India: obscene pics of gods require massive human censorship of Google, Facebook - <AUTHOR> http://arstechnica.com/tech-policy/news/2012/01/india-obscene-pics-of-gods-require-massive-human-censorship-of-google-facebook.ars <comment><USER2> A little theological question...

If the beings so depicted are gods, then how can these picture be considered "obscene"? Maybe pictures of mere humans in whatever positions/alignments/configurations that the gods indulge in might constitute "obscenity", but because the pictures show gods doing something, doesn't that by necessity make such pictures non-obscene?

You know, sort of like how being a soldier in a war means you can kill people and not be guilty of murder. Being a god means that whatever you do is sanctified.

<comment><USER3> Using logic on anything related to religion is ... silly.

<comment><USER4> It's called "Theology"

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

<comment><USER3> Ha! Indeed it is :)

</comment></comment></comment></comment><comment><USER4> It's a big grey area of what's hate and what's not but let me tell you there are certain videos (content) on YouTube which is by any stretch of imagination : hate or racist. This content should definitely be taken down. How to detect such content is matter of active research in the US and at India.

<comment><USER5> I absolutely disagree for exactly the reason you mention in your first sentence. It is a big grey area. There is no clear line between what is acceptable and what is not. Rather than censor, we should act like adults and refuse to listen to racists. It is not the government's role to decide that for us. When they do, they almost always get it wrong somehow and often corrupt the process to their own benefit just like is described in this article.</comment></comment>


The Problem with Feedback - <AUTHOR> https://www.theatlantic.com/technology/archive/2018/11/why-ratings-and-feedback-forms-dont-work/575455/ <comment><USER2> One issue I have is when feedback is clearly being collected with intent to manipulate, like with a cable company. They ask you to specifically rate the individual person, and you know that the person sitting in a call center all day might lose their job because of a bad rating. You might give a good rating even if you had bad service (or at least you'll give a 5 instead of a 3). Then the company turns around and advertises that they have the best customer satisfaction ratings, etc. when in reality everyone hates them, but doesn't want to blame it on the poor person stuck in the call center.

<comment><USER3> >and you know that the person sitting in a call center all day might lose their job because of a bad rating.

It's more likely they'd lose their job if they consistently receive bad ratings, from several different customers. And they should.

Given how much it costs to bring on new employees it's more likely that one bad review results in a consultation, additional training, etc.

<comment><USER4> My girlfriend works in retail, and every month there's someone who gives her a bad survey because she was following company policy or because the customer didn't listen to her when she was advising them. For example, she worked with a couple to port their phones over from AT&T despite advising them that their phones may not work on her cell network. After all was said and done she got a bad survey because their phones ended up not working well on her network. And her manager even caught them outright lying in the survey about how the interaction went down. She was still punished for that survey.

Customer satisfaction surveys can be a useful tool, but they're often applied as a blunt instrument on employees who have no control over the situation the customer is dissatisfied with. It's basically a lazy copout as opposed to actually fixing company policy. I tend to ignore them unless it's to give good feedback.

A more humane system would take the feedback and then interview the employee in question and their management to understand what the root problem is. But the management organizations that use these surveys are almost never humane. Plainly, they don't give a shit about any of their employees.

</comment></comment></comment><comment><USER5> Whenever I ask for feedback with friends, I say "on a scale of 1-7" which has the effect of being both a tad off-putting and rather memorable.

Assuming I care how they respond, there are a few benefits: \- people are conditioned to rate at the extremities with a 10-point scale, whereas they tend to use the whole spectrum more when the scale is reduced to seven points. \- most people don't realize that "1-10" has no true middle number. On the other hand, 4/7 is perfectly "in the middle". \- if you believe psychologists, the average persons working memory is "7, +/-2" items. In my opinion, the brain seems to treat the "2" and "3" responses on a 10-point scale as roughly indistinguishable. There is similar haziness between "6" and "7". The average person seems more capable of making distinctions across seven points.

Anyway, when you're asking for feedback (and not on a first date), consider the seven-point scale!

<comment><USER6> Curious about why you ask for feedback with friends? Do you mean to get a rating of a movie or restaurant or something - or are you looking for feedback on your friendship performance! :-)

<comment><USER5> Baha good question. Movies and restaurants is it.

I don't frequently ask friends to rate their interactions with me. ;)

Perhaps I should.

</comment></comment></comment><comment><USER7> I've been working on a startup in the user feedback space [1] full-time for the past 3.5 years, and love to see the topic of user feedback on Hacker News.

Uber doesn't want your feedback because they care about your ideas/opinions. They want it because it's critical to their business.

Put yourself in their shoes. They have 75 million users and 3 million drivers. A critical part of growth is retention: not bleeding the existing user base you have, by offering a quality service.

So how do they identify undesirable drivers to maintain the safety and quality of their service? And in a scalable way...

You ask users to give drivers a review out of 5 stars. Chances are, if multiple people give a driver 1 star, others will too. It's a pretty good proxy for driver quality.

I can definitely see how this feels "dehumanizing" and like you're a "cog in the system". You are a cog in the system. You're a cog in their automated system for keeping their service safe and high quality.

There are different kinds of user feedback, for different reasons. One kind is user interviews, where you want to hear people's ideas and opinions for how you can do better. This is pretty human. Reviews are pretty automated, and just a different kind of "feedback".

If you run a consumer company (as opposed to B2B), it isn't practical to conduct user interviews on even 1% of your entire user base. So it isn't surprising that giving feedback to consumer companies tends to be a pretty negative experience.

[1] [https://canny.io](https://canny.io)

[2] [https://www.businessofapps.com/data/uber- statistics/](https://www.businessofapps.com/data/uber-statistics/)

<comment><USER8> I give Uber drivers 5 stars unless they did something egregiously horrible, because I know that if I give 4 stars, and enough people do the same, that driver will be banned from the platform, even though most people would say that 4 out of 5 ain't bad. Similarly, if I ever actually take the time to fill out a receipt survey from a retail store, I just give full marks across the board, because I know that otherwise some poor underpaid single mom is gonna have to "be accountable" for my responses to an uncaring corporate drone. On the other hand, a person giving a 1 to an Uber driver or bad marks across the board on a retail survey is probably unduly pissed off, and upon further reflection (or exposure to the consequences of their score) even they might not agree they suffered a truly 1-worthy experience. So my question to you is, how do you distinguish signal from noise?

<comment> hugh-avherald I'm surprised Uber doesn't add a remark like "Your rating for <Driver> will be compared to your ratings of other drivers." beneath the rating. This could (a) encourage people to give 1-5 star ratings more uniformly and (b) discourage constantly giving 5-star ratings.

Depending on how much they wanted to get more uniformly distributed ratings, they could (a) make the rider rating depend on the uniformity of the ratings given or (b) just use a comparison rating ("Was this better or worse than your previous trip?").

<comment><USER9> They don't want uniform ratings. They can either show "average rating 4.7" for a driver (assuming everybody is rating 4 or 5 because they don't want the driver to be fired), or "approval rating 70%". 4.7 of course sounds better.

</comment></comment></comment></comment><comment><USER10> This is a frustrating piece to read as a startup founder and product manager because I don't think the author understand how much companies already do think about the things established in the piece.

> "If thumbs-ups or ratings on a five-point scale are not automatically > useful, what kind of feedback would be? Finely tuned feedback that targets > the system it's meant to regulate will always surpass a barrage of angry or > ecstatic reviews. Rather than trumpeting the desirability of all feedback, > apps and review sites should pursue only the information that is crucial for > making the system work better."

It's hard to know what data points correlate to making the system work better until after the fact — so developers generally have to "over ask" so you can back test data to outcomes.

Probably the best criticism of the proliferation around feedback is that it doesn't always make the customer's experience better, it just creates better conditions for the company to make more money.

<comment><USER11> "back test data to outcomes" sounds scarily like p-hacking. That is, it seems highly likely you will still not find anything actually meaningful. You are just guaranteeing that you will be able to find something.

This is especially true if you have retention numbers, already. Why bother asking if I was happy with a purchase, if I never buy again anyway.

Note that I am sympathetic. There is every chance that I will buy something again simply because the exit survey reminded me of your existence. There is also the chance having an exit survey will make me not want to come back. :)

<comment><USER12> Not so - the business is looking for real ROI, and thus will not be satisfied with topics that are "in the noise". Also, you create the measurement that establishes a problem before you apply the treatment (create new feature X or fix bug Y), and then verify after treatment that the desired affect was achieved.

<comment><USER11> If you are scanning historic data looking for correlations, you will almost certainly fall for some of the same traps that are common in p hacking.

Now, can you mitigate some by carefully doing an experiment again? Certainly. But you should also not constrain experiments to only things to have been measuring already.

</comment></comment></comment></comment><comment><USER12> I think the author has it wrong, what the author sees as a "barrage of angry or ecstatic reviews" is actually a rich array of personal experiences waiting to be interpreted.

Traditionally, this interpretation has been done wholly by humans, and was a long and laborious task. However, we can now do much of the manual work with NLP [1] - discovering topics of concern and measuring the prevalence and sentiment. This lets us ask the dataset useful questions, like "What issue is angering customers most?", and "What features should we be talking more about?"

It's a move towards a much, much wider sampling of customer experiences (compared to focus groups), and I think it should be celebrated for empowering companies to make products/services that consumers really, really like.

[1] [https://taggit.io](https://taggit.io)

</comment><comment><USER13> "Think about it: The proliferation of ratings systems doesn't necessarily produce a better restaurant or hotel experience. Instead, it homogenizes the offerings, as people all go to the same top-rated establishments. Those places garner ever more reviews, bouncing them even farther up the list of results. Rather than a quality check, feedback here becomes a means to bland sameness."

The problem is, these rating lack context. Consider a pop song with a gazillion streams on YouTube. How many of those were "unemployed" 15 year olds pretending to be sick and staying home from school? Without some sense of context those gazillion likes have little meaning.

And of course, baring some drastically awful experience __, there 's confirmation bias. The truth is most people aren't objective enough to admit they might have made a bad choice. Of course it was the best ____ ever! It was my ____. I bought it.

 __Even so, there are always idiots who will order pizza at a place that specializes in curry, or curry from a place that does Mexican. Yes, it 's on the menu. But that's doesn't mean you should order it and then complain about it.

</comment><comment><USER14> Some places want you to rate the employee (e.g. 1 to 5 stars at touchpad at checkout, or at toilet exit at airport in some countries).

Just about every time I want to rate the employee as a 5, and the company (or management?) at a low rating because the business has obviously been the one to screw up, not the employee.

Asking to rate an employee is a sign to me that the company service is poor.

<comment><USER15> Also, they hired the employee and should be around enough to be able to evaluate if the employee is doing what they want.

</comment></comment><comment><USER16> One feedback loop for the customer might be insight in what type of other customers like a place.

I actually might visit a place if I know that a particular group of people strongly dislikes it. People have different tastes and a review system might account for that.

It would require people to fill in a few questions about themselves. Or it needs cross-referenced with Facebook likes or something like that.

This information can belong to the people!

<comment><USER17> Can we identify groups of people by similar interests and personality type and classify them with a label? It doesn't seem like it would promote inclusivity and diversity among people with disparate interests since we are all "equal" but it would be very helpful for this use case. We can create labels by having people self identify who they think they are.

U.S. Patent Pending

</comment></comment><comment> mark-r I have trouble completing those surveys - I want to be fair and accurate, but it's simply not possible with subjective impressions and no guidelines. Life is too short for such angst; I generally refuse surveys when they're presented without a second thought.

</comment><comment><USER18> This is why Netflix eliminated the star ratings -- it was too hard to figure out the degree of difference inherent in four vs 5 stars, plus it was a manual step.

And to the author: kybernetes (κυβερνήτης) is the steersman of a boat, not a governor.

<comment><USER19> If you want a counterexample though, Goodreads seems to work really well with a five star rating system. Goodreads reviewers in particular seem to take the precise number of stars quite seriously, and many reviews include a line like "I _really_ wish I could give this book 2.5 stars, but GoodReads won't let me, so I had to round up/down."

I've wondered before if this says something about heavy book readers as a population, since the five star rating system doesn't seem to work that well anywhere else outside of professional critical reviews.

</comment></comment><comment><USER20> Cybernetics didn't fail expectations. It works astonishingly well. But it seems people had some pretty weird and dumb expectations when lifting it from the domain of hardware and into more "fuzzy" real-world systems. Feedback loops are an incredibly powerful tool, but they get misused (often purposefully), and then the blame for that misuse somehow falls on the feedback system.

Consider:

1) As a user, won't be satisfied with a feedback system if the company on the other end is evil. Take Uber as an example. The tension between drivers and passengers isn't caused by the 5-star rating itself. It has another critical component - that Uber set the system to squeeze out as much value out of drivers as possible. Since they essentially optimize for bad driver treatment, drivers get defensive, and this screws up user experience. Hitting with 1-stars until morale improves isn't the solution; not exploiting people is. Similar thing happens in some customer service interactions, where rating is - again - not a signal on quality, but on whether or not I hate the other person enough to want them to lose their job.

2) A rating system won't work for you if you connect it to a money-printing machine. This one should have been obvious immediately, and definitely should be by now. This is why Amazon, eBay, Yelp, et al. have problems with reviews. As long as their presence or absence impacts immediate sales, they'll be gamed to the point of uselessness.

3) Some companies like to deploy ratings to skip doing the work, and then they cry foul when the results don't materialize. Again, Uber won't solve driver problems with star ratings; that would require actually meeting and evaluating people. I can hear the screams - "but that doesn't scale!". So what. I want to go to the Moon by lifting myself by my own bootstraps, but I can't, because that's not how physics works. I'm not going to cry that I can't get what I want without doing the work that's necessary to get it.

4) Feedback loops must be actually closed for them to work. I.e. not just collecting the data, but acting on it.

5) If you can't capture the entirety of your vision in directly measurable metrics (and you probably can't), then don't follow them blindly. In particular, be mindful of what you _actually_ measure, 'lest you end up pissing off a lot of users and defending yourself with "data told me so". "You make what you measure" works both ways.

\--

TL;DR: Blame the people/companies deploying feedback systems for being clueless or having malicious intent, not the feedback systems themselves for simply working the way they work.

</comment><comment><USER21> adjust loop</comment>


Password hack of vBulletin.com - <AUTHOR> http://arstechnica.com/security/2013/11/password-hack-of-vbulletin-com-fuels-fears-of-in-the-wild-0-day-attacks/ <comment><USER2> I own a license of vBulletin. After approximately a year of experience with their codebase I decided that burning off my eyeballs with a hot spoon would be more fun. I wouldn't know where to start to describe just how bad their software is.

It doesn't end there. The folks who own vBulletin run a whole series of communities themselves:

[http://www.internetbrands.com/](http://www.internetbrands.com/)

At one point into configuring vBulletin I realized they had code in there that would allow them to monitor your site's traffic and performance. Which is genius if you run hundreds of sites yourself and want "probes" out there to discover areas that you could launch sites into. And, it is even more brilliant if you can have these "probes" be people who pay you to use software you produce. Imagine thousands of business experiments actually paying you and feeding you audience data. That really didn't sit well with me and a number of people who were awake while installing and configuring their vB software. The vast majority of folks running vB communities either don't care or don't have a clue.

There are other issues. Maybe someone else has the time to chime in.

I guess my point is that password security might not be at the top of their priority list.

<comment><USER3> Some good points there. I've always kept an eye on such business practices.

I worked for a SaaS ecommerce outfit a few years ago and they sold their stuff to all the competitors in the same market space. After a bit, they yanked it with 28 days' notice and went into direct competition with them. Assholes. Strikes me as the same sort of company.

<comment><USER2> Well, just go to their website (link in prior post) and you can see they run hundreds of forums. That always rubbed me the wrong way. I didn't learn about this until much after I purchased my vB license. Had I seen this prior to making that decision I would not have used their software. I wasn't trying to build a large community. I just thought it was a huge violation of ethics to sell people software and then go off and compete with your own customers. This isn't disclosed in the vB site. You have to dig to find who owns vB and then it's kind of in the fine print. The average prospective buyer is unlikely to discover this until much later, if ever.

</comment></comment></comment><comment><USER4> It is a joke isn't it. "Security" lol

There are 2 types of websites. Those which are important enough for you to remember a password for and those which aren't. Well the 50 or so which aren't important enough have one password and this password has been compromised at least 5 times this year. As far as I know people haven't been logging into my accounts but I guess there is nothing stopping them.

I find it really difficult to understand how this happens so often. In many cases it seems like security is an after-thought and procedures are poorly implemented.

If it is true that the vulnerability exploited has been in vB since version 4.. that means it has been there for 3 years! I wonder how sophisticated it really was? I wonder when the vBulletin last got an external security audit done..

</comment><comment><USER5> When I was working with the company that produces vBulletin, I wasn't exactly dazzled by their competence.

<comment><USER3> As someone who had to look after a relatively large vBulletin install (13000 users) for a number of years, I wasn't exactly dazzled by their competence either!

I'd go as far to say that vBulletin is a pile of crap.

<comment><USER6> Sure vB is crap... and then you look at the other options out there and realize they're even worse. Especially 5-10 years ago when many of the sites using vB started using it. It's wildly successful - at least in the niche I'm familiar with - for a reason. It's reasonably cheap, reasonably easy to work with even for nontechnical people, works reasonably well, and looks decent.

<comment><USER3> Please don't make excuses for it.

I've had to deal with the multi-day aftermath of an XSS worm twice. That's when you realise that it's as bad as it is. After that it was "get fucked" and move to phpbb which while is not a stellar product it seems to be put together with a modicum of common sense and has a responsive community and support.

<comment><USER7> What were your thoughts on XenForo?

<comment><USER3> Hell no. It's based on the Zend framework which is an even greater pile of rot!

<comment><USER8> For real? Oh a spaghetti fan I see.

<comment><USER3> Nope. Just not a fan of adding piles of abstraction on top of something that just crawls already. To be honest I'd use a different language/platform if you need to use patterns like that where they perform (java/c#).

Bit of a "no true scotsman" that one as well. Just because someone doesn't use Zend doesn't mean they write spaghetti.

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER9> I wish they would refer to password hashes as password hashes and not call them 'encrypted passwords'. Encrypted passwords screams that you don't understand security and were storing real passwords instead of hashes. (Or, more properly, salted hashes.)

<comment><USER10> Maybe we should just give up and tolerate the non-technical usage of those terms. The situation with "hash" vs. "encrypt" seems just as hopeless as with "hacker" vs. "cracker".

<comment><USER11> I realize "hash" is too technical, but "encrypt" is a technical term with a different meaning.

If they'd just used a vague handwavy word like "encoded" we'd be left wondering what they did to the passwords and it would still be just as legible to the laymen, instead of being given an actually _incorrect_ piece of information.

And a "cracker" is a subset of hackers. So as much as it makes self-identified hackers cringe, it is correct to say that a hacker broke into a system.

"encoded passwords".

<comment><USER10> In ordinary usage, "encrypt" means "to change information from one form to another, especially to hide its meaning" (Merriam-Webster). It doesn't necessarily mean _reversible_ , although in programmer jargon it does.

So hashing is a subset of encrypting, just like crackers are a subset of hackers.

<comment><USER12> I'd think "ordinary usage" would be by cryptographers and other cryptography- related personnel, not laypeople. Most of the people around where I live don't even know what cryptography is, and it's hit-and-miss whether or not they've heard of encryption.

From a theoretical point of view, hash functions are not _only_ a subset of block ciphers: hash functions and block ciphers are equivalent. You can take a hash function and build a block cipher from it (use a Feistel network). You can also take a block cipher and build a hash function from it (use the Merkle–Damgård construction).

But even if you can build one from the other, saying something is 'encrypted' implies, in even the meanest definition, that it can be decrypted. If the layperson definition does not include this aspect, then it is, well, wrong. Even if you disagree on this point, I would expect a tech journalist to endeavor to use the correct, field-standard terminology, regardless, because as Pxtl says, anyone who is familiar with even the basics of cryptography will interpret "encrypted password" in an incorrect way (i.e., they'll see it as what Adobe did).

</comment></comment></comment></comment></comment><comment><USER13> This explains the email received a few days ago:

> We take your security and privacy very seriously. Very recently, our > security team discovered sophisticated attacks on our network, involving the > illegal access of forum user information, possibly including your password. > Our investigation currently indicates that the attackers accessed customer > IDs and encrypted passwords on our systems. We have taken the precaution of > resetting your account password. We apologize for any inconvenience this has > caused but felt that it was necessary to help protect you and your account.

> To regain access to your account:

> Visit the vBulletin forums at > [http://www.vbulletin.com/settings/account](http://www.vbulletin.com/settings/account)

> Enter in your existing password followed by your new password, twice for > confirmation.

> Save this page at the bottom.

> Please choose a new password and do not use the same password you used with > us previously. We also highly recommend that you chose a password that you > are not using on any other sites.

> If you have any additional questions or concerns, please feel free to > contact our support team at > [http://www.vbulletin.com/go/techsupport](http://www.vbulletin.com/go/techsupport) > or firstname.lastname@example.com.

> Sincerely,

Of course I reset the password to another generated LastPass one, but I did wonder what the scope of the attack was.

<comment><USER14> Are you sure that email was from vbulletin?

I received the same one and it didn't come from vbulletin's domain name. If you go to the root of the domain name it says "Test page."

When you click the "read in browser" option you are taken to a page where all the links to access the forums do not work.

I thought it was a phishing attempt.

<comment><USER13> Ah, you are right:

> [http://](http://) click.shopping.ibemail. com/

Not that it matters, I never follow links in emails and went direct to vbulletin.com

I bet they emailed everyone on their stolen email list though.

</comment></comment></comment><comment><USER15> This is getting ridiculous now. I've had my password stolen probably at least four times this year.

I think that the browser developers should push for a keychain of random, generated passwords and use as many UI pointers as possible to push people to use these. Apple's implementation in Safari is what we should be aiming for, but pretty useless to me as I have Linux/Windows/Android devices that don't support Safari.

<comment><USER16> Have you tried KeePass or LastPass? They work pretty well on just about every platform.

<comment><USER10> The problem with KeePass, LastPass, etc. is that you need to hear about them, look them up, and install them. Things would be much simpler if the browser included a similar functionality by default.

Unfortunately, all three major browser vendors seem too busy pushing their own single sign-on schemes (Chrome: Google account, IE: Microsoft account, Mozilla: Persona). So they're unlikely to pay any attention to plain old password generation and storage for the foreseeable future. Which is a real pity because passwords aren't going to disappear overnight.

<comment><USER16> Instead of using a cross-browser solution that works today, you're complaining that the browser makers haven't created their own schemes.

<comment><USER10> I use LastPass, thank you very much. My only complaint is that most other people don't, and I think browser vendors are partly to blame for not doing what they can to bring about a large-scale adoption of password generation & storage best practices.

</comment></comment></comment></comment></comment><comment><USER17> Slightly off-topic, but is it common for an hacking team nowadays to have a facebook page? I could understand twitter for announcements, but the facebook interaction feels out of place, or is it just me?

Also, "We wanted to prove that nothing in this world is not safe" has a double negation, so they wanted to prove that there is something out there that could be safe?

</comment><comment><USER5> Some interesting background reading: [http://www.theregister.co.uk/2011/05/22/vbulletin_abandons_m...](http://www.theregister.co.uk/2011/05/22/vbulletin_abandons_motion_for_injuction_against_former_devs/)

</comment><comment><USER18> Helped perform hack [http://facebook.com/HolidayPalaceService](http://facebook.com/HolidayPalaceService) And then send it to. firstname.lastname@example.com</comment>


DocPad: static website generator in CoffeeScript and Node.js - <AUTHOR> https://github.com/balupton/docpad

<comment><USER2> I'm really surprised why this approach isn't used more often.

I've built several PHP and .net things like this over the years for clients, so they can author on there PC (or my console) and push static files to my hosting as static files, and still have roll back.

Seems like common sense to me, lower risk, lower server over heads, lower user error problems. Whack together a bespoke CMS/web form in a few a hours and you're done.

<comment><USER3> Yeah, I use it for prototyping EVERYTHING now. We just used it to prototype the new <http://99dresses.com/> website - in about 5 hours we had 90% of it done. I really want to get enough spare time, or get someone to sponsor it so I can set it up as a SaaS as well as develop a plugin infrastructure for it. I've got some time this week, we'll have to see how I go - bit busy with other stuff to.

</comment></comment><comment><USER4> I tried setting up ruby/octopress on my mac last night and it was a pain in the ass. Great to see a node.js alternative. With a plugin infrastructure it'll be a serious contender to Jekyll.

</comment><comment><USER5> Good stuff dude! I'm going to use this for my app's documentation.

</comment><comment><USER6> What makes it different from Jekyll?

<comment><USER3> It's written in coffeescript and node.js instead of ruby. Jekyll is also made for blogging, for instance you have a _posts directory in Jekyll, in DocPad you have a src/documents page - this allows you to create urls like src/documents/about.html -> /about, and src/documents/projects/docpad.md -> /projects/docpad, and src/documents/posts/life.md -> /posts/life. Another great thing is that you can access the query engine inside the views, and the data associated to documents can be filled with whatever key values you want - so you can do advanced filtering/queries. The benefit is that you can extend the docpad server to do whatever you want (as it is just a node.js package) even add redirects and dynamic pages to the mix. Feel free to join me on #docpad on freenode.

<comment><USER7> Isn't this how Jekyll works as well? It's just that the _posts directory is special. But the base entity is a "Page" which exactly functions as you mention unless I'm mistaken.

Also the YML frontmatter is fully accessible in the template engine (is that similar to the "data associated to documents" you mention?).</comment></comment></comment>


I have no idea what I am doing - <AUTHOR> http://joel.is/post/7192531110/i-have-no-idea-what-i-am-doing <comment><USER2> I'm surprised this hasn't received more upvotes (considering the other stuff that regularly gets upvoted here).

The message may be obvious to some, or over the heads of others, but the post is about a principle that I find worthwhile holding. It pays to always keep an open mind and always believe you can do better. It's extremely easy to fall victim to praise.

Most of us are good at what we do, but we can always improve our skills.

Maybe it's just me. I spent a lot of my school years being told how clever I was. As the young me grew confident of this fact, the less effort I would be inclined to put into learning (at school). I pursued my own interests out of school, and taught myself the stuff I really wanted to learn (computers, programming). Still, when I was first unleashed upon the internet I had a completely inflated view of my skills. It wasn't until I got involved with an open-source project and worked with some really great people that I realised quite how far I had to go. Aptitude is not competence without effort.

This experience has given me the reflex nowadays to draw back from praise. I get it all the time and can't help but enjoy it of course, but I still remember the negative impact it can have if I listen to it too much.

Now perhaps my co-founder will read this and stop calling me awesome at last :)</comment>


Pwning banks – Miika Turkia [pdf] - <AUTHOR> http://conference.hitb.org/hitbsecconf2017ams/materials/D1T4%20-%20Miika%20Turkia%20-%20Pwning%20Banks.pdf <comment><AUTHOR> Coming from "Hack In The Box - Amsterdam", here are other slides: [http://conference.hitb.org/hitbsecconf2017ams/materials/](http://conference.hitb.org/hitbsecconf2017ams/materials/)</comment>


x264 project announces first open source Blu-ray encoder - <AUTHOR> http://x264dev.multimedia.cx/?p=328

<comment><USER2> I've been using BD Rebuilder and x264 to backup and remove the garbage (endless copyright notices, trailers, logo screens, etc.) from my purchased BluRays, and it's been doing a great job. I'm amazed by how far I can compress them down and still have an incredible picture quality, even all the way down to DVD-5. Recent builds have even been able to give me this quality with single-pass video encodes, cutting my processing time drastically. Many thanks to the x264 project (and for jdobbs's great BD Rebuilder) for all your impressive work.

<comment><USER3> One of the quiet secrets of the format war is that most people would have been perfectly content with DVD-9 in conjunction with the new codecs, even for 1080p HD.

Videophiles might have noticed a few things on long, action-packed movies, and a new format isn't all bad anyhow (I'd love a BD-burner for some backup stuff that is getting annoying on DVD-5, oh look, DVD-9 media is getting reasonably priced), but the Great and Terrible Need for a new optical format was somewhat oversold. 9GB really is a _lot_ of data.

<comment><USER2> Well, 25GB BD-R blanks are going for around $2 a pop, so the format is still more expensive per MB than DVD-R. That will hopefully change by the end of this year. If you're only interested in using it for data, and don't care about the convenience of consolidation, you might do well to wait just a bit longer until the blanks and drives come down further in price.

That said, I've been getting great use out of my BluRay burner, and it's really done a lot to convince me to switch completely from buying DVD movies to buying BluRay, as I can now make backups and keep them protected.

<comment><USER3> I am planning on waiting anyhow. (I'll get one with my "next laptop", which is at least a year away most likely, barring accident.) But what I look forward to with BD is being able to back things up in fewer chunks. At the moment, 1 25GB chunk would cover all my highest-priority "critical" data. I'm clocking in at 15GB declared "critical" right now, so, not a DVD anymore, thanks to digital cameras and a baby. I commented on the price of DVD9s because last I had looked (a while ago!) they were about $4 a piece. Now they are only 2-ish, same as your cited price for a 25GB BD, and that's getting down to where I might pay for the convenience.

</comment></comment></comment></comment><comment><USER4> This post contains two .png (lossless) screenshots from Blu-rays that look absolutely horrible. I don't have much first-hand experience with Blu-rays, but I wonder if this kind of bad compression is a common thing?

I suppose the big studios do a decent job at encoding (though I might be wrong). Is this mostly a problem with smaller companies that might not be able to hire the proper expertise?

No doubt there will be an industry learning curve like with DVDs (with time they got better).

<comment><AUTHOR> _I don't have much first-hand experience with Blu-rays, but I wonder if this kind of bad compression is a common thing?_

Fortunately it's not _too_ common, but it's more common than one would like. This isn't unique to Blu-rays either; it happened a lot with DVDs. Various problems that I've seen are:

1\. Improperly done telecine (e.g. telecining two different parts of the frame at different rates, more common in animation).

2\. Badly done framerate-changing (Robot Chicken DVDs).

3\. Completely borked interlacing (Family Guy first season DVDs).

4\. Bad encoders that can't deal with massive bitrate peaks well (Suzumiya Haruhi no Yuutsu R1 DVDs, see <http://i43.tinypic.com/105b8rk.png>).

The primary problem with Blu-rays is a lack of source quality, not these kinds of mistakes: a lot of Blu-rays simply don't have any detail beyond SD because their source material is horrible (examples: Cowboy Bebop: The Movie, Close Encounters of the Third Kind).

<comment><USER5> Bad encodes, 1/2 the reason for the "magic" script we both developed <http://forum.doom9.org/showthread.php?t=134078>

Output: <http://i43.tinypic.com/2qd4wvk.png>

</comment></comment></comment><comment><USER6> My understanding is that Blu-Ray has mandatory encryption, and that those encryption keys are quite expensive. I'm not even sure that Blu-Ray Association would allow FOSS BR authoring tools.

<comment><AUTHOR> In theory it requires encryption, but no actual Blu-ray players care, so you can pretty much ignore that requirement.

</comment></comment><comment><USER4> Somewhat off topic: Has anyone heard anything about Google and VP8? Weren't they supposed to be making an announcement about it (or was that just a rumor)?

<comment><USER7> They're supposed to be making an announcement at the I/O conference next month.</comment></comment>


How I Sync Application Preferences through Dropbox - <AUTHOR> http://logan.dk/post/536565827/how-i-sync-application-preferences-through-dropbox

<comment><USER2> Why not just move the Preferences folder to your Dropbox then make a symlink?

<comment><USER3> Is there a reason why everyone recommends moving the folder and then putting a symlink in its original location? Seems cumbersome.

I don't move the folder, I just put a symlink in the Dropbox folder. That seems to work great, am I doing it wrong?

– edit: Ah, I just had a epiphany. I only have one computer, I use Dropbox for backup and to occasionally access one file or another when I happen to have to use friend's computer, not to sync several computers. It makes total sense to put the "original" files into Dropbox and to put symlinks on the individual computers if what you want to do is syncing, not backup. Is that right?

<comment><USER4> Ya, I'm almost certain that's right.

</comment></comment></comment><comment><USER5> "The Launch Agent is installed by writing the following into this file:"

Which is then followed by a file name.

So what is the following? Are we supposed to put the file name/path inside the file itself? Does "this file" mean something other than the file that follows immediately after the paragraph? Maybe "this file" means the file that was mentioned above, and the file path (below) is "the following" which should be written into the first file? The wording could be improved.

<comment><AUTHOR> Thanks, hereby corrected.

</comment></comment><comment><USER6> You're gonna love DesktopCouch: <http://www.freedesktop.org/wiki/Specifications/desktopcouch>

AFAIK Ubuntu is looking at putting that in their Ubuntu One cloud service.

</comment><comment><USER7> I've been using dropbox + symlinks to sync dotfiles and app preferences across 3 computers for a year now. Works like a charm.</comment>


Study Sheds New Light on Antibiotics Produced by Ants - <AUTHOR> https://news.ncsu.edu/2018/02/antibiotics-ants-2018/ <comment><USER2> _> "But the fact that so many ant species appear to have little or no chemical defense against microbial pathogens is also important."_

In the study, they only test growth inhibition of S. epidermidis, which is far from proving a broad claim about "microbial pathogens." In the actual paper, they do note that they need to test on a wider variety of organisms.

</comment><comment><USER3> Oh cmon... they didn't say 'ant-y biotics'?

<comment><USER4> ant-ibiotics</comment></comment>


Will Node.js forever be the sluggish Golang? - <AUTHOR> https://medium.com/@alexhultman/will-node-js-forever-be-the-sluggish-golang-f632130e5c7a <comment><USER2> > _It is productive and elegant, sure, but lacks in performance. Emerging are > projects like Fastify, and hundreds alike. They all aim to provide what > Express does, at a lower performance penalty. But that's exactly what they > are; a penalty. Not an improvement. They're still strictly limited to what > Node.js can provide, and that's not much as compared to the competition_

The whole article is badly written.

First it assumes that the lower performance is something insufferable -- when in most cases, and for most project, it doesn't matter at all.

Then it fails to understand the important of developer pool, convenience, ecosystem, etc, as if JS and Node could be willy nilly replaced by Golang for every project.

Third, it pisses (as above) on Node web framework projects, just because Node.js has a performance top (as a single process lower than Golang.

Also the importance of the overall architecture for performance is not accounted at all -- or the fact that as long as you add some database queries the speed benefit over Node diminishes...

<comment><AUTHOR> I'm sorry the article wasn't up to your standards.

<comment><USER2> It's mostly the overall tone hammered on, e.g. starting with: "Will Node.js forever be the sluggish Golang?" which is click-baity.

In fact I gave up around the insults at various Express-successors, and missed that the main point of the article is the µWebSockets.js.

Why not go into that directly and skip the rest? That's what people would want to know, not that "Node is worse than Golang in raw performance".

<comment><AUTHOR> I thought you said you had assessed the _whole_ article as bad? You didn't read past the ingress, the motivation of the work done.

<comment><USER3> He obviously went and reviewed the rest, or how would he know about the uWebsockets portion? His point is that the article is poorly written enough that he had no desire to finish it, and I fully agree. More information and less disparaging fluff would make this piece much more attractive to the engineers of the world.

</comment></comment></comment></comment></comment><comment><USER4> For Node to be a "sluggish Golang" in the first place, it would have to be otherwise functionally equivalent to Golang, which it is not. Writing your own TCP and SSL layers is also kind of nuts if your motivation for doing so is to optimize your Node apps.

<comment><AUTHOR> Node.js is very popular and some companies with lots of I/O still prefer JavaScript, they have their business logic written in it.

<comment><USER4> If it was just, "I wrote a custom network stack to make your Node apps run faster", that would be something, but Golang is completely irrelevant to the question.

<comment><AUTHOR> That's a good title. Golang is referenced many times in the text though, it's even plotted in the two graphs.

</comment></comment></comment></comment><comment><USER5> uWebsockets is an awesome project! Been following it since the start pretty much, And I'm really glad more people out there care more about performance than throwing more servers at the problem.

Keep it up alex!

</comment><comment><USER6> Thanks to OP and contributors for this progress on performance. What are still feature gaps and what is the roadmap?</comment>


Ask YC: How do you keep track of the different things you are doing? - <AUTHOR> I often work in a depth first sort of way.  Right now, I am trying to learn Weblocks and get better at Lisp by going through the Weblocks User Manual.  But as I read that, I see that it doesn't explain something all that well so I find a separate tutorial for that.  As I am reading that, I will see some Lisp concept that I want to read more about, so I open a new tab and read what Practical Common Lisp has to say about it.  While reading this I see something else I don't understand so I Google about it, and that leads me to see a quote I like so I open up Emacs to write down some thoughts on it, which makes me realize that I really need a better way to keep track of all the things I am doing, so I write a post on Hacker News about it.  In the end, I lose track of all the other threads of thought and learning that I had started.
So my question is - does anything exist that helps with this?  Something that just keeps track of the windows and tabs I have opened in a stack-like fashion seems like it would be great - even better if it lets me write notes or keeps track of where I am in each.  I know Juice tries to do this a little bit for browsing the web in Firefox but it seems not exactly what I want.  Right now I just make notes in a text document but it is distracting to any kind of flow I have going and it seems like a better way should exist.
Thanks! <comment><USER2> I think everyone's susceptible to this sort of frenetic behavior when it comes to knowledge work. We all have our own coping mechanisms, but mine may help you:

Start each day's work the night before by considering the big-level picture of what you're working on (learning LISP, starting a new marketing campaign...). Then make a to-do list of smaller pieces that sum to that component of your overarching goal. Keep what's within reason -- stretch yourself a little -- but save the rest for another day.

Then the next day work around that list. And when you inevitably encounter interesting bits that _aren't_ among your executable (clever quotes, concepts that surprise you) put them in some storage bin. This part is tremendously important for me... the "brain dump" lets me put the distraction out of mind because I know I'll return to it.

Then rinse, repeat.

Over a few weeks you start moving closer to your goals, and you even have a record of interesting things to keep your attention on a rainy day.

I know your question was about tools specifically, but the tools question becomes less important (a spiral-bound notebook works) when you separate strategy from hour-to-hour productivity.

</comment><comment><USER3> <http://orgmode.org>

You do have a limited amount of working memory, so if you pursue ten threads at once, you'll just lose track of what you're doing. But if Thread #1 is your do-my-project thread, and Thread #2 is your save-distraction-for-later thread, you'll do fine.

<comment><USER4> Seconded. You're already in emacs, and orgmode is excellent (and it should be already there). Spend a day or two learning it, and then use it - you won't regret it.

</comment></comment><comment><USER5> Pencil and paper.

No elaborate scheme needed. Write a word or two. Arrows. This is just a temporary hand-rail for support, not a documented history. If you try to make this more elaborate / formal, you lose the flow. Have a simple system.

Use Google bookmarks from the g-toolbar to make sure you don't lose links.

</comment><comment><USER6> If you're on a Mac and you're using Safari you might like Urly (<http://www.zenonez.com/urly/news.html>). It lets you make a pretty basic stack of browser links. If you don't like that (and you're a Quicksilver user), it might be worth writing some Quicksilver triggers to push and pop urls using a text file as a stack.

<comment><USER7> That's a bit too much, but shit! I can save URLs on my Dock! That just solved my immediate problem.

</comment></comment><comment><USER8> well, one partial solution would bee tree style tabs plugin for firefox. It nests the tabs you are opening so you have an easy way to backtrack and find what other tab you got to this one from, etc.

<comment><USER9> If you're a bit more conservative with your screen real estate, I'd recommend the Tab Kit plugin instead:

<https://addons.mozilla.org/en-US/firefox/addon/5447>

It includes the vertical tree-style sorting, but I prefer the horizontal mode with several rows of tabs visible -- it lets you see more at a glance.

It also color-codes each group of tabs uniquely, and lets you collapse groups. It's a handy way to open a bunch of research on one topic, then set it aside for later.

</comment></comment><comment><USER10> This is going to sound trite - but I use a notebook.

I have the things I'm working on, and a parking lot of things I think of/see/etc along the way.

Periodically - e.g. when I'm having a coffee, I go through the parking lot and (optionally) make them into tasks in the future.

If it's a webpage, I bookmark it and don't bother exploring - otherwise it's a recipe for going on some weird tangents. My bookmarks are a mess, but it's actually pretty easy to just search than come up with a filing system.

</comment><comment><USER11> delicious links work great. I add "toread" tags and other relevant categories. Every couple days I go through the toread pile, and un-tag the page (but keep it in my bookmarks).

<comment><AUTHOR> Thanks for the suggestion. I use Evernote similarly but that mostly works for things that are okay for me to read later. I am wondering more for something to keep track of things that I need to read or do now - if I am exploring something new and want to learn as much as in necessary to get up and running. With my Weblocks example - I am just diving in and there is a lot that might be in the tutorial that I don't understand but need to understand to keep going. This is fine when the depth of the stack of things I am doing to learn is shallow (for example, the one that comes up most when doing a tutorial - reading the tutorial , opening up Emacs to code it yourself, then going back to the tutorial). But when doing something where I know very little and am trying to learn a lot, the stack gets fairly big at times and that is when a program would be useful to keep track of it.

I think of tracking this stack as my memory's RAM and I feel like I am doing a lot of disk writes (to some notebook or text document). I feel like my computer has a lot more RAM, so maybe it can help me =).

</comment></comment><comment><USER12> I wrote an essay about this problem, and offered a solution to fix it. However, I'm not going to be able to hack on it until the holidays...

[http://einfall.wordpress.com/2008/08/24/enhancing- multitaski...](http://einfall.wordpress.com/2008/08/24/enhancing-multitasking- to-enhance-our-minds/)

</comment><comment><USER13> A notepad txt on the desktop

</comment><comment><USER14> I would agree that pen and paper or a single textfile you keep open all the time is the easy way to keep external memory of what you're doing without getting bogged down in a complicated tool.

However, I'd also advocate focusing by multitasking less.

</comment><comment><USER15> "There are 22 windows open in Safari, with a total of 43 tabs. Do you want to quit Safari anyway?"

Er, no. Not just yet, thanks...

</comment><comment><USER16> Read a real world book, not something on the internet.

</comment><comment><USER17> It sounds like your internet's untied.</comment>


The SMACK Stack Is the New LAMP Stack - <AUTHOR> https://mesosphere.com/blog/2017/06/21/smack-stack-new-lamp-stack/?imm_mid=0f4065&cmp=em-prog-na-na-newsltr_20170701 <comment><USER2> Maybe.

I think the LAMP Stack might be considered more of a workhorse than a racehorse though and I'm not sure we need a successor to the LAMP Stack.

I don't have a good acronym for my new "Stack" but it's basically a web server (I still use Apache's), CouchDB/PouchDB, BootStrap, and Javascript (I still use JQuery along with other libraries as needed).

That's an easy to learn and highly productive toolset for a lot of what needs to be done building web sites and web apps but there are a ton of other good choices out there as well.

</comment><comment><USER3> Is this an ad for O'Reilly books?

This new "stack" isn't going to displace LAMP or clunky integration with legacy enterprise apps anytime soon.</comment>


The Friend of a Friend (FOAF) project - <AUTHOR> http://www.foaf-project.org/ <comment><USER2> Did FOAF ever catch on in any particular domain? I remember putting the tags into one of my blogs about 7-8 years ago but I just looked it up and it's 11 years old now. The Projects page lists a few projects that use it but it appears to be an ancillary thing people are "supporting."

</comment><comment><USER3> I think foaf is still the most widely used ontology... it's really a pretty well thought out data model.

<comment><USER4> I was trying to give a response along the lines of "that's like saying <x> is the most widely used <y>", but couldn't actually think of anything that made my point.

My point was going to be that pretty much no-one really uses ontologies.

<comment><USER5> You'd be surprised how much ontologies are catching on these days. Have a look at <http://linkeddata.org/>

Ontologies and linking different ontologies have become a key part in unlocking large data sets such as Wikipedia, from governments, et cetera.

<comment><USER3> yep it is a bit of a niche, but if you poke into an awful lot of rdf files you'll see foaf:

</comment></comment></comment></comment><comment><USER6> Great idea that simply never caught on.

Could you imagine what a blog would look like if you included every microformat/social/discovery service that has occurred over the last several years?

</comment><comment><USER7> Ah, if i could only down vote. Come on folks, you discover something which was created eons ago and think it's new.

<comment><AUTHOR> Not everyone was around eons ago.</comment></comment>


Did TrueCrypt's developers embed a hidden Latin message for us all? - <AUTHOR> http://grahamcluley.com/2014/06/truecrypt-hidden-message/

<comment><USER2> Be that as it may, the "tips" on how to migrate to the likes of BitLocker are unusable.

What good do me BitLocker encrypted files when I put them on a usb drive and stick it in a Mac or Linux machine?

TrueCrypt was multi platform. That was a major appeal. Also, seeing as Microsoft and the other big players likely have ties with the NSA as well does not make BitLocker look any better.

I just want to have a multi platform encryption software that is also capable of encrypting a boot drive.

</comment><comment><USER3> Can we have a "Betteridge headline" option next to [flag]?</comment>


Tau is easier than Pi (2014) - <AUTHOR> https://www.scientificamerican.com/article/let-s-use-tau-it-s-easier-than-pi/ <comment><USER2> I have yet to hear of a single well-known mathematician who gives a damn about this.

<comment><USER3> The largest benefit as far as I can see is to lower the barrier of entry to mathematics for young people. Well known mathematicians have already passed this barrier so perhaps it's not as relatable a problem to them. I for one would have loved to learn Tau instead of Pi, and I believe educators would love to have a more engaged classroom as well.

<comment><USER4> Does defining tau := 2 * pi make math easier at all?

<comment><USER5> Yes. In particular, teaching tau instead of pi makes many operations in trigonometry more intuitive.

It doesn't matter to mathematicians because they have spent many years learning to suppress their intuition. It does matter to engineers and technicians.

</comment></comment></comment></comment><comment><USER6> "For mathematicians, pi obscures some of the underlying symmetries of mathematics and muddies up what should be elegant with extraneous factors of two. There's an admittedly grandiose idea that mathematics is the language with which we express and see certain underpinning truths to the universe."

I don't think it's overly "grandiose"... what other language can express such fundamentals and find relationships between them?

And so mathematical understanding will always benefit from natural simplifications.

There's no "issue" if we just allow both pi and tau -- calling on each as it suits the equations at hand.

They're both symbols for irrational numbers so use whichever has the least number of terms. If you mean pi use pi and if you mean 2 * pi, as is common in Fourier transforms, just use tau. Teach both and negate the popularity contests.

Then we can celebrate March 14th and June 28th with equal fan-fare.

</comment><comment><USER7> Read the actual 'Tao Manifesto" webpage which does a much better job of describing it than this article.

[https://tauday.com/tau-manifesto](https://tauday.com/tau-manifesto)

</comment><comment><USER8> > Manifesto author Michael Hartl received his PhD in theoretical physics from > the California Institute of Technology and is only one in a string of > established players beginning to question the orthodoxy.

Oh, I get it. Hartl is the Learn Enough[1] and especially Ruby on Rails Tutorial[2] guy. This whole Tau thing is a cryptic anti-Python troll.

[1] [https://www.learnenough.com/](https://www.learnenough.com/)

[2] [https://www.learnenough.com/ruby-on-rails-6th- edition](https://www.learnenough.com/ruby-on-rails-6th-edition)

<comment><USER5> Obviously not.</comment></comment>


Ask HN: A Fault-Tolerant Internet (Or Untangling the Cybernetic Supply Chain) - <AUTHOR> In many parts of the world internet access (and indirectly computer/phone login) depends on a very long trail that might be severed by power failure or crisis in intermediate countries. Offshore hosting also obscures what files or certificates might become unreachable. What would it take for a country/state/city to set up their internet infrastructure and computer software to keep working as locally as possible? Take into account that the very process of development and deployment as we know it is reliant on the internet working as intended (for software access, programming, hardware logistics, etc).
Bootstrapping of a country's communication system sounds nightmarish enough, but it's flat out impossible if all the software and hardware has built-in assumptions about what should be able to access on the other side of the world. I reckon it's no good to spoof a remote server location without the corresponding information and credentials. What will software updated look like when security certificates are out of reach?
Even the development and deployment of such contingencies is at risk. Worldwide, software developers rely on online resources and services in their usual workflow (hosting, version control, plugins, testing, coordination efforts, documentation, good ol' copy-pasting, Stack Overflow, etc). And even taking software for granted, hardware guys would need to deploy the changes in logistical darkness if done post hoc. Implementing this could be incredibly costly and disruptive for any nation, but if it is imperative the sooner the better. IT staff would get overwhelmed one way or the other, preventing or fixing it. And all of this working against unknown deadlines, utilizing services that might go offline at any time because of obscure chains of dependencies. Y2K sounds like a walk in the park all of a sudden.
So when does push come to shove? Should any country worry about the possibility of going offline? Can anything even be done to mitigate it? <comment><AUTHOR> We've told our phones and computers to lock us out if anything feels off. In doubt, they validate logins against international servers, but in absence of this we have a validation stalemate. An authentication breakdown would be specially puzzling for non-technical people. Emergency personnel might find themselves shouting at very expensive bricks if authentication goes awry, and not even knowing why. I fear officials and first responders might lose access even to their institution's intranet resources because their browsers stored all their passwords. Most people don't remember anyone's cellphone, as they use messaging apps that leverage account contacts or the like. So even if local cellular networks still worked untroubled in an internet blackout, I don't think anyone who is busy in the front-line took the precaution of printing out their coworkers' phone numbers. Governments instruct their populace remotely, and even radio and TV broadcasting depends on the people who operate it having internet access. Big services like GitHub, Gmail, etc, have regional hubs that serve content locally, but I fear that they rely on centralized servers for login auth anyways and cannot possibly be functional in a vacuum.

Let's use WhatsApp as an example. People rely heavily on it, and let's say we try to make it keep working as smoothly as possible to avoid disruptions in response work. Firstly, it should keep working as usual, but in lack of a proper connection it should default to a local server that you somehow set up almost overnight (let's take that for granted). Your first choice could be to convince Facebook to implement the changes themselves while everything still works, and blindly trust your country to manage delicate conversations. If they don't, you need to tell thousands of non-technical people who already have enough work on their hands how to manually install non-store apps. Google, Microsoft, Apple, etc, might help preemptively rolling out updates weakening authentication and security, but that's a very dangerous thought if it's done when not absolutely necessary. Maybe simply send notifications on how to proceed. Even if a nation instructs their populace to install a preexisting p2p app, can you guarantee the country's intranet will be still standing?</comment>


A type-centric redesign of Twitter.com - <AUTHOR> http://www.vcarrer.com/2009/06/twitter-unofficial-redesign.html

<comment><USER3> The screenshot looked really good. Running live, it's _way_ too cluttered and there's not enough of a relation between relevant pieces of information. I strongly dislike the lefthand column, and the lack of contract with the righthand one. Finally, the "What are you doing?" box doesn't have nearly enough prominence.

Type-centric means using size to emphasize relevance. When everything's the exact same size your design is flawed.

<comment><USER4> Agree re: lack of contract between left/right columns. The designer seems to assume that people want to read tweets first, then--if it's interesting--see who wrote it. But this doesn't make sense to me.

I follow 100 or so people but they are not all equal, and in my mind I associate their tweets with a reputation based on my previous knowledge. Some of my follows for example only tweet banal day-to-day activities, while others are sources of interesting links and/or their interests have a greater amount of overlap with my own. Thus, I almost always scan the avatar/username first before deciding if their tweet is likely to be worth the read. Having to look in two separate places in order to carry out this process is very tiring on the eyes.

<comment><USER5> I wish I could do something with some sort of like button (or even with the addition of the omnipresent up/down arrows)

Even better, I wish there was some way to automatically separate "boring life-y bits" and "interesting hobbies" out. I care about the boring life-y bits from people I know but not from people I follow because they have done cool things professionally.

But honestly the voting burden is too high to make it work I think. Also, I really wish things were like the 2ch/4chan model, where I could evaluate the quality of content on its own merits instead of on who said it. But that might just be too much.

</comment></comment></comment><comment><USER6> This type-centric redesign fails to account for information architecture. What's the most important thing on the page? Probably the tweet and the picture.

The left column with ragged right justified time and twitter client stamp draws far too much attention and is not important enough to warrant so much emphasis.

The tweet itself seems almost accidental -- the main focus is on the photo itself.

Also, remove the twitter logo because it's not needed? Really? _wince_

</comment><comment><USER7> I like the look, but at the same time it feels a little awkward. I don't like the grey lines everywhere, and the top of the page looks, well, awful.

On the upside, I like the look of the leftmost column a lot, and the three column layout works well. I like how the vertical space is highly emphasized.

Also, I never realized how awesome italicized Georgia font looks.

EDIT: Also, I think that a better color-palette would help.

</comment><comment><USER8> I display the twitter timeline in my IRC client. In an 80x25 xterm, I can see about 15 tweets. Do you really need a picture of your friend every time he or she talks?

</comment><comment><USER9> I had a very similar reaction to the most recent facebook re-design - I felt that bottom line, I was able to view much less content/information at a given time. I never understood why facebook would want to do such a thing - <USER2> increase clicks, perhaps.

(Note, I only skimmed the article)

<comment><USER10> indeed this design makes me appreciate the current one a lot more. I'm sure there is a term for this 'not liking the new design even if its better' something to do with resistance to change.

<comment><USER11> Just a short summary:

In Marketing and Strategic Management this effect is called the 9X effect. It stipulates, that you underestimate the power/usefulness of a new product 3 times and overestimate the old product 3 times as well. This means a new product has to be ten times better to be successful.

As you mentioned, underlying to this whole thing is, that most people are change averse and therefore resisting it. Only around five percent of people truly like change (early adopters). All the others have to be forced to use something new.</comment></comment></comment>


Real time, user controlled RC car + camera - <AUTHOR> http://sfrover.com/

<comment><AUTHOR> Might not be live for long, but a user on IRC posted this link. He has setup an RC car that you can control, with a camera on it. It's pretty awesome.</comment>


Show HN: Viki, a simple Wiki page in Markdown from notebook of VNote - <AUTHOR> https://tamlok.github.io/viki <comment><AUTHOR> It is something like MDWiki but with the capability to read the index file `_vnote.json` of VNote, which enables us to share one notebook or folder of VNote.

Its look is based on Boostrap's website.

Just click on the `Documentation` tab, you could see how simple it is to share lots of articles.

VNote's website is also built with Viki. [https://tamlok.github.io/vnote](https://tamlok.github.io/vnote)

Thanks!</comment>


Facebook nearing statewise dominance of Twitter - <AUTHOR> http://jhscott.posterous.com/facebook-nearing-statewise-dominance-of-twitt

<comment><USER2> Some of use just don't want to use facebook. Personally I find it like myspace, ugly and annoying.</comment>


World's largest study group and Get real-time study help - <AUTHOR> http://openstudy.com/

<comment><USER2> I poked around for a bit and didn't find any mentally stimulating interactions going on, and it was poorly organized/moderated. Anybody else?</comment>


Dandelion Seeds Fly Using 'Impossible' Method Never Before Seen in Nature - <AUTHOR> https://www.nature.com/articles/d41586-018-07084-8 <comment><USER2>
      """   """
      "" ^v^ ""
      "" ^v^ ""
      "" ^v^ ""  ... low pressure
      """..."""      held by vortex
      #########  ### dandelion falling
      """""""""  """ rising air

I wonder about the chances of creating this kind of toroidal vortex above a duct for lift. It seems necessary for the air to pass in the same direction as the lift, yet lift is normally created by throwing air in the opposite direction.

<comment><USER3> Excuse me, I'm going to go launch SyncTerm now and browse some Mystic and SynchroNet boards.

<comment><USER4> I'm going to dig through the alt.fan.warlord archives

</comment></comment></comment><comment><USER5> If you find this interesting I highly recommend you to look at some vape-trick videos. Smoke/steam is great at visualizing vortices, and it's absolutely astonishing how much aerodynamically control some people can achieve.

Creating lots of small vortices in rapid succession, merging vortices, splitting vortices, letting vortices "suck in" other vortices.

[https://www.youtube.com/watch?v=Tmv228G8R4o&time_continue=1m](https://www.youtube.com/watch?v=Tmv228G8R4o&time_continue=1m)

</comment><comment><USER6> > Previous studies have found that dandelion seeds always have between 90 and > 110 bristles, says Nakayama

Those poor research assistants. Imagine counting hundreds of dandelion bristles every day. Probably still not possible with AI/image recognition either.

<comment><USER7> That would 100% be possible with image recognition. Segment using UNet, then measure the remaining joined pixels.

(Well thanks for the downvotes. I do this as my job, so I guess I'm doing the impossible or something)

<comment><USER8> Perhaps people are wondering how your UNet is going to see the bristles on the other side of the dandelion seed.

<comment><USER9> Take photos from multiple angles?

<comment><USER10> Now you have a pretty ugly correspondence problem to solve.

<comment><USER11> I'm glad we have experts who can count to 100 instead. /s

</comment></comment></comment></comment></comment></comment><comment><USER12> That was a lovely little diversion! There's a brief 1 minute clip in the article that's worth watching.

I do have one question though, how is the air flowing up through? It the seed not falling for that to happen?

<comment><USER13> Yes, the seed is falling, but the vortex slows the fall enough for it to be useful in distributing the seed as far as possible.

<comment><USER14> Some seeds have a small leaf attached, making them spin as they fall and slowing their descent for the same purpose. It's not about flying, just about prolonging the time spent in a moving body of air.

<comment><USER15> Sycamore and linden are the perfect example of this.

</comment></comment></comment></comment><comment><USER16> Oh look, a vortex ring. Hermann von Helmholtz, while studying fluid dynamics predicted that vortex rings had to exist.

[https://www.youtube.com/watch?v=Bcr9-93wXng](https://www.youtube.com/watch?v=Bcr9-93wXng)

</comment><comment><USER17> It's like nature's had millions of years to crunch through its own AI / machine learning of evolution and adaptation, and we're about to unleash the same thing on an impossibly faster scale. Imagine the technological breakthroughs that are going to happen.

I'm optimistic.

<comment><USER18> Genetic algorithms have been around in CS for a long time, in lots of highly effective optimization problems, particularly in structural problems. They don't seem to be as good for AI/ML problems (though the jury is still out in hyperparameter type stuff). Gradient descent via backpropagation is quite effective here, and that is very much _not_ like how the dandelion pod evolved.

<comment><USER19> Maybe that's as meta as it gets about evolution. The mechanisms of evolution itself are put under selection pressure once we put alternatives out there.

Once we truly break the barrier between metal and meat, artificial processes may create real life in completely unforeseen ways. Gives a new ring to "asexual reproduction".

</comment></comment></comment><comment><USER20> I always thought dandelion seeds were so open to reduce weight while still catching a decent amount of the wind in its cross section, approximating the flight of a dust particle.

Makes me wonder how much more of the wind a dandelion seed can catch with a vortex compared to if it didn't form one.

</comment><comment><USER21> The result of natural/evolutionary selection?

Would be interesting to know if there are different types of dandelions (I mean the part used to "fly") used by the same type of seed, each type adapted/optimized for a particular climate (e.g. humid for asian areas, dry for african areas, windy for coastal areas, ...).

<comment><USER22> The criteria for adaptive evolution, in the classical Darwinian sense, are:

1). Reproduction. 2). Variation between the products of reproduction. 3). Heritability between those variants. 4). Differential success among the variants.

Anything that has those four characteristics will experience adaptive evolution. Where it gets really fascinating is when you realize it applies to things that don't go through biological reproduction, for example the graphical user interface.

<comment><USER21> Well, about the GUI: I'm not sure that that's following the rules; most try to blindly follow trends, big companies tend to impose their GUIs, many implement anything which is low-effort (therefore already made available by 3rd parties), etc... => I don't see much selection/competitiveness here.

</comment></comment></comment><comment><USER23> Amazing that: (1) the mechanism involves a detached vortex; and (b) that it's taken millennia to understand what makes dandelion seeds fly.

<comment><USER24> Re (b) they appear to "fly" just like any other small piece of stuff, just moving with the air, so I imagine it's more "there doesn't appear to be any need to explain it".

They, dandelion seeds, appear to fly like other cotton-y plants do (eg heather [1]). I wonder if they creates these vortices too?

I'd guess not as their structures aren't regular and they don't have the weighted 'drop' to give stability?

[1] [https://oregonstate.edu/dept/nursery- weeds/email_pubs/thistl...](https://oregonstate.edu/dept/nursery- weeds/email_pubs/thistles/thistles.html)

</comment></comment><comment><USER25> This reminds me of the thing recently about spiders using electrostatic tension in the air to generate lift with a streamer of silk.

Evolution is crazy good at finding and exploiting quirks in physics.

<comment><USER26> I was going to mention this as I worked a couple of summers picking cherries and every morning you'd be plowing through spider lines about head height between the trees. There were lots of theories that got worse after a few beers at the end of the work day, but it had puzzled me for a couple of decades. Then learnt about spiders using the electromagnetic energy fields to 'fly'.

Nature is amazing.

</comment></comment><comment><USER27> I find this extremely fascinating, I've never put any efforts into thinking how this is flying - just because it felt so natural and obvious. A great example of that the obvious can hide greater details we still haven't uncovered.

</comment><comment><USER28> > Those structures act like the wings of a bird or aeroplane, generating > pressure differences above and below the wing to fly.

I thought we had settled this, airplane wings work by deflecting air downward, not by the Bernoulli effect, right?

<comment><USER29> They're different ways to describe the same phenomenon. "[B]oth 'Bernoulli' and 'Newton' are correct." [https://www.grc.nasa.gov/www/k-12/airplane/bernnew.html](https://www.grc.nasa.gov/www/k-12/airplane/bernnew.html)

<comment><USER30> > They're different ways to describe the same phenomenon.

Well ... they're actually different ways to incorrectly describe the same phenomenon.

Wind tunnels are still used for aircraft design because we can't accurately model aerodynamics.

<comment> dj-wonk Please clarify what you mean by 'accurately' ... without reducing this discussion to a coarse dichotomy between 'accurate' or 'not accurate' —- which would miss a main point of what models do and why they are useful.

My very rough understanding is that computer simulations of air flow are sufficently accurate for a high percentage of predictions for many kinds of objects. Fair? If not, under what cases does their accuracy suffer? Do we know why?

I am interested in why wind tunnels are sometimes used. Possible reasons I see are:

1\. building computer models of an object being tested is sufficently difficult that it is more efficient to test in a wind tunnel

2\. computer simulations lose significant accuracy when it comes to certain conditions ... but I don't know what these conditions are

3\. human or policy issues, e.g. some people trust a wind tunnel result more than a computer simulation.

<comment><USER31> Fluid dynamicist here.

Short version: Scale models (like wind tunnels) are useful because the most accurate simulations are extremely computationally expensive or computationally intractable, and the faster less accurate simulations are often so inaccurate that they are untrustworthy. Scale models are not 100% trustworthy themselves, and to construct and use them you need to understand similarity theory.

Long version:

The general field is called computational fluid dynamics (CFD for short). There are broadly two types of turbulent computer simulations of flows: DNS and not-DNS.

DNS stands for direct numerical simulation. These simulations are very accurate, and sometimes are regarded as more trustworthy than experiments because in a particular experiment you may not be able to set a variable precisely, but you can always set variables precisely in a simulation.

Howver, in DNS you need to resolve all scales of the flow. Often this includes the "Kolmogorov scale" where turbulent dissipation occurs. It could also include even smaller scales like those involved in multiphase flows or combustion. This is so extremely computationally expensive that it's impractical (in terms of something you could run on a daily basis and iterate on) for anything but toy problems like "homogeneous isotropic turbulence". In terms of real world problems, DNS is limited to fairly simple geometries like pipe flows. Those simulations will take weeks on the most powerful supercomputers today. It's very rare for someone to attempt a DNS of a flow with a more complex geometry, and I'd argue that such works are mostly a waste of resources. Here's an interesting perspective on that: [https://wjrider.wordpress.com/2015/12/25/the-unfortunate- myt...](https://wjrider.wordpress.com/2015/12/25/the-unfortunate-myth-of-the- hero-calculation/)

"Not-DNS" includes a variety of "turbulence modeling" approaches which basically try to reduce the computational cost to something more manageable. This can reduce the cost to hours or days on a single computer or cluster. The two most popular turbulence modeling approaches are called RANS and LES.

Instead of solving the Navier-Stokes equations as is done in DNS, modified versions of the Navier-Stokes equations are solved. If you time average the equations instead, you'll get the Reynolds averaged Navier-Stokes (RANS) equations: [https://en.wikipedia.org/wiki/Reynolds- averaged_Navier%E2%80...](https://en.wikipedia.org/wiki/Reynolds- averaged_Navier%E2%80%93Stokes_equations)

These equations are "unclosed" in the sense that they contain more unknowns than equations. In principle, you could write a new equation for the unclosed term (which is called the Reynolds stress in the RANS equations), but you'll end up with even more unclosed terms. So, the unclosed terms are instead modeled.

RANS is older, computationally cheaper, and usually computes the quantity that you want (e.g., a time averaged quantity). LES is newer, and has better justification in theory (e.g., good LES models converge to DNS if you make the grid finer, but RANS will not), but it often doesn't compute precisely what you want and the specifics of the LES models are often specified in inconsistent ways. My experience is that people tend to ignore the problems with LES or be ignorant of them. (Though I do believe LES is more trustworthy.)

The problem is that modeling turbulence has proved to be rather difficult, and none of these models work particularly well. Some are better than others, but the more accurate ones typically are more computationally expensive. Personally, I don't trust any turbulence model outside of its calibration data.

Some people lately have proposed that machine learning could construct a particularly accurate turbulence model, but that seems unlikely to me. People said that same things about chaos theory and other buzzwords in the past, but we're still waiting. Many turbulence models are fitted to a lot of data, and they're still not particularly credible. Also, machine learning doesn't take into account the governing equations. Methods which are similar to machine learning but do take into account the governing equations are typically called "model order reduction". If you want to do machine learning for turbulence, you actually should do model order reduction for turbulence. Otherwise, you're missing a big source of data: the governing equations themselves. (I could write more on this topic, in particular about constraints you'd want the model to fit which machine learning doesn't necessarily satisfy.)

Anyhow, scale models are basically treating the world as a computer. Often testing at full scale is too expensive, particularly if you want to iterate. "Similarity theory" gives a theoretical basis to scale models, so that you know how to convert between the model and reality.

One of the most important results in similarity theory is the Buckingham Pi Theorem: [https://en.wikipedia.org/wiki/Buckingham_%CF%80_theorem](https://en.wikipedia.org/wiki/Buckingham_%CF%80_theorem)

This theorem shows that two systems governed by the same physics are "similar" if they have the same dimensionless variables, even if the physical variables differ greatly.

If any of this is confusing, I'd be happy to answer further questions.

<comment> dj-wonk Wow, thanks for your well-written response. I didn't quite follow all the details; in any case, I have a slightly better idea of what is going on. Next, I look forward to learning a bit more about laminar versus turbulent flow.

I can relate to your comment: "Some people lately have proposed that machine learning could construct a particularly accurate turbulence model, but that seems unlikely to me". A healthy skepticism is important. Different inductive biases in various machine learning algorithms will have a significant effect here, I'd expect.

<comment><USER31> Glad to help.

Here's some additional comments you or some other reader might find useful:

Dimensional homogeneity is the most important constraint I think most machine learning folks would miss. It's not really an "inductive bias", rather something which everyone agrees models need to satisfy, so it should be baked in from the start. This is trivial to meet, actually; just make sure all of the variables are dimensionless and it's automatically satisfied. (Depending on the larger model, you might have to convert back to physical variables.)

[https://en.wikipedia.org/wiki/Dimensional_analysis#Dimension...](https://en.wikipedia.org/wiki/Dimensional_analysis#Dimensional_homogeneity)

In terms of "inductive biases", I'm not certain what that would entail in terms of turbulence, but I'll think about it. Might be something to figure out empirically.

Turbulence models which satisfy certain physical constraints are called "realizable". Some of these constraints are seemingly trivial, but not necessarily satisfied, like requiring that a standard deviation be greater than zero. (Yes, some turbulence models might get that wrong!) The "Lumley triangle" is a more advanced example of a physical constraint that a (RANS) model needs to satisfy that often is not satisfied.

I'd be interested in applying machine learning type methods (combined with the model order reduction approaches to include information from the Navier-Stokes equations), but I'm not knowledgeable about them. My impression is that most people applying machine learning to turbulence are novices at machine learning. And I imagine most machine learning people applying machine learning to turbulence are novices in turbulence and wouldn't know much anything about the realizability constraints I mentioned.

Another issue worth mentioning is experimental design. I think the volume of data needed to make a truly good turbulence model is probably several orders of magnitude higher than anything done today for turbulence. Experimental design could make this more efficient. I don't think most machine learning people worry much about this. They seem to focus on problems which can be run many times without much trouble. Acquiring data for turbulence is slow and hard, so it's outside their typical experience.

</comment></comment></comment></comment></comment></comment></comment><comment><USER32> Fascinating! For what it's worth, detached vortices are also critical to the takeoff and landing of airplanes with delta wings, such as the Concorde.

</comment><comment><USER33> Does anybody have a link to a video of the lasers creating small vortices just above the dandelion surface?

<comment><USER34> [https://static- content.springer.com/esm/art%3A10.1038%2Fs415...](https://static- content.springer.com/esm/art%3A10.1038%2Fs41586-018-0604-2/MediaObjects/41586_2018_604_MOESM4_ESM.mp4)

[https://static- content.springer.com/esm/art%3A10.1038%2Fs415...](https://static- content.springer.com/esm/art%3A10.1038%2Fs41586-018-0604-2/MediaObjects/41586_2018_604_MOESM5_ESM.mp4)

[https://static- content.springer.com/esm/art%3A10.1038%2Fs415...](https://static- content.springer.com/esm/art%3A10.1038%2Fs41586-018-0604-2/MediaObjects/41586_2018_604_MOESM6_ESM.mp4)

[https://static- content.springer.com/esm/art%3A10.1038%2Fs415...](https://static- content.springer.com/esm/art%3A10.1038%2Fs41586-018-0604-2/MediaObjects/41586_2018_604_MOESM7_ESM.mp4)

[https://static- content.springer.com/esm/art%3A10.1038%2Fs415...](https://static- content.springer.com/esm/art%3A10.1038%2Fs41586-018-0604-2/MediaObjects/41586_2018_604_MOESM8_ESM.mp4)

<comment><USER35> Thank you. That first video is just mesmerizing.

</comment></comment></comment><comment><USER36> Wow, new parachute designs may be possible then! They will look scary, but can be more effective.

<comment><USER32> Probably not! This phenomenon is not scale-independent. There is a parameter called the Reynolds number (Re for short) which is the ratio of intertial forces to viscous forces. For a dandelion seed Re is small which is the key to the stability of the vortex.

For a parachute, the Re number is much higher which makes the dynamics of the flow chaotic (called turbulence). There is a critical Re number beyond which There is no way keep the vortex stable, or as they call it, the vortex bursts.

<comment><USER31> You're most likely right, but there is at least one caveat which might be able to help if we're lucky. (I'm a fluid dynamicist, though not an aerodynamicist.)

The Reynolds number is only part of the picture. You also need a measure of the strength of the turbulence. A common measure is the "turbulence intensity", which you can think of as the standard deviation of the velocity divided by the mean of the velocity. (Though that's only exactly true in "isotropic turbulence".)

In certain circumstances you can compensate for a higher Reynolds number with a lower turbulence intensity. The bristles of the dandelion may have a turbulence reduction ability, so perhaps this is already being done. I'm not certain how to reduce the turbulence level further as in this case it's mostly an ambient property which is beyond the control of the dandelion. Some sort of honeycomb structure upstream of the bristles might help, or it might hurt; it depends on the details.

Here are some examples:

Pipe flow can remain laminar for higher Reynolds numbers if the turbulence intensity is low enough. Though special turbulence control approaches (e.g., eliminating vibrations which could trigger transition to turbulence) laminar pipe flows have been observed at a Reynolds numbers of about 100000, about 50 times higher than the typical Reynolds number where laminar flow ends.

Here's a quote from a review article:

[https://www.annualreviews.org/doi/abs/10.1146/annurev- fluid-...](https://www.annualreviews.org/doi/abs/10.1146/annurev- fluid-122109-160652)

> The impression gained from presenting data in this way is that there is a > transition between two definable states. One is the relatively rare but > well-defined state of motion, laminar flow, and the other is the more common > and ill-defined state of turbulence. Experimental evidence suggests that the > laminar state can be achieved in pipe flows over a wide range of Re with the > record standing at Re = 100,000 by Pfenniger (1961). Reynolds himself > managed to achieve Re = 13,000, and Ekman (1911) later improved on this to > ∼50,000 using Reynolds' original apparatus. [...] Achieving laminar flows at > high values of Re is an indication of the quality of an experimental > facility and gives some confidence that the observations will not be > contaminated by extraneous background disturbances such as entrance flow > effects, convection, and geometrical irregularities.

Matching the turbulence intensity of two wind tunnels is often necessary to make the results comparable between the two wind tunnels. In the first volume of Sidney Goldstein's "Modern Developments in Fluid Dynamics", there's a plot showing (if I recall correctly) the Reynolds number at which the "drag crisis" occurs as a function of turbulence intensity. This basically means that the drag coefficient can be very sensitive to the turbulence intensity, at least in special circumstances.

(Why I wrote this: In my dissertation, I have an entire section about how turbulence intensity is too frequently neglected in analyses, particularly for the problem I'm studying for my PhD.)

<comment><USER32> I agree with the importance of the freestream turbulence intensity, but at high Re numbers, it's extremely hard to control it.

It can be shown mathematically, using a technique called parabolized stability equations (PSE), that small disturbances amplify rapidly thorough non-linear interactions in the frequency space. Hence, although it's possible to create a laminar flow at high Re number in the lab, it's extremely hard to achieve in nature.

One interesting case of this is the Rutan's Voyager airplane in the 80s. It was designed to have a laminar flow over its wing to reduce drag. It worked quite well until it faced rain drops at some point which messed up the aerdynamics of the wing and caused the airplane to stall. At that point, they had to add vortex generators on the wing to prevent the stall.

<comment><USER31> Thanks for the interesting example. You're right that this is unlikely to redeem a scaled up dandelion, but I thought it was still worth mentioning as it's often overlooked.

I work in internal and multiphase flows, and changing the turbulence level is much easier there than in aerodynamics.

I'll also have to look at the parabolized stability equations as I am not familiar with them. If you have a preferred reference, I'd be interested.

</comment></comment></comment></comment></comment><comment><USER37> > Never Before Seen in Nature

> Many insects harbour such filter-like structures on their wings or legs, > suggesting that the use of detached vortices for flight or swimming might be > relatively common

I sense a bit of disconnect between the article and the headline.

<comment><USER25> Also:

> When some animals, aeroplanes or seeds fly, rings of circulating air called > vortices form in contact with their wings or wing-like surfaces.

> Researchers thought that an unattached vortex would be too unstable to > persist in nature.

I guess those animals and seeds aren't natural then?

<comment><USER38> Aren't those two sections contrasting "in contact" with "unattached"?

<comment><USER25> Huh, looks like I misread that bit. Good catch!

</comment></comment></comment></comment><comment><USER39> Perhaps ignorance on my part, but: why do they require highspeed cameras and laser illumination to figure this out in 2018? Shouldn't physics by able to model such a relatively simply structure and how air would move through and around it?

<comment><USER40> "Relatively simply structures" can be nigh impossible to model...

[https://en.wikipedia.org/wiki/Three- body_problem](https://en.wikipedia.org/wiki/Three-body_problem)

</comment></comment><comment><USER41> Webpage not available

The webpage at [https://www.nature.com/articles/d41586-018-07084-8](https://www.nature.com/articles/d41586-018-07084-8) could not be loaded because:

net::ERR_TOO_MANY_REDIRECTS

</comment><comment><USER42> They aren't just good at flying. They're good at traveling on shoes, and releasing on hikes, finding their way in national forests and wilderness where they'd otherwise have had zero chance ending up.

</comment><comment><USER43> Is there a link to the actual journal article?

<comment><USER44> There is, right in the article: Cummins, C. et al. Nature [https://doi.org/10.1038/s41586-018-0604-2](https://doi.org/10.1038/s41586-018-0604-2) (2018).

</comment></comment><comment><USER45> I always thought dandelion seeds are like small parachutes those are slowly falling down.

</comment><comment><USER46> Could we design better parachutes using this tech?

</comment><comment><USER47> Something something "Bumblebees shouldn't be able to fly" something something.

How is it we are shocked to find out we are sometimes wrong and not shocked that sometimes we get it right?

My critique by the way is the headline, not the actual research. The headline is clickbait IMO, and just as I suppose some don't like my comment (not well thought out, emotional, etc.), the headline is the same.

E.g., consider, "Curious unexpected aerodynamic principles of dandelion seeds lead scientists to new areas of discovery"

<comment><USER48> I agree its a bad headline. Maybe "Dandelion Seeds Fly Using Method Not Previously Described in Nature", because: 1\. Of course its been _observed_ before. As the video points out, just about every kid has observed it. The claim is really that nobody has previously understood the physics of it. 2\. There's nothing impossible about it, clearly. Moreover, the article doesn't claim that people had previously analyzed the seeds behavior and came to the conclusion that it defies physics.

<comment><USER49> The vortex may not have been observed since air is mostly transparent.

<comment><USER50> Or that no one had been able to answer, "What makes dandelion seeds fly?" because no one had asked the question before. At least not asked it in a way that prompted someone to look at a floating dandelion seed close enough to notice the vortex.

</comment></comment></comment></comment><comment><USER51> I missed where they described how this was "Impossible"

<comment><USER52> "Researchers thought that an unattached vortex would be too unstable to persist in nature."

<comment><USER51> thanks</comment></comment></comment>