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OGR

· Secure wireless communication

· Precision 3-D mapping with X-Rays

·Large arrays of optical or radio telescopes

What do they all have in common? They all use OGRs to be efficient and accurate.

OGR stands for "Optimal Golomb Ruler," but that still bears a little more explaination for most of us. Let’s start with "Golomb." It's the name of mathematician Dr. Solomon Golomb. The word "optimal" means "best," and "rulers" are used to measure things. From this one can conclude that Dr. Golomb wanted the "best rulers" for his math project.

OGRs come in all lengths. Currently, the longest proven OGR is 23 marks in length. It took a lot of computing power to prove OGR-23. Distributed Net is close to proving a 24-mark ruler, and is hard at work on a 25-mark ruler. Here is the OGR-24 and OGR-25 completion chart.

Distributed.net has a very good set of pages explaining the "how and what" part of Optimal Golomb Rulers, so for an in-depth explaination of OGRs, take a look at http://www.distributed.net/ogr/. In practical terms, however, how does OGR impact the three examples above?

Modern wireless communication uses spread-spectrum communication. Rather than use just one wide-band radio frequency, they use multiple narrow-band frequencies and spread the data across each one. If you allocate 10 frequencies, but only need 5, then one can use a military trick called frequency-hopping to make one's communication secure, because the signal jumps around among the 10 frequencies in a pattern that unwanted listeners can’t follow. The more frequencies used, the more secure the transmission is. The problem is, not all frequencies work well together. Unless close attention is paid to the gaps between them, they will interfere with each other and reduce the distance and clarity of the signal. But, if frequencies are chosen using Optimal Golomb Rulers, interference can be eliminated. Longer Optimal Golomb Rulers mean better communication.

3-D X-ray mapping, otherwise known as X-Ray crystallography, also needs OGRs for accuracy and increased detail. If one crystallizes a sample of organic material, then places it in a chamber and targets it with X-Rays, one can detect the pattern those X-Rays make as they are diffracted by the crystal structure. The result is a 3D picture of the inside and outside of the object being scanned. The secret here is the placement of the X-Ray sensors around the chamber. If one places them properly (in an OGR-based pattern), they will not introduce their own interference patterns into the final 3D composite.

In the case of telescopes, both radio and optical, it's possible to build them bigger and bigger , but it becomes very expensive. The trend now is to build arrays of smaller telescopes and combine the results to get the equivalent of a huge telescope. A linear array of telescopes, perhaps measuring hundreds or thousands of kilometers in total distance, would be great. If one picks the distances between them carefully (in an OGR-based pattern), one gets the best output in the minimum distance. Because no two distances between telescopes are repeated when using an OGR-based pattern, it is easier to computer-enhance the output to get very accurate images from either optical or radio telescopes.

Sound interesting? Then, please help Team AnandTech as we work with Distributed.net in finding longer and better Optimal Golomb Rulers.

Click Here to find out how to Join Team AnandTech's OGR Team