Comparison of GLR and invariant detectors under structured cluttercovariance

This paper addresses a target detection problem in radar imaging for which the covariance matrix of unknown Gaussian clutter has block diagonal structure. This block diagonal structure is the consequence of a target lying along a boundary between two statistically independent clutter regions. Here, we design adaptive detection algorithms using both the generalized likelihood ratio (GLR) and the invariance principles. There has been considerable interest in applying invariant hypothesis testing as an alternative to the GLR test. This interest has been motivated by several attractive properties of invariant tests including: exact robustness to variation of nuisance parameters and possible finite-sample min-max optimality. However, in our deep-hide target detection problem, there are regimes for which neither the GLR nor the invariant tests uniformly outperforms the other. We discuss the relative advantages of GLR and invariance procedures in the context of this radar imaging and target detection application.     

The intravenous route to blood glucose control

This article discusses closed-loop blood glucose regulation algorithms that use the intravenous route for insulin delivery to insulin-dependent diabetic patients. Classical control methods and advanced algorithms using implicit knowledge or explicit models (empirical, fundamental, or “gray-box”) of the diabetic patient are examined. Current research on characterizing patient variability is presented, in the context of a model predictive controller able to adjust to changes in patient glucose and insulin sensitivity     

ANALYSIS AND DESIGN OF MULTIPORT WAVEGUIDE JUNCTIONS WITH ARTIFICIAL INCLUSIONS FORMED OF CONDUCTING STRIPS

A rigorous electromagnetic theory is developed to analyze multiport waveguide junctions with artificial inclusions formed of the conducting strips and dielectric layers. The method is based on the Fourier transform technique combined with the mode matching method technique that takes into account the edge conditions in vicinity of the strip edges. The scattering characteristics of a 3-port junction are discussed with the numerical examples for the SWR maps, the power reflection and transmission coefficients, and the 2D plots of near fields distributions inside the junction area. A strategy of optimize matching properties of the 3-port waveguide junctions is also presented.     

Are SSATS and GPA enough? A theory-based approach to predicting academic success in secondary school.

Two studies were carried out to predict academic success in the highly competitive environment of a private preparatory school, Choate Rosemary Hall. The 1st study focused on the question of whether there are indicators beyond middle school grade-point average (GPA) and standardized test scores that might enhance the validity of measures for predicting success of students attending Choate. The results indicated the importance of taking into account aspects of self-regulated learning (SRL), such as academic self-efficacy, academic motivation, academic locus of control, and measures of the WICS (Wisdom, Intelligence, Creativity Synthesized) theoretical framework. Both sets of SRL and WICS indicators demonstrated incremental validity in predicting success at Choate. The 2nd study preliminarily evaluated the value of including indicators of aspects of the SRL and the WICS theoretical framework into the Choate admission process. The results of this study examined the utility of using quantified indicators other than middle-school GPA and standardized test scores for making admission decisions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Measurement of the force required to move a neurosurgical probethrough in vivo human brain tissue

The advent of high-precision magnetic and robotic computer-controlled neurosurgery systems makes it necessary to determine the range of forces that will be encountered by the probes of such devices as they are guided through the brain tissues to intraparenchymal targets. We have measured the penetration forces on 2.5-mm spheres and the drag forces on 3.0-mm ventricular shunt catheters advanced 2.0-3.5 cm deep into in vivo human brain tissues (in patients about to have those tissues resected during epilepsy surgery) at rates of approximately 0.33 mm s-1. Penetration forces of (8 +/- 2) grams were found for the spherical probe once it passed 0.5 cm below the cortical surface, and frictional drags of (2.8 +/- 0.3) grams cm-1 were exerted on the catheters. The variable nature of these forces is discussed and the results are compared with earlier studies on experimental animal tissues and brain phantom gelatins. The implications of these results for magnetic and robotic surgery systems are considered.     

Reduced-order methodologies for feedback control of particle size distribution in semi-batch emulsion copolymerization

Within-batch feedback control strategies are developed for the regulation of the particle size distribution (PSD) in a semibatch vinyl acetate (VAc)/butyl acrylate (BuA) emulsion copolymerization system. These strategies are also applicable for regulation of distributions in other particulate systems governed by population balances. In the first strategy, PID controllers are employed for regulating nucleation and growth events through tracking the nominal trajectories of total number of particles and the solids content by manipulating the feed-rates of the more reactive monomer, BuA, and the surfactant. The second control strategy is based on tracking nominal trajectories of the moments of the distribution with a quadratic dynamic matrix controller (QDMC). To determine the appropriate number of moments to describe the PSD during various stages of a nominal batch, a maximum-entropy approach is utilized. In the final and most complex approach, a nonlinear model predictive controller is designed utilizing the detailed population balance model of the system. The ill-conditioning resulting from the high-dimensionality of the resulting dynamical system is removed by principal component analysis (PCA)-based model order reduction and a multi-rate estimator is designed to compensate for the measurement delay associated with the PSD measurements.     

Nonparametric belief propagation for self-localization of sensor networks

Automatic self-localization is a critical need for the effective use of ad hoc sensor networks in military or civilian applications. In general, self-localization involves the combination of absolute location information (e.g., from a global positioning system) with relative calibration information (e.g., distance measurements between sensors) over regions of the network. Furthermore, it is generally desirable to distribute the computational burden across the network and minimize the amount of intersensor communication. We demonstrate that the information used for sensor localization is fundamentally local with regard to the network topology and use this observation to reformulate the problem within a graphical model framework. We then present and demonstrate the utility of nonparametric belief propagation (NBP), a recent generalization of particle filtering, for both estimating sensor locations and representing location uncertainties. NBP has the advantage that it is easily implemented in a distributed fashion, admits a wide variety of statistical models, and can represent multimodal uncertainty. Using simulations of small to moderately sized sensor networks, we show that NBP may be made robust to outlier measurement errors by a simple model augmentation, and that judicious message construction can result in better estimates. Furthermore, we provide an analysis of NBP's communications requirements, showing that typically only a few messages per sensor are required, and that even low bit-rate approximations of these messages can be used with little or no performance impact.     

Adviser: immersive field work for planetary geoscientists

The Adviser prototype system makes it possible for planetary geologists to conduct virtual field research on remote environments such as Antarctica and Mars. Among Adviser's interactive tools are mission-planning and measurement tools that let researchers generate new data and gain interpretive insights. Five case studies illustrate the system's applications and observed benefits.