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When materials are to be treated with microwaves for different purposes such as drying, online moisture measurements, disinfestation, and remote sensing, thorough knowledge of the material dielectric properties becomes extremely important. Unlike for other materials, measurement of vegetation dielectric properties is very complicated due to the nature of the materials themselves. Hence, vegetation dielectric models that require fewer accurately and easily measurable physical quantities are of great importance. Therefore, dielectric models that only require the measurement of moisture content (MC) have been investigated for alfalfa, a plant material that has high commercial value in national and international markets. The models were developed by measuring the dielectric properties by using an open-ended coaxial probe at frequencies ranging from over 300 MHz to 18 GHz at 22 [degrees]C and at an MC ranging from 12% to 73% in wet basis. Index Terms--Alfalfa, bound water, coaxial probe, microwave dielectric properties, moisture content (MC).

A noncontact velocity measurement system designed for a radiating or reflecting surface under motion is introduced and theoretically investigated. The measurement error bias and variance is formulated in terms of the spatial power spectrum of the light or sound energy, the sensor's noise power spectrum, the sensor alignment error and the filters's frequency response. The system consists of two stationary sensors atop a surface whose light intensity or radiated sound varies with position.

Design, development, and implementation of a computer-aided design (CAD) tool for developing digital controllers and relays is presented in this paper. The development includes modeling A/D converters, software, and the necessary logic. Procedures for modeling A/D converters and simulating the software are described. Application of the CAD tool is demonstrated by evaluating and comparing three different designs of a digital overcurrent relay. The designs are evaluated to determine both the speed and accuracy of the relays. The effects of the size of the A/D converters, the word-size used in computations, and the effects of truncation/rounding are included in the simulation. The paper also describes the algorithm used in the relay design.

Artificial neural networks (ANN'S) allow a new approach to biological modeling. The main applications of ANN'S have been geared towards the modeling of the association and learning mechanisms of the brain; only a few researchers have explored them for motor control. The fact that ANN'S are based on biological systems indicates their potential application for a biological act such as locomotion. Towards this goal, we have developed a 'movement pattern generator,' using an ANN for generating periodic movement trajectories. This model is based on the concept of 'central pattern generators.' Jordan's sequential network, which is capable of learning sequences of patterns, was modified and used to generate several bipedal trajectories (or gaits), coded in task space, at different frequencies. The network model successfully learned all of the trajectories presented to it. The model has many attractive properties such as limit cycle behavior, generalization of trajectories and frequencies, phase maintenance, and fault tolerance. The movement pattern generator model is potentially applicable for improved understanding of animal locomotion and for use in legged robots and rehabilitation medicine.

Dielectric properties (i.e., permittivity) are essential in designing, simulating, and modeling microwave applications. The permittivity of stacked leaves of alfalfa (Medicago sativa ) were measured with a network analyzer and a coaxial probe, and the effect of moisture content (MC: 12%–73% wet basis), frequency (300 MHz to 18 GHz), bound water (Cole–Cole dispersion equation), temperature (-15\ ^\circ\C and 30 ^\circ\C), leaf-orientation, and pressure (0–11 kPa) were investigated. The measured permittivity increased with MC. A critical moisture level (CML) of 23% was reported, below which the permittivity decreased with increasing frequency at 22 ^\circ\C. Above CML and up to 5 GHz, the dielectric constants followed the Cole–Cole dispersion, and the dielectric loss factors consisted of ionic and bound water losses. Above 5 GHz, the behavior of the dielectric constant was similar to that of free water, and the polar losses became dominant. Above 0 ^\circ\C, the measured permittivity followed a trend similar to that of free saline water and was characterized by the Debye equation. Below 0 ^\circ\C, it was dominated by nonfreezing bound and unfrozen supercooled moistures. The relaxation parameters and the optimum pressure (9 kPa) for the leaf measurements were determined. The effects of variations among the samples, and their orientations had negligible effects on the measured permittivity. [ABSTRACT FROM PUBLISHER]

The successful operation of a tokamak fusion reactor rests on its ability to stably confine a very hot plasma. The quality of the discharge in the Saskatchewan TORus-Modified (STOR-M) tokamak is strongly related to the position of the plasma column within the discharge vessel. If the plasma column approaches too near the wall, then either minor or complete disruption occurs. Consequently it is necessary to be able to control dynamically the position of the plasma column throughout the entire discharge. A fuzzy-logic-based controller was designed and implemented for this purpose. This controller was evaluated on the STOR-M tokamak during actual operation, and was found to provide reliably a high quality of control. The actual performance of the fuzzy-logic-based controller at actually controlling the position of the plasma column within the STOR-M tokamak is evaluated against the actual performance of a proportional-integral-derivative (PID) controller. [ABSTRACT FROM AUTHOR]