Show HN: Josh.ai, an AI for the home - <AUTHOR> https://www.youtube.com/watch?v=7266YkROLYM&feature=youtu.be <comment><USER2> I'm not usually one to hop on something and criticize when it's a Show HN.

But I have literally everything that this is doing already set up in my home right now using an Amazon Echo, which is $200, instead of $10,000.

I can say "Trigger lights for projector", and lights dim how I want it. Or "Trigger lights for guests" and bing, lights. I can say "Play my Lumineers station on Pandora", and my Echo will play it. And of course I can ask Echo all kinds of things like "What is the distance to the moon?" or "What is the population of India?"

Plus a lot more.

So what is the value add here? How is this different/better than Echo + IFTT + a Wink hub? I'm really genuinely curious, because this is something I am doing right now and am totally willing to spend money on to do better, but based on this short video I have no idea how this is better...

So I guess take that as constructive feedback from (presumably?) your target audience -- show me something really cool this does to get me to consider spending $10k on it.

<comment><USER3> One thing I don't like about Echo, IFTT, and others like them is the fact that everything has to go through "the cloud." If I'm sitting at home and want to dim my lights, why do I need to send my voice to Amazon's server, have it call out to IFTT, which calls back into my home? Especially since I have a data cap. All of that can easily just go through a locally-installed system and you don't need expensive hardware to do it.

<comment><USER4> That's what's driven me to write my own home automation code. (Though my code's terrible, not HN-worthy.) Anything that insists on a cloud API is out in my book. A local server is potentially worth serious money, especially if it's easy to use.

<comment><USER3> I've been toying with something similar (mostly on paper so far) involving custom GStreamer elements for voice recognition/synthesis, a Wit.ai-like intent resolver for command & control, and ChatScript-like pattern matching for conversational dialogue. My goal is to put it all behind a WebRTC and SIP gateway and have a low-latency personal assistant that I can access from virtually any device (even an old landline telephone) and that runs on my own private server. That's the dream anyway. I'm stuck on the voice synthesizer, at the moment...

<comment><USER4> I started at device control. Once I get device control where I want it on my home server, I'll expand out to being able to reach it elsewhere, and then voice.

</comment></comment></comment></comment></comment><comment><USER5> Awesome! This is great man. How long have you been working on this for, and what are you using to processing the speech (is it internally developed or are you leveraging an API or something)? This seems like a fun hack just for home.

A couple years ago in my dorm, I set up a clapper and set up a server to play my music when I was out of my dorm, so that when I was coming home I could play the sound of the clapper to get my lights started. Or if I was in my room's WiFi network, I could ask Siri to play "Turn on the Lights", and it would play an MP3 of me clapping and turn on the lights. This is obviously way cooler, and I always thought I'd one day sit and hack out something like this with Wit.ai or something. What are your plans for this?

<comment><AUTHOR> Thanks! The NLP engine is a couple years in the making, but the app and product are just a few months in. Were initially building for large homes where voice control can be super helpful, but we're already working on developer tools to let others build Josh into their systems. Your hack sounds pretty awesome. If you don't already have one, think about getting a Sonos Play:1 and tinkering with the unofficial API. You can do some pretty fun things with it.

* just a note, we are working with an official private Sonos API, it's just hard to get access if you're starting out tinkering.

</comment></comment><comment><USER6> This isn't really AI. This is just speech recognition. I did something similar back in 2011 [http://m.smh.com.au/digital-life/mobiles/aussie-hacks- siri-t...](http://m.smh.com.au/digital-life/mobiles/aussie-hacks-siri-to- automate-home-20111201-1o9zj.html)

Props for having a go at making this a company, I tried to do this with ninjablocks.com best of luck!

Happy to share lessons learned.

<comment><AUTHOR> Thanks! Would love to chat, firstname.lastname@example.com

</comment></comment><comment><USER7> > Show HN is for something you've made that other people can play with.

AFAICT, there is nothing here that we can play with and this should not be Show HN post.

<comment><USER8> While that is in the guidelines, it doesn't seem to be very strictly applied. I think the goal of the guideline is primarily to have the opportunity to get to know the project in order to critique it thoroughly, and sometimes a presentation is the only viable option.

<comment><USER7> If that's the case then the guidelines should either be changed or actually be enforced. Although I've seen dang remove the "Show HN" from posts before. To me it's misleading given the current guidelines.

I don't buy the argument that "sometimes a presentation is the only viable option." In this case and any other, the viable option is to keep working on the product until it's ready for people to test.

</comment></comment></comment><comment><USER9> Is this "an AI", or "a voice control system preloaded with a bunch of sentence command templates"?

I mean this as a neutral question, because it's cool either way, and does seem like a bizarre little hole in the current "voice control" ecosystem, but there's a difference in what I, at least as an HN reader, expect between the two things, and I wanted to give you that feedback.

<comment><AUTHOR> We're very much an AI company, and that's the focus, but the product will roll out in stages. The foundation is built on a home-made NLP engine that's pretty flexible. That said, NNs are only used for speech recognition currently. With a relatively stable NLP engine we're focused now on device integration to control the majority of IoT products our customers might have. We're implementing some learning and pattern recognition models but it will take some time before those come close to resembling any true "intelligence".

<comment><USER9> Thank you for the detailed answer. Best of luck!

Incidentally, I just complained in another post about the way that needing to "invoke" voice mode makes it much less fluent. You may at least want to pop that one on to the mental back burner to see if there's a solution you can think of for it. I don't know what, but something that makes the friction of invoking a voice app less would help a lot. (I assume this is where Amazon Echo idea comes from.)

<comment><AUTHOR> It's a double-edged sword for privacy reasons.

1\. A number of early customers we've spoken with don't like the idea of an always listening device. The perception is an invasion of privacy.

2\. There's a fear that someone outside the home could simply yell a command like "unlock the doors" to gain access. There are a number of ways one could solve this, but it's a fear we've heard about.

So the extra friction of taking out your phone and pressing a button so far seems worth the added layer of privacy and security, but we're definitely thinking hard about this one.

</comment></comment></comment></comment><comment><USER10> From the manifesto on your site:

> One of the challenges to building a fully automated house, particularly one > that grows and evolves over time, is the ability to program with ease. In > theory it's great if your sprinklers turn off when it rains, or if the > lights go on at sunset, but these actions today take a skilled programmer > many hours to assemble. [...] Even complicated queries can be effortlessly > programmed, such as, "At sunrise if I'm home slowly fade the bedroom lights > on, open the drapes, turn on the radio, and brew a pot of coffee."

That's interesting, yeah. I mean I spent a few hours recently building a little script that makes my apartment's foyer light change based on the temperature and weather during the day, and go to a dim red at night, and I really wish it was a simpler process than "kludging together a Python script".

If you've got any of that kind of stuff up and running, you should be linking to _that_ , not to a video that is essentially nothing you can't replicate with Siri and a light system that registers with HomeKit, or Echo, Cortana, or Google Now with similar plugins.

Also is there supposed to be any actual lists of brands of connected devices in the 'works with' page? All I see is greyscale photos of various anonymous devices with a word or two and an icon superimposed on them. It works with "LIGHTING" and "OUTDOORS" and "SECURITY", great, does it work with _my_ lighting or outdoors or security?

Also: If the product is named "Josh", why is its default voice female? Has "Josh" shifted from a male-coded name to a female-coded one when I wasn't looking? Or is your product intended to present as a transman who really needs to work on his voice?

<comment><AUTHOR> Gender: we have a variety of systems set up and we try to give them each a unique personality. My home, for example, is a male named Theodore with a British accent. The LA office is Scarlett and the Denver office is Samantha.

Website: we have a new website launching soon with a lot more information. You stumbled upon a page I hope to finish building today. Sorry for the confusion.

"Voice programming": We chose to focus on getting a product to market and proving customer demand before building out the entire developer portal. It's definitely the plan and we want to do it, it's just not where we see early revenue coming from and as a small team we have to pick our battles. I can't wait to open this stuff up when ready.

</comment></comment><comment><USER4> $5,000 is a pretty hefty price tag, can I assume there's some pretty impressive stuff under the hood here?

EDIT: Actually, the reservation, which is "50%", is $5,000. Is it $10,000?

<comment><AUTHOR> Yep, price tag is $10k. There's quite a bit under the hood you're not seeing in this video, particularly considering large 10,000+ sq ft homes and managing full home automation. If you're familiar with Crestron or Control4, we're playing in that space for v1.

<comment><USER4> I have little to no experience with houses that size (I live in a condo), but I understand the concept and the market segment, yes. It mentions that this functions locally, so I take it there's a server involved, that I imagine is some decent portion of this cost?

You may wish to find some way to clarify that market segment in your marketing, I think a lot of HN visitors might assume this is going to be a $99 hub or something similar. We need to see that value represented, because we are definitely going to dig up that price tag. ;D

<comment><AUTHOR> Good points! Thanks for the feedback :)

</comment></comment></comment></comment><comment><USER11> 2 things.

\- My name is Josh, I like the name.

\- I've been looking for a nice short domain. Thanks for taking a cool one. :P

<comment><USER12> I feel exactly the opposite... Why pick a reasonably common first name? Seems like a recipe for confusion...

There is a reason names like "Siri" and "Cortana" were chosen (though I'll grant you "Alexa" is a reasonably common name as well).

<comment><USER11> Cortana is the name of an AI in Halo series. That's why Microsoft chose it.

</comment></comment></comment><comment><USER13> [https://www.youtube.com/watch?v=xL7t5rV4J8Q](https://www.youtube.com/watch?v=xL7t5rV4J8Q)

Just sayin.

<comment><USER14> Competition is generally a good thing, just saying.

</comment></comment><comment><USER15> When it said turn off all the lights, i was thinking, what a thing to say.... the whole room would go dark :D

</comment><comment><USER16> Please stop calling things AIs. It just gets my hopes up.

</comment><comment><USER17> Your Stripe account is in test mode.

<comment><AUTHOR> Thanks! I am honestly amazed so many people were able to get to that page. We plan on going live with the website next week and right now it takes a fair bit of digging around to get there. That said, it is technically "public" facing so I'm fixing it up as soon as Stripe permits. Will probably disable the button in the meantime if you go back.

<comment><USER4> The "learn more" button on the josh.ai home page has the new site's top bar. It's compelling to push that. :P</comment></comment></comment>


Notes on "Camp" (1964) - <AUTHOR> https://faculty.georgetown.edu/irvinem/theory/Sontag-NotesOnCamp-1964.html <comment><USER2> Whenever I see anything by her I can't help but remember this encounter with N.N. Taleb

"I will always remember my encounter with the writer and cultural icon Susan Sontag, largely because it was on the same day that I met the great Benoit Mandelbrot. I took place in 2001, two months after the terrorist event, in a radio station in New York. Sontag who was being interviewed, was pricked by the idea of a fellow who "studies randomness" and came to engage me. When she discovered that I was a trader, she blurted out that she was "against the market system" and turned her back to me as I was in mid-sentence, just to humiliate me (note here that courtesy is an application of the Silver rule), while her female assistant gave me the look, as if I had been convicted of child killing. I sort of justified her behavior in order to forget the incident, imagining that she lived in some rural commune, grew her own vegetables, wrote on pencil and paper, engaged in barter transactions, that type of stuff.

No, she did not grow her own vegetables, it turned out. Two years later, I accidentally found her obituary (I waited a decade and a half before writing about the incident to avoid speaking ill of the departed). People in publishing were complaining about her rapacity; she had to squeeze her publisher, Farrar Strauss and Giroud of what would be several million dollars today for a book advance. She shared, with a girlfriend, a mansion in New York City, one that was later sold for $28 million dollars. Sontag probably felt that insulting people with money inducted her into some unimpeachable sainthood, exempting her from having skin in the game."[0]

[0] [https://medium.com/incerto/the-merchandising-of- virtue-b5487...](https://medium.com/incerto/the-merchandising-of- virtue-b548762658f0)

<comment><USER3> This anecdote really changes my perception of her. It seems like one of the cases where you have to divorce the author from the author to appreciate the creation.

I was going to leave some comments about her other interesting works, but I don't this I can after reading this.

<comment><USER4> Why? She may have been like that generally. She may have been having an off day. It's just one encounter, and one side of the story.

An interesting anecdote, but not something to base an entire life assessment on.

</comment></comment></comment><comment><USER5> Sontag's journals are a fun read. They are like a twitter stream of her random thoughts, from the 60s and 70s. Weird, fevered, genius stuff.

e.g. She predicted the iPhone:

> A novel about the future. Machines. Each man has his own machine (memory > bank, codified decision maker, etc.) You "play" the machine. Instant > everything [1965]

Another:

> What if everything were the same, but no one talked.

It goes on... they're great..</comment>


No bullshit guide to linear algebra – v2 - <AUTHOR> https://minireference.com/blog/no-bullshit-linear-algebra-v2-release/ <comment><USER2> This book is neat, and I hate to sidetrack any thread on HN about linear algebra, but rules are rules, even for people I like.

You're not supposed to solicit upvotes for submissions. But that's exactly how this story on HN came to be: everyone who bought the book got an email announcement that the v2 version was finished (congrats, btw!) and it specifically asked people to upvote this particular submission.

Please don't do things like that. Just a few steps past that and you've got Product Hunt and the lesser subreddits. It's a good piece of work; people would have noticed and highlighted it on their own.

<comment><AUTHOR> Mea culpa. I won't be doing that in the future (I mean writing books and posting them to HN once every two years, yes, but soliciting upvotes, no.)

</comment></comment><comment><USER3> The phrases "no bullshit" and "linear algebra" in the same sentence immediately brought to mind the essay "Down with Determinants!" by Sheldon Axler[0]. Having skimmed through the extended preview it looks like your focus is on the bare techniques and their applications rather than a playful approach, and determinants are introduced somewhat out of the blue (just as they are in almost any degree course). I realise of course that that's just a preview and the real thing could be very different. But I wonder what you think of the idea of postponing determinants until well after eigenvalues, diagonalisation and so on, when their definition and utility might be more appreciated?

[0] [http://www.axler.net/DwD.html](http://www.axler.net/DwD.html)

<comment><USER4> Disclaimer: I am very happy that books like this are written, and look forward to never seeing another $120 doorstop being used as a text for the course anywhere. What follows is criticism and a question which, if addressed, could help those on the fence about this book.

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

Speaking of Axler, his Linear Algebra Done Right is still the best book on the subject, in my opinion.

For one, it's lean. You can fit the softcover in a purse, and read it in the bathroom. It may be scant on examples, but it's a book that can be read in its entirety.

This book, at 500+ hundred pages, simply means nobody will really read it. No student is going to be reading several dozen pages of hard math EVERY WEEK - the exceptions to that are those who will do well with any other book too.

So we have a book here that, alas, is not meant to be read - in entirety, at least.

Yes, these are two very different books. But then we also have Linear Algebra Done Wrong.

A text by Serge Treil, it was written as a counter to Axler's book (and was named in jest). It covers many of the same topics, and is available as a free (!) PDF.

So, my question is - why this book? Aside from the title, what does it really do in a new way?

There's not enough in the preview for me to conclude that this book did anything Linear Algebra Done Wrong does not, so I ask those who read it (or the author).

<comment><AUTHOR> Thanks for your question, which I will respond to in a second. First let me explain how we got to 550 pages. I wanted to include a review of prerequisites material from high school math, which burned 100pp right off the batt. Then the main material (Ch2-Ch6) is just 220pp which is not bad (especially when you take into account the book is a compact format 5.5" x 8.5"). All of this was done in 2014, when I started to think about the applications of linear algebra.

But then the feature creep starts! In the introduction of the book I make the claim about how powerful LA techniques are, and how they serve as the foundation of machine learning, and generally "scientific modelling." To substantiate this claim, I decided to make a kick-ass applications chapter that SHOWS how powerful linear algebra really is (show me, don't tell me). Two years later, the result is a 270-page survey of pretty much everything I've learned over the years from engineering, physics, and computer science that used linear algebra.

> why this book? what does it really do in a new way?

The main point of this book is to teach all the LA material in an approachable, informal narrative as opposed to formal the theorem-proof approach used in most textbooks. Can serious mathematical topics be introduced using informal language, yet without saying anything outright wrong? Can I trick the reader into learning advanced topics like Fourier transforms and quantum mechanics by making the connections to basic operations explicit? Can I sneakily introduce spaced repetition by covering core ideas several times in the book using different notation and in different contexts?

<comment><USER4> Thanks for the answer!

So, the book is really three books.

How do you get around actually proving things?

<comment><AUTHOR> The book proves _most_ things, just doesn't follow the standard math format of theorem-followed-by-proof. All the definitions are reasonably clear, and most of the proofs that are accessible and educational are given (e.g. the equivalence statements about invertible matrices). The exercises and problems also ask readers to complete several other interesting proofs (with solutions in the back).

In a future pass I plan to add more proofs, wherever adding formal structure doesn't interfere with the flow.

</comment></comment></comment></comment><comment><USER5> this might be the most amazing book ever and I might even buy it and I know I'll get down votes because so many of you love books but....

part of me feels like , especially for a topic like this, I want webpages with interactive diagrams. Not last century's info dissemination tech but this century's info dissemination tech

I feel page like this

[https://pomax.github.io/bezierinfo/](https://pomax.github.io/bezierinfo/)

is far better online than any paper book on the same topic could ever be. that feels like it's probably true for almost all math, physics, and computer topics.

if I'm reading up on game ai i'd much rather have in page interactive examples than static text on a page.

this isn't in anyway meant as a comment on the book above itself. it's more a comment on tech/math/physics books in general

anyone else agree or am I alone in this way of thinking?

<comment><USER6> There exists a book already for Linear Algebra w/interactive diagrams (that explodes my CPU) [http://immersivemath.com/ila/index.html](http://immersivemath.com/ila/index.html)

I just want accompanying lectures that build intuition like these [https://www.youtube.com/playlist?list=PLZHQObOWTQDPD3MizzM2x...](https://www.youtube.com/playlist?list=PLZHQObOWTQDPD3MizzM2xVFitgF8hE_ab) or even the author standing in front of a blackboard discussing each chapter in the book and posting the lectures on the book's page. Some author's have done this like [https://cs.wheaton.edu/~tvandrun/dmfp/](https://cs.wheaton.edu/~tvandrun/dmfp/)

If it must be 'immersive' I'd also rather have a self-contained interactive book I can keep locally with signed errata updates instead of having to rely on slow websites that may be abandoned by the author or shutdown for whatever copyright reasons or ninja edited by somebody with misinformation.

Edit: or a book with an online tutor, like the one MIT made for SICP [http://icampustutor.csail.mit.edu/6.001-public/](http://icampustutor.csail.mit.edu/6.001-public/)

<comment><USER7> 'Wikipedia with intuitions' would beat out any single book trying to record them. My hope is that they one day expand their scope to not only cover knowledge but different ways of looking at it/understanding it.

Then for any given topic a given subject's 'lesson plan' could just follow a 'sequence' (a la LW) of excerpts reviewed for accuracy (in lieu of reading such excerpts out of a book) along with mediawiki/etc animations/images/videos that go along with those subjects.

I suppose it'd be a good idea to version those 'lesson plans' so later courses/syllabuses can benefit from newly-researched knowledge _after_ it has been peer reviewed and added to a later 'version' of the curriculum (i.e. mitigating the 'quality control' issue of information shared online). And of course lecturing as it traditionally exists can still thrive albeit with a more freed focus for interactive learning (Q+A, practice problems in class, or whatever transpires to be the best tool to use in dedicated class time/lecture time)... It just seems like singleton books as knowledge containers are obsolete next to the potential of QAing existing 'open source' knowledge without the publisher/etc overhead.

<comment><USER8> > _My hope is that they one day expand their scope [...]_

The "they" who make Wikipedia are just volunteer contributors. Go make it happen!

<comment><USER7> The "they" who decide the content classes which will be handled by the project (enforced as rules of the wiki) are nonprofit organizations I'll never be on the board of, so basically what cgriswald said.

<comment><USER8> Your original comment can be summarized as "I bet it would be great if a bunch of other people did a few tens of thousands of hours of volunteer work to make new tools for teaching math to me."

Which as an idle speculative wish is fine as far as it goes, but has a vanishingly tiny chance of happening in whatever way you are envisioning. (Of course, various people around the world who are working on teaching math will continue to do their best, but without paying any attention to your specific desires.)

If instead you said "Wow, I have this great idea that would be worth a large team of people spending a few tens of thousands of hours on. Does anyone have an idea about what kind of prototyping, political organizing, or other work I can do to start on a project like that so I can make my dream a reality? Is there anyone I should talk to about this?" Etc. that would be a much more interesting basis for further discussion, and might actually lead somewhere.

The volunteers (and the tiny handful of paid staff) in charge of Wikipedia are certainly interested in new ideas for improving things. If you think it's impossible that they'll ever accept an improvement, and you aren't interested in discussion, what's the point in speculating about it?

</comment></comment></comment></comment></comment></comment><comment><USER9> I've been trying to develop my maths skills beyond the high school level I was last formally educated at. My problem is, that was 20 years ago, and I've forgotten a lot of the fundamentals, but every time I try to slog through Khan Academy I get bogged down in what would be many, many months of review to get to the undergraduate level. Can anyone recommend materials that contain a high level overview of those rules and concepts that are taught at the pre-calculus level, so I can jog my memory without endless manual calculation? Linear algebra and statistics are mainly what I'm interested in learning.

Edit: This book looks like a good candidate. :)

<comment><USER10> Lang's _basic mathematics_

<comment><USER4> Anyone who recommends Lang as a learning resource should burn in their version of hell.

<comment><USER10> Really? I've used it before for others who found it useful. That's the thing about math, lots of options/styles. Just look at Spivak vs Apostol for Calc. Do you have a suggestion for him?

<comment><USER6> Lang's Algebra book before revisions contained famously difficult exercises [https://mathoverflow.net/a/10899](https://mathoverflow.net/a/10899) but I liked Basic Mathematics even if it's out of print (expensive) and full of errata issues.

</comment></comment></comment></comment></comment><comment><USER11> This is the exact sort of book I've been looking for for a long time. I work with quite a few physicists and engineers who make extensive use of linear algebra I don't fully understand (my university courses only went up to chapter 6.1's content), so I've been looking for some way to get up to speed.

</comment><comment><USER12> This is exactly like every other linear algebra book I've ever seen, other than the title. I was hoping this had been improved over v1 but it seems to be unchanged in any significant way. What exactly does the author think the bullshit is that they're leaving out?

</comment><comment><USER13> I bought the first edition of this book and I enjoyed a lot.

Ivan, can you give those of us with the first edition a summary of the changes?

<comment><AUTHOR> The "core material" is pretty much the same. It covers all the computational, geometric, and theoretical aspects of linear algebra as required for a first- year course.

The main difference is the applications. Instead of one chapter, I expanded this part to three chapters that cover applications to chemistry, electronics, economics, optimization, probability theory, and even quantum mechanics. All of these sounds like fancy stuff, right? Actually they're simple applications of basic ideas of vectors and matrix operations, so it's quite easy to pick up once you learn LA.

BTW, if you bought the book the pre-release version through gumroad, you have access to v2 as well. Check your email—I just sent out an update.

<comment><USER14> Do you plan to add one on graphics?

<comment><AUTHOR> There is already a section on computer graphics[1] that covers basic homogenous coordinates (instead of representing points as 3-vectors [x,y,z] you represent them as 4-vectors [x,y,z,1], which allows you do do translations and projections easily).

I explain the math, but I'm not expert enough to talk about practical graphics topics like OpenGL / WebGL etc, so not sure how much further I can go. To merit the "NO BULLSHIT" label, it's really important that the author know the subject matter inside out ;)

[1] [https://minireference.com/static/excerpts/noBSguide2LA_previ...](https://minireference.com/static/excerpts/noBSguide2LA_preview.pdf#page=109)

<comment><USER14> Thanks! That looks good. I didn't mean any extensive chapter on OpenGL and the like, just some examples of linear algebra commonly used in computer graphics.

</comment></comment></comment></comment></comment><comment><USER15> As if other books on linear algebra have bullshit... This contributes to the "math sucks" culture. Math is fun an easy to learn. It just takes effort, like any other skill.

<comment><USER16> You may disagree but most books I read on math, or subjects that require math, contain a sizable amount of BS. Not in the sense of containing things that are wrong but in the sense of containing things that are there for the author to show off rather than for the reader to comprehend the subject matter.

I read books to learn about something that I didn't know about before. So I as a reader can't distinguish between the important stuff and the 'fluff'. The author has to do that for me. The best texts do that rigorously but the bulk does not, unfortunately.

</comment></comment><comment><USER17> The essence of linear algebra series on youtube is great as well. It provides a intuitive guide to what linear algebra is about in 2d and 3d space with "arrow" vectors with great animations. Once an intuition is provided about matrix transformations, determinants, basis changes and eigenvectors, then it explains how abstraction of this theory can allow carry over of these insights and techniques to other domains or other abstract vector spaces.

Too often learning starts at the abstracted level so intuition is lost in exchange for memorized techniques. There is a flip side of intuition-first techniques basically dumbing down everything into tweets but this video series is great at not doing that IMO.

</comment><comment><USER18> I own a physical copy of Savov's "No BS Guide to Math and Physics" and am very pleased with it. I found it particularly useful as a refresher on things I learned long ago, but no longer regularly use. The focus on practical application is of particular value in a quick reference role. I've also recommended it as a reference for students transitioning from a Technologist program to formal studies in Engineering. I've ordered this latest work just on the basis of that experience (and the recent specter of not remembering how to use eigenvectors when it come up in an obscure graphics problem).

</comment><comment><USER19> Just bought this. This book looks awesome — I'm working on some image processing this summer and I want to re-strengthen my Linear Algebra. It seems to be foundational for everything going on these days.

</comment><comment><USER20> Congrats Ivan, this was long in the making!

<comment><AUTHOR> Yeah, it seemed like it would never end. Thx for letting me use the vertical aspect ratio monitor... that helped a lot!

</comment></comment><comment><USER21> Ivan's books are always in my reference library. He is the Silvanus P Thompson of our modern day. Looking forward to reading Linear Algerbra and as always learning something new. Jjcona

</comment><comment><USER22> "concise, conversational tone" I wonder which it is. :-p

<comment><USER23> "Check this shit out:" in Section 1.1, page 9 of [https://minireference.com/static/excerpts/noBSguide2LA_previ...](https://minireference.com/static/excerpts/noBSguide2LA_preview.pdf)

<comment><USER22> It's actually pretty nice. I was mostly just being silly. But I do think concision is underrated, and some "conversational" tutorials drag on… Mathematicians end up with terse notation on purpose.

</comment></comment></comment><comment><USER24> I took a course in Computational Biology last semester and we covered all of a typical one semester linear algebra course in half the semester. It moved so fast that no one was really able to comprehend the material well enough, so I never felt like I actually learned the material as much as I was exposed to it and just understood its importance. I will definitely check this out as it may possibly be what I need to finally understand linear algebra. Thanks for all the hard work!

</comment><comment><USER25> The sample doesn't really give me a sense of whether this book is right for me. It contains a lot of material from the early chapters, but little of the parts of that confused me in college.

My primary question is whether this book is good at conveying the reasoning that promotes intuition around the more difficult (for me) topics, such as vector spaces and the many theorems associated with the Fundamental Theorem of LA?

If not, suggestions for other resources are very welcome!

</comment><comment><USER26> This looks fantastic! I'm a high school grad with a 2 year college degree but in college I took only a single math course (I was required to repeat Algebra 2 because my college didn't accept my high school's transcript for whatever reason) and I've felt behind from many of my peers not knowing enough "maths".

I need to brush up on my former knowledge and this look slike a great way to learn more!

</comment><comment><USER27> Ivan. in the refresher sections, after each section, for example, Complex Numbers, there is a list of sections in the example PDF, is this expanded in the real book or are they topics for further reading? I notice similar sections in earlier subjects seem to be expanded.

<comment><AUTHOR> Yes, all sections in the real book are expanded. The idea for the preview was to leave only the headings so that the table of contents will look the same.

<comment><USER27> Cool, picking up a copy now. I love the way it's written but unfortunately not safe to read to my kids as a bedtime story.

<comment><USER27> Wow, on demand shipping is fast. I already have it.

</comment></comment></comment></comment><comment><USER28> Just bought two copies, one for me and one for my son.

Nice textbook in Computer Modern just gets me all jazzed up. :)

</comment><comment><USER29> Great book that will fill a great void in a topic so fundamental for moving on to more advanced subjects.

</comment><comment><USER30> Please present one example of a linear algebra text which does contain "bullshit".

<comment><AUTHOR> You're right. Of all the mainstream textbooks on subjects for first-year science, linear algebra textbooks are the best of them all.

I guess the main "bullshit" I could reproach is the price tags, $60 -- $90, but even that is nothing compared to the textbooks for first-year calculus and mechanics that run $200+.

</comment></comment><comment><USER31> The extended previews and concept maps are a great idea.

</comment><comment><USER32> Good job Ivan, planning to purchase!

</comment><comment><USER33> Well done Ivan - I think I might purchase this :-)

</comment><comment><USER34> (1) Can work with any algebraic _field_. The greatest interest in practice is for the field the set of real numbers R. The set of complex numbers C can also be important. Curiously, there are some applications, say, error correcting codes, where the field is finite, e.g., the set of integers modulo a prime number.

For learning, I recommend working with the complex numbers C for where they do help, with very little extra effort, and let the real case be mostly a special case.

(2) The main motivation for linear algebra is just solving systems of simultaneous linear equations as in high school. The main solution technique is just the elementary row operations used as in Gauss elimination -- can learn that in three minutes and program it in 10.

(3) Matrix theory is central, even crucial, in linear algebra but really is just some darned convenient notation that can motivate just from solving a system of linear equations. So, for positive integers m and n, an _m x n matrix_ is a rectangular array of numbers (real, complex, other, as you have decided to work with) with m rows and n columns. So, it's just notation.

(4) The big deal about matrix theory is just that can multiply matrices. The multiplication is defined just so that a system of linear equations can be written as a product of (A) a matrix from the coefficients and (B)+ a matrix with one column of the unknowns set equal to a matrix of one column for the right hand side. Let's try it for some high school case of 2 equations in two unknowns (roughly as in TeX, and underscore character starts a subscript):

         a_11 x_1 _ a_12 x_2 = b_1

         a_21 x_1 _ a_22 x_2 = b_2

So, the 2 unknowns are x_1 and x_2.

                           / a_11  a_12 \
         2 x 2 A =  |                        |
                           \ a_21  a_22 /

                          / x_1 \
         2 x 1 x = |  x_2 |
                          \ x_3 /

and similarly for 1 x 1 b. Then the matrix multiplication Ax is _defined_ just so that we can write Ax = b and have that be equivalent to the 2 equations in 2 unknowns in the high school form above.

Commonly we write A = [a_ij] for i = 1, 2, ..., m and j = 1, 2, ..., n.

Now, we can do some arithmetic on the matrices, and that starts to get darned useful: E.g., for a number p we can define the product pA = [p a_ij]. So we multiply the matix A by the number (call it a _scalar_ if you want) p. And we can add two matrices: So for m x n A = [a_ij] and m x b B = [b_ij] we can define m x n C = A + B where C = [a_ij + b_ij]. So just add the corresponding _components_ (elements, entries).

Then presto, bingo, we get to why this subject is called _linear algebra_ : Given m x n A, n x 1 x, n x 1 y, and numbers p and q, we have

         A(px + qy) = (pAx) + (qAy)

which says that A is _linear_ or a _linear operator_ \-- in calculus, both differentiation and integration are also linear operators. There is a huge book _Linear Operators_ by Dunford and Schwartz, that is, _functional analysis_ , that is where the _points_ we are talking about, _analyzing_ , actually functions. So, biggie special cases are Hilbert space and Banach space. So, linearity in linear algebra is a biggie start on functional analysis.

Why care about linearity? Because its (A) simple, (B) permits powerful theorems fairly easy to prove, and (C) is an assumption that often holds quite well in applications in science and engineering.

The next biggie deal about matrix multiplication is that it's associative:

         (AB)C = A(BC)

and that property drives a lot in duality, game theory, matrix computations, error correcting coding theory, etc. Can write out a proof in terms of the i's and j's and, there, will see that the crucial step is being able to interchange the order of summation signs (which in calculus is the same as interchanging the order of integral signs which in more advanced parts of calculus is Fubini's theorem) when adding finitely many numbers but could also know that the result is true because A, B, and C are functions, function composition is essentially just matrix multiplication, and function composition is essentially obviously associative!

Given m x n matrix A with m = n, then A is _square_. If a_ij = a_ji, that is, if _reflect_ about the diagonal from upper left to lower right and get the same thing, the A is _symmetric_.

Now a biggie, IMHO the most important result in linear algebra: Regard

<comment><USER34> Mod: Please delete this post and its second copy. Both were posted while in draft and in error. I had to stop working on the post and just left the Web page without ever clicking on Submit, and somehow two copies got posted.

Maybe in the future I will complete the writing and post, but what is there now is incomplete and too rough. So, please delete.

</comment></comment><comment><USER34> (1) Can work with any algebraic _field_. The greatest interest in practice is for the field the set of real numbers R. The set of complex numbers C can also be important. Curiously, there are some applications, say, error correcting codes, where the field is finite, e.g., the set of integers modulo a prime number.

For learning, I recommend working with the complex numbers C for where they do help, with very little extra effort, and let the real case be mostly a special case.

(2) The main motivation for linear algebra is just solving systems of simultaneous linear equations as in high school. The main solution technique is just the elementary row operations used as in Gauss elimination -- can learn that in three minutes and program it in 10.

(3) Matrix theory is central, even crucial, in linear algebra but really is just some darned convenient notation that can motivate just from solving a system of linear equations. So, for positive integers m and n, an _m x n matrix_ is a rectangular array of numbers (real, complex, other, as you have decided to work with) with m rows and n columns. So, it's just notation.

(4) The big deal about matrix theory is just that can multiply matrices. The multiplication is defined just so that a system of linear equations can be written as a product of (A) a matrix from the coefficients and (B)+ a matrix with one column of the unknowns set equal to a matrix of one column for the right hand side. Let's try it for some high school case of 2 equations in two unknowns (roughly as in TeX, and underscore character starts a subscript):

         a_11 x_1 _ a_12 x_2 = b_1

         a_21 x_1 _ a_22 x_2 = b_2

So, the 2 unknowns are x_1 and x_2.

                           / a_11  a_12 \
         2 x 2 A =  |                        |
                           \ a_21  a_22 /

                          / x_1 \
         2 x 1 x = |  x_2 |
                          \ x_3 /

and similarly for 1 x 1 b. Then the matrix multiplication Ax is _defined_ just so that we can write Ax = b and have that be equivalent to the 2 equations in 2 unknowns in the high school form above.

Commonly we write A = [a_ij] for i = 1, 2, ..., m and j = 1, 2, ..., n.

Now, we can do some arithmetic on the matrices, and that starts to get darned useful: E.g., for a number p we can define the product pA = [p a_ij]. So we multiply the matix A by the number (call it a _scalar_ if you want) p. And we can add two matrices: So for m x n A = [a_ij] and m x b B = [b_ij] we can define m x n C = A + B where C = [a_ij + b_ij]. So just add the corresponding _components_ (elements, entries).

Then presto, bingo, we get to why this subject is called _linear algebra_ : Given m x n A, n x 1 x, n x 1 y, and numbers p and q, we have

         A(px + qy) = (pAx) + (qAy)

which says that A is _linear_ or a _linear operator_ \-- in calculus, both differentiation and integration are also linear operators. There is a huge book _Linear Operators_ by Dunford and Schwartz, that is, _functional analysis_ , that is where the _points_ we are talking about, _analyzing_ , actually functions. So, biggie special cases are Hilbert space and Banach space. So, linearity in linear algebra is a biggie start on functional analysis.

Why care about linearity? Because its (A) simple, (B) permits powerful theorems fairly easy to prove, and (C) is an assumption that often holds quite well in applications in science and engineering.

The next biggie deal about matrix multiplication is that it's associative:</comment>


I'm giving up on business. Here's why - <AUTHOR> http://www.bradcypert.com/today-im-giving-up-business/

<comment><USER2> MVP/idea-validation is for ideas that require a lot of investment before they are any use - needing, say, manufacturing, R&D, partners. But many, _many_ ideas, especially software, can start really small, and be of real use immediately.

Richard Dawkins has this nice chapter called _" do good by stealth"_, which is about how complex features like eyes and orchids can evolve in small increments, each step giving a survival advantage... ie being useful.

Some would argue timebeard.com _is_ a MVP, and you got data. Some would say it's version 0.1. It's both.

<comment><AUTHOR> I completely agree with you! I didn't call it an MVP until release, I always referred to it as "Version 1", but in reality, they're both the same thing.</comment></comment>


R = 1 – sin(θ) (A Love Song) - <AUTHOR> http://www.velvetcache.org/2010/06/16/r-1-sin-theta

<comment><AUTHOR> I'm sure I'm not the only programmer who also loves music. Thought I would share a song I wrote, inspired by an XKCD strip.

</comment><comment><USER2> It's great! The music isn't the kind of thing I could listen to very much, but I like the idea.</comment>


A Peek into Einstein's Zurich Notebook - <AUTHOR> http://www.pitt.edu/~jdnorton/Goodies/Zurich_Notebook/index.html

<comment><USER2> As someone studying physics at the moment, this is a great re-energizing force. Incredible to see that Einstein wrote the same equations, and (mostly) in the same notation that we use today. Humbled.

</comment><comment><USER3> It looks like John D. Norton has a thing about Einstein: [http://www.pitt.edu/~jdnorton/Goodies/](http://www.pitt.edu/~jdnorton/Goodies/)

<comment><USER4> I took his class last semester called "Einstein for Everyone" at the University of Pittsburgh. I'd call him a fanatic

</comment></comment><comment><USER5> Cool stuff</comment>


HP is trying to patent continuous delivery - <AUTHOR> http://blog.matthewskelton.net/2015/03/06/hp-is-trying-to-patent-continuous-delivery-here-is-how-you-can-help-block-this-madness/

<comment><USER2> It's the way the patent system works. You file obscene numbers of unenforcable patents for the sake of mutually-assured destruction should a patent war come up.

Most patents have massive amounts of prior art, are obvious, or otherwise unenforcable. But if you threaten a patent lawsuit against me, either:

1\. You can put me out of business

2\. I have my own warchest of 1000 patents. I find 30 your're breaking. They're all bunk, but it gives enough uncertainty that I might be able to put you out of business that you don't sue.

Employees at companies have to go along with it to keep their jobs. I have a big problem with vilifying and blaming them the way this article does. Not everyone has to share your sense of ethics to be a good person.

Big companies are only slightly more to blame -- they have to do it to survive. In addition, I'd still rather see these patents with HP than with a little company in East Texas.

The problem is the patent system itself. We need reform it. The way it is set up, frivolous patents like these are (1) necessary and (2) draining the lifeblood of America.

The problem also comes in around enforcement. HP is unlikely to sue a free software project. I honestly believe that they intend to treat the patents as mostly defensive. But HP isn't doing so hot on R&D, and the odds of the patents going to a complete patent troll in the next 20 years are maybe 10%. There are dozens of companies like HP.

</comment><comment><USER3> I'm not an expert on patents. If nobody noticed it and it was successfully granted, can it be revoked in the future due to "not originally invented"?

<comment><USER4> Patents can be challenged/revoked if they are not novel - in other words, if the practice, process, invention, etc already existed. Particularly if it is in widespread use it is often easier to get it revoked - hence conference papers, articles, posts, etc, about this practice can prove that CD is well known and get the patents taken care of.

Generally you are not required to search for prior art before you file a patent, you just have to promise you aren't aware of any. Some people intentionally avoid looking for prior art for this reason, as the patent office is overwhelmed and often staffed people not as much of experts as they should be, and you end up with people granting patents for obviously non-novel things.

</comment></comment><comment><USER5> HP makes such crummy software, I can't believe they actually test anything.

<comment><USER6> And they don't want anyone else to either.

<comment><USER7> It makes them look bad.

</comment></comment></comment><comment><USER8> Looking through LinkedIn it seems these guys are all Israelis. Maybe that's why they don't care about gaming the US patent system.

<comment><USER9> That's because they all work for the R&D group that HP acquired in 2007 when they bought Mercury. The couple names I recognize on that list have worked on products like LoadRunner and RUM</comment></comment>


Town Introduces its own Currency - <AUTHOR> http://www.bloomberg.com/apps/news?pid=newsarchive&sid=aq6uUiFX9_ZM

<comment><USER2> I heard about this a month or so ago on NPR. I don't see the benefit in it really. Unless they can back their currency with gold or something else it will continue to fluctuate in value with the pound.

Furthermore I can't see why people would really want to have this town's currency other than as a collectors item. You can only spend it in this particular town, and not even at all of the businesses there.

It's been said that this will help keep business (money) in town. Meaning that locals will be more likely (forced) to spend money at local businesses if they have the local currency. But why would anyone want to restrict themselves like this as a shopper? What's to stop them for refusing to accept change in the local currency or to trade it in at the bank for official British currency?

<comment><USER3> I agree. Can someone explain how this currency which is tied to Sterling protect people from the devaluation of Sterling?

</comment></comment><comment><USER4> I was there last night. At the launch you could buy L£22 for £20. Local traders are offering incentives, such as discounts if you pay in L£.

It doesn't force anyone to spend their money locally, because you can always trade your L£ for sterling. It's more like a constant reminder and a helpful system for keeping money in the local economy.

Income in L£ is counted as sterling as far as the tax man is concerned. Stewart Wallis of the NEF mentioned a local currency scheme in Australia where the taxes could be paid in local currency. Of course when it came time to spend it it could only be spent locally. So they re-roofed the community centre.

There's a web site here: <http://www.thelewespound.org/>

</comment><comment><USER5> I once had the idea for my own "personal currency"... I would set the exchange rate... For some reason it didn't really catch on.

The article alludes to it, but in the UK, legal tender is a bit sketchy at best: [http://en.wikipedia.org/wiki/Legal_tender#In_the_United_King...](http://en.wikipedia.org/wiki/Legal_tender#In_the_United_Kingdom)

The reality of this really comes home when you try to spend your Scottish Pounds in England (I got caught by this first time I went to Scotland).

Of course, the counter-example is the Euro - which the participating countries seem to grumble about a bit (it's blamed for inflating some prices)... but as a tourist it's a godsend.

<comment><AUTHOR> I think the reason it's frowned upon is due to tax evasion reasons. Imagine paying your employees in this town's currency and then having them spend it within the town.

<comment><USER2> I'm not quite sure I follow your reasoning here. How does paying your employees in the town's currency allow tax evasion? You would still have to report paying them the money.

You could pay them under the table (not report it to the government) in cold hard cash using the British pound just as easily as using a local currency. I can't see how using a local currency would make it any easier.

<comment><AUTHOR> I guess the point is that it's easy to not report when you are dealing with the town's currency.

If you take it to the extreme and consider a barter system. I can be a farmer and give a few tomatoes to the barber who cuts my hair. The government does not know what happened and you do not report the income as earned.

You are right that it's identical to paying under the table but I think there is a higher incentive to do that with these town currencies.

Thanks for making me rethink my logic.

<comment><USER6> Which is perfect, barter works, fuck the government and their theft of your income.

<comment><USER5> This is exactly the idea behind BarterCard <http://www.bartercard.com/>

</comment></comment></comment></comment></comment></comment><comment><USER7> <http://en.wikipedia.org/wiki/Ithaca_Hours>

<comment><USER8> Ha, I was just coming to post that. On a related note:

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

</comment></comment><comment><USER9> I read an interesting article in the paper the other week about Zimbabwe, where the Z$ has been inflated so vastly that it is valueless for all practical purposes.

The government there have started to ration petrol and issue vouchers entitling the holder to 20 litres of the stuff. People started to swap these vouchers between themselves for other goods and services, and in many areas of the black market petrol vouchers are approaching the status of a de facto currency. Instead of a loaf of bread costing Z$6 billion or something, it'll cost you two litres of petrol.

It has fascinating implications--because the official currency is backed by nothing and is now meaningless, these bits of paper backed by a tangible quantity of a valuable commodity (ie. petrol) have effectively become their own currency. People are trading them with no intention of redeeming them for petrol, in the same way as you'd never go and ask for £10 of gold for your tenner. Perhaps something inventive like this would be a better way of running these town currencies than simply pegging them to the pound.

</comment><comment><USER10> Statements like "Totnes, a town of about 8,000 people" and "In Totnes, there are about 5,000 notes in circulation" suggest to me this is no more than a gimmick. Even as a local currency it can't work.</comment>


Hundreds of active and former US police officers are part of extremist FB groups - <AUTHOR> https://www.theverge.com/2019/6/14/18679598/facebook-hate-groups-law-enforcement-police-officers-racism-islamaphobia <comment><USER2> Controversial, but couldn't you make this claim about almost any profession with a decent number of practitioners and any sort of responsibility?

Probably about any political side or extreme outgroup too.

There are likely at least a million police officers in the US, so hundreds of those being associated with questionable Facebook groups hardly seems like it'd be statistically relevant. And you could probably swap police officers with teachers, doctors, lawyers, politicians or military personnel and find similar figures.

</comment><comment><USER3> I see the astroturf committee is out in force already.

TFA said their match got 14000 hits, and they called police and sheriffs' offices and confirmed 400. But how many did they call about? Were they randomly selected, or were the ones called about identified as more likely than others?

We know that these domestic terrorist groups encourage members to join and try to subvert police departments and border patrol offices, and we know that the presence of just one has been seen to profoundly increase the amount of brutality in a department.

</comment><comment><USER4> Lots of innuendo here, but that's about it. How many former police are members of the Democrat party? Would that be news?</comment>


The Future of Wind Turbines: No Blades - <AUTHOR> http://www.wired.com/2015/05/future-wind-turbines-no-blades/?mbid=social_fb

<comment><USER3> OK, so: Betz's Law says that the maximum energy that any wind turbine can extract is 16/27 of the kinetic energy contained in the wind that it blocks. Modern three-blade wind turbines reach 75-80% of the theoretical maximum, across the entire area their rotors sweep out.[1]

That's why the classic windmill design is so classic: its efficiency scales with the _square_ of the length of the rotors. The energy extracted by a windmill is (very roughly):

        wind_speed * 16/27 * 0.8 * π * rotor_length^2

But then the wind speed also increases with height.[2] So the game to design an efficient windmill is to sweep out as much cross-sectional area as possible, as high up in the air as possible, and that's how we get the iconic windmills we have.

I don't know anything about anything -- I just read this stuff on Wikipedia. But until a third-party engineer says otherwise, I'm super skeptical that a device like this with minimal high-altitude cross-section is anywhere in the game.

[1] [http://en.wikipedia.org/wiki/Betz%27s_law](http://en.wikipedia.org/wiki/Betz%27s_law) [2] [http://en.wikipedia.org/wiki/Wind_profile_power_law](http://en.wikipedia.org/wiki/Wind_profile_power_law)

<comment><USER4> My first thought was "even if this is less efficient, the silence and lack-of- bird-killing means it would be viable to install places where NIMBYism etc. mean that traditional turbines can't be".

i.e. it may be sufficiently in the game to compete effectively against "no turbines" even if it can't compete against turbines directly.

<comment><USER5> It also seems like you'd be able to fit more of them into the same space. The company also claims that they're (allegedly) cheaper to manufacture and are (allegedly) cheaper to maintain. Even if the efficiency is less than those of a traditional windmill, it would still make sense to use them from a cost savings perspective alone.

That's if everything the company claims is true. Too many other alternative energy companies have made similar claims and failed to follow through for me to take this with anything other than a grain of salt.

edited for clarity.

</comment></comment></comment><comment><USER6> Substantial discussion of the concept and technology over here:

[https://news.ycombinator.com/item?id=9523877](https://news.ycombinator.com/item?id=9523877)

</comment><comment><USER7> I followed the debate about renewables for quite some time and I heared stories like this before. A new design for wind energy with so obvious advantages. And you can read pretty similar stories for new solar or water power tech also pretty regularly.

I remember that already in the 90s I heared people saying that future wind turbines will have a funnel to focus the energy. Later kite-like flying turbines or turbines in donut-shaped balloons became a thing.

But wind turbines still basically look very similar than they used to be all the time, the biggest change is that they became much bigger. There's a reason for that: The design worked well and has been improved in details over the years. It's much easier to improve in small steps than to reinvent a completely new tech, which will have many downsides that the enthusiasts inventing them don't want to see.

That's not saying that it's entirely impossible that a completely new design of wind turbines will some day emerge. But I don't think it's very likely. And before I believe it I want to see them built at scale for a reasonable price. (Because one of the biggest advantages of the existing wind turbines - <USER2> from them being environmentally friendly - is that their price dropped rapidly in the past years.)

</comment><comment><USER8> Similar to the windbelt:

[http://www.instructables.com/id/Windbelt-Redux--21st- Century...](http://www.instructables.com/id/Windbelt-Redux--21st-Century- Micro-Power-Generatio/)

Fluids tend to move as vortices so often reciprocating motion can be at least as efficient as rotary motion. For example it is (currently) difficult to replicate the efficiency of birds and fish with propellers.

Potentially (ahem) it's possible to extract work from ions in a flow, and if it's laminar there would be no vortex losses. Just for fun, here is an electrostatic turbine, which works a bit like an electrohydrodynamic (EHD) drive but in reverse. From what I understand, it's difficult to extract more work than it takes to ionize the fluid, so this cheats a bit by using liquid droplets:

[http://www.wired.co.uk/news/archive/2013-04/3/bladeless- wind...](http://www.wired.co.uk/news/archive/2013-04/3/bladeless-wind-turbine- ewicon)

</comment><comment><USER9> I personally like the idea of wind turbines being tethered high-altitude blimps.

I assume the high-altitude ones could be higher than birds fly.

They could even be used as in-flight recharge stations for drones.

<comment><USER10> It's amazing how high birds can fly [http://en.wikipedia.org/wiki/List_of_birds_by_flight_heights](http://en.wikipedia.org/wiki/List_of_birds_by_flight_heights)

<comment><USER9> Unfortunately it's likely that many many types of animals take advantage of low-altitude wind-streams, especially during migrations.

But maybe we could place several of them into the jet-stream (at 10-15 km) which is higher than all birds except one type of vulture.

Edit: Nevermind, Google is working on exactly that: [http://www.gizmag.com/google-x-makani-power-airborne-wind- tu...](http://www.gizmag.com/google-x-makani-power-airborne-wind- turbine/27668/)

The cable seems to be the most difficult part: [http://en.wikipedia.org/wiki/High- altitude_wind_power](http://en.wikipedia.org/wiki/High-altitude_wind_power)

</comment></comment></comment><comment><USER11> I find myself thinking of a grassy field swaying in the wind.

I wonder if they should try painting them deep green or something.</comment>


Why Standard Time Is Better - <AUTHOR> https://medium.com/@herf/why-standard-time-is-better-e586b500923 <comment><USER2>
      California, Florida, and the entire EU have begun doing away with the time change.

California has done no such thing. All California did was strip out the old statute language from 1949 that wasn't being followed anyway. Federal law changes would be required for CA to deviate existing practice.</comment>


Label Schema: A New Standard Approach to Container Metadata - <AUTHOR> http://thenewstack.io/label-schema-launches-provide-standard-approach-container-metadata/ <comment><AUTHOR> RC1 of the Label Schema spec was just announced by Gareth Rushgrove of Puppet at the Container Camp conference in London. The spec is a community effort from multiple companies including Puppet, Mesosphere, Microscaling Systems and Container Solutions.

The spec is a release candidate so we'd like to get as much feedback as possible from the community. Here is a good place to discuss it but please also send feedback to the Label Schema mailing list.</comment>


HTML5 Canvas Experiment - <AUTHOR> http://9elements.com/io/?p=153

<comment><USER2> I wonder how "live" the data is? It's seriously fun to sit and just watch.

<comment><USER3> Those are tweets if u click on the particles u will see the tweets

</comment></comment><comment><USER4> I'm using IE 6 and don't see nothin'

<comment><USER5> no need to include the version number

</comment></comment><comment><USER6> That is awesome. I like the particle engine</comment>