Omar Abo-Namous

Here is a nice article describing the problems that rise due to the methods used in nowadays computers to calculate simple mathematics. Interesting read.

With the use of mechatronically controllable flexible material, the shape-shifting robot created by iRobot can actively roll around in order to get from one place to another. Interesting and long-overdue transition mode.

More about it.

Zoom into Human Skin
von Weird_Weird_Science

Nice visualization of the use of multiscale measurement systems. Used sensors include a simple video camera, an opto-microscopic camera (maybe a confocal microscope) and i think they had to use an electronic microscope for the last steps. I like how they were able to smooth out the zoom operation accross the different scales.

More zoom-videos:

• Zoom into Hair
• Zoom into a tooth

A poem written in honor of the ever-enlightening Fourier-transform, which is often hated by students, mainly because they don’t know what it means.. Here is to the Fourier-transform:

One day in a land far away
Some mathematicians at play
Found a transform of convenient form
The basis of physics today.

Convolving would wreck people’s brains
Still the advent of Fourier domains
for convolving in one
means multiplication
in the corresponding domain.

Got trouble with an ODE?
Fourier transforms will set you free
When once you would cry,
You now multiply,
by a constant times the frequency.

Fourier transforms backwards and forth
I hope that you now see their worth
For in every domain
Advantages reign
Fourier was the salt of the earth.

by Luke Krieg
Posted to sci.physics, 11 Sep 2000

Thanks to Amara Graps (i was reading on wavelets..).

I needed to implement gray-code sequences for a fringe projection system i'm trying to build. To avoid hard to understand and not really intuitive C-code, i used gimp to produce the projection images. In this article i'm going to document the code used.

First is the script-fu function to generate a picture with a given number of fringes or - alternatively - a given width of the period:

Then there is the register-function call to enable the menu item for the function:

An older in-depth script-fu article by me.

Wolfram Alpha is finally the computer we were waiting for. Not only does it compute mathematical problems really fast, but it tries to give us everything about the answer, that we would like to find out. It's like a wikipedia - just with more accurate information. Also, WolframAlpha is able to interpret user input and find out what the user is trying to find out by searching for the terms of a query in a semantic database: Weather in Guatemala, President in Germany or C6H6O.

Below the answer set that WolframAlpha delivers, there is the option for an output as pdf-file and a rather general information of where the information came from.

I just found this nice educational ressource for numeric methods (i was specifically looking into LU decomposition).

Gray-Code is a binary code developed by Frank Gray in 1947. It is used by most absolute incremental encoders and some favor it's use for fringe projection systems that have to encode the pixel data in a series of image patterns (mostly fringes with differing widths). To convert Gray-Code from and to Decimal numbers using c++ i had to look up different approaches with varying difficulty levels. I then compiled the following algorithms, that i will be using for my own fringe projection system (keep tuned).

It's rather easy if you know how to do it. I had to find out the hard way, so here's for the rest of the world:

First the easy part: transforming a integer number dec into a Gray-code _code:

Now to the part of converting Gray-Code to binary and then decimal number: Suppose our Gray-code is inside the bitset _code.

bs holds the binary representation of the Gray-Code and _number is the decimal respresentation.

References:

• Gray code algorithms in Ruby by Wayne Conrad
• Gray-Code implementation in Java

This is a nice application of a handheld augmented reality simulator. Have a look:

The researcher has a website of his own with some interesting papers..

Wissenschaftler an der MIT haben herausgefunden, wie Insekten in der Lage sind, unterwasser zu atmen: Sie halten eine Luftblase am Unterleib. Dies wird vor allem durch gut platzierte Härchen ermöglicht, die die Auflösung oder Abkapselung des Bläschens verhindern.

MIT via BoingBoing