Publications
Capacity bounds for frequency-hopped BPSK
Summary
Summary
In some channels, such as the frequency-hop channel, the transmission may undergo abrupt transitions in phase. This can require the receiver to re-estimate the phase on each hop, or for the system to utilize modulation techniques that lend themselves to noncoherent detection. How well the receiver can estimate the phase...
Application of complex split-activation feedforward networks to beamforming
Summary
Summary
In increasingly congested RF environments and for jamming at closer ranges, amplifiers may introduce nonlinearities that linear adaptive beamforming techniques can't mitigate. Machine learning architectures are intended to solve such nonlinear least squares problems, but much of the current work and available software is limited to signals represented as real...
Detecting pathogen exposure during the non-symptomatic incubation period using physiological data: proof of concept in non-human primates
Summary
Summary
Background and Objectives: Early warning of bacterial and viral infection, prior to the development of overt clinical symptoms, allows not only for improved patient care and outcomes but also enables faster implementation of public health measures (patient isolation and contact tracing). Our primary objectives in this effort are 3-fold. First...
Using oculomotor features to predict changes in optic nerve sheath diameter and ImPACT scores from contact-sport athletes
Summary
Summary
There is mounting evidence linking the cumulative effects of repetitive head impacts to neuro-degenerative conditions. Robust clinical assessment tools to identify mild traumatic brain injuries are needed to assist with timely diagnosis for return-to-field decisions and appropriately guide rehabilitation. The focus of the present study is to investigate the potential...
Detecting pathogen exposure during the non-symptomatic incubation period using physiological data
Summary
Summary
Early pathogen exposure detection allows better patient care and faster implementation of public health measures (patient isolation, contact tracing). Existing exposure detection most frequently relies on overt clinical symptoms, namely fever, during the infectious prodromal period. We have developed a robust machine learning based method to better detect asymptomatic states...
Detecting virus exposure during the pre-symptomatic incubation period using physiological data
Summary
Summary
Early pathogen exposure detection allows better patient care and faster implementation of public health measures (patient isolation, contact tracing). Existing exposure detection most frequently relies on overt clinical symptoms, namely fever, during the infectious prodromal period. We have developed a robust machine learning method to better detect asymptomatic states during...
Distributed multi-modal sensor system for searching a foliage-covered region
Summary
Summary
We designed and constructed a system that includes aircraft, ground vehicles, and throwable sensors to search a semiforested region that was partially covered by foliage. The system contained 4 radio-controlled (RC) trucks, 2 aircraft, and 30 SensorMotes (throwable sensors). We also investigated communications links, search strategies, and system architecture. Our...
Circuit-fed tile-approach configuration for millimeter-wave spatial power combining
Summary
Summary
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...
Comparison of two flat reflector-type designs for dual-polarization, dual-band operation
Summary
Summary
The parabolic reflector remains an essential antenna for high-gain applications. This is a result of its desirable characteristics based on geometric optics. These include relative frequency independence for sufficiently large apertures and high aperture efficiency. However, the parabolic reflector occupies a large volume. This may be aesthetically unappealing on the...
Accurate modeling of dual dipole and slot elements used with photomixers for coherent terahertz output power
Summary
Summary
Accurate circuit models derived from electromagnetic simulations have been used to fabricate photomixer sources with optimized high-impedance antennas. Output powers on the order of 1 uW were measured for various designs spanning 0.6-2.7 THz. The improvement in output power ranged from 3 to 10 dB over more conventionally designed photomixers...