How shall we frame our upcoming revisit of the Don't Guess the System Policy?

Question: As a community, we should discuss how to frame the upcoming revisit of the Don't Guess the System Policy. We need a transparent and fair vote, so we ought to establish voting rules that prevent influences that negatively impact the transparency of the voting process. We have to acknowledge our initial situation and the expression of the will of our community therein.
Comment: Does this answer your question? [Revisit III: Don't Guess the System policy](https://rpg.meta.stackexchange.com/questions/11658/revisit-iii-don-t-guess-the-system-policy)
Comment: Revisit has happened here: https://rpg.meta.stackexchange.com/q/11658/23970
Comment: @ThomasMarkov This is an ought/is-difference, but sure we can close this. I have no idea why we should do it, though.
Comment: Instead of closing this as a duplicate of the revisit, we should close it as a dupe of its upcoming post mortem. See https://chat.stackexchange.com/transcript/message/59013095#59013095 and following.
Comment: @Akixkisu [It was Nitsua's idea](https://chat.stackexchange.com/transcript/message/59012676#59012676)
Answer: Once a re-re-revisit is posted, lock it for a week.
This lets people draft up answers and prevents things like Fastest Gun In The West. It means that there will be an exact time at which the question will be unlocked and answers can then be posted at roughly the same time.
People will probably have free time somewhere within a week to draft an answer, so people who have five or six full days of work over each week will still have a chance to create answers, but I have no good reason for it to be only one week and not seventeen weeks other than that at some unknowable, arbitrary point, it would be too many weeks.
People have thought about this a lot so they probably already know much of what they would say and a week to get that all down on paper sounds good to me.
Comment: @Thomas Yeah I'm not really sure how those interact, but an answer could, theoretically, be up for a very long time before another is posted which means votes and comments and revisions will all get front loaded onto that question. I can't know what, if any, effect that might have on the final outcome, but I'll be happier safe than unsure
Comment: @Laurel Because then their answers may not answer however the actual question is phrased. If the actual question is posted, people can model their answers to address precisely what it brings up *and* it lets people comment on the question post for clarifications and alterations which may have impacted those same answers
Comment: So an awkward correction on something which is that there is no good lock type for this, which is to say, no lock type that will prevent answers but not comments and votes, and I'm not sure we'd want to stop those. We can go with just having the question closed for that week, though. I'll trust folks not to reopen it prematurely
Comment: It's been two days and we haven't seen an answer in favor of keeping the policy so the experiment has failed.
Comment: Given the long time period we're proposing, and the use of the featured tag, I'm not sure FGIW applies here. If the voting period were a day, yeah, it would be a problem, but it shouldnt be an issue here.
Comment: Why not just feature this post for a week and tell everyone to think about what they'll post (so there's no need for a lock when the actual discussion is posted)? Just an idea.
Answer: Wait an arbitrary (at least a month) amount of time until a clear winner emerges
Obviously, having voting end after a day or two is nonsense. Some people, who are active community members and have seen DGtS and formed opinions on it as it applies to this site, are not active every single day, or even each week. I suggest at least a month of time (which is how long, at a minimum, it takes for the featured tag to run out anyway), and if, after that, the scores amongst various answers are still very close, we should wait longer. People will, obviously, disagree about whether a score of 25 and a score of 23 means the 25-scoring question should be adopted site wide, but there would clearly be a lot of people disagreeing with that kind of change. Therefore, I suggest we wait until a clear difference exists.
I am not putting forward a precise definition in score or percentage for what counts as a clear difference between answers simply because I do not have one. This is the Sorites Paradox; just as I do not precisely when a heap of sand becomes a pile of sand, I do not know when close scores reveal a clear winner. It is not an exact thing, and that's okay.

Yes, this all has problems, and yes, there are ways to game and cheat the system, but I do not care about these. Why? Because I trust the people here not to do those things.
Comment: FWIW the featured tag is automatically removed after a month (usually slightly longer for reasons) and we'd usually wait at least that before considering a discussion fully settled.
Comment: Yeah, so this is basically what I expected when I said "leave it up to the mods".
Comment: IIRC when I was a mod and we did a re(-re?)visit some behind-the-scenes conversation was that we'd want to see a pretty clear signal to *change* stance: we hypothesized that something like 3-to-1 in favor of position A would probably be enough to warrant a change. Close calls or even a 60-40 split in favor of a change didn't feel like enough. And there's a lotta grey left in between. IMO, positive votes give an unambiguous signal, while negative votes are less useful, effectively double-counting positive votes elsewhere. (Presumably.) Doppelgreener or SSD or mxy might recall better than me...
Comment: ...and current mods could always dig back into those discussions if they care to do some spelunking =)
Comment: @Someone_Evil Yeah, this answer, to me, feels a good bit like a "because *of course* we would do this" kinda thing, but I still wanted to get it out there anyway. I will incorporate the featured tag mechanics into the answer though
Answer:
How shall we frame our upcoming revisit...?

With an eye toward the actual stakes.
Frankly, which way we end up going with DGtS isn't a huge matter for site health. Montagues argue that one way of handling it causes net good for the site while Capulets argue that's a net harm. If we change the practice those will swap. (I'm a Montague, by the way. Forrealz: it's a family name on my father's side.)
All of the above are reasonable people who care about the quality of the site and its utility for visitors. I say this informed both by faith and experience. They're drawing conclusions from their experiences and from mainsite events that admit nuanced (even conflicting!) interpretations.
Pulling back the curtain a bit: I was an elected moderator for three years and can't think of a practice that generated as much discussion (in meta and in chat), and which generated as little actual problems on mainsite. Some passionate arguments on meta, sure, but comment-sniping? Edit warring? Rage-quits and deletions and abusive language? Nope.
The actual stakes, then are the users involved.
It'd be really easy to come in heavy-handed and run a revisit in a way that ends up alienating some pretty-reputable Montagues or Capulets or creating a meta-mess that sours new users who come across it years from now.
A good process will:

thoroughly and succinctly (good luck!) summarize the evolution of the issue, with plenty of meta links, so that users new(er) to the topic can get up to speed easily;
allow enough time for thoughtful answers to come in, thoughtful engagement with those answers, and thoughtful response-answers to come in;
lay out clear indicators of when action-/decision-points will be triggered--not so that people can game the system, but so that people are not surprised or undercut or cut short.

If you ask me--and nobody did--I think the current churn on meta is enough of a "heads up" that a revisit will come. No need to pre-announce it or anything.
Take some time to compose a good post laying out what's asked here and summarizing the state of affairs.
Make it clear in that post that you'll be waiting at least a month, or a few weeks after the latest answer's come in (whichever's longer) before evaluating what the scores might indicate.
Make clear in the post that a signal of 3:1 in favor of change is considered strong, that a signal 3:2 in favor of change is not considered strong enough to change the practice, and that anything in the middle is going to cause mods distress so please don't let's land there. (Or whatever you think are good thresholds.)
Comment frequently (every three or four days?) on the main post summarizing where things stand ("two new, good answers have come in this week--make sure to take a look and vote/comment, people" "no new posts this week but a bunch of voting, two Montague answers lead by small margins" "it's been two weeks since an answer's come in; if you are intending to write one but just haven't had the time please comment so" &c.).
When it's been a few weeks since it's been active, feature the post and start the "clock" anew. Now, with some well fleshed-out answers and discussions, is a good time to get some new eyes, some new questions, into the mix. (Add a little preamble to the post, maybe, explaining that this has been done?)
And then, when that clock's run its course... pray to whoever you think is listening that it's a clear (enough) signal one way or the other.
Comment: 3:2 not being enough to change the practice seems to give the policy far too much intertia. I know that if the scores settled at +60 repeal and +40 remain, I'd be a little salty if I were in favor of repeal.
Comment: Oh, and I do think it should be the moderators/a moderator posting it. This is a prime case for moderator action: there's a thing to be done, there's no particular reason it has to live under one user's name rather than another, and we've already gone through a process to identify a few "chosen" users to handle unusual things.
Comment: That may well be. I'll lay my cards on the table: I *am* in favor of change, a position I tried not to let get too much air while I was an elected mod. That said, I'm also small-c-conservative enough, or perhaps it's "gun-shy about upsetting the boat" enough, to want to somehow give some weight to the ten years of experienced and careful and thoughtful users who felt differently than I do. But this (where to put the cutoff) is definitely one of those things where there isn't a "right" answer, and even if there were there'd be no way--even in retrospect--to know...
Comment: "(I'm a Montague, by the way. Forrealz: it's a family name on my father's side.)" - ...That's awesome. :D
Comment: ...whether we got the "right" answer. All of which, in my experience, indicates that treating the people right--since there *will* be saltiness--is of paramount importance.
Answer: Note: This represents my idea as a user, not a mod. Don't take this as any kind of official stance or suggestion that this is something the mod team are planning to do.

Don't make it a re-visit
Clearly this will be a re-visit, this is ground we have discussed before and it is impossible to pretend that hasn't happened. However I would like to propose we create a new meta as if we were discussing a solution to problem for the first time.
The Problem With a Re-visit
By treating this discussion as a re-visit it becomes somewhat of a false-dichotomy, to repeal the policy or continue with no (or minimal) changes. While in reality we have a near infinite array of options and can choose to implement any solution we choose.
I believe this repeal/don't change option was reflected in the original results of the most recent revisit. Prior to become a mod, I voted against the moderator proposal to repeal at the time as it advocated for a complete reversal of the policy.
While I believe there is some ground to relax or modify the currently strict version, I am not in favour of a complete removal. If we make the next meta on the topic a re-re-revisit I fear that the same problem will force me to choose to keep the policy.
How this might work
The moderator team can workshop a question that describes the problem, identifies what has been tried and the pain points with the existing options. Comments on this and the other metas will help to identify what should be included here, as well as the opinions of users. Clearly this is impossible to get 100% perfect, however I believe the moderators are in the best position to make this post.
In line with Medix2's answer to this meta we can then lock this post after posting for 1 week. Giving time for feedback to be incorporated into the main question and for users to draft their answers before voting begins.
Answers to that post would take the form of 'policy' suggestions. A complete solution to the actual problem (questions that require system tags not having them), in a similar format to the "Don't guess the system", policy clarification meta.
I believe a question in this format will allow us resolve this in a single meta rather than requiring one for discussion and another for implementation. Answers will have clear actions for users to understand. The standing policy going forward would have a single source rather than a series of posts as we have had in the past.
How would voting work?
As Medix2 suggests we need to wait at least a month for voting to stabilise and for all users to have a chance to have their say. As for thresholds for acceptance, I hope it will prove to be a non-issue. That one answer or pair of similar answer will emerge as the clear favourites amongst the community, similar to how the results of the 5e meta panned out. If it is close, I hope we are mature enough to discuss and find an appropriate solution, perhaps a compromise between the top few answers (providing they aren't directly opposed).
I think it would be detrimental to agree to fixed thresholds ahead of time as it might lead to "We agreed to rules that say the result is X, but common sense says the result is actually more like Y" (unlikely but possible). Lets allow common sense and good judgement to prevail rather than overly prescriptive rules and formal voting.
Additionally I'd hate for any formal voting rules we made to become precedent for all meta discussions in the future. By not having rules there is no risk of that.
Comment: I'm in favor of a meta that encourages us to figure out third options for handling the situation that are neither "no policy" nor "the policy as-is", and would much prefer that to a meta that winds up with us focusing on that dichotomy alone. However, we also need to be open to the idea that "no policy" or something like it will likely show up as a serious suggestion to that meta and may even turn out as the most popular choice. (I mean, I expect a third option to win, but even I can't say how this will turn out.)
Comment: It seems to me these guidelines that may work as a middle ground are probably going to be integrated as part of a repeal proposal anyway. No one ever has understood "repeal the policy" to mean "add whatever tag you think might be it, no matter how ambiguous the question", and we need to stop characterizing it that way.
Comment: For me, I don't think it's realistic to expect an in-between solution to work, and I doubt I'd vote for one—I would probably prefer no policy over that. The primary advantage of the strict policy is eliminating arguments. Any weaker, nebulous policy I can imagine is just going to have people arguing about whether something fits or doesn't. At that point we might as well cut out the middle man and just have arguments about the merits of adding a system tag or not based on the practical question, not on how it fits some inevitably-under-defined policy.
Comment: Can you give an example or two of what sort of policy implementations you think there are between a total repeal and the policy's present implementation? I'm finding myself unable to come up with any in between, which makes me think this idea won't work, or at least, will just be "repeal" vs. "policy as is".
Comment: @doppelgreener I hope that 'complete repeal' is one of the answers presented, I likely won't vote for it, but will abide by it should it emerge as the winner. It should exist as it represents the community. I also hope that there are a few solutions we haven't heard or new ideas that this method would encourage where previous revisit have failed.
Comment: @Thomas Markov I can think of some 'guidelines' that may work as a middle ground to the current policy and no policy. But it's outside the scope of this meta to present them here. I only include them for the fact that when posing the question we should allow for their theoretical existence.
Comment: @linksassin Were you expecting proposals for repeal to come without guidelines for handling questions in absence of a policy?
Comment: @ThomasMarkov My issue is that some users will take it that way. I'm expecting proposals to repeal would include something like *"Only add it if you are sure."* and users with good intentions but limited experience will add it believing they are sure. I'm hoping for stronger guidelines that can indicate the kind of evidence required to be 'sure'.
Comment: @KRyan perhaps you are right, and voting will indicate that. However I don't want the meta question itself to preempt the ability for such a compromise to exist.
Answer: Just let the moderators handle it.
Someone_Evil has already asked us about what the mods are unsure about (votes changing ex post facto). We don't need the formality you proposed in your answer. We elected them because we trust them to give guidance to the community when necessary, so let's let them work.
Comment: I'm not sure what I'm supposed to take away from a five year old post about a different set of moderators.
Comment: @Akixkisu I don't think it's a matter of faith. I don't doubt that your proposal is genuine and well intentioned. I just disagree with its utility and necessity, which doesn't have anything to do with you personally.
Comment: @Akixkisu [this is very incorrect](https://rpg.meta.stackexchange.com/questions/11602/how-shall-we-frame-our-upcoming-revisit-of-the-dont-guess-the-system-policy?cb=1#comment39532_11604) and my attempt to establish a useful Q&A to address the tension between the mods at the time and some of the community was an unmitigated disaster.  It was very much bound in time and place.
Comment: "Set the terms of policy discussions, and begin and end them" is not carved out as a thing diamond mods are solely responsible for, such that we should just go "hands off, leave it to them" just because they're mods. This is a community activity, and moderators do this as an extension of community membership. Moderators are best placed to do this in exceptional situations, but this doesn't mean we should just take our hands off as a community and divest ourselves of involvement. If moderators happen to open the meta, they would even be helped by understanding how we want to go about this.
Comment: The reason Akix may be pointing to that meta is because it came from an era where we found that moderators were acting as the sole arbiters of community policy to the exclusion of the rest of the community, and it was very much not working. Moderators have started several recent major policy discussions because of the issues we were seeing, and mods certainly have an easier time doing this than anyone else on controversial topics, but that doesn't mean community members cannot do this or at the very least get involved in setting the terms of the discussion.
Comment: So while I might upvote an answer that suggests there's some good reason the mods should be handling this all on their own, I cannot support an answer that appears to come from the POV that this is solely their domain from the outset and not our business.
Comment: Right, but _why_ are we trusting them to handle it to the point we wouldn't even discuss it ourselves? This is putting the totality of the responsibility of organising that meta on the mods and suggests we shouldn't even be involved, on very little basis I can see other than "because they're the diamond mods." That's the, y'know, "diamonds should be handling this because it's their job" kind of position. I do trust them, but that doesn't make it solely their responsibility and not our responsibility too.
Comment: @Akixkisu A most excellent choice.
Comment: Right, I read it, and it might as well have been written about another planet. Our moderators are great at doing what is suggested there, and what I suggest in this answer is exactly the kind of exception handling they should be doing.
Comment: No, this is a community vote, not a "The mods have spoken, therefore the issue is settled." matter. And moderators should act as community members in that regard. They way they have handled that last time caused severe issues, and we do not want to repeat them, after all we have a majority vote that is quite clear.
Comment: I voted for those same moderators. I trust them to handle exceptions and honour their words - but I do not accept them as dictating the frame of the discussion or as community leaders whose views I need to serve. Moderators are not our policy decision-makers - we are as a community, and they are an equal part of that as members, not our leaders.
Comment: @doppelgreener I'm not saying "this is not our business", I'm saying "I trust them already to handle it".
Comment: @KorvinStarmast I think I can do one of two reasonable things here, 1. discuss this with you at length, explain to you my reasoning, listen to what you have to say on the matter or 2. drop it and acknowledge that we could argue here. I employ the second option
Comment: Please read ["Is something wrong?" Yes: Too much moderation](https://rpg.meta.stackexchange.com/questions/6129/is-something-wrong-yes-too-much-moderation) this is a stark issue.
Comment: As far as I'm concerned I will simply quit the community if we are going into a vote that then gets cutoff at an arbitrary point again, if we have a vote that is not tranparent in that manner or that disregards our long voting process.
Comment: The content. As it is true for moderation in general, regardless of who that moderator is.
Comment: I don't doubt that they have the best interest of the site in mind, and frankly you of all people sbould be receptive to also have good faith in me.
Answer: How we could do that:
We should acknowledge that during the last year, we accumulated an overwhelming majority in favour of "Revert the policy, and treat these edits like any other." So we should treat it as our status quo in the regard of voting onus. Any Answer that advocates keeping the "Don't Guess the System" policy should gain a demonstrable majority by a large margin after a voting period of three months. If the voting process is close at all, we should treat the long process that led to the overwhelming majority in favour of "Revert the policy, and treat these edits like any other." as our policy, and we can only ask our moderators to enforce it as the will of our voting as a community.
If the majority should change again during an enduring voting process, we shall revisit the policy as soon as possible, but at least one year after the last revisit.
Initiating a revisit shall be a community process that stems from within a community of equals of equal power. So those of us who carry the elected moderator role shall not initiate a revisit. As moderators are otherwise also regular community members, they shall participate as any regular community member would in all other matters.
Our revisit shall start on the first of July 2021. This two-week span should give all of us ample time to draft answers that may gain momentum at the same pace.
We shall assume that all discussion related stems from good faith.
Comment: -1 If the results of the vote will be predetermined to be "Revert the policy" with no regard to actual votes (unless they reach some unspecified "large margin"), then it is the opposite of "transparent and fair vote". Why even make it a vote then? Just declare a policy as de-facto in effect and be done with it.
Comment: @Akixkisu I personally haven't voted on the original question because I haven't had a reason to look at a year-old discussion that has reached a conclusion of a policy that I don't object to. If I had, I would have voted against the top answer. I get that it seems you have been arbitrarily disenfranchised by mods because of the rules of the previous vote, but that doesn't give you rights do disenfranchise people like me. If you want a fair vote then come up with a way that **is fair** on it's own and not just designed to compensate for past wrongdoings.
Comment: In case it wasn't clear - my main objection was that there was a default result that was presumed to be a winner (even while having less votes than others). Additionally (but this is relatively minor point) I also object to the ban on revisiting policy in less than a year, which seems to be designed to silence all the opposition.
Comment: @Akixkisu No, if I had, I would have posted an answer. I currently have neither up nor downvoted the "Just let the moderators handle it". Because while it _risks_ ignoring the wishes of the community, this answer _explicitly advocates_ ignoring part of the community that might be in favor of keeping the system.
Comment: "This two-week span" That's the two-week span from now til 1st July, right?
Comment: @doppelgreener yes, but we could adjust that or I could phrase it more clearly :)
Comment: @SilentAxe do you have a better proposition in mind?
Comment: @SilentAxe The vote over there sits at a score difference of more than 20 votes in favour of reverting the policy, which is a clear majority, but that is not how we enforce things due to the framework of the last vote. If there is reason to define a large margin, I'm very much open to transparent definitions. So "Just let the moderators handle it." is that reality in which we have an answer that has a score that is more than 20 higher which we currently disenfranchise, see https://rpg.meta.stackexchange.com/a/11597/44723
Comment: @SilentAxe When it comes to the established status quo of our community voting process, we have to take in the result of our current voting. So any new vote does not happen in a vacuum. We would vote to confirm or deny those results. So the question is, should we merely not re-vote and affirm the votes that we already did as the new policy (to revert old policy) and be done with that, or should we revisit and if we do visit, what position has the onus to overrule the other? I think an alternative would be to say "the majority has spoken." as you suggest.


Is 45 min enough time to catch my next flight in Copenhagen?

Question: I am flying from the US to Warsaw. I go thru Copenhagen and they only allow 45 min from one flight to the next can I make it. I will have 1 checked bag and a backpack.
Comment: 45 minutes happens to be the official [minimum connection time](https://www.cph.dk/en/practical/transfer/connection-time) for intercontinental connections at Copenhagen. The main risk will be the wait for border control, which depends on whether you're an EU citizen and can use the automated lanes. Actual walking distance will be about 20 minutes at worst.
Answer: As Copenhagen and Warsaw are both in the Schengen area, you will immigration in Copenhagen. Although you won't need to get you checked bags, immigration could still take a while, depending on when you arrive.
If you booked both on the same ticket, your carrier has a responsibility to get you to Warsaw, so even if you miss your second flight (e.g. if your first flight is delayed), you should be on the next flight.
If you booked the tickets separately, then it's your responsibility to get to Copenhagen on time for your flight to Warsaw, and a late flight from the US is not a valid excuse. You would be responsible for any fees from changing the time of the flight.
Comment: Plus, if you have booked different tickets you will have to pick up your luggage and check it in again for Warsaw and go thru security again. 45min is definitely not enough time for a layover with two bookings.
Comment: Not necessarily: most airlines do interline. The risk with separate bookings is that the passenger is not protected if the first flight is delayed (although I've seen exceptions to this).
Answer: It all depends on your airline. I was in a similar situation this year, flying back from London to Tokyo via Hong Kong. There should have been a 2 hour transfer time but due to a late start and bad weather, we arrived with only 45 minutes until the next flight.
I was flying Cathay Pacific and they really impressed me, as soon as we got off the flight there were attendants waiting with signs for the different connecting flights. I joined the group for Narita, Tokyo and we were taken through a special immigration check route which bypassed the queues. I can only imagine this is normally reserved for first class passengers.
All told I was in Hong Kong airport for just 15 minutes before I boarded my next flight. Without a doubt, the shortest transfer time I think is possible in an airport that size.
If you're flying with two different airlines I don't think you'll make it in 45 minutes.


Hindi tweets datasets freely available

Question: I am working on macaronic language analysis. I need a dataset of hindi tweets or other devnagri languages. Could someone send me the datasets or the links where I can find them?
Comment: Can you use Twitter's search function and/or write a small program that grabs tweets in the appropriate language in real time?
Answer: The Streaming APIs give developers low latency access to Twitter's global stream of Tweet data. A proper implementation of a streaming client will be pushed messages indicating Tweets and other events have occurred, without any of the overhead associated with polling a REST endpoint.
If your intention is to conduct singular searches, read user profile information, or post Tweets, consider using the REST APIs instead.
Please refer this link: https://dev.twitter.com/streaming/overview

Hindi tweets datasets freely available


Is there another way to represent this summation?

Question: I wish to calculate $\sum_{x=1}^{n}\sum_{y=1}^{n} f(x,y)$ where $x>2y$. I can do this by changing $y$'s upperbound to the floor of $(x-1)/2$ but this makes simplification of the summation harder later. Is there a way using inclusion-exclusion to simplify this sum?
Comment: What is $f(x,y)$ ? A polynomial ?
Answer: No need to evaluate a floor.  Since $x > 2y$, $x \geq 2y + 1:$
$$\sum_{y=1}^n \sum_{x=2y+1}^n f(x,y).$$
Answer: According to my own experience, for the purpose of simplifying a double sum, the first and most tricky and powerful step is to suitably extend the defining domain of $f(x,y)$ so that we have
$$\sum_{x=1}^n\sum_{y=1}^nf(x,y)
=\sum_{x=-\infty}^{+\infty}\sum_{y=-\infty}^{+\infty}f(x,y),$$
which is usually written in the notation
$$\sum_{x}\sum_{y}f(x,y),$$
for the sake of emphasizing that we now have a summation of "standard" form in hand.
In other words, we simply define $f(x,y)=0$ when $x<1$ or $x>n$ or $y<1$ or $y>n$. For this problem, we can define $f(x,y)=0$ for $x\le 2y$. The remaining work is routine, just to simply
$\sum_{x}\sum_{y}f(x,y)$
by using standard transformations and known formulas. For example, instead of writing
$$\sum_{k=0}^n{n\choose k}=2^n,$$
I prefer the "standard" form
$$\sum_{k}{n\choose k}=2^n.$$
This trick sometimes brings great convenience, and maybe helpful to your specific problem.


Is "The Cabin In The Woods" really meant to be a metaphor for the horror genre?

Question: Everyone seems to be supporting the idea that The Cabin In The Woods is a metaphor for the horror genre in film, but I have yet to see anyone who was part of the production admit to it. I will admit it makes sense, but are we so certain that it wasn't meant to be about Lovecraftian horrors ending the world? Is there any secured information from the filmmakers themselves about the intent of the film?
Comment: Basically the film is sending up (parodying) the consistent tropes espoused by Robin Wood in his essay "An introduction to the American horror film"
Comment: But, is it? I'm asking if there's any proof that a parody was the intent of the production.
Comment: I don't think metaphor is the word you are looking for. More like parody or reflective.
Comment: "Everyone seems to be supporting the idea that The Cabin In The Woods is a metaphor for the horror genre in film" -- says who? Such proclamations should be proven via links to plenty of sources, which should be easy if "everyone" supports this idea.
Answer: The very short answer is yes and no. The film was clearly intended as a comedy-based deconstruction of the horror genre, but the makers were also quite careful not to fall into the trap of simply making a straight parody (a la 'Scary Movie' or 'Tucker & Dale Vs. Evil').

Filmmaker: So far we've been talking about Cabin as strictly a horror
  movie, but it's also got some very strong comedic elements. Was it
  difficult to balance those two genres?
Goddard: It was the hardest part of the job – maintaining that tone.
  Because we do both, we go from horror to comedy and comedy to horror.
  And you have to be really careful with that, because with comedy it
  would have been very easy to veer too far into parody. And if you go
  the other way, suddenly you're becoming that which you're commenting
  on. And so we really had to walk the line.
In terms of balancing the tone, I found what it usually came down to
  was my gut reaction. There's no way to completely intellectualize it.
  I just had to think about each scene and say, "Okay, we've gone too
  far here, let's dial it back," or, 'this is a good place where we
  could take things a little further." You just have to trust your gut
  as you go. - A Conversation with Cabin in the Woods Director Drew Goddard
Answer: I think it's pretty clear that it's a horror movie about horror movies.  For example, in the interview quoted by @user7812, Goddard says, "I wanted it to be a movie about the genre..."
Also, in an Onion AV Club interview with Whedon, Whedon describes the Sitterson and Hadley characters as screenwriters like Whedon and Goddard: those characters are crafting their own horror movie inside the movie.


Is it safe to erase ~Library/Developer?

Question: In the user Library, there is a Developer folder with about 3.2 GB of space (2.8GB from DocSets and the rest mainly from Xcode/iOS DeviceSupport). I had Xcode installed, I presume these are from that? I no longer use Xcode, is there any downside to erasing these folders? If I install Xcode again wouldn't it restore what is needed?
Answer: No its not safe to delete everything in:

~/Library/Developer

Doing so could cause you to lose backup snapshots, any generated Archives for applications and other customizations set in the XCode IDE.
Specifically within the Developer folder there should be two additional folders.
"Shared" and "Xcode"
Shared contains documentation that you have downloaded using Xcode, depending on how you work and whether you have internet all the time you might not want to trash that, but worst case you can just re download it, so if you need space, and are not concerned about offline documentation, here is where you can grab back some space.
The Xcode folder contain a lot, and potentially some things you might not want to lose.

Archives

If you use Xcodes Archives organizer feature, deleting this will wipe out any Archives you may have.

DeveloperPortal 5.0.db

Contains information probably about using iTunes Connect in Xcode, I would guess its disposable, but you may have to reconfigure Xcode to talk to Apple for App Store distribution, etc.

UserData

This generally contains any changes you made to Xcode color schemes and font themes as well as any changes you may make regarding Key Bindings in Xcode, again this stuff should be pretty small and is probably something you don't want to throw away if you spent any amount of time tweaking those kinds of Xcode settings, you probably just don't want to trash those changes made.

iOS DeviceSupport

Probably some information relating to iOS devices that you have attached to and tried to use in Xcode, should be safe to delete.

DerivedData

Stuff in the DerivedData folder is generally pretty safe to delete, it is all the stuff that gets generated every time you press the build button in a project. It includes the generated log and applications executables and libraries for all the products you build in a project.

Snapshots

If you use Xcodes built in snapshot tools as a means of version control, wiping out your snapshots will wipeout the possibility of reverting to older snapshots.

iOS Device Logs

Safe to delete, unless you need your logs, you would know if you need to keep them.

Templates

Your custom project templates, like a UserData you probably just don't want to trash those changes made.
Answer: If the only two directories you have in ~Library/Developer are Xcode and Docsets (or Shared/Docsets) then you should be safe to delete that folder. If you did re-install XCode you would get them (or updated versions) back.
Comment: It's Shared/Documentation/DocSets.
Comment: That's fine then.
Comment: Is it safe to just delete docset? I don't use XCode but need it installed for another program (Adobe AIR) and the tools it has installed.
Answer: If you have installed 4.3 or later version of XCode, it should be safe to delete.
It's written here :
https://developer.apple.com/library/ios/documentation/DeveloperTools/Conceptual/WhatsNewXcode/Articles/xcode_4_3.html
Comment: Answers on Ask Different need to be more than just a link. It's okay to include a link, but please summarize or excerpt it in the answer. The idea is to make the answer stand alone.
Comment: A word of warning. The question relates to ~/Library/Developer, whereas this answer looks to answer /Developer which is a *different* path.
Comment: This page is also no longer available.

Is it safe to erase ~Library/Developer?


Job advertising?

Question: Is there an appropriate spot on here to advertise a latex-related job/commission? Alternatively, would it be appropriate to privately message some users and invite them to apply for a job/commission? Or would this be generally frowned upon as being not what this site is intended for?
Comment: There are no private messages in the network. Either you post a comment or enter TeX.SX chatroom, but all is public, apart from own chatrooms which have restricted user access, but in this case, the effect of your advertisement would be very limited. How about a newsletter, being distributed via TUG, DANTE etc.?
Comment: By the way: Posting a private job offer etc. is not really fair to users. Anybody should be informed and have the chance to apply/getting involved ;-)
Comment: Oops, didn't realise there was no private messaging system on here. Discard that part of the question. I only suggested it as an alternative if a more public offer wasn't allowed. It is far from ideal.
Comment: If you want to ask particular people and they are package authors, you can probably find contact details in their packages. Since these often go stale, your best bet would be to look on CTAN and check their newest/most recently updated packages for these details.
Comment: @Ulysses: Did you found someone to help you with your thesis? If not you may like to take a look at [my website](http://tobiw.de/en) and contact me ;-)
Answer: I just signed up for freelancer.ca (see edit below for more details) and basically you can look for freelancers in specific areas to do your "projects", including LaTeX. From what I can see, some of the freelancers seem to have really solid reviews and even have examples of their work. You can also post your "project" and have freelancers bid on it (but stick with the LaTeX tag only; otherwise, you'll end up with a LOT of bids from freelancers who know nothing about it).
As an alternative to this, it really would be nice to have somewhere on here as a "LaTeX-for-hire" job listing forum. The TUG jobboard seems to be pretty dead (no new jobs since July 2014), and their consultant listing seems to be mainly geared towards heavy/intense/professional jobs.
As far as I can see, the freelancer website seems to be the best place for getting smaller jobs done (although they can do big ones as well, but I would rather have bigger jobs done by a professional with their own website or an owner of a prominent LaTeX package, etc). There really should be an SE alternative to this for smaller jobs (not for huge ones) IMO, or at least a LaTeX-specific one.

Edit: I just finished a project I assigned to someone I hired on there, and he did a pretty good job! There was a lot of back-and-forth communication to make sure the TikZ pictures (in my case) came out the way I wanted them to, but the person I hired at least (can't speak for others) worked pretty hard to make sure I was satisfied. There are some PhD students on there, but I just hired a physics grad student.
Also, you don't pay for the entire project at once, you actually just give a small deposit fee first, and don't pay them more until they give you deliverables/updates half way (you can customise this to set more milestones than just halfway too). This is a good thing since you don't have to worry as much about money going to waste. Of course, as Johannes said, with freelancers you never know what you'll get, but I think this system helps minimise the risks of that (with the payment structure I mentioned).
Note that this is just my experience, but I think if you choose a freelancer wisely you can end up with similar results. I should also say I don't work for the website or anything like that, I was just desperate to get some drawings done for a (overdue) paper and that's why I used them.
Comment: Freelancers are like boxes of chocolate, you never know what you're going to get.
Comment: That is a really good system i think.
Comment: @Johannes_B agreed for the most part, but I think an exception can be made for those with many positive reviews (not from spam-bots of course). I'd say the same rules apply for any online transaction -- buyer beware! ;)
Comment: Just updated my answer with my own experience on the website, if the admins feel its too lengthy or has irrelevant content please feel free to edit it.
Answer: While it would be appreciated here, the proper place on stackoverflow would probably be careers.sx, although that's too expensive for only one job.
TUG has a jobboard, though.
Comment: Yeah, my task is much too small for something like careers.sx. I just want someone to give my thesis a final polish with respect to formatting. And the TUG job board doesn't appear to be active.

Job advertising?


Rear oxygen sensor signal rate of change and p0420

Question: What is the minimum time rate of change (absolute value) of the rear o2 sensor signal voltage that will trigger a p0420 dtc?  This is probably vehicle specific, but a ball park figure would help.  Thanks
Comment: Toyota doesn't give specifics on this. If the rear o2 is swinging up and down at steady speed with normal afr sensor operation the cat is bad. Normal ho2s operation at steady speed should be around 650mV. I'm not even sure crosscounts are used as part pf the monitor strategy. I believe it's, command the afr sensor when the monitor is enabled. Check for specific changes in voltage.
Answer: There are as many different strategies for deteriming catalyst failure as there are vehicle manufacturers. All the formulas are propritary, even a deep dive into SAE technical papers on the subject will reveal little about the details of the varius strategies. It is easier to say what the post catalyst sensor waveform of a working catalyst looks like than what a failed one looks like. A working catalyst waveform will not vary at all in response to ossiclations of the pre-cat sensor when tested at steady rpm. That is not to say that the rear sensor does not change over time. The systems often switch from rich to lean and back over time. This is strategy for fuel mileage improvement and catalyst health.
The rear sensor should show as a straight line with no bumps or ripples. Any ripple no matter how small a voltage change that is in sync with the pre-cat sensor will be viewed as likely catalyst failure.
Reference this scanner graph from a failed catalyst on a Honda

Notice that the after cat sensor (green line) is low on the graph indicating an overall lean mixture and that the voltage amplitude is relativly small. It is in perfect sync with the pre-cat sensor (red line).
Now consider this capture taken after the catalyst was replaced with a new one.

The overall mixture is still lean but now the rear sensor shows no cycling behavior.
Comment: Thanks for the information.  I was working on a filter, and I was trying to find a suitable bandwith so as to avoid both P0420 and P0136.  It's working well now.


Has copy protection ever been used in physical books?

Question: "Digital rights management", DRM, is almost a standard in the e-book industry. Have copyright holders ever tried to protect physical books from scanning, for example in a way how banknotes are protected against counterfeiting?
Comment: Upvoting this because I think it's *interesting*, but I'm not sure whether it'll be considered *on-topic* for the site.
Comment: Basically, they're not books of literature, but I have a couple of "code books" which are very hard to copy (and read) which allow game developers to copy protect their games back in the days before the Internet. Alas, I cannot give more than that due to my rep with this site.
Answer: Look at it this way - the reason why companies need DRM is because digital files can always be copied verbatim, i.e. bit for bit. Companies cannot prevent files from being copied and re-distributed so they need DRM - a system that alters the files in a way that the contents can only be accessed under specific circumstances, e.g. by entering a license key, inserting an official CD, etc.
With hard copies, copying "files" is significantly harder, because one has to get a hold of the physical copy of the product. What was equal to hitting the 'download' button, now requires taking a stroll to the library, or paying money for an actual copy.
Oh, and some more diligent copy centres will not allow you to copy more than a certain per cent of the book. While this doesn't apply to every country, it may still be an obstacle.
Coming back to your actual question, what you are describing is called, per Wikipedia, the "analog hole". While it may be nigh-impossible to decipher a DRM-protected book, or crack a DRM-protected game, once you have a physical copy of an object there is a number of ways you can copy it. Off top of my head, I can already think of a "lamp + tripod + DSLR camera stand", which is not very hard to construct, but is good for practical purposes. Combine this with optical character recognition, and you have a fault-proof home-made analog piracy system. Why fault-proof? Because digital cameras use the same working principle as the human eye, so DRM, in this case, will be more of a double-edged stick than it is with digital content.
There are multiple technologies available, that make traditional scanning and copying impossible. For instance, there is a technology that will make "VOID" texts appear on scanned copy:

All of our paper products are protected by AuthentiGuard Pantograph 4000TM. This patented technology involves the printing of hidden text messages ("VOID", "COPY", "UNAUTHORIZED COPY", etc.) into the background of a document. Text information or other artwork is placed onto this paper. Then, when this "original" is copied of scanned, the hidden word pattern becomes visible on the duplicate. The end result - a clearly distinguishable copy that can not pass off as the original.

Same company sells special paper for books as well, though I was unable to find examples of it being used,
On a more light-hearted note, there is a book that is printed with a special kind of ink: it is sold in an air-tight package, as the ink starts to fade upon contact with air. It is called El Libro Que No Puede Esperar - The Book That Can't Wait, This provides a good incentive to actually read the book, before it becomes blank paper.
Comment: That was really interesting. But it depends on UV fluorescence which assumes higher than ambient UV in the copying machine. Modern copiers tend to use white LEDs rather than a fluorescent lamp (a low pressure mercury vapour lamp lined with a fluorescent powder which emits a lot of UV) so I suspect this countermeasure is already failing.
Comment: "Digital files cannot be made uncopyable, any more than water can be made not wet." - [Bruce Scheier](https://www.schneier.com/crypto-gram/archives/2001/0515.html#3). Protecting a novel is impossible, as the last report the book can be copied by hand.
Comment: "Protecting a novel is impossible, as the last report the book can be copied by hand."   I present to you the Bruno copy protection algorithm. Bruno breaks hands.
Comment: This technology, or something very similar, was used experimentally in the early 1990s in the UK for paper driving licences. They would appear normal, but a photocopy would result in a word being displayed in the background of the copy (can't remember if the word was 'copy' or something else). Having tried it they forgot about it, then a 10~15 years later gave someone a hard time when he sent a photocopy of his licence in and they tried to claim the revealed word showed it was a fake!
Comment: @JFA - the website of the manufacturer is quite specific and detailed. It's UV. You could probably use the approach with IR but again white LEDS emit almost exclusively in the visible spectrum.
Comment: It strikes me also that this whole business does not _prevent_ copying, it _detects_ copying. As an aid to prosecution it is comparable to a watermark or a trap street on a map https://en.wikipedia.org/wiki/Trap_street. Both are protection mechanisms which is what the OP specified.
Answer: This isn't against scanning specifically, but creators of ancient and medieval texts did attempt to protect their work against theft, vandalism and misattribution by writing curses on the book. You might consider this a form of early DRM.
For example, from the Wikipedia article on Book curses:

[...] Ashurbanipal, King of Assyria from 668 to 627 BCE, had the following
  curse written on many or all of the tablets collected at the library
  at Ninevah [...]:

I have transcribed upon tablets the noble products of the work of the scribe which none of the kings who have gone before me had
    learned, together with the wisdom of Nabu insofar as it existeth [in
    writing]. I have arranged them in classes, I have revised them and I
    have placed them in my palace, that I, even I, the ruler who knoweth
    the light of Ashur, the king of the gods, may read them. Whosoever
    shall carry off this tablet, or shall inscribe his name on it, side by
    side with mine own, may Ashur and Belit overthrow him in wrath and
    anger, and may they destroy his name and posterity in the land.
Comment: @Agent_L It sure does - "divine rights management"
Comment: The curse doesn't protect against reading or duplication so it can't be considered DRM. DRM doesn't protect against deletion or destruction, it actually performs those things if it finds you wanting.
Comment: And of course it will have been no joke at the time. Another form of "DRM" was not to write anything down ever.  The Celts, unfortunately, were one of the most notorious adherents of this school of protection of IP: they could have done it, as the Celts of France, Britain and Ireland were aware the Romans were writing, but they considered it sacrilegious: the only acceptable way to pass on knowledge was for a young person to learn it by heart from an older person.  As a consequence we know very little about their culture except what was said by the Romans, their enemies.
Answer: Back in the day, in the early 90s, I bought some software whose manual was printed on red paper, which was meant to discourage photocopying on black and white photocopiers. If you photocopied it, it would come out as a big mess because there wasn't much contrast between the print and the background.
Presumably this technique was used elsewhere too.
Comment: The original SimCity had a "red sheet" which was similarly used for copy protection.  Every so often the game would ask you for the population of a certain real-world city, which you could read off a red sheet: https://magisterrex.wordpress.com/2010/10/22/yesterdays-copy-protection-schemes-simcity/
Comment: Film scripts are sometimes printed on red paper to help prevent photocopying (not that it can't be defeated with a scanner and some photoshop work, but it adds a barrier).
Comment: A game I developed had the manual printed in "non-repro blue" (https://en.wikipedia.org/wiki/Non-photo_blue) on white for that reason.
Comment: The game "Oxyd" had a manual with tables that couldn't be copied well back then and in the game where different points where you need to get values from these tables. Also my certificate from school was red paper since i hadn't give back all my books.
Comment: Joined just to upvote this. I'm pretty sure I still have at least one of these in my possession at home. There were pages in the manual with hex codes inked in non-repro blue (as @Rich says). At startup the game would request a semi-random subset of that to be typed in at the keyboard. I understand crackers got around this by hacking the code in the check, or sometimes by including a text file with the text in question.
Comment: @MichaelLugo - I have an original copy of SimCity for the Amiga, and I don't remember that. It might have just been for some platforms? (eg: The *later* release on the PC and C64) Perhaps I'll go check when I get home.
Comment: I'm not familiar with the release history of SimCity, but I had it for the PC.
Comment: I've seen this in the manual of an Ada compiler.
Comment: Many early photocopiers (into the 80s) used green light to better match the photo cell characteristics (https://en.wikipedia.org/wiki/Photocopier#Health_issues). That's why a spectrum of greenish-blueish color wouldn't copy (well), and a spectrum of redish colors would appear (almost) black. I think I have seen documents (like manuals) printed in green but do not recall a specific title.
Comment: I've seen college text books with a similar protection, it had a brown bar across some pages, that would end up having a really bad contrast with the black text, although I guess that you could play with the photocopier settings to try and make the contrast somewhat usable.
Comment: This can happen even accidentally.  My old optometrist cartons are written in light blue ink on dark yellow paper, and was very hard to photocopy with old machines.
Answer: There's another version of DRM that you find in paper reference sources.  (This where the data itself is not subject to protection.)  Deliberately introduced harmless errors.
This does nothing to stop people from copying the material for personal use but it does keep them from copying it for commercial use.
"You say you didn't simply copy my street map.  Please explain to the court how Silly Alley ended up in your map?  As shown by this photograph there is no alley at that location."
Or encyclopedia articles that discuss a person or place that doesn't exist, same concept.
Comment: See also: [fictitious entry](https://en.wikipedia.org/wiki/Fictitious_entry), [trap street](https://en.wikipedia.org/wiki/Trap_streets) and [Agloe](https://en.wikipedia.org/wiki/Agloe,_New_York).
Answer: I'd say that the closest thing to copy protection that's ever included in physical books would be a Trap street.
These are fake elements included by cartographers in maps to catch people illegally stealing their work. Basically, you include a street, town, river, island etc that does not actually exist in a map that you have created, and if you later catch another publisher selling a map that includes that item, you sue them for illegally profiting from your work.
There are a number of interesting examples in this article: The Fake Places That Only Exist to Catch Copycat Mapmakers.
Comment: This is a duplicate of [a preexisting answer](/a/1750).
Comment: Ironic comment, given that this is a question about mechanisms to discourage copying.
Comment: @msh210 Honestly, I must've missed Loren's answer. That said, another answer being the about the same concept shouldn't automatically disqualify it, or call for moderation. The same idea, differently expressed may be a better answer.
Comment: @msh210 - as long as it's not a literal copy/paste, I don't think that it's worth it to delete it. *Downvote*, maybe, but not *delete*.
Answer: I have heard of movie scripts being printed on red or dark brown paper to prevent photocopying on set. Photocopiers at the time only supported full black or white, so if a colour was closer to black, it would become black. Red being closer to black than white resulted in pages being full black. But is different enough to be readable by humans. Not technically a book, but similar.
Of course that wouldn't work now days with modern cameras/scanners.
But modern cameras often see into the infrared spectrum so a layer of something the had a high reactivity for the infrared spectrum might. Cinemas have used bright infrared lights to prevent people recording the movie with a camera. Night vision on cameras is normally implemented with infrared lights. But not all cameras do this. Its probably also not to hard to filter out the infrared light.
It's worth considering that DRM on digital ebooks can still be bypassed using the exact same techniques as copying a physical book. You can scan/photograph the pages on an ebook reader or tablet for example. Of course it's generally quicker to crack the DRM and not have to bother.
In this way DRM just makes it more effort to copy than it's worth for many people. Although some people will bypass it, and you only need one since if they do it then, they can share it with everyone via the internet.
The other thing it does is reduce the quality of the copy. A scanned book might have OCR errors. It might not get formatted the same way. It might be missing metadata like the table of contents. Page numbers might end up in the text. A cam of a movie is bad quality, washed out, bad audio, framerate might be out of sync causing blurred frames. Capping a raw decoded video/audio feed will loose quality when it gets reencoded due to it going through lossy compression twice (that won't apply to lossless codecs, but that's generally only audio).
Comment: Filtering out IR is [not exactly difficult](https://www.bhphotovideo.com/c/product/190037-REG/Rosco_120380007508_Permacolor_Hot_Mirror.html).
Answer: Many video game manuals have forms of copy protection in.
Some games require you to use a lookup sheet from the manual or similar. The lookup sheet is sometimes a decoder wheel (such as in Monkey Island) or printed in a way that is hard to copy (such as in Sim City)
These aren't really copy protection of manuals, however some games spread the copyright across the entire manual. The reason for copying a manual was primarily to bypass the copy protection of the game. Therefore as a sort of copy protection, they would often force you to have to copy the entire manual, which in the 90s was not a simple task as photocopy devices were not as ubiquitous as they are today. Examples are games like Lion King which required you to enter a word from a specific paragraph on a specific page in the manual, and Eye of the Beholder which had a symbol on every page and required you to enter a word from a page matching the symbol.
Both were deterrents to copying the manual by requiring you to copy the entire thing, which was a significant number of pages.
Copy protection through sheer volume is an interesting one, I think! Plus, it stops you from manually writing down the key parts, such as with a single large card, 20 minutes of laborious copying and you could get a key portion of it down.
Interestingly, the Lion King's copy protection could just be brute forced, if you found one word you could repeatedly launch the game and type in that word until eventually it was correct as it loaded quickly and prompted you immediately upon launch. The dictionary it had of page/line/word combinations was very small. Eye of the Beholder had symbols and a much bigger dictionary so it was harder to copy them manually. In addition, it prompted you after you completed the first level, so you couldn't restart the game quickly if you failed to try again.


Do you name controls on forms using the same convention as a private variable?

Question: For some reason I never see this done.  Is there a reason why not?  For instance I like _blah for private variables, and at least in Windows Forms controls are by default private member variables, but I can't remember ever seeing them named that way.  In the case that I am creating/storing control objects in local variables within a member function, it is especially useful to have some visual distinction.
Answer: This might be counter-intuitive for some, but we use the dreaded Hungarian notation for UI elements.
The logic is simple: for any given data object you may have two or more controls associated with it. For example, you have a control that indicates a birth date on a text box, you will have:

the text box
a label indicating that the text box is for birth dates
a calendar control that will allow you to select a date

For that, I would have lblBirthDate for the label, txtBirthDate for the text box, and calBirthDate for the calendar control.
I am interested in hearing how others do this, however. :)
Answer: Hungarian notation or not, I'm more curious if people prepend m_ or _ or whatever they use for standard private member variables.
Answer: I personally prefix private objects with _
Form controls are always prefixed with the type, the only reason I do this is because of intellisense. With large forms it becomes easier to "get a labels value" by just typing lbl and selecting it from the list ^_^ It also follows the logic stated by Jon Limjap.
Although this does go again Microsofts .NET Coding Guidelines, check them out here.
Answer: For me, the big win with the naming convention of prepending an underscore to private members has to do with Intellisense.  Since underscore precedes any letter in the alphabet, when I do a ctrl-space to bring up Intellisense, there are all of my _privateMembers, right at the top.
Controls, though, are a different story, as far as naming goes.  I think that scope is assumed, and prepending a few letters to indicate type (txtMyGroovyTextbox, for example) makes more sense for the same reason; controls are grouped in Intellisense by type.
But at work, it's VB all the way, and we do mPrivateMember.  I think the m might stand for module.
Answer: I came through VB and have held onto the control type prefix for controls. My private members use lower-camel case (firstLetterLowercase) while public members use Pascal/upper-camel case (FirstLetterUppercase).
If there are too many identifiers/members/locals to have a 90% chance of remembering/guessing what it is called, more abstraction is probably necessary.
I have never been convinced that a storage type prefix is useful and/or necessary. I do, however, make a strong habit of following the style of whatever code I am using.
Answer: I don't, but I appreciate your logic. I guess the reason most people don't is that underscores would look kind of ugly in the Properties window at design time. It'd also take up an extra character of horizontal space, which is at a premium in a docked window like that.
Answer:
Hungarian notation or not, I'm more
  curious if people prepend m_ or _ or
  whatever they use for standard private
  member variables.

Luke,
I use _ prefix for my class library objects. I use Hungarian notation exclusively for the UI, for the reason I stated.
Answer: I never use underscores in my variable names. I've found that anything besides alpha (sometimes alphanumeric) characters is excessive unless demanded by the language.
Answer: I'm in the Uppercase/Lowercase camp ("title" is private, "Title" is public), mixed with the "hungarian" notation for UI Components (tbTextbox, lblLabel etc.), and I am happy that we do not have Visual Case-Insensitive-Basic developers in the team :-)
I don't like the underscore because it looks kinda ugly, but I have to admit it has an advantage (or a disadvantage, depending on your point): In the debugger, all the private Variables will be on top due to the _ being on top of the alphabet. But then again, I prefer my private/public pair to be together, because that allows for easier debugging of getter/setter logic as you see the private and public property next to each other,
Answer: I write down the name of the database column they represent.
Answer: I use m_ for member variables, but I'm increasingly becoming tempted to just using lowerCamelCase like I do for method parameters and local variables. Public stuff is in UpperCamelCase.
This seems to be more or less accepted convention across the .NET community.


Why should we consider the output of the AES s-box as a "sensitive value" in relation to side channel attacks?

Question: In general,  we consider the output of s-box in AES as a "sensitive value" in order to perform a side channel attack. I would be very grateful if you could explain to me the reason of that consideration. Why should we consider the output of the AES s-box as a "sensitive value" in relation to side channel attacks?
Answer: I would like to complete poncho's answer by mentioning a point that has not been discussed here.
On top of being an internal state which directly depends on plaintexts (resp. ciphertexts) and the key if you attack the first round (resp. the last one), making hypothesis on S-box output (resp. input) allows to exploit the non-linearity of this operation. Indeed, due to this property, passing the hypotheses through the S-box operation ensures a good distinguishability between the correct and incorrect key guesses.
For example, let's say you are performing a correlation power analysis (CPA) by considering the Hamming weight as leakage model. Then if you choose to focus on the round key addition (which also constitutes an internal state which directly depends on plaintexts (resp. ciphertexts) and the key), then all your key hypotheses which have a small Hamming distance with the good key will also result in a high correlation coefficient. The S-box non-linearity offers the  advantage to reduce the peak for all the wrong assumptions.
Answer: That's because that internal value gives insight to the attacker into the internals of the cipher operation; it can be expressed in terms of known plaintext (or ciphertext) bits, and subround key bits, and can allow the attacker to rederive the subround key bits.
The two simplest examples:

Suppose the attacker can deduce the outputs of a last round sbox (or, if he can't deduce it, isolate which plaintext/ciphertext pairs where a particular last round sbox generates a specific value); what AES does is (essentially) xor that last round sbox output with the last set of subkey bits and output that; the attacker would be able to xor the known ciphertext with those sbox outputs and rederive some subkey bits.  And, if he can do that for all the last round sboxes, that gives him the entire AES-128 key.
Suppose the attacker can deduce the outputs of a first round sbox; what the attacker can do is then compute the inputs to that first round sbox (as the sbox is a known invertible function).  AES xors the first round subkey with the plaintext to generate that first round sbox input; just like the previous attack, the attacker xor's that to recover first subkey bits, and like the last time, if he can do that for all 16 first round sboxes, that gives him the entire AES-128 key.

Middle round sboxes are a bit more subtle, but can also be used by the attacker.
Answer: I can extract the state for any circuit that is not dual rail encoded because a "clock" gives me a snapshot of a power condition.  In practice, this is difficult because systems generally have so many transistors, things fall into noise.  I can pull the top of an IC and tap the power line to the crypto core, but that point, I pretty much can just extract a hardware key.
Assuming the "classical" synchronous circuits, you have a two states for current between "1" and "0".  In the ideal case, the power consumed by these digital states are identical, but practice this is not true.  What the S-Box gives you is an intermediate state where I can look at the power spectrum.  A note on AES, one way to get around this is to expand the S-Boxes in circuits.

Why should we consider the output of the AES s-box as a “sensitive value” in relation to side channel attacks?


Are electrical subpanels safe in the bedroom?

Question: If not, how do you correct it, or can it be moved without making too much work?
Answer: It should be safe as long as you maintain the required minimum distances to flammable materials and don't obstruct access to the panel. That means you can't cover the panel or have it near any wall hangings, curtains, bedding, etc.
You also must keep access to it, which means it shouldn't be behind furniture or inaccessible for some other reason.
As for moving it, that would be a lot of work. It would require rewiring all the circuits that go to that panel, and also rerunning the cable that runs from the subpanel back to your main service panel.
Answer: NEC doesn't mention anything that would prohibit electrical panels in a bedroom. I would still probably have my bed on the opposite wall, just in case. So it's definitely legal.
As for moving it - it might be doable, but most likely will be impractical. Every single branch circuit from this panel would have to rerouted to a new location which will require quite a bit of wall opening.
Comment: My ~40 year old apartment is wired with my panel in the bedroom.  It's on an otherwise unusable section of wall in the space where the main and closet doors swing when open.


How can I determine why my lights flicker when the A/C is running?

Question: My lights considerably flicker whenever a large load comes on in the house and it has been this way since we renovated five years ago. I am attempting to troubleshoot this now and have already probably waited longer than I should have. I did some reading and ultimately removed the cover of the main panel and tested across the two hot wires at the main panel. All circuits were active. The reading I received was 245 +/- 2V, meaning average of 245V but fluctuated between 243V and 247V. I then had my wife turn our whole-house air conditioning unit on and voltage dropped to 237 +/- 1V while AC was running. Is this a normal voltage drop when a large appliance is turned on or is this indicative of an issue?
Comment: Did the voltage stay low the whole time the ac was on, or did it go back up once the ac had gotten started?
Comment: The voltage stayed low the whole time the AC was on.
Comment: What size service do you have? When you renovated, did you add elements to the electrical system that would increase your demand? If so, did you also do a load calculation to include the new demand and upgrade the system if required?
Answer: What, if any work was done to the electrical system when you renovated and the problem started? In addition, what, if any work was done on the house in the immediate vicinity of the electrical service entrance?
Do you happen to own a non-contact thermometer (or know someone you could borrow one from?)
If this is a bad connection (and that's my guess), it will be heating itself (more or less depending on how much current loads in the house are drawing) - ie, if your microwave draws 10 amps, it's heating itself with 20 watts (10A X 2V) when you run that - if your AC draws 30 amps it will be heating with roughly 270 Watts (30A x 9V)
Lacking a non-contact themometer you can sometimes find these by touching the grounded exterior of electrical enclosures and feeling for heat. Having one means you can also look at specific parts inside the panel (but the problem may not be there - it may be in the meter box, which you generally can't open yourself anyway.)
Ideally you'd start at some point when nothing much has been using electricity in the house, or you've actually shut off the main for several hours, go around and feel/measure temperatures, then turn on the power and turn on as many loads as possible and feel/look for an area that is getting much warmer than the rest of the wiring/enclosures.
Since you are evidently comfortable in the open service panel, you can also check for voltage differences between the incoming wire and the terminal it connects to, and/or see if the voltage you measure is very different (under load) if measured from terminal to terminal or from incoming wire to incoming wire. That checks that end of the meter-to-service cables - the other end you generally need an electrician or the power company to check.
It is important to find and solve this issue before it gets worse; you're in the early stages of "how electrical fires get started" IMHO.
Comment: I used "renovated" very liberally. We actually replaced the house rebuilding on the existing foundation. The entire electrical system is brand new, including from the telephone pole to the house.
Comment: Right. So, on the one hand, all connections were new, and on the other hand, they **should** all be up to snuff, size-wise, etc. So you definitely have a problem here, and my bet remains with "bad connection somewhere" though I suppose it's possible there's an undersized aluminum wire outside the house where code permits the utility to pretty much suit itself, and cheap is what suits them all too often.
Answer: The fact that the voltage drops that much at the main leads pretty well says it is a power delivery problem upstream of there.
There are only a few components it could be:

wires from the breaker panel to the power meter base
the meter socket
the meter itself
wires from the meter base to the transformer
transformer taps
the transformer itself
the feed upstream to the transformer

If you have other neighbors sharing your transformer, measure one of their voltages while you turn on and off your load.  If there is similarly significant voltage variation, the problem is clearly with the utility.  If their voltage is steady, the problem is between the transformer and your breaker box.
As far as I know, the electrical utility usually owns and is responsible for all of these but the first two (meter socket and the wires from the meter base to the panel).
You could try giving the meter a wiggle to make sure it is fully seated in its socket—especially if the meter was removed during the renovation.
Call the utility to check their connections and voltages up to the meter base and the meter itself.  Since they will pull the meter to do this, try to be there to inspect the connections to your wire to the panel.  Maybe the tech will measure its resistance for you.
Answer: It's tough to say for sure without seeing the setup and troubleshooting further but it could be a sign of a bad connection (corroded, loose, damaged, etc.). Does this occur only on some circuits, or the entire house? This will give you an idea of where the issue is - if its all circuits then its likely between your panel and service.
Something to watch out for is if the lights get brighter or the voltage jumps up (you'll only notice this on 120V circuits). This is a sign of an open neutral which can be very dangerous and likely requires a licensed electrician to help troubleshoot.
Comment: @Steven - All wiring, mains and service entrance wires included, will have some series resistance. This means that there may very well be a measurable voltage drop whilst an appliance is running. The amount of drop depends on various factors including wire size, length of wire runs, amount of current drawn through the wire, temperature of the wiring and the quality of interconnections between wires, outlets and circuit breakers. So it is not correct to say that no voltage drop would be observed while an appliance is running. The amount may be small but it will be there.
Comment: Thanks @MichaelKaras.  I've removed that part of my answer.
Comment: Thanks, Steven. I did see a constant drop. I've also observed this when monitoring voltage at an outlet and then turning on the microwave (separate circuit). The voltage at the outlet dropped from 120V to 118V and held at 118 while the microwave was running and then jumped back up to 120. I have never seen the lights grow brighter, only dimmer when loads are added to the system.
Comment: Is all of your wiring copper?  Only reason I ask is that if there aluminum wiring, there is a higher chance of corroded connections
Comment: However, this seems like a SIGNIFICANT drop, especially with a relatively small load like a microwave causing a 2V drop on a different circuit. That and the timing being "since we renovated" smells a LOT like a bad connection somewhere.
Comment: @Ecnerwal Don't know what type of microwave you have, but mine is rated at 12.5 amps (1500 watts).  Seems like a significant load on a 15 or 20 ampere circuit.
Comment: ...and insignificant (or it should be) on a 200A main (or even a little old 100Amp main.) This thing is dropping voltage ~1.6% on **other circuits**, meaning the drop is on the main feed. No way that's good for a microwave, whether it's 10 amps or 12.5 amps...
Comment: I had a similar problem (Toronto, Ontario), finally traced to a slowly dying cartridge fuse, in one hot line from the pole to the house, just before the service mast.
Answer: Add a capacitor across the lines feeding the A/C unit. The capacitor will discharge in an effort to maintain the original voltage level when the A/C equipment starts. This should improve if not completely eliminate the problem.
Comment: Hello, and welcome to Home Improvement. Adding a random capacitor across the line will almost certainly end in tears or worse; would you be more specific? And, you should probably [take our tour](//diy.stackexchange.com/tour) so you'll know how best to contribute here.


Does Mac-OS Snow Leopard come with a Exchange client?

Question: Does Mac-Os come with a client to connect to exchange.
If not, is Outlook 2007 available for Mac-Os?
Regards,
Answer: Mail.app and iCal and Address Book can connect to exchange servers out of the box in snow Leopard.
Outlook was supposedly going to come to OS X but I haven't heard anything about it in a while.
Comment: re Outlook - it's replacing Entourage in Office 2011, so it is making a return.
Answer: The is a way to connect to exchange from OS X for both calendar and email - both for SNow Leopard and the older OSs.
Here and here are more details for Snow Leopard.
I have used both email and calendar from exchange on the Mac. The presentation is in the "Apple Way" that is quite different than Outlook. There are two separate programs, Mail and Calendar, vs the unified organizer that Outlook is supposed to be (or fails to be, depending on your view)
The existing Mac Office has Entourage. Microsoft recently release Entourage Web Services Edition, which is kinda an Outlook client and syncs both with Exchange and Sharepoint.
The next release of Office, due later this year, will have a full Mac Outlook client that is on peer with the Windows version.


Why does my Sigma 10-20mm EX autofocus freeze up, and the camera won't shoot?

Question: When using a Nikon D7100 and Sigma 10-20mm 1:4-5.6 EX DC HSM, the lens locks up or refuses to shoot. This lens doesn't have a Manual Focus or Autofocus button/switch. This lens is in brand new condition and has been rarely used. I bought it new a couple of years ago. I can fire off maybe 4 shots then change the settings, (A, ISO or speed) and it won't do anything. I'll press the trigger all the way down and nothing happens. I read online that if I take it off the camera, manually turn the focus ring in and out then remount it it will work. After trying this it does help but it freezes up shortly after. Any help would be appreciated. Thanks!
Answer: The Sigma 10-20mm 1:4-5.6 EX DC HSM is a design introduced in 2005.
Your Nikon D7100 was introduced in 2013.
Thus, Sigma had no way to test the design of that lens to see if it would work with the D7100.
This is all based upon the way that third party lens makers design lenses for other manufacturers' cameras. They do not usually license technology from the camera makers. Instead, they "reverse engineer" the camera maker's protocols by obtaining examples of cameras and lenses and measuring how they work. They measure the signals moving between the camera and lens. They may try to extract code from the camera or lens' data storage components. Eventually they try to produce a lens that can "understand" what the camera sends to the lens and can "mimic" what the camera maker's lenses send back to the camera.
They then test their prototype lens on each of the camera models available from the camera maker at that time. They have no way of testing their new lens with camera models that will be introduced in the future.
The main issue that sometimes comes up with this approach is that the camera makers may not utilize all of the code contained in their protocol with every camera and lens model currently on the market. They may have certain pieces of code included that are reserved for future use with cameras and/or lenses currently under development. They may have code intended for projects they hope to do even further into the future that may or may not ever come to fruition.
If the camera maker starts utilizing some of this "hidden" code in products produced after the third party lens was "reverse engineered" it can often have detrimental effects on the functionality of the older third party lens used with a newer camera body. Sometimes lens makers have subsequently updated the firmware for an older lens to make it compatible with newer camera bodies. This required the lens to be sent to a service center for the lens' memory chips to be swapped out or reflashed (overwritten with the new code). Newer copies of the lens made after the newer camera models were introduced may or may not have had the newer firmware when shipped, and of course older copies of the lens that have been sitting in a retailer's inventory for several years would not have the update if sold after the newer firmware had been released.
Lately, though, some lens makers have started to make it possible for the end users of third party lenses to update their lenses themselves via a "dock" that attaches to the lens camera mount and connects to a computer. These docks only work with newer lenses that are designed to allow them to communicate with the dock. Tamron calls their dock and software system the "TAP-in Console" while Sigma calls their dock the more mundane "USB Dock" and the software is named "Sigma Optimization Pro."
Unfortunately for owners of older lenses such as the Sigma 10-20mm 1:4-5.6 EX DC HSM, the new docks only work with lenses that are specifically made to be compatible with these USB docks and were introduced at around the same time or after the introduction of the docks. Sigma introduced their USB dock system in May of 2013 and it is compatible with their 'Global Vision' series of lenses that include models in the 'Art', 'Sports', and 'Contemporary' lines.
At one time Sigma offered a firmware update to the early examples of your lens (later copies made after this issue was known and resolved got the updated firmware when they were made) to make it compatible with the D5300 and similar newer Nikon cameras. They did this at no cost for lenses under warranty and for a minimal fee (about £40 in Belgium in 2016). The owner was responsible for shipping the lens to a Sigma Service Center. You should contact the Sigma Service center for your geographic location and inquire if that update is still available.
Comment: Michael C. I appreciate the technical and detailed answer. Thank you.
Answer: It is weird because Sigma either make lenses whose firmware can be updated by the user or makes lenses using the lowest common denominator (in protocols) of the camera manufacturer.
And also Nikon, I would say always carries over the protocols from the oldest camera/lenses to the new bodies (backwards compatibility). One of the things that differentiates Nikon from Canon is that you can use from a slightly modified 1950 Nikkor film lenses to the latest digital ones on its newest DLSR bodies.
Does your lens have something similar to a quite big screw that camera moves to focus. If it has that you will need pro-am Nikon (old or new) to drive the autofocus, it was a system used in the first couple of generations autofocus cameras and lenses and was carried forward only for the pro-am DSLR, in most of the amateur line it was dropped due to cost constraints.
It flys with a new D500 (DX) pro-am and your body... your problem is probably that one of the few lenses that shipped with faulty firmware and it needs to be reflashed at a Sigma service center. Check DPREVIEW forums and the review of that lenses with your DSLR body in DXOMARK to see if reflashing is worth it or not.
Comment: This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post. - [From Review](/review/low-quality-posts/63806)
Comment: The firmware was not "faulty" when it shipped. It was, at worst, incomplete for use with future Nikon cameras. It's no great mystery about which lenses can be updated by the user and which can't: Since introducing the USB dock, pretty much all of the new lenses they've introduced (which are pretty much all *Global Vision* series lenses) are compatible with the dock and accompanying software.
Comment: Nikon chose to make their "new" AF cameras back in the late 1980s as compatible as possible with their existing mount. Canon chose to make a clean break and create a new all electronic mount in 1987. By the mid-1990s Nikon had lost the market dominance they had held for decades as the capabilities of the all electronic connection became obvious. It took Nikon almost three additional decades to introduce lenses with electronically controlled apertures that are [more consistent from shot-to-shot than mechanically linked/actuated apertures.](https://photo.stackexchange.com/q/60591/15871)
Comment: But it was the ability of the all electronic connection to exploit the advantages of Ultrasonic AF motors in the lens (designed to be optimal for each lens' unique focus parameters: length of travel, weight of moving focus elements, etc.) and the precision with which the focusing elements could be controlled that put Canon into the number one position in the market by the mid-1990s, where they have remained ever since. By the time Nikon introduced their first in-lens Silent Wave Motor, it was all over but the crying in terms of what brand most PJs and sports/action shooters were using.
Comment: @xiota It was neither a critic nor a request for clarification. It's a proper answer that explains Nikon policy about it's own lenses, I have D850 (which still have the mechanical screw to enable AF in lenses without an internal focusing motor and still shoot with some AI primes.  Not all the Sigma 10-20mm 1:4-5.6 shipped need a firmware upgrade, only a few of them were shipped with the faulty firmware. Next none Nikon lenses are firmware upgradable by the user and all the Nikkor lenses concurrently shipped with that Sigma did not a firmware update to be compatible with newer bodies.
Comment: I thought this was off-topic (and almost voted to remove) but noticed the last paragraph does mention that it may need to be refreshed with newer firmware.


Why do transition elements make colored compounds?

Question: Why do transition metals element  make colored compounds both in solid form and in solution? Is it related to their electrons?
Comment: **it is due to d-d transition and charge transfer spectra**
Answer: You are absolutely correct, it all about the metal's electrons and also about their d orbitals.
Transition elements are usually characterised by having d orbitals. Now when the metal is not bonded to anything else, these d orbitals are degenerate, meaning that they all have the same energy level.
However when the metal starts bonding with other ligands, this changes. Due to the different symmetries of the d orbitals and the inductive effects of the ligands on the electrons, the d orbitals split apart and become non-degenerate (have different energy levels).
This forms the basis of Crystal Field Theory. How these d orbitals split depend on the geometry  of the compound that is formed. For example if an octahedral metal complex is formed, the energy of the d orbitals will look like this:

As you can see, previously the d orbitals were of the same energy, but now 2 of the orbitals are higher in energy. Now what does this have to do with its colour?
Well, electrons are able to absorb certain frequencies of electromagnetic radiation to get promoted to higher energy orbitals. These frequencies have a certain energy which correspond to the energy difference between different orbitals. Now most substances are only able to absorb frequencies of radiation which are outside the visible light spectrum, for example they might be able to absorb radiation which has a frequency of $300$GhZ (that is infrared radiation). This means that it reflects all other types of radiation, including the full spectrum of visible light. So our eyes see a mixture of all the colours; red, green, blue, violet, etc. This is seen as white (this is why several organic compounds are white).
However transition metals are special in that the energy difference between the non-degenerate d orbitals correspond to the energy of radiation of the visible light spectrum. This means that when we look at the metal complex, we don't see the entire visible light spectrum, but only a part of it.
So for example, if the electrons in an octahedral metal complex are able to absorb green light and get promoted from the $d_{yz}$ orbital to the $d_{z^2}$ orbital, the compound will reflect all other colours except for green. Therefore by using the colour wheel, we can find the complementary colour of green which will be the colour of the compound, which is magneta.

This explains why not all transition metal complexes are colourful. For example copper sulfate is a bright blue compound, however zinc sulfate on the hand is a white compound despite being a transition metal. The reason behind this is because zinc's d orbitals are completely filled up with electrons, meaning that it is not possible for any electron to make a d-> d transition as they are all filled up. Hence you might sometimes see zinc referred as not being a transition metal.
Comment: Won't the electrons emit the light in the same frequency as it absorbed when it comes back to the ground state?
Comment: The crystal field theory is deprecated, but what you describe is also valid for the ligand field theory, which should be used instead now.
Comment: Then how come KMnO4 has color (a very deep purple)? The manganese would have an oxidation state of 7-, which means the atom would no longer have occupied d orbitals at all.
Comment: A broader question: How does crystal field theory apply to transition metals that are part of polyatomic ions?
Comment: Nanoputian, the complementary colour explanation works, but the comment above asks a good question. Is it that the electron excitation-deexcitation method of explaining this just doesn't work?
Comment: @GovindBalajiS https://chemistry.stackexchange.com/a/99638/108785
I hope this answer by some other user answers your query.
Answer: The partially full d-orbitals in transition metals have energy splittings that happen to lie in the visible range.  Depending on the arrangement of substituents (known as ligands) that attach to them, the electron energies split according to crystal field theory.  Similar splitting in the s or p orbitals produce gaps in the ultraviolet, and any visible light goes right through, so we don't see any color.  In transition metals, however, visible light excites the electrons from a lower d orbital to a higher one and only letting some light through.
Comment: A perhaps deeper explanation for the first sentence in your answer can be found [in this article](http://depa.fquim.unam.mx/amyd/archivero/LecturasobreNodosRadiales_12854.pdf). It seems that the fact the 3d orbitals are anomalously compact explains why many electronic transitions in fourth period d-block metal complexes are in the visible region.
Comment: Because of the [Pauli exclusion principle](https://en.wikipedia.org/wiki/Pauli_exclusion_principle) that says that two electrons can't be in the same place at the same time. For the transition to take place, an electron has to move from a lower split level to a higher split level. If there is no empty spot, no transition can take place.
Comment: Why can't electron transition take place between fully filled split d orbitals?
Comment: How we are sure that the color doesn't come from the transition between p (filled) to s (empty) orbital?
Answer: Transition elements have partially filled d orbitals. We also know that when electrons jump from one orbital to another light is emitted due to which the compounds of transition elements seem to be colored compounds.
Note: This can also happen in some organic compounds though in this case, it is p orbitals and not d orbitals.
Comment: In case of transition metals ($3d$) why we can't have a transition from $4s$ to $5s$ where would be in the visible range?
Comment: Firstly, in complexes usually the 4s electrons are removed to form the central positive charged ion. Secondly, the energy gap between the 4s and 5s orbitals is extremely high that visible light photons does not have enough energy to overcome. Such transition would requre photons of at least ultraviolet light. And we are not supposed to see ultraviolet light. In short, it is theoretically possible for a 4s-5s transfer, but we cannot see it.
Answer: Colored compounds of transition elements are associated with partially filled (n-1)d orbitals. Tthe transition metal ions containing unpaired d-electrons undergoes an electronic transition from one d-orbital to another. During this d-d transition process, the electrons absorb certain energy from the radiation and emit the remainder of energy as colored light. The color of ion is complementary of the color absorbed by it. hence, colored ion is formed due to d-d transition which falls in the visible region for all transition elements.