as depending on structural motion.
Based on our numerical simulations, the influences of the amplitude and frequency of the catenary’s top-end motion, along with the structural parameters (including the mass density and initial tension ratio), on mooring line’s temporal-spatial evolution of displacement and dynamic tension are studied. Also, the slack-taut phenomenon caused by structural /hydrodynamic inertia and damping are presented. Our results show: 1) Generally, the displacement distribution along the mooring-line is characterized as a stable stand wave. The additional part of restoring tension due to the dynamic effects is up to 20% of the quasi-static method, and the tension amplitude difference (between the maximum tension and minimum tension) is around three times of the quasi-static value. Particularly, as the mooring-line becomes slack, the response is characterized as travelling wave, the maximum tension amplitude is up to 9 times of the static method. 2) As the amplitude/frequency of the catenary’s top-end motion increases, the value of catenary displacement firstly drops and then rises. The displacement distribution along catenary length changes with the motion of top end. Interestingly, the maximum displacements occur at the middle point of the catenary for case of surge while the maximum displacement moves up along the catenary as the top end motion gets larger for case of heave. 3) The magnification factor of top tension drops with increase of mooring-line mass density but rises with the increase of the initial tension ratio. It is also noted the velocity amplitude at higher frequency in the velocity spectrum may increase as the top end motion increases.
Topics: Mooring
Commentary by Dr. Valentin Fuster
2017;():V07AT06A022. doi:10.1115/OMAE2017-61742.
This paper presents a filter for underwater positioning in an aquaculture environment with demanding weather conditions. The positioning system is based on acoustic transponders mounted at a net pen on the sea surface. The transponders are exposed to oscillations due to wave disturbance. This will have an impact on the accuracy of the positioning system. An extended Kalman filter (EKF) solution has been proposed including a wave motion model integrated with the pseudo-range measurements from the transponders. Simulations show that the proposed filter compensates well for the disturbances.
Topics: Wave motion
Commentary by Dr. Valentin Fuster
2017;():V07AT06A023. doi:10.1115/OMAE2017-61773.
A vision based underwater localization system using fiducial markers is proposed. The system is implemented as a new control mode in a shared control system for ROVs and tested experimentally in a pool. A high accuracy underwater motion capture system in the pool is used as ground truth for performance assessment of the proposed system. The main objective has been to assess the feasibility for using a vision system and fiducial markers for localization of an underwater vehicle performing automated manipulation at subsea facilities. This research show that it is feasible to perform autonomous manipulation using the proposed system. The assessment of the performance in a set of experiments show that all degrees of freedom have a an approximate Gaussian error distribution with zero mean. The largest position errors are experienced in the Y-direction. This is seem to be caused by inherent coupling between yaw and lateral position in the camera projection of the fiducial marker and errors in the yaw direction. The main contribution of this paper is an experimental performance assessment of a localization method commonly used for terrestrial robots in a marine environment.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A024. doi:10.1115/OMAE2017-62056.
The present study is focused on performance issues of underwater vehicles near the free surface and gives insight into the analysis of a speed loss in regular deep water waves. Predictions of the speed loss are based on the evaluation of the total resistance and effective power in calm water and preselected regular wave fields w.r.t. the non-dimensional wave to body length ratio. It has been assumed that the water is sufficiently deep and that the vehicle is operating in a range of small to moderate Froude numbers by moving forward on a straight-line course with a defined encounter angle of incident regular waves.
A modified version of the Doctors & Days [1] method as presented in Skejic and Jullumstrø [2] is used for the determination of the total resistance and consequently the effective power. In particular, the wave-making resistance is estimated by using different approaches covering simplified methods, i.e. Michell’s thin ship theory with the inclusion of viscosity effects Tuck [3] and Lazauskas [4] as well as boundary element methods, i.e. 3D Rankine source calculations according to Hess and Smith [5]. These methods are based on the linear potential fluid flow and are compared to fully viscous finite volume methods for selected geometries.
The wave resistance models are verified and validated by published data of a prolate spheroid and one appropriate axisymmetric submarine model. Added resistance in regular deep water waves is obtained through evaluation of the surge mean second-order wave load. For this purpose, two different theoretical models based on potential flow theory are used: Loukakis and Sclavounos [6] and Salvesen et. al. [7]. The considered theories cover the whole range of important wavelengths for an underwater vehicle advancing in close proximity to the free surface. Comparisons between the outlined wave load theories and available theoretical and experimental data were carried out for a submerged submarine and a horizontal cylinder.
Finally, the effective power and speed loss are discussed from a submarine operational point of view where the mentioned parameters directly influence mission requirements in a seaway.
All presented results are carried out from the perspective of accuracy and efficiency within common engineering practice. By concluding current investigations in regular waves an outlook will be drawn to the application of advancing underwater vehicles in more realistic sea conditions.
Commentary by Dr. Valentin Fuster
### Ocean Engineering: Coastal Engineering
2017;():V07AT06A025. doi:10.1115/OMAE2017-61010.
Building design codes in the US do not include any consideration of tsunami design, even though past tsunamis have caused significant structural damage in coastal communities. In February 2011 the American Society of Civil Engineers (ASCE) formed a new Tsunami Loads and Effects subcommittee, which spent four years to develop a new chapter for inclusion in the ASCE7-16 Standard, Minimum Design Loads and Associated Criteria for Buildings and Other Structures. This new chapter has now been approved by the ASCE7 Main Committee and ASCE7-16 has been published with a new Chapter 6, Tsunami Loads and Effects. In December 2016, ASCE 7–16 was officially adopted by the International Code Council, with the new chapter on Tsunami Loads and Effects, for inclusion in the US model code, IBC 2018. The tsunami design provisions will apply to all coastal communities in California, Oregon, Washington State, Alaska and Hawaii. This paper presents an overview of the new ASCE7-16 Tsunami Loads and Effects design provisions and how they were developed based on field survey observations and laboratory experimentation.
Topics: Design , Tsunamis
Commentary by Dr. Valentin Fuster
2017;():V07AT06A026. doi:10.1115/OMAE2017-61206.
This study evaluates the influence of coastal structures on coastal morphology near Hsin-Chu fishery harbor in the northwest of Taiwan. As a result, the downdrift side has undergone local erosion due to the longshore sediment was impounded at updrift breakwaters resulting the enhancement of coastal flood risks as well as deterioration of the biological environment. Process and trend analyses were used to assess the effects the coastal exploitation made on the coastal morphology. Environmentally-friendly remedial measure, beach nourishment is proposed. The sediment source supply and the location of beach nourishment were also suggested for achieving the goal of sustainable use in the area.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A027. doi:10.1115/OMAE2017-61354.
Coastal geomorphology is a complex phenomenon which is governed by nearshore wave and tidal climate. Change in climate indices (like sea surface temperature, sea level, intensified cyclone activity, among others) and climate modes (like El Nino Southern Oscillation (ENSO), Southern Annular Mode (SAM), Indian Ocean Dipole (IOD)) affect the wave climate and modify many coastal processes thereby altering the geomorphology of shorelines. In countries like India where tropical and sub-tropical cyclones are common, the coastal geomorphology is under constant threat. Coasts are also vulnerable to anthropogenic factors like offshore structures, harbours, wave farms and other constructional activities along the shoreline. It is thus necessary to understand the evolution of coastlines under the changing climate scenario. The rapidly growing socio-economic development in south-west coast of India has generated the need to investigate the longshore sediment transport (LST) regime in this region under the influence of variable climate factors like the wave characteristics. The presence of numerous river deltas, estuaries and mud banks makes the situation worse especially during the south-west monsoon season (June-September). The investigation on the contemporary evolution of this coastline has not been undertaken and the knowledge of the climate factors that influence the shorelines of the southern tip of India are unknown. This study attempts to understand the temporal dynamics of the longshore sediment transport in this region.
Topics: Climate , Shorelines
Commentary by Dr. Valentin Fuster
2017;():V07AT06A028. doi:10.1115/OMAE2017-61356.
Strong wind often raises waves and result in the sediment siltation. The navigation of outside waterway of Huanghua Port is seriously influenced by sudden siltation induced by strong wind. Before outside waterway treatment, the return sudden siltation volumes must be determined previously. The point estimation of return values can be obtained by distribution curve fitting, meanwhile, interval estimation can provide ranges of return values under some fix confidence levels. Based on the sequences of annual maximum sudden siltation of Huanghua Port from 1979 to 2003, and by using curve fittings of lognormal distribution and maximum entropy distribution, and maximum likelihood interval estimation method, the point and interval estimations of return sudden siltation volumes are presented. The results given by the maximum entropy distribution have higher precision, so they can be applied as the reference of the treatment of sediment accumulation.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A029. doi:10.1115/OMAE2017-61381.
This paper focuses on design aspects regarding breakwaters for cold climate terminals, in particular, the different types of berm breakwaters, their stability, armour mobility criteria and armour size.
A methodology is analyzed in order to determine the mean weight of the heaviest armour class as a function of wave parameters such as the significant wave height and the mean wave period, both for non-reshaping and reshaping stable berm breakwaters. The influence of the wave period on the stone mass required will be of special importance in the discussion. This methodology will enable us to determine the required median armour weight for a specific wave parameter, being easily able to compare the feasibility of different concepts or availability of the required stone size at the location.
As a case study, the breakwater selection for the Melkøya terminal in the Norwegian Barents Sea, is assessed through a comparison of the necessary armour unit masses for the different berm breakwaters. The armour mobility criteria currently established is reviewed and a recommendation for an updated criterion for the statically stable non-reshaped berm breakwater category is proposed.
Topics: Breakwaters , Design , Climate
Commentary by Dr. Valentin Fuster
2017;():V07AT06A030. doi:10.1115/OMAE2017-62283.
The characteristics of wave breaking over a fringing reef are considered using a set of laboratory experiments and the results are used to develop associated predictive models. Various methods are typically used to estimate the characteristics of nearshore wave breaking, mostly based on empirical, analytical and numerical techniques. Deo et al. (2003) used an artificial neural network approach to predict the breaking wave height and breaking depth for waves transforming over a range of simply sloped bottoms. The approach is based on using available representative data to train appropriate neural network models. The Deo et al. (2003) approach is extended here to predict other characteristics of wave breaking, including the type of wave breaking, and the position of breaking over a fringing reef, as well as the associated wave setup, and the rate of dissipation of wave energy, based on observations from a series of laboratory experiments involving monochromatic waves impacting on an idealized reef. Yao et al. (2013) showed that for such geometry, the critical parameter is the ratio of deep-water wave height to the depth of the shallow reef flat downstream of the position of wave breaking, H1/hs, rather than the slope of the reef. H1/hs, and the wave frequency parameter, Display Formula$fH1/g$, are provided as inputs to the neural network models of the feed-forward type that are developed to predict the above characteristics of wave breaking. The models are trained using the experimental data. The breaker type classification model has a success rate of over 95%, implying that the neural networks method outperforms previously used criteria for classifying breaker types. The numeric prediction model for the dimensionless position of wave breaking also performs well, with a high degree of correlation between the predicted and actual positions of wave breaking. The performance is higher when only the plunging breaker instances are considered, but lower when only the spilling breaker instances are considered. The corresponding neural network models for wave setup within the surf zone and the difference in energy flux between the incident and broken wave have success rates of approximately 89% and 94% respectively. The method may be extended to provide predictive models for consideration of a range of natural coastal conditions, random waves, and various bottom profiles and complex geometry, based on training and testing of the models using representative field and laboratory observational data, in support of accurate prediction of near-shore wave phenomena.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A031. doi:10.1115/OMAE2017-62325.
Based on good simulation results during storm events in 2009, MIKE21 was used to study the extreme water level, current velocity and wave height in Laizhou Bay, China. 95 extreme weather processes during 1988–2012 were simulated. For each event, coupled hydrodynamic and wave modules of MIKE21 was chosen to calculate the maximum water level and current velocity. The Gumbel distribution method, commonly used for estimating return-period values of marine hydrodynamic variables, is adopted in this study. The extreme high water level of 50-year return period in Laizhou Bay can reach 2.6–3.8 m; and that of 100-year return period can be as high as 2.8–4.6 m. The 50-year and 100-year return-period values of current velocity can reach up to about 2.8 m/s and 3.2 m/s respectively, both around the Yellow River mouth. Wave height strongly depends on water depth, water level rise, wind speed and direction. The results provide parameter reference for structure design in the Laizhou Bay.
Topics: Waves , China , Water
Commentary by Dr. Valentin Fuster
2017;():V07AT06A032. doi:10.1115/OMAE2017-62341.
Consolidation is one of the most important processes that are needed to be accounted for in the model of cohesive sediment transport. Previous studies have shown that the consolidation paths for soil elements are not unique at low effective stress (here low effective stress means the effective stress is smaller than a threshold effective stress, which is short as TES and denoted as σb) In this study, a new theoretical constitutive equation for the effective stress of soft mud is derived to describe the non-unique consolidation paths at low effective stress.
Firstly, based on the concept of fractal dimension, the mud flocs are treated as self-similar fractal entities and the relationship between mud floc size and sediment volume fraction is established. Due to the fact that the fractal dimension decreases as the floc size increases, the variation of fractal dimension is accounted for. Based on the self-similar model, the theoretical constitutive equation for the effective stress of soft mud is derived.
The constitutive equation is validated using two data sets obtained from consolidation tests in a settling column for soft clay. At low effective stress, the model results curves follow the data trends and the non-uniqueness of consolidation paths are captured. The model results are also compared with existing numerical results and better agreement is presented especially when η is less than 0.5.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A033. doi:10.1115/OMAE2017-62363.
In this paper, a fully nonlinear Boussinesq model is used to simulate the shoreward propagation of bichromatic wave groups over different fringing reef topographies and the subsequent low-frequency oscillations inside a harbor. Based on a low-frequency wave separation technique, the effects of the reef-face slope and the reef ridge on the bound and free long waves inside the harbor and their relative components under the condition of the lowest resonant mode are systematically investigated. For the given harbor, the given reef ridge and the range of the incident short wave amplitudes and the reef-face slopes studied in this paper, results show that the amplitude of the free long waves inside the harbor increases with the reefface slope, while the bound long waves inside the harbor is insensitive to the variation of the reef-face slope. The existence of the reef ridge can notably restrain the bound long waves inside the harbor when the incident short wave amplitudes are large, while it has little influence on the free long waves inside the harbor.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A034. doi:10.1115/OMAE2017-62476.
A stochastic approach calculating the random wave-induced burial and scour depth of short cylinders and truncated cones on mild slopes is provided. It assumes the waves to be a stationary narrow-band random process and a wave height distribution for mild slopes is adopted, also using formulae for the burial and scour depths for regular waves on horizontal beds for short cylinders and for truncated cones. Examples of results are also provided.
Topics: Waves , Cylinders
Commentary by Dr. Valentin Fuster
2017;():V07AT06A035. doi:10.1115/OMAE2017-62543.
Harbours are important infrastructures for an offshore production chain. These harbours are protected from the actions of sea by breakwaters to ensure safe loading, unloading of vessels and also to protect the infrastructure. One of the important hydrodynamic processes in these regions is the interaction of water waves with permeable breakwaters such as rubble mound breakwaters or berm breakwaters. It is important to study the wave-breakwater interactions in order to have an optimal design of these structures. In current literature, research regarding the design of these structures is majorly based on physical model tests. Empirical formulations are derived based on these test, which can have a relatively narrow range of applicability. In this study a new tool, a three-dimensional numerical model is introduced. Physical and numerical models have limitations that can restrict their independent use. A combined use of both can lead to different forms of improvements: being able to model problems that cannot be modelled by either physical or numerical modelling alone; increasing quality at the same cost or obtaining the same quality at reduced cost.
In this study, the open-source CFD model REEF3D is used to study the design of berm breakwaters. The model uses the Volume averaged Reynolds Averaged Navier-Stokes (VRANS) equations to solve the porous flows. At first the VRANS approach in REEF3D is validated for flow through porous media. A dam break case is simulated for two different porous materials. Comparisons are made for the free surface both inside and outside the porous medium. The numerical model REEF3D is applied to show how to extend the database obtained with purely numerical results, simulating different structural alternatives for the berm in a berm breakwater. Different simulations are conducted with varying berm geometry. The influence of the berm geometry on the pore pressure and velocities are studied. The resulting optimal berm geometry is compared to the geometry according to empirical formulations.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A036. doi:10.1115/OMAE2017-62622.
Salient and tombolo are common features found in the lee of detached breakwaters. The empirical parabolic bay shape equation (PBSE) can be applied when their planform is fully developed, whereas numerical model is required to simulate the dynamic shoreline evolution prior to the planform reaching static equilibrium. This paper reports the excellent performance of PBSE through the comparison with labaratory results and the development of a numerical model for dynamic shoreline change that utilizes the concept of PBSE and equilibrium beach profile. Formulation proposed for sediment transport rate is theoretically compared with that in GENESIS. The governing equation for the combined shoreline response model is based on the one-line beach model, which includes shoreline changes owing to longshore and cross-shore sediment transport. Finally, numerical results reveal, by comparing with an experimental case in the laboratory, that the model is adequate to successively simulating the dynamic evolutions of the shoreline behind a detached breakwater.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A037. doi:10.1115/OMAE2017-62634.
Images of the 2004 Indian Ocean tsunami at landfall shows a leading edge marked by short waves (“fission” waves). These waves appear to be cnoidal in shape and of a temporal and spatial scale in line with the longest swell present in the region, and may interact with the longer waves in the background random wave spectrum. As part of a comprehensive series of experiments, the Large Wave Flume at Oregon State University (USA) was used to generate and measure the properties of cnoidal, random, and combined cnoidal-random wave trains. Both the nonlinear energy transfer characteristics (via bispectral analysis) and dissipation characteristics (via a proxy dissipation function) are studied for all generated wave conditions. It is generally determined that the characteristics of the cnoidal wave dominate the combined cnoidal-random wave signals if the energy of the cnoidal wave is at least equal to that of the random wave.
Topics: Waves
Commentary by Dr. Valentin Fuster
### Ocean Engineering: Computational Mechanics and Design Applications
2017;():V07AT06A038. doi:10.1115/OMAE2017-61164.
In this work, a co-simulation case study of a marine offshore surface vessel in Dynamic Positioning (DP) operation, where the DP-controller is placed on an Arduino® micro-controller, is presented. The reasons for using co-simulation are that it is possible to distribute the model among different cores in one computer as well as among different computing members over a local area network. Also, it is possible to export submodels from different software and connect them together in a common simulation. This enables the use of suited modeling software for different types of dynamical systems, as well as hardware, such as micro-controllers for Hardware-In-the-Loop testing. Such an integrated and open simulation method facilitates the development of new products as well as shortening the iterative process in design phases. As for co-simulation standard, the Functional Mock-up Interface (FMI) for co-simulation will be used in this work, and a communication Functional Mock-up Unit (FMU) that communicates with hardware and handles the signal flow between the hardware and the co-simulation will be developed. In the case study, a DP-controller is implemented on the microcontroller and connected to a filter, a position reference system and an offshore vessel model, all implemented as FMUs in the total co-simulation. For simulation master algorithm, the open source software “Coral”, that was developed in the knowledge building project “Virtual Prototyping of Maritime Systems and Operations” (ViProMa), will be used. The simulation results show that even though the micro-controller is set to communicate with a lower frequency than the rest of the co-simulation submodels, the total c-simulation is stable and produces good results. It also show that the FMI standard facilitates hardware in the loop in the co-simulation, and that the co-simulation master algorithm Coral is suited for such simulation cases.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A039. doi:10.1115/OMAE2017-61625.
Diesel electric propulsion has become industry standard for many marine applications. Typically, a significant part of the operations of vessels with diesel electric propulsion is done with low loads on the motors and generators. However, the efficiency of a drive train is typically only calculated for full load conditions. This underestimates the losses during low load conditions. This article presents modeling methods for the electric drive train, which can be used to estimate the efficiencies, also at low load. The models are established with limited parameter sets, as detailed information about of the components are seldom available. This article compares the estimated efficiency of the generator and motor with the given data from datasheets.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A040. doi:10.1115/OMAE2017-61641.
Numerical simulations of wake flow generated by a surface-mounted square cylinder over a subsequent square cylinder are presented for incompressible low-Re turbulent flow. The behaviors of the square cylinder in the wake flow are investigated. A developed numerical method — Semi-Implicit Method for Pressure-Linked Equations (SIMPLE) is adopted to solve the governing equations in steady state. Turbulence effect is modelled by Reynolds Averaged Navier Stokes (RANS) equations with a standard k-ω turbulence model. The k-ω SIMPLE method is validated by comparison with experimental data. The results show that in wake flow, the square cylinder produces a much weaker wake effect and is subjected to an inverse drag force.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A041. doi:10.1115/OMAE2017-61918.
Dynamic Positioning (DP) capability studies are used to assess if a vessel has sufficient thrust capacity to withstand environmental loads while keeping its position and orientation at a specified set-point or path. These studies are usually performed on ships and other DP-controlled surface vessels; consequently, standards and procedures for these are widely known. In this work, a methodology for conducting a DP capability study for Remotely Operated Vehicles (ROV) is presented. Due to the nature of ROV operations, a DP capability study should include different features that are not common to surface vessels. In this case, an ROV connected to a surface vessel through a tether is considered. During operation, the tether is subject to varying current loads that are accumulated along the water column and transferred to the vehicle. Therefore, the ROVs thrusters must be able to withstand, in addition to its own drag, three-dimensional loads due to three-dimensional currents and umbilical-related loads. To illustrate the methodology, two case studies are considered: the DP capability of an ROV that has to operate in the Colombian Caribbean and an existing ROV operating in the North Sea.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A042. doi:10.1115/OMAE2017-62010.
This paper will present the derivation of dynamic equations describing the motion of a knuckleboom crane for marine vessels. The dynamics will be derived using Lagrange’s equation, the theory of virtual work and generalized forces. Simulations of the unforced and forced system will be carried out to verify the crane behaviour. The work is part of setting up a crane lab at the Norwegian University of Science and Technology, NTNU. The rig will be used as an experimental setup available for both students and researchers and is expected to create a solid foundation for further work regarding crane control. Examples of its application are research on heave compensation and soft landing. However, before the setup can be finished a dynamical model governing the system must be derived in order to construct simple crane controllers. As part of the modeling a step by step method for describing the crane motions will be presented. Using rotation matrices and moving reference frames the position of each point on the crane will be described in an inertial reference frame. An implementation of the model in Matlab’s Simulink will also be shown, along with some simple simulations verifying system behaviour. The main result will be a state space formulation of the crane dynamics, a Simulink model for anticipating crane behaviour and a discussion of some simple simulation scenarios.
Topics: Cranes
Commentary by Dr. Valentin Fuster
2017;():V07AT06A043. doi:10.1115/OMAE2017-62356.
Piping stress analysis is performed by the manipulations of support type, location and pipe arrangement based on many specific design criteria. A classical way to find good engineering solutions satisfying design criteria among lots of combinations is obviously time-consuming work. In field practice, it also highly depends on engineer’s experiences and abilities.
This paper proposes a hybrid method by combining several global search optimization algorithms and predication model generation in order to automatically control the combinations of support types as the engineering solutions. Here, we use some efficient and popular algorithms such as genetic algorithm, swarm intelligence and Gaussian pattern search to develop initial design of experiments. From the set of the initials, we build and update a prediction model by applying machine learning algorithm such as artificial neural network. As a result of using the hybrid method, the engineering solution is sufficiently optimized for the classical solution.
Design variables for this problem are the types of restraints (or the pipe support type). The nonlinearity conditions such as gaps and frictions are also treated as key design variables. Each restraint is initially identified as a binary set of design variables, and transformed to integer numbers to run on the n-dimensional design space. The number of dimension corresponds to the number of pipe supports. Currently, pipe stress analysis problems are divided into a certain size that is enough to run on one computer for project management purpose. If we have bigger system with more design variables to consider, the hybrid machine learning method plays a key role in saving computation time with the help of additional parallel computation technique.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A044. doi:10.1115/OMAE2017-62485.
This study presents the performance investigation of a rudder bulb-turbine device (RBTD), which is designed to recover the rotational energy into torque to drive a generator inside the rudder. The blade of turbine is designed first by using lifting line theory, which is modified by lifting surface theory. The induced velocities between the forward propeller and turbine are obtained through the surface panel method (SPM). Hydrodynamic performance for the system is predicted by using SPM. An iterative calculation method is used until the hydrodynamic performance of the system converges. Through the design of turbine behind propeller of a large container ship, the influence of rotational speed of turbine on hydrodynamic performance of propeller-turbine system is observed. Then the size of rudder bulb is determined by calculating the influence of rudder bulb geometry on the hydrodynamic performance of the propeller-rudder system. Based on CFD technology, the hydrodynamic performance of the propeller-rudder system without/with RBTD is also simulated, and velocity distribution is observed. The results show that RBTD is successfully designed and as a ship energy saving device is feasible.
Topics: Design , Turbines
Commentary by Dr. Valentin Fuster
### Ocean Engineering: Fluid-Structure, Multi-Body and Wave-Body Interaction
2017;():V07AT06A045. doi:10.1115/OMAE2017-61054.
The present paper focuses on modeling of green water loading on an oscillating body using CFD. The vessel motion is calculated a priory using time domain panel method code, then green water impact is computed based on that pre-calculated motion. The finite volume method is used to capture the green water impact, however in order to represent the free surface, volume of fluid method is used. A sophisticated dynamic mesh is used to handle the motion of the vessel in fluid domain. Several examples and case studies are considered to validate the present CFD model as well as to check the effect of global motion on green water loading such as effect of steepness and heading angle on green water impact. Results show that due to the motion, the impact loading phenomena changes significantly and there is a significant change in pressure on the deck after considering the motion effect and it deviates considerably with the results obtained from fixed vessel cases.
Topics: Vessels , Water
Commentary by Dr. Valentin Fuster
2017;():V07AT06A046. doi:10.1115/OMAE2017-61136.
It is important to predict wave impact and structural responses of ship and offshore structures in extreme sea conditions. There are advantages to apply Lagrangian particle methods to simulate highly nonlinear breaking free surface flow and fluid-structure interactions (FSI). In this paper, an improved moving particle semi-implicit (MPS) method was developed to solve the FSI problems. At each time step, the fluid motions and the structural responses are solved. For flow computations, a modified mixed source term method and an improved free surface identification method were adopted to suppress pressure oscillations. Moreover, a particle collision model was used to enhance the numerical stability and avoid nonphysical solutions. The discretized Poisson equations for pressure were solved by a parallel version of the bi-conjugate gradient stabilized method based on the message passing interface (MPI) approach. For structural responses, solids were treated as isotropic elastic particles. Validation studies were carried out for cases of 2D dam breaking and its interaction with a rubber gate. The numerical solutions are in good agreement with experimental data and other published numerical results.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A047. doi:10.1115/OMAE2017-61235.
Experiments have been carried out with a circular cylinder fitted with four different models of flexible shrouds with variable values of structural damping. Shroud models were derived from the geometry of the suppressor called “ventilated trousers”. VIV responses are presented in a range of reduced velocities from 2 to 15 and Reynolds number from 2,000 to 25,000. Influence of structural and hydrodynamic damping is considered and, since the meshes generate more hydrodynamic damping than a bare cylinder, this effect on VIV suppression is analyzed. With the minimal structural damping, the VT mesh reduced about 55% of the amplitude peak of bare cylinder, while the thick-sparse, thin-sparse and thin-dense meshes reduced about 50%, 45% and 50%, respectively. For the case with similar levels of total damping (structural plus hydrodynamic) the same models reduced about 50%, 25%, 40% and 50%, respectively. The results show that the effect of increasing the structural damping has an important role in the VIV suppression of the thick-sparse mesh. For the other models, this effect is less significant.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A048. doi:10.1115/OMAE2017-61288.
In this paper two methods for modelling the damping in a narrow gap are investigated. The first method is called the Pressure Damping Model. This method has been used in studies of wave energy devices. An attractive feature of this model is that the modified input is directly related to the energy dissipation in the gap, which means that if this dissipation is estimated the input to the model can be obtained directly. The idea of the method is to add a pressure input in the gap to suppress the resonant motion. A challenge with the method is that it contains a non-linear term.
The second method is the Newtonian Cooling damping model. The method is based on introducing a dissipation term in the free surface boundary condition. This dissipation term contains a coefficient which is not directly related to the energy dissipation. Hence this method is not so easy to relate directly to the estimated energy dissipation. An advantage with this method is that it is linear and hence can be expected to be more robust.
In the first part of the paper a 2-dimensional problem is investigated using both methods. In addition to the numerical performance and robustness, much focus is put on investigation of the energy balance in the solution, and we attempt to relate both models to the energy dissipation in the gap.
In the second part the Newtonian cooling method is implemented in a 3-dimensional potential flow solver and it is shown that the method provides a robust way to handle the resonance problem. The method will give rise to a modified set of equations which are described.
Two different problems are investigated with the 3D solver. First we look at a side-by-side problem, where the 3D results are also compared with 2D results. Finally, the moonpool problem is investigated by two different 3D solvers, a classical Green’s function based method and a Rankine solver. It is also shown how this damping model can be combined with a similar model on the internal waterplane to remove irregular frequencies.
Topics: Resonance , Damping
Commentary by Dr. Valentin Fuster
2017;():V07AT06A049. doi:10.1115/OMAE2017-61319.
Simulation of marine operations for launch and recovery of bluff bodies such as autonomous underwater vehicles (AUV), remotely operated vehicles (ROV) or subsea templates is traditionally performed in calm to moderate sea conditions. The reason for doing so is partly due to the interaction between the complex dynamic response of an installation vessel, a moving bluff body and the wave kinematics of the rough sea condition. This is in addition to the need for accurate hydrodynamic coefficients that would enable proper simulation and modelling of the launch and recovery process. The key objective of the current methodology is to minimize risks of damage to the vessel and total loss of assets during the deployment and recovery process for marine operations in rough sea conditions.
The aim of this paper is to present the results of experimental and numerical investigation on the prediction of dynamic response of a bluff body during launch and recovery from a surface vessel in rough sea condition. Experimental measurements of hydrodynamic coefficients and responses of a large scale bluff body using a scaled model were completed. Further studies using a time-domain numerical tool have been undertaken to measure the response characteristic of bluff bodies in rough seas. The study also predicted the contributions of vessel motion in rough seas to the dynamic response of the bluff bodies. The results obtained have shown that simulation of launch and recovery operations in rough seas can be carried out efficiently if their hydrodynamic coefficients through the wave active regions of the rough seas are predicted and then adequately implemented in the simulations.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A050. doi:10.1115/OMAE2017-61322.
The objective of this study was to develop a model for predicting spray droplet size and velocity distributions during spray cloud formation arising from a wave impact with an object. The study looked at scaling issues and developed a scaling model to relate the spray characteristics measured in a tow tank to large-scale spray formations arising from wave impact with vessels. Several phenomena related to spray scaling have been studied to develop the scaling rules in large enclosures. These are wave theories for deep water, air entrainment process during the wave impact, water sheet disintegration and droplet size distribution as well as the scaling of two-phase flow interfaces (water/air). The focus of this study was on atomization and particle motions, and the thermodynamic part of scaling was ignored. The formation of upstream droplets caused by a wave impact on the bow of a vessel is the result of sheet and droplet breakup. Scaling models related to the process of air entrainment, which is caused by the wave impact, water sheet breakup, and spray cloud formation, were investigated to implement a comprehensive scaling model. A mathematical formulation, considering the aforementioned phenomena, was developed to calculate the final average droplet diameter and maximum run-up velocity. The effects of initial wave characteristics, the geometrical characteristics of the water sheet at the moment of water impact, and a spray parameter, on the final average droplet diameter were investigated. Predictions of wave characteristics and final droplet diameter are compared with previously published field observation data.
Topics: Waves , Drops , Sprays
Commentary by Dr. Valentin Fuster
2017;():V07AT06A051. doi:10.1115/OMAE2017-61327.
This paper presents the applications of an efficient hybrid time-domain simulation model for predicting moored Sevan-floater motions in irregular waves and finite water depth. The irregular incident waves are modeled by the extended Boussinesq equations, which can capture wave-wave interactions and the low-frequency long waves accurately in finite and shallow water depth. By imposing the incident wave kinematics on the surface of the floater, a panel model based on Rankine source method is applied for the calculation of wave forces and corresponding floater motions. The contributions from low-frequency components in incident waves as well as their diffraction effects are included in the wave force calculations. Validation of the irregular waves simulated by the present numerical model are performed against experimental data. Then, the simulated moored floater motions are compared with model test results and results based on Newman’s approximation. The general good agreements with experimental results demonstrate the present model can be used as an alternative for this problem while Newman’s approximation shows non-conservative results.
Topics: Mooring , Water
Commentary by Dr. Valentin Fuster
2017;():V07AT06A052. doi:10.1115/OMAE2017-61528.
This paper is inspired by a recent numerical study (Shoele and Zhu, 2012, “Leading edge strengthening and the propulsion performance of flexible ray fins,” Journal of Fluid Mechanics, Vol. 693, pp. 402–432), which shows that, for a 2D flexible ray replicating the pectoral fins of live fish, undergoing a flapping motion in a viscous fluid, the performance can be significantly improved via the flexibility distribution on the rays. In present study, we investigate the propulsion capability of a 3D caudal fin undergoing a flapping motion. The embedded rays are modeled as linear springs and the soft membrane is modeled as a flexible plate being able to deform in span-wise direction. A finite-volume method based Navier-Stokes solver is used to solve the fluid-structure interaction problem. The present paper focuses on the effects of various distributions of the ray and the ray flexibilities, which can lead to different fin deformations. It is shown that the detailed ray distribution has significant influence on the propulsion performance. By distributing fin rays at the tips rather than the middle of fin, a less power expenditure is observed, leading to higher propulsion efficiency. However, larger thrust force is obtained through distributing the rays at the middle, which is attributed to larger effective flapping amplitude. Additionally, ray flexibilities also play a pivotal role in the thrust generation of the fin.
Topics: Propulsion
Commentary by Dr. Valentin Fuster
2017;():V07AT06A053. doi:10.1115/OMAE2017-61553.
In this study, a series of validations of a weakly one-way CFD-FEA coupling method for the estimation of the dynamic response of a container ship under severe wave condition is made. By comparing the prediction with linear/non-linear strip method, 3D panel method and towing tank test results under various wave conditions in terms of rigid body motions and structural loads, the effectiveness of the CFD-FEA coupling method is confirmed. Furthermore, the hydro-elastic behavior obtained by 3D panel method and the CFD-FEA coupling method are validated regarding the whipping moment by comparing the experiment.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A054. doi:10.1115/OMAE2017-61591.
Wave and current loads on offshore structures are an important factor in the design of offshore structures. These forces are usually evaluated by semi-empirical Morison equation for tubular members wherein the ratio of characteristic dimension to wavelength is less than 0.2. In many cases, offshore structures such as jackets will have appurtenances such as anodes fitted on to them for various purposes, which may not contribute to the overall stiffness. However, these items will contribute to the wave and current loads in the order of magnitude of 10 to 20%. The calculation of hydrodynamic loads on such singular tubular members fitted with appurtenances can be done by taking to account their contribution towards drag and inertia. However, for complex structures, such as jacket structures with numerous members, it becomes practically very difficult and time consuming to do this calculation. In the industry, the general practice is to increase the overall loading due to presence of anodes by around 10 to 20%, based on experience and thumb rules.
This paper focuses on the evaluation of wave loads on jackets due to the presence of anodes on jacket legs and braces, and comparing them to that of a jacket without anodes. The evaluation of wave loads is done by both numerical modelling and theoretical evaluation. The numerical model is based on frame analysis using SACS software which has the facility to simulate the wave load on space frame structures. Three different anode-to-jacket weight ratios (total weight of anode to total weight of jacket) are considered. The anodes are modelled as per design requirements and distributed throughout the structure. Recommended hydrodynamic coefficients from codal provisions are used. The overturning moments and base shear are evaluated for design regular waves and current. Results are presented in terms of comparison of base shear and overturning moment to ensure consistency, for three different cases. The recommendations for design engineers within the depth range and region studied can be drawn from this study.
Topics: Anodes , Stress , Waves
Commentary by Dr. Valentin Fuster
2017;():V07AT06A055. doi:10.1115/OMAE2017-61682.
To study the hydrodynamic characteristics of the submersible mussel raft in waves and currents, the numerical model of the submersible raft was established based on the finite element method and kinematics theory. The finite element program Aqua-FE™ was applied to simulate the impacts of waves and currents on the hydrodynamic responses of the surface and submerged rafts, respectively. Morison Equation was applied to compute the tension of the mooring lines. Apart from the wave condition, the flow has a significant effect on the mooring line tension of the submersible raft. The submerged raft is useful for reducing the mooring loads. The submergence depth of the mussel raft can be adjusted depending on the marine environment. The results show that the submerged raft wave response was found to be reduced relative to the surface raft. The vertical motion of mussel rope connection points was significantly reduced by submergence, resulting in reduced potential for mussel drop-off. Compared the performance of the submerged raft in the same condition, the motion amplitude of the framework of the raft decreased significantly while increasing the submergence depth. At the same period, the trend of the decrease followed by levelling off with an increasing wave height. However, the submergence depth had no significant effect on the mooring line tension.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A056. doi:10.1115/OMAE2017-61787.
This work deals with an experimental and numerical study on the horizontal and vertical hydrodynamic forces induced by tsunami-like waves on horizontal cylinders. The laboratory investigation has been performed in the wave flume of the University of Calabria. Twelve pressure transducers have been mounted along the external contour of a cylinder, while four wave gauges have been located close to the cylinder and an ultrasonic sensor behind the paddle to measure its displacement. Tests have been carried out for Keulegan-Carpenter numbers, KC, ranging from about 4 to 7. By the numerical viewpoint, a diffusive weakly-compressible SPH model has been adopted. To prevent spurious flows near the cylindrical contour, a packing algorithm has been applied before SPH simulations. The acoustic components occurring in the numerical pressure field have been filtered through the application of Wavelet Transform. By using different calibration methods, experimental and SPH forces and kinematics at the cylinder have been used to calculate the hydrodynamic coefficients in the Morison and transverse semi-empirical equations for engineering purposes.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A057. doi:10.1115/OMAE2017-61852.
In this paper an existing time domain panel method, which was originally developed for propeller flow simulations, is extended by implementing the mixed Eulerian-Lagrangian approach for the computation of the non-linear free water surface. The three-dimensional panel method uses a constant source and doublet density distribution on each panel and a Dirichlet boundary condition to solve the velocity potential in every time step. Additionally, a formulation for the acceleration potential is included in order to determine the hydrodynamic forces accurately. The paper gives an overview on the governing equations and introduces the numerical approach. Validation results of the developed method are presented for the wave resistance of a submerged spheroid and a wigley hull. Additionally, the wave diffraction due to a surface piercing cylinder in regular waves is validated regarding the forces and the water surface elevation around the body. Here, the computations are compared with other numerical methods as well as tank test results. Apart from this, the paper deals with an application example showing simulations of an artificial service vessel catamaran in waves. The forces on the hull with and without forward speed are presented. The paper concludes with a discussion of the presented results and a brief outlook on further work.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A058. doi:10.1115/OMAE2017-61867.
When floating structure with internal fluid compartment is close to other structures, the multibody interaction problem needs to be addressed in addition to the internal fluid influence. Furthermore, shallow water effects become important, especially when the gap between the floating structure and the sea floor is small. These issues are encountered when designing a novel floating oil storage facilities in nearshore area. To investigate these issues, floating models under 1:50 scale are built to perform model tests.
The test set-up uses a set of flexible constraints working as fenders placed on frames to restrain the motions of the models in the horizontal plane. Various tests in waves are carried out to measure motion responses of single model in waves with different filling levels and stiffness of “fenders”. The reaction forces on the “fenders” are also measured. Several regular wave conditions are selected to perform tests on double model system to investigate multibody interactions under the influence of internal fluid and effects of waves between the tanks. The drag forces for both single model and double models are measured by performing model tests under constant current from different directions, to check the shielding effects. The tests are performed in shallow-water wave basin, and the constant currents tests are performed by towing the models in a flume tank. Both facilities are located at National University of Singapore (NUS).
This paper presents the detailed setting of the model tests. The single model’s RAOs with 20% filling level of internal fluid are given to demonstrate the influence of internal fluid on the motions. The performances of a single tank, including six DOF motions are shown. The results will be used for validation of numerical analysis results in the near future.
Topics: Fluids , Storage tanks
Commentary by Dr. Valentin Fuster
2017;():V07AT06A059. doi:10.1115/OMAE2017-61948.
Three-dimensional numerical simulation of regular waves passing over cylindrical monopile has been conducted to investigate the vortex dynamics. To do so the rectangular wave flume and monopile is modeled on a solver, available in the open-source CFD toolkit OpenFOAM®. The solver applied RANS equations with VOF method for tracking free surface. Model validation has been done by comparison numerical results with the experimental ones and admissible agreement has been seen. Computations have been done for three cases with different pile diameters consequently for different Keulegan-Carpenter numbers (KC).
The vorticity field around the pile was investigated as well as vortices by means of Q criterion. It was seen that by increasing KC number, horseshoe vortices will be formed and vortex shedding will be happened. Moreover, Bed shear stress around the pile has been extracted and it has been seen that, the bed shear stress is influenced by KC value which result of existence of horseshoe vortices and vortex shedding.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A060. doi:10.1115/OMAE2017-61966.
We consider a comprehensive mathematical and numerical strategy to couple water-wave motion with rigid ship dynamics using variational principles. We present a methodology that applies to three-dimensional potential flow water waves and ship dynamics. For simplicity, in this paper we demonstrate the method for shallow-water waves coupled to buoy motion in two dimensions, the latter being the symmetric motion of a crosssection of a ship. The novelty in the presented model is that it employs a Lagrange multiplier to impose a physical restriction on the water height under the buoy in the form of an inequality constraint. A system of evolution equations can be obtained from the model and consists of the classical shallow-water equations for shallow, incompressible and irrotational waves, and relevant equations for the dynamics of the wave-energy buoy. One of the advantages of the variational approach followed is that, when combined with symplectic integrators, it eliminates any numerical damping and preserves the discrete energy; this is confirmed in our numerical results.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A061. doi:10.1115/OMAE2017-62002.
The motions of floating moored structures are affected by first order wave loads which are proportional to the wave amplitude and associated with the wave frequency. On the other hand, second order wave loads are proportional to the square of the wave amplitude and related to the sum or difference of a pair of frequencies of the irregular sea. Although the second order loads are usually smaller compared to the first order loads, these loads can excite resonance motions in frequencies that the system has very low damping. Therefore, second order wave loads have particular importance in the design of mooring systems.
The multi-body system composed by Tension Leg Platform (TLP) and Tender Assisted Drilling (TAD) is particularly susceptible to the second order effects, due to the very low natural frequencies of their horizontal modes and the very high natural frequencies of the vertical modes of the TLP.
This work presents a numerical study of second order wave loads on the TLP-TAD multi-body system. An extensive hydrodynamic analysis focus on the hydrodynamic interactions between the floaters and how these effects modify the second order loads on the platforms was performed. The second order quadratic transform functions (QTFs) were evaluated using the indirect and the direct method. Moreover, the importance of the free surface integral was checked. Finally, the accuracy of Newman approximation for the low-frequency QTF was evaluated.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A062. doi:10.1115/OMAE2017-62070.
In this work, the solitary wave loads on a submerged horizontal circular cylinder are studied by comparing new analytical results with ad-hoc experimental data. The proposed analytical solution has been recently proposed by Gurnari and Filianoti (2017) and represents an extension of the formulation developed by Filianoti and Piscopo (2008) to assess the solitary wave loads acting on a submerged breakwater and tested in a wave flume on a small-scale model (Filianoti and Di Risio, 2012). Here we deal with a submerged horizontal cylinder following the concept that a solitary wave is subjected to a slowdown passing over a submerged cylinder. A laboratory investigation was addressed to calibrate the adopted semi-analytical method. The speed of the solitary wave celerity crossing the solid submerged cylinder was measured for several wave amplitudes. In the adopted wave flume at the University of Calabria equipped by a piston-type wavemaker, an horizontal cylinder with diameter D = 0.127 m was posed with its center at a depth of 0.2 m. Twelve transducers measured the instantaneous pressures along the external contour of the body. A battery of wave gauges measured the free surface elevation to evaluate the celerity crossing the equivalent water cylinder. Tests confirmed the existence of the slowing down of the celerity of the wave pressure. In other words, we found that the pressure wave is nearly double the time necessary to cross the cylinder with respect to the time necessary to cover the same distance in the undisturbed field, for solitary waves amplitudes ranging from about 0.08 and 0.19 times the water depth. The slowing down increases the horizontal wave force on the solid body with respect to the Froude-Krylov one. Moreover, it appears that in the adopted experimental range the wave force is essentially inertial if compared to the drag one, enabling us to rely upon a simplified analytical model to obtain an effective estimate of the horizontal force produced by a solitary wave on a cylinder.
Topics: Stress , Waves , Flumes , Cylinders
Commentary by Dr. Valentin Fuster
2017;():V07AT06A063. doi:10.1115/OMAE2017-62075.
The physical level of interaction between fluid and structure can be either one-way or two-way depending on the direction of information exchange at the interface of fluid and solid. The former can be solved by a partitioned approach and weak coupling. In problems involving two-way fluid-structure interaction, using a partitioned approach and strong coupling, sometimes stability restriction is encountered. This is an artificial added mass effect, which is independent of the numerical time step. Unfortunately an accurate and efficient method to deal with all the different levels of interaction is scarce. Conventionally, relaxation is applied to remedy this problem. The computational cost is directly related to number of sub-iterations between fluid and structural solver at each time step. In this study, the source of this instability is investigated. A discrete representation of a basic added mass operator is given and instability conditions are assessed. A new method is proposed to relax this restriction, the idea essentially is to remove the instability source from the structure and move it to the fluid and solve it monolithically with the fluid. We call this an interaction law. An estimate of the structural response is derived from structural mode shapes. As a test case, a 2D dam break problem interacting with an elastic vertical flexible beam is selected. The interaction of fluid with the beam undergoes several stages. The breaking waves on the beam can increase the added mass drastically, therefore the added mass ratio increases as well. In such a cases, the asset of interaction law is better elaborated, while the stability condition requires very high relaxation without interaction law, but the relaxation can be lowered by only using first five beam mode shapes. As a consequence, the number of sub-iterations reduces by one order. The numerical observations confirm the reduction in computational time due to utilization of the interaction law.
Topics: Fluids , Mode shapes
Commentary by Dr. Valentin Fuster
2017;():V07AT06A064. doi:10.1115/OMAE2017-62083.
Several authors have studied the solitary wave load on a submerged horizontal cylinder. In the present work, a semi analytical expression of the horizontal force exerted by a solitary wave on a horizontal cylinder is derived. The formula is based on the speed drop factor ƒr, that is the ratio (greater than one) between the time needed by the wave pressure to cross the solid body and the travel time across a transparent cylinder. The ƒr, is calculated numerically by means of the Boundary Element Method on assuming that a solitary wave and a periodic wave having the same wavelength undergoes the same slowing down. (Clearly the wavelength for the solitary wave is estimated approximately.) Abaci for the ƒr, as a function of the ratio between the diameter and the wavelength, for assigned A/d (= amplitude of the solitary wave / bottom depth) have obtained. In order to check the appropriateness of BEM, we carried out an experiment in a numerical wave flume, using the Computational Fluid Dynamics (CFD) technique.
Topics: Waves , Cylinders
Commentary by Dr. Valentin Fuster
2017;():V07AT06A065. doi:10.1115/OMAE2017-62113.
Green water occurs when an incoming wave exceeds the freeboard and propagates on the deck of naval/offshore structures, such as FPSO’s and platforms. The water on deck can affect the integrity of facilities and equipments installed on it, compromise the safety of the crew and affect the dynamic stability of the structure. Traditionally, regular or irregular waves generated by different types of wave-makers have been used to reproduce green water events. This is a good practice to study consecutive events. However, to study isolated events, an alternative could be the use of the wet dam-break approach to generate the incoming flow. The purpose of this paper is to investigate experimentally the use of the wet dam-break approach to generate isolated green water events. Tests were carried out in a rectangular tank with a fixed structure. Different freeboard conditions were tested for one aspect ratio of the wet dam-break (h0/h1 = 0.6). High speed cameras were used to investigate the initial phases of green water. Results demonstrated the ability of this approach to represent different types of green water events.
Topics: Dams , Water
Commentary by Dr. Valentin Fuster
2017;():V07AT06A066. doi:10.1115/OMAE2017-62193.
Water breakup affects the variety of droplet sizes and velocities in a cloud of spray resulting from a sea wave striking a vessel bow. The Weber and Reynolds numbers of droplets are the main parameters for water breakup phenomena. “Stripping breakup” is a faster phenomenon than “bag breakup” and occurs at higher velocities and with larger diameters of droplets. A water breakup model employs droplet trajectories to develop a predictive model for the extent of spray cloud. The governing equations of breakup and trajectories of droplets are solved numerically. Stripping breakup is found as the major phenomenon in the process of the formation of wave-impact sea spray. Bag breakup acts as a complementary phenomenon to the stripping breakup. The extent of the spray as well as wet heights, for a Mediumsized Fishing Vessel (MFV), are obtained by numerical solutions. The results show that bag breakup occurs at higher heights. In addition, there is no breakup when droplets move over the deck.
Topics: Sprays , Vessels , Water
Commentary by Dr. Valentin Fuster
2017;():V07AT06A067. doi:10.1115/OMAE2017-62227.
Hydroelastic response of Very Large Crude Carrier (VLCC), such as springing and whipping, is very important for the fatigue strength analysis. In the present paper, numerical simulation and model test are conducted simultaneously on the springing responses of a 350,000DWT VLCC. The numerical simulation results are obtained by combining 2-D strip method and 3-D Finite Element Method (FEM) in the frequency domain. Meanwhile, the segmented model tests are conducted in three conditions. Additionally, the experimental time histories of wave bending moments in regular and irregular waves are presented. In conclusion, the methods and results presented in this paper have shown that the springing would be much easier when the VLCC is in ballast condition or the full loading conditions with reduced stiffness. The springing response will happen, when the wave encounter frequency is near to the half and one third of the ship’s flexural natural frequency. The numerical method presented is available for springing response analysis quickly with acceptable accuracy.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A068. doi:10.1115/OMAE2017-62321.
Accurate computation of the drift forces and moments is required to study the higher order steady excitations on the floater in waves. One of the components of the drift forces and moments is regarding the relative wave elevation. To obtain this term, we need an accurate estimation of the wave elevation. If the field point is exactly on the waterline, we will encounter some difficulty to get the potential value.
This paper will provide a more accurate method to calculate the wave elevation around the body and discuss the mathematical justifications. The accuracy will be validated by the comparison against the commercial software. When using more panels in the commercial software, the results will converge to those from our in-house program. We observe a large discrepancy in the relatively higher frequency range. The sharp spikes in the original method are not observed in the improved method. Therefore it is necessary to adopt the proposed method in order to provide more reasonable predictions of the mean drift forces.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A069. doi:10.1115/OMAE2017-62322.
We study the multi-body problems with a nonzero speed or with current-wave interactions using the Green function method. The two problems are equivalent when the current is along the longitudinal direction of the ship.
The formulations of a single ship for the zero-speed and nonzero-speed cases are derived. The concepts, the motivations and the assumptions are explained. We also provide the derivations of the added mass and damping for the asymmetric ship profile. Then we extend the conclusions to the multiple ships and formulate the multi-body problems. The in-house program MDL Multi DYN is validated through the study of two Wigley hulls with zero speed in waves. After that, the results for two moving Wigley hulls are generated. The two ships are assumed to advance in parallel at the same speed. Finally, the effects of the separation distances and the different speeds are discussed.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A070. doi:10.1115/OMAE2017-62355.
Vortex-induced motions (VIM) of offshore floaters occur when the frequency of the vortex shedding is close to the natural frequency in the transverse direction of the unit subjected to the current, and this can severely affect the fatigue life of mooring lines and risers. Literatures in recent years have shown an increasing interest in the VIM behavior of semi-submersibles (SS), the geometry of which implies a more complex VIM phenomenon. In the case of multi-column semi-submersibles, the vortices shed around each column. Thus the shape of the columns, circular or square, and the wake interference different for each current heading, characterize the VIM of the unit.
Based on verification by the VIM towing tests for a semi-submersible with four rounded square columns, VIM simulations were conducted using CFD method in the model scale for four semi-submersibles with different column designs: a SS model with four rounded square columns (SRC-SS), a SS model with four circular columns (CC-SS), a SS model with two tandem rounded square columns and two tandem circular columns (SRCT-CCT-SS), and a SS model with two staggered rounded square columns and two staggered circular columns (SRCS-CCS-SS). The current headings ranged from 0° to 180° and reduced velocities of 4 up to 14 were considered.
Different semi-submersibles present different VIM performances owing to the influence of the column design. The most significant transverse motions of the CC-SS model occur at the 0° current heading with the largest nominal transverse amplitudes around 74% of the column diameter. On the other hand, the maximum amplitudes in the transverse direction of the SRC-SS model, approximately 63% of the column width, are observed at the 45° current heading. Additionally, the VIM responses could be mitigated when the semi-submersible consists of combined circular-section and square-section columns.
Commentary by Dr. Valentin Fuster
2017;():V07AT06A071. doi:10.1115/OMAE2017-62391.
Experimental impact tests were performed using a shock machine and aerated water by means of an air-bubble generator. High speed shock test machine allows carrying out tests of impact on water (slamming). This machine permits to stabilise velocity with a maximal error equal to 10% during slamming tests. The air volume fraction in the bubble was measured by optical probe technique. The present work is aimed at quantifying the effects of the aeration on the hydrodynamic loads and pressures during the entry of a rigid body at constant speed in an air-water mixture. The impact tests were conducted with a rigid pyramid for an impact velocity equal to 15 m.s−1 and for two average void fractions, 0,46% and 0,84%. The reduction of the impact force and pressure due to aeration has been confirmed by these experiments.
Topics: Impact testing , Water
Commentary by Dr. Valentin Fuster
2017;():V07AT06A072. doi:10.1115/OMAE2017-62445.
In impacts of breaking waves on offshore structures, it is still not well-known how the air entrainment phenomenon affects the exerted loads. In this paper, a developed CFD solver capable of simulating the air entrainment process was employed to reproduce an experimental investigation on the impact of a spilling wave against a circular cylinder. The exerted in-line force was computed with and without the inclusion of dispersed bubbles. Results showed that the magnitude of the computed force was affected when the entrainment of bubbles was simulated.
Commentary by Dr. Valentin Fuster | {"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": 0.7280368804931641, "perplexity": 1443.2378529279572}, "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-2018-30/segments/1531676590711.36/warc/CC-MAIN-20180719070814-20180719090814-00392.warc.gz"} |
http://math.stackexchange.com/questions/255719/geometric-interpretation-of-h-1p-f-d-1p-d-for-a-polytope | # Geometric Interpretation of $h_1(P)=f_{d-1}(P)-d$ for a polytope
In our lecture "Discrete Geometry 1", we are examining lineare realtions between the components of the f-vector and the h-vector of a polytope, in particular the Euler-Poincaré formula and the Dehn-Sommerville Equations. We already proved that there are no more such relations characterising a polytope.
I am working on the following exercise: Give a geometric interpretation of $$h_1(P)=f_{d-1}(P)-d$$
This is, I choose some linear function in general position $c:\mathbb{R}^d\rightarrow\mathbb{R}$ and order the vertices of $P$ according to the value under this function. The number $h_1(P)$ gives all vertices that have exactly one neighbour according to this ordering. From lecture, we know that the number $h_1(P)$ does not depend on the choice of the function $c$.
Hence, this equation tells me that the number of vertices of a polytope P, that has exactly one neighbour according to the ordering described above, is equal to the number of facets of $P$, minus the dimension $d$.
I did draw some polytops and in 2D, a triangle and a square satisfy this equation, in 3D a tetrahedron satisfies it.
But my question is: How can I give a general interpretation, for I do not see any similarities between the triangle, the square and the tetrahedron that hold for any polytops satisfying this equation.
Thank you for reading through this and thanks for any help, Martin
- | {"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": 0.9415555000305176, "perplexity": 183.69342952332153}, "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-2016-18/segments/1461860118807.54/warc/CC-MAIN-20160428161518-00161-ip-10-239-7-51.ec2.internal.warc.gz"} |
http://mathhelpforum.com/algebra/63723-geometric-progression.html | 1. ## Geometric progression
anyone can understand this question??
a house buyer borrows rm50k from a bank to buy a house which costs rm70k. the rate of interest charged by the bank is 9% per annum, and is calculated based on the amount outstanding at the beginning of each year.the house buyer is required to repay his loan in monthly instalments for a period of 15 years. assuming that the rate of interest is fixed for the entire duration of the loan, find the amount per month he has to repay the bank
answer given :rm516.92 . math topic :geometric progression
2. Originally Posted by qweiop90
anyone can understand this question??
a house buyer borrows rm50k from a bank to buy a house which costs rm70k. the rate of interest charged by the bank is 9% per annum, and is calculated based on the amount outstanding at the beginning of each year.the house buyer is required to repay his loan in monthly instalments for a period of 15 years. assuming that the rate of interest is fixed for the entire duration of the loan, find the amount per month he has to repay the bank
answer given :rm516.92 . math topic :geometric progression
let the monthly repayument be $x$, then the amount repaid in a year is $12x$.
So if $p_1$ is the oustanding debt at the start of a year the outstanding debt at the start of the following year is:
$p_2=(p_1-12x) 1.09$
The next year:
$
p_3=(p_2-12x) 1.09=p_1 1.09^2-12x 1.09^2-12x 1.09
$
Proceeding in this way the debt after 15 years is:
$
p_{15}=p_1 1.09^{15} - \sum_{i=1}^{15} 12x 1.09^i=p_1 1.09^{15} - 12x \sum_{i=1}^{15} 1.09^i
$
CB | {"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": 6, "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": 0.24889561533927917, "perplexity": 1083.1546829964368}, "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-2017-30/segments/1500549426161.99/warc/CC-MAIN-20170726122153-20170726142153-00584.warc.gz"} |
https://fuchsia.googlesource.com/third_party/vulkan-cts/+/a62bc26741eb7156d06798b433c4231da22f12bd/external/vulkancts/modules/vulkan/renderpass/vktRenderPassSparseRenderTargetTests.hpp | blob: be6a840b4edc55e722d96b86c4d65de2c86bd092 [file] [log] [blame]
#ifndef _VKTRENDERPASSSPARSERENDERTARGETTESTS_HPP #define _VKTRENDERPASSSPARSERENDERTARGETTESTS_HPP /*------------------------------------------------------------------------- * Vulkan Conformance Tests * ------------------------ * * Copyright (c) 2017 Google Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * *//*! * \file * \brief Tests sparse render target. *//*--------------------------------------------------------------------*/ #include "tcuDefs.hpp" #include "tcuTestCase.hpp" namespace vkt { tcu::TestCaseGroup* createRenderPassSparseRenderTargetTests(tcu::TestContext& testCtx); tcu::TestCaseGroup* createRenderPass2SparseRenderTargetTests(tcu::TestContext& testCtx); } // vkt #endif // _VKTRENDERPASSSPARSERENDERTARGETTESTS_HPP | {"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": 0.8641864061355591, "perplexity": 27707.64640506151}, "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-2023-06/segments/1674764499654.54/warc/CC-MAIN-20230128184907-20230128214907-00845.warc.gz"} |
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## Four flavors of Schur-Weyl duality
If $V$ is a finite-dimensional complex vector space, then the symmetric group $S_n$ naturally acts on the tensor power $V^{\otimes n}$ by permuting the factors. This action of $S_n$ commutes with the action of $\text{GL}(V)$, so all permutations $\sigma : V^{\otimes n} \to V^{\otimes n}$ are morphisms of $\text{GL}(V)$-representations. This defines a morphism $\mathbb{C}[S_n] \to \text{End}_{\text{GL}(V)}(V^{\otimes n})$, and a natural question to ask is whether this map is surjective.
Part of Schur-Weyl duality asserts that the answer is yes. The double commutant theorem plays an important role in the proof and also highlights an important corollary, namely that $V^{\otimes n}$ admits a canonical decomposition
$\displaystyle V^{\otimes n} = \bigoplus_{\lambda} V_{\lambda} \otimes S_{\lambda}$
where $\lambda$ runs over partitions, $V_{\lambda}$ are some irreducible representations of $\text{GL}(V)$, and $S_{\lambda}$ are the Specht modules, which describe all irreducible representations of $S_n$. This gives a fundamental relationship between the representation theories of the general linear and symmetric groups; in particular, the assignment $V \mapsto V_{\lambda}$ can be upgraded to a functor called a Schur functor, generalizing the construction of the exterior and symmetric products.
The proof below is more or less from Etingof’s notes on representation theory (Section 4.18). We will prove four versions of Schur-Weyl duality involving $\mathfrak{gl}(V), \text{GL}(V)$, and (in the special case that $V$ is a complex inner product space) $\mathfrak{u}(V), \text{U}(V)$.
Let $G$ be a group and let
$\displaystyle V = \bigoplus_{n \ge 0} V_n$
be a graded representation of $G$, i.e. a functor from $G$ to the category of graded vector spaces with each piece finite-dimensional. Thus $G$ acts on each graded piece $V_i$ individually, each of which is an ordinary finite-dimensional representation. We want to define a character associated to a graded representation, but if a character is to have any hope of uniquely describing a representation it must contain information about the character on every finite-dimensional piece simultaneously. The natural definition here is the graded trace
$\displaystyle \chi_V(g) = \sum_{n \ge 0} \chi_{V_n}(g) t^n$.
In particular, the graded trace of the identity is the graded dimension or Hilbert series of $V$.
Classically a case of particular interest is when $V_n = \text{Sym}^n(W^{*})$ for some fixed representation $W$, since $V = \text{Sym}(W^{*})$ is the symmetric algebra (in particular, commutative ring) of polynomial functions on $W$ invariant under $G$. In the nicest cases (for example when $G$ is finite), $V$ is finitely generated, hence Noetherian, and $\text{Spec } V$ is a variety which describes the quotient $W/G$.
In a previous post we discussed instead the case where $V_n = (W^{*})^{\otimes n}$ for some fixed representation $W$, hence $V$ is the tensor algebra of functions on $W$. I thought it might be interesting to discuss some generalities about these graded representations, so that’s what we’ll be doing today.
## The Jacobi-Trudi identities
Today I’d like to introduce a totally explicit combinatorial definition of the Schur functions. Let $\lambda \vdash n$ be a partition. A semistandard Young tableau $T$ of shape $\lambda$ is a filling of the Young diagram of $\lambda$ with positive integers that are weakly increasing along rows and strictly increasing along columns. The weight of a tableau $T$ is defined as $\mathbf{x}^T = x_1^{T_1} x_2^{T_2} ...$ where $T_i$ is the total number of times $i$ appears in the tableau.
Definition 4: $\displaystyle s_{\lambda}(x_1, x_2, ...) = \sum_T \mathbf{x}^T$
where the sum is taken over all semistandard Young tableaux of shape $\lambda$.
As before we can readily verify that $s_{(k)} = h_k, s_{(1^k)} = e_k$. This definition will allow us to deduce the Jacobi-Trudi identities for the Schur functions, which describe among other things the action of the fundamental involution $\omega$. Since I’m trying to emphasize how many different ways there are to define the Schur functions, I’ll call these definitions instead of propositions.
Definition 5: $\displaystyle s_{\lambda}= \det(h_{\lambda_i+j-i})_{1 \le i, j \le n}$.
Definition 6: $\displaystyle s_{\lambda'} = \det(e_{\lambda_i+j-i})_{1 \le i, j \le n}$.
## The many faces of Schur functions
The last time we talked about symmetric functions, I asked whether the vector space $\mathcal{R}$ could be turned into an algebra, i.e. equipped with a nice product. It turns out that the induced representation allows us to construct such a product as follows:
Given representations $\rho_1, \rho_2$ of $S_n, S_m$, their tensor product $\rho_1 \otimes \rho_2$ is a representation of the direct product $S_n \times S_m$ in a natural way. Now, $S_n \times S_m$ injects naturally into $S_{n+m}$, which gives a new representation
$\rho = \text{Ind}_{S_n \times S_m}^{S_{n+m}} \rho_1 \otimes \rho_2$.
The character of this representation is called the induction product $\rho_1 * \rho_2$ of the characters of $\rho_1, \rho_2$, and with this product $\mathcal{R}$ becomes a graded commutative algebra. (Commutativity and associativity are fairly straightforward to verify.) It now remains to answer the first question: does there exist an algebra homomorphism $\phi : \Lambda \to \mathcal{R}$? And can we describe the inner product on $\Lambda$ coming from the inner product on $\mathcal{R}$?
To answer this question we’ll introduce perhaps the most important class of symmetric functions, the Schur functions $s_{\lambda}$.
N.B. I’ll be skipping even more proofs than usual today, partly because they require the development of a lot of machinery I haven’t described and partly because I don’t understand them all that well. Again, good references are Sagan or EC2.
## Set-multiset duality and supervector spaces
Recall that the elementary symmetric functions $e_{\lambda}$ generate the ring of symmetric functions $\Lambda$ as a module over any commutative ring $R$. A corollary of this result, although I didn’t state it explicitly, is that the elementary symmetric functions $e_1, e_2, ...$ are algebraically independent, hence any ring homomorphism from the symmetric functions is determined freely by the images of $e_1, e_2, ...$.
A particularly interesting choice of endomorphism $\omega : \Lambda \to \Lambda$ occurs when we set $\omega(e_n) = h_n$. This endomorphism sends the generating function $E(t)$ for the elementary symmetric polynomials to the generating function $H(t) = \frac{1}{E(-t)}$, and this is an involution – in other words, it follows that $\omega(h_n) = e_n$ and $\omega$ itself must also be an involution on the ring of symmetric functions. Thus the elementary symmetric functions and complete homogeneous symmetric functions are dual in a very strong sense. This is closely related to the identity
$\displaystyle \left( {n \choose d} \right) = (-1)^d {-n \choose d}$
and today I’d like to try to explain one interpretation of what’s going on that I learned from Todd Trimble, which is that “the exterior algebra is the symmetric algebra of a purely odd supervector space.”
## Newton’s sums, necklace congruences, and zeta functions II
In a previous post I gave essentially the following definition: given a discrete dynamical system, i.e. a space $X$ and a function $f : X \to X$, and under the assumption that $f^n$ has a finite number of fixed points for all $n$, we define the dynamical zeta function to be the formal power series
$\displaystyle \zeta_X(t) = \exp \sum_{n \ge 1} (\text{Fix } f^n) \frac{t^n}{n}$.
What I didn’t do was motivate this definition, mostly because I hadn’t really worked out the motivation myself. Now that we have an important special case worked out, we can discuss the general case, which will give a purely combinatorial proof of the second half of the Newton-Girard identities.
## Newton’s sums, necklace congruences, and zeta functions
The goal of this post is to give a purely combinatorial proof of Newton’s sums which would have interrupted the flow of the previous post. Recall that, in the notation of the previous post, Newton’s sums (also known as the first Newton-Girard identity) state that
$\displaystyle p_k - e_1 p_{k-1} \pm ... = (-1)^{k+1} ke_k$.
One way to motivate a combinatorial proof is to recast the generating function interpretation appropriately. Given a polynomial $C(t)$ with non-negative integer coefficients and $C(0) = 0$, let $r_1, ... r_n$ be the reciprocals of the roots of $C(t) - 1 = 0$. Then
$\displaystyle \frac{t C'(t)}{1 - C(t)} = \sum_{k \ge 1} p_k(r_1, ... r_n) t^k$.
The left hand side of this identity suggests a particular interpretation in terms of the combinatorial species described by $C(t)$. Today we’ll describe this species when $C(t)$ is a polynomial with non-negative integer coefficients and then describe it in the general case, which will handle the extension to the symmetric function case as well.
The method of proof used here is closely related to a post I made previously about the properties of the Frobenius map, and at the end of the post I’ll try to discuss what I think might be going on. | {"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": 94, "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": 0.9734053611755371, "perplexity": 112.15927155470682}, "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/1575540502120.37/warc/CC-MAIN-20191207210620-20191207234620-00513.warc.gz"} |
https://noncommutativeanalysis.wordpress.com/category/dynamical-systems/ | ## Category: Dynamical systems
### “Guided” and “quantised” dynamical systems
Evegenios Kakariadis and I have recently posted our paper “On operator algebras associated with monomial ideals in noncommuting variables” on the arxiv. The subject of the paper is several operator algebras (at the outset, there are seven algebras, but later we prove that some are isomorphic to others) that one can associate with each monomial ideal, in such a way that these algebras encode various aspects of the relations defining the ideal.
I refer you to the abstract and intro of that paper for more information about we do there. In this post I would like to discuss at some length an issue that came up writing the paper, and the paper itself was not an appropriate place to have this discussion.
### Where have all the functional equations gone (part II)
I’ll start off exactly where I stopped in the previous post: I will tell you my solution to the problem my PDEs lecturer (and later master’s thesis advisor) Paneah gave us:
Problem: Find all continuously differentiable solutions to the following functional equation:
(FE) $f(t) = f\left(\frac{t+1}{2} \right) + f \left(\frac{t-1}{2} \right) \,\, , \,\, t \in [-1,1] .$
Before writing a solution, let me say that I think it is a fun exercise for undergraduate students, and only calculus is required for solving it, so if you want to try it now is your chance. | {"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": 1, "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": 0.8577186465263367, "perplexity": 536.2405026340989}, "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-2017-30/segments/1500549423903.35/warc/CC-MAIN-20170722062617-20170722082617-00439.warc.gz"} |
https://www.ias.ac.in/listing/bibliography/pram/CHAOUCHE_YASSINE | • CHAOUCHE YASSINE
Articles written in Pramana – Journal of Physics
• Structural, elastic and dynamical properties of ${\rm YP}_{1-x}{\rm As}_{x}$ alloys from first principles calculations
The structural, elastic and lattice vibration properties of the ternary alloys ${\rm YP}_{1-x}{\rm As}_{x}$ at various As concentrations ($x$) from 0 to 1, $x=0, 0.25 ,0.5, 0.75$ and 1, are presented. The calculations were performed using the density functional perturbation theory (DFPT) within the generalised gradient approximation (GGA) and employing virtual crystal approximation (VCA). We studied the effect of arsenic composition on structural parameters, the phase transition pressure, the elastic constants, the optical and acoustic phonon frequencies at high symmetry points $\Gamma$, $X$ and $L$, the static and electronic dielectric constants, and the Born effective charge. It is established that all these properties follow a quadratic law in the concentration ($x$). There is a good agreement between our results and the available data for binary compounds YP and YAs. Our results are predictions of ${\rm YP}_{1-x}{\rm As}_{x}$.
• Theoretical prediction of lanthanum composition effects on structural, electronic and thermal properties of La$_x$Sc$_{1−x}$N alloys
In this study, we have explored the structural, electronic and thermal properties of La$_x$Sc$_{1−x}$N ternary alloys in rock-salt structure using the full-potential linearised augmented plane wave (FP-LAPW) method based on the density functional theory (DFT). To calculate the exchange-correlation energy and potential, we have used the Wu–Cohen generalised gradient approximation and the modified Becke–Johnson. We investigated the effect of composition on lattice parameters, bulk modulus and band gap. The variation of the calculated lattice constant with lanthanum composition is practically linear and shows a small deviation of the obtained results from Vegard’s law. Moreover, the effect of thermal macroscopic properties was also investigated employing the quasiharmonic Debye model, which takes into account the lattice vibrations. We have found a good accord between our results, the experimental data and previous theoretical results available in the literature for the binary compounds which can be a support for the ternary alloys in the future.
• # Pramana – Journal of Physics
Volume 96, 2022
All articles
Continuous Article Publishing mode
• # Editorial Note on Continuous Article Publication
Posted on July 25, 2019 | {"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": 0.7299131751060486, "perplexity": 1368.8486115141384}, "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-2022-27/segments/1656103917192.48/warc/CC-MAIN-20220701004112-20220701034112-00494.warc.gz"} |
http://wwws.esrf.eu/home/news/spotlight/content-news/spotlight/spotlight223.html | # Strong X-ray magneto-chiral dichroism in paramagnetic molecular helices
30-03-2015
Chiral systems, objects that are not superimposable on their mirror images, show differential absorption of left and right circularly polarised light. When chiral systems are also magnetic, they can adsorb unpolarised light in a different way depending on the direction of the chirality, magnetisation, and propagation of light vectors. This effect, known as magneto-chiral dichroism, was observed for the first time only in 1997 with visible [1] light and even more recently with X-rays [2]. The magnetochiral effect has been speculated to be a possible origin of the homochirality of life on earth, as an alternative to the parity-violating electroweak nuclear interactions [3]. It is also of interest for photonic applications but very few examples of magneto-chiral dichroism are available in the literature, most of them reporting a very weak effect. Recently, very strong magneto-chiral dichroism in paramagnetic chiral molecular systems in the hard X-ray range has been detected at ESRF’s beamline ID12.
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The interplay between chirality and magnetism has previously attracted the interest of many eminent scientists including Pasteur [4], and it continues to be at the centre of intense research activity. Magnetism and chirality are indeed connected in the interaction of a chiral system with light through magneto-chiral dichroism, which is observable only in systems where both inversion and time-reversal symmetries are simultaneously broken. These symmetry conditions are satisfied in magneto-electric media and multiferroics and also in chiral media placed in a magnetic field. The striking features of magneto-chiral dichroism can be derived from symmetry considerations. It is independent of light polarisation but its sign depends on both the relative orientation of the light propagation direction, the applied magnetic field and the sample chirality. Magneto-chiral dichroism is in general very weak, commonly assumed proportional to the product of two other weak phenomena: natural and magnetic circular dichroism. Only a few examples have been reported in the literature and no systematic experimental studies on the origin of the phenomenon are available.
Two molecular helices crystallising in enantiopure trigonal crystals and comprising cobalt(II) or manganese(II) ions bridged by stable organic radicals (see Figure 1a) have been investigated at the K-edge of the transition metals using the unique capabilities of beamline ID12. All three dichroic spectra (X-ray magnetic circular dichroism (XMCD), X-ray natural circular dichroism (XNCD) and X-ray magnetochiral dichroism (XMχD)) have been measured on pairs of opposite enantiomers, using single crystals with a volume of the order of a mm3. The use of single crystals, or more generally of oriented samples, is mandatory given that the magneto-chiral dichroism in the X-ray range is dominated by the quadrupolar term of the expansion of the light-matter interaction, thus vanishing in isotropic media.
Figure 1. a) Simplified structure of the [M(hfac)2(NITPhOMe)]∞ molecular helices (M=Co and Mn, hfac=hexafluoroacetylacetonate) winding clockwise or anticlockwise along the c crystallographic axis depending on the crystallisation in the P31 or P32 space groups. The bridging radical unit is highlighted by the red circle. b) The experimental X-ray absorption (XANES) at the Co K-edge recorded on a single crystal at 5 K and under a magnetic field of 3 Tesla is reported together with the three measured dichroic contributions: natural circular (XNCD), magnetic circular (XMCD) and magneto-chiral (XMχD) dichroism.
The results for the cobalt derivatives are reported in Figure 1b. The availability of both enantiomers has allowed us to check the change of sign for XNCD and XMχD signals as well as the change in sign upon the reversal of the magnetic field for XMCD and XMχD. In addition, the magneto-chiral dichroism is comparable to the natural dichroism and larger than the magnetic dichroism, clearly indicating that the common assumption that the magneto-chiral dichroism is the product of two weak phenomena is not valid, at least in the hard X-ray regime.
Figure 1a clearly shows that the spectral shapes of the three dichroic contributions are very different, the magneto-chiral dichroism emerging as a narrow peak coincident with transitions from 1s to 3d orbitals of the cobalt atom induced by electric quadrupolar interactions. Interestingly, the isomorphous compound containing manganese(II), an isotropic magnetic ion given its d5 configuration, exhibits similar XNCD and XMCD signals but a vanishingly small magneto-chiral dichroism. The orbital magnetism of the cobalt ion is also responsible for the non collinear spin structure of this molecular helix, which seems therefore correlated to the observed strong magneto-chiral dichroism.
It is interesting to note that, while XMCD measured at the K-edge of transition metal ions provides information on the orbital magnetic moment of the ion, XMχD gives access to a more elusive quantity: the anapole orbital current or orbital toroidal moment. The two quantities are schematised in Figure 2. They are both time reversal odd, i.e. they change sign reversing the arrows of the current, but only the latter is non-symmetric with respect to the inversion symmetry, i.e. is parity odd.
Figure 2. Representation of the orbital dipolar currents (in blue) and orbital anapole currents (in red) of the Co atom detected at the K-edge through the measurement of the magnetic circular and magneto-chiral dichroism, respectively.
Orbital toroidal currents seem to be involved in different phenomena ranging from multiferroicity to superconductivity, and their accurate determination through hard X-ray spectroscopy has been demonstrated here.
Principal publication and authors
Strong magneto-chiral dichroism in a paramagnetic molecular helix observed by hard X-rays, R. Sessoli (a), M.–E. Boulon (a), A. Caneschi (a), M. Mannini (a), L. Poggini (a), F. Wilhelm (b) & A. Rogalev (b), Nature Physics 11, 69 (2015).
(a) Department of Chemistry ‘Ugo Schiff’ and INSTM Research Unit, University of Florence (Italy)
(b) ESRF
References
[1] G.L.J.A. Rikken and E. Raupach, Nature 390, 493 (1997).
[2] J. Goulon et al., Phys. Rev. Lett. 88, 237401 (2002).
[3] L.D. Barron, in Physical Origin of Homochirality in Life, ed. by D.B. Cline AIP, Woodbury, NY, 1996.
[4] L. Pasteur, Rev. Sci. 7, 2 (1884).
Top image: The orbital dipolar currents (in blue) and orbital anapole currents (in red) of the Co atom. | {"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": 0.8373410105705261, "perplexity": 2609.9650747822875}, "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/1603107887810.47/warc/CC-MAIN-20201025041701-20201025071701-00418.warc.gz"} |
http://mathhelpforum.com/calculus/28704-please-help-involves-area-integral-print.html | • Feb 20th 2008, 09:33 AM
waite3
Find the area of the region enclosed between y=4sin(x) and y=3cos(x) from x=0 to x=0.9pi .
• Feb 20th 2008, 09:40 AM
Jhevon
Quote:
Originally Posted by waite3
Find the area of the region enclosed between y=4sin(x) and y=3cos(x) from x=0 to x=0.9pi .
the area will be given by $\int_0^{0.9 \pi} (\mbox{Top function } - \mbox{ Bottom function})~dx$
so which is which?
note that the functions switch roles at some point in the interval
• Feb 20th 2008, 09:50 AM
waite3
the sin function is the top and we get 6.877, yet the online program for submission being used is saying that that answer is incorrect, whereabouts would my error be lying? thanks for the help
• Feb 20th 2008, 11:45 AM
xifentoozlerix
why dont you graph the two functions? you will see why your answer is wrong.
hint: $cos(0)=1$ while $sin(0)=0$ | {"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": 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": 0.9596143960952759, "perplexity": 2103.787900976957}, "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-2016-40/segments/1474738661953.95/warc/CC-MAIN-20160924173741-00015-ip-10-143-35-109.ec2.internal.warc.gz"} |
https://math.stackexchange.com/questions/2973672/proving-that-a-representation-is-irreducible | # Proving that a representation is irreducible
Let $$V_n = \mathbb{C}^n$$ the representations of $$SU(n)$$ given by matrix multiplication $$SU(n) \times V_n \rightarrow V_n, (A, v) \mapsto A \cdot v .\,$$ Show that $$V_n$$ is irreducible.
I tried to prove this by induction using the fact that the representation is completely reducible, because $$SU(n)$$ is a compact Lie group, but I'm not sure is the right way to do it.
Let $$v\in V_n\setminus\{0\}$$. For each $$w\in V_n$$ such that $$\|w\|=\|v\|$$, there is a $$M\in SU(n)$$ such that $$M.v=w$$. Therefore, if $$U\subset V_n$$ is a vector subspace such that
• $$v\in U$$;
• $$SU(n).U\subset U$$,
then $$U\supset\{w\in V_n\,|\,\|w\|=\|v\|\}$$. But then $$U=V_n$$.
• Sorry, I'm not sure anymore to have all understood... How can you affirm the existence of a matrix $M \in SU(n)$ such that $M \cdot v = w$? It follows maybe from the fact that for all vectors $w \in V_n$ such that $||w|| = ||v||$ we have that $||A \cdot v|| = ||w||$ for all $A \in SU(n)$? – userr777 Nov 3 '18 at 15:39
• No. Let $v_1=\frac v{\|v\|}$, and consider vectors $v_2,\ldots,v_n$ such that $(v_1,v_2,\ldots,v_n)$ is an orthonormal basis. Then the matrix $P$ whose columns are the $v_i$'s belongs to $SU(n)$ and $P.e_1=v_1$. Now, you construct a matrix $Q$ from $w$ by the same process. Then $Q.P^{-1}\in SU(n)$ and $Q(P^{-1}.v_1)=Q.e_1=w_1$. Therefore, $Q(P^{-1}.v)=w$. – José Carlos Santos Nov 3 '18 at 16:08 | {"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": 15, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9957967400550842, "perplexity": 80.52656479800989}, "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/1566027323067.50/warc/CC-MAIN-20190825042326-20190825064326-00113.warc.gz"} |
http://proceedings.mlr.press/v32/tu14.html | # Making Fisher Discriminant Analysis Scalable
Bojun Tu, Zhihua Zhang, Shusen Wang, Hui Qian ;
Proceedings of the 31st International Conference on Machine Learning, PMLR 32(2):964-972, 2014.
#### Abstract
The Fisher linear discriminant analysis (LDA) is a classical method for classification and dimension reduction jointly. A major limitation of the conventional LDA is a so-called singularity issue. Many LDA variants, especially two-stage methods such as PCA+LDA and LDA/QR, were proposed to solve this issue. In the two-stage methods, an intermediate stage for dimension reduction is developed before the actual LDA method works. These two-stage methods are scalable because they are an approximate alternative of the LDA method. However, there is no theoretical analysis on how well they approximate the conventional LDA problem. In this paper we present theoretical analysis on the approximation error of a two-stage algorithm. Accordingly, we develop a new two-stage algorithm. Furthermore, we resort to a random projection approach, making our algorithm scalable. We also provide an implemention on distributed system to handle large scale problems. Our algorithm takes LDA/QR as its special case, and outperforms PCA+LDA while having a similar scalability. We also generalize our algorithm to kernel discriminant analysis, a nonlinear version of the classical LDA. Extensive experiments show that our algorithms outperform PCA+LDA and have a similar scalability with it. | {"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": 0.8670094609260559, "perplexity": 1225.796420398306}, "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/1581875143695.67/warc/CC-MAIN-20200218120100-20200218150100-00468.warc.gz"} |
https://worldwidescience.org/topicpages/a/acoustic+multivariate+condition.html | #### Sample records for acoustic multivariate condition
1. Acoustic multivariate condition monitoring - AMCM
Rosenhave, P.E. [Vestfold College, Maritime Dept., Toensberg (Norway)
1997-12-31
In Norway, Vestfold College, Maritime Department presents new opportunities for non-invasive, on- or off-line acoustic monitoring of rotating machinery such as off-shore pumps and diesel engines. New developments within acoustic sensor technology coupled with chemometric data analysis of complex signals now allow condition monitoring of hitherto unavailable flexibility and diagnostic specificity. Chemometrics paired with existing knowledge yields a new and powerful tool for condition monitoring. By the use of multivariate techniques and acoustics it is possible to quantify wear and tear as well as predict the performance of working components in complex machinery. This presentation describes the AMCM method and one result of a feasibility study conducted onboard the LPG/C Norgas Mariner owned by Norwegian Gas Carriers as (NGC), Oslo. (orig.) 6 refs.
2. On the Conditional Distribution of the Multivariate $t$ Distribution
Ding, Peng
2016-01-01
As alternatives to the normal distributions, $t$ distributions are widely applied in robust analysis for data with outliers or heavy tails. The properties of the multivariate $t$ distribution are well documented in Kotz and Nadarajah's book, which, however, states a wrong conclusion about the conditional distribution of the multivariate $t$ distribution. Previous literature has recognized that the conditional distribution of the multivariate $t$ distribution also follows the multivariate $t$ ...
3. Absorption boundary conditions for geomertical acoustics
Jeong, Cheol-Ho
2012-01-01
Defining accurate acoustical boundary conditions is of crucial importance for room acoustic simulations. In predicting sound fields using phased geometrical acoustics methods, the absorption coefficients or surface impedances of the boundary surfaces can be used, but no guideline has been developed...... solutions. Two rectangular rooms with uniform and non-uniform absorption distributions are tested. It is concluded that the impedance and random incidence absorption boundary conditions produce reasonable results with some exceptions at low frequencies for acoustically soft materials....
4. Multivariate saddlepoint approximations in tail probability and conditional inference
Kolassa, John; 10.3150/09-BEJ237
2010-01-01
We extend known saddlepoint tail probability approximations to multivariate cases, including multivariate conditional cases. Our approximation applies to both continuous and lattice variables, and requires the existence of a cumulant generating function. The method is applied to some examples, including a real data set from a case-control study of endometrial cancer. The method contains less terms and is easier to implement than existing methods, while showing an accuracy comparable to those methods.
5. Causal Information Approach to Partial Conditioning in Multivariate Data Sets
D. Marinazzo
2012-01-01
Full Text Available When evaluating causal influence from one time series to another in a multivariate data set it is necessary to take into account the conditioning effect of the other variables. In the presence of many variables and possibly of a reduced number of samples, full conditioning can lead to computational and numerical problems. In this paper, we address the problem of partial conditioning to a limited subset of variables, in the framework of information theory. The proposed approach is tested on simulated data sets and on an example of intracranial EEG recording from an epileptic subject. We show that, in many instances, conditioning on a small number of variables, chosen as the most informative ones for the driver node, leads to results very close to those obtained with a fully multivariate analysis and even better in the presence of a small number of samples. This is particularly relevant when the pattern of causalities is sparse.
6. Abstract wave equations with acoustic boundary conditions
Mugnolo, Delio
2010-01-01
We define an abstract setting to treat wave equations equipped with time-dependent acoustic boundary conditions on bounded domains of ${\\bf R}^n$. We prove a well-posedness result and develop a spectral theory which also allows to prove a conjecture proposed in (Gal-Goldstein-Goldstein, J. Evol. Equations 3 (2004), 623-636). Concrete problems are also discussed.
7. Condition Monitoring and Management from Acoustic Emissions
Pontoppidan, Niels Henrik Bohl
2005-01-01
In the following, I will use technical terms without explanation as it gives the freedom to describe the project in a shorter form for those who already know. The thesis is about condition monitoring of large diesel engines from acoustic emission signals. The experiments have been focused...... alignment framework it is shown that non-stationary condition monitoring can be achieved....... on a specific and severe fault called scuffing. The fault is generally assumed to arise from increased interaction between the piston and liner. For generating experimental data destructive tests with no lubrication, oil has been carried out. Focus has been on modeling the normal condition and detecting...
8. An improved multivariate analytical method to assess the accuracy of acoustic sediment classification maps.
Biondo, M.; Bartholomä, A.
2014-12-01
High resolution hydro acoustic methods have been successfully employed for the detailed classification of sedimentary habitats. The fine-scale mapping of very heterogeneous, patchy sedimentary facies, and the compound effect of multiple non-linear physical processes on the acoustic signal, cause the classification of backscatter images to be subject to a great level of uncertainty. Standard procedures for assessing the accuracy of acoustic classification maps are not yet established. This study applies different statistical techniques to automated classified acoustic images with the aim of i) quantifying the ability of backscatter to resolve grain size distributions ii) understanding complex patterns influenced by factors other than grain size variations iii) designing innovative repeatable statistical procedures to spatially assess classification uncertainties. A high-frequency (450 kHz) sidescan sonar survey, carried out in the year 2012 in the shallow upper-mesotidal inlet the Jade Bay (German North Sea), allowed to map 100 km2 of surficial sediment with a resolution and coverage never acquired before in the area. The backscatter mosaic was ground-truthed using a large dataset of sediment grab sample information (2009-2011). Multivariate procedures were employed for modelling the relationship between acoustic descriptors and granulometric variables in order to evaluate the correctness of acoustic classes allocation and sediment group separation. Complex patterns in the acoustic signal appeared to be controlled by the combined effect of surface roughness, sorting and mean grain size variations. The area is dominated by silt and fine sand in very mixed compositions; in this fine grained matrix, percentages of gravel resulted to be the prevailing factor affecting backscatter variability. In the absence of coarse material, sorting mostly affected the ability to detect gradual but significant changes in seabed types. Misclassification due to temporal discrepancies
9. Introducing passive acoustic filter in acoustic based condition monitoring: Motor bike piston-bore fault identification
Jena, D. P.; Panigrahi, S. N.
2016-03-01
Requirement of designing a sophisticated digital band-pass filter in acoustic based condition monitoring has been eliminated by introducing a passive acoustic filter in the present work. So far, no one has attempted to explore the possibility of implementing passive acoustic filters in acoustic based condition monitoring as a pre-conditioner. In order to enhance the acoustic based condition monitoring, a passive acoustic band-pass filter has been designed and deployed. Towards achieving an efficient band-pass acoustic filter, a generalized design methodology has been proposed to design and optimize the desired acoustic filter using multiple filter components in series. An appropriate objective function has been identified for genetic algorithm (GA) based optimization technique with multiple design constraints. In addition, the sturdiness of the proposed method has been demonstrated in designing a band-pass filter by using an n-branch Quincke tube, a high pass filter and multiple Helmholtz resonators. The performance of the designed acoustic band-pass filter has been shown by investigating the piston-bore defect of a motor-bike using engine noise signature. On the introducing a passive acoustic filter in acoustic based condition monitoring reveals the enhancement in machine learning based fault identification practice significantly. This is also a first attempt of its own kind.
10. Room Acoustic Conditions of Performers in AN Old Opera House
IANNACE, GINO; IANNIELLO, CARMINE; MAFFEI, LUIGI; ROMANO, ROSARIO
2000-04-01
Proposed objective criteria related to the acoustic conditions for instrumentalists and singers have not received a sufficiently wide consent yet. In spite of this situation, it is the opinion of the authors that the measurement of existing criteria is useful for analysis and comparison. This paper reports the results of various acoustic measurements carried out in the Teatro di San Carlo, Naples-Italy, with the aim of obtaining objective information about its acoustics for performers. A first set of measurements was carried out when the theater was fitted for a symphonic concert and a second one when it was fitted for an opera performance.
11. Atmospheric conditions, lunar phases, and childbirth: a multivariate analysis
Ochiai, Angela Megumi; Gonçalves, Fabio Luiz Teixeira; Ambrizzi, Tercio; Florentino, Lucia Cristina; Wei, Chang Yi; Soares, Alda Valeria Neves; De Araujo, Natalucia Matos; Gualda, Dulce Maria Rosa
2012-07-01
Our objective was to assess extrinsic influences upon childbirth. In a cohort of 1,826 days containing 17,417 childbirths among them 13,252 spontaneous labor admissions, we studied the influence of environment upon the high incidence of labor (defined by 75th percentile or higher), analyzed by logistic regression. The predictors of high labor admission included increases in outdoor temperature (odds ratio: 1.742, P = 0.045, 95%CI: 1.011 to 3.001), and decreases in atmospheric pressure (odds ratio: 1.269, P = 0.029, 95%CI: 1.055 to 1.483). In contrast, increases in tidal range were associated with a lower probability of high admission (odds ratio: 0.762, P = 0.030, 95%CI: 0.515 to 0.999). Lunar phase was not a predictor of high labor admission ( P = 0.339). Using multivariate analysis, increases in temperature and decreases in atmospheric pressure predicted high labor admission, and increases of tidal range, as a measurement of the lunar gravitational force, predicted a lower probability of high admission.
12. Retention of acoustic conditioning in St Peter's fish Sarotherodon galilaeus.
Zion, B; Barki, A; Grinshpon, J; Rosenfeld, L; Karplus, I
2011-03-01
Groups of St Peter's fish Sarotherodon galilaeus were trained during 28 days of classical conditioning to respond to an acoustic signal by approaching a feeder. Their ability to retain the acoustically conditioned behaviour was tested after eight different intervals ranging from 12 to 188 days from termination of training. Retention tests comprised 7 consecutive days of retraining and the fish response was compared with that of naive fish. Fish response drastically diminished with time. After 55 days, there was no apparent expression of memory on the first test day but fish response was restored on subsequent retraining days, indicating the existence of latent memory. Six months from the end of training, there was no indication of behavioural retention and the response completely vanished. The study was conducted in the context of sea ranching, with classical conditioning used to gain control over fish location. In light of the present results, it is suggested that periodic reinforcement of the acoustically conditioned behaviour should be used.
13. An Asymmetric Block Dynamic Conditional Correlation Multivariate GARCH Model
Vargas, Gregorio A.
2006-01-01
The Block DCC model for determining dynamic correlations within and between groups of financial asset returns is extended to account for asymmetric effects. Simulation results show that the Asymmetric Block DCC model is competitive in in-sample forecasting and performs better than alternative DCC models in out-of-sample forecasting of conditional correlation in the presence of asymmetric effect between blocks of asset returns. Empirical results demonstrate that the model is able to capture ...
14. Equal autophonic level curves under different room acoustics conditions
Pelegrin Garcia, David; Mendizábal, Oier Fuentes; Brunskog, Jonas;
2011-01-01
The indirect auditory feedback from one’s own voice arises from sound reflections at the room boundaries or from sound reinforcement systems. The relative variations of indirect auditory feedback are quantified through room acoustic parameters such as the room gain and the voice support, rather...... than the reverberation time. Fourteen subjects matched the loudness level of their own voice (the autophonic level) to that of a constant and external reference sound, under different synthesized room acoustics conditions. The matching voice levels are used to build a set of equal autophonic level...... curves. These curves give an indication of the amount of variation in voice level induced by the acoustic environment as a consequence of the sidetone compensation or Lombard effect. In the range of typical rooms for speech, the variations in overall voice level that result in a constant autophonic level...
15. Asymptotics for the Conditional-Sum-of-Squares Estimator in Multivariate Fractional Time-Series Models
Ørregård Nielsen, Morten
2015-01-01
This article proves consistency and asymptotic normality for the conditional-sum-of-squares estimator, which is equivalent to the conditional maximum likelihood estimator, in multivariate fractional time-series models. The model is parametric and quite general and, in particular, encompasses...
16. Asymptotics for the conditional-sum-of-squares estimator in multivariate fractional time series models
Ørregård Nielsen, Morten
This paper proves consistency and asymptotic normality for the conditional-sum-of-squares estimator, which is equivalent to the conditional maximum likelihood estimator, in multivariate fractional time series models. The model is parametric and quite general, and, in particular, encompasses...
17. DESIGN OF ENVELOPE STRUCTURES OF BUILDINGS WITH ACCOUNT FOR AND SUBJECT TO THE CONDITIONS OF ACOUSTIC PROTECTION
Giyasov Botir Iminzhonovich
2012-12-01
Full Text Available The totality of all environmental influences, including domestic and industrial noise, must be taken into account in the design of building structures. Building envelopes that have appropriate acoustic protection properties are to be used in the practice of the acoustic protection (soundproofing, etc.. According to the principles of structural design, design of soundproof buildings can be broken down into the two groups: design with account for the security conditions (eg., windows, doors, walls, floors, and design of noise-proof structures (eg., partitions, suspended ceilings. Multi-optional design of building structures or buildings that meet the terms of acoustic protection requires a modern approach to the process of their development. Any progress in this area is associated with computer-aided design supported by multiple analysis options. Automation allows adjustments in order to comply with the variety of the input data or objective functions to provide for optimal cycling options. In this regard, the authors describe the algorithms and principles of design of building envelopes on the condition of and subject to the acoustic protection. The proposed solution represents a software package capable of performing a multivariate analysis of options of acoustic protection at each stage of building design. Practical application of the software package used to solve practical problems in the design of building envelopes has demonstrated its higher efficiency that the one of traditional design methods.
18. Optimizing acoustical conditions for speech intelligibility in classrooms
Yang, Wonyoung
High speech intelligibility is imperative in classrooms where verbal communication is critical. However, the optimal acoustical conditions to achieve a high degree of speech intelligibility have previously been investigated with inconsistent results, and practical room-acoustical solutions to optimize the acoustical conditions for speech intelligibility have not been developed. This experimental study validated auralization for speech-intelligibility testing, investigated the optimal reverberation for speech intelligibility for both normal and hearing-impaired listeners using more realistic room-acoustical models, and proposed an optimal sound-control design for speech intelligibility based on the findings. The auralization technique was used to perform subjective speech-intelligibility tests. The validation study, comparing auralization results with those of real classroom speech-intelligibility tests, found that if the room to be auralized is not very absorptive or noisy, speech-intelligibility tests using auralization are valid. The speech-intelligibility tests were done in two different auralized sound fields---approximately diffuse and non-diffuse---using the Modified Rhyme Test and both normal and hearing-impaired listeners. A hybrid room-acoustical prediction program was used throughout the work, and it and a 1/8 scale-model classroom were used to evaluate the effects of ceiling barriers and reflectors. For both subject groups, in approximately diffuse sound fields, when the speech source was closer to the listener than the noise source, the optimal reverberation time was zero. When the noise source was closer to the listener than the speech source, the optimal reverberation time was 0.4 s (with another peak at 0.0 s) with relative output power levels of the speech and noise sources SNS = 5 dB, and 0.8 s with SNS = 0 dB. In non-diffuse sound fields, when the noise source was between the speaker and the listener, the optimal reverberation time was 0.6 s with
19. Classification of heart valve condition using acoustic measurements
Clark, G. [Lawrence Livermore National Lab., CA (United States)
1994-11-15
Prosthetic heart valves and the many great strides in valve design have been responsible for extending the life spans of many people with serious heart conditions. Even though the prosthetic valves are extremely reliable, they are eventually susceptible to long-term fatigue and structural failure effects expected from mechanical devices operating over long periods of time. The purpose of our work is to classify the condition of in vivo Bjork-Shiley Convexo-Concave (BSCC) heart valves by processing acoustic measurements of heart valve sounds. The structural failures of interest for Bscc valves is called single leg separation (SLS). SLS can occur if the outlet strut cracks and separates from the main structure of the valve. We measure acoustic opening and closing sounds (waveforms) using high sensitivity contact microphones on the patients thorax. For our analysis, we focus our processing and classification efforts on the opening sounds because they yield direct information about outlet strut condition with minimal distortion caused by energy radiated from the valve disc.
20. Linking multimetric and multivariate approaches to assess the ecological condition of streams.
Collier, Kevin J
2009-10-01
Few attempts have been made to combine multimetric and multivariate analyses for bioassessment despite recognition that an integrated method could yield powerful tools for bioassessment. An approach is described that integrates eight macroinvertebrate community metrics into a Principal Components Analysis to develop a Multivariate Condition Score (MCS) from a calibration dataset of 511 samples. The MCS is compared to an Index of Biotic Integrity (IBI) derived using the same metrics based on the ratio to the reference site mean. Both approaches were highly correlated although the MCS appeared to offer greater potential for discriminating a wider range of impaired conditions. Both the MCS and IBI displayed low temporal variability within reference sites, and were able to distinguish between reference conditions and low levels of catchment modification and local habitat degradation, although neither discriminated among three levels of low impact. Pseudosamples developed to test the response of the metric aggregation approaches to organic enrichment, urban, mining, pastoral and logging stressor scenarios ranked pressures in the same order, but the MCS provided a lower score for the urban scenario and a higher score for the pastoral scenario. The MCS was calculated for an independent test dataset of urban and reference sites, and yielded similar results to the IBI. Although both methods performed comparably, the MCS approach may have some advantages because it removes the subjectivity of assigning thresholds for scoring biological condition, and it appears to discriminate a wider range of degraded conditions.
1. Surface Acoustic Wave (SAW) Resonators for Monitoring Conditioning Film Formation.
Hohmann, Siegfried; Kögel, Svea; Brunner, Yvonne; Schmieg, Barbara; Ewald, Christina; Kirschhöfer, Frank; Brenner-Weiß, Gerald; Länge, Kerstin
2015-05-21
We propose surface acoustic wave (SAW) resonators as a complementary tool for conditioning film monitoring. Conditioning films are formed by adsorption of inorganic and organic substances on a substrate the moment this substrate comes into contact with a liquid phase. In the case of implant insertion, for instance, initial protein adsorption is required to start wound healing, but it will also trigger immune reactions leading to inflammatory responses. The control of the initial protein adsorption would allow to promote the healing process and to suppress adverse immune reactions. Methods to investigate these adsorption processes are available, but it remains difficult to translate measurement results into actual protein binding events. Biosensor transducers allow user-friendly investigation of protein adsorption on different surfaces. The combination of several transduction principles leads to complementary results, allowing a more comprehensive characterization of the adsorbing layer. We introduce SAW resonators as a novel complementary tool for time-resolved conditioning film monitoring. SAW resonators were coated with polymers. The adsorption of the plasma proteins human serum albumin (HSA) and fibrinogen onto the polymer-coated surfaces were monitored. Frequency results were compared with quartz crystal microbalance (QCM) sensor measurements, which confirmed the suitability of the SAW resonators for this application.
2. Surface Acoustic Wave (SAW Resonators for Monitoring Conditioning Film Formation
Siegfried Hohmann
2015-05-01
Full Text Available We propose surface acoustic wave (SAW resonators as a complementary tool for conditioning film monitoring. Conditioning films are formed by adsorption of inorganic and organic substances on a substrate the moment this substrate comes into contact with a liquid phase. In the case of implant insertion, for instance, initial protein adsorption is required to start wound healing, but it will also trigger immune reactions leading to inflammatory responses. The control of the initial protein adsorption would allow to promote the healing process and to suppress adverse immune reactions. Methods to investigate these adsorption processes are available, but it remains difficult to translate measurement results into actual protein binding events. Biosensor transducers allow user-friendly investigation of protein adsorption on different surfaces. The combination of several transduction principles leads to complementary results, allowing a more comprehensive characterization of the adsorbing layer. We introduce SAW resonators as a novel complementary tool for time-resolved conditioning film monitoring. SAW resonators were coated with polymers. The adsorption of the plasma proteins human serum albumin (HSA and fibrinogen onto the polymer-coated surfaces were monitored. Frequency results were compared with quartz crystal microbalance (QCM sensor measurements, which confirmed the suitability of the SAW resonators for this application.
3. The liquid phase separation of Bi-Ga hypermonotectic alloy under acoustic levitation condition
HONG ZhenYu; L(U) YongJun; XIE WenJun; WEI BingBo
2007-01-01
Containerless treatment of Bi-58.5at%Ga hypermonotectic alloy is successfully performed with acoustic levitation technique. Under acoustic levitation condition, the second phase (Ga) distributes almost homogeneously in solidification sample, opposite to macrosegregation in solidification sample under conventional condition. Stokes motion of the second liquid droplet (Ga) is significantly restrained under acoustic levitation condition. The analyses indicate that the melt vibration in the gravity direction forced by acoustic field can induce steady flow around the second liquid droplet, which influences droplet shape during its moving upward and consequently restrains Stokes motion velocity of the second liquid droplet.
4. Effect of the spatial structure of an acoustic field on Bragg's acoustooptic diffraction under strong acoustic anisotropy conditions
Antonov, S. N.; Vainer, A. V.; Proklov, V. V.; Rezvov, Yu. G.
2010-03-01
Bragg’s acoustooptic diffraction in an acoustically anisotropic medium is considered taking into account the two-dimensional spatial diffraction structure of the acoustic beam. The conditions are determined under which reverse transfer of optical power from the diffracted to the transmitted beam in the regime of 100% efficiency of diffraction is considerably suppressed. It is shown that this effect is due to diffraction bending of wave fronts of the acoustic beam in the acoustooptic diffraction plane. The problem of optimization of the piezoelectric transducer size and the spatial position of the input light beam is solved using the criterion of the minimal required power of the acoustic field. The results of simulation in a wide range of the acoustooptic interaction parameters for a Gaussian light beam are reported. The correctness of the model is confirmed experimentally. Recommendations for designers of acoustooptic devices are formulated.
5. Structural health condition monitoring of rails using acoustic emission techniques
Yilmazer, Pinar
In-service rails can develop several types of structural defects due to fatigue and wear caused by rolling stock passing over them. Most rail defects will develop gradually over time thus permitting inspection engineers to detect them in time before final failure occurs. In the UK, certain types of severe rail defects such as tache ovales, require the fitting of emergency clamps and the imposing of an Emergency Speed Restriction (ESR) until the defects are removed. Acoustic emission (AE) techniques can be applied for the detection and continuous monitoring of defect growth therefore removing the need of imposing strict ESRs. The work reported herewith aims to develop a sound methodology for the application of AE in order to detect and subsequently monitor damage evolution in rails. To validate the potential of the AE technique, tests have been carried out under laboratory conditions on three and four-point bending samples manufactured from 260 grade rail steel. Further tests, simulating the background noise conditions caused by passing rolling stock have been carried out using special experimental setups. The crack growth events have been simulated using a pencil tip break..
6. On the wave equation with semilinear porous acoustic boundary conditions
Graber, Philip Jameson
2012-05-01
The goal of this work is to study a model of the wave equation with semilinear porous acoustic boundary conditions with nonlinear boundary/interior sources and a nonlinear boundary/interior damping. First, applying the nonlinear semigroup theory, we show the existence and uniqueness of local in time solutions. The main difficulty in proving the local existence result is that the Neumann boundary conditions experience loss of regularity due to boundary sources. Using an approximation method involving truncated sources and adapting the ideas in Lasiecka and Tataru (1993) [28], we show that the existence of solutions can still be obtained. Second, we prove that under some restrictions on the source terms, then the local solution can be extended to be global in time. In addition, it has been shown that the decay rates of the solution are given implicitly as solutions to a first order ODE and depends on the behavior of the damping terms. In several situations, the obtained ODE can be easily solved and the decay rates can be given explicitly. Third, we show that under some restrictions on the initial data and if the interior source dominates the interior damping term and if the boundary source dominates the boundary damping, then the solution ceases to exists and blows up in finite time. Moreover, in either the absence of the interior source or the boundary source, then we prove that the solution is unbounded and grows as an exponential function. © 2012 Elsevier Inc.
7. Systems and methods of monitoring acoustic pressure to detect a flame condition in a gas turbine
Ziminsky, Willy Steve (Simpsonville, SC); Krull, Anthony Wayne (Anderson, SC); Healy, Timothy Andrew (Simpsonville, SC), Yilmaz, Ertan (Glenville, NY)
2011-05-17
A method may detect a flashback condition in a fuel nozzle of a combustor. The method may include obtaining a current acoustic pressure signal from the combustor, analyzing the current acoustic pressure signal to determine current operating frequency information for the combustor, and indicating that the flashback condition exists based at least in part on the current operating frequency information.
8. Estimating the impact of environmental conditions on hatching results using multivariable analysis
IA Nääs
2008-12-01
Full Text Available Hatching results are directly related to environmental and biological surroundings. This research study aimed at evaluating the influence of incubation environmental conditions on hatchability and one-day-old chickling quality of five production flocks using multivariable analysis tool. The experiment was carried out in a commercial hatchery located in the state of São Paulo, Brazil. Environmental variables such as dry bulb temperature, relative humidity, carbon dioxide concentration, and number of colony forming units of fungi were recorded inside a broiler multi-stage setter, a hatcher after eggs transference, and a chick-processing room. The homogeneity of parameter distribution among quadrants inside the setter, the hatcher, and the chick room was tested using the non-parametric test of Kruskal-Wallis, and the fit analysis was applied. The multivariate analysis was applied using the Main Component Technique in order to identify possible correlations between environmental and production parameters. Three different groups were identified: the first group is represented by temperature, which was positively correlated both with good hatchability and good chick quality; the second group indicates that poor chick quality was positively correlated with air velocity and relative humidity increase. The third group, represented by carbon dioxide concentration and fungi colonies forming units, presented strong positive association with embryo mortality increase.
9. Distributed acoustic fibre optic sensors for condition monitoring of pipelines
Hussels, Maria-Teresa; Chruscicki, Sebastian; Habib, Abdelkarim; Krebber, Katerina
2016-05-01
Industrial piping systems are particularly relevant to public safety and the continuous availability of infrastructure. However, condition monitoring systems based on many discrete sensors are generally not well-suited for widespread piping systems due to considerable installation effort, while use of distributed fibre-optic sensors would reduce this effort to a minimum. Specifically distributed acoustic sensing (DAS) is employed for detection of third-party threats and leaks in oil and gas pipelines in recent years and can in principle also be applied to industrial plants. Further possible detection routes amenable by DAS that could identify damage prior to emission of medium are subject of a current project at BAM, which aims at qualifying distributed fibre optic methods such as DAS as a means for spatially continuous monitoring of industrial piping systems. Here, first tests on a short pipe are presented, where optical fibres were applied directly to the surface. An artificial signal was used to define suitable parameters of the measurement system and compare different ways of applying the sensor.
10. A multivariate analytical method to characterize sediment attributes from high-frequency acoustic backscatter and ground-truthing data (Jade Bay, German North Sea coast)
Biondo, Manuela; Bartholomä, Alexander
2017-04-01
One of the burning issues on the topic of acoustic seabed classification is the lack of solid, repeatable, statistical procedures that can support the verification of acoustic variability in relation to seabed properties. Acoustic sediment classification schemes often lead to biased and subjective interpretation, as they ultimately aim at an oversimplified categorization of the seabed based on conventionally defined sediment types. However, grain size variability alone cannot be accounted for acoustic diversity, which will be ultimately affected by multiple physical processes, scale of heterogeneity, instrument settings, data quality, image processing and segmentation performances. Understanding and assessing the weight of all of these factors on backscatter is a difficult task, due to the spatially limited and fragmentary knowledge of the seabed from of direct observations (e.g. grab samples, cores, videos). In particular, large-scale mapping requires an enormous availability of ground-truthing data that is often obtained from heterogeneous and multidisciplinary sources, resulting into a further chance of misclassification. Independently from all of these limitations, acoustic segments still contain signals for seabed changes that, if appropriate procedures are established, can be translated into meaningful knowledge. In this study we design a simple, repeatable method, based on multivariate procedures, with the scope to classify a 100 km2, high-frequency (450 kHz) sidescan sonar mosaic acquired in the year 2012 in the shallow upper-mesotidal inlet of the Jade Bay (German North Sea coast). The tool used for the automated classification of the backscatter mosaic is the QTC SWATHVIEWTMsoftware. The ground-truthing database included grab sample data from multiple sources (2009-2011). The method was designed to extrapolate quantitative descriptors for acoustic backscatter and model their spatial changes in relation to grain size distribution and morphology. The
11. The use of acoustic emission for bearing condition monitoring
Lees, A W; Quiney, Z [Swansea University, Singleton Park, Swansea, SA2 8PP (United Kingdom); Ganji, A; Murray, B, E-mail: a.w.lees@swansea.ac.uk, E-mail: z.quiney.294103@swansea.ac.uk, E-mail: ali.ganji@skf.com [SKF Engineering and Research Centre, Kelvinbaan 16, 3439 MT Nieuwegein (Netherlands)
2011-07-19
This paper reports research currently in progress at Swansea University in collaboration with SKF Engineering and Research Centre as part of a continuing investigation into high frequency Acoustic Emission. The primary concerns are experimentally producing subsurface cracks, the type of which would occur in a service failure of a ball bearing, within a steel ball and to closely monitor the properties of this AE from crack initiation to the formation of a ball on the ball surface. It is worth noting that there is evidence that the frequency content of the AE changes during this period, although this has yet to be proved consistent or even fully explained. Conclusive evidence could lead to a system which detects such cracks in a bearing operating in real life conditions, advantageous for many reasons including safety, downtime and maintenance and associated costs. The results from two experimental procedures are presented, one of which loads a single ball held stationary in a test rig to induce subsurface cracks, which are in turn detected by a pair of broadband AE sensors and recorded via a Labview based software system. This approach not only allows detailed analysis of the AE waveforms but also approximate AE source location from the time difference between two sensors. The second experimental procedure details an adaptation of a four-ball lubricant tester in an attempt to produce naturally occurring subsurface cracks from rolling contact whilst minimising the AE arising from surface wear. This thought behind this experiment is reinforced with 3D computational modelling of the rotating system.
12. Effects of boundary conditions on vibrating mode of acoustic logging dipole transducer
2008-01-01
Acoustic transducer is an important part of acoustic well logging tool. In this paper,ANSYS software package is used to design acoustic dipole transducer and simulate vibrating mode of the dipole transducer in different mechanical boundary conditions. The results show that boundary conditions influence the number of vibrating mode in the same frequency band and the frequency value of the same vibrating mode. Several acoustic dipole transducers are designed according to the results of numerical simulation and laboratory measurements. The basic frequency of vibrating mode of experi-ment has good agreement with that of simulation. The numerical simulation plays a good guidance role in designing,producing and correctly installing the acoustic dipole transducer.
13. A survey of acoustic conditions in semi-open plan classrooms in the United Kingdom.
Greenland, Emma E; Shield, Bridget M
2011-09-01
This paper reports the results of a large scale, detailed acoustic survey of 42 open plan classrooms of varying design in the UK each of which contained between 2 and 14 teaching areas or classbases. The objective survey procedure, which was designed specifically for use in open plan classrooms, is described. The acoustic measurements relating to speech intelligibility within a classbase, including ambient noise level, intrusive noise level, speech to noise ratio, speech transmission index, and reverberation time, are presented. The effects on speech intelligibility of critical physical design variables, such as the number of classbases within an open plan unit and the selection of acoustic finishes for control of reverberation, are examined. This analysis enables limitations of open plan classrooms to be discussed and acoustic design guidelines to be developed to ensure good listening conditions. The types of teaching activity to provide adequate acoustic conditions, plus the speech intelligibility requirements of younger children, are also discussed.
14. Fatigue testing of materials under extremal conditions by acoustic method
Baranov, VM; Bibilashvili, YK; Karasevich, VA; Sarychev, GA
2004-01-01
Increasing fuel cycle time requires fatigue testing of the fuel clad materials for nuclear reactors. The standard high-temperature fatigue tests are complicated and tedious. Solving this task is facilitated by the proposed acoustic method, which ensures observation of the material damage dynamics, m
15. Absorption and impedance boundary conditions for phased geometrical-acoustics methods.
Jeong, Cheol-Ho
2012-10-01
Defining accurate acoustical boundary conditions is of crucial importance for room acoustic simulations. In predicting sound fields using phased geometrical acoustics methods, both absorption coefficients and surface impedances of the boundary surfaces can be used, but no guideline has been developed on which boundary condition produces accurate results. In this study, various boundary conditions in terms of normal, random, and field incidence absorption coefficients and normal incidence surface impedance are used in a phased beam tracing model, and the simulated results are validated with boundary element solutions. Two rectangular rooms with uniform and non-uniform absorption distributions are tested. Effects of the neglect of reflection phase shift are also investigated. It is concluded that the impedance, random incidence, and field incidence absorption boundary conditions produce reasonable results with some exceptions at low frequencies for acoustically soft materials.
16. Acoustic conditions in open plan offices – Pilot test results
Witold Mikulski
2016-10-01
Full Text Available Background: The main source of noise in open plan office are conversations. Office work standards in such premises are attained by applying specific acoustic adaptation. This article presents the results of pilot tests and acoustic evaluation of open space rooms. Material and Methods: Acoustic properties of 6 open plan office rooms were the subject of the tests. Evaluation parameters, measurement methods and criterial values were adopted according to the following standards: PN-EN ISO 3382- 3:2012, PN-EN ISO 3382-2:2010, PN-B-02151-4:2015-06 and PN-B-02151-3:2015-10. Results: The reverberation time was 0.33– 0.55 s (maximum permissible value in offices – 0.6 s; the criterion was met, sound absorption coefficient in relation to 1 m2 of the room’s plan was 0.77–1.58 m2 (minimum permissible value – 1.1 m2; 2 out of 6 rooms met the criterion, distraction distance was 8.5–14 m (maximum permissible value – 5 m; none of the rooms met the criterion, A-weighted sound pressure level of speech at a distance of 4 m was 43.8–54.7 dB (maximum permissible value – 48 dB; 2 out of 6 rooms met the criterion, spatial decay rate of the speech was 1.8–6.3 dB (minimum permissible value – 7 dB; none of the rooms met the criterion. Conclusions: Standard acoustic treatment, containing sound absorbing suspended ceiling, sound absorbing materials on the walls, carpet flooring and sound absorbing workplace barriers, is not sufficient. These rooms require specific advanced acoustic solutions. Med Pr 2016;67(5:653–662
17. Assessment of dysphonia due to benign vocal fold lesions by acoustic and aerodynamic indices: a multivariate analysis.
Cantarella, Giovanna; Baracca, Giovanna; Pignataro, Lorenzo; Forti, Stella
2011-04-01
The goal was to identify acoustic and aerodynamic indices that allow the discrimination of a benign organic dysphonic voice from a normal voice. Fifty-three patients affected by dysphonia caused by vocal folds benign lesions, and a control group were subjected to maximum phonation time (MPT) measurements, GRB perceptual evaluations and acoustic/aerodynamic tests. All analyzed variables except the airflow variation coefficient were significantly different between the two groups. The unique significant factors in the discrimination between healthy and dysphonic subjects were the aerodynamic indices of MPT and Glottal efficiency index, and the acoustic index Shimmer. These results show that a combination of three parameters can discriminate a voice deviance and highlight the importance of a multidimensional assessment for objective voice evaluation.
18. Acoustic noise in deep ice and environmental conditions at the South Pole
Karg, Timo
2008-01-01
To study the acoustic properties of the Antarctic ice the South Pole Acoustic Test Setup (SPATS) was installed in the upper part of drill holes for the IceCube neutrino observatory. An important parameter for the design of a future acoustic neutrino telescope is the acoustic background noise in the ice and its spatial and temporal variations. We study the absolute noise level depth profile from SPATS data and discuss systematic uncertainties. The measured noise is very stable over one year of data taking, and we estimate the absolute noise level to be < 10 mPa in the frequency range from 10 kHz to 50 kHz at depths below 200 m. This noise level is of the same order of magnitude as observed by ocean based acoustic neutrino detection projects in good weather conditions.
19. Absorption and impedance boundary conditions for phased geometrical-acoustics methods
Jeong, Cheol-Ho
2012-01-01
Defining accurate acoustical boundary conditions is of crucial importance for room acoustic simulations. In predicting sound fields using phased geometrical acoustics methods, both absorption coefficients and surface impedances of the boundary surfaces can be used, but no guideline has been...... developed on which boundary condition produces accurate results. In this study, various boundary conditions in terms of normal, random, and field incidence absorption coefficients and normal incidence surface impedance are used in a phased beam tracing model, and the simulated results are validated...... with boundary element solutions. Two rectangular rooms with uniform and non-uniform absorption distributions are tested. Effects of the neglect of reflection phase shift are also investigated. It is concluded that the impedance, random incidence, and field incidence absorption boundary conditions produce...
20. Conditions for the Observation of Two Ion-Acoustic Waves via Thomson Scattering
郑坚; 胡广月; 王哲斌; 俞昌旋; 刘万东
2003-01-01
Observation of two ion-acoustic waves via Thomson scattering can provide precise measurements of plasma parameters. The conditions for the observation of two ion-acoustic modes in a two-ion plasmaare discussed.The ratio of electron temperature Te to ion temperature Ti is the critical parameter for the presence of two ion-acoustic modes, which should be in the range of 4/ZL(＜～)Te/Ti(＜～)2AH/ZHAL, where ZL,H are the charge states of light and heavy ions, and AL,H are the atomic numbers of light and heavy ions, respectively. As the temperature ratio varies in this range, the concentration of heavy ions must increase with the ratio Te/Ti so that the two ion-acoustic modes can have the same fluctuation levels.
1. Classroom acoustics design guidelines based on the optimization of speaker conditions
Pelegrin Garcia, David; Brunskog, Jonas
2012-01-01
School teachers suffer frequently from voice problems due to the high vocal load that they experience and the not-always-ideal conditions under which they have to teach. Traditionally, the purpose of the acoustic design of classrooms has been to optimize speech intelligibility. New guidelines...... and noise level measurements in classrooms. Requirements of optimum vocal comfort, average A-weighted speech levels across the audience higher than 50 dB, and a physical volume higher than 6 m3/student are combined to extract optimum acoustic conditions, which depend on the number of students...
2. Damage Characterization of Bio and Green Polyethylene–Birch Composites under Creep and Cyclic Testing with Multivariable Acoustic Emissions
Alencar Bravo
2015-11-01
Full Text Available Despite the knowledge gained in recent years regarding the use of acoustic emissions (AEs in ecologically friendly, natural fiber-reinforced composites (including certain composites with bio-sourced matrices, there is still a knowledge gap in the understanding of the difference in damage behavior between green and biocomposites. Thus, this article investigates the behavior of two comparable green and biocomposites with tests that better reflect real-life applications, i.e., load-unloading and creep testing, to determine the evolution of the damage process. Comparing the mechanical results with the AE, it can be concluded that the addition of a coupling agent (CA markedly reduced the ratio of AE damage to mechanical damage. CA had an extremely beneficial effect on green composites because the Kaiser effect was dominant during cyclic testing. During the creep tests, the use of a CA also avoided the transition to new damaging phases in both composites. The long-term applications of PE green material must be chosen carefully because bio and green composites with similar properties exhibited different damage processes in tests such as cycling and creep that could not be previously understood using only monotonic testing.
3. Thick-film acoustic emission sensors for use in structurally integrated condition-monitoring applications.
Pickwell, Andrew J; Dorey, Robert A; Mba, David
2011-09-01
Monitoring the condition of complex engineering structures is an important aspect of modern engineering, eliminating unnecessary work and enabling planned maintenance, preventing failure. Acoustic emissions (AE) testing is one method of implementing continuous nondestructive structural health monitoring. A novel thick-film (17.6 μm) AE sensor is presented. Lead zirconate titanate thick films were fabricated using a powder/sol composite ink deposition technique and mechanically patterned to form a discrete thick-film piezoelectric AE sensor. The thick-film sensor was benchmarked against a commercial AE device and was found to exhibit comparable responses to simulated acoustic emissions.
4. Acoustical Imaging Cameras for the Inspection and Condition Assessment of Hydraulic Structures
2010-08-01
feasibility of using acoustical imaging for underwater inspection of structures. INTRODUCTION: Visibility in clear water for the human eye and optical ...but higher resolution than sidescan or multibeam acoustical images • Nonhomogeneity of returned signal caused by variation in angles of signals...acoustical imaging. To obtain higher resolutions than other acoustical imaging technologies such as multibeam and sidescan systems, acoustical camera
5. Multivariate analysis comparing microbial air content of an air-conditioned building and a naturally ventilated building over one year
Parat, Sylvie; Perdrix, Alain; Fricker-Hidalgo, Hélène; Saude, Isabelle; Grillot, Renee; Baconnier, Pierre
Heating, ventilation and air-conditioning (HVAC) may be responsible for the production and spread of airborne microorganisms in office buildings. In order to compare airborne microbiological flora in an air-conditioned building with that in a naturally ventilated building, eight sets of measurements were made over a 1-year period. Concurrently with other environmental measurements, air samples were collected in each building, from three offices and from the outdoor air, using the Andersen single-stage sampler. Three different media were used to culture fungi, staphylococci and mesophilic bacteria. Multivariate analysis revealed a group of offices more contaminated than others, and a marked seasonal variation in fungal concentrations. A comparison of mean levels of microorganisms measured in the two buildings showed that the air microbial content was significantly higher and more variable in the naturally ventilated building than in the air-conditioned building. Moreover, in the naturally ventilated building, the interior fungal content was strongly dependent on the outdoor content, while in the air-conditioned building fungal concentrations remained constant despite significant variations measured outside. This was confirmed by a statistical comparison of the correlation coefficients between indoor and outdoor concentrations. No difference was observed regarding gaseous pollutants and temperature, but relative humidity was significantly higher in the air-conditioned building. The effect of HVAC was to prevent the intake of outdoor particles and to dilute the indoor concentrations. These results are consistent with the presence of high-efficiency filters and a steam humidifier in the HVAC system under study.
6. Characterization of acoustic droplet vaporization for control of bubble generation under flow conditions.
Kang, Shih-Tsung; Huang, Yi-Luan; Yeh, Chih-Kuang
2014-03-01
This study investigated the manipulation of bubbles generated by acoustic droplet vaporization (ADV) under clinically relevant flow conditions. Optical microscopy and high-frequency ultrasound imaging were used to observe bubbles generated by 2-MHz ultrasound pulses at different time points after the onset of ADV. The dependence of the bubble population on droplet concentration, flow velocity, fluid viscosity and acoustic parameters, including acoustic pressure, pulse duration and pulse repetition frequency, was investigated. The results indicated that post-ADV bubble growth spontaneously driven by air permeation markedly affected the bubble population after insonation. The bubbles can grow to a stable equilibrium diameter as great as twice the original diameter in 0.5-1 s, as predicted by the theoretical calculation. The growth trend is independent of flow velocity, but dependent on fluid viscosity and droplet concentration, which directly influence the rate of gas uptake by bubbles and the rate of gas exchange across the wall of the semipermeable tube containing the bubbles and, hence, the gas content of the host medium. Varying the acoustic pressure does not markedly change the formation of bubbles as long as the ADV thresholds of most droplets are reached. Varying pulse duration and pulse repetition frequency markedly reduces the number of bubbles. Lengthening pulse duration favors the production of large bubbles, but reduces the total number of bubbles. Increasing the PRF interestingly provides superior performance in bubble disruption. These results also suggest that an ADV bubble population cannot be assessed simply on the basis of initial droplet size or enhancement of imaging contrast by the bubbles. Determining the optimal acoustic parameters requires careful consideration of their impact on the bubble population produced for different application scenarios.
7. Acoustic Emission Analysis of Damage Progression in Thermal Barrier Coatings Under Thermal Cyclic Conditions
Appleby, Matthew; Zhu, Dongming; Morscher, Gregory
2015-01-01
Damage evolution of electron beam-physical vapor deposited (EBVD-PVD) ZrO2-7 wt.% Y2O3 thermal barrier coatings (TBCs) under thermal cyclic conditions was monitored using an acoustic emission (AE) technique. The coatings were heated using a laser heat flux technique that yields a high reproducibility in thermal loading. Along with AE, real-time thermal conductivity measurements were also taken using infrared thermography. Tests were performed on samples with induced stress concentrations, as well as calcium-magnesium-alumino-silicate (CMAS) exposure, for comparison of damage mechanisms and AE response to the baseline (as-produced) coating. Analysis of acoustic waveforms was used to investigate damage development by comparing when events occurred, AE event frequency, energy content and location. The test results have shown that AE accumulation correlates well with thermal conductivity changes and that AE waveform analysis could be a valuable tool for monitoring coating degradation and provide insight on specific damage mechanisms.
8. Acoustic streaming enhances the Multicyclic CO2 capture of natural limestone at Ca-looping conditions.
Valverde, J M; Ebri, J M P; Quintanilla, M A S
2013-08-20
The Ca-Looping (CaL) process, based on the multicyclic carbonation/calcination of CaO at high temperatures, is a viable technology to achieve high CO2 capture efficiencies in both precombustion and postcombustion applications. In this paper we show an experimental study on the multicyclic CO2 capture of a natural limestone in a fixed bed at CaL conditions as affected by the application of a high-intensity acoustic field. Our results indicate that sound promotes the efficiency of CO2 sorption in the fast carbonation phase by enhancing the gas-solids mass transfer. The fundamentals of the physical mechanism responsible for this effect (acoustic streaming) as well as the technical feasibility of the proposed technique allows envisaging that sonoprocessing will be beneficial to enhance multicyclic CO2 capture in large-scale applications.
9. The Harmonic Response Analysis with Acoustic-vibration Coupling of the Combustion Chamber under Different Combustion Conditions
Zheng Min
2016-01-01
Full Text Available In this paper, numerical calculations of harmonic response with acoustic-vibration coupling of the combustion chamber under different combustion conditions has been performed by combining CFD and FEM methods. Temperature and sound pressure fields created by the flame in the combustion chamber are calculated first. And then the results of the CFD are exported to the FEM analysis for the interaction between acoustic waves and wall vibrations. The possible acoustic-vibration coupled eigenfrequencies at given combustion conditions are predicted by the harmonic response analysis.
10. MULTIVARIATE ANALYSIS OF THE DISPLACEMENTS OF A CONCRETE DAM WITH RESPECT TO THE ACTION OF ENVIRONMENTAL CONDITIONS
Sheila Regina Oro
2016-05-01
Full Text Available A review of the concrete dam’s structural performance is a complex issue comprised of many dimensions. This article proposes a method to assist in monitoring the displacements of structures and foundations of dams, considering the action of environmental conditions. Multivariate techniques are used to analyze the data pendulums, extensometer bases and multiple rods extensometer, along with environmental variables of the concrete surface temperature, ambient temperature and the reservoir water level. Specifically applies to Canonical Correlation Analysis to evaluate the influence of environmental variables in the displacement of structures and foundations. Factor Analysis identifies the factors inherent to the variability of the data. This technique makes it possible to order the variables considering the action of factors. This applies also to Cluster Analysis on the data of dates of measurements, according to the similarities present in the observations. Then, Discriminant Analysis evaluates the formed groups for uniformity. The results demonstrate that the method can distinguish the dam responses and identify the effects of variations in environmental conditions over the displacements of structures and foundations.
11. Measurement of impulse peak insertion loss from two acoustic test fixtures and four hearing protector conditions with an acoustic shock tube.
Murphy, William J; Fackler, Cameron J; Berger, Elliott H; Shaw, Peter B; Stergar, Mike
2015-01-01
Impulse peak insertion loss (IPIL) was studied with two acoustic test fixtures and four hearing protector conditions at the E-A-RCAL Laboratory. IPIL is the difference between the maximum estimated pressure for the open-ear condition and the maximum pressure measured when a hearing protector is placed on an acoustic test fixture (ATF). Two models of an ATF manufactured by the French-German Research Institute of Saint-Louis (ISL) were evaluated with high-level acoustic impulses created by an acoustic shock tube at levels of 134 decibels (dB), 150 dB, and 168 dB. The fixtures were identical except that the E-A-RCAL ISL fixture had ear canals that were 3 mm longer than the National Institute for Occupational Safety and Health (NIOSH) ISL fixture. Four hearing protection conditions were tested: Combat Arms earplug with the valve open, ETYPlugs ® earplug, TacticalPro headset, and a dual-protector ETYPlugs earplug with TacticalPro earmuff. The IPILs measured for the E-A-RCAL fixture were 1.4 dB greater than the National Institute for Occupational Safety and Health (NIOSH) ISL ATF. For the E-A-RCAL ISL ATF, the left ear IPIL was 2.0 dB greater than the right ear IPIL. For the NIOSH ATF, the right ear IPIL was 0.3 dB greater than the left ear IPIL.
12. Measurement of impulse peak insertion loss from two acoustic test fixtures and four hearing protector conditions with an acoustic shock tube
William J Murphy
2015-01-01
Full Text Available Impulse peak insertion loss (IPIL was studied with two acoustic test fixtures and four hearing protector conditions at the E-A-RCAL Laboratory. IPIL is the difference between the maximum estimated pressure for the open-ear condition and the maximum pressure measured when a hearing protector is placed on an acoustic test fixture (ATF. Two models of an ATF manufactured by the French-German Research Institute of Saint-Louis (ISL were evaluated with high-level acoustic impulses created by an acoustic shock tube at levels of 134 decibels (dB, 150 dB, and 168 dB. The fixtures were identical except that the E-A-RCAL ISL fixture had ear canals that were 3 mm longer than the National Institute for Occupational Safety and Health (NIOSH ISL fixture. Four hearing protection conditions were tested: Combat Arms earplug with the valve open, ETYPlugs ® earplug, TacticalPro headset, and a dual-protector ETYPlugs earplug with TacticalPro earmuff. The IPILs measured for the E-A-RCAL fixture were 1.4 dB greater than the National Institute for Occupational Safety and Health (NIOSH ISL ATF. For the E-A-RCAL ISL ATF, the left ear IPIL was 2.0 dB greater than the right ear IPIL. For the NIOSH ATF, the right ear IPIL was 0.3 dB greater than the left ear IPIL.
13. Vibro-acoustic characterization of flexible hose in CO2 car air conditioning systems
Angelini, F.; Bergami, A.; Martarelli, M.; Tomasini, E. P.
2008-06-01
Following the EU directive 2006/40/EC proscribing from 2011 that refrigerant fluids must have a global warming potential not higher than 150, it will not be allowed anymore to employ the current R134a on car air conditioning systems. Maflow s.p.a (automotive hose maker) is developing products for each possible new refrigerant. This paper is focused on hoses for CO2 refrigerants operating in the worst conditions because of the high pressures and temperatures at which they are working (with R134a the high pressure is 18 bar and low pressure is 3 bar; with CO2 the high pressure is 100 bar and low pressure is 35 bar). Therefore the noise emission control of the CO2 air conditioning systems is very important. The aim of this study is to develop a standard measurement method for the vibro - acoustic characterization of High Pressure (HP - Shark F4) and Low Pressure (LP - ULEV) hoses to reduce noise emission and raise car passenger comfort; in particular deep research on high pressure hose. The method is based on the measurement of the vibration level of the hoses in a standard test bench by means of a Laser Doppler Vibrometer (LDV) and its acoustic emission by a sound intensity probe.
14. Assessment of infrared spectroscopy and multivariate techniques for monitoring the service condition of diesel-engine lubricating oils.
Caneca, Arnobio Roberto; Pimentel, M Fernanda; Galvão, Roberto Kawakami Harrop; da Matta, Cláudia Eliane; de Carvalho, Florival Rodrigues; Raimundo, Ivo M; Pasquini, Celio; Rohwedder, Jarbas J R
2006-09-15
This paper presents two methodologies for monitoring the service condition of diesel-engine lubricating oils on the basis of infrared spectra. In the first approach, oils samples are discriminated into three groups, each one associated to a given wear stage. An algorithm is proposed to select spectral variables with good discriminant power and small collinearity for the purpose of discriminant analysis classification. As a result, a classification accuracy of 93% was obtained both in the middle (MIR) and near-infrared (NIR) ranges. The second approach employs multivariate calibration methods to predict the viscosity of the lubricant. In this case, the use of absorbance measurements in the NIR spectral range was not successful, because of experimental difficulties associated to the presence of particulate matter. Such a problem was circumvented by the use of attenuated total reflectance (ATR) measurements in the MIR spectral range, in which an RMSEP of 3.8cSt and a relative average error of 3.2% were attained.
15. Influences of an acoustic signal with ultrasound components on the acquisition of a defensive conditioned reflex in Wistar rats.
Loseva, E V; Alekseeva, T G
2007-06-01
The effects of short (90 sec) exposures to a complex acoustic signal with ultrasound components on the acquisition of a defensive conditioned two-way avoidance reflex using an electric shock as the unconditioned stimulus in a shuttle box were studied in female Wistar rats. This stimulus induced audiogenic convulsions of different severities in 59% of the animals. A scale for assessing the ability of rats to acquire the conditioned two-way avoidance reflex was developed. Presentation of the complex acoustic signal was found to be a powerful stressor for Wistar rats, preventing the acquisition of the reflex in the early stages (four and six days) after presentation. This effect was independent of the presence and severity of audiogenic convulsions in the rats during presentation of the acoustic signal. On repeat training nine days after the acoustic signal (with the first session after four days), acquisition of the reflex was hindered (as compared with controls not presented with the acoustic signal). However, on repeat training at later time points (1.5 months after the complex acoustic signal, with the first session after six days), the rats rapidly achieved the learning criterion (10 correct avoidance responses in a row). On the other hand, if the acoustic signal was presented at different times (immediately or at three or 45 days) after the first training session, the animals' ability to acquire the reflex on repeat training was not impaired at either the early or late periods after exposure to the stressor. These results suggest that the complex acoustic signal impairs short-term memory (the process of acquisition of the conditioned two-way avoidance reflex at the early post-presentation time point) but has no effect on long-term memory or consolidation of the memory trace.
16. Analysis of structural - acoustic coupling of elastic rectangular enclosure with arbitrary boundary conditions
2007-01-01
The structural acoustic coupling characteristics of a rectangular enclosure consisting of two elastic supported flexible plates and four rigid plates are analyzed. A general formulation considering the full coupling between the plates and cavity is developed by using Hamiltonian function and Rayleigh-Ritz method. By means of continuous distributions of artificial springs along boundary of flexible plates, a wide variety of boundary conditions and structure joint conditions are considered. To demonstrate the validity of the analytical model,the responses of sound pressure in the cavity and plate velocity are worked out. The analytical results coincides well with Kim's experimental results. The result is satisfactory. Finally, analytical results on the structure vibration and the sound field inside the cavity are presented.These results indicate that the coupling of the combined structure is relatively weak, so the internal cavity sound is controlled by plate directly excited,and the translational stiffness affects the sound more than the rotational stiffness does.
17. Modelling the effects of environmental conditions on the acoustic occurrence and behaviour of Antarctic blue whales.
Shabangu, Fannie W; Yemane, Dawit; Stafford, Kathleen M; Ensor, Paul; Findlay, Ken P
2017-01-01
Harvested to perilously low numbers by commercial whaling during the past century, the large scale response of Antarctic blue whales Balaenoptera musculus intermedia to environmental variability is poorly understood. This study uses acoustic data collected from 586 sonobuoys deployed in the austral summers of 1997 through 2009, south of 38°S, coupled with visual observations of blue whales during the IWC SOWER line-transect surveys. The characteristic Z-call and D-call of Antarctic blue whales were detected using an automated detection template and visual verification method. Using a random forest model, we showed the environmental preferences pattern, spatial occurrence and acoustic behaviour of Antarctic blue whales. Distance to the southern boundary of the Antarctic Circumpolar Current (SBACC), latitude and distance from the nearest Antarctic shores were the main geographic predictors of blue whale call occurrence. Satellite-derived sea surface height, sea surface temperature, and productivity (chlorophyll-a) were the most important environmental predictors of blue whale call occurrence. Call rates of D-calls were strongly predicted by the location of the SBACC, latitude and visually detected number of whales in an area while call rates of Z-call were predicted by the SBACC, latitude and longitude. Satellite-derived sea surface height, wind stress, wind direction, water depth, sea surface temperatures, chlorophyll-a and wind speed were important environmental predictors of blue whale call rates in the Southern Ocean. Blue whale call occurrence and call rates varied significantly in response to inter-annual and long term variability of those environmental predictors. Our results identify the response of Antarctic blue whales to inter-annual variability in environmental conditions and highlighted potential suitable habitats for this population. Such emerging knowledge about the acoustic behaviour, environmental and habitat preferences of Antarctic blue whales is
18. Modelling the effects of environmental conditions on the acoustic occurrence and behaviour of Antarctic blue whales
Shabangu, Fannie W.; Yemane, Dawit; Stafford, Kathleen M.; Ensor, Paul; Findlay, Ken P.
2017-01-01
Harvested to perilously low numbers by commercial whaling during the past century, the large scale response of Antarctic blue whales Balaenoptera musculus intermedia to environmental variability is poorly understood. This study uses acoustic data collected from 586 sonobuoys deployed in the austral summers of 1997 through 2009, south of 38°S, coupled with visual observations of blue whales during the IWC SOWER line-transect surveys. The characteristic Z-call and D-call of Antarctic blue whales were detected using an automated detection template and visual verification method. Using a random forest model, we showed the environmental preferences pattern, spatial occurrence and acoustic behaviour of Antarctic blue whales. Distance to the southern boundary of the Antarctic Circumpolar Current (SBACC), latitude and distance from the nearest Antarctic shores were the main geographic predictors of blue whale call occurrence. Satellite-derived sea surface height, sea surface temperature, and productivity (chlorophyll-a) were the most important environmental predictors of blue whale call occurrence. Call rates of D-calls were strongly predicted by the location of the SBACC, latitude and visually detected number of whales in an area while call rates of Z-call were predicted by the SBACC, latitude and longitude. Satellite-derived sea surface height, wind stress, wind direction, water depth, sea surface temperatures, chlorophyll-a and wind speed were important environmental predictors of blue whale call rates in the Southern Ocean. Blue whale call occurrence and call rates varied significantly in response to inter-annual and long term variability of those environmental predictors. Our results identify the response of Antarctic blue whales to inter-annual variability in environmental conditions and highlighted potential suitable habitats for this population. Such emerging knowledge about the acoustic behaviour, environmental and habitat preferences of Antarctic blue whales is
19. Elastic contact conditions to optimize friction drive of surface acoustic wave motor.
Kuribayashi Kurosawa, M; Takahashi, M; Higuchi, T
1998-01-01
The optimum pressing force, namely the preload, for a slider to obtain superior operation conditions in a surface acoustic wave motor have been examined. We used steel balls as sliders. The preload was controlled using a permanent magnet. The steel balls were 0.5, 1, and 2 mm diameter, with the differences in diameter making it possible to change contact conditions, such as the contact pressure, contact area, and deformation of the stator and the slider. The stator transducer was lithium niobate, 128 degrees rotated, y-cut x-propagation substrate. The driving frequency of the Rayleigh wave was about 10 MHz. Hence, the particle vibration amplitude at the surface is as small as 10 nm. For superior friction drive conditions, a high contact pressure was required. For example, in the case of the 1 mm diameter steel ball at the sinusoidal driving voltage of 180 V(peak), the slider speed was 43 cm/sec, the thrust output force was 1 mN, and the acceleration was 23 times as large as the gravitational acceleration at a contact pressure of 390 MPa. From the Hertz theory of contact stress, the contact area radius was only 3 microm. The estimation of the friction drive performance was carried out from the transient traveling distance of the slider in a 3 msec burst drive. As a result, the deformation of the stator and the slider by the preload should be half of the vibration amplitude. This condition was independent of the ball diameter and the vibration amplitude. The output thrust per square millimeter was 50 N, and the maximum speed was 0.7 m/sec. From these results, we conclude that it is possible for the surface acoustic wave motor to have a large output force, high speed, quick response, long traveling distance, and a thin micro linear actuator.
20. An efficient realization of frequency dependent boundary conditions in an acoustic finite-difference time-domain model
Escolano-Carrasco, José; Jacobsen, Finn; López, J.J.
2008-01-01
The finite-difference time-domain (FDTD) method provides a simple and accurate way of solving initial boundary value problems. However, most acoustic problems involve frequency dependent boundary conditions, and it is not easy to include such boundary conditions in an FDTD model. Although solutions...
1. Acoustic emission-based condition monitoring methods: Review and application for low speed slew bearing
Caesarendra, Wahyu; Kosasih, Buyung; Tieu, Anh Kiet; Zhu, Hongtao; Moodie, Craig A. S.; Zhu, Qiang
2016-05-01
This paper presents an acoustic emission-based method for the condition monitoring of low speed reversible slew bearings. Several acoustic emission (AE) hit parameters as the monitoring parameters for the detection of impending failure of slew bearings are reviewed first. The review focuses on: (1) the application of AE in typical rolling element bearings running at different speed classifications, i.e. high speed (>600 rpm), low speed (10-600 rpm) and very low speed (<10 rpm); (2) the commonly used AE hit parameters in rolling element bearings and (3) AE signal processing, feature extraction and pattern recognition methods. In the experiment, impending failure of the slew bearing was detected by the AE hit parameters after the new bearing had run continuously for approximately 15 months. The slew bearing was then dismantled and the evidence of the early defect was analysed. Based on the result, we propose a feature extraction method of the AE waveform signal using the largest Lyapunov exponent (LLE) algorithm and demonstrate that the LLE feature can detect the sign of failure earlier than the AE hit parameters with improved prediction of the progressive trend of the defect.
2. High order local absorbing boundary conditions for acoustic waves in terms of farfield expansions
Villamizar, Vianey; Acosta, Sebastian; Dastrup, Blake
2017-03-01
We devise a new high order local absorbing boundary condition (ABC) for radiating problems and scattering of time-harmonic acoustic waves from obstacles of arbitrary shape. By introducing an artificial boundary S enclosing the scatterer, the original unbounded domain Ω is decomposed into a bounded computational domain Ω- and an exterior unbounded domain Ω+. Then, we define interface conditions at the artificial boundary S, from truncated versions of the well-known Wilcox and Karp farfield expansion representations of the exact solution in the exterior region Ω+. As a result, we obtain a new local absorbing boundary condition (ABC) for a bounded problem on Ω-, which effectively accounts for the outgoing behavior of the scattered field. Contrary to the low order absorbing conditions previously defined, the error at the artificial boundary induced by this novel ABC can be easily reduced to reach any accuracy within the limits of the computational resources. We accomplish this by simply adding as many terms as needed to the truncated farfield expansions of Wilcox or Karp. The convergence of these expansions guarantees that the order of approximation of the new ABC can be increased arbitrarily without having to enlarge the radius of the artificial boundary. We include numerical results in two and three dimensions which demonstrate the improved accuracy and simplicity of this new formulation when compared to other absorbing boundary conditions.
3. Multivariate Generalized Autoregressive Conditional Heteroscedastic Model%多维广义自回归条件异方差模型
史宁中; 刘继春
2001-01-01
In this paper, by making use of the Hadamard product of matrices, a natural and reasonable generalization of the univariate GARCH (Generalized Autoregressive Conditional heteroscedastic) process introduced by Bollerslev (J. Econometrics 31(1986), 307-327) to the multivariate case is proposed. The conditions for the existence of strictly stationary and ergodic solutions and the existence of higherorder moments for this class of parametric models are derived.
4. Vowel Acoustics in Parkinson's Disease and Multiple Sclerosis: Comparison of Clear, Loud, and Slow Speaking Conditions
Tjaden, Kris; Lam, Jennifer; Wilding, Greg
2013-01-01
Purpose: The impact of clear speech, increased vocal intensity, and rate reduction on acoustic characteristics of vowels was compared in speakers with Parkinson's disease (PD), speakers with multiple sclerosis (MS), and healthy controls. Method: Speakers read sentences in habitual, clear, loud, and slow conditions. Variations in clarity,…
5. Comprehensive bearing condition monitoring algorithm for incipient fault detection using acoustic emission
Amit R. Bhende
2014-09-01
Full Text Available The bearing reliability plays major role in obtaining the desired performance of any machine. A continuous condition monitoring of machine is required in certain applications where failure of machine leads to loss of production, human safety and precision. Machine faults are often linked to the bearing faults. Condition monitoring of machine involves continuous watch on the performance of bearings and predicting the faults of bearing before it cause any adversity. This paper investigates an experimental study to diagnose the fault while bearing is in operation. An acoustic emission technique is used in the experimentation. An algorithm is developed to process various types of signals generated from different bearing defects. The algorithm uses time domain analysis along with combination low frequency analysis technique such as fast Fourier transform and high frequency envelope detection. Two methods have adopted for envelope detection which are Hilbert transform and order analysis. Experimental study is carried out for deep groove ball bearing cage defect. Results show the potential effectiveness of the proposed algorithm to determine presence of fault, exact location and severity of fault.
6. Acoustic signal detection through the cross-correlation method in experiments with different signal to noise ratio and reverberation conditions
Adrián-Martínez, S; Bou-Cabo, M; Felis, I; Llorens, C; Martínez-Mora, J A; Saldaña, M
2015-01-01
The study and application of signal detection techniques based on cross-correlation method for acoustic transient signals in noisy and reverberant environments are presented. These techniques are shown to provide high signal to noise ratio, good signal discernment from very close echoes and accurate detection of signal arrival time. The proposed methodology has been tested on real data collected in environments and conditions where its benefits can be shown. This work focuses on the acoustic detection applied to tasks of positioning in underwater structures and calibration such those as ANTARES and KM3NeT deep-sea neutrino telescopes, as well as, in particle detection through acoustic events for the COUPP/PICO detectors. Moreover, a method for obtaining the real amplitude of the signal in time (voltage) by using cross correlation has been developed and tested and is described in this work.
7. Crystal Growth in Al72.9Ge27.1 Alloy Melt under Acoustic Levitation Conditions
YAN Na; DAI Fu-Ping; WANG Wei-Li; WEI Bing-Bo
2011-01-01
The nonequilibrium solidification of liquid Al72.9Ge27.1 hypoeutectic alloy is accomplished by using single-axis acoustic levitation.A maximum undercooling of 112K (0.16TL) is obtained for the alloy melt at a coofing rate of 50 K/s. The primary (Al) phase displays a morphological transition from coarse dendrite under a normal conditions to equiaxed grain under acoustic levitation.In the (Al)+(Ge) eutectic,the (Ge) phase exhibits a conspicuous branched growth morphology.Both the primary (Al) dendrites and (Al)+(Ge) eutectics are well refined and the solute content of the primary (Al) phase is extended under acoustic levitation.The calculated and experimental results indicate that the solute trapping effect becomes more intensive with the enhancement of bulk undercooling.
8. Acoustic environment challenges for the unique communication conditions in group learning classes in elementary school classrooms
Sutherland, Louis; Lubman, David; Pearsons, Karl
2005-04-01
Unlike the traditional sage-on-the-stage'' configuration of many K-12 classrooms, the group learning or guide-on-the-side'' configuration does not involve communication between a teacher in front of a seated class of 20 to 30 students. Instead, it can involve, most of the time, communication between the teacher and each of several small groups of students interacting, aurally, with each other. To maintain the desired 15 dB signal-to-noise ratio intended as the rationale for the ANSI standard, S12.60-2002 on classroom acoustics, the noise'' heard by participants in one of the groups is likely to include the speech levels generated by the participants in the other groups as well as the background noise in the unoccupied classroom. Thus, specification of the speech level within (i.e. the signal''), and between (i.e. part of the noise'') the learning groups, must be considered. Data available to evaluate these speech levels are reviewed and possible models considered to account for the Lombard effect for voice levels of both the teacher and the students. Some of the gaps in these data are suggested as a challenge to stimulate further studies on speech levels of teachers and students in a wide range of communication conditions.
9. Recent developments on surface acoustic wave (SAW) sensors for harsh conditions
Schiopu, Paul; Chilibon, Irinela; Grosu, Neculai; Craciun, Alexandru
2015-02-01
The results of research into Surface Acoustic Waves (SAW) devices have been recognized for their efficiency and versatility in the electrical signals processing. Actual progress in the industrial application of piezoelectric materials such as Lithium Niobate (LiNbO3), Langasite (LGS), Lanthanum-Gallium Silicate La3Ga5SiO14 and Gallium Orthophosphate (GaPO4), allows the manufacturing of devices with piezoelectric performances, which overcome the limits obtained with quartz crystals. The single crystal materials have a long term high stability - near to infinite - and moreover, some of these have an excellent behavior with temperature variation. Today, GaPO4 with its properties is by far the best suited piezoelectric material to be used in sensor applications for machine monitoring and pressure measurements, at high temperatures. SAW micro devices based on GaPO4 operate at temperatures of up to 8000C. For a particular case, of harsh-environment applications, additional challenges need to be overcome, relating to substrate integrity and operation, thin film electrode fabrication, device packaging, and sensor interrogation. This paper reviews the novel progres in the area of (SAW) sensors for harsh conditions.
10. A Correction of Random Incidence Absorption Coefficients for the Angular Distribution of Acoustic Energy under Measurement Conditions
Jeong, Cheol-Ho
2009-01-01
Most acoustic measurements are based on an assumption of ideal conditions. One such ideal condition is a diffuse and reverberant field. In practice, a perfectly diffuse sound field cannot be achieved in a reverberation chamber. Uneven incident energy density under measurement conditions can cause...... discrepancies between the measured value and the theoretical random incidence absorption coefficient. Therefore the angular distribution of the incident acoustic energy onto an absorber sample should be taken into account. The angular distribution of the incident energy density was simulated using the beam...... the theoretical absorption coefficient and the reverberation room measurement. The angle-weighted absorption coefficient, together with the size correction, agrees satisfactorily with the measured absorption data by the reverberation chamber method. At high frequencies and for large samples, the averaged...
11. A surface acoustic wave-driven micropump for particle uptake investigation under physiological flow conditions in very small volumes
Florian G. Strobl
2015-02-01
Full Text Available Static conditions represent an important shortcoming of many in vitro experiments on the cellular uptake of nanoparticles. Here, we present a versatile microfluidic device based on acoustic streaming induced by surface acoustic waves (SAWs. The device offers a convenient method for introducing fluid motion in standard cell culture chambers and for mimicking capillary blood flow. We show that shear rates over the whole physiological range in sample volumes as small as 200 μL can be achieved. A precise characterization method for the induced flow profile is presented and the influence of flow on the uptake of Pt-decorated CeO2 particles by endothelial cells (HMEC-1 is demonstrated. Under physiological flow conditions the particle uptake rates for this system are significantly lower than at low shear conditions. This underlines the vital importance of the fluidic environment for cellular uptake mechanisms.
12. A methodology to condition distorted acoustic emission signals to identify fracture timing from human cadaver spine impact tests.
Arun, Mike W J; Yoganandan, Narayan; Stemper, Brian D; Pintar, Frank A
2014-12-01
While studies have used acoustic sensors to determine fracture initiation time in biomechanical studies, a systematic procedure is not established to process acoustic signals. The objective of the study was to develop a methodology to condition distorted acoustic emission data using signal processing techniques to identify fracture initiation time. The methodology was developed from testing a human cadaver lumbar spine column. Acoustic sensors were glued to all vertebrae, high-rate impact loading was applied, load-time histories were recorded (load cell), and fracture was documented using CT. Compression fracture occurred to L1 while other vertebrae were intact. FFT of raw voltage-time traces were used to determine an optimum frequency range associated with high decibel levels. Signals were bandpass filtered in this range. Bursting pattern was found in the fractured vertebra while signals from other vertebrae were silent. Bursting time was associated with time of fracture initiation. Force at fracture was determined using this time and force-time data. The methodology is independent of selecting parameters a priori such as fixing a voltage level(s), bandpass frequency and/or using force-time signal, and allows determination of force based on time identified during signal processing. The methodology can be used for different body regions in cadaver experiments.
13. STUDIES OF ACOUSTIC EMISSION SIGNATURES FOR QUALITY ASSURANCE OF SS 316L WELDED SAMPLES UNDER DYNAMIC LOAD CONDITIONS
S. V. RANGANAYAKULU
2016-10-01
Full Text Available Acoustic Emission (AE signatures of various weld defects of stainless steel 316L nuclear grade weld material are investigated. The samples are fabricated by Tungsten Inert Gas (TIG Welding Method have final dimension of 140 mm x 15 mm x 10 mm. AE signals from weld defects such as Pinhole, Porosity, Lack of Penetration, Lack of Side Fusion and Slag are recorded under dynamic load conditions by specially designed mechanical jig. AE features of the weld defects were attained using Linear Location Technique (LLT. The results from this study concluded that, stress release and structure deformation between the sections in welding area are load conditions major part of Acoustic Emission activity during loading.
14. Enhancement of acoustic prepulse inhibition by contextual fear conditioning in mice is maintained even after contextual fear extinction.
Ishii, Daisuke; Matsuzawa, Daisuke; Fujita, Yuko; Sutoh, Chihiro; Ohtsuka, Hiroyuki; Matsuda, Shingo; Kanahara, Nobuhisa; Hashimoto, Kenji; Iyo, Masaomi; Shimizu, Eiji
2010-02-01
Prepulse inhibition (PPI) of the acoustic startle response is one of the few and major paradigms for investigating sensorimotor gating systems in humans and rodents in a similar fashion. PPI deficits are observed not only in patients with schizophrenia, but also in patients with anxiety disorders. Previous studies have shown that PPI in rats can be enhanced by auditory fear conditioning. In this study, we evaluated the effects of contextual fear conditioning (FC) for six times a day and fear extinction (FE) for seven days on PPI in mice. C57BL/6J mice (male, 8-12 weeks) were divided into three groups; no-FC (control), FC and FC + FE. We measured PPI at the following three time points, (1) baseline before FC, (2) after FC, and (3) after FE. The results showed that PPI was increased after FC. Moreover, the enhanced PPI following FC was observed even after FE with decreased freezing behaviors. These results suggested contextual fear conditioning could enhance acoustic PPI, and that contextual fear extinction could decrease freezing behaviors, but not acoustic PPI.
15. Discussions about Calculation of Conditional Extreme of Multivariate Function%多元函数条件极值的求法探究
方倩珊; 吴全荣
2014-01-01
Combined with examples, this paper first discussed six methods about calculation of conditional extreme of multivariate function: the substitution elimination method, the Lagrange multiplier method, the geometrical model method, the parametric equation method, the gradient inner product method, inequality method. And then it analyzed applicable condition of various calculation methods and pointed out the non-precise aspects in some textbooks about calculation of conditional extreme of multivariate function in order to help students choose the appropriate method when solving such problems.%结合具体实例，分别从代入消元法、拉格朗日乘数法、几何模型法、参数方程法、梯度内积法、不等式法等六个角度探讨了多元函数条件极值的多种求法，比较了各种求法适用的条件，并指出某些教材中多元函数条件极值求法的不严谨性。旨在帮助学生在求解此类问题时选择适当的方法，把握正确的解题方向。
16. Experimental investigation of the effects of the acoustical conditions in a simulated classroom on speech recognition and learning in children.
Valente, Daniel L; Plevinsky, Hallie M; Franco, John M; Heinrichs-Graham, Elizabeth C; Lewis, Dawna E
2012-01-01
The potential effects of acoustical environment on speech understanding are especially important as children enter school where students' ability to hear and understand complex verbal information is critical to learning. However, this ability is compromised because of widely varied and unfavorable classroom acoustics. The extent to which unfavorable classroom acoustics affect children's performance on longer learning tasks is largely unknown as most research has focused on testing children using words, syllables, or sentences as stimuli. In the current study, a simulated classroom environment was used to measure comprehension performance of two classroom learning activities: a discussion and lecture. Comprehension performance was measured for groups of elementary-aged students in one of four environments with varied reverberation times and background noise levels. The reverberation time was either 0.6 or 1.5 s, and the signal-to-noise level was either +10 or +7 dB. Performance is compared to adult subjects as well as to sentence-recognition in the same condition. Significant differences were seen in comprehension scores as a function of age and condition; both increasing background noise and reverberation degraded performance in comprehension tasks compared to minimal differences in measures of sentence-recognition.
17. Passive Acoustic Detection of Wind Turbine In-Flow Conditions for Active Control and Optimization
Murray, Nathan E.
2012-03-12
Wind is a significant source of energy; however, the human capability to produce electrical energy still has many hurdles to overcome. One of these is the unpredictability of the winds in the atmospheric boundary layer (ABL). The ABL is highly turbulent in both stable and unstable conditions (based on the vertical temperature profile) and the resulting fluctuations can have a dramatic impact on wind turbine operation. Any method by which these fluctuations could be observed, estimated, or predicted could provide a benefit to the wind energy industry as a whole. Based on the fundamental coupling of velocity fluctuations to pressure fluctuations in the nearly incompressible flow in the ABL, This work hypothesizes that a ground-based array of infrasonic pressure transducers could be employed to estimate the vertical wind profile over a height relevant for wind turbines. To analyze this hypothesis, experiments and field deployments were conducted. Wind tunnel experiments were performed for a thick turbulent boundary layer over a neutral or heated surface. Surface pressure and velocity probe measurements were acquired simultaneously. Two field deployments yielded surface pressure data from a 49 element array. The second deployment at the Reese Technology Center in Lubbock, TX, also included data from a smaller aperture, 96-element array and a 200-meter tall meteorological tower. Analysis of the data successfully demonstrated the ability to estimate the vertical velocity profile using coherence data from the pressure array. Also, dynamical systems analysis methods were successful in identifying and tracking a gust type event. In addition to the passive acoustic profiling method, this program also investigated a rapid response Doppler SODAR system, the optimization of wind turbine blades for enhanced power with reduced aeroacoustic noise production, and the implementation of a wireless health monitoring system for the wind turbine blades. Each of these other objectives
18. Speech intelligibility for normal hearing and hearing-impaired listeners in simulated room acoustic conditions
Arweiler, Iris; Dau, Torsten; Poulsen, Torben
, a classroom and a church. The data from the study provide constraints for existing models of speech intelligibility prediction (based on the speech intelligibility index, SII, or the speech transmission index, STI) which have shortcomings when reverberation and/or fluctuating noise affect speech......Speech intelligibility depends on many factors such as room acoustics, the acoustical properties and location of the signal and the interferers, and the ability of the (normal and impaired) auditory system to process monaural and binaural sounds. In the present study, the effect of reverberation...... on spatial release from masking was investigated in normal hearing and hearing impaired listeners using three types of interferers: speech shaped noise, an interfering female talker and speech-modulated noise. Speech reception thresholds (SRT) were obtained in three simulated environments: a listening room...
19. Central amygdala lesions inhibit pontine nuclei acoustic reactivity and retard delay eyeblink conditioning acquisition in adult rats.
Pochiro, Joseph M; Lindquist, Derick H
2016-06-01
In delay eyeblink conditioning (EBC) a neutral conditioned stimulus (CS; tone) is repeatedly paired with a mildly aversive unconditioned stimulus (US; periorbital electrical shock). Over training, subjects learn to produce an anticipatory eyeblink conditioned response (CR) during the CS, prior to US onset. While cerebellar synaptic plasticity is necessary for successful EBC, the amygdala is proposed to enhance eyeblink CR acquisition. In the current study, adult Long-Evans rats received bilateral sham or neurotoxic lesions of the central nucleus of the amygdala (CEA) followed by 1 or 4 EBC sessions. Fear-evoked freezing behavior, CS-mediated enhancement of the unconditioned response (UR), and eyeblink CR acquisition were all impaired in the CEA lesion rats relative to sham controls. There were also significantly fewer c-Fos immunoreactive cells in the pontine nuclei (PN)-major relays of acoustic information to the cerebellum-following the first and fourth EBC session in lesion rats. In sham rats, freezing behavior decreased from session 1 to 4, commensurate with nucleus-specific reductions in amygdala Fos+ cell counts. Results suggest delay EBC proceeds through three stages: in stage one the amygdala rapidly excites diffuse fear responses and PN acoustic reactivity, facilitating cerebellar synaptic plasticity and the development of eyeblink CRs in stage two, leading, in stage three, to a diminution or stabilization of conditioned fear responding.
Lyamshev, Leonid M
2004-01-01
1. Stability conditions of the Vistula Valley attained by a multivariate approach - a case study from the Warsaw Southern Ring Road
Kaczmarek, Łukasz; Dobak, Paweł
2015-12-01
Localised landslide activity has been observed in the area of the plateau slope analysed, in the vicinity of the planned Warsaw Southern Ring Road. Using calculation models quantitative and qualitative evaluations of the impact of natural and anthropogenic load factors on slope stability (and hence, safety) are made. The present paper defines six stages of slope stability analysis, leading to an indication of optimum slope design in relation to the development planned. The proposed procedure produces a ranking of factors that affect slope stability. In the engineering geological conditions under consideration, the greatest factors impacting degradation and failure of slope stability are changes in soil strength due to local, periodic yielding and the presence of dynamic loads generated by intensification of road traffic. Calculation models were used to assess the impact of destabilisation factors and to obtain mutual equivalence with 3D-visualisation relations. Based on this methodology, various scenarios dedicated to specific engineering geological conditions can be developed and rapid stability evaluations of changing slope loads can be performed.
2. Acoustic dose and acoustic dose-rate.
Duck, Francis
2009-10-01
Acoustic dose is defined as the energy deposited by absorption of an acoustic wave per unit mass of the medium supporting the wave. Expressions for acoustic dose and acoustic dose-rate are given for plane-wave conditions, including temporal and frequency dependencies of energy deposition. The relationship between the acoustic dose-rate and the resulting temperature increase is explored, as is the relationship between acoustic dose-rate and radiation force. Energy transfer from the wave to the medium by means of acoustic cavitation is considered, and an approach is proposed in principle that could allow cavitation to be included within the proposed definitions of acoustic dose and acoustic dose-rate.
3. Room Acoustics
Kuttruff, Heinrich; Mommertz, Eckard
The traditional task of room acoustics is to create or formulate conditions which ensure the best possible propagation of sound in a room from a sound source to a listener. Thus, objects of room acoustics are in particular assembly halls of all kinds, such as auditoria and lecture halls, conference rooms, theaters, concert halls or churches. Already at this point, it has to be pointed out that these conditions essentially depend on the question if speech or music should be transmitted; in the first case, the criterion for transmission quality is good speech intelligibility, in the other case, however, the success of room-acoustical efforts depends on other factors that cannot be quantified that easily, not least it also depends on the hearing habits of the listeners. In any case, absolutely "good acoustics" of a room do not exist.
4. An Alternative Flight Software Trigger Paradigm: Applying Multivariate Logistic Regression to Sense Trigger Conditions Using Inaccurate or Scarce Information
Smith, Kelly M.; Gay, Robert S.; Stachowiak, Susan J.
2013-01-01
In late 2014, NASA will fly the Orion capsule on a Delta IV-Heavy rocket for the Exploration Flight Test-1 (EFT-1) mission. For EFT-1, the Orion capsule will be flying with a new GPS receiver and new navigation software. Given the experimental nature of the flight, the flight software must be robust to the loss of GPS measurements. Once the high-speed entry is complete, the drogue parachutes must be deployed within the proper conditions to stabilize the vehicle prior to deploying the main parachutes. When GPS is available in nominal operations, the vehicle will deploy the drogue parachutes based on an altitude trigger. However, when GPS is unavailable, the navigated altitude errors become excessively large, driving the need for a backup barometric altimeter to improve altitude knowledge. In order to increase overall robustness, the vehicle also has an alternate method of triggering the parachute deployment sequence based on planet-relative velocity if both the GPS and the barometric altimeter fail. However, this backup trigger results in large altitude errors relative to the targeted altitude. Motivated by this challenge, this paper demonstrates how logistic regression may be employed to semi-automatically generate robust triggers based on statistical analysis. Logistic regression is used as a ground processor pre-flight to develop a statistical classifier. The classifier would then be implemented in flight software and executed in real-time. This technique offers improved performance even in the face of highly inaccurate measurements. Although the logistic regression-based trigger approach will not be implemented within EFT-1 flight software, the methodology can be carried forward for future missions and vehicles.
5. An Alternative Flight Software Paradigm: Applying Multivariate Logistic Regression to Sense Trigger Conditions using Inaccurate or Scarce Information
Smith, Kelly; Gay, Robert; Stachowiak, Susan
2013-01-01
In late 2014, NASA will fly the Orion capsule on a Delta IV-Heavy rocket for the Exploration Flight Test-1 (EFT-1) mission. For EFT-1, the Orion capsule will be flying with a new GPS receiver and new navigation software. Given the experimental nature of the flight, the flight software must be robust to the loss of GPS measurements. Once the high-speed entry is complete, the drogue parachutes must be deployed within the proper conditions to stabilize the vehicle prior to deploying the main parachutes. When GPS is available in nominal operations, the vehicle will deploy the drogue parachutes based on an altitude trigger. However, when GPS is unavailable, the navigated altitude errors become excessively large, driving the need for a backup barometric altimeter to improve altitude knowledge. In order to increase overall robustness, the vehicle also has an alternate method of triggering the parachute deployment sequence based on planet-relative velocity if both the GPS and the barometric altimeter fail. However, this backup trigger results in large altitude errors relative to the targeted altitude. Motivated by this challenge, this paper demonstrates how logistic regression may be employed to semi-automatically generate robust triggers based on statistical analysis. Logistic regression is used as a ground processor pre-flight to develop a statistical classifier. The classifier would then be implemented in flight software and executed in real-time. This technique offers improved performance even in the face of highly inaccurate measurements. Although the logistic regression-based trigger approach will not be implemented within EFT-1 flight software, the methodology can be carried forward for future missions and vehicles
6. Multivariate Modelling via Matrix Subordination
Nicolato, Elisa
stochastic volatility via time-change is quite ineffective when applied to the multivariate setting. In this work we propose a new class of models, which is obtained by conditioning a multivariate Brownian Motion to a so-called matrix subordinator. The obtained model-class encompasses the vast majority...
7. Distribution of small dispersive coal dust particles and absorbed radioactive chemical elements in conditions of forced acoustic resonance in iodine air filter at nuclear power plant
Ledenyov, Oleg P
2013-01-01
The physical features of distribution of the small dispersive coal dust particles and the adsorbed radioactive chemical elements and their isotopes in the absorber with the granular filtering medium with the cylindrical coal granules were researched in the case of the intensive air dust aerosol stream flow through the iodine air filter (IAF). It was shown that, at the certain aerodynamic conditions in the IAF, the generation of the acoustic oscillations is possible. It was found that the acoustic oscillations generation results in an appearance of the standing acoustic waves of the air pressure (density) in the IAF. In the case of the intensive blow of the air dust aerosol, it was demonstrated that the standing acoustic waves have some strong influences on both: 1) the dynamics of small dispersive coal dust particles movement and their accumulation in the IAF; 2) the oversaturation of the cylindrical coal granules by the adsorbed radioactive chemical elements and their isotopes in the regions, where the antin...
8. Supervised and unsupervised condition monitoring of non-stationary acoustic emission signals
Sigurdsson, Sigurdur; Pontoppidan, Niels Henrik; Larsen, Jan
2005-01-01
We are pursuing a system that monitors the engine condition under multiple load settings, i.e. under non-stationary operating conditions. The running speed when data acquired under simulated marine conditions (different load settings on the propeller curve) was in the range from approximately 70...... approaches perform well, which indicates that unsupervised models, modelled without faulty data, may be used for accurate condition monitoring....... condition changes across load changes. In this paper we approach this load interpolation problem with supervised and unsupervised learning, i.e. model with normal and fault examples and normal examples only, respectively. We apply non-linear methods for the learning of engine condition changes. Both...
9. Acoustic boundary conditions at an impedance lining in inviscid shear flow
Khamis, Doran; Brambley, Edward James
2016-01-01
This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by Cambridge University Press. The accuracy of existing impedance boundary conditions is investigated, and new impedance boundary conditions are derived, for lined ducts with inviscid shear flow. The accuracy of the Ingard–Myers boundary condition is found to be poor. Matched asymptotic expansions are used to derive a boundary condition accurate to second order in the boundary layer thic...
10. Responsive acoustic surfaces
Peters, Brady; Tamke, Martin; Nielsen, Stig Anton;
2011-01-01
Acoustic performance is defined by the parameter of reverberation time; however, this does not capture the acoustic experience in some types of open plan spaces. As many working and learning activities now take place in open plan spaces, it is important to be able to understand and design...... for the acoustic conditions of these spaces. This paper describes an experimental research project that studied the design processes necessary to design for sound. A responsive acoustic surface was designed, fabricated and tested. This acoustic surface was designed to create specific sonic effects. The design...... was simulated using custom integrated acoustic software and also using Odeon acoustic analysis software. The research demonstrates a method for designing space- and sound-defining surfaces, defines the concept of acoustic subspace, and suggests some new parameters for defining acoustic subspaces....
11. 基于条件概率积分变换的多元Copula函数选择%Selection for Multivariate Copula Based on Conditional Probability Integral Transformation
王宗润; 汪武超; 王小丁; 周艳菊
2012-01-01
本文构建了基于条件概率积分变换的Copula函数选择方法,通过对条件概率积分变换下Anderson-Darling( AD)、Kolmogorov-Smirnov (KS)、Cramér-von Mises (CM)这三种统计量的比较,讨论在不同样本容量和变量维数下其对多种Copula函数的拟合效果.利用GSPTSE、INMEX.MX和NDX三大股指样本,将基于条件概率积分变换的Copula函数选择方法与核密度估计和极大似然估计选择法的效果进行系统比较.结果表明,基于条件概率积分变换的检验法可以有效解决多元Copula函数的选择问题,其拟舍优度检验更精确、更稳定；核密度估计检验在大样本下比较稳定,而小样本下稳定性较差；相比之下,极大似然值检验法则不稳定.%The dependence structure among multivariate financial assets is a critical factor for achieving accuracy in the integrated risk measurement. Copula function is a very useful tool to describe the dependence structure between risk factors and plays an important role in the field of financial risk management. When using the Copula model, the most important thing is to judge which Copula is more suitable to describe the data dependence structure. Therefore, it is very important to do research on the selection criteria of multivariate Copula models and the goodness-of-fit test methods. However, in the field of financial risk management, most of the research has focused on bivariate cases. There is very little research on the goodness-of-fit and empirical analysis on the multivariate cases. There is still no effective solutions for the selection and goodness-of-fit test of multivariate Copula functions. Therefore, this paper proposes a selection criterion for Copula's goodness-of-fit based on the method of conditional probability integral transformation. We analyze and compare the Anderson-Darling ( AD) , Kolmogorov-Smirnov ( KS) and Cram6r-von Mises (CM) test statistics under the CPIT method with various sample sizes and
12. Repeated elicitation of the acoustic startle reflex leads to sensitisation in subsequent avoidance behaviour and induces fear conditioning
Janik Vincent M
2011-04-01
Full Text Available Abstract Background Autonomous reflexes enable animals to respond quickly to potential threats, prevent injury and mediate fight or flight responses. Intense acoustic stimuli with sudden onsets elicit a startle reflex while stimuli of similar intensity but with longer rise times only cause a cardiac defence response. In laboratory settings, habituation appears to affect all of these reflexes so that the response amplitude generally decreases with repeated exposure to the stimulus. The startle reflex has become a model system for the study of the neural basis of simple learning processes and emotional processing and is often used as a diagnostic tool in medical applications. However, previous studies did not allow animals to avoid the stimulus and the evolutionary function and long-term behavioural consequences of repeated startling remain speculative. In this study we investigate the follow-up behaviour associated with the startle reflex in wild-captured animals using an experimental setup that allows individuals to exhibit avoidance behaviour. Results We present evidence that repeated elicitation of the acoustic startle reflex leads to rapid and pronounced sensitisation of sustained spatial avoidance behaviour in grey seals (Halichoerus grypus. Animals developed rapid flight responses, left the exposure pool and showed clear signs of fear conditioning. Once sensitised, seals even avoided a known food source that was close to the sound source. In contrast, animals exposed to non-startling (long rise time stimuli of the same maximum sound pressure habituated and flight responses waned or were absent from the beginning. The startle threshold of grey seals expressed in units of sensation levels was comparable to thresholds reported for other mammals (93 dB. Conclusions Our results demonstrate that the acoustic startle reflex plays a crucial role in mediating flight responses and strongly influences the motivational state of an animal beyond a short
13. The nondestructive evaluation of high temperature conditioned concrete in conjunction with acoustic emission and x-ray computed tomography
Su, Yu-Min; Hou, Tsung-Chin; Lin, Li-Chiang; Chen, Gwan-Ying; Pan, Huang-Hsing
2016-04-01
Portland Cement Concrete plays a vital part of protecting structural rebars or steels when high-temperature fire incidents occur, that induces loss of evaporate water, dehydration of CH, and deconstruction of C-S-H. The objective of the study was to assess fire-damaged concrete in conjunction with nondestructive evaluation methods of acoustic emission, visual inspections, and X-ray computed tomography. The experimental program was to mix an Ordinary Portland Cement concrete firstly. Concrete cylinders with twenty-day moisture cure were treated in a furnace with 400 and 600°C for one hour. After temperature is cooled down, the concrete cylinders were brought to air or moisture re-curing for ten days. Due to the incident of the furnace, acoustic emission associated with splitting tensile strength test was not able to continue. Future efforts are planned to resume this unfinished task. However, two proposed tasks were executed and completed, namely visual inspections and voids analysis on segments obtained from X-ray CT facility. Results of visual inspections on cross-sectional and cylindrical length of specimens showed that both aggregates and cement pastes turned to pink or red at 600°C. More surface cracks were generated at 600°C than that at 400°C. On the other hand, voids analysis indicated that not many cracks were generated and voids were remedied at 400°C. However, a clear tendency was found that remedy by moisture curing may heal up to 2% voids of the concrete cylinder that was previously subject to 600°C of high temperature conditioning.
14. Indoor acoustic gain design
Concha-Abarca, Justo Andres
2002-11-01
The design of sound reinforcement systems includes many variables and usually some of these variables are discussed. There are criteria to optimize the performance of the sound reinforcement systems under indoor conditions. The equivalent acoustic distance, the necessary acoustic gain, and the potential acoustic gain are parameters which must be adjusted with respect to the loudspeaker array, electric power and directionality of loudspeakers, the room acoustics conditions, the distance and distribution of the audience, and the type of the original sources. The design and installation of front of the house and monitoring systems have individual criteria. This article is about this criteria and it proposes general considerations for the indoor acoustic gain design.
15. Acoustic and Perceptual Measures of SATB Choir Performances on Two Types of Portable Choral Riser Units in Three Singer-Spacing Conditions
Daugherty, James F.; Manternach, Jeremy N.; Brunkan, Melissa C.
2013-01-01
Under controlled conditions, we assessed acoustically (long-term average spectra) and perceptually (singer survey, listener survey) six performances of an soprano, alto, tenor, and bass (SATB) choir ("N" = 27) as it sang the same musical excerpt on two portable riser units (standard riser step height, taller riser step height) with…
16. The effects of bonding conditions on the propagation of acoustic waves along a cased borehole
LI Zhenglin; DU Guangsheng; WANG Yaojun
2001-01-01
Based on the wave equations in cylindrically layered structures and boundary conditions, the frequency equation for axisymmetric guided waves and the expression for sound fields in a cased borehole excited by a monopole or multipole source have been derived. The synthetic full waveforms excited by the monopole and dipole source are simulated using a real axis integration and FFT method. According to the axisymmetric guided wave modes, the synthetic full waveforms and the effects of the interface conditions on the sound field in a cased borehole have been analyzed and studied respectively. Numerical results indicate that it may be difficult to distinguish well bonded, poorly bonded or unbonded intermediate layer between the steel pipe and formation if only using a monopole source or dipole source. To properly estimate the case boundary conditions, a combination of monopole source logging with dipole source logging is suggested.
17. Modulation of the N170 with Classical Conditioning: The Use of Emotional Imagery and Acoustic Startle in Healthy and Depressed Participants.
Camfield, David A; Mills, Jessica; Kornfeld, Emma J; Croft, Rodney J
2016-01-01
Recent studies have suggested that classical conditioning may be capable of modulating early sensory processing in the human brain, and that there may be differences in the magnitude of the conditioned changes for individuals with major depressive disorder. The effect of conditioning on the N170 event-related potential was investigated using neutral faces as conditioned stimuli (CS+) and emotional imagery and acoustic startle as unconditioned stimuli (UCS). In the first experiment, electroencephalogram was recorded from 24 undergraduate students (M = 21.07 years, SD = 3.38 years) under the following conditions: (i) CS+/aversive imagery, (ii) CS+/aversive imagery and acoustic startle, (iii) CS+/acoustic startle, and (iv) CS+/pleasant imagery. The amplitude of the N170 was enhanced following conditioning with aversive imagery as well as acoustic startle. In the second experiment, 26 healthy control participants were tested (17 females and 9 males, age M = 25.97 years, SD = 9.42) together with 18 depressed participants (13 females and 5 males, age M = 23.26 years, SD = 4.01) and three conditions were used: CS+/aversive imagery, CS+/pleasant imagery, and CS-. N170 amplitude at P7 was increased for the CS+/aversive condition in comparison to CS- in the conditioning blocks versus baseline. No differences between depressed and healthy participants were found. Across both experiments, evaluative conditioning was absent. It was concluded that aversive UCS are capable of modulating early sensory processing of faces, although further research is also warranted in regards to positive UCS.
18. Weapon identification across varying acoustic conditions using an exemplar embedding approach
Khan, Saad; Divakaran, Ajay; Sawhney, Harpreet S.
2010-04-01
Gunshot recordings have the potential for both tactical detection and forensic evaluation particularly to ascertain information about the type of firearm and ammunition used. Perhaps the most significant challenge to such an analysis is the effect of recording conditions on the audio signature of recorded data. In this paper we present a first study of using an exemplar embedding approach to automatically detect and classify firearm type across different recording conditions. We demonstrate that a small number of exemplars can span the space of gunshot audio signatures and that this optimal set can be obtained using a wrapper function. By projecting a given gunshot to the subspace spanned by the exemplar set a distance measure/feature vector is obtained that enables comparisons across recording conditions. We also investigate the use of a hierarchy of gunshot classifications that assists in improving finer level classification by pruning out gunshot labeling that is inconsistent with its higher level type. The embedding based approach can thus be used both by itself and as a pruning stage for other search techniques. Our dataset includes 20 different gun types captured in a number of different conditions. This data acts as our original exemplar set. The dataset also includes 12 gun types each with multiple shots recorded in the same conditions as the exemplar set. This second set provides our training and testing sets. We show that we can reduce our exemplar space from 20 to only 4 uniquely different gunshots without significantly limiting the ability of our embedding approach to discriminate different gunshots in the training and testing sets. The basic hypothesis in the embedding approach is that the relationship between the set of exemplars and space of gunshots including the testing/training set would be robust to a change in recording conditions or the environment. That is to say the embedding distance between a particular gunshot and the exemplars would tend
19. Near-Field Acoustic Power Level Analysis of F31/A31 Open Rotor Model at Simulated Cruise Conditions, Technical Report II
Sree, Dave
2015-01-01
Near-field acoustic power level analysis of F31A31 open rotor model has been performed to determine its noise characteristics at simulated cruise flight conditions. The non-proprietary parts of the test data obtained from experiments in the 8x6 supersonic wind tunnel were provided by NASA-Glenn Research Center. The tone and broadband components of total noise have been separated from raw test data by using a new data analysis tool. Results in terms of sound pressure levels, acoustic power levels, and their variations with rotor speed, freestream Mach number, and input shaft power, with different blade-pitch setting angles at simulated cruise flight conditions, are presented and discussed. Empirical equations relating models acoustic power level and input shaft power have been developed. The near-field acoustic efficiency of the model at simulated cruise conditions is also determined. It is hoped that the results presented in this work will serve as a database for comparison and improvement of other open rotor blade designs and also for validating open rotor noise prediction codes.
20. [The effects of Mexidol on food conditioning and synaptic fine structure of hippocampal field CA1 in rats exposed to a single acoustic stimulation with ultrasonic components].
Alekseeva, T G; Loseva, E V; Mering, T A
2004-01-01
The effect of exposure of rats to a complex acoustic signal with ultrasonic components on line structure of synapses of the CA1 field of the hippocampus was studied during a course treatment (two weeks) with broad-spectrum antioxidant Mexidol. Under the same conditions, the time course of food conditioning by a conditioned tone stimulus and acquisition of trace conditioned reflex (time interval counting) were studied in the same rat group. Rats non-exposed to stress against the background of Mexidol and without Mexidol treatment served as control. Analysis of fine structure of the vesicle redistribution in CA1 synapses revealed a reduction of the efficacy of synaptic transmission a day after the exposure to the complex acoustic stimulus. We found a negative effect of the complex acoustic stimulus on conditioning by tone and acquisition of time-counting trace reflex by rats. This effect was shown to be normalized by the course Mexidol treatment. The results suggests the expediency of Mexidol application for prevention of cognitive disorders, which are frequent under stress-inducing conditions.
1. Correcting acoustic Doppler current profiler discharge measurement bias from moving-bed conditions without global positioning during the 2004 Glen Canyon Dam controlled flood on the Colorado River
Gartner, J.W.; Ganju, N.K.
2007-01-01
Discharge measurements were made by acoustic Doppler current profiler at two locations on the Colorado River during the 2004 controlled flood from Glen Canyon Dam, Arizona. Measurement hardware and software have constantly improved from the 1980s such that discharge measurements by acoustic profiling instruments are now routinely made over a wide range of hydrologic conditions. However, measurements made with instruments deployed from moving boats require reliable boat velocity data for accurate measurements of discharge. This is normally accomplished by using special acoustic bottom track pings that sense instrument motion over bottom. While this method is suitable for most conditions, high current flows that produce downstream bed sediment movement create a condition known as moving bed that will bias velocities and discharge to lower than actual values. When this situation exists, one solution is to determine boat velocity with satellite positioning information. Another solution is to use a lower frequency instrument. Discharge measurements made during the 2004 Glen Canyon controlled flood were subject to moving-bed conditions and frequent loss of bottom track. Due to site conditions and equipment availability, the measurements were conducted without benefit of external positioning information or lower frequency instruments. This paper documents and evaluates several techniques used to correct the resulting underestimated discharge measurements. One technique produces discharge values in good agreement with estimates from numerical model and measured hydrographs during the flood. ?? 2007, by the American Society of Limnology and Oceanography, Inc.
2. Ion temperature anisotropy effects on threshold conditions of a shear-modified current driven electrostatic ion-acoustic instability in the topside auroral ionosphere
Perron, P. J. G.; J.-M. A. Noël; Kabin, K.; St-Maurice, J.-P.
2013-01-01
Temperature anisotropies may be encountered in space plasmas when there is a preferred direction, for instance, a strong magnetic or electric field. In this paper, we study how ion temperature anisotropy can affect the threshold conditions of a shear-modified current driven electrostatic ion-acoustic (CDEIA) instability. In particular, this communication focuses on instabilities in the context of topside auroral F-region situations and in the limit where finite Larmor radius...
3. Shared Frailty Model for Left-Truncated Multivariate Survival Data
Jensen, Henrik; Brookmeyer, Ron; Aaby, Peter;
multivariate survival data, left truncation, multiplicative hazard model, shared gamma frailty, conditional model, piecewise exponential model, childhood survival......multivariate survival data, left truncation, multiplicative hazard model, shared gamma frailty, conditional model, piecewise exponential model, childhood survival...
4. Condiciones acústicas de las aulas universitarias en una Universidad pública en Bogotá Classroom acoustics conditions at public University in Bogotá
2009-09-01
5. Multivariate supOU processes
Barndorff-Nielsen, Ole Eiler; Stelzer, Robert
2011-01-01
Univariate superpositions of Ornstein–Uhlenbeck-type processes (OU), called supOU processes, provide a class of continuous time processes capable of exhibiting long memory behavior. This paper introduces multivariate supOU processes and gives conditions for their existence and finiteness of momen...
6. Interactions in an acoustic world
Simaciu, Ion; Borsos, Zoltan; Bradac, Mariana
2016-01-01
The present paper aims to complete an earlier paper where the acoustic world was introduced. This is accomplished by analyzing the interactions which occur between the inhomogeneities of the acoustic medium, which are induced by the acoustic vibrations traveling in the medium. When a wave packet travels in a medium, the medium becomes inhomogeneous. The spherical wave packet behaves like an acoustic spherical lens for the acoustic plane waves. According to the principle of causality, there is an interaction between the wave and plane wave packet. In specific conditions the wave packet behaves as an acoustic black hole.
7. Multivariate analysis with LISREL
Jöreskog, Karl G; Y Wallentin, Fan
2016-01-01
This book traces the theory and methodology of multivariate statistical analysis and shows how it can be conducted in practice using the LISREL computer program. It presents not only the typical uses of LISREL, such as confirmatory factor analysis and structural equation models, but also several other multivariate analysis topics, including regression (univariate, multivariate, censored, logistic, and probit), generalized linear models, multilevel analysis, and principal component analysis. It provides numerous examples from several disciplines and discusses and interprets the results, illustrated with sections of output from the LISREL program, in the context of the example. The book is intended for masters and PhD students and researchers in the social, behavioral, economic and many other sciences who require a basic understanding of multivariate statistical theory and methods for their analysis of multivariate data. It can also be used as a textbook on various topics of multivariate statistical analysis.
8. Prediction of acoustic radiation from axisymmetric surfaces with arbitrary boundary conditions using the boundary element method on a distributed computing system.
Wright, Louise; Robinson, Stephen P; Humphrey, Victor F
2009-03-01
This paper presents a computational technique using the boundary element method for prediction of radiated acoustic waves from axisymmetric surfaces with nonaxisymmetric boundary conditions. The aim is to predict the far-field behavior of underwater acoustic transducers based on their measured behavior in the near-field. The technique is valid for all wavenumbers and uses a volume integral method to calculate the singular integrals required by the boundary element formulation. The technique has been implemented on a distributed computing system to take advantage of its parallel nature, which has led to significant reductions in the time required to generate results. Measurement data generated by a pair of free-flooding underwater acoustic transducers encapsulated in a polyurethane polymer have been used to validate the technique against experiment. The dimensions of the outer surface of the transducers (including the polymer coating) were an outer diameter of 98 mm with an 18 mm wall thickness and a length of 92 mm. The transducers were mounted coaxially, giving an overall length of 185 mm. The cylinders had resonance frequencies at 13.9 and 27.5 kHz, and the data were gathered at these frequencies.
9. Ion temperature anisotropy effects on threshold conditions of a shear-modified current driven electrostatic ion-acoustic instability in the topside auroral ionosphere
P. J. G. Perron
2013-03-01
Full Text Available Temperature anisotropies may be encountered in space plasmas when there is a preferred direction, for instance, a strong magnetic or electric field. In this paper, we study how ion temperature anisotropy can affect the threshold conditions of a shear-modified current driven electrostatic ion-acoustic (CDEIA instability. In particular, this communication focuses on instabilities in the context of topside auroral F-region situations and in the limit where finite Larmor radius corrections are small. We derived a new fluid-like expression for the critical drift which depends explicitly on ion anisotropy. More importantly, for ion to electron temperature ratios typical of F-region, solutions of the kinetic dispersion relation show that ion temperature anisotropy may significantly lower the drift threshold required for instability. In some cases, a perpendicular to parallel ion temperature ratio of 2 and may reduce the relative drift required for the onset of instability by a factor of approximately 30, assuming the ion-acoustic speed of the medium remains constant. Therefore, the ion temperature anisotropy should be considered in future studies of ion-acoustic waves and instabilities in the high-latitude ionospheric F-region.
10. Acoustic Performance of Novel Fan Noise Reduction Technologies for a High Bypass Model Turbofan at Simulated Flights Conditions
Elliott, David M.; Woodward, Richard P.; Podboy, Gary G.
2010-01-01
Two novel fan noise reduction technologies, over the rotor acoustic treatment and soft stator vane technologies, were tested in an ultra-high bypass ratio turbofan model in the NASA Glenn Research Center s 9- by 15-Foot Low-Speed Wind Tunnel. The performance of these technologies was compared to that of the baseline fan configuration, which did not have these technologies. Sideline acoustic data and hot film flow data were acquired and are used to determine the effectiveness of the various treatments. The material used for the over the rotor treatment was foam metal and two different types were used. The soft stator vanes had several internal cavities tuned to target certain frequencies. In order to accommodate the cavities it was necessary to use a cut-on stator to demonstrate the soft vane concept.
11. Multivariate irregular sampling theorem
2009-01-01
In this paper,we prove a Marcinkiewicz-Zygmund type inequality for multivariate entire functions of exponential type with non-equidistant spaced sampling points. And from this result,we establish a multivariate irregular Whittaker-Kotelnikov-Shannon type sampling theorem.
12. Multivariate GARCH models
Silvennoinen, Annastiina; Teräsvirta, Timo
This article contains a review of multivariate GARCH models. Most common GARCH models are presented and their properties considered. This also includes nonparametric and semiparametric models. Existing specification and misspecification tests are discussed. Finally, there is an empirical example...... in which several multivariate GARCH models are fitted to the same data set and the results compared....
13. Switching Between Multivariable Controllers
Niemann, H.; Stoustrup, Jakob; Abrahamsen, R.B.
2004-01-01
A concept for implementation of multivariable controllers is presented in this paper. The concept is based on the Youla-Jabr-Bongiorno-Kucera (YJBK) parameterization of all stabilizing controllers. By using this architecture for implementation of multivariable controllers, it is shown how...
14. Switching Between Multivariable Controllers
Niemann, Hans Henrik; Stoustrup, Jakob; Abrahamsen, Rune
2004-01-01
it is possible to smoothly switch between multivariable controllers with guaranteed closed-loop stability. This includes also the case where one or more controllers are unstable. The concept for smooth online changes of multivariable controllers based on the YJBK architecture can also handle the start up...
15. Multivariate irregular sampling theorem
CHEN GuangGui; FANG GenSun
2009-01-01
In this paper, we prove a Marcinkiewicz-Zygmund type inequality for multivariate entire functions of exponential type with non-equidistant spaced sampling points. And from this result, we establish a multivariate irregular Whittaker-Kotelnikov-Shannon type sampling theorem.
16. Methods of Multivariate Analysis
Rencher, Alvin C
2012-01-01
Praise for the Second Edition "This book is a systematic, well-written, well-organized text on multivariate analysis packed with intuition and insight . . . There is much practical wisdom in this book that is hard to find elsewhere."-IIE Transactions Filled with new and timely content, Methods of Multivariate Analysis, Third Edition provides examples and exercises based on more than sixty real data sets from a wide variety of scientific fields. It takes a "methods" approach to the subject, placing an emphasis on how students and practitioners can employ multivariate analysis in real-life sit
17. Ultrasonic condition monitoring of composite structures using a low-profile acoustic source and an embedded optical fiber sensor
Pierce, S. Gareth; Staszewski, Wieslaw J.; Gachagan, Anthony; James, I. R.; Philip, Wayne R.; Worden, Keith; Culshaw, Brian; McNab, Alistair; Tomlinson, Geoffrey R.; Hayward, Gordon
1997-06-01
The purpose of this paper is to provide a concise introduction to the developments and recent findings of a BRITE-EURAM program of work (BRE2.CT94-0990 , structurally integrated system for the comprehensive evaluation of composites). The aim of the program has been to develop an acoustic/ultrasonic based structural monitoring system for composite structures using material compatible sensors. Since plate-like structures have been investigated, it has been a requirement to utilize the propagation of ultrasonic Lamb waves through the sample materials. Preliminary investigations utilized conventional piezo-electric sources coupled to the sample via perspex wedges. The Lamb waves generated by these sources were monitored using either a fully embedded or surface mounted optical fiber sensors. The system was tested with a variety of different carbon and glass fiber reinforced panels, and the interaction of the lamb waves with different defects in these materials was monitored. Conventional signal processing allowed the location of defects such as impact damage sites, delaminations and holes. Subsequent investigations have endeavored to refine the system. This paper reports the development of advanced wavelet based signal processing techniques to enhance defect visibility, the optical connectorization of composite panels, and the development of flexible low profile acoustic sources for efficient Lamb wave generation.
18. Communication Acoustics
Blauert, Jens
Communication Acoustics deals with the fundamentals of those areas of acoustics which are related to modern communication technologies. Due to the advent of digital signal processing and recording in acoustics, these areas have enjoyed an enormous upswing during the last 4 decades. The book...... the book a source of valuable information for those who want to improve or refresh their knowledge in the field of communication acoustics - and to work their way deeper into it. Due to its interdisciplinary character Communication Acoustics is bound to attract readers from many different areas, such as......: acoustics, cognitive science, speech science, and communication technology....
19. Multivariate Time Series Search
National Aeronautics and Space Administration — Multivariate Time-Series (MTS) are ubiquitous, and are generated in areas as disparate as sensor recordings in aerospace systems, music and video streams, medical...
20. Nicotine withdrawal disrupts both foreground and background contextual fear conditioning but not pre-pulse inhibition of the acoustic startle response in C57BL/6 mice.
André, Jessica M; Gulick, Danielle; Portugal, George S; Gould, Thomas J
2008-07-19
Nicotine withdrawal is associated with multiple symptoms such as anxiety, increased appetite, and disrupted cognition in humans. Although animal models have provided insights into the somatic and affective symptoms of nicotine withdrawal, less research has focused on the effects of nicotine withdrawal on cognition. Therefore, in this study, C57BL/6J mice were used to test the effects of withdrawal from chronic nicotine on foreground and background contextual fear conditioning, which present the context as a primary or secondary stimulus, respectively. Mice withdrawn from 12 days of chronic nicotine (6.3mg/kg/day) or saline were trained and tested in either foreground or background contextual fear conditioning; nicotine withdrawal-associated deficits in contextual fear conditioning were observed in both conditions. Mice were also tested for the effects of withdrawal on pre-pulse inhibition of the acoustic startle reflex (PPI), a measure of sensory gating, and on the acoustic startle reflex. Mice withdrawn from 12 days of chronic nicotine (6.3 or 12.6 mg/kg/day) or saline underwent one 30-min PPI and startle session; no effect of withdrawal from chronic nicotine on PPI or startle was observed for either dose at 24h after nicotine removal. Therefore, mice were tested at different time points following withdrawal from 12.6 mg/kg/day chronic nicotine (8, 24, and 48 h after nicotine removal). No effect of withdrawal from chronic nicotine was observed at any time point for PPI. Overall, these results demonstrate that nicotine withdrawal disrupts two methods of contextual learning but not sensory gating in C57BL/6J mice.
1. Assessment of the application of acoustic emission technology for monitoring the presence of sand under multiphase flow condition
El-Alej, M., E-mail: m.elalej@cranfield.ac.uk; Mba, D., E-mail: m.elalej@cranfield.ac.uk; Yeung, H., E-mail: m.elalej@cranfield.ac.uk [School of Engineering, Cranfield University, Cranfield, Bedfordshire, MK43 OAL (United Kingdom)
2014-04-11
The monitoring of multiphase flow is an established process that has spanned several decades. This paper demonstrates the use of acoustic emission (AE) technology to investigate sand transport characteristic in three-phase (air-water-sand) flow in a horizontal pipe where the superficial gas velocity (VSG) had a range of between 0.2 ms{sup −1} to 2.0 ms{sup −1} and superficial liquid velocity (VSL) had a range of between 0.2 ms{sup −1} to 1.0 ms{sup −1}. The experimental findings clearly show a correlation exists between AE energy levels, sand concentration, superficial gas velocity (VSG) and superficial liquid velocity (VSL)
2. Oil condition monitoring of gears onboard ships using a regression approach for multivariate T2 control charts
Henneberg, Morten; Jørgensen, Bent; Eriksen, René Lynge
2016-01-01
In this paper, we present an oil condition and wear debris evaluation method for ship thruster gears using T2 statistics to form control charts from a multi-sensor platform. The proposed method takes into account the different ambient conditions by multiple linear regression on the mean value...... as substitution from the normal empirical mean value. This regression approach accounts for the bias imposed on the empirical mean value due to different geographical and seasonal differences on the multi-sensor inputs. Data from a gearbox are used to evaluate the length of the run-in period in order to ensure...... only quasi-stationary data are included in phase I of the T2 statistics. Data from two thruster gears onboard two different ships are presented and analyzed, and the selection of the phase I data size is discussed. A graphic overview for quick localization of T2 signaling is also demonstrated using...
3. Acoustic telemetry
National Oceanic and Atmospheric Administration, Department of Commerce — To determine movements of green turtles in the nearshore foraging areas, we deployed acoustic tags and determined their movements through active and passive acoustic...
4. Acoustic characteristics of the water of the Bay of Bengal
Murty, T.V.R.; Somayajulu, Y.K.; Chodankar, P.V.; Murty, C.S.
Acoustic eigen rays (rays connecting the source and receiver) have been indentified and their turning depth, path length, travel time etc. evaluated. Acoustic intensity loss due to mean environmental conditions, vergence along acoustic rays...
5. Protein phosphorylation stoichiometry by simultaneous ICP-QMS determination of phosphorus and sulfur oxide ions: a multivariate optimization of plasma operating conditions.
Ciavardelli, Domenico; Sacchetta, Paolo; Federici, Giorgio; Di Ilio, Carmine; Urbani, Andrea
2010-02-15
Molecular mass spectrometry (MS) analysis of protein phosphorylation is partially limited by the molecular specie specificity of the analytical responses that might impair both qualitative and quantitative performances. Elemental MS, such as inductively coupled plasma mass spectrometry (ICP-MS) can overcome these drawbacks; in fact, analytical performance is theoretically independent of the molecular structure of a target analyte naturally containing the elements of interest. Nevertheless, isobaric interferences derived from sample matrix and laboratory environment can hinder the quantitative determination of both phosphorus (P) and sulfur (S) as (31)P(+) and (32)S(+) by inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) under standard plasma conditions. These interferences may be overcome by quantifying P and S as oxide ions (31)P(16)O(+) and (32)S(16)O(+), respectively. In this study, we present a systematic investigation on the effect of plasma instrumental conditions on the oxide ion responses by a design of experiment approach for the simultaneous ICP-QMS determination of P and S ((31)P(16)O(+) and (32)S(16)O(+), respectively) in protein samples without the use of dynamic reaction, collision reaction cells or pre-addition of oxygen as reactant gas in the torch. The proposed method was evaluated in terms of limit of detection, limit of quantification, linearity, repeatability, and trueness. Moreover, detection and quantification capabilities of the optimized method were compared to the standard plasma mode for determination of (31)P(+) and (34)S(+). Spectral and non-spectral interferences affecting the quantification of (31)P(+), (31)P(16)O(+) and (32)S(16)O(+) were also studied. The suitability of inorganic elemental standards for P and S quantification in proteins was assessed. The method was applied to quantify the phosphorylation stoichiometry of commercially available caseins (bovine beta-casein, native and dephosphorylated alpha-casein) and
6. Multivariate Birkhoff interpolation
Lorentz, Rudolph A
1992-01-01
The subject of this book is Lagrange, Hermite and Birkhoff (lacunary Hermite) interpolation by multivariate algebraic polynomials. It unifies and extends a new algorithmic approach to this subject which was introduced and developed by G.G. Lorentz and the author. One particularly interesting feature of this algorithmic approach is that it obviates the necessity of finding a formula for the Vandermonde determinant of a multivariate interpolation in order to determine its regularity (which formulas are practically unknown anyways) by determining the regularity through simple geometric manipulations in the Euclidean space. Although interpolation is a classical problem, it is surprising how little is known about its basic properties in the multivariate case. The book therefore starts by exploring its fundamental properties and its limitations. The main part of the book is devoted to a complete and detailed elaboration of the new technique. A chapter with an extensive selection of finite elements follows as well a...
7. Applied multivariate statistical analysis
Härdle, Wolfgang Karl
2015-01-01
Focusing on high-dimensional applications, this 4th edition presents the tools and concepts used in multivariate data analysis in a style that is also accessible for non-mathematicians and practitioners. It surveys the basic principles and emphasizes both exploratory and inferential statistics; a new chapter on Variable Selection (Lasso, SCAD and Elastic Net) has also been added. All chapters include practical exercises that highlight applications in different multivariate data analysis fields: in quantitative financial studies, where the joint dynamics of assets are observed; in medicine, where recorded observations of subjects in different locations form the basis for reliable diagnoses and medication; and in quantitative marketing, where consumers’ preferences are collected in order to construct models of consumer behavior. All of these examples involve high to ultra-high dimensions and represent a number of major fields in big data analysis. The fourth edition of this book on Applied Multivariate ...
8. Multivariate bubbles and antibubbles
Fry, John
2014-08-01
In this paper we develop models for multivariate financial bubbles and antibubbles based on statistical physics. In particular, we extend a rich set of univariate models to higher dimensions. Changes in market regime can be explicitly shown to represent a phase transition from random to deterministic behaviour in prices. Moreover, our multivariate models are able to capture some of the contagious effects that occur during such episodes. We are able to show that declining lending quality helped fuel a bubble in the US stock market prior to 2008. Further, our approach offers interesting insights into the spatial development of UK house prices.
9. Behavioral determination of stimulus pair discrimination of auditory acoustic and electrical stimuli using a classical conditioning and heart-rate approach.
Morgan, Simeon J; Paolini, Antonio G
2012-06-06
Acute animal preparations have been used in research prospectively investigating electrode designs and stimulation techniques for integration into neural auditory prostheses, such as auditory brainstem implants and auditory midbrain implants. While acute experiments can give initial insight to the effectiveness of the implant, testing the chronically implanted and awake animals provides the advantage of examining the psychophysical properties of the sensations induced using implanted devices. Several techniques such as reward-based operant conditioning, conditioned avoidance, or classical fear conditioning have been used to provide behavioral confirmation of detection of a relevant stimulus attribute. Selection of a technique involves balancing aspects including time efficiency (often poor in reward-based approaches), the ability to test a plurality of stimulus attributes simultaneously (limited in conditioned avoidance), and measure reliability of repeated stimuli (a potential constraint when physiological measures are employed). Here, a classical fear conditioning behavioral method is presented which may be used to simultaneously test both detection of a stimulus, and discrimination between two stimuli. Heart-rate is used as a measure of fear response, which reduces or eliminates the requirement for time-consuming video coding for freeze behaviour or other such measures (although such measures could be included to provide convergent evidence). Animals were conditioned using these techniques in three 2-hour conditioning sessions, each providing 48 stimulus trials. Subsequent 48-trial testing sessions were then used to test for detection of each stimulus in presented pairs, and test discrimination between the member stimuli of each pair. This behavioral method is presented in the context of its utilisation in auditory prosthetic research. The implantation of electrocardiogram telemetry devices is shown. Subsequent implantation of brain electrodes into the Cochlear
10. Vis-NIR hyperspectral imaging and multivariate analysis for prediction of the moisture content and hardness of Pistachio kernels roasted in different conditions
2015-09-01
Full Text Available Introduction: Pistachio nut is one of the most delicious and nutritious nuts in the world and it is being used as a salted and roasted product or as an ingredient in snacks, ice cream, desserts, etc. (Maghsudi, 2010; Kashaninejad et al. 2006. Roasting is one of the most important food processes which provides useful attributes to the product. One of the objectives of nut roasting is to alter and significantly enhance the flavor, texture, color and appearance of the product (Ozdemir, 2001. In recent years, spectral imaging techniques (i.e. hyperspectral and multispectral imaging have emerged as powerful tools for safequality inspection of various agricultural commodities (Gowen et al., 2007. The objectives of this study were to apply reflectance hyperspectral imaging for non-destructive determination of moisture content and hardness of pistachio kernels roasted in different conditions. Materials and methods: Dried O’hadi pistachio nuts were supplied from a local market in Mashhad. Pistachio nuts were soaked in 5L of 20% salt solution for 20min (Goktas Seyhan, 2003. For roasting process, three temperatures (90, 120 and 150°C, three times (20, 35 and 50 min and three air velocities (0.5, 1.5 and 2.5 m s-1 were applied. The moisture content of pistachio kernels was measured in triplicate using oven drying (3 gr samples at 105 °C for 12 hours. Uniaxial compression test by a 35mm diameter plastic cylinder, was made on the pistachio kernels, which were mounted on a platform. Samples were compressed at a depth of 2mm and speed of 30 mm min-1. A hyperspectral imaging system in the Vis-NIR range (400-1000 nm was employed. The spectral pre-processing techniques: first derivative and second derivative, median filter, Savitzkye-Golay, wavelet, multiplicative scatter correction (MSC and standard normal variate transformation (SNV were used. To make models at PLSR and ANN methods, ParLeS software and Matlab R2009a were used, respectively. The coefficient
11. Multivariate data analysis
Interest in statistical methodology is increasing so rapidly in the astronomical community that accessible introductory material in this area is long overdue. This book fills the gap by providing a presentation of the most useful techniques in multivariate statistics. A wide-ranging annotated set...
12. Multivariate realised kernels
Barndorff-Nielsen, Ole Eiler; Hansen, Peter Reinhard; Lunde, Asger
2011-01-01
We propose a multivariate realised kernel to estimate the ex-post covariation of log-prices. We show this new consistent estimator is guaranteed to be positive semi-definite and is robust to measurement error of certain types and can also handle non-synchronous trading. It is the first estimator...
13. Orthogonality Relations for Multivariate Krawtchouk Polynomials
Hiroshi Mizukawa
2011-02-01
Full Text Available The orthogonality relations of multivariate Krawtchouk polynomials are discussed. In case of two variables, the necessary and sufficient conditions of orthogonality is given by Grünbaum and Rahman in [SIGMA 6 (2010, 090, 12 pages]. In this study, a simple proof of the necessary and sufficient condition of orthogonality is given for a general case.
14. Acoustical Imaging
Litniewski, Jerzy; Kujawska, Tamara; 31st International Symposium on Acoustical Imaging
2012-01-01
The International Symposium on Acoustical Imaging is a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. This interdisciplinary Symposium has been taking place continuously since 1968. In the course of the years the proceedings volumes in the Acoustical Imaging Series have become a reference for cutting-edge research in the field. In 2011 the 31st International Symposium on Acoustical Imaging was held in Warsaw, Poland, April 10-13. Offering both a broad perspective on the state-of-the-art as well as in-depth research contributions by the specialists in the field, this Volume 31 in the Series contains an excellent collection of papers in six major categories: Biological and Medical Imaging Physics and Mathematics of Acoustical Imaging Acoustic Microscopy Transducers and Arrays Nondestructive Evaluation and Industrial Applications Underwater Imaging
15. Acoustic textiles
Nayak, Rajkishore
2016-01-01
This book highlights the manufacturing and applications of acoustic textiles in various industries. It also includes examples from different industries in which acoustic textiles can be used to absorb noise and help reduce the impact of noise at the workplace. Given the importance of noise reduction in the working environment in several industries, the book offers a valuable guide for companies, educators and researchers involved with acoustic materials.
16. Acoustic biosensors
Fogel, Ronen; Limson, Janice; Seshia, Ashwin A.
2016-01-01
Resonant and acoustic wave devices have been researched for several decades for application in the gravimetric sensing of a variety of biological and chemical analytes. These devices operate by coupling the measurand (e.g. analyte adsorption) as a modulation in the physical properties of the acoustic wave (e.g. resonant frequency, acoustic velocity, dissipation) that can then be correlated with the amount of adsorbed analyte. These devices can also be miniaturized with advantages in terms of ...
17. Acoustic telemetry.
Drumheller, Douglas Schaeffer; Kuszmaul, Scott S.
2003-08-01
Broadcasting messages through the earth is a daunting task. Indeed, broadcasting a normal telephone conversion through the earth by wireless means is impossible with todays technology. Most of us don't care, but some do. Industries that drill into the earth need wireless communication to broadcast navigation parameters. This allows them to steer their drill bits. They also need information about the natural formation that they are drilling. Measurements of parameters such as pressure, temperature, and gamma radiation levels can tell them if they have found a valuable resource such as a geothermal reservoir or a stratum bearing natural gas. Wireless communication methods are available to the drilling industry. Information is broadcast via either pressure waves in the drilling fluid or electromagnetic waves in the earth and well tubing. Data transmission can only travel one way at rates around a few baud. Given that normal Internet telephone modems operate near 20,000 baud, these data rates are truly very slow. Moreover, communication is often interrupted or permanently blocked by drilling conditions or natural formation properties. Here we describe a tool that communicates with stress waves traveling through the steel drill pipe and production tubing in the well. It's based on an old idea called Acoustic Telemetry. But what we present here is more than an idea. This tool exists, it's drilled several wells, and it works. Currently, it's the first and only acoustic telemetry tool that can withstand the drilling environment. It broadcasts one way over a limited range at much faster rates than existing methods, but we also know how build a system that can communicate both up and down wells of indefinite length.
18. Multivariate calculus and geometry
Dineen, Seán
2014-01-01
Multivariate calculus can be understood best by combining geometric insight, intuitive arguments, detailed explanations and mathematical reasoning. This textbook has successfully followed this programme. It additionally provides a solid description of the basic concepts, via familiar examples, which are then tested in technically demanding situations. In this new edition the introductory chapter and two of the chapters on the geometry of surfaces have been revised. Some exercises have been replaced and others provided with expanded solutions. Familiarity with partial derivatives and a course in linear algebra are essential prerequisites for readers of this book. Multivariate Calculus and Geometry is aimed primarily at higher level undergraduates in the mathematical sciences. The inclusion of many practical examples involving problems of several variables will appeal to mathematics, science and engineering students.
19. Multivariate wavelet frames
2016-01-01
This book presents a systematic study of multivariate wavelet frames with matrix dilation, in particular, orthogonal and bi-orthogonal bases, which are a special case of frames. Further, it provides algorithmic methods for the construction of dual and tight wavelet frames with a desirable approximation order, namely compactly supported wavelet frames, which are commonly required by engineers. It particularly focuses on methods of constructing them. Wavelet bases and frames are actively used in numerous applications such as audio and graphic signal processing, compression and transmission of information. They are especially useful in image recovery from incomplete observed data due to the redundancy of frame systems. The construction of multivariate wavelet frames, especially bases, with desirable properties remains a challenging problem as although a general scheme of construction is well known, its practical implementation in the multidimensional setting is difficult. Another important feature of wavelet is ...
20. Transient multivariable sensor evaluation
Vilim, Richard B.; Heifetz, Alexander
2017-02-21
A method and system for performing transient multivariable sensor evaluation. The method and system includes a computer system for identifying a model form, providing training measurement data, generating a basis vector, monitoring system data from sensor, loading the system data in a non-transient memory, performing an estimation to provide desired data and comparing the system data to the desired data and outputting an alarm for a defective sensor.
1. Multivariate Quantitative Chemical Analysis
Kinchen, David G.; Capezza, Mary
1995-01-01
Technique of multivariate quantitative chemical analysis devised for use in determining relative proportions of two components mixed and sprayed together onto object to form thermally insulating foam. Potentially adaptable to other materials, especially in process-monitoring applications in which necessary to know and control critical properties of products via quantitative chemical analyses of products. In addition to chemical composition, also used to determine such physical properties as densities and strengths.
2. Acoustics reveals the presence of a macrozooplankton biocline in the Bay of Biscay in response to hydrological conditions and predator-prey relationships.
Lezama-Ochoa, Ainhoa
2014-02-04
Bifrequency acoustic data, hydrological measurements and satellite data were used to study the vertical distribution of macrozooplankton in the Bay of Biscay in relation to the hydrological conditions and fish distribution during spring 2009. The most noticeable result was the observation of a \\'biocline\\' during the day i.e., the interface where zooplankton biomass changes more rapidly with depth than it does in the layers above or below. The biocline separated the surface layer, almost devoid of macrozooplankton, from the macrozooplankton-rich deeper layers. It is a specific vertical feature which ties in with the classic diel vertical migration pattern. Spatiotemporal correlations between macrozooplankton and environmental variables (photic depth, thermohaline vertical structure, stratification index and chlorophyll-a) indicate that no single factor explains the macrozooplankton vertical distribution. Rather a set of factors, the respective influence of which varies from region to region depending on the habitat characteristics and the progress of the spring stratification, jointly influence the distribution. In this context, the macrozooplankton biocline is potentially a biophysical response to the search for a particular depth range where light attenuation, thermohaline vertical structure and stratification conditions together provide a suitable alternative to the need for expending energy in reaching deeper water without the risk of being eaten.
3. Multivariate supOU processes
Barndorff-Nielsen, Ole Eiler; Stelzer, Robert
Univariate superpositions of Ornstein-Uhlenbeck (OU) type processes, called supOU processes, provide a class of continuous time processes capable of exhibiting long memory behaviour. This paper introduces multivariate supOU processes and gives conditions for their existence and finiteness...... of moments. Moreover, the second order moment structure is explicitly calculated, and examples exhibit the possibility of long range dependence. Our supOU processes are defined via homogeneous and factorisable Lévy bases. We show that the behaviour of supOU processes is particularly nice when the mean...... reversion parameter is restricted to normal matrices and especially to strictly negative definite ones.For finite variation Lévy bases we are able to give conditions for supOU processes to have locally bounded càdlàg paths of finite variation and to show an analogue of the stochastic differential equation...
4. Modelling of acoustic transmission through perforated layer
Lukeš V.
2007-10-01
Full Text Available The paper deals with modeling the acoustic transmission through a perforated interface plane separating two halfspaces occupied by the acoustic medium. We considered the two-scale homogenization limit of the standard acoustic problem imposed in the layer with the perforated periodic structure embedded inside. The homogenized transmission conditions govern the interface discontinuity of the acoustic pressure associated with the two halfspaces and the magnitude of the fictitious transversal acoustic velocity. By numerical examples we illustrate this novel approach of modeling the acoustic impedance of perforated interfaces.
5. Acoustic Ground-Impedance Meter
Zuckerwar, A. J.
1983-01-01
Helmoltz resonator used in compact, portable meter measures acoustic impedance of ground or other surfaces. Earth's surface is subject of increasing acoustical investigations because of its importance in aircraft noise prediction and measurment. Meter offers several advantages. Is compact and portable and set up at any test site, irrespective of landscape features, weather or other environmental condition.
6. Factors Influencing Hearing Preservation in Acoustic Tumor Surgery
Rastogi, Pawan; Cacace, Anthony T.; Lovely, Thomas J.
1995-01-01
In patients who underwent neurosurgery for excision of acoustic tumors, we used correlation and multivariate logistic regression analysis to study relationships among nine variables thought to have value in predicting hearing preservation. These variables included auditory perceptual, auditory neurophysiologic, and imaging-related characteristics of acoustic tumor dimensions. The univariate correlations showed two general trends. The first trend demonstrated relationships among imaging-relate...
7. Multivariate respiratory motion prediction
Dürichen, R.; Wissel, T.; Ernst, F.; Schlaefer, A.; Schweikard, A.
2014-10-01
In extracranial robotic radiotherapy, tumour motion is compensated by tracking external and internal surrogates. To compensate system specific time delays, time series prediction of the external optical surrogates is used. We investigate whether the prediction accuracy can be increased by expanding the current clinical setup by an accelerometer, a strain belt and a flow sensor. Four previously published prediction algorithms are adapted to multivariate inputs—normalized least mean squares (nLMS), wavelet-based least mean squares (wLMS), support vector regression (SVR) and relevance vector machines (RVM)—and evaluated for three different prediction horizons. The measurement involves 18 subjects and consists of two phases, focusing on long term trends (M1) and breathing artefacts (M2). To select the most relevant and least redundant sensors, a sequential forward selection (SFS) method is proposed. Using a multivariate setting, the results show that the clinically used nLMS algorithm is susceptible to large outliers. In the case of irregular breathing (M2), the mean root mean square error (RMSE) of a univariate nLMS algorithm is 0.66 mm and can be decreased to 0.46 mm by a multivariate RVM model (best algorithm on average). To investigate the full potential of this approach, the optimal sensor combination was also estimated on the complete test set. The results indicate that a further decrease in RMSE is possible for RVM (to 0.42 mm). This motivates further research about sensor selection methods. Besides the optical surrogates, the sensors most frequently selected by the algorithms are the accelerometer and the strain belt. These sensors could be easily integrated in the current clinical setup and would allow a more precise motion compensation.
8. Numerical Absorbing Boundary Conditions Based on a Damped Wave Equation for Pseudospectral Time-Domain Acoustic Simulations
Reche-López, Pedro; Hernández, Erwin
2014-01-01
In the context of wave-like phenomena, Fourier pseudospectral time-domain (PSTD) algorithms are some of the most efficient time-domain numerical methods for engineering applications. One important drawback of these methods is the so-called Gibbs phenomenon. This error can be avoided by using absorbing boundary conditions (ABC) at the end of the simulations. However, there is an important lack of ABC using a PSTD methods on a wave equation. In this paper, we present an ABC model based on a PSTD damped wave equation with an absorption parameter that depends on the position. Some examples of optimum variation profiles are studied analytically and numerically. Finally, the results of this model are also compared to another ABC model based on an hybrid formulation of the scalar perfectly matched layer. PMID:24737966
9. Multivariate Statistical Process Control
Kulahci, Murat
2013-01-01
As sensor and computer technology continues to improve, it becomes a normal occurrence that we confront with high dimensional data sets. As in many areas of industrial statistics, this brings forth various challenges in statistical process control (SPC) and monitoring for which the aim...... is to identify “out-of-control” state of a process using control charts in order to reduce the excessive variation caused by so-called assignable causes. In practice, the most common method of monitoring multivariate data is through a statistic akin to the Hotelling’s T2. For high dimensional data with excessive...
10. Far-Field Acoustic Power Level and Performance Analyses of F31/A31 Open Rotor Model at Simulated Scaled Takeoff, Nominal Takeoff, and Approach Conditions: Technical Report I
Sree, Dave
2015-01-01
Far-field acoustic power level and performance analyses of open rotor model F31/A31 have been performed to determine its noise characteristics at simulated scaled takeoff, nominal takeoff, and approach flight conditions. The nonproprietary parts of the data obtained from experiments in 9- by 15-Foot Low-Speed Wind Tunnel (9?15 LSWT) tests were provided by NASA Glenn Research Center to perform the analyses. The tone and broadband noise components have been separated from raw test data by using a new data analysis tool. Results in terms of sound pressure levels, acoustic power levels, and their variations with rotor speed, angle of attack, thrust, and input shaft power have been presented and discussed. The effect of an upstream pylon on the noise levels of the model has been addressed. Empirical equations relating model's acoustic power level, thrust, and input shaft power have been developed. The far-field acoustic efficiency of the model is also determined for various simulated flight conditions. It is intended that the results presented in this work will serve as a database for comparison and improvement of other open rotor blade designs and also for validating open rotor noise prediction codes.
11. Asymptotic Theory for Extended Asymmetric Multivariate GARCH Processes
M. Asai (Manabu); M.J. McAleer (Michael)
2016-01-01
textabstractThe paper considers various extended asymmetric multivariate conditional volatility models, and derives appropriate regularity conditions and associated asymptotic theory. This enables checking of internal consistency and allows valid statistical inferences to be drawn based on empirical
12. Speed of sound measurements and mixing characterization of underexpanded fuel jets with supercritical reservoir condition using laser-induced thermal acoustics
Baab, S.; Förster, F. J.; Lamanna, G.; Weigand, B.
2016-11-01
The four-wave mixing technique laser-induced thermal acoustics was used to measure the local speed of sound in the farfield zone of extremely underexpanded jets. N-hexane at supercritical injection temperature and pressure (supercritical reservoir condition) was injected into quiescent subcritical nitrogen (with respect to the injectant). The technique's capability to quantify the nonisothermal, turbulent mixing zone of small-scale jets is demonstrated for the first time. Consistent radially resolved speed of sound profiles are presented for different axial positions and varying injection temperatures. Furthermore, an adiabatic mixing model based on nonideal thermodynamic properties is presented to extract mixture composition and temperature from the experimental speed of sound data. High fuel mass fractions of up to 94 % are found for the centerline at an axial distance of 55 diameters from the nozzle followed by a rapid decay in axial direction. This is attributed to a supercritical fuel state at the nozzle exit resulting in the injection of a high-density fluid. The obtained concentration data are complemented by existing measurements and collapsed in a similarity law. It allows for mixture prediction of underexpanded jets with supercritical reservoir condition provided that nonideal thermodynamic behavior is considered for the nozzle flow. Specifically, it is shown that the fuel concentration in the farfield zone is very sensitive to the thermodynamic state at the nozzle exit. Here, a transition from supercritical fluid to subcritical vapor state results in strongly varying fuel concentrations, which implies high impact on the mixture formation and, consequently, on the combustion characteristics.
13. Acoustical Imaging
Akiyama, Iwaki
2009-01-01
The 29th International Symposium on Acoustical Imaging was held in Shonan Village, Kanagawa, Japan, April 15-18, 2007. This interdisciplinary Symposium has been taking place every two years since 1968 and forms a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. In the course of the years the volumes in the Acoustical Imaging Series have developed and become well-known and appreciated reference works. Offering both a broad perspective on the state-of-the-art in the field as well as an in-depth look at its leading edge research, this Volume 29 in the Series contains again an excellent collection of seventy papers presented in nine major categories: Strain Imaging Biological and Medical Applications Acoustic Microscopy Non-Destructive Evaluation and Industrial Applications Components and Systems Geophysics and Underwater Imaging Physics and Mathematics Medical Image Analysis FDTD method and Other Numerical Simulations Audience Researcher...
14. Battlefield acoustics
Damarla, Thyagaraju
2015-01-01
This book presents all aspects of situational awareness in a battlefield using acoustic signals. It starts by presenting the science behind understanding and interpretation of sound signals. The book then goes on to provide various signal processing techniques used in acoustics to find the direction of sound source, localize gunfire, track vehicles, and detect people. The necessary mathematical background and various classification and fusion techniques are presented. The book contains majority of the things one would need to process acoustic signals for all aspects of situational awareness in one location. The book also presents array theory, which is pivotal in finding the direction of arrival of acoustic signals. In addition, the book presents techniques to fuse the information from multiple homogeneous/heterogeneous sensors for better detection. MATLAB code is provided for majority of the real application, which is a valuable resource in not only understanding the theory but readers, can also use the code...
15. Acoustics Research
National Oceanic and Atmospheric Administration, Department of Commerce — Fisheries acoustics data are collected from more than 200 sea-days each year aboard the FRV DELAWARE II and FRV ALBATROSS IV (decommissioned) and the FSV Henry B....
16. Analog multivariate counting analyzers
Nikitin, A V; Armstrong, T P
2003-01-01
Characterizing rates of occurrence of various features of a signal is of great importance in numerous types of physical measurements. Such signal features can be defined as certain discrete coincidence events, e.g. crossings of a signal with a given threshold, or occurrence of extrema of a certain amplitude. We describe measuring rates of such events by means of analog multivariate counting analyzers. Given a continuous scalar or multicomponent (vector) input signal, an analog counting analyzer outputs a continuous signal with the instantaneous magnitude equal to the rate of occurrence of certain coincidence events. The analog nature of the proposed analyzers allows us to reformulate many problems of the traditional counting measurements, and cast them in a form which is readily addressed by methods of differential calculus rather than by algebraic or logical means of digital signal processing. Analog counting analyzers can be easily implemented in discrete or integrated electronic circuits, do not suffer fro...
17. Low rank Multivariate regression
Giraud, Christophe
2010-01-01
We consider in this paper the multivariate regression problem, when the target regression matrix $A$ is close to a low rank matrix. Our primary interest in on the practical case where the variance of the noise is unknown. Our main contribution is to propose in this setting a criterion to select among a family of low rank estimators and prove a non-asymptotic oracle inequality for the resulting estimator. We also investigate the easier case where the variance of the noise is known and outline that the penalties appearing in our criterions are minimal (in some sense). These penalties involve the expected value of the Ky-Fan quasi-norm of some random matrices. These quantities can be evaluated easily in practice and upper-bounds can be derived from recent results in random matrix theory.
18. Multivariate analysis of bistable flow; Analisis multivariable de flujo biestable
Castillo D, R.; Ortiz V, J.; Ruiz E, J.A. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico); Calleros M, G. [CFE, Alto LUcero, Veracruz (Mexico)]. e-mail: rcd@nuclear.inin.mx
2007-07-01
In this work a bistable flow analysis with an autoregressive multivariate analysis is presented. The bistable flow happens in the boiling water nuclear reactors with external recirculation pumps, and it is presented in the bolster of discharge of the recirculation knot toward the central jet pumps. The phenomenon has two flow patterns, one with greater hydraulic lost that the other one. To irregular time intervals, the flow changes pattern in a random way. The program NOISE that it is in development in the ININ was used and that it uses a autoregressive multivariate model to determine the autoregression coefficients that contain the dynamic information of the signals and that later on they are used to obtain the relative contribution of power, which allows to settle down the influence that exists among the different analyzed variables. It was analyzed an event of bistable flow happened in a BWR5 to operation conditions of 80% power and 69% of total flow through the core. The signal flow noise in each one of the 20 jet pumps, of the power of a monitor of power average, of the motive flows of recirculation, of the controllers and of the position of the control valves in the knots, of the signals of the instrumentation of the recirculation pumps (power, current, pressure drop and suction temperature), and of the buses of where they take the feeding voltage the motors of the pumps. Among the main results it was found that the phenomenon of bistable flow affects to the pressure drop in the recirculation pump of the knot in that occur, what affects to the motor flow in the knot by what the opening system of the flow control valve of recirculation of the knot responds. (Author)
19. Hydrodynamic and acoustic analysis in 3-D of a section of main steam line to EPU conditions; Analisis hidrodinamico y acustico en 3D de una seccion de linea de vapor principal a condiciones de EPU
Centeno P, J.; Castillo J, V.; Espinosa P, G. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Area de Ingenieria en Recursos Energeticos, Av. San Rafael Atlixco No. 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Nunez C, A.; Polo L, M. A., E-mail: baldepeor21@hotmail.com [Comision Nacional de Seguridad Nuclear y Salvaguardias, Dr. Jose Ma. Barragan No. 779, Col. Narvarte, 03020 Mexico D. F. (Mexico)
2013-10-15
The objective of this word is to study the hydrodynamic and acoustic phenomenon in the main steam lines (MSLs). For this study was considered the specific case of a pipe section of the MSL, where is located the standpipe of the pressure and/or safety relief valve (SRV). In the SRV cavities originates a phenomenon known as whistling that generates a hydrodynamic disturbance of acoustic pressure waves with different tones depending of the reactor operation conditions. In the SRV cavities the propagation velocity of the wave can originate mechanical damage in the structure of the steam dryer and on free parts. The importance of studying this phenomenon resides in the safety of the integrity of the reactor pressure vessel. To dissipate the energy of the pressure wave, acoustic side branches (ASBs) are used on the standpipe of the SRVs. The ASBs are arrangements of compacted lattices similar to a porous medium, where the energy of the whistling phenomenon is dissipate and therefore the acoustic pressure load that impacts in particular to the steam dryers, and in general to the interns of the vessel, diminishes. For the analysis of the whistling phenomenon two three-dimensional (3-D) models were built, one hydrodynamic in stationary state and other acoustic for the harmonic times in transitory regimen, in which were applied techniques of Computational Fluid Dynamics. The study includes the reactor operation analysis under conditions of extended power up rate (EPU) with ASB and without ASB. The obtained results of the gauges simulated in the MSL without ASB and with ASB, show that tones with values of acoustic pressure are presented in frequency ranges between 160 and 200 Hz around 12 MPa and of 7 MPa, respectively. This attenuation of tones implies the decrease of the acoustic loads in the steam dryer and in the interns of the vessel that are designed to support pressures not more to 7.5 MPa approximately. With the above-mentioned is possible to protect the steam dryer
20. Acoustic detection of pneumothorax
Mansy, Hansen A.; Royston, Thomas J.; Balk, Robert A.; Sandler, Richard H.
2003-04-01
This study aims at investigating the feasibility of using low-frequency (pneumothorax detection were tested in dogs. In the first approach, broadband acoustic signals were introduced into the trachea during end-expiration and transmitted waves were measured at the chest surface. Pneumothorax was found to consistently decrease pulmonary acoustic transmission in the 200-1200-Hz frequency band, while less change was observed at lower frequencies (ppneumothorax states (pPneumothorax was found to be associated with a preferential reduction of sound amplitude in the 200- to 700-Hz range, and a decrease of sound amplitude variation (in the 300 to 600-Hz band) during the respiration cycle (pPneumothorax changed the frequency and decay rate of percussive sounds. These results imply that certain medical conditions may be reliably detected using appropriate acoustic measurements and analysis. [Work supported by NIH/NHLBI #R44HL61108.
1. Practical acoustic emission testing
2016-01-01
This book is intended for non-destructive testing (NDT) technicians who want to learn practical acoustic emission testing based on level 1 of ISO 9712 (Non-destructive testing – Qualification and certification of personnel) criteria. The essential aspects of ISO/DIS 18436-6 (Condition monitoring and diagnostics of machines – Requirements for training and certification of personnel, Part 6: Acoustic Emission) are explained, and readers can deepen their understanding with the help of practice exercises. This work presents the guiding principles of acoustic emission measurement, signal processing, algorithms for source location, measurement devices, applicability of testing methods, and measurement cases to support not only researchers in this field but also and especially NDT technicians.
Anosov, A. A.; Belyaev, R. V.; Klin'shov, V. V.; Mansfel'd, A. D.; Subochev, P. V.
2016-04-01
The 1D internal (core) temperature profiles for the model object (plasticine) and the human hand are reconstructed using the passive acoustothermometric broadband probing data. Thermal acoustic radiation is detected by a broadband (0.8-3.5 MHz) acoustic radiometer. The temperature distribution is reconstructed using a priori information corresponding to the experimental conditions. The temperature distribution for the heated model object is assumed to be monotonic. For the hand, we assume that the temperature distribution satisfies the heat-conduction equation taking into account the blood flow. The average error of reconstruction determined for plasticine from the results of independent temperature measurements is 0.6 K for a measuring time of 25 s. The reconstructed value of the core temperature of the hand (36°C) generally corresponds to physiological data. The obtained results make it possible to use passive broadband acoustic probing for measuring the core temperatures in medical procedures associated with heating of human organism tissues.
3. High-overtone Bulk-Acoustic Resonator gravimetric sensitivity: towards wideband acoustic spectroscopy
Rabus, D; Ballandras, S; Baron, T; Lebrasseur, E; Carry, E
2015-01-01
In the context of direct detection sensors with compact dimensions, we investigate the gravimetric sensitivity of High-overtone Bulk Acoustic Resonators, through modeling of their acoustic characteristics and experiment. The high frequency characterizing such devices is expected to induce a significant effect when the acoustic field boundary conditions are modified by a thin adlayer. Furthermore, the multimode spectral characteristics is considered for wideband acoustic spectroscopy of the adlayer, once the gravimetric sensitivity dependence of the various overtones is established. Finally, means of improving the gravimetric sensitivity by confining the acoustic field in a low acoustic-impedance layer is theoretically established.
4. Multi-sensory landscape assessment: the contribution of acoustic perception to landscape evaluation.
Gan, Yonghong; Luo, Tao; Breitung, Werner; Kang, Jian; Zhang, Tianhai
2014-12-01
In this paper, the contribution of visual and acoustic preference to multi-sensory landscape evaluation was quantitatively compared. The real landscapes were treated as dual-sensory ambiance and separated into visual landscape and soundscape. Both were evaluated by 63 respondents in laboratory conditions. The analysis of the relationship between respondent's visual and acoustic preference as well as their respective contribution to landscape preference showed that (1) some common attributes are universally identified in assessing visual, aural and audio-visual preference, such as naturalness or degree of human disturbance; (2) with acoustic and visual preferences as variables, a multi-variate linear regression model can satisfactorily predict landscape preference (R(2 )= 0.740), while the coefficients of determination for a unitary linear regression model were 0.345 and 0.720 for visual and acoustic preference as predicting factors, respectively; (3) acoustic preference played a much more important role in landscape evaluation than visual preference in this study (the former is about 4.5 times of the latter), which strongly suggests a rethinking of the role of soundscape in environment perception research and landscape planning practice.
5. Multivariate statistics exercises and solutions
Härdle, Wolfgang Karl
2015-01-01
The authors present tools and concepts of multivariate data analysis by means of exercises and their solutions. The first part is devoted to graphical techniques. The second part deals with multivariate random variables and presents the derivation of estimators and tests for various practical situations. The last part introduces a wide variety of exercises in applied multivariate data analysis. The book demonstrates the application of simple calculus and basic multivariate methods in real life situations. It contains altogether more than 250 solved exercises which can assist a university teacher in setting up a modern multivariate analysis course. All computer-based exercises are available in the R language. All R codes and data sets may be downloaded via the quantlet download center www.quantlet.org or via the Springer webpage. For interactive display of low-dimensional projections of a multivariate data set, we recommend GGobi.
6. Analysis of multivariate extreme intakes of food chemicals
Paulo, M.J.; Voet, van der H.; Wood, J.C.; Marion, G.R.; Klaveren, van J.D.
2006-01-01
A recently published multivariate Extreme Value Theory (EVT) model [Heffernan, J.E., Tawn, J.A., 2004. A conditional approach for multivariate extreme values (with discussion). Journal of the Royal Statistical Society Series B 66 (3), 497¿546] is applied to the estimation of population risks associa
7. Acoustic biosensors
Fogel, Ronen; Seshia, Ashwin A.
2016-01-01
Resonant and acoustic wave devices have been researched for several decades for application in the gravimetric sensing of a variety of biological and chemical analytes. These devices operate by coupling the measurand (e.g. analyte adsorption) as a modulation in the physical properties of the acoustic wave (e.g. resonant frequency, acoustic velocity, dissipation) that can then be correlated with the amount of adsorbed analyte. These devices can also be miniaturized with advantages in terms of cost, size and scalability, as well as potential additional features including integration with microfluidics and electronics, scaled sensitivities associated with smaller dimensions and higher operational frequencies, the ability to multiplex detection across arrays of hundreds of devices embedded in a single chip, increased throughput and the ability to interrogate a wider range of modes including within the same device. Additionally, device fabrication is often compatible with semiconductor volume batch manufacturing techniques enabling cost scalability and a high degree of precision and reproducibility in the manufacturing process. Integration with microfluidics handling also enables suitable sample pre-processing/separation/purification/amplification steps that could improve selectivity and the overall signal-to-noise ratio. Three device types are reviewed here: (i) bulk acoustic wave sensors, (ii) surface acoustic wave sensors, and (iii) micro/nano-electromechanical system (MEMS/NEMS) sensors. PMID:27365040
8. General considerations regarding the importance of a study of the acoustic conditions of churches with historic and artistic value in Mexico. The case of baroque architecture
Rodriguez Manzo, Fausto; Kotasek Gonzalez, Eduardo
2002-11-01
This paper deals with the problem of old churches in Mexico with historic and artistic value. Some churches in the baroque period in Mexico are examples of a kind of building used as concert and conference halls. However there is a lack of acoustic knowledge of these kinds of architectural spaces in Mexico. This knowledge will also augment that of the historic, artistic and architectural point of view, and be a foundation for high-quality renovation and preservation projects for this type of building. The particular characteristics of some of the most significant churches of this period are presented as well as a first architectural acoustics review of them.
9. Droplets Acoustics
Dahan, Raphael; Carmon, Tal
2015-01-01
Contrary to their capillary resonances (Rayleigh, 1879) and their optical resonances (Ashkin, 1977), droplets acoustical resonances were rarely considered. Here we experimentally excite, for the first time, the acoustical resonances of a droplet that relies on sound instead of capillary waves. Droplets vibrations at 37 MHz rates and 100 quality factor are optically excited and interrogated at an optical threshold of 68 microWatt. Our vibrations span a spectral band that is 1000 times higher when compared with drops previously-studied capillary vibration.
10. Multivariate Bioclimatic Ecosystem Change Approaches
2015-02-06
conclude that an analogous patch did not exist. It must exist somewhere, but some of the other MVA techniques were restricted by the mathematical ...found that the Primarily Analogous Multivariate approach developed during this research clearly distinguished itself from the other five approaches in...Principally Analogous Multivariate (PAM) approach ............................................... 29 4.6.1 Introduction to the PAM approach
11. Gamma butyrolactone (GBL) and gamma valerolactone (GVL): similarities and differences in their effects on the acoustic startle reflex and the conditioned enhancement of startle in the rat.
Marinetti, Laureen J; Leavell, Bonita J; Jones, Calleen M; Hepler, Bradford R; Isenschmid, Daniel S; Commissaris, Randall L
2012-06-01
Gamma butyrolactone (GBL) is metabolized to gamma hydroxybutyrate (GHB) in the body. GHB is a DEA Schedule 1 compound; GBL is a DEA List 1 chemical. Gamma valerolactone (GVL) is the 4-methyl analog of GBL; GVL is metabolized to 4-methyl-GHB; GVL is NOT metabolized to GBL or GHB. The effects of GBL (18.75-150 mg/kg), GVL (200-1600 mg/kg) or vehicle on the acoustic startle reflex (ASR), and the classically-conditioned enhancement of startle, the Startle Anticipated Potentiation of Startle (SAPS) response were studied in male rats. Both compounds produced a dose-dependent reduction of ASR, with GBL 5-7 times more potent than GVL. In contrast, GBL treatment significantly reduced SAPS at doses that exerted only moderate effects on ASR, whereas GVL exerted little or no effect on the SAPS, except at doses that produced pronounced reductions in Noise Alone ASR. In a second experiment, rats were tested for Noise Alone ASR behavior following treatment with a single mid-range dose of GBL (75 mg/kg), GVL (400mg/kg) or vehicle; immediately following startle testing the animals were sacrificed and their brains and blood were collected for determination of GHB, 4-methyl-GHB, GBL and GVL. GHB was found in measurable concentrations in all of the blood specimens and 6 (of 8) of the brain specimens from the GBL-treated subjects. 4-Methyl-GHB was found in measurable concentrations in all of the blood and brain specimens of the GVL-treated subjects; the change in startle amplitude was inversely correlated to the brain concentrations of these compounds. These findings confirm the differences in the metabolic fate of GBL and GVL as pro-drugs for the formation of GHB and 4-methyl-GHB, respectively. Moreover, the dissimilarity in effect profile for GBL and GVL on ASR versus SAPS behaviors suggests that different receptor(s) may be involved in mediating these behavioral effects.
12. Modeling Multivariate Volatility Processes: Theory and Evidence
Jelena Z. Minovic
2009-05-01
Full Text Available This article presents theoretical and empirical methodology for estimation and modeling of multivariate volatility processes. It surveys the model specifications and the estimation methods. Multivariate GARCH models covered are VEC (initially due to Bollerslev, Engle and Wooldridge, 1988, diagonal VEC (DVEC, BEKK (named after Baba, Engle, Kraft and Kroner, 1995, Constant Conditional Correlation Model (CCC, Bollerslev, 1990, Dynamic Conditional Correlation Model (DCC models of Tse and Tsui, 2002, and Engle, 2002. I illustrate approach by applying it to daily data from the Belgrade stock exchange, I examine two pairs of daily log returns for stocks and index, report the results obtained, and compare them with the restricted version of BEKK, DVEC and CCC representations. The methods for estimation parameters used are maximum log-likehood (in BEKK and DVEC models and twostep approach (in CCC model.
13. A primer of multivariate statistics
Harris, Richard J
2014-01-01
Drawing upon more than 30 years of experience in working with statistics, Dr. Richard J. Harris has updated A Primer of Multivariate Statistics to provide a model of balance between how-to and why. This classic text covers multivariate techniques with a taste of latent variable approaches. Throughout the book there is a focus on the importance of describing and testing one's interpretations of the emergent variables that are produced by multivariate analysis. This edition retains its conversational writing style while focusing on classical techniques. The book gives the reader a feel for why
14. Meshless RBF based pseudospectral solution of acoustic wave equation
Mishra, Pankaj K
2015-01-01
Chebyshev pseudospectral (PS) methods are reported to provide highly accurate solution using polynomial approximation. Use of polynomial basis functions in PS algorithms limits the formulation to univariate systems constraining it to tensor product grids for multi-dimensions. Recent studies have shown that replacing the polynomial by radial basis functions in pseudospectral method (RBF-PS) has the advantage of using irregular grids for multivariate systems. A RBF-PS algorithm has been presented here for the numerical solution of inhomogeneous Helmholtz's equation using Gaussian RBF for derivative approximation. Efficacy of RBF approximated derivatives has been checked through error analysis comparison with PS method. Comparative study of PS, RBF-PS and finite difference approach for the solution of a linear boundary value problem has been performed. Finally, a typical frequency domain acoustic wave propagation problem has been solved using Dirichlet boundary condition and a point source. The algorithm present...
15. Parameter Estimation in Multivariate Gamma Distribution
V S Vaidyanathan
2015-05-01
Full Text Available Multivariate gamma distribution finds abundant applications in stochastic modelling, hydrology and reliability. Parameter estimation in this distribution is a challenging one as it involves many parameters to be estimated simultaneously. In this paper, the form of multivariate gamma distribution proposed by Mathai and Moschopoulos [10] is considered. This form has nice properties in terms of marginal and conditional densities. A new method of estimation based on optimal search is proposed for estimating the parameters using the marginal distributions and the concepts of maximum likelihood, spacings and least squares. The proposed methodology is easy to implement and is free from calculus. It optimizes the objective function by searching over a wide range of values and determines the estimate of the parameters. The consistency of the estimates is demonstrated in terms of mean, standard deviation and mean square error through simulation studies for different choices of parameters.
16. conditions
M. Venkatesulu
1996-01-01
Full Text Available Solutions of initial value problems associated with a pair of ordinary differential systems (L1,L2 defined on two adjacent intervals I1 and I2 and satisfying certain interface-spatial conditions at the common end (interface point are studied.
17. Multivariate Generalized Multiscale Entropy Analysis
Anne Humeau-Heurtier
2016-11-01
Full Text Available Multiscale entropy (MSE was introduced in the 2000s to quantify systems’ complexity. MSE relies on (i a coarse-graining procedure to derive a set of time series representing the system dynamics on different time scales; (ii the computation of the sample entropy for each coarse-grained time series. A refined composite MSE (rcMSE—based on the same steps as MSE—also exists. Compared to MSE, rcMSE increases the accuracy of entropy estimation and reduces the probability of inducing undefined entropy for short time series. The multivariate versions of MSE (MMSE and rcMSE (MrcMSE have also been introduced. In the coarse-graining step used in MSE, rcMSE, MMSE, and MrcMSE, the mean value is used to derive representations of the original data at different resolutions. A generalization of MSE was recently published, using the computation of different moments in the coarse-graining procedure. However, so far, this generalization only exists for univariate signals. We therefore herein propose an extension of this generalized MSE to multivariate data. The multivariate generalized algorithms of MMSE and MrcMSE presented herein (MGMSE and MGrcMSE, respectively are first analyzed through the processing of synthetic signals. We reveal that MGrcMSE shows better performance than MGMSE for short multivariate data. We then study the performance of MGrcMSE on two sets of short multivariate electroencephalograms (EEG available in the public domain. We report that MGrcMSE may show better performance than MrcMSE in distinguishing different types of multivariate EEG data. MGrcMSE could therefore supplement MMSE or MrcMSE in the processing of multivariate datasets.
18. Analysis of acoustic emission signals of fatigue crack growth and corrosion processes. Investigation of the possibilities for continuous condition monitoring of transport containers by acoustic emission testing; Analyse der Schallemissionssignale aus Ermuedungsrisswachstum und Korrosionsprozessen. Untersuchung der Moeglichkeiten fuer die kontinuierliche Zustandsueberwachung von Transportbehaeltern mittels Schallemissionspruefung
Wachsmuth, Janne
2016-05-01
Fatigue crack growth and active corrosion processes are the main causes of structural failures of transport products like road tankers, railway tank cars and ships. To prevent those failures, preventive, time-based maintenance is performed. However, preventive inspections are costly and include the risk of not detecting a defect, which could lead to a failure within the next service period. An alternative is the idea of continuous monitoring of the whole structure by means of acoustic emission testing (AT). With AT, defects within the material shall be detected and repaired directly after their appearance. Acoustic emission testing is an online non-destructive testing method. Acoustic emission (AE) arises from changes within the material and is transported by elastic waves through the material. If the AE event generates enough energy, the elastic wave propagates to the boundaries of the component, produces a displacement in the picometre scale and can be detected by a piezoelectric sensor. The sensor produces an electrical signal. From this AE signal, AE features such as the maximum amplitude or the frequency can be extracted. Methods of signal analysis are used to investigate the time and frequency dependency of signal groups. The purpose of the signal analysis is to connect the AE signal with the originating AE source. If predefined damage mechanisms are identified, referencing the damage condition of the structure is possible. Acoustic emission from events of the actual crack propagation process can for example lead to the crack growth rate or the stress intensity factor, both specific values from fracture mechanics. A new development in the domain of acoustic emission testing is the pattern recognition of AE signals. Specific features are extracted from the AE signals to assign them to their damage mechanisms. In this thesis the AE signals from the damage mechanisms corrosion and fatigue crack growth are compared and analysed. The damage mechanisms were
19. A Martian acoustic anemometer.
Banfield, Don; Schindel, David W; Tarr, Steve; Dissly, Richard W
2016-08-01
An acoustic anemometer for use on Mars has been developed. To understand the processes that control the interaction between surface and atmosphere on Mars, not only the mean winds, but also the turbulent boundary layer, the fluxes of momentum, heat and molecular constituents between surface and atmosphere must be measured. Terrestrially this is done with acoustic anemometers, but the low density atmosphere on Mars makes it challenging to adapt such an instrument for use on Mars. This has been achieved using capacitive transducers and pulse compression, and was successfully demonstrated on a stratospheric balloon (simulating the Martian environment) and in a dedicated Mars Wind Tunnel facility. This instrument achieves a measurement accuracy of ∼5 cm/s with an update rate of >20 Hz under Martian conditions.
20. Multivariable Intelligent Decoupling Control System and its Application
TianYou CHAI; Heng YUE
2005-01-01
Many industrial processes have compositive complexities including multivariable, strong coupling, nonlinearity, time-variant and operating condition variations. Combining multivariable adaptive decoupling control with neural networks, this paper presents a multivariable neural networkbased decoupling control algorithm. This control algorithm is integrated with distributed control technique and intelligent control technique, and a three-leveled intelligent decoupling control system consisting of basic control level, coordinating control level, and management and decision level is developed. The configuration and function of the control system are discussed in detail. This system has been successfully applied in ball mill pulverizing systems of 200MW power units, and remarkable benefits have been obtained.
1. Multivariate ultrametric root counting
Avendano, Martin
2011-01-01
Let $K$ be a field, complete with respect to a discrete non-archimedian valuation and let $k$ be the residue field. Consider a system $F$ of $n$ polynomial equations in $K\\vars$. Our first result is a reformulation of the classical Hensel's Lemma in the language of tropical geometry: we show sufficient conditions (semiregularity at $w$) that guarantee that the first digit map $\\delta:(K^\\ast)^n\\to(k^\\ast)^n$ is a one to one correspondence between the solutions of $F$ in $(K^\\ast)^n$ with valuation $w$ and the solutions in $(k^\\ast)^n$ of the initial form system ${\\rm in}_w(F)$. Using this result, we provide an explicit formula for the number of solutions in $(K^\\ast)^n$ of a certain class of systems of polynomial equations (called regular), characterized by having finite tropical prevariety, by having initial forms consisting only of binomials, and by being semiregular at any point in the tropical prevariety. Finally, as a consequence of the root counting formula, we obtain the expected number of roots in (K... 2. Applied multivariate statistics with R Zelterman, Daniel 2015-01-01 This book brings the power of multivariate statistics to graduate-level practitioners, making these analytical methods accessible without lengthy mathematical derivations. Using the open source, shareware program R, Professor Zelterman demonstrates the process and outcomes for a wide array of multivariate statistical applications. Chapters cover graphical displays, linear algebra, univariate, bivariate and multivariate normal distributions, factor methods, linear regression, discrimination and classification, clustering, time series models, and additional methods. Zelterman uses practical examples from diverse disciplines to welcome readers from a variety of academic specialties. Those with backgrounds in statistics will learn new methods while they review more familiar topics. Chapters include exercises, real data sets, and R implementations. The data are interesting, real-world topics, particularly from health and biology-related contexts. As an example of the approach, the text examines a sample from the B... 3. Strategies for Industrial Multivariable Control Hangstrup, M. dynamics and gains strongly depend upon one or more physical parameters characterizing the operating point. This class covers many industrial systems such as airplanes, ships, robots and process control systems. Power plant boilers are representatives for process control systems in general. The dynamics......Multivariable control strategies well-suited for industrial applications are suggested. The strategies combine the practical advantages of conventional SISO control schemes and -technology with the potential of multivariable controllers. Special emphasis is put on parameter-varying systems whose...... and gains of power plant boilers strongly depend upon the load (instantaneous power production). This non-linear behavior suggests the use of gain-scheduling. For parameter-varying systems the multivariable control strategies can hence be divided into the following subsequent steps: choice of architecture... 4. Multivariate regression analytical method based on heuristic constructed variable under condition of incomplete data%数据缺失条件下基于启发式构元的多元回归分析方法 张希翔; 李陶深 2012-01-01 Regression analysis is often used for filling and predicting incomplete data, whereas it has some flaws when constructing regression equation, the independent variable form is fixed and single. In order to solve the problem, the paper proposed an improved multivariate regression analytical method based on heuristic constructed variable. Firstly, the existing variables' optimized combination forms were found by means of greedy algorithm, then the new constructed variable for multivariate regression analysis was chosen to get a better goodness of fit. Results of calculating and estimating incomplete data of wheat stalks' mechanical strength prove thai the proposed method is feasible and effective, and it can get a better goodness of fit when predicting incomplete data.%传统的多元回归分析方法可以对缺失数据进行预测填补,但它在构造回归方程时存在自变量形式较为固定、单一等不足.为此,提出一种基于启发式构元的多元回归分析方法,通过贪婪算法找出现有变量的优化组合形式,选取若干新构变量进行回归分析,从而得到更好的拟合优度.通过对案例中小麦茎秆机械强度缺失数据信息进行仿真计算和评估,证实了方法的有效性.算例结果表明该方法运用在缺失数据预测中拥有较好的精准性. 5. Propagation behavior of acoustic wave in wood Huadong Xu; Guoqi Xu; Lihai Wang; Lei Yu 2014-01-01 We used acoustic tests on a quarter-sawn poplar timbers to study the effects of wood anisotropy and cavity defects on acoustic wave velocity and travel path, and we investigated acoustic wave propagation behavior in wood. The timber specimens were first tested in unmodified condition and then tested after introduction of cavity defects of varying sizes to quantify the transmitting time of acoustic waves in laboratory conditions. Two-dimensional acoustic wave contour maps on the radial section of specimens were then simulated and analyzed based on the experimental data. We tested the relationship between wood grain and acoustic wave velocity as waves passed in various directions through wood. Wood anisotropy has significant effects on both velocity and travel path of acoustic waves, and the velocity of waves passing longitudinally through timbers exceeded the radial velocity. Moreover, cavity defects altered acoustic wave time contours on radial sections of timbers. Acous-tic wave transits from an excitation point to the region behind a cavity in defective wood more slowly than in intact wood. 6. Building multivariate systems biology models Kirwan, G.M.; Johansson, E.; Kleemann, R.; Verheij, E.R.; Wheelock, A.M.; Goto, S.; Trygg, J.; Wheelock, C.E. 2012-01-01 Systems biology methods using large-scale "omics" data sets face unique challenges: integrating and analyzing near limitless data space, while recognizing and removing systematic variation or noise. Herein we propose a complementary multivariate analysis workflow to both integrate "omics" data from 7. The Multivariate Gaussian Probability Distribution Ahrendt, Peter 2005-01-01 This technical report intends to gather information about the multivariate gaussian distribution, that was previously not (at least to my knowledge) to be found in one place and written as a reference manual. Additionally, some useful tips and tricks are collected that may be useful in practical... 8. Liquid rocket combustion chamber acoustic characterization Cândido Magno de Souza 2010-09-01 Full Text Available Over the last 40 years, many solid and liquid rocket motors have experienced combustion instabilities. Among other causes, there is the interaction of acoustic modes with the combustion and/or fluid dynamic processes inside the combustion chamber. Studies have been showing that, even if less than 1% of the available energy is diverted to an acoustic mode, combustion instability can be generated. On one hand, this instability can lead to ballistic pressure changes, couple with other propulsion systems such as guidance or thrust vector control, and in the worst case, cause motor structural failure. In this case, measures, applying acoustic techniques, must be taken to correct/minimize these influences on the combustion. The combustion chamber acoustic behavior in operating conditions can be estimated by considering its behavior in room conditions. In this way, acoustic tests can be easily performed, thus identifying the cavity modes. This paper describes the procedures to characterize the acoustic behavior in the inner cavity of four different configurations of a combustion chamber. Simple analytical models are used to calculate the acoustic resonance frequencies and these results are compared with acoustic natural frequencies measured at room conditions. Some comments about the measurement procedures are done, as well as the next steps for the continuity of this research. The analytical and experimental procedures results showed good agreement. However, limitations on high frequency band as well as in the identification of specific kinds of modes indicate that numerical methods able to model the real cavity geometry and an acoustic experimental modal analysis may be necessary for a more complete analysis. Future works shall also consider the presence of passive acoustic devices such as baffles and resonators capable of introducing damping and avoiding or limiting acoustic instabilities. 9. On Modeling Eavesdropping Attacks in Underwater Acoustic Sensor Networks † Qiu Wang; Hong-Ning Dai; Xuran Li; Hao Wang; Hong Xiao 2016-01-01 The security and privacy of underwater acoustic sensor networks has received extensive attention recently due to the proliferation of underwater activities. This paper proposes an analytical model to investigate the eavesdropping attacks in underwater acoustic sensor networks. Our analytical framework considers the impacts of various underwater acoustic channel conditions (such as the acoustic signal frequency, spreading factor and wind speed) and different hydrophones (isotropic hydrophones ... 10. Use of acoustic vortices in acoustic levitation Cutanda Henriquez, Vicente; Santillan, Arturo Orozco; Juhl, Peter Møller 2009-01-01 Acoustic fields are known to exert forces on the surfaces of objects. These forces are noticeable if the sound pressure is sufficiently high. Two phenomena where acoustic forces are relevant are: i) acoustic levitation, where strong standing waves can hold small objects at certain positions......, counterbalancing their weight, and ii) acoustic vortices, spinning sound fields that can impinge angular momentum and cause rotation of objects. In this contribution, both force-creating sound fields are studied by means of numerical simulations. The Boundary Element Method is employed to this end. The simulation...... of acoustical vortices uses an efficient numerical implementation based on the superposition of two orthogonal sound fields with a delay of 90° between them. It is shown that acoustic levitation and the use of acoustic vortices can be combined to manipulate objects in an efficient and controlled manner without... 11. Acoustic cryocooler Swift, Gregory W.; Martin, Richard A.; Radenbaugh, Ray 1990-01-01 An acoustic cryocooler with no moving parts is formed from a thermoacoustic driver (TAD) driving a pulse tube refrigerator (PTR) through a standing wave tube. Thermoacoustic elements in the TAD are spaced apart a distance effective to accommodate the increased thermal penetration length arising from the relatively low TAD operating frequency in the range of 15-60 Hz. At these low operating frequencies, a long tube is required to support the standing wave. The tube may be coiled to reduce the overall length of the cryocooler. One or two PTR's are located on the standing wave tube adjacent antinodes in the standing wave to be driven by the standing wave pressure oscillations. It is predicted that a heat input of 1000 W at 1000 K will maintian a cooling load of 5 W at 80 K. 12. Unexpectedly Large Surface Gravities for Acoustic Horizons? Liberati, S; Visser, M; Liberati, Stefano; Sonego, Sebastiano; Visser, Matt 2000-01-01 Acoustic black holes are fluid dynamic analogs of general relativistic black holes, wherein the behaviour of sound waves in a moving fluid acts as an analog for scalar fields propagating in a gravitational background. Acoustic horizons possess many of the properties more normally associated with the event horizons of general relativity, up to and including Hawking radiation. They have received much attention because it would seem to be much easier to experimentally create an acoustic horizon than to create an event horizon. We wish to point out some potential difficulties (and opportunities) in actually setting up an experiment that possesses an acoustic horizon. We show that in zero-viscosity, stationary fluid flow with generic boundary conditions, the creation of an acoustic horizon is accompanied by a formally infinite surface gravity'', and a formally infinite Hawking flux. Only by applying a suitable non-constant external body force, and for very specific boundary conditions on the flow, can these quan... 13. Acoustic resonance for nonmetallic mine detection Kercel, S.W. 1998-04-01 The feasibility of acoustic resonance for detection of plastic mines was investigated by researchers at the Oak Ridge National Laboratorys Instrumentation and Controls Division under an internally funded program. The data reported in this paper suggest that acoustic resonance is not a practical method for mine detection. Representative small plastic anti-personnel mines were tested, and were found to not exhibit detectable acoustic resonances. Also, non-metal objects known to have strong acoustic resonances were tested with a variety of excitation techniques, and no practical non-contact method of exciting a consistently detectable resonance in a buried object was discovered. Some of the experimental data developed in this work may be useful to other researchers seeking a method to detect buried plastic mines. A number of excitation methods and their pitfalls are discussed. Excitation methods that were investigated include swept acoustic, chopped acoustic, wavelet acoustic, and mechanical shaking. Under very contrived conditions, a weak response that could be attributed to acoustic resonance was observed, but it does not appear to be practical as a mine detection feature. Transfer properties of soil were investigated. Impulse responses of several representative plastic mines were investigated. Acoustic leakage coupling, and its implications as a disruptive mechanism were investigated. 14. 利用声发射技术检测储罐的腐蚀损伤状态%Acoustic Emission Testing Technology for the Corrosion Destruction Condition of Vessels 钟建强; 柳颖; 杨娟; 王汉功 2011-01-01 The study is made to prove the feasibility of using the acoustic emission technology to detect tbe corrosion destruction condition of the liquid rocket oxidant vessels, whose main structure material is 5A03 aluminum alloy. The simulative test project using different concentrations of nitric acid to corrode 5A03 alloy is made according to the corrosion mechanism of the oxidant vessels in use. The corrosion process of 5A03 aluminium alloy is monitored by the acoustic emission technology for the first time in this article. The results show that the hits number can reflect the corrosion destruction condition of the alloy, and the distribution of the characteristic parameters, such as rise time, duration, ring-down counts and energy, is different obviously, and can be differed by 90% distribution interval. At last, the BP artificial neural network is build up to judge the corrosion damage degree with high accuracy, and the acoustic emission technology is proved feasible and predominant to inspect the corrosion condition of the oxidant vessel.%研究了采用声发射技术检测大型氧化剂储罐腐蚀损伤状态的可行性。根据液体火箭氧化剂储罐主要的结构材料5A03铝合金在实际使用中的腐蚀机理，选取不同浓度的硝酸作为腐蚀介质，建立5A03铝合金腐蚀的试验方案，利用声发射技术对腐蚀过程进行监测，获得了各浓度水平下的声发射信号。试验结果表明，声发射信号撞击数的多少能够反映合金不同的腐蚀损伤程度，不同浓度硝酸中5A03铝合金腐蚀声发射信号的上升时间、持续时间、振铃计数、能量等特征参数的分布具有较大差异，可通过90％的分布区间加以区分。利用所建立的BP神经网络能够以很高的正确率对5A03铝合金储罐腐蚀损伤程度进行模式识别。 15. Focusing of Acoustic Waves through Acoustic Materials with Subwavelength Structures Xiao, Bingmu 2013-05-01 In this thesis, wave propagation through acoustic materials with subwavelength slits structures is studied. Guided by the findings, acoustic wave focusing is achieved with a specific material design. By using a parameter retrieving method, an effective medium theory for a slab with periodic subwavelength cut-through slits is successfully derived. The theory is based on eigenfunction solutions to the acoustic wave equation. Numerical simulations are implemented by the finite-difference time-domain (FDTD) method for the two-dimensional acoustic wave equation. The theory provides the effective impedance and refractive index functions for the equivalent medium, which can reproduce the transmission and reflection spectral responses of the original structure. I analytically and numerically investigate both the validity and limitations of the theory, and the influences of material and geometry on the effective spectral responses are studied. Results show that large contrasts in impedance and density are conditions that validate the effective medium theory, and this approximation displays a better accuracy for a thick slab with narrow slits in it. Based on the effective medium theory developed, a design of a at slab with a snake shaped" subwavelength structure is proposed as a means of achieving acoustic focusing. The property of focusing is demonstrated by FDTD simulations. Good agreement is observed between the proposed structure and the equivalent lens pre- dicted by the theory, which leads to robust broadband focusing by a thin at slab. 16. Nonnegative Decomposition of Multivariate Information Williams, Paul L 2010-01-01 Of the various attempts to generalize information theory to multiple variables, the most widely utilized, interaction information, suffers from the problem that it is sometimes negative. Here we reconsider from first principles the general structure of the information that a set of sources provides about a given variable. We begin with a new definition of redundancy as the minimum information that any source provides about each possible outcome of the variable, averaged over all possible outcomes. We then show how this measure of redundancy induces a lattice over sets of sources that clarifies the general structure of multivariate information. Finally, we use this redundancy lattice to propose a definition of partial information atoms that exhaustively decompose the Shannon information in a multivariate system in terms of the redundancy between synergies of subsets of the sources. Unlike interaction information, the atoms of our partial information decomposition are never negative and always support a clear i... 17. Sparse Linear Identifiable Multivariate Modeling Henao, Ricardo; Winther, Ole 2011-01-01 In this paper we consider sparse and identifiable linear latent variable (factor) and linear Bayesian network models for parsimonious analysis of multivariate data. We propose a computationally efficient method for joint parameter and model inference, and model comparison. It consists of a fully...... Bayesian hierarchy for sparse models using slab and spike priors (two-component δ-function and continuous mixtures), non-Gaussian latent factors and a stochastic search over the ordering of the variables. The framework, which we call SLIM (Sparse Linear Identifiable Multivariate modeling), is validated...... and bench-marked on artificial and real biological data sets. SLIM is closest in spirit to LiNGAM (Shimizu et al., 2006), but differs substantially in inference, Bayesian network structure learning and model comparison. Experimentally, SLIM performs equally well or better than LiNGAM with comparable... 18. Visualization of Multivariate Metabolomic Data ZHOU Jun; CAO Bei; ZHENG Tian; LIU Lin-sheng; GUO Sheng; DUAN Jin-ao; AA Ji-ye; WANG Guang-ji; ZHANG Feng-yi; GU Rong-rong; WANG Xin-wen; ZHAO Chun-yan; LI Meng-jie; SHI Jian 2011-01-01 Objective Although principal components analysis profiles greatly facilitate the visualization and interpretation of the multivariate data,the quantitative concepts in both scores plot and loading plot are rather obscure.This article introduced three profiles that assisted the better understanding of metabolomic data.Methods The discriminatory profile,heat map,and statistic profile were developed to visualize the multivariate data obtained from high-throughput GC-TOF-MS analysis.Results The discriminatory profile and heat map obviously showed the discriminatory metabolites between the two groups,while the statistic profile showed the potential markers of statistic significance.Conclusion The three types of profiles greatly facilitate our understanding of the metabolomic data and the identification of the potential markers. 19. Flotation control -- A multivariable stabilizer Schubert, J.H.; Henning, R.G.D.; Hulbert, D.G.; Craig, I.K. [Mintek, Randburg (South Africa) 1995-12-31 This paper presents a stabilizing controller for flotation plants which uses a quasi-multivariable technique. The controller monitors all the levels in the plant, and by anticipating interactions between various parts of the plant, is able to stabilize the plant far more successfully than the normal plant control. Once stabilizing control has been achieved, optimization of the process becomes easier and more sustainable. An estimate of the improvement in metallurgical performance is made and a singular value analysis was conducted to verify that the multivariable algorithm will theoretically control better than a collection of individual PID loops. Metallurgical results are presented to show that the improvements are attainable in practice. Control by the Mintek algorithm was alternated with normal plant control, to show that the improvements are statistically significant. 20. Multivariate Evolutionary Analyses in Astrophysics Fraix-Burnet, Didier 2011-01-01 The large amount of data on galaxies, up to higher and higher redshifts, asks for sophisticated statistical approaches to build adequate classifications. Multivariate cluster analyses, that compare objects for their global similarities, are still confidential in astrophysics, probably because their results are somewhat difficult to interpret. We believe that the missing key is the unavoidable characteristics in our Universe: evolution. Our approach, known as Astrocladistics, is based on the evolutionary nature of both galaxies and their properties. It gathers objects according to their "histories" and establishes an evolutionary scenario among groups of objects. In this presentation, I show two recent results on globular clusters and earlytype galaxies to illustrate how the evolutionary concepts of Astrocladistics can also be useful for multivariate analyses such as K-means Cluster Analysis. 1. Multivariate Matrix-Exponential Distributions Bladt, Mogens; Nielsen, Bo Friis 2010-01-01 In this article we consider the distributions of non-negative random vectors with a joint rational Laplace transform, i.e., a fraction between two multi-dimensional polynomials. These distributions are in the univariate case known as matrix-exponential distributions, since their densities can...... be written as linear combinations of the elements in the exponential of a matrix. For this reason we shall refer to multivariate distributions with rational Laplace transform as multivariate matrix-exponential distributions (MVME). The marginal distributions of an MVME are univariate matrix......-exponential distributions. We prove a characterization that states that a distribution is an MVME distribution if and only if all non-negative, non-null linear combinations of the coordinates have a univariate matrix-exponential distribution. This theorem is analog to a well-known characterization theorem... 2. Multivariate Adaptive Regression Splines (Preprint) 1990-08-01 characteristics of olive oils as a function of production year by multivariate methods. La Revista Italiana delle Sostanze Grasse, 60, Oct. . Friedman, J...Projection pursuit 76, 817-823. Friedman, J. H. and Wright, M. J. (1981). A nested partitioni: integration. ACM Trans. Math. Software, March. simonious...data. Proc. 1964 ACM Nat. Conf., 517-524. Shumaker, L. L. (1976). Fitting surfaces to scattered data. In Approximation Theory III, G. G. Lorentz, C 3. Estadística multivariable Polo Miranda, Carlos 2002-01-01 Este libro ha sido elaborado y editado para los estudios de segundo ciclo de Ingeniería de Organización Industrial, que se imparten en la ETSEIT de la UPC. La estadística multivariable permite el análisis y la interpretación del comportamiento de múltiples variables de interés, asociadas a un mismo individuo, de las que se dispone de un gran número de observaciones. 4. Measurement of acoustical characteristics of mosques in Saudi Arabia Abdou, Adel A. 2003-03-01 The study of mosque acoustics, with regard to acoustical characteristics, sound quality for speech intelligibility, and other applicable acoustic criteria, has been largely neglected. In this study a background as to why mosques are designed as they are and how mosque design is influenced by worship considerations is given. In the study the acoustical characteristics of typically constructed contemporary mosques in Saudi Arabia have been investigated, employing a well-known impulse response. Extensive field measurements were taken in 21 representative mosques of different sizes and architectural features in order to characterize their acoustical quality and to identify the impact of air conditioning, ceiling fans, and sound reinforcement systems on their acoustics. Objective room-acoustic indicators such as reverberation time (RT) and clarity (C50) were measured. Background noise (BN) was assessed with and without the operation of air conditioning and fans. The speech transmission index (STI) was also evaluated with and without the operation of existing sound reinforcement systems. The existence of acoustical deficiencies was confirmed and quantified. The study, in addition to describing mosque acoustics, compares design goals to results obtained in practice and suggests acoustical target values for mosque design. The results show that acoustical quality in the investigated mosques deviates from optimum conditions when unoccupied, but is much better in the occupied condition. 5. Acoustic clouds: standing sound waves around a black hole analogue Benone, Carolina L; Herdeiro, Carlos; Radu, Eugen 2014-01-01 Under certain conditions sound waves in fluids experience an acoustic horizon with analogue properties to those of a black hole event horizon. In particular, a draining bathtub-like model can give rise to a rotating acoustic horizon and hence a rotating black hole (acoustic) analogue. We show that sound waves, when enclosed in a cylindrical cavity, can form stationary waves around such rotating acoustic black holes. These acoustic perturbations display similar properties to the scalar clouds that have been studied around Kerr and Kerr-Newman black holes; thus they are dubbed acoustic clouds. We make the comparison between scalar clouds around Kerr black holes and acoustic clouds around the draining bathtub explicit by studying also the properties of scalar clouds around Kerr black holes enclosed in a cavity. Acoustic clouds suggest the possibility of testing, experimentally, the existence and properties of black hole clouds, using analog models. 6. Springer Handbook of Acoustics Rossing, Thomas D 2007-01-01 Acoustics, the science of sound, has developed into a broad interdisciplinary field encompassing the academic disciplines of physics, engineering, psychology, speech, audiology, music, architecture, physiology, neuroscience, and others. The Springer Handbook of Acoustics is an unparalleled modern handbook reflecting this richly interdisciplinary nature edited by one of the acknowledged masters in the field, Thomas Rossing. Researchers and students benefit from the comprehensive contents spanning: animal acoustics including infrasound and ultrasound, environmental noise control, music and human speech and singing, physiological and psychological acoustics, architectural acoustics, physical and engineering acoustics, signal processing, medical acoustics, and ocean acoustics. This handbook reviews the most important areas of acoustics, with emphasis on current research. The authors of the various chapters are all experts in their fields. Each chapter is richly illustrated with figures and tables. The latest rese... 7. Evaluating multivariate GARCH models in the Nordic electricity markets Malo, P.; Kanto, A. 2005-07-01 This paper considers a variety of specification tests for multivariate GARCH models that are used in dynamic hedging in the electricity markets. The test statistics include the robust conditional moments tests for sign-size bias along with the recently introduced copula tests for an appropriate dependence structure. We consider this effort worthwhile, since quite often the tests of multivariate GARCH models are easily omitted and the models become selected ad-hoc depending on the results they generate. Hedging performance comparisons, in terms of unconditional and conditional ex-post variance portfolio reduction, are conducted. (orig.) 8. Minimal inversion, command matching and disturbance decoupling in multivariable systems Seraji, H. 1989-01-01 The present treatment of the related problems of minimal inversion and perfect output control in linear multivariable systems uses a simple analytical expression for the inverse of a square multivariate system's transfer-function matrix to construct a minimal-order inverse of the system. Because the poles of the minimal-order inverse are the transmission zeros of the system, necessary and sufficient conditions for the inverse system's stability are simply stated in terms of the zero polynomial of the original system. A necessary and sufficient condition for the existence of the required controllers is that the plant zero polynomial be neither identical to zero nor unstable. 9. Classroom acoustics: Three pilot studies Smaldino, Joseph J. 2005-04-01 This paper summarizes three related pilot projects designed to focus on the possible effects of classroom acoustics on fine auditory discrimination as it relates to language acquisition, especially English as a second language. The first study investigated the influence of improving the signal-to-noise ratio on the differentiation of English phonemes. The results showed better differentiation with better signal-to-noise ratio. The second studied speech perception in noise by young adults for whom English was a second language. The outcome indicated that the second language learners required a better signal-to-noise ratio to perform equally to the native language participants. The last study surveyed the acoustic conditions of preschool and day care classrooms, wherein first and second language learning occurs. The survey suggested an unfavorable acoustic environment for language learning. 10. Acoustic Spatiality Brandon LaBelle 2012-06-01 Full Text Available Experiences of listening can be appreciated as intensely relational, bringing us into contact with surrounding events, bodies and things. Given that sound propagates and expands outwardly, as a set of oscillations from a particular source, listening carries with it a sensual intensity, whereby auditory phenomena deliver intrusive and disruptive as well as soothing and assuring experiences. The physicality characteristic of sound suggests a deeply impressionistic, locational "knowledge structure" – that is, the ways in which listening affords processes of exchange, of being in the world, and from which we extend ourselves. Sound, as physical energy reflecting and absorbing into the materiality around us, and even one's self, provides a rich platform for understanding place and emplacement. Sound is always already a trace of location.Such features of auditory experience give suggestion for what I may call an acoustical paradigm – how sound sets in motion not only the material world but also the flows of the imagination, lending to forces of signification and social structure, and figuring us in relation to each other. The relationality of sound brings us into a steady web of interferences, each of which announces the promise or problematic of being somewhere. 11. Acoustic Neurinomas Mohammad Faraji Rad 2011-01-01 Full Text Available Acoustic neuromas (AN are schwann cell-derived tumors that commonly arise from the vestibular portion of the eighth cranial nerve also known as vestibular schwannoma(VS causes unilateral hearing loss, tinnitus, vertigo and unsteadiness. In many cases, the tumor size may remain unchanged for many years following diagnosis, which is typically made by MRI. In the majority of cases the tumor is small, leaving the clinician and patient with the options of either serial scanning or active treatment by gamma knife radiosurgery (GKR or microneurosurgery. Despite the vast number of published treatment reports, comparative studies are few. The predominant clinical endpoints of AN treatment include tumor control, facial nerve function and hearing preservation. Less focus has been put on symptom relief and health-related quality of life (QOL. It is uncertain if treating a small tumor leaves the patient with a better chance of obtaining relief from future hearing loss, vertigo or tinnitus than by observing it without treatment. In this paper we review the literature for the natural course, the treatment alternatives and the results of AN. Finally, we present our experience with a management strategy applied for more than 30 years. 12. 电网不平衡下MMC多变量保护控制器参数设计研究%Design and Analysis of Control Parameter for Multi-variable Flexible Control in MMC Under Unbalanced AC Grid Conditions 朱明琳; 杭丽君; 李国杰; 解大; 李文伟 2016-01-01 电网不平衡不仅会导致模块化多电平变流器(multi-modular converter，MMC)网侧电流波形质量变差，还会引起桥臂电压不平衡、桥臂环流增加等一系列问题。为避免MMC系统发生过电压或过电流的安全问题，考虑交流侧最大工作电流、桥臂最大电容电压纹波以及最大注入无功三个方面的工作条件限制，分别从理论角度推导出多变量保护控制算法下控制参数k的计算公式。首先分析了MMC系统电流方程、电压方程以及能量的动态方程。基于上述系统方程，考虑MMC系统允许的工作范围如交流侧最大工作电流、桥臂最大电容电压纹波以及最大注入无功三个方面，详细给出了参数 k 的设计原则和流程。最后，利用实时仿真平台和MMC样机对理论计算给出了仿真和实验验证结果。%In the grid-connected modular multilevel converters (MMCs) system, grid faults not only cause the quality deterioration of grid currentswhich may lead the MMC to shut down, but also bring unbalanced problems to the arm voltages. In this paper, a multi-variable protected control method which was employed ind-q coordinate was presented. Considering the permitted maximum of three-phase current, the permitted capacitor voltage ripple and the maximum reactive power set-point, the calculation of the parameterk was given respectively. The converter mathematical models which were based on the laws of Kirchhoff and energy balance were given first. Then the relationship between the system requirements, such as the maximum current and the permitted capacitor voltage ripple, and the parameterk was derived. Furthermore, the design principles of parameterk were deduced. Finally, the simulating results from real time digital simulator (RTDS), and the experimental results from a scaled-down MMC prototype were presented to verify the theoretical analysis. 13. Acoustic source for generating an acoustic beam Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian 2016-05-31 An acoustic source for generating an acoustic beam includes a housing; a plurality of spaced apart piezo-electric layers disposed within the housing; and a non-linear medium filling between the plurality of layers. Each of the plurality of piezoelectric layers is configured to generate an acoustic wave. The non-linear medium and the plurality of piezo-electric material layers have a matching impedance so as to enhance a transmission of the acoustic wave generated by each of plurality of layers through the remaining plurality of layers. 14. Canonical Acoustics and Its Application to Surface Acoustic Wave on Acoustic Metamaterials Shen, Jian Qi 2016-08-01 In a conventional formalism of acoustics, acoustic pressure p and velocity field u are used for characterizing acoustic waves propagating inside elastic/acoustic materials. We shall treat some fundamental problems relevant to acoustic wave propagation alternatively by using canonical acoustics (a more concise and compact formalism of acoustic dynamics), in which an acoustic scalar potential and an acoustic vector potential (Φ ,V), instead of the conventional acoustic field quantities such as acoustic pressure and velocity field (p,u) for characterizing acoustic waves, have been defined as the fundamental variables. The canonical formalism of the acoustic energy-momentum tensor is derived in terms of the acoustic potentials. Both the acoustic Hamiltonian density and the acoustic Lagrangian density have been defined, and based on this formulation, the acoustic wave quantization in a fluid is also developed. Such a formalism of acoustic potentials is employed to the problem of negative-mass-density assisted surface acoustic wave that is a highly localized surface bound state (an eigenstate of the acoustic wave equations). Since such a surface acoustic wave can be strongly confined to an interface between an acoustic metamaterial (e.g., fluid-solid composite structures with a negative dynamical mass density) and an ordinary material (with a positive mass density), it will give rise to an effect of acoustic field enhancement on the acoustic interface, and would have potential applications in acoustic device design for acoustic wave control. 15. An architecture for implementation of multivariable controllers Niemann, Hans Henrik; Stoustrup, Jakob 1999-01-01 august 2002 Abstract An architecture for implementation of multivariable controllers is presented in this paper. The architecture is based on the Youla-Jabr-Bongiorno-Kucera parameterization of all stabilizing controllers. By using this architecture for implementation of multivariable controllers... 16. A kernel version of multivariate alteration detection Nielsen, Allan Aasbjerg; Vestergaard, Jacob Schack 2013-01-01 Based on the established methods kernel canonical correlation analysis and multivariate alteration detection we introduce a kernel version of multivariate alteration detection. A case study with SPOT HRV data shows that the kMAD variates focus on extreme change observations.......Based on the established methods kernel canonical correlation analysis and multivariate alteration detection we introduce a kernel version of multivariate alteration detection. A case study with SPOT HRV data shows that the kMAD variates focus on extreme change observations.... 17. Multivariate normal-Laplace distribution and processes Kanichukattu Korakutty Jose 2014-12-01 Full Text Available The normal-Laplace distribution is considered and its properties are discussed. A multivariate normal-Laplace distribution is introduced and its properties are studied. First order autoregressive processes with these stationary marginal distributions are developed and studied. A generalized multivariate normal-Laplace distribution is introduced. Multivariate geometric normal-Laplace distribution and multivariate geometric generalized normal-Laplace distributions are introduced and their properties are studied. Estimation of parameters and some applications are also discussed. 18. Sonification of acoustic emission data Raith, Manuel; Große, Christian 2014-05-01 While loading different specimens, acoustic emissions appear due to micro crack formation or friction of already existing crack edges. These acoustic emissions can be recorded using suitable ultrasonic transducers and transient recorders. The analysis of acoustic emissions can be used to investigate the mechanical behavior of different specimens under load. Our working group has undertaken several experiments, monitored with acoustic emission techniques. Different materials such as natural stone, concrete, wood, steel, carbon composites and bone were investigated. Also the experimental setup has been varied. Fire-spalling experiments on ultrahigh performance concrete and pullout experiments on bonded anchors have been carried out. Furthermore uniaxial compression tests on natural stone and animal bone had been conducted. The analysis tools include not only the counting of events but the analysis of full waveforms. Powerful localization algorithms and automatic onset picking techniques (based on Akaikes Information Criterion) were established to handle the huge amount of data. Up to several thousand events were recorded during experiments of a few minutes. More sophisticated techniques like moment tensor inversion have been established on this relatively small scale as well. Problems are related to the amount of data but also to signal-to-noise quality, boundary conditions (reflections) sensor characteristics and unknown and changing Greens functions of the media. Some of the acoustic emissions recorded during these experiments had been transferred into audio range. The transformation into the audio range was done using Matlab. It is the aim of the sonification to establish a tool that is on one hand able to help controlling the experiment in-situ and probably adjust the load parameters according to the number and intensity of the acoustic emissions. On the other hand sonification can help to improve the understanding of acoustic emission techniques for training 19. Multivariate strategies in functional magnetic resonance imaging Hansen, Lars Kai 2007-01-01 We discuss aspects of multivariate fMRI modeling, including the statistical evaluation of multivariate models and means for dimensional reduction. In a case study we analyze linear and non-linear dimensional reduction tools in the context of a mind reading' predictive multivariate fMRI model.... 20. An integrated multivariable artificial pancreas control system. Turksoy, Kamuran; Quinn, Lauretta T; Littlejohn, Elizabeth; Cinar, Ali 2014-05-01 The objective was to develop a closed-loop (CL) artificial pancreas (AP) control system that uses continuous measurements of glucose concentration and physiological variables, integrated with a hypoglycemia early alarm module to regulate glucose concentration and prevent hypoglycemia. Eleven open-loop (OL) and 9 CL experiments were performed. A multivariable adaptive artificial pancreas (MAAP) system was used for the first 6 CL experiments. An integrated multivariable adaptive artificial pancreas (IMAAP) system consisting of MAAP augmented with a hypoglycemia early alarm system was used during the last 3 CL experiments. Glucose values and physical activity information were measured and transferred to the controller every 10 minutes and insulin suggestions were entered to the pump manually. All experiments were designed to be close to real-life conditions. Severe hypoglycemic episodes were seen several times during the OL experiments. With the MAAP system, the occurrence of severe hypoglycemia was decreased significantly (P < .01). No hypoglycemia was seen with the IMAAP system. There was also a significant difference (P < .01) between OL and CL experiments with regard to percentage of glucose concentration (54% vs 58%) that remained within target range (70-180 mg/dl). Integration of an adaptive control and hypoglycemia early alarm system was able to keep glucose concentration values in target range in patients with type 1 diabetes. Postprandial hypoglycemia and exercise-induced hypoglycemia did not occur when this system was used. Physical activity information improved estimation of the blood glucose concentration and effectiveness of the control system. 1. Exploratory and multivariate data analysis Jambu, Michel 1991-01-01 With a useful index of notations at the beginning, this book explains and illustrates the theory and application of data analysis methods from univariate to multidimensional and how to learn and use them efficiently. This book is well illustrated and is a useful and well-documented review of the most important data analysis techniques.Key Features* Describes, in detail, exploratory data analysis techniques from the univariate to the multivariate ones* Features a complete description of correspondence analysis and factor analysis techniques as multidimensional statistical data a 2. Essentials of multivariate data analysis Spencer, Neil H 2013-01-01 ""… this text provides an overview at an introductory level of several methods in multivariate data analysis. It contains in-depth examples from one data set woven throughout the text, and a free [Excel] Add-In to perform the analyses in Excel, with step-by-step instructions provided for each technique. … could be used as a text (possibly supplemental) for courses in other fields where researchers wish to apply these methods without delving too deeply into the underlying statistics.""-The American Statistician, February 2015 3. Multivariate approaches in plant science Gottlieb, D.M.; Schultz, j.; Bruun, Susanne Wrang 2004-01-01 The objective of proteomics is to get an overview of the proteins expressed at a given point in time in a given tissue and to identify the connection to the biochemical status of that tissue. Therefore sample throughput and analysis time are important issues in proteomics. The concept of proteomics....... Traditionally statistical methods are not suitable for analysis of the huge amounts of data, where the number of variables exceed the number of objects. Multivariate data analysis, on the other hand, may uncover the hidden structures present in these data. This study takes its starting point in the field... 4. Aspects of multivariate statistical theory Muirhead, Robb J 2009-01-01 The Wiley-Interscience Paperback Series consists of selected books that have been made more accessible to consumers in an effort to increase global appeal and general circulation. With these new unabridged softcover volumes, Wiley hopes to extend the lives of these works by making them available to future generations of statisticians, mathematicians, and scientists. "". . . the wealth of material on statistics concerning the multivariate normal distribution is quite exceptional. As such it is a very useful source of information for the general statistician and a must for anyone wanting to pen 5. Simulation of multivariate diffusion bridges Bladt, Mogens; Finch, Samuel; Sørensen, Michael We propose simple methods for multivariate diffusion bridge simulation, which plays a fundamental role in simulation-based likelihood and Bayesian inference for stochastic differential equations. By a novel application of classical coupling methods, the new approach generalizes a previously...... proposed simulation method for one-dimensional bridges to the mulit-variate setting. First a method of simulating approzimate, but often very accurate, diffusion bridges is proposed. These approximate bridges are used as proposal for easily implementable MCMC algorithms that produce exact diffusion bridges... 6. Likelihood estimators for multivariate extremes Huser, Raphaël 2015-11-17 The main approach to inference for multivariate extremes consists in approximating the joint upper tail of the observations by a parametric family arising in the limit for extreme events. The latter may be expressed in terms of componentwise maxima, high threshold exceedances or point processes, yielding different but related asymptotic characterizations and estimators. The present paper clarifies the connections between the main likelihood estimators, and assesses their practical performance. We investigate their ability to estimate the extremal dependence structure and to predict future extremes, using exact calculations and simulation, in the case of the logistic model. 7. Atlantic Herring Acoustic Surveys National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Advanced Sampling Technologies Research Group conducts annual fisheries acoustic surveys using state-of-the-art acoustic, midwater trawling, and underwater... 8. Multivariate image analysis in biomedicine. Nattkemper, Tim W 2004-10-01 In recent years, multivariate imaging techniques are developed and applied in biomedical research in an increasing degree. In research projects and in clinical studies as well m-dimensional multivariate images (MVI) are recorded and stored to databases for a subsequent analysis. The complexity of the m-dimensional data and the growing number of high throughput applications call for new strategies for the application of image processing and data mining to support the direct interactive analysis by human experts. This article provides an overview of proposed approaches for MVI analysis in biomedicine. After summarizing the biomedical MVI techniques the two level framework for MVI analysis is illustrated. Following this framework, the state-of-the-art solutions from the fields of image processing and data mining are reviewed and discussed. Motivations for MVI data mining in biology and medicine are characterized, followed by an overview of graphical and auditory approaches for interactive data exploration. The paper concludes with summarizing open problems in MVI analysis and remarks upon the future development of biomedical MVI analysis. 9. Acoustic Communications (ACOMMS) ATD 2016-06-14 develop and demonstrate emerging undersea acoustic communication technologies at operationally useful ranges and data rates. The secondary objective...Technology Demonstration program (ACOMMS ATD) was to demonstrate long range and moderate data rate underwater acoustic communications between a submarine...moderate data rate acoustic communications capability for tactical use between submarines, surface combatants, unmanned undersea vehicles (UUVs), and other 10. Tutorial on architectural acoustics Shaw, Neil; Talaske, Rick; Bistafa, Sylvio 2002-11-01 This tutorial is intended to provide an overview of current knowledge and practice in architectural acoustics. Topics covered will include basic concepts and history, acoustics of small rooms (small rooms for speech such as classrooms and meeting rooms, music studios, small critical listening spaces such as home theatres) and the acoustics of large rooms (larger assembly halls, auditoria, and performance halls). 11. Modelling classroom conditions with different boundary conditions Marbjerg, Gerd Høy; Jeong, Cheol-Ho; Brunskog, Jonas; 2014-01-01 both specular and diffuse reflections with complex-valued acoustical descriptions of the surfaces. In this paper the PARISM model is used to simulate a rectangular room with most of the absorption located in the ceiling. This room configuration is typical for classroom conditions. The simulations......A model that combines image source modelling and acoustical radiosity with complex boundary condition, thus including phase shifts on reflection has been developed. The model is called PARISM (Phased Acoustical Radiosity and Image Source Model). It has been developed in order to be able to model...... are done using different boundary conditions in order to investigate the influence of phase shifts in reflections, the angle dependence of the reflection coefficient and the scattering coefficient. The focus of the simulations is to investigate the influence of the boundary condition on room acoustic... 12. Multivariate refinement equation with nonnegative masks 2006-01-01 This paper is concerned with multivariate refinement equations of the type ψ = ∑α∈Zs a(α)ψ(Mx - α),where ψ is the unknown function defined on the s-dimensional Euclidean space Rs, a is a finitely supported nonnegative sequence on Zs, and M is an s × s dilation matrix with m := |detM|. We characterize the existence of L2-solution of refinement equation in terms of spectral radius of a certain finite matrix or transition operator associated with refinement mask a and dilation matrix M. For s = 1 and M = 2, the sufficient and necessary conditions are obtained to characterize the existence of continuous solution of this refinement equation. 13. An Adaptive Multivariable Control System for Hydroelectric Generating Units Gunne J. Hegglid 1983-04-01 Full Text Available This paper describes an adaptive multivariable control system for hydroelectric generating units. The system is based on a detailed mathematical model of the synchronous generator, the water turbine, the exiter system and turbine control servo. The models of the water penstock and the connected power system are static. These assumptions are not considered crucial. The system uses a Kalman filter for optimal estimation of the state variables and the parameters of the electric grid equivalent. The multivariable control law is computed from a Riccatti equation and is made adaptive to the generators running condition by means of a least square technique. 14. Multivariate variance targeting in the BEKK-GARCH model Pedersen, Rasmus S.; Rahbæk, Anders 2014-01-01 This paper considers asymptotic inference in the multivariate BEKK model based on (co-)variance targeting (VT). By definition the VT estimator is a two-step estimator and the theory presented is based on expansions of the modified likelihood function, or estimating function, corresponding...... to these two steps. Strong consis-tency is established under weak moment conditions, while sixth-order moment restrictions are imposed to establish asymptotic normality. Included simulations indicate that the multivariately induced higher-order moment constraints are necessary... 15. Acoustic elliptical cylindrical cloaks Ma Hua; Qu Shao-Bo; Xu Zhuo; Wang Jia-Fu 2009-01-01 By making a comparison between the acoustic equations and the 2-dimensional (2D) Maxwell equations, we obtain the material parameter equations (MPE) for acoustic elliptical cylindrical cloaks. Both the theoretical results and the numerical results indicate that an elliptical cylindrical cloak can realize perfect acoustic invisibility when the spatial distributions of mass density and bulk modulus are exactly configured according to the proposed equations. The present work is the meaningful exploration of designing acoustic cloaks that are neither sphere nor circular cylinder in shape, and opens up possibilities for making complex and multiplex acoustic cloaks with simple models such as spheres, circular or elliptic cylinders. 16. Observability of multivariate differential embeddings Aguirre, Luis Antonio [Laboratorio de Modelagem, Analise e Controle de Sistemas Nao Lineares, Departamento de Engenharia Eletronica, Universidade Federeal de Minas Gerais, Av. Antonio Carlos 6627, 31270-901 Belo Horizonte, MG (Brazil); Letellier, Christophe [Universite de Rouen-CORIA UMR 6614, Av. de l' Universite, BP 12, F-76801 Saint-Etienne du Rouvray Cedex (France) 2005-07-15 The present paper extends some results recently developed for the analysis of observability in nonlinear dynamical systems. The aim of the paper is to address the problem of embedding an attractor using more than one observable. A multivariate nonlinear observability matrix is proposed which includes the monovariable nonlinear and linear observability matrices as particular cases. Using the developed framework and a number of worked examples, it is shown that the choice of embedding coordinates is critical. Moreover, in some cases, to reconstruct the dynamics using more than one observable could be worse than to reconstruct using a scalar measurement. Finally, using the developed framework it is shown that increasing the embedding dimension, observability problems diminish and can even be eliminated. This seems to be a physically meaningful interpretation of the Takens embedding theorem. 17. Multivariate Analyis of Swap Bribery Dorn, Britta 2010-01-01 We consider the computational complexity of a problem modeling bribery in the context of voting systems. In the scenario of Swap Bribery, each voter assigns a certain price for swapping the positions of two consecutive candidates in his preference ranking. The question is whether it is possible, without exceeding a given budget, to bribe the voters in a way that the preferred candidate wins in the election. We initiate a parameterized and multivariate complexity analysis of Swap Bribery, focusing on the case of k-approval. We investigate how different cost functions affect the computational complexity of the problem. We identify a special case of k-approval for which the problem can be solved in polynomial time, whereas we prove NP-hardness for a slightly more general scenario. We obtain fixed-parameter tractability as well as W[1]-hardness results for certain natural parameters. 18. Multivariate Variance Targeting in the BEKK-GARCH Model Pedersen, Rasmus Søndergaard; Rahbek, Anders This paper considers asymptotic inference in the multivariate BEKK model based on (co-)variance targeting (VT). By de…nition the VT estimator is a two-step estimator and the theory presented is based on expansions of the modi…ed likelihood function, or estimating function, corresponding to these ......This paper considers asymptotic inference in the multivariate BEKK model based on (co-)variance targeting (VT). By de…nition the VT estimator is a two-step estimator and the theory presented is based on expansions of the modi…ed likelihood function, or estimating function, corresponding...... to these two steps. Strong consistency is established under weak moment conditions, while sixth order moment restrictions are imposed to establish asymptotic normality. Included simulations indicate that the multivariately induced higher-order moment constraints are indeed necessary.... 19. Canada Basin Acoustic Propagation Experiment (CANAPE) 2015-09-30 pworcester@ucsd.edu Award Number: N00014-15-1-2068 LONG-TERM GOALS The Arctic Ocean is undergoing dramatic changes in both the ice cover and...fundamental limits to the use of acoustic methods and signal processing imposed by ice and ocean processes in the new Arctic . The hope is that these...the ocean from wind and solar forcing and preserving the stable Arctic acoustic channel. Ice conditions are not the only environmental changes in 20. MTCI acoustic agglomeration particulate control Chandran, R.R.; Mansour, M.N. [Manufacturing and Technology Conversion International, Inc., Columbia, MD (United States); Scaroni, A.W.; Koopmann, G.H. [Pennsylvania State Univ., University Park, PA (United States); Loth, J.L. [West Virginia Univ., Morgantown, WV (United States) 1994-10-01 The overall objective of this project is to demonstrate pulse combination induced acoustic enhancement of coal ash agglomeration and sulfur capture at conditions typical of direct coal-fired turbines and PFBC hot gas cleanup. MTCI has developed an advanced compact pulse combustor island for direct coal-firing in combustion gas turbines. This combustor island comprises a coal-fired pulse combustor, a combined ash agglomeration and sulfur capture chamber (CAASCC), and a hot cyclone. In the MTCI proprietary approach, the pulse combustion-induced high intensity sound waves improve sulfur capture efficiency and ash agglomeration. The resulting agglomerates allow the use of commercial cyclones and achieve very high particulate collection efficiency. In the MTCI proprietary approach, sorbent particles are injected into a gas stream subjected to an intense acoustic field. The acoustic field serves to improve sulfur capture efficiency by enhancing both gas film and intra-particle mass transfer rates. In addition, the sorbent particles act as dynamic filter foci, providing a high density of stagnant agglomerating centers for trapping the finer entrained (in the oscillating flow field) fly ash fractions. A team has been formed with MTCI as the prime contractor and Penn State University and West Virginia University as subcontractors to MTCI. MTCI is focusing on hardware development and system demonstration, PSU is investigating and modeling acoustic agglomeration and sulfur capture, and WVU is studying aerovalve fluid dynamics. Results are presented from all three studies. 1. Acoustic modes in fluid networks Michalopoulos, C. D.; Clark, Robert W., Jr.; Doiron, Harold H. Pressure and flow rate eigenvalue problems for one-dimensional flow of a fluid in a network of pipes are derived from the familiar transmission line equations. These equations are linearized by assuming small velocity and pressure oscillations about mean flow conditions. It is shown that the flow rate eigenvalues are the same as the pressure eigenvalues and the relationship between line pressure modes and flow rate modes is established. A volume at the end of each branch is employed which allows any combination of boundary conditions, from open to closed, to be used. The Jacobi iterative method is used to compute undamped natural frequencies and associated pressure/flow modes. Several numerical examples are presented which include acoustic modes for the Helium Supply System of the Space Shuttle Orbiter Main Propulsion System. It should be noted that the method presented herein can be applied to any one-dimensional acoustic system involving an arbitrary number of branches. 2. Common predictor effects for multivariate longitudinal data Jia, Juan; Weiss, Robert E. 2009-01-01 Multivariate outcomes measured longitudinally over time are common in medicine, public health, psychology and sociology. The typical (saturated) longitudinal multivariate regression model has a separate set of regression coefficients for each outcome. However, multivariate outcomes are often quite similar and many outcomes can be expected to respond similarly to changes in covariate values. Given a set of outcomes likely to share common covariate effects, we propose the Clustered Outcome COmm... 3. 运用声发射技术监测金属塑性成型过程中润滑状态的研究%Study on the Lubricating Condition for Metal Plastic Deformation with Acoustic Emission Technique 贾园; 张守茁; 席镇; 高宏; 魏盛春; 孟维 2009-01-01 The acoustic emission (AE) technique was used in the experiment to monitor the lubricating condition in the metal plastic deformation. The AE signals of the frietion between the metal and the AE signals of the metal plastic deforma-tion were studied by monitoring the metal plastic deformation process and the friction process in the condition of lubricating or without lubricant. The results show that the AE signals generated by the different materials are unequal in the numerical value. The friction AE signals are less than the plastic deformation AE signals for the same materials. The AE technique could be used to monitor the lubricating condition in the course of the metal plastic deformation by the real time waveshape or mean value of the AE parameters.%为监测金属塑性成型过程中的润滑状态,采用运用声发射技术,通过对无润滑和有润滑时金属塑性变形过程和摩擦过程的监测及对比,分别研究了金属摩擦声发射信号和塑性变形声发射信号.结果表明,不同材料摩擦产生的声发射信号数值上大小不同,同种材料摩擦声发射信号数值上小于塑性变形声发射信号;采用声发射技术,基于实时波形和声发射信号参数的平均值都能监测金属塑性成型时的润滑状态. 4. Lake bed classification using acoustic data Yin, Karen K.; Li, Xing; Bonde, John; Richards, Carl; Cholwek, Gary 1998-01-01 As part of our effort to identify the lake bed surficial substrates using remote sensing data, this work designs pattern classifiers by multivariate statistical methods. Probability distribution of the preprocessed acoustic signal is analyzed first. A confidence region approach is then adopted to improve the design of the existing classifier. A technique for further isolation is proposed which minimizes the expected loss from misclassification. The devices constructed are applicable for real-time lake bed categorization. A mimimax approach is suggested to treat more general cases where the a priori probability distribution of the substrate types is unknown. Comparison of the suggested methods with the traditional likelihood ratio tests is discussed. 5. Detrended fluctuation analysis of multivariate time series Xiong, Hui; Shang, P. 2017-01-01 In this work, we generalize the detrended fluctuation analysis (DFA) to the multivariate case, named multivariate DFA (MVDFA). The validity of the proposed MVDFA is illustrated by numerical simulations on synthetic multivariate processes, where the cases that initial data are generated independently from the same system and from different systems as well as the correlated variate from one system are considered. Moreover, the proposed MVDFA works well when applied to the multi-scale analysis of the returns of stock indices in Chinese and US stock markets. Generally, connections between the multivariate system and the individual variate are uncovered, showing the solid performances of MVDFA and the multi-scale MVDFA. 6. On the Security of Multivariate Hash Functions LUO Yi-yuan; LAI Xue-jia 2009-01-01 Multivariate hash functions are a type of hash functions whose compression function is explicitly defined as a sequence of multivariate equations. Billet et al designed the hash function MQ-HASH and Ding et al proposed a similar construction. In this paper, we analyze the security of multivariate hash functions and conclude that low degree multivariate functions such as MQ-HASH are neither pseudo-random nor unpredictable. There may be trivial collisions and fixed point attacks if the parameters of the compression ftmction have been chosen. And they are also not computation-resistance, which makes MAC forgery easily. 7. Multivariate correction in laser-enhanced ionization with laser sampling Popov, A. M.; Labutin, T. A.; Sychev, D. N.; Gorbatenko, A. A.; Zorov, N. B. 2007-03-01 The opportunity of normalizing laser-enhanced ionization (LEI) signals by several reference signals (RS) measured simultaneously has been examined in view of correcting variations of laser parameters and matrix interferences. Opto-acoustic, atomic emission and non-selective ionization signals and their paired combination were used as RS for Li determination in aluminum alloys (0-6% Mg, 0-5% Cu, 0-1% Sc, 0-1% Ag). The specific normalization procedure in case of RS essential multicollinearity has been proposed. LEI and RS for each definite ablation pulse energy were plotted in Cartesian co-ordinates ( x and y axes — the RS values, z axis — LEI signal). It was found that in the three-dimensional space the slope of the correlation line to the plane of RS depends on the analyte content in the solid sample. The use of this slope has therefore been proposed as a multivariate corrected analytical signal. Multivariate correlative normalization provides analytical signal free of matrix interferences for Al-Mg-Cu-Li alloys. The application of this novel approach to the determination of Li allows plotting unified calibration curves for Al-alloys of different matrix composition. 8. Multivariate correction in laser-enhanced ionization with laser sampling Popov, A.M. [Department of Chemistry, M. V. Lomonosov Moscow State University, 119992 Russia Moscow GSP-2, Leninskie Gory 1 build.3 (Russian Federation); Labutin, T.A. [Department of Chemistry, M. V. Lomonosov Moscow State University, 119992 Russia Moscow GSP-2, Leninskie Gory 1 build.3 (Russian Federation)], E-mail: timurla@laser.chem.msu.ru; Sychev, D.N.; Gorbatenko, A.A.; Zorov, N.B. [Department of Chemistry, M. V. Lomonosov Moscow State University, 119992 Russia Moscow GSP-2, Leninskie Gory 1 build.3 (Russian Federation) 2007-03-15 The opportunity of normalizing laser-enhanced ionization (LEI) signals by several reference signals (RS) measured simultaneously has been examined in view of correcting variations of laser parameters and matrix interferences. Opto-acoustic, atomic emission and non-selective ionization signals and their paired combination were used as RS for Li determination in aluminum alloys (0-6% Mg, 0-5% Cu, 0-1% Sc, 0-1% Ag). The specific normalization procedure in case of RS essential multicollinearity has been proposed. LEI and RS for each definite ablation pulse energy were plotted in Cartesian co-ordinates (x and y axes - the RS values, z axis - LEI signal). It was found that in the three-dimensional space the slope of the correlation line to the plane of RS depends on the analyte content in the solid sample. The use of this slope has therefore been proposed as a multivariate corrected analytical signal. Multivariate correlative normalization provides analytical signal free of matrix interferences for Al-Mg-Cu-Li alloys. The application of this novel approach to the determination of Li allows plotting unified calibration curves for Al-alloys of different matrix composition. 9. Acoustic Logging Modeling by Refined Biot's Equations Plyushchenkov, Boris D.; Turchaninov, Victor I. An explicit uniform completely conservative finite difference scheme for the refined Biot's equations is proposed. This system is modified according to the modern theory of dynamic permeability and tortuosity in a fluid-saturated elastic porous media. The approximate local boundary transparency conditions are constructed. The acoustic logging device is simulated by the choice of appropriate boundary conditions on its external surface. This scheme and these conditions are satisfactory for exploring borehole acoustic problems in permeable formations in a real axial-symmetrical situation. The developed approach can be adapted for a nonsymmetric case also. 10. Vibro-acoustics Nilsson, Anders 2015-01-01 This three-volume book gives a thorough and comprehensive presentation of vibration and acoustic theories. Different from traditional textbooks which typically deal with some aspects of either acoustic or vibration problems, it is unique of this book to combine those two correlated subjects together. Moreover, it provides fundamental analysis and mathematical descriptions for several crucial phenomena of Vibro-Acoustics which are quite useful in noise reduction, including how structures are excited, energy flows from an excitation point to a sound radiating surface, and finally how a structure radiates noise to a surrounding fluid. Many measurement results included in the text make the reading interesting and informative. Problems/questions are listed at the end of each chapter and the solutions are provided. This will help the readers to understand the topics of Vibro-Acoustics more deeply. The book should be of interest to anyone interested in sound and vibration, vehicle acoustics, ship acoustics and inter... 11. Springer handbook of acoustics 2014-01-01 Acoustics, the science of sound, has developed into a broad interdisciplinary field encompassing the academic disciplines of physics, engineering, psychology, speech, audiology, music, architecture, physiology, neuroscience, and electronics. The Springer Handbook of Acoustics is also in his 2nd edition an unparalleled modern handbook reflecting this richly interdisciplinary nature edited by one of the acknowledged masters in the field, Thomas Rossing. Researchers and students benefit from the comprehensive contents. This new edition of the Handbook features over 11 revised and expanded chapters, new illustrations, and 2 new chapters covering microphone arrays and acoustic emission. Updated chapters contain the latest research and applications in, e.g. sound propagation in the atmosphere, nonlinear acoustics in fluids, building and concert hall acoustics, signal processing, psychoacoustics, computer music, animal bioacousics, sound intensity, modal acoustics as well as new chapters on microphone arrays an... 12. APPLICATION OF DOMAIN DECOMPOSITION IN ACOUSTIC AND STRUCTURAL ACOUSTIC ANALYSIS 2007-01-01 Conventional element based methods for modeling acoustic problems are limited to low-frequency applications due to the huge computational efforts. For high-frequency applications, probabilistic techniques, such as statistical energy analysis (SEA), are used. For mid-frequency range, currently no adequate and mature simulation methods exist. Recently, wave based method has been developed which is based on the indirect TREFFTZ approach and has shown to be able to tackle problems in the mid-frequency range. In contrast with the element based methods, no discretization is required. A sufficient, but not necessary, condition for convergence of this method is that the acoustic problem domain is convex. Non-convex domains have to be partitioned into a number of (convex) subdomains. At the interfaces between subdomains, specific coupling conditions have to be imposed. The considered two-dimensional coupled vibro-acoustic problem illustrates the beneficial convergence rate of the proposed wave based prediction technique with high accuracy. The results show the new technique can be applied up to much higher frequencies. 13. [The acoustic indicator of saliva under stress]. Shalenkova, M A; Mikhaĭlova, Z D; Klemin, V A; Korkotashvili, L V; Abanin, A M; Klemina, A V; Dolgov, V V 2014-03-01 The situation of stress affects various organs and systems that results in development of functional disorders and/or somatic diseases. As a result, different noninvasive, including salivary, techniques of diagnostic of stress conditions are in the process of development. The dynamics of acoustic indicator of saliva is studied during the period of passing the exams. The relationship of indicator with levels of potassium, sodium, glucose and protein of saliva was analyzed. The sampling consisted of 102 students of 5 and 6 academic years of medical university. To detect the acoustic indicator of saliva acoustic analyzer AKBa-01- "BIOM" was applied. The level of potassium and sodium in saliva was detected using method of flame photometry. The level of glucose in saliva was detected by glucose oxydase technique using analyzer "EXAN-G". The protein in saliva was detected by biuretic technique. The correlation between acoustic indicator of saliva and analyzed indicators of saliva was established. 14. Finite difference solutions to shocked acoustic waves Walkington, N. J.; Eversman, W. 1983-01-01 The MacCormack, Lambda and split flux finite differencing schemes are used to solve a one dimensional acoustics problem. Two duct configurations were considered, a uniform duct and a converging-diverging nozzle. Asymptotic solutions for these two ducts are compared with the numerical solutions. When the acoustic amplitude and frequency are sufficiently high the acoustic signal shocks. This condition leads to a deterioration of the numerical solutions since viscous terms may be required if the shock is to be resolved. A continuous uniform duct solution is considered to demonstrate how the viscous terms modify the solution. These results are then compared with a shocked solution with and without viscous terms. Generally it is found that the most accurate solutions are those obtained using the minimum possible viscosity coefficients. All of the schemes considered give results accurate enough for acoustic power calculations with no one scheme performing significantly better than the others. 15. Deep Water Ocean Acoustics 2016-04-30 OASIS, INC. 1 Report No. QSR-14C0172-Ocean Acoustics-043016 Quarterly Progress Report Technical and Financial Deep Water Ocean Acoustics...understanding of the impact of the ocean and seafloor environmental variability on deep- water (long-range) ocean acoustic propagation and to...improve our understanding. During the past few years, the physics effects studied have been three-dimensional propagation on global scales, deep water 16. Nearfield Acoustical Holography Hayek, Sabih I. Nearfield acoustical holography (NAH) is a method by which a set of acoustic pressure measurements at points located on a specific surface (called a hologram) can be used to image sources on vibrating surfaces on the acoustic field in three-dimensional space. NAH data are processed to take advantage of the evanescent wavefield to image sources that are separated less that one-eighth of a wavelength. 17. Laboratory for Structural Acoustics Federal Laboratory Consortium — FUNCTION: Supports experimental research where acoustic radiation, scattering, and surface vibration measurements of fluid-loaded and non-fluid-loaded structures are... 18. Handbook of Engineering Acoustics Möser, Michael 2013-01-01 This book examines the physical background of engineering acoustics, focusing on empirically obtained engineering experience as well as on measurement techniques and engineering methods for prognostics. Its goal is not only to describe the state of art of engineering acoustics but also to give practical help to engineers in order to solve acoustic problems. It deals with the origin, the transmission and the methods of the abating different kinds of air-borne and structure-borne sounds caused by various mechanisms – from traffic to machinery and flow-induced sound. In addition the modern aspects of room and building acoustics, as well as psychoacoustics and active noise control, are covered. 19. Acoustic Technology Laboratory Federal Laboratory Consortium — This laboratory contains an electro-magnetic worldwide data collection and field measurement capability in the area of acoustic technology. Outfitted by NASA Langley... 20. Localized acoustic surface modes Farhat, Mohamed; Chen, Pai-Yen; Bağcı, Hakan 2016-04-01 We introduce the concept of localized acoustic surface modes. We demonstrate that they are induced on a two-dimensional cylindrical rigid surface with subwavelength corrugations under excitation by an incident acoustic plane wave. Our results show that the corrugated rigid surface is acoustically equivalent to a cylindrical scatterer with uniform mass density that can be represented using a Drude-like model. This, indeed, suggests that plasmonic-like acoustic materials can be engineered with potential applications in various areas including sensing, imaging, and cloaking. 1. Shallow Water Acoustic Laboratory Federal Laboratory Consortium — FUNCTION: Supports experimental research where high-frequency acoustic scattering and surface vibration measurements of fluid-loaded and non-fluid-loaded structures... 2. Localized Acoustic Surface Modes Farhat, Mohamed 2015-08-04 We introduce the concept of localized acoustic surface modes (ASMs). We demonstrate that they are induced on a two-dimensional cylindrical rigid surface with subwavelength corrugations under excitation by an incident acoustic plane wave. Our results show that the corrugated rigid surface is acoustically equivalent to a cylindrical scatterer with uniform mass density that can be represented using a Drude-like model. This, indeed, suggests that plasmonic-like acoustic materials can be engineered with potential applications in various areas including sensing, imaging, and cloaking. 3. Acoustic Signals and Systems 2008-01-01 The Handbook of Signal Processing in Acoustics will compile the techniques and applications of signal processing as they are used in the many varied areas of Acoustics. The Handbook will emphasize the interdisciplinary nature of signal processing in acoustics. Each Section of the Handbook...... will present topics on signal processing which are important in a specific area of acoustics. These will be of interest to specialists in these areas because they will be presented from their technical perspective, rather than a generic engineering approach to signal processing. Non-specialists, or specialists... 4. Measuring equilibrium models: a multivariate approach Nadji RAHMANIA 2011-04-01 Full Text Available This paper presents a multivariate methodology for obtaining measures of unobserved macroeconomic variables. The used procedure is the multivariate Hodrick-Prescot which depends on smoothing param eters. The choice of these parameters is crucial. Our approach is based on consistent estimators of these parameters, depending only on the observed data. 5. Multivariate interval-censored survival data Hougaard, Philip 2014-01-01 , derived from the L and R points. Asymptotic results are simple for the former and complicated for the latter. This paper is a review describing the extension to multivariate data, like eruption times for teeth examined at visits to the dentist. Parametric models extend easily to multivariate data. However... 6. An Implementation Technique for Multivariate Robust Design MA Yi-zhong; ZHAO Feng-yu 2005-01-01 This paper investigates systematically the problem of multivariate robust parameter design. First, a measurement criterion for the total variation of multivariate quality characteristics is introduced by the result of information theory. Then the implementation procedure in the robust design is presented. After that, a simulation example from a practical industrial process is provided. Finally, some comments and further work are discussed. 7. Multivariate pluvial flood damage models Van Ootegem, Luc [HIVA — University of Louvain (Belgium); SHERPPA — Ghent University (Belgium); Verhofstadt, Elsy [SHERPPA — Ghent University (Belgium); Van Herck, Kristine; Creten, Tom [HIVA — University of Louvain (Belgium) 2015-09-15 Depth–damage-functions, relating the monetary flood damage to the depth of the inundation, are commonly used in the case of fluvial floods (floods caused by a river overflowing). We construct four multivariate damage models for pluvial floods (caused by extreme rainfall) by differentiating on the one hand between ground floor floods and basement floods and on the other hand between damage to residential buildings and damage to housing contents. We do not only take into account the effect of flood-depth on damage, but also incorporate the effects of non-hazard indicators (building characteristics, behavioural indicators and socio-economic variables). By using a Tobit-estimation technique on identified victims of pluvial floods in Flanders (Belgium), we take into account the effect of cases of reported zero damage. Our results show that the flood depth is an important predictor of damage, but with a diverging impact between ground floor floods and basement floods. Also non-hazard indicators are important. For example being aware of the risk just before the water enters the building reduces content damage considerably, underlining the importance of warning systems and policy in this case of pluvial floods. - Highlights: • Prediction of damage of pluvial floods using also non-hazard information • We include ‘no damage cases’ using a Tobit model. • The damage of flood depth is stronger for ground floor than for basement floods. • Non-hazard indicators are especially important for content damage. • Potential gain of policies that increase awareness of flood risks. 8. Multivariate Analysis of Ladle Vibration Yenus, Jaefer; Brooks, Geoffrey; Dunn, Michelle 2016-08-01 The homogeneity of composition and uniformity of temperature of the steel melt before it is transferred to the tundish are crucial in making high-quality steel product. The homogenization process is performed by stirring the melt using inert gas in ladles. Continuous monitoring of this process is important to make sure the action of stirring is constant throughout the ladle. Currently, the stirring process is monitored by process operators who largely rely on visual and acoustic phenomena from the ladle. However, due to lack of measurable signals, the accuracy and suitability of this manual monitoring are problematic. The actual flow of argon gas to the ladle may not be same as the flow gage reading due to leakage along the gas line components. As a result, the actual degree of stirring may not be correctly known. Various researchers have used one-dimensional vibration, and sound and image signals measured from the ladle to predict the degree of stirring inside. They developed online sensors which are indeed to monitor the online stirring phenomena. In this investigation, triaxial vibration signals have been measured from a cold water model which is a model of an industrial ladle. Three flow rate ranges and varying bath heights were used to collect vibration signals. The Fast Fourier Transform was applied to the dataset before it has been analyzed using principal component analysis (PCA) and partial least squares (PLS). PCA was used to unveil the structure in the experimental data. PLS was mainly applied to predict the stirring from the vibration response. It was found that for each flow rate range considered in this study, the informative signals reside in different frequency ranges. The first latent variables in these frequency ranges explain more than 95 pct of the variation in the stirring process for the entire single layer and the double layer data collected from the cold model. PLS analysis in these identified frequency ranges demonstrated that the latent 9. Multivariate Term Structure Models with Level and Heteroskedasticity Effects Christiansen, Charlotte 2005-01-01 The paper introduces and estimates a multivariate level-GARCH model for the long rate and the term-structure spread where the conditional volatility is proportional to the ãth power of the variable itself (level effects) and the conditional covariance matrix evolves according to a multivariate...... GARCH process (heteroskedasticity effects). The long-rate variance exhibits heteroskedasticity effects and level effects in accordance with the square-root model. The spread variance exhibits heteroskedasticity effects but no level effects. The level-GARCH model is preferred above the GARCH model...... and the level model. GARCH effects are more important than level effects. The results are robust to the maturity of the interest rates. Udgivelsesdato: MAY... 10. Multivariate Receptor Models for Spatially Correlated Multipollutant Data Jun, Mikyoung 2013-08-01 The goal of multivariate receptor modeling is to estimate the profiles of major pollution sources and quantify their impacts based on ambient measurements of pollutants. Traditionally, multivariate receptor modeling has been applied to multiple air pollutant data measured at a single monitoring site or measurements of a single pollutant collected at multiple monitoring sites. Despite the growing availability of multipollutant data collected from multiple monitoring sites, there has not yet been any attempt to incorporate spatial dependence that may exist in such data into multivariate receptor modeling. We propose a spatial statistics extension of multivariate receptor models that enables us to incorporate spatial dependence into estimation of source composition profiles and contributions given the prespecified number of sources and the model identification conditions. The proposed method yields more precise estimates of source profiles by accounting for spatial dependence in the estimation. More importantly, it enables predictions of source contributions at unmonitored sites as well as when there are missing values at monitoring sites. The method is illustrated with simulated data and real multipollutant data collected from eight monitoring sites in Harris County, Texas. Supplementary materials for this article, including data and R code for implementing the methods, are available online on the journal web site. © 2013 Copyright Taylor and Francis Group, LLC. 11. Potential of acoustic emissions from three point bending tests as rock failure precursors Agioutantis Z.; Kaklis K.; Mavrigiannakis S.; Verigakis M.; Vallianatos F.; Saltas V. 2016-01-01 Development of failure in brittle materials is associated with microcracks, which release energy in the form of elastic waves called acoustic emissions. This paper presents results from acoustic emission mea-surements obtained during three point bending tests on Nestos marble under laboratory conditions. Acoustic emission activity was monitored using piezoelectric acoustic emission sensors, and the potential for accurate prediction of rock damage based on acoustic emission data was investigated. Damage local-ization was determined based on acoustic emissions generated from the critically stressed region as scat-tered events at stresses below and close to the strength of the material. 12. Acoustic fluidization for earthquakes? Sornette, D.; Sornette, A. 2000-01-01 Melosh [1996] has suggested that acoustic fluidization could provide an alternative to theories that are invoked as explanations for why some crustal faults appear to be weak. We show that there is a subtle but profound inconsistency in the theory that unfortunately invalidates the results. We propose possible remedies but must acknowledge that the relevance of acoustic fluidization remains an open question. 13. Sensitive acoustic vibration sensor using single-mode fiber tapers. Li, Yi; Wang, Xiaozhen; Bao, Xiaoyi 2011-05-01 Optical fiber sensors are a good alternative to piezoelectric devices in electromagnetic sensitive environments. In this study, we reported a fiber acoustic sensor based on single-mode fiber (SMF) tapers. The fiber taper is used as the sensing arm in a Mach-Zehnder interferometer. Benefiting from their micrometer dimensions, fiber tapers have shown higher sensitivities to the acoustic vibrations than SMFs. Under the same conditions, the thinnest fiber taper in this report, with a diameter of 1.7 µm, shows a 20 dB improvement in the signal to noise ratio as compared to that of an SMF. This acoustic vibration sensor can detect the acoustic waves over the frequencies of 30 Hz-40 kHz, which is limited by the acoustic wave generator in experiments. We also discussed the phase changes of fiber tapers with different diameters under acoustic vibrations. 14. Multivariate normative comparisons using an aggregated database Murre, Jaap M. J.; Huizenga, Hilde M. 2017-01-01 In multivariate normative comparisons, a patient’s profile of test scores is compared to those in a normative sample. Recently, it has been shown that these multivariate normative comparisons enhance the sensitivity of neuropsychological assessment. However, multivariate normative comparisons require multivariate normative data, which are often unavailable. In this paper, we show how a multivariate normative database can be constructed by combining healthy control group data from published neuropsychological studies. We show that three issues should be addressed to construct a multivariate normative database. First, the database may have a multilevel structure, with participants nested within studies. Second, not all tests are administered in every study, so many data may be missing. Third, a patient should be compared to controls of similar age, gender and educational background rather than to the entire normative sample. To address these issues, we propose a multilevel approach for multivariate normative comparisons that accounts for missing data and includes covariates for age, gender and educational background. Simulations show that this approach controls the number of false positives and has high sensitivity to detect genuine deviations from the norm. An empirical example is provided. Implications for other domains than neuropsychology are also discussed. To facilitate broader adoption of these methods, we provide code implementing the entire analysis in the open source software package R. PMID:28267796 15. Acoustic ground impedance meter Zuckerwar, A. J. (Inventor) 1984-01-01 A method and apparatus are presented for measuring the acoustic impedance of a surface in which the surface is used to enclose one end of the chamber of a Helmholz resonator. Acoustic waves are generated in the neck of the resonator by a piston driven by a variable speed motor through a cam assembly. The acoustic waves are measured in the chamber and the frequency of the generated acoustic waves is measured by an optical device. These measurements are used to compute the compliance and conductance of the chamber and surface combined. The same procedure is followed with a calibration plate having infinite acoustic impedance enclosing the chamber of the resonator to compute the compliance and conductance of the chamber alone. Then by subtracting, the compliance and conductance for the surface is obtained. 16. Cochlear bionic acoustic metamaterials Ma, Fuyin; Wu, Jiu Hui; Huang, Meng; Fu, Gang; Bai, Changan 2014-11-01 A design of bionic acoustic metamaterial and acoustic functional devices was proposed by employing the mammalian cochlear as a prototype. First, combined with the experimental data in previous literatures, it is pointed out that the cochlear hair cells and stereocilia cluster are a kind of natural biological acoustic metamaterials with the negative stiffness characteristics. Then, to design the acoustic functional devices conveniently in engineering application, a simplified parametric helical structure was proposed to replace actual irregular cochlea for bionic design, and based on the computational results of such a bionic parametric helical structure, it is suggested that the overall cochlear is a local resonant system with the negative dynamic effective mass characteristics. There are many potential applications in the bandboard energy recovery device, cochlear implant, and acoustic black hole. 17. Computational Ocean Acoustics Jensen, Finn B; Porter, Michael B; Schmidt, Henrik 2011-01-01 Since the mid-1970s, the computer has played an increasingly pivotal role in the field of ocean acoustics. Faster and less expensive than actual ocean experiments, and capable of accommodating the full complexity of the acoustic problem, numerical models are now standard research tools in ocean laboratories. The progress made in computational ocean acoustics over the last thirty years is summed up in this authoritative and innovatively illustrated new text. Written by some of the field's pioneers, all Fellows of the Acoustical Society of America, Computational Ocean Acoustics presents the latest numerical techniques for solving the wave equation in heterogeneous fluid–solid media. The authors discuss various computational schemes in detail, emphasizing the importance of theoretical foundations that lead directly to numerical implementations for real ocean environments. To further clarify the presentation, the fundamental propagation features of the techniques are illustrated in color. Computational Ocean A... 18. Ocean acoustic reverberation tomography. Dunn, Robert A 2015-12-01 Seismic wide-angle imaging using ship-towed acoustic sources and networks of ocean bottom seismographs is a common technique for exploring earth structure beneath the oceans. In these studies, the recorded data are dominated by acoustic waves propagating as reverberations in the water column. For surveys with a small receiver spacing (e.g., ocean acoustic reverberation tomography, is developed that uses the travel times of direct and reflected waves to image ocean acoustic structure. Reverberation tomography offers an alternative approach for determining the structure of the oceans and advancing the understanding of ocean heat content and mixing processes. The technique has the potential for revealing small-scale ocean thermal structure over the entire vertical height of the water column and along long survey profiles or across three-dimensional volumes of the ocean. For realistic experimental geometries and data noise levels, the method can produce images of ocean sound speed on a smaller scale than traditional acoustic tomography. 19. Acoustic fluidization - A new geologic process Melosh, H. J. 1979-01-01 A number of geologic processes, particularly seismic faulting, impact crater slumping, and long runout landslides, require the failure of geologic materials under differential stresses much smaller than expected on the basis of conventional rock mechanics. This paper proposes that the low strengths apparent in these phenomena are due to a state of 'acoustic fluidization' induced by a transient strong acoustic wave field. The strain rates possible in such a field are evaluated, and it is shown that acoustically fluidized debris behaves as a newtonian fluid with a viscosity in the range 100,000 to 10,000,000 P for plausible conditions. Energy gains and losses in the acoustic field are discussed, and the mechanism is shown to be effective if internal dissipation in the field gives a Q approximately greater than 100. Whether such values for Q are realized is not known at present. However, acoustic fluidization provides a qualitatively correct description of the failure of rock debris under low differential stresses in the processes of faulting, crater slumping, and long runout landslides. Acoustic fluidization thus deserves serious consideration as a possible explanation of these phenomena. 20. Multivariate statistical methods a first course Marcoulides, George A 2014-01-01 Multivariate statistics refer to an assortment of statistical methods that have been developed to handle situations in which multiple variables or measures are involved. Any analysis of more than two variables or measures can loosely be considered a multivariate statistical analysis. An introductory text for students learning multivariate statistical methods for the first time, this book keeps mathematical details to a minimum while conveying the basic principles. One of the principal strategies used throughout the book--in addition to the presentation of actual data analyses--is poin 1. Acoustic monitoring systems tests at Indian Point Unit 1. Final report Smith, J.R.; Rao, G.V.; Craig, J. 1979-12-01 This report describes the results of a program to test acoustic monitoring systems on Indian Point Unit No. 1 under actual plant operating conditions, less the reactor core. The two types of systems evaluated were the monitoring of acoustic emissions generated by growing flaws and the monitoring of acoustic signals from leaks. 2. Flat acoustic lens by acoustic grating with curled slits Peng, Pai; Xiao, Bingmu; Wu, Ying, E-mail: ying.wu@kaust.edu.sa 2014-10-03 We design a flat sub-wavelength lens that can focus acoustic wave. We analytically study the transmission through an acoustic grating with curled slits, which can serve as a material with tunable impedance and refractive index for acoustic waves. The effective parameters rely on the geometry of the slits and are independent of frequency. A flat acoustic focusing lens by such acoustic grating with gradient effective refractive index is designed. The focusing effect is clearly observed in simulations and well predicted by the theory. We demonstrate that despite the large impedance mismatch between the acoustic lens and the matrix, the intensity at the focal point is still high due to Fabry–Perot resonance. - Highlights: • Expression of transmission coefficient of an acoustic grating with curled slits. • Non-dispersive and tunable effective medium parameters for the acoustic grating. • A flat acoustic focusing lens with gradient index by using the acoustic grating. 3. Flow acoustics in solid-fluid structures Willatzen, Morten; Mads, Mikhail Vladimirovich Deryabin 2008-01-01 The governing two-dimensional equations of a heterogeneous material composed of a fluid (allowed to flow in the absence of acoustic excitations) and a crystalline piezoelectric cubic solid stacked one-dimensionally (along the z direction) are derived and special emphasis is given to the discussion...... of acoustic group velocity for the structure as a function of the wavenumber component perpendicular to the stacking direction (being the x axis). Variations in physical parameters with y are neglected assuming infinite material homogeneity along the y direction and the flow velocity is assumed to be directed...... in the general solution but examples are provided for the case where these are subject to rigid-wall conditions (Neumann boundary conditions in the acoustic pressure). In the second part of the paper, emphasis is given to the general case of larger frequencies and wavenumber-frequency bandstructure formation... 4. Utilizing computer models for optimizing classroom acoustics Hinckley, Jennifer M.; Rosenberg, Carl J. 2002-05-01 The acoustical conditions in a classroom play an integral role in establishing an ideal learning environment. Speech intelligibility is dependent on many factors, including speech loudness, room finishes, and background noise levels. The goal of this investigation was to use computer modeling techniques to study the effect of acoustical conditions on speech intelligibility in a classroom. This study focused on a simulated classroom which was generated using the CATT-acoustic computer modeling program. The computer was utilized as an analytical tool in an effort to optimize speech intelligibility in a typical classroom environment. The factors that were focused on were reverberation time, location of absorptive materials, and background noise levels. Speech intelligibility was measured with the Rapid Speech Transmission Index (RASTI) method. 5. The value of multivariate model sophistication Rombouts, Jeroen; Stentoft, Lars; Violante, Francesco 2014-01-01 We assess the predictive accuracies of a large number of multivariate volatility models in terms of pricing options on the Dow Jones Industrial Average. We measure the value of model sophistication in terms of dollar losses by considering a set of 444 multivariate models that differ in their spec......We assess the predictive accuracies of a large number of multivariate volatility models in terms of pricing options on the Dow Jones Industrial Average. We measure the value of model sophistication in terms of dollar losses by considering a set of 444 multivariate models that differ...... of correlation models, we propose a new model that allows for correlation spillovers without too many parameters. This model performs about 60% better than the existing correlation models we consider. Relaxing a Gaussian innovation for a Laplace innovation assumption improves the pricing in a more minor way... 6. An Introduction to Applied Multivariate Analysis Raykov, Tenko 2008-01-01 Focuses on the core multivariate statistics topics which are of fundamental relevance for its understanding. This book emphasis on the topics that are critical to those in the behavioral, social, and educational sciences. 7. Multivariate analysis of industrial scale fermentation data Mears, Lisa; Nørregård, Rasmus; Stocks, Stuart; , and thereforeareas offocus for optimising the processoperation.This requires multivariate methods which canutilise the complexdatasetswhich areroutinely collected, containing online measured variables and offline sample data.Fermentation processes are highly sensitive to operational changes, as well as between... 8. Predicting Acoustics in Class Rooms Christensen, Claus Lynge; Rindel, Jens Holger 2005-01-01 Typical class rooms have fairly simple geometries, even so room acoustics in this type of room is difficult to predict using today's room acoustic computer modeling software. The reasons why acoustics of class rooms are harder to predict than acoustics of complicated concert halls might... 9. Underwater Applications of Acoustical Holography P. C. Mehta 1984-01-01 Full Text Available The paper describes the basic technique of acoustical holography. Requirements for recording the acoustical hologram are discussed with its ability for underwater imaging in view. Some practical systems for short-range and medium-range imaging are described. The advantages of acoustical holography over optical imaging, acoustical imaging and sonars are outlined. 10. Acoustic mapping velocimetry Muste, M.; Baranya, S.; Tsubaki, R.; Kim, D.; Ho, H.; Tsai, H.; Law, D. 2016-05-01 Knowledge of sediment dynamics in rivers is of great importance for various practical purposes. Despite its high relevance in riverine environment processes, the monitoring of sediment rates remains a major and challenging task for both suspended and bed load estimation. While the measurement of suspended load is currently an active area of testing with nonintrusive technologies (optical and acoustic), bed load measurement does not mark a similar progress. This paper describes an innovative combination of measurement techniques and analysis protocols that establishes the proof-of-concept for a promising technique, labeled herein Acoustic Mapping Velocimetry (AMV). The technique estimates bed load rates in rivers developing bed forms using a nonintrusive measurements approach. The raw information for AMV is collected with acoustic multibeam technology that in turn provides maps of the bathymetry over longitudinal swaths. As long as the acoustic maps can be acquired relatively quickly and the repetition rate for the mapping is commensurate with the movement of the bed forms, successive acoustic maps capture the progression of the bed form movement. Two-dimensional velocity maps associated with the bed form migration are obtained by implementing algorithms typically used in particle image velocimetry to acoustic maps converted in gray-level images. Furthermore, use of the obtained acoustic and velocity maps in conjunction with analytical formulations (e.g., Exner equation) enables estimation of multidirectional bed load rates over the whole imaged area. This paper presents a validation study of the AMV technique using a set of laboratory experiments. 11. Identification of Acoustic-Vibratory System by Acoustic Measurement Takuzo Iwatsubo 1996-01-01 Full Text Available A new method for reducing ill-conditioning in a class of identification problems is proposed. The key point of the method is that the identified vibration of the sound source is expressed as a superposition of vibration modes. The mathematical property of the coefficient matrix, the practical error expanding ratio, and the stochastic error expanding ratio are investigated in a numerical example. The mode-superposition method is shown to be an effective tool for acoustic-vibratory inverse analysis. 12. Multivariable Feedback Control of Nuclear Reactors Rune Moen 1982-07-01 Full Text Available Multivariable feedback control has been adapted for optimal control of the spatial power distribution in nuclear reactor cores. Two design techniques, based on the theory of automatic control, were developed: the State Variable Feedback (SVF is an application of the linear optimal control theory, and the Multivariable Frequency Response (MFR is based on a generalization of the traditional frequency response approach to control system design. 13. Multivariate Longitudinal Analysis with Bivariate Correlation Test Adjakossa, Eric Houngla; Sadissou, Ibrahim; Hounkonnou, Mahouton Norbert; Nuel, Gregory 2016-01-01 In the context of multivariate multilevel data analysis, this paper focuses on the multivariate linear mixed-effects model, including all the correlations between the random effects when the dimensional residual terms are assumed uncorrelated. Using the EM algorithm, we suggest more general expressions of the model’s parameters estimators. These estimators can be used in the framework of the multivariate longitudinal data analysis as well as in the more general context of the analysis of multivariate multilevel data. By using a likelihood ratio test, we test the significance of the correlations between the random effects of two dependent variables of the model, in order to investigate whether or not it is useful to model these dependent variables jointly. Simulation studies are done to assess both the parameter recovery performance of the EM estimators and the power of the test. Using two empirical data sets which are of longitudinal multivariate type and multivariate multilevel type, respectively, the usefulness of the test is illustrated. PMID:27537692 14. On Modeling Eavesdropping Attacks in Underwater Acoustic Sensor Networks † Wang, Qiu; Dai, Hong-Ning; Li, Xuran; Wang, Hao; Xiao, Hong 2016-01-01 The security and privacy of underwater acoustic sensor networks has received extensive attention recently due to the proliferation of underwater activities. This paper proposes an analytical model to investigate the eavesdropping attacks in underwater acoustic sensor networks. Our analytical framework considers the impacts of various underwater acoustic channel conditions (such as the acoustic signal frequency, spreading factor and wind speed) and different hydrophones (isotropic hydrophones and array hydrophones) in terms of network nodes and eavesdroppers. We also conduct extensive simulations to evaluate the effectiveness and the accuracy of our proposed model. Empirical results show that our proposed model is quite accurate. In addition, our results also imply that the eavesdropping probability heavily depends on both the underwater acoustic channel conditions and the features of hydrophones. PMID:27213379 15. On Modeling Eavesdropping Attacks in Underwater Acoustic Sensor Networks. Wang, Qiu; Dai, Hong-Ning; Li, Xuran; Wang, Hao; Xiao, Hong 2016-01-01 The security and privacy of underwater acoustic sensor networks has received extensive attention recently due to the proliferation of underwater activities. This paper proposes an analytical model to investigate the eavesdropping attacks in underwater acoustic sensor networks. Our analytical framework considers the impacts of various underwater acoustic channel conditions (such as the acoustic signal frequency, spreading factor and wind speed) and different hydrophones (isotropic hydrophones and array hydrophones) in terms of network nodes and eavesdroppers. We also conduct extensive simulations to evaluate the effectiveness and the accuracy of our proposed model. Empirical results show that our proposed model is quite accurate. In addition, our results also imply that the eavesdropping probability heavily depends on both the underwater acoustic channel conditions and the features of hydrophones. 16. On Modeling Eavesdropping Attacks in Underwater Acoustic Sensor Networks Qiu Wang 2016-05-01 Full Text Available The security and privacy of underwater acoustic sensor networks has received extensive attention recently due to the proliferation of underwater activities. This paper proposes an analytical model to investigate the eavesdropping attacks in underwater acoustic sensor networks. Our analytical framework considers the impacts of various underwater acoustic channel conditions (such as the acoustic signal frequency, spreading factor and wind speed and different hydrophones (isotropic hydrophones and array hydrophones in terms of network nodes and eavesdroppers. We also conduct extensive simulations to evaluate the effectiveness and the accuracy of our proposed model. Empirical results show that our proposed model is quite accurate. In addition, our results also imply that the eavesdropping probability heavily depends on both the underwater acoustic channel conditions and the features of hydrophones. 17. Computational analysis of acoustic transmission through periodically perforated interfaces Rohan E. 2009-06-01 Full Text Available The objective of the paper is to demonstrate the homogenization approach applied to modelling the acoustic transmission on perforated interfaces embedded in the acoustic fluid. We assume a layer, with periodically perforated obstacles, separating two half-spaces filled with the fluid. The homogenization method provides limit transmission conditions which can be prescribed at the homogenized surface representing the "limit" interface. The conditions describe relationship between jump of the acoustic pressures and the transversal acoustic velocity, on introducing the "in-layer pressure" which describes wave propagation in the tangent directions with respect to the interface.This approach may serve as a relevant tool for optimal design of devices aimed at attenuation of the acoustic waves, such as the engine exhaust mufflers or other structures fitted with sieves and grillages. We present numerical examples of wave propagation in a muffler-like structure illustrating viability of the approach when complex 3D geometries of the interface perforation are considered. 18. Application of Gauge Theory to Acoustic Fields -- Revolutionizing and Rewriting the Whole Field of Acoustics Gan, W. S. 2008-12-01 This paper is to be dedicated to Prof C N Yang's 85th birthday celebration because the idea here was inspired by Prof Yang's public lecture in Singapore in 2006. There are many similarities between electromagnetic waves and acoustic waves. Maxwell's equations for em waves is the oldest gauge theory. We discover symmetries in the pair of wave equations in the acoustic stress field and the velocity field. We also derive a new equation in terms of the stress field for sound propagation in solids. This is different from the Christoffel's equation which is in term of the velocity field. We feel that stress field can better characterize the elastic properties of the sound waves. We also derive the acoustic gauge field condition and gauge invariance and symmetries for the acoustic fields. We also apply symmetries to study negative refraction. Note from Publisher: This article contains the abstract only. 19. Signal analysis of acoustic and flow-induced vibrations of BWR main steam line Espinosa-Paredes, G., E-mail: gepe@xanum.uam.mx [División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, México, D.F. 09340 (Mexico); Prieto-Guerrero, A. [División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, México, D.F. 09340 (Mexico); Núñez-Carrera, A. [Comisión Nacional de Seguridad Nuclear y Salvaguardias, Doctor Barragán 779, Col. Narvarte, México, D.F. 03020 (Mexico); Vázquez-Rodríguez, A. [División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, México, D.F. 09340 (Mexico); Centeno-Pérez, J. [Instituto Politécnico Nacional, Escuela Superior de Física y Matemáticas Unidad Profesional “Adolfo López Mateos”, Av. IPN, s/n, México, D.F. 07738 (Mexico); Espinosa-Martínez, E.-G. [Departamento de Sistemas Energéticos, Universidad Nacional Autónoma de México, México, D.F. 04510 (Mexico); and others 2016-05-15 Highlights: • Acoustic and flow-induced vibrations of BWR are analyzed. • BWR performance after extended power uprate is considered. • Effect of acoustic side branches (ASB) is analyzed. • The ASB represents a reduction in the acoustic loads to the steam dryer. • Methodology developed for simultaneous analyzing the signals in the MSL. - Abstract: The aim of this work is the signal analysis of acoustic waves due to phenomenon known as singing in Safety Relief Valves (SRV) of the main steam lines (MSL) in a typical BWR5. The acoustic resonance in SRV standpipes and fluctuating pressure is propagated from SRV to the dryer through the MSL. The signals are analyzed with a novel method based on the Multivariate Empirical Mode Decomposition (M-EMD). The M-EMD algorithm has the potential to find common oscillatory modes (IMF) within multivariate data. Based on this fact, we implement the M-EMD technique to find the oscillatory mode in BWR considering the measurements obtained collected by the strain gauges located around the MSL. These IMF, analyzed simultaneously in time, allow obtaining an estimation of the effects of the multiple-SRV in the MSL. Two scenarios are analyzed: the first is the signal obtained before the installation of the acoustic dampers (ASB), and the second, the signal obtained after installation. The results show the effectiveness of the ASB to damp the strong resonances when the steam flow increases, which represents an important reduction in the acoustic loads to the steam dryer. 20. Multivariate return periods of sea storms for coastal erosion risk assessment S. Corbella 2012-08-01 Full Text Available The erosion of a beach depends on various storm characteristics. Ideally, the risk associated with a storm would be described by a single multivariate return period that is also representative of the erosion risk, i.e. a 100 yr multivariate storm return period would cause a 100 yr erosion return period. Unfortunately, a specific probability level may be associated with numerous combinations of storm characteristics. These combinations, despite having the same multivariate probability, may cause very different erosion outcomes. This paper explores this ambiguity problem in the context of copula based multivariate return periods and using a case study at Durban on the east coast of South Africa. Simulations were used to correlate multivariate return periods of historical events to return periods of estimated storm induced erosion volumes. In addition, the relationship of the most-likely design event (Salvadori et al., 2011 to coastal erosion was investigated. It was found that the multivariate return periods for wave height and duration had the highest correlation to erosion return periods. The most-likely design event was found to be an inadequate design method in its current form. We explore the inclusion of conditions based on the physical realizability of wave events and the use of multivariate linear regression to relate storm parameters to erosion computed from a process based model. Establishing a link between storm statistics and erosion consequences can resolve the ambiguity between multivariate storm return periods and associated erosion return periods. 1. Sonochemistry and the acoustic bubble Grieser, Franz; Enomoto, Naoya; Harada, Hisashi; Okitsu, Kenji; Yasui, Kyuichi 2015-01-01 Sonochemistry and the Acoustic Bubble provides an introduction to the way ultrasound acts on bubbles in a liquid to cause bubbles to collapse violently, leading to localized 'hot spots' in the liquid with temperatures of 5000° celcius and under pressures of several hundred atmospheres. These extreme conditions produce events such as the emission of light, sonoluminescence, with a lifetime of less than a nanosecond, and free radicals that can initiate a host of varied chemical reactions (sonochemistry) in the liquid, all at room temperature. The physics and chemistry behind the p 2. A Symplectic Method to Generate Multivariate Normal Distributions Baumgarten, Christian 2012-01-01 The AMAS group at the Paul Scherrer Institute developed an object oriented library for high performance simulation of high intensity ion beam transport with space charge. Such particle-in-cell (PIC) simulations require a method to generate multivariate particle distributions as starting conditions. In a preceeding publications it has been shown that the generators of symplectic transformations in two dimensions are a subset of the real Dirac matrices (RDMs) and that few symplectic transformations are required to transform a quadratic Hamiltonian into diagonal form. Here we argue that the use of RDMs is well suited for the generation of multivariate normal distributions with arbitrary covariances. A direct and simple argument supporting this claim is that this is the "natural" way how such distributions are formed. The transport of charged particle beams may serve as an example: An uncorrelated gaussian distribution of particles starting at some initial position of the accelerator is subject to linear deformat... 3. Regularized multivariate regression models with skew-t error distributions Chen, Lianfu 2014-06-01 We consider regularization of the parameters in multivariate linear regression models with the errors having a multivariate skew-t distribution. An iterative penalized likelihood procedure is proposed for constructing sparse estimators of both the regression coefficient and inverse scale matrices simultaneously. The sparsity is introduced through penalizing the negative log-likelihood by adding L1-penalties on the entries of the two matrices. Taking advantage of the hierarchical representation of skew-t distributions, and using the expectation conditional maximization (ECM) algorithm, we reduce the problem to penalized normal likelihood and develop a procedure to minimize the ensuing objective function. Using a simulation study the performance of the method is assessed, and the methodology is illustrated using a real data set with a 24-dimensional response vector. © 2014 Elsevier B.V. 4. Enhancing scientific reasoning by refining students' models of multivariable causality Keselman, Alla Inquiry learning as an educational method is gaining increasing support among elementary and middle school educators. In inquiry activities at the middle school level, students are typically asked to conduct investigations and infer causal relationships about multivariable causal systems. In these activities, students usually demonstrate significant strategic weaknesses and insufficient metastrategic understanding of task demands. Present work suggests that these weaknesses arise from students' deficient mental models of multivariable causality, in which effects of individual features are neither additive, nor constant. This study is an attempt to develop an intervention aimed at enhancing scientific reasoning by refining students' models of multivariable causality. Three groups of students engaged in a scientific investigation activity over seven weekly sessions. By creating unique combinations of five features potentially involved in earthquake mechanism and observing associated risk meter readings, students had to find out which of the features were causal, and to learn to predict earthquake risk. Additionally, students in the instructional and practice groups engaged in self-directed practice in making scientific predictions. The instructional group also participated in weekly instructional sessions on making predictions based on multivariable causality. Students in the practice and instructional conditions showed small to moderate improvement in their attention to the evidence and in their metastrategic ability to recognize effective investigative strategies in the work of other students. They also demonstrated a trend towards making a greater number of valid inferences than the control group students. Additionally, students in the instructional condition showed significant improvement in their ability to draw inferences based on multiple records. They also developed more accurate knowledge about non-causal features of the system. These gains were maintained 5. Acoustic Igniter Project National Aeronautics and Space Administration — An acoustic igniter eliminates the need to use electrical energy to drive spark systems to initiate combustion in liquid-propellant rockets. It does not involve the... 6. Acoustic imaging system Kendall, J. M., Jr. 1977-01-01 Tool detects noise sources by scanning sound "scene" and displaying relative location of noise-producing elements in area. System consists of ellipsoidal acoustic mirror and microphone and a display device. 7. Acoustic imaging system Smith, Richard W. 1979-01-01 An acoustic imaging system for displaying an object viewed by a moving array of transducers as the array is pivoted about a fixed point within a given plane. A plurality of transducers are fixedly positioned and equally spaced within a laterally extending array and operatively directed to transmit and receive acoustic signals along substantially parallel transmission paths. The transducers are sequentially activated along the array to transmit and receive acoustic signals according to a preestablished sequence. Means are provided for generating output voltages for each reception of an acoustic signal, corresponding to the coordinate position of the object viewed as the array is pivoted. Receptions from each of the transducers are presented on the same display at coordinates corresponding to the actual position of the object viewed to form a plane view of the object scanned. 8. An acoustic invisible gateway Zhu, Yi-Fan; Liang, Bin; Kan, Wei-Wei; Yang, Jun; Cheng, Jian-Chun 2015-01-01 The recently-emerged concept of "invisible gateway" with the extraordinary capability to block the waves but allow the passage of other entities has attracted great attentions due to the general interests in illusion devices. However, the possibility to realize such a fascinating phenomenon for acoustic waves has not yet been explored, which should be of paramount significance for acoustical applications but would necessarily involve experimental difficulty. Here we design and experimentally demonstrate an acoustic invisible gateway (AIG) capable of concealing a channel under the detection of sound. Instead of "restoring" a whole block of background medium by using transformation acoustics that inevitably requires complementary or restoring media with extreme parameters, we propose an inherently distinct methodology that only aims at engineering the surface impedance at the "gate" to mimic a rigid "wall" and can be conveniently implemented by decorating meta-structures behind the channel. Such a simple yet ef... 9. Acoustics Noise Test Cell Federal Laboratory Consortium — The Acoustic Noise Test Cell at the NASA/Caltech Jet Propulsion Laboratory (JPL) is located adjacent to the large vibration system; both are located in a class 10K... 10. Thermal Acoustic Fatigue Apparatus Federal Laboratory Consortium — The Thermal Acoustic Fatigue Apparatus (TAFA) is a progressive wave tube test facility that is used to test structures for dynamic response and sonic fatigue due to... 11. Autonomous Acoustic Receiver System Federal Laboratory Consortium — FUNCTION: Collects underwater acoustic data and oceanographic data. Data are recorded onboard an ocean buoy and can be telemetered to a remote ship or shore station... 12. Principles of musical acoustics Hartmann, William M 2013-01-01 Principles of Musical Acoustics focuses on the basic principles in the science and technology of music. Musical examples and specific musical instruments demonstrate the principles. The book begins with a study of vibrations and waves, in that order. These topics constitute the basic physical properties of sound, one of two pillars supporting the science of musical acoustics. The second pillar is the human element, the physiological and psychological aspects of acoustical science. The perceptual topics include loudness, pitch, tone color, and localization of sound. With these two pillars in place, it is possible to go in a variety of directions. The book treats in turn, the topics of room acoustics, audio both analog and digital, broadcasting, and speech. It ends with chapters on the traditional musical instruments, organized by family. The mathematical level of this book assumes that the reader is familiar with elementary algebra. Trigonometric functions, logarithms and powers also appear in the book, but co... 13. Symptoms of Acoustic Neuroma ... Programs & Services Search ANAUSA.org Connect with us! Symptoms of Acoustic Neuroma Each heading slides to reveal more information. Early Symptoms Early Symptoms Early symptoms are easily overlooked, thus making diagnosis ... 14. Anal acoustic reflectometry Mitchell, Peter J; Klarskov, Niels; Telford, Karen J; 2011-01-01 Anal acoustic reflectometry is a new technique of assessing anal sphincter function. Five new variables reflecting anal canal function are measured: the opening and closing pressure, the opening and closing elastance, and hysteresis.......Anal acoustic reflectometry is a new technique of assessing anal sphincter function. Five new variables reflecting anal canal function are measured: the opening and closing pressure, the opening and closing elastance, and hysteresis.... 15. eshless Method for Acoustic and Elastic Modeling JiaXiaofeng; HuTianyue; WangRunqiu 2005-01-01 Wave equation method is one of the fundamental techniques for seismic modeling and imaging. In this paper the element-free-method (EFM) was used to solve acoustic and elastic equations.The key point of this method is no need of elements, which makes nodes free from the elemental restraint. Besides, the moving-least-squares (MLS) criterion in EFM leads to a high accuracy and smooth derivatives. The theories of EFM for both acoustic and elastic wave equations as well as absorbing boundary conditions were discussed respectively. Furthermore, some pre-stack models were used to show the good performance of EFM in seismic modeling. 16. Multivariate log-skew-elliptical distributions with applications to precipitation data Marchenko, Yulia V. 2009-07-13 We introduce a family of multivariate log-skew-elliptical distributions, extending the list of multivariate distributions with positive support. We investigate their probabilistic properties such as stochastic representations, marginal and conditional distributions, and existence of moments, as well as inferential properties. We demonstrate, for example, that as for the log-t distribution, the positive moments of the log-skew-t distribution do not exist. Our emphasis is on two special cases, the log-skew-normal and log-skew-t distributions, which we use to analyze US national (univariate) and regional (multivariate) monthly precipitation data. © 2009 John Wiley & Sons, Ltd. 17. An operational modal analysis approach based on parametrically identified multivariable transmissibilities Devriendt, Christof; De Sitter, Gert; Guillaume, Patrick 2010-07-01 In this contribution the approach to identify modal parameters from output-only (scalar) transmissibility measurements [C. Devriendt, P. Guillaume, The use of transmissibility measurements in output-only modal analysis, Mechanical Systems and Signal Processing 21 (7) (2007) 2689-2696] is generalized to multivariable transmissibilities. In general, the poles that are identified from (scalar as well as multivariable) transmissibility measurements do not correspond with the system's poles. However, by combining transmissibility measurements under different loading conditions, it is shown in this paper how model parameters can be identified from multivariable transmissibility measurements. 18. Multivariate Statistical Modelling of Drought and Heat Wave Events Manning, Colin; Widmann, Martin; Vrac, Mathieu; Maraun, Douglas; Bevaqua, Emanuele 2016-04-01 Multivariate Statistical Modelling of Drought and Heat Wave Events C. Manning1,2, M. Widmann1, M. Vrac2, D. Maraun3, E. Bevaqua2,3 1. School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK 2. Laboratoire des Sciences du Climat et de l'Environnement, (LSCE-IPSL), Centre d'Etudes de Saclay, Gif-sur-Yvette, France 3. Wegener Center for Climate and Global Change, University of Graz, Brandhofgasse 5, 8010 Graz, Austria Compound extreme events are a combination of two or more contributing events which in themselves may not be extreme but through their joint occurrence produce an extreme impact. Compound events are noted in the latest IPCC report as an important type of extreme event that have been given little attention so far. As part of the CE:LLO project (Compound Events: muLtivariate statisticaL mOdelling) we are developing a multivariate statistical model to gain an understanding of the dependence structure of certain compound events. One focus of this project is on the interaction between drought and heat wave events. Soil moisture has both a local and non-local effect on the occurrence of heat waves where it strongly controls the latent heat flux affecting the transfer of sensible heat to the atmosphere. These processes can create a feedback whereby a heat wave maybe amplified or suppressed by the soil moisture preconditioning, and vice versa, the heat wave may in turn have an effect on soil conditions. An aim of this project is to capture this dependence in order to correctly describe the joint probabilities of these conditions and the resulting probability of their compound impact. We will show an application of Pair Copula Constructions (PCCs) to study the aforementioned compound event. PCCs allow in theory for the formulation of multivariate dependence structures in any dimension where the PCC is a decomposition of a multivariate distribution into a product of bivariate components modelled using copulas. A 19. 带吸收边界条件的声波方程显式差分格式的稳定性分析%STABILITY ANALYSIS OF EXPLICIT FINITE DIFFERENCE SCHEMES FOR THE ACOUSTIC WAVE EQUATION WITH ABSORBING BOUNDARY CONDITIONS 邵秀民; 刘臻 2001-01-01 It is well known that in numerical computations of wave equationsby utiliz ing explicit schemes the stability is an extremely important problem when artifi cial boundaries are introduced and absorbing boundary conditions are imposed on them. In this paper, the stability of finite difference schemes for the acoustic wave equation with the first-and the second-order Clayton-Engquist-Majda absorbing boundary conditions is discussed by using energy techniques. The corresponding stability conditions (i.e., the stability bounds of the CFL number) are given, which is sharper than those stability conditions for interior schemes or other kinds of boundary conditions. Numerical results are presented to confirm the correctness of the theoretical analysis. 20. Giant Magnetostrictive Material Loudspeaker System Acoustic Radiation Simulation WANG Rui; ZHANG Yong-fa 2008-01-01 An infinite panel model of giant magnetostrictive material loudspeaker system (GMMLS) is proposed by making use of finite element method(FEM). Bending wave eigenfunction is introduced to describe the acoustic radiation condition of the panel. Far-field response in different conditions is calculated by changing the mass surface density. Conclusion is obtained by analyzing the curves simulated, that panel which has larger mass surface density can hardly generate far-field acoustic radiation for lower frequency, while the panel has smaller mass surface density generates far-field acoustic radiation for lower frequency evenly and stronger. 1. Acoustic vector sensor signal processing SUN Guiqing; LI Qihu; ZHANG Bin 2006-01-01 Acoustic vector sensor simultaneously, colocately and directly measures orthogonal components of particle velocity as well as pressure at single point in acoustic field so that is possible to improve performance of traditional underwater acoustic measurement devices or detection systems and extends new ideas for solving practical underwater acoustic engineering problems. Although acoustic vector sensor history of appearing in underwater acoustic area is no long, but with huge and potential military demands, acoustic vector sensor has strong development trend in last decade, it is evolving into a one of important underwater acoustic technology. Under this background, we try to review recent progress in study on acoustic vector sensor signal processing, such as signal detection, DOA estimation, beamforming, and so on. 2. Multivariate quality control of lubricating oils using Fourier transform infrared spectroscopy Borin,Alessandra; Poppi, Ronei Jesus 2004-01-01 Multivariate quality control in conjunction with Fourier transform infrared Spectroscopy (FTIR) were used to qualitatively detect the class and the condition of lubricating oils. The multivariate approach was based on principal component analysis (PCA), first to classify the lubricating oil type (mineral, synthetic and semi-synthetic) and then to develop two control charts: a T² chart using the most significant principal components and a Q chart with the PC not used in the first chart. From t... 3. Schmidt decomposition and multivariate statistical analysis Bogdanov, Yu. I.; Bogdanova, N. A.; Fastovets, D. V.; Luckichev, V. F. 2016-12-01 The new method of multivariate data analysis based on the complements of classical probability distribution to quantum state and Schmidt decomposition is presented. We considered Schmidt formalism application to problems of statistical correlation analysis. Correlation of photons in the beam splitter output channels, when input photons statistics is given by compound Poisson distribution is examined. The developed formalism allows us to analyze multidimensional systems and we have obtained analytical formulas for Schmidt decomposition of multivariate Gaussian states. It is shown that mathematical tools of quantum mechanics can significantly improve the classical statistical analysis. The presented formalism is the natural approach for the analysis of both classical and quantum multivariate systems and can be applied in various tasks associated with research of dependences. 4. A MULTIVARIATE ANALYSIS OF CROATIAN COUNTIES ENTREPRENEURSHIP Elza Jurun 2012-12-01 Full Text Available In the focus of this paper is a multivariate analysis of Croatian Counties entrepreneurship. Complete data base available by official statistic institutions at national and regional level is used. Modern econometric methodology starting from a comparative analysis via multiple regression to multivariate cluster analysis is carried out as well as the analysis of successful or inefficacious entrepreneurship measured by indicators of efficiency, profitability and productivity. Time horizons of the comparative analysis are in 2004 and 2010. Accelerators of socio-economic development - number of entrepreneur investors, investment in fixed assets and current assets ratio in multiple regression model are analytically filtered between twenty-six independent variables as variables of the dominant influence on GDP per capita in 2010 as dependent variable. Results of multivariate cluster analysis of twentyone Croatian Counties are interpreted also in the sense of three Croatian NUTS 2 regions according to European nomenclature of regional territorial division of Croatia. 5. Multivariate Analysis of Industrial Scale Fermentation Data Mears, Lisa; Nørregård, Rasmus; Stocks, Stuart M. 2015-01-01 Multivariate analysis allows process understanding to be gained from the vast and complex datasets recorded from fermentation processes, however the application of such techniques to this field can be limited by the data pre-processing requirements and data handling. In this work many iterations...... of multivariate modelling were carried out using different data pre-processing and scaling methods in order to extract the trends from the industrial data set, obtained from a production process operating in Novozymes A/S. This data set poses challenges for data analysis, combining both online and offline......, with an average prediction error of 7.6%. A methodology is proposed for applying multivariate analysis to industrial scale batch process data.... 6. Simplicial band depth for multivariate functional data López-Pintado, Sara 2014-03-05 We propose notions of simplicial band depth for multivariate functional data that extend the univariate functional band depth. The proposed simplicial band depths provide simple and natural criteria to measure the centrality of a trajectory within a sample of curves. Based on these depths, a sample of multivariate curves can be ordered from the center outward and order statistics can be defined. Properties of the proposed depths, such as invariance and consistency, can be established. A simulation study shows the robustness of this new definition of depth and the advantages of using a multivariate depth versus the marginal depths for detecting outliers. Real data examples from growth curves and signature data are used to illustrate the performance and usefulness of the proposed depths. © 2014 Springer-Verlag Berlin Heidelberg. 7. A MATLAB companion for multivariable calculus Cooper, Jeffery 2001-01-01 Offering a concise collection of MatLab programs and exercises to accompany a third semester course in multivariable calculus, A MatLab Companion for Multivariable Calculus introduces simple numerical procedures such as numerical differentiation, numerical integration and Newton''s method in several variables, thereby allowing students to tackle realistic problems. The many examples show students how to use MatLab effectively and easily in many contexts. Numerous exercises in mathematics and applications areas are presented, graded from routine to more demanding projects requiring some programming. Matlab M-files are provided on the Harcourt/Academic Press web site at http://www.harcourt-ap.com/matlab.html.* Computer-oriented material that complements the essential topics in multivariable calculus* Main ideas presented with examples of computations and graphics displays using MATLAB * Numerous examples of short code in the text, which can be modified for use with the exercises* MATLAB files are used to implem... 8. Acoustic comfort in eating establishments Svensson, David; Jeong, Cheol-Ho; Brunskog, Jonas 2014-01-01 The subjective concept of acoustic comfort in eating establishments has been investigated in this study. The goal was to develop a predictive model for the acoustic comfort, by means of simple objective parameters, while also examining which other subjective acoustic parameters could help explain...... the feeling of acoustic comfort. Through several layers of anal ysis, acoustic comfort was found to be rather complex, and could not be explained entirely by common subjective parameters such as annoyance, intelligibility or privacy. A predictive model for the mean acoustic comfort for an eating establishment... 9. LEARNING GRANGER CAUSALITY GRAPHS FOR MULTIVARIATE NONLINEAR TIME SERIES Wei GAO; Zheng TIAN 2009-01-01 An information theory method is proposed to test the. Granger causality and contemporaneous conditional independence in Granger causality graph models. In the graphs, the vertex set denotes the component series of the multivariate time series, and the directed edges denote causal dependence, while the undirected edges reflect the instantaneous dependence. The presence of the edges is measured by a statistics based on conditional mutual information and tested by a permutation procedure. Furthermore, for the existed relations, a statistics based on the difference between general conditional mutual information and linear conditional mutual information is proposed to test the nonlinearity. The significance of the nonlinear test statistics is determined by a bootstrap method based on surrogate data. We investigate the finite sample behavior of the procedure through simulation time series with different dependence structures, including linear and nonlinear relations. 10. Analysis of multivariate social science data Bartholomew, David J; Galbraith, Jane; Moustaki, Irini 2008-01-01 Drawing on the authors' varied experiences working and teaching in the field, Analysis of Multivariate Social Science Data, Second Editionenables a basic understanding of how to use key multivariate methods in the social sciences. With updates in every chapter, this edition expands its topics to include regression analysis, confirmatory factor analysis, structural equation models, and multilevel models. After emphasizing the summarization of data in the first several chapters, the authors focus on regression analysis. This chapter provides a link between the two halves of the book, signal 11. Starting up unstable multivariable controllers safety Stoustrup, J.; Niemann, Hans Henrik The problem of superimposing a multivariable controller on a running plant is considered. A simple but effective controller architecture is suggested which allows the transition from a conventional controller to a full multivariable controller to take place in a continuous way. This architecture...... allows for unstable controllers to be handled in a reliable way. Moreover, bandwidth properties can be tuned separately. It is shown how this architecture can be extended to provide a useful tool to implement gain scheduled controllers in the same fashion.... 12. Characterization of acoustic effects on flame structures by beam deflection technique Bedat, B.; Kostiuk, L.W.; Cheng, R.K. 1993-10-01 This work shows that the acoustic effects are the causes of the small amplitude flame wrinkling and movements seen in all the different gravitational conditions. The comparison between the acoustic velocity and beam deflection spectra for the two conditions studied (glass beads and fiber glass) demonstrates clearly this flame/acoustic coupling. This acoustic study shows that the burner behaves like a Helmholtz resonator. The estimated resonance frequency corresponds well to the experimental measurements. The fiber glass damps the level of the resonance frequency and the flame motion. The changes shown in normalized beam deflection spectra give further support of this damping. This work demonstrates that the acoustics has a direct influence on flame structure in the laminar case and the preliminary results in turbulent case also show a strong coupling. The nature of this flame/acoustic coupling are still not well understood. Further investigation should include determining the frequency limits and the sensitivity of the flame to acoustic perturbations. 13. Quadrotor system identification using the multivariate multiplex b-spline Visser, T.; De Visser, C.C.; Van Kampen, E.J. 2015-01-01 A novel method for aircraft system identification is presented that is based on a new multivariate spline type; the multivariate multiplex B-spline. The multivariate multiplex B-spline is a generalization of the recently introduced tensor-simplex B-spline. Multivariate multiplex splines obtain simil 14. The role of classroom acoustics on vocal intensity regulation and speakers’ comfort Pelegrin Garcia, David investigated the relationships between the classroom acoustic condition and teachers’ voice, focusing on their vocal intensity, and between the classroom acoustic condition and the sensation of acoustic comfort for a speaker. In the presence of low background noise levels, teachers were found to adjust...... in average teacher-to-student distance, but some of the variation was due to the room acoustic condition. The amount of vocal intensity variation with the room acoustic condition increased with the distance between teacher and student. In field measurements performed during typical working days, teachers......Teachers are one of the professional groups with the highest risk of suffering from voice disorders. Teachers point out classroom acoustics among the potential hazards affecting their vocal health, together with air dryness, background noise, and other environmental factors. The present project has... 15. A study of the acoustical radiation force considering attenuation Wu, RongRong; Liu, XiaoZhou; Gong, XiuFen 2013-07-01 Acoustical tweezer is a primary application of the radiation force of a sound field. When an ultrasound focused beam passes through a micro-particle, like a cell or living biological specimens, the particle will be manipulated accurately without physical contact and invasion, due to the three-dimensional acoustical trapping force. Based on the Ray acoustics approach in the Mie regime, this work discusses the effects on the particle caused by Gaussian focused ultrasound, studies the acoustical trapping force of spherical Mie particles by ultrasound in any position, and analyzes the numerical calculation on the two-dimensional acoustical radiation force. This article also analyzes the conditions for the acoustical trapping phenomenon, and discusses the impact of the initial position and size of the particle on the magnitude of the acoustical radiation force. Furthermore, this paper considers the ultrasonic attenuation in a particle in the case of two-dimension, studies the attenuation's effects on the acoustical trapping force, and amends the calculation to the ordinary case with attenuation. 16. An approach to the linear multivariable servomechanism problem. Young, P. C.; Willems, J. C. 1972-01-01 This paper presents a state-space approach to the multivariable 'type one' servomechanism problem. Necessary and sufficient conditions for the controllability of such systems are derived and applied to the observability of the (dual) state reconstructor problem for a system with an unknown constant input. The paper also presents a simple systematic design algorithm which provides type one servomechanism performance to command inputs, together with pre-specified closed-loop pole locations. Examples are given to illustrate the utility of the design procedure. 17. Smoothed Semiparametric Estimation on Multivariate Long Memory Processes Pumi, Guilherme 2012-01-01 In this paper we propose and study a general class of Gaussian Semiparametric Estimators (GSE) of the fractional differencing parameter in the context of long-range dependent multivariate time series. We establish large sample properties of the estimator without assuming Gaussianity. The class of models considered here satisfies simple conditions on the spectral density function, restricted to a small neighborhood of the zero frequency and includes important class of VARFIMA processes. We also present a simulation study to assess the finite sample properties of the proposed estimator based on a smoothed version of the GSE which supports its competitiveness. 18. A Century of Acoustic Metrology Rasmussen, Knud 1998-01-01 The development in acoustic measurement technique over the last century is reviewed with special emphasis on the metrological aspect.......The development in acoustic measurement technique over the last century is reviewed with special emphasis on the metrological aspect.... 19. Advanced Active Acoustics Lab (AAAL) Federal Laboratory Consortium — The Advanced Active Acoustics Lab (AAAL) is a state-of-the-art Undersea Warfare (USW) acoustic data analysis facility capable of both active and passive underwater... 20. Multiscale and Multivariate Visualizations of Software Evolution Voinea, Lucian; Telea, Alexandru 2006-01-01 Software evolution visualization is a promising technique for assessing the software development process. We study how complex correlations of software evolution attributes can be made using multivariate visualization techniques. We use a combination of color and textures to depict up to four artifa 1. Net analyte signal calculation for multivariate calibration Ferre, J.; Faber, N.M. 2003-01-01 A unifying framework for calibration and prediction in multivariate calibration is shown based on the concept of the net analyte signal (NAS). From this perspective, the calibration step can be regarded as the calculation of a net sensitivity vector, whose length is the amount of net signal when the 2. A KIND OF MULTIVARIATE NURBS SURFACES Ren-HongWang; Chong-JunLi 2004-01-01 The purpose of this paper is to construct a kind of multivariate NURBS surfaces by using the bivariate B-splines in the space S1/2(Δmn(2) and discuss some properties of this kind of NURBS surfaces with multiple knots on the type-2 triangulation. 3. Visualization of Multivariate Athlete Performance Data Telea, A.; Hillerin, P. de; Valeanu, V. 2007-01-01 We present a set of visualization methods for the analysis of multivariate data recorded from the measurement of the performance of athletes during training. We use a modified training device to measure the force, acceleration, displacement, and speed of the athlete’s feet and arms while performing 4. Using Matlab in a Multivariable Calculus Course. Schlatter, Mark D. The benefits of high-level mathematics packages such as Matlab include both a computer algebra system and the ability to provide students with concrete visual examples. This paper discusses how both capabilities of Matlab were used in a multivariate calculus class. Graphical user interfaces which display three-dimensional surfaces, contour plots,… 5. Multivariate data analysis of 2 DE data Wulff, Tune; Jokumsen, Alfred; Jessen, Flemming achieved by 2-DE. Protein spots, which individually or in combination with other spots varied according to hypoxia were found by multivariate data analysis (partial least squares regression) on group scaled data (normalised spot volumes) followed by selection of significant spots by jack-knifing. Tandem... 6. Ranking multivariate GARCH models by problem dimension M. Caporin (Massimiliano); M.J. McAleer (Michael) 2010-01-01 textabstractIn the last 15 years, several Multivariate GARCH (MGARCH) models have appeared in the literature. The two most widely known and used are the Scalar BEKK model of Engle and Kroner (1995) and Ding and Engle (2001), and the DCC model of Engle (2002). Some recent research has begun to examin 7. Multivariate model for test response analysis Krishnan, S.; Kerkhoff, H.G. 2010-01-01 A systematic approach to construct an effective multivariate test response model for capturing manufacturing defects in electronic products is described. The effectiveness of the model is demonstrated by its capability in reducing the number of test-points, while achieving the maximal coverage attai 8. Approaches to Assessment in Multivariate Analysis. O'Connell, Ann A. This paper reviews trends in assessment in quantitative courses and illustrates several options and approaches to assessment for advanced courses at the graduate level, especially in multivariate analysis. The paper provides a summary of how a researcher has used alternatives to traditional methods of assessment in a course on multivariate… 9. Acoustics of courtyard theatres WANG Jiqing 2008-01-01 The traditional Chinese theatre was often built with a courtyard. In such open-top space, the absence of a roof would mean little reverberation and non-diffused sound field.Acoustically the situation is quite different from that of any enclosed space. The refore, theclassic room acoustics, such as Sabine reverberation formula, would no longer be applicable due to the lack of sound reflections from the ceiling. As the parameter of reverberation time T30 shows the decay rate only, it would not properly characterize the prominent change in the fine structure of the echogram, particularly in case of a large reduction of reflections during the decay process. The sense of reverbrance in a courtyard space would differ noticeably from that of the equivalent 3D-T30 in an enclosed space. Based upon the characteristic analysis of the sound field in an open-top space, this paper presents a preliminary study on the acoustics of the courtyard theatres. 10. Acoustics waves and oscillations Sen, S.N. 2013-01-01 Parameters of acoustics presented in a logical and lucid style Physical principles discussed with mathematical formulations Importance of ultrasonic waves highlighted Dispersion of ultrasonic waves in viscous liquids explained This book presents the theory of waves and oscillations and various applications of acoustics in a logical and simple form. The physical principles have been explained with necessary mathematical formulation and supported by experimental layout wherever possible. Incorporating the classical view point all aspects of acoustic waves and oscillations have been discussed together with detailed elaboration of modern technological applications of sound. A separate chapter on ultrasonics emphasizes the importance of this branch of science in fundamental and applied research. In this edition a new chapter ''Hypersonic Velocity in Viscous Liquids as revealed from Brillouin Spectra'' has been added. The book is expected to present to its readers a comprehensive presentation of the subject matter... 11. Multivariate extended skew-t distributions and related families Arellano-Valle, Reinaldo B. 2010-12-01 A class of multivariate extended skew-t (EST) distributions is introduced and studied in detail, along with closely related families such as the subclass of extended skew-normal distributions. Besides mathematical tractability and modeling flexibility in terms of both skewness and heavier tails than the normal distribution, the most relevant properties of the EST distribution include closure under conditioning and ability to model lighter tails as well. The first part of the present paper examines probabilistic properties of the EST distribution, such as various stochastic representations, marginal and conditional distributions, linear transformations, moments and in particular Mardia’s measures of multivariate skewness and kurtosis. The second part of the paper studies statistical properties of the EST distribution, such as likelihood inference, behavior of the profile log-likelihood, the score vector and the Fisher information matrix. Especially, unlike the extended skew-normal distribution, the Fisher information matrix of the univariate EST distribution is shown to be non-singular when the skewness is set to zero. Finally, a numerical application of the conditional EST distribution is presented in the context of confidential data perturbation. 12. Acoustically Induced Vibration of Structures: Reverberant Vs. Direct Acoustic Testing Kolaini, Ali R.; O'Connell, Michael R.; Tsoi, Wan B. 2009-01-01 Large reverberant chambers have been used for several decades in the aerospace industry to test larger structures such as solar arrays and reflectors to qualify and to detect faults in the design and fabrication of spacecraft and satellites. In the past decade some companies have begun using direct near field acoustic testing, employing speakers, for qualifying larger structures. A limited test data set obtained from recent acoustic tests of the same hardware exposed to both direct and reverberant acoustic field testing has indicated some differences in the resulting structural responses. In reverberant acoustic testing, higher vibration responses were observed at lower frequencies when compared with the direct acoustic testing. In the case of direct near field acoustic testing higher vibration responses appeared to occur at higher frequencies as well. In reverberant chamber testing and direct acoustic testing, standing acoustic modes of the reverberant chamber or the speakers and spacecraft parallel surfaces can strongly couple with the fundamental structural modes of the test hardware. In this paper data from recent acoustic testing of flight hardware, that yielded evidence of acoustic standing wave coupling with structural responses, are discussed in some detail. Convincing evidence of the acoustic standing wave/structural coupling phenomenon will be discussed, citing observations from acoustic testing of a simple aluminum plate. The implications of such acoustic coupling to testing of sensitive flight hardware will be discussed. The results discussed in this paper reveal issues with over or under testing of flight hardware that could pose unanticipated structural and flight qualification issues. Therefore, it is of paramount importance to understand the structural modal coupling with standing acoustic waves that has been observed in both methods of acoustic testing. This study will assist the community to choose an appropriate testing method and test setup in 13. Room Acoustical Fields Mechel, Fridolin 2013-01-01 This book presents the theory of room acoustical fields and revises the Mirror Source Methods for practical computational use, emphasizing the wave character of acoustical fields. The presented higher methods include the concepts of “Mirror Point Sources” and “Corner sources which allow for an excellent approximation of complex room geometries and even equipped rooms. In contrast to classical description, this book extends the theory of sound fields describing them by their complex sound pressure and the particle velocity. This approach enables accurate descriptions of interference and absorption phenomena. 14. Acoustic black holes Visser, M 1999-01-01 Acoustic propagation in a moving fluid provides a conceptually clean and powerful analogy for understanding black hole physics. As a teaching tool, the analogy is useful for introducing students to both General Relativity and fluid mechanics. As a research tool, the analogy helps clarify what aspects of the physics are kinematics and what aspects are dynamics. In particular, Hawking radiation is a purely kinematical effect, whereas black hole entropy is intrinsically dynamical. Finally, I discuss the fact that with present technology acoustic Hawking radiation is almost experimentally testable. 15. Humanitarian mine detection by acoustic resonance Kercel, S.W. 1998-03-01 The JASON Committee at MITRE Corp. was tasked by DARPA to inquire into suitable technologies for humanitarian mine detection. Acoustic resonance was one of the very few technologies that the JASONs determined might be promising for the task, but was as yet unexplored at the time that they conducted their inquiry. The objective of this Seed Money investigation into acoustic resonance was to determine if it would be feasible to use acoustic resonance to provide an improvement to present methods for humanitarian mine detection. As detailed in this report, acoustic resonance methods do not appear to be feasible for this task. Although acoustic resonant responses are relatively easy to detect when they exist, they are very difficult to excite by the non-contact means that must be used for buried objects. Despite many different attempts, this research did not discover any practical means of using sound to excite resonant responses in objects known to have strong resonances. The shaker table experiments did see an effect that might be attributable to the resonance of the object under test, but the effect was weak, and exploited the a priori knowledge of the resonant frequency of the object under test to distinguish it from the background. If experiments that used objects known to have strong acoustic resonances produced such marginal results, this does not seem to be a practical method to detect objects with weak resonances or non-existent resonances. The results of this work contribute to the ORNL countermine initiative. ORNL is exploring several unconventional mine detection technologies, and is proposed to explore others. Since this research has discovered some major pitfalls in non-metallic mine detection, this experience will add realism to other strategies proposed for mine detection technologies. The experiment provided hands-on experience with inert plastic mines under field conditions, and gives ORNL additional insight into the problems of developing practical 16. Auditory event-related responses to diphthongs in different attention conditions Morris, David Jackson; Steinmetzger, Kurt; Tøndering, John 2016-01-01 The modulation of auditory event-related potentials (ERP) by attention generally results in larger amplitudes when stimuli are attended. We measured the P1-N1-P2 acoustic change complex elicited with synthetic overt (second formant, F2 = 1000 Hz) and subtle (F2 = 100 Hz) diphthongs, while subjects....... Multivariate analysis of ERP components from the rising F2 changes showed main effects of attention on P2 amplitude and latency, and N1-P2 amplitude. P2 amplitude decreased by 40% between the attend and ignore conditions, and by 60% between the attend and divert conditions. The effect of diphthong magnitude...... was significant for components from a broader temporal window which included P1 latency and N1 amplitude. N1 latency did not vary between attention conditions, a finding that may be related to stimulation with a continuous vowel. These data show that a discernible P1-N1-P2 response can be observed to subtle vowel... 17. Covariate selection in multivariate spatial analysis of ovine parasitic infection. Musella, V; Catelan, D; Rinaldi, L; Lagazio, C; Cringoli, G; Biggeri, A 2011-05-01 Gastrointestinal (GI) strongyle and fluke infections remain one of the main constraints on health and productivity in sheep dairy production. A cross-sectional survey was conducted in 2004-2005 on ovine farms in the Campania region of southern Italy in order to evaluate the prevalence of Haemonchus contortus, Fasciola hepatica, Dicrocoelium dendriticum and Calicophoron daubneyi from among other parasitic infections. In the present work, we focused on the role of the ecological characteristics of the pasture environment while accounting for the underlying long range geographical risk pattern. Bayesian multivariate spatial statistical analysis was used. A systematic grid (10 km×10 km) sampling approach was used. Laboratory procedures were based on the FLOTAC technique to detect and count eggs of helminths. A Geographical Information System (GIS) was constructed by using environmental data layers. Data on each of these layers were then extracted for pasturing areas that were previously digitalized aerial images of the ovine farms. Bayesian multivariate statistical analyses, including improper multivariate conditional autoregressive models, were used to select covariates on a multivariate spatially structured risk surface. Out of the 121 tested farms, 109 were positive for H. contortus, 81 for D. dendriticum, 17 for C. daubneyi and 15 for F. hepatica. The statistical analysis highlighted a north-south long range spatially structured pattern. This geographical pattern is treated here as a confounder, because the main interest was in the causal role of ecological covariates at the level of each pasturing area. A high percentage of pasture and impermeable soil were strong predictors of F. hepatica risk and a high percentage of wood was a strong predictor of C. daubneyi. A high percentage of wood, rocks and arable soil with sparse trees explained the spatial distribution of D. dendriticum. Sparse vegetation, river, mixed soil and permeable soil explained the spatial 18. From Architectural Acoustics to Acoustical Architecture Using Computer Simulation Schmidt, Anne Marie Due; Kirkegaard, Poul Henning 2005-01-01 Architectural acoustics design has in the past been based on simple design rules. However, with a growing complexity in architectural acoustics and the emergence of room acoustic simulation programmes with considerable potential, it is now possible to subjectively analyse and evaluate acoustic...... properties prior to the actual construction of a building. With the right tools applied, acoustic design can become an integral part of the architectural design process. The aim of this paper is to investigate the field of application that an acoustic simulation programme can have during an architectural...... acoustic design process and to set up a strategy to develop future programmes. The emphasis is put on the first three out of four phases in the working process of the architect and a case study is carried out in which each phase is represented by typical results ? as exemplified with reference... 19. Localization of acoustic sensors from passive Green's function estimation. Nowakowski, Thibault; Daudet, Laurent; de Rosny, Julien 2015-11-01 A number of methods have recently been developed for passive localization of acoustic sensors, based on the assumption that the acoustic field is diffuse. This article presents the more general case of equipartition fields, which takes into account reflections off boundaries and/or scatterers. After a thorough discussion on the fundamental differences between the diffuse and equipartition models, it is shown that the method is more robust when dealing with wideband noise sources. Finally, experimental results show, for two types of boundary conditions, that this approach is especially relevant when acoustic sensors are close to boundaries. 20. Development of Acoustic Sensors for the ANTARES Experiment Naumann, C L; Graf, K; Hoessl, J; Kappes, A; Karg, T; Katz, U; Lahmann, R; Salomon, K; Naumann, Christopher Lindsay; Anton, Gisela; Graf, Kay; Hoessl, Juergen; Kappes, Alexander; Karg, Timo; Katz, Uli; Lahmann, Robert; Salomon, Karsten 2005-01-01 In order to study the possibility of acoustic detection of ultra-high energy neutrinos in water, our group is planning to deploy and operate an array of acoustic sensors using the ANTARES Neutrino telescope in the Mediterranean Sea. Therefore, acoustic sensor hardware has to be developed which is both capable of operation under the hostile conditions of the deep sea and at the same time provides the high sensitivity necessary to detect the weak pressure signals resulting from the neutrino's interaction in water. In this paper, two different approaches to building such sensors, as well as performance studies in the laboratory and in situ, are presented. 1. Matrix-based, finite-difference algorithms for computational acoustics Davis, Sanford 1990-01-01 A compact numerical algorithm is introduced for simulating multidimensional acoustic waves. The algorithm is expressed in terms of a set of matrix coefficients on a three-point spatial grid that approximates the acoustic wave equation with a discretization error of O(h exp 5). The method is based on tracking a local phase variable and its implementation suggests a convenient coordinate splitting along with natural intermediate boundary conditions. Results are presented for oblique plane waves and compared with other procedures. Preliminary computations of acoustic diffraction are also considered. 2. Acoustic radiation force analysis using finite difference time domain method. Grinenko, A; Wilcox, P D; Courtney, C R P; Drinkwater, B W 2012-05-01 Acoustic radiation force exerted by standing waves on particles is analyzed using a finite difference time domain Lagrangian method. This method allows the acoustic radiation force to be obtained directly from the solution of nonlinear fluid equations, without any assumptions on size or geometry of the particles, boundary conditions, or acoustic field amplitude. The model converges to analytical results in the limit of small particle radii and low field amplitudes, where assumptions within the analytical models apply. Good agreement with analytical and numerical models based on solutions of linear scattering problems is observed for compressible particles, whereas some disagreement is detected when the compressibility of the particles decreases. 3. Acoustics forces on a solid sphere in focused sound fields and their use for acoustical traps Cutanda Henriquez, Vicente; Juhl, Peter Møller; Kristensen, Søren H. 2009-01-01 in the cases of hazardous substances, processing of materials under pure conditions, handling of fragile or sticky objects, for instance. Several theoretical investigations on the use of focused Gaussian and Bessel acoustic beams have been reported in literature. In those papers, water has been assumed... 4. Usual Dietary Intakes: SAS Macros for Fitting Multivariate Measurement Error Models & Estimating Multivariate Usual Intake Distributions The following SAS macros can be used to create a multivariate usual intake distribution for multiple dietary components that are consumed nearly every day or episodically. A SAS macro for performing balanced repeated replication (BRR) variance estimation is also included. 5. Evoked acoustic emission Elberling, C; Parbo, J; Johnsen, N J; 1985-01-01 Stimulated acoustic emissions were recorded in response to tonal stimuli at 60 dB p.e. SPL in a small group of normal-hearing adults. Power spectral analysis reveals that the evoked activity from each ear contains energy in preferential frequency bands and the change of stimulus frequency has onl... 6. Evoked acoustic emission Elberling, C; Parbo, J; Johnsen, N J; 1985-01-01 Stimulated acoustic emissions were recorded in response to tonal stimuli at 60 dB p.e. SPL in a small group of normal-hearing adults. Power spectral analysis reveals that the evoked activity from each ear contains energy in preferential frequency bands and the change of stimulus frequency has only... 7. Indigenous Acoustic Detection. 1982-01-26 considerable distances, and they act as good sensors of human presence. Though singing insects are ubiquitous in warm areas, even in the desert ( Nevo and...methodology. DTIC. CD-58-PL. Lloyd, J. E. 1981. Personnel communication. Nevo , E. and S. A. Blondheim. 1972. Acoustic isolation in the speciation of 8. Deep Water Ocean Acoustics 2015-04-15 sound speed profile is range-independent; since there is little expectation there will be significant mesoscale phenomenon given the lack of solar ...34 Journal of the Acoustical Society of America 93 (4), 1736-1742 (1993). 2 Chris H. Harrison and Martin Siderius, "Effective Parameters for Matched 9. Numerical analysis of acoustic impedance microscope utilizing acoustic lens transducer to examine cultured cells. Gunawan, Agus Indra; Hozumi, Naohiro; Takahashi, Kenta; Yoshida, Sachiko; Saijo, Yoshifumi; Kobayashi, Kazuto; Yamamoto, Seiji 2015-12-01 A new technique is proposed for non-contact quantitative cell observation using focused ultrasonic waves. This technique interprets acoustic reflection intensity into the characteristic acoustic impedance of the biological cell. The cells are cultured on a plastic film substrate. A focused acoustic beam is transmitted through the substrate to its interface with the cell. A two-dimensional (2-D) reflection intensity profile is obtained by scanning the focal point along the interface. A reference substance is observed under the same conditions. These two reflections are compared and interpreted into the characteristic acoustic impedance of the cell based on a calibration curve that was created prior to the observation. To create the calibration curve, a numerical analysis of the sound field is performed using Fourier Transforms and is verified using several saline solutions. Because the cells are suspended by two plastic films, no contamination is introduced during the observation. In a practical observation, a sapphire lens transducer with a center frequency of 300 MHz was employed using ZnO thin film. The objects studied were co-cultured rat-derived glial (astrocyte) cells and glioma cells. The result was the clear observation of the internal structure of the cells. The acoustic impedance of the cells was spreading between 1.62 and 1.72 MNs/m(3). Cytoskeleton was indicated by high acoustic impedance. The introduction of cytochalasin-B led to a significant reduction in the acoustic impedance of the glioma cells; its effect on the glial cells was less significant. It is believed that this non-contact observation method will be useful for continuous cell inspections. 10. Oil and stock market volatility: A multivariate stochastic volatility perspective Vo, Minh, E-mail: minh.vo@metrostate.edu 2011-09-15 This paper models the volatility of stock and oil futures markets using the multivariate stochastic volatility structure in an attempt to extract information intertwined in both markets for risk prediction. It offers four major findings. First, the stock and oil futures prices are inter-related. Their correlation follows a time-varying dynamic process and tends to increase when the markets are more volatile. Second, conditioned on the past information, the volatility in each market is very persistent, i.e., it varies in a predictable manner. Third, there is inter-market dependence in volatility. Innovations that hit either market can affect the volatility in the other market. In other words, conditioned on the persistence and the past volatility in their respective markets, the past volatility of the stock (oil futures) market also has predictive power over the future volatility of the oil futures (stock) market. Finally, the model produces more accurate Value-at-Risk estimates than other benchmarks commonly used in the financial industry. - Research Highlights: > This paper models the volatility of stock and oil futures markets using the multivariate stochastic volatility model. > The correlation between the two markets follows a time-varying dynamic process which tends to increase when the markets are more volatile. > The volatility in each market is very persistent. > Innovations that hit either market can affect the volatility in the other market. > The model produces more accurate Value-at-Risk estimates than other benchmarks commonly used in the financial industry. 11. Multivariate Approaches to Classification in Extragalactic Astronomy Didier eFraix-Burnet 2015-08-01 Full Text Available Clustering objects into synthetic groups is a natural activity of any science. Astrophysics is not an exception and is now facing a deluge of data. For galaxies, the one-century old Hubble classification and the Hubble tuning fork are still largely in use, together with numerous mono- or bivariate classifications most often made by eye. However, a classification must be driven by the data, and sophisticated multivariate statistical tools are used more and more often. In this paper we review these different approaches in order to situate them in the general context of unsupervised and supervised learning. We insist on the astrophysical outcomes of these studies to show that multivariate analyses provide an obvious path toward a renewal of our classification of galaxies and are invaluable tools to investigate the physics and evolution of galaxies. 12. Sensitivity Limitations for Multivariable Linear Filtering Steven R. Weller 2007-01-01 Full Text Available This paper examines fundamental limitations in performance which apply to linear filtering problems associated with multivariable systems having as many inputs as outputs. The results of this paper quantify unavoidable limitations in the sensitivity of state estimates to process and measurement disturbances, as represented by the maximum singular values of the relevant transfer matrices. These limitations result from interpolation constraints imposed by open right half-plane poles and zeros in the transfer matrices linking process noise and output noise with state estimates. Using the Poisson integral inequality, this paper shows how sensitivity limitations and tradeoffs in multivariable filtering problems are intimately related to the directionality properties of the open right half-plane poles and zeros in these transfer matrices. 13. Multivariate max-stable spatial processes Genton, Marc G. 2015-02-11 Max-stable processes allow the spatial dependence of extremes to be modelled and quantified, so they are widely adopted in applications. For a better understanding of extremes, it may be useful to study several variables simultaneously. To this end, we study the maxima of independent replicates of multivariate processes, both in the Gaussian and Student-t cases. We define a Poisson process construction and introduce multivariate versions of the Smith Gaussian extreme-value, the Schlather extremal-Gaussian and extremal-t, and the Brown–Resnick models. We develop inference for the models based on composite likelihoods. We present results of Monte Carlo simulations and an application to daily maximum wind speed and wind gust. 14. Power Estimation in Multivariate Analysis of Variance Jean François Allaire 2007-09-01 Full Text Available Power is often overlooked in designing multivariate studies for the simple reason that it is believed to be too complicated. In this paper, it is shown that power estimation in multivariate analysis of variance (MANOVA can be approximated using a F distribution for the three popular statistics (Hotelling-Lawley trace, Pillai-Bartlett trace, Wilks likelihood ratio. Consequently, the same procedure, as in any statistical test, can be used: computation of the critical F value, computation of the noncentral parameter (as a function of the effect size and finally estimation of power using a noncentral F distribution. Various numerical examples are provided which help to understand and to apply the method. Problems related to post hoc power estimation are discussed. 15. Multivariate analysis of endometrial tissue fluorescence spectra Vaitkuviene, Aurelija; Auksorius, E.; Fuchs, D.; Gavriushin, V. 2002-10-01 Background and Objective: The detailed multivariate analysis of endometrial tissue fluorescence spectra was done. Spectra underlying features and classification algorithm were analyzed. An effort has been made to determine the importance of neopterin component in endometrial premalignization. Study Design/Materials and Methods: Biomedical tissue fluorescence was measured by excitation with the Nd YAG laser third harmonic. Multivariate analysis techniques were used to analyze fluorescence spectra. Biomedical optics group at Vilnius University analyzed the neopterin substance supplied by the Institute of Medical Chemistry and Biochemistry of Innsbruck University. Results: Seven statistically significant spectral compounds were found. The classification algorithm classifying samples to histopathological categories was developed and resulted in sensitivity of 80% and specificity 93% for malignant vs. hyperplastic and normal. Conclusions: Fluorescence spectra could be classified with high accuracy. Spectral variation underlying features can be extracted. Neopterin component might play an important role in endometrial hyperplasia development. 16. Multivariate Approaches to Classification in Extragalactic Astronomy Fraix-Burnet, Didier; Chattopadhyay, Asis Kumar 2015-01-01 Clustering objects into synthetic groups is a natural activity of any science. Astrophysics is not an exception and is now facing a deluge of data. For galaxies, the one-century old Hubble classification and the Hubble tuning fork are still largely in use, together with numerous mono-or bivariate classifications most often made by eye. However, a classification must be driven by the data, and sophisticated multivariate statistical tools are used more and more often. In this paper we review these different approaches in order to situate them in the general context of unsupervised and supervised learning. We insist on the astrophysical outcomes of these studies to show that multivariate analyses provide an obvious path toward a renewal of our classification of galaxies and are invaluable tools to investigate the physics and evolution of galaxies. 17. Multivariate Approaches to Classification in Extragalactic Astronomy Fraix-Burnet, Didier; Thuillard, Marc; Chattopadhyay, Asis Kumar 2015-08-01 Clustering objects into synthetic groups is a natural activity of any science. Astrophysics is not an exception and is now facing a deluge of data. For galaxies, the one-century old Hubble classification and the Hubble tuning fork are still largely in use, together with numerous mono- or bivariate classifications most often made by eye. However, a classification must be driven by the data, and sophisticated multivariate statistical tools are used more and more often. In this paper we review these different approaches in order to situate them in the general context of unsupervised and supervised learning. We insist on the astrophysical outcomes of these studies to show that multivariate analyses provide an obvious path toward a renewal of our classification of galaxies and are invaluable tools to investigate the physics and evolution of galaxies. 18. Holograms for acoustics Melde, Kai; Mark, Andrew G.; Qiu, Tian; Fischer, Peer 2016-09-01 Holographic techniques are fundamental to applications such as volumetric displays, high-density data storage and optical tweezers that require spatial control of intricate optical or acoustic fields within a three-dimensional volume. The basis of holography is spatial storage of the phase and/or amplitude profile of the desired wavefront in a manner that allows that wavefront to be reconstructed by interference when the hologram is illuminated with a suitable coherent source. Modern computer-generated holography skips the process of recording a hologram from a physical scene, and instead calculates the required phase profile before rendering it for reconstruction. In ultrasound applications, the phase profile is typically generated by discrete and independently driven ultrasound sources; however, these can only be used in small numbers, which limits the complexity or degrees of freedom that can be attained in the wavefront. Here we introduce monolithic acoustic holograms, which can reconstruct diffraction-limited acoustic pressure fields and thus arbitrary ultrasound beams. We use rapid fabrication to craft the holograms and achieve reconstruction degrees of freedom two orders of magnitude higher than commercial phased array sources. The technique is inexpensive, appropriate for both transmission and reflection elements, and scales well to higher information content, larger aperture size and higher power. The complex three-dimensional pressure and phase distributions produced by these acoustic holograms allow us to demonstrate new approaches to controlled ultrasonic manipulation of solids in water, and of liquids and solids in air. We expect that acoustic holograms will enable new capabilities in beam-steering and the contactless transfer of power, improve medical imaging, and drive new applications of ultrasound. 19. Acoustic field modulation in regenerators Hu, J. Y.; Wang, W.; Luo, E. C.; Chen, Y. Y. 2016-12-01 The regenerator is a key component that transfers energy between heat and work. The conversion efficiency is significantly influenced by the acoustic field in the regenerator. Much effort has been spent to quantitatively determine this influence, but few comprehensive experimental verifications have been performed because of difficulties in modulating and measuring the acoustic field. In this paper, a method requiring two compressors is introduced and theoretically investigated that achieves acoustic field modulation in the regenerator. One compressor outputs the acoustic power for the regenerator; the other acts as a phase shifter. A RC load dissipates the acoustic power out of both the regenerator and the latter compressor. The acoustic field can be modulated by adjusting the current in the two compressors and opening the RC load. The acoustic field is measured with pressure sensors instead of flow-field imaging equipment, thereby greatly simplifying the experiment. 20. Controlling sound with acoustic metamaterials Cummer, Steven A. ; Christensen, Johan; Alù, Andrea 2016-01-01 Acoustic metamaterials can manipulate and control sound waves in ways that are not possible in conventional materials. Metamaterials with zero, or even negative, refractive index for sound offer new possibilities for acoustic imaging and for the control of sound at subwavelength scales....... The combination of transformation acoustics theory and highly anisotropic acoustic metamaterials enables precise control over the deformation of sound fields, which can be used, for example, to hide or cloak objects from incident acoustic energy. Active acoustic metamaterials use external control to create......-scale metamaterial structures and converting laboratory experiments into useful devices. In this Review, we outline the designs and properties of materials with unusual acoustic parameters (for example, negative refractive index), discuss examples of extreme manipulation of sound and, finally, provide an overview... 1. Measurement of stiffness of standing trees and felled logs using acoustics: A review. Legg, Mathew; Bradley, Stuart 2016-02-01 This paper provides a review on the use of acoustics to measure stiffness of standing trees, stems, and logs. An outline is given of the properties of wood and how these are related to stiffness and acoustic velocity throughout the tree. Factors are described that influence the speed of sound in wood, including the different types of acoustic waves which propagate in tree stems and lumber. Acoustic tools and techniques that have been used to measure the stiffness of wood are reviewed. The reasons for a systematic difference between direct and acoustic measurements of stiffness for standing trees, and methods for correction, are discussed. Other techniques, which have been used in addition to acoustics to try to improve stiffness measurements, are also briefly described. Also reviewed are studies which have used acoustic tools to investigate factors that influence the stiffness of trees. These factors include different silvicultural practices, geographic and environmental conditions, and genetics. 2. Acoustic Bloch Wave Propagation in a Periodic Waveguide 1991-07-24 Distribution of Spherical Cavities," J. Acoust. Soc. Am. 81, 595-598. Arfken , G. (1985). Mathematical Methods for Physicists (Academic Press, Inc., New... mathematical -ystem of governing equations and boundary conditions describing lossy, linear acoustic waves in a periodic wave- guide is, under the...Translational Invariance The aim of this section is to present the mathematical system to be solved and show that it exhibits invariance under a certain 3. Acoustic radiation force and torque on an absorbing particle Silva, Glauber T 2013-01-01 Exact formulas of the radiation force and torque exerted on an absorbing particle in the Rayleigh scattering limit caused by an arbitrary harmonic acoustic wave are presented. They are used to analyze the trapping conditions by a single-beam acoustical tweezer based on a spherically focused ultrasound beam. Results reveal that particle's absorption has a pivotal role in single-beam trapping. Furthermore, we obtain the radiation torque induced by a Bessel beam in an on-axis particle. 4. Robust Evaluation of Multivariate Density Forecasts Dovern, Jonas; Manner, Hans 2016-01-01 We derive new tests for proper calibration of multivariate density forecasts based on Rosenblatt probability integral transforms. These tests have the advantage that they i) do not depend on the ordering of variables in the forecasting model, ii) are applicable to densities of arbitrary dimensions, and iii) have superior power relative to existing approaches. We furthermore develop adjusted tests that allow for estimated parameters and, consequently, can be used as in-sample specification tes... 5. Random matrix theory and multivariate statistics Diaz-Garcia, Jose A.; Jáimez, Ramon Gutiérrez 2009-01-01 Some tools and ideas are interchanged between random matrix theory and multivariate statistics. In the context of the random matrix theory, classes of spherical and generalised Wishart random matrix ensemble, containing as particular cases the classical random matrix ensembles, are proposed. Some properties of these classes of ensemble are analysed. In addition, the random matrix ensemble approach is extended and a unified theory proposed for the study of distributions for real normed divisio... 6. The evolution of multivariate maternal effects. Kuijper, Bram; Johnstone, Rufus A; Townley, Stuart 2014-04-01 There is a growing interest in predicting the social and ecological contexts that favor the evolution of maternal effects. Most predictions focus, however, on maternal effects that affect only a single character, whereas the evolution of maternal effects is poorly understood in the presence of suites of interacting traits. To overcome this, we simulate the evolution of multivariate maternal effects (captured by the matrix M) in a fluctuating environment. We find that the rate of environmental fluctuations has a substantial effect on the properties of M: in slowly changing environments, offspring are selected to have a multivariate phenotype roughly similar to the maternal phenotype, so that M is characterized by positive dominant eigenvalues; by contrast, rapidly changing environments favor Ms with dominant eigenvalues that are negative, as offspring favor a phenotype which substantially differs from the maternal phenotype. Moreover, when fluctuating selection on one maternal character is temporally delayed relative to selection on other traits, we find a striking pattern of cross-trait maternal effects in which maternal characters influence not only the same character in offspring, but also other offspring characters. Additionally, when selection on one character contains more stochastic noise relative to selection on other traits, large cross-trait maternal effects evolve from those maternal traits that experience the smallest amounts of noise. The presence of these cross-trait maternal effects shows that individual maternal effects cannot be studied in isolation, and that their study in a multivariate context may provide important insights about the nature of past selection. Our results call for more studies that measure multivariate maternal effects in wild populations. 7. The evolution of multivariate maternal effects. Bram Kuijper 2014-04-01 Full Text Available There is a growing interest in predicting the social and ecological contexts that favor the evolution of maternal effects. Most predictions focus, however, on maternal effects that affect only a single character, whereas the evolution of maternal effects is poorly understood in the presence of suites of interacting traits. To overcome this, we simulate the evolution of multivariate maternal effects (captured by the matrix M in a fluctuating environment. We find that the rate of environmental fluctuations has a substantial effect on the properties of M: in slowly changing environments, offspring are selected to have a multivariate phenotype roughly similar to the maternal phenotype, so that M is characterized by positive dominant eigenvalues; by contrast, rapidly changing environments favor Ms with dominant eigenvalues that are negative, as offspring favor a phenotype which substantially differs from the maternal phenotype. Moreover, when fluctuating selection on one maternal character is temporally delayed relative to selection on other traits, we find a striking pattern of cross-trait maternal effects in which maternal characters influence not only the same character in offspring, but also other offspring characters. Additionally, when selection on one character contains more stochastic noise relative to selection on other traits, large cross-trait maternal effects evolve from those maternal traits that experience the smallest amounts of noise. The presence of these cross-trait maternal effects shows that individual maternal effects cannot be studied in isolation, and that their study in a multivariate context may provide important insights about the nature of past selection. Our results call for more studies that measure multivariate maternal effects in wild populations. 8. Control of wastewater using multivariate control chart Nugraha, Jaka; Fatimah, Is; Prabowo, Rino Galang 2017-03-01 Wastewater treatment is a crucial process in industry cause untreated or improper treatment of wastewater may leads some problems affecting to the other parts of environmental aspects. For many kinds of wastewater treatments, the parameters of Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and the Total Suspend Solid (TSS) are usual parameters to be controlled as a standard. In this paper, the application of multivariate Hotteling T2 Individual was reported to control wastewater treatment. By using wastewater treatment data from PT. ICBP, east Java branch, while the fulfillment of quality standards are based on East Java Governor Regulation No. 72 Year 2013 on Standards of Quality of Waste Water Industry and / or Other Business Activities. The obtained results are COD and TSS has a correlation with BOD values with the correlation coefficient higher than 50%, and it is is also found that influence of the COD and TSS to BOD values are 82% and 1.9% respectively. Based on Multivariate control chart Individual T2 Hotteling, it is found that BOD-COD and BOD-TSS are each one subgroup that are outside the control limits. Thus, it can be said there is a process that is not multivariate controlled, but univariately the variables of BOD, COD and TSS are within specification (standard quality) that has been determined. 9. Bayesian Inference of a Multivariate Regression Model Marick S. Sinay 2014-01-01 Full Text Available We explore Bayesian inference of a multivariate linear regression model with use of a flexible prior for the covariance structure. The commonly adopted Bayesian setup involves the conjugate prior, multivariate normal distribution for the regression coefficients and inverse Wishart specification for the covariance matrix. Here we depart from this approach and propose a novel Bayesian estimator for the covariance. A multivariate normal prior for the unique elements of the matrix logarithm of the covariance matrix is considered. Such structure allows for a richer class of prior distributions for the covariance, with respect to strength of beliefs in prior location hyperparameters, as well as the added ability, to model potential correlation amongst the covariance structure. The posterior moments of all relevant parameters of interest are calculated based upon numerical results via a Markov chain Monte Carlo procedure. The Metropolis-Hastings-within-Gibbs algorithm is invoked to account for the construction of a proposal density that closely matches the shape of the target posterior distribution. As an application of the proposed technique, we investigate a multiple regression based upon the 1980 High School and Beyond Survey. 10. Compressive tracking with incremental multivariate Gaussian distribution Li, Dongdong; Wen, Gongjian; Zhu, Gao; Zeng, Qiaoling 2016-09-01 Various approaches have been proposed for robust visual tracking, among which compressive tracking (CT) yields promising performance. In CT, Haar-like features are efficiently extracted with a very sparse measurement matrix and modeled as an online updated naïve Bayes classifier to account for target appearance change. The naïve Bayes classifier ignores overlap between Haar-like features and assumes that Haar-like features are independently distributed, which leads to drift in complex scenario. To address this problem, we present an extended CT algorithm, which assumes that all Haar-like features are correlated with each other and have multivariate Gaussian distribution. The mean vector and covariance matrix of multivariate normal distribution are incrementally updated with constant computational complexity to adapt to target appearance change. Each frame is associated with a temporal weight to expend less modeling power on old observation. Based on temporal weight, an update scheme with changing but convergent learning rate is derived with strict mathematic proof. Compared with CT, our extended algorithm achieves a richer representation of target appearance. The incremental multivariate Gaussian distribution is integrated into the particle filter framework to achieve better tracking performance. Extensive experiments on the CVPR2013 tracking benchmark demonstrate that our proposed tracker achieves superior performance both qualitatively and quantitatively over several state-of-the-art trackers. 11. Observation of a single-beam gradient force acoustical trap for elastic particles: acoustical tweezers Baresch, Diego; Marchiano, Régis 2016-01-01 The ability to manipulate matter precisely is critical for the study and development of a large variety of systems. Optical tweezers are excellent tools to handle particles ranging in size from a few micrometers to hundreds of nanometers but become inefficient and damaging on larger objects. We demonstrate for the first reported time the trapping of elastic particles by the large gradient force of a single acoustical beam in three dimensions. We show that at equal power, acoustical forces overtake by 8 orders of magnitude that of optical ones on macroscopic objects. Acoustical tweezers can push, pull and accurately control both the position of the particle and the forces exerted under damage-free conditions. The large spectrum of frequencies covered by coherent ultrasonic sources will provide a wide variety of manipulation possibilities from macro- to microscopic length scales. We believe our observations improve the prospects for wider use of non-contact manipulation in biology, biophysics, microfluidics and... 12. Acoustic simulations of Mudejar-Gothic churches. Galindo, Miguel; Zamarreño, Teófilo; Girón, Sara 2009-09-01 In this paper, an iterative process is used in order to estimate the values of absorption coefficients of those materials of which little is known in the literature, so that an acoustic simulation can be carried out in Mudejar-Gothic churches. The estimation of the scattering coefficients, which is even less developed, is based on the size of the irregularities. This methodology implemented is applied to six Mudejar-Gothic churches of Seville (southern Spain). The simulated monophonic acoustic parameters, both in the frequency domain and as a function of source-receiver distance (spatial distribution), are analyzed and compared with the in situ measures. Good agreement has been found between these sets of values, whereby each parameter is discussed in terms of the just noticeable difference. This procedure for existing buildings, especially for those which are rich in heritage, enables a reliable evaluation of the effect on the maintenance, restoration, and conditioning for new uses, as well as the recreation of the acoustic environment of ancient times. Along these lines, the acoustic influence of the timber roof and the presence of the public in these churches have also been studied. 13. Acoustic tomography in the atmospheric surface layer A. Ziemann Full Text Available Acoustic tomography is presented as a technique for remote monitoring of meteorological quantities. This method and a special algorithm of analysis can directly produce area-averaged values of meteorological parameters. As a result consistent data will be obtained for validation of numerical atmospheric micro-scale models. Such a measuring system can complement conventional point measurements over different surfaces. The procedure of acoustic tomography uses the horizontal propagation of sound waves in the atmospheric surface layer. Therefore, to provide a general overview of sound propagation under various atmospheric conditions a two-dimensional ray-tracing model according to a modified version of Snell's law is used. The state of the crossed atmosphere can be estimated from measurements of acoustic travel time between sources and receivers at different points. Derivation of area-averaged values of the sound speed and furthermore of air temperature results from the inversion of travel time values for all acoustic paths. Thereby, the applied straight ray two-dimensional tomographic model using SIRT (simultaneous iterative reconstruction technique is characterised as a method with small computational requirements, satisfactory convergence and stability properties as well as simple handling, especially, during online evaluation. Key words. Meteorology and atmospheric dynamics (turbulence; instruments and techniques. 14. Acoustic data transmission through a drillstring Drumheller, Douglas S. (Cedar Crest, NM) 1992-01-01 A method and apparatus for acoustically transmitting data along a drillstring is presented. In accordance with one embodiment of the present invention, acoustic data signals are conditioned to counteract distortions caused by the drillstring. Preferably, this conditioning step comprises multiplying each frequency component of the data signal by exp (-ikL) where L is the transmission length of the drillstring, k is the wave number in the drillstring at the frequency of each component and i is (-1).sup.1/2. In another embodiment of this invention, data signals having a frequency content in at least one passband of the drillstring are generated preferably traveling in only one direction (e.g., up the drillstring) while echoes in the drillstring resulting from the data transmission are suppressed. 15. Acoustic data transmission through a drillstring Drumheller, D.S. 1992-07-07 A method and apparatus for acoustically transmitting data along a drillstring are presented. In accordance with one embodiment of the present invention, acoustic data signals are conditioned to counteract distortions caused by the drillstring. Preferably, this conditioning step comprises multiplying each frequency component of the data signal by exp ([minus]ikL) where L is the transmission length of the drillstring, k is the wave number in the drillstring at the frequency of each component and i is ([minus]1)[sup 1/2]. In another embodiment of this invention, data signals having a frequency content in at least one passband of the drillstring are generated preferably traveling in only one direction (e.g., up the drillstring) while echoes in the drillstring resulting from the data transmission are suppressed. 20 figs. 16. Brain Metabolic Changes in Rats following Acoustic Trauma He, Jun; Zhu, Yejin; Aa, Jiye; Smith, Paul F.; De Ridder, Dirk; Wang, Guangji; Zheng, Yiwen 2017-01-01 Acoustic trauma is the most common cause of hearing loss and tinnitus in humans. However, the impact of acoustic trauma on system biology is not fully understood. It has been increasingly recognized that tinnitus caused by acoustic trauma is unlikely to be generated by a single pathological source, but rather a complex network of changes involving not only the auditory system but also systems related to memory, emotion and stress. One obvious and significant gap in tinnitus research is a lack of biomarkers that reflect the consequences of this interactive “tinnitus-causing” network. In this study, we made the first attempt to analyse brain metabolic changes in rats following acoustic trauma using metabolomics, as a pilot study prior to directly linking metabolic changes to tinnitus. Metabolites in 12 different brain regions collected from either sham or acoustic trauma animals were profiled using a gas chromatography mass spectrometry (GC/MS)-based metabolomics platform. After deconvolution of mass spectra and identification of the molecules, the metabolomic data were processed using multivariate statistical analysis. Principal component analysis showed that metabolic patterns varied among different brain regions; however, brain regions with similar functions had a similar metabolite composition. Acoustic trauma did not change the metabolite clusters in these regions. When analyzed within each brain region using the orthogonal projection to latent structures discriminant analysis sub-model, 17 molecules showed distinct separation between control and acoustic trauma groups in the auditory cortex, inferior colliculus, superior colliculus, vestibular nucleus complex (VNC), and cerebellum. Further metabolic pathway impact analysis and the enrichment overview with network analysis suggested the primary involvement of amino acid metabolism, including the alanine, aspartate and glutamate metabolic pathways, the arginine and proline metabolic pathways and the purine 17. Impact of acoustic cavitation on food emulsions. Krasulya, Olga; Bogush, Vladimir; Trishina, Victoria; Potoroko, Irina; Khmelev, Sergey; Sivashanmugam, Palani; Anandan, Sambandam 2016-05-01 The work explores the experimental and theoretical aspects of emulsification capability of ultrasound to deliver stable emulsions of sunflower oil in water and meat sausages. In order to determine optimal parameters for direct ultrasonic emulsification of food emulsions, a model was developed based on the stability of emulsion droplets in acoustic cavitation field. The study is further extended to investigate the ultrasound induced changes to the inherent properties of raw materials under the experimental conditions of sono-emulsification. 18. Flat acoustic lens by acoustic grating with curled slits Peng, Pai 2014-10-01 We design a flat sub-wavelength lens that can focus acoustic wave. We analytically study the transmission through an acoustic grating with curled slits, which can serve as a material with tunable impedance and refractive index for acoustic waves. The effective parameters rely on the geometry of the slits and are independent of frequency. A flat acoustic focusing lens by such acoustic grating with gradient effective refractive index is designed. The focusing effect is clearly observed in simulations and well predicted by the theory. We demonstrate that despite the large impedance mismatch between the acoustic lens and the matrix, the intensity at the focal point is still high due to Fabry-Perot resonance. 19. Manipulate acoustic waves by impedance matched acoustic metasurfaces Wu, Ying; Mei, Jun; Aljahdali, Rasha We design a type of acoustic metasurface, which is composed of carefully designed slits in a rigid thin plate. The effective refractive indices of different slits are different but the impedances are kept the same as that of the host medium. Numerical simulations show that such a metasurface can redirect or reflect a normally incident wave at different frequencies, even though it is impedance matched to the host medium. We show that the underlying mechanisms can be understood by using the generalized Snell's law, and a unified analytic model based on mode-coupling theory. We demonstrate some simple realization of such acoustic metasurface with real materials. The principle is also extended to the design of planar acoustic lens which can focus acoustic waves. Manipulate acoustic waves by impedance matched acoustic metasurfaces. 20. 离心泵空化状态下声发射信号的小波能量特征%Wavelet energy features of acoustic emission signals under centrifugal pump cavitation conditions 刘忠; 邹淑云; 李志鹏; 巨伟 2015-01-01 为了探究离心泵空化状态下声发射信号的频率分布特征及其变化规律，该文采用小波分析方法对离心泵空化试验过程中不同空化状态下的声发射信号进行了能量特征提取，研究了不同频段内声发射信号的能量特征随离心泵汽蚀余量变化的关系。试验分析结果表明，在离心泵的空化现象尚未出现以及不同的发展阶段，离心泵进、出口处声发射信号的全频段和各分频段绝对能量和相对能量的变化具有各不相同的特点。>31.25～62.5、>62.5～125和>125～250 kHz这3个分频段的绝对能量随空化状态改变而变化明显，且变化趋势与全频段的变化趋势类似。>31.25～62.5 kHz分频段的相对能量在空化状态变化过程中基本保持不变，而>62.5～125和>125～250 kHz 分频段的相对能量变化更为明显。研究结果可为离心泵空化状态的判别提供技术参考。%With the development of Acoustic Emission (AE) techniques, researches on the AE signals emitted during the cavitation process to judge whether the cavitation has occurred or not and its development degrees are getting more and more attentions. However, the frequency distribution features and their variation laws with the cavitation states of centrifugal pumps remain to be further studied. In this paper, the wavelet energy features of the AE signals under the cavitation conditions of a centrifugal pump were extracted with the wavelet analysis method, and the variation laws of these features were also revealed. Firstly, the cavitation processes of the centrifugal pump with constant flows and constant speeds at the 60%, 100%and 120%rated flow respectively were simulated on an open centrifugal pump test bench. Each cavitation process included such different stages as no cavitation, cavitation just appearing and cavitation developed with different degrees. Simultaneously, the corresponding operational parameters of the centrifugal pump 1. Derivatives of Multivariate Bernstein Operators and Smoothness with Jacobi Weights Jianjun Wang 2012-01-01 Full Text Available Using the modulus of smoothness, directional derivatives of multivariate Bernstein operators with weights are characterized. The obtained results partly generalize the corresponding ones for multivariate Bernstein operators without weights. 2. HIGHER ORDER MULTIVARIABLE NORLUND EULER-BERNOULLI POLYNOMIALS 刘国栋 2002-01-01 The definitions of higher order multivariable Norlund Euler polynomials and Norlund Bernoulli polynomials are presented and some of their important properties are expounded. Some identities involving recurrence sequences and higher order multivariable Norlund Euler-Bernoulli polynomials are established. 3. Acoustic absorption by sunspots Braun, D. C.; Labonte, B. J.; Duvall, T. L., Jr. 1987-01-01 The paper presents the initial results of a series of observations designed to probe the nature of sunspots by detecting their influence on high-degree p-mode oscillations in the surrounding photosphere. The analysis decomposes the observed oscillations into radially propagating waves described by Hankel functions in a cylindrical coordinate system centered on the sunspot. From measurements of the differences in power between waves traveling outward and inward, it is demonstrated that sunspots appear to absorb as much as 50 percent of the incoming acoustic waves. It is found that for all three sunspots observed, the amount of absorption increases linearly with horizontal wavenumber. The effect is present in p-mode oscillations with wavelengths both significantly larger and smaller than the diameter of the sunspot umbrae. Actual absorption of acoustic energy of the magnitude observed may produce measurable decreases in the power and lifetimes of high-degree p-mode oscillations during periods of high solar activity. 4. ACOUSTIC EMISSION ANALYZER J. J. Almeida-Pérez 2004-12-01 Full Text Available In this paper appears a solution for acoustic emission analysis commonly known as noise. For the accomplishmentof this work a personal computer is used, besides sensors (microphones and boards designed and built for signalconditioning. These components are part of a virtual instrument used for monitoring the acoustical emission. Themain goal of this work is to develop a virtual instrument that supplies many important data as the result of ananalysis allowing to have information in an easy and friendly way. Moreover this information is very useful forstudying and resolving several situations in planning, production and testing areas.The main characteristics of the virtual instrument are: signal analysis in time, effective power measurement inDecibels (dB, average intensity taken from the principle of paired microphones, as well as the data analysis infrequency. These characteristics are included to handle two information channels. 5. Electromagnetic acoustic imaging. Emerson, Jane F; Chang, David B; McNaughton, Stuart; Jeong, Jong Seob; Shung, K K; Cerwin, Stephen A 2013-02-01 Electromagnetic acoustic imaging (EMAI) is a new imaging technique that uses long-wavelength RF electromagnetic (EM) waves to induce ultrasound emission. Signal intensity and image contrast have been found to depend on spatially varying electrical conductivity of the medium in addition to conventional acoustic properties. The resultant conductivity- weighted ultrasound data may enhance the diagnostic performance of medical ultrasound in cancer and cardiovascular applications because of the known changes in conductivity of malignancy and blood-filled spaces. EMAI has a potential advantage over other related imaging techniques because it combines the high resolution associated with ultrasound detection with the generation of the ultrasound signals directly related to physiologically important electrical properties of the tissues. Here, we report the theoretical development of EMAI, implementation of a dual-mode EMAI/ultrasound apparatus, and successful demonstrations of EMAI in various phantoms designed to establish feasibility of the approach for eventual medical applications. 6. Theoretical and Experimental Study on the Acoustic Wave Energy After the Nonlinear Interaction of Acoustic Waves in Aqueous Media 兰朝凤; 李凤臣; 陈欢; 卢迪; 杨德森; 张梦 2015-01-01 Based on the Burgers equation and Manley-Rowe equation, the derivation about nonlinear interaction of the acoustic waves has been done in this paper. After nonlinear interaction among the low-frequency weak waves and the pump wave, the analytical solutions of acoustic waves’ amplitude in the field are deduced. The relationship between normalized energy of high-frequency and the change of acoustic energy before and after the nonlinear interaction of the acoustic waves is analyzed. The experimental results about the changes of the acoustic energy are presented. The study shows that new frequencies are generated and the energies of the low-frequency are modulated in a long term by the pump waves, which leads the energies of the low-frequency acoustic waves to change in the pulse trend in the process of the nonlinear interaction of the acoustic waves. The increase and decrease of the energies of the low-frequency are observed under certain typical conditions, which lays a foundation for practical engineering applications. 7. A multivariate process capability index with a spatial coefficient Wang Shaoxi; Wang Mingxin; Fan Xiaoya; Zhang Shengbing; Han Ru 2013-01-01 After analyzing the multivariate Cpm method (Chan et al.1991),this paper presents a spatial multivariate process capability index (PCI) method,which can solve a multivariate off-centered case and may provide references for assuring and improving process quality level while achieving an overall evaluation of process quality.Examples for calculating multivariate PCI are given and the experimental results show that the systematic method presented is effective and actual. 8. Acoustic emission source modeling Hora P. 2010-07-01 Full Text Available The paper deals with the acoustic emission (AE source modeling by means of FEM system COMSOL Multiphysics. The following types of sources are used: the spatially concentrated force and the double forces (dipole. The pulse excitation is studied in both cases. As a material is used steel. The computed displacements are compared with the exact analytical solution of point sources under consideration. 9. Acoustic Characterization of Soil 2007-11-02 ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER Dept. of Electrical & Computer Enginnering Dept Natural Resources...same transduction device is used for transmit and receive, and the broad-band mechanical matching between the transduction device and the acoustic...has a direct influence over the imaging depth for a given dynamic range. Figure 10 demonstrated the influence of the roundtrip propagation loss as a 10. Acoustic Communications for UUVs 2016-06-07 through use of high-gain, error-control coding coupled with a modified decision feedback equalizer (DFE) which allows the gain to be exploited prior to...finished it wait for feedback from the receiver. At the host each packet is decoded and displayed if it is correct, or added to a list of bad packets if it...Systems Laboratory, Florida Alantic University, July 1998. L. Freitag el al: ‘A Bidriectional Coherent Acoustic Communications Systems for Underwater 11. Acoustically enhanced heat transport Ang, Kar M.; Hung, Yew Mun; Tan, Ming K., E-mail: tan.ming.kwang@monash.edu [School of Engineering, Monash University Malaysia, 47500 Bandar Sunway, Selangor (Malaysia); Yeo, Leslie Y. [Micro/Nanophysics Research Laboratory, RMIT University, Melbourne, VIC 3001 (Australia); Friend, James R. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, California 92093 (United States) 2016-01-15 We investigate the enhancement of heat transfer in the nucleate boiling regime by inducing high frequency acoustic waves (f ∼ 10{sup 6} Hz) on the heated surface. In the experiments, liquid droplets (deionized water) are dispensed directly onto a heated, vibrating substrate. At lower vibration amplitudes (ξ{sub s} ∼ 10{sup −9} m), the improved heat transfer is mainly due to the detachment of vapor bubbles from the heated surface and the induced thermal mixing. Upon increasing the vibration amplitude (ξ{sub s} ∼ 10{sup −8} m), the heat transfer becomes more substantial due to the rapid bursting of vapor bubbles happening at the liquid-air interface as a consequence of capillary waves travelling in the thin liquid film between the vapor bubble and the air. Further increases then lead to rapid atomization that continues to enhance the heat transfer. An acoustic wave displacement amplitude on the order of 10{sup −8} m with 10{sup 6} Hz order frequencies is observed to produce an improvement of up to 50% reduction in the surface temperature over the case without acoustic excitation. 12. Acoustics, computers and measurements Truchard, James J. 2003-10-01 The human ear has created a high standard for the requirements of acoustical measurements. The transient nature of most acoustical signals has limited the success of traditional volt meters. Professor Hixson's pioneering work in electroacoustical measurements at ARL and The University of Texas helped set the stage for modern computer-based measurements. The tremendous performance of modern PCs and extensive libraries of signal processing functions in virtual instrumentation application software has revolutionized the way acoustical measurements are made. Today's analog to digital converters have up to 24 bits of resolution with a dynamic range of over 120 dB and a single PC processor can process 112 channels of FFTs at 4 kHz in real time. Wavelet technology further extends the capabilities for analyzing transients. The tools available for measurements in speech, electroacoustics, noise, and vibration represent some of the most advanced measurement tools available. During the last 50 years, Professor Hixson has helped drive this revolution from simple oscilloscope measurements to the modern high performance computer-based measurements. 13. Acoustically enhanced heat transport Ang, Kar M.; Yeo, Leslie Y.; Friend, James R.; Hung, Yew Mun; Tan, Ming K. 2016-01-01 We investigate the enhancement of heat transfer in the nucleate boiling regime by inducing high frequency acoustic waves (f ˜ 106 Hz) on the heated surface. In the experiments, liquid droplets (deionized water) are dispensed directly onto a heated, vibrating substrate. At lower vibration amplitudes (ξs ˜ 10-9 m), the improved heat transfer is mainly due to the detachment of vapor bubbles from the heated surface and the induced thermal mixing. Upon increasing the vibration amplitude (ξs ˜ 10-8 m), the heat transfer becomes more substantial due to the rapid bursting of vapor bubbles happening at the liquid-air interface as a consequence of capillary waves travelling in the thin liquid film between the vapor bubble and the air. Further increases then lead to rapid atomization that continues to enhance the heat transfer. An acoustic wave displacement amplitude on the order of 10-8 m with 106 Hz order frequencies is observed to produce an improvement of up to 50% reduction in the surface temperature over the case without acoustic excitation. 14. Contributions to multivariate analysis with applications in marketing Perlo-ten Kleij, Frederieke van 2004-01-01 Dit proefschrift behandelt een aantal onderwerpen uit de multivariate analyse, waarbij het begrip ‘multivariate analyse’ ruim moet worden ge¨ınterpreteerd. Naast onderwerpen uit de multivariate statistiek in enge zin, besteden we ook aandacht aan matrixrekening, ‘sum-constrained linear models’, mark 15. Approaches to sample size determination for multivariate data Saccenti, Edoardo; Timmerman, Marieke E. 2016-01-01 Sample size determination is a fundamental step in the design of experiments. Methods for sample size determination are abundant for univariate analysis methods, but scarce in the multivariate case. Omics data are multivariate in nature and are commonly investigated using multivariate statistical 16. Finer discrimination of brain activation with local multivariate distance 2007-01-01 The organization of human brain function is diverse on different spatial scales.Various cognitive states are alwavs represented as distinct activity patterns across the specific brain region on fine scales.Conventional univariate analysis of functional MRI data seeks to determine how a particular cognitive state is encoded in brain activity by analyzing each voxel separately without considering the fine-scale patterns information contained in the local brain regions.In this paper,a local multivariate distance mapping(LMDM)technique is proposed to detect the brain activation and to map the fine-scale brain activity patterns.LMDM directly represents the local brain activity with the patterns across multiple voxels rather than individual voxels,and it employs the multivariate distance between different patterns to discriminate the brain state on fine scales.Experiments with simulated and real fMRI data demonstrate that LMDM technique can dramatically increase the sensitivity of the detection for the fine-scale brain activity pettems which contain the subtle information of the experimental conditions. 17. Computational acoustic modeling of cetacean vocalizations Gurevich, Michael Dixon A framework for computational acoustic modeling of hypothetical vocal production mechanisms in cetaceans is presented. As a specific example, a model of a proposed source in the larynx of odontocetes is developed. Whales and dolphins generate a broad range of vocal sounds, but the exact mechanisms they use are not conclusively understood. In the fifty years since it has become widely accepted that whales can and do make sound, how they do so has remained particularly confounding. Cetaceans' highly divergent respiratory anatomy, along with the difficulty of internal observation during vocalization have contributed to this uncertainty. A variety of acoustical, morphological, ethological and physiological evidence has led to conflicting and often disputed theories of the locations and mechanisms of cetaceans' sound sources. Computational acoustic modeling has been used to create real-time parametric models of musical instruments and the human voice. These techniques can be applied to cetacean vocalizations to help better understand the nature and function of these sounds. Extensive studies of odontocete laryngeal morphology have revealed vocal folds that are consistently similar to a known but poorly understood acoustic source, the ribbon reed. A parametric computational model of the ribbon reed is developed, based on simplified geometrical, mechanical and fluid models drawn from the human voice literature. The physical parameters of the ribbon reed model are then adapted to those of the odontocete larynx. With reasonable estimates of real physical parameters, both the ribbon reed and odontocete larynx models produce sounds that are perceptually similar to their real-world counterparts, and both respond realistically under varying control conditions. Comparisons of acoustic features of the real-world and synthetic systems show a number of consistencies. While this does not on its own prove that either model is conclusively an accurate description of the source, it 18. High-Frequency Seafloor Acoustics Jackson, Darrell R 2007-01-01 High-Frequency Seafloor Acoustics is the first book in a new series sponsored by the Office of Naval Research on the latest research in underwater acoustics. This exciting new title provides ready access to experimental data, theory, and models relevant to high-frequency seafloor acoustics and will be of interest to sonar engineers and researchers working in underwater acoustics. The physical characteristics of the seafloor affecting acoustic propagation and scattering are covered, including physical and geoacoustic properties and surface roughness. Current theories for acoustic propagation in sediments are presented along with corresponding models for reflection, scattering, and seafloor penetration. The main text is backed up by an extensive bibliography and technical appendices. 19. Latest Trends in Acoustic Sensing Cinzia Caliendo 2014-03-01 Full Text Available Acoustics-based methods offer a powerful tool for sensing applications. Acoustic sensors can be applied in many fields ranging from materials characterization, structural health monitoring, acoustic imaging, defect characterization, etc., to name just a few. A proper selection of the acoustic wave frequency over a wide spectrum that extends from infrasound (<20 Hz up to ultrasound (in the GHz–band, together with a number of different propagating modes, including bulk longitudinal and shear waves, surface waves, plate modes, etc., allow acoustic tools to be successfully applied to the characterization of gaseous, solid and liquid environments. The purpose of this special issue is to provide an overview of the research trends in acoustic wave sensing through some cases that are representative of specific applications in different sensing fields. 20. Fundamentals of Shallow Water Acoustics Katsnelson, Boris; Lynch, James 2012-01-01 Shallow water acoustics (SWA), the study of how low and medium frequency sound propagates and scatters on the continental shelves of the world's oceans, has both technical interest and a large number of practical applications. Technically, shallow water poses an interesting medium for the study of acoustic scattering, inverse theory, and propagation physics in a complicated oceanic waveguide. Practically, shallow water acoustics has interest for geophysical exploration, marine mammal studies, and naval applications. Additionally, one notes the very interdisciplinary nature of shallow water acoustics, including acoustical physics, physical oceanography, marine geology, and marine biology. In this specialized volume, the authors, all of whom have extensive at-sea experience in U.S. and Russian research efforts, have tried to summarize the main experimental, theoretical, and computational results in shallow water acoustics, with an emphasis on providing physical insight into the topics presented. 1. Multivariable adaptive control of bio process Maher, M.; Bahhou, B.; Roux, G. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France); Maher, M. [Faculte des Sciences, Rabat (Morocco). Lab. de Physique 1995-12-31 This paper presents a multivariable adaptive control of a continuous-flow fermentation process for the alcohol production. The linear quadratic control strategy is used for the regulation of substrate and ethanol concentrations in the bioreactor. The control inputs are the dilution rate and the influent substrate concentration. A robust identification algorithm is used for the on-line estimation of linear MIMO model`s parameters. Experimental results of a pilot-plant fermenter application are reported and show the control performances. (authors) 8 refs. 2. Multivariate Generalized Linear Mixed Models Using R Berridge, Damon M 2011-01-01 To provide researchers with the ability to analyze large and complex data sets using robust models, this book presents a unified framework for a broad class of models that can be applied using a dedicated R package (Sabre). The first five chapters cover the analysis of multilevel models using univariate generalized linear mixed models (GLMMs). The next few chapters extend to multivariate GLMMs and the last chapters address more specialized topics, such as parallel computing for large-scale analyses. Each chapter includes many real-world examples implemented using Sabre as well as exercises and 3. Multivariate Process Control with Autocorrelated Data Kulahci, Murat 2011-01-01 As sensor and computer technology continues to improve, it becomes a normal occurrence that we confront with high dimensional data sets. As in many areas of industrial statistics, this brings forth various challenges in statistical process control and monitoring. This new high dimensional data...... often exhibit not only cross-‐correlation among the quality characteristics of interest but also serial dependence as a consequence of high sampling frequency and system dynamics. In practice, the most common method of monitoring multivariate data is through what is called the Hotelling’s T2 statistic... 4. Multivariate linear models and repeated measurements revisited Dalgaard, Peter 2009-01-01 Methods for generalized analysis of variance based on multivariate normal theory have been known for many years. In a repeated measurements context, it is most often of interest to consider transformed responses, typically within-subject contrasts or averages. Efficiency considerations leads...... to sphericity assumptions, use of F tests and the Greenhouse-Geisser and Huynh-Feldt adjustments to compensate for deviations from sphericity. During a recent implementation of such methods in the R language, the general structure of such transformations was reconsidered, leading to a flexible specification... 5. Modelling and Forecasting Multivariate Realized Volatility Chiriac, Roxana; Voev, Valeri This paper proposes a methodology for modelling time series of realized covariance matrices in order to forecast multivariate risks. The approach allows for flexible dynamic dependence patterns and guarantees positive definiteness of the resulting forecasts without imposing parameter restrictions....... We provide an empirical application of the model, in which we show by means of stochastic dominance tests that the returns from an optimal portfolio based on the model's forecasts second-order dominate returns of portfolios optimized on the basis of traditional MGARCH models. This result implies... 6. New multivariable capabilities of the INCA program Bauer, Frank H.; Downing, John P.; Thorpe, Christopher J. 1989-01-01 The INteractive Controls Analysis (INCA) program was developed at NASA's Goddard Space Flight Center to provide a user friendly, efficient environment for the design and analysis of control systems, specifically spacecraft control systems. Since its inception, INCA has found extensive use in the design, development, and analysis of control systems for spacecraft, instruments, robotics, and pointing systems. The (INCA) program was initially developed as a comprehensive classical design analysis tool for small and large order control systems. The latest version of INCA, expected to be released in February of 1990, was expanded to include the capability to perform multivariable controls analysis and design. 7. "Ranking Multivariate GARCH Models by Problem Dimension" Caporin, Massimiliano; McAleer, Michael 2010-01-01 textabstractIn the last 15 years, several Multivariate GARCH (MGARCH) models have appeared in the literature. The two most widely known and used are the Scalar BEKK model of Engle and Kroner (1995) and Ding and Engle (2001), and the DCC model of Engle (2002). Some recent research has begun to examine MGARCH specifications in terms of their out-of-sample forecasting performance. In this paper, we provide an empirical comparison of a set of MGARCH models, namely BEKK, DCC, Corrected DCC (cDCC) ... 8. Topics in multivariate approximation and interpolation Jetter, Kurt 2005-01-01 This book is a collection of eleven articles, written by leading experts and dealing with special topics in Multivariate Approximation and Interpolation. The material discussed here has far-reaching applications in many areas of Applied Mathematics, such as in Computer Aided Geometric Design, in Mathematical Modelling, in Signal and Image Processing and in Machine Learning, to mention a few. The book aims at giving a comprehensive information leading the reader from the fundamental notions and results of each field to the forefront of research. It is an ideal and up-to-date introduction for gr 9. Fast Algorithm of Multivariable Generalized Predictive Control Jin,Yuanyu; Pang,Zhonghua; Cui,Hong 2005-01-01 To avoid the shortcoming of the traditional (previous)generalized predictive control (GPC) algorithms, too large amounts of computation, a fast algorithm of multivariable generalized predictive control is presented in which only the current control actions are computed exactly on line and the rest (the future control actions) are approximately done off line. The algorithm is simple and can be used in the arbitary-dimension input arbitary-dimension output (ADIADO) linear systems. Because it dose not need solving Diophantine equation and reduces the dimension of the inverse matrix, it decreases largely the computational burden. Finally, simulation results show that the presented algorithm is effective and practicable. 10. Multivariate postprocessing techniques for probabilistic hydrological forecasting Hemri, Stephan; Lisniak, Dmytro; Klein, Bastian 2016-04-01 Hydrologic ensemble forecasts driven by atmospheric ensemble prediction systems need statistical postprocessing in order to account for systematic errors in terms of both mean and spread. Runoff is an inherently multivariate process with typical events lasting from hours in case of floods to weeks or even months in case of droughts. This calls for multivariate postprocessing techniques that yield well calibrated forecasts in univariate terms and ensure a realistic temporal dependence structure at the same time. To this end, the univariate ensemble model output statistics (EMOS; Gneiting et al., 2005) postprocessing method is combined with two different copula approaches that ensure multivariate calibration throughout the entire forecast horizon. These approaches comprise ensemble copula coupling (ECC; Schefzik et al., 2013), which preserves the dependence structure of the raw ensemble, and a Gaussian copula approach (GCA; Pinson and Girard, 2012), which estimates the temporal correlations from training observations. Both methods are tested in a case study covering three subcatchments of the river Rhine that represent different sizes and hydrological regimes: the Upper Rhine up to the gauge Maxau, the river Moselle up to the gauge Trier, and the river Lahn up to the gauge Kalkofen. The results indicate that both ECC and GCA are suitable for modelling the temporal dependences of probabilistic hydrologic forecasts (Hemri et al., 2015). References Gneiting, T., A. E. Raftery, A. H. Westveld, and T. Goldman (2005), Calibrated probabilistic forecasting using ensemble model output statistics and minimum CRPS estimation, Monthly Weather Review, 133(5), 1098-1118, DOI: 10.1175/MWR2904.1. Hemri, S., D. Lisniak, and B. Klein, Multivariate postprocessing techniques for probabilistic hydrological forecasting, Water Resources Research, 51(9), 7436-7451, DOI: 10.1002/2014WR016473. Pinson, P., and R. Girard (2012), Evaluating the quality of scenarios of short-term wind power 11. COSIMA data analysis using multivariate techniques J. Silén 2014-08-01 Full Text Available We describe how to use multivariate analysis of complex TOF-SIMS spectra introducing the method of random projections. The technique allows us to do full clustering and classification of the measured mass spectra. In this paper we use the tool for classification purposes. The presentation describes calibration experiments of 19 minerals on Ag and Au substrates using positive mode ion spectra. The discrimination between individual minerals gives a crossvalidation Cohen κ for classification of typically about 80%. We intend to use the method as a fast tool to deduce a qualitative similarity of measurements. 12. Detecting Positive Correlations in a Multivariate Sample Castro, Ery Arias; Lugosi, Gábor 2012-01-01 We consider the problem of testing whether a correlation matrix of a multivariate normal population is the identity matrix. We focus on sparse classes of alternatives where only a few entries are nonzero and, in fact, positive. We derive a general lower bound applicable to various classes and study the performance of some near-optimal tests. We pay special attention to computational feasibility and construct near-optimal tests that can be computed efficiently. Finally, we apply our results to prove new lower bounds for the clique number of high-dimensional random geometric graphs. 13. Multivariable dynamic calculus on time scales Bohner, Martin 2016-01-01 This book offers the reader an overview of recent developments of multivariable dynamic calculus on time scales, taking readers beyond the traditional calculus texts. Covering topics from parameter-dependent integrals to partial differentiation on time scales, the book’s nine pedagogically oriented chapters provide a pathway to this active area of research that will appeal to students and researchers in mathematics and the physical sciences. The authors present a clear and well-organized treatment of the concept behind the mathematics and solution techniques, including many practical examples and exercises. 14. Multivariate Analysis for the Processing of Signals Beattie J.R. 2014-01-01 Full Text Available Real-world experiments are becoming increasingly more complex, needing techniques capable of tracking this complexity. Signal based measurements are often used to capture this complexity, where a signal is a record of a sample’s response to a parameter (e.g. time, displacement, voltage, wavelength that is varied over a range of values. In signals the responses at each value of the varied parameter are related to each other, depending on the composition or state sample being measured. Since signals contain multiple information points, they have rich information content but are generally complex to comprehend. Multivariate Analysis (MA has profoundly transformed their analysis by allowing gross simplification of the tangled web of variation. In addition MA has also provided the advantage of being much more robust to the influence of noise than univariate methods of analysis. In recent years, there has been a growing awareness that the nature of the multivariate methods allows exploitation of its benefits for purposes other than data analysis, such as pre-processing of signals with the aim of eliminating irrelevant variations prior to analysis of the signal of interest. It has been shown that exploiting multivariate data reduction in an appropriate way can allow high fidelity denoising (removal of irreproducible non-signals, consistent and reproducible noise-insensitive correction of baseline distortions (removal of reproducible non-signals, accurate elimination of interfering signals (removal of reproducible but unwanted signals and the standardisation of signal amplitude fluctuations. At present, the field is relatively small but the possibilities for much wider application are considerable. Where signal properties are suitable for MA (such as the signal being stationary along the x-axis, these signal based corrections have the potential to be highly reproducible, and highly adaptable and are applicable in situations where the data is noisy or 15. Fictitious domain method for acoustic waves through a granular suspension of movable rigid spheres Imbert, David; McNamara, Sean; Le Gonidec, Yves 2015-01-01 International audience; We develop a model to couple acoustic waves and the motion of rigid movable grains in a submerged suspension. To do so, we use the fictitious domain method based on distributed Lagrange multipliers to enforce the natural jump condition of the wave equation and a rigidity constraint. One can then model the granular medium with “Molecular Dynamics” or related methods. Both dynamic and acoustic numerical results are compared with analytic solutions of acoustics and an est... 16. Receptivity of a Cryogenic Coaxial Gas-Liquid Jet to Acoustic Disturbances 2014-06-01 in the inner jet and cooled helium in the outer annular jet to represent the nominal fluid dynamical conditions of an oxygen/hydrogen liquid rocket...acoustic disturbances. The shear coaxial jet flow employed liquid nitrogen in the inner jet and cooled helium in the outer annular jet to represent...shape, and the maximum acoustic velocity magnitude is estimated from the linear acoustics equation, c pu cρ ′ =′ (1) where u’ is the magnitude 17. Acoustical studies on corrugated tubes Balaguru, Rajavel Corrugated tubes and pipes offer greater global flexibility combined with local rigidity. They are used in numerous engineering applications such as vacuum cleaner hosing, air conditioning systems of aircraft and automobiles, HVAC control systems of heating ducts in buildings, compact heat exchangers, medical equipment and offshore gas and oil transportation flexible riser pipelines. Recently there has been a renewed research interest in analyzing the flow through a corrugated tube to understand the underlying mechanism of so called whistling, although the whistling in such a tube was identified in early twentieth century. The phenomenon of whistling in a corrugated tube is interesting because an airflow through a smooth walled tube of similar dimensions will not generate any whistling tones. Study of whistling in corrugated tubes is important because, it not only causes an undesirable noise problem but also results in flow-acoustic coupling. Such a coupling can cause significant structural vibrations due to flow-acoustic-structure interaction. This interaction would cause flow-induced vibrations that could result in severe damage to mechanical systems having corrugated tubes. In this research work, sound generation (whistling) in corrugated tubes due to airflow is analyzed using experimental as well as Computational Fluid Dynamics-Large Eddy Simulation (CFD-LES) techniques. Sound generation mechanisms resulting in whistling have been investigated. The whistling in terms of frequencies and sound pressure levels for different flow velocities are studied. The analytical and experimental studies are carried out to understand the influence of various parameters of corrugated tubes such as cavity length, cavity width, cavity depth, pitch, Reynolds numbers and number of corrugations. The results indicate that there is a good agreement between theoretically calculated, computationally predicted and experimentally measured whistling frequencies and sound pressure levels 18. ANALYSIS ON ACOUSTICAL SCATTERING BY A CRACKED ELASTIC STRUCTURE ZhongWeffang; WuYongdong; WuGuorong; LiangYide 2003-01-01 The acoustical scattering by a cracked elastic structure is studied. The mixed method of boundary element and fractal finite element is adopted to solve the cracked structure-acoustic coupling problem. The fractal two-level finite element method is employed for the cracked structure, which can reduce the degree of freedoms (DOFs) greatly, and the boundary element method is used for the exterior acoustic field which can automatically satisfy Sommerfeld's radiation condition. Numerical examples show that the resonance frequency is lower with the crack's depth increase, and that the effect on the acoustical field by the crack is particularly pronounced in the vicinity of the crack tip. This mixed method of boundary element and finite element is effective in solving the scattering problem by a cracked structure. 19. An effective absorbing boundary algorithm for acoustical wave propagator 2007-01-01 In this paper, Berenger's perfectly matched layer (PML) absorbing boundary condition for electromagnetic waves is introduced as the truncation area of the computational domain to absorb one-dimensional acoustic wave for the scheme of acoustical wave propagator (AWP). To guarantee the efficiency of the AWP algorithm, a regulated propagator matrix is derived in the PML medium.Numerical simulations of a Gaussian wave packet propagating in one-dimensional duct are carried out to illustraze the efficiency of the combination of PML and AWP. Compared with the traditional smoothing truncation windows technique of AWP, this scheme shows high computational accuracy in absorbing acoustic wave when the acoustical wave arrives at the computational edges. Optimal coefficients of the PML configurations are also discussed. 20. Ion-acoustic cnoidal waves in a quantum plasma Mahmood, Shahzad 2016-01-01 Nonlinear ion-acoustic cnoidal wave structures are studied in an unmagnetized quantum plasma. Using the reductive perturbation method, a Korteweg-de Vries equation is derived for appropriate boundary conditions and nonlinear periodic wave solutions are obtained. The corresponding analytical solution and numerical plots of the ion-acoustic cnoidal waves and solitons in the phase plane are presented using the Sagdeev pseudo-potential approach. The variations in the nonlinear potential of the ion-acoustic cnoidal waves are studied at different values of quantum parameterH_{e}$which is the ratio of electron plasmon energy to electron Fermi energy defined for degenerate electrons. It is found that both compressive and rarefactive ion-acoustic cnoidal wave structures are formed depending on the value of the quantum parameter. The dependence of the wavelength and frequency on nonlinear wave amplitude is also presented. 1. Spacecraft Internal Acoustic Environment Modeling Chu, S. Reynold; Allen, Chris 2009-01-01 The objective of the project is to develop an acoustic modeling capability, based on commercial off-the-shelf software, to be used as a tool for oversight of the future manned Constellation vehicles. The use of such a model will help ensure compliance with acoustic requirements. Also, this project includes modeling validation and development feedback via building physical mockups and conducting acoustic measurements to compare with the predictions. 2. Acoustic Imaging of Combustion Noise Ramohalli, K. N.; Seshan, P. K. 1984-01-01 Elliposidal acoustic mirror used to measure sound emitted at discrete points in burning turbulent jets. Mirror deemphasizes sources close to target source and excludes sources far from target. At acoustic frequency of 20 kHz, mirror resolves sound from region 1.25 cm wide. Currently used by NASA for research on jet flames. Produces clearly identifiable and measurable variation of acoustic spectral intensities along length of flame. Utilized in variety of monitoring or control systems involving flames or other reacting flows. 3. Acoustic streaming with heat exchange Gubaidullin, A. A.; Pyatkova, A. V. 2016-10-01 Acoustic streaming in a cylindrical cavity with heat exchange is numerically investigated. The cavity is filled with air. The boundaries of the cavity are maintained at constant temperature. The features of acoustic streaming manifesting with the decrease in the frequency of vibration in comparison with the resonant frequency are determined. The influence of the nonlinearity of process on acoustic streaming is shown. The nonlinearity is caused by the increase of the vibration amplitude. 4. F100 Multivariable Control Synthesis Program. Computer Implementation of the F100 Multivariable Control Algorithm Soeder, J. F. 1983-01-01 As turbofan engines become more complex, the development of controls necessitate the use of multivariable control techniques. A control developed for the F100-PW-100(3) turbofan engine by using linear quadratic regulator theory and other modern multivariable control synthesis techniques is described. The assembly language implementation of this control on an SEL 810B minicomputer is described. This implementation was then evaluated by using a real-time hybrid simulation of the engine. The control software was modified to run with a real engine. These modifications, in the form of sensor and actuator failure checks and control executive sequencing, are discussed. Finally recommendations for control software implementations are presented. 5. Combined Environment Acoustic Chamber (CEAC) Federal Laboratory Consortium — Purpose: The CEAC imposes combined acoustic, thermal and mechanical loads on aerospace structures. The CEAC is employed to measure structural response and determine... 6. Acoustic Communications Measurement Systems (ACOMMS) Federal Laboratory Consortium — FUNCTION: Design and develop adaptive signal processing techniques to improve underwater acoustic communications and networking. Phase coherent and incoherent signal... 7. Interpretability of Multivariate Brain Maps in Linear Brain Decoding: Definition, and Heuristic Quantification in Multivariate Analysis of MEG Time-Locked Effects Kia, Seyed Mostafa; Vega Pons, Sandro; Weisz, Nathan; Passerini, Andrea 2017-01-01 Brain decoding is a popular multivariate approach for hypothesis testing in neuroimaging. Linear classifiers are widely employed in the brain decoding paradigm to discriminate among experimental conditions. Then, the derived linear weights are visualized in the form of multivariate brain maps to further study spatio-temporal patterns of underlying neural activities. It is well known that the brain maps derived from weights of linear classifiers are hard to interpret because of high correlations between predictors, low signal to noise ratios, and the high dimensionality of neuroimaging data. Therefore, improving the interpretability of brain decoding approaches is of primary interest in many neuroimaging studies. Despite extensive studies of this type, at present, there is no formal definition for interpretability of multivariate brain maps. As a consequence, there is no quantitative measure for evaluating the interpretability of different brain decoding methods. In this paper, first, we present a theoretical definition of interpretability in brain decoding; we show that the interpretability of multivariate brain maps can be decomposed into their reproducibility and representativeness. Second, as an application of the proposed definition, we exemplify a heuristic for approximating the interpretability in multivariate analysis of evoked magnetoencephalography (MEG) responses. Third, we propose to combine the approximated interpretability and the generalization performance of the brain decoding into a new multi-objective criterion for model selection. Our results, for the simulated and real MEG data, show that optimizing the hyper-parameters of the regularized linear classifier based on the proposed criterion results in more informative multivariate brain maps. More importantly, the presented definition provides the theoretical background for quantitative evaluation of interpretability, and hence, facilitates the development of more effective brain decoding algorithms 8. Augmented Classical Least Squares Multivariate Spectral Analysis Haaland, David M. (Albuquerque, NM); Melgaard, David K. (Albuquerque, NM) 2005-07-26 A method of multivariate spectral analysis, termed augmented classical least squares (ACLS), provides an improved CLS calibration model when unmodeled sources of spectral variation are contained in a calibration sample set. The ACLS methods use information derived from component or spectral residuals during the CLS calibration to provide an improved calibration-augmented CLS model. The ACLS methods are based on CLS so that they retain the qualitative benefits of CLS, yet they have the flexibility of PLS and other hybrid techniques in that they can define a prediction model even with unmodeled sources of spectral variation that are not explicitly included in the calibration model. The unmodeled sources of spectral variation may be unknown constituents, constituents with unknown concentrations, nonlinear responses, non-uniform and correlated errors, or other sources of spectral variation that are present in the calibration sample spectra. Also, since the various ACLS methods are based on CLS, they can incorporate the new prediction-augmented CLS (PACLS) method of updating the prediction model for new sources of spectral variation contained in the prediction sample set without having to return to the calibration process. The ACLS methods can also be applied to alternating least squares models. The ACLS methods can be applied to all types of multivariate data. 9. Augmented Classical Least Squares Multivariate Spectral Analysis Haaland, David M. (Albuquerque, NM); Melgaard, David K. (Albuquerque, NM) 2005-01-11 A method of multivariate spectral analysis, termed augmented classical least squares (ACLS), provides an improved CLS calibration model when unmodeled sources of spectral variation are contained in a calibration sample set. The ACLS methods use information derived from component or spectral residuals during the CLS calibration to provide an improved calibration-augmented CLS model. The ACLS methods are based on CLS so that they retain the qualitative benefits of CLS, yet they have the flexibility of PLS and other hybrid techniques in that they can define a prediction model even with unmodeled sources of spectral variation that are not explicitly included in the calibration model. The unmodeled sources of spectral variation may be unknown constituents, constituents with unknown concentrations, nonlinear responses, non-uniform and correlated errors, or other sources of spectral variation that are present in the calibration sample spectra. Also, since the various ACLS methods are based on CLS, they can incorporate the new prediction-augmented CLS (PACLS) method of updating the prediction model for new sources of spectral variation contained in the prediction sample set without having to return to the calibration process. The ACLS methods can also be applied to alternating least squares models. The ACLS methods can be applied to all types of multivariate data. 10. Peramalan Multivariate untuk Menentukan Harga Emas Global David Christian 2016-12-01 Full Text Available Gold is one of the most enticing commodities and a very popular way of investing. Gold’s price is allegedly influenced by another factors such as US Dollar, oil’s price, inflation rate, and stock exchange so that its model is not only affected by its value. The aim of this research is to determine the best forecasting model and influencing factors to gold’s price. This research reviews the univariate modeling as a benchmark and comparison to the multivariate one. Univariate time series is modeled using the ARIMA model which indicates that the fluctuation of the gold prices are following the white noise. Gold’s multivariate modeling is built using the Vector Error Correction Model with oil’s price, US Dollar and Dow Jones indices, and inflation rate as its predictors. Research’s result shows that the VECM model has been able to model the gold’s price well and all factors investigated are influencing gold’s price. US Dollar and oil’s price are negatively correlated with gold’s price as the inflation rate is positively correlated. Dow Jones Index is positively correlated with gold’s price only at its first two periods 11. Multivariate intralocus sexual conflict in seed beetles. Berger, David; Berg, Elena C; Widegren, William; Arnqvist, Göran; Maklakov, Alexei A 2014-12-01 Intralocus sexual conflict (IaSC) is pervasive because males and females experience differences in selection but share much of the same genome. Traits with integrated genetic architecture should be reservoirs of sexually antagonistic genetic variation for fitness, but explorations of multivariate IaSC are scarce. Previously, we showed that upward artificial selection on male life span decreased male fitness but increased female fitness compared with downward selection in the seed beetle Callosobruchus maculatus. Here, we use these selection lines to investigate sex-specific evolution of four functionally integrated traits (metabolic rate, locomotor activity, body mass, and life span) that collectively define a sexually dimorphic life-history syndrome in many species. Male-limited selection for short life span led to correlated evolution in females toward a more male-like multivariate phenotype. Conversely, males selected for long life span became more female-like, implying that IaSC results from genetic integration of this suite of traits. However, while life span, metabolism, and body mass showed correlated evolution in the sexes, activity did not evolve in males but, surprisingly, did so in females. This led to sexual monomorphism in locomotor activity in short-life lines associated with detrimental effects in females. Our results thus support the general tenet that widespread pleiotropy generates IaSC despite sex-specific genetic architecture. 12. Adaptable Multivariate Calibration Models for Spectral Applications THOMAS,EDWARD V. 1999-12-20 Multivariate calibration techniques have been used in a wide variety of spectroscopic situations. In many of these situations spectral variation can be partitioned into meaningful classes. For example, suppose that multiple spectra are obtained from each of a number of different objects wherein the level of the analyte of interest varies within each object over time. In such situations the total spectral variation observed across all measurements has two distinct general sources of variation: intra-object and inter-object. One might want to develop a global multivariate calibration model that predicts the analyte of interest accurately both within and across objects, including new objects not involved in developing the calibration model. However, this goal might be hard to realize if the inter-object spectral variation is complex and difficult to model. If the intra-object spectral variation is consistent across objects, an effective alternative approach might be to develop a generic intra-object model that can be adapted to each object separately. This paper contains recommendations for experimental protocols and data analysis in such situations. The approach is illustrated with an example involving the noninvasive measurement of glucose using near-infrared reflectance spectroscopy. Extensions to calibration maintenance and calibration transfer are discussed. 13. Do We Really Need Both BEKK and DCC? A Tale of Two Multivariate GARCH Models M. Caporin (Massimiliano); M.J. McAleer (Michael) 2010-01-01 textabstractThe management and monitoring of very large portfolios of financial assets are routine for many individuals and organizations. The two most widely used models of conditional covariances and correlations in the class of multivariate GARCH models are BEKK and DCC. It is well known that BEK 14. STRONGLY CONSISTENT ESTIMATION FOR A MULTIVARIATE LINEAR RELATIONSHIP MODEL WITH ESTIMATED COVARIANCES MATRIX Yee LEUNG; WU Kefa; DONG Tianxin 2001-01-01 In this paper, a multivariate linear functional relationship model, where the covariance matrix of the observational errors is not restricted, is considered. The parameter estimation of this model is discussed. The estimators are shown to be a strongly consistent estimation under some mild conditions on the incidental parameters. 15. Comparing the accuracy of copula-based multivariate density forecasts in selected regions of support Diks, C.; Panchenko, V.; Sokolinskiy, O.; van Dijk, D. 2013-01-01 This paper develops a testing framework for comparing the predictive accuracy of copula-based multivariate density forecasts, focusing on a specific part of the joint distribution. The test is framed in the context of the Kullback-Leibler Information Criterion, but using (out-of-sample) conditional 16. A NEW METHOD FOR THE CONSTRUCTION OF MULTIVARIATE MINIMAL INTERPOLATION POLYNOMIAL Zhang Chuanlin 2001-01-01 The extended Hermite interpolation problem on segment points set over n-dimensional Euclidean space is cansidered. Based on the algorithm to com pute the Grobner basis of Ideal given by dual basis a new method to construct minimal multivariate polynomial which satis fies the interpolation conditions is given. 17. Study of acoustic resonance of cascades Honjo, M.; Tominaga, T. Discrete sounds and vibrations from guide vanes due to acoustic resonance in the vane flow path, are experimentally investigated. Other causes of pure sounds in stationary vanes are considered, such as direct radiation from wake shedding vortices, bubble vortices or leading edges, and radial or axial modes of air columns. Two-dimensional cascade tests are performed under various conditions, and the data are compared with theoretical results of flat plate cascades. Three-dimensional ducted guide vane model tests are carried out to apply prototype guide vanes, and to confirm the resonance of the two-dimensional tests. Results show that frequency is more sensitive to chord length than pitch length, and the ratio of the fluctuation frequency to fluid sound velocity/pitch length is independent of the scale. Bubble vortices on concave surfaces or leading edges are not exciting sources; and under the limit of solidity, no exciting energy can generate acoustic resonance in correspondence to the mode. 18. Acoustic transparency and slow sound using detuned acoustic resonators Santillan, Arturo Orozco; Bozhevolnyi, Sergey I. 2011-01-01 We demonstrate that the phenomenon of acoustic transparency and slowsound propagation can be realized with detuned acoustic resonators (DAR), mimicking thereby the effect of electromagnetically induced transparency (EIT) in atomic physics. Sound propagation in a pipe with a series of side... 19. Kernel Multivariate Analysis Framework for Supervised Subspace Learning: A Tutorial on Linear and Kernel Multivariate Methods Arenas-Garcia, J.; Petersen, K.; Camps-Valls, G. 2013-01-01 sources become more common. A plethora of feature extraction methods are available in the literature collectively grouped under the field of multivariate analysis (MVA). This article provides a uniform treatment of several methods: principal component analysis (PCA), partial least squares (PLS), canonical... 20. Unsupervised classification of multivariate geostatistical data: Two algorithms Romary, Thomas; Ors, Fabien; Rivoirard, Jacques; Deraisme, Jacques 2015-12-01 With the increasing development of remote sensing platforms and the evolution of sampling facilities in mining and oil industry, spatial datasets are becoming increasingly large, inform a growing number of variables and cover wider and wider areas. Therefore, it is often necessary to split the domain of study to account for radically different behaviors of the natural phenomenon over the domain and to simplify the subsequent modeling step. The definition of these areas can be seen as a problem of unsupervised classification, or clustering, where we try to divide the domain into homogeneous domains with respect to the values taken by the variables in hand. The application of classical clustering methods, designed for independent observations, does not ensure the spatial coherence of the resulting classes. Image segmentation methods, based on e.g. Markov random fields, are not adapted to irregularly sampled data. Other existing approaches, based on mixtures of Gaussian random functions estimated via the expectation-maximization algorithm, are limited to reasonable sample sizes and a small number of variables. In this work, we propose two algorithms based on adaptations of classical algorithms to multivariate geostatistical data. Both algorithms are model free and can handle large volumes of multivariate, irregularly spaced data. The first one proceeds by agglomerative hierarchical clustering. The spatial coherence is ensured by a proximity condition imposed for two clusters to merge. This proximity condition relies on a graph organizing the data in the coordinates space. The hierarchical algorithm can then be seen as a graph-partitioning algorithm. Following this interpretation, a spatial version of the spectral clustering algorithm is also proposed. The performances of both algorithms are assessed on toy examples and a mining dataset. 1. Hierarchical Least Squares Identification and Its Convergence for Large Scale Multivariable Systems 丁锋; 丁韬 2002-01-01 The recursive least squares identification algorithm (RLS) for large scale multivariable systems requires a large amount of calculations, therefore, the RLS algorithm is difficult to implement on a computer. The computational load of estimation algorithms can be reduced using the hierarchical least squares identification algorithm (HLS) for large scale multivariable systems. The convergence analysis using the Martingale Convergence Theorem indicates that the parameter estimation error (PEE) given by the HLS algorithm is uniformly bounded without a persistent excitation signal and that the PEE consistently converges to zero for the persistent excitation condition. The HLS algorithm has a much lower computational load than the RLS algorithm. 2. Frequency steerable acoustic transducers Senesi, Matteo Structural health monitoring (SHM) is an active research area devoted to the assessment of the structural integrity of critical components of aerospace, civil and mechanical systems. Guided wave methods have been proposed for SHM of plate-like structures using permanently attached piezoelectric transducers, which generate and sense waves to evaluate the presence of damage. Effective interrogation of structural health is often facilitated by sensors and actuators with the ability to perform electronic, i.e. phased array, scanning. The objective of this research is to design an innovative directional piezoelectric transducer to be employed for the localization of broadband acoustic events, or for the generation of Lamb waves for active interrogation of structural health. The proposed Frequency Steerable Acoustic Transducers (FSATs) are characterized by a spatial arrangement of active material which leads to directional characteristics varying with frequency. Thus FSATs can be employed both for directional sensing and generation of guided waves without relying on phasing and control of a large number of channels. The analytical expression of the shape of the FSATs is obtained through a theoretical formulation for continuously distributed active material as part of a shaped piezoelectric device. The FSAT configurations analyzed in this work are a quadrilateral array and a geometry which corresponds to a spiral in the wavenumber domain. The quadrilateral array is experimentally validated, confirming the concept of frequency-dependent directionality. Its limited directivity is improved by the Wavenumber Spiral FSAT (WS-FSAT), which, instead, is characterized by a continuous frequency dependent directionality. Preliminary validations of the WS-FSAT, using a laser doppler vibrometer, are followed by the implementation of the WS-FSAT as a properly shaped piezo transducer. The prototype is first used for localization of acoustic broadband sources. Signal processing 3. Acoustic Mechanical Feedthroughs Sherrit, Stewart; Walkemeyer, Phillip; Bao, Xiaoqi; Bar-Cohen, Yoseph; Badescu, Mircea 2013-01-01 Electromagnetic motors can have problems when operating in extreme environments. In addition, if one needs to do mechanical work outside a structure, electrical feedthroughs are required to transport the electric power to drive the motor. In this paper, we present designs for driving rotary and linear motors by pumping stress waves across a structure or barrier. We accomplish this by designing a piezoelectric actuator on one side of the structure and a resonance structure that is matched to the piezoelectric resonance of the actuator on the other side. Typically, piezoelectric motors can be designed with high torques and lower speeds without the need for gears. One can also use other actuation materials such as electrostrictive, or magnetostrictive materials in a benign environment and transmit the power in acoustic form as a stress wave and actuate mechanisms that are external to the benign environment. This technology removes the need to perforate a structure and allows work to be done directly on the other side of a structure without the use of electrical feedthroughs, which can weaken the structure, pipe, or vessel. Acoustic energy is pumped as a stress wave at a set frequency or range of frequencies to produce rotary or linear motion in a structure. This method of transferring useful mechanical work across solid barriers by pumping acoustic energy through a resonant structure features the ability to transfer work (rotary or linear motion) across pressure or thermal barriers, or in a sterile environment, without generating contaminants. Reflectors in the wall of barriers can be designed to enhance the efficiency of the energy/power transmission. The method features the ability to produce a bi-directional driving mechanism using higher-mode resonances. There are a variety of applications where the presence of a motor is complicated by thermal or chemical environments that would be hostile to the motor components and reduce life and, in some instances, not be 4. Taming Acoustic Cavitation Rivas, David Fernandez; Enriquez, Oscar R; Versluis, Michel; Prosperetti, Andrea; Gardeniers, Han; Lohse, Detlef 2012-01-01 In this fluid dynamics video we show acoustic cavitation occurring from pits etched on a silicon surface. By immersing the surface in a liquid, gas pockets are entrapped in the pits which upon ultrasonic insonation, are observed to shed cavitation bubbles. Modulating the driving pressure it is possible to induce different behaviours based on the force balance that determines the interaction among bubbles and the silicon surface. This system can be used for several applications like sonochemical water treatment, cleaning of surfaces with deposited materials such as biofilms. 5. Wind turbine acoustics Hubbard, Harvey H.; Shepherd, Kevin P. 1990-12-01 Available information on the physical characteristics of the noise generated by wind turbines is summarized, with example sound pressure time histories, narrow- and broadband frequency spectra, and noise radiation patterns. Reviewed are noise measurement standards, analysis technology, and a method of characterizing wind turbine noise. Prediction methods are given for both low-frequency rotational harmonics and broadband noise components. Also included are atmospheric propagation data showing the effects of distance and refraction by wind shear. Human perception thresholds, based on laboratory and field tests, are given. Building vibration analysis methods are summarized. The bibliography of this report lists technical publications on all aspects of wind turbine acoustics. 6. A Tourism Conditions Index C-L. Chang (Chia-Lin); H-K. Hsu (Hui-Kuang); M.J. McAleer (Michael) 2014-01-01 markdownabstract__Abstract__ This paper uses monthly data from April 2005 to August 2013 for Taiwan to propose a novel tourism indicator, namely the Tourism Conditions Index (TCI). TCI accounts for the spillover weights based on the Granger causality test and estimates of the multivariate BEKK mode 7. Development of radio acoustic sounding system (RASS) with Gadanki MST radar – first results T. V. Chandrasekhar Sarma; Narayana Rao, D.; Furumoto, J.; Tsuda, T. 2008-01-01 A high-power acoustic exciter was designed and developed for the Gadanki MST Radar to facilitate observations in the Radio Acoustic Sounding System (RASS) mode. Sweep range of acoustic signal frequencies was set to 94–125 Hz so as to satisfy Bragg matching condition for temperature range of −90°–40°C between surface and the tropopause (about 17 km). Raytracing of acoustic wave propagation was used to predict the antenna beam directions along which optimum RASS echoes could be ob... 8. Multi-frequency acoustic metasurface for extraordinary reflection and sound focusing Yi-Fan Zhu 2016-12-01 Full Text Available We theoretically and numerically present the design of multi-frequency acoustic metasurfaces (MFAMs with simple structure that can work not only at fundamental frequency, but also at their harmonic frequencies, which breaks the single frequency limitation in conventional resonance-based acoustic metasurfaces. The phase matched condition for achromatic manipulation is discussed. We demonstrate achromatic extraordinary reflection and sound focusing at 1700Hz, 3400Hz, and 5100Hz, that is, they have the same reflection direction and the same focusing position. This significant feature may pave the way to new type of acoustic metasurface, and will also extend acoustic metasurface applications to strongly nonlinear source cases. 9. Propagation of Ion Acoustic Perturbations Pécseli, Hans 1975-01-01 Equations describing the propagation of ion acoustic perturbations are considered, using the assumption that the electrons are Boltzman distributed and isothermal at all times. Quasi-neutrality is also considered.......Equations describing the propagation of ion acoustic perturbations are considered, using the assumption that the electrons are Boltzman distributed and isothermal at all times. Quasi-neutrality is also considered.... 10. Acoustic Center or Time Origin? Staffeldt, Henrik 1999-01-01 The paper discusses the acoustic center in relation to measurements of loudspeaker polar data. Also, it presents the related concept time origin and discusses the deviation that appears between positions of the acoustic center found by wavefront based and time based measuring methods.... 11. Generation of multivariate Hermite interpolating polynomials Tavares, Santiago Alves 2005-01-01 Generation of Multivariate Hermite Interpolating Polynomials advances the study of approximate solutions to partial differential equations by presenting a novel approach that employs Hermite interpolating polynomials and bysupplying algorithms useful in applying this approach.Organized into three sections, the book begins with a thorough examination of constrained numbers, which form the basis for constructing interpolating polynomials. The author develops their geometric representation in coordinate systems in several dimensions and presents generating algorithms for each level number. He then discusses their applications in computing the derivative of the product of functions of several variables and in the construction of expression for n-dimensional natural numbers. Section II focuses on the construction of Hermite interpolating polynomials, from their characterizing properties and generating algorithms to a graphical analysis of their behavior. The final section of the book is dedicated to the applicatio... 12. Multivariate Markov chain modeling for stock markets Maskawa, Jun-ichi 2003-06-01 We study a multivariate Markov chain model as a stochastic model of the price changes of portfolios in the framework of the mean field approximation. The time series of price changes are coded into the sequences of up and down spins according to their signs. We start with the discussion for small portfolios consisting of two stock issues. The generalization of our model to arbitrary size of portfolio is constructed by a recurrence relation. The resultant form of the joint probability of the stationary state coincides with Gibbs measure assigned to each configuration of spin glass model. Through the analysis of actual portfolios, it has been shown that the synchronization of the direction of the price changes is well described by the model. 13. Astrocladistics: Multivariate Evolutionary Analysis in Astrophysics Fraix-Burnet, Didier 2010-01-01 The Hubble tuning fork diagram, based on morphology and established in the 1930s, has always been the preferred scheme for classification of galaxies. However, the current large amount of data up to higher and higher redshifts asks for more sophisticated statistical approaches like multivariate analyses. Clustering analyses are still very confidential, and do not take into account the unavoidable characteristics in our Universe: evolution. Assuming branching evolution of galaxies as a 'transmission with modification', we have shown that the concepts and tools of phylogenetic systematics (cladistics) can be heuristically transposed to the case of galaxies. This approach that we call "astrocladistics", has now successfully been applied on several samples of galaxies and globular clusters. Maximum parsimony and distance-based approaches are the most popular methods to produce phylogenetic trees and, like most other studies, we had to discretize our variables. However, since astrophysical data are intrinsically c... 14. Control Configuration Selection for Multivariable Descriptor Systems Shaker, Hamid Reza; Stoustrup, Jakob 2012-01-01 is needed to be controlled, is either in the descriptor form or can be represented in the descriptor form. Singular systems and the differential algebraic equation (DAE) systems are among these systems. Descriptor systems appear in the variety of fields to describe the practical processes ranging from power...... systems, hydraulic systems to heat transfer, and chemical processes. The focus of this paper is on the problem of control configuration selection for multivariable descriptor systems. A gramian-based interaction measure for control configuration selection of such processes is described in this paper....... The proposed MIMO interaction measure is the extension of its gramian-based analogous counterpart, which has been proposed for the input–output pairing as well as for the controller architecture selection of the processes with the standard state-space form. The main advantage of this interaction measure... 15. Multivariate analysis applied to tomato hybrid production. Balasch, S; Nuez, F; Palomares, G; Cuartero, J 1984-11-01 Twenty characters were measured on 60 tomato varieties cultivated in the open-air and in polyethylene plastic-house. Data were analyzed by means of principal components, factorial discriminant methods, Mahalanobis D(2) distances and principal coordinate techniques. Factorial discriminant and Mahalanobis D(2) distances methods, both of which require collecting data plant by plant, lead to similar conclusions as the principal components method that only requires taking data by plots. Characters that make up the principal components in both environments studied are the same, although the relative importance of each one of them varies within the principal components. By combining information supplied by multivariate analysis with the inheritance mode of characters, crossings among cultivars can be experimented with that will produce heterotic hybrids showing characters within previously established limits. 16. Lectures in feedback design for multivariable systems Isidori, Alberto 2017-01-01 This book focuses on methods that relate, in one form or another, to the “small-gain theorem”. It is aimed at readers who are interested in learning methods for the design of feedback laws for linear and nonlinear multivariable systems in the presence of model uncertainties. With worked examples throughout, it includes both introductory material and more advanced topics. Divided into two parts, the first covers relevant aspects of linear-systems theory, the second, nonlinear theory. In order to deepen readers’ understanding, simpler single-input–single-output systems generally precede treatment of more complex multi-input–multi-output (MIMO) systems and linear systems precede nonlinear systems. This approach is used throughout, including in the final chapters, which explain the latest advanced ideas governing the stabilization, regulation, and tracking of nonlinear MIMO systems. Two major design problems are considered, both in the presence of model uncertainties: asymptotic stabilization with a “... 17. Generation of hierarchically correlated multivariate symbolic sequences Tumminello, Mi; Mantegna, R N 2008-01-01 We introduce an algorithm to generate multivariate series of symbols from a finite alphabet with a given hierarchical structure of similarities. The target hierarchical structure of similarities is arbitrary, for instance the one obtained by some hierarchical clustering procedure as applied to an empirical matrix of Hamming distances. The algorithm can be interpreted as the finite alphabet equivalent of the recently introduced hierarchically nested factor model (M. Tumminello et al. EPL 78 (3) 30006 (2007)). The algorithm is based on a generating mechanism that is different from the one used in the mutation rate approach. We apply the proposed methodology for investigating the relationship between the bootstrap value associated with a node of a phylogeny and the probability of finding that node in the true phylogeny. 18. International Conference on Measurement and Multivariate Analysis Baba, Yasumasa; Bozdogan, Hamparsum; Kanefuji, Koji; Measurement and Multivariate Analysis 2002-01-01 Diversity is characteristic of the information age and also of statistics. To date, the social sciences have contributed greatly to the development of handling data under the rubric of measurement, while the statistical sciences have made phenomenal advances in theory and algorithms. Measurement and Multivariate Analysis promotes an effective interplay between those two realms of research-diversity with unity. The union and the intersection of those two areas of interest are reflected in the papers in this book, drawn from an international conference in Banff, Canada, with participants from 15 countries. In five major categories - scaling, structural analysis, statistical inference, algorithms, and data analysis - readers will find a rich variety of topics of current interest in the extended statistical community. 19. Adaptive Rank Penalized Estimators in Multivariate Regression Bunea, Florentina; Wegkamp, Marten 2010-01-01 We introduce a new criterion, the Rank Selection Criterion (RSC), for selecting the optimal reduced rank estimator of the coefficient matrix in multivariate response regression models. The corresponding RSC estimator minimizes the Frobenius norm of the fit plus a regularization term proportional to the number of parameters in the reduced rank model. The rank of the RSC estimator provides a consistent estimator of the rank of the coefficient matrix. The consistency results are valid not only in the classic asymptotic regime, when the number of responses$n$and predictors$p$stays bounded, and the number of observations$m$grows, but also when either, or both,$n$and$p$grow, possibly much faster than$m\$. Our finite sample prediction and estimation performance bounds show that the RSC estimator achieves the optimal balance between the approximation error and the penalty term. Furthermore, our procedure has very low computational complexity, linear in the number of candidate models, making it particularly ...
20. A Gibbs Sampler for Multivariate Linear Regression
2015-01-01
Kelly (2007, hereafter K07) described an efficient algorithm, using Gibbs sampling, for performing linear regression in the fairly general case where non-zero measurement errors exist for both the covariates and response variables, where these measurements may be correlated (for the same data point), where the response variable is affected by intrinsic scatter in addition to measurement error, and where the prior distribution of covariates is modeled by a flexible mixture of Gaussians rather than assumed to be uniform. Here I extend the K07 algorithm in two ways. First, the procedure is generalized to the case of multiple response variables. Second, I describe how to model the prior distribution of covariates using a Dirichlet process, which can be thought of as a Gaussian mixture where the number of mixture components is learned from the data. I present an example of multivariate regression using the extended algorithm, namely fitting scaling relations of the gas mass, temperature, and luminosity of dynamica...
1. Exploration of new multivariate spectral calibration algorithms.
Van Benthem, Mark Hilary; Haaland, David Michael; Melgaard, David Kennett; Martin, Laura Elizabeth; Wehlburg, Christine Marie; Pell, Randy J. (The Dow Chemical Company, Midland, MI); Guenard, Robert D. (Merck & Co. Inc., West Point, PA)
2004-03-01
A variety of multivariate calibration algorithms for quantitative spectral analyses were investigated and compared, and new algorithms were developed in the course of this Laboratory Directed Research and Development project. We were able to demonstrate the ability of the hybrid classical least squares/partial least squares (CLSIPLS) calibration algorithms to maintain calibrations in the presence of spectrometer drift and to transfer calibrations between spectrometers from the same or different manufacturers. These methods were found to be as good or better in prediction ability as the commonly used partial least squares (PLS) method. We also present the theory for an entirely new class of algorithms labeled augmented classical least squares (ACLS) methods. New factor selection methods are developed and described for the ACLS algorithms. These factor selection methods are demonstrated using near-infrared spectra collected from a system of dilute aqueous solutions. The ACLS algorithm is also shown to provide improved ease of use and better prediction ability than PLS when transferring calibrations between near-infrared calibrations from the same manufacturer. Finally, simulations incorporating either ideal or realistic errors in the spectra were used to compare the prediction abilities of the new ACLS algorithm with that of PLS. We found that in the presence of realistic errors with non-uniform spectral error variance across spectral channels or with spectral errors correlated between frequency channels, ACLS methods generally out-performed the more commonly used PLS method. These results demonstrate the need for realistic error structure in simulations when the prediction abilities of various algorithms are compared. The combination of equal or superior prediction ability and the ease of use of the ACLS algorithms make the new ACLS methods the preferred algorithms to use for multivariate spectral calibrations.
2. Single-electron transport driven by surface acoustic waves: Moving quantum dots versus short barriers
Utko, Pawel; Hansen, Jørn Bindslev; Lindelof, Poul Erik;
2007-01-01
We have investigated the response of the acoustoelectric-current driven by a surface-acoustic wave through a quantum point contact in the closed-channel regime. Under proper conditions, the current develops plateaus at integer multiples of ef when the frequency f of the surface-acoustic wave or t...
3. Acoustic Absorption in Porous Materials
Kuczmarski, Maria A.; Johnston, James C.
2011-01-01
An understanding of both the areas of materials science and acoustics is necessary to successfully develop materials for acoustic absorption applications. This paper presents the basic knowledge and approaches for determining the acoustic performance of porous materials in a manner that will help materials researchers new to this area gain the understanding and skills necessary to make meaningful contributions to this field of study. Beginning with the basics and making as few assumptions as possible, this paper reviews relevant topics in the acoustic performance of porous materials, which are often used to make acoustic bulk absorbers, moving from the physics of sound wave interactions with porous materials to measurement techniques for flow resistivity, characteristic impedance, and wavenumber.
4. Synchronization of an Array of Miniature Acoustic Engines
Kwon, Young Sang; Symko, Orest G.
2004-03-01
In the development of miniature arrays of acoustic engines for energy conversion, phase-locking of the array ensemble was investigated. As the individual acoustic devices are independent resonant elements, maximum output can be achieved by a coherent summation of the elements of the array. They have small variations in resonant frequency and they have different phases as they are non-linear self-sustained oscillators and their phases depend on the initial conditions. The acoustic engines are based on thermoacoustics, where heat is converted to sound in a resonator by applying a temperature gradient across a stack of high surface area elements. In the experiments described here, the devices oscillate in the frequency range of 3 kHz and they are assembled into arrays of 5 elements and 9 elements. When the array is activated with heat, the acoustic power output is not coherent; it contains all sorts of beats and frequency mixtures produced by each independent oscillator. However, coherence is achieved by the introduction of a relatively weak signal from a separate resonator which phase-locks all the self-sustained acoustic oscillators and causes coherent summation of oscillations. Such approach provides a high intensity acoustic signal which can be used in energy conversion of heat to electricity.
5. Periodic Partial Extinction Regime in Acoustically Coupled Fuel Droplet Combustion
Plascencia Quiroz, Miguel; Bennewitz, John; Vargas, Andres; Sim, Hyung Sub; Smith, Owen; Karagozian, Ann
2016-11-01
This experimental study investigates the response of burning liquid fuel droplets exposed to standing acoustic waves, extending prior studies quantifying mean and temporal flame response to moderate acoustic excitation. This investigation explores alternative fuels exposed to a range of acoustic forcing conditions (frequencies and amplitudes), with a focus on ethanol and JP-8. Three fundamental flame regimes are observed: sustained oscillatory combustion, periodic partial extinction and reignition (PPER), and full extinction. Phase-locked OH* chemiluminescence imaging and local temporal pressure measurements allow quantification of the combustion-acoustic coupling through the local Rayleigh index G. As expected, PPER produces negative G values, despite having clear flame oscillations. PPER is observed to occur at low-frequency, high amplitude excitation, where the acoustic time scales are large compared with kinetic/reaction times scales for diffusion-limited combustion processes. These quantitative differences in behavior are determined to depend on localized fluid mechanical strain created by the acoustic excitation as well as reaction kinetics. Supported by AFOSR Grant FA9550-15-1-0339.
6. ACOUSTIC RADIATION ENERGY AT A VARIATION OF THE COMPOSITE MECHANICAL DESTRUCTION AREA
Sergii Filonenko
2016-06-01
Full Text Available Purpose: The technological parameters of composite materials machining and also cutting tool state determine deforming and destruction of their surface layers conditions. Change of this conditions results to appearance of miscellaneous defects, loss of quality and produced items reliability. Therefore, optimization, control, diagnosis and monitoring of composite materials machining technological parameters are directed on obtaining the items given quality. For the solution of these problems tasks carry out researches of technological processes with usage of different methods. One of such methods is the acoustic emission method. Methods: The simulation and analysis of acoustic radiation energy parameters is carried out at change of composite material machining depth for prevailing mechanical destruction its surface layer. Results: We showed that to composite material machining the acoustic radiation energy has continuous nature. The ascending of composite material machining depth results to increase of acoustic emission statistical energy parameters. The regularity of acoustic emission energy parameters change are obtained and described. Is showed, that acoustic radiation most sensing parameter is the acoustic emission signals energy average level dispersion. Discussion: The outcomes researches demonstrate regularity influencing of composite material machining depth on acoustic emission energy parameters. Thus the analysis of acoustic emission signals energy average level dispersion can be used at mining methods of diagnostic, monitoring and control of composite materials machining technological parameters.
7. On the graph-theoretical interpretation of Pearson correlations in a multivariate process and a novel partial correlation measure
Runge, Jakob
2013-01-01
The dependencies of the lagged (Pearson) correlation function on the coefficients of multivariate autoregressive models are interpreted in the framework of time series graphs. Time series graphs are related to the concept of Granger causality and encode the conditional independence structure of a multivariate process. The authors show that the complex dependencies of the Pearson correlation coefficient complicate an interpretation and propose a novel partial correlation measure with a straigh...
8. The cluster index of regularly varying sequences with applications to limit theory for functions of multivariate Markov chains
Mikosch, Thomas Valentin; Wintenberger, Olivier
2014-01-01
We introduce the cluster index of a multivariate stationary sequence and characterize the index in terms of the spectral tail process. This index plays a major role in limit theory for partial sums of sequences. We illustrate the use of the cluster index by characterizing infinite variance stable...... limit distributions and precise large deviation results for sums of multivariate functions acting on a stationary Markov chain under a drift condition....
9. Acoustics and Hearing
2008-01-01
When one listens to music at home, one would like to have an acoustic impression close to that of being in the concert hall. Until recently this meant elaborate multi-channelled sound systems with 5 or more speakers. But head-related stereophony achieves the surround-sound effect in living rooms with only two loudspeakers. By virtue of their slight directivity as well as an electronic filter the limitations previously common to two-speaker systems can be overcome and this holds for any arbitrary two-channel recording. The book also investigates the question of how a wide and diffuse sound image can arise in concert halls and shows that the quality of concert halls decisively depends on diffuse sound images arising in the onset of reverberation. For this purpose a strong onset of reverberation is modified in an anechoic chamber by electroacoustic means. Acoustics and Hearing proposes ideas concerning signal processing in the auditory system that explain the measured results and the resultant sound effects plea...
10. MEMS Based Acoustic Array
Sheplak, Mark (Inventor); Nishida, Toshikaza (Inventor); Humphreys, William M. (Inventor); Arnold, David P. (Inventor)
2006-01-01
Embodiments of the present invention described and shown in the specification aid drawings include a combination responsive to an acoustic wave that can be utilized as a dynamic pressure sensor. In one embodiment of the present invention, the combination has a substrate having a first surface and an opposite second surface, a microphone positioned on the first surface of the substrate and having an input and a first output and a second output, wherein the input receives a biased voltage, and the microphone generates an output signal responsive to the acoustic wave between the first output and the second output. The combination further has an amplifier positioned on the first surface of the substrate and having a first input and a second input and an output, wherein the first input of the amplifier is electrically coupled to the first output of the microphone and the second input of the amplifier is electrically coupled to the second output of the microphone for receiving the output sinual from the microphone. The amplifier is spaced from the microphone with a separation smaller than 0.5 mm.
11. Acoustic data transmission method
Duckworth, A.
1991-09-17
This patent describes a method for transmitting time line data through a drillstring having drill pipe sections connected end-to-end by joints from a first location below the surface of the earth to a second location at or near the surface of the earth, the length and cross-sectional area of the drill pipe sections being different from the length and cross-sectional area of the joints. It comprises generating acoustic data signals having a single frequency content in at least one passband of the drillstring; transmitting the data signals through the drillstring from either the first location to the second location or from the second location to the first location during a time period prior to the onset of reflective interference caused by the data signals reflecting from along the length of the drillstring, the time period being equal to or less than the time for the data signals to travel three lengths of the drillstring; stopping the transmission of data signals at the onset of the reflective interference and allowing the acoustic signals to substantially attenuate; and detecting the data signals at the respective first or second location.
12. ACOUSTIC EMISSION MONITORING FOR WIND TURBINE BLADE COMPOSITE MATERIAL UNDER COMPRESSIVE DAMAGE FAILURE CONDITION%风电叶片复合材料压缩损伤破坏声发射监测
周伟; 张晓霞; 韦子辉; 钟旸
2011-01-01
研究了风电叶片单向复合材料的压缩力学特性及其声发射响应特征.结果表明,复合材料的横向和纵向压缩力学性能及其声发射响应特性明显不同,纵向压缩强度、模量高,失效应变小,对应的声发射相对能量、幅度高,但撞击累积总数少.复合材料具有脆性破坏的特点,横向压缩以45°剪切失效为主,纵向压缩以层间劈裂为主.风电叶片复合材料压缩损伤破坏与声发射的相对能量、幅度、撞击等参量特征有关.%The compressive tests and acoustic emission (AE) response characteristics of wind turbine blade composite material were conducted.The results showed that transverse compressive properties and corresponding AE characteristics of composite material were different to longitudinal direction.High compressive strength, high modulus, low failure strain, high AE relative energy, high amplitude and less cumulative hits were obtained in longitudinal direction.Furthermore, composite specimens exhibited brittle characteristics.The main failure modes of transverse and longitudinal compression were 45° shear failure and layer splitting, respectively.The AE monitoring results such as energy, amplitude, hits and other parameters in compressive tests were useful for monitoring the damage development and failure of the specimen.
13. Triboelectrification-based organic film nanogenerator for acoustic energy harvesting and self-powered active acoustic sensing.
Yang, Jin; Chen, Jun; Liu, Ying; Yang, Weiqing; Su, Yuanjie; Wang, Zhong Lin
2014-03-25
As a vastly available energy source in our daily life, acoustic vibrations are usually taken as noise pollution with little use as a power source. In this work, we have developed a triboelectrification-based thin-film nanogenerator for harvesting acoustic energy from ambient environment. Structured using a polytetrafluoroethylene thin film and a holey aluminum film electrode under carefully designed straining conditions, the nanogenerator is capable of converting acoustic energy into electric energy via triboelectric transduction. With an acoustic sensitivity of 9.54 V Pa(-1) in a pressure range from 70 to 110 dB and a directivity angle of 52°, the nanogenerator produced a maximum electric power density of 60.2 mW m(-2), which directly lit 17 commercial light-emitting diodes (LEDs). Furthermore, the nanogenerator can also act as a self-powered active sensor for automatically detecting the location of an acoustic source with an error less than 7 cm. In addition, an array of devices with varying resonance frequencies was employed to widen the overall bandwidth from 10 to 1700 Hz, so that the nanogenerator was used as a superior self-powered microphone for sound recording. Our approach presents an adaptable, mobile, and cost-effective technology for harvesting acoustic energy from ambient environment, with applications in infrastructure monitoring, sensor networks, military surveillance, and environmental noise reduction.
14. Acoustic estimation of suspended sediment concentration
朱维庆; 朱敏; 周忠来; 潘锋; 霍其增; 张向军
2001-01-01
In this paper, the acoustic estimation of suspended sediment concentration is discussed and two estimation methods of suspended sediment concentration are presented. The first method is curve fitting method, in which, according to the acoustic backscattering theory we assume that the fit-ting factor K1 (r) between the concentration M(r) obtained by acoustic observation and the concentra-tion M0(r) obtained by sampling water is a high order power function of distance r. Using least-square algorithm, we can determine the coefficients of the high order power function by minimizing the differ-ence between M(r) and M0(r) in the whole water profile. To the absorption coefficient of sound due to the suspension in water we do not give constraint in the first method. The second method is recur-sive fitting method, in which we take M0(r) as the conditions of initialization and decision and give ra-tional constraints to some parameters. The recursive process is stable. We analyzed the two methods with a lot of experimental data. The analytical results show that the estimate error of the first method is less than that of the second method and the latter can not only estimate the concentration of suspended sediment but also give the absorption coefficient of sound. Good results have been obtained with the two methods.
15. Measuring acoustic emissions in an avalanche slope
Reiweger, Ingrid; Schweizer, Jürg
2014-05-01
Measurements of acoustic emissions are a common technique for monitoring damage and predicting imminent failure of a material. Within natural hazards it has already been used to successfully predict the break-off of a hanging glacier. To explore the applicability of the acoustic emission (AE) technique for avalanche prediction, we installed two acoustic sensors (with 30 kHz and 60 kHz resonance frequency) in an avalanche prone slope at the Mittelgrat in the Parsenn ski area above Davos, Switzerland. The slope is north-east facing, frequently wind loaded, and approximately 35° steep. The AE signals - in particular the event energy and waiting time distributions - were compared with slope stability. The latter was determined by observing avalanche activity. The results of two winter's measurements yielded that the exponent β of the inverse cumulative distribution of event energy showed a significant drop (from a value of 3.5 to roughly 2.5) at very unstable conditions, i.e. on the three days during our measurement periods when spontaneous avalanches released on our study slope.
16. Dynamics of acoustically levitated disk samples.
Xie, W J; Wei, B
2004-10-01
The acoustic levitation force on disk samples and the dynamics of large water drops in a planar standing wave are studied by solving the acoustic scattering problem through incorporating the boundary element method. The dependence of levitation force amplitude on the equivalent radius R of disks deviates seriously from the R3 law predicted by King's theory, and a larger force can be obtained for thin disks. When the disk aspect ratio gamma is larger than a critical value gamma(*) ( approximately 1.9 ) and the disk radius a is smaller than the critical value a(*) (gamma) , the levitation force per unit volume of the sample will increase with the enlargement of the disk. The acoustic levitation force on thin-disk samples ( gammafield for stable levitation of a large water drop is to adjust the reflector-emitter interval H slightly above the resonant interval H(n) . The simulation shows that the drop is flattened and the central parts of its top and bottom surface become concave with the increase of sound pressure level, which agrees with the experimental observation. The main frequencies of the shape oscillation under different sound pressures are slightly larger than the Rayleigh frequency because of the large shape deformation. The simulated translational frequencies of the vertical vibration under normal gravity condition agree with the theoretical analysis.
17. Quantifying acoustic damping using flame chemiluminescence
Boujo, E.; Denisov, A.; Schuermans, B.; Noiray, N.
2016-12-01
Thermoacoustic instabilities in gas turbines and aeroengine combustors falls within the category of complex systems. They can be described phenomenologically using nonlinear stochastic differential equations, which constitute the grounds for output-only model-based system identification. It has been shown recently that one can extract the governing parameters of the instabilities, namely the linear growth rate and the nonlinear component of the thermoacoustic feedback, using dynamic pressure time series only. This is highly relevant for practical systems, which cannot be actively controlled due to a lack of cost-effective actuators. The thermoacoustic stability is given by the linear growth rate, which results from the combination of the acoustic damping and the coherent feedback from the flame. In this paper, it is shown that it is possible to quantify the acoustic damping of the system, and thus to separate its contribution to the linear growth rate from the one of the flame. This is achieved by post-processing in a simple way simultaneously acquired chemiluminescence and acoustic pressure data. It provides an additional approach to further unravel from observed time series the key mechanisms governing the system dynamics. This straightforward method is illustrated here using experimental data from a combustion chamber operated at several linearly stable and unstable operating conditions.
18. Engineering acoustic lenses with help from evolution
Ha˚Kansson, Andreas; Sánchez-Dehesa, José; Sánchis, Lorenzo
2004-05-01
Optimization engineering through evolutionary algorithms have proven to be very efficient, especially in hard problems containing a large set of optimization parameters. Like evolution this family of algorithms is able to tackle enormous complex problems with fairly simple means. Here, a simple genetic algorithm [J. H. Holland, Adaptation in Natural and Artificial Systems (Univ. of Michigan, Ann Arbor, 1975)] is used in conjunction with the multiple scattering theory [L. Sánchis et al., Phys. Rev. B 67, 035422 (2003)] to fabricate a new generation of acoustic devices based on a discrete number of cylindrical scatterers. In particular, acoustic lenses [F. Cervera et al., Phys. Rev. Lett. 88, 023902 (2002)] with flat surfaces have been designed to focus the sound in a fixed focal point for one or multiple frequencies. Each scatterer is carefully placed using the optimization method within the preset boundary conditions, to maximize the pressure contribution in the chosen focal spot. With this method acoustic lenses with very low f-numbers of the order 0.3 and with amplifications over 12 dB have been estimated using a reduced number of scatterers (~60). Preliminary results obtained from the experimental realization of the designed devices confirm our predictions.
19. A multivariate joint hydrological drought indicator using vine copula
Liu, Zhiyong; Menzel, Lucas
2016-04-01
We present a multivariate joint hydrological drought indicator using the high-dimensional vine copula. This hydrological indicator is based on the concept of the standardized index (SI) (the version of this algorithm for streamflow is called the standardized streamflow index, simply the SSI). Unlike the single SSI n-month scales (e.g., SSI 1-month or 6-month), this indicator is done without focusing on a certain time window. This means that all different time windows from 1- to 12-months (i.e., the SSI-1 month, SSI 2-month, ..., SSI 12-month) are considered together when developing this hydrological drought indicator. Therefore, in this study, a 12-dimensional joint function is modeled to join the multivariate margins (the distribution functions of the SSI-1 month, SSI 2-month, ..., SSI 12-month) for all time windows based on the copula algorithm. We then used the C-vine copulas to construct the joint dependence of the multivariate margins with window sizes from 1-month to 12-months. To construct the C-vine copula, five bivariate copulas (i.e., Gaussian, Clayton, Frank, Gumbel, and Joe copulas) were considered as the potential pair-copulas (building blocks). Based on well-fitted marginal distributions, a 12-d C-vine copula was used to join the margins, model the joint dependence structure and generate this 12-variate hydrological indicator (named joint streamflow drought indicator, simply JSDI). We tested the performance of this indicator using two hydrological stations in Germany. The results indicate that the JSDI generally combines the strengths of the short-term drought index in capturing the drought onset and medium-term drought index in reflecting the drought duration or persistence. Therefore, it provides a more comprehensive assessment of drought and could be more competitive than other traditional hydrological drought indices (e.g., the SSI). This attractive feature is attributed to the fact that the JSDI describes the overall drought conditions based on
20. (Collection of high quality acoustical records for honeybees)
Kerr, H.T.; Buchanan, M.E.
1987-02-19
High quality acoustical data records were collected for both European and Africanized honeybees under various field conditions. This data base was needed for more rigorous evaluation of a honeybee identification technique previously developed by the travelers from preliminary data sets. Laboratory-grade recording equipment was used to record sounds made by honeybees in and near their nests and during foraging flights. Recordings were obtained from European and Africanized honeybees in the same general environment. Preliminary analyses of the acoustical data base clearly support the general identification algorithm: Africanized honeybee noise has significantly higher frequency content than does European honeybee noise. As this algorithm is refined, it may result in the development of a simple field-portable device for identifying subspecies of honeybees. Further, the honeybee's acoustical signals appear to be correlated with specific colony conditions. Understanding these variations may have enormous benefit for entomologists and for the beekeeping industry. | {"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": 0.6944481134414673, "perplexity": 2500.175932242061}, "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-2017-30/segments/1500549425144.89/warc/CC-MAIN-20170725102459-20170725122459-00296.warc.gz"} |
https://stats.stackexchange.com/questions/250046/how-to-calculate-quartiles-and-other-percentiles | How to calculate quartiles and other percentiles?
Given the following data:
972, 975, 985, 993, 993, 995, 998, 1001, 1004, 1007, 1008, 1009, 1011, 1015, 1016, 1020, 1022, 1032
I calculate the lower quartile as follows:
Number of values: 18, Number of 'gaps': 17.
Lower quartile is at 17/4 + 1 = 5.25th value. 5.25th value is 993 + (995 - 993) x 0.25 = 993.5
Upper quartile is at 3 x 17/4 + 1 = 13.75th value. 13.75th value is 1011 + (1015 - 1011) x 0.75 = 1014
Both the Excel QUARTILE function and the R quantile function agree with me. However the book I am using (Understanding Statistics by Graham Upton and Ian Cook) give different answers (993 and 1015 respectively). I'm confused. Which is correct?
• The correct one is the one that implements the definition in the book. How does this book define a quartile? – whuber Dec 6 '16 at 22:37
As noted by Hyndman and Fan (1996) there are multiple definition of quantiles and different implementations, so it is very likely that you found different estimates calculated from the same data (each of them equally "correct"). I'm afraid that to mention all the differences I'd need to literally reproduce the paper in here, so maybe you should rather read it yourself, as it is available online:
Hyndman, R.J., & Fan, Y. (1996). Sample Quantiles in Statistical Packages. American Statistician, 50(4): 361-365.
Notice that quantile function for R (in fact implemented by Hyndman) enables you to calculate all the nine types of quantiles (using type parameter), check ?quantile to read more. So even R gave you only one of the possible estimates.
As about the estimates, types 1, 2, 3, 5, 6, 8, and 9 return the values reproduced in your book, type 7 (default in quantile function for R) is what you obtained and type 4 disagrees with both estimates.
• Thank you for this resource. I didn't know that there so many. – user140401 Dec 6 '16 at 22:40
• The formula for quantiles given in the book is rn/q + 1/2 where n is the number of observations, r is the rth quantile and q is the number of quantiles. So to calculate the 25th percentile of 10 observations would be 25x10/100 + 1/2 which is the 3rd observation. If I sketch this out on paper it seems reasonable I suppose. However, what I am having trouble with is that this formula gives the 100th percentile as the 10.5th observation. This just doesn't make sense to me. – fractor Dec 7 '16 at 20:51
• @fractor but the authors also mention that interpolation may be needed (as I checked in the Google books copy: books.google.pl/…) – Tim Dec 7 '16 at 22:36
• @Tim So I should extrapolate off the end? This would make the 100th percentile of the data (1, 2) evaluate to 2.5 and the 0th percentile evaluate to 0.5. It is symmetric and seems like something I can get my head around I guess. It just seems odd that the 0th and 100th percentiles may lie outside of the range of the data. – fractor Dec 8 '16 at 12:19
• @fractor I do not own the book and cannot argue for the author or check what did he write (except the Google excerpts). As I said, you can find review in the paper by Hyndman and Fan; there are different approaches to calculating quantiles that employ different solutions for such problems, like rounding or interpolating. I do not think that there is any point with arguing if the approach is "right" or "wrong", simply they used such definition, what you can argue is how consistent is it with the six postulates defined in the paper. – Tim Dec 8 '16 at 13:36 | {"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": 0.7440779805183411, "perplexity": 738.9630362270533}, "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-2020-29/segments/1593655896374.33/warc/CC-MAIN-20200708031342-20200708061342-00282.warc.gz"} |
https://labs.tib.eu/arxiv/?author=A.%20Zabi | • ### Run 2 Upgrades to the CMS Level-1 Calorimeter Trigger(1511.05855)
Nov. 18, 2015 hep-ex, physics.ins-det
The CMS Level-1 calorimeter trigger is being upgraded in two stages to maintain performance as the LHC increases pile-up and instantaneous luminosity in its second run. In the first stage, improved algorithms including event-by-event pile-up corrections are used. New algorithms for heavy ion running have also been developed. In the second stage, higher granularity inputs and a time-multiplexed approach allow for improved position and energy resolution. Data processing in both stages of the upgrade is performed with new, Xilinx Virtex-7 based AMC cards.
• A joint measurement is presented of the branching fractions $B^0_s\to\mu^+\mu^-$ and $B^0\to\mu^+\mu^-$ in proton-proton collisions at the LHC by the CMS and LHCb experiments. The data samples were collected in 2011 at a centre-of-mass energy of 7 TeV, and in 2012 at 8 TeV. The combined analysis produces the first observation of the $B^0_s\to\mu^+\mu^-$ decay, with a statistical significance exceeding six standard deviations, and the best measurement of its branching fraction so far. Furthermore, evidence for the $B^0\to\mu^+\mu^-$ decay is obtained with a statistical significance of three standard deviations. The branching fraction measurements are statistically compatible with SM predictions and impose stringent constraints on several theories beyond the SM.
• ### The D0 Run II Impact Parameter Trigger(physics/0701195)
Jan. 17, 2007 physics.ins-det
Many physics topics to be studied by the D0 experiment during Run II of the Fermilab Tevatron ppbar collider give rise to final states containing b--flavored particles. Examples include Higgs searches, top quark production and decay studies, and full reconstruction of B decays. The sensitivity to such modes has been significantly enhanced by the installation of a silicon based vertex detector as part of the DO detector upgrade for Run II. Interesting events must be identified initially in 100-200 microseconds to be available for later study. This paper describes custom electronics used in the DO trigger system to provide the real--time identification of events having tracks consistent with the decay of b--flavored particles. | {"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": 0.9474121928215027, "perplexity": 2029.5621668647414}, "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/1614178363782.40/warc/CC-MAIN-20210302065019-20210302095019-00240.warc.gz"} |
http://link.springer.com/article/10.1007/BF02747429 | , Volume 10, Issue 1-2, pp 45-51
# Topological defects in crystals: A density-wave theory
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## Abstract
A new approach for describing dislocations and other topological defects in crystals, based on the density wave theory of Ramakrishnan and Yussouff is presented. Quantitative calculations are discussed in brief for the order parameter profiles, the atomic configuration and the free energy of a screw dislocation with Burgers vector $$\overset{\lower0.5em\hbox{\(\smash{\scriptscriptstyle\rightharpoonup}$$}} {b} = (a/2, a/2,a/2 )\) in a bcc solid. Our results for the free energy of the dislocation in a crystal of sizeR, when expressed as (λb 2/4π) ln (αR/|b|) whereλ is the shear elastic constant, yield, for example, the valueα ⋍ 1·85 for sodium at its freezing temperature (371°K). The density distribution in the presence of the dislocation shows that the dislocation core has a columnar character. To our knowledge, this study represents the first calculation of dislocation structure, including the core, within the framework of an order parameter theory incorporating thermal effects. | {"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": 0.6353719234466553, "perplexity": 2327.672299596508}, "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-2014-42/segments/1414119647884.33/warc/CC-MAIN-20141024030047-00193-ip-10-16-133-185.ec2.internal.warc.gz"} |
http://memagazineselect.asmedigitalcollection.asme.org/article.aspx?articleid=2676466 | 0
Select Articles
In a World of Declining Freshwater Availability, We are Exchanging Energy for Clean Water to Meet the Needs of Thirsty Billions.
[+] Author Notes
Michael E. Webber is deputy director of the Energy Institute at the University of Texas at Austin and an ASME Fellow. This article is excerpted from his book, Thirst for Power: Energy, Water and Human Survival, which was published in April 2016 by Yale University Press.
Mechanical Engineering 138(11), 38-43 (Nov 01, 2016) (6 pages) Paper No: ME-16-NOV2; doi: 10.1115/1.2016-Nov-2
## Abstract
This article discusses increasing use of energy water due to increasing unavailability of fresh water. There has been an increasing demand for energy and water even faster than population increase, driven by economic growth on top of the population growth. The increased energy intensity of water has several different components, including stricter water/wastewater treatment standards, deeper aquifer production, long-haul pipelines, and desalination. Each of those elements is more energy intensive than conventional piped water today, and seems to be a more common option moving forward. Rapid desalination growth is also occurring in China, where booming industrial activity is straining water supplies that serve the world’s largest population. While trading energy for water makes a lot of sense in places such as the Middle East or Libya, where there is an abundance of energy and a scarcity of freshwater, that trade-off is not obviously an excellent value in places such as the United Kingdom or the United States, where other cost-effective options such as water conservation, graywater capture, and water reuse might be available.
## Article
The word “tantalize” has its roots in a water-based legend. The Greek gods punished Tantalus, a son of Zeus, by giving him a great thirst and forcing him to stand in a pool of water that always recedes as he leans down to take a drink.
Such a myth feels like a fitting parable for humankind's relationship with abundant water resources that seem to be forever beyond our reach. In fact, it is this inconvenience that drives much of our energy investments for water: we spend significant sums of energy moving, treating, or storing water so that it is available in the form, location, and time we want it. While those energy investments overcome the limits of water's tantalizingly distant location, billions of people still remain without clean, accessible water.
What's more, demand for energy and water has been growing faster than population, driven by economic growth on top of the population growth. Affluent people eat more meat and consume more electricity—two activities that use water. With many water withdrawals coming from nonrenewable resources, the trends for greater consumption will trigger water shortages unless something changes.
Austin's Water Treatment Plant 4, completed in 2014, is capable of treating 50 million gallons a day with room to expand to 300 mgd.
By 2005, at least half of Saudi Arabia's fossil (nonrenewable) water reserves had been consumed in the previous two decades. Significant declines have also been observed in the Ogallala Aquifer under the Great Plains of the United States, spanning eight states from South Dakota to Texas. Water tables in Texas have lowered by as much as 234 feet, while the average drop across the entire aquifer was 14 feet. Storage of water fell from 3.2 billion to 2.9 billion acre-feet.
Overall, water availability is declining globally. Available water dropped from 17,000 cubic meters per person in 1950 to 7,000 cubic meters per person in 2000. Water stress occurs between 1,000 and 1,700 cubic meters, and a water crisis occurs at less than 1,000 cubic meters. Notably, counties such as Qatar, Libya, and Israel are well below 400 cubic meters per person, and even the “green and pleasant” United Kingdom only has 1,222 cubic meters.
All of these datasets point toward a conclusion that water stress is increasing. High-profile research published in Nature has concluded that nearly 80 percent of the global population endures high levels of threat to water security.
This reverse osmosis desalination plant in Barcelona turns the Mediterranean into drinking water.
To compensate for the decline in water availability, we are moving toward more energy-intensive water. This relationship is just one aspect of the energy-water nexus: the dependency of water availability on energy inputs, and the dependency of power generation on available water. The increased energy intensity of water has several different components, including stricter water/wastewater treatment standards, deeper aquifer production, long-haul pipelines, and desalination. Each of those elements is more energy intensive than conventional piped water today, and seems to be a more common option moving forward.
## Cleaner
As societies become wealthier, their concerns shift from focusing on economic growth to protecting the environment. Protecting drinking water quality and preserving the ecosystem from the discharge of water treatment plants are two important pieces of that trend.
But water and wastewater treatment require nontrivial amounts of energy, and advanced treatment methods to meet stricter standards are more energy intensive than treatment for lower standards. For example, advanced treatment systems for wastewater with nitrification require about twice as much energy as trickling filter systems. As we tighten the standards for water and wastewater treatment, we are essentially edging toward increases in energy consumption. While new treatment technologies and methods become more efficient over time after their initial implementation, the standards tighten in parallel. How these balance out is unclear.
At the same time, the water coming into water and wastewater treatment plants is getting more polluted with time. As population grows, there are more discharges into the waterways. Those discharges contain constituents that weren’t always there in such high concentrations. For example, there have been growing concerns about pharmaceuticals (including birth-control pills and pain pills) in sewage streams, which are difficult for wastewater treatment plants to remove. Doing so requires new equipment and ongoing investments of energy.
In an ironic example of the energy-water nexus, some of our energy choices create water quality impacts that require additional energy to treat. For example, increased biofuels production from Midwest corn is expected to cause additional runoff of nitrogen-based fertilizers and other pollution that will require more energy to remove.
Also, the wastewater streams from hydraulic fracturing of shales to produce oil and gas contain much higher levels of total dissolved solids than most wastewater treatment plants can handle. That means more energy has to be spent in one of several ways: on trucking that wastewater to disposal sites or specialized industrial wastewater treatment facilities that might be far away (something that happens rarely), for on-site treatment to recycle and reuse the water in subsequent wells, or on new equipment at the wastewater treatment plant to treat those streams. Even that new equipment is sure to require energy.
## Farther
We are also contemplating moving water farther from its source to the end user. Long-haul pipelines and inter-basin transfer, which is moving water from one river basin to another, are common proposals to solve the crisis of declining local water supplies. While the idea of aqueducts has been around for thousands of years, the scale, length, and volumes of water that are moved are growing.
Some of the classic water transfer systems include the State Water Project in California, which is the state's largest electricity user because it must pump the water over mountains. (It also captures a lot of energy when the water flows back downhill through inline hydroelectric turbines coupled with chutes.) The Hawaiian island of Maui has an incredible series of hand-cut water channels that circle its two volcanoes, moving water miles from the wet portion of the island—one of the wettest places in the United States—to the dry inland plains where farming occurs. This system operates by gravity, and also generates electricity along the way.
Moving forward, as water tables fall and surface sources dry up, municipalities are more likely to consider the cost of expensive and far-flung watergathering systems that pull water to a city from deeper in the ground or farther away. These long-haul systems will generally not be gravity-fed and will require a lot of energy. Plus, they will impact the ecosystem as water from one basin is moved to another, both in terms of loss of water in one watershed and the potential for invasive species in the other.
Perhaps the most ambitious water project in the world is the South-North Transfer Project in China (also known as the South-North Water Diversion Project, or SNWD). The scale, scope, and ambition of the project is reminiscent of U.S. water planners who have dreamed for decades of diverting the Yukon River in Alaska or the Missouri River in the Great Plains to the American Southwest, so that the deserts would bloom with flowers and fruit trees. This project essentially aims to move major southern rivers—the Yangtze and Han—across the country to the Yellow and Hai Rivers. The industrialized north is relatively water poor, whereas the southern part of China is relatively water rich. The total estimated flow for the Chinese endeavor is projected to divert 44.8 billion cubic meters per year from the south more than a thousand miles to the north, at a total cost estimated to be $62 billion. Not to be left out, India is also building its own long-haul water pipeline. And joining the pack, Texas is, too. For example, in Texas, a 240-mile pipeline is being built to bring 370,000 cubic meters per day of water from Lake Palestine to the Dallas-Fort Worth Metroplex. The total capital cost for the construction is estimated to be$888 million, or $3.7 million per mile of pipeline. The annual electricity consumption is expected to be$11.3 million, or $0.71 per cubic meter. In addition, there is a water pipeline that oil and gas tycoon T. Boone Pickens proposed in early 2008 with the expectation that water would be the new oil. The pipeline would move water from Roberts County in the panhandle of Texas toward the Dallas-Fort Worth Metroplex. This project was controversial for a variety of reasons, one of which is that the water rights Pickens holds are for fossil water in the Ogallala aquifer, which can take millions of years to recharge. In Dallas, one of the likely applications for that fossil water would be for sustaining lawns. While some energy would be used for pumping the water out of the aquifer, once it is at the surface, the water would mostly use gravity for its downhill trip to Dallas. Ultimately the deal was scuttled because of the$3 billion price tag for the pipeline. Instead, Pickens sold the water rights to thirsty local cities.
## Fresher
Another of the key trends to watch is how many municipalities are turning to desalination as a solution for water supply issues. In 2013, over 17,000 desalination plants were already installed worldwide, providing approximately 21 billion gallons per day (67 million cubic meters per day) of freshwater. With a blistering pace of growth, that capacity is projected to keep expanding quickly. More than three-fourths of new capacity will be for desalinating seawater, with the rest from brackish groundwater or salty rivers.
While thermal desalination (using heat) represents about 25 percent of the installed capacity by 2010, it represents a shrinking share of new installations as builders seek the less energy intensive reverse osmosis membrane-based system. Even with the lower-energy approach, desalination is still an order of magnitude more energy-intensive than traditional freshwater treatment and distribution. Desalination is capital intensive, too: The annual global desalination market exceeds \$10 billion.
Growth in desalination is particularly rapid in energy-rich, water-poor parts of the world, such as the Middle East, northern Africa, and Australia. After a severe drought that lasted several years, water-strapped Israel famously turned to the sea for its water, rapidly building a handful of desalination plants to produce about 200 billion gallons of freshwater annually by desalting water from the Mediterranean.
The California Aqueduct is a critical part of the State Water Project. The Water Project is the single largest user of electricity in the state.
Photo: California Department of Water Resources
Rapid desalination growth is also occurring in China, where booming industrial activity is straining water supplies that serve the world's largest population. It is also popping up in locations such as London, where a new desalination plant was very controversial and became a big part of several mayoral campaigns.
Despite its relative water wealth, the United States is the world's second-largest market for desalination, trailing only Saudi Arabia. This phenomenon is partly the result of the unequal distribution of water resources across the United States. And, as a wealthy country, the water consumption per capi-ta is quite high and the money to finance large-scale infrastructure projects is available. Projects are un-der consideration for seawater reverse osmosis in coastal states such as California, Texas, and Florida. And projects are under development to serve inland communities that sit atop large brackish aquifers, as in Texas, Arizona, and New Mexico.
The two most energy-intensive options—desalination and long-haul transfer—can also be combined to create an even larger energy requirement for water. Natural water flows occur by gravity, but for seawater desalination, the opposite is true. By definition, coastal waters are at sea level, so moving the water inland requires pumping water uphill. One such desalination project under development in the United States is a coastal facility along the Gulf of Mexico that is designed to provide freshwater for San Antonio, Texas. That means the water would be moved nearly 150 miles inland, increasing in elevation nearly 775 feet.
While trading energy for water makes a lot of sense in places like the Middle East or Libya, where there is an abundance of energy and a scarcity of freshwater, that tradeoff is not obviously a good value in places like the United Kingdom or the United States, where other cost-effective options such as water conservation, graywater capture, and water reuse might be available.
In the end, the most important innovation we need is a new way of thinking about energy and water so that we make better decisions about those precious resources: holistic thinking that recognizes these resources as interconnected, and a systems-level approach that acknowledges how one change in one state to a water system can impact an energy system five states away.
Most important, we need long-range thinking because our energy and water decisions last decades to centuries, so it's imperative that we get them right.
Topics: Water
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https://blogs.princeton.edu/mathclub/guide/courses/algebra/ | Algebra
Algebra is perhaps best defined as the study of “algebraic structures.” Broadly construed, algebraic structures are sets endowed with additional operations—think of the integers (a set) with addition and multiplication (additional operations). Usually, these operations allow elements to be combined in some way, but sometimes they’re better described as allowing transformation of elements into each other as, for instance, in the case of the category of sets endowed with the usual mappings between sets. Such structures are ubiquitous: integers and their various extensions, the vector spaces studied in linear algebra, groups of transformations that encode symmetries, abstract categories that capture relationships between complex objects (like groups themselves) are all examples. Due to this ubiquity, algebra crops up in all areas of mathematics and has a host of applications.
The first two structures you are likely to encounter are groups and rings. In general, groups should be thought of as collections of transformations. That’s because objects in a group can be composed (usually called “multiplication”) and inverted, just like functions, but nothing else is required for a set to have the structure of a group. Groups are important and beautiful objects. For instance, the set of all invertible linear transformations of a vector space to itself is a group, as is the set of all rotations of space (of any number of dimensions). These examples also illustrate the interpretation of groups as symmetries of some other mathematical entity–in this case, a vector space. Groups also play this role in the setting of permutations (symmetries of finite sets), geometric rearrangements of shapes (symmetries of polygons), and Galois theory (symmetries of number systems).
This last example shows how groups can be connected to their more sophisticated cousins, rings. While a ring can be thought of as a group with additional structure, a ring is really a very different animal. Rather than functions and transformations, rings represent numbers. In this case, you can add them, take their negatives, and multiply them—but that’s it. Since many natural number systems lack division (is one divided by two an integer?), it is excluded from the defining properties of rings. When a ring has it anyway, it is called a field–thus, we speak of the “ring of integers,” but the “field of rational (or real, or complex) numbers.” Rings serve as a natural generalization of the integers, and they provide a setting for the study both of abstract objects that resemble them and concrete number systems extending them, like the rational numbers, or the set of all numbers of the form $a + b\sqrt{5}$ with $a, b$ integers.
Now, all of this is just the beginning. We haven’t even mentioned the question of commutativity, or the fact that there is a natural way to think of rings as collections of functions (just ask an algebraic geometer). Nor have we really discussed the rich theory that results in studying the way algebraic objects interact with other mathematical entities. Nor the details of Galois theory. Nor categories. The list goes on and on. But Princeton offers many ways for you to get into these and other algebraic topics. This begins with an introductory sequence that starts with groups, develops the fundamental aspects of the theory behind them, then builds up elementary ring theory and the most important parts of classical Galois theory.
After you’ve completed the introductory sequence, you will be adequately prepared to jump into the more advanced courses that investigate the topics we’ve mentioned above.
In order to graduate with a mathematics degree, it is required to complete at least one algebra course.
Introductory courses
Princeton’s introductory algebra courses cover the three basic algebraic structures: groups, rings, and fields. A group is a structure with one binary operation, such as the set of permutations of {1, 2, …, n}, with the binary operation being composition. A ring is a structure with addition and multiplication, such as the set of polynomials with real coefficients. A field is a ring where each nonzero element has a multiplicative inverse, such as the set of real or complex numbers.
As of Fall 2016, the introductory courses are MAT 345 (mainly groups, rings, and maybe Galois theory or representation theory depending on the teacher) and MAT 346 (sometimes Galois theory; in Spring 2018/19, this has covered local field theory). Neither course has a consistent instructor or text. However, good references for relevant material include the Abstract Algebra text by Dummit and Foote, as well as Algebra by Michael Artin.
MAT 419: Algebraic Number Theory
This course uses a lot of algebra, so you should definitely have taken MAT 345 and MAT 346 first. Knowing Galois theory is especially important. A bit of complex analysis is used towards the end of the course, so having taken MAT 335 beforehand or concurrently would be helpful (there are even a few times where the same proof is done in both classes). There are problem sets approximately every week, which are time consuming but extremely worthwhile. The text for the class is by Samuel, but as it is a very thin book, it can often be helpful to look at other texts, such as Marcus. This course covers quite a lot of material, including some class field theory.
Offered in the Spring.
What to take before? Introductory Sequence.
What to take after? Class Field Theory, Local Fields.
MAT 447: Commutative Algebra
Please check registrar’s page or math department website for information on this course.
What to take before? Introductory Sequence.
What to take after? Introduction to Algebraic Geometry.
MAT 449: Representation Theory
Typically taught by Professor Morel, this course draws on many different areas of mathematics – algebra, geometry and some combinatorics. The first half of the course focuses on studying the linear representations of finite groups — this is a completely worked out theory and the course spent substantial time working out various examples of character tables of finite groups. The second half of the course focused on the representation theory of Lie algebras, in particular on the theory of highest weights. The difference between MAT 455 and this course is that the primary goal in this course is to classify the irreducible representations of the objects in question, while in MAT 455 the emphasis is on their intrinsic geometry — hence, there is value to be derived in taking both courses. The textbook followed is usually Fulton and Harris. In case you are new to working with tensor, symmetric and wedge products, spend some time before the course starts to become familiar with them. Of course, knowledge of basic group theory is essential.
What to take before? Introductory Sequence.
What to take after? You’ll be ready for anything.
Contacts
Max Rabinovich ’13 (mrabinov) for general questions
Ashwath Rabindranath ’13 (arabindr) for algebraic number theory
Sarah Trebat Leder ’13 (strebat) for algebraic number theory
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http://math.stackexchange.com/questions/24465/compute-base-price-of-each-item-in-a-list-of-items-given-the-total-sales-tax | # Compute base price of each item in a list of items given the total sales tax
I'm having a disagreement with a client that I think is relatively simple mathematics, but I'd like a third party to confirm or dispute my assertions. Here's the situation:
We have a list of N final prices p1, ..., pN. A final price is tax-inclusive and includes two kinds of tax:
• flat tax, which is the same for all items
• sales tax, which is a percentage of the item's price
That means that you can define the base price bk of an item to be
pk = (1 + t) · bk + t0
where t0 is the flat tax and t is the sales tax. Alternatively, you can define the price of an item to be
pk = bk + tk
pk = bk + t · bk + t0
bk = pk - tk
where tk is the tax for that item.
Now, the question is:
Given only a list of prices (p1, ..., pN) and the total tax T = t1 + ... + tk, can you determine (b1, ..., bn)? If so, how would you express this?
-
FWIW, my contention is that there aren't a sufficient number of independent equations to solve this without more information (namely the values of either t or t0 or one of the base prices). – John Feminella Mar 1 '11 at 20:19
You are correct, except in the trivial case in which $p_1=p_2=\cdots=p_N$. – Arturo Magidin Mar 1 '11 at 23:19
From the comment, it is clear that you want to figure this out without knowing either the value of $t$ or $t_0$.
With a single price for all items you can: the base price is just the total minus the taxes, divided by the number of items. In fact, you can compute the base price of any item whose final price $p_i$ is exactly $\frac{1}{N}$th the total amount paid, $P=p_1+\cdots+p_N$.
But if you have at least two distinct prices among $p_1,\ldots,p_N$, then you cannot without knowing $t$ or $t_0$, or at least one $b_i$ that does not correspond to a $p_i$ that is exactly $\frac{1}{N}$th of $p_1+\cdots+p_N$. Below is the mathematical development of how to obtain examples, but of course to convince your client that this cannot be done, it will suffice to come up with an example in which the same set of data leads to two different possibilities. If that's all you need, you can skip to the paragraph that begins "So, to construct an example ..."
Corrected.
If the original prices are $(b_1,\ldots,b_N)$, with $B=b_1+\cdots+b_N$, then the total tax on them is $T = tB+Nt_0$. You also know $P=p_1+\cdots+p_N$, so you also know $(1+t)B + Nt_0$. Thus, $P-T = (1+t)B+Nt_0 - (tB+Nt_0) = B$. So we know $B$.
Since $T = tB + Nt_0$ and you know $T$, $B$, and $N$, you can parametrize $t_0$ in terms of $t$: solving for $Nt_0$ we get $Nt_0 = T-tB$.
So each choice of $t$ for which $T-tB\gt 0$ gives a possible choice for $t_0$ that will maintain the same tax.
But you also know $p_i$ for each $i$. Since $$p_i = (1+t)b_i + t_0 = (1+t)b_i + \frac{1}{N}\left(T-tB\right)$$ and since you know $B$, $T$, $N$, and have fixed a value of $t$, you get $$b_i = \frac{1}{1+t}\left(p_i + \frac{1}{N}(tB-T)\right) = \frac{Np_i + tB-T}{N(1+t)}.$$
Each selection of $t$ will give you a value for $b_i$ as above. If you add up the $b_i$ you get $B$; and if you take $(1+t)b_i + t_0$, you will get $$p_i + \frac{1}{N}(tB-T) + t_0 = p_i$$ (since $t_0 = \frac{1}{N}(T-tB)$). Moreover, the tax paid in this case will be \begin{align*} \sum(tb_i) + T-tB &= \sum((1+t)b_i - b_i) + T-tB = \sum(p_i) - \sum b_i + T-tB \\ &= P-B+T-tB = P-(1+t)B+T = T \end{align*} again the right answer.
Will different choices of $t$ yield the same base prices? Not in general. Because if $b_i$ is the value obtained by using $t$ and $b_i'$ is the value obtain by using $t'$, with $t\neq t'$, then setting $b_i=b_i'$ we get \begin{align*} \frac{Np_i+tB-T}{N(1+t)} &=\frac{Np_i+t'B-T}{N(1+t')}\\ (1+t')(Np_i+tB-T) &= (1+t)(Np_i+t'B-T)\\ Np_i + tB - T + t'(Np_i+tB-T) &= Np_i + t'B - T + t(Np_i+t'B-T)\\ (t-t')B + (t'-t)(Np_i - T) &= 0\\ (t-t')(T + B - Np_i) &= 0 \end{align*} which occurs if and only if $Np_i =T+ B = P$, if and only if $Np_i = P$, that is, $p_i$ is exactly $\frac{1}{N}$th the total price. If that is the case, then all possible choices of $t$ will yield the same base price, namely $\frac{1}{N}(P-T)$. But for any $p_i$ which is not exactly $\frac{1}{N}$th of $P$ you will get different values of $b_i$ for each value of $t$.
Therefore, you can get different base prices with different sales tax rates (provided they satisfy $tB\leq T$, with $tB=T$ being the case where the flat tax is $0$).
So, to construct an example, consider the case where the final prices were $10$ and $20$, and the total tax was $3$. So $p_1 = 10$, $p_2 = 20$, $P=30$, $T=3$, $N=2$.
We know that the total base prices were $B = P-T = 27$. This leads to the equation $$2t_0 = 3 - 27t.$$ We want to select two distinct values of $t$ for which $3-27t\gt 0$. That is, $t\lt \frac{1}{9}$. Take $t=.1$.
If $t=.1$, then $2t_0 = 3-2.7 = 0.3$, so $t_0 = 0.15$. We have a 10% sales tax and a 15 cent flat tax. If this is the case, then \begin{align*} b_1 &= \frac{2p_1 + tB-T}{2(1+t)} = \frac{20+.1(27)-3}{2(1.1)} \approx 8.954\\ b_2 &= \frac{2p_2 + tB-t}{2(1+t)} = \frac{40+.1(27)-3}{2(1.1)} \approx 18.045. \end{align*} We can verify that this works: $\$ $8.95 plus a tax of 10% (rounded up) plus 15 cents gives$\10.0. And $\$ $18.05 plus a tax of 10% (rounded down, since we rounded up the price) plus 15 cents gives$\20.00. The total tax paid was $.90 + .15 + 1.80 + .15 = 3.00$.
Now take $t=0.08$. Then $2t_0 = 3-.08(27) = 0.84$, so now we have a sales tax of 6% and a flat tax of 42 cents. In this case, we get \begin{align*} b_1 &= \frac{2p_1 + tB - T}{2(1+t)} = \frac{20 + .08(27)-3}{2(1.08)} \approx 8.87\\ b_2 &= \frac{2p_2 + tB - T}{2(1+t)} = \frac{40 + .08(27) - 3}{2(1.08)} \approx 18.13 \end{align*} A base price of $\$ $8.87, plus an 8% sales tax (71 cents) plus 42 cents flat tax gives$\10.
A base price of $\$ $18.13, plus an 8% sales tax ($\1.45) plus 42 cents flat tax gives $\$ $20. The total tax is$0.71 + 0.42 + 1.45 + 0.42 = 3.00$, again as expected. So we get two possibilities: a 10% sales tax with a 15 cent flat tax, with base prices of$\8.95 and $\$ $18.05; or a sales tax of 8% and a flat tax of 42 cents, with base prices of$\8.87 and $\$ $18.13. Different base prices, same individual final prices, same total tax paid. Knowing a single base price$b_i$which does not correspond to a$p_i$with$Np_i=P$will also suffice, since from the equation $$p_i = (1+t)b_i + \frac{1}{N}\left(T-tB\right)$$ you can solve for$t$, knowing$p_i$,$N$,$T$, and$B$, provided only that$tb_i\neq \frac{B}{N}$, which occurs if and only if$p_i = \frac{P}{N}$. So in summary, without knowing at least one$b_i$that does not correspond to a$p_i$with$Np_i=P$, or knowing$t_0$, or knowing$t$, an at least one price$p_i$not$\frac{1}{N}$th of$P$, you cannot figure out the base prices. But if you know at least one of$t$,$t_0$, or a$b_i$with$Nb_i\neq B=P-T$, then you can (or if all$p_i\$ are equal).
-
Thank you very much for your thorough and complete answer. I was eventually able to get my client to agree that this wasn't possible by constructing a counterexample similar to yours. – John Feminella Mar 2 '11 at 10:18 | {"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": 0.9853324890136719, "perplexity": 398.02710624016726}, "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-2015-48/segments/1448398446997.59/warc/CC-MAIN-20151124205406-00145-ip-10-71-132-137.ec2.internal.warc.gz"} |
http://math.stackexchange.com/questions/226542/connected-rightarrow-path-connected | # connected $\Rightarrow$ path connected?
Well, so far, I have noticed that whenever a matrix lie group is connected it is path connected, so is it true that in matrix lie group connected $\Rightarrow$ path connected?If yes, could anyone tell me where I can get the proof?or if some one tell me the sketch of the proof. Thank you.
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https://www.physicsforums.com/threads/forces-again-review.193730/ | # Forces again (review)
1. Oct 24, 2007
A 25.5 kg block is connected to an empty 1.00 kg bucket by a cord running over a frictionless pulley (Fig. 4-57). The coefficient of static friction between the table and the block is 0.400 and the coefficient of kinetic friction between the table and the block is 0.320. Sand is gradually added to the bucket until the system just begins to move.
I am having the most trouble finding out how to utilize the coefficient of static AND kinetic friction. Do I need to use both? I have my FBDs all drawn up, but I keep on ending up with 2 equations and 3 unknowns.
Take to right as + and down as +...from the FBD of the Block I get $$\sum F=m_Ba$$ implies $$-Fr+T=m_Ba$$ where $$Fr=\mu*N$$ (but I have yet to decide which mu to use?? I would assume since there is an acceleration, I need to use mu of kinetic friction)
$$N_B=m_Bg$$ B=Block. b=bucket
From FBD of bucket I get $$-T+m_bg=m_ba$$
Find the mass of the sand added to the bucket:
Find the acceleration of the system:
A hint would be dope!
Casey
2. Oct 24, 2007
### rocomath
i have a similar problem like this
i was confused on both givens, since your last sentence states that it gradually moves ... use kinetic friction.
3. Oct 24, 2007
Yeah....I keep coming up with too many unknowns...
I get from FBD_B: $$-m_Bg*\mu_k+T=m_Ba$$
so $$T=m_B(a+g\mu)$$ and from FBD_b $$T=m_b(g-a)$$
So I have T, a, and the mass added to the bucket that are unknown...
I was thinking of maybe solving for mu_k AND mu_static......That might provide me with a third equation. Since mu_static-mu_k=0.4-0.32
That might work.....
EDIT: this is an fing mess....any ideas?
Last edited: Oct 24, 2007
4. Oct 24, 2007
I am still jammed on this....do you see what I am missing?
5. Oct 24, 2007
First calculate force of static friction (force required to make the block move):
$$F_{f} = \mu_{s} m g = 0.4(25.5)(9.8) = 99.96 N$$
Now use this to find the mass of sand:
$$F_{f} = F_{w} = m g$$ ==> $$m = F_{f}/g = 99.96/9.8 = 10.2 kg$$
but of course we must subtract the mass of the bucket, so the mass of sand is 10.2kg -1kg = 9.2 kg.
Now to find the acceleration let's first calculate the force of kinetic friction:
$$F_{f} = \mu_{k} m g = 0.32(25.5)(9.8) = 79.968 N$$
Thus the net force on the block once in motion is the force due to the weight of the bucket minus the force of kinetic frictions: F = 99.96 - 79.968 = 19.992 N. Using F = ma (or a = F/m) we have a = 19.992/25.5 = 0.784 m/s^2
Last edited: Oct 24, 2007
6. Oct 24, 2007
Clearly it has been a while since I have used these terms. So N*mu_s is what is required to move the system? and N*mu_k is what is needed to keep it moving. Ah. I vaguely remember a graph in which static friction increases until it maxes out and then it drops to a constant. Thia makes much more sense now.
Thanks,
Casey
7. Oct 24, 2007
yep, you've got it now :)
8. Oct 24, 2007
### rocomath
ah i have learned something tonight, thanks too!
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https://math.stackexchange.com/questions/2069540/what-exactly-is-a-scalar?noredirect=1 | What exactly is a scalar? [closed]
Particularly, referring to scalars I am only implying to individual numbers, for this instance, let's take the set R(real numbers).
These numbers do lie of the real line, i.e. the x axis, which is perpendicular to the y-axis, together form the cartesian plane. So, how are they scalar?
For instance, the number 5 can very well be represented by (5, 0) in the plane, which could also imply that it is a position vector.
If so, let u & v be two vectors in the cartesian plane, then what would the dot product u.v imply? How can the value of it be interpreted? It's obviously not just a random number formed by multiplication of two vectors, what is it that the value of the dot product is so significant?
closed as unclear what you're asking by Servaes, C. Falcon, John B, Henrik, NamasteDec 23 '16 at 14:28
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• In vector analysis, a vector (in the cartesian plane) from origin $O$ [coordinates : $(0,0)$] is defined by a couple of numbers $(a,b)$. A scalar is a number (not a point in the plane). – Mauro ALLEGRANZA Dec 23 '16 at 12:32
• A scalar is an element of the underlying field of a vector space. Elements of the vector space are ordered tuples of elements in the underlying field. The $0$ in $(5,0)$ carries some information. – ÍgjøgnumMeg Dec 23 '16 at 12:32
• See Dot product. – Mauro ALLEGRANZA Dec 23 '16 at 12:32
• @MauroALLEGRANZA, Does a number lie on the real line then? – mathmaniage Dec 23 '16 at 12:41
• Possible duplicate of Why do we use the word "scalar" and not "number" in Linear Algebra? – user378947 Dec 23 '16 at 12:44
There are two parts to this question: What is a scalar?, and Can we represent them as vectors? I think these both stem from the same confusion.
In math, we don't usually think about things by what they are, but rather by how they act. So, if we are thinking about the vector space $\mathbb{R}^{2}$ (over $\mathbb{R}$), it seems like we can identify the set $\{ (x, 0) : x \in \mathbb{R} \}$ with the real numbers. They act somewhat similarly, but they have an essential difference: multiplication.
To get what I mean by that, think about how we define vector spaces. Ignore the dot product for now, since it is not central to vector spaces, but rather something we tack on at a later point (when talking about Inner Product Spaces).
A vector space has two parts to it: the vectors, and the scalars. The vectors are simply things that we can add together, with some rules to make it work nicely. For scalars, the essential operations are multiplication and scaling (we require addition as well, but that is somewhat irrelevant to their purpose). In essence, scalars are built around the idea that we use them to scale vectors, and being able to multiply them is actually a natural consequence of that (for a vector $u$, and scalars $a, b$, it is nice express scaling by both as scaling by their product: $a \cdot (b \cdot u) = (ab) \cdot u$).
More precisely, we can think of scalars by how they act on vectors: given a scalar $a$, we can think about the function $u \mapsto a \cdot u$ (for vectors $u$) which represents scaling by $a$. Again, with this it is tempting to take a particular vector $u$ and identify each scalar $a$ with $a \cdot u$. They work the same additively, but they lose the essential ability to scale (in other words, multiplication). Furthermore, this is not a unique representation, since we could choose any vector $u$. It is interesting, but it is not all that helpful.
Now, this is particularly tempting with $\mathbb{R}^{2}$ because the identification with the $x$-axis seems natural, but one of the central points of linear algebra is that it really is not. Basically, the particular coordinate systems that we choose are not really a meaningful part of the structure, and so it is just as natural to choose any one to represent $\mathbb{R}$.
This is primarily true since we are talking about vector spaces, however. If we were to talk about the complex numbers $\mathbb{C}$, it is a different story. Basically, $\mathbb{C}$ is a vector space over $\mathbb{R}$, and looks exactly like $\mathbb{R}^{2}$, but it has an additional structure: multiplication. Since the complex numbers work like the real numbers (we have addition and multiplication), it is possibly to uniquely represent $\mathbb{R}$ a subset of $\mathbb{C}$. We usually write complex numbers in the form $a + bi$ for real numbers $a, b$, which suggests using $a + 0i$ to represent $a$. In fact, this is precisely the right way to do so to get both addition and multiplication to work right.
Lastly, on the dot product, it really is completely different than it first looks. It is not really multiplication on vectors since the result is a scalar. More precisely, it is not multiplication in the way we have for $\mathbb{R}$ and $\mathbb{C}$ (i.e. for fields). There are all sorts of things we can do in $\mathbb{R}$ (like division) that do not make much sense in $\mathbb{R}^{n}$, even with the dot product.
Really, the most important thing to remember when studying vector spaces (and not more complicated structures like inner product spaces) is that we want everything to be independent of the coordinate system (i.e. basis) that we choose. The dot product is problematic because it makes the standard coordinate system special. Identifying the scalars with a particular axis is problematic because it makes that axis special. Vector addition is good since it is coordinate independent (etc).
• The last sentence has a bit that I think would be logical. My very concept of dot product might be wrong. – mathmaniage Dec 23 '16 at 15:18
There's no such thing as a scalar. But there's a notion of field, and if $k$ is a field, we can speak of the vector spaces over $k$. Sometimes, we've fixed a field $k$, and we're studying vector spaces over it. In this case, we sometimes write "let $a$ denote a scalar" instead of the more formal "let $a$ denote an element of $k$." But that's all it is - a terminological gimmick, no more.
And you're completely correct that $k$ can itself be viewed as a vector space over $k$. This allows us to can say things like "every scalar can be viewed as a vector in a $1$-dimensional vector space" etc.
• how does the value of a dot product's value relate to any one of the vectors? – mathmaniage Dec 23 '16 at 12:52
• @BeshalJaenal, can you be more specific? – goblin Dec 23 '16 at 12:53
• well you see, it's hard to explain. But, taking an instance, the projection formula has (u.v)/(|v|^2), here you see that there is a dot product of u.v, this specific value must represent some specific terminology representing the vector components itself – mathmaniage Dec 23 '16 at 12:55
• I don't know if this would be the perfect analogy but; taking a plank 10" and dividing it by two means that you get 2" planks with 5 quantity. But in the case of dot products, how is a general interpretation possible? We get a number, just a number, which is of significance and it somehow relates to the two vectors in a way, it couldn't be a random number, but how does it do so? – mathmaniage Dec 23 '16 at 12:58
• A 'dot' product, or inner product, is just a function $\cdot :V\times V\to F$, where $V$ is the set of vectors and $F$ if the scalar field. When this function is included in the structure of a vector space, then it is called an inner product space. This allows us to deal with things as length of vectors, angles between them and thus orthogonality. So this is just needed for a lot of geometric concepts to make formal sense. The inner product of two vectors $u,v$ could, informally, be interpreted as, how much of $u$ is 'going' in the same direction as $v$. +(same),0(orthogonal),-(near opposite) – Christopher.L Dec 23 '16 at 13:19
Here's part of the definition of a vector space (taken from here): "A vector space over a field F is a set V together with two operations that satisfy the eight axioms listed below. Elements of V are commonly called vectors. Elements of F are commonly called scalars."
The two operations are usually called vector addition and scalar multiplication. This is also a generalization of, what is known as, a module. When the set of scalars is not 'only' a ring but actually a field, then it is called a vector space.
The scalars are possibly called so because they 'scale' the vectors, but it's of course just a name. For example, when you multiply an 'ordinary' vector, say $(1,2)$ in $\mathbb{R}^2$, with the scalar $3$, you get $(3,6)$, which has the same direction but a greater magnitude.
So in a vector space, you always have a set of objects called vectors and a set of scalars, obeying a list of axioms. The vector spaces are often referred to as a $K$-vector space, where $K$ is the scalar field. We also just say a real vector space about an $\mathbb{R}$-vector space.
Any field, such as the real numbers, could then be considered a vector space over itself. This would then be a set of vectors ($\mathbb{R}$) with a set of scalars ($\mathbb{R}$), where vector addition is the ordinary addition in $\mathbb{R}$ and scalar multiplication is the ordinary multiplication in $\mathbb{R}$. So the real numbers could of course be called scalars in that sense. | {"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": 0.9417818784713745, "perplexity": 221.15978288983106}, "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-2019-22/segments/1558232257939.82/warc/CC-MAIN-20190525084658-20190525110658-00023.warc.gz"} |