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3,131 | Seth Priebatsch recently gave a tedtalk entitled “[Building the game layer on top of the world.](http://www.youtube.com/watch?v=Yn9fTc_WMbo)” In it, Seth described four “game dynamics,” techniques used by game designers to make games fun and addictive. The four dynamics that Priebtsch described were:
1. Appointment dynamic-a dynamic in which to succeed, one must return at a predefined time to take a predetermined action. (Real life example: happy hour)
2. Influence and status-the ability of one player to modify the behavior of another's actions through social pressure. (Example: different color credit cards as a reflection of status)
3. Progression dynamic-a dynamic in which success is granularly displayed and measured through the process of completing itemized tasks. (Example: linkedin profile progress bar)
4. Communal discovery-a dynamic wherein an entire community is rallied to work together to solve a challenge. (Example: finding interesting content on Digg.com)
Seth explained these four game dynamics in his talk and added that his company has an additional three. Does anyone know (or have any theories) about what the other three game dynamics are? | 2010/08/23 | [
"https://gamedev.stackexchange.com/questions/3131",
"https://gamedev.stackexchange.com",
"https://gamedev.stackexchange.com/users/1863/"
] | From [the MDA paper](http://cs.northwestern.edu/~hunicke/MDA.pdf):
>
> 1. Sensation:
> Game as sense-pleasure
> 2. Fantasy:
> Game as make-believe
> 3. Narrative:
> Game as drama
> 4. Challenge:
> Game as obstacle course
> 5. Fellowship:
> Game as social framework
> 6. Discovery:
> Game as uncharted territory
> 7. Expression:
> Game as self-discovery
> 8. Submission:
> Game as pastime
>
>
>
Certainly sounds close, though not quite the same. | I think he actually left out 4 major points (as opposed to 3). These are my guesses based on experience.
**Economies** - Not only do you earn points and level up but you may also spend them at your own will. For instance, look at the bounty system on Stack Exchange sites... I had a burning question to ask that was getting no feedback and had no reputation to spend on it, so I spend 4 days answering a ton of questions so I could post a juicy bounty (and it got me a great answer). There are players in China that play World of Warcraft as a full time job dubbed gold miners because all they do is run around collecting gold in the game to sell online for real money. The same was also true in Diablo II where some of the items were so rare than out of the hundreds of thousands of players playing at any given time over the course of a few years would only find a couple. The rarest item (a Zod rune) of which only one had been found after 3 years of gameplay sold for a reportedly 1100 USD on ebay. If games are the future of social engineering, than Blizzard Entertainment are poised to take over the world because they are the masters. I quit playing World of Warcraft after two weeks because I could tell that the game was more designed to have go on forever, be relatively boring and slow moving, while being designed to be extremely addictive (I had been through a pretty extensive Diablo II phase in the past and learnt that lesson).
**Identity** - Not only is it important to be able to level but it's important to be distinguishable as an individual. Whether that means that you use a alias as your handle or you use your real name. That's what made Facebook win over MySpace. By getting people to use their real names, not only was it easier to find your friends (past or present) online but, by attaching real identities to the handle, most of the trolling/trash talking/spaming/lurking stopped because the people taking part in it could be held accountable. Stack Exchange sites do this by adding the profile to each user's account. World of Warcraft does it by allowing you to customize your character in many ways to look unique. Tiger Woods Golf, as well as Nintendo Wii and XBox360 does it by allowing you to create a custom 3D avatar. Twitter, Stack Exchange, and many other social networks do it by allowing you to respond to a unique user by adding the @ prefix to their name making it easier to have a direct dialog instead of the typical 'talking to a wall' experience of commenting systems that don't use it (IMHO the single greatest simple innovation in social networking ever).
**Scarcity** - Blizzard have mastered this since the days of Diablo I with the 'normal item', 'magical item', 'rare item', 'unique item'. In the early parts of the game, normal items work. As it gets harder magical items become a necessity. Harder still and rare items become a must. Then unique items. Then (in the case of Diablo II on hardest difficulty) they went as far as to make it near impossible to beat without working as a team. As I remember the trade for unique items was a pretty brutal marketplace. It took a lot of work/time/effort on the hardest difficulty to gain worthwhile unique items and it was always a hard bargain to trade for them. World of Warcraft took this a magnitude further by creating the automatic-auction system that mimics ebay to sell items online over the course of a pre-defined time allotment.
**Social Dependence** - In World of Warcraft, It's a lot harder (sometimes impossible) and a lot less fun to play alone. That alone makes it necessary to socialize and group up with other players. In Call of Duty, if you have a decent team all with headsets you gain a huge advantage by being able to share intel on the other team and coordinate attacks. A lot of services sold today offer the 'sign up a friend and save x amount on your first bill' bonuses. Facebook offers the like button and ability to comment on other's posts. Without comments and approval micro-blogging becomes pointless. Ever since the earliest games, the multi-player option has always been a necessity because once you beat a game on single player, there isn't much point in beating it again (IE, the story line is over). Multi-player games enable humans to play together or against each other. In almost every game I've ever played multi-player, with an equal set of advantages/disadvantages the human is always harder to play. About the upper limit of a single player game for playability length is about 60-100 hours of content. Anything beyond that feels tedious. With multi-player, it becomes unlimited (or until the next great multi-player game comes out) because human strategy is dynamic. A top sniper spot on one map one day may become common knowledge in a week thereby making it an easy target. Sometimes, there are anti-strategies where picking a strategically poor position may be a huge advantage because it is unpredictable. The only games where a computer can consistently win are lame algorithmic games with really limited sets of rules and dynamics like chess (IE the computer can calculate every possible move and counter-move before playing out its turn). IMHO, chess is too simplistic to be a chess game. I prefer to place it in the category of mental masturbation. The best part about social dependence is, the game sucks without your friends so you have to get them involved. How much more viral do you get than that. That's how MySpace and Facebook became successful. Nobody wants to have 0 friends online. |
3,131 | Seth Priebatsch recently gave a tedtalk entitled “[Building the game layer on top of the world.](http://www.youtube.com/watch?v=Yn9fTc_WMbo)” In it, Seth described four “game dynamics,” techniques used by game designers to make games fun and addictive. The four dynamics that Priebtsch described were:
1. Appointment dynamic-a dynamic in which to succeed, one must return at a predefined time to take a predetermined action. (Real life example: happy hour)
2. Influence and status-the ability of one player to modify the behavior of another's actions through social pressure. (Example: different color credit cards as a reflection of status)
3. Progression dynamic-a dynamic in which success is granularly displayed and measured through the process of completing itemized tasks. (Example: linkedin profile progress bar)
4. Communal discovery-a dynamic wherein an entire community is rallied to work together to solve a challenge. (Example: finding interesting content on Digg.com)
Seth explained these four game dynamics in his talk and added that his company has an additional three. Does anyone know (or have any theories) about what the other three game dynamics are? | 2010/08/23 | [
"https://gamedev.stackexchange.com/questions/3131",
"https://gamedev.stackexchange.com",
"https://gamedev.stackexchange.com/users/1863/"
] | What he said in his speech is "...with seven game dynamics you can get anyone to do anything..." there was the implication that there were *only* four more.
Then I did some digging and found: <http://techcrunch.com/2010/08/25/scvngr-game-mechanics/>
If the site I accessed is at all correct, there are not four more game dynamics - there are **forty four** more (for a total of 47). >phew<
Instead of listing them all here - just visit the link. :) | <http://www.youtube.com/watch?v=Yn9fTc_WMbo#t=4m09s>
>
> Back at scavenger we like to joke that with seven game dynamics you can get anyone to do anything, so today I'm going to show you four because **I hope to have a competitive advantage at the end of this still.**
>
>
>
You certainly won't get the other three out of him. :)
---
None of those four discusses **creating a history of experiences**. I think this would be a good one; take [Minecraft](http://www.minecraft.net/), for example. A whole community has arisen out of Minecraft because it is so open-ended that people build things and remember those fun experiences long after their physical (virtual) manifestations have been destroyed or deleted. They continue to have fond memories, and hopefully continue to return to the game. The same can be said of many games; it's not only how you are currently playing the game but how you have played it in the past that gives you a good feeling of fun and excitement even after hundreds or thousands of hours of play time. And very few games have that.
---
I think we should ask Jeff Atwood and Joel Spolsky for their insight on this. After all, Stack Exchange is a perfect formula of these different "game dynamics" as evidenced by all the programmers now addicted to the sites. |
42,128 | In a week I'll be traveling from Europe to Santiago de Chile via Atlanta-Hartsfield (ATL). Does anyone have experience with the Automated Passport Control (APC) kiosks at ATL?
I have a relatively short layover and I'm wondering if it is quicker to use the kiosks than filling out the paper form and standing in line? | 2015/01/17 | [
"https://travel.stackexchange.com/questions/42128",
"https://travel.stackexchange.com",
"https://travel.stackexchange.com/users/26145/"
] | The longest part of going through passport control, especially in a busy airport like ATL, is queuing. So eyeball the queue and how fast it's moving.
APC requires you to spend a minute or so at a machine which will print a piece of paper, then show that piece of paper to an officer, so you'll queue twice; but the queues may well be significantly shorter. Each officer handles many more people per hour in the APC lane than in the general foreigner lane, mostly because the general foreigner lane also has people with complex visas. It's possible (but not guaranteed of course) that the officer in the APC lane will ask fewer questions. On the other hand there are probably far fewer officers assigned to the APC lane. So while APC is likely to be faster, the only general answer is that it depends.
Note that you're [eligible for APC](http://www.cbp.gov/travel/us-citizens/automated-passport-control-apc) only if you're a US or Canadian citizen, or you have a visa waiver with an ESTA. If you have an ESTA then you must have visited the US at least once since 2008 (I think that's when they started the current program of taking all fingerprints), otherwise you need to go through the manual lane. | First, the use of the APC kiosk does not mean you will not see the CBP officer, you will still have to see an officer at a booth, it just saves the time by making the job easier for you and for the officer, basically by making you help the officer in doing some of the job (scanning the passport, taking the photograph, etc.).
Hence, the above made the waiting times shorter since the CBP officers can process more application in less time. From the [Atlanta-Hartsfield airport website](http://www.atlanta-airport.com/fifth/newsroom/Press_Release_Article.aspx?id=941):
>
> APC is a self-service kiosk that allows passengers to submit their declaration and biographic information electronically and reduce the time they spend with a CBP officer. This has resulted in an average 20-40% decrease in wait times at airports that use APC kiosks.
>
>
>
So, to answer your question, using the APC kiosk will make the whole process easier and shorter, for you and for everyone else. |
42,128 | In a week I'll be traveling from Europe to Santiago de Chile via Atlanta-Hartsfield (ATL). Does anyone have experience with the Automated Passport Control (APC) kiosks at ATL?
I have a relatively short layover and I'm wondering if it is quicker to use the kiosks than filling out the paper form and standing in line? | 2015/01/17 | [
"https://travel.stackexchange.com/questions/42128",
"https://travel.stackexchange.com",
"https://travel.stackexchange.com/users/26145/"
] | First, the use of the APC kiosk does not mean you will not see the CBP officer, you will still have to see an officer at a booth, it just saves the time by making the job easier for you and for the officer, basically by making you help the officer in doing some of the job (scanning the passport, taking the photograph, etc.).
Hence, the above made the waiting times shorter since the CBP officers can process more application in less time. From the [Atlanta-Hartsfield airport website](http://www.atlanta-airport.com/fifth/newsroom/Press_Release_Article.aspx?id=941):
>
> APC is a self-service kiosk that allows passengers to submit their declaration and biographic information electronically and reduce the time they spend with a CBP officer. This has resulted in an average 20-40% decrease in wait times at airports that use APC kiosks.
>
>
>
So, to answer your question, using the APC kiosk will make the whole process easier and shorter, for you and for everyone else. | APC is pointless in my opinion. I was in transit through Fort Worth airport 2 days ago and had to queue for ages for an APC kiosk (only half were working) then I had to queue for ages again for a rude CPB officer who took my photo and fingerprints again!
APC seems pointless. |
42,128 | In a week I'll be traveling from Europe to Santiago de Chile via Atlanta-Hartsfield (ATL). Does anyone have experience with the Automated Passport Control (APC) kiosks at ATL?
I have a relatively short layover and I'm wondering if it is quicker to use the kiosks than filling out the paper form and standing in line? | 2015/01/17 | [
"https://travel.stackexchange.com/questions/42128",
"https://travel.stackexchange.com",
"https://travel.stackexchange.com/users/26145/"
] | The longest part of going through passport control, especially in a busy airport like ATL, is queuing. So eyeball the queue and how fast it's moving.
APC requires you to spend a minute or so at a machine which will print a piece of paper, then show that piece of paper to an officer, so you'll queue twice; but the queues may well be significantly shorter. Each officer handles many more people per hour in the APC lane than in the general foreigner lane, mostly because the general foreigner lane also has people with complex visas. It's possible (but not guaranteed of course) that the officer in the APC lane will ask fewer questions. On the other hand there are probably far fewer officers assigned to the APC lane. So while APC is likely to be faster, the only general answer is that it depends.
Note that you're [eligible for APC](http://www.cbp.gov/travel/us-citizens/automated-passport-control-apc) only if you're a US or Canadian citizen, or you have a visa waiver with an ESTA. If you have an ESTA then you must have visited the US at least once since 2008 (I think that's when they started the current program of taking all fingerprints), otherwise you need to go through the manual lane. | APC is pointless in my opinion. I was in transit through Fort Worth airport 2 days ago and had to queue for ages for an APC kiosk (only half were working) then I had to queue for ages again for a rude CPB officer who took my photo and fingerprints again!
APC seems pointless. |
58,835 | In *Vampire: The Requiem*, the character has points to spend between attributes, skills, disciplines, etc. Purchasing a new level in a skill, attribute or other merit has a linear cost.
During game however, the xp cost of new level depends on the level of the skill you want to improve, meaning that you **always** should min-max at character creation if you want to optimise the xp-value of your character.
Is there a way to neutralise this effect and ensure xp-equivalence of each character at creation, without needing to calculate too much? | 2015/03/30 | [
"https://rpg.stackexchange.com/questions/58835",
"https://rpg.stackexchange.com",
"https://rpg.stackexchange.com/users/21227/"
] | Yes
---
**Fix:**
Eliminate Bonus points *or* Undo the growing cost increase on attributes, skills, disciplines, etc. *or* Add the growing cost to Bonus Point pricing.
**The Problem**
Baring that, any time where character creation resources have a different math then leveling resources, there will be an 'optimal solution path' in which a character built using that path toward their desired power set will have a mathematical advantage over one that didn't.
In Vampire, it means if we have a guy (Bob) who bought Skills A, B, C, D, & E to four at character creation and a guy (John) who bought A, B, C, & D to five at Chara-gen, and they're both using XP to get rating five in A, B, C, D, & E, then John will have an extra ~15 xp to play with for following the path. | I suppose one must first as, Why must one min-max the character? If your looking at points on a sheet, then I wonder if any Storyteller system will work.
IE: The points on the sheet, should reflect the person. It actually takes more work to go from the Master's to a PhD than it does to go from Bachelor's to Master's, or HSD to Bachelors..
In that I feel the xCurrent Level XP buy is reflexive of natural progression. Also, backed by the rule that you cannot buy from 0 to 4 in a skill with XP. You have to buy them all incrementally.
If I recall, as I don't have my books:
0 > 1 3pts
1+ 2xCurrent level
so ..
1 > 2 2
2 > 3 4
3 > 4 6
etc,
etc..
Now, pregame, what is the character? a Jack of all trades then yes, they should have a lot more points spread out and not min-maxed, a specialist will min-max. The backstory calls for it.
One modification that has proved successful in doing what I think you want, is to not only require the roleplay of working to improve a skill, but to add for a few players a 1 XP skill roleplay at the end of a session. The idea being that a player purposefully chooses and wants to increase a skill or such, goes out of their way to use or or in fact practice.. That should be rewarded. |
90,038 | Does anyone know if an enemy discovering the body of one of his sleeping comrades counts against you for a "Ghost" run? i.e. Not if they get any bolts in the 'detected' meter over their head, but if they just see the fellow thug/guard/etc and say something like "Hey! Wake up!". I was just wondering since it seems to show this stat on the summary screen after a mission and I thought this might mean it's important. | 2012/10/24 | [
"https://gaming.stackexchange.com/questions/90038",
"https://gaming.stackexchange.com",
"https://gaming.stackexchange.com/users/25940/"
] | It doesn't. Here is proof from my recent stealthy, super-lethal playthrough of '[House of Pleasure](http://dishonored.wikia.com/wiki/House_of_Pleasure)' mission stats (With no [Shadow Kill](http://dishonored.wikia.com/wiki/Shadow_Kill). Notice that there are 12 bodies found, but 'Ghost' is checked):
[](https://i.stack.imgur.com/JR3Go.jpg)
Basically, as long as [no red 'marker' appears on an NPC or a wolfhound (dog), it won't count as detected. Three white 'markers' won't count as detected.](https://gaming.stackexchange.com/a/90105/4797) The red marker appears only if an NPC or wolfhound has detected you, not a body you killed or made unconscious.
Also, here are some reports from other posts:
>
> Bodies found does not void the achievements Ghost, Clean hands or Shadow. Completed all three achievements yesterday and I have had missions where bodies were found.
>
>
>
[Source (Reddit /r/dishonored)](http://www.reddit.com/r/dishonored/comments/11skn9/does_this_void_the_achievement/c6pfrky)
Other reports: [[1]](http://www.reddit.com/r/dishonored/comments/11arpe/what_counts_as_an_alarm_i_cant_seem_to_get_a/c6ktbi5) [[2]](http://www.reddit.com/r/dishonored/comments/11skn9/does_this_void_the_achievement/c6pko8j) | No, it does not. I was awarded both Shadow/Ghost on my play-through and I ended up with several bodies discovered in the mission statistics for quite a few missions. |
25,074 | I would like to determine as accurately as possible (ideally within an error limit of +/- 0.25% or better, but I guess that's nigh impossible) the efficiency of a converter, using a simple method.
I need to have the instantaneous value of the efficiency, so calorimetric approaches won't do (Plus I don't have the equipment for that).
By 'instantaneous' I mean that since the switch operates at high frequency - in the upper tens of the kHz range - it will not falsify the results to average them over - say 10 cycles if need be, since the load is switched every few seconds or so; so the time resolution required is in the order of 100-1k measures/second.
Measuring the input and output voltages and currents would be another option, but this gives highly inaccurate results. (Partially because the instrument I use has a limit of 20 A and the current I measure is around a few 100 mA.)
What I have is: a very low power converter (P\_rated = 5 W) with several load points in which to measure the efficiency at constant voltage V\_out = 5 V. I have multimeters and digital scopes (with current probes). Theoretically I can measure on the PCB (I have access to the components and traces.)
Can anybody suggest a setting/method on how I could get some improvement in my measurement accuracy? Or maybe do I need to buy something else to get a better result?
**EDIT**: The converter is a simple buck (DC/DC) converter with a synchronous rectifier *or* a diode (both configurations possible). You can see the full specs [here](http://ww1.microchip.com/downloads/en/DeviceDoc/70181A.pdf).
 | 2012/01/14 | [
"https://electronics.stackexchange.com/questions/25074",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/6007/"
] | Here's a relatively simple solution, but not necessarily a cheap one (depending on your budget).
An oscilloscope is not likely to give you the accuracy you asked for because they typically use an 8-bit ADC, giving 0.2% in measurement uncertainty just from the sampling digitization.
Instead, consider simply using two benchtop multimeters, like Agilent 34401A's. I haven't looked at other models, but the 34401A can measure current at the accuracy you need (for example, 0.05% of reading + 0.005% of full-scale on the 100 mA range).
They can be triggered externally at 300 readings / second (for 5-1/2 digit resolution), so that gets you a sample window much shorter than your load switching cycle. If you hook the meters up to measure the input and output current, then trigger them simultaneously you'll be able to compare the results to determine the efficiency (assuming the input and output voltages are holding constant).
If the input and output voltages are also changing, you may need 4 multimeters to get all the information you need.
If you can synchronize your measurement to the moments when the load switches, you only need half as many multimeters, because you can first measure how the input current & voltage change in response to the load switch and then move the meters around and measure how the output responds to the switching event. | It would seem that the easy part is to measure the wattage being consumed by the load on the 5V output since you can easily use carbon resistors to construct a purely resistive load.
To measure the power consumed by the PS it would seem you would need to do power factor calculations. If accuracy were not so critical something like a [kill-a-watt](http://en.wikipedia.org/wiki/Kill_A_Watt) might be appropriate.
Generally to achieve high accuracy a professional lab would have instruments that were professionally calibrated and certified on a regular basis. An error limit of +/- 0.25% is an extremely tight tolerance since that is a cumulative error across all measurement devices. In other words if the error in measuring input power were 0.1% and the error in measuring output power were 0.2% then the potential total error is 0.3% and already fails to meet your target. Don't forget to take into account the fact that most digital readouts are +- 1 digit which needs to be accounted for as well.
I wish you luck and am anxious to see how you do it. |
25,074 | I would like to determine as accurately as possible (ideally within an error limit of +/- 0.25% or better, but I guess that's nigh impossible) the efficiency of a converter, using a simple method.
I need to have the instantaneous value of the efficiency, so calorimetric approaches won't do (Plus I don't have the equipment for that).
By 'instantaneous' I mean that since the switch operates at high frequency - in the upper tens of the kHz range - it will not falsify the results to average them over - say 10 cycles if need be, since the load is switched every few seconds or so; so the time resolution required is in the order of 100-1k measures/second.
Measuring the input and output voltages and currents would be another option, but this gives highly inaccurate results. (Partially because the instrument I use has a limit of 20 A and the current I measure is around a few 100 mA.)
What I have is: a very low power converter (P\_rated = 5 W) with several load points in which to measure the efficiency at constant voltage V\_out = 5 V. I have multimeters and digital scopes (with current probes). Theoretically I can measure on the PCB (I have access to the components and traces.)
Can anybody suggest a setting/method on how I could get some improvement in my measurement accuracy? Or maybe do I need to buy something else to get a better result?
**EDIT**: The converter is a simple buck (DC/DC) converter with a synchronous rectifier *or* a diode (both configurations possible). You can see the full specs [here](http://ww1.microchip.com/downloads/en/DeviceDoc/70181A.pdf).
 | 2012/01/14 | [
"https://electronics.stackexchange.com/questions/25074",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/6007/"
] | A lot of the following is (hopefully) "applied common sense 101". There is a fair bit of empirical twiddling suggested (a bigger capacitor here causes ... / a longer tome constant helps xxx but makes yyy harder ...). While this may seem to be far more complex that "just using a bench power supply" the same considerations apply whatever is used. If the power supply was created by ascended-masters such as HP or Tektronix it may already be able to deal with fed back noise and rapid current variations. If it was created by lesser-mortals as are many of the cheaper bench power supplies, it may be susceptible to load induced issues without this being apparent. I have seen the voltage **indicated** on two meter (current and voltage)supplies increase very substantially as loading was varied even though the supply was never in current limiting and voltage should have been constant and in fact more or less constant. Adding noise filtering between supply and load tends to fix such problems at the potential cost of adding "burden" resistance. This may be able to be overcome. See below.
The term "burden voltage" is often used to refer to the voltage drop across an ammeter. In tyhe examples below there is ZERO burden resistance.
---
**Simple method:** Input power can be measured adequately well by ensuring that the operating voltage is what is desired and then measuring the current in a manner that produces zero "burden voltage". Below are a simple and an even simpler way to achieve this.
The first diagram will require a few bits and pieces to finish it off (mainly a few capacitors) but is close to usable as is.
R1C1 and R2C2 are simply noise filters for the meters used. The requirements are discussed below.
**Magic. Of sorts.** R\_Isense is used as a current sense resistor. Because the current is sensed before the voltage regulator of IC1/Q1 the voltage drop across it is unimportant. As long as Vin is adequate the drop across R\_Isense may be 0.1 ohm or 1 ohm or 10 ohms or more. There is zero "burden voltage" - the voltage drop across the sense resistor is not reflected in a change in output voltage. Burden voltage = zero.
Rather than using a resistor at R\_Isense an ammeter can be used. This also does not affect the output voltage and burden voltage is zero.
If the circuit switches between a sleep and awake mode with currents in the microamps range in the first case and 10's or 100's of mA in the latter I find it useful to use an ammeter set to auto-range io place of R\_Isense OR an autoranging voltmeter across R\_Isense. This allows current in either mode to be displayed and again/still there is zero burden voltage as the meter is on the input side of the voltage regulator formed by IC1/Q1.
Q1 and IC1 are a basic voltage regulator. The aim is to hold Vout at the same voltage as Vr. Say +5 VDC or whatever. To keep the very basic operation of the circuit clear I have not shown any noise filtering on Vout or in the opamp feedback loop, as discussed below. Filtering can be as heavy as is needed to get a clean Vout and as minimal as required to maintain response to load steps. A larger capacitor across Vout will make maintaining voltage easier BUT will prevent rapid current variations being seen across Isense. If Vout rises above Vr then op-amp output goes low turning Q1 off and reducing Vout as required. As shown the opamp is a comparator with open loop action and no feedback. While this would work OK, the user may wish to give the opamp finite gain by using negative feedback. An N Channel MOSFET is sused but this could be a P Channel MOSFEt with inverted drive to the opamp. Q1 could be bipolar but there is no obvious advantage in not using a MOSFET in typical cases.
As shown the noise from the buck regulator may (will) disrupt the opamp feedback loop. A capacitor can be added across Vout to source current peaks and rapid variations and reduce smps noise. A filter as per R1C1 nd R2C2 can be added between Vout and inverting input to reduce noise that may affect the opamp. An RC filter to the inverting input with a 1/time-constant several decades below the smps switchiong frequency should suffice. eg if the buck regulator operates at 100 kHz then a filter frequency of <= 1 kHz is a good starting point. eh 10k, 0.1 uF.
time constant t = RC = 10,000 x 1E-7 = 0.001 or Frc =~~~ 1 kHz.
Once you get Voltage supply "stable enough" as load varies you get some free magic. Supply current flows through R\_Isense. Load current can be determined by measuring voltage across here. Thje more voltage you allow to drop across R\_Isense the more accuracy (actually resolution) is available for determining current. If say I\_load max = 100 mA. If R\_Isense is 10 ohms it will drop 1 volt at 100 mA. If R\_Isense = 100 ohms it will drop 10 Volt at 100 mA. Obviously Vin has to bve large enough to allow this. A 4 digit voltmeter will allow you to resolve 0.1 mA steps at 100 mA full scale. If available a 6 digit voltmeter of whatever accuracy it happens to be will allow you to resolve 1 uA steps. A meter with 6 digit "accuracy" is unlikely to be available. The use of a multi ranging meter, as mentioned above, effectively gives high accuracy and resolution.
---
**SIMPLER:**
An annoying to use but simpler and super low cost solution is as per the diagram below.
This is functionally equivalent to the prior arrangement but uses no active electronics and again has zero effective burden voltage.
Current is sensed with R\_Isense or an ammeter at this position and Vout is then measured with the meter at Vout2. Filtering is often crucial for correct meter operation. As voltmeters are used R1C1 and R2 C2 time constants can be as high as required to remove smps noise at the expense of loss of response time.
---
Load power measurement is "more of the same."
Voltage measurement with filtered meter to reduce smps noise enough. "Enough" will vary with manufacturer and noise level but is "easy", as above
If Rload is constant Power out can be inferred.
If Rload is dynamic then a current sense resistor or equivalent is needed. Again - "adequate" filtering is essential - with "adequate depending on immunity of meter to smps noise.
 | It would seem that the easy part is to measure the wattage being consumed by the load on the 5V output since you can easily use carbon resistors to construct a purely resistive load.
To measure the power consumed by the PS it would seem you would need to do power factor calculations. If accuracy were not so critical something like a [kill-a-watt](http://en.wikipedia.org/wiki/Kill_A_Watt) might be appropriate.
Generally to achieve high accuracy a professional lab would have instruments that were professionally calibrated and certified on a regular basis. An error limit of +/- 0.25% is an extremely tight tolerance since that is a cumulative error across all measurement devices. In other words if the error in measuring input power were 0.1% and the error in measuring output power were 0.2% then the potential total error is 0.3% and already fails to meet your target. Don't forget to take into account the fact that most digital readouts are +- 1 digit which needs to be accounted for as well.
I wish you luck and am anxious to see how you do it. |
25,074 | I would like to determine as accurately as possible (ideally within an error limit of +/- 0.25% or better, but I guess that's nigh impossible) the efficiency of a converter, using a simple method.
I need to have the instantaneous value of the efficiency, so calorimetric approaches won't do (Plus I don't have the equipment for that).
By 'instantaneous' I mean that since the switch operates at high frequency - in the upper tens of the kHz range - it will not falsify the results to average them over - say 10 cycles if need be, since the load is switched every few seconds or so; so the time resolution required is in the order of 100-1k measures/second.
Measuring the input and output voltages and currents would be another option, but this gives highly inaccurate results. (Partially because the instrument I use has a limit of 20 A and the current I measure is around a few 100 mA.)
What I have is: a very low power converter (P\_rated = 5 W) with several load points in which to measure the efficiency at constant voltage V\_out = 5 V. I have multimeters and digital scopes (with current probes). Theoretically I can measure on the PCB (I have access to the components and traces.)
Can anybody suggest a setting/method on how I could get some improvement in my measurement accuracy? Or maybe do I need to buy something else to get a better result?
**EDIT**: The converter is a simple buck (DC/DC) converter with a synchronous rectifier *or* a diode (both configurations possible). You can see the full specs [here](http://ww1.microchip.com/downloads/en/DeviceDoc/70181A.pdf).
 | 2012/01/14 | [
"https://electronics.stackexchange.com/questions/25074",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/6007/"
] | Here's a relatively simple solution, but not necessarily a cheap one (depending on your budget).
An oscilloscope is not likely to give you the accuracy you asked for because they typically use an 8-bit ADC, giving 0.2% in measurement uncertainty just from the sampling digitization.
Instead, consider simply using two benchtop multimeters, like Agilent 34401A's. I haven't looked at other models, but the 34401A can measure current at the accuracy you need (for example, 0.05% of reading + 0.005% of full-scale on the 100 mA range).
They can be triggered externally at 300 readings / second (for 5-1/2 digit resolution), so that gets you a sample window much shorter than your load switching cycle. If you hook the meters up to measure the input and output current, then trigger them simultaneously you'll be able to compare the results to determine the efficiency (assuming the input and output voltages are holding constant).
If the input and output voltages are also changing, you may need 4 multimeters to get all the information you need.
If you can synchronize your measurement to the moments when the load switches, you only need half as many multimeters, because you can first measure how the input current & voltage change in response to the load switch and then move the meters around and measure how the output responds to the switching event. | I assume that the input is a DC source (I try guessing: a photovoltaic panel?).
OPTION1: A I->V converter at the output of the converter, like the MAX4173 that you have on the board, and the same at the input. Then, using the oscilloscope with a good averaging, you can measure quite accurately the power consumed using 2 channels for the input (V-I) and 2 for the output. Other than simply measuring the values, you can use the mathematical functions of the scope or (the best in my opinion) use the USB interface of the scope with the drivers provided by Agilent (I'm using these driver for the N6705B but they must exist also for your scope) and download data to your PC.
OPTION2 (simpler but less accurate): you can directly measure the output current with the signal feed to the ADC of the dsPIC: you have to consider also the power consumed by the voltage divider, but it's an easy task if you know the exact value of the resistors (possible) and the output voltage (that you have). For the input you still need a V->I converter, but it's quite easily doable with something like [this](http://www.diodes.com/datasheets/ZXCT1009.pdf).
Maybe the scope doesn't have the highest precision, but with many samples you can still get better results and it gives you a flexibility that the handheld multimeter doesn't have. And interfacing it with a PC you get access to the widest range of analysis.
OPTION3: If the source gives a slowly changing voltage, you can just use the multimeter to measure current and voltage; the problem is that this way you can't save the data automatically.
NOTE: Since probably the output voltage has an AC component due to the switching, you could try to average over a finite number of periods of the ripple. |
25,074 | I would like to determine as accurately as possible (ideally within an error limit of +/- 0.25% or better, but I guess that's nigh impossible) the efficiency of a converter, using a simple method.
I need to have the instantaneous value of the efficiency, so calorimetric approaches won't do (Plus I don't have the equipment for that).
By 'instantaneous' I mean that since the switch operates at high frequency - in the upper tens of the kHz range - it will not falsify the results to average them over - say 10 cycles if need be, since the load is switched every few seconds or so; so the time resolution required is in the order of 100-1k measures/second.
Measuring the input and output voltages and currents would be another option, but this gives highly inaccurate results. (Partially because the instrument I use has a limit of 20 A and the current I measure is around a few 100 mA.)
What I have is: a very low power converter (P\_rated = 5 W) with several load points in which to measure the efficiency at constant voltage V\_out = 5 V. I have multimeters and digital scopes (with current probes). Theoretically I can measure on the PCB (I have access to the components and traces.)
Can anybody suggest a setting/method on how I could get some improvement in my measurement accuracy? Or maybe do I need to buy something else to get a better result?
**EDIT**: The converter is a simple buck (DC/DC) converter with a synchronous rectifier *or* a diode (both configurations possible). You can see the full specs [here](http://ww1.microchip.com/downloads/en/DeviceDoc/70181A.pdf).
 | 2012/01/14 | [
"https://electronics.stackexchange.com/questions/25074",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/6007/"
] | Here's a relatively simple solution, but not necessarily a cheap one (depending on your budget).
An oscilloscope is not likely to give you the accuracy you asked for because they typically use an 8-bit ADC, giving 0.2% in measurement uncertainty just from the sampling digitization.
Instead, consider simply using two benchtop multimeters, like Agilent 34401A's. I haven't looked at other models, but the 34401A can measure current at the accuracy you need (for example, 0.05% of reading + 0.005% of full-scale on the 100 mA range).
They can be triggered externally at 300 readings / second (for 5-1/2 digit resolution), so that gets you a sample window much shorter than your load switching cycle. If you hook the meters up to measure the input and output current, then trigger them simultaneously you'll be able to compare the results to determine the efficiency (assuming the input and output voltages are holding constant).
If the input and output voltages are also changing, you may need 4 multimeters to get all the information you need.
If you can synchronize your measurement to the moments when the load switches, you only need half as many multimeters, because you can first measure how the input current & voltage change in response to the load switch and then move the meters around and measure how the output responds to the switching event. | A lot of the following is (hopefully) "applied common sense 101". There is a fair bit of empirical twiddling suggested (a bigger capacitor here causes ... / a longer tome constant helps xxx but makes yyy harder ...). While this may seem to be far more complex that "just using a bench power supply" the same considerations apply whatever is used. If the power supply was created by ascended-masters such as HP or Tektronix it may already be able to deal with fed back noise and rapid current variations. If it was created by lesser-mortals as are many of the cheaper bench power supplies, it may be susceptible to load induced issues without this being apparent. I have seen the voltage **indicated** on two meter (current and voltage)supplies increase very substantially as loading was varied even though the supply was never in current limiting and voltage should have been constant and in fact more or less constant. Adding noise filtering between supply and load tends to fix such problems at the potential cost of adding "burden" resistance. This may be able to be overcome. See below.
The term "burden voltage" is often used to refer to the voltage drop across an ammeter. In tyhe examples below there is ZERO burden resistance.
---
**Simple method:** Input power can be measured adequately well by ensuring that the operating voltage is what is desired and then measuring the current in a manner that produces zero "burden voltage". Below are a simple and an even simpler way to achieve this.
The first diagram will require a few bits and pieces to finish it off (mainly a few capacitors) but is close to usable as is.
R1C1 and R2C2 are simply noise filters for the meters used. The requirements are discussed below.
**Magic. Of sorts.** R\_Isense is used as a current sense resistor. Because the current is sensed before the voltage regulator of IC1/Q1 the voltage drop across it is unimportant. As long as Vin is adequate the drop across R\_Isense may be 0.1 ohm or 1 ohm or 10 ohms or more. There is zero "burden voltage" - the voltage drop across the sense resistor is not reflected in a change in output voltage. Burden voltage = zero.
Rather than using a resistor at R\_Isense an ammeter can be used. This also does not affect the output voltage and burden voltage is zero.
If the circuit switches between a sleep and awake mode with currents in the microamps range in the first case and 10's or 100's of mA in the latter I find it useful to use an ammeter set to auto-range io place of R\_Isense OR an autoranging voltmeter across R\_Isense. This allows current in either mode to be displayed and again/still there is zero burden voltage as the meter is on the input side of the voltage regulator formed by IC1/Q1.
Q1 and IC1 are a basic voltage regulator. The aim is to hold Vout at the same voltage as Vr. Say +5 VDC or whatever. To keep the very basic operation of the circuit clear I have not shown any noise filtering on Vout or in the opamp feedback loop, as discussed below. Filtering can be as heavy as is needed to get a clean Vout and as minimal as required to maintain response to load steps. A larger capacitor across Vout will make maintaining voltage easier BUT will prevent rapid current variations being seen across Isense. If Vout rises above Vr then op-amp output goes low turning Q1 off and reducing Vout as required. As shown the opamp is a comparator with open loop action and no feedback. While this would work OK, the user may wish to give the opamp finite gain by using negative feedback. An N Channel MOSFET is sused but this could be a P Channel MOSFEt with inverted drive to the opamp. Q1 could be bipolar but there is no obvious advantage in not using a MOSFET in typical cases.
As shown the noise from the buck regulator may (will) disrupt the opamp feedback loop. A capacitor can be added across Vout to source current peaks and rapid variations and reduce smps noise. A filter as per R1C1 nd R2C2 can be added between Vout and inverting input to reduce noise that may affect the opamp. An RC filter to the inverting input with a 1/time-constant several decades below the smps switchiong frequency should suffice. eg if the buck regulator operates at 100 kHz then a filter frequency of <= 1 kHz is a good starting point. eh 10k, 0.1 uF.
time constant t = RC = 10,000 x 1E-7 = 0.001 or Frc =~~~ 1 kHz.
Once you get Voltage supply "stable enough" as load varies you get some free magic. Supply current flows through R\_Isense. Load current can be determined by measuring voltage across here. Thje more voltage you allow to drop across R\_Isense the more accuracy (actually resolution) is available for determining current. If say I\_load max = 100 mA. If R\_Isense is 10 ohms it will drop 1 volt at 100 mA. If R\_Isense = 100 ohms it will drop 10 Volt at 100 mA. Obviously Vin has to bve large enough to allow this. A 4 digit voltmeter will allow you to resolve 0.1 mA steps at 100 mA full scale. If available a 6 digit voltmeter of whatever accuracy it happens to be will allow you to resolve 1 uA steps. A meter with 6 digit "accuracy" is unlikely to be available. The use of a multi ranging meter, as mentioned above, effectively gives high accuracy and resolution.
---
**SIMPLER:**
An annoying to use but simpler and super low cost solution is as per the diagram below.
This is functionally equivalent to the prior arrangement but uses no active electronics and again has zero effective burden voltage.
Current is sensed with R\_Isense or an ammeter at this position and Vout is then measured with the meter at Vout2. Filtering is often crucial for correct meter operation. As voltmeters are used R1C1 and R2 C2 time constants can be as high as required to remove smps noise at the expense of loss of response time.
---
Load power measurement is "more of the same."
Voltage measurement with filtered meter to reduce smps noise enough. "Enough" will vary with manufacturer and noise level but is "easy", as above
If Rload is constant Power out can be inferred.
If Rload is dynamic then a current sense resistor or equivalent is needed. Again - "adequate" filtering is essential - with "adequate depending on immunity of meter to smps noise.
 |
25,074 | I would like to determine as accurately as possible (ideally within an error limit of +/- 0.25% or better, but I guess that's nigh impossible) the efficiency of a converter, using a simple method.
I need to have the instantaneous value of the efficiency, so calorimetric approaches won't do (Plus I don't have the equipment for that).
By 'instantaneous' I mean that since the switch operates at high frequency - in the upper tens of the kHz range - it will not falsify the results to average them over - say 10 cycles if need be, since the load is switched every few seconds or so; so the time resolution required is in the order of 100-1k measures/second.
Measuring the input and output voltages and currents would be another option, but this gives highly inaccurate results. (Partially because the instrument I use has a limit of 20 A and the current I measure is around a few 100 mA.)
What I have is: a very low power converter (P\_rated = 5 W) with several load points in which to measure the efficiency at constant voltage V\_out = 5 V. I have multimeters and digital scopes (with current probes). Theoretically I can measure on the PCB (I have access to the components and traces.)
Can anybody suggest a setting/method on how I could get some improvement in my measurement accuracy? Or maybe do I need to buy something else to get a better result?
**EDIT**: The converter is a simple buck (DC/DC) converter with a synchronous rectifier *or* a diode (both configurations possible). You can see the full specs [here](http://ww1.microchip.com/downloads/en/DeviceDoc/70181A.pdf).
 | 2012/01/14 | [
"https://electronics.stackexchange.com/questions/25074",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/6007/"
] | A lot of the following is (hopefully) "applied common sense 101". There is a fair bit of empirical twiddling suggested (a bigger capacitor here causes ... / a longer tome constant helps xxx but makes yyy harder ...). While this may seem to be far more complex that "just using a bench power supply" the same considerations apply whatever is used. If the power supply was created by ascended-masters such as HP or Tektronix it may already be able to deal with fed back noise and rapid current variations. If it was created by lesser-mortals as are many of the cheaper bench power supplies, it may be susceptible to load induced issues without this being apparent. I have seen the voltage **indicated** on two meter (current and voltage)supplies increase very substantially as loading was varied even though the supply was never in current limiting and voltage should have been constant and in fact more or less constant. Adding noise filtering between supply and load tends to fix such problems at the potential cost of adding "burden" resistance. This may be able to be overcome. See below.
The term "burden voltage" is often used to refer to the voltage drop across an ammeter. In tyhe examples below there is ZERO burden resistance.
---
**Simple method:** Input power can be measured adequately well by ensuring that the operating voltage is what is desired and then measuring the current in a manner that produces zero "burden voltage". Below are a simple and an even simpler way to achieve this.
The first diagram will require a few bits and pieces to finish it off (mainly a few capacitors) but is close to usable as is.
R1C1 and R2C2 are simply noise filters for the meters used. The requirements are discussed below.
**Magic. Of sorts.** R\_Isense is used as a current sense resistor. Because the current is sensed before the voltage regulator of IC1/Q1 the voltage drop across it is unimportant. As long as Vin is adequate the drop across R\_Isense may be 0.1 ohm or 1 ohm or 10 ohms or more. There is zero "burden voltage" - the voltage drop across the sense resistor is not reflected in a change in output voltage. Burden voltage = zero.
Rather than using a resistor at R\_Isense an ammeter can be used. This also does not affect the output voltage and burden voltage is zero.
If the circuit switches between a sleep and awake mode with currents in the microamps range in the first case and 10's or 100's of mA in the latter I find it useful to use an ammeter set to auto-range io place of R\_Isense OR an autoranging voltmeter across R\_Isense. This allows current in either mode to be displayed and again/still there is zero burden voltage as the meter is on the input side of the voltage regulator formed by IC1/Q1.
Q1 and IC1 are a basic voltage regulator. The aim is to hold Vout at the same voltage as Vr. Say +5 VDC or whatever. To keep the very basic operation of the circuit clear I have not shown any noise filtering on Vout or in the opamp feedback loop, as discussed below. Filtering can be as heavy as is needed to get a clean Vout and as minimal as required to maintain response to load steps. A larger capacitor across Vout will make maintaining voltage easier BUT will prevent rapid current variations being seen across Isense. If Vout rises above Vr then op-amp output goes low turning Q1 off and reducing Vout as required. As shown the opamp is a comparator with open loop action and no feedback. While this would work OK, the user may wish to give the opamp finite gain by using negative feedback. An N Channel MOSFET is sused but this could be a P Channel MOSFEt with inverted drive to the opamp. Q1 could be bipolar but there is no obvious advantage in not using a MOSFET in typical cases.
As shown the noise from the buck regulator may (will) disrupt the opamp feedback loop. A capacitor can be added across Vout to source current peaks and rapid variations and reduce smps noise. A filter as per R1C1 nd R2C2 can be added between Vout and inverting input to reduce noise that may affect the opamp. An RC filter to the inverting input with a 1/time-constant several decades below the smps switchiong frequency should suffice. eg if the buck regulator operates at 100 kHz then a filter frequency of <= 1 kHz is a good starting point. eh 10k, 0.1 uF.
time constant t = RC = 10,000 x 1E-7 = 0.001 or Frc =~~~ 1 kHz.
Once you get Voltage supply "stable enough" as load varies you get some free magic. Supply current flows through R\_Isense. Load current can be determined by measuring voltage across here. Thje more voltage you allow to drop across R\_Isense the more accuracy (actually resolution) is available for determining current. If say I\_load max = 100 mA. If R\_Isense is 10 ohms it will drop 1 volt at 100 mA. If R\_Isense = 100 ohms it will drop 10 Volt at 100 mA. Obviously Vin has to bve large enough to allow this. A 4 digit voltmeter will allow you to resolve 0.1 mA steps at 100 mA full scale. If available a 6 digit voltmeter of whatever accuracy it happens to be will allow you to resolve 1 uA steps. A meter with 6 digit "accuracy" is unlikely to be available. The use of a multi ranging meter, as mentioned above, effectively gives high accuracy and resolution.
---
**SIMPLER:**
An annoying to use but simpler and super low cost solution is as per the diagram below.
This is functionally equivalent to the prior arrangement but uses no active electronics and again has zero effective burden voltage.
Current is sensed with R\_Isense or an ammeter at this position and Vout is then measured with the meter at Vout2. Filtering is often crucial for correct meter operation. As voltmeters are used R1C1 and R2 C2 time constants can be as high as required to remove smps noise at the expense of loss of response time.
---
Load power measurement is "more of the same."
Voltage measurement with filtered meter to reduce smps noise enough. "Enough" will vary with manufacturer and noise level but is "easy", as above
If Rload is constant Power out can be inferred.
If Rload is dynamic then a current sense resistor or equivalent is needed. Again - "adequate" filtering is essential - with "adequate depending on immunity of meter to smps noise.
 | I assume that the input is a DC source (I try guessing: a photovoltaic panel?).
OPTION1: A I->V converter at the output of the converter, like the MAX4173 that you have on the board, and the same at the input. Then, using the oscilloscope with a good averaging, you can measure quite accurately the power consumed using 2 channels for the input (V-I) and 2 for the output. Other than simply measuring the values, you can use the mathematical functions of the scope or (the best in my opinion) use the USB interface of the scope with the drivers provided by Agilent (I'm using these driver for the N6705B but they must exist also for your scope) and download data to your PC.
OPTION2 (simpler but less accurate): you can directly measure the output current with the signal feed to the ADC of the dsPIC: you have to consider also the power consumed by the voltage divider, but it's an easy task if you know the exact value of the resistors (possible) and the output voltage (that you have). For the input you still need a V->I converter, but it's quite easily doable with something like [this](http://www.diodes.com/datasheets/ZXCT1009.pdf).
Maybe the scope doesn't have the highest precision, but with many samples you can still get better results and it gives you a flexibility that the handheld multimeter doesn't have. And interfacing it with a PC you get access to the widest range of analysis.
OPTION3: If the source gives a slowly changing voltage, you can just use the multimeter to measure current and voltage; the problem is that this way you can't save the data automatically.
NOTE: Since probably the output voltage has an AC component due to the switching, you could try to average over a finite number of periods of the ripple. |
666,381 | I need to write an application that accepts very simple doodles by users, kind of like in [tenthousandcents](http://www.tenthousandcents.com/) and [thesheepmarket](http://www.thesheepmarket.com/).
For example, I might want users to write their name using their mouse.
Any suggestions?
I don't even need to host it myself. If there are services offered somewhere that I can just use that is fine. | 2009/03/20 | [
"https://Stackoverflow.com/questions/666381",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/20498/"
] | Another flash alternative and I just happen to like SVG.
[Amaltas SVG Web App](http://www.amaltas.org/svgapp/) | Well, tenthousandcents is a Adobe Flash application. The best place to start is to begin learning Flash if you'd really like to make something similar. There's really not going to be anything easy about accepting even simple doodles if you don't know any frameworks. |
666,381 | I need to write an application that accepts very simple doodles by users, kind of like in [tenthousandcents](http://www.tenthousandcents.com/) and [thesheepmarket](http://www.thesheepmarket.com/).
For example, I might want users to write their name using their mouse.
Any suggestions?
I don't even need to host it myself. If there are services offered somewhere that I can just use that is fine. | 2009/03/20 | [
"https://Stackoverflow.com/questions/666381",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/20498/"
] | Another flash alternative and I just happen to like SVG.
[Amaltas SVG Web App](http://www.amaltas.org/svgapp/) | You could use a java applet like [Shi-painter](http://hp.vector.co.jp/authors/VA016309/spainter/index_en.html) like many [oekaki](http://en.wikipedia.org/wiki/Oekaki) implementations do, such as [the one at iiichan.net](http://iiichan.net/boards/oekaki/paint.pl?oek_painter=shi_norm&oek_x=300&oek_y=300).
Disclaimer: I understand the stigma associated with java applets these days, but I thought I'd include this for the sake of completeness. ;) |
666,381 | I need to write an application that accepts very simple doodles by users, kind of like in [tenthousandcents](http://www.tenthousandcents.com/) and [thesheepmarket](http://www.thesheepmarket.com/).
For example, I might want users to write their name using their mouse.
Any suggestions?
I don't even need to host it myself. If there are services offered somewhere that I can just use that is fine. | 2009/03/20 | [
"https://Stackoverflow.com/questions/666381",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/20498/"
] | So far, the best and easiest solution I have found is to use something like this:
<http://www.flashnifties.com/flash_guestbook.php> | Another flash alternative and I just happen to like SVG.
[Amaltas SVG Web App](http://www.amaltas.org/svgapp/) |
666,381 | I need to write an application that accepts very simple doodles by users, kind of like in [tenthousandcents](http://www.tenthousandcents.com/) and [thesheepmarket](http://www.thesheepmarket.com/).
For example, I might want users to write their name using their mouse.
Any suggestions?
I don't even need to host it myself. If there are services offered somewhere that I can just use that is fine. | 2009/03/20 | [
"https://Stackoverflow.com/questions/666381",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/20498/"
] | So far, the best and easiest solution I have found is to use something like this:
<http://www.flashnifties.com/flash_guestbook.php> | One option is to use the HTML5 `<canvas>` tag, supported in Firefox, Safari, and Opera, with javascript, then uploading the image in form data.
This blocks out everyone using IE, though.
Adobe Flash is probably your best option. |
30,546 | I got a big self watering pot with 3 different plants. After some weeks it got some mold (something like [this](https://gardening.stackexchange.com/questions/1562/my-indoor-plant-has-an-orange-mold-like-substance-growing-on-it-and-has-tiny-whi), but I got it earlier) in it and after trying some stuff in the internet I ended up changing the soil to stop the mold from growing.
In this pot there is a fern, a fittonia and succulent and I'm starting to think the fern is getting too much water.
I also got 3 other self-watering pots. One of them has an oregano, another has a small pepper and the last one has a cherry tomato. The oregano has some leaves with brown tips (I learned [here](https://www.youtube.com/watch?v=9gxnQNJopqg) that it might be overwatering), the pepper is not very good as well ([some pictures here](https://gardening.stackexchange.com/questions/30543/should-i-cut-off-the-withered-parts-of-my-pepper)), and the cherry tomato is not the best either.
I keep all those plants indoors, there is no direct sunlight but there is clarity.
Are those pots viable for this situation? I feel that my plants are getting too much water and the mold seems to be a problem too, but I'm an absolute beginner on this.
Here is a to the pots that I got [big one](https://www.youtube.com/watch?v=YJjxPZagf7Y) (there is a stack in the video but i only have the bottom one), and [the small ones](https://www.youtube.com/watch?v=ZCXy-TayLI8).
As per request, following are some pictures:
[](https://i.stack.imgur.com/yMZkv.jpg)
[](https://i.stack.imgur.com/0PRg0.jpg) | 2017/01/21 | [
"https://gardening.stackexchange.com/questions/30546",
"https://gardening.stackexchange.com",
"https://gardening.stackexchange.com/users/16552/"
] | 
This is my DIY self watering container, or sub irrigation planter, based on Larry Walls ideas. It's a kiddie pool with overflow holes drilled at 2 inches, with two grow bags (one's a Walmart bag used because it purportedly has low lead content) filled with potting mix and some compost. The stones are there to stop mosquitoes breeding.
If you can't get at the reservoir easily, you can install a watering pipe that leads directly to the reservoir so that you avoid watering the soil surface. See top right. I'm not sure why my spouse has placed the drink bottle with ceramic probe there as it's not needed. This planter has an overflow hole so I know when to stop filling it.
This is a commercial self watering pot with a watering tube. It has a float so that you can see the water level at a glance.
The point of a self watering planter is to ensure that the roots always have access to a water source, and you avoid watering the surface which promotes weeds growing, and fungi. So you must use a freely draining soil mix, and not soil which could become water logged causing the issues you see. If you're still seeing mold with the right mix then you haven't got enough ventilation and light to your plants. | I have two selfwatering pots, the grey version of [this](http://www.dedeman.ro/cluj-napoca/jardiniera-verbena-cu-tava-40cm-maro/p/7033597) or [this](http://www.dedeman.ro/cluj-napoca/jardiniera-verbena-cu-tava-40cm-alba/p/7033595). The images in the links will be enlarged when you point your mouse on them. The problem I had was that the tray and the pot where bound together really well. The tray had a plastic handle at each end that fit closely in the holes at the edges of the pot, making it very difficult to separate in order to put water in the tray because the pot was pretty heavy with soil and plants.
When the tray had some water in it and I was trying to take it out because I didn't know if all of it was consumed by the plants, the water would spill. When I was lucky to have all the water consumed at the moment of taking the tray out, the pot would be shaken pretty hard, and the stems of the plants with it.
This situation has lead me to water the plants from above and both pots started to show mold. The upper soil was dry, but deep inside the pot it was moist, not to mention that I never knew if there was water in the tray.
I had a pot with tulips and another one with basil and I had to throw away all the plants. I don't use these pots together with the trays anymore, only separated. Here is a picture of one of the trays. The pots were sent to somebody who has a garden this winter, that's why I can't take pictures.
[](https://i.stack.imgur.com/T83hq.jpg) |
30,546 | I got a big self watering pot with 3 different plants. After some weeks it got some mold (something like [this](https://gardening.stackexchange.com/questions/1562/my-indoor-plant-has-an-orange-mold-like-substance-growing-on-it-and-has-tiny-whi), but I got it earlier) in it and after trying some stuff in the internet I ended up changing the soil to stop the mold from growing.
In this pot there is a fern, a fittonia and succulent and I'm starting to think the fern is getting too much water.
I also got 3 other self-watering pots. One of them has an oregano, another has a small pepper and the last one has a cherry tomato. The oregano has some leaves with brown tips (I learned [here](https://www.youtube.com/watch?v=9gxnQNJopqg) that it might be overwatering), the pepper is not very good as well ([some pictures here](https://gardening.stackexchange.com/questions/30543/should-i-cut-off-the-withered-parts-of-my-pepper)), and the cherry tomato is not the best either.
I keep all those plants indoors, there is no direct sunlight but there is clarity.
Are those pots viable for this situation? I feel that my plants are getting too much water and the mold seems to be a problem too, but I'm an absolute beginner on this.
Here is a to the pots that I got [big one](https://www.youtube.com/watch?v=YJjxPZagf7Y) (there is a stack in the video but i only have the bottom one), and [the small ones](https://www.youtube.com/watch?v=ZCXy-TayLI8).
As per request, following are some pictures:
[](https://i.stack.imgur.com/yMZkv.jpg)
[](https://i.stack.imgur.com/0PRg0.jpg) | 2017/01/21 | [
"https://gardening.stackexchange.com/questions/30546",
"https://gardening.stackexchange.com",
"https://gardening.stackexchange.com/users/16552/"
] | 
This is my DIY self watering container, or sub irrigation planter, based on Larry Walls ideas. It's a kiddie pool with overflow holes drilled at 2 inches, with two grow bags (one's a Walmart bag used because it purportedly has low lead content) filled with potting mix and some compost. The stones are there to stop mosquitoes breeding.
If you can't get at the reservoir easily, you can install a watering pipe that leads directly to the reservoir so that you avoid watering the soil surface. See top right. I'm not sure why my spouse has placed the drink bottle with ceramic probe there as it's not needed. This planter has an overflow hole so I know when to stop filling it.
This is a commercial self watering pot with a watering tube. It has a float so that you can see the water level at a glance.
The point of a self watering planter is to ensure that the roots always have access to a water source, and you avoid watering the surface which promotes weeds growing, and fungi. So you must use a freely draining soil mix, and not soil which could become water logged causing the issues you see. If you're still seeing mold with the right mix then you haven't got enough ventilation and light to your plants. | I hate self watering anything to include those stupid gels they put in the potting soil. No way is this going to be better than just being there and being aware and watering when necessary. These pots don't care about the ambient temperature, the humidity, the drainage!! There are ways to deal with automatic watering but only ONLY for vacations. Even irrigation systems lead people to think plants like this autonomous watering. Then to have plants in pots without potting soil medium is just asking for trouble. ALL PLANTS IN POTS can not be watered by rain. PERIOD. My goodness. Never count on rain to water plants in pots. Sure, if you've got a deluge and your soil in your pots is soaked, then YOU make the decision to not water until that soil is dry, the pot when lifted is light!
And what I am seeing are too tiny of plants in too large of pots and soil. Big big problem! What is your soil? Do you have rocks, gravel at the bottom of the soil and above the BIG DRAINAGE HOLES in your 'pots'? Look up perched water tables. Watering is one of the simplest and easiest of all our interactions with our plants. Do not try to automate this otherwise you will be removed from your plants needs which are different from plant to plant.
You have got succulents planted with moisture loving plants (ferns)...how crazy is that? My goodness, those succulents need vastly different watering methods than do the ferns!! Plant like needs in one pot. Moisture lovers or shade lovers or sun lovers or shallow water for shallow rooted plants!! Until someone KNOWS their plants and their needs the last thing they should be doing is anything automated. I am not kidding! We humans try to do automated stuff with cash crops to make more production and we'd better have someone on duty all of the time to ensure those automated instructions are working correctly. The rest of us with plants should never do automated anything!! I am so serious. You have to be aware and vigilant and automation is for making cars not caring for plants! |
30,546 | I got a big self watering pot with 3 different plants. After some weeks it got some mold (something like [this](https://gardening.stackexchange.com/questions/1562/my-indoor-plant-has-an-orange-mold-like-substance-growing-on-it-and-has-tiny-whi), but I got it earlier) in it and after trying some stuff in the internet I ended up changing the soil to stop the mold from growing.
In this pot there is a fern, a fittonia and succulent and I'm starting to think the fern is getting too much water.
I also got 3 other self-watering pots. One of them has an oregano, another has a small pepper and the last one has a cherry tomato. The oregano has some leaves with brown tips (I learned [here](https://www.youtube.com/watch?v=9gxnQNJopqg) that it might be overwatering), the pepper is not very good as well ([some pictures here](https://gardening.stackexchange.com/questions/30543/should-i-cut-off-the-withered-parts-of-my-pepper)), and the cherry tomato is not the best either.
I keep all those plants indoors, there is no direct sunlight but there is clarity.
Are those pots viable for this situation? I feel that my plants are getting too much water and the mold seems to be a problem too, but I'm an absolute beginner on this.
Here is a to the pots that I got [big one](https://www.youtube.com/watch?v=YJjxPZagf7Y) (there is a stack in the video but i only have the bottom one), and [the small ones](https://www.youtube.com/watch?v=ZCXy-TayLI8).
As per request, following are some pictures:
[](https://i.stack.imgur.com/yMZkv.jpg)
[](https://i.stack.imgur.com/0PRg0.jpg) | 2017/01/21 | [
"https://gardening.stackexchange.com/questions/30546",
"https://gardening.stackexchange.com",
"https://gardening.stackexchange.com/users/16552/"
] | I have two selfwatering pots, the grey version of [this](http://www.dedeman.ro/cluj-napoca/jardiniera-verbena-cu-tava-40cm-maro/p/7033597) or [this](http://www.dedeman.ro/cluj-napoca/jardiniera-verbena-cu-tava-40cm-alba/p/7033595). The images in the links will be enlarged when you point your mouse on them. The problem I had was that the tray and the pot where bound together really well. The tray had a plastic handle at each end that fit closely in the holes at the edges of the pot, making it very difficult to separate in order to put water in the tray because the pot was pretty heavy with soil and plants.
When the tray had some water in it and I was trying to take it out because I didn't know if all of it was consumed by the plants, the water would spill. When I was lucky to have all the water consumed at the moment of taking the tray out, the pot would be shaken pretty hard, and the stems of the plants with it.
This situation has lead me to water the plants from above and both pots started to show mold. The upper soil was dry, but deep inside the pot it was moist, not to mention that I never knew if there was water in the tray.
I had a pot with tulips and another one with basil and I had to throw away all the plants. I don't use these pots together with the trays anymore, only separated. Here is a picture of one of the trays. The pots were sent to somebody who has a garden this winter, that's why I can't take pictures.
[](https://i.stack.imgur.com/T83hq.jpg) | I hate self watering anything to include those stupid gels they put in the potting soil. No way is this going to be better than just being there and being aware and watering when necessary. These pots don't care about the ambient temperature, the humidity, the drainage!! There are ways to deal with automatic watering but only ONLY for vacations. Even irrigation systems lead people to think plants like this autonomous watering. Then to have plants in pots without potting soil medium is just asking for trouble. ALL PLANTS IN POTS can not be watered by rain. PERIOD. My goodness. Never count on rain to water plants in pots. Sure, if you've got a deluge and your soil in your pots is soaked, then YOU make the decision to not water until that soil is dry, the pot when lifted is light!
And what I am seeing are too tiny of plants in too large of pots and soil. Big big problem! What is your soil? Do you have rocks, gravel at the bottom of the soil and above the BIG DRAINAGE HOLES in your 'pots'? Look up perched water tables. Watering is one of the simplest and easiest of all our interactions with our plants. Do not try to automate this otherwise you will be removed from your plants needs which are different from plant to plant.
You have got succulents planted with moisture loving plants (ferns)...how crazy is that? My goodness, those succulents need vastly different watering methods than do the ferns!! Plant like needs in one pot. Moisture lovers or shade lovers or sun lovers or shallow water for shallow rooted plants!! Until someone KNOWS their plants and their needs the last thing they should be doing is anything automated. I am not kidding! We humans try to do automated stuff with cash crops to make more production and we'd better have someone on duty all of the time to ensure those automated instructions are working correctly. The rest of us with plants should never do automated anything!! I am so serious. You have to be aware and vigilant and automation is for making cars not caring for plants! |
30,546 | I got a big self watering pot with 3 different plants. After some weeks it got some mold (something like [this](https://gardening.stackexchange.com/questions/1562/my-indoor-plant-has-an-orange-mold-like-substance-growing-on-it-and-has-tiny-whi), but I got it earlier) in it and after trying some stuff in the internet I ended up changing the soil to stop the mold from growing.
In this pot there is a fern, a fittonia and succulent and I'm starting to think the fern is getting too much water.
I also got 3 other self-watering pots. One of them has an oregano, another has a small pepper and the last one has a cherry tomato. The oregano has some leaves with brown tips (I learned [here](https://www.youtube.com/watch?v=9gxnQNJopqg) that it might be overwatering), the pepper is not very good as well ([some pictures here](https://gardening.stackexchange.com/questions/30543/should-i-cut-off-the-withered-parts-of-my-pepper)), and the cherry tomato is not the best either.
I keep all those plants indoors, there is no direct sunlight but there is clarity.
Are those pots viable for this situation? I feel that my plants are getting too much water and the mold seems to be a problem too, but I'm an absolute beginner on this.
Here is a to the pots that I got [big one](https://www.youtube.com/watch?v=YJjxPZagf7Y) (there is a stack in the video but i only have the bottom one), and [the small ones](https://www.youtube.com/watch?v=ZCXy-TayLI8).
As per request, following are some pictures:
[](https://i.stack.imgur.com/yMZkv.jpg)
[](https://i.stack.imgur.com/0PRg0.jpg) | 2017/01/21 | [
"https://gardening.stackexchange.com/questions/30546",
"https://gardening.stackexchange.com",
"https://gardening.stackexchange.com/users/16552/"
] | I don't like self watering containers either - I've never known one that works efficiently, supplying every plant's needs and no more, they invariably develop fungal problems in the soil, or the plant does. I can see why people buy them, but its not the best way to care for plants.
The other problem is your tomato, pepper and oregano - all three like a lot of sunlight, and they're not getting anything other than bright daylight by the sound of it. With regard to the Fittonia, Fern and unnamed succulent, these plants do not appear to be natural bedfellows, requiring different levels of moisture and possibly soil composition, but a photograph would be useful, if only to determine what the succulent is. | I have two selfwatering pots, the grey version of [this](http://www.dedeman.ro/cluj-napoca/jardiniera-verbena-cu-tava-40cm-maro/p/7033597) or [this](http://www.dedeman.ro/cluj-napoca/jardiniera-verbena-cu-tava-40cm-alba/p/7033595). The images in the links will be enlarged when you point your mouse on them. The problem I had was that the tray and the pot where bound together really well. The tray had a plastic handle at each end that fit closely in the holes at the edges of the pot, making it very difficult to separate in order to put water in the tray because the pot was pretty heavy with soil and plants.
When the tray had some water in it and I was trying to take it out because I didn't know if all of it was consumed by the plants, the water would spill. When I was lucky to have all the water consumed at the moment of taking the tray out, the pot would be shaken pretty hard, and the stems of the plants with it.
This situation has lead me to water the plants from above and both pots started to show mold. The upper soil was dry, but deep inside the pot it was moist, not to mention that I never knew if there was water in the tray.
I had a pot with tulips and another one with basil and I had to throw away all the plants. I don't use these pots together with the trays anymore, only separated. Here is a picture of one of the trays. The pots were sent to somebody who has a garden this winter, that's why I can't take pictures.
[](https://i.stack.imgur.com/T83hq.jpg) |
30,546 | I got a big self watering pot with 3 different plants. After some weeks it got some mold (something like [this](https://gardening.stackexchange.com/questions/1562/my-indoor-plant-has-an-orange-mold-like-substance-growing-on-it-and-has-tiny-whi), but I got it earlier) in it and after trying some stuff in the internet I ended up changing the soil to stop the mold from growing.
In this pot there is a fern, a fittonia and succulent and I'm starting to think the fern is getting too much water.
I also got 3 other self-watering pots. One of them has an oregano, another has a small pepper and the last one has a cherry tomato. The oregano has some leaves with brown tips (I learned [here](https://www.youtube.com/watch?v=9gxnQNJopqg) that it might be overwatering), the pepper is not very good as well ([some pictures here](https://gardening.stackexchange.com/questions/30543/should-i-cut-off-the-withered-parts-of-my-pepper)), and the cherry tomato is not the best either.
I keep all those plants indoors, there is no direct sunlight but there is clarity.
Are those pots viable for this situation? I feel that my plants are getting too much water and the mold seems to be a problem too, but I'm an absolute beginner on this.
Here is a to the pots that I got [big one](https://www.youtube.com/watch?v=YJjxPZagf7Y) (there is a stack in the video but i only have the bottom one), and [the small ones](https://www.youtube.com/watch?v=ZCXy-TayLI8).
As per request, following are some pictures:
[](https://i.stack.imgur.com/yMZkv.jpg)
[](https://i.stack.imgur.com/0PRg0.jpg) | 2017/01/21 | [
"https://gardening.stackexchange.com/questions/30546",
"https://gardening.stackexchange.com",
"https://gardening.stackexchange.com/users/16552/"
] | I don't like self watering containers either - I've never known one that works efficiently, supplying every plant's needs and no more, they invariably develop fungal problems in the soil, or the plant does. I can see why people buy them, but its not the best way to care for plants.
The other problem is your tomato, pepper and oregano - all three like a lot of sunlight, and they're not getting anything other than bright daylight by the sound of it. With regard to the Fittonia, Fern and unnamed succulent, these plants do not appear to be natural bedfellows, requiring different levels of moisture and possibly soil composition, but a photograph would be useful, if only to determine what the succulent is. | I hate self watering anything to include those stupid gels they put in the potting soil. No way is this going to be better than just being there and being aware and watering when necessary. These pots don't care about the ambient temperature, the humidity, the drainage!! There are ways to deal with automatic watering but only ONLY for vacations. Even irrigation systems lead people to think plants like this autonomous watering. Then to have plants in pots without potting soil medium is just asking for trouble. ALL PLANTS IN POTS can not be watered by rain. PERIOD. My goodness. Never count on rain to water plants in pots. Sure, if you've got a deluge and your soil in your pots is soaked, then YOU make the decision to not water until that soil is dry, the pot when lifted is light!
And what I am seeing are too tiny of plants in too large of pots and soil. Big big problem! What is your soil? Do you have rocks, gravel at the bottom of the soil and above the BIG DRAINAGE HOLES in your 'pots'? Look up perched water tables. Watering is one of the simplest and easiest of all our interactions with our plants. Do not try to automate this otherwise you will be removed from your plants needs which are different from plant to plant.
You have got succulents planted with moisture loving plants (ferns)...how crazy is that? My goodness, those succulents need vastly different watering methods than do the ferns!! Plant like needs in one pot. Moisture lovers or shade lovers or sun lovers or shallow water for shallow rooted plants!! Until someone KNOWS their plants and their needs the last thing they should be doing is anything automated. I am not kidding! We humans try to do automated stuff with cash crops to make more production and we'd better have someone on duty all of the time to ensure those automated instructions are working correctly. The rest of us with plants should never do automated anything!! I am so serious. You have to be aware and vigilant and automation is for making cars not caring for plants! |
206,094 | I've been working through a recent Computer Science homework involving recursion and big-O notation. I believe I understand this pretty well (certainly not perfectly, though!) But there is one question in particular that is giving me the most problems. The odd thing is that by looking it, it looks to be the most simple one on the homework.
Provide the best rate of growth using the big-Oh notation for the solution to the following recurrence?
T(1) = 2
T(n) = 2T(n - 1) + 1 for n>1
And the choices are:
* O(n log n)
* O(n^2)
* O(2^n)
* O(n^n)
I understand that big O works as an upper bound, to describe the most amount of calculations, or the highest running time, that program or process will take. I feel like this particular recursion should be O(n), since, at most, the recursion only occurs once for each value of n. Since n isn't available, it's either better than that, O(nlogn), or worse, being the other three options.
So, my question is: Why isn't this O(n)? | 2008/10/15 | [
"https://Stackoverflow.com/questions/206094",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/23323/"
] | There's a couple of different ways to solve recurrences: substitution, recurrence tree and master theorem. Master theorem won't work in the case, because it doesn't fit the master theorem form.
You could use the other two methods, but the easiest way for this problem is to solve it iteratively.
T(n) = 2T(n-1) + 1
T(n) = 4T(n-2) + 2 + 1
T(n) = 8T(n-3) + 4 + 2 + 1
T(n) = ...
See the pattern?
T(n) = 2n-1⋅T(1) + 2n-2 + 2n-3 + ... + 1
T(n) = 2n-1⋅2 + 2n-2 + 2n-3 + ... + 1
T(n) = 2n + 2n-2 + 2n-3 + ... + 1
Therefore, the tightest bound is Θ(2n). | >
> I think this will be exponential. Each increment to n brings twice as much calculation.
>
>
>
No, it doesn't. Quite on the contrary:
Consider that for *n* iterations, we get running time *R*. Then for *n* + 1 iterations we'll get exactly *R* + 1.
Thus, the growth rate is constant and the overall runtime is indeed *O*(*n*).
However, I think Dima's assumption about the question is right although his solution is overly complicated:
>
> What you have to do is to come up with a closed form solution, i. e. the non-recursive formula for T(n), and then determine what the big-O of that expression is.
>
>
>
It's sufficient to examine the relative size of *T*(*n*) and *T*(*n* + 1) iterations and determine the relative growth rate. The amount obviously doubles which directly gives the asymptotic growth. |
206,094 | I've been working through a recent Computer Science homework involving recursion and big-O notation. I believe I understand this pretty well (certainly not perfectly, though!) But there is one question in particular that is giving me the most problems. The odd thing is that by looking it, it looks to be the most simple one on the homework.
Provide the best rate of growth using the big-Oh notation for the solution to the following recurrence?
T(1) = 2
T(n) = 2T(n - 1) + 1 for n>1
And the choices are:
* O(n log n)
* O(n^2)
* O(2^n)
* O(n^n)
I understand that big O works as an upper bound, to describe the most amount of calculations, or the highest running time, that program or process will take. I feel like this particular recursion should be O(n), since, at most, the recursion only occurs once for each value of n. Since n isn't available, it's either better than that, O(nlogn), or worse, being the other three options.
So, my question is: Why isn't this O(n)? | 2008/10/15 | [
"https://Stackoverflow.com/questions/206094",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/23323/"
] | I think you have misunderstood the question a bit. It does not ask you how long it would take to solve the recurrence. It is asking what the big-O (the asymptotic bound) of the solution itself is.
What you have to do is to come up with a closed form solution, i. e. the non-recursive formula for T(n), and then determine what the big-O of that expression is. | >
> I think this will be exponential. Each increment to n brings twice as much calculation.
>
>
>
No, it doesn't. Quite on the contrary:
Consider that for *n* iterations, we get running time *R*. Then for *n* + 1 iterations we'll get exactly *R* + 1.
Thus, the growth rate is constant and the overall runtime is indeed *O*(*n*).
However, I think Dima's assumption about the question is right although his solution is overly complicated:
>
> What you have to do is to come up with a closed form solution, i. e. the non-recursive formula for T(n), and then determine what the big-O of that expression is.
>
>
>
It's sufficient to examine the relative size of *T*(*n*) and *T*(*n* + 1) iterations and determine the relative growth rate. The amount obviously doubles which directly gives the asymptotic growth. |
206,094 | I've been working through a recent Computer Science homework involving recursion and big-O notation. I believe I understand this pretty well (certainly not perfectly, though!) But there is one question in particular that is giving me the most problems. The odd thing is that by looking it, it looks to be the most simple one on the homework.
Provide the best rate of growth using the big-Oh notation for the solution to the following recurrence?
T(1) = 2
T(n) = 2T(n - 1) + 1 for n>1
And the choices are:
* O(n log n)
* O(n^2)
* O(2^n)
* O(n^n)
I understand that big O works as an upper bound, to describe the most amount of calculations, or the highest running time, that program or process will take. I feel like this particular recursion should be O(n), since, at most, the recursion only occurs once for each value of n. Since n isn't available, it's either better than that, O(nlogn), or worse, being the other three options.
So, my question is: Why isn't this O(n)? | 2008/10/15 | [
"https://Stackoverflow.com/questions/206094",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/23323/"
] | There's a couple of different ways to solve recurrences: substitution, recurrence tree and master theorem. Master theorem won't work in the case, because it doesn't fit the master theorem form.
You could use the other two methods, but the easiest way for this problem is to solve it iteratively.
T(n) = 2T(n-1) + 1
T(n) = 4T(n-2) + 2 + 1
T(n) = 8T(n-3) + 4 + 2 + 1
T(n) = ...
See the pattern?
T(n) = 2n-1⋅T(1) + 2n-2 + 2n-3 + ... + 1
T(n) = 2n-1⋅2 + 2n-2 + 2n-3 + ... + 1
T(n) = 2n + 2n-2 + 2n-3 + ... + 1
Therefore, the tightest bound is Θ(2n). | I think you have misunderstood the question a bit. It does not ask you how long it would take to solve the recurrence. It is asking what the big-O (the asymptotic bound) of the solution itself is.
What you have to do is to come up with a closed form solution, i. e. the non-recursive formula for T(n), and then determine what the big-O of that expression is. |
99,922 | I have a player in my game who is playing a DEX based monk. He is using an Amulet of Mighty Fists with Agile Magic Weapon ability to aid with damage and weapon finese to hit.
He is planning on going into Dragon Style, which grants a plus 1.5 bonus to STR damage on your first unarmed attack.
First would this be wasted or would it be converted to Dex naturally and if not is there a feat or trait that allows him to swap those? | 2017/05/16 | [
"https://rpg.stackexchange.com/questions/99922",
"https://rpg.stackexchange.com",
"https://rpg.stackexchange.com/users/31670/"
] | The description of the agile property reads:
>
> Agile weapons are unusually well balanced and responsive. A wielder with the Weapon Finesse feat can choose to apply her Dexterity modifier to damage rolls with an agile weapon in place of her Strength modifier. **This modifier to damage is not increased for two-handed weapons, but is still reduced for off-hand weapons.**
> (emphasis added)
>
>
>
Since the text here specifically says that the modifier to damage doesn't increase when using a two-handed weapon like it would when using your Str bonus, I would argue that the *agile* property is incompatible with Dragon Style in this regard.
On the other hand, [this FAQ item](http://paizo.com/paizo/faq/v5748nruor1h3#v5748eaic9tb7) clarifies that an Unchained Rogue using Finesse Training with a two-handed weapon gains 1.5 \* Dex to damage. In that case, I think Dragon Style could be used to increase your damage bonus from Dex. So while I wouldn't expect to get away with it in Pathfinder Society play, I think you could reasonably rule to allow using Dragon Style to increase your Dex bonus to damage in your game specifically.
However you rule about using Dex for the damage portion of Dragon Style, though, I don't think that the monk can use his Dex modifier instead of his Str modifier to increase the duration of the shaken effect from Dragon Ferocity, since that isn't a form of damage. | For the swap attribute question, [this gdoc](https://docs.google.com/document/d/1o91Z-s0R7Vf2Ujj1lFqGC5W--9JOyU0I6uC9XRIR5to/edit) contains useful informations (even if it's less and less up-to-date). Looking at it you can find feats that could have worked (like Slashing Grace), but doesn't since erratas. The Agile property seems to be the only way to get that without spending levels in an other class (e.g. three levels of unchained rogue).
Considering the interaction between the two effects, it can arguably been read in different ways ([the discussion linked by Phlyk](http://paizo.com/threads/rzs2q7tt?Dragon-Style-and-Agile-Weapon-Enhancment) gives a good averall of the different points of view), so the DM will have to decide. Personally I would rule for the two effect to result in 1.5 times the Dexterity bonus to damage, because it doesn't break the game and the Monk is not an OP class to start with. |
492,971 | The ink of my Canon PIXMA MP280 all-in-one inkjet printer just ran out and I realized that not only I cannot print but I cannot scan (which doesn't need any ink, of course).
Upon making some further research it seems to me that it's a general practice on the behalf of all-in-one inkjet printer manufacturers to block the scanning function in order to "motivate" users to buy a new cartridge as soon as possible.
1) Is this true?
As a conscious buyer in the future I'd rather like to reward manufacturers that place the interests of their customers before their profit and allow scanning even when the cartridge is empty.
2) Does anyone know about any such manufacturers? | 2012/10/25 | [
"https://superuser.com/questions/492971",
"https://superuser.com",
"https://superuser.com/users/136683/"
] | The scanner in my HP F4280 AIO (admittedly somewhat dated, but not *all* that old) will work as long as actual cartridges are inserted into the printer and recognized as such, no matter what their ink level is.
However, don't take this as general advice that HP AIOs all behave like this. They might decide to change it at any time.
Furthermore, asking for specific manufacturers or products that support certain features is a shopping recommendation question and is probably off-topic.
I do not doubt your assertion that your Canon refuses to scan with no ink cartridges or when they are empty. This could be a simple programming oversight (a mistake), or it could be intentional. Unless you asked the original designers, it's hard to tell why exactly this happens. The intention isn't really important; what matters are the results. The fact is that you can't scan with this AIO while you don't have ink, which is a rather severe limitation.
Of course, if you're really in doubt, just buy a dedicated scanner and a separate printer. You'll never have to replace your scanner, unless you wear out the moving parts, or need a higher DPI; but in general they should last a very long time. | EASY ! On your printer HOLD "stop" button until it clears the error. Done . You can use your scanner . Just try not to use your printer to print or you can damage it with low or missing ink. |
4,026,130 | A client do not want to consider MonoTouch for a new project.
[MonoTouch.info](http://monotouch.info/MonoTouch/Apps) has a long list of apps, but I have not found any on the caliber that can convince a client too choose a technology. The client has seen the list, and actually use the bland screenshots as an argument against MonoTouch.
Where can I find examples of applications useful as motivation. High profile apps created using MonoTouch, the apps you call home about. The apps that made it to the top 25 lists in their category.? | 2010/10/26 | [
"https://Stackoverflow.com/questions/4026130",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/165059/"
] | I responded on Twitter but thought I'd reply properly here;
The first app I will mention is iCircuit - <http://icircuitapp.com/> - this application is featured on the Apple website here - <http://www.apple.com/ipad/business/apps/index.html#workflow-icircuit> - and is a pretty good seller.
Diggify is a Digg application which hit the top #8 sold application in Canada apparently - <http://www.intomobile.com/apps/diggify/359756952/>
An application that I built myself (it's a little old now admittedly) but I do think that it looks rather nice - <http://bit.ly/gfxmasappstore> :)
London Bike App is another nice looking application - <http://www.londonbikeapp.com/>
**Update:** Wow, this is an old question, there's a whole bunch of great apps using MonoTouch at <http://xamarin.com/apps>
Hope this helps,
ChrisNTR | I know of a couple apps that were built using Monotouch and sold very well but due to the uncertainly surrounding the terms when MT first came out and later the 3.3.1 mess the devs didn't make a big fuss out of it. I suspect they aren't the only ones not publicizing what technology they used to make their app.
If your client is using a handful of screenshots on a website as the reason to rule out using Monotouch then you might want to rethink your pitch. Whether or not an app has been developed in native Objective-C or C# via Monotouch makes no difference on the overall design or appearance because both rely on the CocoaTouch framework for UI. Being able to deliver an app that meets your client's idea of what makes a great app has nothing to do with the language you use and has everything to do with your ability to translate the essence of their ideas into a solid design and UX. Sell that, not the framework. |
4,026,130 | A client do not want to consider MonoTouch for a new project.
[MonoTouch.info](http://monotouch.info/MonoTouch/Apps) has a long list of apps, but I have not found any on the caliber that can convince a client too choose a technology. The client has seen the list, and actually use the bland screenshots as an argument against MonoTouch.
Where can I find examples of applications useful as motivation. High profile apps created using MonoTouch, the apps you call home about. The apps that made it to the top 25 lists in their category.? | 2010/10/26 | [
"https://Stackoverflow.com/questions/4026130",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/165059/"
] | I responded on Twitter but thought I'd reply properly here;
The first app I will mention is iCircuit - <http://icircuitapp.com/> - this application is featured on the Apple website here - <http://www.apple.com/ipad/business/apps/index.html#workflow-icircuit> - and is a pretty good seller.
Diggify is a Digg application which hit the top #8 sold application in Canada apparently - <http://www.intomobile.com/apps/diggify/359756952/>
An application that I built myself (it's a little old now admittedly) but I do think that it looks rather nice - <http://bit.ly/gfxmasappstore> :)
London Bike App is another nice looking application - <http://www.londonbikeapp.com/>
**Update:** Wow, this is an old question, there's a whole bunch of great apps using MonoTouch at <http://xamarin.com/apps>
Hope this helps,
ChrisNTR | I found this article to be helpful when I'm trying to explain to others why I use Monotouch over native objective-c.
["Why we chose MonoTouch to write the Diggify iPhone app"](http://simon.nureality.ca/simon-says-why-we-chose-monotouch-to-write-the-diggify-iphone-app/) |
4,026,130 | A client do not want to consider MonoTouch for a new project.
[MonoTouch.info](http://monotouch.info/MonoTouch/Apps) has a long list of apps, but I have not found any on the caliber that can convince a client too choose a technology. The client has seen the list, and actually use the bland screenshots as an argument against MonoTouch.
Where can I find examples of applications useful as motivation. High profile apps created using MonoTouch, the apps you call home about. The apps that made it to the top 25 lists in their category.? | 2010/10/26 | [
"https://Stackoverflow.com/questions/4026130",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/165059/"
] | I know of a couple apps that were built using Monotouch and sold very well but due to the uncertainly surrounding the terms when MT first came out and later the 3.3.1 mess the devs didn't make a big fuss out of it. I suspect they aren't the only ones not publicizing what technology they used to make their app.
If your client is using a handful of screenshots on a website as the reason to rule out using Monotouch then you might want to rethink your pitch. Whether or not an app has been developed in native Objective-C or C# via Monotouch makes no difference on the overall design or appearance because both rely on the CocoaTouch framework for UI. Being able to deliver an app that meets your client's idea of what makes a great app has nothing to do with the language you use and has everything to do with your ability to translate the essence of their ideas into a solid design and UX. Sell that, not the framework. | I found this article to be helpful when I'm trying to explain to others why I use Monotouch over native objective-c.
["Why we chose MonoTouch to write the Diggify iPhone app"](http://simon.nureality.ca/simon-says-why-we-chose-monotouch-to-write-the-diggify-iphone-app/) |
35,778,556 | Very newbie question I assume.. I started playing around with ES and MongoDB and I'm trying to move data out a SQL DB as an exercise.
I can't help but wonder, what data would I store in Mongo and what in ES? Can I store everything in ES? Assume *big* data load, as in price trends. | 2016/03/03 | [
"https://Stackoverflow.com/questions/35778556",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/5721688/"
] | To begin with, MongoDB is so-called a document store. Key feature of such concept is that is stores schema-dynamic documents:
* Each record in a document collection can have a different structure
* Types of each records can be different
* Document properties (columns) can have nested structures
It's not schema-free, it's schema-dynamic (or flexible schema). To get into the concept, you can find a great tutorial here: <https://docs.mongodb.org/manual/data-modeling/>
MongoDB is the most widely used document store - please, see <http://db-engines.com/en/system/MongoDB>.
It has "drivers" for most programming languages, enabling rapid development. You can dive into Mongo quite quickly, there are a lot of tutorials and official Mongo University - a great course for developers and DBAs.
In short terms it supports indexing, aggregations, filters, load balancing, sharding, replications (replica sets) etc. Data is stored and transferred in a BSON format (<http://bsonspec.org/>).
A good comparison of MongoDB vs RDBMS concepts can be found in this official reference: <https://docs.mongodb.org/manual/reference/sql-comparison/>
What is it good for? It enables agile development, where schema can change over a period of time, especially form based data, user generated content, location based data, user profiles and more. It also enables storing large documents (up to 16MB each).
Now, Elasticsearch is not a database. It is a search engine with some great aggregation capabilities (<https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations.html> - make sure you check out Metrics, Buckets and Pipeline aggregations).
Typical RDBSM is not designed for full-text searches or loosely structured data. Queries in ES can return results much faster than any database (e.g. seconds in RDBMS compared to milliseconds in ES). You need to remember that a key is to design indexes well, and that they will take your disk space.
There is a very detailed article comparing both in regards to performance, you may find it useful: <http://blog.quarkslab.com/mongodb-vs-elasticsearch-the-quest-of-the-holy-performances.html>.
You can actually use both successfully - MongoDB will store your data, where ES will be used as serving layer (search, aggregations etc.). | There is a big difference between mongodb and ES.
MongoDB is a database which was design in order to store data in it and query thats, while elasticsearch is an lucene base indexer in which you should only index data for searches and should not trust elastisearch. even though you can use store:true in elastic search, it is not recommended and i wouldn't rely on that for important data. |
1,430,508 | I made an employee handbook (booklet format) now I want to add two normal page documents (sign-off docs.) to the end of the booklet so that everything is in one file ready to print. I have tried copy and paste and the sign-off pages convert to half sheets size (booklet) or if I use keep formatting the entire booklet changes to normal page size. I also tried to use the page set-up and change to 'from this point forward' and again the booklet format is removed. Any ideas? is this even possible? | 2019/04/28 | [
"https://superuser.com/questions/1430508",
"https://superuser.com",
"https://superuser.com/users/1028669/"
] | ### Is there a way to bypass/overcome this?
Yes.
>
> **Can I turn off Safelinks?**
>
>
> To provide the best protection for your account, Safelinks are on by
> default. You can turn them off by signing in to
> [https://outlook.live.com](https://outlook.live.com/). Then select Settings > Premium >
> Security. There's a toggle under Advanced Security that you can use to
> turn off Safelinks. Note that turning off Safelinks will only affect
> future messages you receive. It won't change the link format in
> messages you've already received.
>
>
>
Source[Advanced Outlook.com security for Office 365 subscribers - Outlook](https://support.office.com/en-gb/article/advanced-outlook-com-security-for-office-365-subscribers-882d2243-eab9-4545-a58a-b36fee4a46e2) | In a corporate environment, Safelink (ATP) feature can NOT been disabled by employees. This is a disaster, because in all e-mails replies, the personalized bandworm URLs are included.
In the URL starting with <https://che01.safelinks.protection.outlook.com/?..>.
there is also the individual e-mail-address of employee included.
That is an absolute NoGo (privacy, tracking) and destroys the intention with tiny/simple URLs, which might be quite relevant for the e-mail receiver. |
11,792,931 | I need to compare Bikram Sambat dates in PHP. Lets say today in AD is 2012-08-03, the BS date today is 2069-04-19. In BS, we have total number of days in a month ranging from 29 to 32. Again, the days are not consistent in every year. Example if this year current month have 31 days, next year same month might have 30 or even 32 days.
The way i could think is, using a php date converter class (which I already have), convert given BS Dates to equivalent AD Dates and compare them. Just i want to know is there any other better way to do this without using the class i have??
By saying comparing here I mean
a) Finding days between the given date ranges.
b) Checking whether a date lies on a given two date ranges
c) And other comparisons we could do with AD dates using php Date Function
thanks any help is highly appreciated. | 2012/08/03 | [
"https://Stackoverflow.com/questions/11792931",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/744987/"
] | Generally, I would suggest converting both dates to unix timestamps (seconds since 1970-1-1 AD) which is a simple integer value for comparison.
Apparently, there is no simple logic behind BS so you will not be able to find an analytic expression that directly gets you from here to there. If you do not wish to use an external class you could write some sort of (recursive) function that starts from 1970-1-1 AD which you manually convert to BS and counts up the timestamp from there following the rules for BS. | Have a look at the source code of [KashmirStamps.ca/Samvat.html](http://www.kashmirstamps.ca/Samvat.html)
It is converting BS Dates to AD dates. You will find Javascript Code & Logic. You can easily adapt the logic to PHP code. |
44,865 | I was rewatching *The Age of Adaline* and I got a little bit confused. What's the age of Adaline Bowman's daughter Flemming Prescott in the movie? She is aging normally and we eventually see her age ahead of her mother. The Narrator does mention Adaline doesn't age for the next 60 or 70 years. By that estimate wouldn't her daughter have already died? | 2015/12/16 | [
"https://movies.stackexchange.com/questions/44865",
"https://movies.stackexchange.com",
"https://movies.stackexchange.com/users/28793/"
] | The locket wasn't needed to complete the ship, but it's symbolic in that it shows **Joe is finally willing to let the past go and embrace his future without his mom.** | If I remember correctly, when the alien had Joe in his arms, he told it something to the effect of that he knew a lot of bad things happened to it, but that it needed to let it go or something to that effect. So when the alien was drawing metal to the ship, it specifically chose the necklace as a way of saying the same thing to Joe. |
68,158 | In *Hacksaw Ridge* the Japanese just let the American soldiers climb up and there appeared to be no defence. The American soldiers were absolutely safe once they climbed down the ridge. The Japanese could shoot since they occupied a higher elevation. So why didn't they cut the ropes? | 2017/02/06 | [
"https://movies.stackexchange.com/questions/68158",
"https://movies.stackexchange.com",
"https://movies.stackexchange.com/users/29171/"
] | Keep in mind the movie is based on true events and there can be all kinds of reasons they didn't cut the ropes given the chaos of war and strategic motives of the different sides.
The Battle of Okinawa is known to be one of the bloodiest battles of the Pacific War and the key attack points were the beach and the ridges. The movie makes it seem like the rope ladder was abandoned and left with two guys to guard it at certain points. I find this highly unlikely. *If the US took the time to put a mesh rope ladder up, they would leave enough forces to defend it.* Any Japanese soldiers that came close enough to the ridge to attempt to cut it would have been gunned down. That said, its very possible that they DID attempt to cut the ropes down and its very possible that they succeeded in some of these attempts.
Ultimately, whether they attempted to cut the ropes or not is a detail not important to the movie's plot.
**We are meant to suspend our reality and assume that if any attempts were made to cut the rope, they either failed or were remedied by putting it back up.** | Simple answer the Japanese built that rope latter to get on the hill. However that hill is one way up and down whatever food and supplies the Japanese would get came from the rope so they can't cut it since that is there supply chain. Also why cut the rope if it's a one way up and down. It's make it easy for ambushing since you have the exact location that the enemy forces are coming from. This is all what war is ambushing and counter ambushing. |
68,158 | In *Hacksaw Ridge* the Japanese just let the American soldiers climb up and there appeared to be no defence. The American soldiers were absolutely safe once they climbed down the ridge. The Japanese could shoot since they occupied a higher elevation. So why didn't they cut the ropes? | 2017/02/06 | [
"https://movies.stackexchange.com/questions/68158",
"https://movies.stackexchange.com",
"https://movies.stackexchange.com/users/29171/"
] | Keep in mind the movie is based on true events and there can be all kinds of reasons they didn't cut the ropes given the chaos of war and strategic motives of the different sides.
The Battle of Okinawa is known to be one of the bloodiest battles of the Pacific War and the key attack points were the beach and the ridges. The movie makes it seem like the rope ladder was abandoned and left with two guys to guard it at certain points. I find this highly unlikely. *If the US took the time to put a mesh rope ladder up, they would leave enough forces to defend it.* Any Japanese soldiers that came close enough to the ridge to attempt to cut it would have been gunned down. That said, its very possible that they DID attempt to cut the ropes down and its very possible that they succeeded in some of these attempts.
Ultimately, whether they attempted to cut the ropes or not is a detail not important to the movie's plot.
**We are meant to suspend our reality and assume that if any attempts were made to cut the rope, they either failed or were remedied by putting it back up.** | According to the true story the Japanese wanted the Americans close to their hideout for tactical reasons. I guess that is part of the reason why they didn't cut the ropes. Another reason could be the exposure to the heavy artillery at sea. Also, according to the true story Desmond Doss was one of the volunteers to climb up and attach the ropes (not depicted in the movie). So it was mounted by the Americans, not the Japanese. |
68,158 | In *Hacksaw Ridge* the Japanese just let the American soldiers climb up and there appeared to be no defence. The American soldiers were absolutely safe once they climbed down the ridge. The Japanese could shoot since they occupied a higher elevation. So why didn't they cut the ropes? | 2017/02/06 | [
"https://movies.stackexchange.com/questions/68158",
"https://movies.stackexchange.com",
"https://movies.stackexchange.com/users/29171/"
] | According to the true story the Japanese wanted the Americans close to their hideout for tactical reasons. I guess that is part of the reason why they didn't cut the ropes. Another reason could be the exposure to the heavy artillery at sea. Also, according to the true story Desmond Doss was one of the volunteers to climb up and attach the ropes (not depicted in the movie). So it was mounted by the Americans, not the Japanese. | Simple answer the Japanese built that rope latter to get on the hill. However that hill is one way up and down whatever food and supplies the Japanese would get came from the rope so they can't cut it since that is there supply chain. Also why cut the rope if it's a one way up and down. It's make it easy for ambushing since you have the exact location that the enemy forces are coming from. This is all what war is ambushing and counter ambushing. |
68,158 | In *Hacksaw Ridge* the Japanese just let the American soldiers climb up and there appeared to be no defence. The American soldiers were absolutely safe once they climbed down the ridge. The Japanese could shoot since they occupied a higher elevation. So why didn't they cut the ropes? | 2017/02/06 | [
"https://movies.stackexchange.com/questions/68158",
"https://movies.stackexchange.com",
"https://movies.stackexchange.com/users/29171/"
] | You can find the answer in many accounts of the specific battle and I recommend watching the documentary on Doss, *The Conscientious Objector*. It is true that Doss was one of the ones tasked with securing the nets in the first place.
The ridge is much shorter than depicted in the movie and the terrain below it is far from flat so Japanese positions on the hill had a clear view of American movements all the way down to the landing zone. The only time that American troops could not be seen was right at the base of the ridge.
According to survivors anyone sent up to the top of the ridge for reconnaissance prior to securing the nets that was shot and killed. However, in accordance with Japanese tactics at the time, once it was clear what the Americans were doing, the Japanese soldiers waited until a concentration of troops had made it to the top before they opened fire. This was to ensure the maximum amount of casualties and that's pretty much what they did every time the Americans tried to secure the ridge--up to eight or nine times.
As long as those nets remained, the Japanese suspected the Americans would keep using them and putting large numbers of troops right in their line of fire. Though not always followed, this strategy was used in the hopes that the Americans would get tired of the fighting and offer a negotiated peace. Instead it convinced the US that an invasion of Japan would be too costly and the atomic bomb should be used instead. For what is probably the most comprehensive view of the battle from the Japanese perspective, I suggest *The Battle for Okinawa* by Colonel Hiromichi Yahara. | Simple answer the Japanese built that rope latter to get on the hill. However that hill is one way up and down whatever food and supplies the Japanese would get came from the rope so they can't cut it since that is there supply chain. Also why cut the rope if it's a one way up and down. It's make it easy for ambushing since you have the exact location that the enemy forces are coming from. This is all what war is ambushing and counter ambushing. |
68,158 | In *Hacksaw Ridge* the Japanese just let the American soldiers climb up and there appeared to be no defence. The American soldiers were absolutely safe once they climbed down the ridge. The Japanese could shoot since they occupied a higher elevation. So why didn't they cut the ropes? | 2017/02/06 | [
"https://movies.stackexchange.com/questions/68158",
"https://movies.stackexchange.com",
"https://movies.stackexchange.com/users/29171/"
] | You can find the answer in many accounts of the specific battle and I recommend watching the documentary on Doss, *The Conscientious Objector*. It is true that Doss was one of the ones tasked with securing the nets in the first place.
The ridge is much shorter than depicted in the movie and the terrain below it is far from flat so Japanese positions on the hill had a clear view of American movements all the way down to the landing zone. The only time that American troops could not be seen was right at the base of the ridge.
According to survivors anyone sent up to the top of the ridge for reconnaissance prior to securing the nets that was shot and killed. However, in accordance with Japanese tactics at the time, once it was clear what the Americans were doing, the Japanese soldiers waited until a concentration of troops had made it to the top before they opened fire. This was to ensure the maximum amount of casualties and that's pretty much what they did every time the Americans tried to secure the ridge--up to eight or nine times.
As long as those nets remained, the Japanese suspected the Americans would keep using them and putting large numbers of troops right in their line of fire. Though not always followed, this strategy was used in the hopes that the Americans would get tired of the fighting and offer a negotiated peace. Instead it convinced the US that an invasion of Japan would be too costly and the atomic bomb should be used instead. For what is probably the most comprehensive view of the battle from the Japanese perspective, I suggest *The Battle for Okinawa* by Colonel Hiromichi Yahara. | According to the true story the Japanese wanted the Americans close to their hideout for tactical reasons. I guess that is part of the reason why they didn't cut the ropes. Another reason could be the exposure to the heavy artillery at sea. Also, according to the true story Desmond Doss was one of the volunteers to climb up and attach the ropes (not depicted in the movie). So it was mounted by the Americans, not the Japanese. |
276,561 | I have found some answers, they are not correct, but accepted as correct answers.
How can we treat such answers. | 2014/11/11 | [
"https://meta.stackoverflow.com/questions/276561",
"https://meta.stackoverflow.com",
"https://meta.stackoverflow.com/users/2756205/"
] | Well here are things that you could do here:
1. Vote down the answer
2. Comment warnings why you think the answer is a mistake. (Author might edit it)
3. Give an alternative answer which you think is appropriate
Things you can't do
1. Edit the answer (Edit is for minor grammar, spelling or formatting problems only)
2. Ask someone to remove it as accepted answer (The inquirer of the question has full rights to accept an answer he/she sees fit, even if it is a mistake) | There are many questions on SO that are *incorrect* but *accepted*. The simplest thing that can be done is to down-vote the answer and then leave a comment to the question (so that the OP finds out) as well as the answer (so that the answerer finds out) that the accepted answer is wrong. I've been on either side of this :P. If you know the correct answer, then you could answer the question yourself :) |
52,816 | My sink backs up when running water for 3 min. Also into dishwasher.
It's also a double sink.
On the other hand, my dishwasher also backs up into sink.
This causes a disgusting smell through my home.
Especially in the bathroom and my bedroom.
I do have a basement, and when water backs up into sink ..it also backs up out of floor drain downstairs.
I had snake run through and it's not appearing to be stopped up.
New pipes were put in under sink and it didn't help.
Please give me something I can do.
I'm a single woman trying to figure this out. | 2014/11/14 | [
"https://diy.stackexchange.com/questions/52816",
"https://diy.stackexchange.com",
"https://diy.stackexchange.com/users/27933/"
] | It really sounds like the drain line blockage is beyond the place where the basement drain exits the foundation and goes off to either the public sewer system or private septic system. Could be broken underground line, line filled in with tree roots seeking water through joints or holes in the piping, or sediment / deposits in the line that have restricted its flow.
Probably the best way to troubleshoot this type of problem is to use a inspection camera that is slid through the pipe on the end of a long cable with a camera display at the end. Some professional plumbers have these for sewer inspection. It may also be possible to rent one and use it yourself but then you do not get the experienced eye of the operator knowing what nuances to look for. | The problem is in the street, or at least towards it, as Michael suggests. If you snaked it yourself I doubt it made it all the way to the street. If it was professionally snaked, start making phone calls to whoever did it and to the city.
[Jerseyville Sewage Plant](http://www.yellowpages.com/jerseyville-il/mip/jerseyville-sewage-plant-1195945). Call them and tell them your problem persists even after having your main line professionally snaked. If this is the wrong place perhaps they can point you in the right direction to contact your Streets and Sanitation department. |
32,234 | I admit that this observation is entirely subjective, but it seems to me that there three-bladed rotors are significantly less popular than two or four.
Factors that I'm guessing contribute -
* Storage - two-bladed helicopters take up a lot less space. So you're probably going to stick with two blades until you're compelled to move to four
* Simplicity - while an odd number of blades can be perfectly balanced, it may be easier to manufacture systems where the forces counter-balance in opposition rather than having to balance the entire system.
* Cost - two slightly longer blades are presumably a lot less expensive to maintain / purchase than three shorter ones.
These are guesses though. My question is - is my perception correct, and if so, why? | 2016/10/10 | [
"https://aviation.stackexchange.com/questions/32234",
"https://aviation.stackexchange.com",
"https://aviation.stackexchange.com/users/17435/"
] | Three bladed helicopters aren't rare. Many European small helicopters are three bladed:
* [Eurocopter Fennec](https://en.wikipedia.org/wiki/Eurocopter_Fennec)
* [Eurocopter AS355](https://en.wikipedia.org/wiki/Eurocopter_AS355)
* [Eurocopter Écureuil](https://en.wikipedia.org/wiki/Eurocopter_AS350_%C3%89cureuil)
* [PZL SW-4](https://en.wikipedia.org/wiki/PZL_SW-4)
* [Kamov Ka-226](https://en.wikipedia.org/wiki/Kamov_Ka-226)- it's coaxial, but still... Kamov has mostly used three blades for its coaxial helicopters.
* Most of the early small helicopters by the [Mil Design Bureau](https://en.wikipedia.org/wiki/Mil_Moscow_Helicopter_Plant) also had three blades, rather than two or four.
The Eurocopter helicopters show a pattern. They are developed from one another and trace their lineage from the [Aérospatiale Alouette II](https://en.wikipedia.org/wiki/A%C3%A9rospatiale_Alouette_II), [III](https://en.wikipedia.org/wiki/A%C3%A9rospatiale_Alouette_III) and [Aérospatiale Gazelle](https://en.wikipedia.org/wiki/A%C3%A9rospatiale_Gazelle)- all with three blades.
Most American smaller helicopters have teetering rotors, which default to two blades. This has been the case from [Bell 47](https://en.wikipedia.org/wiki/Bell_47) to [Bell UH-1 Iroquois](https://en.wikipedia.org/wiki/Bell_UH-1_Iroquois). Here again, the UH-1's transmission system was a development of the Bell 47. Again, if you're in US (or for training generally) , you'll be [seeing Robinsons](https://en.wikipedia.org/wiki/Robinson_R22), so it appears that there are almost no three bladed helicopters (with [Schweizer 300](https://en.wikipedia.org/wiki/Sikorsky_S-300) being an exception).
There are advantages and disadvantages in having different number of blades. In general, [the fewer, the better](https://aviation.stackexchange.com/questions/21354/possible-to-fly-with-counterbalanced-single-blade-engines). You pay for more lift, performance and (usually) less noise with mechanical complexity and less efficiency. It's a trade off.
Three versus four blades shows a clear geographical difference, due to the availability of engineers and their differing experience. | [Like with propellers](https://aviation.stackexchange.com/questions/13545/why-dont-aeroplanes-use-propellers-with-more-blades-like-the-intake-on-a-fanjet), the [blade count](https://aviation.stackexchange.com/questions/23009/what-are-the-advantages-of-more-than-4-propeller-blades) on a helicopter rotor is a matter of [disk loading](https://en.wikipedia.org/wiki/Disk_loading). Light helicopters get away with fewer blades. Complexity and losses increase with blade count, so helicopter designers try to fit as few blades as possible. However, this would result in huge rotor diameters for heavy helicopters. There are reasons to keep the diameter small:
* Blade root loads due to centrifugal forces
* Tip speed: The advancing blade will experience transsonic effects earlier if the helicopter flies in cruise the larger the rotor is. This will limit top flight speed.
* Blade bending on the ground. The blade needs to be stiff enough to clear the tail when the rotor spins up.
Now let's compare a few helicopters. I used the technical data on the linked Wikipedia page and divided the maximum take-off mass by the area of the rotor disk:
1. [Sud Aviation Aloutette II](https://en.wikipedia.org/wiki/A%C3%A9rospatiale_Alouette_II): 2-bladed rotor. Disk loading 19.6 kg/m². Disk loading per blade: 9.8 kg/m².
2. [Bell 205 / UH-1D](https://en.wikipedia.org/wiki/Bell_UH-1_Iroquois). 2-bladed rotor. Disk loading 25.6 kg/m². Disk loading per blade: 12.8 kg/m².
3. [Aérospatiale AS-350 Écureuil](https://en.wikipedia.org/wiki/Eurocopter_AS350_%C3%89cureuil): 3-bladed rotor. Disk loading 25.07 kg/m². Disk loading per blade: 8.36 kg/m².
4. [Bell 412](https://en.wikipedia.org/wiki/Bell_412): 4-bladed rotor. Disk loading 34.6 kg/m². Disk loading per blade: 8.65 kg/m².
5. [Sikorsky S-65 / CH-53](https://en.wikipedia.org/wiki/Sikorsky_CH-53_Sea_Stallion): 6-bladed rotor. Disk loading 50.2 kg/m². Disk loading per blade: 8.37 kg/m².
6. [Mil Mi-26](https://en.wikipedia.org/wiki/Mil_Mi-26): 8-bladed rotor. Disk loading 69.6 kg/m². Disk loading per blade: 8.7 kg/m².
I guess you see the trend by now. The UH-1D is the odd man out, but it also stands apart due to its unusually high blade chord. Normally, the ideal loading per blade seems to be between 8 and 9 kg/m², and a little more is deemed acceptable if it allows the designer to get away with only 2 blades.
There is no conspiracy to suppress three-bladed rotors. It's the overall compromise between performance and efficiency which determines the number of blades on a helicopter rotor, and the main driver is mass. |
32,234 | I admit that this observation is entirely subjective, but it seems to me that there three-bladed rotors are significantly less popular than two or four.
Factors that I'm guessing contribute -
* Storage - two-bladed helicopters take up a lot less space. So you're probably going to stick with two blades until you're compelled to move to four
* Simplicity - while an odd number of blades can be perfectly balanced, it may be easier to manufacture systems where the forces counter-balance in opposition rather than having to balance the entire system.
* Cost - two slightly longer blades are presumably a lot less expensive to maintain / purchase than three shorter ones.
These are guesses though. My question is - is my perception correct, and if so, why? | 2016/10/10 | [
"https://aviation.stackexchange.com/questions/32234",
"https://aviation.stackexchange.com",
"https://aviation.stackexchange.com/users/17435/"
] | Three bladed helicopters aren't rare. Many European small helicopters are three bladed:
* [Eurocopter Fennec](https://en.wikipedia.org/wiki/Eurocopter_Fennec)
* [Eurocopter AS355](https://en.wikipedia.org/wiki/Eurocopter_AS355)
* [Eurocopter Écureuil](https://en.wikipedia.org/wiki/Eurocopter_AS350_%C3%89cureuil)
* [PZL SW-4](https://en.wikipedia.org/wiki/PZL_SW-4)
* [Kamov Ka-226](https://en.wikipedia.org/wiki/Kamov_Ka-226)- it's coaxial, but still... Kamov has mostly used three blades for its coaxial helicopters.
* Most of the early small helicopters by the [Mil Design Bureau](https://en.wikipedia.org/wiki/Mil_Moscow_Helicopter_Plant) also had three blades, rather than two or four.
The Eurocopter helicopters show a pattern. They are developed from one another and trace their lineage from the [Aérospatiale Alouette II](https://en.wikipedia.org/wiki/A%C3%A9rospatiale_Alouette_II), [III](https://en.wikipedia.org/wiki/A%C3%A9rospatiale_Alouette_III) and [Aérospatiale Gazelle](https://en.wikipedia.org/wiki/A%C3%A9rospatiale_Gazelle)- all with three blades.
Most American smaller helicopters have teetering rotors, which default to two blades. This has been the case from [Bell 47](https://en.wikipedia.org/wiki/Bell_47) to [Bell UH-1 Iroquois](https://en.wikipedia.org/wiki/Bell_UH-1_Iroquois). Here again, the UH-1's transmission system was a development of the Bell 47. Again, if you're in US (or for training generally) , you'll be [seeing Robinsons](https://en.wikipedia.org/wiki/Robinson_R22), so it appears that there are almost no three bladed helicopters (with [Schweizer 300](https://en.wikipedia.org/wiki/Sikorsky_S-300) being an exception).
There are advantages and disadvantages in having different number of blades. In general, [the fewer, the better](https://aviation.stackexchange.com/questions/21354/possible-to-fly-with-counterbalanced-single-blade-engines). You pay for more lift, performance and (usually) less noise with mechanical complexity and less efficiency. It's a trade off.
Three versus four blades shows a clear geographical difference, due to the availability of engineers and their differing experience. | While the above answers have some correct points, they miss the fundamental points of the structure and function of the rotor hub differences in the two and four blade rotors versus the three blade rotors. Both have safety issues that are nuanced, and the difference can change the mission for a given helicopter.
Two and four blade rotors are most likely semi-rigid rotor hubs that are cantilevered off a fixed pin. That allows them move free up and down through the rotation that occurs from lead and lag forces. The limitation for these rotor hubs is that it has almost no tolerance to negative G-forces because negative Gs lead to mast bumping and airframe damage in air. Pushovers have to be very subtle. This requires special training specific to [SFAR 73](https://www.law.cornell.edu/cfr/text/14/appendix-SFAR_No_73).
Three bladed rotors have a fully articulated rotor head, which prevents mast bumping, so it has greater agility and can handle external cargo. These rotors handle lead-lag forces through hinges at the root of the rotor blade allowing the blade to move forward and aft relative to the direction of rotation throughout the revolution. The primary safety concern in these helicopters is touching down too hard or off balance jarring blades out of balance. If they do, gyroscopic forces react through the airframe, and if the helicopter is still touching the ground, that part touching the ground becomes the pivot point around which the airframe gyroscopic forces act flipping the helicopter over that pivot point. This is more likely on the three-bladed helicopters with skids instead of landing gear. The skids have shocks essentially to prevent the jarring, but if they're bottomed out or flat, the forces go through them unevenly. Helicopters with wheeled landing gear have less issue with that. Here is a good resource about [fully articulated rotor heads](http://www.iadc.org/wp-content/uploads/2014/02/sa-09-14.pdf).
Above 4 blades is when helicopters are looking to reduce noise, balance performance (both lifting capability and agility) and stability; and keeping the frequencies out of the pilot PIO and human factors frequencies become bigger issues. |
32,234 | I admit that this observation is entirely subjective, but it seems to me that there three-bladed rotors are significantly less popular than two or four.
Factors that I'm guessing contribute -
* Storage - two-bladed helicopters take up a lot less space. So you're probably going to stick with two blades until you're compelled to move to four
* Simplicity - while an odd number of blades can be perfectly balanced, it may be easier to manufacture systems where the forces counter-balance in opposition rather than having to balance the entire system.
* Cost - two slightly longer blades are presumably a lot less expensive to maintain / purchase than three shorter ones.
These are guesses though. My question is - is my perception correct, and if so, why? | 2016/10/10 | [
"https://aviation.stackexchange.com/questions/32234",
"https://aviation.stackexchange.com",
"https://aviation.stackexchange.com/users/17435/"
] | Three bladed helicopters aren't rare. Many European small helicopters are three bladed:
* [Eurocopter Fennec](https://en.wikipedia.org/wiki/Eurocopter_Fennec)
* [Eurocopter AS355](https://en.wikipedia.org/wiki/Eurocopter_AS355)
* [Eurocopter Écureuil](https://en.wikipedia.org/wiki/Eurocopter_AS350_%C3%89cureuil)
* [PZL SW-4](https://en.wikipedia.org/wiki/PZL_SW-4)
* [Kamov Ka-226](https://en.wikipedia.org/wiki/Kamov_Ka-226)- it's coaxial, but still... Kamov has mostly used three blades for its coaxial helicopters.
* Most of the early small helicopters by the [Mil Design Bureau](https://en.wikipedia.org/wiki/Mil_Moscow_Helicopter_Plant) also had three blades, rather than two or four.
The Eurocopter helicopters show a pattern. They are developed from one another and trace their lineage from the [Aérospatiale Alouette II](https://en.wikipedia.org/wiki/A%C3%A9rospatiale_Alouette_II), [III](https://en.wikipedia.org/wiki/A%C3%A9rospatiale_Alouette_III) and [Aérospatiale Gazelle](https://en.wikipedia.org/wiki/A%C3%A9rospatiale_Gazelle)- all with three blades.
Most American smaller helicopters have teetering rotors, which default to two blades. This has been the case from [Bell 47](https://en.wikipedia.org/wiki/Bell_47) to [Bell UH-1 Iroquois](https://en.wikipedia.org/wiki/Bell_UH-1_Iroquois). Here again, the UH-1's transmission system was a development of the Bell 47. Again, if you're in US (or for training generally) , you'll be [seeing Robinsons](https://en.wikipedia.org/wiki/Robinson_R22), so it appears that there are almost no three bladed helicopters (with [Schweizer 300](https://en.wikipedia.org/wiki/Sikorsky_S-300) being an exception).
There are advantages and disadvantages in having different number of blades. In general, [the fewer, the better](https://aviation.stackexchange.com/questions/21354/possible-to-fly-with-counterbalanced-single-blade-engines). You pay for more lift, performance and (usually) less noise with mechanical complexity and less efficiency. It's a trade off.
Three versus four blades shows a clear geographical difference, due to the availability of engineers and their differing experience. | In addition to the reasons stated in the other answers, there is still a bit more on the subject. Often, the number of blades incorporated into a rotor design is about blade/disk loading, load carrying, speed-performance. Many times the number of blades is driven by vibration / ride quality and noise.
In the case of 3 blade systems, rotor vibration and noise have multiples of 3/rev, 6/rev, 9/rev. 2 AND 4 bladed systems have multiples of 2/rev, 4,rev, 8/rev, 12/rev. Odd numbered systems rarely exhibit submultiples great enough to be of concern, while even numbered systems can cover the spectrum. Think 5 vs 6 blades. The 5 bladed MD500s are almost on par with fixed wing ride quality when properly tuned.
On the other hand, take the Bell 214/214ST. A big 2 bladed example. Even with nodal beam suspension to mitigate 2/rev, these beasts ride very harsh and can only be tuned for hover and one nominal cruise airspeed.
Regarding the subject of noise. In the late 80s Los Angeles County Fire Dept, against the better judgement of the pilots, were mandated to change from the 2 bladed, Bell 205A-1 merely for the reason of noise. They subsequently bought 4 bladed, Bell 412s who's performance numbers, on paper, were stated to be equal if not marginally better. The pilots always preferred the performance characteristics of the 2 blades systems. Been on many max gross takeoffs with LACO Fire from Barton heliport, in 2 and 4 blade ships. The pre-takeoff briefing in the 4 blade 412 was not without reference to the possibility of having to pickle the load during translational lift. |
32,234 | I admit that this observation is entirely subjective, but it seems to me that there three-bladed rotors are significantly less popular than two or four.
Factors that I'm guessing contribute -
* Storage - two-bladed helicopters take up a lot less space. So you're probably going to stick with two blades until you're compelled to move to four
* Simplicity - while an odd number of blades can be perfectly balanced, it may be easier to manufacture systems where the forces counter-balance in opposition rather than having to balance the entire system.
* Cost - two slightly longer blades are presumably a lot less expensive to maintain / purchase than three shorter ones.
These are guesses though. My question is - is my perception correct, and if so, why? | 2016/10/10 | [
"https://aviation.stackexchange.com/questions/32234",
"https://aviation.stackexchange.com",
"https://aviation.stackexchange.com/users/17435/"
] | [Like with propellers](https://aviation.stackexchange.com/questions/13545/why-dont-aeroplanes-use-propellers-with-more-blades-like-the-intake-on-a-fanjet), the [blade count](https://aviation.stackexchange.com/questions/23009/what-are-the-advantages-of-more-than-4-propeller-blades) on a helicopter rotor is a matter of [disk loading](https://en.wikipedia.org/wiki/Disk_loading). Light helicopters get away with fewer blades. Complexity and losses increase with blade count, so helicopter designers try to fit as few blades as possible. However, this would result in huge rotor diameters for heavy helicopters. There are reasons to keep the diameter small:
* Blade root loads due to centrifugal forces
* Tip speed: The advancing blade will experience transsonic effects earlier if the helicopter flies in cruise the larger the rotor is. This will limit top flight speed.
* Blade bending on the ground. The blade needs to be stiff enough to clear the tail when the rotor spins up.
Now let's compare a few helicopters. I used the technical data on the linked Wikipedia page and divided the maximum take-off mass by the area of the rotor disk:
1. [Sud Aviation Aloutette II](https://en.wikipedia.org/wiki/A%C3%A9rospatiale_Alouette_II): 2-bladed rotor. Disk loading 19.6 kg/m². Disk loading per blade: 9.8 kg/m².
2. [Bell 205 / UH-1D](https://en.wikipedia.org/wiki/Bell_UH-1_Iroquois). 2-bladed rotor. Disk loading 25.6 kg/m². Disk loading per blade: 12.8 kg/m².
3. [Aérospatiale AS-350 Écureuil](https://en.wikipedia.org/wiki/Eurocopter_AS350_%C3%89cureuil): 3-bladed rotor. Disk loading 25.07 kg/m². Disk loading per blade: 8.36 kg/m².
4. [Bell 412](https://en.wikipedia.org/wiki/Bell_412): 4-bladed rotor. Disk loading 34.6 kg/m². Disk loading per blade: 8.65 kg/m².
5. [Sikorsky S-65 / CH-53](https://en.wikipedia.org/wiki/Sikorsky_CH-53_Sea_Stallion): 6-bladed rotor. Disk loading 50.2 kg/m². Disk loading per blade: 8.37 kg/m².
6. [Mil Mi-26](https://en.wikipedia.org/wiki/Mil_Mi-26): 8-bladed rotor. Disk loading 69.6 kg/m². Disk loading per blade: 8.7 kg/m².
I guess you see the trend by now. The UH-1D is the odd man out, but it also stands apart due to its unusually high blade chord. Normally, the ideal loading per blade seems to be between 8 and 9 kg/m², and a little more is deemed acceptable if it allows the designer to get away with only 2 blades.
There is no conspiracy to suppress three-bladed rotors. It's the overall compromise between performance and efficiency which determines the number of blades on a helicopter rotor, and the main driver is mass. | While the above answers have some correct points, they miss the fundamental points of the structure and function of the rotor hub differences in the two and four blade rotors versus the three blade rotors. Both have safety issues that are nuanced, and the difference can change the mission for a given helicopter.
Two and four blade rotors are most likely semi-rigid rotor hubs that are cantilevered off a fixed pin. That allows them move free up and down through the rotation that occurs from lead and lag forces. The limitation for these rotor hubs is that it has almost no tolerance to negative G-forces because negative Gs lead to mast bumping and airframe damage in air. Pushovers have to be very subtle. This requires special training specific to [SFAR 73](https://www.law.cornell.edu/cfr/text/14/appendix-SFAR_No_73).
Three bladed rotors have a fully articulated rotor head, which prevents mast bumping, so it has greater agility and can handle external cargo. These rotors handle lead-lag forces through hinges at the root of the rotor blade allowing the blade to move forward and aft relative to the direction of rotation throughout the revolution. The primary safety concern in these helicopters is touching down too hard or off balance jarring blades out of balance. If they do, gyroscopic forces react through the airframe, and if the helicopter is still touching the ground, that part touching the ground becomes the pivot point around which the airframe gyroscopic forces act flipping the helicopter over that pivot point. This is more likely on the three-bladed helicopters with skids instead of landing gear. The skids have shocks essentially to prevent the jarring, but if they're bottomed out or flat, the forces go through them unevenly. Helicopters with wheeled landing gear have less issue with that. Here is a good resource about [fully articulated rotor heads](http://www.iadc.org/wp-content/uploads/2014/02/sa-09-14.pdf).
Above 4 blades is when helicopters are looking to reduce noise, balance performance (both lifting capability and agility) and stability; and keeping the frequencies out of the pilot PIO and human factors frequencies become bigger issues. |
32,234 | I admit that this observation is entirely subjective, but it seems to me that there three-bladed rotors are significantly less popular than two or four.
Factors that I'm guessing contribute -
* Storage - two-bladed helicopters take up a lot less space. So you're probably going to stick with two blades until you're compelled to move to four
* Simplicity - while an odd number of blades can be perfectly balanced, it may be easier to manufacture systems where the forces counter-balance in opposition rather than having to balance the entire system.
* Cost - two slightly longer blades are presumably a lot less expensive to maintain / purchase than three shorter ones.
These are guesses though. My question is - is my perception correct, and if so, why? | 2016/10/10 | [
"https://aviation.stackexchange.com/questions/32234",
"https://aviation.stackexchange.com",
"https://aviation.stackexchange.com/users/17435/"
] | [Like with propellers](https://aviation.stackexchange.com/questions/13545/why-dont-aeroplanes-use-propellers-with-more-blades-like-the-intake-on-a-fanjet), the [blade count](https://aviation.stackexchange.com/questions/23009/what-are-the-advantages-of-more-than-4-propeller-blades) on a helicopter rotor is a matter of [disk loading](https://en.wikipedia.org/wiki/Disk_loading). Light helicopters get away with fewer blades. Complexity and losses increase with blade count, so helicopter designers try to fit as few blades as possible. However, this would result in huge rotor diameters for heavy helicopters. There are reasons to keep the diameter small:
* Blade root loads due to centrifugal forces
* Tip speed: The advancing blade will experience transsonic effects earlier if the helicopter flies in cruise the larger the rotor is. This will limit top flight speed.
* Blade bending on the ground. The blade needs to be stiff enough to clear the tail when the rotor spins up.
Now let's compare a few helicopters. I used the technical data on the linked Wikipedia page and divided the maximum take-off mass by the area of the rotor disk:
1. [Sud Aviation Aloutette II](https://en.wikipedia.org/wiki/A%C3%A9rospatiale_Alouette_II): 2-bladed rotor. Disk loading 19.6 kg/m². Disk loading per blade: 9.8 kg/m².
2. [Bell 205 / UH-1D](https://en.wikipedia.org/wiki/Bell_UH-1_Iroquois). 2-bladed rotor. Disk loading 25.6 kg/m². Disk loading per blade: 12.8 kg/m².
3. [Aérospatiale AS-350 Écureuil](https://en.wikipedia.org/wiki/Eurocopter_AS350_%C3%89cureuil): 3-bladed rotor. Disk loading 25.07 kg/m². Disk loading per blade: 8.36 kg/m².
4. [Bell 412](https://en.wikipedia.org/wiki/Bell_412): 4-bladed rotor. Disk loading 34.6 kg/m². Disk loading per blade: 8.65 kg/m².
5. [Sikorsky S-65 / CH-53](https://en.wikipedia.org/wiki/Sikorsky_CH-53_Sea_Stallion): 6-bladed rotor. Disk loading 50.2 kg/m². Disk loading per blade: 8.37 kg/m².
6. [Mil Mi-26](https://en.wikipedia.org/wiki/Mil_Mi-26): 8-bladed rotor. Disk loading 69.6 kg/m². Disk loading per blade: 8.7 kg/m².
I guess you see the trend by now. The UH-1D is the odd man out, but it also stands apart due to its unusually high blade chord. Normally, the ideal loading per blade seems to be between 8 and 9 kg/m², and a little more is deemed acceptable if it allows the designer to get away with only 2 blades.
There is no conspiracy to suppress three-bladed rotors. It's the overall compromise between performance and efficiency which determines the number of blades on a helicopter rotor, and the main driver is mass. | In addition to the reasons stated in the other answers, there is still a bit more on the subject. Often, the number of blades incorporated into a rotor design is about blade/disk loading, load carrying, speed-performance. Many times the number of blades is driven by vibration / ride quality and noise.
In the case of 3 blade systems, rotor vibration and noise have multiples of 3/rev, 6/rev, 9/rev. 2 AND 4 bladed systems have multiples of 2/rev, 4,rev, 8/rev, 12/rev. Odd numbered systems rarely exhibit submultiples great enough to be of concern, while even numbered systems can cover the spectrum. Think 5 vs 6 blades. The 5 bladed MD500s are almost on par with fixed wing ride quality when properly tuned.
On the other hand, take the Bell 214/214ST. A big 2 bladed example. Even with nodal beam suspension to mitigate 2/rev, these beasts ride very harsh and can only be tuned for hover and one nominal cruise airspeed.
Regarding the subject of noise. In the late 80s Los Angeles County Fire Dept, against the better judgement of the pilots, were mandated to change from the 2 bladed, Bell 205A-1 merely for the reason of noise. They subsequently bought 4 bladed, Bell 412s who's performance numbers, on paper, were stated to be equal if not marginally better. The pilots always preferred the performance characteristics of the 2 blades systems. Been on many max gross takeoffs with LACO Fire from Barton heliport, in 2 and 4 blade ships. The pre-takeoff briefing in the 4 blade 412 was not without reference to the possibility of having to pickle the load during translational lift. |
420,680 | I had a bunch of questions bookmarked, but now I can't find them on my profile page. A quick Google search shows me results that are all from 2014 or prior. Where did they go? | 2022/10/04 | [
"https://meta.stackoverflow.com/questions/420680",
"https://meta.stackoverflow.com",
"https://meta.stackoverflow.com/users/19123103/"
] | Bookmarks are being turned into Saves. As written in the [MSE post](https://meta.stackexchange.com/q/382019/),
>
> The migration process will take some time to process as there are millions of bookmarked questions to migrate over. **If you’re not seeing any questions you previously bookmarked, that means they haven’t been processed yet.**
>
>
>
Give some time for the processing to complete.
---
Update Oct 5
Migration is paused temporarily and Bookmarks feature is turned back on. If your bookmarks are migrated(to saves), **they will NOT be available in bookmarks**. If they're not migrated, they will be available.
[MSE update says](https://meta.stackexchange.com/q/382019/):
>
> Saves has been temporarily disabled network-wide due to some site performance problems.
>
>
>
>
> Stack Overflow was the only site partially migrated
>
>
>
>
> Around 360k bookmarks were turned into saves
> Around 14mil bookmarks are still bookmarks
>
>
> | According to [the post TheMaster has linked to](https://meta.stackexchange.com/questions/382019/bookmarks-have-evolved-into-saves), I guess Bookmarks is being renamed Saves and is getting a bunch of new features such as creating a new lists (instead of a single bookmarks list) etc. The old bookmarks are meant be moved there but as [TheMaster mentioned](https://meta.stackoverflow.com/a/420681/19123103) (and also written in the FAQ section of [this post](https://meta.stackexchange.com/questions/382019/bookmarks-have-evolved-into-saves)), it's going to take time.
>
> **What will happen to my existing bookmarks?**
>
>
> We will be migrating over your existing bookmarks into the default
> “For later” Saves list. Once we enable the Saves feature, the
> migration process will take some time to process as there are millions
> of bookmarked questions to migrate over. If you’re not seeing any
> questions you previously bookmarked, that means they haven’t been
> processed yet.
>
>
>
Currently, it looks like this but the bookmarks are meant to appear here.
[](https://i.stack.imgur.com/x5rhW.png) |
13,769 | I'm trying to mine for slush's pool with GUIminer. The miner says that I am mining, and gives me a mhash number, but says that no matter how long I mine, I still have 0 shares.
The pool says that I have no mhash input to the pool.
Thanks in advance, bark | 2013/10/14 | [
"https://bitcoin.stackexchange.com/questions/13769",
"https://bitcoin.stackexchange.com",
"https://bitcoin.stackexchange.com/users/7094/"
] | I agree that you really don't want to be mining with your cpu. If this was with your gpu and this was happening, your debug output would probably involve a "check your hardware" error like the one many people got from the newest AMD SDK. That is fixed by rolling back drivers to the best compatible set.
You should look at the console by going to the menu bar: View > Show Console. Click the tab that pops up named Console and perhaps post a screenshot of that. | Try setting the server as "other" and typing in stratum.bitcoin.cz as the host and 3333 as the port. |
718,632 | I've been looking to improve my programming habits and I heard that OO is the way to go.
Also I'd much prefer online tutorials over books. | 2009/04/05 | [
"https://Stackoverflow.com/questions/718632",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/75173/"
] | Learning how to use classes, methods, and attributes is not sufficient for making you a good object oriented programmer. The other (and usually much more difficult) part is understanding how to solve problems in an object-oriented way.
It's a bit like chess: Even if you have memorized the rules perfectly, it does not mean you automatically are a good chess player. You still need to learn a about strategy and gather a lot of experience.
I haven't found a good web tutorial on how to become a good object-oriented programmer. The topic is too large to be covered within just a few web pages. You are probably better off reading a book on the subject. It doesn't even have to be specific to php, most OO pricinples can be applied to many different OO languages.
Once you have learned the basics of OO programming, I'd also recommend reading a book on design patterns such as the classic [Design Patterns](http://www.amazon.co.uk/Design-patterns-elements-reusable-object-oriented/dp/0201633612/ref=sr_1_1?ie=UTF8&s=books&qid=1238931499&sr=1-1) by Gamma et al. or the more casual [Head-First Design patterns](https://rads.stackoverflow.com/amzn/click/com/0596007124). | Not to be mean to Php, because it's quite good to get stuff done and fast, but Object Oriented Php is a non feature in my book, it's more productive to use Php as a procedural language, after all that's what it was made for, OOP is quite poor compared to other languages, same way I'd not use OOP with Perl either, if you want to learn OOP, which I totally recommend you use Ruby or Objective-C.
Anyways can't link but try googling for OMG (Object Management Group), they have tutorials and info about OOP on their site |
718,632 | I've been looking to improve my programming habits and I heard that OO is the way to go.
Also I'd much prefer online tutorials over books. | 2009/04/05 | [
"https://Stackoverflow.com/questions/718632",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/75173/"
] | Here are a few good tutorials from the PHP guys themselves.
* [PHP 101 (part 7): The Bear Necessities](http://devzone.zend.com/node/view/id/638)
* [The OO Evolution of PHP](http://devzone.zend.com/article/1717-The-OO-Evolution-of-PHP)
* [Using Objects to Create an Application](http://devzone.zend.com/article/1240-Using-Objects-to-Create-an-Application) | * [OO Tips](http://www.ootips.org/)
* [PHP Classes](http://www.phpclasses.org/)
* [OOP in PHP](http://www.devarticles.com/c/a/PHP/Object-Oriented-Programming-in-PHP/)
* and [Google](http://www.google.com/search?q=object%20oriented%20programming%20using%20php&hl=en&safe=off&client=firefox-a&rls=org.mozilla:en-US:official&hs=qGl&start=70&sa=N&cts=1238930053986) of course!
*OO is not a language-depended concept.* |
718,632 | I've been looking to improve my programming habits and I heard that OO is the way to go.
Also I'd much prefer online tutorials over books. | 2009/04/05 | [
"https://Stackoverflow.com/questions/718632",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/75173/"
] | Here are a few good tutorials from the PHP guys themselves.
* [PHP 101 (part 7): The Bear Necessities](http://devzone.zend.com/node/view/id/638)
* [The OO Evolution of PHP](http://devzone.zend.com/article/1717-The-OO-Evolution-of-PHP)
* [Using Objects to Create an Application](http://devzone.zend.com/article/1240-Using-Objects-to-Create-an-Application) | Learning how to use classes, methods, and attributes is not sufficient for making you a good object oriented programmer. The other (and usually much more difficult) part is understanding how to solve problems in an object-oriented way.
It's a bit like chess: Even if you have memorized the rules perfectly, it does not mean you automatically are a good chess player. You still need to learn a about strategy and gather a lot of experience.
I haven't found a good web tutorial on how to become a good object-oriented programmer. The topic is too large to be covered within just a few web pages. You are probably better off reading a book on the subject. It doesn't even have to be specific to php, most OO pricinples can be applied to many different OO languages.
Once you have learned the basics of OO programming, I'd also recommend reading a book on design patterns such as the classic [Design Patterns](http://www.amazon.co.uk/Design-patterns-elements-reusable-object-oriented/dp/0201633612/ref=sr_1_1?ie=UTF8&s=books&qid=1238931499&sr=1-1) by Gamma et al. or the more casual [Head-First Design patterns](https://rads.stackoverflow.com/amzn/click/com/0596007124). |
718,632 | I've been looking to improve my programming habits and I heard that OO is the way to go.
Also I'd much prefer online tutorials over books. | 2009/04/05 | [
"https://Stackoverflow.com/questions/718632",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/75173/"
] | Here are a few good tutorials from the PHP guys themselves.
* [PHP 101 (part 7): The Bear Necessities](http://devzone.zend.com/node/view/id/638)
* [The OO Evolution of PHP](http://devzone.zend.com/article/1717-The-OO-Evolution-of-PHP)
* [Using Objects to Create an Application](http://devzone.zend.com/article/1240-Using-Objects-to-Create-an-Application) | Although the jury is out on certification, you could do far worse than attend a [Zend course](http://www.zend.com/en/services/certification/php-5-certification/). |
718,632 | I've been looking to improve my programming habits and I heard that OO is the way to go.
Also I'd much prefer online tutorials over books. | 2009/04/05 | [
"https://Stackoverflow.com/questions/718632",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/75173/"
] | Неге is nice book which shows OOP in practice. You can download the sources from website and look what the book is about.
<http://objectorientedphp.com/> | Although the jury is out on certification, you could do far worse than attend a [Zend course](http://www.zend.com/en/services/certification/php-5-certification/). |
718,632 | I've been looking to improve my programming habits and I heard that OO is the way to go.
Also I'd much prefer online tutorials over books. | 2009/04/05 | [
"https://Stackoverflow.com/questions/718632",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/75173/"
] | Here are a few good tutorials from the PHP guys themselves.
* [PHP 101 (part 7): The Bear Necessities](http://devzone.zend.com/node/view/id/638)
* [The OO Evolution of PHP](http://devzone.zend.com/article/1717-The-OO-Evolution-of-PHP)
* [Using Objects to Create an Application](http://devzone.zend.com/article/1240-Using-Objects-to-Create-an-Application) | Неге is nice book which shows OOP in practice. You can download the sources from website and look what the book is about.
<http://objectorientedphp.com/> |
718,632 | I've been looking to improve my programming habits and I heard that OO is the way to go.
Also I'd much prefer online tutorials over books. | 2009/04/05 | [
"https://Stackoverflow.com/questions/718632",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/75173/"
] | * [OO Tips](http://www.ootips.org/)
* [PHP Classes](http://www.phpclasses.org/)
* [OOP in PHP](http://www.devarticles.com/c/a/PHP/Object-Oriented-Programming-in-PHP/)
* and [Google](http://www.google.com/search?q=object%20oriented%20programming%20using%20php&hl=en&safe=off&client=firefox-a&rls=org.mozilla:en-US:official&hs=qGl&start=70&sa=N&cts=1238930053986) of course!
*OO is not a language-depended concept.* | Неге is nice book which shows OOP in practice. You can download the sources from website and look what the book is about.
<http://objectorientedphp.com/> |
718,632 | I've been looking to improve my programming habits and I heard that OO is the way to go.
Also I'd much prefer online tutorials over books. | 2009/04/05 | [
"https://Stackoverflow.com/questions/718632",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/75173/"
] | Learning how to use classes, methods, and attributes is not sufficient for making you a good object oriented programmer. The other (and usually much more difficult) part is understanding how to solve problems in an object-oriented way.
It's a bit like chess: Even if you have memorized the rules perfectly, it does not mean you automatically are a good chess player. You still need to learn a about strategy and gather a lot of experience.
I haven't found a good web tutorial on how to become a good object-oriented programmer. The topic is too large to be covered within just a few web pages. You are probably better off reading a book on the subject. It doesn't even have to be specific to php, most OO pricinples can be applied to many different OO languages.
Once you have learned the basics of OO programming, I'd also recommend reading a book on design patterns such as the classic [Design Patterns](http://www.amazon.co.uk/Design-patterns-elements-reusable-object-oriented/dp/0201633612/ref=sr_1_1?ie=UTF8&s=books&qid=1238931499&sr=1-1) by Gamma et al. or the more casual [Head-First Design patterns](https://rads.stackoverflow.com/amzn/click/com/0596007124). | A great place to start is the [PHP Classes and Objects](http://php.net/zend-engine-2.php) manual page. |
718,632 | I've been looking to improve my programming habits and I heard that OO is the way to go.
Also I'd much prefer online tutorials over books. | 2009/04/05 | [
"https://Stackoverflow.com/questions/718632",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/75173/"
] | Learning how to use classes, methods, and attributes is not sufficient for making you a good object oriented programmer. The other (and usually much more difficult) part is understanding how to solve problems in an object-oriented way.
It's a bit like chess: Even if you have memorized the rules perfectly, it does not mean you automatically are a good chess player. You still need to learn a about strategy and gather a lot of experience.
I haven't found a good web tutorial on how to become a good object-oriented programmer. The topic is too large to be covered within just a few web pages. You are probably better off reading a book on the subject. It doesn't even have to be specific to php, most OO pricinples can be applied to many different OO languages.
Once you have learned the basics of OO programming, I'd also recommend reading a book on design patterns such as the classic [Design Patterns](http://www.amazon.co.uk/Design-patterns-elements-reusable-object-oriented/dp/0201633612/ref=sr_1_1?ie=UTF8&s=books&qid=1238931499&sr=1-1) by Gamma et al. or the more casual [Head-First Design patterns](https://rads.stackoverflow.com/amzn/click/com/0596007124). | Неге is nice book which shows OOP in practice. You can download the sources from website and look what the book is about.
<http://objectorientedphp.com/> |
718,632 | I've been looking to improve my programming habits and I heard that OO is the way to go.
Also I'd much prefer online tutorials over books. | 2009/04/05 | [
"https://Stackoverflow.com/questions/718632",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/75173/"
] | Here are a few good tutorials from the PHP guys themselves.
* [PHP 101 (part 7): The Bear Necessities](http://devzone.zend.com/node/view/id/638)
* [The OO Evolution of PHP](http://devzone.zend.com/article/1717-The-OO-Evolution-of-PHP)
* [Using Objects to Create an Application](http://devzone.zend.com/article/1240-Using-Objects-to-Create-an-Application) | A great place to start is the [PHP Classes and Objects](http://php.net/zend-engine-2.php) manual page. |
25,485,565 | I am looking Magento module that has instant search feature, which is fast. I have more than 150k products on my store.
Any suggestion? | 2014/08/25 | [
"https://Stackoverflow.com/questions/25485565",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/633650/"
] | This is a basic examle for Concurrency. Once you call the .Start() method on a thread object, it starts getting executed independent of the thread that started it. What your programm is doing:
1. Create the thread objects
2. Start tobj1 (the thread is not executed directly, but once the scheduler finds a place to put it)
3. Start tobj2 (the thread is again not executed directly)
The [scheduler](http://en.wikipedia.org/wiki/Scheduling_%28computing%29) is responsible to tell the processor which process and which thread to execute. The order in which the threads are started is of no importance.
As soon as one thread starts, he prints the first line ("Thread X Entered"). The Lock is a synchronization statement. Since both threads sync on the same object instance, they cannot enter the Lock block both ([Mutual Exclusion](http://en.wikipedia.org/wiki/Mutual_exclusion)). The Lock statement only ensures that the process can work in the critical section without the other process working it his critical section. As you see in your right output, a thread can be interrupted although he is in his critical section ("Thread 2 started", "Thread One Entered", "..."). "Thread One", however, is not allowed to his critical section since the other thread did not release the lock yet. | This is in the heart of threads programming. While you have control over which thread you want to start first, the CPU is not obliged to follow your order of events. During the execution of one thread the CPU is guaranteed to follow you order of code execution as per your programming. When it comes to scheduling different threads, the CPU will follow its own logic and sometimes that logic can seem like random behavior. It will allocate processing time to different threads as it sees fit.
I suggest you read up more on threads programming as not fully understanding this concept and appreciating it's potential pitfalls will lead to many days of hair pulling and possible deadlocks :)
Just google: c# threading. You will get plenty of good resources! |
59,667 | I work as software test engineer in a medium sized IT company. My lead usually assigns me task for the day which I try to finish asap. Sometimes when there is no build to test or when all the test execution is done, i have nothing to do for rest of the day. I read in a self-improvement/productivity article that to be more effective always ask more and more work from your boss. Would this be the right thing to do as a professional? | 2015/12/20 | [
"https://workplace.stackexchange.com/questions/59667",
"https://workplace.stackexchange.com",
"https://workplace.stackexchange.com/users/45187/"
] | Yes.
Even better than asking for more work, demonstrate some initiative. Try and think of something you could do to improve some aspect of your job/division/company then take that proposal to your boss.
You know what bosses like even more than employees who get their work done? Employees who don't even have to be told what to do, because they'll create value of their own accord. | Yes, it's a good thing to do once in a while. It shows you're keen. Bear in my mind that it can also have two repercussions.
Firstly it adds more work to your manager, which he/she may or may not be happy about if it's constantly happening. They need to then find or make up more work for you to do.
Secondly you may find yourself lumped with all the more distasteful jobs available and it can become the norm to just assign those and any extra work to you.
But it is still a good idea in moderation. In that situation when I had time on my hands, before asking for more work I would look for other things to do first. So I would doublecheck my work, clean my work area thoroughly, organise my files and other things I may have been putting off. I spent a whole constructive afternoon once just organising my email folders and filing system on my computer. It wasn't wasted time, it made things easier and more efficient for me. |
59,667 | I work as software test engineer in a medium sized IT company. My lead usually assigns me task for the day which I try to finish asap. Sometimes when there is no build to test or when all the test execution is done, i have nothing to do for rest of the day. I read in a self-improvement/productivity article that to be more effective always ask more and more work from your boss. Would this be the right thing to do as a professional? | 2015/12/20 | [
"https://workplace.stackexchange.com/questions/59667",
"https://workplace.stackexchange.com",
"https://workplace.stackexchange.com/users/45187/"
] | Yes.
Even better than asking for more work, demonstrate some initiative. Try and think of something you could do to improve some aspect of your job/division/company then take that proposal to your boss.
You know what bosses like even more than employees who get their work done? Employees who don't even have to be told what to do, because they'll create value of their own accord. | Yes, if you're just starting out. As a habit, no.
If you're new, it makes sense that your lead would have to search a bit to find work that you can do that fits your skills and knowledge. Then they would maybe want to review it before moving on to the next one.
As you gain experience, it is expected that you "dive in" more, understand the projects you're working on and the tasks that are needed to complete them, and those would take more than a few hours. When that happens, you should take more initiative and, while communicating and consulting your lead about the tasks (prioritization, design questions etc.), you would not ask them for a new task every day. |
59,667 | I work as software test engineer in a medium sized IT company. My lead usually assigns me task for the day which I try to finish asap. Sometimes when there is no build to test or when all the test execution is done, i have nothing to do for rest of the day. I read in a self-improvement/productivity article that to be more effective always ask more and more work from your boss. Would this be the right thing to do as a professional? | 2015/12/20 | [
"https://workplace.stackexchange.com/questions/59667",
"https://workplace.stackexchange.com",
"https://workplace.stackexchange.com/users/45187/"
] | Yes.
Even better than asking for more work, demonstrate some initiative. Try and think of something you could do to improve some aspect of your job/division/company then take that proposal to your boss.
You know what bosses like even more than employees who get their work done? Employees who don't even have to be told what to do, because they'll create value of their own accord. | You should ask for more work.
The only exception is if your manager knows you are finished, knows you are looking for more work, and there is no more work, and you asked before, so you know that asking for more work is pointless and only gets on his nerves.
In that case you can search for useful things to do. Always an excellent thing to do is learning things that both improve your knowledge and value to the general world, and your value to the company. In your company's interest you pick something that is of value of the company, in your own interest you pick something that is generally useful out of the things you might learn.
And most people have a huge backlog of things that would have been nice to do, but never had high enough priority, and that you can do. Much better to go to your boss and say "Hey boss, I finished my tasks and have nothing else to do, so I decided to do XYZ, which we always wanted to do and never had the time for, unless you have something more important". |
59,667 | I work as software test engineer in a medium sized IT company. My lead usually assigns me task for the day which I try to finish asap. Sometimes when there is no build to test or when all the test execution is done, i have nothing to do for rest of the day. I read in a self-improvement/productivity article that to be more effective always ask more and more work from your boss. Would this be the right thing to do as a professional? | 2015/12/20 | [
"https://workplace.stackexchange.com/questions/59667",
"https://workplace.stackexchange.com",
"https://workplace.stackexchange.com/users/45187/"
] | Yes.
Even better than asking for more work, demonstrate some initiative. Try and think of something you could do to improve some aspect of your job/division/company then take that proposal to your boss.
You know what bosses like even more than employees who get their work done? Employees who don't even have to be told what to do, because they'll create value of their own accord. | You may work on perfecting the given task. Could we have an extra Unit test? Could we improve the code? Have you tested everything properly, have you documented everything as required? Have you read all documentation you are supposed to know? And is it clear enough what this third party library method you call actually does?
Completing the task quickly but badly may not be the best way to impress. If the manager has allocated that amount of time for the task, maybe he wants the best possible implementation that could be written during this time.
Procedures like code reviews mostly aim to increase the quality of the work, even with understanding that it will take longer to complete it. |
59,667 | I work as software test engineer in a medium sized IT company. My lead usually assigns me task for the day which I try to finish asap. Sometimes when there is no build to test or when all the test execution is done, i have nothing to do for rest of the day. I read in a self-improvement/productivity article that to be more effective always ask more and more work from your boss. Would this be the right thing to do as a professional? | 2015/12/20 | [
"https://workplace.stackexchange.com/questions/59667",
"https://workplace.stackexchange.com",
"https://workplace.stackexchange.com/users/45187/"
] | Yes, it's a good thing to do once in a while. It shows you're keen. Bear in my mind that it can also have two repercussions.
Firstly it adds more work to your manager, which he/she may or may not be happy about if it's constantly happening. They need to then find or make up more work for you to do.
Secondly you may find yourself lumped with all the more distasteful jobs available and it can become the norm to just assign those and any extra work to you.
But it is still a good idea in moderation. In that situation when I had time on my hands, before asking for more work I would look for other things to do first. So I would doublecheck my work, clean my work area thoroughly, organise my files and other things I may have been putting off. I spent a whole constructive afternoon once just organising my email folders and filing system on my computer. It wasn't wasted time, it made things easier and more efficient for me. | You should ask for more work.
The only exception is if your manager knows you are finished, knows you are looking for more work, and there is no more work, and you asked before, so you know that asking for more work is pointless and only gets on his nerves.
In that case you can search for useful things to do. Always an excellent thing to do is learning things that both improve your knowledge and value to the general world, and your value to the company. In your company's interest you pick something that is of value of the company, in your own interest you pick something that is generally useful out of the things you might learn.
And most people have a huge backlog of things that would have been nice to do, but never had high enough priority, and that you can do. Much better to go to your boss and say "Hey boss, I finished my tasks and have nothing else to do, so I decided to do XYZ, which we always wanted to do and never had the time for, unless you have something more important". |
59,667 | I work as software test engineer in a medium sized IT company. My lead usually assigns me task for the day which I try to finish asap. Sometimes when there is no build to test or when all the test execution is done, i have nothing to do for rest of the day. I read in a self-improvement/productivity article that to be more effective always ask more and more work from your boss. Would this be the right thing to do as a professional? | 2015/12/20 | [
"https://workplace.stackexchange.com/questions/59667",
"https://workplace.stackexchange.com",
"https://workplace.stackexchange.com/users/45187/"
] | Yes, it's a good thing to do once in a while. It shows you're keen. Bear in my mind that it can also have two repercussions.
Firstly it adds more work to your manager, which he/she may or may not be happy about if it's constantly happening. They need to then find or make up more work for you to do.
Secondly you may find yourself lumped with all the more distasteful jobs available and it can become the norm to just assign those and any extra work to you.
But it is still a good idea in moderation. In that situation when I had time on my hands, before asking for more work I would look for other things to do first. So I would doublecheck my work, clean my work area thoroughly, organise my files and other things I may have been putting off. I spent a whole constructive afternoon once just organising my email folders and filing system on my computer. It wasn't wasted time, it made things easier and more efficient for me. | You may work on perfecting the given task. Could we have an extra Unit test? Could we improve the code? Have you tested everything properly, have you documented everything as required? Have you read all documentation you are supposed to know? And is it clear enough what this third party library method you call actually does?
Completing the task quickly but badly may not be the best way to impress. If the manager has allocated that amount of time for the task, maybe he wants the best possible implementation that could be written during this time.
Procedures like code reviews mostly aim to increase the quality of the work, even with understanding that it will take longer to complete it. |
59,667 | I work as software test engineer in a medium sized IT company. My lead usually assigns me task for the day which I try to finish asap. Sometimes when there is no build to test or when all the test execution is done, i have nothing to do for rest of the day. I read in a self-improvement/productivity article that to be more effective always ask more and more work from your boss. Would this be the right thing to do as a professional? | 2015/12/20 | [
"https://workplace.stackexchange.com/questions/59667",
"https://workplace.stackexchange.com",
"https://workplace.stackexchange.com/users/45187/"
] | Yes, if you're just starting out. As a habit, no.
If you're new, it makes sense that your lead would have to search a bit to find work that you can do that fits your skills and knowledge. Then they would maybe want to review it before moving on to the next one.
As you gain experience, it is expected that you "dive in" more, understand the projects you're working on and the tasks that are needed to complete them, and those would take more than a few hours. When that happens, you should take more initiative and, while communicating and consulting your lead about the tasks (prioritization, design questions etc.), you would not ask them for a new task every day. | You should ask for more work.
The only exception is if your manager knows you are finished, knows you are looking for more work, and there is no more work, and you asked before, so you know that asking for more work is pointless and only gets on his nerves.
In that case you can search for useful things to do. Always an excellent thing to do is learning things that both improve your knowledge and value to the general world, and your value to the company. In your company's interest you pick something that is of value of the company, in your own interest you pick something that is generally useful out of the things you might learn.
And most people have a huge backlog of things that would have been nice to do, but never had high enough priority, and that you can do. Much better to go to your boss and say "Hey boss, I finished my tasks and have nothing else to do, so I decided to do XYZ, which we always wanted to do and never had the time for, unless you have something more important". |
59,667 | I work as software test engineer in a medium sized IT company. My lead usually assigns me task for the day which I try to finish asap. Sometimes when there is no build to test or when all the test execution is done, i have nothing to do for rest of the day. I read in a self-improvement/productivity article that to be more effective always ask more and more work from your boss. Would this be the right thing to do as a professional? | 2015/12/20 | [
"https://workplace.stackexchange.com/questions/59667",
"https://workplace.stackexchange.com",
"https://workplace.stackexchange.com/users/45187/"
] | Yes, if you're just starting out. As a habit, no.
If you're new, it makes sense that your lead would have to search a bit to find work that you can do that fits your skills and knowledge. Then they would maybe want to review it before moving on to the next one.
As you gain experience, it is expected that you "dive in" more, understand the projects you're working on and the tasks that are needed to complete them, and those would take more than a few hours. When that happens, you should take more initiative and, while communicating and consulting your lead about the tasks (prioritization, design questions etc.), you would not ask them for a new task every day. | You may work on perfecting the given task. Could we have an extra Unit test? Could we improve the code? Have you tested everything properly, have you documented everything as required? Have you read all documentation you are supposed to know? And is it clear enough what this third party library method you call actually does?
Completing the task quickly but badly may not be the best way to impress. If the manager has allocated that amount of time for the task, maybe he wants the best possible implementation that could be written during this time.
Procedures like code reviews mostly aim to increase the quality of the work, even with understanding that it will take longer to complete it. |
59,455 | I came across this interesting [photographic work](https://courroiedetransmission.wordpress.com/2012/08/19/klavdij-sluban-iles-kerguelen/) by an artist who went to [Kerguelen Islands](https://goo.gl/maps/AKHfPwQxa6B2), a windswept rock with a lunar landscape in the South Indian Ocean also known by the cheerful name "Îles de la Désolation".
[Wikivoyage](https://en.wikivoyage.org/wiki/Kerguelen#Get_in) mentions the Marion-Dufresne ferry from Île de la Réunion, and Sluban himself [talks](http://www.institutfrance.si/klavidj-sluban.html) about the sea voyage.
Is this ferry the only way on and off the island ? | 2015/12/02 | [
"https://travel.stackexchange.com/questions/59455",
"https://travel.stackexchange.com",
"https://travel.stackexchange.com/users/9551/"
] | Beautiful photos, they certainly capture the atmosphere there.
There is indeed no airport and the supply vessel, Marion Dufresne is not really a ferry. It transports the personnel and supplies destined for the research facilities on the Crozet, Kerguelen and Saint Paul & Amsterdam islands. The round trip from Reunion Island takes one month when everything goes well. On some trips there are a limited number of berths for visitors. More information at <http://www.taaf.fr/Participation-a-une-rotation-australe-du-Marion-Dufresne>.
>
> *Pour y accéder, un seul moyen de transport : le Marion Dufresne (4 à 6
> jours de navigation pour atteindre les îles australes depuis la
> Réunion).*
>
>
> There's only one way to access the islands: the Marion Dufresne (4 to
> 6 days of navigation to reach the islands from Réunion)
>
>
> | If the [French Wikitravel article on Kerguelen](https://fr.wikivoyage.org/wiki/Archipel_des_Kerguelen) is to be believed, there is no airport on the island:
>
> Aucune infrastructure n'est prévue pour permettre l'atterrissage d'avions, un tel projet pourtant entamé il y a quelques années est aujourd'hui retombé dans l'oubli.
>
>
>
... which translates as:
>
> No infrastructure is present to permit the landing of airplanes; such a project was started some years ago, but has since been forgotten.
>
>
>
The only other reference in the article to other ships visiting the island is in the section on medical evacuation:
>
> Il est à signaler que les cas pathologiques les plus graves nécessitent généralement une évacuation sanitaire, une opération déléguée à des navires présents sur le secteur au moment de la survenue des faits. Le temps de transport vers un lieu médicalisé est donc assez variable.
>
>
> It should be noted that the worst medical cases generally require medical evacuation, which is delegated to ships present in the area when such an operation is deemed necessary. Transport time to a location with medical care is therefore quite variable.
>
>
> |
11,880 | I am looking for a software, a library or an algorithm that can be trained to recognize about a dozen speaker independent voice commands.
The commands will be very distinct phrases of 4-5 words each. They can be chosen to sound very different from each other. Additionally, the commands will be in more than two different languages. The user will be guided to say only the exact phrases and talk slowly, loud and clear in front of the microphone.
I am currently looking for an algorithm that can compare speech spectrograms and give me a matching percentage, but no luck so far. Any ideas?
If it helps, the code can be written for the specific phrases only, and, in worst case, the phrases can be reduced to 3 or 4.
Operating system can be Linux (preferably), Windows or Android. No Internet services. | 2014/10/01 | [
"https://softwarerecs.stackexchange.com/questions/11880",
"https://softwarerecs.stackexchange.com",
"https://softwarerecs.stackexchange.com/users/8044/"
] | [Simon](https://simon.kde.org/) is exactly what you are looking for.
Simon is **not a full speech-to-text engine** like Dragon Naturally Speaking is, but rather you can program Simon to **recognize specific phrases and to perform specific actions**. This works even if the phrases are **spoken by different people**.
Simon runs on all modern Linux distros, and is **very easy to install and configure**. | You need a software application like, [Dragon Naturally Speaking](http://shop.nuance.com/store/nuanceus/Custom/pbpage.resp-dragon-home-basics/&kpid=PLA_Dragon_Premium_DNS_13?kpid=PLA_Dragon_Premium_DNS_13&gclid=CLiFhoHYrcECFZBi7AodP0AAqw). Dragon Naturally Speaking is one of the original voice recognition programs. I remember hearing of them back when this was a novelty.
Here is their pitch for the professional version:
>
> Command greater productivity.
>
>
> Perfect for students, teachers, professors, self-employed workers,
> consultants, professionals, writers/bloggers, and people who spend a
> lot of time on the computer. Dictate up to three times faster than
> typing; your words appear on the screen almost instantly. Speak
> naturally and Dragon recognizes what you say with up to 99% accuracy.
> Dictate documents, spreadsheets and presentations with no spelling
> mistakes. Capture notes using a digital voice recorder or compatible
> iOS® and Android™ devices and Dragon will transcribe the audio for
> you. Take advantage of wideband Bluetooth® support for superior
> wireless accuracy. Application support with Full Text Control using
> Excel® 2010 and 2013 (32-bit and 64-bit). Application support with
> Menu Tracking, and English Natural Language Commands in Microsoft
> PowerPoint® 2010 and 2013. Mobile dictation - allows transcription of
> recordings spoken by one person. Ability to import/export custom word
> lists and user profiles. Easily create commands to insert frequently
> used text and/or graphics by voice.
>
>
> |
11,880 | I am looking for a software, a library or an algorithm that can be trained to recognize about a dozen speaker independent voice commands.
The commands will be very distinct phrases of 4-5 words each. They can be chosen to sound very different from each other. Additionally, the commands will be in more than two different languages. The user will be guided to say only the exact phrases and talk slowly, loud and clear in front of the microphone.
I am currently looking for an algorithm that can compare speech spectrograms and give me a matching percentage, but no luck so far. Any ideas?
If it helps, the code can be written for the specific phrases only, and, in worst case, the phrases can be reduced to 3 or 4.
Operating system can be Linux (preferably), Windows or Android. No Internet services. | 2014/10/01 | [
"https://softwarerecs.stackexchange.com/questions/11880",
"https://softwarerecs.stackexchange.com",
"https://softwarerecs.stackexchange.com/users/8044/"
] | **[CMU PocketSphinx](http://cmusphinx.sourceforge.net/wiki/download)** is specifically designed to work in cases where a small set of voice commands are employed. As it uses a word-dependent phone dictionary, this would allow you to easily map different pronunciations to word actions.
It is possible to [further train the system when additional accuracy is required](http://cmusphinx.sourceforge.net/wiki/tutorialam).
Your requirement of an algorithm giving you a "matching percentage" is best described by PocketSphinx with [confidence values](https://stackoverflow.com/questions/26577739/pocketsphinx-getting-the-probabilities-of-the-words), which are returned on a per-word basis. | You need a software application like, [Dragon Naturally Speaking](http://shop.nuance.com/store/nuanceus/Custom/pbpage.resp-dragon-home-basics/&kpid=PLA_Dragon_Premium_DNS_13?kpid=PLA_Dragon_Premium_DNS_13&gclid=CLiFhoHYrcECFZBi7AodP0AAqw). Dragon Naturally Speaking is one of the original voice recognition programs. I remember hearing of them back when this was a novelty.
Here is their pitch for the professional version:
>
> Command greater productivity.
>
>
> Perfect for students, teachers, professors, self-employed workers,
> consultants, professionals, writers/bloggers, and people who spend a
> lot of time on the computer. Dictate up to three times faster than
> typing; your words appear on the screen almost instantly. Speak
> naturally and Dragon recognizes what you say with up to 99% accuracy.
> Dictate documents, spreadsheets and presentations with no spelling
> mistakes. Capture notes using a digital voice recorder or compatible
> iOS® and Android™ devices and Dragon will transcribe the audio for
> you. Take advantage of wideband Bluetooth® support for superior
> wireless accuracy. Application support with Full Text Control using
> Excel® 2010 and 2013 (32-bit and 64-bit). Application support with
> Menu Tracking, and English Natural Language Commands in Microsoft
> PowerPoint® 2010 and 2013. Mobile dictation - allows transcription of
> recordings spoken by one person. Ability to import/export custom word
> lists and user profiles. Easily create commands to insert frequently
> used text and/or graphics by voice.
>
>
> |
60,162,448 | I have uploaded the new build yesterday , after accepting missing compliance option status of build is 'Testing' but still invitation is not send to internal testers and not even showing any update in testflight app for that build . I have added 4 testers for this build . Please refer screenshot for the same .[](https://i.stack.imgur.com/sct25.png) | 2020/02/11 | [
"https://Stackoverflow.com/questions/60162448",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/11018922/"
] | I got this from <https://twitter.com/hashtag/testflight>
>
> We can fix TestFlightApp new build issue by adding the "App Uses Non-Exempt Encryption" key in Info.plist (in my case set NO)and republishing
>
>
> <https://developer.apple.com/documentation/security/complying_with_encryption_export_regulations>
>
>
>
Source: <https://twitter.com/Reddybashashaik/status/1227231610434490368>
Add ITSAppUsesNonExemptEncryption to your Info.plist
---
I also noted that it seems like it works to invite users by
* being in App Store Connect,
* clicking on your app,
* choose *TestFlight* from the menu,
* then click on your latest build number (possibly folding it out from under *Version X.X.X*),
* and then invite users manually under the headline *Individual Tester*. | Remove all account from testing mail address who's not getting an update and add again they will get a new invite again.
They have to accept the request and they need to use the Testflight app in that they will enter a code which they will get in the mail. |
60,162,448 | I have uploaded the new build yesterday , after accepting missing compliance option status of build is 'Testing' but still invitation is not send to internal testers and not even showing any update in testflight app for that build . I have added 4 testers for this build . Please refer screenshot for the same .[](https://i.stack.imgur.com/sct25.png) | 2020/02/11 | [
"https://Stackoverflow.com/questions/60162448",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/11018922/"
] | To fix this issue you have to add new key *ITSAppUsesNonExemptEncryption* into your info.plist.
See <https://forums.developer.apple.com/thread/128878?start=105> for details. | Remove all account from testing mail address who's not getting an update and add again they will get a new invite again.
They have to accept the request and they need to use the Testflight app in that they will enter a code which they will get in the mail. |
60,162,448 | I have uploaded the new build yesterday , after accepting missing compliance option status of build is 'Testing' but still invitation is not send to internal testers and not even showing any update in testflight app for that build . I have added 4 testers for this build . Please refer screenshot for the same .[](https://i.stack.imgur.com/sct25.png) | 2020/02/11 | [
"https://Stackoverflow.com/questions/60162448",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/11018922/"
] | I got this from <https://twitter.com/hashtag/testflight>
>
> We can fix TestFlightApp new build issue by adding the "App Uses Non-Exempt Encryption" key in Info.plist (in my case set NO)and republishing
>
>
> <https://developer.apple.com/documentation/security/complying_with_encryption_export_regulations>
>
>
>
Source: <https://twitter.com/Reddybashashaik/status/1227231610434490368>
Add ITSAppUsesNonExemptEncryption to your Info.plist
---
I also noted that it seems like it works to invite users by
* being in App Store Connect,
* clicking on your app,
* choose *TestFlight* from the menu,
* then click on your latest build number (possibly folding it out from under *Version X.X.X*),
* and then invite users manually under the headline *Individual Tester*. | The invitation column for given build number in empty. That means you have not invited any testers to the new build. Open that build and add users. I think you have to add testers for each build. I faced similar problem but when I added testers to new build all my testers got invitation. |
60,162,448 | I have uploaded the new build yesterday , after accepting missing compliance option status of build is 'Testing' but still invitation is not send to internal testers and not even showing any update in testflight app for that build . I have added 4 testers for this build . Please refer screenshot for the same .[](https://i.stack.imgur.com/sct25.png) | 2020/02/11 | [
"https://Stackoverflow.com/questions/60162448",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/11018922/"
] | To fix this issue you have to add new key *ITSAppUsesNonExemptEncryption* into your info.plist.
See <https://forums.developer.apple.com/thread/128878?start=105> for details. | The invitation column for given build number in empty. That means you have not invited any testers to the new build. Open that build and add users. I think you have to add testers for each build. I faced similar problem but when I added testers to new build all my testers got invitation. |
60,162,448 | I have uploaded the new build yesterday , after accepting missing compliance option status of build is 'Testing' but still invitation is not send to internal testers and not even showing any update in testflight app for that build . I have added 4 testers for this build . Please refer screenshot for the same .[](https://i.stack.imgur.com/sct25.png) | 2020/02/11 | [
"https://Stackoverflow.com/questions/60162448",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/11018922/"
] | I got this from <https://twitter.com/hashtag/testflight>
>
> We can fix TestFlightApp new build issue by adding the "App Uses Non-Exempt Encryption" key in Info.plist (in my case set NO)and republishing
>
>
> <https://developer.apple.com/documentation/security/complying_with_encryption_export_regulations>
>
>
>
Source: <https://twitter.com/Reddybashashaik/status/1227231610434490368>
Add ITSAppUsesNonExemptEncryption to your Info.plist
---
I also noted that it seems like it works to invite users by
* being in App Store Connect,
* clicking on your app,
* choose *TestFlight* from the menu,
* then click on your latest build number (possibly folding it out from under *Version X.X.X*),
* and then invite users manually under the headline *Individual Tester*. | To fix this issue you have to add new key *ITSAppUsesNonExemptEncryption* into your info.plist.
See <https://forums.developer.apple.com/thread/128878?start=105> for details. |
60,162,448 | I have uploaded the new build yesterday , after accepting missing compliance option status of build is 'Testing' but still invitation is not send to internal testers and not even showing any update in testflight app for that build . I have added 4 testers for this build . Please refer screenshot for the same .[](https://i.stack.imgur.com/sct25.png) | 2020/02/11 | [
"https://Stackoverflow.com/questions/60162448",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/11018922/"
] | I got this from <https://twitter.com/hashtag/testflight>
>
> We can fix TestFlightApp new build issue by adding the "App Uses Non-Exempt Encryption" key in Info.plist (in my case set NO)and republishing
>
>
> <https://developer.apple.com/documentation/security/complying_with_encryption_export_regulations>
>
>
>
Source: <https://twitter.com/Reddybashashaik/status/1227231610434490368>
Add ITSAppUsesNonExemptEncryption to your Info.plist
---
I also noted that it seems like it works to invite users by
* being in App Store Connect,
* clicking on your app,
* choose *TestFlight* from the menu,
* then click on your latest build number (possibly folding it out from under *Version X.X.X*),
* and then invite users manually under the headline *Individual Tester*. | Was uploading a few versions successfully to appstore connect for testflight, the new version appears in appstore connect but not on client testflight apps.
Adding ITSAppUsesNonExemptEncryption in info.plist set to NO and reuploading another version solved the issue for me. |
60,162,448 | I have uploaded the new build yesterday , after accepting missing compliance option status of build is 'Testing' but still invitation is not send to internal testers and not even showing any update in testflight app for that build . I have added 4 testers for this build . Please refer screenshot for the same .[](https://i.stack.imgur.com/sct25.png) | 2020/02/11 | [
"https://Stackoverflow.com/questions/60162448",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/11018922/"
] | To fix this issue you have to add new key *ITSAppUsesNonExemptEncryption* into your info.plist.
See <https://forums.developer.apple.com/thread/128878?start=105> for details. | Was uploading a few versions successfully to appstore connect for testflight, the new version appears in appstore connect but not on client testflight apps.
Adding ITSAppUsesNonExemptEncryption in info.plist set to NO and reuploading another version solved the issue for me. |
33,712 | For precision I'm excluding artificial meteoroids and satellite debris (which is discussed in [another question](https://space.stackexchange.com/questions/4858)) of all kinds. I'm also considering collisions large enough to produce a noticeable impact or scar (not truly microscopic dust that can only be detected from wear of the surfaces). Say something carrying at least 1J of kinetic energy. | 2019/01/19 | [
"https://space.stackexchange.com/questions/33712",
"https://space.stackexchange.com",
"https://space.stackexchange.com/users/23003/"
] | Hypervelocity impacts on the space shuttle Orbiters were analyzed over the years to determine their origin.
>
> After the post-flight inspection is completed, JSC
> personnel analyze samples extracted from the impact
> sites using a scanning electron microscope (SEM) equipped
> with energy dispersive X-ray spectrometers (EDXA). Such techniques
> allow engineers to determine whether the impactor was a naturally
> occurring meteoroid or man-made orbital debris.
>
>
>
The paper [ANALYSIS OF THE NASA SHUTTLE HYPERVELOCITY IMPACT DATABASE](https://apps.dtic.mil/dtic/tr/fulltext/u2/a418233.pdf) breaks down the source of the impacts for various regions of the Orbiter.
The majority of the hits are from debris, but some are attributed to meteoroids. Here's an example, a chart showing the results from the Reinforced Carbon-Carbon areas of the Orbiters (mostly the wing leading edges and nosecap).
[](https://i.stack.imgur.com/55w09.png) | [A History of Micrometeoroid and Orbital Debris Impacts On The Space Shuttle](http://adsbit.harvard.edu//full/2001ESASP.473..191H/0000193.000.html) lists the "top 20" strikes on space shuttle windows and radiators from 1992 to 2000; most of them are from debris but 4 appear to be from meteoroids. The biggest meteoroid hit appears to be a 5mm hole in a radiator from an 0.7mm meteoroid. |
33,712 | For precision I'm excluding artificial meteoroids and satellite debris (which is discussed in [another question](https://space.stackexchange.com/questions/4858)) of all kinds. I'm also considering collisions large enough to produce a noticeable impact or scar (not truly microscopic dust that can only be detected from wear of the surfaces). Say something carrying at least 1J of kinetic energy. | 2019/01/19 | [
"https://space.stackexchange.com/questions/33712",
"https://space.stackexchange.com",
"https://space.stackexchange.com/users/23003/"
] | Hypervelocity impacts on the space shuttle Orbiters were analyzed over the years to determine their origin.
>
> After the post-flight inspection is completed, JSC
> personnel analyze samples extracted from the impact
> sites using a scanning electron microscope (SEM) equipped
> with energy dispersive X-ray spectrometers (EDXA). Such techniques
> allow engineers to determine whether the impactor was a naturally
> occurring meteoroid or man-made orbital debris.
>
>
>
The paper [ANALYSIS OF THE NASA SHUTTLE HYPERVELOCITY IMPACT DATABASE](https://apps.dtic.mil/dtic/tr/fulltext/u2/a418233.pdf) breaks down the source of the impacts for various regions of the Orbiter.
The majority of the hits are from debris, but some are attributed to meteoroids. Here's an example, a chart showing the results from the Reinforced Carbon-Carbon areas of the Orbiters (mostly the wing leading edges and nosecap).
[](https://i.stack.imgur.com/55w09.png) | [](https://i.stack.imgur.com/VdAMp.jpg)
Source: <https://www.nasa.gov/feature/goddard/2017/camera-on-nasas-lunar-orbiter-survived-2014-meteoroid-hit>
The above image is from one of the Narrow Angle Cameras on NASA’s Lunar Reconnaissance Orbiter. The very top of the image is clear. The rest shows jagged artifacts. Unlike the digital cameras one can buy in a store, the Narrow Angle Cameras are pushbroom sensors. The scan a line of pixels at a time instead of taking a 2D image. Because a scanned line is orthogonal to the satellite's motion, the next line will be over a slightly different spot, and so on, building an image over time.
The oldest lines in the above image are at the top. The top portion of the image is clear -- but then something happened. Per [NASA](https://www.nasa.gov/feature/goddard/2017/camera-on-nasas-lunar-orbiter-survived-2014-meteoroid-hit), that something was most likely a micrometeoroid, probably a 0.8 mm coarse grain of sand moving at 7 km/s relative to the spacecraft. If NASA is correct, that coarse grain of sand imparted about [18 joules](https://www.wolframalpha.com/input/?i=0.5*4%2F3*pi*(0.8+mm%2F2)%5E3*(2.7+g%2Fcm%5E3)*(7+km%2Fs)%5E2) of energy to the camera.
A relative velocity of 7 km/s is not that high and a joule is not that much energy. In low Earth orbit, relative velocities between a spacecraft and a meteoroid can be ten times that 7 km/s. At that speed, even a very fine grain of sand would impart one joule of energy.
In addition to the impact described above, NASA has brought several items that were in space back to Earth and looked at them for impacts. Two of the answers describe impacts with the Shuttle. In addition to the Shuttle, NASA has retrieved the [Wide Field and Planetary Camera 2](https://space.stackexchange.com/a/4861/2752) and [solar arrays](https://www.sciencedirect.com/science/article/pii/S0734743X99000834) from Hubble and the [Long Duration Exposure Facility](https://en.wikipedia.org/wiki/Long_Duration_Exposure_Facility). All exhibited multiple impacts, some of which were from micrometeoroids, and some of those were large enough to have easily tipped the one joule threshold raised in the question.
And that's just what is known. There are unknown unknowns as well; a number of satellites have prematurely gone permanently offline for no known reason. Some fraction of those were almost certainly due to micrometeoroid damage. |
33,712 | For precision I'm excluding artificial meteoroids and satellite debris (which is discussed in [another question](https://space.stackexchange.com/questions/4858)) of all kinds. I'm also considering collisions large enough to produce a noticeable impact or scar (not truly microscopic dust that can only be detected from wear of the surfaces). Say something carrying at least 1J of kinetic energy. | 2019/01/19 | [
"https://space.stackexchange.com/questions/33712",
"https://space.stackexchange.com",
"https://space.stackexchange.com/users/23003/"
] | [](https://i.stack.imgur.com/VdAMp.jpg)
Source: <https://www.nasa.gov/feature/goddard/2017/camera-on-nasas-lunar-orbiter-survived-2014-meteoroid-hit>
The above image is from one of the Narrow Angle Cameras on NASA’s Lunar Reconnaissance Orbiter. The very top of the image is clear. The rest shows jagged artifacts. Unlike the digital cameras one can buy in a store, the Narrow Angle Cameras are pushbroom sensors. The scan a line of pixels at a time instead of taking a 2D image. Because a scanned line is orthogonal to the satellite's motion, the next line will be over a slightly different spot, and so on, building an image over time.
The oldest lines in the above image are at the top. The top portion of the image is clear -- but then something happened. Per [NASA](https://www.nasa.gov/feature/goddard/2017/camera-on-nasas-lunar-orbiter-survived-2014-meteoroid-hit), that something was most likely a micrometeoroid, probably a 0.8 mm coarse grain of sand moving at 7 km/s relative to the spacecraft. If NASA is correct, that coarse grain of sand imparted about [18 joules](https://www.wolframalpha.com/input/?i=0.5*4%2F3*pi*(0.8+mm%2F2)%5E3*(2.7+g%2Fcm%5E3)*(7+km%2Fs)%5E2) of energy to the camera.
A relative velocity of 7 km/s is not that high and a joule is not that much energy. In low Earth orbit, relative velocities between a spacecraft and a meteoroid can be ten times that 7 km/s. At that speed, even a very fine grain of sand would impart one joule of energy.
In addition to the impact described above, NASA has brought several items that were in space back to Earth and looked at them for impacts. Two of the answers describe impacts with the Shuttle. In addition to the Shuttle, NASA has retrieved the [Wide Field and Planetary Camera 2](https://space.stackexchange.com/a/4861/2752) and [solar arrays](https://www.sciencedirect.com/science/article/pii/S0734743X99000834) from Hubble and the [Long Duration Exposure Facility](https://en.wikipedia.org/wiki/Long_Duration_Exposure_Facility). All exhibited multiple impacts, some of which were from micrometeoroids, and some of those were large enough to have easily tipped the one joule threshold raised in the question.
And that's just what is known. There are unknown unknowns as well; a number of satellites have prematurely gone permanently offline for no known reason. Some fraction of those were almost certainly due to micrometeoroid damage. | [A History of Micrometeoroid and Orbital Debris Impacts On The Space Shuttle](http://adsbit.harvard.edu//full/2001ESASP.473..191H/0000193.000.html) lists the "top 20" strikes on space shuttle windows and radiators from 1992 to 2000; most of them are from debris but 4 appear to be from meteoroids. The biggest meteoroid hit appears to be a 5mm hole in a radiator from an 0.7mm meteoroid. |
5,589,047 | Hello I have a question recently I seen more and more sites using #/pagename instead of going to /pagename which is useful because it does not reload the page.
How can I do the same thing with jQuery? <http://mysite.com/id#/1> <-- would load user with id 1 if you would change that 1 to say 4564 <http://mysite.com/id#/4564> the page would load user data fro 4564 with out refreshing the page it self.
Thanks in advance | 2011/04/08 | [
"https://Stackoverflow.com/questions/5589047",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/692114/"
] | You are actually seeing two things:
1. The request for content is be done asynchronously (AJAX). To accomplish this look at jQuery.Ajax. <http://api.jquery.com/jQuery.ajax/>
2. There is also a 'hash trick' to enable back button support. Typically, a standard Ajax call does not play well with the back button. For this look into the BBQ jQuery library. <http://benalman.com/projects/jquery-bbq-plugin/>
Hope this helps.
Bob | YOU are looking for the [jQuery history plugin](http://tkyk.github.com/jquery-history-plugin/). I've had great success with it, and there are triggers for when the hash changes so you can do whatever you want: load content with AJAX, or load a different slide, etc. |
5,589,047 | Hello I have a question recently I seen more and more sites using #/pagename instead of going to /pagename which is useful because it does not reload the page.
How can I do the same thing with jQuery? <http://mysite.com/id#/1> <-- would load user with id 1 if you would change that 1 to say 4564 <http://mysite.com/id#/4564> the page would load user data fro 4564 with out refreshing the page it self.
Thanks in advance | 2011/04/08 | [
"https://Stackoverflow.com/questions/5589047",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/692114/"
] | You are actually seeing two things:
1. The request for content is be done asynchronously (AJAX). To accomplish this look at jQuery.Ajax. <http://api.jquery.com/jQuery.ajax/>
2. There is also a 'hash trick' to enable back button support. Typically, a standard Ajax call does not play well with the back button. For this look into the BBQ jQuery library. <http://benalman.com/projects/jquery-bbq-plugin/>
Hope this helps.
Bob | I would recommend you look at [sammy](http://sammyjs.org/).
It's a very light javascript framework intended to implement a thin-server model like this where the rendering occurs on the client's computer in javascript instead of served pages from a remote server. This is what allows many sites to avoid doing full reloads of a page every time a user performs an action. |
223,014 | The purring sound of the Enterprise warp core is iconic (for example <https://news.avclub.com/read-this-behind-the-scenes-of-sci-fi-s-most-soothing-1798247701>). Is there an in-universe explanation for the components or processes specifically responsible for this sound?
I'm asking specifically about the throbbing of the warp core, not the engines.
This YouTube video lets you hear the throbbing sound well:
.
It's interesting that some "ambient" videos on YouTube don't present the throbbing sound as distinctly. Which makes me wonder why the film makers sometimes included it and sometimes didn't. Either it's accidental, or the throb is present sometimes but not others for a reason. I'm wondering what that reason might be.
It's possible the throbbing sound has nothing to do with the warp core and is due to some other part of the engine room. But in scenes where the rings of light surrounding the core flash in a way to emulate motion, the flashing seems to follow the same period as the throbbing sound.
This video shows the synchrony between the flashing tubes and the throbbing sound (although the throb sound is very subtle): | 2019/11/13 | [
"https://scifi.stackexchange.com/questions/223014",
"https://scifi.stackexchange.com",
"https://scifi.stackexchange.com/users/69587/"
] | According to the EU novel *[Captain's Glory](https://en.wikipedia.org/wiki/Captain%27s_Glory)* (written by William Shatner), the sound you're hearing is **the sounds of matter-antimatter collision, contained within a forcefield.**
>
> At once he heard **the thrum of the matter-antimatter reactor power up** as the vessel’s shields went from standby navigational mode to battle strength.
>
>
>
The EU novel [*The Shocks of Adversity*](https://memory-alpha.fandom.com/wiki/The_Shocks_of_Adversity) suggest that mixed in with that is **the sound of the warp plasma relays relaying warp plasma.**
>
> With the press of a single button, the low steady thrum of the giant
> matter/antimatter reactor was joined by two higher alternating notes,
> creating a steady rhythm that, judging from the smile Scotty wore as
> he turned from the situation console, was music to his ears. “Isn’t
> that the most beautiful sound ye ever heard, sir?”
>
>
> Kirk shared the engineer’s smile. “Definitely among the top three,” he
> agreed. **The warp plasma relays had been restored and realigned, and
> the mellifluous sounds emitting from the engines confirmed this.**
> “Anything else left outstanding, Scotty?”
>
>
> | The pulsating thrum of the engine could be a [beat](http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/beat.html), that is, the sound resulting from the alternation of constructive and destructive interference of sound waves. But what generates the sound waves to begin with, I do not know. You can hear a beat demonstrated on this brief [YouTube film](https://www.youtube.com/watch?v=V8W4Djz6jnY). |
63,494 | Here's an image to help (the top is the original image, the bottom is after moving the white object to the front):
[](https://i.stack.imgur.com/qS5Ub.png)
What I need is an object that is all of the white in the image. The problem is that the white space is created by stacking blue objects on top of white, so I can't just remove all the blue objects from the .svg file. How can I create objects of the visible white areas?
In the example image, that would mean that instead of white and blue stacked on top of each other, it would be a flat image - blue objects with white objects around them. If you move blue or white, there would be nothing behind it. | 2015/11/20 | [
"https://graphicdesign.stackexchange.com/questions/63494",
"https://graphicdesign.stackexchange.com",
"https://graphicdesign.stackexchange.com/users/54516/"
] | * Select all blue paths;
* Go to Path > Union; this will join them in one big path;
* Select both the white path underneath and the blue shape;
* Go to Path > Difference; this will "cut out" the blue shape out of the white. | A totally different approach which works also (even if it's a bit odd) is to take a screenshot, import it into a new Inkscape file (File -> Import) and then do Trace Bitmap (it's in the Path menu).
This creates a vector object on top of the selected bitmap.
I usually prefer the "vector" approach (as explained in other answers), but sometimes the Bitmap Trace is a kind of "quick and dirty" solution that works well.
More info on Bitmap Tracing in [Tavmjong's manual chapter 20](http://tavmjong.free.fr/INKSCAPE/MANUAL/html/Trace.html). |
4,789,075 | **original question**
when should i use multi-tier web application instead of single tier web application?
**update to my question**
i accepted the following definition to differentiale **"Tier"** and **"Layer"**
**Layers** Refer to specific layers of abstraction with in an application (software) where as **tiers** Refer to the physical residence of those layers (hardware)
App.Layer == "Software"-----logical
App.Tier == "Hardware"------physical
**Layers:**
1) presentation layer
2) business layer
3) data access layer
4) data layer
5) external system access layer
**Tiers:**
1) Presentation tier (webserver)
2) Data tier (database server) | 2011/01/25 | [
"https://Stackoverflow.com/questions/4789075",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/521066/"
] | Let's start by asking, will the application hold data? If it does, is the data going to be read by multiple users concurrently? How often? Based on the answer to these questions (and many other) you might want to decide whether a database is the way to go.
As far as layers (UI, Data Access, Business Logic, etc) is concerned, it trully depends on a project by project basis. Are you developing a web app for proof of concept? Are you expecting it to maintain it? Do you trust all the developers in your team? But my rule of thumb is to alway use layers unless i'm throwing something together really quick to either prove something or know it will never be maintained and I need to do it fast.
If you decide to use a framework such as MVC, MVP, MVVM, etc then by default you're dividing your app into layers.
Keep in mind that these divisions help you isolate certain aspects of your app, which in turn allow you to easily work with TDD, separation of concerns, maintainabilty, etc.
In conclusion, you have to look at your requirements, goals, team members, and short and long term objectives and decide. There is no white or black answer here | >
> when should i use multi-tier web application (Tier == "Hardware"------physical)
>
>
>
Scalability. |
204,687 | I own two starbound characters: one Avian and one Novakid. I need to know how to make a new world for every character. The latter of the two is my first character, and he already exhausted the resources on every planet in the system. I need to know how to generate a new world for my avian, and, if possible, every character after him. | 2015/02/08 | [
"https://gaming.stackexchange.com/questions/204687",
"https://gaming.stackexchange.com",
"https://gaming.stackexchange.com/users/101691/"
] | There's no way to generate a new universe, as each character on your PC will share the same planets. This means any buildings you create can be visited by any character, not just the one that built it. You could also place chests full of things for your other characters to pick up and use for themselves.
Given that there are millions, if not billions, of different planets, all you need to is travel to one you haven't been to before. Every system has a moon where you can collect more than enough fuel to travel anywhere in the universe. | Since all the characters on your pc share the same universe, stuff you leave on the planet will be available for all your characters going there.
So if your first character exhausted the resources of the base planet, you could go haverst some in another system and then bring them back to the base planet and leave them there (in a chest, for instance) so that your second character can come and get them. This would allow your second character to repair the ship and travel to a different location and realy start over there. |
204,687 | I own two starbound characters: one Avian and one Novakid. I need to know how to make a new world for every character. The latter of the two is my first character, and he already exhausted the resources on every planet in the system. I need to know how to generate a new world for my avian, and, if possible, every character after him. | 2015/02/08 | [
"https://gaming.stackexchange.com/questions/204687",
"https://gaming.stackexchange.com",
"https://gaming.stackexchange.com/users/101691/"
] | There's no way to make a new universe for each character *in the game*, but there is a workaround you can use. Amongst the folders where Starbound is installed on your computer, you can find a folder called "universe" and a folder called "player." These folders do exactly what it says on the tin: one saves all your universe data, like all the planets you've visited, and the other stores the data for all of your characters, including also their ships and inventories (but, obviously, not any structures or storage they have on a planet -- that's all in the "universe" folder). Because these folders are separate, you could, for example, delete your "universe" folder, and still keep your characters. If you did this and then launched Starbound it would create a brand-new random universe to replace the delted one, and you'd be able to explore it with your existing characters, and whatever items they had on their ships.
Of course you don't have to delete your current universe. You could move its folder somewhere else, or re-name it, and it'd have the same effect -- the game wouldn't recognize it, and would create a new universe in its place. And later you could restore it to its original name/location and get your old universe back.
By using this method you *can* have a separate universe for each character. Just switch the universes manually, by swapping around different "universe" folders before you launch the game. It's a bit annoying, but totally doable. Incidentally, given how easy it is to do, I am guessing (though this *is* just a guess) that such a feature will eventually be added into the game -- things seem to be set up for it. Starbound is still in development, after all. | There's no way to generate a new universe, as each character on your PC will share the same planets. This means any buildings you create can be visited by any character, not just the one that built it. You could also place chests full of things for your other characters to pick up and use for themselves.
Given that there are millions, if not billions, of different planets, all you need to is travel to one you haven't been to before. Every system has a moon where you can collect more than enough fuel to travel anywhere in the universe. |
204,687 | I own two starbound characters: one Avian and one Novakid. I need to know how to make a new world for every character. The latter of the two is my first character, and he already exhausted the resources on every planet in the system. I need to know how to generate a new world for my avian, and, if possible, every character after him. | 2015/02/08 | [
"https://gaming.stackexchange.com/questions/204687",
"https://gaming.stackexchange.com",
"https://gaming.stackexchange.com/users/101691/"
] | There's no way to make a new universe for each character *in the game*, but there is a workaround you can use. Amongst the folders where Starbound is installed on your computer, you can find a folder called "universe" and a folder called "player." These folders do exactly what it says on the tin: one saves all your universe data, like all the planets you've visited, and the other stores the data for all of your characters, including also their ships and inventories (but, obviously, not any structures or storage they have on a planet -- that's all in the "universe" folder). Because these folders are separate, you could, for example, delete your "universe" folder, and still keep your characters. If you did this and then launched Starbound it would create a brand-new random universe to replace the delted one, and you'd be able to explore it with your existing characters, and whatever items they had on their ships.
Of course you don't have to delete your current universe. You could move its folder somewhere else, or re-name it, and it'd have the same effect -- the game wouldn't recognize it, and would create a new universe in its place. And later you could restore it to its original name/location and get your old universe back.
By using this method you *can* have a separate universe for each character. Just switch the universes manually, by swapping around different "universe" folders before you launch the game. It's a bit annoying, but totally doable. Incidentally, given how easy it is to do, I am guessing (though this *is* just a guess) that such a feature will eventually be added into the game -- things seem to be set up for it. Starbound is still in development, after all. | Since all the characters on your pc share the same universe, stuff you leave on the planet will be available for all your characters going there.
So if your first character exhausted the resources of the base planet, you could go haverst some in another system and then bring them back to the base planet and leave them there (in a chest, for instance) so that your second character can come and get them. This would allow your second character to repair the ship and travel to a different location and realy start over there. |
1,184 | For a school project, I'm trying to make an automated flight planner, considering mainly the differences in flight paths according to wind.
Now I've heard that flying with/against the wind affects airspeed. But I really don't know any specific(even empirical) laws on determining by how much it does so.
What's more, I've also heard about gas savings through these effects. That I would have pretty much no idea of how to calculate but that's less important.
Basically if anyone can point me in the right direction to figure out how to figure out solid speed gains, I'd be grateful, even moreso if I can find out the theoretical origins of such laws.
(The only thing I found that I think is close to what I want is [this](http://en.wikipedia.org/wiki/E6B), but I have no clue what the laws derive from) | 2010/11/21 | [
"https://physics.stackexchange.com/questions/1184",
"https://physics.stackexchange.com",
"https://physics.stackexchange.com/users/579/"
] | Well, the formulae in the Wikipedia page you reference are simple consequences of this model:
* Your aircraft instruments measure speed relative to the surrounding air (air speed)
* The surrounding air moves with respect to the ground (wind speed)
* The speed of the aircraft vs the ground will be the vector sum of both these speeds.
To first order (and I'm pretty sure that should suffice for your school project) the resulting fuel savings ensue through the fact that you only need to expend fuel to maintain air speed - basically, if the wind carries the surrounding air in your direction of travel, you have to travel shorter distances "through the air".
The mathematics underlying this consists of vector addition in the simple case and maybe addition of vector fields/line integrals in these vector fields for more complex cases. | +1 on the notion that ground speed is the straightforward vector addition of air speed and wind speed.
Manual flight computers such as the classic Dalton E6B allow you to do this vector math graphically. From a starting point in the middle of your plastic plate you draw a line in the direction of the wind speed, with a length proportional to the wind speed. From there you draw a line in the direction of your air speed (which is your aircraft's heading), with a length proportional to your air speed. Then the vector from start to finish is your ground speed and your ground track (direction you are travelling over the ground).
Concerning the extra fuel you need to burn to fly into a headwind or the fuel you save by flying with a tailwind, a most practical consideration to note is that if you fly from pt. A to pt. B into a headwind, and then turn around and fly from B back to A with a tailwind of the same strength, you lose more flying into the headwind than you gain from flying with the tailwind. |
1,184 | For a school project, I'm trying to make an automated flight planner, considering mainly the differences in flight paths according to wind.
Now I've heard that flying with/against the wind affects airspeed. But I really don't know any specific(even empirical) laws on determining by how much it does so.
What's more, I've also heard about gas savings through these effects. That I would have pretty much no idea of how to calculate but that's less important.
Basically if anyone can point me in the right direction to figure out how to figure out solid speed gains, I'd be grateful, even moreso if I can find out the theoretical origins of such laws.
(The only thing I found that I think is close to what I want is [this](http://en.wikipedia.org/wiki/E6B), but I have no clue what the laws derive from) | 2010/11/21 | [
"https://physics.stackexchange.com/questions/1184",
"https://physics.stackexchange.com",
"https://physics.stackexchange.com/users/579/"
] | Well, the formulae in the Wikipedia page you reference are simple consequences of this model:
* Your aircraft instruments measure speed relative to the surrounding air (air speed)
* The surrounding air moves with respect to the ground (wind speed)
* The speed of the aircraft vs the ground will be the vector sum of both these speeds.
To first order (and I'm pretty sure that should suffice for your school project) the resulting fuel savings ensue through the fact that you only need to expend fuel to maintain air speed - basically, if the wind carries the surrounding air in your direction of travel, you have to travel shorter distances "through the air".
The mathematics underlying this consists of vector addition in the simple case and maybe addition of vector fields/line integrals in these vector fields for more complex cases. | Get yourself an [E6B](http://www.sportys.com/PilotShop/product/12654).
It has two sides.
One side is a simple circular slide rule, for doing all kinds of multiplication and division, for speed-time-fuel-flow problems.
You want the other side, which features a sliding card and a transparent disk overlay on it, on which you can make pencil marks.
What it does is solve the "wind triangle", which is just a vector sum.
If the aircraft is heading North, say, at a speed of 100 knots, and the wind is from the southwest at a speed of 30 knots, meaning the air containing the aircraft is moving Northeast at 30 knots, those two vectors are added to get the aircraft's actual motion vector over the ground, which is roughly to the East of North, and roughly 120 knots.
(A knot is one nautical mile per hour. A nautical mile is about 15% larger than a statute mile, and it is defined as 1 minute, i.e. 1/60 of a degree, of latitude. It is used because it makes navigation easier, because charts have latitude/longitude lines.)
What pilots do with that is determine the correction angle they need to use to fly in the direction they want to go, and the ground speed tells them how long it will take to get there.
It's a little more complicated than that, of course.
They have to account for magnetic compass variation, and the fact that wind speeds generally increase with altitude.
Now with GPS gear, it takes a lot of the guesswork out of enroute navigation, but in terms of flight planning, they still need to deal with wind, time-of-flight, fuel, etc. |
1,184 | For a school project, I'm trying to make an automated flight planner, considering mainly the differences in flight paths according to wind.
Now I've heard that flying with/against the wind affects airspeed. But I really don't know any specific(even empirical) laws on determining by how much it does so.
What's more, I've also heard about gas savings through these effects. That I would have pretty much no idea of how to calculate but that's less important.
Basically if anyone can point me in the right direction to figure out how to figure out solid speed gains, I'd be grateful, even moreso if I can find out the theoretical origins of such laws.
(The only thing I found that I think is close to what I want is [this](http://en.wikipedia.org/wiki/E6B), but I have no clue what the laws derive from) | 2010/11/21 | [
"https://physics.stackexchange.com/questions/1184",
"https://physics.stackexchange.com",
"https://physics.stackexchange.com/users/579/"
] | For your purposes, you can simply assume that the airplane travels at a constant velocity through the air mass. "Wind" simply means that this air mass is moving with respect to the ground.
If the airplane's velocity through the air is (a vector) v, and the air velocity with respect to the ground is a vector w, then the airplane's velocity with respect to the ground is simply v+w.
It's the same problem as swimming in a river with a current. If you are swimming directly upstream (or downstream), then the velocity of river water simply subtracts (or adds) to your velocity. If, on the other hand, you want to swim directly across, without floating downstream with the current, you have to angle your swim slightly upstream so that the component of your velocity in the direction of the river flow cancels out the river velocity.
In flying, this correction is called the "wind correction angle"; it corrects for the crosswind component of the wind, in order to fly a straight path (relative to the ground) from point A to point B. If you google for "cross-country flight planning" you will find lots of materials about how this is done in practice. The old-fashioned way is to use the [E6B circular slide-rule](http://en.wikipedia.org/wiki/E6B), which you mentioned. The math is actually easier than that device/page might have you believe. The advantage of the E6B is that you can use it with one hand while you are flying an airplane.
If you assume that the wind is constant everywhere, then the problem is fairly trivial. If you assume that the wind is different from place to place and at different altitudes, and that the airplane's engine's efficiency is different at different altitudes, then the problem is more complex/interesting.
Where the wind really matters is when the airplane is transitioning from the ground to the air (and thus their relative velocities really matter!). Search youtube for "cross-wind landing" for some dramatic examples. | +1 on the notion that ground speed is the straightforward vector addition of air speed and wind speed.
Manual flight computers such as the classic Dalton E6B allow you to do this vector math graphically. From a starting point in the middle of your plastic plate you draw a line in the direction of the wind speed, with a length proportional to the wind speed. From there you draw a line in the direction of your air speed (which is your aircraft's heading), with a length proportional to your air speed. Then the vector from start to finish is your ground speed and your ground track (direction you are travelling over the ground).
Concerning the extra fuel you need to burn to fly into a headwind or the fuel you save by flying with a tailwind, a most practical consideration to note is that if you fly from pt. A to pt. B into a headwind, and then turn around and fly from B back to A with a tailwind of the same strength, you lose more flying into the headwind than you gain from flying with the tailwind. |
1,184 | For a school project, I'm trying to make an automated flight planner, considering mainly the differences in flight paths according to wind.
Now I've heard that flying with/against the wind affects airspeed. But I really don't know any specific(even empirical) laws on determining by how much it does so.
What's more, I've also heard about gas savings through these effects. That I would have pretty much no idea of how to calculate but that's less important.
Basically if anyone can point me in the right direction to figure out how to figure out solid speed gains, I'd be grateful, even moreso if I can find out the theoretical origins of such laws.
(The only thing I found that I think is close to what I want is [this](http://en.wikipedia.org/wiki/E6B), but I have no clue what the laws derive from) | 2010/11/21 | [
"https://physics.stackexchange.com/questions/1184",
"https://physics.stackexchange.com",
"https://physics.stackexchange.com/users/579/"
] | For your purposes, you can simply assume that the airplane travels at a constant velocity through the air mass. "Wind" simply means that this air mass is moving with respect to the ground.
If the airplane's velocity through the air is (a vector) v, and the air velocity with respect to the ground is a vector w, then the airplane's velocity with respect to the ground is simply v+w.
It's the same problem as swimming in a river with a current. If you are swimming directly upstream (or downstream), then the velocity of river water simply subtracts (or adds) to your velocity. If, on the other hand, you want to swim directly across, without floating downstream with the current, you have to angle your swim slightly upstream so that the component of your velocity in the direction of the river flow cancels out the river velocity.
In flying, this correction is called the "wind correction angle"; it corrects for the crosswind component of the wind, in order to fly a straight path (relative to the ground) from point A to point B. If you google for "cross-country flight planning" you will find lots of materials about how this is done in practice. The old-fashioned way is to use the [E6B circular slide-rule](http://en.wikipedia.org/wiki/E6B), which you mentioned. The math is actually easier than that device/page might have you believe. The advantage of the E6B is that you can use it with one hand while you are flying an airplane.
If you assume that the wind is constant everywhere, then the problem is fairly trivial. If you assume that the wind is different from place to place and at different altitudes, and that the airplane's engine's efficiency is different at different altitudes, then the problem is more complex/interesting.
Where the wind really matters is when the airplane is transitioning from the ground to the air (and thus their relative velocities really matter!). Search youtube for "cross-wind landing" for some dramatic examples. | Get yourself an [E6B](http://www.sportys.com/PilotShop/product/12654).
It has two sides.
One side is a simple circular slide rule, for doing all kinds of multiplication and division, for speed-time-fuel-flow problems.
You want the other side, which features a sliding card and a transparent disk overlay on it, on which you can make pencil marks.
What it does is solve the "wind triangle", which is just a vector sum.
If the aircraft is heading North, say, at a speed of 100 knots, and the wind is from the southwest at a speed of 30 knots, meaning the air containing the aircraft is moving Northeast at 30 knots, those two vectors are added to get the aircraft's actual motion vector over the ground, which is roughly to the East of North, and roughly 120 knots.
(A knot is one nautical mile per hour. A nautical mile is about 15% larger than a statute mile, and it is defined as 1 minute, i.e. 1/60 of a degree, of latitude. It is used because it makes navigation easier, because charts have latitude/longitude lines.)
What pilots do with that is determine the correction angle they need to use to fly in the direction they want to go, and the ground speed tells them how long it will take to get there.
It's a little more complicated than that, of course.
They have to account for magnetic compass variation, and the fact that wind speeds generally increase with altitude.
Now with GPS gear, it takes a lot of the guesswork out of enroute navigation, but in terms of flight planning, they still need to deal with wind, time-of-flight, fuel, etc. |
25,030 | Apple and Google are going head-to-head to define meaning of the three-horizontal-bars icon: 
In iOS this icon means "drag me to rearrange items in a list" while Google Chrome's version means "click me to bring up a menu".
Is one of these two meanings already widely established in mobile, web, or desktop software? Also, which popular apps (on any platform) use this icon and what does it mean in those apps?
I'm asking because we're building an app that has a "list re-order" feature (using the standard iOS icon of course!), but several iOS-familiar folks I talked with didn't recognize the re-order icon. This led me to wonder how popular either variant is. Even if an icon is iOS standard, if it's not used much and the other variant is very popular, then we'll have some user education challenges we want to prepare for.
Here's pictures from the newest Google Chrome:
From iOS [design guidelines](http://developer.apple.com/library/ios/#documentation/userexperience/conceptual/mobilehig/UIElementGuidelines/UIElementGuidelines.html#//apple_ref/doc/uid/TP40006556-CH13-SW1):
From a sample iOS app:
 | 2012/08/25 | [
"https://ux.stackexchange.com/questions/25030",
"https://ux.stackexchange.com",
"https://ux.stackexchange.com/users/11413/"
] | **Three bar icons are now being used widely to indicate a "show list/menu" function - it's not just Chrome.** Below are screenshots from Day One and PlaceMe (I only had to open a couple of apps to find examples of this usage).
 
I believe the icon was a poor choice by Apple (in hindsight) - it does not give a clear interaction cue, it's more of a reorderable state indicator. But, let's remember that Apple made this choice before all this app-madness happened.
On iOS, both uses may be able to co-exist without confusion - since use as a menu/list indicator would have a single icon and "reorderable state" would have an icon beside each list item.
A better choice may be to move toward something similar to the "draggable" icon to indicate reorder-ability and let the three bars be a "show list/menu" function cue - as it is gaining traction.
 | I agree that the three-lines icon is being established as a place to pull something. (See in particular the lined tab that appears if you drag down from the top of an iOS screen to show notifications, or on the lock screen when multiple notifications are waiting, or on the camera icon on the lock screen.)
Matching that icon to the real world examples of the battery door / sliding plastic widget makes sense to me. The Google Chrome icon confuses me for that reason, and I always thought a "gear" or similar "settings" related icon would have worked better there. |
25,030 | Apple and Google are going head-to-head to define meaning of the three-horizontal-bars icon: 
In iOS this icon means "drag me to rearrange items in a list" while Google Chrome's version means "click me to bring up a menu".
Is one of these two meanings already widely established in mobile, web, or desktop software? Also, which popular apps (on any platform) use this icon and what does it mean in those apps?
I'm asking because we're building an app that has a "list re-order" feature (using the standard iOS icon of course!), but several iOS-familiar folks I talked with didn't recognize the re-order icon. This led me to wonder how popular either variant is. Even if an icon is iOS standard, if it's not used much and the other variant is very popular, then we'll have some user education challenges we want to prepare for.
Here's pictures from the newest Google Chrome:
From iOS [design guidelines](http://developer.apple.com/library/ios/#documentation/userexperience/conceptual/mobilehig/UIElementGuidelines/UIElementGuidelines.html#//apple_ref/doc/uid/TP40006556-CH13-SW1):
From a sample iOS app:
 | 2012/08/25 | [
"https://ux.stackexchange.com/questions/25030",
"https://ux.stackexchange.com",
"https://ux.stackexchange.com/users/11413/"
] | **Three bar icons are now being used widely to indicate a "show list/menu" function - it's not just Chrome.** Below are screenshots from Day One and PlaceMe (I only had to open a couple of apps to find examples of this usage).
 
I believe the icon was a poor choice by Apple (in hindsight) - it does not give a clear interaction cue, it's more of a reorderable state indicator. But, let's remember that Apple made this choice before all this app-madness happened.
On iOS, both uses may be able to co-exist without confusion - since use as a menu/list indicator would have a single icon and "reorderable state" would have an icon beside each list item.
A better choice may be to move toward something similar to the "draggable" icon to indicate reorder-ability and let the three bars be a "show list/menu" function cue - as it is gaining traction.
 | Over the years, things have changed somewhat.
Chrome has changed its menu icon to three vertical dots to comply with the Material Design HIG:
[](https://i.stack.imgur.com/k8O3X.png)
Apple has changed its drag-and-drop icon to be visually distinct from the hamburger:
[](https://i.stack.imgur.com/7JFYv.png)
Though the hamburger icon still isn't used consistently (e.g. Firefox and Gnome use it as a generic menu icon), both Microsoft and Google use it for navigation menus. (Apple doesn't seem to use this icon anywhere.)
You can see the icons being used in the navigation drawer recommendations in both the [Material](https://material.io/guidelines/patterns/navigation-drawer.html#) and [Fluent](https://docs.microsoft.com/en-us/windows/uwp/design/controls-and-patterns/navigationview) HIGs. |
25,030 | Apple and Google are going head-to-head to define meaning of the three-horizontal-bars icon: 
In iOS this icon means "drag me to rearrange items in a list" while Google Chrome's version means "click me to bring up a menu".
Is one of these two meanings already widely established in mobile, web, or desktop software? Also, which popular apps (on any platform) use this icon and what does it mean in those apps?
I'm asking because we're building an app that has a "list re-order" feature (using the standard iOS icon of course!), but several iOS-familiar folks I talked with didn't recognize the re-order icon. This led me to wonder how popular either variant is. Even if an icon is iOS standard, if it's not used much and the other variant is very popular, then we'll have some user education challenges we want to prepare for.
Here's pictures from the newest Google Chrome:
From iOS [design guidelines](http://developer.apple.com/library/ios/#documentation/userexperience/conceptual/mobilehig/UIElementGuidelines/UIElementGuidelines.html#//apple_ref/doc/uid/TP40006556-CH13-SW1):
From a sample iOS app:
 | 2012/08/25 | [
"https://ux.stackexchange.com/questions/25030",
"https://ux.stackexchange.com",
"https://ux.stackexchange.com/users/11413/"
] | drag'n'drop nearly always has bad affordance.
The current model in gmail is the following:
Albeit I'm not sure if they're really serious about it, esp. as it only appears to the hovered element.
The previous one was this:
More dragg-ish, but still bad.
I think in order to reach good affordance with a drag-n-drop control, it either has to be explicit action (up and down arrows, that's pretty explicit), or it has to be "bumpy" (in case of a touchscreen): I guess the apple version looks more like a kind of air venting holes than something to get a hold on.
The drag-n-drop affordances usually come from hardware switches and battery cover lids, and **this is what those three "lines" mean** (they're the "receded" type). But even if you do miss them for 3 lines (compared to Chrome, which *are* three lines), then we shouldn't expect the users to understand...
Here are a few examples from 'real life':
*A bumping-out battery lid (from [here](http://www.cameraspareparts.co.uk/kodak-easyshare-cx4310-battery-door-cover-lid-4857-p.asp))*
*A dotted battery lid (from [here](http://www.google.com/imgres?q=battery%20cover%20lid&um=1&hl=en&safe=off&client=safari&rls=en&authuser=0&tbm=isch&tbnid=Nr6XnQjLUl36tM:&imgrefurl=http://www.cameraspareparts.co.uk/genuine-fuji-s602-zoom-battery-door-lid-cover-3419-p.asp&docid=BPF0SeW8kScFIM&imgurl=http://www.cameraspareparts.co.uk/ekmps/shops/eurohitech/images/genuine-fuji-s602-zoom-battery-door-lid-cover-3419-p.jpg&w=254&h=300&ei=XSY4UIixKI_04QTdvIHQDA&zoom=1&iact=hc&vpx=214&vpy=12&dur=369&hovh=105&hovw=91&tx=90&ty=95&sig=113919221410405905380&page=1&tbnh=105&tbnw=91&start=0&ndsp=24&ved=1t:429,r:9,s:0,i:101&biw=1279&bih=549))*
*A receding battery lid (from [here](http://www.cameraspareparts.co.uk/kodak-easyshare-c190-silver-battery-door-cover-lid-cap-4872-p.asp))*
You can also create the following interaction if you don't fear of breaking out of native:
Because of the arrows, the users will immediately understand what is it for (I hope so, this is just a mockup, no user tests yet), and they'll try to tap on it as part of exploring the interface. If you do it well enough, they'll notice the displacement (likely if it happens somewhere between 150-250msec after touchstart), and will understand that it's a tap movemenent.
This is just a tip. Norman's classic "*The Design Of Everyday Things*" might help you out on this. | I agree that the three-lines icon is being established as a place to pull something. (See in particular the lined tab that appears if you drag down from the top of an iOS screen to show notifications, or on the lock screen when multiple notifications are waiting, or on the camera icon on the lock screen.)
Matching that icon to the real world examples of the battery door / sliding plastic widget makes sense to me. The Google Chrome icon confuses me for that reason, and I always thought a "gear" or similar "settings" related icon would have worked better there. |
25,030 | Apple and Google are going head-to-head to define meaning of the three-horizontal-bars icon: 
In iOS this icon means "drag me to rearrange items in a list" while Google Chrome's version means "click me to bring up a menu".
Is one of these two meanings already widely established in mobile, web, or desktop software? Also, which popular apps (on any platform) use this icon and what does it mean in those apps?
I'm asking because we're building an app that has a "list re-order" feature (using the standard iOS icon of course!), but several iOS-familiar folks I talked with didn't recognize the re-order icon. This led me to wonder how popular either variant is. Even if an icon is iOS standard, if it's not used much and the other variant is very popular, then we'll have some user education challenges we want to prepare for.
Here's pictures from the newest Google Chrome:
From iOS [design guidelines](http://developer.apple.com/library/ios/#documentation/userexperience/conceptual/mobilehig/UIElementGuidelines/UIElementGuidelines.html#//apple_ref/doc/uid/TP40006556-CH13-SW1):
From a sample iOS app:
 | 2012/08/25 | [
"https://ux.stackexchange.com/questions/25030",
"https://ux.stackexchange.com",
"https://ux.stackexchange.com/users/11413/"
] | drag'n'drop nearly always has bad affordance.
The current model in gmail is the following:
Albeit I'm not sure if they're really serious about it, esp. as it only appears to the hovered element.
The previous one was this:
More dragg-ish, but still bad.
I think in order to reach good affordance with a drag-n-drop control, it either has to be explicit action (up and down arrows, that's pretty explicit), or it has to be "bumpy" (in case of a touchscreen): I guess the apple version looks more like a kind of air venting holes than something to get a hold on.
The drag-n-drop affordances usually come from hardware switches and battery cover lids, and **this is what those three "lines" mean** (they're the "receded" type). But even if you do miss them for 3 lines (compared to Chrome, which *are* three lines), then we shouldn't expect the users to understand...
Here are a few examples from 'real life':
*A bumping-out battery lid (from [here](http://www.cameraspareparts.co.uk/kodak-easyshare-cx4310-battery-door-cover-lid-4857-p.asp))*
*A dotted battery lid (from [here](http://www.google.com/imgres?q=battery%20cover%20lid&um=1&hl=en&safe=off&client=safari&rls=en&authuser=0&tbm=isch&tbnid=Nr6XnQjLUl36tM:&imgrefurl=http://www.cameraspareparts.co.uk/genuine-fuji-s602-zoom-battery-door-lid-cover-3419-p.asp&docid=BPF0SeW8kScFIM&imgurl=http://www.cameraspareparts.co.uk/ekmps/shops/eurohitech/images/genuine-fuji-s602-zoom-battery-door-lid-cover-3419-p.jpg&w=254&h=300&ei=XSY4UIixKI_04QTdvIHQDA&zoom=1&iact=hc&vpx=214&vpy=12&dur=369&hovh=105&hovw=91&tx=90&ty=95&sig=113919221410405905380&page=1&tbnh=105&tbnw=91&start=0&ndsp=24&ved=1t:429,r:9,s:0,i:101&biw=1279&bih=549))*
*A receding battery lid (from [here](http://www.cameraspareparts.co.uk/kodak-easyshare-c190-silver-battery-door-cover-lid-cap-4872-p.asp))*
You can also create the following interaction if you don't fear of breaking out of native:
Because of the arrows, the users will immediately understand what is it for (I hope so, this is just a mockup, no user tests yet), and they'll try to tap on it as part of exploring the interface. If you do it well enough, they'll notice the displacement (likely if it happens somewhere between 150-250msec after touchstart), and will understand that it's a tap movemenent.
This is just a tip. Norman's classic "*The Design Of Everyday Things*" might help you out on this. | Over the years, things have changed somewhat.
Chrome has changed its menu icon to three vertical dots to comply with the Material Design HIG:
[](https://i.stack.imgur.com/k8O3X.png)
Apple has changed its drag-and-drop icon to be visually distinct from the hamburger:
[](https://i.stack.imgur.com/7JFYv.png)
Though the hamburger icon still isn't used consistently (e.g. Firefox and Gnome use it as a generic menu icon), both Microsoft and Google use it for navigation menus. (Apple doesn't seem to use this icon anywhere.)
You can see the icons being used in the navigation drawer recommendations in both the [Material](https://material.io/guidelines/patterns/navigation-drawer.html#) and [Fluent](https://docs.microsoft.com/en-us/windows/uwp/design/controls-and-patterns/navigationview) HIGs. |
37,930 | We are building a ecommerce with a inventory of about 6000 products, the problem is most of the products have the same description so we decided to keep description as `noindex` and make it available to users to prevent the issue of duplicate content.
I heard that it will be a big impact if there is no product description how to tackle this problem, is this true? | 2012/11/16 | [
"https://webmasters.stackexchange.com/questions/37930",
"https://webmasters.stackexchange.com",
"https://webmasters.stackexchange.com/users/19987/"
] | If you have no descriptive text for your products you will have lots of "thin content" pages that will not be viewed favorably by search engines such as Google.
On the other hand, if you have repeated descriptions you will have lots of "duplicate content" that will not be viewed favorably, either.
Unfortuantely, there simply is no automated solution to this. You should try to create custom descriptions for each product. You may be able to use a server-side algorithm for some of this. You also can encourage user-generated content such as reviews and ratings to increase the uniqueness of each page.
If that is simply not possible, as a last resort I would try to eliminate thin & duplicate content issues by simply refusing to give each product its own URL. Organize products by categories and display multiples per page... this will ensure that all of your pages have worthwhile and non-duplicate content. (Ideally each product has a unique URL, but if you cannot fill unique content it is better to avoid that altogether.) | What do you mean you decided to keep descriptions as noindex? Isn't the product description displaying on the product page? If you don't have product descriptions setup product features so that each page has an ordered list of features of the product. Color size etc. |
37,930 | We are building a ecommerce with a inventory of about 6000 products, the problem is most of the products have the same description so we decided to keep description as `noindex` and make it available to users to prevent the issue of duplicate content.
I heard that it will be a big impact if there is no product description how to tackle this problem, is this true? | 2012/11/16 | [
"https://webmasters.stackexchange.com/questions/37930",
"https://webmasters.stackexchange.com",
"https://webmasters.stackexchange.com/users/19987/"
] | If you have no descriptive text for your products you will have lots of "thin content" pages that will not be viewed favorably by search engines such as Google.
On the other hand, if you have repeated descriptions you will have lots of "duplicate content" that will not be viewed favorably, either.
Unfortuantely, there simply is no automated solution to this. You should try to create custom descriptions for each product. You may be able to use a server-side algorithm for some of this. You also can encourage user-generated content such as reviews and ratings to increase the uniqueness of each page.
If that is simply not possible, as a last resort I would try to eliminate thin & duplicate content issues by simply refusing to give each product its own URL. Organize products by categories and display multiples per page... this will ensure that all of your pages have worthwhile and non-duplicate content. (Ideally each product has a unique URL, but if you cannot fill unique content it is better to avoid that altogether.) | It all boils down to what you're planning to do and what your expectations are (and whether they're realistic).
Your website isn't up yet, and the question you should ask yourself is: are you expecting to receive traffic from Google? Getting customers to find your website through some search engine?
If the answer is yes, then don't start with an inventory of 6,000 thin pages. It won't work. Been there, done that.
A strong domain would probably be able to rank, regardless of thin content. However, if you're starting a new business, don't let Google decide your website is low quality. Start slowly, add your own content and **do SEO wisely**. Don't regret wrong decisions. Adding content takes time. A lot of it, so plan ahead, and focus on things that you can actually sell.
Take advantage of paid advertising, combined with your SEO efforts, unless you're ready to wait for your first sale.
By the way, Google is pretty smart at detecting automated content, ie "We have the best [product name] at the lowest prices". So that approach is certainly not going to work. |
267,741 | I autoresolved a battle against a rebellion and got a shiny new mortar.
After several manual tries on the same battle, I have been unable to actually capture any artillery myself.
How does that work? What do you have to do? | 2016/06/02 | [
"https://gaming.stackexchange.com/questions/267741",
"https://gaming.stackexchange.com",
"https://gaming.stackexchange.com/users/28546/"
] | My understanding is as follows -
* The army you are fighting against must be of the same faction
* The artillery crew must be wiped out and there artillery pieces intact
* You must have a spare unit slot at the end of the battle
Many people have stated that there is an element of randomness too. Some have quoted roughly a 10% chance to capture and this is decided before the battle so replaying the same battle over and over will likely end in the same result. | After several manual battles i only get one capture art. I send one unit to attack them , forget that unit and battle finish while my unit was close, attacking the abandoned machines.
But others battles didnt work |
133,125 | Are there any other IDEs worth my time for Lotus Notes development? We're doing mostly LotusScript development and would kill for features of Eclipse or Visual Studio, like "Show Declaration". I know there's [an Eclipse plugin for Java development in Notes](http://www.ibm.com/developerworks/lotus/library/notes-eclipse/), but seems like it *only* does Java, and we have too many pieces of legacy code in LotusScript to abandon it. | 2008/09/25 | [
"https://Stackoverflow.com/questions/133125",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/6897/"
] | The closest thing you're going to find is the [Teamstudio LotusScript Browser](http://www.teamstudio.com/support/free-utilities.html).
It's not very good, but it is free and that almost makes up for it.
Features:
1. No support for keyboard shortcuts.
2. Not completely integrated into the designer so is a bit sluggish.
3. Only works in script libraries
4. It does have Find Definition and References functionality which are almost useful.
There is also a rumored LotusScript plug-in for eclipse. | Teamstudio sell a number of tools to assist your Lotus Notes development, and it looks like they can do some of the things you want, but it doesn't look like they can be assembled into an IDE.
<http://www.teamstudio.com/products/product-index.html>
(Disclosure: I worked for a sister company of Team Studio a number of years back, but never had much to do with their products) |
133,125 | Are there any other IDEs worth my time for Lotus Notes development? We're doing mostly LotusScript development and would kill for features of Eclipse or Visual Studio, like "Show Declaration". I know there's [an Eclipse plugin for Java development in Notes](http://www.ibm.com/developerworks/lotus/library/notes-eclipse/), but seems like it *only* does Java, and we have too many pieces of legacy code in LotusScript to abandon it. | 2008/09/25 | [
"https://Stackoverflow.com/questions/133125",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/6897/"
] | Lotus Notes has moved to the Eclipse platform in version 8. You can run the client in 2 different modes, basic mode which is the version we all know or on the Eclipse platform (know as the standard). The IDE is also moving to eclipse, version 8.5 beta 2 is currently available with the new Eclipse based IDE. Bear in mind that it's a Beta version and it's not feature complete. | The closest thing you're going to find is the [Teamstudio LotusScript Browser](http://www.teamstudio.com/support/free-utilities.html).
It's not very good, but it is free and that almost makes up for it.
Features:
1. No support for keyboard shortcuts.
2. Not completely integrated into the designer so is a bit sluggish.
3. Only works in script libraries
4. It does have Find Definition and References functionality which are almost useful.
There is also a rumored LotusScript plug-in for eclipse. |
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