AdS/CFT not dependent on validity of string theory

Question: I have been told that the AdS/CFT correspondence proof does not rely on the validity of string theory. To be honest I don't know what to make of this. The idea of taking seriously the results of applying the techniques of this correspondence is appealing, but before I head in that direction, I need some help finding any references that actually make clear the fact that such a correspondence is independent of the validity of string theory. I am also curious as to the original explicit derivation of the correspondence. I just want to be able to really learn and truly believe the results myself before considering working applying its results.
  I'm not contesting results of any kind, I just want to know this stuff well.
Comment: Here you go, for the original 'derivation': http://arxiv.org/abs/hep-th/9711200
Comment: You might want to look at http://arxiv.org/abs/1308.1977 by Don Marolf. However, to my knowledge, such a line of reasoning is not well-established (with much lesser evidence than stringy arguments).
Comment: An interesting example: Vasiliev theories in $AdS$ are holographically dual to theories on flat space. [Minwalla and co.](http://www.hri.res.in/~ism2012/talks/Minwalla.pdf) showed that in some particular cases, these Vasiliev theories can be made out as a limiting case of string theory. I don't think it is known whether this holds in general. Then again, string theory has this tendency to crop up in places where you least expect.
Comment: I am not sure if higher-spin theories can be embedded into string theory. First of all these dualities exist in any dimension, in particulat in d much greater than 10. Secondly they do not rely on SUSY at all, though one can introduce SUSY versions. Thirdly, Minwalla et al. gave some very general words for $4/3$ duality and string theory, but these are just words and they rely on particular dimension and $N=6$ SUSY and there is no stringy explanation without SUSY even in their version.
Comment: This presentation by Juan seems to distil some of the conceptual basis for the duality http://www.youtube.com/watch?v=50-WpB14OMo
Answer: There is no doubt that the gravitational theory in the AdS space equivalent to the CFT on the boundary is string theory with all objects, effects, and interactions that string theory predicts, and this fact has been reflected in all the AdS/CFT literature since the very first Maldacena paper. This shouldn't be surprising because string theory is the only consistent theory of quantum gravity, at least in $d\gt 3$.
Maldacena derived the two sides of the duality as decoupling limits of the dynamics of D-branes in string theory and/or the dynamics in their near-horizon limit. No other controllable, non-stringy context is known that would allow one to prove that the limits are decoupled.
BMN (Berenstein-Maldacena-Nastase) is the most explicit proof of the presence of excited strings and their interactions (see e.g. this) from the CFT. Detailed knowledge is available for the presence of the stringy wrapped branes (baryonic operators, Witten) and many other objects in the theory. The stringiness of AdS/CFT is also reflected by a class of AdS/CFT examples that involve (conical) Calabi-Yau compactifications of string theory and by the correct $d=10$ or $d=11$ of all the known rigorous supersymmetric examples of the AdS/CFT duality.
There exist examples of AdS/CFT that are not constructed out of the usual critical superstring, for example the minimum "pure gravity in 3D" which is dual to a 2D CFT involving the monster group as a symmetry; or the Vasiliev theory. However, one may view such vacua as examples of irregular compactifications of string theory, too.
There are also many known derivations, especially of the black hole entropy, that only rely on some general algebraic features of the CFT but not on their stringy origin. This fact changes nothing about the fact that a fully consistent theory of quantum gravity in any working AdS/CFT pair has to obey additional consistency conditions which are linked to string/M-theory.
Karl-Henning Rehren's "holography" mentioned in another answer is a vacuous pseudoscience that has nothing to do with the depth of the actual holography in quantum gravity. What is done in that paper is just rewriting fields $\phi(x^0,x^1,x^2,x^3,x^4)$ as $\phi_{x^4}(x^0,x^1,x^2,x^3)$ i.e. rewriting one of the coordinates as an "index" of the fields, and claiming that coordinates may be reduced by one (or any number, for that matter). However, nothing changes about the physical "number of dimensions" by this sleight-of-hand.
Some more comments about the unavoidable stringiness of AdS/CFT here:

http://motls.blogspot.com/2014/01/quantum-gravity-in-adscft-is-inevitably.html?m=1
Comment: Voted down because of the unscientific and misleading sentence "string theory is the only consistent theory of quantum gravity", rather than the more humble version 'string theory is the best candidate for a consistent theory of quantum gravity'.
Comment: It is not a misleading sentence, it is a very important result of modern scientific research. Science is not about being humble; science is about finding the truth about Nature. We are not saying that the Earth's mass is about 99 kilograms just to be humble.
Comment: Good scientists are almost always humble when it gets to things they do not fully understand (at least that is what I have learned). "Earth's mass" is a significantly better understood problem, than Quantum Gravity.
Also, being humble is not about reporting numbers (incorrectly) less than what they are; it is about not claiming more knowledge (or comprehension) than we really have.
Comment: Science never understands some phenomena "quite fully" but it often understands them vastly better than non-science or less developed science. Whether some scientists are humble is about their personality and has nothing to do with the scientific validity of their claims. Otherwise, your claim that good scientists are "almost always humble" is a historical lie. Almost all great scientists were highly self-confident and assertive, starting from the founders Newton and Galileo and continuing with tons of other - Feynman, Zwicky, I could say hundreds - were self-confident if not "arrogant".
Comment: Otherwise it is logically fallacious for you to say that the proposition "string theory is the unique consistent theory of quantum gravity" is less humble than your proposition about a "best candidate" that boldly suggests that there are other candidates. Claiming that there is another possible consistent theory of quantum gravity is an *extraordinary* claim that would require extraordinary evidence to be taken seriously. Many people have said such a claim but all of them were quickly shown to be wrong.
Comment: I completely agree with your "Almost all great scientists were highly self-confident and assertive" when speaking about things they understood well, but I still think they were humble when it got to things they didn't comprehend.
And when you say "no alternative theory [to string] is mathematically possible", it means string theorists are somehow close to showing that every consistent theory of quantum gravity has a Hilbert space isomorphic to that of string theory; I don't think we are anywhere near proving such statements.
Comment: Actually, I take back that almost all great scientists were humble when it got to things they didn't comprehend; the counterexample that comes to my mind is the numerous harsh criticisms against renormalization, in the pre-Wilson era.
Comment: Such self-confidence or even combativeness was often essential for scientists to have achieved what they have achieved. ... We don't know everything about quantum gravity i.e. string theory but we surely do know that no other, truly non-stringy (from string theory disconnected) consistent theory of quantum gravity above $d\gt 3$ is known and there is very strong evidence that no such an alternative theory is mathematically possible.
Comment: @LubošMotl For your information, in your third comment, there shouldn't be an article (an) after 'no' in "no such an alternative" xD my respects
Comment: [Here](http://www.quora.com/What-are-if-any-the-stringy-effects-seen-on-the-fluid-dynamics-side-of-the-gravity-fluid-dynamices-correspondence) I have a potentially very dumb follow-up question to the nice TRF article ...
Comment: @Luboš Motl, I have tried to put some time to the ads/cft papers listed, but I think I need some more string background. Are there any  explicit(at least in derivations and clarity) texts that are not so long, that you can recommend personally for me to look at, or perhaps a series of papers. I am aware of some of the standard texts, but I am curious about your personal opinion on the matter. My background is just almost good enough to pick up a specific topic in qft and study, but I am not any sort of expert in the formal sense.
Comment: Apologies, there are so many choices. This is like a rather difficult job of an advisor you want. I could mention some random good enough papers but I doubt we would achieve something by that. It would be like telling you to pick some papers at http://scholar.google.com/scholar?q=ads-cft&hl=en&lr=&btnG=Search
Comment: @Luboš Motl, I completely understand. I downloaded a few papers that seem to be going well so far. scholar.google.com/ does have some great standard texts on the matter as well. I'm a bit surprised.
Answer: The logic of AdS/CFT is independent of string theory, but one finds that the theories that have sensible AdS duals have a stringy character. You could hope to derive from conformal field theory that quantum gravity in AdS is stringy. A "bottom-up" way to think about AdS/CFT (see here, and references therein, for a recent treatment; also this slightly less recent paper) is that conformal field theories satisfying certain conditions (roughly, having a large-N approximation and having a gap in the spectrum of operator dimensions) have correlation functions of low-dimension operators that can be approximately calculated in a perturbative way. These calculations map precisely onto low-energy effective field theory calculations in AdS space. (This low energy field theory includes gravity, because the map tells you that the stress tensor $T_{\mu \nu}$ in the CFT becomes the metric $g_{\mu \nu}$ in AdS.)
More generally, you can think of any CFT, even if it doesn't admit such a perturbative description, as a quantum gravity theory in AdS space, because they have the same symmetries and you can always map one language to the other. For many CFTs the AdS description will be strongly curved and not very useful.
None of this logic refers explicitly to string theory. But once you think about CFTs with a weakly coupled AdS description, you find that you need some sort of $1/N$ expansion to make sense of the theory; otherwise, you don't have a sensible perturbation theory. Having a $1/N$ expansion essentially means you can talk about a state with a well-defined number of particles in AdS. The particles in AdS are single-trace operators in the field theory: e.g., in a gauge theory, you might have operators that look like ${\rm tr}(\phi^\dagger D_{\mu_1} D_{\mu_2} \ldots D_{\mu_n}\phi)$. The basic logic of AdS/CFT tells you that such "long" operators are massive states in the bulk. Longer and longer traces look like more and more massive excited states. In concrete examples, these turn out to be described by string theory: long operators are long strings.
So the way that I would characterize the situation is this: we have a vast number of examples of AdS/CFT originating in string theory. We also have a general understanding of why AdS spaces and CFTs are equivalent to each other. This general understanding tells us that the theories that can be treated as weakly-coupled gravitational theories in AdS all have states described by stringy-looking traces. I don't think we're at the point yet where we can say that this proves that every quantum gravity theory in AdS is a string theory, but it is strongly suggestive of that (as Lubos said, even some of the theories that don't look like string theory at first turn out to be connected to it).
Comment: I went through your references a few times, I am pretty sure I still don't understand Mellin amplitudes, but the logic of both papers seems pretty sane
Answer: Ok, it is important to make some observations here otherwise people will believe all sort of nonsense (mainly the nonsense in Lubos Motl's answer). First: Heavy Ion scattering. AdS/CFT does NOT offer an acceptable answer free of ambiguities.
Viscosity of the Quark Gluon plasma is not observable. The elliptic flow is observable and the observed values are consistent with lots of ideas about what happens at a fundamental level. We do NOT have an accurate value for the internal viscosity and when facing scaling problems AdS/CFT fails "dramatically". For me this is evidence enough that nature does not take AdS/CFT for granted, quite the opposite... Why, this is the main reason (and yes, it is experimental) to consider AdS/CFT unsuitable for describing reality... another subject that in honest conditions should be largely ignored or the subject for abstract mathematics. Second, string theory and AdS/CFT have some things in common but they are not one the cause of the other despite some proofs regarding one done by the use of the other. A set of axioms is not always unique. You can prove different things using aspects from different domains of science and come up with the same result. This doesn't mean (not even remotely) that the truth lies within the set of axioms you like most. Let me be more clear about this: AdS/CFT is not a duality of nature. Natural space is not AdS and natural field theory is not CFT and it never can be exactly in that way. The duality is allowed to explain some situations when strong interactions are relevant and when CFT is relevant (critical points, etc.). The duality does that in a non-unique and ambiguous way and it fails in giving the right (holographic) scaling by orders of magnitude. It is simply to weak to account for real life data and it is NOT a duality of nature. No, you are not allowed to renormalize in that way so the problem is not easily solved and the fact that the predictions do not scale is fatal. However, if AdS/CFT were a duality of nature then string theory would be non-realistic too. Why? simple: because if the duality were to be exact and fundamental gauge theory on the CFT part would be undistinguishable from some strings in the bulk it is known that two isomorphic theories are not to be considered as different. A perfect string/gauge duality would mean strings lose their significance as "fundamental objects". This happens indeed but not because of the exactness of AdS/CFT... String theory could be useful in some cases as for example dimensional extension and reduction procedures are but strings are NOT fundamental in any form and any assumption that they are is against all experimental evidence.
Comment: As a remark: whenever you hear anyone claiming strange things ask yourself: is the proof including conditions like existence and unicity? Is the experiment unambiguous in both directions? Is he/she hiding something? What is the parameter space of the experiment? How do the parameters correlate to each other? Is the "basic assumption" the only one possible? If your answers are "no" or "I don't know" then simply think more about it before jumping to the conclusions. String theory is certainly not "the only game in town" mainly because it is based on non-unique and not necessary assumptions.


What distros are NOT affected by the new Code of Conduct?

Question: What distros of Linux or Unix based operating systems are NOT subject to the new code of conduct recently implemented for Linux? And/or which use no code affected by this CoC?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8a104f8b5867c682d994ffa7a74093c54469c11f
https://lulz.com/linux-devs-threaten-killswitch-coc-controversy-1252/
https://hub.packtpub.com/linux-programmers-opposed-to-new-code-of-conduct-threaten-to-pull-code-from-project/
I have asked this elsewhere and been called trolling, so just to clarify, I am GENUINELY interested in finding out which distros will not have essential code pulled out, rendering them useless. I am simply looking for a stable unix/linux based OS. I have been using A variation of ubuntu for years but as the above articles should explain, this is not trolling or spam, I have a genuine concern about the short and long term functionality of Linux based operating systems.
Comment: You're asking this under the assumption that claims in these threats are true to begin with. [SFC says they aren't.](https://lwn.net/Articles/766784/)
Comment: well that's reassuring, but for the sake of argument, if it were a feasible threat, what distros would be unaffected?
Comment: "_Is there a Linux distribution that doesn't use the Linux kernel?_"... am I understanding you correctly?...
Comment: @Attie, that actually isn't so off-the-wall.  Check out https://en.wikipedia.org/wiki/Comparison_of_operating_system_kernels.  Several, like HURD and FreeBSD, are used in what would still be referred to as "Linux" distros.  :-)
Answer: The Code of Conduct document is real.  The initial "scare" about the world as we know it ending is not a likely scenario.  As grawity linked to in a comment, it looks like contributors don't have a legal basis to pull their code.  What will happen as a result of the CoC is anyone's guess.  It could still have a chilling effect, where some top contributers stop contributing.  Or, the CoC could end up being modified so that it is no longer an issue.  People can only speculate.  However, it could potentially affect Linux in some negative way, at least temporarily, which still leaves your question.
We can look at your question from the perspective that if something negative does happen as a result, would certain distros be unaffected, or less affected?
There are substantial differences in "classes" of distros.  At one extreme are bare bones operating systems, with little more than some basic tools and a terminal.  At the other extreme are distros that are intended to be a user-friendly work environment out of the box.
The world of Linux contains in the hundreds of thousand of modules of code.  Within each class of distro, each distro is like a menu at a Chinese restaurant, "two from column A and one from column B".  It is a selection from the available modules that enable each function to be accomplished; a kernel, a collection of hardware drivers, a package management system, a collection of system utilities, a user interface, maybe a bundle of applications software, and so on, plus all of the libraries and component modules all of those things depend on.  In a fully loaded distro, there can be in the thousands of code modules.
How you might be affected if one or more of those modules was affected depends on the module.  The module could relate to something you don't even use, or it could be central to your operating system, or anything in between.  We also can't predict the nature of the impact, or how it would be mitigated.
Because of the way most things in Linux are tested before release, if you stuck with stuff from the distro's repositories, you wouldn't likely experience critical failures.  Any fallout from the CoC would more likely manifest as slower availability of improvements and features, and perhaps fixes for existing bugs.
When you pick a distro, you first need to select a "class" or type.  If you're a pro, you might want a bare-bones distro that you specify and build yourself almost from the ground up.  If you're a novice, that isn't practical, so you need something much more complete and ready to use.
Once you define the class of distro you need, there are lots of alternatives to pick from.  But all of those qualifying distros will have more or less similar complexity in terms of the number of code modules they contain.
If we assume that whatever impact the CoC is going to have will be random, we can't predict what types of code modules will be affected, or which ones will be affected.  In a general sense, users of bare bones distros will have fewer code modules that could potentially be affected.  However, you can't really pick a distro on that basis; you need whatever level of functionality you need.  Within whatever class of distro is appropriate for your needs, they will all have similar risks.
Bottom line:

No distro would be immune.
Bare-bones distros have fewer code modules that could be affected, but that isn't likely a useful fact.
Within whatever class of distro that will meet your functionality needs, all of the distros will have essentially the same degree of risk.
Even worst case risks aren't likely to manifest in a way that would seriously affect you as an end user.


How to install windows application and SQL server on the client machine?

Question: I want to install my c# windows application on a client place which does not have .NET framework or SQL server. What files do I need to install in order for the application to work with database and how to create a package?
Comment: Install the Exe and copy the database mdf and ldf files in the client place to work.
Answer: Create a setup project from Visual Studio and specify in the prerequisitesto include .NET framework and SQL Server Express. these packages will then be included in the setup or I think you can also specify to download automatically on setup execution.
Answer: You can use ClickOnce deployment for this. With ClickOnce you will give the client an install package that can check for prerequisites and install them if neccesarry. The .NET framework and SqlServer express can be installed this way.
Check the following link for more info: ClickOnce


Changing emotions when a user going to unsubscribe newsletter? Is it good practice?

Question: Is that a good idea to make a response regarding user actions like this one? When user about to unsubscribe changing the face to sad and when click cancel makes face happier. Is it good practice?
https://newtodesign.com/unsubscribe-animation/
Answer: Not necessarily a "good practice" as the only result would be to reduce drop-out-rate, so it does not provide any benefits to the user but it would also not bother him if this doesn`t tip over to become a dark pattern.
Comment: Best would probably be to present users something like a coupon at this stage to keep it positive, if the business wants to desperately hold on (although the user probably already made up their mind).
Answer: An added value to avoid to use them is to think about cultural differences among global online users and keep in mind the international usability testing meaning. Not everyone reads the emoticons in the same way, so I would avoid to use them otherwise if really want to use let them match with the user's cultural background.


Trouble with Camera settings

Question: My lens Nikon AF 85mm 1.8 will only focus at 22 otherwise I get a fEE flashing on the top display. Any suggestions? I use a D80.
Answer: With the D80 you need to set the lens to f/22 and lock it there, then use the controls on the camera body to adjust aperture. This applies to any AF-D lens that has an aperture ring on the lens. Set it to the narrowest aperture and lock it with the little orange switch. You can't adjust the aperture with the lens ring when it is attached to a D80, you must use the camera controls.

Trouble with Camera settings


Recaptcha statistics

Question: Of late recaptcha images have become excessively difficult to decipher. Is there any way to get analytics on unsuccessful attempts before a successful one for your website? I'm pretty certain the numbers are going to be bad and something needs to be done about it.
Answer: If you use reCAPTCHA, you can use their API to log the number of failed attempts (code shown uses the reCAPTCHA Ruby gem):
<code>if validate_recap(params)
      #user validated the captcha, create an account
else
      #user failed to validate, log the attempt and show a new captcha
end
</code>
Using the reCAPTCHA library helps digitise books while reducing scripted signups, so it's worth sticking with it, but if you're worried that its affecting signups and want an alternative, you might consider using Mollom, Akismet, or Defensio, all of which attempt to grade form input to assess whether its human or not.

Recaptcha statistics


Decomposing multiple poisson process

Question: Assume a time series composed by many recurring events coming from many different poisson process each with a different rate. Lets assume for simplicity no overlap between events. Is there any math/statistical tool to decompose the given time series and get the various poisson processes. Ideally like fourier analysis can yield the harmonics composing a periodic signal, the tool should provide a list of poisson processes composing the whole sequence.
Comment: My first impression is that you can't.  The sum itself will be Poisson$(\lambda)$, but there is an unlimited number of ways, all apparently equally valid, in which you could decompose this total count into a sum of Poisson random variables.
Comment: Sum of Possions is Poisson. So, no, you can't decompose the sum... Unless the rates change in time in different ways, and you know something about this
Comment: Do you only observe their sum?
Comment: Yes, you can only observe the sum. But events never overlaps
Answer: Say, you observe $y_t$, where $y_t=x_t+z_t$, where $x_t\sim Poisson(\lambda^x_t)$ and $z_t\sim Poisson(\lambda^z_t)$. This means that $$y_t\sim Poisson(\lambda^y_t),$$
where $\lambda^y_t=\lambda^x_t+\lambda^z_t$
Let's say you can get $\hat\lambda^y_t$, how would you extract then $\hat\lambda^x_t,\hat\lambda^z_t$? There's no way unless you know something about the processes for $\lambda^x_t,\lambda^z_t$.

Decomposing multiple poisson process


Using InfluxDB with interpolate.linear does not output missing values

Question: I have some monthly counter measurements stored inside an InfluxDB instance, e.g. data like this (in line protocol):
readings,location=xyz,medium=Electricity,meter=mainMeter energy=13660 1625322660000000000
readings,location=xyz,medium=Electricity,meter=mainMeter energy=13810 1627839610000000000

These are monthly readings, not sharp to the beginning of a month (one is at 3rd of July, the other on 1st of August).
My goal it to interpolate these readings on a daily basis, so I stumbled upon the not so well documented interpolate.linear function from Flux (https://docs.influxdata.com/influxdb/v2.0/reference/flux/stdlib/interpolate/linear/).
But the only output I can generate with my function returns me the two given data values from my input.
import "interpolate"
from(bucket: "ManualInput")
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> filter(fn: (r) => r["_measurement"] == "readings")
  |> filter(fn: (r) => r["_field"] == "energy")
  |> interpolate.linear(every: 1d)

Am I missing something here? I've expected to have a linear interpolated value on each day... or is this not possible with Flux? (I'm using V 2.0.7)
Answer: I propose to add a yield() function.


What is an efficient way to remove loose vertices?

Question: I have a mesh that has some vertices between edges that do not need to be there. How can I easily remove these vertices without selecting them manually? I tired using limited dissolve but that get rid of anything that coplanar not just the floating vertices.
Comment: Think about it from an algorithmic perspective: how should Blender know which vertices "do not need to be there?" The only vertices that don't contribute to the geometry (besides vertices not connected to any edges) are indeed coplanar, so Limited Dissolve is probably the closest you'll get. In terms of actually achieving this particular result: as this looks like a circle, you could use circle select `C` in edit mode to select all the vertices in that ring, then deselect all the ones in a slightly smaller ring to be left with only those selected.
Comment: This isn't an answer to your question, but it is related. `Ctrl`+`Alt`+`Shift`+`M` selects *Non-manifold* geometry.
Answer: In some instances, depending on topology, the following can work:

Select one of the vertices that you want to remove.

Choose Select> Similar> Amount of Connecting Edges from the 3D view header.

Deselect any vertices that have been selected but that you don't want to delete (in this case, the corners) and choose Mesh> Delete> Dissolve Vertices to delete the unwanted vertices.
Comment: PS: manifolds can ignore the 3rd step.
Answer: The most efficient I guess would be to try and avoid them if you are trying to remove edge loops use delete Edge Loop you will avoid this problem as it deletes Edges and Vertices.
Note it isn't perfect and may create extraneous edges but select them and repeat the process usual only needed once.
Answer: Although you didn't specify how you came to have those loose vertices, it is common to get that situation when using 'dissolve edges' to remove edges from your geometry without leaving holes. When you use 'dissolve edges', the vertices that were part of the edges will not be deleted with the edges, however, they will remain selected. You can then just press delete and select 'dissolve vertices' to get rid of them too.
Comment: if you select a lot of vertices on an object that has a lot of faces, then the vertices will collapse and you will almost certainly be left with a very deformed object if you follow this method -- but, if you can get select the vertices (which is the difficult part), then you can absolutely use dissolve vertices. It's just that when you have thousands or millons of points, sometimes it's difficult to select the vertices that you want to dissolve.


Display public keys + fingerprints of Dropbear SSH server

Question: While I normally use OpenSSH I have Dropbear installed on a Debian system to provide a small SSH server for unlocking disk encryption during initramfs boot phase.
Dropbear and OpenSSH have different formats key files. I also don't want them to share the key pair and not convert Dropbear's key pair to OpenSSH.
How to just display Dropbear's public key in the OpenSSH format and/or its fingerprint?
Answer: Dropbear uses a binary format for storing the key and has no second file for storing the public key, especially not in a human-readable form.
The program dropbearkey is responsible for key generation but will also display the public key for the binary key file. The -y switch is important for reading the file, not writing it!
$ sudo dropbearkey -y -f /etc/dropbear/dropbear_ecdsa_host_key
Public key portion is:
ecdsa-sha2-nistp521 AAAAE2VjZHNhLXNoYTItbmlzdHA1MjEAAAAIbmlzdHA1MjEAAACFBAFygHJYm8rXlIrktbgGEcrfkipydP7ZM+mkWwot7lhnrYYuKvwMNE99YyvrKYT8fXnVaemSgOsigJDGAgdfCyJNjgDdNE4AU4RQRY4IN4PinnlMsw2Lv1BY1q+F2IcBBoSb/2OVTc2c5/LRQ7/rbPcqBpU8V3v67CTTULYY7yH1BTfnXQ== root@hostname
Fingerprint: md5 7d:c5:7e:43:a2:07:c3:93:a7:fe:5c:76:60:2e:a0:4c


Does Racquetball have a stand your ground rule?

Question: A friend just explained the 'stand your ground' rule in handball where, on hitting the ball, you are allowed to stand where you are and have no obligation to get out of the way of your opponent.  He said it was the same in racquetball but I'm pretty sure you actually are obligated to get out of the way if needed.  The official rules seemed to support my understanding but it's not clear enough.  Which is correct?
Comment: What version of handball is that?  Hinder rules vary, and official rules describe situations where you must get out of the way, similar to how it is in racquetball.
Answer: Rule 3.15 of the International Racquetball Federation states that "avoidable hinders", which result in loss of the rally, include:

(a) Failure to move. A player does not move sufficiently to allow an
  opponent a shot straight to the front wall as well as a cross-court
  shot [...]

This suggests to my mind that you must move out of the way of your opponent if it is necessary to do so to allow them to play their shot.


What kind of ecclesiastical structure did Ignatius of Antioch discuss in his epistles?

Question: There are approximately seven "genuine" epistles attributed to Ignatius of Antioch. I'm curious to know what kind of ecclesiastical structure he mentions in his epistles. If he discussed it, in what ways was it similar to and different from the ecclesiastical structure of today's Roman Catholic Church?
Comment: I recommend reading "From Apostles to Bishops" by Francis A. Sullivan.  It examines not only Ignatius of Antioch's views, but of most of the available 1st to 3rd century historians' and religious leaders' writings on the question of ecclesiastical structure.
Comment: Good question with a good answer. But I think it's worth noting that Ignatius' letters are not too long, and all [available online](http://newadvent.org/fathers/).
Answer: Francis A. Sullivan S.J devotes some 23 pages (pages 103-125) in From Apostles to Bishops to the letters of Ignatius.  Five of the seven letter credited to Ignatius were written to churches in the Roman province of Asia, and each of these communities had a bishop. On page 105, Sullivan says that the Letter to Polycarp, bishop of Smyrna, was the only letter that Ignatius actually addressed to a bishop. This is clear evidence that by the time of Ignatius (ca. 115 CE), bishops were being appointed in at least some cities in the eastern Mediterranean. There is a clear hierarchy in these letters, with deacons subject to presbyters and to the bishop, presbyters subject to the bishop, and the bishop receiving his authority from the Father, the "Bishop of all" (page 109).
Francis A. Sullivan S.J says, in page 107, that in Ephesians 3.2, Ignatius refers to "bishops appointed throughout the world," but says that most scholars now doubt whether in the time of Ignatius, bishops like him had been appointed "throughout the world."
Ignatius makes no mention of a bishop or presbyters in his Letter to the Romans, with his appeal directed to the whole community. On page 111, Sullivan says we can draw no conclusions from the absence of any mention of a bishop of Rome in this letter, although Sullivan elsewhere discusses the broader evidence that bishops had not yet been appointed in Rome. Ignatius was himself a bishop, as he refers to himself as the "bishop of Syria" in the Letter to the Romans. It is unclear from this whether other cities in Syria had yet begun to appoint their own bishops.
To provide context for the church hierarchy of which Ignatius was writing, Sullivan says (page 14) that a bishop is a residential pastor who presides in a stable manner over the church in a city and its environs. He says there is no evidence, nor is it at all likely, that any one of the apostles ever took up permanent residence in a particular church as its bishop. Sullivan goes on to say (page 15) the letters of Ignatius are the first Christian documents that witness to the presence of a bishop who is clearly distinct from the presbyterate, but this evidence is certain only for Antioch and several churches of western Asia Minor.
In the salutation of the Letter to the Romans, Ignatius refers to the Roman church "presides in the place of the district of the Romans ... and presiding over love." Sullivan says older Catholic scholars have seen here a recognition of the primacy of the church of Rome over the church throughout the Roman world, but says the word translated
"district" (chorion) means a limited area such as a city or town.


Why are augmented 2nds not used in 4-part harmony?

Question:
Here is just one example, but all throughout my textbook they seem to be saying that it is bad voice leading using aug 2nds. However, I tried to play a lot of the examples and they sound ok on piano. Is this a crazy outdated rule?
Answer: The rule comes from an older musical aesthetic in which augmented intervals sounded very strange to the ear. Also, they were considered difficult for singers to sing, and thus forbidden (or, at least, highly discouraged).
Aesthetics have changed, and so has the training and experience of singers. In a voice-leading exercise, an augmented second would be considered wrong, but in real-world music, it wouldn't be a big deal.
Comment: I might be better off asking a new question but here goes: why are augmented 2nds harder to sing if they are enharmonic to a m3? in voice leading, the m3 is a small very common leap.
Comment: It's more that augmented 2nds are more difficult to read than they are to sing, IMO. However, there may be tendencies to slightly mis-tune each note in a sung augmented 2nd (along the lines of sharpening sung leading tones).
Comment: @armani Although a2 and m3 are enharmonically equivalent, they sound very different in context, which is why the naming and spelling differentiations are important. You and I might find a2's easy to sing, but a few hundred years ago they were considered strange and difficult. In fact, augmented intervals in general were just "defined" as hard to sing.
Comment: ok and these aug 2nds are a result of the raised 7 in harmonic minor only right?
Comment: @armani That's certainly the most common source, but one should allow they might arise in some other situation as well.
Answer: In particular (as mentioned by Aaron), the problem is primarily with vocal music in a contrapuntal setting. There was little problem in using augmented seconds in instrumental music. Augmented intervals generally expand and chromatically sharpened intervals tend to move upward (like a temporary leading tone).
Augmented seconds are fine in arpeggiations of a dominant ninth (D-F-G-Ab-B in C minor for example.) I'm not sure about the example as the last two chords are an F#-b with a rising F#-G-A#-B soprano line. The trouble (to me) is that the VI -> V chord has  "covered" or "hidden" or "direct" parallel octave movement (GG to F#F#). In addition, there are parallel fifths (GD to F#C#). While these parallels are created with different pairs of voices, the involvement of the bass does make them stand out. The VI-V (parallel chords in root position are often difficult to connect nicely.


What is copula transformation

Question: I have seen that copula transformation changes my sample space to the range of $[0 \; 1]^d$ where d is the number of dimensions. Can anyone explain me about copula transformation?
Answer: I believe you're just referring to transforming each marginal distribution to $U[0,1]$ via the probability integral transform, which when applied to each of the variables individually, transforms a d-dimensional distribution to its copula.
For example, if you had a bivariate normal $(X,Y)$, and transform $U=F_X(X)$ and $V=F_Y(Y)$, then $(U,V)$ is a Gaussian copula.
e.g. see here
There are some recommended introductory readings here
Answer: Sklar's theorem says that (bivariate case), for any given joint distribution function $H$, of two random variables $X$ and $Y$, with uniform univariate margins, $F_x(x)$ and $G_y(y)$, of $X$ and $Y$ respectively, then there exist a copula function $C$, such that:
$$H(x,y)= C(F_x(x),G_y(y)) $$
If all margins is continuous the copula is unique.
The idea of copula transformation is that: Copula models allow to model the margins separately from the dependence structure. Hence, we transform all the variable to be uniform in order to capture the pure dependence structures between variables without any affect of the margins.
$u=F(x)$ and hence, $F^{-1}(u)=x$. So we can go back easily to the original data.

What is copula transformation


Numerically stable hyperbolic tangent

Question: The hyperbolic tangent is commonly used as an activation function:
$$
tanh(x) = \frac{e^x - e^{-x}}{e^x + e^{-x}}
$$
Although, it is unclear how this function is implemented to be numerically stable in frameworks like pytorch or numpy. Since $e^x$ will explode for any $x \gtrapprox 1000$, is the function being approximated in some way? Or are there static checks for big input numbers?
Answer: Commonly you divide the domain up into different accuracy,stability regimes and apply a different approximation within each.
For $|x|<1$ you can use a polynomial approximation, like Chebyshev. For $1<|x|\leq E$, $E$ depending on implementation of the formula, you can use a related formula to the one you described.
For $|x|>E$ you can use $\tanh(x) \approx sign(x).$
More details here from a documented implementation.
Comment: Thanks, using 64-bit floats I expect $E$ to be equal to the natural logarithm of the max value representation of a 64-bit float? ```np.log(np.finfo(np.float64).max)```

Numerically stable hyperbolic tangent


Research papers/articles comprehension

Question: I am new in the PhD field (hydroinformatics). I have a question: How can I understand a research paper thoroughly? I am perplexed about how the authors got the results. How can they calculate it? How did they get their graphs, tables, etc.? In general, I can understand the abstract and conclusion, but the methodology and discussion part of a research paper are quite a pain.
Comment: You are a new PhD and don't know very much. It gets easier with reading more papers, doing your own research, and writing your own papers.
Comment: Even after you've earned your PhD and can quickly read a paper in your field once through and understand it entirely if you start reading papers from another field you run into this problem again. Though the closer the new field is to the old, the less prominent this will be.
Comment: Do you talk about one specific paper or any paper?
Comment: @Sursula Thank you for your anwer, I am talking about any paper related to hydroinformatics.
Comment: @JonCusterThank you for your answer, That's a relief
Answer: Understanding comes with practice, experience, and discussion. Good abstracts and conclusions are written to be easily digestible, and in my experience a good number of academics primarily skim those two sections to see if a paper is "worth it" before diving into the methodology and discussion. That's because understanding those sections can take some serious effort, even for people who are well versed in the field! So don't lose heart if those are the scary sections.
To get there, you have to do a lot of work, read a lot of papers, and talk about those papers with lots of people. A PhD is very much not a solo effort. Do you have an advisor, labmates, or other professors in your department/field/organization? Ask them (particularly your advisor) about what their favorite papers are in the field, or if there are any good review articles recently. Then read those papers, take notes, and follow up by having discussions with other academics. "I read that paper you suggested, but I didn't quite follow their method of doing X. Do you have some time to talk about it?" They probably have insight that you're still developing and are often able to guide you in the direction of the right answer.
Answer: One of the best ways to learn about papers is to join a journal club which senior academics attend. They will know about all the little hidden things in papers 'They wrote that they did X, but we all know that really means they did Y'. They will be able to parse the complicated methodology that confuses you. Take notes, annotate the papers and keep them for later reference.
If there isn't a journal club, start one! Try and invite some senior academics to join - even post docs can be very helpful in learning about how to read and evaluate papers. The senior academics might be busy, but you'd be surprised at how much they enjoy talking and giving their opinion about papers once they get the chance...
I can't stress how much joining them has helped me critially analayse the literature and learn how to better design experiments and analyses. There's a whole trove of useful information hidden away in the minds of senior academics and one of the best things you can do as a student is to try and tap into it.

Research papers/articles comprehension


Sample size estimation, stumped

Question: I'm looking at patients that have attended a pain clinic for assessment and treatment program. I want to look for differences between the population that complete the program and the non-completers.
I want to compare completers vs non-completers on a number of variables, e.g. age, sex, employment status, number of medications, +/- mental health diagnosis etc.
Can anyone help me with a sample size calculation. I have been reading up trying to figure out an answer for hours and i honestly feel more confused now than before i started.
Comment: Do you mean you are trying to determine a proper sample size so the results have enough statistical power?
Comment: What are you trying to sample size here; whether there's a difference in proportion of subjects that complete vs. those who don't (one comparison) or if those two populations differ in these several variables (many comparisons which will likely have a different adequate sample size each)?
Answer: This is an age old dilemma. It's all up to the way you want to pose the problem. First, do you have a fixed maximal model in mind based upon good science or are you hypothesis generating? I'm guessing that because you want to do a sample size calculation then it's the former and your desire to cast it as a well designed study. Are you powering for all coefficients or is there a main variable or two? Let's first assume that you desire power for the coefficient of a single variable adjusted for potential co-founders (the rest). Then you'll want to consult
Self and Mauritsen, BIOMETRIcs 44, 79-86
"Power/Sample Size Calculations for Generalized Linear Models".
If you want power for more than a single variable's coefficient then you have to decide how many. Say two of the p variables. A simple approach is to use the conjunctive power e.g.
p( both variables are significant | both nulls are false )
~ p( a single variable is significant | its null is false)^2
So for 80% power just do the single variation calculation at 0.8^0.5 ~ 0.9 power.  This of course assumes independence which is conservative if there is positive correlation. It's probably good enough even if not. Want to be sure, do simultaneous under some kind of dependence model.
Good luck and happy reading.

Sample size estimation, stumped


Will USMT 4.0 in MDT 2010 Move/Migrate the .NK2 File for Outlook?

Question: We're about to begin a refresh project for about 100 XP Pro laptops and have a concern with regards to the .NK2 file which holds cached email addresses(?).  If possible we'd like to have USMT move/migrate this but I can't find anything that confirms that this happens automatically or has been done before.  I see lots of manual processes but at this point I'm not sure that we can use that.  Has anyone done this or seen this done?  Perhaps you can point me to a resource that can give me an idea how its done?  Any information would be appreciated.  USMT seems to get a lot of the details but missing this part seems odd.  Thanks in advance for any responses.
Comment: Are you also going to Office 2010 and Exchange 2010? Exchange 2010 now provides a server side cache for auto-completion of e-mail addresses. In previous versions such as exchange 2003 and exchange 2007 auto-complete data was stored locally in the outlook profile on the local PC in an NK2 file.

Because this auto complete data is stored on the server, it is available to the user regardless which PC they are using.
Comment: We're moving to Office 2010 but Exchange 2010 is on the near horizon.
Answer: I did some research and found out that you have to specify the Outlook and Office things in a custom.xml file while migrating.Custom XML examples
I then found a tool where you can generate such a file which also includes NK2 files. The tool is called USMT XML Builder.
You can generate with this tool the XML file needed for Office 2003 and Office 2007,which also includes NK2 files (and also a lot more needed for Office)
Answer: This can also be done from 2007/2010 to 2013/2016. In order for the nk2 files to import properly they need to have the same outlook profile name. Such as Default Outlook Profile to Outlook. Here is the Syntax you can place in your Custom.XML file.
<code><!-- Outlook Rename NK2 -->
    <component type="Application" context="User">
    <displayName _locID="custom.Outlook">NK2 filename</displayName>
    <role role="Data">
     <detection name="Office 2007">
    <conditions>
      <condition>MigXmlHelper.DoesObjectExist("File","%CSIDL_PROGRAM_FILESX86%\Microsoft Office\Office12\outlook.exe")</condition>
    </conditions>
  </detection>
    <rules context="User">
      <include>
      <objectSet>
        <pattern type="File">%CSIDL_APPDATA%\Microsoft\Outlook\ [Default Outlook Profile.NK2]</pattern>
      </objectSet>
      </include>
      <locationModify script="MigXmlHelper.RelativeMove('%CSIDL_APPDATA%\Microsoft\Outlook\ [Default Outlook Profile.NK2]','%CSIDL_APPDATA%\Microsoft\Outlook\ [Outlook.NK2]')">
        <objectSet>
          <pattern type="File">%CSIDL_APPDATA%\Microsoft\Outlook\ [Default Outlook Profile.NK2]</pattern>
        </objectSet>
      </locationModify>
    </rules>
 </role>
</component>
</code>
Modify the Default Outlook Profile.Nk2 to Default profile name you have in your organization. Then change it to what you want the profile name to be (here I use Outlook.Nk2).


At end of Not Fade Away (2012), is that Sunset Boulevard?

Question: The end of writer-director David Chase's film Not Fade Away has the character Evelyn (Meg Guzulescu) dancing on an L.A.-area boulevard.  I assume this is Sunset Boulevard, can anyone confirm?  (It's a haunting moment, where Evelyn dances in the middle of a deserted, midnight street.)
Comment: Can you find a screenshot of it?
Answer: If you are referring to this (youtube.com/watch?v=LBO5pLMPmDE) scene:
Yes, it shows Sunset, but not in front of the Cinerama Dome which is located at 6360 Sunset Blvd.
Meg is dancing west of Sunset and N Cahuenga.
The Dome in the movie (as CGI/build set) is located a block to the west at 6450 Sunset Blvd (Staples).
It can be easily recognized via the building right before the theater, to the left shown at 0:42 in the link above, which is 6430 Sunset Blvd (CNN).
Comment: Perhaps was easier to get permit for that next block.  In any case, thanks for the detailed confirmation!


Type annotations can only be used in TypeScript files

Question: I have created a new react-native project using:

npx react-native init

But on App.js there is an error here:
const App: () => React$Node = () => {
  return (
...
)}

There is a red underline in "() => React$Node"
And the error is:

Type annotations can only be used in TypeScript files

I know that this can be fixed by just using "const App = () => { ", but I remember that I have created some other projects before that would not have this error when created. I noticed that this started to happen only after I created a project with template typescript. Now every project I create start like this, and I don't think this is the only thing on the code that is different, because I'm finding a lot of odd errors that wouldn't happen before. The project now will only render right if I use typescript, even if I change this line.
My question is: How can I go back to when the project would not require typescript to work??
Answer: The problem is that your file name is App.js.  You need to change is to App.tsx.


Compute monthly realized variance for Fama-French factor

Question: I need to compute monthly realized variance from daily data for Fama-French factors. Knowing that Fama-French factors is the difference of return between different type of stocks, for example SMB factor is the difference between returns on portfolios of small stocks and portfolios of big stocks, should I again take the sum of squared return from those factors to compute realized variance? I mean take the return from the data that is already return to compute monthly realized variance? Or is it better to follow the formula in Moreira, A., & Muir, T. (2017) (pictured below) to compute the monthly realized variance?
Answer: Fama-French factors are already returns so you should not calculate the returns on the Fama-French factors but simply calculate the variance in the normal way (by squaring the difference of each datapoint from the mean and summing).
Recall that the core of the Fama-French model is the equation
$$
r=r_f+\beta_1(r_m-r_f)+\beta_2(SMB)+\beta_3(HML)+\epsilon
$$
See the CFI website for definitions of terms and more details.
Since each $\beta$ is a dimensionless number, the quantities $r_m-r_f$, $SMB$ and $HML$ are in the same units as $r$. This supports the idea that, as you correctly point out, Fama-French factors are returns.
Therefore, if you wish to compute some statistic (e.g., variance) of $SMB$ you can proceed as if you were computing that statistic for returns.


How can we describe a group of things as having just the right number, i.e., not too many, not too few?

Question: I'd like to use a single word or an idiomatic expression to express that the school's breaks are well-spaced and not too many. Is there an adjective that mean just the appropriate number?
Comment: I'm sure someone can think of one, but I can't at the moment. Any of the ways you've already described it would be fine.
Comment: A good starting point for answering these questions is to begin with the word in your language, and use a bilingual dictionary to give suggestions of possible words.  If no such word exists in your language then you might be lucky, there might be a word in English, but probably not. Would a phrase like "ideal number of" work for you?
Answer: You could use optimum/optimal

best; most likely to bring success or advantage; best; the best or most effective possible in a particular situation (Cambridge)

As in this medical article:

Is there an optimum number of night shifts?

You could say that the school's breaks have optimal frequency or distribution.
Answer: Many options:

There are the ...

perfect
ideal
appropriate
right
correct
optimal

... number of breaks

You need to describe the number not the breaks. So I don't think that there is an expression The breaks are .


How to find the next free slot for an appointment with Outlook for Mac 16?

Question: In other versions of Outlook the room finder also suggests free time slots. Apart from the fact that it's a teams meeting and I don't need a room, even if I add a room, the room finder doesn't suggest a free time.
Answer: What other versions of outlook do you mention?
Based on my research on Outlook for mac(version is as shown in the below figure), the suggested time can't be found too, which is the same issue with yours. I'm afraid that it's by design.

However, it's suggested that you could check the free/busy information shown in the scheduling grid. For more information about room finder, please refer to: Room Finder opens in the scheduling page of your meeting invitation.


what is a "proxy based" framework?

Question: I just started reading about spring , and a book mentioned "Spring AOP is a Proxy based framework" . What is meant by "Proxy based" framework.
Comment: It's a reference to a [proxy design pattern](http://en.wikipedia.org/wiki/Proxy_pattern).
Answer: The framework is using the java.lang.reflect.Proxy to do the work
In general Aspect Oriented Programming (AOP) in Java is implemented by means of instrumenting the target objects in some manner. There are many ways to do this but a common approach is to use the Proxy class.
This provides a facility to create a new object at runtime based on a given interface. You can then adjust the behaviour of the proxy to include extra features, such as logging or security boilerplate code, before handing control over to the original object.
An alternative approach, is to use subclassing. The proxy extends the original class and weaves the aspect before handing back to the super class. This fails if your class has final methods that need proxying.
You can read more about it in the Java reference here: http://download.oracle.com/javase/6/docs/api/java/lang/reflect/Proxy.html
Alternatively, take a look at Spring in Action (pp 124).
Answer: As Gary Rowe says: some implementations of Aspect Oriented Programming generally rely on the imposition of a layer between the object and the rest of the system.  This layer is usually called a proxy or a dynamic proxy.
From the Castle Project site:

Proxy objects can assist in building a flexible application architecture because it allows
  functionality to be transparently added to code without modifying it. For example, a class could be proxied to add logging
  or security checking without making the code aware this
  functionality has been added.

what is a "proxy based" framework?


Advice on laptop battery life

Question: I am planning to buy a laptop and, as I have never had a laptop of my own before, I have started to read up on the best way to charge a laptop so as not to damage battery life.
Is it all right to charge it to 100%, unplug the charger, let the battery drain to something like 30% and then repeat? Furthermore, does using the laptop while the charger is plugged in harm the battery? I believe that it doesn't, but I just want to make sure that this is the case.
EDIT: I am referring to Lithium-ion batteries.
Comment: It's impossible to answer this question. It depends on the battery technology and the charging system. Neither of which we have any information about. You should be able to assume that the manufacturer knows better than you and you should just leave it plugged in and charging unless you need to run it on battery. What is true is that you can only charge and discharge a battery so many times, so that act alone shortens the battery life.
Comment: I added the fact that I was referring to Lithium-ion batteries. @neverMind9 thank you.
Comment: Possible duplicate of [Should laptops remain plugged in when their battery is 100% charged?](https://superuser.com/questions/12838/should-laptops-remain-plugged-in-when-their-battery-is-100-charged)
Comment: Related: [Is it better to use a laptop on battery or on AC power?](https://superuser.com/q/12358/194694)
Comment: According to [BatteryUniversity](https://batteryuniversity.com/learn/article/charging_lithium_ion_batteries), Lithium-ion batteries prefer not to be charged in deep cycles. But if the battery is easily replaceable, and you need the entire capacity, feel free to use it.
Answer: You need to know that:

Rechargeable Lithium-Ion batteries have a limited life and will gradually lose
their capacity to hold a charge, and this is irreversible.
Lithium-Ion batteries continue to slowly discharge (self-discharge) even when
not in use or while in storage.
Avoid completely discharging batteries.
Lithium-ion batteries don't like being charged all the way up and run all the
way down. Better to do little recharging here and there.
Experts advise that after 30 charges, you should allow lithium-ion batteries
to almost completely discharge once, but never totally.
(But I don't think that most people bother with it.)
You can leave your laptop plugged in all the time, and you cannot
overcharge it. Most laptops are smart enough to cut the battery out of
charging once it's full.
Comment: According to the usual advice, you may leave it connected. However, for long periods it might be safer to disconnect to avoid power surges. For very long periods, the battery might self-discharge, and it's said that if it becomes too low it might suffer or even die.
Comment: So even when the battery is at 100% I can still leave it plugged in and cause no harm?Would this be better than unplugging it and recharching it later?
Comment: @harrymc The charging circuit does handle selfdischarge and I never had a power surge in my entire life.
Answer: @Harrymc answer is largely correct, but there are additional things you may wish to consider -

Lithium batteries age even when not in use - how much depends on temperature and how full it is.
Some laptops will allow you to set a maximum charge percentage (in BIOS). A maximum charge of less then  say 75% will greatly prolong the life of your battery. You should use this if your laptop is normally left plugged in.
Using the charger while battery is plugged in wont typically damage the battery and can prolong the systems life by preventing it from discharging and needing to be recharged.  Be aware of CHARGING the battery while using the laptop. This will work fine but can generate more heat - and heat is not ideal for a lithium battery.

Advice on laptop battery life


What is the purpose of bonus points in Gin Rummy?

Question: What purpose do the bonus points after a player wins a game of Gin Serve?
Let's say two players agree to play a game to 100 points. At the end of the game, the typical rules call for bonus points to be awarded: 25 points for each winning hand, 100 points to the winner, double points for a shutout...  Why?
If I was the player that reached 100 first, what good are even more points?
I'm assuming that this is a method for placing wagers on the game?
And how (if at all) do bonus points factor into games where the players agree to a "best of five games (e.g.) arrangement?
Answer: The most common way of betting money on Gin Rummy (according to this site) is to choose a rate per point (say $1) that the loser pays the winner - e.g. if you lose 70 to 220, you pay $150. When you're playing for money, there's probably an approximate stake you want to play for - smaller stakes will feel trivial (who wants to win one penny?) but larger stakes could be devastating if you lose. Without bonus points, a win could be anywhere from 1 point to ~150, and there may be no per-point rate which is non-trivial when multiplied by 1 yet non-devastating multiplied by 150. Bonus points - say 100 for winning - are a simple way to decrease this variance, since now spreads will be between 101 and ~250, so the worst possible loss is only ~2.5 times as bad (or good, for the other guy) as the closest possible spread.
As far as I can tell, best-of-5 matches tend to be played in settings where bonus points are not relevant, e.g. tournaments where all that matters is who wins the match.
Comment: The key idea is that what matters is the *ratio* between the biggest possible win and the smallest possible win. So if the win bonus were a *thousand* points, that would decrease the *variance* because you could play for a penny a point and find yourself paying almost exactly $10 for every loss. Whereas without any bonuses if you wanted to be playing for approximately $10, you'd have to set it at say 50 cents per point instead, and then sometimes you'd find yourself paying just 50 cents and sometimes shelling out $50, depending on the final spread.
Comment: Won't 100 for winning make the spread worse?  The winner is already ahead (definition of winning); now they get 100 for winning, 25 for each hand won, double for shutout, etc. -- all these things put the winner still further ahead.  IOW, you've got the bonus points backward.  Shutout -- you get 100 for the win, 25 for each hand played (since you won them all), and double for shutout, that looks like 500-600 points from a 100 point game.
Comment: Now I see what you're doing -- might want to include that level of information in the answer.


Neural Network not Deep

Question: I have found this image link I would like to know what NNs are not deep neural? The first three?
Also what kind of functional activations do they use?
Answer: The term 'deep' in deep learning is not well defined, but is generally meant to apply to networks that have stacked multiple layers on top of each other to create a deep network. It is therefore up for debate when a network is considered deep or not, but you could use the definition that a deep network has two or more hidden layers. From your overview, examples of non-deep networks would therefore be the perceptron and simple feed forward network. The activations used in the network have no relation to whether a model is deep or not as it only relates to the number of layers in the network.
Comment: Thanks! What about Auto Encoder (AE), Variational AE (VAE), Denoising AE (DAE), Sparse AE (SAE) and Deep Feed Forward (DFF)? Can I consider them as Neural Network or Deep Learning?
Comment: Based on the architectures shown and the definition of a deep network above the four auto encoder architectures would not be deep whereas the deep feed forward network would be. However, keep in mind that the architectures shown are a general overview of what for example an auto encoder looks like, however there are also auto encoders with more layer which would be considered deep.
Answer: The single layer neural network - the Perceptron - was first implemented by Frank Rosenblatt in 1957 using hardware (!!) - that is: resistors, electrical motor, and a potentiometer! The perceptron had one layer of neurons, (not including the output layer), and it could tell the difference between simple shapes and letters.
According to Google's N-Gram Viewer it was a long time before the term 'Deep Neural Network' was used in a book (~1980), and much longer (~ late 2000's) before it gained popular usage:

So to answer the question, I suspect although it's somewhat subjective, I think the Perceptron is the only true single-layer neural network in your diagram, and therefore the others would be considered 'deep'. Some may consider other 'shallow' neural networks (like 'feed forward netural nets') to not be deep, but it's worth noting that although shallow in structure, the term 'feed forward netual network' didn't come into popular parlance until slightly after the term 'deep neural network' (see here).
Answer: Alexnet was a revolution in image recognition in 2012 (https://proceedings.neurips.cc/paper/2012/file/c399862d3b9d6b76c8436e924a68c45b-Paper.pdf) and the paper was titled "Deep convolutional neural networks".  Referring to neutral networks as "deep" was unusual at that time.
They used 8 layers, and hugely increased the state of the art (SOTA).
I conclude from that, that at least in 2012, 8 layers was considered deep.
Since then, I'd argue that 8 layers is no longer considered deep, but pretty standard for many image processing tasks.
I'd therefore argue that the definition of deep has changed and increased over time, and we've become better at training ever-deeper networks.
Comment: Are you relying solely on this article? Or have you found other information that says Deep Learning has more than 8 layers?
Answer: One of the reasons deep neural networks have taken off is because GPU hardware has improved. The computations needed for practical deep networks are often highly parallelizable. Thus, I think one indicator of "deep" in addition to the standard criteria of ">= 2 layers" is that the network is structured so that many computations can be done in parallel.
Conversely, practical networks which are not highly parallelizable are often not "deep".
Comment: I think this is exactly the wrong way around. The standard parallelization in neural networks is wide, not deep.
Comment: @MSalters What I mean is: the per-layer computations are massively parallel in both the forward and backward directions, which enables one to stack layers deeply since the cost of an individual layer is greatly reduced.
Comment: That makes more sense, yes.
Comment: @MateenUlhaq It's not sufficient, however, unless you can also deal with the vanishing gradient problem.

Neural Network not Deep


Set background colour of cell to RGB value of data in cell

Question: I have a column containing RGB values, e.g.:
127,187,199
67,22,94

In Excel, is there any way I can use this to set the background colour of the cell?
Answer: You can use VBA - something like
Range("A1:A6").Interior.Color = RGB(127,187,199)

Just pass in the cell value.
Answer: Setting the Color property alone will guarantee an exact match. Excel 2003 can only handle 56 colors at once. The good news is that you can assign any rgb value at all to those 56 slots (which are called ColorIndexs). When you set a cell's color using the Color property this causes Excel to use the nearest "ColorIndex". Example: Setting a cell to RGB 10,20,50 (or 3281930) will actually cause it to be set to color index 56 which is 51,51,51 (or 3355443).
If you want to be assured you got an exact match, you need to change a ColorIndex to the RGB value you want and then change the Cell's ColorIndex to said value. However you should be aware that by changing the value of a color index you change the color of all cells already using that color within the workbook. To give an example, Red is ColorIndex 3. So any cell you made Red you actually made ColorIndex 3. And if you redefine ColorIndex 3 to be say, purple, then your cell will indeed be made purple, but all other red cells in the workbook will also be changed to purple.
There are several strategies to deal with this. One way is to choose an index not yet in use, or just one that you think will not be likely to be used. Another way is to change the RGB value of the nearest ColorIndex so your change will be subtle. The code I have posted below takes this approach. Taking advantage of the knowledge that the nearest ColorIndex is assigned, it assigns the RGB value directly to the cell (thereby yielding the nearest color) and then assigns the RGB value to that index.
Sub Example()
    Dim lngColor As Long
    lngColor = RGB(10, 20, 50)
    With Range("A1").Interior
        .Color = lngColor
        ActiveWorkbook.Colors(.ColorIndex) = lngColor
    End With
End Sub

Comment: Is there any way to get this to loop through all cells with data in column H?
Answer: Cells cannot be changed from within a VBA function used as a worksheet formula. Except via this workaround...
Put this function into a new module:
Function SetRGB(x As Range, R As Byte, G As Byte, B As Byte)
  On Error Resume Next
  x.Interior.Color = RGB(R, G, B)
  x.Font.Color = IIf(0.299 * R + 0.587 * G + 0.114 * B < 128, vbWhite, vbBlack)
End Function

Then use this formula in your sheet, for example in cell D2:
=HYPERLINK(SetRGB(D2;A2;B2;C2);"HOVER!")

Once you hover the mouse over the cell (try it!), the background color updates to the RGB taken from cells A2 to C2. The font color is a contrasting white or black.
Answer: Sub AddColor()
    For Each cell In Selection
        R = Round(cell.Value)
        G = Round(cell.Offset(0, 1).Value)
        B = Round(cell.Offset(0, 2).Value)
        Cells(cell.Row, 1).Resize(1, 4).Interior.Color = RGB(R, G, B)
    Next cell
End Sub

Assuming that there are 3 columns R, G and B (in this order). Select first column ie R. press alt+F11 and run the above code. We have to select the first column (containing R or red values) and run the code every time we change the values to reflect the changes.
I hope this simpler code helps !
Answer: To color each cell based on its current integer value, the following should work, if you have a recent version of Excel. (Older versions don't handle rgb as well)
Sub Colourise()
'
' Colourise Macro
'
' Colours all selected cells, based on their current integer rgb value
' For e.g. (it's a bit backward from what you might expect)
' 255 = #ff0000 = red
' 256*255 = #00ff00 = green
' 256*256*255 #0000ff = blue
' 255 + 256*256*255 #ff00ff = magenta
' and so on...
'
' Keyboard Shortcut: Ctrl+Shift+C (or whatever you want to set it to)
'
  For Each cell In Selection
    If WorksheetFunction.IsNumber(cell) Then
      cell.Interior.Color = cell.Value
    End If
  Next cell
End Sub

If instead of a number you have a string then you can split the string into three numbers and combine them using rgb().


How to determine a successful share by addthis service

Question: One of my client wants to get some logic done on server side immediately after a member successfully share a link from his site. The problem is that some time member just open the share dialog by clicking the button and close it without sharing.
I was trying to use add eventListener to event type "addthis.menu.share" but this event get fired as soon as dialog is opened by clicking the service icon. It never determine whether a user really shared the link or just close the opened service dialog without sharing.
SO my question is there any way to know if a user has successfully shared the link immediately after sharing?
Answer: Unfortunately, none of the services (FB, TW, G+, etc.) provide any type of callback/response that can be used to determine if the user actually shared the page.  This makes it impossible to know if the share actually occurred in realtime.  You can use either the APIs from the service like FB:
http://graph.facebook.com/http://www.addthis.com
To get the number of shares or you can use the Analytics API from AddThis:
http://support.addthis.com/customer/portal/articles/381264-addthis-analytics-api#.UJqEWeOe_L4
I hope this helps.
Comment: sharer.php and/or the share button aren't in the current documentation, only the like button / feed dialog / send dialog are, those all have a callback you can subscribe to with [FB.Event.subscribe](https://developers.facebook.com/docs/reference/javascript/FB.Event.subscribe/)
Comment: Well, Facebook's current APIs provide a callback when the content is shared, but i think addThis uses the old 'sharer.php' endpoint
Comment: Oh really, could you provide a link to the documentation for that?  I would be interested in seeing how it works.


How to introduce a foreign idea to readers

Question: I'm writing a book with a world similar to ours but at the same time is very different. I don't know how to do it smoothly without overloading the reader with information but at the same time giving them enough information so that everything makes sense.
Comment: A few more details would give us more to work with. Is this scenario the same world only with a different history (Fatherland) or a very similar world with a differing ecosystem and cultures? Perhaps it is a twinned world (upsidedown) where both are similar to our world only mirror images of each other.
Comment: It's kind of like vampires or werewolves. Like not everyone knows they exist. But the MC does.
Answer: Like with so many non-mainstream settings or ideas, just present it as normal.  Give a minimum of information but allow the reader to figure much of it out.
Many works use the troupe of using a naive character as a stand in for the reader.  While this sometimes works, it's also overdone and usually fairly tedious.  Only do this if there is a really good reason to have a naive character there.  And don't have other characters explain everything to her/him.
Sometimes just a few words is all it takes to explain a radically different setting.  For example, instead of a long infodump about the effects of having two moons, maybe have a couple kids laugh at the families at the beach who didn't plan on it being double-moon tide and getting all their stuff wet.
A wonderful example of how to do this is The Golden Compass.  That world is like Earth in many ways, down to the British college system.  And at first the book doesn't seem like fantasy.  Then the author matter of factly mentions "daemons." The word is puzzling but then the reader sees it means visible energy manifestations into animal shapes, something that every person has exactly one of.  Yep, not our world.  It goes on from there, getting more and more fantastical with every page.
Answer: This is a classic problem. It's especially true for fantasy and science fiction stories where basic facts about the history, culture, and science of this world are fictional and thus not familiar to the reader. But presumably this information is common knowledge to all the characters, so it would be out of place for them to tell each other. For one character in a fantasy story to tell another, "Ruritania is a large country on the continent of Freedonia" would be like a character in a story set in 21st century America telling a friend, "The United States is a large country on the continent of North America".
This problem isn't specific to fantasy and sci-fi; it can be true in any story. How does the reader know that Fred is a policeman or that Bob and Sally dated in high school? Etc.
Common solutions include:

Have characters lecture each other about what the character already knows but the reader doesn't. Have them begin by saying, "As you know ...", and then proceeding to explain what the person already knows and the speaker knows he knows.

This is pretty lame and writers are continually warned against doing it.

Include a character who does not know what everyone else knows.

Many fantasy and sci-fi stories include a character from 21st century America travelling to this time and place, so that he knows pretty much what the reader knows and anything else has be be explained. He has a rational reason to ask the same questions the reader would ask, etc.
Great if it works in your story, but often it doesn't.
Another popular idea is to have a scene where a teacher tells school-children about history or whatever information.
In my humble opinion, this sounds like a good idea but rarely works, because the school-room scene usually has to be rammed into a story where it is totally out of place. A character who is not a teacher suddenly shows up giving a "guest lecture" at a school for no apparent reason. Sure, sometimes it works. If you have Captain Kirk teaching a class on military tactics at Starfleet Academy where he describes how the last three wars with the Klingons went, yeah, I can believe that. But when you have Captain Kirk show up at an elementary school to give a lesson on Federation history, sorry, that strikes me as very implausible. Even if you come up with some justification -- his orphaned nephew asked him to play his dad for "parents tell kids about their jobs" day at school or something -- it will likely sound contrived.
I recall a movie, "Harrison Bergeron", that has a scene where a teacher is quizzing the class, and one student has all the answers while all the others sit silently. This allowed the movie to both tell us the sci fi history, and also tell us that this young person is such a genius that it is causing him social problems, at the same time. It was still a bit strained, I thought, but a good try.

Introduce small amounts of information in an off-hand, indirect way. Real people don't lecture each other about the other person already knows, but they might mention a fact that everyone present knows in order to make a point. Like I wouldn't expect Captain Kirk (okay, I've got Star Trek analogies in my head now), sitting on the bridge of the Enterprise, to announce to the crew, "I am captain of this ship, the Federation Star Ship Enterprise." Presumably they all know that. But it would not be silly for him to say in a conversation, "Since I became captain of the Enterprise, I have had to deal with a lot of problems worse than this revolt on Rigel 7." Now we know that the character is captain of the ship, the ship is called the Enterprise, and there is some sort of revolt happening on Rigel 7, without anyone having to lecture about these things.

I recall a movie about a computer crime (forget the title) where one of the criminals has a girlfriend who knows nothing about computers, so they periodically have to explain things to her.

Explain the information narration. Interrupt the action briefly to tell the reader what he needs to know. This is simple and straightforward and doesn't involve any strained dialog. Writers often avoid this because it can be boring and it breaks rules like "show don't tell". Personally I think writers avoid it too much. I much prefer a story where the narrator just tells us the necessary background information, rather than coming up with implausible reasons for characters to tell each other.
Answer: One of the best methods I've used to introduce a new idea in my fantasy writing is to use a character POV who is foreign to the concept and get introduced to it by someone who is well-versed in it. It would be too obvious to put that character into a lecture about it, and it would be boring. But, you can make those characters journey together for a bit, and the idea gets introduced in simple ways, bit by bit. The dissemination of the concept would feel natural if you create human interaction that feels natural. Don't give away too much but give enough to leave the reader with a taste for more.
A good example of this would be Gandalf's occurrences in Frodo's journey. You don't know a whole lot about his powers but enough to know he's very powerful.
Answer: Vampires and werewolves are such a staple of folklore that introducing the reader to the fact of their existence can be done in many ways.
In Interview with the Vampire a nervous journalist saw something he couldn't explain and learns about vampires from a world weary vampire.
Perhaps your MC collects the various items that are said to be weaknesses of vampires. His home might have many mirrors, garlic hangs from his door and festoons the kitchen. His picket fence looks remarkably like a series of stakes hidden in plain sight and he never invites people into his home.
You could mention the various things he collects and the reader will probably start wondering if there might be a vampire in the closet.
Perhaps a neighbor who watches too much television or reads gothic novels stops by and wonders if the man is preparing for vampires. He might even joke about it.
Drop hints about why your MC is in on the secret - was a loved one killed? Did he witness something that changed his life?
Moonlight did it well - a private investigator who works at night and has some odd quirks because he a vampire living among us.
In Forever Knight, the MC is a detective who is a vampire and his partner learns the truth - and that there is a hidden subculture of vampires in the city he thought he knew so well.
There are so many vampire/ werewolf tales out there that you can be rather subtle and build to the first time it is crystal clear that there are other species among us. Your reader will probably figure it out rather quickly.
Prey took that and gave it a twist - a new species of human that is stronger, faster and smarter than homo sapiens. The enemy was evolution.


Is there a place where I can see how all past game choices affect dragon age inquisition

Question: As the title says I was wondering if there is anywhere online where I would be able to see a list of all of the choices that you make across dragon age and dragon age 2 and see how it would affect dragon age inquisition?
Answer: The Dragon Age Keep allows you tailor what choices you did in the earlier Dragon Age: Origins and Dragon Age 2. This allows you to make a save that you can use in Dragon Age: Inquisition and see how one choice affects events later on.
Furthermore, quoting their website:

"Watch and make a few key choices in the Interactive Story Summary,
  then use the Tapestry to further customize choices from Dragon Age:
  Origins, Dragon Age II, and all DLCs, to create your first world
  state."

You can read more about this in this blog post and check it out for yourself at https://dragonagekeep.com/
However, this service is only provided to make your own story prior to Dragon Age: Inquisition. It does not tell the tale of what happens in Dragon Age: Inquisition, I guess that's up to the player.
Gamesradar has an article about what vital decisions impact the gameplay in several major ways in later Dragon Age games, here.
Comment: This doesn't answer the question how the decisions affect Dragon Age: Inquisition. Also the information found in the linked Gamesradar article is wrong.


how to change color of instances of a symbol

Question: I have symbol in flash cs5 library. and make some instances of it in stage. is it possible to change color of one instance without changing color of other instances?
I try to change color of one, but the color of other change too.
Comment: Not directly no, especially not in new illustrator CC which dont allow nested symbols. But look at this post for a way to [circumvent the problem](http://graphicdesign.stackexchange.com/questions/66105/illustrator-symbolic-linked-objects/66119#66119)
Answer: You can find the Adobe Flash Professional CS5 & CS5.5 Help as a PDF here. You should read through it, save it and use that for future reference.
From Working with symbol instances

Creating Instances
To specify color effects, assign actions, set the graphic display mode, or change the behavior of new instances, use the Property inspector. The behavior of the instance is the same as the symbol behavior, unless you specify otherwise. Any changes you make affect only the instance and not the symbol.

And

Editing Instance Properties
Each symbol instance has its own properties that are separate from the symbol. You can change the tint, transparency, and brightness of an instance; redefine how the instance behaves (for example, change a graphic to a movie clip); and specify how an animation plays inside a graphic instance. You can also skew, rotate, or scale an instance without affecting the symbol.

So no, you can't change the colors of a specific object. You can change the tint color property and/or add a color effect though.


convert 1:M to 1:1 relation salesforce

Question: I have a MD relation between two custom objects. So, the scenario is, right now I am able to create many child records (i.e. 1:M relation), but I have to restrict it to only one record creation (i.e. 1:1 relation) without changing the schema. Please help
Comment: you can create a before insert trigger on child object and check whether  child record is already available or not for same parent. if one record already available then throw the error message.
Answer: As you are already using a master detail relationship. So here is one easy solution for you.

Create one Roll up summary field and do count of child record and add
  validation that count should not be greater then 1.

You don't need any apex code for this and if in future you want to change the limit just update the validation rule and if needed can deactivate that.

convert 1:M to 1:1 relation salesforce


SSIS Script Component + Helper Assemblies (.dll's)

Question: I got a script component which does Transformation / DataType conversions / Creating some calculated columns.  All the transform validations / datatype conversion methods and for new column generation is put into custom .dll.
As this script component would be same for all other tables, only thing is to define input / ouput columns and apply validation methods on required columns.
This all works fine.  On production server where do I need to deploy my .dll.
Would just putting it into GAC will be enough or need to do something else.
Regards
Answer: You just need the DLL GAC'ed on the SQL box that runs the package.
Check out the SSIS deployment guide...
PK  :-)


What are the maximum columns in an Access 2003 query?

Question: What are the maximum allowed number of columns in a query in access 2003?
Answer: 255 I believe.  You can check by going to Help > Specifications > Query within Access.
Answer: As a general rule, if you ever find yourself asking a question about the maximum hardcoded limit of a technology, it's time to step back and verify that you're taking the right approach.  Perhaps a query against access that's pulling in hundreds or thousands of columns isn't the right approach.
Comment: I think it's a legitimate point to raise, particularly with applications like Access that don't scale very well.
Comment: Any table or query with number of columns approaching 255 is badly designed and that's the source of the problem, regardless of the database engine in use.
Comment: Sometimes you're forced to bring in data for conversions from other poorly designed systems in order to clean them up. Doesn't mean you are going to place it in production. If you do, it will either show up in poor performance or it just doesn't matter how many columns your table has.
Comment: That's a poor answer.  Perhaps I have data that I am querying which is really wide, or I need to tie a couple of tables together which are all wide.  Often in software you have to do things that may not be the right approach but gets to your end result.
Comment: Access is being used as a quick report generator, something it's really good at.
Answer: From Access Help File
Thank you Ben
Number of enforced relationships: 32 per table minus the number of indexes that are on the table for fields or combinations of fields that are not involved in relationships
Number of tables in a query: 32
Number of fields in a recordset: 255
Recordset size: 1 gigabyte
Sort limit: 255 characters in one or more fields
Number of levels of nested queries: 50
Number of characters in a cell in the query design grid: 1,024
Number of characters for a parameter in a parameter query: 255
Number of ANDs in a WHERE or HAVING clause: 99
Number of characters in an SQL statement: approximately 64,000
Answer: Maximum numnber of column that you can add in ms access query is 255 but Let me tell me one thing :
In access you can make query in two ways

Create query in design view
Create query by using wizard.

For the first option you will have only a max of 16 columns to add in a query
but using the second option you can add upto 255 columns in your query.
:)


Can BadUsb only be delivered via USB?

Question: BadUsb works by infecting a computer when plugged into the USB port.  Is it also possible for an attacker who gains control of a system, such as remote access, to then infect any connected USB devices?  Or does it only affect the ports it's plugged into?
Comment: At least for Phison based devices (around half of devices), as long as an attacker has Administrator/root privileges, they would be able to place the device in boot mode and update the firmware. Local or remote doesn't matter.
Answer: If a USB stick accepts unsigned firmware updates then yes it's vulnerable to a bad USB attack.  There are products out there that only accept digitally signed firmware updates.  These devices are not susceptible.
http://www.ironkey.com/en-US/solutions/protect-against-badusb.html
Comment: At least for Phison controllers (about half of devices), there's a boot image that loads the firmware from NAND and executes it; it's that boot image that should perform validation - it's likely this check isn't done to improve performance. The host PC has no idea what's executing on the drive - that's what makes this technique so effective.
Comment: If USB stick includes basic storage sticks, what firmware would it have and how are the stick autonomous enough to accept or reject firmware?
Comment: "As explained by the researchers, the best protection against this vulnerability is to use code signing for firmware updates. If the signed firmware is modified, the device cannot authenticate the firmware and simply will not operate. This prevents the infection from spreading but results in an unusable device. That is why in addition to using signed firmware, IronKey protects the mechanism used to update the firmware with hardware-based security keys. This prevents tampering with the signed firmware, which would leave the device unusable."
Comment: But is IronKey more autonomous than than normal flash eeprom? I would have thought for normal flash device that decisions on firmware validity are made by the host operating system.
Answer: Once an attacker gains control of a system he may use it to try and compromise vulnerable USB devices plugged into it in hopes of compromising the other systems to which the compromised USB devices will be connected.
And the attacker doesn't care about which ports are used, he'll just probe all of them in hopes of finding & compromising a vulnerable USB device.
Comment: marked this as correct because I feel it answers the question with more accuracy, but I appreciate both responses.

Can BadUsb only be delivered via USB?


Java Web Services - Is Axis Necessary?

Question: Is AXIS or CXF necessary for Java web services? Can it be all done via the JDK (1.6)?
Comment: Are you talking about calling or providing a web service?
Answer:
Is AXIS or CXF necessary for Java web services?

No. Although Axis2 is the most popular framework to work with Web Services is not the only way to do them.

Can it be all done via the JDK (1.6)?

Yes, but it is way much harder. You will benefit tremendously from using a framework used by others apps and from the bug fixes the development team provide. Doing all by hand is like reinventing the wheel.
If you want to have full control of what's happening underneath,  probably you could go with: JAX-WS
or if the application is very simple, directly with socket.
But again, Axis2 is the canonical way to do WS ( but not the only one )
Comment: Just a guess, but he probably wants a little more detail than that.
Comment: @Willliam: Edited to add more detail. I thinking that no matter what else is added at the end the answer will be the same. Is Axis necessary? No, Can be done with JDK? Yes, but it is much harder. : )
Answer: The following is based on an all to true and personal story:
So you want to consume a web service in your Java web application, and you don't want to add 10MiB of JARs to your lean 1.3 MiB .war file, and besides you are great at parsing XML (you can hand code XPath Queries, and XSLT files), you totally understand HTTP, and the client you are interfacing with has great documentation.  You download the WSDL look at your endpoints and your methods and start creating a Java class that maps to the features you are going to need. You feel great already.
They you start reading up on how to send a SOAP request and you think well this looks a little verbose but what they hey it's all just a string, so you start building a utility that takes your Java request object and converts it to a SOAP request.  You send your clear SOAP request to the server but it gets denied (missing a signature).
So now you start adding encryption JARs to your project and you start looking at how to calculate a signature of part of an XML document and include both it and the document in the request.  This takes you a while but with enough hacking you get a message that you can send to your soap service and you are now dealing with the SOAP response.  Now you are feeling great...
Until the admin at your client changes their security requirements, issues new public keys, and updates the soap interface with some custom types, and your next client who is running a similar service (but on a Windows Server) wants you to implement with them as well.
At this point I gave up trying to implement this in a pure Java way and just started using standard libraries.  They deal with stuff like encryption, marshaling, deviations form the standards and they let you focus on stuff that is closer to your problem domain.  I hope you can save yourself the lost month it took me to learn this lesson.
Answer: An update on the landscape of web services in 2013.
Web services used to be SOAP and XML-based. Web services were standardized into JAX-WS. Some of the more popular frameworks are (were):

Axis 1.x
Axis 2
Apache CXF - CXF also includes other protocols. It is a much broader framework
Metro Web Services which includes the JAX-WS Reference Implementation.
Java 6 and Java 7 include the JAX-WS RI by default. It means that frameworks are no longer needed except to generate client and service stubs / skeletons

There are other implementations not listed here that are vendor-specific e.g. IBM Websphere's WS implementation and Weblogic's WS implementation.
Generally though, to create web services, I would recommend Metro and the JAX-WS RI.
Note that there are many WS-* standards e.g. WS-Security which may not be part of all WS implementations.
Since web services have been around for a while, other alternatives have come up both in terms of architectural style, protocol, and encoding.
For instance, XML used to be the de-facto encoding. JSON is now more prevalent. It is worth looking into Jackson, a JSON parser, or Google GSON. The main arguments in favor of JSON are that it is easy to use, lightweight, and developer-friendly.
Along with JSON came REST. REST is an architectural style. With REST, you can still implement "web services" in the sense of remote services that can be easily consumed over a network. REST has also been standardized in the Java family of standards as JAX-RS. Some of the popular JAX-RS implementations include CXF, Jersey, and RESTLet.
Finally, there are some new kids on the block that use binary encodings. Those are Google Protocol Buffers and Apache Thrift. Their main goal is performance as well as broader support for other languages (Java, C#, Erland, Perl...).
When developing a web service today, the question should be:
 - do I care about performance?
 - do I want to access the service from many different languages?
 - do I want mobile-friendly?
These should help you guide your choice. Also, I prefer to keep my dependencies to a minimum. This means I would rather take something that is native to the JRE or JDK e.g. the JAX-WS or JAX-RS reference implementation.
Comment: Can you please update this answer for 2016? What has changed and what are the new standards? Do you have any blog posts that goes into more details on the same?
Comment: I would say that JSON, REST, and Jersey are the way to go: it is more lightweight and easier to use.
Answer: As an alternative to Axis, you can use the Spring WebServices framework to run your webservices application within a J2EE container like Tomcat or anything similar.  I've found it very easy to use and setup, and if you want to integrate your webservices into another web application later, it's quite easy to do (I've done so myself on two separate occasions).
Comment: Axis1?  Bad.  Axis2?  Even worse.  +1 for Spring web services.
Answer: You can use the http streams provided by the webserver as you whish, but using a framework and some jars (which are proven to work) will save you a lot of headaches and a lot of time in the long run.
Answer: Normally you will want to use a programming framework for web services.
Something like AXIS, CXF, or the Java EE (GlassFish) download from Sun.

Java Web Services - Is Axis Necessary?