Detect desynchronization in HOTP authentication
How does HOTP keep in sync?
Topological Circuit Simulator Does something like  exist for topological (eg. braided) circuits?   Alternatively, any ideas on how @ is getting  (or something similar)? Allow me to get notifications for new Meta posts, like mods do I'm currently helping out on . One of the most valuable things on new beta sites, especially private/early public betas, is Meta participation - see :  Treat Meta Questions Like Gold It’s not unusual for your meta site to receive significantly less traffic than the main site. The problems begin when you meta starts to get ignored by the community and ignored by the moderators. It is particularly disturbing when users reach out in meta and starts talking about improving the site or asking for help… only to be ignored; No follow-up, only deafening silence  Because of this, Diamond mods get a notification in their inbox for each new question on their Meta, helping ensure that each meta post is addressed. However, wouldn't it be great if Diamond mods weren't the only ones that could do this? The post does say that the community needs to be seeing these questions too. As an involved user, I would really like to be notified of these new questions - it would increase the good I could do the site. How about this?:  Of course, it would be opt-in, not opt-out, and per-site. A feature like this would greatly improve the good that enthusiastic site-builders can do for the site, and would, most likely, increase the overall chances of a site's success. How can I install Visual Studio? How can I install Visual Studio?    I'd prefer to use it in Wine or PlayOnLinux if possible. Fastest way to move Collection from Sharded MongoDB Cluster to a another Sharded MongoDB Cluster How many times has the matter in our solar system been recycled from previous stars? I've got a basic understanding of these facts:   The Universe is a little over 13 billion years old.  Our galaxy is almost that old. Our solar system is roughly 4.6 billion years old. The heavier elements (Carbon, oxygen, etc...) are only produced by stars.   When our solar system coalesced, the matter that makes up the planets came from a previous generation of stars.  (Meanwhile our Sun is busy making its own slightly-heavier elements, but those aren't ours.  Those belong to the next "generation" after our star dies.)  So we're all sitting on a rock whose matter was spewed out of a star (or stars) that preceded this solar system. But what I want to know is:  How many cycles of coalescing, fusing, nucleosynthesis, exploding -- and then repeating the cycle -- have this atoms in this ball of rock I'm standing on been through?    How do you know this?  Can you tell by the make-up of the matter in the solar system?  Looking around the Orion arm to see remnants of our former home? What does a linear transformation do to a vector in $\mathbb{R}^2$ $\newcommand{\Reals}{\mathbb{R}}$Doing some linear algebra. This question has me intrigued. I imagine it causes the vector to rotates the $x$ axis. But I mean, is there more to it?  $$ T_{A(\theta)}: \Reals^2 \to \Reals^2,\qquad A(\theta) =  \left[\begin{array} {rr}\cos \theta &amp; -\sin \theta \\   \sin \theta &amp; \cos \theta \\ \end{array}\right]. $$ What, geometrically, does the linear transformation $T_{A(\theta)}$ do to a vector in $\Reals^2$? multi-layer board copper pour I have a 6-layer board where the internal 4 planes are +15,GND,VCC,-15.  I was wondering if there was any advantage to doing a copper pour on the top and bottom layers?  I would probably leave them floating as I don't want to use micro-vias to say tie it to GND?    Is this actually a bad idea?  I.e. floating copper=antenna.  Would it be just as acceptable to have 4 layer board with the top layer having copper pour to VCC and the bottom having a pour to GND and keep the two internals as +-15?  Note that this is for a fairly low speed circuit which has some analog and digital parts. Recover data from SD card Non-https links to other StackExchange sites in User profile when using https How to bind 'touchstart' and 'click' events but not respond to both? Prediction in Cox regression I am doing a multivariate Cox regression, I have my significant independent variables and beta values. The model fits to my data very well.   Now, I would like to use my model and predict the survival of a new observation. I am unclear how to do this with a Cox model. In a linear or logistic regression, it would be easy, just put the values of new observation in the regression and multiply them with betas and so I have the prediction of my outcome.  How can I determine my baseline hazard? I need it in addition to computing the prediction.  How is this done in a Cox model? Triggered by a  I was wondering what actually would happen to a ship (e.g. the Enterprise-D NCC-1701) that collides with a stationary object such as a) another ship of a similar configuration or b) a gigantic structure like a moon or even a planet.  We know the deflector is supposed to keep interstellar dust (not to be confused with ordinary dust, which is a different thing) from ripping large holes in the ship.  At first, one thinks "Obvious. ." But does it really? Would the deflector manage to actually deflect both masses? If not, where is the threshold of what a deflector can handle? Would the ship maybe tunnel right through the object, because of wibbly-wobbly space wobblification by the warp field? It does do some weird things to the space right in front and behind the vessel.  Important remark: We cannot approach this with what we know about physics at all. For all intents and purposes, both ships must measure the other ship travelling faster than light, resulting in it having infinite (or rather undefined) mass and by extension momentum. If we start with that reasoning any ship jumping to warp would suck in the entire universe (it takes a moment, but think about it). So, obviously we cannot apply our intuition (even our relativistic intuition) here. Beamer: bold math no longer working I have a VIP skybag (I believe this does not matter). It has a 3-number TSA lock built into the suitcase. I know the combination to unlock, let's say it's 345. Recently it was locked and while there was a different number on the combination lock the reset/set lock button was pressed.  Since then the reset/set lock button is pressed (stuck) and the lock button also does not unlock. Any pointers on how to unlock it? I am thinking of unscrewing the lock from inside of the suitcase but it seems quite a hassle, as I may have to assemble it back. Let me know if there is any other option to unlock it from the outside. USB WiFi dongle device that can emulate a virtual mass storage device for a home video player Is there a USB WiFi dongle device that can:   Emulate a virtual mass storage device for a home video player But in fact shows the files from a network-shared folder? When I save a file (e.g. Images) to a folder which already exist there, Chrome adds a (N) where N is first available number. This causes I have multiple copies of same file! How can I disable Chrome's auto file renaming?   Thanks How do you turn off developer mode on an s5? I turned developer options 'off', but is there anything else that needs to be done? Not my phone so don't want to mess anything up :-) Is it true that the order of $ab$ is always equal to the order of $ba$? How do I prove that if $a$, $b$ are elements of group, then $o(ab) = o(ba)$?   For some reason I end up doing the proof for abelian(ness?), i.e., I assume that the order of $ab$ is $2$ and do the steps that lead me to conclude that $ab=ba$, so the orders must be the same. Is that the right way to do it? Property of $\{0^n, 1^n, \ldots\}$ The differences between adjacent squares are the odd numbers:  0 1 4 9 16 25 …  1 3 5 7  9 …  The differences between adjacent odd numbers are 2 = 2!  I found that this truth is more general: If the differences between adjacent powers of $n$ are written out, and the differences of those differences etc, the $(n+1)$th sequence is {n!, n!, …}  Is this a well-known theorem? Does it have an easy proof? Compiling with g++ using multiple cores