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2003 IEEE LEOS Annual Meeting Conference Proceedings

作者： Lu, W. Small, B.A. Liboiron-Ladoucear, O. Kutz, J.N. Bergman, K. Department of Electrical Engineering Columbia University New York NY 10027 United States Department of Applied Mathematics University of Washington Seattle WA 98195 United States

Multi-hop routing of 10Gbit/sec optical packets through four complete nodes in the Data Vortex switch was demonstrated using bit-parallel WDM headers. Control signaling among four nodes was experimentally shown to pro... 详细信息

关键词： Fiber optic networks

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Optimization and implementation of extrapolated impulse response filters

Optimization and implementation of extrapolated impulse resp...

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2003 International Conference on Neural Networks and Signal Processing, ICNNSP'03

作者： Yu, Ya Jun Zhao, Guohui Teo, Kok Lay Lim, Yong Ching Electrical and Computer Engineering Department National University of Singapore Singapore 119260 Singapore Applied Mathematics Department Hong Kong Polytechnic University Hong Kong Hong Kong School of Electrical and Electronic Engineering Nanyang Technological University Singapore 639798 Singapore

ISBN: (纸本)0780377028

The impulse response of an FIR lowpass or highpass fitter is quasi-periodic and enclosed in an envelope with diminishing magnitude. Its energy concentrates near the center. This diminishing energy and quasi-periodic nature of the impulse response have been exploited in [1] to reduce the complexity of an FIR filter using a scheme called the extrapolated impulse response technique. In this paper, a semi-infinite programming is proposed to jointly optimize the filter coefficients and the extrapolated scaling factors. A realization structure making use of the coefficient symmetry is also presented. An example taken from literature is included illustrating that the number of multipliers for the resulting filter is less than 65 percent of existing results. © 2003 IEEE.

关键词： Impulse response

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Involving engineering with in-service K-4 teachers

Involving engineering with in-service K-4 teachers

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2003 ASEE Annual Conference and Exposition: Staying in Tune with engineering Education

作者： Swift, Theresa M. Watkins, Steve E. Swenson, Kristine Lasater, EvaLee Mitchell, Robert University of Missouri Rolla Department of Mathematics University of Missouri Rolla Applied Optics Laboratory Department of Electrical Engineering University of Missouri Rolla Department of English University of Missouri Rolla Department of Education University of Missouri Rolla School of Engineering

A strong workforce in science and engineering and literate citizens in a technology-based society depends on an educational system that prepares students in science, mathematics, and engineering. Unfortunately, many K-12 students lose interest in such topics early in their school years. engineering applications can capture the imagination of students and illustrate the concepts in science and mathematics. Level-appropriate resources are as necessary for primary teachers and our young scholars as for teachers and students in higher grades. A model for interaction between engineers and K-4 teachers is proposed. The State of Missouri defines curriculum standards in each subject area and assesses student performance three times during a student's education. The first assessment for science is in the third grade and for mathematics is in the fourth grade. These standards were examined from an engineering perspective. In addition, in-service primary teachers were surveyed to determine their background, needs, and attitudes regarding science, mathematics, and engineering. Early years of an effective technical curriculum must introduce the basic concepts and begin layering this understanding with detail and connectivity. Our model shows how engineering applications can provide hearing, seeing, and doing components, i.e. auditory, visual, and kinesthetic educational activities, within the recommended pedagogy. The approach involves in-service teachers throughout the development process, addresses state standards and testing criteria, and partners specialists in engineering content and teacher training.

关键词： engineering education

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A fundamental cross-layer approach to uplink resource allocation

A fundamental cross-layer approach to uplink resource alloca...

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MILCOM 2003 - 2003 IEEE Military Communications Conference

作者： Yeh, Edmund M. Cohen, Aaron S. Department of Electrical Engineering Yale University New Haven CT 06520 United States Division of Applied Mathematics Brown University Providence RI 02912 United States

The literature on multiaccess (uplink) communications has traditionally treated "network-layer" issues such as source burstiness and network delay apart from "physical-layer" issues such as channel modelling, coding, and detection. We establish a unified cross-layer framework for optimal resource allocation over multiaccess fading channels where packets arrive randomly to transmitters. Using optimal coding assumptions, we first show that the region of all stable arrival rates is the same as the information-theoretic capacity region of [1]. Next, we show that a Longest-Queue-Highest-Possible-Rate (LQHPR) allocation strategy stabilizes the multiaccess queueing system whenever stability is possible. Finally, we show that under symmetric conditions, the LQHPR policy also minimizes the average packet delay. Such a policy can be interpreted in the coding context as adaptive successive decoding. Since optimal coding assumptions are used, the throughput (delay) performance of the LQHPR policy provides a fundamental upper (lower) bound to the performance of all reliable multiaccess coding schemes.

关键词： Resource allocation

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Accurate Initialization of Neural Network Weights by Backpropagation of the Desired Response

Accurate Initialization of Neural Network Weights by Backpro...

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International Joint Conference on Neural Networks 2003

作者： Erdogmus, Deniz Fontenla-Romero, Oscar Principe, Jose C. Alonso-Betanzos, Amparo Castillo, Enrique Jenssen, Robert Electrical Engineering Department University of Florida Gainesville FL 32611 United States Department of Computer Science University of A Coruña 15071 A Coruña Spain Department of Applied Mathematics University of Cantabria 39005 Santander Spain

Proper initialization of neural networks is critical for a successful training of its weights. Many methods have been proposed to achieve this, including heuristic least squares approaches. In this paper, inspired by these previous attempts to train (or initialize) neural networks, we formulate a mathematically sound algorithm based on backpropagating the desired output through the layers of a multilayer perceptron. The approach is accurate up to local first order approximations of the nonlinearities. It is shown to provide successful weight initialization for many data sets by Monte Carlo experiments.

关键词： Neural networks

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PDE-based denoising of complex scenes using a spatially-varying fidelity term

PDE-based denoising of complex scenes using a spatially-vary...

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Proceedings: 2003 International Conference on Image Processing, ICIP-2003

作者： Gilboa, Guy Zeevi, Yehoshua Y. Sochen, Nir Department of Electrical Engineering Technion - Israel Inst. of Technol. Technion city Haifa 32000 Israel Department of Applied Mathematics University of Tel-Aviv Ramat-Aviv Tel-Aviv 69978 Israel

The widely used denoising algorithms based on nonlinear diffusion, such as Perona-Malik and total variation denoising, modify images toward piecewise constant functions. Though edge sharpness and location is well preserved, important information, encoded in image features like textures or small details, is often lost in the process. We suggest a simple way to better preserve textures, small details, or global information. This is done by adding a spatially varying fidelity term that controls the amount of denoising in any region of the image. This form is very simple, can be used for a variety of tasks in PDE-based image processing and computer vision, and is stable and meaningful from a mathematical point of view.

关键词： Image analysis

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Lightning protection of power systems using fuzzy logic techniques

Lightning protection of power systems using fuzzy logic tech...

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IEEE International Conference on Fuzzy Systems (FUZZ-IEEE)

作者： A.L. Orille S. Bogarra M.A. Grau J. Iglesias Department of Electrical Engineering/UPC Diagonal Barcelona 647 Department of Electrical Engineering/UPC Diagonal Barcelona 647 Spain Department of Applied Mathematics LIPC Barcelona Spain Department of Applied Mathematics/UPC Pau Gargallo Barcelona

As lightning surges are considered to be the most dangerous events in power distribution systems, the more we know about them the better we can select and coordinate protection devices. Moreover, a better knowledge of lightning surges gives rise to the accurate positioning of device protection, the reduction of insulation costs at installations and allows operation with well-known risks of failure. The development of a computer application based on fuzzy logic techniques, which allow the determination of the accurate position of the surge arrester in power systems, controls the risk of failure, thus permitting the selection of appropriate protection schemes for each network. As a consequence, protection costs are reduced in accordance with the costs of the elements actually protected and the continuity of service to be achieved.

关键词： Lightning protection Power system protection Fuzzy logic Surge protection Costs Power distribution Insulation Computer applications Arresters Power system control

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A transform potential-theoretic method for acoustic radiation from structures

A transform potential-theoretic method for acoustic radiatio...

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44th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

作者： Hariharan, S.I. Sawyer, Scott The University of Akron Dept. of Electrical and Comp. Eng. Division of Applied Mathematics Akron OH 44325 United States The University of Akron Department of Mechanical Engineering Akron OH 44325 United States

ISBN: (纸本)9781624101007

This paper presents further development in a new time domain computational technique developed for the determination of far field acoustic radiation. This method, referred to as the Transform Potential Theoretic Method (TPT), solves linear time dependent wave propagation in an unbounded medium combining techniques involving numerical transforms/inverse transforms and potential theory. The end result is a robust procedure that is accurate and computationally efficient. The TPT technique is meshless yet it can handle arbitrary geometries for the acoustic source. The validity of the procedure is demonstrated for the case of an acoustic wave propagation from a two-dimensional bounded surface embedded in a uniform flow. Both direct simulations as well as the current method(s) are compared. The single layer potential theory based TPT method required fewer points on the boundary than the double layer potential theory based TPT, and performs better than direct simulation in high subsonic Mach number flows (M = 0.8). The time required to compute these solutions were more than two orders of magnitude lower than direct simulation.

关键词： Aerospace engineering

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Nonlinear optical effects in a two-dimensional photonic crystal containing one-dimensional Kerr defects

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Physical Review E 2003年第5期67卷 056604-056604页

作者： M. Bahl N.-C. Panoiu R. M. Osgood, Jr. Department of Electrical Engineering Columbia University New York New York 10027 Department of Applied Physics and Applied Mathematics Columbia University New York New York 10027 Brookhaven National Laboratories Upton New York 11973

The nonlinear optical effects induced by a one-dimensional (1D) line defect, made of Kerr material, in a 2D photonic crystal are studied. Comprehensive ab initio numerical simulations based on the finite-difference time-domain method show efficient third-harmonic generation in a photonic crystal waveguide consisting of the 1D defect line. The relationship between the third harmonic generation process and the nonlinear modal properties of the waveguide is discussed. We investigate optical limiting in such a device, that is, control of the transmitted power as a function of the Kerr-induced variation of the refractive index. Power dependent spectral changes in such a device and its use as a frequency selector are also examined.

关键词： Nonlinear optics

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Fuzzy logic techniques to limit lightning surges in a power transformer

Fuzzy logic techniques to limit lightning surges in a power ...

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Power Tech Conference

作者： A.L. Orille S. Bogarra M.A. Grau J. Iglesias Department of Electrical Engineering Polytechnic University of Catalonia Barcelona Spain Department of Applied Mathematics Polytechnic University of Catalonia Barcelona Spain

Lightning surges can cause major damage to distribution network components, specially to transformers, therefore it is important to select an appropriate protection scheme to limit the damage caused by these overvoltages. The purpose of this work is the development of a method to calculate the surge arrester position in distribution systems, using fuzzy logic techniques, in order to establish failure risks lower than the admissible and to install the least number of arresters. The development of a computer application using the Matlab program allows the determination of the accurate position of the surge arrester in power systems, controls the risk of failure, thus permitting the selection of appropriate protection schemes for each network. We can reach important conclusions of the transformer protection using simplified models in the network analysis.

关键词： Fuzzy logic Lightning Power transformers Surge protection Power system protection Arresters Power system modeling Computer applications Power system analysis computing Power system control

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