Providing a link to a question and the system recognizing your user?

Question: I am thinking about providing a link to a question, but I have one question before doing so. How can you provide the link with it recognizing your user? I know that in area 51 you can create your own unique url so that it will recognize that you referred all users who clicked that link, but what about in a beta/launched site? Apparently you can earn this badge if your link gets clicked on by 25 unique IP addresses in 3 days. But how can it tell which user is providing the link? Is there something extra I have to do? If so, what?
Comment: Please do announce your questions or indeed answers - it helps get the word out and will increase awareness of the site :)
Answer: Click "link" under the question to get a permalink that identifies you as the referer. This URL embeds your user ID.
Answer: The format used by the "link" function is https://bricks.stackexchange.com/q/<question ID>/<user ID>, but you can type it yourself as well.
Note that answers and questions share the same ID space, so you can also refer to answers that way — the "link" function there seems to forget to include your user ID.


I am trying to display two live video screens as one live screen "layered" "not side by side"

Question: I have a live screen on my computer from a video camera, and a live screen on my computer from a spectrum scope, see http://www.youtube.com/watch?v=RFPojOo-hI4  for a video of this display.
I want to layer the top portion of the scope screen "the part with spikes, not vertical bars"
onto a screen with the live video camera screen, so that on one screen a live video is shown with the frequency wavelength moving across it "in a park showing a bench with the frequency moving across it"
and so that on another window, "i assume by making each window smaller i can display two screens side by side"
i can show the entire scope display.
What is the name of a computer program that allows me to do this?
If there are none, what is the name of a program that allws me to develop my own program to do this?
it should be simple, as i am just trying to display two feeds "inputs" on one screen
Answer: With compiz windowmanager (linux) you can just move the windows on top of each other and increase the transparancy for the topmost window. Only one windo will have the focus, of course.
The opacity plugin has a default key/mouse shortcut Alt+ScrollWheel


Are colleges prepared to offer a PhD position to one who already has a PhD

Question: I am a PhD holder in Analytical Chemistry from Iran and now, I am very interested in applying for a PhD program in a somewhat different field like Nanotechnology in the US and Canada. I have invested much time and effort on preparing for taking GRE and TOEFL exams and I have a strong research background, but now I heard recently from one of my professors that most institutions are not prepared to offer a PhD position to one who already has one PhD. Could you say more about this issue? Is this true?
Comment: See [Is doing two PhDs a good path](http://academia.stackexchange.com/questions/17232/is-doing-two-phds-a-good-path)
Comment: Another issue to consider is whether immigration authorities will be willing to grant you a student visa to study for a second PhD.
Answer: Certainly, it happens. I am currently pursuing a second PhD myself, in a field very different from my first. I just learned that one of my fellow graduate students in our department also has an earlier PhD, and hers is from a field very close to our department's.
As the thread linked by ff524 notes, there are many people who wish to earn a second PhD for all the wrong reasons. But you didn't ask whether it was a good idea to earn a second PhD, you asked whether Universities would admit you. The answer is that many will, but they certainly may be wary of this aspect of your application. As commenters have pointed out below, some universities flatly will not consider your application. Amongst those that will consider your application, some admissions committees will not like your previous degree, and others will not care. In my case, I felt the admissions committee did not really care about my earlier degree; they cared about my ability to demonstrate potential in my new field.
Furthermore, before applying to my current institution, I emailed roughly eight departments asking whether an application someone such as myself would be welcomed. Every single one of them replied to me to say that yes, it would; and several were encouraging about my prospects if I did apply.
Nonetheless you should be prepared to accept that some admissions committees will not like your previous degree, and you should be prepared to explain to them your good reasons for pursuing a second PhD.
Comment: Actually, some universities do have rules that a person who already has a PhD may not be admitted into a PhD program (even in a different field), regardless of how well qualified they are otherwise.  Exceptions may be possible, but I think a blanket "they will" overstates the case.
Comment: As @NateEldredge comments, some universities in the U.S. will simply not consider admitting anyone into a PhD program who already has a PhD. My own large state R1 university will not, for example.
Comment: @NateEldredge: I agree, but why not?
Comment: @NateEldredge Fair point; I have edited to make that point clear in my answer.
Answer: It depends. For example, in CS, some top schools don't allow this, like stanford MIT berkeley, etc. You should look carefully at the websites.


Can anyone explain why dividend income shot up during 2009-10 and then back down in 2010-11

Question: I'm reading a report about the effects of the introduction of the additional income tax rate in the UK, which was released in 2010 which can be found here. Table 5.1 shows a sudden jump in dividend income, followed by a sudden drop, during 2009-11 but the report only describes this as forestalling behaviour, can anyone explain why this happen. Is it because investors who were earning income just above the additional rate were trying to lower their income by placing their wealth in dividends before the arrival of the additional income tax rate
Answer: The document refers to an increase in the top tax rate in the UK. And I think the comment below Table 5.1 answers your question:

As shown, there was a significant increase in dividend income in
  2009-10 followed by a corresponding fall in 2010-11. This is thought
  to be the main source of the forestalling behaviour as it is the main
  source of income for owner-directors of companies who have much more
  flexibility than others in terms of the timing of their remuneration.

Basically it means that company directors saw this coming, and chose to increase dividends artificially in the short term to get ahead of the increase in taxes that would soon be imposed on them.
Dividends are a form of income, so company directors (who are also often shareholders) are in the unusual position of being able to decide their own income. They simply did the rational thing in this instance and chose to increase their pay in the short term in order to avoid some of the new taxes.
Comment: One definition of forestalling is "to act in advance of (someone) in order to prevent them from doing something.". It looks like the owners of small companies in the UK acted before the tax increase to (partially) counter its effect by declaring a bigger dividend to themsleves one year and a lower one the next.


Difference between acoustic emissions and ultrasonic waves

Question: I need some clarification about the difference between acoustic emissions and ultrasonic waves. I have the idea that both are high-frequency signals and informative frequency bands more or less overlap.  Is there any difference between the waveform or in other characteristics that may the propagation speed through a medium. Moreover, will the velocity of both the signals through a medium (carbon steel) will be the same or will there be any difference.
Answer: The propagation of a mechanical wave within a medium depends on the characteristics of that medium (e.g. density).
An easy way to experience this is to knock a piece of material with a sharp hit and listen to it trying to dissipate the energy you gave it. Consider for example a bell. When you hit it, it goes bonnnnnnnnnnng at some tone. If you were to weld a few rings around the bell and try to hit it again, it would go bonng. Different density / stifness of the material, different sound.
Acoustic emissions are akin to the sound of the bell and the cause of the "ringing" are the internal cracks. Consider for example the sound of ice cracking (similar sounds are produced even as ice cracks on its own, without forcing it externally) or even closer to your question, glass cracking under thermal shock.
Within a block of ice, the acoustic emissions are low enough in frequency that can be heard. But, if that was a piece of kevlar breaking, the disturbance would propagate with different characteristics through the material. You can see that we are already at hundreds of kHz in this case and we would be needing special equipment to sense the material vibrating.
Hope this helps.
Comment: Thanks for the detailed explanation. In my case, I have a carbon steel vessel. I recorded AE signals from the vessel having a crack. I calculated the velocity of the signals through simple distance, time formulation. The resulting velocity of the AE signals in my case is 3000m/sec. Whereas, in the data sheets if we check the ultrasonic velocity of the carbon steel is 6000 m/sec. Is this difference justifiable as I am performing acoustic emission testing (Acoustic sensors) not the ultrasonic testing (material is tested using ultrasonic waves and the apparatus used is different)?
Comment: @shobi Glad to hear you found this useful. From the clarification you provide here, you are after something slightly different. The velocity differences you provide are enormous. Is the crack partial or through the vessel? The crack would change the direct path between sensors and that is how the velocity seems to change. Here, it seems that the crack has doubled the distance between the projector and the sensor (?) If possible, look for reflections, after the main hit.


Turn facebook account into normal account

Question: When I registered for stackoverflow.com, I used the option "log in with Facebook". Now I wonder, if someday I delete my Facebook account, what happens with my account here? Does he get deleted too? Or is there a way to transform it in an account with username/passowrd?
Answer: You can add other open ID providers to your account. Each of these can identify you, so if you delete your account from one provider, you can still log on.
Manage this from the my logins link on your profile page:
Answer: You can associate another OpenID with your account.
Click on "my logins" in your profile to add another id.


Remote Debugging in Visual Studio: Symbol file does not match the module

Question: I've been scouring the net trying to find an answer to this question, but all other suggestions don't work.
I have a C# .net 3.5 dll that is an add-in to another program. The program calls the dll when the user presses a certain button. My tool is having an error that is related to the specific setup of the users computer (unrepeatable on mine) so I want to remote debug it.
I have setup debugging tools (2010, but have also tried in VS 2008 for the same result) on the remote PC, and run my DLL. I then go to Debug > Attach to Process, select the remote PC, select the exe 'Revit.exe' that hosts my dll, and it attaches ok. But I can't set any breakpoints or anything as it says there are no symbols loaded. (red unfilled circle with /!)
I open the modules window, right click on my DLL 'PLT2.dll' and try and load the symbols from the symbol path, I select the PDB file which is situated on the network drive right next to the DLL and it says it does not match the module.
I have tried the following based off suggestions I've found on the net:

Checked that the code is not set to optimize, and that output debug info it set to full.
PDB file definately matches the DLL, I deleted them all, and rebuilt it.
The path to symbols on both computers is the same
Enabled Just My Code

Has anyone got any ideas on what I could do?
Answer: Could the remote machine be picking up a different version of your binary?
If you remove all the info you added in the Symbols Settings dialog, which path does the modules window show the binaries being loaded from?


air conditioner venting pipe functionality

Question: Today I found the venting pipe of air conditioner pump out hot air out of my house. I wonder if it will cause energy leak. If it's hot air, is it better to pump it inside my house?
Comment: ummmm... why do you think the air is hot in the first place?  What do you think an air conditioner does?
Answer: No, it is not better to pump the hot air into your house. The vent is outside for a reason and by-code because it will also expel condensate (ie water vapor condenses out of the air when the pump compresses air.)
If you are worried at all about 'energy leaks' then ensure the drain pipe has an escutcheon and it seals tightly to the exterior wall so that drafts/cooling loss don't run up your power bill.  You can use a paintable, water-tight, exterior caulk to seal the escutcheon to the wall, if necessary.
Answer: I'm going to assume you're running the heat, and you're losing some of it out of the ~3/4" AC condensate line. That would not be desirable. It's supposed to have a trap on it, ideally one that has snap caps on it to use as a clean out. E.g., an "EZ-Trap", which you could open up and fill with water if it dries out, to prevent heat loss.
Or make your own out of pipe. In the picture below, the AC unit would be on the right.

(source, How to Properly Install a Condensate Line Trap)
But if you're talking about the ~2" exhaust pipe that's pumping warm moist air outside, DO NOT feed it back into your house as that would be a CO hazard.


What do you think about the new tags "ne" and "ci"?

Question: The tags "ne" and "ci" were created with this question: The use of ci when specifying locations. At first, I thought that it was unnecessary to keep such specific tags, but some people have expressed the opposite belief in a comment to that question. I would like to know what do you think about that.
Comment: I changed the tags into "particles".
Comment: I definitely agree with @DaG, it is ridiculus to create a tag for a specific word. We moderators shoul clean that question as soon as possible.
Comment: OK @martina!  And do you think we should create the tag "particles"  instead of these tags?
Comment: Yes, I do. Particles, at least in Italian are all those small synctactic words whose aim is to link two other synctactic elements and which do not have any standalone meaning, nor they fall in any of the regular syntax categories. Examples are ci, si, ne.
Answer: I understand that ne and ci may be troublesome for learners of Italian, but having a tag for every single troublesome word (irregular verbs, ambiguous nouns, prepositions with or without articles and so on) would lead to thousands of them, and then they wouldn't be more useful than just searching for that word in the existing corpus of questions and answers.
I am strongly in favour of higher level tags: if one has a doubt about a difficult pronoun/particle, they may just look for "pronouns" or "particle" (if we deem this a suitable tag).
Comment: Agreed. We should introduce specific tags for a category, not for separate words. So, an umbrella tag, such as "particles", would be better than two different tags "ci" and "ne".
Comment: I also agree with this view,  but I would like to know the opinion of other users.  On the other hand, we should think about how to define "particles" if we decide to introduce this tag. For me the definition isn't clear at all.
Answer: Here are some thoughts on why ci and ne should be tags:

Commonly, ci and ne are taught as specific topics in Italian textbooks.
They are problematic for people learning Italian as their usage is complex. Italian learners may want to browse all discussions for mention of these words.
Though they are used either as adverbs or pronouns, they technically fall into their own category of small, invariable words with little to no meaning known as particles. (Perhaps particles should be its own category as well.)
Comment: I know I am off topic with respect to this question, but I'd rather say that a word such as *ne* is *both* a pronoun and an adverb, depending on how it is used, just like *vecchio* is both a noun (*ho incontrato un vecchio*) and an adjective (*c'è un vecchio albero*), or *sopra* is both an adverb (*oggi mangiamo sopra*) and a preposition (*il quadro è sopra il tavolo*).


Do passenger lists for departures from the UK exist pre 1890?

Question: Findmypast.co.uk has passenger lists for ships departing from the UK beginning in 1890. What about dates before 1890? Do the records exist anywhere? I'm particularly interested in departures to the US in 1855.
Comment: As it stands this question is rather general.  It is good that you have identified the time frame, the 1850s.  Destination country and a bit more specific information on possible place of departure (e.g. England, Scotland, Ireland) would also narrow down the question.
Answer: The FMP lists come from series BT27 at The National Archives (for the UK, at Kew). The Catalogue notes for BT27 say "Lists earlier in date than 1890 have not survived."
Other documents re emigration survive with occasional mentions of names - TNA guides on emigration and emigrant records can be found on the TNA site.
Caveats:

The document guides describe stuff at Kew, which is not generally on-line (not surprisingly);
If anyone else picks up references in this query to ships leaving the UK and gets interested, be aware that lots of voyages from 1890 on were not recorded in the BT27 ledgers. All traffic between mainland Britain and Ireland was excluded (initially this was internal to the UK) as was purely European traffic.
Comment: Details of series BT27 at TNA are [here](http://discovery.nationalarchives.gov.uk/SearchUI/Details?uri=C3070).
Comment: Now that I understand what BT references are, and how to look them up, I won't need to ask questions like this in the future. Thanks!
Comment: Are these lists mentioned departures to America or to all parts?
Comment: William - working from memory, they are to all parts of the globe except "Europe". Exact definition of Europe not known to me. As I said above, Ireland is also excluded as either part of the UK or as part of Europe.
Answer: Try looking through the Immigrant Ships Transcribers Guild. It's not the best-organized site for exploring, but you can start here: http://immigrantships.net/departures/england.html
Comment: Thanks. That will be a good resource to remember. It looks like the lists for voyages pre 1890 from the UK are of the arrivals, not departures.
Comment: You're right; sorry.
Answer: As you mention the time period 1855, did your ancestors originate from Scotland?  The Highlands and Islands Emmigration Scheme assisted 5000 people to emmigrate from western Scotland to Australia.  The online database is at http://www.scan.org.uk/researchrtools/emigration.htm
Consider why the people emmigrated.  Although passenger lists may no exist, records associated with the reason for the move may still exist eg assisted travel, criminal transportation, colonisation.


What is "terrain mesh generation" exactly?

Question: I'm new to computer graphics and need to know and understand what the "terrain mesh generation" is? I read about "terrain", "mesh", "terrain generation" but can't find an article named "terrain mesh generation". So is there anyone can explain "terrain mesh generation" ?
Comment: it´s only a system for generating the terrain mesh. In other words: Mesh = a collection of vertices and polygons.
Terrain = a collection of meshes for a terrain.
So in this case it only generates a lot of meshes that builds up the terrain.
Answer: Terrain mesh generation is a general term for the process of... generating a mesh for the terrain.
Ok, let me elaborate.
A mesh is a generic term for a 3D model. It usually consists of vertex positions (set up as triangles), normals, texture coordinates and other information required to render the model properly. If you don't know how meshes work, you need to look into this first - this is part of the very basics of 3D rendering.
So, if a mesh is just a 3D model, why are terrains so special? For several reasons.
Terrains are usually not edited entirely by hand. Even if you want to design a specific part of your terrain by hand, most of it will be procedural (computer generated based on certain inputs). This is also important because terrains can be very large (pseudo-infinite), so creating it by hand is even less feasible. Proceduralism is a great form of compression: even infinite (or really large) terrains can be compressed down to a few integers.
Terrains also have another important property: most of the time you cannot go under them, so they can be described as a surface instead of a volume. The most common representation of this is the height-map: for each coordinate, you define the height of the terrain. This heigh-map can be procedurally generated, manually edited, infinite or finite. The heightmap also implicitly holds the surface normals.
So the process of terrain mesh generation most often refers to the process of taking the "compressed", procedural, perhaps height-mapped representation of the terrain and turning it into a 3d mesh. Of course the exact procedure depends on the system: you can generate only a few chunks of the terrain that is visible to the camera, you can have a dynamic LOD/tessellation system that makes the most visible parts more detailed than the rest, etc. So it really is just a generic term.
Answer: A mesh is a collection of points, usually connected into triangles, that form a shape in a (typically) 3-dimensional space.
A terrain mesh is a shape that is formed to resemble some terrain a video game or simulation; it can represent a landscape or even a whole planet.
So, generation of such mech involves creation of such vertices. There's a number of techniques used, such as Simplex/Perlin noise functions, that can be used to produce nicely-looking "Earth-like" terrain with minimal seed data. The term grabs all these methods and the result representation.


What does "20/ln(2)" mean in logistic regression?

Question: I am trying to understand Logistic Regression in relation to credit scoring model. I wish to understand the significance of "20/ln(2)" in logistic regression. Why and how is it used?
Comment: Could you please give a www link how 20/ln(2) is applied? Thanks!
Comment: Looks like a simple transformation (on a linear scale) http://bit.ly/klhGCr
Answer: This is a common scaling factor used for credit scoring models built with logistic regression.
The interpretation of the dependent variable in logistic regression is as log odds, but in credit scoring, we like to deal in points, thus a scaling factor is applied to the log odds to convert to the point system.
A widely used convention in credit scoring is the concept of "Points to Double the Odds" (often abbreviated PDO), and this is the source of the $\ln (2)$ in the question.  For example, how many points does the score change if the odds increase from 100:1 to 200:1.
A common default value for PDO is 20, because it produces credit score ranges that people tend to like.
So, the interpretation of the $20/\ln(2)$ is that for a 20-point increase in score, the odds double.
Answer: Typically in credit scoring one would choose a baseline score e.g. 600. We assign a certain meaning to 600 for example, 600 means the good bad odd is 30:1 (where bad typically means a default, the default definition is typically 90 days past payment due on the loan, however the bad definition can vary). Typically they also define that a 20 point jump means doubling of odds, for example 620 means the good bad odd if 60:1 and 640 is 120:1 etc. This definition comes from logistic regression.
If we fit a logistic regression model the model being fitted is this
$$\log(p/(1-p)) = a + b_1d_1 + \cdots + b_n  d_n$$
where $a$ and $b_i$ are parameter estimates and $p$ is the probability of good $d_i$ are your raw data (explanatory variables). The LHS is the log good bad odds. To conform to the above mentioned standard (i.e. 600 is 30:1 and 620 is 60:1) we scale the RHS using $c$ and $d$ found by solving these simultaneous equations
$$600 = c\log(30/1) + d = c + d(a + b_1d_1 + \cdots + b_n  d_n)$$
$$620 = c\log(60/1) + d = c + d(a + b_1d_1 + \cdots + b_n d_n)$$
you will get $c = 20/\log(2)$. Hence scaling the RHS by $c$ and $d$ will give you the scores you want. Hence we see that $20/\log(2)$ is just to achieve the 20 points to double odds mantra.
Answer: As for me all this theory wasn't that obvious I provide code with formulas to explain how all the "definitions" are translated into the resulting score.
<code>import pandas as pd
import numpy as np

df=pd.DataFrame()

df['fc']=[206, 205, 200, 220, 230, 235, 236, 240,250]
df['cat']=[0, 1, 0, 0, 0, 1, 1, 1,0]
df['good']=[0, 1, 0, 0, 1, 0, 1, 1,1]

train=df[['fc','cat']]
y=df['good']

from sklearn.linear_model import LogisticRegression

clf=LogisticRegression(fit_intercept=True, solver='lbfgs')
clf=clf.fit(train, y)

coefficients = np.append (clf.intercept_, clf.coef_)
print('Coefficients', coefficients)

#Option 1: Predict proba
test=pd.DataFrame (np.array([200,1]).reshape(1,2))
y_pred=clf.predict_proba(test)[:,1]
print('Predict proba: ' ,y_pred)

#Option 2: Calculate Probability
ln_odds=sum(np.multiply(coefficients,np.array([1,200,1]))) # sum(coefficients*values)=ln(odds)
odds=np.exp(ln_odds)
prob_good=odds/(1+odds)
print('Resulting probablity: ', prob_good)

#score from Siddiqi
pdo=20
factor=pdo/np.log(2)
offset=200

score1=offset+factor*np.log(1) #p_bad=0.5,   bad=good > odds=1
score2=offset+factor*np.log(2) #p_bad=0,3(3) good=2 bad=1
score3=offset+factor*np.log(4) #p_bad=0,2    good=4 bad=1
print(f'Difference 2 and 1: {score2-score1} \nDifference 3 and 2: {score3-score2}'  )

'''To calculate score from logregression '''
#NB! in regression target 1 should be set to good as in Siddiqi odds are 100:1 meaning 100 good and 1 bad
score=offset-factor*sum(np.multiply(coefficients,np.array([1,200,1])))
print(f'Score from regression:  {round(score,0)}')

#score from probability
score=offset+factor*np.log(prob_good/(1-prob_good))
print(f'Score from probability:  {round(score,0)}')
</code>


Raspberry Pi as a POS?

Question: How practical is it to use a raspberry pi for a POS system?  I'm in a small country where bring in a large quantity of POS system will cost too much. Was wondering if i can replace the current motherboard system of the outdated POS with a Raspberry pi and install windows xp.
Comment: You may be able to get it to replace your existing system, but you can not install Windows XP, nor should you as it is no longer supported.
Comment: Can you add pictures of the current POS system (hard- and software) to imgur.com and add the link to your question?
Answer: By POS I assume you mean Point of Sale System. There's no reason that you can't use the Raspberry Pi as a point of sale system, but you'd probably need to write such system yourself.
While it is a full fledged computer, there are some fundamental differences between the RPi and a standard desktop computer. The primary difference that will cause you problems is the architecture type. I went into some more detail about that on our blog.
In summary, programs compiled for a standard desktop or server system won't work on the RPi. You'll need a binary specifically compiled for the it. If you can find an open source system that you can compile yourself, or there's one in the repositories already, you're golden.
Answer: You certainly can use the RPI as a POS, and there are projects like Odoo (an open source ERP system) that do exactly that.
With the 7'' touch screen that was designed for the RPI, you could even have a nice touch screen interface for your POS at the cost of ~USD 120/seat for the RPI with the screen.
However, if your POS software is Windows only, than you are unlikely to benefit from the RPI for this deployment.
Answer: Try IotPOS: https://github.com/hiramvillarreal/iotpos
I am the developer and have been using it more than 2 years at grocery stores and restaurants.
Answer: ViewTouch offers Point of Sale on the Raspberry Pi under the GPL, also known as the Free Software License.  Visit http://www.viewtouch.com for all the details.
Comment: Welcome to Raspberry Pi! Please take the [tour](http://raspberrypi.stackexchange.com/tour) and visit the [helpcenter](http://raspberrypi.stackexchange.com/help) to see how things work here. Note that your answer *sounds* heavily like an advert (while it does not try to sell something - it's free software. It would also be advisable to provide some information whether it runs on the Pi's ARM-based architecture. Also: [full disclosure of your affiliation (if there is any)](http://meta.stackexchange.com/questions/15787/how-do-i-mention-my-own-products-in-answers) is required.
Comment: Yes, ViewTouch runs on the Raspberry Pi.  I had actually already said this.  [This is the GitHub link for ViewTouch](https://github.com/ViewTouch/viewtouch).  Disclosure: I am the person who holds the copyright on ViewTouch and who has been providing the financial resources for developing it from the day I first created it in 1978. There is a button on the [ViewTouch touchscreen desktop](http://www.viewtouch.com/desktop.html) which generates a new set of binary files from the sourcecode at GitHub.

Raspberry Pi as a POS?


Can I increase the bounty amount over time?

Question: Can people be able to increase the amount of bounty after they put the bounty on a question? If there isn't, I think it should be because when a question still stays unanswered after you put a bounty on it, you should be able to add more bounty to get the question answered more quickly. Isn't the objective of bounties inducing people to answer the questions? All in all, there should be a command to add more bounty to a question that has already been offered a bounty. Because, it would be time saving since you have to wait a week to offer more bounty on the question with this system.
Comment: makes sense to me. But I think the minimum amount of rep to add to the bounty would have to increase each time, otherwise people could game the system. Instead of a +300 bounty, they could successively add +50 to the bounty for six weeks. Or they could just add +50 to the bounty every week to keep a question hot forever and never award a bounty
Comment: So what you're basically proposing is a way for people to "feed the meter". Add extra rep to the bounty and this, in turn, lets the bounty stay open longer? Say, 7 days from the time you last added rep to the bounty
Comment: @Jim Yes, that is what I am proposing basically. It not only makes the bounty stay up longer but also adds more bounty to help the question gets answered more quickly.
Comment: But you should make this a feature request
Comment: @Jim Yes there should be regulations for stopping system abuse. And thanks for the suggestion.
Comment: This would be a network wide feature, so it should be discussed on the mother meta. I see that Jim found [just such a discussion](http://meta.stackexchange.com/q/203902/262980).
Comment: @dmckee I wasn't aware of that discussion. I am sorry. However, why this kind of system is not used and accepted since it seems like community liked the idea in that discussion?
Comment: @Starior It's no problem, it's just that opening a discussion like this on the physics meta isn't going to get very far: it'll have to be discussed on the mother meta anyway. As for why it hasn't been implemented, we have to assume that the team has given it a low priority because (1) +27/-4 is not a particularly strong vote; (2) it is not preventing users for performing core site features; and (3) they may want to let it stew awhile to so people have a chance to think up the abusive corner cases. The good news is that it has not been marked [status-declined] or even [status-deferred].
Comment: @dmckee Okay so since there is a discussion for this topic on mother meta I think this thread should be closed. Am I right?
Comment: I don't know if we have a policy on that.
Comment: What you should consider doing is posting an answer in support on the mother meta thread. That should revive the question
Answer: It seems we must have violated causality (only logical explanation) because almost a year ago someone posted a suspiciously similar feature request on the mother meta that includes the stuff we talked about.
It doesn't look like any mods really looked it over thoroughly and I didn't see many persuasive arguments against it. So with that in mind, I'd be for allowing people to feed-the-meter as long as protective measures like an increasing minimum rep payment is implemented. Perhaps also, the any rep from the bounty that is 7 days old should be treated like 7 day old bounties in the current system to prevent users from building up questions with 5000 rep bounties, which could effectively bypass the rep cap to let them do all sorts of things (get their friends to trusted status in a week, for example). Or there should be a maximum rep cap on bounties that's, say, 3X the current max rep.
But these are just ideas, I'm for it until I hear a good argument against it. The details can be worked out by people more motivated than I.


Estimation of Battery Life Time From PWM Signals in a Quadrotor

Question: Is there any way of estimation the battery life from pwm outputs which goes to motors in microcontroller level. I'm planning to estimate path range with this. Microcontroller, sensor and other electronic device should be neglected.
Answer: Battery life is generally measured in amp hours. From a PWM perspective, you are pulsing current at a constant voltage, so you could estimate current output to be (duty cycle)*(rated current) where rated current is the nominal current draw at your operating voltage. Remember too that P=IV, so you could get a rated current by dividing rated power by operating voltage.
So now that you have an estimate for current draw, you can do a simplistic state of charge estimate called "Coulomb counting", which is just current integration.
This means that you take your current and multiply it by whatever your sample time interval is, then add it to the previous measurement.
<code>spentCapacity = spentCapacity + (dutyCycle*maxCurrent)*dT
</code>
In this manner you accumulate how much current you have "spent" and can compare that to how much you started with.
This is not super accurate by any means, but if you're interested in a basic setup that will get you in the right ballpark this is it.
If you go this route, better current measurements are an easy way to improve accuracy, but Texas Instruments makes some "battery fuel gage" chips that are pretty slick too.
Comment: I'd just like to point out that you need to measure apples to apples. For comparisons, spentCapacity, your current multiplied by your sample time, should be in the same units that your battery capacity is in. The only exception to this might be if the conversion involves division, in which case I would suggest leaving spentCapacity in native units and only converting when you need to poll capacity.
Comment: So if current is measured in mA, but you're sample time is measured in *seconds*, then your spentCapacity is measured in mAs instead of the more common mAh. You could convert every sample to mAh with the following `spentCapacity = spentCapacity + (dutyCycle*maxCurrent)*dT/3600` but then you're dividing by 3600 every time you update spentCapacity (high frequency). Instead, divide by 3600 only when you poll spentCapacity (low frequency) and save yourself the computational cost of all that division.


License upgrade doesn't extend term of license?

Question: I just upgraded my license to Extra about a week and a half ago, so perhaps I'm supposed to know this.  The FCC database shows my upgrade to Extra, but the expiration date and callsign haven't changed.  I thought that my license would be renewed, at the very least.  Can someone shed some light on this?
Answer: Renewal, upgrade, and change of call sign are three separate things, except that renewal and change of call sign may be requested together.

§97.21   Application for a modified or renewed license grant.
(a) A person holding a valid amateur station license grant:
…
(2) May apply to the FCC for a modification of the operator/primary
  station license grant to show a higher operator class. …
(3) May apply to the FCC for renewal of the license grant for another
  term in accordance with §§1.913 and 1.949 of this chapter. …

As to your callsign,

(c) Except as provided in paragraph (a)(3) of this section, a call sign obtained under the sequential or vanity call sign system will be reassigned to the station upon renewal or modification of a station license.

I vaguely recall that you can ask the VEs to get you assigned a new sequential call sign when they submit the upgrade on your behalf, but I'm not sure about that.
What you can do now: you can apply for modification of your license, or if within 90 days of expiration, a combined renewal and modification, which may either:

Request that you be assigned a new sequential call sign, which will be from the series for Extra class operators, or
Request a vanity call sign chosen by you (subject to the restrictions on vanity call signs).

For details on this process, see Form 605 (PDF), which is the form for all license renewals and modifications, and Schedule D in the same document, which is abut amateur radio call signs in particular. (When you actually go to make the request, you would usually do it through the FCC ULS, not by filling out this form on paper.)
Answer: Unless your license was set to expire within the next 90 days, it won't be renewed.
From the back of NCVEC 605 or numerous times on FCC 605:

License renewals (with associated fee for vanity renewals) may only be
  completed during the final 90 days prior to license expiration, or up
  to two years after expiration.

As for your callsign, if the box labeled "CHANGE my station call sign systematically" was left blank, your callsign would remain the same.
N2KIQ
Answer: If I am not mistaken, I believe a license is good for 8 years.  So when a class of license is upgraded, the expiration date should remain intact.  Congratulations on your extra class license.
Comment: Hi Mel, and welcome to hamSE! :-) Perhaps it has changed, but our licenses in this household are good for 10 years. They were issued in March 2011 and expire in 2021.


To say something in choir word

Question: This word, or expression has been bugging me. I think it's "to say something in choir", though I'm not sure, and everything I get from searching the internet is videos of choirs singing. The expression I'm looking for is someone saying something at the exact time. Doesn't need to be intentional, just that someone responded at the exact same time. The sentence "to say something in choir" is directly translated from the expression in Norwegian, as that is my original language. "To say something in symphony" might be it. Though, this has nothing to do with music. Simply two (or more) people who are saying something simultaneously.
Comment: Another phrase for this is "in unison".
Comment: So it would be formulated as: "Good morning", they said in unison. ?
Comment: Yes, that's correct.
Answer: I think this is actually in chorus. See the second example here:

chorus

A simultaneous utterance of something by many people.
a growing chorus of complaint
  "Good morning," we replied in chorus

Oxford
Comment: Ah, thank you very much. I had a feeling choir was the wrong word :D
Comment: It's also a verb with a similar meaning, "chorused". eg: `"Good morning, class," Miss Frizzle said. "Good morning, ma'am," the students chorused in response.`
Answer: I believe Andrew's answer was spot-on.
Here is one more suggestion:
In unison.
At the same time; simultaneously.
Origin: from Latin uni- "one" + sonus "sound".
Answer: There is another, rather more esoteric, answer: "in concert". It's more poetic, less likely in everyday speech, and it means "intentionally acting together so as to have some effect".
By contrast, "in unison" need not have intention: two people may accidentally speak in unison, but they can't accidentally speak in concert or in chorus.
"In chorus" need not carry the idea of aiming to carry out a goal. Several people may speak "in chorus" (for example, the unison greeting of a class to their teacher), but to speak "in concert" there must additionally be some reason why speaking together is necessary to achieve something.
Two people may speak "in concert" if they have arranged to speak at the same time for added effect, for example. It doesn't often refer to speech, but more usually to an action of some kind.
Comment: Thanks for the differentiation between the different words. I didn't know about "in concert", nor that there is a word for speaking in unison with intention to do so.
Comment: "In concert" is also used to mean "performing music in a concert", that is, before an audience. Weirdly a solo musician performing unaccompanied can be spoken of as being "in concert".
Answer: Most likely not the answer you're looking for, but one that most children will be aware of is:
jinx
A jinx occurs when two people say the same words, in unison accidentally.  The first person to say 'jinx!' following the occurrence has jinxed the other person who is then not allowed to speak until someone says their name.
Of course, if both people who spoke the first in unison sentence know the game, they are both likely to say 'jinx' at the same time as well.  Depending on the variant, the procedure then is to say 'double jinx' (followed by 'triple jinx', 'quadruple jinx', 'jinx infinity' or similar progression), or count to ten out loud and then say it again.  This invariably leads to an extended sequence of two people saying what appear to be random words in concert.
EDIT: Oops, as @AndrewT mentions, the general use of the word 'jinx' is to cause bad luck or unfortunate circumstances on another: you may need to provide extra disambiguation when using it.
Comment: @AndrewT.: That's a completely different meaning, and highly unlikely to cause confusion.
Comment: Just be careful with the usage though, since in general it's considered as [bad luck](https://dictionary.cambridge.org/dictionary/english/jinx).

To say something in choir word


Show that every definite language is accepted by a finite automaton

Question: A language $L$ is definite if there is some $k> 0$ such that for any string $w$, whether $w \in L$ depends on the last $k$ symbols of $w$. How can I prove that every definite language is accepted by a finite automaton?
Answer: This is true as a consequence of the Myhill Nerode theorem. For any fixed $k\gt 0$, the number of possible combinations of the last $k$ symbols of any string $w\in L$ is $|\Sigma|^k$, where $\Sigma$ is the alphabet.
Any two strings that have the last $k$ symbols identical will always be both accepted or both rejected by $L$, for any string appended to them, i.e., no string in $\Sigma^*$ will distinguish such strings. Thus, such strings lie in the same equivalence class of $L$.
Strings with differences in their last $k$ symbols will either lie in different equivalence classes or will cause the classes demarcated in the previous step to collapse together into a single class.
Thus, the equivalence classes of $L$ are determined by the last $k$ symbols of $L$.
As the possible combinations of the last $k$ symbols is finite, the number of equivalence classes is finite. Thus, by the Myhill Nerode theorem, the language $L$ is regular. Hence, there exists a DFA that accepts $L$.
Answer: Hint 1:

 $L=L_1\sqcup L_2$ where $L_1=\{u \in L : |u|<k\}$ and $L_2=\{u \in L : |u|\ge k\}$.

-

 What properties would you like to have on $L_1$ and $L_2$ to prove that $L$ is regular?

Hint 2:

 What property does $L_1$ have that makes it regular?

-

 How many elements are there in $L_1$?

Hint 3:

If $u\in L_2$, then $u$ can be written $u=vw$ with $|w| = k$.

-

 And then $\Sigma^*w\subseteq L_2$.

-

 Take $L_3=L_2\cap \Sigma^k$.

-

 Express $L_2$ in terms of $L_3$.

-

 $L_2=\Sigma^*L_3$

Hint 4:

 What property does $L_3$ have that makes it regular?

-

 How many elements are there in $L_3$?


Excess baggage to Kenya from Geneva

Question: Apart from the 30 kgs offered by Qatar Airways, I have 10 kgs that I  will take with me. Is it possible to take these extra kilos in a second bag?
Comment: How is upgrading to business  done ? I mean how does it work ?
Comment: upgrading to business is expensive, and tickets bought in promotion cannot be changed or upgraded.
Answer: Airlines, including Qatari Airways, offer an excess baggage service, but it can be expensive.
Qatari Airways charge $50/kg for excess baggage from Europe to Africa ($40/kg if bought online ahead of time), although for flights to Africa you can get a bulk rate of $50/5kg (source:Qatari Airways)
Other charges may apply if your itinerary includes flights with other airlines, and the bulk rate is not available from all airports.
The Qatari web site suggests you call them to verify the rules and charges applying to your flights, although they say that if you have already booked a flight you should be able to buy excess baggage online.
Comment: Often a upgrade to business is a cheaper option.
Answer: Normally, both the option of paying extra weight or upgrading to business class can be costly.
There is usually a third option, if you have time, and things are properly planned. Carry it as cargo, as it is significantly cheaper. You pack it on boxes, and you carry it to the airport before the flight. It could be the day before, details vary from airline to airline, check with them.
If things are properly planned, the cargo will arrive in the same plane as you, otherwise it might mean going to the airport again to pick up the cargo. (I think it is the bulk rate the other answer is mentioning, I just noticed it now)
However, you would better check better the details of you travel package/tickets. If I am not wrong, you are allowed to carry 30kg + 7kg in your hand luggage that you take to the plane with you.
So at the end of the day, we are just talking about 3kg in excess. Even less if you are willing to trade sandals/sneakers for ticker boots or take an heavier coat to the cabin.

Hand Baggage allowance
In addition to the regular checked-in baggage allowance you may carry, you may also bring along hand baggage on board the cabin during your Qatar Airways flight:
Economy Class customers are allowed to carry one piece of baggage, not
  to exceed 7kg

On top of the hand luggage, ladies often also carry their purse, and men their computer.
With a bit of luck you might not pay more to bring the extra 10kg, except if officials are being more strict in a very packed flight.
In a similar situation, I brought 11kg in my hand luggage from Africa without being extra charged, however I do not endorse trying to do it.
Comment: Can those 30 kgs be split into two  suitcases, for example 15 kgs in each or it has to be absolutely one piece of 30kgs( still on qatar airways economy class from Europe to Kenya) I  have a problem  lifting heavy weight.
Comment: Their official position is that the 30kg can be divided in two *or more bags*.

Excess baggage to Kenya from Geneva


Traveling from Russia in 1906

Question: My Great Grandma had to leave Russia when she was just 16, and travel to England. I know the ship she took from England to America, but I don't know how she got to England. Would it have been the same ship?
Comment: If it was a commercial passenger ship, almost certainly not.
Answer: When you say you know the ship, do you mean you know the ship's name or have you seen the passenger list (image)?
The passenger list page headers in that period should have originating port information. It may show that that ship's voyage started in England or it may show another European country, not necessarily Russia. It is possible that your ancestor made her way to Germany or Scandinavia or even further, overland (trains) or by sea (even multiple short trips, but most likely just 1).
If her voyage originated in England or she got on board in England, it is possible that she stayed in England longer than just the time to change ships.
There may also be pages that the start of the transatlantic voyage's record with general information. Researching the ship may tell you its usual ports-of-call.
Note that "local" passenger lists (from Europe to England) were usually not retained.
Answer: As per https://genealogy.stackexchange.com/a/15574/6485, European emigrants to America via England usually landed at an East Coast port (most often Hull or Dover) and took a train to a West Coast port (e.g Liverpool) to take a ship to America.
So it is unlikely that your Great Grandma stayed on the same ship throughout, and you should follow the advice on the linked answer.
Comment: Hey, that's *my* post! :-)  I was planning on adding a link to that here, but you beat me to it.
Comment: My grandparents travelled in 1953 on the "Columbia" from Bremerhaven Germany to Southampton England to Cherbourg France to Quebec Canada. Admittedly later than the OP's ancestor, but probably not a unique voyage.

Traveling from Russia in 1906


Refund for foreign purchase is less than amount spent. Will credit card company refund difference?

Question: I recently made a credit card purchase at a Japanese shopping website. When I looked at my statement, the amount was in dollars (converted from Japanese yen). Later, I cancelled my order and was refunded the same amount in yen, but because of the exchange rate, the amount (in dollars) I was refunded (-$10) is less than the amount (in dollars) I spent ($12). Both transactions appear on my statement. Will my credit card company refund me the difference ($2) if I ask?
Comment: If they refund that, there would be a way to get rich fast - Buy and cancel, buy and cancel, etc. every win is yours, every loss is reimbursed... it would be riskless currency trading. It can't work.
Comment: I don't think there's any way to know without asking them.  That said, I wouldn't expect them to.
Comment: Would you be happy if, had the rate drifted the other direction, they captured the profit? It's both of nothing, and it's easier for everyone if the credit card company just moves the money without trying to compensate for it speculate upon rate shifts.
Answer: Generally as a good will the card company may give you the credit for 2usd.
There is no harm in trying.
Comment: Just that $2 is really not enough to even bother, see related questions. :-)
Answer: My opinion is not likely. You entered a transaction where you purchased yen with your dollars, then used the yen to purchase the items. Later, when  canceling the order, the yen transaction purchased dollars. Foreign currency prices change constantly. The credit card company (bank) isn't responsible for the difference in price changes between currencies. If you were to cross the border to another country (say Mexico, Canada), attempt to purchase an item with USD, the vendor MAY accept your USD at a specific exchange rate for that day. Were you to re-visit the next day and return the item, a different exchange rate would be in effect and you would be refunded accordingly.
Comment: Many credit cards also tack on a 3% foreign transaction fee on the amount of the purchase. In the best of all possible worlds, the OP will be charged the 3% on the difference between the purchase price and the return price. Possibly, the fee will charged only on the purchase price and not on the return price, but I wouldn't be surprised if the fee is charged both on the purchase as well as the return. After all, both are "foreign currency transactions" even though one is a debit and one a credit to the credit card company.
Comment: Good point- of course there are fees, not to mention spreads (buy/sell), etc.


Design decision for a cross-platform text editor that optimized for speed

Question: On designing a cross-platform text editor that optimized for speed - I heard atom.io uses node.js, would it be slow? I heard sublime text uses C++, would it lots of effort to be cross platform and make GUI? I am trying to find out  some of the best ways of achieving performance, cross-platform, easiness of making GUI and good maintainability.
Comment: @HighPerformanceMark I generally agree with that, though I've personally been frustrated with Electron app performance on low-end machines. Sublime scales much better on large files thanks to its lower memory overhead for being written in C++
Comment: Given that a text editor is almost certainly going to have a human in the loop I wouldn't make speed a critical factor in selecting a programming language to use.  I'd probably not make it a factor at all.
Comment: Fast, good, cheap: pick two
Comment: you'll need to select you target platform/hardware range, the expected file size, the expected overhead (coloring, structure parsing/visualisation) and benchmark. For "small" and "simple" files Electron may suffice, but without clear latency goal and target conditions/constraints range nobody can answer that question for you.
Answer: Atom, VS Code, and Electron apps more generally trade a lot of development time for CPU cycles and memory on the end user's system. I've found both aforementioned editors quite sluggish on low to mid tier laptops, and they aren't particularly kind to the battery, either.
Still, they perform acceptably well on developer workstations and people generally like to use them, so they must be efficient enough for the business purpose.
From a software standpoint, editor response times rely on a large number of factors and scale with the number of modules that need to know about each keystroke. If you want to perform syntax highlighting, code completion, automatic indentation, integrate static analysis, etc. then it will be important to keep the UI thread IO bound. It should spend almost all of its time waiting on the user to do something. Architecting the rest of the editor to move compute bound tasks to worker threads that can asynchronously report their results to the UI will be most important. I also want to specifically call out the importance of having a good strategy for re-parsing modified text. It should scale with the amount of text that was changed, rather than the length of the document (as it would if you re-ran the parser on every keystroke)
Those concerns will dominate the perceived performance of your editor much more than the language you write it in.


Postponing driver's license renewal

Question: I am 76 years old. I have a California driver's license expiring on September 8, 2018 and presently live in Europe. I cannot be in CA on the renewal date. I probably will be in the US in spring 2019. Can I do it at that point?
Comment: By "CA" do you mean "California" (for which CA is the standard state abbreviation), or "Canada" (for which CA is the ISO two-letter country code)
Comment: @MartinBonner since Canada doesn't normally issue driver's licenses, it's probably safe to assume that CA is California in this case.
Comment: @phoog - Ah, they are issued by the province.
Comment: If you "reside" in Europe, are you even eligible by CA law to hold a CA driver's license?
Comment: Be careful.  Since you are not a California resident at the moment, you may not be eligible to renew a California license.  (That is certainly true of my jurisdiction, Saskatchewan, and we would allow you to get a new license here again within five years of the expiration of your old one, or if we offered reciprocity with the country where you carried your European license.  California may, of course, vary.)
Answer: If this is a California license, according to  this private website you can renew it up to six months before it expires or 90 days after it expires (so December 7th 2018).  After that you would have to apply for a new license.  According to my searches, the DMV agent may choose to waive the requirement for a driving test - but they don't have to (and may have a prejudice against allowing a more mature person on the road).
Note that if you are living in Europe, you probably can't drive with the US license after a certain number of months.  (The period will depend on precisely where you are, but a year is typical.)
Comment: Not sure that the second part of your answer is accurate... my experience has been that if you remain within a single country for 12 months, then you are expected to get a valid local license, but if you leave that country periodically (perhaps go to a different European country) the 12 month clock is "reset".
Comment: @Seamus The clock will be reset if you move home.  Just going for a holiday won't reset the clock.  The question is "where do you reside?", not "where did you sleep last night".  Most people do not move home every year (but there are some that do).
Comment: That will depend on how long the "holiday" is! It's all quite variable, and dependent upon a number of factors. These things are far from "settled", "well known", "common knowledge" and "uniform practice". Thus, my comment, and I shall stand by it.
Answer: Since California driver's licenses can be renewed online, your temporary absence from the state shouldn't prevent you from renewing before it expires.
If you received the renewal notice by mail in California, you may have other options such as renewing by telephone following its instructions.
Comment: Read the question more carefully.  You can only renew online if you are under 70.  The OP isn't.  See https://www.dmv.ca.gov/portal/dmv/detail/online/dlrbi/dlfaqsmain#eligible (second bullet).

Postponing driver's license renewal


What direction should a traffic pattern be at an uncontrolled or non-towered airport?

Question: What is the standard direction for a traffic pattern at an uncontrolled or non-towered airport?
Comment: I disagree that it's a duplicate. This question simply asks which direction that traffic patterns should be flown. The other question asks if it's okay to fly a straight-in approach. They have a similar answer derived from the same regulation, but it's not a duplicate.
Comment: possible duplicate of [Traffic pattern required with no traffic at untowered airport?](http://aviation.stackexchange.com/questions/622/traffic-pattern-required-with-no-traffic-at-untowered-airport)
Answer: When aviation literature mentions "the standard traffic pattern", it's usually a left-hand counterclockwise pattern; regardless of wind direction, the runway will always be to your left side and you make left turns to follow the pattern through crosswind, downwind and base legs. This is the default pattern direction when there are no overriding signals.
However, this is only the default, and airports are free to change the procedure as needed to comply with local terrain or development. An airfield near a neighborhood to its east, for instance, may require that traffic circle around the west side of the airport; therefore this airfield's 17/35 runway will require a left-hand pattern when using runway 35, but a right-hand pattern when using runway 17.
When an airfield establishes a non-default traffic pattern, they must provide this information to pilots in a readily-visible manner. The standard recommended (though not required) set of runway and pattern indicators is known as the segmented circle, so called because its most visible identifying feature from a distance is a 75-foot circle of dashed lines:

In the center of the circle as pictured is the runway direction indicator aka the tetrahedron; this will indicate which strip of asphalt to use and which direction to take off and land on it (the narrow end points in the direction that planes should take off and land).
Off to one side is the windsock, which is the only piece of equipment that is required at any airfield; it indicates approximate wind speed and direction. FAA guidelines for the sock say it should reliably turn to the wind direction at 3 knots, begin to inflate at 5 knots and be fully extended at 15. The windsock can replace the tetrahedron in the center of the circle; in that configuration you would simply approach the airfield using the runway closest to the direction in which the tip of the windsock is pointing (if winds are calm and/or the airfield has multiple runways, the tetrahedron is preferable).
On the ground just outside the segmented circle are L shapes; these are the pattern indicators, and point in the direction of the base leg when approaching the runway from that end (so if you're following the pattern, the end of the L should be pointing at you before your turn to final).

So, the circle in the above picture tells aviators several critical things without any human (or computer) having to relay the information vocally:

The approach direction is from the upper right to the lower left of this picture.
The wind is roughly in line with the runway, so no crosswind landing procedure is required.
Winds are very strong (the windsock is fully extended which indicates wind speeds in excess of 15 knots) so ground speed will be much lower than IAS at takeoff and landing.
Most relevant to your question, airfield traffic should be on a right-hand pattern at this time; if the winds and thus the runway in use were opposite, traffic would use a left-hand approach.
Comment: IDK about a wind sock being required.  I've landed at a number of strips in the western US that didn't seem to have one.
Answer: FAR 91.126(b)(1) states that all turns in the vicinity of an airport in Class G airspace should be made to the left unless otherwise marked. That includes the traffic pattern.
Comment: That's not quite what it says: turns to the left "when approaching to land".
Answer: FAA Advisory Circular 90-66b
Title: Non-Towered Airport Flight Operations
3/13/2018

9.1 Left Traffic. Use of standard traffic patterns (left turns) for all aircraft and CTAF procedures by radio-equipped aircraft are
  required at all airports without operating control towers unless
  indicated otherwise by visual markings, light gun signals, airport
  publications, or published approach procedure. It is recognized that
  other traffic patterns (right turns) may already be in common use at
  some airports or that special circumstances or conditions exist that
  may prevent use of the standard traffic pattern. Right-hand patterns
  are noted at airports on an aeronautical chart with an "RP" designator
  and the applicable runway next to the airport symbol.


Display Jalali (Shamsi) Date in Archive View

Question: I have a Persian language website and I need to a archive block in my site.
but date of default archive view is Gregorian. I install Datex module and it convert all date of nodes to Jalali(Shamsi) Date but can't convert Gregorian date to Jalali Date in archive view.
I want to archive content in year+month format.
any one has another idea for convert date in archive view?
Answer: you can use of persoanTools module
persian Tools change calender to jalali and you can use of it in archive and views pages
Answer: to display jalali date in drupal, you can do one of the following :

install persian tools and Calendar Systems and in node.tpl file write the following:

<time datetime="<?php print date('Y-m-d H:i:s', $node->created) ?>"><?php print $date ?></time>

get timestamp from php, convert it to javascript timestamp and display it using toLocalDateString():

<time datetime="<?php print date('Y-m-d H:i:s', $node->created); ?>">

</time>


Basic question on S=I

Question: Consider the identity:
$$
Y=C+I+G+X-M
$$
 where $Y$ is defined either as value-added output, or income, or
total expenditure. Now, consider private individuals, who decide to
save money, as opposed to spending it. Aggregate demand decreases,
and so output follows, due to the Keyensian cross logic. However,
income that is not consumed, is saved. If savings increase, so does
investment. As such, why is it not the case that if consumption goes
down, investment goes up by the same amount? And if so, aggregate
output should remain unchanged, regardless of the decision of the
consumers after they receive their income?
Answer: The reason for that is that if you check carefully the model an important assumption is that investment is fixed $I=\bar{I}$ once you relax this assumption and allow $I$ be some variable function of interest the paradox of thrift disappears in long run.
This does not meant that fixing $I$ in the short run is incorrect assumptions as during recession you will get liquidity trap in a short run. Banks are scared to borrow money because they can't distinguish good lenders from bad. So in short run all the excess savings during recession get absorbed into banks hoarding liquidity and no matter how much you save $I$ is fixed. Even without recession another way of thinking about it is that in short run it's hard for companies to change their investment profile.
However, in long run once the $I$ is some variable function of interest rate and of course it has to equal public and private saving  $I=S+ T-G$ the paradox of thrift disappears ($I=S$ only if you assume government runs balanced budget $T=G$ which is fine but I wanted to point out that you should not forget about public saving).
Also I basically took the answer to this one from Blanchard et al. Macroeconomics an European Perspective. If you want to understand this deeper I really recommend checking the book, it's in my opinion the best undergraduate macro book on the market. If you google hard enough you can even find a free pdf version...

Basic question on S=I


Climate in an ice age

Question: Creating a map of Koppen climate zones for a very Earth-like world is quite easy, with the right instructions. However, what if the climate is several degrees cooler? Do I simply shift all the climates equator-ward, or is it more complex than that? If not, how much should I squish them?
Comment: Wikipedia to the rescue: [Last glacial maximum vegetation map](https://en.wikipedia.org/wiki/Last_Glacial_Maximum#/media/File:Last_Glacial_Maximum_Vegetation_Map.svg) (and [related article](https://en.wikipedia.org/wiki/Last_Glacial_Maximum)). Not quite what you're after, but an excellent start, I'd say.
Comment: @StarfishPrime Mm, that would make sense, as the continents would expand and the water cycle would be slowed down due to less evaporation. Pity the map doesn't use the Koppen system, but thanks for sharing.
Comment: It gets drier, too. Someone posted a picture of climate zones during an ice age quite recently... I'll see if I can find it, or if they left a source. Or maybe they'll be along themselves soon enough...
Comment: @SealBoi  Yes. Sea level on Earth went down some 100's of feet. Also, under all that ice the elevation of ground was significantly different because 2 km of ice will depress even rock after a few 1000 years. There are lovely beaches in northern Canada that are still rebounding.  https://en.wikipedia.org/wiki/Post-glacial_rebound
Comment: Features like the subtropical ridges wouldn't move as they're a product of the atmospheric cells, however due to increased aridity, the desert bands where these ridges lie would be wider than they are on present day Earth. Another consequence of cooler temperatures is decreased evaporation however, so those regions aren't necessarily desert, but could rather be dry steppe with quite a lot of biomass.
Answer: Ice Age Climate
Climates and Geography
While there are situations where shifting equator-ward (and colder climates shift downward with altitude too remember) may not be the precisely right answer, that is generally the case so long as you remember a few points

colder weather may change currents that would bring different weather fronts which would change temperature in specific regions (Europe is warmed by mid-Atlantic current for its latitude. If Ice Age shifted that current Europe would be much colder even if the average temperatures elsewhere were less shifted). Currents are also shaped by the continents around which they move water.
shifting rain bands make different areas deserts that get much hotter especially with the right types of soils and bedrocks (see shifting rain bands and the Sahara moving north and south in Africa)
the koppen system fixates on latitude/elevation, precipitation levels, season where majority of precipitation is received, summer temperatures, etc. Other systems for classifying climates exist, focus on other factors in varying emphasis and leave out others. Different models have different strengths and weaknesses and the science as a whole is not fully grasped as the factors that could effect this system seem to still perplex the people predicting the weather.
science here will change as we improve our knowledge. Fixating on accuracy in arbitrary circumstances such as providing accurate climate maps with this world will make the work more quickly dated. Quality content within the setting while leaving the setting more ambiguous such as mentioning of the Ice Age without Koppen acronym might be a better approach for the narrative happening within it.

There are a lot more examples and things to remember to consider, but the key is not the specific accuracy of any specific climate maps unless you are specifically making maps of hypothetical worlds guaranteeing climate accuracy in their Koppen zoning.
The goal should probably be to produce quality content in the setting While your setting may not be totally accurate, it would behoove you to make sure it is not so inaccurate as to be glaringly obvious while also not specific enough to be easily dated in 5 years. Depending on what the prose is for of course...

Climate in an ice age


staking tomato plants

Question: How can I stake tomato limbs after they have been growing on the ground and heavy? I have most of the plant in a cage but some escaped and when I try to put it in the cage, it breaks. I am a new gardener!
Answer: An already established plant is often set in its ways and the old growth is best left alone. However the new growth is soft and amenable to new training. Figure out a suitable support based on the new growth, even if it is only a stiff stake pushed into the ground at each growing point and tie in/train new growth up the stake to keep it off the ground. The old stuff can stay where it is; make the best of any fruit down there, maybe on a bed of straw, harvest early to avoid slug damage and allow the old stems to root along their length. This will strengthen the new growth and enhance the possibility of new clean fruit to come.
Answer: Without a picture it is difficult to advise.
You need to tie the vines to the cage.
Below are some images of vine ties. I am not recommending these products they are to give you an idea.  You can use twine or thin rope also.
For more ideas watch some videos on the topic:  YouTube "Tomato ties" search
You can use a combination of ties and string.  Put a tie around the vine then tie the string to the tie. Then tie other end of the string to the cage (or anything above the plant). A strip of cloth (1-2" x 8-12") can be used as a sling in place of a tie for heavier vines.
I do not use a cage.  I just tie the vine to a stake.
I use furring strips for a stake: Furring Strip

staking tomato plants


Multiple serial monitors with the same arduino mega

Question: I've got mega 2560.
In my project serial port is used for communicating with PC.
However, I'd like to see debug info in serial monitor. Mega has a few hardware Serial ports. How to use one of them got extra serial monitor?
Answer: Use an USB to TTL Serial adapter. Wire it to one of the RX/TX pin pairs and in code use the corresponding Serial object Serial1, Serial2 or Serial3. Don't forget to wire Ground.
You can use some terminal program or Serial Monitor in Arduino IDE to communicate over the adapter. You can open a second instance of the Arduino IDE by starting it with the Desktop or menu shortcut. In this instance you can select a different port then the sketch upload port.
Comment: https://arduino.stackexchange.com/questions/57653/can-i-have-two-separated-serial-monitor-for-the-same-arduino-board-connected-to/57669
Answer: You need to connect one (or more) to your PC. To do that you would use a USB to TTL UART adaptor, like an FT232 board.
That will give you a new COM port that you can open with your terminal program of choice, though opening the Arduino "serial monitor" multiple times might be somewhat difficult.


Reading Analog values of bluetooth module HC 05

Question: I am working on a project which requires signal strength of a bluetooth TX and RX. what i assume is that in bluetooth module like hc05, there is an antenna receiver which reads the analog signal and then passes it to its ADC to get data in terms of 0's and 1's. But is there any way i can read the analog signal strength of the reveiver antenna directly? Please help
Comment: Start by getting the data sheet for the HC05 and reading up on how it works. If anybody has written drivers for the HC05 you may also find useful information there.
Answer: Try looking up the datasheet to see if there is a command for signal strength. It's impossible to directly read the the analog value since the signal strength is way too low in amplitude.


Minimum Processor Requirements to set up Openstack on a Laptop/Desktop(not for Devstack setup)

Question: I am planning to do a POC and setting up OpenStack in nonCommercial setup.I do not want to go with Devstack.I am confused as to how much is the minimum processor requirement if i plan to setup openstack on a Laptop (having single VM instance).Can i Use a quadcore processor or do i need to have a dual quadcore.My intention is i do not want to procure a ne server unless it is actually required.I want to rather check if i can use any other existing laptop and get the work done.Really appreciate an answer with the specifications.
Answer: Depends on what you are doing.
OpenStack supports multiple virtualization / container solutions.
It's original support was libvirt which meant KVM / Qemu.
If you want to do any sort of hypervisor virtualization ( IE vmware esx, kvm, xen ) you will need a CPU that has virtualization extensions ( Intel VT or AMD-V ).  This can be seen in /proc/cpuinfo as 'vmx'.  Note that this usually needs to be enabled in bios.
However, if you are emulating as with qemu without kvm... anything will do.  Usually the limiting factor in virtualization isn't CPU, it's ram.  You will probably want a server with as much ram as you can afford to stuff in.
All this being said... there's another newer solution.  Docker.  Or more appropriately, LXC.  AKA Linux Containers.  OpenStack now supports deploying Docker style linux containers.
What this gets you isn't really a VM... so much as the ability to replicate a seperate instance of your HOST OS.  So if you are on ubuntu 12.04... you can spin up a bunch of isolated 12.04 linux instances and do whatever you want to them without impacting the host.  The benefit here is you don't need VT extensions, and you don't need to really virtualize at all.  It's pretty snappy.
So, what's your intended use profile?


JustMock and nCrunch

Question: I am getting the following error message:
The type or namespace name 'Telerik' could not be found (are you missing a using directive or an assembly reference?)
I added Just Mock to my testing project and I followed the configuration instructions at
http://www.telerik.com/help/justmock/integration-ncrunch.html
All I did was add the Proxy file path to on my test project in the ncrunch configuration : C:\Program Files (x86)\Telerik\JustMock\Libraries\JustMockRunner.exe
Did I miss something?
Answer: This is usually caused by having installed ngen'd assemblies for the /Profile scenario. Some profiler-based tools do that upon installation to speed up their loading.
The fix is to uninstall all /Profile assemblies from the GAC, by executing the following command in an elevated command prompt:
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\ngen.exe uninstall * /profile
Adjust the framework version and bitness to match the .NET version installed on your machine.
If you see messages like Uninstalled assembly mscorlib. then you know that was the case.
The entire operation is also explained in the Troubleshooting section of the JustMock documentation.
Answer: I think this is because the Telerik.JustMock.dll isn't in the GAC, which is why when you add the reference you point it at the JustMock Libraries folder. Just add the Telerik.JustMock.dll in the Additional Files To Include option in NCrunch for your test projects.

JustMock and nCrunch


What does the pond do?

Question: I was at the lollipop farm, when all of a sudden, an option for me to "dig a pond" pops up. I don't want to waste 100,000 candies for no apparent reason, so can anyone tell me what it does?
Answer: The pond allows you to buy Lolligators for 1200 candies each. Lolligators can be fed candies, turning them into lollipops at a 1:1 ratio.
It's useful if you have a large amount of candies and want more lollipops instead.
Answer: The pond, when bought, allows you to buy "Lolligators," or alligators who eat your candies in exchange for lollipops.
Answer: The alligators when you buy the pond they cost 1200 candies you feed them candies if you have a lot and want lollipops instead you feed them and get lollipops in exchange for the candies

What does the pond do?


Air Conditioner turns on when turning on the front defrost 1999 Olds Aurora

Question: I have a 1999 Olds Aurora and when I turn the front defrost the Air Conditioner turns on and I can't turn it off. Is that what I want to happen? It doesn't do that on my other 2 cars.  How can I fix that?
Comment: Welcome to Motor Vehicle Maintenance & Repair!
Answer: This is actually typical in many different vehicles. The idea is, when the defroster is on, the A/C kicks on to take the humidity out of the air, which then gets blown onto the windscreen, which dries it out allowing it to defog quicker. Some cars are setup like this while others aren't.
This really isn't a bad thing, for two reasons:

It keeps the A/C parts moving and lubed during times when you wouldn't normally be using them.
As stated, it clears the inside of the windscreen faster.

Bottom line is: It's this way by design.
Comment: Yep.. this is extremely common and by design. My current and previous two daily drivers both did this.


BTC to BTC trades on Ripple

Question: I see some BTC to BTC trades on Ripple.
Are these just transfers from one exchange to another?
Or, is Ripple being used as a mixer?
Comment: Are we talking Bitcoin to Bitcoin or Bitcoin-IOU to Bitcoin-IOU (or some remix thereof)?
Answer: The counter-parties are different.
In Ripple chain: BTC has an issuer, it can be Bitstamp, Snapswap, Gatehub or any other gateway. So if you send your BTC to Bitstamp, they will give you BTC (issued by Bitstamp), if you send BTC to GateHub, you will get BTC (issued by Gatehub).
If you have BTC (SnapSwap) and you want to withdraw BTC from your Bitstamp account, BTC must be exchanged from BTC Snapswap to BTC Bitstamp. Though it can be done automatically (path can be found)

BTC to BTC trades on Ripple


Usage of こいつ, あいつ, etc

Question: When can I use こいつ, あいつ, etc?
I've seen that they can mean he/she/this/that in various contexts but when is it appropriate to use them versus 彼 or 彼女?
Answer: Roughly speaking, こいつ, そいつ, and あいつ mean "this/that guy", except they're gender neutral. Essentially, they're colloquial, and slightly rude, variants of この人, その人, and あの人, which mean "this/that person".
彼【かれ】 and 彼女【かのじょ】 are equivalent to the English "he" and "she" respectively, but they're relatively distancing words; they generally carry the connotation of "that man/woman over there" or "this man/woman neither of us know well". In most conversations, if it's clear from context who you're talking about, you can just drop the pronouns completely, but if it's not clear but both of you know the person by name, just use their name + さん/くん/ちゃん and you're good to go.
Hope that clears it up :>
Answer: If I am not mistaken, one thing to add to Ranquil's answer is that 彼 and 彼女 can have the respective meaning of "boyfriend" and "girlfriend", something never conveyed through the series こいつ, そいつ, and あいつ.

Usage of こいつ, あいつ, etc


Complete question timeline including votes

Question: Is there any chance to get more information in questions timeline such as when it has been upvoted, when it has been downvoted, same for all answers, including comments, and other actions such as vote for close and so on?
Answer: Voting data will never be exposed (as a stream anyway) with great accuracy, as its too easy to correlate it with user activity*.
Easier streaming of site updates (questions, answers, comments, edits, etc.) is something I'm considering for the next version, though.
*Provided some minimum amount of traffic to the site, anonymity is more or less guarantee-able if we scrub voting data.
Comment: Good point. I think that what I want to build must be server-side for that exact reason.


Thumb ring and index finger

Question: I have a new bike for 3 month and after about 20 Km my ring and index finger on the left hand became numb. Just as an information for my hand position: These fingers are always on the brakes. Here is my handlebar and brake lever position. Any idea how to adjust them to get rid of this problem?
Comment: "These fingers are always on the brakes."  That's your problem.  You've got to move your hands around.
Comment: Personally I prefer the trailling bulge of the grip to be a lot higher, to provide palm support.  But with those ones the barend might be integrated so raising one lowers the other ?
Comment: Silly clarification - from stem outwards, my digits are thumb, index finger, middle (long) finger, ring finger, little finger.   Do you really have your index and ring finger on the brake and your middle/long finger around the handlebar?  That sounds horrible!   Try with just your index finger on the brake levers, or maybe index and middle.
Answer: There is nothing obviously wrong with your handlebar setup. As long the shift and brake levers are easily accessible and you don't have to rotate your wrists or shift your hand laterally along the bar to reach them everything is OK
Maybe I'd consider moving the levers slightly outwards (and I note there is a slight difference in position, the right hand one is slightly more inboard.
Numb hands are a common problem. You don't have to ride with your fingers on the levers all the time. Try moving you hands around the bars and bar ends and flexing your fingers from time to time.
Comment: To add to this, use your bar end grips. Also, make sure your bar and front wheel are aligned; small adjustment problems can translate into big discomfort over long rides.

Thumb ring and index finger


Why should or shouldn't you kill a knocked opponent?

Question: When watching fortnite streamers who like to duo or go in squads, I often see some of the better players not immediately killing the enemies that they have knocked. What's their reason for not finishing them off?
Comment: Иво Недев's answer explains it quite well, but basically it's not worth it because they can't do anything but wait for their team and living opponents are more dangerous and more important to focus on. Besides, knocked down players die on their own and it's not worth it wasting ammo (so I've seen people use their pickaxe to finish off knocked down players so as to not waste ammo)
Comment: I think this question can apply to many other battle royale games that also have a down mechanic.
Answer: There are few reasons and/or strategies either way.
You should concentrate on the alive and shooting enemie(s) instead of killing off the defenceless ones. The knocked out opponents will still be there after your next fight, but if you start finishing them immediately, their friend(s) will come and kill you and you've lost the game.
Eventually you will acquire a gaming sense where you'd know if you can afford to kill a downed enemy based on the location of their friend(s).
You can also add the factor of strategy into this. You can pretend to be finishing off a downed enemy and quickly turn towards the location of their friend(s). They would assume you wouldn't be expecting them, as they can see the red bar of the knocked teammate going down fast.
You can also use a knocked-down opponent as bait. Generally, teams would try to help each other, so if you start finishing off a downed enemy, their friends might try to save them and get out of hiding.
TLDR;
Finish off a knocked opponent if you're safe from counter attack, otherwise always shoot the living first so that you don't lose the game by getting killed yourself.
Comment: Additional reason to finish: if the downed player is able to see what you are doing, but his teammates aren't. Pair of spying eyes.
Answer: A few patches ago, Fortnite added "siphoning" to every game mode. This means that when you kill an opponent, you get 50 health (or shields, if you're at full health) back once the kill registers. In duos and squads, it is not enough to knock the opponent for the "siphoning" effect to trigger. You actually need to kill them for it to count.
Because of this, more often than not, if you have a second or two during the battle to spare, it makes sense to kill the downed person. If you are being rushed, however, and have a lot of health and shield, it makes more sense to fight the living opponents first.
Comment: I don't think this is the case any more:  https://www.slashgear.com/epic-finally-reveals-why-it-pulled-fortnites-siphon-feature-27574910/
Answer: Here are my strategies:
If you are being rushed by an entire squad, focus on the squad attacking you unless you have bad weapons, low materials, or some other disadvantage. In that case, thirst the downed player to get that boost of either more materials, better weapons, etc.
If you think that you have a chance against the people attacking you, box the downed person so you know where they are and damage them a little to get his teammates restless and reckless. In this way, the other team - if you die - still has a timer to get to their knocked teammate. If they aren't fast enough (they do have to go through your box you built), you get the kill.
Also, if you are a solo-squad and getting rushed by three people, I would finish the person to get the kill and make sure the other team can't get a distraction to revive their teammate and make it a 4 vs 1.
tl;dr:
Finish the person if you need something or you are in a bad situation. Shoot the living people if you think you can kill them.


Show github notifications in Mountain Lion Notification Center

Question: Simply put: Is there a way to show the notifications on github in the notification center of the new Mountain Lion?
Answer: The simplest way at the moment would be to install one of the github growl notifiers, either githubnotifier or gitifier, which forwards github notifications to growl and then use hiss (a separate app) to forward growl messages to the Notification Centre.
Comment: Sounds great. As far as I know with the new version of growl we wouldn't even need the Hiss App, as it forwards all notifications to the notification center any way.
Answer: Also you can try GitHub client for MacOS.
Comment: GitHub MacOS client no longer sends notifications as they deemed that feature unfinished and not good enough. They say to resort to email or web notifications.
Comment: Alex, I don't see how this needs any further information. Even hovering over the link shows (1287-github-for-mac-notifications) heaps of information just in the URL. it's a GitHub app that has Mac notifications. Did you click the link?
Comment: How/why does this work? Are you in some way affiliated?


Is it acceptable practice to make the source code of a re-implemented paper available online

Question: It is the usual practice that researchers re-implement others' work for the purpose of comparison or result verification. If for instance researcher A re-implements researcher B's paper and improves it. Is it acceptable to make his re-implementation files of researcher B's paper available as a supplementary file with his published paper?
Comment: You reimplement experiments or methods, not papers. And yes, if you wrote it, you can openly post its source; it's even encouraged by many.
Answer: Science is all about reproducibility. You should reimplement others work and make it available to third parties, just like the original author made his work and results public so that others can learn from it. (They may not have made any software available, but they did describe what exactly they did, after all.)
Comment: "They did describe exactly what they did" One can only hope, anyway. Not all papers are written to the same level of rigor, unfortunately.
Comment: True, and also it is common practice (in CS at least).
Answer: Overall, this is a net positive for the field: people are more likely to try a new method if good code is available. If someone publishes a paper about a method, they expect (and hope) that it will inspire the reader to use it.
Two caveats:

When you make your code available, include a README note stating that this is a clean re-implementation. (if your method makes slightly different choices, and gives different results, be clear that this is not the exact code used by the original authors)
In rare cases, the paper might contain large sections of source code, or refer to protected IP / datasets. In that case, be sure to make your code compatible with the required licensing terms.

Examples: if you copy-paste sample code that is GPL licensed, or if the package depends on sensitive patient data, these things could affect what or how you redistribute. For a pure method paper, this usually isn't a big problem.
As for how to make the code available- hopefully your journal makes it easy to share code! If your journal still thinks that supporting info means "ugly PDF", services like Zenodo allow you to publish github repositories (or other artifacts) as separate citable resources. See: https://guides.github.com/activities/citable-code/
Answer: This is very much acceptable nad I encourage doing so. If you have reproduced someone else's work, it is also very appropriate and helps document your effort and further validate the original author's work if you publish your implementation of it.
In fact, there is actually a scientific journal with the explicit purpose of publishing reproduced work like you describe. The journal is ReScience (and I should mention that I am also associate editor for signal processing there).


Tennessee landlord's rights on charging tenant's "on file" debit card without authorization

Question: Is it legal for a landlord in the state of Tennessee to charge a tenant's debit card electronically (using information stored from a previous transaction) without the tenant's knowledge, presence (neither of card or card holder) or authorization?
Comment: Errm, I think this is narrower enough to be answerable: charging on a debit card without authorization.
Comment: If someone charges your card without your authorization, your first course of action should be to dispute the charge with the card issuer.
Answer: The basic legal limits on card use are here. The law is framed in terms of an "access device", which includes debit cards, PINs, telephones and so on (there are other laws about credit cards). It does not include checks and the bank account information that might be used for a one-time ACH debit. Rule 1005.2(k)(1) defines preauthorized electronic fund transfer

A preauthorized electronic fund transfer under Regulation E is one
  authorized by the consumer in advance of a transfer that will take
  place on a recurring basis, at substantially regular intervals, and
  will require no further action by the consumer to initiate the
  transfer. In a bill-payment system, for example, if the consumer
  authorizes a financial institution to make monthly payments to a payee
  by means of EFTs, and the payments take place without further action
  by the consumer, the payments are preauthorized EFTs. In contrast, if
  the consumer must take action each month to initiate a payment (such
  as by entering instructions on a touch-tone telephone or home
  computer), the payments are not preauthorized EFTs.

So the answer is yes or no, depending. 2(m)(2) says

If a consumer furnishes an access device and grants authority to make
  transfers to a person (such as a family member or co-worker) who
  exceeds the authority given, the consumer is fully liable for the
  transfers unless the consumer has notified the financial institution
  that transfers by that person are no longer authorized.

The literal words here say one thing, and surrounding circumstances suggest something else. A landlord is a obviously a person, but a landlord has a different relation to one than a family member or co-worker does – the parenthetical suggests that this clause refers to trusted individuals. The importance of that is that if a landlord is a "person" in this sense, then you are liable unless you have told the institution that he is no longer authorized.
The same section on unauthorized use indicates ties that concept on forced access (robbery at gunpoint) or cards that are stolen or obtained by fraud, also a class of reversals of direct deposits. None of these concepts covers the described use, assuming that the initial acquisition of the device was not by force or fraud. The fact of using a device without explicit permission in some instance does not constitute fraud (which involves making a material knowingly false statement that the consumer relies on to agree to an arrangement).
The use in question is covered in 3(b)(1), under the rubric "Funds Transferred Covered" (i.e. whether the use is an 'electronic funds transfer', which is regulated):

A transfer from the consumer's account resulting from a debit-card
  transaction at a merchant location, even if no electronic terminal is
  involved at the time of the transaction, if the consumer's asset
  account is subsequently debited for the amount of the transfer.

These regulations are about your relationship to the bank, the question being whether you have a legal basis for making the bank absorb the loss. There is little chance that this law would make you not liable to the bank (i.e. they would be required to return the money taken from your account). There could be some recourse in case your agreement with the bank specifically prohibits recurring charges with a debit card, but it is unlikely that there is any such restriction. Assuming you did not previously put the bank on notice that the landlord is no longer authorized to charge your card, then you have no recourse against the bank.
Any recourse would then be against the landlord, where the specific issue is whether the charge is or is not within the scope of an agreement. If you use a debit card to pay rent and in some month you indeed owe rent, then the landlord has not torted you by charging the next month's rent. If, however, the landlord gets the idea that your bank account is a source of free beer money thus the use is not covered by an existing agreement, then the charge would be wrongful, and you can sue the landlord. I will assume (since you don't specify the purpose of the charge) that the charge is in connection with an amount owed by you.
There is no statute that requires specific "for each use" authorization of debit card charges: any such limitations would arise from explicit agreements between you and the bank, or you and the landlord. If you have such an agreement, say with the landlord, which says that the use of the card is a one-time use, then only a one-time use is authorized. Otherwise, there is no implicit requirement that each and every transfer must be specifically authorized. Informing the institution that the particular person is no longer authorized is your only recourse.
Comment: tl;dr: If (1) you previously authorized a person to use your debit card, and (2) you did not notify the person and/or bank that the person may no longer use your debit card, and (3) you have a valid debt to the person; then the person is justified in using your debit card to satisfy the debt?
Comment: I don't know of any law extending this to "notify the person": the law just regulates banks. Fraud would be the one limit on use by the person that I know of.