jwm's comments

jwm | 13 years ago | on: Increasing wireless network speed by 1000%, by replacing packets with algebra

This could be demo'd very easily by gluing together:

udpcast (http://www.udpcast.linux.lu/satellite.html) -> Sends/receives files over UDP. Supports FEC.

netcat -> Join file I/O (from udpcast) to local TCP/UDP sockets

openvpn / iptables userspace -> Provide connection routing.

Seems like an evenings work.

Edit: udpcast might not be suitable for this. I am surprised noone has already built a simple UDP FEC tunnel program...

jwm | 13 years ago | on: A Generation Lost in the Bazaar

> Fourth: Related to point two really: A lot of you seem to have little actual ambition of making things better, I guess that is what happens if you grow up in a bazaar and never even experience a cathedral. I pity you.

I think people do want to make things better, but its happening much more decentralized, with small teams taking small safe steps on tools, libraries & frameworks.

Media, on-line banking, 3d printing, accessible hardware hacking, e-commerce sites, scientific/engineering software. The majority of these things are made by small teams plugging the best libraries and platforms out there together, where they already solves part of their software problem. Android, Cloud, Linux etc. It would be silly to say these were without ambition and don't contribute to the community.

(The average software devs Impact Factor may be diluted by the increasing number of people working with computers, but computers are so globally useful its inevitable. If good things are still getting made then who cares.)

jwm | 13 years ago | on: Things I do to be consistently happy

How do you find this kind of routine meshes with the sleeping patterns of your social circle? I've always been interested in trying something like this, just to see what it's like.

jwm | 13 years ago | on: Wikipedia Redefined

I agree. Websites that do this are awful, Google Plus is guilty of this.

Re combo-boxing the language list: Wikipedia is the most successful multi-language website by far. Highlighting this to new and old users is a great thing. Its not like the search box takes up any more than one line anyway.

For Wikipedia, this redesign blows. I do like the visual style though. This is really just showcasing the webdesign company's talent, right?

jwm | 13 years ago | on: Python for iOS

Though I do agree about BlackBerrys consumer prospects, any business with a few thousand deployments will probably be interested. Python+Qt look like a nice combination for rapid 'app' development.

jwm | 13 years ago | on: How Google handle leap seconds

From the Wikipedia article on Leap Seconds:

> Because the Earth's rotation speed varies in response to climatic and geological events, UTC leap seconds are irregularly spaced and unpredictable. Insertion of each UTC leap second is usually decided about six months in advance by the International Earth Rotation and Reference Systems Service (IERS)

I don't see how applications could make unix second <-> day conversions without downloading a map from the IERS, if leap seconds were included.

jwm | 14 years ago | on: Wind Turbine Makes 1,000 Liters Of Clean Water A Day In The Desert

It seems they are quoting an article from rechargenews.com [1] which erroneously adds this "steam before condensation" stage.

Reading the skimpy tech specs of the "WMS1000 Wind Turbine" from the company itself [2], it only lists the following stages:

Energy production -> Ambient air suction -> Humid air condensation -> Water production -> Water purification -> Pure drinking water distribution

----

Ensuring the water is airborne pathogen free would be a big issue for me which I am sure they must have thought of.

"Eole chief executive Marc Parent dreamed up the concept in the 1990s while working as an engineer in the Caribbean, where he had been reducing his bottled water costs by siphoning the condensation from his air conditioner."

I hope he boiled this water here first. This is the exact method used by new airborne pathogen detectors to collect virus and bacteria samples :/

[1]: http://www.rechargenews.com/business_area/innovation/article...

[2]: http://www.eolewater.com/gb/our-products/range.html

jwm | 14 years ago | on: Zeitgeist 2011: How the World Searched

I enjoy looking at these trends every year, but what a painfully designed website. Does this really need to be an overkill javascript "Web application" for what can easily be rendered as a few static pages of lists and facts?

And sheesh, look at that huge amount of space wasted by those persistent top and bottom grey and blue bars. My 1280x800 laptop screen is already constrained enough on the Y axis as it is. The site sure does look modern though. </old man web3.0 rant>

jwm | 14 years ago | on: Ubuntu 12.04 LTS to get extra-long desktop support cycle

I don't know too much about how the Canonical maintenance process works, but I imagine for all the server packages maintainers have to backport all new security and bug patches that come out to the package versions in the LTS releases.

It would follow that doing this for all the desktop packages would be extra work.

jwm | 14 years ago | on: University of California teachers’ union aims to block online classes

People here may be interested in this.

"Creativity in Mathematics, pt. 1 of 3, Inquiry-Based Learning (IBL) and the Moore Method" http://www.youtube.com/watch?v=RLVTV-vXJBg

I think its relevant in the current debate of the different learning styles: Physical presence lecturing, Long-distance lecturing, Class participation, Team problem solving, Individual problem solving, Individual rote learning.

If anyone has any studies comparing the end result problem solving ability of students who have gone through all the different combinations of the above learning styles, I would love to see them.

jwm | 15 years ago | on: The Pirate Bay: “The Battle of Internets is About to Begin”

Fascinating, and interesting similarities.

I did not know much about Usenet, so I went to the Wikipedia page and found this:

ISP-operated Usenet servers frequently block access to all alt.binaries. groups to both reduce network traffic and to avoid related legal issues.

This was the case years ago on the old news.iol.ie server; forgot all about it till now. That whole http://en.wikipedia.org/wiki/Usenet#Legal_issues section is quite interesting in light of the above; a recommended short read.

--

In general it seems that the network on which any system runs is pretty vulnerable to legal challenges. If not the ISPs, then maybe those pesky fibre and copper owners between them, for aiding and abetting copyright theft! Or maybe the ISPs might be coerced to only permit "Accepted" packet formats (ie inspect-able) to be used.

So far ISPs seem to not be caving in too quickly, but there have been some awful exceptions: the recent DNS seizures in the US, and a little closer to home our backbone-less Eircom being the only ISP in Europe to cave into the demand a few years ago to block access to piratebay.org (ex govt, careful).

However I shudder at the idea of a seperate darknet, it just seems so... unnecessary! Not to mention: "What are you doing honey?" "Oh I'm connecting to the Darknet." "Gee, isint that for pirates, hackers and perverts?". Though the ability for the common Jane to download mp3's and movies on it might have everyone secretly supporting it... hmm. I can only wonder at what the Internet will look like in 20 years time.

Personally I hope we all get UN mandated rules for unregulated Internet - China, North Korea and Iran being some of the leading examples for why this is so important.

jwm | 15 years ago | on: Congress Bans Some Scientific Collaboration with China, Citing Espionage Risk

equipping China with the skilled professionals it needs to produce the weapons of war to threaten the free world.

Do you think they really need technology? They have a population of plus one billion, and the strongest industrial capacity in the world plus just enough oil reserves. If they wanted to go to war, they could already very well do so as is and cause a really big bloody mess.

Look at Iraq, Vietnam, Afghanistan. All of us mistakenly believed the US's "superior technology" would make those missions a cakewalk. Technology doesn't win wars. People do. People we can reach.

And its not Germany vs France at the opening of WWII anymore. China already have machine guns, tanks and nukes (the horror if either "side" ever used one in anger). Diplomacy through cultural exchange is the best option we've got to prevent a cold war style escalation - and luckily the openness of both our cultures is the end goal we want to achieve anyway, right?

(apologies to all for the walls of text!)

jwm | 15 years ago | on: Congress Bans Some Scientific Collaboration with China, Citing Espionage Risk

I used to work with someone from China and, like you say above, she viewed the government as the same kind of benevolent infrastructure provider as I do mine. I think its overambitious to expect someone to completely turn their back on their view of their country in a few months after they have spent 20+ years of their lives in what they see to be a functioning society. It took two hundred plus years after the Enlightenment for all of our oh so Great Countries to finally rid themselves of kings and colonial rule.

As cabalamat says, I don't think there is anything more you can do to teach someone from China about Western values than having them completely immersed in our civilization. Some of our values must be crossing the waters, mustn't they? - if they really are self evidently superior?

I think collaboration is the best we can do - with the scientists and business men themselves, the people that actually matter, who's opinions people over there respect, not through the government. This kind of ban on collaboration hurts that.

There is nothing secret in science anyway. The US governments secrets on the other hand... - I would cynically agree there is always concern there. Both by US people themselves and the Chinese government:)

jwm | 15 years ago | on: Probabilistic processors possibly pack potent punch

> it would be fascinating if someone came up with the analog equivalent to a CLB in an FPGA and an HDL for describing non-linear computation

What you have described do indeed exist as Field Programmable Analog Arrays (FPAAs).

The Wikipedia article (http://en.wikipedia.org/wiki/FPAA) gives a good overview of them, but basically they consist of multiple configurable analog blocks (CABs), which can be configured to perform some analog operation on a signal, and multiple CABs can be connected together to form a signal path. All the signal paths and CAB parameters are defined by the digitally loaded configuration. Very interesting!

The one's I have briefly used (many years ago) were the Anadigm FPAAs. Examples of the operations the CABs (or "CAMs") can do are signal filtering, rectification, addition, multiplication, comparison and integration/differentiation over time (http://www.anadigm.com/_doc/PR021100-0024.pdf). These devices to me are really targeted at analog signal processing applications (audio, instrumentation etc). If I was an EE (which I am not) I might be able to provide a decent evaluation of them, but they seemed like they would be pretty useful for this kind of thing.

My project using them was to get the FPAAs to perform some simple physics calculations, based on previous work by another student. One example was modelling the height of a moving projectile under gravity. I can't remember the specifics (sorry!) but input voltages were used to specify the equation parameters (mass, initial force), the CABs transformed these voltages according to the given motion equation and the output voltage was the height at time t. And it worked ok! A computer used Digital-to-Analog converters to hold the input voltages steady for the FPAA circuits, and sampled the output using Analog-to-Digital converters.

While this worked for simple examples, the whole system was limited to 8-bit effective values by the Signal-to-Noise resolution of the equation signal path. While for the FPAA device itself has a high signal-to-noise ratio that effectively gives a smallish 20 bit resolution (~= SNR 120db), the extra wiring and components in the rest of my circuit added enough noise to lower this down to 8bit (~= SNR 48db). (Will happily admit I am no great circuitsmith:). Also there were some caveats like hard limits to the parameters of the CABs (restricted internally by the physical limits of the variable capacitors and resistors), which limit quantities used in the analog equations and restricts its general purposefulness.

Some of the things analog computers can do are interesting, like "instant" multiplication and division. However the difficulty of keeping thermally and electromagnetically induced noise low to get a high resolution signal (e.g. pushing past SNR 120db) in analog systems is one of the reasons why we don't really see them being used in computation any more. This is also one of the reasons why digital circuits are much much easier to work with as you no longer (really) have to worry about noise affecting accuracy, from the transistor level up to the PCB or long cable level.

This kind of thing explains the low 8-bit resolution from the device in the article.

> The technology allows a resolution of about 8 bits; that is, they can discriminate between about 2^8 = 256 different values (different probabilities) between 0 and VDD

High resolution analog seems to be just hard to do in practice.

(Aside: Also if you take with the width of the known universe, and discretize this distance by Planck length intervals, you only need ~220 bits to represent the position of an object on this line. So only ~3*220 bits for (x,y,z). Binary rules!)

So, I'm more of an digital fan for general purpose computing myself:) However analog computers are hella cool all the same.

EDIT: This post is long. You'll have to excuse the fact that I was finally happy for some information from the old undergrad thesis to see the light of day. TLDR: Analog computers are cool, but it seems they are limited in resolution and general configurability. Use FPGAs or GPUs or even poor old CPUs instead.

EDIT2: Rereading your post, maybe you were thinking about some kind of FPGA+FPAA hybrid? An FPGA, but with some with analog blocks and ADCs, DACs inside?

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