Friday, February 25, 2005

Bug-free design

Is it worth it actually plan what the design is going to be like before you start on it? Someone thinks so. And of course, you need a shared vision to do this team-wide.

Thursday, February 24, 2005

Need (open) photos?

If you need photos, it would be worth it to check out

Thursday, February 17, 2005

Will the copy "protectors" ever learn?

"We're not going to advise you to do anything untoward, but apparently if you install Winamp along with the Output Stacker plug-in you can convert those protected WMA files to WAV files and then burn them to CD without paying a penny. Or at least an extra penny," said in an item on its site.

A spokeswoman for Napster said that such endeavours were nothing new and the company was not too concerned.

"The DRM (digital rights management) is intact. Basically, people are just recording off a sound card. This is nothing new and people could do this with any legitimate service if they want to use a sound card," she said.

Monday, February 14, 2005

What's your Strouhal Number?

I was hoping to do some moderately original research in this area (completely outside my current fields of expertise), but I have not been able to find any data with which to do the research. Specificly, I need high quality digital video (preferrably with time markers) of multiple world-class runners covering a known distance. I also need to know the the length of their strides while doing that running.

Why? I think it would be worth it to compute a Strouhal number for an efficient (world-class) human. Don't some people seem to look like they are moving efficiently, while others seem to move rather inefficiently? Perhaps this could explain why. It also might help the world of robotics. Hmm... as I type this, I'm wondering if I can't do a fair amount of the research on myself.

What is a Strouhal number? This page does a good job of describing it:
For an animal or insect in flight, the Strouhal number is determined by the frequency (f ) of wing strokes, multiplied by the amplitude (A) of the wing, divided by the animal’s forward speed (U) through the air. The Strouhal number is equal to f A/U.
Note that the amplitude (A), also known as wingtip excursion, of the stroke is the vertical distance traveled by the tip of the wing during the flapping stroke (from highest point to lowest point). For a human, this would be the horizontal distance of the stride.

Nature magazine did an article on this topic and included a graph which shows that flying and swimming animals all have Strouhal numbers that fall into a range of 0.2 to 0.4.  Additional analysis was done at Oxford.

Biomechanics may come into play here, in which case, papers like this one and this one would be of interest for topics on the human stride. So would this discussion of the scaling of walking speed.
Perhaps someone has done some research on this with regard to humans now.  By the way, did you know everyone converts from walking to running between 2 and 3 m/s?

Speaking of efficiency (warning: drastic change of subject ahead)... here is a man after my own heart. Some might suggest that I need better organization skills... maybe I do, maybe I don't. Either way, this is an example of stuff to keep in mind.

Digital evolution, Genetic Algorithms, and syntheic design

Years ago, sometime in 2002 or 2003 I believe, I found an interesting article (in Wired or some other technical/scientific magazine) about how a group had taken an analog circuit and had given it to a genetic algorithm type program to iterate on it. The program's job was to see if it could produce a better circuit - one with more bandwidth and fewer parts - by doing various (mostly random, if I recall) things. The output of the altered circuit would be checked to make sure it performed the same functions as the original, then the altered circuit would be put back into the program. Alter -> test -> repeat.

The result? The circuit evolved into something that was smaller, and worked better. And engineers don't understand the new circuit. This tells me we are still a ways, perhaps a long ways, from truly understanding electronics.

I wish I could find that original article. The closest thing I've come up with is a site about "Evolving Self-Diagnosing Hardware," done by someone at Sussex.

Tim Gorden has also done some interesting work in this area, and /. just had an article about a digital virus which played dead to avoid "being killed". There is even an Evolvable Hardware conference.

Unfortunately, many of these links are going to go away someday since the people are at college. It would be worth it to save all their papers off line for future reference.

A big thanks to Bigdakine, here is the article I was referring to above:
In February's Scientific American (2003), there is an article written by engineers and computer scientists who used GA's to create novel electronic circuit deisgns. They were able to duplicate or better 15 previously patented designs using GA's.

In the case of the most complicated task, designing a "cubic signal generator", the GA evolved a design which out performs a recently patented design that performs the same task. GA's don't think. They have no cognitive ability. Yet this GA *designed* such a good circuit. Its even more interesting than that. TO quote the authors, "The evolved circuit performs with better accuracy than the designed one, but how it functions is not understood. The evolved circuit is clearly more complicated, but also contains redundant parts, such as the purple transistor that contributes nothing to the functioning." (Page 58, Feb 2003 issue of Sci-Am)
There is another pointer to it, along with a different article worth reading, at C# Corner.

Update2: Radio emerges from electronic soup, Analysis of Unconventional Evolved Electronics, /. link. Oh, and wikipedia.

Update3: Synthetic design may be able to solve other problems too... like how to design a better bridge. But can we determine how much better (via how much additional cost or material it adds or consumes)?

Tuesday, February 08, 2005

Diamonds for everyone?

Taken from here, some interesting stats on Apollo's Diamonds:

All of the samples fluoresced a very weak yellow-orange to long-wave UV radiation, and a weak to moderate yellow-orange to short-wave UV. As a characteristic feature, the CVD synthetic diamonds displayed strong red fluorescence while exposed to high-energy UV radiation in the De Beers DiamondView.

Infrared absorption spectra showed that the CVD laboratory-created diamonds were type IIa, and some contained trace amounts of isolated nitrogen. Photoluminescence spectra suggested the presence of N-V centers, indicated by very strong emission peaks at 575 nm and 637 nm. Also observed were features such as H-related absorption at 3123 cm-1 in the mid-infrared range and a relatively strong photoluminescence emission at 737 nm due to trace impurities of silicon.
I wonder if there will ever come a day that it will not be worth it to differentiate between natural and man-grown diamonds. Probably not as long as DeBeers is around.


/. As a follow-up to the over-all guessing on cell architecture mentioned last month, a few more details have been released that are worth it to read. See arstechnica's write up, for example.

then we have researchers at Lawrence Berkeley National Laboratory running comparisons on it.