brainwagon

Ever wonder why our clocks divide hours into sixty minutes of sixty seconds? What’s up with the sixty? I mean, factors of five and ten make some sense, but why sixty? Well, as it turns out, these things have some nifty properties because sixty has so many small factors. 60 = 2 * 3 * […]

We’d all like to get better gas mileage from our cars. Well, me especially. My Ford Expedition isn’t exactly the cheapest car to put on the road. But so-called “hypermilers” take this to the extreme by adopting a number of techniques to reduce fuel consumption: such as drafting trucks with the engine off, or taking […]

I know a couple of readers of mine are interested in woodworking, so when I saw Handiwork in Wood come by on the recently completed list over at Distributed Proofreaders, I thought I’d have a look. The title suggested a book about the working of wood with handtools, and indeed, the book does that, but […]

I’ve done this before, it’s kind of a fun little project to do. “Under your desk, you’ll find a computer and a C compiler. Write a program to create some interesting images.” PixelMachine

I was pondering the universe of flight simulation last night. Found some online references which I’ll archive here for fun: Npsnet: Flight Simulation Dynamic Modeling Using Quaternions A Standard Kinematic Model For Flight Simulation at NASA-AMES Euler Angles, Quaternions, and Teransformation Matrices [tags]Mathematic,Flight Simulation[/tags]

Tom does probably as much if not as more code tinkering as I do, and his is probably more interesting. At lunch today he mentioned that he implemented Knuth’s Algorithm X for solving the exact cover problem. I couldn’t remember what that was, but I did recall it was related to Knuth’s Dancing Links, which […]

Need an introductory guide to the stars? You could worse than downloading William Tyler Olcott’s A Field Book of the Stars. It’s not the most detailed, but will get you started in being able to navigate the skies with your naked eyes, a pair of binoculars or even a small telescope. Good stuff, and the […]

While I was up in Truckee this weekend with some of my old college buddies, David said that his daughter had received an assignment which was to pick someone whose birthday we should make into a national holiday. Their rather excellent suggestion was that Albert Einstein would make an excellent choice. As it happens, Albert […]

Carmen and I got back from a trip to Truckee/Reno.  She wanted to take skiing lessons, so we did.  We both did well and had fun.  She also took me to the driving range and taught me how to smack balls into the water.  That was fun too. [tags]Vacation[/tags]

While working on my various and sundry Ï€ programs, I kept finding references to Gosper’s paper Acceleration of Series, so I thought I’d find it on the web and have a read. It’s quite the magnum opus of series acceleration with all sorts of gems that are, to be truthful, beyond my understanding. Worth reading, […]

You just can’t make crap like this up.

As part of Cornell Uniersity’s Making of America, they have scans of Scientific American from 1846-1869. Very nice, albeit with their rather obtuse and probably meaningless usage restrictions. [tags]Public Domain,Scientific American[/tags] Here’s the full page of an issue which describes Lord Rosse’s telescope (with the illustration below). Oops. That was a link to the gifcache. […]

Well, after tinkering around with my implementation of the BBP algorithm a bit more, i was able to get it to work out until about 108, but no further. I suspect that some kind of implicit type conversion was happening that was truncating values in an inappropriate way, resulting in loss of precision. So, after […]

Textbooks are expensive, but useful. Check out this collection of links to online mathematics textbooks. I found this link in a posting on the Random Hacks weblog. It includes a link to Jim Hefferson’s Linear Algebra, which is a subject that I’m trying to revisit after forgetting everything I knew about it in college. Enjoy. […]

Courtesy of the Unapologetic Mathematician, here’s a link to a History of Knot Theory from Jozel Przytycki’s book on the subject. I’ve got a couple of books on knot theory (and more than a few on just tying interesting knots), so I’ll have to check this out. [tags]Mathematics,Knot Theory[/tags]