A class of gradient based adaptive algorithms is presented which employs order-statistical transformations of the gradient estimates over a short window. These algorithms, called order-statistical least mean squares (...
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A class of gradient based adaptive algorithms is presented which employs order-statistical transformations of the gradient estimates over a short window. These algorithms, called order-statistical least mean squares (OSLMS), are designed to facilitate adaptive filter performance close to the least-squares optimum in impulsive and other non-Gaussian input environments. Three specific OSLMS filters are defined: the median LMS, the averaged LMS, and the trimmed-mean LMS. For the median LMS some simple convergence results are given. Simulations of all three algorithms, conducted using a generalized exponential density, are presented.< >
We have developed a conceptual framework and a demonstration system that contextualize (or situate) learning in the context of real-world work situations. The conceptual framework is based on the following requirement...
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Unique localization of multiple sources by antenna arrays requires that the number of sensors be greater than the number of sources. When additional information is given this is no longer true. The authors assumed a s...
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Unique localization of multiple sources by antenna arrays requires that the number of sensors be greater than the number of sources. When additional information is given this is no longer true. The authors assumed a signal structure of the autoregressive (AR) type. A localization procedure is presented which consists of two stages; in the first stage the coefficients of the AR signals are estimated, while in the second stage the directions of arrival are estimated. Simulation results demonstrate the performance of the algorithm under different scenarios.< >
An improved version of the Papoulis algorithm for bandlimited signal interpolation is presented. This algorithm uses the concept of initial interpolation. The justification for initial interpolation is developed only ...
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An improved version of the Papoulis algorithm for bandlimited signal interpolation is presented. This algorithm uses the concept of initial interpolation. The justification for initial interpolation is developed only through experimental studies. It is shown that the performance of the interpolation scheme depends on the number and distribution of the known data samples.< >
Often the existence of reverberations in the ultrasonic pulse-echo imaging of multilayered structure prevents the direct characterization of each layer. The reverberating pattern is governed by the integrity of the la...
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Often the existence of reverberations in the ultrasonic pulse-echo imaging of multilayered structure prevents the direct characterization of each layer. The reverberating pattern is governed by the integrity of the layers, and deterioration of these layers can generate complex and unpredictable patterns. Analytical models for the classification of reverberant patterns using both normal and unique angle scanning schemes are presented. The theoretical model has been utilized in the experimental studies of a particular multilayered reverberant environment that exists in the detection of corrosion and/or volatile changes in stem generator tubing used in nuclear power plants. Various reverberant patterns can be recognized that are in close agreement with theoretical predictions.
Image segmentation can be a useful tool in facing image degradation. In image segmentation the input is a set of pixels with given grey levels and the output is a partition of the set of pixels into connected regions ...
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This paper addresses the effects of fast dynamics on direct energy methods that use a sustained fault trajectory to approximate critically cleared trajectories and the corresponding critical energies. Integral manifol...
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The authors predict the gain performance for a CP-RLSA (circularly polarized radial line slot antenna) with reduced slot coupling and propose a basic design for slot coupling control (SCC). When the CP-RLSA can be use...
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The authors predict the gain performance for a CP-RLSA (circularly polarized radial line slot antenna) with reduced slot coupling and propose a basic design for slot coupling control (SCC). When the CP-RLSA can be used near the resonant frequency with weak coupling, the bandwidth becomes 1.5 times as wide as that of an antenna without SCC. SCC for this purpose is possible by the determination of the slot coupling angle. The proposed design was verified experimentally.< >
A method for the high-precision torque control of a reluctance motor for servo applications is presented. The prototype is a three-phase, eight-pole reluctance motor driven by a MOSFET inverter. The current control as...
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A method for the high-precision torque control of a reluctance motor for servo applications is presented. The prototype is a three-phase, eight-pole reluctance motor driven by a MOSFET inverter. The current control as well as the speed control is performed by the software of a digital signal processor. The motor is supplied with sinusoidal current, and two current control methods are proposed. One is based on the vector control principle to achieve linearity between current and torque, and another is developed to obtain the maximum torque/current ratio. Due to the saliency, the inst.ntaneous torque contains a large ripple component. In the case of the test motor, the ripple torque was as much as 26% of the rated torque under the sinusoidal current drive. Experimental results show that the ripple component could be reduced to 6% by superimposing the compensation current component on the current reference.< >
In the LN-PC hybrid technique, numerical analysis method for microstrip patch antennas of arbitrary shape, the regions under and outside of the patch are solved separately by means of the theory for planar circuits (P...
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In the LN-PC hybrid technique, numerical analysis method for microstrip patch antennas of arbitrary shape, the regions under and outside of the patch are solved separately by means of the theory for planar circuits (PC) and the theory for linear antennas (LN), respectively, and the two solutions are matched at the boundary. Although it leads to reasonably good results, more elaborate studies are desired concerning the patch edge and the coaxial cable to a planar circuit junction. The latter problem is dealt with, and the F-matrix representation of the junction is presented together with a few numerical examples. The input impedance is calculated by means of the present theory for a circular microstrip antenna.< >
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