Science, common sense, and the determination of mental capacity.

In 1993, when the Supreme Court decided Daubert and created the modern standard for the admissibility of scientific evidence, it almost certainly did not consider its possible effect on evidentiary hearings in probate courts even though such courts routinely admit expert testimony in will contests and guardianship hearings. Probate courts also admit testimony of lay witnesses who express their opinion as to the mental capacity of the individual in question. Yet both expert and lay witnesses are only "fact bringers" and not "fact interpreters" because the ultimate question of capacity is legal, not factual. Because the determination of legal capacity is made by the judge or jury, the role of experts in capacity trials is not fundamentally different than that of lay persons. The limited role of the expert suggests that probate courts should allow great latitude in the admission of expert testimony because the fact finders must ultimately rely on their own amorphous sense of "legal capacity." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An asymmetric discrete-time approach for the design and analysis ofperiodic waveguide gratings

A discrete-time approach is introduced for the analysis of periodic waveguide gratings with gain (or loss) extending concepts developed for transfer matrix and Gel'fand-Levitan-Marchenko (GLM) inverse scattering techniques. The periodic waveguide grating with gain (or loss) is modeled as a lossy layered dielectric that allows for a digital signal processing (DSP) formulation of the forward and inverse scattering problem. It is shown that the DSP forward scattering formulation as an asymmetric two-component wave system is equivalent to the impedance matching matrix method. A numerical example is presented to emphasize this result. The DSP formulation is an exact discrete design, not just an approximation to a continuous design, and includes all multiple reflections, transmission scattering losses, and absorption effects. A comparison of the continuous GLM, discrete GLM, and discrete Krein inverse problem formulations for a medium with gain (or loss) is presented. The discrete lossy formulations generalize previous lossless results and are found from two different types of reflection data. Since slab gratings are discrete (not continuous) structures, the integral equations used to describe the continuous inverse problem are shown to become matrix equations. Thus, our result enables fast algorithms to be used to solve the inverse problem. A fast algorithm is presented allowing for the complete reconstruction of the grating parameters from its two-sided response in a recursive (slab by slab) fashion     

Wireless sensor systems: an approach for a multiuniversity designcourse

As a means of increasing the awareness of the sensing sciences among undergraduates, a novel design course has been developed by the Tennessee Technological University and the University of South Florida. Students study, design, fabricate, and test a wireless-based sensor system that relays data over a radio-frequency link for centralized processing. Weekly seminars on applicable topics in telecommunication, signal processing, and microwave systems originate from either university, using interactive Internet conferencing. Students from both schools form design teams to develop subsystems that are integrated to complete the project, thereby necessitating collaboration across teams and universities. Student evaluations of the first two offerings (Spring 2000/2001) were excellent     

A low-cost wireless platform for first-year interdisciplinary projects

This paper presents a low-cost wireless circuit that is demonstrated to be a simple, yet flexible platform to support a variety of low-level educational activities. The circuit, implemented by many for K-12 outreach activities, is based on a 555-timer and an AM radio transmitter. At the University of Vermont, Burlington, this CricketSat circuit has enabled the development of a wide variety of wireless sensor and actuator projects. In this paper, design specifics, circuit utilization within an interdisciplinary first-year design course, and assessment results are presented. The novelty of the approach is twofold. First, the course and projects pertain to the area of wireless sensor networks. Second, student groups come up with their own project applications and problem statements for which to design a system. The key finding is that this platform has enabled students to take ownership of a concept and bring it to a working reality within the time constraints of a single semester course.     

On the feasibility of impulse reflection response data from one-dimensional multilayered lossy media

Solving inverse scattering problems using layer stripping algorithms is known to be fast and effective when the data are noise-free. However, layer stripping algorithms have a reputation of being unstable when applied to noisy time-domain reflection response data. The reason is that the noisy data may be infeasible; i.e., could not have been produced by an actual media. In this paper, three feasibility conditions are introduced for data from absorbing (lossy) one-dimensional (1-D) media. Satisfying these conditions is both necessary and sufficient for the data to have been produced by an actual lossy media. That is, layer stripping algorithms applied such noisy but feasible data are stable. A methodology for correcting infeasible data is also proposed. Numerical examples illustrate key points and the correction method.     

Implementation of Handheld, RF Test Equipment in the Classroom and the Field

The utilization of handheld, radio frequency (RF) equipment (spectrum analyzers and signal generators) for both classroom demonstrations and for student exercises conducted in the field is discussed. Demonstrations employ real-world, wireless systems to illustrate undergraduate concepts, such as channel access, modulation methods, and transmission bandwidth. The equipment has also been used to illustrate antenna concepts, such as gain, beamwidth, and polarization. Finally, the portability and robustness of the equipment has enabled students to collect field data for the purpose of characterizing both large- and small-scale propagation effects in a variety of environments.     

On the feasibility of impulse reflection response data for thetwo-dimensional inverse scattering problem

Layer stripping algorithms for inverse scattering problems are very fast but have the reputation of being numerically unstable, especially when applied to noisy data. The goal of this paper is to provide an explicitly discrete framework for layer stripping algorithms for the two-dimensional (2-D) Schrodinger equation inverse scattering problem. We determine when 2-D layer stripping algorithms are numerically stable, explain why they are stable, and specify exactly the (discrete) problem they solve when they are stable. We reformulate the 2-D Schrodinger equation as a multichannel two-component wave system by Fourier transforming the Schrodinger equation in the lateral spatial variable. Discretization results in new 2-D layer stripping algorithms which incorporate multichannel transmission effects; this leads to an important new feasibility condition on impulse reflection response data for stability of these algorithms. A 2-D discrete Schrodinger equation is defined, and analogous results are obtained. Numerical examples illustrate the new results, especially how rendering noisy data feasible stabilizes layer stripping algorithms     

Quantifying streambank movement and topography using unmanned aircraft system photogrammetry with comparison to terrestrial laser scanning

Streambank movement is an integral part of geomorphic changes along river corridors and affects a range of physical, ecological, and socio‐economic systems including aquatic habitat, water quality, and infrastructure. Various methods have been used to quantify streambank erosion, including bank pins, ground surveys, lidar, and analytical models, however, due to high‐cost or labour intensive fieldwork these are typically feasible or appropriate only for site‐specific studies. Advancements in unmanned aircraft systems (UAS) and photogrammetry provide opportunities for more rapid and economical quantification of streambank erosion and deposition at variable scales. This work assesses the performance of UAS‐based photogrammetry for capturing topography of streambank surfaces and quantifying bank movement. UAS data are compared to terrestrial laser scanner (TLS) and GPS surveying from streambank sites located in Vermont that featured a variety of bank conditions and vegetation. Cross‐sectional analysis of data from UAS and TLS revealed that the UAS reliably captured the bank surface within 0.2 m of TLS and GPS surveys across all sites during leaf‐off conditions. Mean error between UAS and TLS was only 0.11 m in early spring conditions. Dense summer vegetation resulted in decreased accuracy and was a limiting factor in the ability of the UAS to capture the ground surface. At areas with observed bank movement, the change in cross‐sectional area estimated using UAS data compared reliably to TLS survey for net cross‐sectional changes greater than 3.5 m², given a 10% error tolerance. At locations with smaller changes, error increased due to the effect of vegetation, georeferencing, and overhanging bank profiles. UAS‐based photogrammetry shows significant promise for capturing bank topography and movement at fine resolutions in a flexible and efficient manner.     

Cationic latex: Colloidal behavior and interaction with anionic pulp fibers

Styrene–butadiene latexes were prepared in the absence of an emulsifier using a redox initiator Fe(NO₃)₃/H₂O₂. Their positive charge was supplied by comonomer N,N‐diethyl aminoethyl methacrylate. At a given styrene–butadiene ratio (60/40) the particle size depends on the concentration of the comonomer and initiator. The latexes are stabilized by electrostatic repulsion, and remain positively charged and stable up to pH 8. At a higher pH, they acquire a negative charge and restabilize. The positively charged particles deposit readily on negatively charged fibers dispersed in water, thus covering the fiber surface. Upon dewatering and drying, the particles coalesce, and the fibers become covered by a polymeric film, which improves the interfiber bonding and, consequently, the mechanical properties of the fiber assembly. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1677–1682, 2000