Ask HN: Going to Grad School, which language/framework should I learn? - <AUTHOR>

I have been programming in C# for about 4 years at work. I plan to go back to grad school for a masters in CS next year, what language should I learn to help me out with grad school courses?<p>Update: To be clear, the purpose of going to grad school is to sharpen up and most likely to go back into the workforce later. <comment><USER2> Grad school is writing and reading papers, not writing code (most of the time). Learn LaTeX and subscribe to ACM digital library and get to reading. You're expected to have programming skills in advance (at least where I went) but you should be language indifferent. Read SICP and learn the basics of C, C++, Java and Python.

<comment><USER3> I'll second this. If you never get into LaTeX (I didn't) you'll always feel vaguely embarassed when showing your .doc thesis alongside the LaTeX formatted papers presented by your peers.

Now that I'm out of school it rarely comes up but while I was working on my Master's it was a constant irritation.

</comment></comment><comment><USER3> Clojure:

\- Functional programming is sufficiently different from C# to expand your mind in a good way. New paradigms will make you a better programmer even if you stick with C# in the end.

\- Open source foundations allow you to get all the tools you need for free.

\- Java interoperability gives you access to libraries you'll need for specialized projects.

\- Clojure is growing and has an excellent community on Google Groups and on Freenode IRC.

<http://clojure.org/>

</comment><comment><USER4> You shouldn't be thinking languages, you should be thinking concepts. Take a look at your course schedule, find books and papers on those topics and get cracking. Your software development skills will probably be superior, or at least way more than is needed for a grad program. If all you know is how to write code, you'll have a tough time expressing the concepts you are learning in the classroom.

</comment><comment><USER5> If you have 4 years of experience in C#, stick with C#! It will be tough, but most of the people in academic environment don't have professional experience as developers... so you should be ahead of them with your C#.

</comment><comment><USER6> You don't say what you are going back to grad school for? Masters in CS?

<comment><AUTHOR> Sorry, it is a masters in CS, corrected my question.

</comment></comment><comment><USER7> C/C++, Python ?

<comment><USER2> there are some significant libraries in java, like swarm</comment></comment>


Refal programming language - <AUTHOR> http://en.wikipedia.org/wiki/Refal

<comment><USER2> Interesting, especially in comparison with SNOBOL. Although I am always wary of claims like _a typical program in Refal is on average two or three times shorter and more readable than a Lisp analog_. That might be true of programs written in Refal because it suits the domain, but I would be surprised to the core if general-purpose Lisp programs could be rewritten in Refal and become 2-3 times shorter and become more readable.

</comment><comment><USER3> If this looks interesting to you, you might also like Pure: <http://code.google.com/p/pure-lang/>

<comment><USER4> Thanks! This is exactly what I've been looking for. A dynamic language with Haskell-like syntax.</comment></comment>


Meteorite crash in Russia - <AUTHOR> http://rt.com/news/meteorite-crash-urals-chelyabinsk-283/ <comment><USER3> Here's a collection of insane videos of the event, some with the enormous sonic boom:

<http://www.youtube.com/watch?v=XIAm5hq8WWc> <http://www.youtube.com/watch?v=b0cRHsApzt8> <http://www.youtube.com/watch?v=Np_mpGYSBSA>

Can anyone translate what they are saying in the first one?

You can get a good idea of the new videos being posted using YouTube's "last hour" filter:

[http://www.youtube.com/results?search_query=%D0%BC%D0%B5%D1%...](http://www.youtube.com/results?search_query=%D0%BC%D0%B5%D1%82%D0%B5%D0%BE%D1%80%D0%B8%D1%82%D0%B0&filters=hour&lclk=hour)

<comment><USER4> Here's a great dashcam video that captures the meteor arcing across its field of vision and lighting up the scene more brightly than the sun like a nuclear blast (first submitted to HN by dennisgorelik). I almost thought it was a hoax, and even tried to examine the video for signs that it was CGI.

<http://www.youtube.com/watch?v=tJOJ6B2XOyA>

The guy doesn't even say anything for a long while, just starts speeding up.

edit: Phil Plait of Bad Astronomy (Slate) think it's unrelated to the 2012DA14 asteroid, because of the timing gap and incorrect direction of travel. [http://www.slate.com/blogs/bad_astronomy/2013/02/15/breaking...](http://www.slate.com/blogs/bad_astronomy/2013/02/15/breaking_huge_meteor_explodes_over_russia.html) This could have turned out very badly if the thing had hit the ground...could we have caught this one, and why didn't we?

<comment><USER5> Can anyone explain why I see so many dashcam videos from Russia?

<comment><USER6> Corruption.

* Pedestrians are corrupt -- they throw themselves in front of your car then sue for damages.

* Other motorists are corrupt -- they lie about the accident facts

* Cops are corrupt -- easily bought off and bribed (or tapped through nepotism)

<comment><USER7> this was the exact explanation given by a driver with a dashcam to me. in russia, most police do not feel responsible to organize traffic, help solve deadlocks, and give service to citizens. they behave like a mob entitled to rob you in a various ways due to false,confusing interpretation of legal texts.

</comment></comment></comment></comment></comment><comment><USER8> I happen to live 300km from the epicenter. The meteorite was seen in home town as well. I made a list of all the videos I could find: <http://say26.com/meteorite-in-russia-all-videos-in-one-place>

<comment><USER9> The video of the loading dock door blowing in is extraordinary.

<comment><USER10> And of course it's the only one that seems to have been removed.

</comment></comment></comment><comment><USER11> It takes events like this to highlight how awesome it is to have a large number of people constantly recording video. Integrated dashcams with a circular buffer should become ubiquitous standard equipment IMO.

1080p of first clip available on YouTube: <https://www.youtube.com/watch?v=7c-0iwBEswE>

<comment><USER12> Does everyone in Russia have a dashcam or something? It seems like every other video I see on YouTube was recorded on one, and yet I don't know of anyone in Japan or the US with one installed (parking cams don't count). It's a great idea– I would probably get one if I still had a car, but it's amazing to me just how prevalent they _seem_ in Russia. (Elsewhere too? I don't know. I'd love it if someone could enlighten me.)

<comment><USER13> Yes apparently to avoid people jumping infront of car and suing the driver: <http://www.animalnewyork.com/2012/russian-dashcam/>

<comment><USER14> No, not because of the jumpers.

It's to capture the car to car accidents and the road rage incidents. Too many people have bought their driving licenses and drive as if they are the only people on the road. Too many of these come from the criminal background and won't shy away from expressing their dissatisfaction with your driving ethics and what not. Now there's a dashcam for that.

</comment></comment></comment></comment><comment><USER15> That is an amazing event. I am not sure I buy the meteorite story. Has anyone checked on 2012-DA14 [1] the asteroid that was supposed to cross between the earth and geosync orbit this evening? One conjecture would be it knocked something out of orbit.

The air defense stuff is somewhat hard to believe, we don't intercept de- orbiting space junk, much less less hypersonic meteors. Further every missile interceptor that is publicly disclosed (which includes the US attempts at an exo-atmospheric interceptor) have boost stages that generate a lot of vapor, there is no rising vapor trail in any of the videos of a ground based interceptor.

Finally there is the magnitude of the flash. Given the lack of sparkles on the video I don't believe what ever exploded was nuclear but on the videos with timers watching the flash and timing the 'boom' correlates with the 20 - 25 km (80,000') in altitude. One hopes it wasn't a surveillance aircraft that was destroyed. I'm sure if it was we'll hear about that in the morning.

Definitely a mystery.

[1] [http://www.guardian.co.uk/science/across-the- universe/2013/f...](http://www.guardian.co.uk/science/across-the- universe/2013/feb/15/asteroid-2012-da14)

<comment><USER16> This guy <https://twitter.com/BadAstronomer/status/302313851511271426> seems pretty sure it's unrelated to 2012DA14. And he has 230K followers on Twitter, so ... _shrug_

<comment><USER17> I think it's a really bad idea to start using Twitter followers as a credential. That being said Phil Plait is a legit astronomer and has a Ph.D in Astronomy and worked on the Hubble Telescope and has done a TED talk on defending Earth from asteroids. With real credentials like those you're doing a disservice to first mention the number of Twitter followers to validate his expertise.

<comment><USER18> I'm pretty sure mentioning the amount of twitter followers he has as credentials was a joke, but I agree with your point. I don't think anyone would contend the fact that Ashton Kutcher had the final say in all matters.

<comment><USER16> For the record, my _shrug_ was meant to acknowledge that Twitter follwers was an absurd way to judge the credibility of an astronomer.

But he also has a blog on Slate.

</comment></comment></comment></comment></comment><comment><USER19> >According to unconfirmed reports, the meteorite was intercepted by an air defense unit

Anyone else catch this? Is this just a bad translation and they mean to say that an air defense unit tracked the meteorite on radar?

I wouldn't think any air defense system would be capable of actually intercepting a meteorite, but perhaps I'm wrong. Still doesn't seem like anything intercepted it from the videos.

<comment><USER20> A meteorite would be hypersonic when first entering the atomsphere and then supersonic the rest of the way until maybe a few hundred meters before impact. Besides that, if it's not a solid iron-nickle meteorite, it may even breakup or explode well above the surface instead of staying intact.

It's not quite like taking out a satellite in low Earth orbit in that there's plenty of information on its orbit, trajectory, tumbling characteristics, approximate mass etc... It would be very, very, very hard to intercept a meteorite without a lot of information before it even got close to Earth.

The report of a missile salvo taking it out is very suspect IMO. Without more information, it's hard to tell.

<comment><USER21> I don't know about "taking it out" per se but an air defense system designed to hit ballistic missiles in the terminal phase could also hit an inbound meteorite. It is within the performance envelope of those types of systems. That said, against a meteorite it won't do much good since it is an inert mass.

It is plausible that the Russians launched an interceptor just to be safe. If it is a meteor, it neither hurts nor helps. If it is a man-made structure, it will do some real damage to it. Either way they can always argue "better safe than sorry".

<comment><USER20> Russians have scientists working on the meteorite problem, but I doubt the military would do a hail Mary launch on this. If anything, they would much rather let it fall intact than risk having it break up and spread damage to a much larger area. But that still assumes they can respond quickly enough or had missiles on standby with weapons that can affect a meteorite (not specifically ballistic reentry capsules, but actual meteorites). There's a worrying thought.

It may be hot enough for infrared seekers, but it's no jet. Jets are fragile by comparison so, unless they had purely kinetic weapons... but that's still speculation at this point. We still don't know what the Russians did or if they did anything at all.

I doubt they even knew this specific meteor would enter the atmosphere. It's already hard enough detecting much bigger rocks in Earth-crossing orbits.

<comment><USER21> It does seem silly to intercept. The computers could ascertain that the trajectory was unlikely to have originated on Earth in milliseconds.

Modern terminal guidance systems are all imaging based. Or at least the US ones have been for a couple decades; I imagine the Russians are using something at least vaguely similar.

Basically, the missiles latch onto the target visually and are capable of recognizing their target from the details of its appearance (in an air defense context, not just "an airplane" but "that _specific_ airplane"). It is why, contra Hollywood, modern terminal guidance systems are nigh impossible to spoof. The missile knows what the airplane looks like and can read the tail number off your craft, so as long as it can locate it (even if it temporarily loses sight), it is likely to hit unless the motor runs out of gas. Heat has little to do with it, though the imagers often work in broad spectrum infrared.

Lots of smaller, impacters with kiloton-class impact energies are never discovered or discovered at the very last minute. This looks like a pretty small rock in terms of damage done so it could easily have been missed by sky surveys.

</comment></comment></comment></comment></comment><comment><USER22> From the videos, this was almost certainly a metallic meteorite (stony meteorites rarely survive their flight through the atmosphere). And it's very likely that part of it got to the ground intact. Get ready for stories about recovering a lot of meteorite material in the next few days.

The contrails, and the videos, show that the meteorite (or pair of meteorites) grew very hot, but survived at least in part and probably fell to the surface. I would love to see the recovery effort.

Notice the long delay between recording the image of the contrail and the sonic boom. This reveals how high the meteorite's path was at the location of the recording.

</comment><comment><USER23> Maybe this will help people appreciate that space is not some other world on TV, instead _we are in space right now_. Yes, it can reach out and touch us.

<comment><USER19> Just to be pedantic for the hell of it, we're really in space-time, and it's that "time" dimension that makes "space" capable of reaching out and touching us :D

<comment><USER24> That's not being pedantic. That's mixing up "space" as in "the region of space above the heaven, for most part consisting of vast emptiness and occasional celestial bodies" and "space" as the "A continuous area or expanse that is free, available, or unoccupied" and of course it's technical usage in physics. And this is being pedantic for the hell of it :-)

</comment></comment></comment><comment><USER25> FYI, if you see photos of a burning crater, those are fake. That's the Door to Hell, in Turkmenistan. <http://en.wikipedia.org/wiki/Door_to_Hell>

<comment><USER26> Well that's a relief.

A door to hell is a lot less scary than a meteor crater.

</comment></comment><comment><USER27> Is it really just a coincidence that this happened the same day as the 2012DA14 asteroid? Some news articles are saying this came from the other direction and that these kinds of smaller asteroids hit 5-10 times a year, and while I put a low trust in my memory I don't recall seeing this stuff all over the news (and at the top of HN!) every couple of months... Or is that true but normally they land in the ocean or unpopulated areas and this one just _happened_ to hit an area with lots of dashboard cams and just _happened_ to occur on the same day as the 2012DA14 flyby? I'm sure less probabilistic things have happened in the history of the universe, but I'm still very curious. Or is it soon to do much but speculate?

<comment><USER28> Yeah, it is a coincidence. It was debunked pretty early on, mainley because the direction it is flying in exactly the opposite direction the 2012DA14 will be flying in.

<comment><USER29> Also the only reason its getting press is the video most likely. That really helps at getting the reptile brain attention of viewers.

</comment></comment></comment><comment><USER30> It's amusing how fast the shadows are in those videos: <http://www.youtube.com/watch?v=Qin41lP9r2U> <http://www.youtube.com/watch?v=lgBZMsaEN6s>

</comment><comment><USER31> _It is believed that the incident may be connected to asteroid 2012 DA14, which measures 45 to 95 meters in diameter and will be passing by Earth tonight at around 19:25 GMT at the record close range of 27,000 kilometers._

apparently there was a risk that asteroid would intercept a satellite orbit. Too early to say, but it seems more likely than mere coincidence.

<comment><USER32> Phil Plait (Slate's Bad Astronomer) doesn't think they're related: <https://twitter.com/BadAstronomer>

Note especially: _12 hours is a long way at 8 km/sec, so this object in Ruissia was on a very different orbit than 2012 DA14._

and also: _Also, apparently moving east-to-west tho I can't say for sure. Anything on the orbit of DA14 would be moving south-to-north._

Obviously info is still pretty thin, and this article seems pretty speculative. I'd wait a few hours before jumping to any conclusions.

<comment><USER31> Good catch, thanks for the additional data. Could be I'm too eager to see a pattern where none exists.

</comment></comment></comment><comment><USER25> The explosion is clearly audible 25 seconds in to this clip: <http://www.youtube.com/watch?v=Np_mpGYSBSA>

<comment><USER33> Great video except for the Vertical Video Syndrome [1]. Is that glass breaking right after the shockwave? I wonder what kind of overpressure it generated.

eta: ghshephard posted a link to a better video with the clear sound of glass breaking. <https://news.ycombinator.com/item?id=5224858>

[1] <http://www.youtube.com/watch?v=Bt9zSfinwFA>

<comment><USER34> Maybe the sound that we heard traveled faster than the acoustic waves that broke the glass due to having different frequencies.

<comment><USER22> > Maybe the sound that we heard traveled faster than the acoustic waves that > broke the glass due to having different frequencies.

Unlikely. A powerful sonic boom could cause all that damage, and collapse an aging brick structure, and yet travel at or near the speed of sound.

</comment></comment></comment></comment><comment><USER35> I suspect the meteorite and earthquake are not related. The only recent earthquake that fits your description was M6.6 at 67.580°N 142.593°E [1], that's about ~2630 miles away from the reported meteorite impact in Chelyabinsk, Russia [2].

[1] [http://earthquake.usgs.gov/earthquakes/eventpage/usc000f76f#...](http://earthquake.usgs.gov/earthquakes/eventpage/usc000f76f#summary)

[2] [http://hosted.ap.org/dynamic/stories/E/EU_RUSSIA_METEORITE?S...](http://hosted.ap.org/dynamic/stories/E/EU_RUSSIA_METEORITE?SITE=AP&SECTION=HOME&TEMPLATE=DEFAULT)

<comment><USER22> > I suspect the meteorite and earthquake are not related.

It wasn't an earthquake -- it was a very powerful sonic boom, and yes, it was caused by the meteorite's passing. A similar sonic boom flattened hundreds of square miles in Tunguska in 1908, after a much larger space object fell there:

<http://en.wikipedia.org/wiki/Tunguska_event>

<comment><USER35> The title was changed. The original said there was a meteorite strike, followed by a 6.7 earthquake.

</comment></comment></comment><comment><USER36> This site has an image of a hole in the ice of Lake Chebarkul: <http://say26.com/meteorite-in-russia-all-videos-in-one-place>

Here's the lake: [https://maps.google.com/maps?q=lake+chebarkul&hl=en&...](https://maps.google.com/maps?q=lake+chebarkul&hl=en&sll=54.879767,60.523682&sspn=2.101643,3.232727&t=h&gl=us&hnear=Chebarkul+Lake&z=12)

~40 miles due west of Chelyabinsk and a little south.

</comment><comment><USER37> Wow, do you know how lucky we all are? Silly little shit like this could easily start WW3.

We need complete ICBM disarmament. They can keep their bombs and we can keep ours (for now), but we should restrict delivery systems such that there is a built in lag (bombers taking many minutes or hours to reach their targets), and can be recalled. ICBM's can be launched in a moment, and it is impossible to recall them or disable them once they are underway.

<comment><USER38> No sane military would introduce such a lag. Furthermore I think your concerns are overblown. After all, something far more "potentially disastrous" happened in 1983 at a high point in Soviet/US tensions, and fortunately the guy in charge of retaliation launching had the common sense to reason a war wouldn't be started with one (or in his case, 5) missiles. <http://lesswrong.com/lw/jq/926_is_petrov_day/>

<comment><USER39> Another problem with a "long fuse" approach: It offers either antagonist a (seemingly) low-cost path of escalation (say, "just" deploying the ICBMs to their silos) during a crisis. This not only necessitates a comparable response, it is subject to being interpreted as more belligerent than intended. After you've gone a few rounds of this, you're right back where we are now, launch keys always ready to turn, except this time you're riding the momentum of mounting brinksmanship.

</comment></comment></comment><comment><USER40> When you look at a commercial jet flying at 10k meters from the ground, it takes a long while until it disappears from the skyline. This meteorite crossed the entire skyline in a matter of seconds. That's just mind bogging. Also, the sound blast arrived waaay after the main explosion, and since it's been traveling at ~360 meters per second. I wonder if anyone here could estimate the speed of that rock in the atmosphere.

</comment><comment><USER3> If this isn't some hoax, this is pretty wild. I'm not sure, but the general volume of news about this seems to point to it being real.

There's more information on this page here: [http://www.russianmachineneverbreaks.com/2013/02/14/what- is-...](http://www.russianmachineneverbreaks.com/2013/02/14/what-is-happening- in-chelyabinsk/)

</comment><comment><USER41> Nowhere on the linked page is there any reference to a 6.9 quake. There wasn't an earthquake of any kind, although, "Witnesses said the explosion was so loud that it resembled an earthquake and thunder at the same time..."

I'm not sure what I'm supposed to believe anyway. Wasn't the rule that RT is considered accurate on any stories _not_ involving Russia?

<comment><USER11> Yeah, 6.9 is not mentioned in the story and USGS does not show any recorded event there. Russian media was saying nothing hit the ground -- there was just an explosion in air which is seen in the video. I'm sure _something_ hit the ground, though.

</comment></comment><comment><USER42> I can't get over how long it takes for the sonic boom to hit. This video has the meteorite trail on camera for 27 seconds before you hear the boom: <http://www.youtube.com/watch?v=Np_mpGYSBSA>

How fast does something have to be travelling to build up a delay like that?

<comment><USER23> While it's moving at great speed, it's really about distance that determines the gap with sonic booms. Speed of sound is ~340m/s at sea level, so using that value with a gap of 27 seconds we can assume the boom originated ~9.1km away from the camera(thus it took 27 seconds for the sound to reach the camera). The distance is probably wrong given the speed of sound is different depending on the altitude.

The speed had more to do with the magnitude of the boom itself.

<comment><USER43> And to be clear, there isn't any one "boom" event with a sonic boom. It is an ongoing event for stationary observers, a pressure front that follows the object and is heard when it passes by you.

<comment><USER23> Very true. That effect is very pronounced with this one in particular. Would have been truly awesome to experience in person, if not for the possible hearing loss.

</comment></comment></comment></comment><comment><USER44> I don't get why everyone seems to be running _out_ of (what appear to be) fairly sturdy concrete buildings and into the street. Sure, a building won't protect you from an incoming meteorite of any size, but being indoors might protect from fragments if an incoming meteor hits something else.

<comment><USER45> Why not run outside? I haven't heard anyone killed by meteorites, so I wouldn't consider them very threatening. If it's not threatening then why not go out and enjoy the show?

<comment><USER22> > I haven't heard anyone killed by meteorites, so I wouldn't consider them > very threatening.

Just for the historical record, an Egyptian dog was allegedly killed by a meteorite:

<http://en.wikipedia.org/wiki/Meteorite>

Quote: "The most infamous reported fatality from a meteorite impact is that of an Egyptian dog that was killed in 1911, although this report is highly disputed."

Another quote: "The first known modern case of a human hit by a space rock occurred on 30 November 1954 in Sylacauga, Alabama.[41] There a 4 kilograms (8.8 lb) stone chondrite[42] crashed through a roof and hit Ann Hodges in her living room after it bounced off her radio. She was badly bruised."

She was also extremely fat, and the meteorite grazed her ample side. I'll bet it motivated a soul-searching consideration of a weight-loss program:

[http://blogs.funeralwise.com/dying/files/2012/05/Anne- Hodges...](http://blogs.funeralwise.com/dying/files/2012/05/Anne-Hodges.jpg)

</comment></comment></comment><comment><USER46> Excellent video of some crowd reactions - <http://www.youtube.com/watch?v=b7mLUIDGqmw>

Has someone running, after the boom, comes across crowds being directed out of buildings. You can almost sense that they really have no idea what's going on.

</comment><comment><USER47> Side issue: Anyone know what a Google Driverless car would make of a fireball heading towards it out of the sky? Is there a default action in case of uncertainty? Brake? Swerve? Any of those by these drivers could have been worse than the "yebat"

<comment><USER48> This would be a case where the driver would be expected to take over.

<comment><USER47> Car Voice: Yebat! There's a freaking asteroid heading down the road. On the wrong side! Bloody Thrun never had a test case for this. Sod it. You drive ....

:-)

Thank you, I needed a good laugh

Edit: I have real work I should be doing: <http://i.imgur.com/usRX31z.jpg>

<comment><USER47> Having now caught up on the actual damage done (500 injured, thousands without windows in a Russian winter) I regret this light-hearted take - <USER2> consider it deleted until I can find some way to actually delete it.

</comment></comment></comment></comment><comment><USER49> I was wondering why there are so many dashboard cams. Answer: from the NYTimes

"Some of the numerous videos that quickly emerged of the incident highlighted a distinctly Russian phenomenon: the dashboard cam. As Business Insider recently pointed out, they are commonplace in Russia partly because of the dangerous driving conditions that lead to so many accidents, and with an unreliable police force such cameras can provide valuable evidence following a crash."

[http://thelede.blogs.nytimes.com/2013/02/15/video- captures-f...](http://thelede.blogs.nytimes.com/2013/02/15/video-captures- flaming-object-believed-to-be-meteorite/?smid=tw-share)

</comment><comment><USER50> It's amazing how something so tiny can illuminate the entire sky like that.

<comment><USER25> I'm not convinced it was tiny.

</comment></comment><comment><USER51> Did NASA have this on their list of objects they were tracking, and did they see it going down as it did? (I'm not suggesting that they should have been able to predict it.)

It's amazing that we have so much coverage of this.

I really hope someone somewhere is making a life size mockup of this object, and then showing on a map what damage would be done by bigger objects.

"This is what something the size of a car would do"

"This is what something the size of a house would do"

"This is the average size of the biggest 5% of the objects that we track in Earth orbit, and here's the damage that'd do".

(A bit like that atomic bomb map).

</comment><comment><USER45> With all these videos, I wonder if Photosynth-style 3D reconstruction of the scene would be possible. That would be very interesting to look at.

</comment><comment><USER52> A couple of years ago a smaller meteor blazed over the western United States, lighting up large parts of Utah ([http://www.ksl.com/?nid=148&sid=8714738](http://www.ksl.com/?nid=148&sid=8714738)), but lacking the sonic boom. I did see the Utah meteor directly, and I imagine that today's was significantly more awesome and more terrifying.

</comment><comment><USER53> We are compiling coverage, videos, etc. in a single place on Referly (obviously there are NO product links) - including many links found here. Would appreciate any contributions, suggestions, translations and feedback:

[http://refer.ly/meteor-over- russia/c/15aeda3c773d11e2bfbf220...](http://refer.ly/meteor-over- russia/c/15aeda3c773d11e2bfbf22000a1db8fa)

<comment><USER44> I wish you would put a B612 Foundation link on there (which is sort of a product link, I guess)

</comment></comment><comment><USER54> I can't help but notice this is only a few positions above the large hadron collider shutting down story. Correlation?

<comment><USER55> Correlation is high. Causation is low.

</comment></comment><comment><USER56> Do meteorites really do this? I've never heard of another like this event before, and I always hear reports about meteors 'almost' hitting earth well in advance of the possible collision date.

I didn't think the sky could simply open up and rain down hellfire without anybody spotting it beforehand.

<comment><USER22> > Do meteorites really do this? I've never heard of another like this event > before ...

In that case, it's time for you to read about Tunguska in 1908:

<http://en.wikipedia.org/wiki/Tunguska_event>

<comment><USER57> that thing was no joke

</comment></comment></comment><comment><USER58> Yet another compilation of all the videos here: <http://www.comandotibidabo.com/meteoritos-urales/>

I've been amazed by how huge the explosion is being so far away from the meteorite crash.

</comment><comment><USER31> Yikes, >500 people injured: [http://www.reuters.com/article/2013/02/15/us- russia-meteorit...](http://www.reuters.com/article/2013/02/15/us-russia- meteorite-idUSBRE91E05Z20130215)

:-(

</comment><comment><USER59> [http://www.slate.com/blogs/bad_astronomy/2013/02/15/breaking...](http://www.slate.com/blogs/bad_astronomy/2013/02/15/breaking_huge_meteor_explodes_over_russia.html)

<comment><USER59> "Preliminary indications are that it was a meteorite rain," an emergency official told RIA-Novosti. "We have information about a blast at 10,000-meter (32,800-foot) altitude. It is being verified." [http://www.reuters.com/article/2013/02/15/us-russia- meteorit...](http://www.reuters.com/article/2013/02/15/us-russia-meteorite- idUSBRE91E05Z20130215)

</comment></comment><comment><USER60> Nature article: [http://www.nature.com/news/russian-meteor-largest-in-a- centu...](http://www.nature.com/news/russian-meteor-largest-in-a- century-1.12438)

</comment><comment><USER61> compilation of different videos

[http://www.youtube.com/watch?feature=player_embedded&v=5...](http://www.youtube.com/watch?feature=player_embedded&v=5BuXRYuPP3M)

</comment><comment><USER62> They are confused on what's going on and cursing badly :)

</comment><comment><USER63> And the second stage of HAARP testing concluded.....

</comment><comment><USER64> place where meteor crashed is only 100 miles from me but I got to know about it today from web-news :)

</comment><comment><USER65> Half life 3 viral video campaign... ?

</comment><comment><USER66> Insane!

</comment><comment><USER67> that's how we roll

</comment><comment><USER68> OMG... That is scary!

</comment><comment><USER69>
      8:10 GMT: Oleg Malkov, an aerospace scientist at
      Moscow State University, told Komsomolskaya Pravda
      newspaper   that the meteorite went undetected by
      space scanners,   likely because it was coming from
      the direction of the Sun.
      "We can only register stones coming from the
      direction of the night sky," he explained. Malkov
      confirmed that   the meteor shower in the Urals
      was not connected to the 2012DA14 asteroid that
      will approach Earth in a few hours.

      7:46 GMT: Ekaterinburg's observatory has officially
      deemed the incident a fireball meteor shower. No
      evacuations were called for, and radiation levels
      were determined to be normal.

      Source:
      http://rt.com/news/russia-meteor-meteorite-asteroid
      -chelyabinsk-291/

<comment><USER70> That is terrifiying.

</comment></comment><comment><USER69>
      9:36 GMT: There is a high chance that another
      meteorite could enter the Earth's atmosphere in
      the next few hours, Sergey Smirnov from Pulkovo
      Observatory told Vesti news channel.

      9:07 GMT: "The object could be about a meter
      in diameter and weigh a few tons," Valeriy Shuvalov
      of the Institute of Geosphere Dynamics told
      RIA-Novosti.
      "As it entered the atmosphere, it broke into a
      cloud of pieces that flew on, creating a blast wave
      and emitting light. That's where the flashes came
      from, as well as broken windows. Most of the
      object's material evaporated, the remaining pieces
      slowed down and fell. It was most likely of iron
      nature as it penetrated so far through the
      atmosphere.
      However, we still don't have the exact data on
      the debris."

Source: [http://rt.com/news/russia-meteor-meteorite-asteroid- chelyabi...](http://rt.com/news/russia-meteor-meteorite-asteroid- chelyabinsk-291/)

<comment><USER71> > a high chance that another meteorite could enter the Earth's atmosphere in > the next few hours

can you get another source than RT? they seem to aim for senation first, accuracy second

</comment></comment><comment><USER69> Image updates as of 3:30 AM ET

      http://goo.gl/V7491
      http://goo.gl/4Rqk0
      http://goo.gl/WHR65
      http://goo.gl/PUH6q
      http://goo.gl/qlXE3
      http://goo.gl/LRD52

</comment><comment><USER30> Too bad this meteorite didnt crash in Sochi. Could've helped covering the Olympics constructions thefts.

</comment><comment><USER72> So, uh, NASA was expecting this. They were going to have a livestream chat about this? Er, looks like they got the prediction slightly off.

[http://www.nasa.gov/mission_pages/asteroids/news/asteroid201...](http://www.nasa.gov/mission_pages/asteroids/news/asteroid20130201315144.html)

*For the person who downvoted me, there is supposed to be a near earth flyby tomorrow of an asteroid called 2012 DA14 which will be livestreamed with commentary by NASA here: <http://www.ustream.tv/nasajpl2>. A reasonable explanation would be that the event today was a chuck or asteroid as part of that expected fly by. The astroid is expected to be 17,000 miles away from Earth.</comment>


I am learning Python 3 and blogging about my journey - <AUTHOR> https://www.ploggingdev.com/ <comment><AUTHOR> I recently started learning Python 3 and decided to blog about the journey primarily because it forces me put down what I learn in words, and it also serves as a quick reference for when I need to lookup something Python related.

Learning Python has been a very pleasant experience so far. Things I found enjoyable: dynamic typing, code readability, multiple programming paradigms it allows, not verbose (looking at you Java).

I covered the basics of the language so far, and I am yet to explore the libraries available and GUI frameworks such as Kivy. I will be building small programs to better understand the language. Some ideas: blackjack, tictactoe and I will blog about how I go about building them.

Feedback is welcome!</comment>


Warning: Pokemon GO Is a Death Sentence If You Are a Black Man - <AUTHOR> https://medium.com/mobile-lifestyle/warning-pokemon-go-is-a-death-sentence-if-you-are-a-black-man-acacb4bdae7f#.o6totuml5 <comment><AUTHOR> _I spent less than 20 minutes outside. Five of those minutes were spent enjoying the game. One of those minutes I spent trying to look as pleasant and nonthreatening as possible as I walked past a somewhat visibly disturbed white woman on her way to the bus stop. I spent the other 14 minutes being distracted from the game by thoughts of the countless Black Men who have had the police called on them because they looked "suspicious" or wondering what a second amendment exercising individual might do if I walked past their window a 3rd or 4th time in search of a Jigglypuff._</comment>


To iOS 6 Maps Haters: Settle Down, Beavis - <AUTHOR> http://afitnerd.com/2012/09/23/settle-down-ios-6-maps-haters/

<comment><USER2> They could have done integration without changing or runining the maps. But that was not decision (either because Google cut them off or because Apple did not want to continue negotiating with Google). And you know why the integration makes matters even worse? Because as there is no similar features to intents on Android, when you click on a direction on iOS it will always open it on Apple Maps, even if it doesn't find anything or show you London in Oklahoma when you are in the UK.

Secondly, AFAIK, the old Maps app was also done by Apple themselves, using Google's technology. The lack of features is not Google's fault, but Apple's. The same happened with the YouTube app, that was really behind Android, until Apple decided it was no longer developing it and Google took over. Seeing how Google behaves, I'm pretty sure that if they had the chance to add turn-by- turn navigation to the iPhone they would have done so.

<comment><USER3> The lack of features in Maps was due to Google's restrictions in their api. It specifically prohibits turn by turn applications using their api. We also have no idea nor will we ever know if and what terms Google wanted to license Google Maps.

<comment><USER2> Well, yeah, that could be it. But that restriction is just on the general ToS and I don't think Apple was bound by that. And I think that both Google and Apple could have agreed to let Apple maps use turn-by-turn, disregarding the API ToS.

I find it hard to believe that Google did not want iPhones to have turn-by- turn. In their minds, the more people use their services the better. And I never saw one piece of evidence of Google crippling a product on iOS so people buy Android.

</comment></comment></comment><comment><USER3> Same experience for me with the new Maps app. It worked great for me. Very impressed by the integration of the turn by turn navigation. There is a lot of work to be done to catch up to Google maps, but this is a decent start.</comment>


The Geek Code - <AUTHOR> http://www.geekcode.com/

<comment><USER2> "Geek" nowadays means "has a Captain America Shield iPhone otterbox".

<comment><USER3> Geek = cheerleader who owns a pair of glasses that she sometimes wears when she doesn't have any contacts available.

Or is that a nerd?

<comment><USER4> Geek.

</comment></comment></comment><comment><USER5> Geez, I remember having my Geek Code in forum sigs, ircbots spitting them out on whois, etc.

<comment><USER6> I remember having it in a Usenet X-header...

</comment></comment><comment><USER7> Ah, memories. A lot has happened over the past several years that could be added to the code.

Having said that, GCS/MU d-- s-:++ a C+++$ UL+(+++) P+++ L++ E--- W+++ N++ w+ M++ PS+ PE++ Y+ PGP- !t X-- R++ tv-- b+ DI++++ D+ G+ e++ h---- r+++.

</comment><comment><USER8> Remind me of [http://www.innergeek.us/geek- test.html](http://www.innergeek.us/geek-test.html)

<comment><USER9> 45.75646% - Super Geek. Geez, that took a long time to complete...

</comment></comment><comment><USER10> Funny, I thought the geek code was "RTFM"

</comment><comment><USER11> I would like to write my geek code. Is there a nice Q&A-tool for that?

<comment><USER12> You just read the page and write it out. That's all there is to it.

</comment></comment><comment><USER13> Check out the "Appearance" section [http://www.geekcode.com/geek.html#appearance](http://www.geekcode.com/geek.html#appearance) for a big helping of "only males can be geeks" assumption-making.

<comment><USER14> Check out the "Sex" section [http://www.geekcode.com/geek.html#sex](http://www.geekcode.com/geek.html#sex) for a big helping of not making any gender assumptions

<comment><USER13> Good catch. Its interesting that the gender-neutrality comes only in the "Sex" and "Relationships" sections, and that the only female "I am <famous person>" comes in "Sex" for "I am Madonna."

</comment></comment></comment><comment><USER15> G-

<comment><USER16> G+∴G-

</comment></comment><comment><USER17> Would be nice to update it into a more workable form for today.

<comment><USER18> Maybe key value pairs in json?</comment></comment>


How to estimate minimum memory required for forward pass in a CNN? - <AUTHOR> Assuming I've a MxN input image, I need to estimate minimum memory required for inference. I'm ok with any kind of reordering of computations. <comment><AUTHOR> Basically I need to understand if there is dependency to store multiple feature maps at any point in the forward pass?</comment>


Ask HN: Why can I not post on my regular account? - <AUTHOR>

Im new to HN, but for some reason I can't post with my regular account. The posts just sit in a queue. I can post comments but not submissions.  Did I do something to get banned? My account has around 20 karma. Ive searched, sent email to info, but can't find the answer <comment><USER2> Sounds like you got banned. What was the old account name?</comment>


Seattle makes history with electric garbage truck - <AUTHOR> https://arstechnica.com/cars/2019/05/seattle-makes-history-with-electric-garbage-truck/ <comment><USER2> Hydraulic hybrid is much better for this application. Cheaper, and captures much more of the braking energy.

[https://www.hydraulicspneumatics.com/waste- management/ohio-t...](https://www.hydraulicspneumatics.com/waste- management/ohio-town-welcomes-first-hydraulic-hybrid-garbage-trucks)

</comment><comment><USER3> 56miles, and 600 stops.

The latter sounds like the limiting factor, where I live the garbage truck stops at every house on the block, which very quickly adds up.

The question that seems to remain unanswered in the article is whether the truck fits into the existing working patterns or will require a second truck charging while the crew is utilizing the first.

<comment><USER4> I think so too. A garbage truck when loading is likely only making 5mph if that. 56 miles then is ~10 hours. Thing that would eat miles is the distance between the service area and the transfer station.</comment></comment>


Launch HN: Dyneti (YC W19) – Helping apps stop fraud and process payments faster - julia-zheng Hi HN,
We're Julia and Lena, the founders of Dyneti (https://dyneti.com). Our first product is DyScan, an SDK that helps apps stop fraud and process payments faster by taking a picture of a credit card (https://youtu.be/3gzDECAsqXs).
We met about 3 years ago at Uber, where we worked together to fight fraud on the platform. (Merchants are liable for fraud losses on digital transactions). One thing we noticed is a problem industry-wide is that while there is tons of investment in detection (rules and models and features), barely any work goes into figuring out what to do to someone after tagging them as fraudulent. Most of the reliable actions - the ones that actually stop fraud - are very severe (e.g., account banning). In order to minimize good users impacted, fraud systems are built to detect very specific fraud behaviors. It is therefore easy for fraudsters to reverse engineer models and rules and iterate around them, which means even more investment into detection.
Along those lines, we noticed few companies realize card scanning is a powerful tool to reduce fraud and improve digital transaction security. Stolen credit card fraud is a major contributor to payment fraud losses. Fraudsters attempting to pay with stolen cards rarely have the physical card on hand, but rather, are running through a list of stolen credit card numbers, expiration dates, and cvvs. Having people enter payment information through a card scan will only allow users with a physical card present to go through with payment. It's extremely rare to have a tool that both improves customer experience and improves security - but an accurate card scanner accomplishes this.
In addition to being a powerful tool for fraud prevention, DyScan also provides a nontrivial conversion boost at checkout by reducing time and effort required to enter payment information (under 5 seconds for DyScan, compared to 21 seconds for manual entry). DyScan is also the only card scanner SDK that works on all credit card formats, including non-embossed numbers, numbers on the back, vertical cards, and Quick-Read format cards (those are the weird ones you may have seen around with a four-digit groups stacked on top of each other). Card.io, which is the card scanner experience you may have seen in other apps, works on only one credit card format (embossed numbers on the front of the card).
Other card scanners aren't great because they were constrained technologically at the time they were built. Due to PCI compliance, credit cards must be scanned on device, and it hasn't been possible to get a good deep learning model small enough to do this until very recently (due to more neural net processing power on devices and better tooling). The additional benefit of this approach is that it means zero latency, which can make a huge difference in terms of user experience and user friction.
How it works: After an app integrates DyScan into its checkout process, their users can enter payment information by holding a credit card up to a smartphone camera. At the same time, DyScan verifies that the card is real and non-fraudulent. This results in more good transactions while bad transactions are blocked.
We've been working hard on DyScan for the past few months and are very excited to share it with the HN community and get your insights on what we're building.
Thanks for reading!
Julia & Lena <comment><AUTHOR> I'm glad someone made tech that can scan my card with the numbers on the back, thanks! Hopefully all the vendors I use start using your product. I'll also be looking into it for my own product!

Regarding your fraud models, I actually used to work in this area (I'm pretty sure we know a lot of the same folks at Uber!) and I'm curious where you're getting your fraud model data from? Do you have partners you're working with? Until you have enough transaction volume, how will you train your models?

<comment> julia-zheng Cool!! Until we have enough transaction volume, we are replicating methods fraudsters use to create fake cards to train our models.

</comment></comment><comment><USER2> Not to make it sound simple, but all you're doing is running a small neural net on device to identify multiple card formats. What prevents a payment gateway like stripe to do the same thing inhouse? Doesn't sound like a very difficult thing, especially considering that tools to do on device ML have proliferated.

<comment><USER3> Lena here: Certainly, other people can do it, but it would be quite an investment for them. Here are some reasons why:

• The on-device tools are still in their infancy, and so it was actually a lot of work for us just to figure out what configuration of framework would work in a production system. For example, we can't use coreml for our iOS framework since it is only supported on iOS 11+ and many apps still support iOS 9+.

• There's very strict model size and performance constraints that require us to really optimize our model. App binary sizes are often tightly controlled in mobile first companies so we don't have much wiggle room in terms of how large our network can be. On top of that, we want the model to run reliably and quickly on phones from 5 years ago (which are still used today), when the hardware was much worse than it is today.

• Getting the training data for the model isn't easy.

• The model needs to be maintained, so any company that tries to do this would need to have a dedicated team on it. Credit card providers are constantly changing the style of cards they make (for example the new Visa Quickread format), and the framework has to be updated to keep up with this.

<comment><USER2> If it's not revealing too much, can you tell us a bit more about how you got the necessary training data? And any tips on optimizing models for on-device ML?

<comment><USER3> Sorry, I unfortunately can't reveal too much about the training data. As for tips on optimizing models for device, choosing a fully convolutional architecture is almost a requirement as any substantial fully connected layer is going to take up too much space. For convolutional layers you want to use more efficient versions like depthwise separable convolutions. Using quantization is a pretty easy way to reduce the size of the model without sacrificing too much performance as well.

</comment></comment></comment></comment><comment><USER4> Congrats on launching!

What happens to the photos of the cards?

Where is your privacy policy? I took a look at the site and didn't see one. They're required by CA law.

<comment> julia-zheng Thank you!

The photos of cards aren't stored anywhere - everything is analyzed on device to ensure privacy and compliance.

Re privacy policy - thanks, gotta put that up!

<comment><USER5> Does this mean the app is necessarily a trusted component here? What's to stop an adversary from reverse engineering the application, especially on a platform like Android where applications are side-loaded and binaries largely maintain source-level semantics?

I guess you could argue that, from the merchant's perspective, they just want to avoid being the easiest target.

<comment> julia-zheng Exactly - the effort required for this much beyond what most fraudsters would be willing to do on most platforms.

</comment></comment></comment></comment><comment><USER6> Sounds like it may be trivial for you all to make another app that does the same thing with IDs / identification..

I like the on-device privacy with your system. I could have used an ID check / age check thing like this a few times over the years. Some people have been good at taking a photo of their ID and emailing it or posting to a web form, others tried taking the top results on google for fake ID and using a picture of that...

I would not expect a system like this to detect 100%, but it could have easily cut in half the amount of terribly fake IDs that were sent in to us.. which sounds nice.

Might be an option for whichever company to add in a user select-able option to upload / send the pic in for human review (and further net training) as an option if it fails, or fails with a certain percent or something..

can see a lot of use cases for this, glad to see you all working on this.

<comment> julia-zheng Amazing - thanks for all the feedback. This is definitely on the roadmap - stay tuned!!

<comment><USER7> Danger on that front...

A company I worked with in the not so distant past got some real nastygrams.

There's a mountain of patents in that space that are near impossible to avoid stepping on.

<comment><USER6> Thank you much for sharing this. That's something I would not have even thought about.

On the flip side of that thinking, I wonder if that could be used to put all the places out of business that are trying to make the UK's 'you must prove age to see porn or nipples law' work, and if that would invalidate their law or just make it convenient that it could be impossible to implement and therefor just a backdoor to ban porn.

</comment></comment></comment></comment><comment><USER8> I use physical cards very rarely. I prefer to use ApplePay wherever possible.

Where that isn't possible, I prefer to use virtual cards that are created for me by my bank or by a service like privacy.com. They are single-merchant cards, so once they are used, they can't be used with any other merchant. And I can put spending limits on them, and cancel them at any time.

With respect, I don't trust your scanning mechanisms, nor do I trust the vendors (your customers) that would be permanently storing my credit card data.

So, what do you do regarding detecting credit card fraud for people using ApplePay or other legitimate virtual card providers?

<comment> julia-zheng Interesting - we're currently only detect credit card fraud for the segment of customers transacting with more typical credit cards (the largest chunk of the market) but this is good to know.

</comment></comment><comment><USER9> very awesome tech + privacy combo

Since fraud detection is done on-device, is there any clever encryption or security features that stop me from issuing a direct API request to the service with my (or someone else's) credit card info? If not, I'm worried that a technical fraudster could script their way around the ML model (and therefore not need the physical card), especially since cc lists are already nicely formatted. This would hurt pretty badly if the service assumes that DyScan is infallible and then doesn't have mechanisms for detecting fraud post-signup.

<comment> julia-zheng Great question! The company that owns the app is ultimately responsible for the encryption there, but there are a few ways we can help out with that as well (sorry, I know this is a terrible answer - but it's best practice not to reveal too much about how the encryption works)

</comment></comment><comment><USER10> This is a pretty good idea. Credential stuffing style CC fraud is a massive industry. Scanning could significantly raise the bar on fraudsters and give them much headache when it becomes widespread. Good luck!

<comment> julia-zheng Thanks!

</comment></comment><comment><USER11> Cool product! You should integrate with the Stripe wherever possible out of the gate. I use Stripe but still accept the CC info directly through their widget. You could really polish that phase for me.

On a side note: It annoys me when I see a page with little info on the homepage, I click "Demo", and I'm presented with a form. Why not at least put your Video on your Demo pages and then use the form for a "Personalized Demo" aka. sales call.

<comment> julia-zheng A stripe integration out of the gate would be REALLY nice :)

Thanks so much for the feedback! Just put it on my to-dos

</comment></comment><comment> throwaway-1283 Good opportunity. It's funny how many apps integrate with Card.io despite how limited it is and the fact that PayPal (which acquired it) open sourced it and stopped maintaining it years ago.

I think a big threat would be if Apple opened up their card scanning tech for adding cards to Apple Wallet as an SDK to developers. Personally I've found that experience to be really awesome and they can scan both embossed and non- embossed cards well.

<comment> julia-zheng Whoa you know a lot about Card.io!

Apple does have great card scanner. Our thoughts on this (would love to hear yours) are they have little incentive to open up the card scanning tech standalone for developers, but even assuming they did, the standalone Apple scanner wouldn't include any fraud prevention features.

Longer term, we plan to leverage data from our customer base to make our fraud prevention features very robust - and we suspect this would be difficult for a competitor to replicate.

</comment></comment><comment><USER12> Hello! Have you tested out semi-transparent cards (N26, ING) or vertical cards?

[https://www.tide.co/blog/a-card-designed-around- you](https://www.tide.co/blog/a-card-designed-around-you)

Bonus weirdness for tide cards: Name, credit card number, signature and cvv are all on the back, haha

Some Bank in Spain gives out vertical cards too, someone I know has one.

<comment><USER12> Also: Are Maestro cards supported? Girocards (EC cards)?

Most Germans have a girocard, way less hava got a debit/credit card.

<comment><USER3> Yup, we haven't seen an issue with semi-transparent cards or maestro cards and have built-in support for the vertical cards as well (though we're still trying to optimize the UI/UX for that so let us know if you have ideas!). We don't support girocard yet, but we're working on adding support for that.

</comment></comment></comment><comment><USER13> How does this flow work for desktop based e-commerce transactions, where a camera is not as easily integrated as mobile?

 _Edit_ : Actually it is quite trivial to request access to the camera via desktop now:

      navigator.mediaDevices.getUserMedia({ video: true })

<comment> julia-zheng Currently it's only available on iOS and Android apps, with mobile web coming soon. We're still working out exactly what the experience will look like on desktop (it's a less natural flow for sure), but once we work out the kinks we'll be building that out as well.

</comment></comment><comment><USER14> How does it know someone is holding an actual credit card and not a fake printed one?

<comment> julia-zheng There's a number of ways that a fake card will look different from a real card - we aggregate these signals and form a decision on real vs fake (sorry, we know that's a terrible answer - we would disclose more, but it's best practice to keep specifics of fraud detection a secret to maintain efficacy). Surprisingly, the gap between real and fake is wide enough that we can with good precision separate those cases. Of course, someone could build a replica indistinguishable from a real card, but at that point you've raise the barrier of committing fraud much higher than simply having a stolen credit card number, so chances are the fraudsters would migrate to some other platform

<comment><USER15> I once saw a presentation from BSI (Germany Cyber Security Agency) where a researcher used computer vision / AR to create a video feed of a realistically looking ID card based on a simple paper copy of the card. They could add reflections and holograms to the paper copy that looked absolutely realistic, and they were able to use it to pass a video-based identification test (Video- Ident) that's widely used by banks in Germany to remotely validate the identity of new customers. The company then had to change their validation method by asking people to not only hold up and tilt the passport (to reveal the holograms) but to also pass their hand in front of it while holding it, which would lead the AR algorithm to fail.

So I'd say it's definitely possible to fool even a person let alone an algorithm, as you said it's questionable though if there aren't any easier ways for criminals to use stolen card numbers.

<comment> julia-zheng Thanks for sharing that - super helpful to know.

Definitely agree it's possible to make good fake cards, but it makes it difficult enough that fraudsters will usually migrate to a different platform. Since banks are probably the most attractive business to fraudsters, we'd suspect banks would have to make life much more difficult for fraudsters than the average business in order to chase them away.

<comment><USER16> I do love the product and don't want to appear like I'm bashing it. Great work on lunching! Best of luck!

However, it seems if this practice (scanning card) becomes more widely adopted and becomes a standard process of detecting fraud, it'd become a relatively easy target for fraudsters to crack, right? I don't know if DL or card making technology will outpace fraudsters' will to make fake cards?

Further more, if I'm a fraudster and know some websites that adopt this policy, there is a big incentive for me to get a credit card embossing kit to start making cards, right? After all, I'd think it is far easier to make a copy of a card than making the magnetic strip thing? And given your tech is a strong signal of 'not fraud', if it is relatively easy to beat this system, wouldn't it attract a huge number of fraudsters?

<comment><USER10> Security is always about bar raising. Any protection can be bypassed. But for a non trivial period, fraudsters would be forced to try their CC listings on other apps, not protected by this tech. This will provide tremendous value to Dyneti's customers.

<comment><USER3> Lena here: completely agree avip. In terms of fraud losses, most companies are really worried about fraudsters that can scale their operations, not super targeted attacks. If you can increase the cost (in terms of time and money) of committing fraud, it becomes less scalable and less profitable for the fraudster. So certainly, a fraudster can get a card embossing kit and start making cards, but this is going to be much slower. Without our solution fraudsters are just typing in a card number, which takes seconds! Unless each instance of fraud is highly valuable (for example, as is the case with banks as Julia mentioned earlier), the economics start to look worse and worse. On top of that (and this certainly applies more to any deep-learning based solutions trying to bypass us) our models will constantly improve and so we'll force the fraudsters to constantly improve any fake card generation, making the fraudsters spend time on that rather than defrauding.

<comment><USER16> Hi Lena, Great answer! Congrats on launching. I do have a few more counterpoints.

Thinking about this from a individual fraudster perspective. Acquiring a stolen cc is not an easy transaction, there is risk, and cost involved. So I think each fraudster would be trying to maximize the value of each stolen cc they have on hand. When you have a system that doesn't tell the fraudster what is causing the stolen cc to be rejected, the fraudster has nothing but trial&error to improve their chance, maybe instead of public wifi they have to use a private one, maybe instead of a gmail account they have to use a edu account. But in this case, if they know that a embossing kit will significantly improve their chance, wouldn't they spend the money and get that technology?

The bottom line is this technology has to make it more expensive for the fraudster to throw their hands up and say "well i better go try a different place". but I'm not sure if the barrier is high enough here. Furthermore, if you have an 'invisible' barrier, then it is all about trial and error, if you have a 'visible' barrier, I think it is just going to garner more attention and more people trying to solve it?

<comment> julia-zheng So actually acquiring stolen cc numbers is very easy - there's a bunch of marketplaces that sell thousands of them. Figuring out a scalable way to extract value out of them, however, is hard. More than visible or invisible barriers, what makes a fraudster want to spend time getting around the defenses of a specific business is the value of the offering (e.g., banks vs an app that sells a service)

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER17> This is inspiring! For a new grad going to a unicorn, what would you recommend as far as types of teams that would teach me skills that help me build my own startup?

<comment> julia-zheng Definitely take the below with a grain of salt - this worked for me thus far but there are probably paths other people have taken that worked equally well or better :) My recommendation would be: 1) A smaller/less established team where you'll be responsible for building out key chunks of the team 2) A team where you can build expertise in a domain you find interesting, and where you think there might be more problems than solutions

The benefit of working on a smaller/less established team is getting the autonomy to build something that's immediately impactful to the company and its customers, while not having to worry too about how to stay alive (fundraising, revenue, resources) - I think that's pretty good training for building a startup.

Picking a team where you'll get expertise in a newer/growing field can be helpful too - think something where you'll only need a few years to become an expert and start adding value. Also be sure to pick something you like, since if you do start a company in that field, you'll likely be spending a big chunk of your life on it.

<comment><USER17> Thanks so much for the reply! I'll use this as I go forward to hopefully make the right decisions. I wish you the best of luck with your venture, it's an amazing idea and I believe in you both :)

<comment> julia-zheng Hope it helps - good luck!!!

</comment></comment></comment></comment><comment><USER18> What happens if a user's card can't be scanned? For instance, bad lighting conditions, or an unusual card format?

<comment> julia-zheng Great question! The small proportion of cards that can't be scanned can be pushed through a higher friction fraud prevention flow. Since card scanning is low friction, this allows you to catch a ton of fraud at minimal impact to good users, and subject only a very small number to the higher friction flow.

</comment></comment><comment><USER19> Congratulations! Been looking for EXACTLY this for our app.

<comment> julia-zheng Thanks! Just sent you an email :)

</comment></comment><comment><USER20> Are those real cards in the video!? Cool product btw.

<comment> julia-zheng Hahahaha they're all cancelled or expired cards :)

</comment></comment><comment><USER21> i like the idea, but what happen with the web sites or your produc only works for moviles?.

<comment><USER3> Currently it's only available on iOS and Android apps, with mobile web coming soon. We're still working out exactly what the experience will look like on desktop (it's a less natural flow for sure), but once we work out the kinks we'll be building that out as well.

</comment></comment><comment><USER22> Very cool idea and well executed.

<comment> julia-zheng Thanks!</comment></comment>


The 32 startups that will present at Start-Up Chile Demo Day - <AUTHOR> http://www.slideshare.net/startupchile/ill-be-on-stage-on-the-demo-day

<comment><USER2> for people (like me!) who didn't know, this is happening may 23 at the GAM (the place on alameda that burnt down a while back (central santiago)) and will be streamed live - <http://www.demodaychile.com/eng.html>

is it possible to sign up to attend? the sign-up link isn't working. is it not yet open?

<comment><USER3> The link is broken on the English version. If you go to <http://www.demodaychile.com/> click on "Inscríbete para participar" (register to participate).

</comment></comment><comment><USER4> I think there might be a lot of things that we at LATAM need to learn BUT, you guys are feeding a monster of tech developing. We are just, NOT WELL CONNECTED and we don't know the right people, but we are capable of making amazing and astonishing inventions. So be patience and keep the high value critics, cause we will never give up until we move to perfection.

</comment><comment><USER5> Isn't it a bit premature to put your cards on the table and specify what kind of money you're looking for?

<comment><USER6> I'm wondering why so many of them are looking for $200K or less. $200K is more of a friends and family sized round- it's very rarely enough to get a startup to Series A or profitability.

It seems like saying you're raising a small amount sends a negative signal that you're not interested in building a big company to investors.

<comment><USER7> Yeah, it is a tricky subject because if you are raising money down here you have to adapt to the local environment. There is definitely not as much money flowing around and the "normal" seed rounds are more in the 100k to 750k range which is a lot less than what it is in the USA. Down here, investors are more risk averse and less "smart" so they are more comfortable with smaller investment steps, especially in the early stages.

In addition, like @mtr mentioned, the money goes much further down here. The cost of living is around 4 times cheaper and the cost of hiring developers is getting close to 3 times cheaper and there is a lot less competition for talent. The good thing is that they have the same amazing climate as Cali down in Chile ;)

That said, you are definitely right about the signal it sends. I guess the pitch and the fundraising campaign has to be country sensitive in order to be more effective.

</comment></comment></comment><comment><USER8> Im all for startup Chile succeeding, but quite a few of these companies are merely concepts with webpages..this wouldnt fly in the US...even at some bschool pitch competitions. The startup Chile folks, while their heart is in the right place, have some work to do- before you can publicize a startup incubator globally, you might want to learn proper english.

<comment><USER9> This Demo Day was only open for startups looking for investment. There are other startups here with operational websites and revenue but who simply didn't bother with this.

</comment></comment><comment><USER10> Regalii seems to be using the GovWorks (now defunct) logo.

[http://www.businesspundit.com/25-internet-startups-that- bomb...](http://www.businesspundit.com/25-internet-startups-that-bombed- miserably/) <http://en.wikipedia.org/wiki/GovWorks>

<comment><USER11> They are different enough in my opinion

</comment></comment><comment><USER12> This is gonna be HUGE and is exactly what the fledgling start-up community in Santiago needs! Great job guys!

</comment><comment><USER13> Excellent! I've been looking for a good cat-picture website. (j/k)

Very interesting variety of start-ups.

</comment><comment><USER14> To be clear there are other startups in this round that aren't demoing/raising cash...

</comment><comment><USER15> Thats cool thats in Chile , Amazing whats going on there +1</comment>


Ask HN: Why does AirBnb need 800+ employees? - <AUTHOR>

It seems like they hired incredibly fast. Their LinkedIn page shows 800+ employees. <comment><USER2> I hear these types of questions about many web companies from time to time in that the assumptions is you just need a small bundle of folks to run the website but in reality when a business gains traction the website is just the tip of the iceberg in many cases. The number of employees needed can snowball as the business starts to take off... legal teams, finance, accounting, QA, HR, BAs, management, ops, etc - it all adds up to usually more than one would assume. Additionally the customer facing product can be a very small part of the overall tech solution in that developing needed internal tools and systems can require large numbers of employees.

Typically your biggest numbers are going to come from sales folks / account managers in that, as an example, if the business model allows for a sales rep to sustainably bring in 200k on an 100k salary you most likely are going to hire as many as you can get. Groupon is a good example of this in action although it obviously has not been as successful as they would like.

</comment><comment><USER3> Because once you get big enough it makes sense to have specialists working on small parts of the business. Those specialists all should be creating more value than their cost.

Just think about the credit card side of the business. \- They should have one person who's whole job is to make sure their interchange charges are as low as possible. \- They likely have a lot of float, money from where customers have paid for stays upfront that they hold onto until the housing providers get paid. If a billion dollars flow through their hands a year and they pay 15 days after the recieve the money, there is $41 million in float that someone needs to invest for the short term. \- An entire team of people likely has to deal with credit card fraud.

Any webish company past a revenue range is going to have these issues to deal with.

</comment><comment><USER4> First of all I _don't_ think AirBnB currently has too many employees & when they were 85 employees they were adding 2-3 employees per day[1] Likewise their team has also grown due to a couple of acquisitions/acquihires – Crashpadder, Accoleo and DailyBooth.

The reason why AirBnB needs a team of 800+ employees is because, they're trying to expand as quickly as possible into as many countries as they can – leveraging the growth they already have there. For example they have 20,000 properties listed in Asia[2] & are focusing heavily on increasing this number & have just opened offices over there.

The [2] post also highlights some of the reason for the number of employees as each location requires, "a team of dedicated local customer support agents and a hotline for queries" due to AirBnB offering 24/7 support to its users. As well as having, local customer support agents who help the company provide 24/7, AirBnB also requires: Management, Finance, Accounting, Legal (Recently they hired David Hantman from Yahoo[3] to help tackle some of their regulatory issues), Human Resources, Business Development, Customer Support, Other Operational Staff etc alongside their developers to build out the company & leverage the market opportunity.

[1] [http://thenextweb.com/apps/2011/05/25/airbnb-is-growing- fast...](http://thenextweb.com/apps/2011/05/25/airbnb-is-growing-fast- adding-1000-listings-every-day/)

[2] [http://thenextweb.com/asia/2012/11/21/airbnb- targets-2-milli...](http://thenextweb.com/asia/2012/11/21/airbnb- targets-2-million-properties-in-asia-as-it-begins-introducing-local-customer- support/)

[3] [http://allthingsd.com/20121015/yahoo-loses-government- relati...](http://allthingsd.com/20121015/yahoo-loses-government-relations- head-to-airbnb-internal-memo-time/)

</comment><comment><USER5> they dont really need 800 employees. they just dont know which of the 80% of employees are the productive ones. They could cut 20% with ease but it's really hard to determine who isn't needed. As business scales it gets really tough to figure out who is needed and isn't. All growing companies face this. Companies should focus on being leaner.

</comment><comment><USER6> In addition to what others have mentioned, something that came to my mind is that they're also big enough to have people lobbying for legislation against them in multiple places. That's going to require extra people if for nothing else but to be liaisons to the lawyers and anti-lobbyists.

</comment><comment><USER7> Worldwide representatives/salespersons in each country where they have a presence? E.g. [http://www.gizmodo.com.au/2012/11/airbnb-officially-lands- in...](http://www.gizmodo.com.au/2012/11/airbnb-officially-lands-in- australia/)

<comment><USER8> Might be contractors/Part-time ?. if not Obesity will kill them</comment></comment>


How We Determine Product Success - <AUTHOR> http://techblog.netflix.com/2011/01/how-we-determine-product-success.html <comment><USER2> Awesome article. Goes to show that Netflix is one of the best executing companies out there, at the level of Facebook or Google. See also this slideshow: <http://www.slideshare.net/reed2001/culture-1798664></comment>


Computer security: Browser wars are back - <AUTHOR> http://www.economist.com/displayStory.cfm?story_id=13395407 <comment><USER2> "Hackers agree the toughest nut to crack is Firefox running on Windows."

Is this generally agreed by those of you who post on Hacker News?</comment>


Xiki: Can your shell console do this? - <AUTHOR> https://www.youtube.com/watch?v=bUR_eUVcABg

<comment><USER2> I love shells because you can't use your mouse. Nice idea, but it doesn't suit me.

</comment><comment><USER3> What if xiki had been written in emacs?</comment>


Riemann hypothesis proof by Michael Atiyah - <AUTHOR> https://www.youtube.com/watch?time_continue=7&v=jXugkzFW5qY <comment><AUTHOR> Sketch in writing: [https://aperiodical.com/wp- content/uploads/2018/09/2018-The_...](https://aperiodical.com/wp- content/uploads/2018/09/2018-The_Riemann_Hypothesis.pdf)</comment>


Turing's Enduring Importance - <AUTHOR> http://www.technologyreview.com/computing/39669/?fb_ref=article <comment><USER2> Spectacularly accessible article, going from Hilbert to Goedel to Turing to von Neumann. And nice to see that Simson Garfinkel wrote it.

This is exactly the sort of thing that can explain the beauty of computer science and discrete mathematics to people who think that just means "programming". It's __so much more __.

</comment><comment><USER3> Gotta love the random "and so we have computer viruses" paragraph toward the end.</comment>


Is there any way to get faster at solving bugs? - <AUTHOR> http://programmers.stackexchange.com/questions/197675/is-there-any-way-to-get-faster-at-solving-bugs-ive-just-had-a-warning-from-my <comment><USER2> There's some interesting discussion here at the previous (now dead) post of this article:

[https://news.ycombinator.com/item?id=6308316](https://news.ycombinator.com/item?id=6308316)

In particular, this comment about using the scientific method to diagnose bugs is valuable:

[https://news.ycombinator.com/item?id=6308826](https://news.ycombinator.com/item?id=6308826)

It's much more productive to formulate hypotheses and then gather evidence to prove/disprove them than to jump in with the debugger and start trying things at random. It's also worthwhile to spend some time trying to isolate the simplest possible reproduction of the bug.

There are actually books that have been written about how to debug in a systematic way (sorry, I don't remember the titles offhand).

<comment><AUTHOR> > There's some interesting discussion here at the previous (now dead) post of > this article

Looks like someone revived it.

</comment></comment><comment><AUTHOR> The last update on his question is the most poignant. After seeking help online, and failing to improve to his manager's standards, he lost his job. But, he used his stackoverflow account and this question will now appear when someone searches for his username, and may count against him when applying for another job, for which he may be better suited.

</comment><comment><USER3> I blame this on the manager as much as the developer.

A company I've worked for once had a developer quit very abruptly. He did so immaturely, but it happened because his manager was dissatisfied with his performance and instead of offering tips and advice early on when the problem was first observed the manager waited until about eight months had passed and unleashed incredibly harsh criticism on him, basically threatening to fire him without mercy if he didn't improve. The developer felt so bad and embarrassed that he couldn't stand to work there and he just quit without even giving two weeks' notice. I think he was completely caught off guard and went from feeling great in the job to feeling like complete shit.

He was allowed for eight months to believe he was doing well, then told that all that work was not appreciated and he'd be fired if he didn't more or less immediately do better.

<comment><USER4> Well, there's also "I've been here 2 years and it's obvious to everyone that I'm still struggling" and "I think I've become so demoralised and feel so marginalised that I've lost a lot of the fire..."

So this dev knows he's been struggling and he knows everyone around him knows it. There's no indication at all that this was a surprise to him or that the problems hadn't been mentioned earlier. It sounds to me that the manager gave him much more time than was really deserved to catch on, and he simply never did. We're both guessing a bit based on incomplete info, but it looks like the message didn't go from "you're doing great" to "you're doing horribly", but rather went from "you're struggling but we're willing to give you time" to "you know, time is almost up".

If after two years it's obvious to everyone that you're the weak link, then while training might help a little, you're probably just in the wrong place.</comment></comment>


Meet the bughunters: the hackers in India protecting your data - <AUTHOR> http://www.theguardian.com/world/2016/apr/02/meet-the-bughunters-the-hackers-in-india-protecting-your-facebook-profile <comment><USER2> I think guardian didn't do their homework right. Apparently Rahul tyagi just like Ankit fadia is considered to be a con-artist.

[https://news.ycombinator.com/item?id=4316574](https://news.ycombinator.com/item?id=4316574)

</comment><comment><USER3>
        > rupee millionaire

I don't wish to put down Mr Prakash's achievements, but is that actually a celebrated figure in India - or at ~£10.6k is the word 'millionaire' just a sensationalism for our benefit?

<comment><USER4> ~£10.6k is an OK figure in India, but depends where you are and what you do.

In an international company, doing UAT type testing and investigation, it would be about average for an assistant manager, but the variance is vast, even between people sitting next to each other.

If that figure is per month, then he's really doing well, pulling in the same as an SVP in an international company managing a team doing a similar role.

<comment><USER3> Right, he's doing well but it seems odd to say to a predominantly British audience that he's a "multi-millionaire [in rupees]", when actually the implication of that is 'hugely successful, doesn't need to work', rather than 'successfully self-employed/running his own business'.

Congratulations and all the best to him, of course, I just think it's a misleadingly sensationalised subtitle.

</comment></comment></comment><comment><USER5> Amazing that all publicly traded companies are not by law required to have bug bounties.

Same goes for any major open source project too.

<comment><USER6> Nobody should have to offer bounties. Researchers should not expect to get paid for their unsolicited work.

We probably agree that vulnerability reports should be seen as a positive thing. What software owners should have are policies and procedures for transparently handling vulnerability disclosures. At most, I think having some flexible process should be required as part of a certification (PCI, etc).

I do think that knowledge of a vulnerability and lack of action to fix it in a reasonable amount of time, which results in a breach should be treated more seriously. At the same time, encouraging reports of breaches is hard as it is and introducing more punishment would make everyone want to just keep quiet or as ambiguous as possible. I'm not sure what a good solution to this would be.

<comment><USER7> > Nobody should have to offer bounties. Researchers should not expect to get > paid for their unsolicited work.

The Chinese and Russian exploit markets don't seem to care if the work was solicited or not.</comment></comment></comment>


Habit Labs Creates Games to Make You Live Healthier - <AUTHOR> http://launch.is/blog/bringing-quantified-self-to-the-masses-habit-labs-creates-ga.html

<comment><USER2> Yet another incredible Startup to come out of Seattle! It's people like Jen and Buster that make me proud to say "I'm part of the Seattle startup scene!"

</comment><comment><USER3> Big fan of Health Month - can't wait to use Budge.

</comment><comment><USER4> Mos' def one to watch. Bud.ge is going to be fun to see.</comment>


Ask HN: How to Shrink Bootdisk on GCP? - <AUTHOR> Found this tutorial: https://donovancraig.com.au/blog/2019/11/22/shrinking-gcp-drives/<p>But it's not working, I am getting errors when I start weresync daemon. <comment><USER2> Maybe do not use HN as a stackoverflow forum.</comment>


A Mathematical Theory of Communication (1948) [pdf] - <AUTHOR> http://people.math.harvard.edu/~ctm/home/text/others/shannon/entropy/entropy.pdf <comment><USER2> Probably one of the dozen or so most important publications of the twentieth century. Ironically though it would be Norbert Wiener's interpretation of information (exactly Shannon's times minus one) that would cement itself in the popular lexicon due to it being far more intuitive. Where Wiener posits information as negative-entropy (or "order"), Shannon interprets it as representing a degree of freedom, or uncertainty. The problem with Wiener's is that the underlying epistemology carries a subjective bent, where information is equivocal to "meaning" or semantic content. Shannon's, meanwhile is ultimately superior as an objective metric, though far less intuitive (under his interpretation, a random string is technically the most information- saturated construct possible, because it possesses the highest degrees of freedom).

<comment><USER3> To say Wiener and Shannon founded information theory is like saying Lorenz and Einstein founded speial relativity. I don't think physicists would consider Lorenz having made a major advance, and in fact even after the relativity was explained some people still didn't understand it.

Wiener made important contributions to mathematics but not to information theory. He wrote a book saying that entropy is related to "information" and is maximized for a Gaussian. That's about his involvement. The paper attached goes way beyond that.

<comment><USER2> I didn't claim Wiener founded it, only that his popularization of the term is more ubiquitous than Shannon's formulation.

</comment></comment></comment><comment><USER4> What I think is telling, is how easy to read Shannon's paper is. Even today it is used pretty much as is at many EE colleges to teach communication theory.

Another cool fact: Shannon's master thesis is most likely the most influential one of all time: in it, he linked Boolean algebra to electrical circuits with switches, essentially inventing digital circuit theory.

<comment><USER5> The master thesis: [https://dspace.mit.edu/handle/1721.1/11173](https://dspace.mit.edu/handle/1721.1/11173)

<comment><USER6> Wasn't the idea first pointed out by C. S. Peirce back in the 1880s?

</comment></comment></comment><comment><USER7> BTW here's the paper by Hartley cited on the first page it is also very readable and insightful. I found it helped clarify some of the subtler points in Shannon's paper to read it as well.

[http://keszei.chem.elte.hu/entropia/Hartley1928text.pdf](http://keszei.chem.elte.hu/entropia/Hartley1928text.pdf)

</comment><comment><USER8> Recommended on an earlier thread: From Aristotle to John Searle and Back Again: Formal Causes, Teleology, and Computation in Nature" by E. Feser.

[https://muse.jhu.edu/article/618359](https://muse.jhu.edu/article/618359)

[http://www.netherhallhouse.org.uk/wp- content/uploads/2018/03...](http://www.netherhallhouse.org.uk/wp- content/uploads/2018/03/formal_causes.pdf)

Source: [https://news.ycombinator.com/item?id=12080670](https://news.ycombinator.com/item?id=12080670)

</comment><comment><USER9> If you're interested in this, check out Cover's Information Theory textbook — the rabbit hole goes much deeper. One of the most interesting examples, is that when you're betting on a random event, Shannon entropy tells you how much to bet & how quickly you can compound your wealth. Cover covers (heh) this, and the original paper is Kelly: [http://www.herrold.com/brokerage/kelly.pdf](http://www.herrold.com/brokerage/kelly.pdf)

<comment><USER10> Kelly's paper (based on this paper by Shannon), is responsible for fundamentally reshaping equity, commodity and even sports betting markets.

I highly recommend William Poundstone's book, "Fortune's Formula" as a biography of those ideas - it's almost as good as any Michael Lewis book on the subject would be.

</comment></comment><comment><USER11> The article was renamed "The Mathematical Theory of Communication" in the 1949 book of the same name, a small but significant title change after realizing the generality of this work.

<comment><USER8> What was the original title?

<comment><USER11> __A __Mathematical Theory of Communication

<comment><USER8> So "A" was changed to "The"?

<comment><USER12> Exactly.

</comment></comment></comment></comment></comment><comment><USER13> I just recently finished the biography of Shannon called "A Mind at Play."

It was quite a joy and I highly recommend to anyone interested in these sorts of bios.

<comment><USER14> Concur. That is a good read.

</comment></comment><comment><USER14> > The fundamental problem of communication is that of reproducing at one point > either exactly or approximately a message selected at another point. > Frequently the messages have _meaning_ ...

I never fail to suppress a chuckle when I read that.

<comment><USER15> The crucial point is the word "selected". As in "selected from a pre-agreed set of possible messages".

</comment></comment><comment><USER8> A well-deserved perennial. Some prior discussions:

2016, 53 comments: [https://news.ycombinator.com/item?id=12079826](https://news.ycombinator.com/item?id=12079826)

2017, 11 comments: [https://news.ycombinator.com/item?id=15095393](https://news.ycombinator.com/item?id=15095393)

</comment><comment><USER16> There seems to be a great, unresolved difference of opinion about whether information entropy and thermodynamic entropy are commensurable.

In trying to connect Shannon entropy to thermodynamic entropy, I always get stuck on the fact that you need to have a defined alphabet or symbol set.

<comment><USER17> vs an arbitrary defined number of dimensions?

Their are more exotic mechanisms to define entropy: [https://en.wikipedia.org/wiki/Parastatistics](https://en.wikipedia.org/wiki/Parastatistics)

<comment><USER16> In a thermodynamic sense, information input (say, of photons) is generally going to increase the entropy of a receiving system. Only certain kinds of information can reduce the entropy of the receiving system. Too much information (i.e., too many photons) can literally burn your eyes.

I don't see how to square those manifest physical effects with the immateriality of Shannon information entropy.

<comment><USER17> Is this not the problem of Maxwell's Daemon, if an intelligent agent observes and interferes with a particle system to reduce the system's entropy then overall entropy is still increasing because the agents needs to store and calculate information in some physical medium, be it brain matter of silicon.

<comment><USER16> Not exactly, I don't think.

In the Shannon formulation, there isn't a notion of "too much information" \-- it is all symbols.

But in reality, too many photons can burn our eyes or a denial of service attack can break a website. Too much information is a reality --because we are thermodynamic entities.

I don't see how to understand that with Shannon.

<comment><USER17> Yeah right, and too much heat can burn my toast, forget about global warming it about universal warming, I don't understand that with Einstein either.

</comment></comment></comment></comment></comment></comment><comment><USER18> Shannon's work has had vast influence.

Here is a great, short overview of the topic => [https://youtu.be/_PG- jJKB_do](https://youtu.be/_PG-jJKB_do)

There is no entropy regarding question of whether the Jade is an attractive presenter.

<comment><USER19> > There is no entropy regarding question of whether the Jade is an attractive > presenter.

Please don't do this here. It just comes across as super-crass.

<comment><USER18> Ack

</comment></comment></comment><comment><USER20> I think this gets posted on Hacker News once or twice a year. It's a pleasure every time.

</comment><comment><USER21> Anyone have good recommendations on LDPC or Turbo Code theory?

<comment><USER14> David MacKay did some good stuff, and source code is available: [http://www.inference.org.uk/mackay/CodesFiles.html](http://www.inference.org.uk/mackay/CodesFiles.html)

I find MacKay's explanations very clear. Sadly, he passed away far too young.</comment></comment>