My Trouble with Bayes - <AUTHOR> http://themultidisciplinarian.com/2016/01/21/my-trouble-with-bayes/ <comment><USER2> If you consider subjective priors to be a problem, this can be addresses to some degree using so called "objective priors". They are objective in a sense that if two people agree on underlying principles of how priors should be assigned, then they will get the same priors. Catch is that you must decide what principles to use, as they are not objective themselves.

Updating multiple times on the same evidence can be bad - as it overstates evidence you have for some hypothesis - but you could do much worse. Instead of discovering that H implies E, suppose instead that you conditioned on H, which as later turned out is logically inconsistent. This is in general serious mistake regardless if what you are doing have word "frequentist" or "Bayes" attached to it, but consequences are not necessarily always the same. Larry Wasserman in chapter titled "Strengths and Weaknesses of Bayesian Inference" of his "All of Statistics" have an example concerned with estimating a normalizing constant. He compares the two approaches, frequentist one which works just fine, and Bayes one which fails miserably. There is no additional commentary so I always wondered if he never realized that derivation makes inconsistent assumptions, or he realized that but intended to show that frequentist comes out just fine. Ex falso quod libet.

Regarding the raven paradox, the underlying reasoning and conclusions always appeared to me to perfectly natural and reasonable. I think it is to great detriment for mathematics and statistics, that people come up with catch names with word "paradox" in it, for things that are merely unintuitive to them. For example Simpson's paradox is a simple observation that: probability of an event, is not a simple average of event probability across all groups, instead those within group event probabilities should be also weighted by relative group sizes. Whats paradoxical about that?

Regarding negation of H, not being a real hypothesis -- this is only true if you claim that you somehow consider all alternative hypotheses. I don't think people claim that. I seems to me that it is rather taken to represent only those alternative hypothesis that are under consideration given your modeling assumptions. Then it is perfectly fine and valid. I like how Jaynes avoided this kind of misinterpretations by conditioning everything on background information used and other assumptions. Let all of those be represented by B. Then you would talk about P(H|B) and P(~H|B), which makes it clearer that you don't talk all unknown unknowns.

</comment><comment><USER3> I have yet to see any convincing criticism of Bayesian reasoning when performed using priors derived from the Principle of Maximum Entropy [0]. By incorporating all information available and nothing more, such a prior neither makes unwarranted assumptions nor throws away information (as is very commonly done with other methods). In principle the process of generating such a prior demands absolutely no subjectivity, rather it it the result of a logical deduction from all information available. In practice some information may be difficult to specify or incorporate, however this is automatically accounted for by the Principle of Maximum Entropy as it guarantees that nothing is assumed that is unspecified and being unable to incorporate some information will merely result in all possibilities being considered without bias. In the very worst case when you have no relevant information which can be incorporated this regresses to an uninformative prior (such as the uniform distribution) which are easily and rigourously handled by this principle even in far more complex cases where other approaches fail entirely. Furthermore, given a different prior this process can tell you exactly what additional (unwarranted) assumptions are made.

Once the priors are specified, the actual process of Bayesian Reasoning is formal logical reasoning generalised to the case when you possess incomplete information. It tells you exactly the degree of belief you can assign to a proposition given some information; and given this information assigning either less or more belief than the precise amount this deductive process tells you are equally grave mistakes.

For further information on the Principle of Maximum Entropy I recommend reading Prior Probabilities (1968) [1] and chapters 11 and 12 of Probability Theory: The Logic of Science [2]. If you are unconvinced of the theoretical validity or universality of Bayesian reasoning I heartily recommend reading chapters 1 and 2 of Probability Theory: The Logic of Science [2].

[0]: [https://en.wikipedia.org/wiki/Principle_of_maximum_entropy](https://en.wikipedia.org/wiki/Principle_of_maximum_entropy) [1]: [http://bayes.wustl.edu/etj/articles/prior.pdf](http://bayes.wustl.edu/etj/articles/prior.pdf) [2]: [http://bayes.wustl.edu/etj/prob/book.pdf](http://bayes.wustl.edu/etj/prob/book.pdf)

</comment><comment><USER4> I'd like to point out that frequentist statistics suffer from just as many philosophical shenanigans. (For examples, see any introduction to Bayesian statistics.)

If you want "rationality", you're going to have to look elsewhere.

</comment><comment><USER5> _This is on everyone's short list of problems with Bayes. In the simplest interpretation of Bayes, old evidence has zero confirming power. If evidence E was on the books long ago and it suddenly comes to light that H entails E, no change in the value of H follows. This seems odd – to most outsiders anyway._

I don't understand what he's referring to here. If we now know that H entails E, then that means our model of the world changed, and thus our posterior on H changed as well. Did I miss anything?

It's an interesting article, but there is a lot of debate around the interpretation of Bayesian inference, and IMO there are answers to be found. In particular, Andrew Gelman argues against the subjective interpretation: [http://www.stat.columbia.edu/~gelman/research/published/phil...](http://www.stat.columbia.edu/~gelman/research/published/philosophy_online4.pdf) It's the best article I've read on the subject.

<comment><USER6> E was already known, and thus, taken into account.

</comment></comment><comment><USER7> So, he finds that intuitive guesstimates of probabilities are not very effective. No joke.

While probability is a really nice and useful theoretical construct, often in practice getting an accurate numerical estimate is from challenging to not doable.

Broadly there are three approaches:

(1) For something like coin flipping, just call it 1/2 and move on!

(2) There are stacks of theorems that can help, sometimes a lot. E.g., there is the renewal theorem that says that lots of stochastic arrival processes converge to Poisson processes, and there often in practice a good estimate of the arrival rate is easy and, then, a lot more probabilities just drop right out of various expressions for Poisson processes. Can also make use of the central limit theorem, the law of large numbers, the martingale inequality, a Markov assumption, etc. Here one of the best little tricks is to use intuition to justify independence (generally much more effective than using intuition in estimation of Bayes _priors_ ) and, then, exploit that assumption.

(3) Start with a Bayes _prior_ or whatever the heck but have an iterative scheme where can have several or many iterations and for that scheme have some solid theorems that the scheme converges. Then, iterate your way there.

<comment><USER8> Great post. Couldn't have said it any better myself. Point 3 is essential, IMHO. Superforecasting by Phillip Tetlock & Dan Gardner [1] relates an excellent description of this process in the realm of human forecasting even though they don't phrase it as a Bayesian approach. Essentially they found that those best able to predict world events continuously honed their estimates using an iterative process updating what really could be described as the priors of the superforcasters.

It's an enlightening read as they describe some of the processes used to hone intuited estimates using an outward and inward looking processes. I'm going to have to look into what you mean by using intuition to judge independence. Any good sources on that?

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

<comment><USER7> > I'm going to have to look into what you mean by using intuition to judge > independence. Any good sources on that?

If look at the relevant theorems, then will conclude that intuitively random variables X and Y are independent if and only if knowledge of one of them does nothing to tell you more about the other one.

If don't have independence, then can often have conditional independence, e.g., random variable X, Y are conditionally independent given Z implies

E[XY|Z] = E[X|Z] E[Y|Z]

So,

X = number of auto accidents today in LA

Y = number of auto accidents today in NY.

\</comment></comment></comment><comment>----

In a family with two children

X = gender of the first child

Y = gender of the second child

\</comment><comment>---

At a Web site

X = number of new user sessions from 10:00 AM to 10:01 AM

Y = number of new user sessions from 10:01 AM to 10:02 AM

\</comment><comment>-----

On a commercial airline flight

X = height of the first passenger to buy a ticket

Y = height of the 10th passenger to buy a ticket

Etc. Just intuition from knowledge of one of these two tells you nothing more about the other one (we assume we know the two distributions -- that we get insight into a distribution doesn't count).\

Then using independence and very little more, can use the main limit theorems, law of large numbers, central limit theorem, etc.

If don't have independence, then sometimes can fake it: Given a list of n phone numbers, if toss them into a bucket and stir it and pull out the numbers and label them as X_1, X_2, ..., then in common situations can assume that the X's are independent.

There are tests for independence. Likely the first to know about is a chi- squared test on a table of values of the two variables.

</comment><comment><USER9> It seems like most of these complaints center around the idea of the inherent subjectivity of the prior. In cases like astronomy and other hard sciences, the prior reflects actual scientific knowledge and is not really subjective at all. In cases where we don't have that kind of evidence, empirical Bayes methods work very well by just peaking at some subset of the data and finding a good point estimate for the prior.

I'm also not sure why the OP thinks that calculating the normalizing constant is a huge issue. Most of the time you rarely need it since you're likely going to end up doing an MCMC or some other sampling method for the posterior, in which case you only need proportionality.

There are lots of problems with Bayesian methods in practice, but most of them revolve around the scalability of modern methods to massive data sets and very complicated models. Many Bayesians tend to think that it's absolutely crucial to quantify uncertainty and that the added computational cost and human effort is worthwhile. In practice, point estimate methods to find MAP or even just maximum likelihood values work really well for most problems. If you look at the trend in most machine learning, for instance, generally people find a cool way to solve some problem with good performance (e.g. SGD + Deep Nets), then some Bayesian lab spends a few years trying to interpret everything as a generative model and coming up with a clever way to sample everything (e.g. Lawernce Carin's lab at Duke has done a lot of this work in Deep Bayesian Nets). The end result is usually better, but by then most people have moved on to a newer problem and the appeal of getting a marginal boost in performance is harder for me to see. The Bayesian nonparametrics crowd has historically done a pretty good job of hitting a sweet spot of compromise on this by keeping a Bayesian view but still (usually) treating everything as an optimization problem first (e.g. variational inference methods).

<comment><USER10> It seems like your attitude towards statistical errors is largely going to depend on the risk of making bad predictions.

For example, the problem with the denominator containing "unknown unknowns" isn't much of an issue if you're searching photographs or optimizing ad revenue. It's much more important for something safety-related like building an airplane or a driverless car.

Finance is in the middle: not directly safety related, but modeling tail risk the wrong way could bankrupt the company.

</comment></comment><comment> indiana-b I do not understand the problem people have with priors in Bayesian methodology. Yes, it is true that a poor choice of prior can affect results. But classical, frequentist techniques incorporate priors implicitly: a flat prior indicating we have no information other than the data. And just as a poor Bayesian prior based on subjective belief can ruin an analysis, a non informative prior implicitly made can be just as catastrophic. And it is truly a rare case when there is absolutely nothing known about a process, and in these cases, a flat prior _is_ the kind of poor prior that these people are so afraid of.

<comment><USER11> Right. All human endeavor involves subjectivity in some fashion, Bayesian thinking just lets you quantify it and handle it explicitly.

<comment><USER6> I believe this is a contradiction. How do you quantify subjectivity?

<comment><USER12> Let's start with something lighter: how do you categorize subjective states of mind? But we do through words like "happy", "sad", "good-will". Additionally we can make statements as to the degree of sadness, or degree of happiness. Psychologists do this professionally with their survey instruments, but even the layman is capable of saying "I was most happy at my wedding and least happy at my great-grandfather's funeral", which sets bounds with two points of reference.

Oops! Anything with degrees of effect and bounds is basically a finite ordering. And a finite ordering can be given a rank, with numbers. So now we have given numbers to subjective states.

This is obviously quite handwavy, but the core ideas are here. I might be missing something. The big differences are that probability assigns a continuous measure to what we believe is Belief. How do you get an infinite, uncountable number of experiences?

One way is to have the acceptable accuracy be less than an infinite number of digits. That's always going to happen in practice but it's not quite what we're looking for. One other way to do it is to use preferences and expected value. Do you think your knowledge is complete enough such that you'd be indifferent to betting an X amount of money on a roullette wheel with given probability of winning P? Then P is your degree of belief.

In the end there are very good reasons to doubt subjective probability estimates. But as long as one works with bounds and acceptable degrees of error, then you at least get a sense of how it is you're going wrong.

<comment><USER6> You can maybe gain some sense, but I'm not sure if it can exactly tell you how you're going wrong (except possibly to say, " _if_ you believe these things, it makes no sense to also believe this other thing"; where a thing is a probability value assignment -- the danger is in believing that such analysis can give you positive knowledge [for instance, "I believe these things, so this other things _must_ be the case"). I believe you need a total ordering, not just a finite, partial ordering. Maybe you can say wedding is good, funeral is bad, but how would you incorporate something like the birth of a child, the taste of some food, etc? Basically, you have to reduce all aspects of subjectivity to an integer, which could very well be impossible (making the activity of trying to turn subjectivity into integers highly suspect).

I understand that economic games sometimes use degree of belief, but in the example of a roulette wheel, we can actually count up all of the possibilities and assign numbers based on that. I don't think we can count all of the possible subjective states.

>How do you get an infinite, uncountable number of experiences?

I experience this all the time (though I can't say they are infinite, it is certainly more than I can count).

<comment><USER12> I lost my reply because the site went down! I'll give a brief one here.

> integers

Or a matrix. Or with some dimension but not others. A total ranking is implausible and lossy, but partial rankings for some traits is tractable: you just have to be careful. If motivated by a decision the use of probability becomes more clear, since you can declare what kinds of errors you can handle and what you can't, relative to the information that you specifically want from an event.

> positive information

This is a problem with statistics, not Bayes. Null hypothesis testing with its p-values and t-tests can only reject a known distribution, not telling you the real distribution without testing for all of them. At that point it can be as prone to GIGO as Bayesian methods are.

There are some statisticians who dissolve the whole Bayes vs Not debate by focusing on the optimisation of loss functions. Although it lacks the philosophical pyrotechnics of subjective probability, in practice it's probably the most reasonable approach: do what works.</comment></comment></comment></comment></comment></comment>


Professional Hacks: Tricks of the Trade - <AUTHOR> http://www.themorningnews.org/archives/how_to/tricks_of_the_trade.php <comment><USER2> This post was the precursor for <http://www.tradetricks.org/>, which used to publish user-submitted tricks every day. Start here and click through:

<http://www.tradetricks.org/archives/001915.html>

(I can't find an index page.)

</comment><comment><USER3> FTA: "...the gap between software engineers and birthday clowns is almost negligible."

True.

</comment><comment><USER4> _"... Mapmakers will often use "copyright traps," bits of information in their maps that are purposefully wrong ..."_

Very true. I once had to re-do a map for this exact reason though I'm not sure the _"purposeful"_ fit was to get the major intersection on the page or to catch people out.

 _"... In Australia, the butchers have a secret language called "rechtub klat" ..."_

keew txen tuo siht yrt ot gniog.

<comment><USER5> From the article it appears that in "rechtub klat" the letters in a word are reversed, but the words have the same order in the sentence. So it would be:

      "gniog ot yrt siht tuo txen keew"

<comment><USER6> He probably just did a str.reverse instead of str.split(' ').map {|w| w.reverse}.join ' '

<comment><USER4> _"... He probably just did a str.reverse instead of str.split(' ').map {|w| w.reverse}.join ' ' ..."_

Nothing so elaborate, just in my head.

</comment></comment></comment></comment><comment><AUTHOR> Heh, I started measuring my fingers after reading this. It's kind of mind boggling how symmetrical your left and right hand are.

</comment><comment><USER7> This is a great article and where I got the inspiration for the term Acting Sober: [http://blog.figuringshitout.com/oct-28th-day-16-acting- sober...](http://blog.figuringshitout.com/oct-28th-day-16-acting-sober/)

<comment><USER8> I know it's not quite the same thing, but I have a t-shirt (from an Irish pub) that has the great W.B. Yeats quote:

"The problem with some people is that when they aren't drunk, they're sober."

</comment></comment><comment><USER9> _"and I'm thinking of incorporating some XML functionality"_ \- is it still 1999? =)

<comment><USER2> "Published August 24, 2004"

<comment><USER10> The updated example would be "incorporating Cloud API".

<comment><USER11> Or "rewriting the whole thing in Rails, using agile development practices, of course."

<comment><USER8> That's a couple of years out of date. These days it would be more like "server-side doesn't matter, we use jquery on the front end to build a rich front end without proprietary products." Though, since I've actually said that myself, I'm not willing to admit that's a trick yet.</comment></comment></comment></comment></comment>


Yelp Dataset Challenge Is Doubling Up - <AUTHOR> http://engineeringblog.yelp.com/2015/02/yelp-dataset-challenge-is-doubling-up.html

<comment><AUTHOR> Two years, four highly competitive rounds, over $35,000 in cash prizes awarded and several hundred peer-reviewed papers later: the Yelp Dataset Challenge is doubling up. We are proud to announce our latest dataset that includes information about local businesses in 10 cities across 4 countries. This dataset contains 1.6M reviews and 500K tips by 366K users for 61K businesses along with rich attributes data (such as hours of operation, ambience, parking availability) for these businesses, social network information about the users, as well as aggregated check-ins over time for all these users. This treasure trove of local business data is waiting to be mined and we can't wait to see you push the frontiers of data science research with our data. Submit your Data Science project by June 30, 2015 to win one of several prizes.</comment>


Tell HN: YouTube music no longer supports Mozilla Firefox - <AUTHOR> Going to https://music.youtube.com/ on Mozilla Firfox gives the following message:<p>Sorry, YouTube Music is not optimized for your browser. Check for updates or try Google Chrome. <comment><USER2> It might be a version check. I'm using Firefox 68.10.0 on Android and YouTube Music works just fine

</comment><comment><USER3> MacOSX Catalina 10.15.5 Firefox Developer Edition 78.0b9

working perfectly.

</comment><comment><USER4> Firefox 79.0b3 (64-bit) on Ubuntu 19.10 works

</comment><comment> t-writescode Windows Firefox 78.0.1 works fine.

I can check Linux later

</comment><comment><USER5> iOS Version 27.0 (18428) - works perfectly fine here

</comment><comment><USER6> Works on my machine.</comment>


How to Write a Great RFP (Request for Proposal)? - <AUTHOR> https://easternpeak.com/blog/mobile-app-rfp/?utm_source=ycomb&utm_medium=post&utm_campaign=rfp <comment><USER2> Here is a must read whitepaper on similar thing : Reinventing the RFP: Getting the Most Out of Your Document Review Platform in 2016…and Beyond?

[http://document-management- systems.cioreview.com/whitepaper/...](http://document-management- systems.cioreview.com/whitepaper/rfp-request-for-proposal-get-most-out-of- your-document-review-platform-wid-241.html)</comment>


How Apple lost $3000 trying to extort extra $4 from a returning customer - <AUTHOR> https://medium.com/@srdjankovacevic/how-apple-lost-over-3000-trying-to-extort-extra-4-from-a-returning-customer-b00e34e0ea09

<comment><USER2> I've made a product under the Apple MFi program and let me tell you the people that are making uncertified cables and accessories likely are doing a lot more than "not paying the license fee to Apple." Unless you are in China bribing someone to sell you stolen IP I can't imagine how you would produce a knock off cable. The lighting connectors and auth chips are _really_ tightly controlled.

Plus, it's doubtful that any of the rigorous certification testing takes place on these knockoffs and the spec is really easy to get wrong. So yeah, I've got no sympathy for this guy at all.

</comment><comment><USER3> I actually don't see a problem with Apple's MFi program. Back in 2013, a woman in China was electrocuted by her iPhone 4 due to a non-OEM charger:

[http://www.scmp.com/news/china/article/1283818/woman- electro...](http://www.scmp.com/news/china/article/1283818/woman-electrocuted- while-answering-iphone-may-have-been-using-fake?page=all)

To quote from the article: "Knockoff chargers sometimes cut corners," Xiang said. "The quality of the capacitor and circuit protector may not be good, and this may lead to the capacitor breaking down and sending 220 volts of electricity directly into the cell phone battery."

Apple trying to enforce its quality standards on the charging system seems completely reasonable -- yes, even if it means that the end-user has to pay for the quality. Most Apple customers are actually looking for that quality and willing to pay for it.

There is a great teardown analysis of Apple and knock-off chargers at Ken Shirriff's blog:

[http://www.righto.com/2014/05/a-look-inside-ipad-chargers- pr...](http://www.righto.com/2014/05/a-look-inside-ipad-chargers-pricey.html)

[http://www.righto.com/2012/05/apple-iphone-charger- teardown-...](http://www.righto.com/2012/05/apple-iphone-charger-teardown- quality.html)

</comment><comment><USER4> Anecdotes are not data but I've got plenty of mileage from Lightning cables bought from the local Poundland - since they cost £1, I'm more than reasonably sure they're not paying the $4 license fee for MFi.

Sounds more likely that his cheap cable broke (as they do) and just plain didn't work any more.

<comment><AUTHOR> Source: [http://www.mobileburn.com/22031/news/ios-7-blocks- uncertifie...](http://www.mobileburn.com/22031/news/ios-7-blocks-uncertified- lightning-cables-but-theres-a-way-to-bypass-it)

<comment><USER4> I've had every Lightning-enabled iPhone (bar the 6+) and iPod since their introduction and I've never experienced this problem with unlicensed cables. But trading anecdata is going to get us nowhere...

</comment></comment></comment><comment><USER5> why does walmart occasionally pay $100,000 in an injury lawsuit from tacking a shoplifter who stole $10 of stuff? because the accumulative effects of doing nothing will cost far more than $100,000

</comment><comment><USER6> Does it actually not charge, or just warn that it might not work reliably?</comment>


One Final Effort - <AUTHOR> http://halo.bungie.net/news/content.aspx?cid=25650 <comment><AUTHOR> "Earlier this week, we asked the team to take some time out to send along their thoughts on Halo 2's development process. You'll find a selection of their unfiltered memories below – some good and some bad. Attached, you'll also find a discussion thread. We'd love it if you'd leave some of your own favorite Halo 2 memories for posterity, whether it was waiting in line for launch, firing up Halo 2 for the first time, or Battle Rifling a hole into our faces during a Humpday Challenge."

Really brutal honest look at the nasty parts of the game industry.</comment>


'Moment of reckoning': US cities burn recyclables after China bans imports - <AUTHOR> https://www.theguardian.com/cities/2019/feb/21/philadelphia-covanta-incinerator-recyclables-china-ban-imports <comment><USER2> I've always wondered why there couldn't be standard containers for products like jam, wine, butter etc. where the containers are designed to be easily washed and reused. Manufacturers could still create their own branded containers but would pay more somehow for doing so. Is there an obvious problem with this idea?

It's nuts that if you buy e.g. 4 bottles of wine they all have different bottle designs and if you optionally go through the effort of recycling them there might be some process involved where they're sent to another country, broken down, melted and then reformed it into new bottles at best. Just wash and reuse the bottle...?

<comment><USER3> This is commonly done with bottled water in many European countries. You see stacks of formed plastic holders for the bottles in the back. As bottles get drunk, the empties are placed back into the holders, and the company servicing the restaurant comes frequently and swaps out the empties for full ones. You can tell the bottles are reused a lot because they have pretty substantial wear marks on their sides where they rub against the holders.

And yeah, it'd be great if the same kind of system were extended to more products in the US. It'd be awesome if we could standardize on containers of, e.g., size 50mL, 100mL, 200mL, 500mL, 1 L, both for liquid and solid goods, and just have everything be sold in those. Then you'd just recycle those containers as normal, and instead of being broken down and remade, they'd simply be washed and reused.

<comment><USER4> It's not done for small bottled water in the US, but it is done for multi- gallon "water bottles", i.e. the things you use with a water cooler. Mostly you're not returning them, though (although you _can_ return them); you're just reusing the ones you own.

I feel like that might be a more sustainable system: a grocery store where everything is shipped to the store and held in large bulk containers (which can be reused between the store and the supplier), and then, when purchased (through a deli counter or machines), some of the contents of the large container are transferred to fill up a small reusable plastic container you've brought from home. (Either by plugging it into the vending machine—like with refillable water jugs—or by handing it to the deli clerk to fill. Or, in the case of bulk bins, just filling your containers yourself, and then weighing them at the self-checkout. [That presumes each container has some sort of standardized tare code on it you can scan so that you don't have to weigh every container empty when you first come in.])

<comment><USER5> Such grocery stores exist: [https://www.theguardian.com/sustainable- business/2014/sep/16...](https://www.theguardian.com/sustainable- business/2014/sep/16/berlin-duo-supermarket-no-packaging-food-waste)

</comment></comment></comment></comment><comment><USER6> > too difficult

> impossible

These words are funny to me. It's not literally "too difficult" or "impossible" for people to sort their recyclables. I think they essentially mean, we don't know how to make people do this, or we think we'll be voted out if we ask people to do it. And what it boils down to is that, it's not a socially accepted/expected practice to sort your recyclables. But, you know what? That is a completely different thing from being "too difficult" or "impossible". And by conflating those two things, we as a society are operating with blinders on.

As a thought experiment, imagine everybody else was making the needed compromises (to their time, space, etc.) to properly sort recyclables. Is it still impossible for you?

<comment><USER7> IMO, you shouldn't ask people to sort recyclable materials at home for a few reasons:

1\. It's not impossible, but it's _impractical_. You need multiple containers all of a sudden, and these can't be fixed-size containers because not everyone consumes the same proportion of any given material.

2\. People are going to sort things wrong, meaning you need to check/re-sort at the processing plant.

3\. How difficult of a challenge is it to build sorting machines, anyway? Are you going to tell me self-driving cars are coming soon but we can't build machines to handle this? If it really is too hard, have regulations put in place so that some machine-readable material tag be put on all packaging.

4\. I think this is a good domain for regulators to step in. Tax things that are hard to recycle, and encourage packaging that is easy to recycle or biodegradable. Keep in mind, glass containers are recyclable and also _reusable_ , meaning you can just clean and refill them at the factory, which is more energy-efficient than melting everything. No new technology needed, just go back to selling milk, sodas, etc. in glass jugs.

<comment><USER8> > How difficult of a challenge is it to build sorting machines, anyway?

Machine vision and learning, conveyor belts, lots of delta arms - seems doable to me.

Heck - maybe we need something akin to the whole "smart car" thing in China - let kids and others come up with trash sorting machines, compete in challenges (FIRST/FRC style?), etc?

Hmm - business idea:

Educational STEM startup focused on the above (aka - FIRST/FRC robot contests for trash sorting); all entries must be open source/open hardware; same company (more or less) could use innovations from the open source entries to develop full-scale machines and systems for implementation in actual industry?

<comment><USER9> If it's already contaminated, with food waste or other, there's no amount of machine vision or labour that will get you rid of the contamination so you can send it to China.

<comment><USER10> maybe you use the machine vision and sorting machine to reject that item then, and still send all the uncontaminated items to China?

<comment><USER11> Years ago I dabbled in the agtech space and reasonably affordable spectrometers were available. Perhaps that could help pick out contaminated items?

</comment></comment></comment></comment></comment></comment><comment><USER12> I've long maintained that plastics recycling is worse than useless -- washing all of that plastic takes loads of water, and there just aren't many uses for recycled plastic. Consider the plastics around you. How many objects are virgin plastic? How many are recycled? There's not some secret destination for recycled plastics. Clearly it's being dumped or burned, and it has been for a long time. Now we're doing it in the U.S. again, it's much harder to pretend that's not its fate.

<comment><USER3> If the plastic is burned in a really high quality incinerator, with a great scrubber stack, it at least isn't putting out lots of pollutants, and can generate power to boot. This might be a better fate than having them end up in a landfill, though of course they are releasing CO2 when you burn them (though I don't know if that's significant at all compared to global CO2 released in manufacturing and transport).

<comment><USER13> About the same CO2 impact as manufacturing them.

The problem is burning it clean. To do that you have to run a very hot furnace, near gasification temperatures.

Otherwise, you will be releasing cracked chlorine, sulphate, partial urethane chains and other hydrocarbons into air. They're invisible but noxious and sometimes stinky.

Electroscrubbers have limitations and high energy cost too.

</comment></comment></comment><comment><USER14> Whenever I see stories revolving around this sort of thing, I'm always reminded of the Penn & Teller: Bullshit! episode they did on recycling ([https://www.imdb.com/title/tt0771119/](https://www.imdb.com/title/tt0771119/)). They argue that landfills really aren't that bad and may actually be better than recycling. Of course the entire _premise_ of that show was that you shouldn't just blindly believe everything you're told -- INCLUDING what the show itself tries to argue for. So I have no idea how valid any of their argument actually is.

<comment><USER15> If I recall their entire argument was based on whether or not something _financially_ worth it. And so they recommended recycling aluminum, because aluminum is worth so much. Whereas everything else loses money.

If it were true that recycling plastic were better for the environment, but was a financial loss I'd be for it. I'm not sure this is true, but the point is that purely financial considerations miss the bigger picture here.

As other HN posters have pointed out, it seems that fewer disposable plastic containers is the better path here. (really, as few as possible!)

<comment><USER4> Consider: it might be cheaper in total long-term ROI to dispose of things in landfill now, and then let people a hundred years from now dig them back up if they have need for the materials then, than to recycle those things right now. And by "cheaper", I mean for the entire economy that includes both us and the hypothetical future people digging those things up! Our recycling now might have lower ROI (higher costs, less reclamation efficiency) than their digging- up + recycling would! (This is actually a thing in archaeology: frequently sites that are hard to dig up will be left to future archaeologists who—it is assumed—will be able to reclaim them more cheaply and effectively than we can today.)

It's sort of like the "bargain" of cryptocurrencies: what promotes long-term GDP growth more, bank fees or massive electricity use? Crypto miners are hurting the environment right now; but they pay for their own externalities. Banks impose fees that lower net productivity in a way that might mean that the companies/technologies that we need to reach sustainability take longer to come into existence. So will we be in a better place with 100 years of crypto mining + 100 years of an economy [including green industry] that was spurred on no bank fees; or vice versa? The question doesn't have an immediate, intuitive answer.

A stupid but weirdly-precise analogy: when playing an RTS like Starcraft, anything that slows down your "economy" (mineral mining) prevents you from "teching up" as quickly as your opponent. In humanity's case, our opponent is Malthusian resource starvation (in the small—of individual resources) and habitat loss from climate change. Anything that slows down our economy from "teching up" to face these problems, for a reward of merely _moving around in time_ our ability to use our resources (rather than decreasing permanent losses/increasing permanent gains of resources), isn't really worth it, if we're "racing the clock." (That's a big, hotly-debated "if", of course.)

<comment><USER16> > what promotes long-term GDP growth more, bank fees or massive electricity > use?

Assuming they have the same cost, bank fees promote more GDP growth, hands down, at any time horizon.

Money simply changing hands will always beat money changing hands with added useless usage of resources and labor.

And that's not even considering the reality, that average electricity costs of a BTC transaction are orders of magnitude expensive than the average bank fees on money transactions.

<comment><USER4> Oh, no, I meant that the other way around. As in, "what promotes GDP growth more—companies and individuals having more money from a [lack of] bank fees, or power grids having more spare capacity from a lack of miners consuming electricity"?

</comment></comment></comment></comment></comment><comment><USER17> Could we make standardized durable containers that can simply be scrubbed, optionally polished and reused? Or just melted down and reused. Seemed to work ok for the dairy industry decades before my birth.

<comment><USER18> That's the amazing thing about what the developed world right now, recycling is the _worst_ of the three things we should be doing. i.e.

Reduce. Reuse. Recycle.

Go to a developing country and the deposit on the beer bottle costs more than the beer in it. They are all clean and reused. Tons of countries charge money for plastic bags, or have even made them illegal. We need to catch up.

<comment><USER19> Do you think the rest of the world is ready for milk in bags?

And most other non-carbonated liquids?

<comment><USER20> Why would you use a plastic bag for milk? Most of the milk I buy comes in paper cartons.[1] Paper should degrade much faster than a plastic bag, plastic bottle, or glass.

[1][https://www.horizon.com/faqs?f%5B5%5D=field_faq_category%3A9...](https://www.horizon.com/faqs?f%5B5%5D=field_faq_category%3A98)

<comment><USER21> The inside of that carton is still lined with plastic tho.

<comment><USER20> 24% polyethylene is still much better than a near 100% plastic bag or milk container.

<comment><USER22> It depends. If your county has the right equipment to recycle those mixed paper/plastic cartons then probably so, otherwise the whole thing goes into landfill or is incinerated, and that's more material than a plastic bag. You can check online if your county has the facility (unfortunately mine doesn't).

</comment></comment></comment></comment></comment></comment></comment><comment><USER23> This is super exciting. One of the grand challenges I've been thinking about is tackling waste. Why is any material considered waste? The first principles approach to this problem says that landfills are mountains of energy and diverse resources waiting to be tapped.

The first step though is to ignore the pervailing reclamation, recycling mentality at the macro level and begin the gruelling work of building a new ecology. We're at a point now where concerted effort into engineered (or found through directed evolution) organisms gives us the opportunity to break down and then re-integrate these dormant resources.

In the future a 'recycling' plant will accept any and all waste and be the front end of a manufacturing hub that outputs both new raw materials and finished products. In between the two ends it will be biotechnology that enables the transition from waste back to usable component resources.

<comment><USER24> > landfills are mountains of energy

If you're talking about literally turning garbage into fuel, there's, as I understand it, very rapidly diminishing returns unfortunately.

Even the apparently simple act of just burning garbage to generate electricity is complex, because you have to be concerned about what the heck is in there and what you're releasing into the air.

<comment><USER25> In principle, plasma gasification _can_ be made to work net positive energy output, plus slag for whatever you want to use slag for.

In practice, it's really expensive to set up and operate without a lot of throughput, so it doesn't happen that much.

Though, I've read the US Navy is putting plasma gasifiers onto its newest generations of big ships.

<comment><USER26> I asked a local waste handling company owner whether he'd be interested in plasma gasification. He told me that one plasma gasification plant would require all the trash from Vermont, plus parts of NY and NH and MA to keep it fed and economical. So that would require a lot of trucking. Still, that seems better than releasing all the toxins in the materials into the environment and means just one plant could service a large rural area. More plants would be needed in more densely populated areas. Still seems like a great solution.

</comment></comment></comment></comment><comment><USER27> A large part of this is the new rules on contamination that exclude a lot of material. 0.5% is China's new limit, while a average city with curbside collection could never meet that. Think about your typical recycling bin: You put in some newspaper that is prime recycling material, but then a milk jug or soda bottle that hasn't been fully emptied or rinsed gets tossed in and the paper gets soaked and is now unusable for recycling. Same with pizza boxes that have grease, stuff that gets rained on, people putting stuff in the bins that isn't recyclable in this manner (including electronic components and such [0]), and suddenly you're throwing away (or burning) a huge amount of material.

"China, once the biggest single processor of recycling, said in the spring that it would no longer accept loads of recyclable items — such as plastic, glass, cardboard, and metals — that were more than 0.5 percent contaminated. Officials said they were trying to cut down on pollution from processing dirty recyclables.

Philadelphia's contamination rate is anywhere from 15 percent to 20 percent. That meant its previous contractor for recycling, Republic Services, had to find other markets for processing or begin disposing of portions of contaminated loads in other ways, such as in landfills or by incineration.

As recently as the first quarter of 2012, Philadelphia was getting paid $67.35 a ton for its recyclables. By summer 2018, Republic was negotiating a new contract to process recyclables that would cost the city $170 a ton."[1]

[0] "Reduce, reuse, incinerate: Why half of Philly's recyclables aren't recycled" (Feb 11, 2019) [https://www.npr.org/podcasts/657780675/the- why](https://www.npr.org/podcasts/657780675/the-why)

[1] "At least half of Philly's recycling goes straight to an incinerator" (Jan 25 2019) [https://www.philly.com/science/climate/recycling-costs- phila...](https://www.philly.com/science/climate/recycling-costs-philadelphia- incinerator-waste-to-energy-plant-20190125.html)

</comment><comment><USER28> Okay, serious question: how much carbon is sequestered in plastic if we toss it in a landfill? Given that there's a finite amount of oil left in the world, and that it gets more expensive as supplies dwindle, I almost wonder if using more disposable plastics _helps_ the fight against climate change. Better to turn the carbon into a solid and bury it than burn it and put the CO2 in the atmosphere, right?

<comment><USER29> Not a direct answer, but 4% of global oil production goes to plastics, so I'd put the ceiling slightly higher.

<comment><USER30> 4% does not seem a big enough slice of the carbon puzzle pie to really make a huge difference compared to something like fuels. seems like we should just focus on a solution that minimizes local and immediate human suffering.

</comment></comment></comment><comment><USER31> Another good article on the topic:

China's Import Ban Broke Plastic Recycling. Here's How to Fix It

[https://news.nationalgeographic.com/2018/06/china-plastic- re...](https://news.nationalgeographic.com/2018/06/china-plastic-recycling- ban-solutions-science-environment/)

</comment><comment><USER32> Fully aware that it's not a globally useful solution, but I am surprised there aren't alternatives to China for trash dumping. Why aren't there alternatives. I refuse to believe all other countries are so eco-minded that they wouldn't take a dirty cash grab

<comment><USER33> Going on pieces I've read in the last few months, others are backing away from being the world's recyclers too.

I recall a piece about Malaysia no longer being willing to thanks to a large increase in localised pollution, and illegal burning of non-recyclables (wrong plastic in bundle, labels, lids, etc). A fast search doesn't turn up a link.

<comment><USER19> They might also realize they can get the same inputs by creating domestic recycling programs.

</comment></comment></comment><comment><USER34> Relevant: 99pi recently had an episode on China banning imports of recyclables - [https://99percentinvisible.org/episode/national- sword/](https://99percentinvisible.org/episode/national-sword/)

</comment><comment><USER35> It seems like we need better education and publicity campaigns. It should always be easy to look up the local rules. People should feel like it's more important to keep the recycling stream clean than it is to recycle at all, which is the opposite of what they do today where putting more stuff in the recycling bin is somehow thought to be better even if it doesn't follow the rules.

Unfortunately, garbage companies are not necessarily very good at publicity or education. (My local company's website is badly designed and it's annoyingly difficult to even find the page with the rules.)

</comment><comment><USER36> "...or burning it in huge incinerators like the one in Chester, which already torches around 3,510 tons of trash, the weight equivalent of more than 17 blue whales, every day."

I love that they compare it to the weight of a blue whale!

"There isn't much of a domestic market for US recyclables – materials such as steel or high-density plastics can be sold on but much of the rest holds little more value than rubbish"

It's clear to me from the article, does that mean paper and cardboard as well? It seems to be mentioned that China won't take it, but is that getting burned now?

<comment><USER37> IIRC it's the mix that's the problem. Pure newsprint has value, but it takes very little laminated paper or food contamination to make it cheaper to throw it all out than to sort it.

<comment><USER19> Another issue is that optical scanners read the code on plastics, but the black plastic on things like to-go coffee can't be read (they absorb the light).

Small changes like "Number 5 plastics cannot be black in colour" would help without any consumer impact.

</comment></comment></comment><comment><USER38> Isn't there a way to incinerate such rubbish such that it outputs energy (electricity) and any heavy or toxic materials are scrubbed? May be a bit more expensive but the tech exists.

<comment><USER39> There are. Someone I used to know in the waste industry referred to it as "recycling by thermal decomposition". Norway has deployed this pretty liberally, to the point that they actively import waste to fuel their plants.

<comment><USER40> I believe that Germany does this as well, I recall an article from a few years ago about Germany being a destination for a lot of waste in Europe because of their technology around that.

</comment></comment></comment><comment><USER41> I've been watching a few companies that convert plastic back into oil. it sounds great, but I have no idea yet if it actually works, or is just all glossy brochure.

[http://renewlogy.com/renew-energy/](http://renewlogy.com/renew-energy/)

<comment><USER13> It is either energetically expensive or dirty. Reforming carelessly is what Germany did during WW2 to make synthetic rubber and oil from brown coal. The result is the Black Triangle due to sulphite pollution.

[https://en.m.wikipedia.org/wiki/Black_Triangle_(region)](https://en.m.wikipedia.org/wiki/Black_Triangle_\(region\))

</comment></comment><comment><USER42> Funny fact, garbage was _literally the biggest_ US export to China until the ban.

<comment><USER43> That's interesting, do you have a source for that? A quick Google search turns up aircraft, machinery, and agricultural products (and doesn't mention garbage), but I'd be curious to learn more.

<comment><USER42> > For more than five years, scrap and trash has consistently been the US's > biggest export

[https://www.washingtonpost.com/news/wonk/wp/2013/05/09/china...](https://www.washingtonpost.com/news/wonk/wp/2013/05/09/chinas- crackdown-on-trash-could-make-it-harder-for-u-s-cities-to-recycle/)

And it is likely to be more as trash is often declared as raw plastic, cellulose, aluminium billets, or "electronic components" to evade numerous bans that China been enacting over the last decade.

This is also why American own _material statistics_ by US ITC is likely a better measure (access to ITC data is paid)

<comment><USER44> That article doesn't contain the quoted line. However, it does contain the following line:

>Since 2007, one of America's top exports to China has been... trash

Assuming positive intent, it is possible that the article was edited in the five hours since you linked it. However, it was written in 2013 so that seems unlikely.

<comment><USER42> I was homed onto the link by [https://qz.com/82640/china-doesnt-want-your- trash-anymore-an...](https://qz.com/82640/china-doesnt-want-your-trash- anymore-and-that-could-spell-big-trouble-for-american-cities/) the quote is from there. Did not notice that it wasn't from the original article.

</comment></comment></comment></comment></comment><comment><USER45> Imagine sorting waste is some amount of effort per item.

You could get the homeowner to do it, or you could pay people in a factory to do it.

Just like the poor economics of making your own paper, it turns out centralising all the effort works out to less effort expended overall.

I therefore don't really see the appeal of the European model of having homeowners separate glass, plastic etc. It seems to simply be a way to make hundreds of mllions of people waste a few minutes each, rather than employ a few thousand full time at a lower total economic cost.

</comment><comment><USER46> Not even getting power out of burning the stuff.

This from the place that once had a power plant with a huge illuminated sign "Electricity is Cheap in Chester".[1]

[1] [https://ruins.wordpress.com/2006/11/10/electrical-power- and-...](https://ruins.wordpress.com/2006/11/10/electrical-power-and- corporate-identity-pecos-delaware-generating-station/)

</comment><comment><USER47> I find it difficult to imagine the USA giving up its plastic addiction, given the high levels of consumption and the convenience plastic provides.

I think a reasonable approach for regulators might be to require all single- use plastic packaging to be industrially compostable (corn-derived etc). This way you still get the convenience of the packaging, no need to change habits, but the waste can all be turned back into soil without pollution.

<comment><USER48> I get compostable cups... The liquid will only be in them for a short time.

But can a compostable bottle last the months needed to hold a beverage on the shelf?

</comment></comment><comment><USER49> I'm convinced that a tax on all plastic containers is nessecary to avoid the negative externalities of manufacturing them.

</comment><comment><USER50> I am surprised we are not building more Plasma Arc systems to process the waste. Surely this would be better than creating all this dioxin in the air.

[https://en.wikipedia.org/wiki/Plasma_gasification_commercial...](https://en.wikipedia.org/wiki/Plasma_gasification_commercialization)

</comment><comment><USER51> >The conscientious citizens of Philadelphia continue to put their pizza boxes, plastic bottles, yoghurt containers and other items into recycling bins.

Pizza boxes are not actually recyclable due to the amount of grease they absorb which is unable to be separated.

</comment><comment><USER52> what about like a really really really deep hole

<comment><USER53> This is already done. Some of California's "recyclables" are transported by rail to large desert canyons in Nevada that are literally filled to the top with garbage. The scale of these landfills are impressive. Nevada is a popular large-scale waste terminus precisely because deep desert canyons are plentiful and cheap.

<comment><USER54> I guess I'm supposed to have faith that whoever came up with this thought it through.

It probably depends on which recyclables are going, but this seems a lot like the geologic analogue to "let's just throw all this crap in the storm drain"...

</comment></comment></comment><comment><USER55> Something is wrong with the design here. Dioxins aren't a problem if covanta incinerates at a high temperature. Safe incineration to burn trash and generate power is doable. The standard is too low here, it seems.

</comment><comment><USER56> Can we just gather all the trash into one giant ball and launch it into space?

If Dyson sphere has it's place in global solutions space then giant trash ball should too.

<comment><USER57> Sure. You'll just have to pay $2,500/kg for your trash pickup. (Probably more for escape velocity...)

<comment><USER56> true, but just to clarify (seems like everyone is missing it), I was referencing Futurama.</comment></comment></comment>


Unexpected, star-spangled find may lead to advanced electronics - <AUTHOR> http://exactlyscience.com/archives/11474.html <comment><USER2> Blogspam of

[http://www.utdallas.edu/news/2017/3/20-32477_Unexpected- Star...](http://www.utdallas.edu/news/2017/3/20-32477_Unexpected-Star- Spangled-Find-May-Lead-to-Advanced_story-wide.html)

Paper full text:

[http://onlinelibrary.wiley.com/doi/10.1002/adma.201606264/fu...](http://onlinelibrary.wiley.com/doi/10.1002/adma.201606264/full)</comment>


Michelin reinvents the wheel, electric motors help to retire the combustion engine - <AUTHOR> http://www.theenergyroadmap.com/futureblogger/show/1365-michelin-reinvents-the-wheel-electric-motors-help-to-retire-the-combustion-engine

<comment><USER3> A better write up without the hype

[http://www.motorauthority.com/michelins-active-wheel- technol...](http://www.motorauthority.com/michelins-active-wheel-technology- in-detail.html)

</comment><comment><USER4> Look at heavy equipment LeTourneau loved electric wheel motors. He built huge scrapers, tractors, and offroad trucks with them. <http://en.wikipedia.org/wiki/R.G._LeTourneau>

One big disadvantage of wheel motors is greater unsprung weight. This will make for poorer ride quality, or more expensive/complicated suspension systems. Because the wheel needs to move over bumps, if it has less mass, it can accelerate with less energy input.

<comment><USER5> LeTourneau (a personal hero of mine) powered his giant square-wire-wound electric motors with even more powerful diesel engine/generator sets. His machines were diesel powered with electric transmissions.

The article misses the "elephant in the room" point that _the electric motors are the easy part_. They always have been. It doesn't much matter if you cram the electric motor into the wheel or under the hood. Getting a power supply with enough power density and a short enough charge cycle that its actually feasible for daily use is the silver pearl.

<comment><USER6> > _His machines were diesel powered with electric transmissions._

Large mining machinery (Haulpaks) are the same - electric with a diesel power plant.

I don't believe the wheel weight is a big issue in these cases - <USER2> for the AC systems, which are somewhat simpler and more robust (in terms of the wheel motor, the actual control system is much more complex).

The reason they use an electric system for Haulpaks is varied - but basically it's due to the fact that a mechanical drive system is almost infeasible at that size/load/torque. An electric transmission system is easier to control and more robust.

Also, electric lets you control the torque much better, particularly in the AC case where they can adjust phase/freq/etc to keep it controlled.

<comment><USER7> This technology is also common in cruiseships.

<comment><USER8> Diesel-electric locomotives work like this too. You can run your diesel engine at its most optimal rpm which makes it more efficient.

This is how I hope they'll build gas-electric or diesel-electric hybrids in the future.

</comment></comment></comment></comment></comment><comment><USER9> The problem with wheel motors has historically been unsprung mass (the mass of the portion of the car that moves with the wheel, rather than with the chassis -- typically the tire, wheel, brakes, suspension upright, and half of the driveshafts, springs, dampers and suspension arms).

The problem with unsprung mass is that it lowers the amount of available friction (for cornering, acceleration or braking) on bumpy roads. What happens is that the inertia of the unsprung mass as it's cresting a bump partially or completely offsets the downward force of the weight of the car, and the tire no longer has any normal force with which to create friction.

A good active suspension can help by measuring the force of the tire on the road and attempting to keep it roughly constant (by actively shoving around the suspension). But historically active suspensions have been energy hogs, soaking up something like a liter of fuel per hundred kilometers. It's possible that newer power electronics and an attempt to actually focus on energy efficiency could reduce that, but it's likely to be expensive and complicated in any case.

</comment><comment><USER8> Two concept cars with this technology:

Eco-commuter Heuliez Will [http://www.treehugger.com/files/2008/11/active- wheel-afforda...](http://www.treehugger.com/files/2008/11/active-wheel- affordable-electric-car.php)

Performance roadster Venturi Volage [http://www.autobloggreen.com/2008/10/02/paris-2008-venturi-v...](http://www.autobloggreen.com/2008/10/02/paris-2008-venturi- volage-revealed/)

</comment><comment><USER10> I've been excited by the possibility of in wheel motors ever since I first heard of them because of the combination of simplicity of the motor, and the massive simplification of mechanical systems of a car. You no longer need all the bits which connect your inefficient internal combustion engine to the wheels, and those bits lose a lot of energy, somewhere around 50% according to what I've read. There is one company that makes buses with wheel motors which quadruple the fuel efficiency of the current best diesel bus, and of course there is the electric mini prototype which got a lot of hype a few years ago.

My biggest problem assessing the technology is my complete ignorance of the mechanical/electrical engineering issues involved. One engineering grad student argued that wheel motors were no good because they destroyed the control of the car by putting all the weight at the very bottom, and that the motors were going to be subject to a lot of shocks in real world use. I don't know enough to evaluate if that is true or not, but I'm hopeful. Anyone here know more?

<comment><USER11> "There is one company that makes buses with wheel motors which quadruple the fuel efficiency of the current best diesel bus"

Given that buses are surpassed only by garbage trucks in the number of stop and starts they make in a given distance I suspect this has much more to do with scavenging energy during braking than it does with the fact the motors are in the wheels.

</comment></comment><comment><USER12> If wheels contain the motors and th motors can operate independently, it makes some really interesting things possible like rotating the car in the position (wheels on other side of the car roll to different directions).

</comment><comment><USER13> Great concept, but the article lacks any teeth. And the links don't work. Anyone have better links -- is Michelin really developing this seriously?

<comment><USER14> Here is the Michelin page for the Active Wheel: [http://www.michelin.co.uk/michelinuk/AfficheServlet?Rubrique...](http://www.michelin.co.uk/michelinuk/AfficheServlet?Rubrique=20061224112323&Langue=EN&news_Id=23759)

But for much more detail check out the press release (pdf): [http://servicesv2.webmichelin.com/frontnews/servlet/GetEleme...](http://servicesv2.webmichelin.com/frontnews/servlet/GetElement?elementCode=54609)

</comment></comment><comment><USER15> So what happens when you have a flat tire? You're extremely screwed?

</comment><comment><USER16> As long as the lithium ion battery is the best we got, there will be no mass replacement of combustion engines with electric. There simply isn't the energy density. Also, lithium supplies aren't sufficient.

<comment><USER17> Energy density isn't nearly the as big a problem as lifespan and cost. You have to move some things around, but if you stick the suspension and the engines in the wheels, there's room for > 500 liters of battery in most cars. Th!nk gets about 150 L in a _microcar._</comment></comment>


YouEye.com: User Testing with Webcam Eye Tracking - <AUTHOR> http://www.youeye.com

<comment><USER2> Does anyone have any idea about how this compares to Gaze Hawk (<http://www.gazehawk.com/>)?

<comment><USER3> YouEye offers gaze tracks over videos of individual user tests as well as aggregated heatmaps on each page visited by a group of testers with the same task. Gazehawk offers a single heatmap of one static image. There is no user testing with Gazehawk.

<comment><USER4> I'm afraid you're mistaken on a number of fronts:

\- GazeHawk has the features you mentioned: video gaze tracks and aggregate heatmaps. Your claim of us offering "a single heatmap of one static image" has never been true: we launched with more than that.

\- GazeHawk has user testing: that was also a launch feature.

</comment></comment></comment><comment><USER5> Having worked with webcams in the browser I find it hard to understand how you can get the resolution / accuracy needed to do eye tracking. Is there a demo anywhere? Just seeing the dot move around the screen to where you are looking would be enough to see the technology works. I guess it could also be used to control games too.

</comment><comment><USER6> Wonder if the old NN/g results for eye tracking still hold up: <http://www.useit.com/eyetracking/>.

<comment><USER3> It is a good question. One, the book was published relatively recently, but, two, the research and and testing took an inordinately long time to collect. Seems like nielsen could have benefited from SaaS based gaze tracking.</comment></comment>


Open-Source Machine Learning Repos to Inspire Your Next Project - <AUTHOR> https://heartbeat.fritz.ai/25-open-source-machine-learning-repos-to-inspire-your-next-project-3b027a90155 <comment><USER2> I'm curious why I don't see any projects applying new ML techniques to text recognition (OCR) in those "advertisements" popping up recently; is this because:

\- too boring/mundane?

\- "solved problem"/too easy? (then where are the [open source] solutions? is Tesseract-ocr advanced enough already? what's its status?)

\- too hard? (is Tesseract-ocr using the state-of-the-art techniques?)

</comment><comment><USER3> Nice wrap up of ideas, but I wonder why people don't get attention on ML project with structured data, which is the most common btw.

I know that predicting sales is not as fun as make Horse a Zebra but I think they're underrated.

pd: If you have nice ML repos with structured data I'll appreciated :)

<comment><USER4> Great point! I haven't tried it yet, but Sales Force just opensourced Transmogrifai, a platform that does just this:

[https://engineering.salesforce.com/open-sourcing- transmogrif...](https://engineering.salesforce.com/open-sourcing- transmogrifai-4e5d0e098da2?gi=f2653bb323b3)

</comment></comment><comment><USER5> Thanks for the list, I've been thinking of contributing to an OS project recently. These all look extremely interesting, hopefully I can be helpful

</comment><comment><USER6> Any of these work completely in iOS? I'm new in the field and want to embed everything in mobile

<comment><USER4> Core ML is going to be your best bet. Most training is still done server side using frameworks like TensorFlow, Keras, and PyTorch. Once you've trained your model, you can convert it to Core ML with coremltools or export it to Core ML directly if the platform supports it.

Apple has a couple tools, Turi Create and Create ML, to train ML models specifically for mobile use, but their not nearly as fully featured or widely used.

If you're interested specifically in mobile ML, check out [https://heartbeat.fritz.ai](https://heartbeat.fritz.ai). We've got a bunch of resources for mobile machine learning. If you're looking for ready-to-use models or tools to manage them in your app, check out Fritz ([https://fritz.ai](https://fritz.ai)). Disclaimer, I'm a founder at Fritz which sponsors Heartbeat. Happy to answer any questions!

<comment><USER6> I'm not sure yet whether i want to do the training on mobile, but i want to try both before i decide so thanks for the resources i'll dig into them. One important question is, are there tools to decrease the size of a model so it'd better fit on mobile? Or is that part of the training?</comment></comment></comment>


Early stage of an inPulse smartwatch appstore? - <AUTHOR> http://inpulsewatch.com/

<comment><USER2> If you're going to give this submission that title, surely you should have linked to their actual library of apps, rather than their blog posts?

<http://inpulsewatch.com/watchapps.asp>

</comment><comment><USER3> Why do you have Google ads on your app store? it looks cheap and I dont think its worth it for you guys.

</comment><comment><AUTHOR> Awesome... this guy at Cisco wrote a watchapp which controls their sliding door [http://inpulsewatch.com/blog.asp?a=blogdetails&blogid=4](http://inpulsewatch.com/blog.asp?a=blogdetails&blogid=4)

</comment><comment><USER4> > 32kB total program space, 8kB RAM

> selling these smart watches for the sharp price of $149

Cool idea, but there seems to be a massive misstep in logic somewhere in there. If it's supposed to be a thin client to the phone, then it needs to act like one (not run apps). If it's supposed to be a somewhat thicker client, you need to travel forward in time from 1988 until now and insert more space, provide an OS (even if it's single thread) to manage said apps and possibly more then an on/off button for input.

</comment><comment><USER5> I hope they can get this to the level of the Timex Datalink; so far it's still very toy like.</comment>


Non-IP Messenger App - philipp-spiess http://www.indiegogo.com/projects/non-ip-messenger-apps <comment><AUTHOR> Serval Project ([http://servalproject.org](http://servalproject.org)) does this and much more already. It's very mature and should be supported before an upstart idea, IMO

<comment><USER2> Is that the same idea? That website is confusing.</comment></comment>


Ask YC: Your ugliest hacks. - <AUTHOR>

Can be whatever you like.
At the moment I'm working on something that parses eBay URLs and let's just say this isn't shaping up to be pretty. The following is a prototype which extracts search keywords from URLs:

    def getKW(url):
        kw = ''
        if getDomain(url) == 'motors.shop.ebay.com':
            #url = "http://motors.shop.ebay.com/Parts-Accessories_Car-Truck-Parts-Accessories__f350-wheels-20_W0QQ_fxdZ1QQ_osacatZPartsQ2dAccessoriesQQ_trksidZm270Q2el1313&caz.html"
            #f350-wheels-20
            kw = urlparse(url)[2].split('__')[1].split('_W0QQ')[0]
        if getDomain(url) == 'cgi.ebay.com':
            #'http://cgi.ebay.com/ebaymotors/FACTORY-15-Mercedes-E320-300E-OEM-Chrome-Wheels-Rims_W0QQitemZ290277158739QQihZ019QQcategoryZ43955QQssPageNameZWDVWQQrdZ1QQcmdZViewItem&caz.html'
            #FACTORY-15-Mercedes-E320-300E-OEM-Chrome-Wheels-Rims
            kw = urlparse(url)[2].split('/ebaymotors/')[1].split('_W0QQ')[0]
        if getDomain(url) == 'shop.ebay.com':
            #url = 'http://shop.ebay.com/items/__mini-cooper-rims?_trkparms=72%3A543%7C66%3A2%7C65%3A12%7C39%3A1&caz.html'
            #mini-cooper-rims
            kw = urlparse(url)[2].split('/items/__')[1]

        return kw if kw else False
 <comment><USER2> It's said I once wrote a Perl script to obtain queue times in a call center that took a screen capture via VNC, then carved up the snapshot into tiles for each queue and then OCR'd each tile to get the queue time. The time was then shoved into memcache and the process repeated. I acknowledge nothing.

</comment><comment><USER3> u may want to use regex to reduce / eliminate if checkings

i use newlisp, this is the code:

(set 'urls '(

"[http://motors.shop.ebay.com/Parts-Accessories_Car-Truck- Part...](http://motors.shop.ebay.com/Parts-Accessories_Car-Truck-Parts- Accessories__f350-wheels-20_W0QQ_fxdZ1QQ_osacatZPartsQ2dAccessoriesQQ_trksidZm270Q2el1313&caz.html)"

"[http://cgi.ebay.com/ebaymotors/FACTORY-15-Mercedes-E320-300E...](http://cgi.ebay.com/ebaymotors/FACTORY-15-Mercedes-E320-300E-OEM- Chrome-Wheels- Rims_W0QQitemZ290277158739QQihZ019QQcategoryZ43955QQssPageNameZWDVWQQrdZ1QQcmdZViewItem&caz.html)"

"[http://shop.ebay.com/items/__mini-cooper- rims?_trkparms=72%3...](http://shop.ebay.com/items/__mini-cooper- rims?_trkparms=72%3A543%7C66%3A2%7C65%3A12%7C39%3A1&caz.html)"))

(define (getKW url)

      (find {([^/|^_]*)(_W0QQ|\?)} url 1) ;find using regex

      $1) ;return the first matched string inside (bla*)

(map println (map getKW urls))

;f350-wheels-20

;FACTORY-15-Mercedes-E320-300E-OEM-Chrome-Wheels-Rims

;mini-cooper-rims

<comment><AUTHOR> The particular hangup I faced when using regex was with this URL: [http://vi.ebaydesc.com/ebaymotors/ws/eBayISAPI.dll?ViewItemD...](http://vi.ebaydesc.com/ebaymotors/ws/eBayISAPI.dll?ViewItemDesc&item=290277158797&t=1227377775000&ds=2&seller=la- wheel-and-tire&js=e583:1&hr=http://shop.ebay.com/?_from=R40&caz.html)

>>> x = re.compile('(?:(item|t|hr)=(\d+))')

>>> x.findall(url)

[('item', '290277158797'), ('t', '1227377775000')]

I can't for the life of me figure out how to get the hr value. I started messing around with regex again, but no luck so far.

I can do the same with Python's string methods:

>>> hr_start = url.find('hr=')

>>> hr_end = url.find('&',url.find('hr='),len(url))

>>> url[hr_start:hr_end]

'hr=<http://shop.ebay.com/?_from=R40'>

It's just messy as hell, it'd be nice to do everything in one swoop.

<comment><AUTHOR> Ok, mission accomplished methinks:

>>> x = re.compile("[\\\?&](seller|item|hr)=([^&#]*)")

>>> x.findall(url)

[('item', '290277158797'), ('seller', 'la-wheel-and-tire'), ('hr', '<http://shop.ebay.com/?_from=R40'>)]

</comment></comment></comment><comment><USER4> I desperately needed to find a way to change the java.library.path at runtime, which is technically forbidden.

I finally stumbled upon this beautiful ugly hack (it opens up Sun's non-public class and hacks it via reflection): <http://forum.java.sun.com/thread.jspa?threadID=707176>

It even works on Mac OS X.

</comment><comment><USER5> I came up with a quite an ugly hack in Python for the EventScripts plugin (<http://python.eventscripts.com>).

It was designed to allow you to thread a request for a web page in pure python and also timeout after a while (because threading is stupidly slow via ESP on game servers)..

Code: <http://errant.pastebin.com/f3d492f2d>

That is older code but all I can find atm. It has a tendency to crash things :P

The final code had a lot of time.sleep(0) code in it too to force the threads to try and grab the GIL. Ugh :P

(also for the record the hacked "kill" extension to threading.Thread I picked up from elsewhere :))</comment>


Show HN: CollectNode – free sysadmins and devops tool - <AUTHOR> https://collectnode.com/ <comment><AUTHOR> Focused mainly in massive commands execution at Unix/Linux/Windows, generating a report that can be filtered.

for a brief description about CollectNode, check this entry: [https://collectnode.com/what-is-collectnode/](https://collectnode.com/what- is-collectnode/)

I hope it is useful, and please don't hesitate to comment anything about the tool, good or bad is always welcome. thanks!</comment>


Can Tesla justify a $300bn valuation? - <AUTHOR> https://www.theguardian.com/technology/2020/jul/18/tesla-valuation-elon-musk-profit <comment><USER2> Sure. The bumpers don't fall off all that often: [https://insideevs.com/news/434581/model-3-rear-bumper- issue-...](https://insideevs.com/news/434581/model-3-rear-bumper-issue- affected-customers/)

And when they do it's God's fault: [https://insideevs.com/news/433643/video- tesla-model-3-rear-b...](https://insideevs.com/news/433643/video-tesla- model-3-rear-bumpers-fly-off/)</comment>


The week of Universal Robots bugs - <AUTHOR> https://news.aliasrobotics.com/week-of-universal-robots-bugs-exposing-insecurity/ <comment><AUTHOR> Back in 2019, Alias Robotics reported to Universal Robots that we had found a significant amount of vulnerabilities in their UR3, UR5 and UR10 robots, across different versions of their firmware which were of relevant severity and required immediate attention. As today, Universal Robots has not take any actions and therefore show that they do not care about security, Alias Robotics is launching an initiative to empower end-users, distributors and system integrators of Universal Robots' technology with the information they so much require to make use of this technology securely. We are announcing the week of Universal Robots bugs. Stay tuned and feel free to make contributions. [https://news.aliasrobotics.com/week-of-universal-robots- bugs...](https://news.aliasrobotics.com/week-of-universal-robots-bugs- exposing-insecurity/)</comment>


Steve Jobs testing Photo Booth in 2005 - <AUTHOR> https://www.facebook.com/media/set/?set=a.10150344003354357.371772.500729356&l=c6edf34df0&type=1

<comment><USER2> It's cool to see him acting like everyone else when they first tried it. Sticking his tongue out and making silly faces. I don't know about others but I often get caught up in Steve Jobs: The Legend rather than the man.

</comment><comment><USER3> non facebook version - <http://imgur.com/mhvFW,N1MHl,UeLZL,Zgpv9,K1JBn,ViqYm,HbQp5></comment>


Ask HN: How do you organize studying for a course? - <AUTHOR>

I need feedback on how people organize the whole process of studying for particular knowledge/skills domain, be it a university course or a new technology needed for his work/startup/etc.
More specifically, the questions without ordering:
* How do you organize the study materials and documents - textbooks/ebooks, papers, lecture notes, video lectues, assignments/exercises (+ answers) - generally the knowledge sources? The missing part for me is a way for centralized access for all these documents. The best that I've come up is a personal wiki with a page for the course and links to all the relevant documents. In theory, it should work, but it becomes a mess fairly quickly after the number of documents exceed, for instance, 10-15.
* How do you manage the tasks / "atomic" things that needs to get done next (the "Next Action" in the Getting-Things-Done lingo)? Do you use software application to handle these for you, and if you do, which one? The challenge here is mainly the multiple books/documents that need to be tracked for the reading progress, exercises done progress, etc.
The applications that I've tried using the above requirements with mixed success were: Wikidpad (personal desktop wiki), Thinking Rock (desktop GTD application), MonkeyGTD (personal browser-based wiki with GTD features), ToDoList2 (desktop todo application).
To recap, I still searching for a "solution" that allows me to follow this sort of workflow on my studies. Use case scenario:
1. On the day scheduled for study, I open the application and I see the very next concrete things that needs to get done. For instance: read Section 2.3 from Book #1; read Section 3.5 from Book #3; do exercises 1, 5, 11 from Book #4 (page 345); watch video lecture #4 and take notes....
2. As I'm crossing off the things that gets done I'm adding the next actions to be done that need to show off on the "project home page" when I return for the next study session.
3. The "tasks"/"actions" provide easy access for the study resources that are involved in completing the task - for instance, hyperlinks to the documents, files, etc.
Thanks you for your patience <comment><USER2> For centralized access to course materials, try a NoSQL document database. All you need is a printer, 3-hole punch, and a binder. In addition to providing a portable, permanent archive, this approach provides linear scaling to hundreds of items, arbitrary annotation of any document, and parallel read access.

</comment><comment><USER3> Generally, I'll make sure to map out complex tasks by breaking them into simple components/milestones, each with a clear deadline.

More specifically, I've been using Google Calendar for about a year to great effect to keep track of my freelancing, the non-profit I run, and also the side jobs I take (substitute teaching and tutoring). In addition, I use it to keep track of my personal life, including social engagements/obligations and birthdays.

The "Tasks" feature and I never really got along, so instead I created different calendars for each domain. Relevant days and times are extremely easy to keep track of (as you might expect).

I'll generally store hyperlinks in the "Description" box. I'll also sometimes mark calendar events with an asterisk if there is something in the "Description" box that I need to look at (be it a hyperlink, a "Bring _____" note, or some other actionable item). If there are relevant files, I'll either keep them out on my desktop, or I'll include a hyperlink to the file in Google Docs (under the "Share" dropdown menu).

Each morning, my calendar will e-mail me an agenda for the day. Items that I don't complete get moved ahead to the next day (or to a later time that day). If I finish things ahead of schedule, I'll move them back to when I finished them and congratulate myself with a delicious and healthy fruit smoothie.

You might find that GCal is suboptimal for your purposes (I don't know how well this meshes with the GTD system, as this has worked so well for me that I've never needed to explore alternatives), and it may be a bit less automated/centralized than what you're looking for. Or perhaps you're leery of feeding information to the Googleplex. But I've found my system to be useful and unobtrusive, so perhaps others might as well.

</comment><comment><USER4> I started using OneNote my last year of school and thought it was perfect for the task. I'm not sure it's strictly superior to a personal wiki, though it's arguably easier to set up and arguably has a better UI. If you don't have Office, the web-based OneNote at <http://office.live.com> might work for you, though I haven't used it much (and I suspect it won't support entering of equations).

</comment><comment><USER5> Hi, I think its a case of 'each to their own' in terms of what works best. I have just completed a masters over three years of part-time study.

\- A4 Pad to write to do lists and general thoughts / ideas. \- Binders to store content worth printing. \- Online Bookmarking Application to store bookmarks to online content, tagged according to the course and assignment. I found the 'view later' type functionality of some apps to be useful because I could just mark a few documents for reading later when I got home from work. \- Google Calendar for noting seminar dates, submission deadlines and for loosely planning my output deadlines. \- Google Docs for writing assignments sometimes, but mostly MSWord on my PC. \- Notepad for the occasional bit of free-writing.

I would generally print my calendar off for any given month to keep me focused or remind me when I was falling behind. That would stay with me at all times, particularly for my dissertation. I tried the level of detail you suggest in point 1. but it never worked for me; I kept my planning at a higher level.

</comment><comment><USER6> Emacs org-mode: <http://orgmode.org/>

</comment><comment><USER7> Pen and Paper</comment>


Tell HN: Chicago Indie Hackers meetup - <AUTHOR> https://www.eventbrite.com/e/indie-hackers-meetup-at-sawada-coffee-tickets-47123105477 <comment><USER2> Nice. Added it to my Chicago Tech Events calendar [http://chicagotechevents.com](http://chicagotechevents.com)

<comment><USER3> Just curious, why don't you enforce HTTPS yet?

</comment></comment><comment><USER4> Feedback:

I think you should use an event site to manage this. Eventbrite is good for one-off events that require money. If you want people to come back they have to have a way to be notified about it.

<comment><AUTHOR> Thanks for the suggestion. This is the first event I've organized so haven't thought about continuity yet.

<comment><USER4> With these kinds of things. You have to start now.

<comment><AUTHOR> I have all the attendees emails – can't I email them after the event to add/invite them to a group for this purpose?</comment></comment></comment></comment>


India's mission to probe Sun before 2020 - <AUTHOR> http://timesofindia.indiatimes.com/home/science/Isros-mission-to-probe-Sun-before-2020/articleshow/31184685.cms

<comment><USER2> Slightly offtopic: The title says "mission to probe Sun" and the article starts discussing it, but it soon changes to other projects, like a Moon rover, but the transition is not very clear. I first skimmed the text and thought it was a joke article about a rover in the Sun. This is a serious article, but it has too few details, and cover (all) the future Indian space missions. I think that a more generic title would be better.

<comment><AUTHOR> I agree. Sorry for that.

<comment><USER2> Well, it's the original title and here the original title is encouraged. (I prefer an improved version of the titles, but without editorializing.) I was complaining about the newspaper's title.

</comment></comment></comment><comment><USER3> How about building some toilets for the 750 million human beings (they happen to be Indian citizens) who don't have access to basic sanitation when they wake up each morning?

Fucking idiots... probe the sun my fat brown arse.</comment>