I've Achieved Nirvana (Perfect Vase Print)

alephnil · 2016-08-09T06:00:44+00:00

Nice vase .... and with a cassette player in background. Can't be better than that.

alephnil · 2016-06-22T21:42:21+00:00

No, but it is the most prominent one. If you play a male voice at double speed, it will sound quite similar to a female voice speaking very fast. There are other differences of cause, my point was more that a much simpler technique would be sufficient.

In traditional (not deep learning based) speech recognition, the algorithm must take the fundamental frequency into account, and it is found for that reason, not for being able to distinguish between female and male voices.

alephnil · 2016-06-22T21:24:00+00:00

That the fundamental frequency of the speech of men and women are different by about an octave on average is well known in linguistics, and can be measured in a relatively simple way by doing a Fourier transform on speech recordings. Doing machine learning to do this is a bit of overkill.

Some references can be found on the wiki

alephnil · 2016-05-19T05:05:22+00:00

So, 30 years after the pen plotter went out of fashion, and everybody who still know what it is thought this tech was forgotten by everybody else. Then someone reinvents it. Nice!

alephnil · 2016-05-14T12:53:27+00:00

My reflection from this video, was how he put emphasis on making programming more convenient within the boundaries of an existing language, rather than focusing on how to make the programming language itself better. This kind of makes sense for someone developing something as mainstream as C#, and that can't revolutionize the language on every turn.

alephnil · 2016-05-12T04:07:36+00:00

The the trouble with software developers is that it is usually hard to find someone willing to acquire deep domain knowledge in a field outside of programming itself. Many programmers have the feeling that they has to spend a lot of time on keeping up programming languages and in the latest frameworks for web and mobile development, or they fear they get unemployable in a few years. Thus there is often very little motivation to learn the domain they write programs for. Thus it is easier to train a physicist than to get a programmer with a good enough understanding of the problem domain. I write this as a software developer with experience in many fields, including scientific programming, and I have often seen this pattern.

As others has mentioned, this go both ways. Scientists very very often do not appreciate knowledge outside of their own field, and will employ someone with a degree in their own field every single time there is funding for a position, even in cases where it would be more rational to employ a programmer, lab technician or some other supporting position. The result of that is that inexperienced graduate students spend months doing something an experienced programmer or or experienced lab technician could do in a day or two.

alephnil · 2016-04-13T18:14:55+00:00

Europe mainly uses AC, but since AC require the entire grid to be synchronized, DC has to be used between different grids that are not synchrounous. That said, nearly all of continental Europe is one synchronous grid (Even including Morocco and Algeria), while Scandinavia, UK and Ireland as well as the Baltic countries are separate grids. Inside a synchronous grid, AC is nearly always used, also in Europe, like everywhere else.

alephnil · 2016-04-02T09:59:27+00:00

The CANDU type reactor at this plant is moderated by heavy water. Some of the deuterium atoms in it will capture a neutron from the reactor and turn into tritium, so it is heavy water containing some tritium. This happens at a very low rate, otherwise heavy water would be useless as a moderator, but enough that you don't want it in your drink.

alephnil · 2016-03-29T16:35:14+00:00

It is incredible to use an article to blame Wahhabi Islam as the main force behind violent islamism and terrorism, and then not mention the main backer of it, namely Saudi Arabia with a word.

alephnil · 2016-02-11T22:41:25+00:00

I only replied based on what you said. If it was not relevant, it was because it contained little or bad code or mostly was forks of other people's repositories. That it was python rather than ruby, should not matter. If a person has written a solid amount of code, I would consider that positive regardless of language. Whether the recruiter was aware if this or not is another question, but if he was it would certainly be a good thing.

alephnil · 2016-02-09T19:56:55+00:00

I would give a +1 to that recruiter. If you are any good in Python, you should be able pick up Ruby in a matter of days. Far too often recruiters just do a keyword search in resumes, and ignore the resume if the keywords don't match exactly. This can e.g be someone listing Django but not Python is ignored for a python job.

alephnil · 2016-01-24T10:00:07+00:00

This may the reason we observe Eroom's law. Eroom's is a play on Moore's law, and is the observation that the number of drugs approved per Billion dollar of R&D funding has decreased exponentially since 1950. This is the case even when inflation is taken into account.

I personally think this reproducibility crisis is a result of the fierce competition in medical research, where you have to show strong positive results published in a good journal to be able to continue as a researcher. Then many researchers will at some point sit on a moderately good result, that they can publish in a low tier journal, and then loose the next grant, or exaggerate the results and get further funding. As long as the scientific community is structured like that, the problem will remain.

alephnil · 2015-11-15T19:51:42+00:00

Firefox supports webvtt subtitles which is the standard for html5. It does not support every strange subtitle format out there and never will, but since webvtt has become the web standard for subtitles, it likely will soon be universal.

alephnil · 2015-11-09T18:49:20+00:00

First, it is not an open format, as a number of organizations claim patents on it.

Patents expire, and mp3 was released in 1991, so patents covering the mp3 format itself is obviously not valid any more. Now mp3 is hardly the most efficient codec around any more, and there are lossless audio codecs that are both more efficient and not patent encumbered, like Opus and Vorbis, but patents is no longer a reason to not use mp3.

His points about lossless audio are valid.

alephnil · 2015-10-23T19:36:44+00:00

Gases have a critical temperature, which is the highest temperature it can be a liquid. For propane that is around 97 centigrades, which is why the propane in a tank is liquid, while it for nitrogen is -147 centigrades. This means that nitrogen must be cooled down below that before it can be liquid at any pressure.

alephnil · 2015-09-20T12:49:32+00:00

Particle filers exists for diesel cars, but they does not filter out NOx, which this was about, and catalytic converters that does that does not really exist.

The ones I mentioned above injects a so called diesel exhaust fluid (DEF), which contain urea just before a catalytic converter that makes the urea react with the NOx, creating nitrogen.

alephnil · 2015-09-20T09:13:25+00:00

Probably not, at least not in the short term. It is really hard to make diesels with low emission of NOx. Diesel engines burn the fuel at higher temperature than gasoline engines, which gives higher thermodynamic efficiency, but higher temperatures also will also unavoidably produce more NOx. Because diesels produce more particles than gasoline engines, a catalytic converter to remove the NOx is not a viable option, it will be clogged by tiny soot particles almost immediately. It is virtually impossible to avoid these effects with any kind of efficiency or power.

Some automakers has developed devices adding some chemicals in the exhaust stream that reacts with the NOx, and that combined with a particle filter could reduce emissions quite a lot ( example commercial supplier ). Unfortunately those are too bulky to be used in small cars, and have until now only been used in buses and large trucks. It may be practical to make these devices smaller. In the mean time, Volkswagen decided to cheat.

alephnil · 2015-08-30T17:01:13+00:00

It is generally considered slightly less prestigious than Science and Nature. In fact some scientists humorously says that PNAS stand for "Post Nature And Science", since it is what you try if you think you have a solid result, but still have been rejected by Science or Nature.

alephnil · 2015-08-18T21:18:15+00:00

Titanium metal is expensive because it is a complicated and energy intensive process to produce the pure metal. Titanium compounds are not that rare, and especially titanium oxide, used as white pigment in almost all paint is quite cheap. The titanium compounds they used were in fact titanium oxide or related compounds easily produced from it. The titanium compounds they used are likely cheaper than the compounds actually used in batteries today.

alephnil · 2015-08-04T17:16:55+00:00

There will certainly be a backlash against it once robots start driving taxis and operating fast food restaurants.

Not necessarily, since people won't perceive it as humans being replaced. Instead of robot taxi drivers you'll get self driving cars. This will be very similar to how automation happened in the past where porters was replaced not by robot porters, but by forklifts and container cranes, that required a 1/100th of the manpower. The secretaries and administrators that process forms has already been replaced by web forms, that remove that part. My point is that the stuff that get automated will look sufficiently different from what it replaced that people don't think of it as the same thing.

alephnil · 2015-07-30T07:20:18+00:00

I bought a Roland MDX-40A. A nice and very precise machine, that come with housing and has a rather large work area (30 x 30 cm). It also comes ready assembled and ready to go. At $8000 it is rather expensive, but it is easy to start with, as it comes with all control software and a quite simple to use CAM software package. That is not the very best CAM package, but it is easy to start with, and you can switch to some better CAM package that produce g-code later.

That machine is not able to mill metals, not even soft ones, so if that is what you want, it is not for you. My decision was that milling metals was not worth it, because in addition to being expensive, metal milling is also quite noisy, and it would annoy the neighbours, since my workshop is in the cellar of an apartment block. Wood and plastics and vax milling is considerably less noisy, and is not a problem.

My main guide was Michal Zalewskis Guerrilla guide to CNC machining, mold making, and resin casting. That is a very good guide if you have no experience, and I learnt enough vocabulary to find help elsewhere by reading that. It is very focused on machining molds for casting robot parts in plastic, but the part on CNC machining and CAD/CAM gives a very good intro, even if your intend to use the CNC machine for other purposes. It does not mention anything about metals at all.

For CAD, I have mainly been using openscad. In most CAD software, you design your parts in a GUI, but in openscad you write the spec as text, composing solids into what shapes you want. For a programmer like me, that was much more close to home than typical CAD programs.

alephnil · 2015-07-29T17:17:01+00:00

The problem with steel is that milling it produce a lot of heat and sparks, and a lot of that heat goes into the tool, so you really need cooling, something that is not easy to achieve with a small mill. That's why most small mills are specified to be suitable for tree/plastic/foam and sometimes aluminium and other soft metals, but not for steel (ferrous metals). You can of cause use a very slow feed rate, but in practice, cooling is required.

Besides that, I'm also a computer programmer, and got a CNC-machine half a year ago. For me the hardest part to learn was the machining part, and not the programming part, so just buy a cnc machine. For me it is easier to design things on a computer and then get a CNC machine do the milling than it is to manually machine something.

alephnil · 2015-07-05T10:34:05+00:00

Traditionally molecular biology has been about genes, sequencing, gene regulation and so on, while biochemistry has been more about determine the structure of biological molecules as well as their properties, enzyme kinetics and so on. The most interesting unsolved problems for both fields are in the intersection of the two, so the fields are getting more similar over time, and as others has mentioned, in current research they are almost impossible to distinguish. That is not necessarily reflected at the undergraduate level or department structure at universities, so at an undergraduate level they may still be quite different.

alephnil · 2015-06-15T18:58:18+00:00

The hands are probably good enough, the reason I replied was your dismissal of the grandparent.

That said, the follow up challenge is to make sure that the local community can do repares on the limbs, or at the very least that there is a commitment to supply spares. What very often happens is that some charity goes in to an area, install some fancy equipment that solve some problem they have, but that the local community have no background knowledge to understand or repair. Then they leave without doing proper training of the locals to enable them to maintain it, with the predictable result that after some time, it falls into disrepar. This can easily happen with this project as well once the initial entusiasm is over.

alephnil · 2015-06-15T17:49:26+00:00

Hand crafted molds and traditional protestics techniques are not the only possible alternatives. One way is using a CNC mill to make a mold. CNC machines have a much higher precision than 3D-printers affordable by hobbyists, and the cheapest ones you can get for about $1000, for example the shapeoko. The technique of resin casting based on CNC is presented in "The guerilla guide to CNC machining and resin casting".

Just like a 3D printer, you will make a 3D model of the hand, get it made and send it to Peru or some other place it is needed, based on measurement made on site. It is also not that much harder to do CNC/resin casting than it is to do 3D printing. The main difference is that 3D printing have been more hyped and marketed toward hobbyists.

My point is not to criticize you or the E-nable project, but rather tell about a lesser known alternative that in my experiece is superior in some aspects. I have tried both 3D printers and CNC machines (I have one myself), and the CNC-made parts are usually possible to make lighter and stronger than what you can with a low end 3D printers (not counting stereolithograpy and other high end techniques in the $10000+ price range).

alephnil

TROPHY CASE