Publications

A linearly-polarized ultrawideband dipole array antenna has been developed for coverage in the VHF/UHF frequency range for communications or radar applications. The antenna design utilizes a horizontally polarized array of thick tubular dipole elements above a ground plane. Numerical electromagnetic simulations were used to analyze and optimize the antenna parameters...

The measured results from an X-band electronically scanned array using an overlapped subarray architecture are presented. The 2D architecture uses a 12 x 12 element subarray with 3 to 1 overlapping. The active electronic scanned array is a receive only implementation consisting of switch, low noise amplifier, phase shifter and...

We have demonstrated a new 3D device interconnect approach, with direct back side via connection to a transistor in a 3D stack, resulting in a reduced 3D footprint by an estimated ~40% as well as potential for lower series resistance. We have demonstrated high yield 3D through-oxide-via (TOV) with a...

A highly scalable approach for producing surface-enhanced Raman spectroscopy substrates is introduced. The novel method involves assembling individual nanoparticles in pre-defined templates, one particle per template, forming a high denisity of nanogaps over large areas, while decoupling nanostructure synthesis from placement.

Collision avoidance systems, whether for manned or unmanned aircraft, must reliably prevent collision while minimizing alerts. Deciding what action to execute at a particular instant may be framed as a multiple-objective optimization problem that can be solved offline by computers. Prior work has explored methods of efficiently computing the optimal...

Modeling aircraft taxi operations is an important element in understanding current airport performance and where opportunities may lie for improvements. A statistical learning approach to modeling aircraft taxi time is presented in this paper. This approach allows efficient identification of relatively simple and easily interpretable models of aircraft taxi time...

We present a framework for optimizing the distributed performance of sparse matrix computations. These computations are optimally parallelized by distributing their operations across processors in a subtly uneven balance. Because the optimal balance point depends on the non-zero patterns in the data, the algorithm, and the underlying hardware architecture, it...

Popular methods for speaker classification perform speaker comparison in a high-dimensional space, however, recent work has shown that most of the speaker variability is captured by a low-dimensional subspace of that space. In this paper we examine whether additional structure in terms of nonlinear manifolds exist within the high-dimensional space...

A method coupling field evaluation with operations data analysis is presented as an effective means to functionally evolve a decision support system. The case study used to illustrate this method is the evaluation of the Route Availability Planning Tool (RAPT), a decision support tool to improve departure efficiency in convective...

We describe a simple, novel, and efficient system for speaker comparison with two main components. First, the system uses a new approximate KL divergence distance extending earlier GMM parameter vector SVM kernels. The approximate distance incorporates data-dependent mixture weights as well as the standard MAP-adapted GMM mean parameters. Second, the...