Publications

We present a comparison of three cluster-finding algorithms from imaging data using Monte Carlo simulations of clusters embedded in a 25 deg(2) region of Sloan Digital Sky Survey (SDSS) imaging data: the matched filter (MF), the adaptive matched filter (AMF), and a color-magnitude filtered Voronoi tessellation technique (VTT). Among the...

Decision-directed learning (DDL) is an iterative discrete approach to finding a feasible solution for large-scale combinatorial optimization problems. DDL is capable of efficiently formulating a solution to network scheduling problems that involve load limiting device utilization, selecting parallel configurations for software applications and host hardware using a minimum set of...

Multimedia education has quickly entered our classrooms and offices providing tutorials and lessons on many different topics. The assumption that most people interact with these multimedia systems in similar ways can easily be made, but are these assumptions valid? What factors determine whether students will embrace computer-based multimedia-augmented learning? One...

Real-time signal processing consumes the majority of the world's computing power Increasingly, programmable parallel microprocessors are used to address a wide variety of signal processing applications (e.g. scientific, video, wireless, medical, communication, encoding, radar, sonar and imaging). In programmable systems the major challenge is no longer hardware but software. Specifically...

In this paper, a circuit-fed spatially combined transmitter array is described for operation at 44 GHz. The array contains 256 elements where each element consists of a monolithic-microwave integrated-circuit amplifier and a circularly polarized microchip patch antenna. The array is constructed using 16-element tile-approach subarrays. Each subarray is a two...

Determining causes of aviation delay is essential for formulating and evaluating approaches to reduce air traffic delays. An analysis was conducted of large weather-related delays at Newark International Airport (EWR), which, located in the heart of the congested northeast corridor of the United States, is an airport with a significant...

Delay increases during the months of the year characterized by thunderstorms have been the principal cause of the dramatic delay growth in the US aviation system over the past 3 years, as shown in Figure 1. In 2000, the key new initiative for reducing these convective weather delays was "strategic"...

We investigate the effect of speech coding on automatic speaker recognition when training and testing conditions are matched and mismatched. Experiments used standard speech coding algorithms (GSM, G.729, G.723, MELP) and a speaker recognition system based on Gaussian mixture models adapted from a universal background model. There is little loss...

Optically sampled analog-to-digital converters (ADCs) combine optical sampling with electronic quantization to enhance the performance of electronic ADCs. In this paper, we review the prior and current work in this field, and then describe our efforts to develop and extend the bandwidth of a linearized sampling technique referred to as...

This report documents the analysis of and subsequent improvements to the performance of the ASR-8/TDX-2000 digitizer equipment combination. Working at the FAA's Palm Springs, CA and Williams (Mesa, AZ) ASR-8 facilities, data was methodically collected and analyzed to isolate the causes of reported correlated radar-only tracks that were being dropped...