Darpa begins work on 100Gbps wireless tech with 120-mile range - <AUTHOR> http://www.extremetech.com/computing/143455-darpa-begins-work-on-100gbps-wireless-tech-with-120-mile-range?utm_source=rss&utm_medium=rss&utm_campaign=darpa-begins-work-on-100gbps-wireless-tech-with-120-mile-range <comment><USER2> The thing to remember with all geosynchronous satellite communication is latency. It's terrible. By virtue of being 36,000 km away, you fundamentally can't have a communication time of less than 1/4s. That's fine for moving large numbers of bits (video transfer) but terrible for 2 way communication. Without any other delays, it takes over 1/2 a second between sending a request and seeing the result.

Perhaps the protocols they're developing will have use for ground level civilian communications, but it's unlikely that satellite based internet will ever see widespread adoption in the west because of latency.

<comment><USER3> But why should the satellites be on geosynchronous orbit? What if we bring them closer to Earth? For example, when we use mobile internet, we travel from antenna to antenna. With satellites on lower orbits, the antennas will travel around us.

<comment><USER2> This is possible, but the problem is that the closer your satellites get to earth, the larger number of satellites you need in your constellation to maintain coverage. Iridium[1] spent $6 billion putting a very large constellation of satellites into orbit and promptly went bust. Convincing an investor that you won't end up having the same problems that iridium had would be tricky.

It's certainly not impossible, but I would be surprised if the economics of satellite based internet can compete with fibre based networks. The areas where fibre isn't feasible are also probably the areas with few people, and so the potential to make money is limited.

Iridium has shown that (once you disregard capital costs), there is a niche for satellite based telecom services, but it's a fairly niche area.

[1]: <http://en.wikipedia.org/wiki/Iridium_Communications_Inc>.

<comment><USER3> Well, if it's DARPA, then probably the main purpose of the network will be military. And I'm pretty sure that they have much more money than Iridium.

<comment><USER2> Obviously military use is quite different from civilian use. I was really trying to address the part of the original article which suggested that this technology might make its way into civil life.

</comment></comment></comment></comment></comment><comment><USER4> is it just me, or do other people get bored by "begins work on" titles too?

first of all there's probably more than darpa working on it. second of all darpa is not working on it(yet)? they want people to come in and help design it for them. hence the link.

<http://www.darpa.mil/NewsEvents/Releases/2012/12/14.aspx>

but as always, please correct me if i'm wrong

</comment><comment><USER5> Hum, is bandwidth really such an issue when it comes to UAVs? A video stream will consume quite a bit of bandwidth granted but I'd imagine latency to be a much more serious issue. Who cares whether you have a HD video stream if the stream shows you what happened half a second ago?

</comment><comment><USER6> _"One day, you might even have a 100Gbps wireless link from your home to your ISP."_

Probably not, there's far less spectrum reserved for civilian uses than for military per capita.

<comment><USER7> Spectrum can be freed up for other uses, and people continuously make better modulation techniques to make better use of the spectrum.

And there's already a lot of ISPs that provide point to point wireless links. You get an antenna, hook it up outside your office building, point it at the radio tower of the ISP.

</comment></comment><comment><USER8> Wow.. this certainly sounds like a big leap, but I think that this will not succeed during the next 10 years. This would allow an whole army of remotely controlled drones with realtime sensor data and high definition video to operate within a quite large area. How many UAV:s operating within the same area can be nowadays handled simultaneously through one "command center"?</comment>


The biggest bet on longbets.com: $1,000,000 - <AUTHOR> http://www.longbets.org/362

<comment><USER2> Personally, I'm willing to bet anyone a billion dollars that we won't have hyperinflation in the next ten years.

<comment><USER3> They have bets there over whether the LHC will destroy the earth, which is an even bigger asymmetrical devaluation of the winnings.

<comment><USER4> Well, as we all know, there are only two possibilities. Either it does, or it doesn't. That means it's a 50/50 chance for it destroying the earth.

[http://www.thedailyshow.com/watch/thu-april-30-2009/large- ha...](http://www.thedailyshow.com/watch/thu-april-30-2009/large-hadron- collider)

When you've got ominously rounded corridors like that, _you're up to no good_.

<comment><USER5> > That means it's a 50/50 chance for it destroying the earth.

You are joking, are you?

<comment><USER4> Watch the video ;)

</comment></comment></comment></comment></comment><comment><USER6> > Their opposites, passive investors, will by definition do about average. In > aggregate their positions will more or less approximate those of an index > fund. Therefore the balance of the universe the active investors must do > about average as well.

Am I missing something or is this obviously wrong as a mathematical argument? There could be a group of active investors who do well, a group of passive investors who do poorly, and the average would be in the middle.

<comment><USER7> Most (all?) passive investors buy index funds which perform about as well as the market but are more robust because of their diversity. I suppose it is possible for a passive investor to put their money in very carefully chosen index funds that perform poorly, but the whole point of passive investing is that you believe that you're unlikely to be able to make those sorts of allocations correctly and consistently.

There certainly are active investors who do very well, but I'm not sure if there are any that significantly beat the market over a long enough time frame.

<comment><USER8> Buffett's argument wasn't just that active investors don't beat the market over a long enough timeframe (I think some do, he prob agrees).

His argument was that those active investors, _minus the fees they charge_ , won't beat the market over a long timeframe. I agree with him there as well.

<comment><USER9> I agree with Protege that this is an apple to orange comparison. The exact hedge fund is not specified, it could probably invest in anything other than most US large caps represented in S&P500. Heck, it could probably consists of Chinese index funds, which would definitely outperform the S&P if the US spirals into an economic crisis within the 10 years or so.

<comment><USER7> If the US spirals into an economic crisis, I don't see how China could avoid one. China's economy relies on US demand; if Americans aren't buying Chinese goods, then Chinese factories are closing and Chinese exports will crumble. I don't think anyone knows how to raise non-US or internal Chinese demand for Chinese goods fast enough to compensate for a major shock to the US economy.

</comment></comment></comment></comment></comment><comment><USER10> For those who don't know, longbets sends all the funds for any bets to charity.

</comment><comment><USER11> In the poker world, Tom Dwan bet $1M that Phil Ivey couldn't be a vegetarian for one year. Ivey settled after three weeks for $150k.

<comment><USER12> I wonder what a $150k steak tastes like

<comment><USER13> I'd never know. I'd enjoy the taste of a $50 steak and wine, and put the rest into a Tesla Roadster. :)

</comment></comment></comment><comment><USER14> A better bet is, "will the hedge fund have a profitable year in which the market overall is down". If you invest in the market as a whole, you need to be prepared to be in for 30+ years, especially with the levels of volatility we have seen in the last 10-20 years.

A hedge fund can make trades that don't depend on the direction of the market, which means you can access your invested capital even in a down year. Buying an index fund doesn't afford you that opportunity -- if you bought the S&P500 index before the whole mortgage meltdown, you would be out a lot of money now. In 30 years, you probably will have made your 10% per year, though.

(One thing to note, though, is that as an average investor, the trades that make hedge funds / investment banks a lot of money are really not available to you. To make any non-directional money these days, you need cheap capital, and nobody's going to give that to you. I know what sorts of trades pay my salary at an investment bank, and if I made them myself, I would lose money. That's the reality.)

</comment><comment><USER15> This article: [http://money.cnn.com/2008/06/04/news/newsmakers/buffett_bet....](http://money.cnn.com/2008/06/04/news/newsmakers/buffett_bet.fortune/index.htm) provides more information.

Previously, I thought that it was a sure thing for Buffett to win, because I thought portfolio implied maybe 20+ hedge funds, but standing opposite S&P500 are only 5 hedge funds(preapproved by both Buffett and Protege).

Protege has a chance (if i was a betting man, I'd give 1:5 odds they would win).

However, Buffett's bet was smarter, because it also wins if something negative happens to the hedge fund industry as a whole politically and we can see that happening already. Nobody is going to nerf S&P 500.

Also from the article, each side contributed 320k and put the money into zero coupon bonds with maturity in 10 years(ie 640k now -> 1mil in ten years), which will go to winner's charity.

</comment><comment><USER13> Rule of thumb: in the absence of having strong, trustable reasons to do otherwise, always bet the way Mr. Buffet bets.

</comment><comment><USER16> I don't understand how this bet proves anything either way if we can't see the adjudication methodology.

</comment><comment><USER17> What if you die before then does the money come out of the loser's estate?

</comment><comment><USER18> I'm from Omaha... and my money is on Buffet</comment>


Android Encryption Demystified - <AUTHOR> https://blog.elcomsoft.com/2017/05/android-encryption-demystified/ <comment><USER2> There are some inaccuracies and misleading information here:

\- Encryption keys are derived from various inputs including the user credentials, not stored in the TEE. The TEE is involved in key derivation and is really supposed to use a hardware-bound key not directly accessible to software including itself but it's an implementation detail that varies by device.

\- Pixel phones ship with file-based encryption. It's not an option. A phone either uses FDE or FBE. If it uses FBE, then it supports Direct Boot (partial functionally before the user credentials for encryption are enabled via device-encrypted storage class) and per-profile encryption keys. It enables a bunch of possible improvements like authenticated encryption down the road, but isn't much of a security improvement itself. Nexus 5X and 6P only offered a partial implementation as preview for developers tucked away in the hidden developer options, not a user-facing option.

\- Credential-based encryption is enabled by default when setting a lockscreen method.

\- Android has a Keystore, that's not exclusive to iOS.

\- Android doesn't use ECB even though it's implied that only iOS uses unique keys per block. Android does too.

There's some more, but I don't have time to go through and nitpick. It's clearly written based on interpreting other people's blog posts, etc. rather than direct knowledge of how it works or even reading the documentation. It doesn't even sound like they have experience using an Android device based on some statements they make.

The post totally misses out on things like key derivation and which data is kept at rest. The article misses the real remaining iOS encryption advantages (FBE data classes that Android hasn't added yet and more of the key derivation work is hardware-bound) and just tries to make it sound good by stating things that are not unique to iOS.

</comment><comment><USER3> I think this session from I/O 2017 provides a better overview in some regards. Admittedly it's brief on details but the overview is helpful.

[https://www.youtube.com/watch?v=C9_ytg6MUP0](https://www.youtube.com/watch?v=C9_ytg6MUP0)

</comment><comment><USER4> I can't quite understand why Elcomsoft are still going.

1\. They're being stiffed by Google and Apple upping their security game, hence the amount of complaints on this blog in the comments

2\. Their users all seem dodgy as fuck, it's not even funny.

3\. Passwords and 2fa are making their brute force methods completely outdated

Why haven't they shut down yet?

<comment><USER5> Because governments and forensic companies buy their tools.

"Completely outdated" you may say - but most people still don't use these things. Most people won't go out of their way to take anything more than the most basic security measures. So that's good enough most of the time for forensic purposes.

Apple's "secure by default" concept sounds like the best practice in theory, but their backups and account tying of devices make it so that there's easy attack vectors for tools like this. In order to fully take advantage, you'd have to have never taken a backup of your iOS device and have all iCloud features disabled. Most people don't do that, most people would rather get their data back if they forget their password than keep them private in an extreme situation - for most people that probably makes sense.

</comment></comment><comment><USER6> My problem is that I had full encryption enabled on Marshmallow, upgraded to nougat and my system settings say that encryption is enabled even though I strongly suspect it isn't - my phone used to ask me for pin before booting up, but now it doesn't, so I suspect the encryption was removed while upgrading but the system settings are showing the old value for whatever reason. And I can't really wipe my entire phone just to re-enable the encryption, it's a lot of work to set up all apps again. Xperia Z5.

My point is that android encryption has problems if you can just lose the encryption between os version upgrades.

<comment><USER7> Since Android 7.0 the OS can boot without the encryption key just like Android. Absolutely nothing was removed.

<comment><USER6> Huh. Well, it would be nice if it was announced in some way, I genuinely though about wiping my phone because of this.

<comment><USER7> It was - for people that cared about implementation details. Look for articles about so called Direct Boot.

</comment></comment></comment></comment><comment><USER8> How does it work with a pattern lock? Is the pattern used to calculate the encryption key?

<comment><USER9> Careful with that! I updated a Nexus 7 (flo) recently to Lineage OS, set a pattern lock (using one of the larger or the largest grid - mostly Just Because™). Enabled encryption. Tablet rebooted and asked for my input to decrypt, presenting a 3x3 grid.. :-)

Wasn't a big deal for me, since I just tried to revive that thing anyway. But that seems like a bad idea..

</comment></comment><comment><USER10> this is one the only articles i've ever read where "honking" is used in a serious capacity as an adjective.</comment>


Using geometry to solve algebraic problems - <AUTHOR> http://mathpages.blogspot.com/2008/07/using-geomety-to-sole-algebraic.html <comment><USER2> Someone ought to invent a way to solve geometric problems using algebra.

<comment><USER3> Yes, somebody named Descartes. [<http://en.wikipedia.org/wiki/Cartesian_geometry>]

Or, if you prefer a more modern subdiscipline, there's algebraic geometry. [<http://en.wikipedia.org/wiki/Algebraic_geometry>]</comment></comment>


Boeing's folding wingtips get the FAA green light - <AUTHOR> https://www.engadget.com/2018/05/18/boeing-folding-wingtips-faa-777X/ <comment><USER2> I'm glad the FAA does what they do. While it is easy to hand wave away their concerns, it is better to over-spec it now and to test the design than to just let manufacturers put "alpha" products into commercial usage and only fix them after a body-count.

If driving/vehicles/roads were held to the same or a similar standards to aircraft there might be fewer accidents and deaths today.

Ironically self-driving is held to a much higher standard than regular driving; which is appreciated but further makes one question why regular "dumb" vehicles are so under-regulated (the analogy that springs to my mind is when HTTPS with a self-signed certificate used to be treated much worse than regular HTTP, it took years to treat HTTP as the insecure connection it is, manual vehicles are the same way, something that has been around so long we ignore its safety issues).

<comment><USER3> Bringing the same rules to light aircraft as airliners has actually made them less safe. Bringing a new four place plane to market has been cost prohibitive. The majority of new planes built today were designed in the 50's on slide rules. Imagine if we were all still driving 50's era automobiles. Luckily, the FAA loosened these rules this week.

<comment><USER4> > The majority of new planes built today were designed in the 50's on slide > rules.

That's not true.

Of the 15 most popular light aircraft models built in 2015, only one was introduced in the 1950s: the Cessna 172. And even that one underwent a pretty substantial overhaul in 1998. The most popular light plane sold in 2015 was the Cirrus SR22 with 270 units sold. The SR22 debuted in 2001.

Source: [http://www.fi-aeroweb.com/General-Aviation.html](http://www.fi- aeroweb.com/General-Aviation.html)

<comment><USER5> >Of the 15 most popular light aircraft models built in 2015, only one was introduced in the 1950s: the Cessna 172.

It's disingenuous to say that and not talk about numbers. There were over 44 thousand of them built, and they are literally _the most produced aircraft ever_. Cirrus is a blip on the radar compared to Cessna.

At 300 planes/year they will not catch up with Cessna in a _century_ even if Cessna ceased to exist today!

In fact, the top six most produced civilian aircraft ever _that are still in production_ are[1]:

Cessna 172 (1950's)

Piper PA-28 (1960's)

Cessna 182 (1950's)

Cessna 152 (1950's)

Antonov AN-2 (1950's)

Beechcraft Bonanza (1950's)

Do you have the statistics on the market share of the "slide-rule" planes today? Not as a percentage of planes _being built or sold_ , but of the ones in service. I'd bet on them being the majority.

[1] [https://en.wikipedia.org/wiki/List_of_most- produced_aircraft](https://en.wikipedia.org/wiki/List_of_most- produced_aircraft)

<comment><USER4> No, it is not disingenuous because the topic at hand is "the majority of new planes built _today_."

Obviously if you look at production through all of aviation history you are going end up overweight in older models. But that is just a reflection of the fact that planes are generally designed and built to last. It has nothing to do with the current state of the art, which is what the OP was lamenting.

<comment><USER5> OK. You are correct, you have refuted the point that the majority of planes built today are of older designs.

The point we were discussing is that excessive regulation on light aircraft prevents innovation by driving the cost prohibitively up and thus leading to a decrease in sales of new designs.

It is not clear to me that the argument that the industry overall is less safer is invalid if most of the planes flown are old, and if over-regulation of light aircraft is the cause of that.

We do need the statistics on the numbers of old-design planes in the air, together with the pricing data, statistics on sales which include old planes, etc.

<comment><USER4> Wow, new planes cost more than old planes. Who knew?

<comment><USER5> New planes today cost more than new planes used to cost back in the day (accounting for inflation), which creates more demand for older planes.

Cessna 172 cost under $9000 in 1956 when it was introduced, which is about $80K today when accounted for inflation.

Do you know of any similar _new_ aircraft in the same ballpark? Last time I checked, $50K still gets a _Cessna 172 built in the 70 's_. A new Cessna 172 seems to be north of $250K, depending on configuration.

Cirrus SR22 is north of $550K.

Civil aviation has definitely become a richer man's game over the past 5 decades; the question is _why_ this happened.

To be clear: a middle-class enthusiast really _can 't_ afford to buy the best- selling plane of the year _new_ today, while that was a realistic option in the 1950's.

1\. Do you not think this is bad?

2\. What do you think are the causes of that?

<comment><USER4> These are very different topics from the original one under discussion, and much more complex. I don't know why it should matter to you what I think about this, but since you asked, no, I don't think the increased cost of aircraft is bad. Aviation is a very environmentally destructive pastime, so high barriers to entry are a good thing.

As to your second question, liability concerns and government regulations certainly add a lot to the cost of an airplane. But the flip side of that is that modern airplanes tend to be pretty darn safe. As a pilot, I think that's a good thing too.

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER6> > The FAA rubber-stamped those measures Friday.

Not sure what this line is supposed to mean. Is he referring to them approving them without knowing what they are?

I'm glad for the FAA's rules. U.S. air travel is extremely safe despite constant efforts on the part of airlines to reduce costs for themselves without enough concern for safety. I don't think we can trust any transportation company to value the lives of its passengers at an appropriately high level so they need to be forced with regulation.

<comment><USER7> Boeing and the FAA proceed on these things as a partnership. Boeing has their name on the line, and they have way more engineers and other technical specialists than the FAA. In the past, Boeing has essentially written the specs that must be adhered to by all equipment producers, and, once the FAA approves those specs and procedures, ensures that they are followed. This book gets into how this worked with the 747:

[https://www.amazon.com/747-Creating-Worlds-Adventures- Aviati...](https://www.amazon.com/747-Creating-Worlds-Adventures- Aviation/dp/0060882425)

<comment><USER8> Boeing is part of a duopoly. If a Boeing plane falls out of the sky, most people would chalk it up to the inherent danger in air travel rather than to fault Boeing specifically.

OTOH, part of the reason the duopoly persists is because of heavy regulation, and specifically the strict safety regimen. From that angle Boeing has significant economic motivation to promote costly safety margins, particularly those which raise barriers to entry into their markets.

I understand the argument that Boeing employs countless conscientious, professional engineers. But in 2018, with American business culture having internalized decades of cynical, anti-social business practices, I'd be careful about overestimating the influence of the professional class.

<comment><USER9> > OTOH, part of the reason the duopoly persists is because of heavy regulation

Also because Boeing was ultimately more successful than the third competitor in the market. Boeing sold many aircraft during a period in time when the DC-10's reliability was deeply questionable in its early years, due to some aircraft design/engineering related fatalities that killed hundreds of people. There have been a shitload of fatal Boeing accidents including things like the 747-vs-747 crash in the canary islands, a Japanese airline 747 that flew into a mountain, etc, but those were all caused by human factors.

There have been very few large fatality crashes that can be directly traced back to an inherent design flaw in a Boeing plane.

<comment><USER10> Just a couple from memory:

There were several fatal 737 accidents due to uncommanded rudder actuation.

The earlier 707 also had several cashes linked to rudder design and the UK CAA required design changes before it was permitted on the UK register.

</comment></comment></comment></comment></comment><comment><USER11> I wonder why one would not make the wingtips fold down..

Thus providing the opportunity to provide a permanent thrust face for the majority of the in-flight forces and thus significantly reducing any risk of failure.

There apears to be adequate ground clearance.

<comment><USER12> They want to avoid the inevitable "ground crew drove a van into the wing tip"-delays.

</comment></comment><comment><USER13> I wonder what the failure modes for this would be like.

Consider a Boeing 777X going along at its cruising speed and the locking mechanism for the wing tips just disappears; primary and secondary. The wingtip is effectively unsecured. What happens?

<comment><USER14> If we're going to do failure modes effects analysis, we'd need to know what the mechanism is in order to enumerate the possible failure modes (along with their likelihoods). For example, if the wing tips are actuated by a worm drive, then there is no "and the locking mechanism...just disappears;" The drive would be the locking mechanism. There are probably also suitable bistable mechanisms that lock in the open and closed positions, requiring actuation to unlock them.

> What happens?

In the large, I'm sure the teams of engineers at Boeing have it covered.

<comment><USER15> The conventional locking mechanism that I've seen documented is like the lock on a bank vault: several pins, aligned with the hinge, which slide parallel to it, locking inboard and outboard sections in place. This locking mechanism means that the number of pins and their dimensions can be scaled to handle arbitrary loads, and there's no single point of failure.

<comment><USER13> Thats what it looks like just looking at the video. Some kind of pins that slide in when the hinge is fully down.

So one in a billion confluence of errors makes the pins disengage in the middle of a flight. What happens?

<comment><USER15> Well, the lift on the wingtip is going to make it fold up. In the worst case, I guess it might break off, but it's a very small part of the wing, and it presumably doesn't contain fuel tanks. Chances of it damaging the inboard section have to be quite small and I wouldn't be surprised if the hinge is designed to cope with the forces involved.

For comparison, see these stories of aircraft flying safely with a much larger wing area unintentionally folded: [https://theaviationist.com/2014/02/19/us- navy-fighters-folde...](https://theaviationist.com/2014/02/19/us-navy- fighters-folded-wings/)

<comment><USER16> It might not even fold up. The wingtip probably incorporates some amount of wash-out (reduced or even negative angle of attack, as compared with the wing root) There might not be much or any upward force on it. Depending on how the actuators work, they may be strong enough to hold the wingtip in place without the locking mechanism.

<comment><USER17> If there's little or no upward force on it, they might as well not have the wingtips since they wouldn't be generating lift!

(devices such as winglets excepted; I don't think that applies here)

<comment><USER18> > [...] except for devices such as winglets

You answered your own question and didn't know it.

If the additional width added here has no net lift benefit but served as winglets do to reduce induced drag from the 'mixing boundary' but even more effectively – since the outward moving airmass doesn't have to accelerate (read: change direction) when it hits the base of the winglet, but instead gets to continue smoothly migrating to the tip – I can absolutely see how that would pay off in efficiency gains.

Wings can be designed to have nearly arbitrary amounts of lift: reducing drag for a _given amount_ of lift is the secret sauce, which could very well be what this design achieves.

(me: FAA Licensed Dispatcher)

<comment><USER14> Licensed to dispatch planes or not, everything you've said about fluid dynamics is wrong. You first seem to have confused "winglets" with "vortex generators." I think. The only winglike thing that messes with the viscous boundary layer is a VG. Second, winglets have nothing to do with a "mixing boundary;" They do what they do, even in completely inviscid flow, where there is no boundary layer. Third, whether an air mass has to "accelerate" has nothing to do with efficiency. For example, air is adiabatically compressed as it meets the stagnation point on a wing, or en masse as it enters a subsonic diffuser (jet intake). The former is a consequence of fluid flow in general, and the latter is by design. Both are completely isentropic and lead to no total pressure losses in the flow.

Finally, it's meaningless to say that wings "can be designed to have...arbitrary amounts of lift," and plainly incorrect to say that drag is the "secret sauce." (Aeroelastic flutter? Wing mass? Control moments? Moment coefficients?) Reducing induced drag is done in exactly two ways. You either increase the span or put a winglet on so you can _effectively_ increase the span while still being able to park the plane.

Nobody thinks they can do brain surgery, but everybody is a fluid dynamicist.

<comment><USER15> This reply is so gratuitous.

It would have been enough to say that wing extensions in general (winglets and the 777x ones included) serve to improve the overall efficiency/performance of the wing (so they might not be generating any lift at all, if it's even possible to analyze them in isolation).

It's fine to make the point that we're all unqualified to discuss this because we aren't fluid dynamicists. But dumping a load of technical language on us that you don't expect us to understand is a rude, non-productive, and self- aggrandizing way to do that.

<comment><USER18> I sought only to say how the upside could be something other than lift increase (in the absence of any white papers from Boeing or the like) and provided some loosely framed concepts that support that possibility.

I would address the GPs nit-picky points, but the tone is so snarky it's not worth my effort. I may not be a fluid dynamicist, but neither am I a pedantic putz. (subtext: chill out, dude.)

<comment><USER15> To amplify the sentiment a little bit: the guy who invented winglets did so based on physical intuition, not calculation.

[https://en.wikipedia.org/wiki/Richard_T._Whitcomb](https://en.wikipedia.org/wiki/Richard_T._Whitcomb)

He was such an intuitionist that AFAICS he apparently spent some of his last years on perpetual motion machines (i.e. some kind of quantum zero-point energy device.)

The idea that it's not OK to have spirited discussions about this, that the science should dictate who is right and who is wrong, is just inadequate to the problem. The design space for aircraft is huge, and almost any conceivable practical technique or configuration is going to be conventional, based on experience.

</comment></comment></comment></comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER19> I thought a wider wings would cause more drag? What am I missing?

<comment><USER20> You'll be interested to read about aspect ratio: [https://en.wikipedia.org/wiki/Aspect_ratio_(aeronautics)](https://en.wikipedia.org/wiki/Aspect_ratio_\(aeronautics\))

As the ratio of the span to the chord increases, the ratio of lift to drag increases as well.

The drag of an object in the sense of forcing its way through the air (eg a semi truck on the highway) is important, but for airplanes there is also a very important phenomenon of drag due to lift ("induced drag"). It's kind of non-intuitive. But if you've ever seen those strong vortices coming off a wingtip, you're seeing induced drag. Think of the energy creating this: [https://youtu.be/uXrnGiIMGLs](https://youtu.be/uXrnGiIMGLs)

It's energy created by propulsion but turned uselessly into spinning air.

<comment><USER21> You beat me by two minutes on the aspect ratio bit :)

Here's another good video showing wingtip vortices: [https://www.instagram.com/p/BhzCLgFnVzL/?hl=en&taken- by=edse...](https://www.instagram.com/p/BhzCLgFnVzL/?hl=en&taken-by=edseguin)

Not sure what you mean by "energy created by propulsion." The vortices result from low pressure on top and high pressure below making the air want to curl around. That imparts downwash on the wing, reducing its effectiveness.

<comment><USER20> I mean that the airplane's propulsion system is ultimately the power source behind those vortices, by forcing the wing through the stationary air.

</comment></comment></comment></comment><comment><USER22> Sort of off topic, but sort of related too. How do you differentiate between the types of planes Boeing makes? I know the 737, 747, 757, 777, and 787 are all different but never really understood the meaning behind the numbers. I know certain pilots can fly certain ones, but I've never gotten the similarities between the designs and why that is.

</comment><comment><USER23> "The FAA also wanted assurances that there was no way the tips would rotate during flight".

Does "no way" include the pilot deciding they should? If so this goes against tho grain of the philosophy that the pilot should be in full control of the plane. Interesting that they made an exception for this.

<comment><USER24> Usually yes.

> If so this goes against tho grain of the philosophy that the pilot should be > in full control of the plane.

Clearly not. Pilots are usually prevented from destructive actions unless there's a good reason for it or a technical impossibility (and for a large object flying at a large speed, there are several ways they can do something wrong)

If there's no technical reason why they should be allowed to unlock the wingtips in flight, they will be prevented from that.

</comment></comment><comment><USER25> To be honest, all these advancements in plane efficiency and design, is irrelevant to me, as a passenger.

Why? Because the airlines will continue to cram you like a sardine in a can, and will give you barely any sitting space on the plane.

Unless of course, you pay for it, to fly first class, or business class.

And to the capitalists, then this is perfect. It's exactly what a market economy system is all about. You as the consumer, get what you pay for.

What is troubling is flying coach on a long haul international flight, that lasts for over 10 hours. There just isn't any room to move around in your seat. Sleeping during the plane is uncomfortable, if can even do so. And good luck if you end up sitting in the middle. Nobody wants to sit in the middle.

If there is one thing that the FAA should regulate, it is the minimum space allotted to flying coach on a flight. Give us back some human decency please.

</comment><comment><USER26> What does it actually take to get a thing allowed? What are the specific requirements?

</comment><comment><USER27> > some plane crashes occurred after pilots did not secure flaps on wings > before takeoff. The FAA required Boeing to have several warning systems to > make sure pilots won't attempt a takeoff before the wingtips are locked in > the correct position.

And Boeing couldn't imagine that might be a good idea in the first place?

<comment><USER19> Shouldn't they automatically lock? In what scenario do you want wings down and unlocked?

<comment><USER28> I guess it's hard to awnsers have we landed and should we move the wingtips to locked positions? Airplanes afaik have no state machine that says taking off landing taxiing. They may be able to detect it by reading all different systems example landing gear extended altitute from ground radar over 4 feet landing wheel moving etc. But I assume it's too many variables?

</comment></comment></comment><comment><USER29> The correct term for these is winglet, which is a special kind of wingtip device. There are other wingtip devices too. For example A380 has wingtip fences.

<comment><USER16> These are not winglets.

Winglets are fixed. These are new longer wings, which would make the aircraft too wide to use existing terminals, except that Boeing have built the wingtips to fold up while taxying and at the gate. In flight they are extended straight out as extensions of the wings.

Winglets are cool, but a longer, straight wing can achieve the same effect more efficiently by giving the wingtips washout (negative angle of attack).

<comment><USER29> My bad! Thanks for the correction!</comment></comment></comment>


Smarter Link Underlines For Every Website - <AUTHOR> https://eager.io/blog/smarter-link-underlines/?utm_source=hacker_news <comment><USER2> It's a very nice idea — I always like smartening up the look of the Web — but the resulting links are ghastly. If your word starts or ends with a descending letter (e.g. "ghastly"), then the underline looks like it omits the first and last letters. It breaks the semantics of what the underline means — any bit that's underlined is supposed to be the link, and if it's not underlined it's not a link.

They also made the mistake of showing a link that includes the word "Typography", which has an underline so broken up and interrupted that it's distracting (which devindotcom also pointed out). It's linked, then it's not, then it's linked, then it's not!

So yeah, I have to give them credit for a good idea and a clever implementation, but it just doesn't work out in the end.

<comment><AUTHOR> I appreciate your feedback. No doubt on some level this comes down to aesthetic preference. I'm curious though, on the before-and-after examples on the homepage [1] do you feel that _all_ of the afters are worse?

You and devindotcom did indeed bring up some good points, particularly about descender-heavy links, something I plan to take a crack at [2]. But I'm curious if you feel the entire strategy is flawed or if there's just more work to be done. On a related note: if you've used/seen it, how do you feel about links in iOS 8 Safari? How do you feel about this before-and-after [3] (screenshot of the first paragraph of the blog post)?

[1]: [https://eager.io/showcase/SmartUnderline/](https://eager.io/showcase/SmartUnderline/)

[2]: [https://github.com/EagerIO/SmartUnderline/issues/1](https://github.com/EagerIO/SmartUnderline/issues/1)

[3]: [http://postimg.org/image/rgfx5icq9/](http://postimg.org/image/rgfx5icq9/)

<comment><USER3> Well, I realised what was bugging me and why I prefer the iOS implementation for now -- the tighter underline, both a pixel closer to the baseline and a hair closer to each descender, helps ensure the underline feels continuous even when it's broken this way. I do prefer this approach for headlines or animated effects, but perhaps (as was suggested elsewhere) changing the underline colour and/or tightening the spacing would help. A neat implementation though. Seeing links here, it's true, the "g"s just seem to get demolished by the underline. I wonder, if I linked to qithub.com, would you see the difference? ;-)

Oh and if there's a way to apply this without requiring a background color, I suspect this might be a popular add-on or browser setting for some folks.

<comment><AUTHOR> See my comment above [1]. I think you'll find that the iOS 8 and SmartUnderline implementations are closer than you think.

[1]: [https://news.ycombinator.com/item?id=8588492](https://news.ycombinator.com/item?id=8588492)

</comment></comment></comment></comment><comment><USER4> To me, it actually adds visual complexity while eliminating the useful visual cue of a single line being a single link. Here, there are many lines, which to me indicate many links. In some cases, the line may present as dotted or dashed (the word "piggy" randomly came to mind) — things that signify something other than a link to me.

I would rather descenders weren't subsumed by the line either, but interrupting the element itself instead seems like as much as a problem as it is a solution.

<comment><USER5> You can also see some dotting/dashing in the link on the page to the Butterick book.

I have a hunch using a faded color for the (possibly-then-thicker) underline would work better - the foreground descenders would retain distinction, without the noise of dotty/dashy line-ends.

<comment><AUTHOR> Thanks for the suggestion. We'll be taking a crack at descender-heavy links [1], so this may come in handy!

[1]: [https://github.com/EagerIO/SmartUnderline/issues/1](https://github.com/EagerIO/SmartUnderline/issues/1)

</comment></comment></comment><comment><AUTHOR> In order to more accurately compare iOS 8 Safari's text-decoration underline implementation to SmartUnderline, I created a test page. [1] It contains five links to the words gesture, quitting, discovery, piggy, and eager, set in Helvetica.

To produce the iOS 8 version, I opened the page in Safari on iOS 8.1 pinched zoomed to the maximum amount while keeping all five links within the frame, and took a screenshot.

To produce the SmartUnderline version, I visited the SmartUnderline install page [2] in Google Chrome on Mac OS X, entered the test page URL, and clicked "Preview in a separate window". With the screenshot from my iPhone opened next to the browser, I used Command+[+/-] to zoom the browser until the font sizes were the same size, then took a screenshot.

Here are the results: [3].

To summarize, I believe iOS 8 has some advantages and some disadvantages, but to me there is no clear winner.

Some specific points in no particular order:

\- iOS underline breaks are always vertical cuts. Since SmartUnderline uses text-shadow to "white-out" the underline, the cut-outs are in the shape of the glyph. To me, this looks better in the "g" in "eager", but worse in the "q" in "quitting".

\- iOS 8 shows a line between a "g" and "y" (as in "piggy") and SmartUnderline does not.

\- SmartUnderline's underline extends less far to the left of the first letter and right of the last letter. This looks better in "quitting" and potentially worse in "discovery".

\- In general, SmartUnderline sets a little more space around each descender.

\- Both implementations show no underline before or after a leading or trailing "g".

\- Both implementations show the underline very close to the left side of the "y" descender. I think improvements could be made here with both implementations.

[1]: [http://jsfiddle.net/adamschwartz/hyyerbq4/show/light/](http://jsfiddle.net/adamschwartz/hyyerbq4/show/light/)

[2]: [https://eager.io/app/eA9ULux0UOJP/install](https://eager.io/app/eA9ULux0UOJP/install)

[3]: [http://postimg.org/image/nf9b2ahd1/](http://postimg.org/image/nf9b2ahd1/) (@2x [http://postimg.org/image/688ricy2v/](http://postimg.org/image/688ricy2v/))

<comment><USER6> Fyi: Postimg.com gives me a popup with "watch free hd movies now" and redirects me to some gambling page. When going back, I can see your image between some half naked guys. You may want to use something a bit more serious in the future.

<comment><USER7> Imgur mirror of the 2x: [http://i.imgur.com/KD7k0Rz.png](http://i.imgur.com/KD7k0Rz.png)

</comment></comment></comment><comment><USER8> This kind of underline painting behaviour is proposed in [http://dev.w3.org/csswg/css-text-decor-3/#text-decoration- sk...](http://dev.w3.org/csswg/css-text-decor-3/#text-decoration-skip- property) as text-decoration-skip:ink. Not yet implemented anywhere though.

</comment><comment><USER9> Neat, though I don't actually think I like the look of it. I think I'd rather have an underline further down, so that it's below the descenders.

<comment><AUTHOR> No doubt, at a certain point it does come down to aesthetic preference.

Using a border-bottom to achieve the look you're describing is totally a valid preference. One potential advantage to the border-bottom technique is the way it can be used to make a link stand out. In fact, I use this link styling on my personal website for that reason [1].

(Note: when using a border-bottom, I'd recommend using a slightly larger line- height so that the line still seems associated with the text above it and not the text below it. This is one of the pitfalls described in the original Medium post [2].)

Unfortunately, aside from iOS 8, normal text-decoration underline links have the descender crossing problem.

I absolutely took this into consideration when designing SmartUnderline. SmartUnderline literally only applies itself to links with text-decoration underline, nothing else. It even tries to ensure other conditions which make the transformation favorable (display inline, solid background color, etc.).

Ultimately I think the before-and-after on the SmartUnderline website tells the best story [3]. No doubt one may appreciate other, very different link styles. (For example, just using a different text color to denote _link_ is a perfectly valid and commonly used technique.) But if you're using text- decoration underline already, this just makes those links look better.

I think blogs, news articles and wikis are some of the primary examples of where these links look best. Anywhere where text is heavy and the links are _not_ the primary focus.

[1]: [http://adamschwartz.co](http://adamschwartz.co)

[2]: [https://medium.com/designing-medium/crafting-link- underlines...](https://medium.com/designing-medium/crafting-link-underlines- on-medium-7c03a9274f9)

[3]: [https://eager.io/showcase/SmartUnderline/](https://eager.io/showcase/SmartUnderline/)

<comment><USER10> I think this is very clever and I appreciate the work you've done to make it so robust. I'm not a designer, but I like to think I can appreciate at least some of really good work. Your pages qualify there.

One note on your before and after, it's cool that you included arabic, but the right to left nature makes it look like the examples are reversed. Though I realize perhaps that was intentional.

<comment><AUTHOR> Thanks!

Ha! Yeah, my co-founder and I debated that one... (he thought I should reverse it). I can see it both ways, but your comment certainly puts another vote in the reverse-it column. Thanks again :)

<comment><USER11> I was about to send a PR for the reverse; then I realised what language it is. Perhaps having the columns not centered but reading-direction-aligned would make it clearer. Not sure there. But I'd keep it that way, it's rare enough that people treat RTL languages properly when they don't know them ;)

</comment></comment></comment></comment></comment><comment><USER12> _> First we define a helper mixin textShadowToCropUnderline which draws 12 text-shadows, half to the left, half to the right, spaced every .03em._

This seems like a big waste of CPU and memory. I don't want to drain my phone's battery rendering these underlines.

<comment><AUTHOR> In our tests (scrolling an older iPhone on a page with 300 links), we found that it's actually not as much an issue as you might think, particularly because none of the shadows use a spread value. I'd definitely be interested to see if you have evidence to the contrary.

That being said, it's definitely something worth considering, particularly since iOS 8 now implements descender-aware link underlines now. If there were a way to duck type for this feature, we'd definitely disable the JS anywhere we detect it working. Drawing an underlined "g" on a canvas and then reading the pixels at a certain location may work, but we haven't tried it yet.

</comment></comment><comment><USER13> I had seen this effect about two years ago on the website of Roman Komarov and was impressed by it at the time: [http://kizu.ru/en/fun/](http://kizu.ru/en/fun/)

<comment><AUTHOR> I really like how he applies the styles on hover. I wanted to do something like that with SmartUnderline but unfortunately there is no way to call getComputedStyle with the :hover pseudo-class applied. (This is necessary because SmartUnderline only applies to links which have text-decoration underline.)

Traversing the enter style ruleset is possible but didn't seem worth it for a library like this.

Another way is through a configuration option. Something like `SmartUnderline.init({ '.content a': 'hover' });` perhaps.

</comment></comment><comment><USER14> While I admire the attention to detail, it is all in vain for me. I much prefer the simplicity of a solid line to the awkward fragments dodging descenders. My brain continuously tries to make sense of the incomplete line, and some words no doubt will add to the confusion with long stretches of characters having minimal expression of the underline.

Case in point, the word giggly has what appear to be specs of dust underneath.

</comment><comment><USER15> Why limit yourself to just underlining links? Why not some other convention? I played around with this a bit over a decade ago: [http://www.conman.org/people/spc/writings/hypertext/fragment...](http://www.conman.org/people/spc/writings/hypertext/fragment/) (note: In the twelve years since I wrote that, most of the links offsite are now dead, which is another issue with links).

At first, the links in the "fragment" are invisible. You can toggle among that, single angle quotes (not used in English, which is why I picked that option), small bullet points on either end, and the default HTML underline.

<comment><USER16> FWIW, my experience with your link:

The lack of any indicators at all was frustrating. I had to take physical action to determine whether something was a link. In practice I think I would just stop using the links. I think some kind of indication is needed.

The default underline was the best for me. I don't rule out that this is because I am used to the underlines. Going in I thought the dots would be bets, but I found them distracting. With practice they might be the best.

The angle brackets were by far the worst. It could be because I have seen enough HTML for angle brackets to have singificance, but I think it has more to do with parantheses and how we use them in text. I just found them distracting and they really took me out of the work.

Of the cuff thought... small superscripted dot or something? I'm used to seeing footnote or citation indicators in the corners and they generally don't take me out of whatever I'm reading.

<comment><USER15> The dots are small to begin with, any smaller and they might not be seen. There might be other, visible but not underlined techniques.

</comment></comment></comment><comment><USER17> The library's showcase page has the key bits imo:

> \- It makes an assumption about selection color, which is OS- and browser- > dependent.

> \- Each smart-underlined link has 12 text-shadows drawn underneath it, which > could potentially have performance penalties on mobile or older devices.

[https://eager.io/showcase/SmartUnderline/](https://eager.io/showcase/SmartUnderline/)

(Imho, the two points introduce enough risks and reasons to not use it and wait for OS- or browser-level updates instead.)

</comment><comment><USER18> This seems like something user agents should apply to all 'underline' text- decoration by default in order to improve readability. Is there any reason not to?

<comment><AUTHOR> iOS8 Safari agrees with you. :) (As do I fwiw.)

Unfortunately I imagine this is easier-said-than-done and may have to do more with the underlying typographical engines of OS-s than browsers. (I'm just guessing though.)

<comment><USER18> Ah, an excellent point. The TrueType font format apparently does specify an underline position and height [1], though there's no mention of any allowance for this descender-dodging feature. The fact that font formats defer the actual drawing of the underline to the renderer gives me some hope. This seems to highlight the issue of web browsers having different font rendering needs from other apps, since underlining is so much more prevalent.

[edit] Obviously, it's a lot easier to fix this issue with a single font, as Apple has done in Messages, than to fix it well in every font.

With regards to this implementation, I'd rather not have to worry about the background, font and select background colors for every link. Applying text shadows over gradient-drawn underlines is an inspired hack that I'll have to remember, just in case, but I really wish there were a better way.

Maybe we should push for a 'text-mask-underline' CSS property that accepts radius, hardness and opacity values, in order to apply a fade to the underline around text descenders. [/edit]

[1] [http://fontforge.github.io/fontinfo.html](http://fontforge.github.io/fontinfo.html), [http://scripts.sil.org/cms/scripts/page.php?site_id=nrsi&id=...](http://scripts.sil.org/cms/scripts/page.php?site_id=nrsi&id=IWS- Chapter08#05931f9d)

<comment><AUTHOR> Thanks for that information re:TrueType! My knowledge of these things tends to end at the browser, but I too hold hope for better type in future OS-s.

The fact that Apple decided to tackle this on iOS, an OS used on handheld devices which are typically viewed at closer distances, tells me that it's something they feel is worth doing when you have the display resolution to do it right.

SmartUnderline makes a similar assumption, not applying itself to links with a small-enough font-size computed style.

With respect to your [edit] block:

> Obviously, it's a lot easier to fix this issue with a single font, as Apple > has done in Messages.

Apple has implemented this throughout iOS 8, not just in Messages. Here's a screenshot of Safari [1].

> I'd rather not have to worry about the background, font and select > background colors for every link.

That's actually the beauty of SmartUnderline. It figures all of these things out for you, automatically [2]. Please let us know if you run into any trouble though. :)

[1]: [http://postimg.org/image/4ncgrezxr/](http://postimg.org/image/4ncgrezxr/)

[2]: [http://git.io/9YNfgg](http://git.io/9YNfgg)

<comment><USER18> Re: [2], nicely done! For a dirty hack around browser limitations, it is well implemented. It's a good thing gradient backgrounds behind text are out of style. : P

<comment><AUTHOR> Thanks!

If a background-image is specified, we abort [1]. (This would apply to CSS gradients as well.) Of course we'd like to support non-solid backgrounds at some point, but short of a true HTML-to-canvas solution, there's not really that much better you can do without wreaking lots of havoc.

[1]: [http://git.io/1WqsAA](http://git.io/1WqsAA), [http://git.io/n4tRrw](http://git.io/n4tRrw)

<comment><USER18> Is this only getting the first container's background? If so, what happens when a layer below that has an image or gradient bkg?

<comment><AUTHOR> Nope, it traverses up the DOM until it finds an element which has any non- transparent background. If the first thing it finds has a background-image, it aborts. If it's a solid color, it returns that container. [1]

This absolutely still is prone to bugs when `position` or other properties are used to move elements visually outside of their parents, but it's about as good as you can do without a true HTML-to-canvas implementation.

[1]: [http://git.io/ChvO3Q](http://git.io/ChvO3Q)

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER19> This example shows once again that CSS is not a good declarative language: it provokes hacking. In this case, a hack has to be applied in every instance where this is needed.

Instead, if CSS were developed by actual language designers, it would have been possible to write this as a modularized thing, completely hiding the actual implementation.

</comment><comment><USER20> Aside from the many other criticisms raised in the comments, this seems like something of a deal-breaker to me: "It requires that the text be on top of a solid background color."

<comment><USER11> It's a restriction, yes, but far from a deal-breaker, I'd say. There are very, very many websites out there that have text on solid-coloured backgrounds.

</comment></comment><comment><USER21> This seems like a hell of a lot of client-side processing just to enforce a trivial (and arguably bad) typography preference.

</comment><comment><USER22> Web 1.0 called and they want their underlined links back.

<comment><USER23> I'm confused, is there some other way we're supposed to indicate something is a link now? I thought was considered bad practice to mess with link styling too much for usability reasons.

</comment></comment><comment><USER24> That's nice in theory, but it's also yet another example of Apple innovating and getting it right, and people implementing a quick copy without going through nearly as much _necessary_ design thinking as Apple did. The end result is that only Apple's implementation is better than the default one. Of course I'm not blaming you personally for that, I mean, even Microsoft has fallen prey to this phenomenon (and on a vastly larger scale). But it would nice if people were more observant.

<comment><AUTHOR> I appreciate your feedback. There are always ways of improving something, even in the case of Apple's implementations.

Are there particular aspects of this implementation you feel make it worse than Apple's?

Ultimately we see this as an incremental improvement to the default text- decoration underline styling provided by most operating systems and browsers. However, we're eager to work with OS community to improve this even further. Thanks again!

<comment><USER24> Sorry somehow I thought that was obvious. Basically they cut the line very close to the letter, that way it doesn't break the line visually, which is what the other comments here on HN seem to criticize. It's a very simple and subtle thing but that's what makes the difference. My point was that sometimes the incremental steps between the default design and Apple's design are worst than if you just kept to the default design. You have to make a big step before perceiving benefits. Sorry for the pigeonholding though, that was more of a general rant.

<comment><AUTHOR> See my comment above [1]. I think you'll find that the iOS 8 and SmartUnderline implementations are closer than you think.

[1]: [https://news.ycombinator.com/item?id=8588492](https://news.ycombinator.com/item?id=8588492)

<comment><USER25> You keep repeating that comment but no, they are not. The idea is clever and the result is pretty good, but what the parent is saying – that in your implementation the line looks more broken up because it's more separated from the glyphs – is true.

You may be able to fix that by tweaking the shadows but as it is currently implemented it works pretty well for larger display text but not so much for smaller body text.</comment></comment></comment></comment></comment>


What do you think about newLISP, a scripting language that claims to be a LISP dialect? - <AUTHOR>

I'd like to hear opinions, impressions, criticism about it. Would it be a considerable language for professional or secure programs?<p>For those who still don't know it: http://www.newlisp.org/ <comment><USER2> [Diplomatic Hat On] I would personally stick with a Scheme or with one of the better CLs (SBCL, etc.) over newLISP.

NewLISP is interesting for the space it occupies and it can be fun, but it also has some really wonky ideas that I think are mistakes and that will make it more difficult for you to grok other Lisps in the future. It is not a horrible language, but I think a person's time would be much better spent learning another Lisp. I would suggest that you Google comp.lang.lisp for newLISP. That should provide you with plenty of 'criticism' to digest. Several other people have asked the exact same question before on comp.lang.lisp.

Then, go to: <http://gigamonkeys.com/lispbox/> once you've moved on ;-)

<comment><AUTHOR> Thanks for the advice.

Actually I'm already studying Common Lisp (from the Practical common Lisp book), and, well, I really liked its concepts. And surely, it can be used for practical purposes. It's a different and old language, I believe it's worthy to be studied.

<comment><USER2> Cool.

PCL is a great book. And, yes, CL is incredibly practical for many purposes. PCL/CL are much more worthy of your time than newLISP.

</comment></comment></comment><comment><USER3> First and foremost, I think "newLISP" is an horrible name. What will they do when "newLISP" is 10 years old? Or maybe they don't expect it to survive that long?...

<comment><AUTHOR> Heh, actually it already reached that point, more than 10 years old I think.

From [http://www.softwarebyrob.com/2007/04/19/interview-with- lutz-...](http://www.softwarebyrob.com/2007/04/19/interview-with-lutz-mueller- creator-of-newlisp/)

"Lutz: newLISP started on SunBSD in the early 90's, then moved to Windows 3.0/1 as a 16-bit application, then to Windows 95/98 as a 32-bit program. During all that time newLISP was more like a hobby for me. Around 1999/2000 I made it Open-Source under the GPL license on Linux."

</comment></comment><comment><USER4> Depends on what you want it to do. Do you want to learn LISP or do you want newLISP to do a particular task? As a scripting language it does it's job very nice. I first started to use it when I needed a small, but flexible language that worked well on Windows. newLISP does the job just right.

A nice feature is the ability to compile a newLISP script to a standalone executable that does not require a newLISP interpreter. I hacked together a quick and dirsty script that my colleages at work like a lot - a script that cleans up crap in their windows profile directory. :-)

I have no experience with other LISPs though, and thus am not competent to say whether newLISP is a "true" LISP. To me that really does not matter - as long as the tool does the job.

Good luck.

</comment><comment><USER5> No gensym is an annoying decision to work around. Yeah you can hack it in, but...

If you want to use a lisp then choose the one with the most vitality, aka SBCL.</comment>


The Correspondent – Unbreaking news - <AUTHOR> https://thecorrespondent.com <comment><AUTHOR> The Correspondent is the international offspring of the Dutch news website with (almost) the same name, which has been pretty successful. It is purely member-funded, without any money from ads. They are currently having a membership rally.

They also have an interesting stance on the subjectivity of journalism: "At The Correspondent, we don't think journalists should pretend to be 'neutral' or 'unbiased'. Instead, our correspondents level with you about where they're coming from, in the belief that transparency about point-of-view is better than claiming to have none."</comment>


The US Military Is Creating the Future of Employee Monitoring - <AUTHOR> https://www.defenseone.com/technology/2019/03/us-military-creating-future-employee-monitoring/155824/?oref=d-river <comment><USER2> People who serve in the US military, or in jobs requiring DoD security clearance, already (and perhaps ironically) give up substantial US basic rights and privacy. The article sounds like this burden might be worsening.

We can appreciate those who sacrifice their rights for this reason, but that sacrifice can be a lot of ask of them, and of additional people who could also contribute. (Though, if we've been around some of the most selfish industry behavior too much lately, it might be hard to believe/remember that many people in other circles are motivated to serve by some kind of genuine altruism or sense of duty. But they exist.)

Personally, increasing burdens of invasiveness, including pressure to get clearance, are part of the reason that I decided to move back to non- government-related work. Though it's difficult to find dotcoms lately that give a warm-fuzzy sense of positive contribution that I got from a modest consulting role in public sector.

</comment><comment><USER3> Does this employee monitoring extend to -all- employees, or only to -some-?

Unless the employees being monitored include everybody, from Board members and C-level, all the way down to the janitor, and in some manner that information is open to all as well, then this is just more window dressing that'll be use to further stratify the workplace, allowing some to reap benefits of power at the expense of the majority.

But who am I kidding? I've yet to see an instance of a CEO being fired for failing a drug test...</comment>


Game Theory Reveals the Future of Deep Learning - <AUTHOR> https://medium.com/intuitionmachine/game-theory-maps-the-future-of-deep-learning-21e193b0e33a#.7v4y09kf4 <comment><USER2> Adversarial networks can be viewed as different agents competing against each other. But beyond that, I don't see how game theory is relevant or what insights it provides. This article is super vague and confusing to me.

>Where do these regularizations come from and how can we select a good regularization? How do we handle impartial information? This is where a game theoretic viewpoint becomes important. Generalization is sometimes referred to as 'structural risk minimization'.

Ok... and what useful insight do the game theorists have here? He doesn't elaborate at all. Regularization is a very well studied concept already. I don't see how this is connected to game theory at all. Regularization is all about priors and Occam's razor.

<comment><USER3> I believe that the key point here is that as adversarial networks compete against each other repeatedly they eventually will converge on a Nash Equilibrium.

Nash Equilibrium from Wikipedia: "Amy is making the best decision she can, taking into account Phil's decision while Phil's decision remains unchanged, and Phil is making the best decision he can, taking into account Amy's decision while Amy's decision remains unchanged."

At the point this happens, a stable solution exists which is almost like saying that we have made the most rational decision given the information we had. Nash was novel in this theory to say that if the participants were rational they would converge on an equilibrium and not get lost in endless recursion. Endless recursion being something like participants endlessly guessing the other opponent move... If Amy knows Phil knows Amy knows Phil knows Amy knows Phil... Obviously it would be problematic for DL to plunge into infinite recursion.

I like to think of the Nash Equilibrium as a balanced teeter totter. When the teeter totter becomes off balanced rational systems will relearn to balance the odds again based the properties of risk (what Nash referred to as utility I believe). Once they do so, they once again converge on an equilibrium.

<comment><USER4> The problem with statement "as adversarial networks compete against each other repeatedly they eventually will converge on a Nash Equilibrium" is that they often won't, and a big problem with training GANs is to ensure that they converge.

Intuitively, what can happen is that one of the problems is simpler to learn than another, and when one of the "players" becomes overwhelmingly good, then the other part of the network stops receiving useful feedback and is unable to find out a direction for improvement, the learning stops. A "sufficiently smart" method would be able to go to a Nash equilibrium even in this case, but current GAN methods can not, so you need to take steps to ensure that it doesn't happen - e.g. extra normalization or less training for the "simpler to learn" component.

It's not enough to train the "adversarial" networks to compete during each inference, on a meta-level you must ensure a form of cooperation to ensure that they are effective _teachers_ for each other during the learning process. For a real life analogy, there's a difference between effective behavior during combat and effective behavior during sparring.

<comment><USER3> Yeah, makes sense. It seems like when a network stops providing useful adversarial feedback that in and of itself is a learning experience for the smarter network. While it didn't reach an equilibrium it now knows it's at least smarter then the other guy. I feel like it should be able to use that experience of winning to beat the next guy.

It seems like for AI a perfect equilibrium wouldn't be easy to reach, its often hard for the human brain to reach one after all. It'd be the fact that an equilbrium exists though and that it's trained to find it that generates the knowledge along the way. Kinda like a journey not the destination learning method. I'm just theorizing though.

</comment></comment></comment></comment><comment><USER5> My background in game theory is from:

(1) careful study, teaching, and applying the detailed mathematics of linear programming and, in particular, its approach to proving the basic von Neumann saddle point theorem of game theory,

(2) applications of game theory to US strategic systems analysis, e.g., the _Blue_ side positioning submarines and targeting multi-warhead nuclear missiles and the _Red_ side allocating submarine search resources so that if Red shoots first Blue gets maximum expected target value destroyed,

(4) study of game theory from

Guillermo Owen, _Game Theory_ , W. B. Saunders.

(5) study of game theory, including Nash's result with a nice proof by Lemke and Sion's result, in

T. Parthasarathy and T. E. S. Raghavan, _Some Topics in Two-Person Games_ , ISBN 0-444-00059-3, American Elsevier.

With this background, I read the OP and found no clear connections with anything in _game theory_.

<comment><USER6> So is [1], for example, misleading?

[1] [https://arxiv.org/abs/1406.2661](https://arxiv.org/abs/1406.2661)

<comment><USER7> That paper doesn't mention game theory or the Nash equilibrium at all.

Perhaps you mean [2], which does. However, the article seems to misinterpret this: the fact that that system approximates the Nash equilibrium should be expected. Any system (including humans) that performs well in those types of games will, almost by definition.

[2] [https://arxiv.org/pdf/1603.01121.pdf](https://arxiv.org/pdf/1603.01121.pdf)

<comment><USER6> It doesn't mention Nash equilibrium, but the whole approach they are discussing comes from the idea of pitting two networks against each other in a "minimax two-player game".

"We propose a new framework for estimating generative models via an adversarial process, in which we simultaneously train two models ... This framework corresponds to a minimax two-player game."

Edit: Regarding the paper you linked to. The fact that a Nash equilibrium is expected is an important part of why it's interesting to structure things this way: it's an optimization process guaranteed to stabilize (whereas it's problematic that other approaches will diverge).

"When applied to Leduc poker, Neural Fictitious Self-Play (NFSP) approached a Nash equilibrium, whereas common reinforcement learning methods diverged"

<comment><USER7> I think we agree?

The articles claims (based on the paper I linked, and others) that:

 _What we see in these 3 players are 3 different ways game theory plays in Deep Learning. (1) As a means of describing and analyzing new DL architectures. (2) As a way to construct a learning strategy and (3) A way to predict behavior of human participants. The last application can make your skin crawl!_

Of these claims, I think all are wrong.

One can certainly make the case that it is interesting to measure the performance of a system compared to the Nash equilibrium (when possible), but the author seems to think that the designers of the system are somehow using game theory to design the system.

<comment><USER6> They are in one of the cases pointed out, not the other two. The novel idea is to have two networks compete against each other in a two-player minimax game, developing progressively better strategies until something like Nash equilibrium is reached--at which point you have one well-trained classifying network and one well-trained generating network.

</comment></comment></comment></comment></comment></comment><comment><USER8> The author is wildly extrapolating limited results ("Nash Equilibrium outcomes achieved by agents trained using deep reinforcement learning") to the entire field. Just because in DRL agents approach nash equilibrium in limited set of games does not means that somehow using nash equilibrium is going to help design future algorithms. E.g. for several games such as Pong, Go on which we know that DRL outperforms traditional methods, there is no tractable Nash equilibrium.

Also let alone so many other problem which come under umbrella of deep learning such as recognition / detection/ Seq to Sequence prediction where there is no "Game theory" component.

<comment><USER6> My understanding is that the use of game theory in this context has nothing to do with the domain in which the network is being trained. It's not about creating game playing AI's—it's about a 'game' between two neural networks, one who competes by getting better at classifying, and the other by getting better at generating. That basic architecture is quite general—which I think is why you also see e.g. LeCun being excited about this direction.

To be fair, the article does a kind of weird thing in discussing three different ways game theory has shown up in the context of machine learning recently—but they're all separate ideas really.

Edit: a more precise description in the abstract here: [https://arxiv.org/abs/1406.2661](https://arxiv.org/abs/1406.2661)

</comment></comment><comment><USER9> Game theory is a fun way to tell stories... but it is seldom predictive.

Conversely, machine learning seldom provides a story (at least in a human readable form) but it is predictive by nature.

<comment><USER10> Well here as are a few predictions made by game theory.

1\. There wasn't a nuclear war today

2\. Every telco in the world gives large chunks of money to governements due to auctions

3\. Ebay sellers get higher prices than they should

Also, I can read association rules, decision trees and lisp programs ok... and yet my machine learning programs (ok ok nowadays the ones I get out of various apis and packages) have written them...

<comment><USER11> 1 and 3 aren't predictions, but post-hoc explanations.

There is an argument that game theory helped lead to 1, I suppose. But, in general, I think that is giving them more credit than they would even ask for. Mutually assured destruction is far from their central theorem.

2 could just as easily be explained by standard supply/demand scenarios. There is a very limited supply of that is auctioned off to telcos and they have a very vested interest in buying as much as they can. Even if they are not going to utilize it.

<comment><USER10> What!!!

1) You can allocate credit how you like, but there's a dominant strategy for that too.

2)Ok for the UK case see

[http://www.nuff.ox.ac.uk/users/klemperer/biggestpaper.pdf](http://www.nuff.ox.ac.uk/users/klemperer/biggestpaper.pdf)

And look them up.

Interestingly your position makes me wonder if you are actually an exec working in a senior finance position in a major telco?

<comment><USER11> I'm looking forward reading that more in depth, but I am curious what you think my claim was.

I gladly admit I am using a layperson view that the spectrum auctioned off to telcos is a) likely to just get bought up by entrenched actors, and b) is unlikely to lead to any innovations in the marketplace.

Evidence that I am wrong on either of those points would be fun to read. My second claim, in particular, is one that I suspect is ill-founded.

<comment><USER12> EU economies auctioned off 3G spectrum at the same time. The ones with sloppily designed allocation rules raised far less money (controlling for GDP).

<comment><USER11> Yeah, that is what the linked paper was about. However, I'm not sure I care too much for the goal of raising more money. In some ways, I would view money raised as heat generated for a mechanism. That is, a necessary by product that is certain to correlate heavily with any outcome, but ultimately waste that should be minimized.

The cynic in me sees this as yet another way that economists have found to increase the wealth generation capabilities of valuable things, while at the same time losing sight of the utility that was there.

<comment><USER12> So the money either goes to government or the telcos' employees and shareholders. It's a valid goal for the government to attempt not to undersell the asset, but as you say it's primarily a transfer. If you want an example that changes more than market prices, have a look at Roth's work on matching for hospitals, schools and organs:

[https://www.google.co.uk/url?sa=t&source=web&rct=j&url=http:...](https://www.google.co.uk/url?sa=t&source=web&rct=j&url=http://www.nobelprize.org/nobel_prizes/economic- sciences/laureates/2012/popular- economicsciences2012.pdf&ved=0ahUKEwiylv-1gMnRAhXmJcAKHa-9DK0QFgg1MAI&usg=AFQjCNHR0sQAdtUdaxy6uJhd0np917-zpA&sig2=Z8UCv7AUPgB26C7tcEFIcA)

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER13> The Game Theory has nothing to say about partially observable, stochastic, continuous environments and has no concept of future.

<comment><USER14> > The Game Theory has nothing to say about partially observable, stochastic, > continuous environments and has no concept of future.

This is not true. What makes you think this way?

Game theory studies games with stochastic outcomes, adversaries, and partial observability. Bayesian Nash equilibrium, trembling hand equilibrium and correlated equilibrium are generalizations of Nash equilibrium into these domains. Game theory also extends to continuous environments and sequential games that have concept of past and future.

<comment><USER8> Whats is the Nash equilibrium of Pong? or Go? or Chess?

All the generalizations you cite are fancy economics methods which loose applicability at the first contact with complex real world scenarios.

Game Theory is like asking question such as "Is chess a win for white? [1]" Sure answering this question might be important theoretically but its of no use when designing an agent that plays and learns.

[1] [https://en.wikipedia.org/wiki/Solving_chess](https://en.wikipedia.org/wiki/Solving_chess)

<comment><USER15>
       loose applicability at the first contact

When thinking about complex domains, having a simplistic model is helpful for a variety of reasons, one of them is to establish a shared vocabulary to communicate with others, the other is to _study_ where/why/how the simplistic model fails to deal with the complex domain. This gives an indication for how to go on about dealing with the complex domain, namely by selectively making the simplistic model more complicated until it is sufficiently rich.

One example of the power of simplicity is the habit of theoretical computer scientists to use simplistic devices such as Turing machines as models of computing and to conflate "effective computability" with the complexity class P and polynomial reducibility (in LOGSPACE). We know that this 'looses applicability at the first contact with reality', but it's currently our only approach to have a meaningful theory of computational complexity and has lead to many deep insights already such as interactive proof systems and zero- knowledge proofs.

<comment><USER8> Hahahahaha reminds me of a saying about spherical cows.

If Game Theory was being used as an "explanation" to show why deep learning outperforms other methods then maybe it would have been fine. But then we already have Statistical Learning Theory and PAC learning which try to explain/prove bounds on Machine Learning models.

There is nothing wrong with having a theory but these days Deep Learning has become a bandwagon that any/everything gets related to. And I just don't see how Game Theory of all mathematical tools is applicable to Deep Learning.

Finally the misguided theory driven approach was exactly the reason why Deep Learning was so controversial initially. Turns out making a theory like SLT and deriving ML models like SVMs is a really bad idea. Deep Learning succeeded because the ML and Vision community adopted empiricism over the fanciest/longest proof with covex loss. So when someone goes around claiming Game Theory as a savior/future of Deep Learning I find it perplexing.

</comment></comment></comment></comment></comment><comment><USER16> I'm guessing a lot of you have read Neuromancer; I liken generative- adversarial networks to be a lot like neuromancer-wintermute networks :)

Imagine Robert Axelrod's iterated artificial intelligence agents tournaments [0], _reloaded_ ; let's pit GANs with LSTM cells, deep-q-networks, style- transferring networks, random forest algos, MCMC algorithms, word2vec architectures, etc. against one another, if only to see possible new failure modes of tit-for-tat.

[0] [https://en.wikipedia.org/wiki/Tit_for_tat#Background](https://en.wikipedia.org/wiki/Tit_for_tat#Background)

<comment><USER17> The second half of your post reads like word salad made from headlines about ML. They're all words, but the fact that you thought they form a thought with semantic content makes me worried. We need fewer MBAs coked out of their mind meddling with this stuff.

The advancements that are interesting in ML mostly come from deep statistics and information theory and very sophisticated analysis, not combining the most popular black boxes that you read a medium post about.

<comment><USER16> I think you might be over-fitting a bit with your model there

</comment></comment></comment><comment><USER18> One way to avoid overfitting is to trim spurious interactions Wij -> O. This constraint forces the network to economize on the neural circuitry, thereby driving the system to find an optimal network topology. Hypothetically this should favor certain circuit-design principles. I don't know how much work has been done in artificial neural networks but there has been quite a bit of work gone with artificial gene regulatory networks which utilize the same mathematical model of integrating weighted inputs and passing this through some kind of sigmoidal/logistic function.

</comment><comment><USER6> If you're curious what this is all about, I'd recommend jumping to this point in a video linked to in the article: [https://youtu.be/IbjF5VjniVE?t=42m11s](https://youtu.be/IbjF5VjniVE?t=42m11s) —Yann LeCun will begin saying, "the best idea ever ... is adversarial training."

The article is kind of confusing because it's discussing three different ways game theory has shown up in the context of machine learning recently—but they're all totally separate ideas.

</comment><comment><USER19> A lot of advances in deep learning have come from providing more data and semi-structured information, but there are a finite amount of fields for which this can apply. Using game theory dynamics can move AI to transfer of domain knowledge and can create more adaptable deep learning architectures. It could also be a pathway to "stronger" forms of AI.

</comment><comment><USER7> _and (3) A way to predict behavior of human participants. The last application can make your skin crawl!_

A lot of machine learning is about predicting human participants. Thing like "winning" at ImageNet have devolved into predicting the exact labels humans will put on a subset of the ImageNet dataset (as the "easy" labels are solved and it now comes down to working out what the most humans labelled confusing images as).

If that makes the authors skin crawl, one would have to wonder what they think ML actually is?

</comment><comment><USER20> Supervised learning - is learning from pairs of input -> desired output.

Unsupervised learning - is learning based on predicting future, present or past data from current data.

Both use immediate feedback.

Reinforcement learning is based on learning from dynamic datasets as opposed from static datasets.

Games are like dynamic datasets. Of course game theory has a lot to do with deep learning. If the signal you are learning is dynamic, it's related to game theory.

<comment><USER21> > If the signal you are learning is dynamic, it's related to game theory.

I'm not really familiar with the literature in this area, so sorry if this sounds dumb. But what you're saying here seems to make sense and sounds almost profound - like there's a vast amount of research (game theory) that's immediately related in some way. Is there somewhere I can read more about the relationship?

<comment><USER22> The references made in the article are probably the best place to start.

</comment></comment></comment><comment><USER23> I think the argument for using physics models for constraints in a DL system was a more clear argument [https://www.youtube.com/watch?v=5MdSE-N0bxs](https://www.youtube.com/watch?v=5MdSE-N0bxs)

</comment><comment><USER24> Computing Equilibria in Multi-Player Games - [http://theory.stanford.edu/~tim/papers/sym.pdf](http://theory.stanford.edu/~tim/papers/sym.pdf)

</comment><comment><USER25> the best explanation of this are Ian Goodfellow's talks (i think there are video transcripts online somewhere) or at NIPS this past year. He and a few others also have a new deep learning book just coming out this past month from MIT press

</comment><comment><USER26> This adversarial approach sounds a lot like evolutionary computation.

The idea of making Artificial Neural Networks compete with each other based on a selection function has been around for many years. I remember learning about it during my undergrad studies 6 years ago.

This just sounds like a more refined version of that. Using RNNs instead of ANNs.</comment>


Magic Leap announces largest C round in history - <AUTHOR> http://www.wired.com/2016/02/magic-leap-raises-the-biggest-a-round-in-venture-history/?mbid=social_twitter <comment><USER2> The Magic Leap team(s) directly responsible for the investor roadshow live demos must literally be delivering mind-blowing experiences for so many swathes of industry to be this excited.</comment>


Ask HN: Technical Programming/Science Podcasts? - <AUTHOR> Hey HN!
I would like to get into podcasts, and would be super interested in ones themed around programming and science.
However, everytime I do manage to find a podcast (on python or physics etc.) They always tend to be for the layman. I'd love a podcast for instance about python where each podcast was about very advanced programming topics or maybe highlighting a different library each podcast and discussing quirks and best practices. I just can't seem the find anything suitably technical, which makes sense since the medium isnt exactly great for it, but I'm sure there is some out there and I bet you guys know about them.
Feel free to plug your own technical/science podcast here, I'd love to listen! <comment><USER2> I just discovered Python Bytes. Every episode is a survey of a few interesting libraries or techniques. It's a casual listen for more experienced python folks. I've been doing python a long time and they almost always mention a library or topic I am not up to speed with.

</comment><comment><USER3> A science podcast you can try is Physics Frontiers. It gets pretty technical.

</comment><comment><USER4> Haven't seen any podcasts like that before. Maybe you can start one.

</comment><comment><USER5> Go Time is a great podcast if you are in to Golang

</comment><comment><USER6> Command Line Heroes comes to mind.</comment>


Features of SARS-CoV-2 Genome Suggest Sophisticated Laboratory Modification - <AUTHOR> https://zenodo.org/record/4028830 <comment><USER2> This paper is discussed on "This Week in Virology" ([https://www.microbe.tv/twiv/](https://www.microbe.tv/twiv/)) episode 664.

The paper is pure nonsense. Listen to virologist discuss it in detail.

Note that the doctor who is pushing this nonsense is connected to (and apparently funded by) two organizations connected to Steve Bannon. Why would Bannon care about pushing this nonsense?</comment>


How Many Words is Fair Use? Maybe More Than You and AP Thought - <AUTHOR> http://www.groklaw.net/article.php?story=20100922113406655

<comment><AUTHOR> My takeaway from this piece is that the Righthaven model of so-called "copyright trolling" depends on intimidation leading to pre-litigation settlements and will break down or stall if those who are targets of the intimidation just realize that they do have grounds to fight.

The problem remains, though, that for most people paying a few thousand as a nuisance payout is simpler and cheaper than going to the expense of a legal fight that will cost that much just for taking the first step or two.

The Righthaven model is disturbing to me not so much for its trolling aspects (and it does have those, since Righthaven will, in effect, scout out the terrain, find the offending pieces, and then approach the papers to get assignments on those items) as for its "collection agency" overtones: it is a business model built fundamentally on harassment of small players who more often than not have inadvertently stepped into it without even realizing what they were doing. This is _not_ a defense legally (see this piece for a lawyer- type analysis of why those sued are indeed often in the wrong under current copyright law: [http://www.patentlyo.com/patent/2010/09/zelnick-copyright- tr...](http://www.patentlyo.com/patent/2010/09/zelnick-copyright- trolls.html)), but it raises public policy concerns about whether copyright law should be so structured as to allow this. The law may say it's right but, as with collection-agency forms of abuse, it feels fundamentally unfair.

<comment><USER2> Can you suggest any paths leading to a solution?

If you make it more difficult to troll, you will probably encourage intentional infringement. Maybe a large expansion of compulsory licensing combined with some sort of universal liquidated damages paid into a common fund? I don't see any easy fixes.

Is copyright (and patent) trolling a greater or lesser problem in non-US countries? Is there something different in their systems that makes it this way, or are we just leading the curve by happenstance? Correspondingly, is infringement greater under other systems?

</comment></comment><comment><USER3> Seems unlikely that this case is going to set a precedent that redefines fair use in a jurisdiction that will be useful to you. Best not to copy whole articles in that case.

(That said, it is idiotic that you can sue someone for a copy of an article that a/ they did not post and b/ you never notified them of before suing them. THAT is broken. It should be illegal in general to utilize the courts for remedy before an equitable agreement is attempted outside the courts.)</comment>


Show HN: Hardware-agnostic library for near-term quantum machine learning - <AUTHOR> https://github.com/XanaduAI/pennylane <comment><AUTHOR> I'm one of the developers on PennyLane, a cross-platform Python library for quantum machine learning (QML), automatic differentiation, and optimization of hybrid quantum-classical computations.

For a while now, QML has been getting a _lot_ of hype --- at the Quantum2Business conference the other day, a quote that made the rounds was "QML: most overhyped and underestimated field at the same time" (attributed to Iordanis Kerenidis, I believe).

However, current research has been showing a lot of promise, especially as an application for near-term quantum devices, that doesn't require an exceptionally large number of fault tolerant qubits.

At the moment, the main approach to QML has been the so-called 'variational circuit' approach, where a parameterised quantum circuit is evaluated on quantum hardware, with optimization/machine learning then performed by an external classical ML library, such as TensorFlow/PyTorch. However, this is not the most optimal approach - the most optimal approach is to take advantage of the quantum hardware to also perform the optimization.

This was our goal with PennyLane. Before we could even start designing the library, we needed to know how to analytically evaluate gradients on quantum circuits; so we performed the research, discovered some cool analytic tricks, and published this separately [1]. This forms the backbone of PennyLane - <USER2> exact same quantum circuits used in the machine learning model are also used to calculate the gradient during backpropagation. As a result, you can construct arbitrarily complex classical-quantum models, with both the quantum and classical parts natively 'backpropagation aware'.

Even more ambitiously, we wanted an environment where you can build a hybrid classical-quantum computational model, using not only different quantum hardware devices at once, but different hardware devices _from different hardware vendors_. By taking advantage of _all_ near-term quantum hardware currently available - even those using fundamentally different models, such as qubits vs. photonic modes - you can build significantly more powerful computations. Currently, we have plugins available for [ProjectQ]([https://projectq.ch](https://projectq.ch)), [Strawberry Fields]([https://github.com/XanaduAI/strawberryfields](https://github.com/XanaduAI/strawberryfields)), [Qiskit]([https://qiskit.org/](https://qiskit.org/)), and more to come.

Feel free to ask any questions you might have on PennyLane, the state of QML, and quantum computation in general!

[1] Evaluating analytic gradients on quantum hardware ([https://arxiv.org/abs/1811.11184](https://arxiv.org/abs/1811.11184))

[2] Check out the PennyLane documentation for the nitty-gritty on our analytic gradient approach to QML: [https://pennylane.readthedocs.io](https://pennylane.readthedocs.io)

<comment><USER3> Is there any actual QC hardware that can run these algorithms? Does it even make sense to say that you can "run" code on a quantum computer?

I don't follow this field much, but I remember there was a company called D-Wave, and people saying their product was not a "real" quantum computer. Has anything changed since?

<comment><AUTHOR> Actually, yes! ML algorithms using PennyLane have been run on the IBM Q Experience, using both our Qiskit plugin ([https://github.com/carstenblank/pennylane- qiskit](https://github.com/carstenblank/pennylane-qiskit)) and our ProjectQ plugin ([https://github.com/xanaduai/pennylane- projectq](https://github.com/xanaduai/pennylane-projectq)).

I can't say much more at the moment, but we should have a few more plugins released in the next few weeks that targets hardware from other QC vendors.

The D-Wave question in an interesting one, though. Unlike the QC hardware available from IBM, Rigetti, Google, etc, which uses a universal circuit model, D-Wave has focused on a particular application - quantum annealing. While our theoretical quantum gradient results only apply to the qubit model, it is an interesting question whether they can be extended to the quantum annealing framework.

<comment><USER3> I looked at the intro page for Pennylane project, and it went completely over my head. I'm a ML person, can you tell me how can quantum computation help me, or why would I want to consider it? For example, would I be able to train my neural networks faster on a quantum computer? What's the point?</comment></comment></comment></comment>


Ask HN: Enterprise SaaS Pricing Models? - <AUTHOR> I'm looking for different pricing models by enterprise software companies like Atlassian's JIRA, SalesForce, etc to learn about methods they employ.
e.g, Free Tier, Cheap Tier, Discounts based on users etc.
Any good examples? <comment><USER2> At the enterprise level, almost always pricing information are "guidelines". They serve as anchors to the commercial negotiation stage. Often pricing is specific per customer. And heavily "discounted" based on various factors.

</comment><comment><USER3> [https://www.priceintelligently.com/blog/how-to-10x-your- saas...](https://www.priceintelligently.com/blog/how-to-10x-your-saas-prices)</comment>


Processing CoffeeScript Editor - <AUTHOR> http://pcsedit.appspot.com/

<comment><USER2> Hit ctrl+r (on a Mac) to toggle between the code and the visualization. Really cool, though a two-pane approach (code on the left, visualization on the right) would probably be more useful.</comment>