Benchmarking hypercube hardware and software

It was long a truism in computer systems design that balanced systems achieve the best performance. Message passing parallel processors are no different. To quantify the balance of a hypercube design, an experimental methodology was developed and the associated suite of benchmarks was applied to several existing hypercubes. The benchmark suite includes tests of both processor speed in the absence of internode communication and message transmission speed as a function of communication patterns

Design of a Programmable Star Tracker-Based Reference System For a Simulated Spacecraft

The main objective of this research effort is to achieve an accuracy level for the SimSat star tracker system comparable to what is reported in current literature by various star tracker manufacturers and researchers. Previous work has provided a spherical star dome that needs to be fully populated with light sources. Programmable organic light emitting diode (OLED) panels were chosen to populate the dome to allow high contrast ratios without backlighting and increase the number of star combinations able to be represented. Noise equivalent angles less than five arcseconds (1 delta ) are achieved about the boresight axis and less than half an arcsecond around the other axes. Absolute accuracy near the center of the star dome is tested to be less than 0.04 degree about each axis. Two different approaches to inertially cataloging the star eld are also investigated, externally referencing each panels coordinates using a coordinate measurement arm and utilizing the camera\u27s known position to catalog the panel\u27s location. The full population of the SimSat star dome and reprogrammable capability of the panels allows many future research endeavors related to star pattern recognition and attitude determination to be undertaken

Nonlinear denoising of transient signals with application to event related potentials

We present a new wavelet based method for the denoising of {\it event related potentials} ERPs), employing techniques recently developed for the paradigm of deterministic chaotic systems. The denoising scheme has been constructed to be appropriate for short and transient time sequences using circular state space embedding. Its effectiveness was successfully tested on simulated signals as well as on ERPs recorded from within a human brain. The method enables the study of individual ERPs against strong ongoing brain electrical activity.Comment: 16 pages, Postscript, 6 figures, Physica D in pres