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A RIGOROUS MODEL FOR RADIATED EMISSION PREDICTION IN PCB CIRCUITS

IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY 1993年第1期35卷 102-109页

作者： CERRI, G DELEO, R PRIMIANI, VM Dipartimento di Elettronica ed Automatica Università di Ancona Ancona Italy Dipartimento di Elettronica ed Autom. Ancona Univ. Italy

The problem of the radiated emission from printed circuit boards (PCB) is theoretically and experimentally investigated. Differential mode and common mode currents are separately studied by means of a rigorous method based on proper Green's functions. The solution of the integral equations for the current distribution, derived from the problem formulation, is numerically achieved by the method of moments (MOM). Simulated results are in good agreement with measurements. The final products of this study are masks that establish the maximum allowable current or voltage values as a function of frequency to comply with CISPR regulation.

关键词： Predictive models Current distribution Geometry Transmission line theory Solid modeling Crosstalk Printed circuits Integral equations Moment methods message-oriented middleware

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A general purpose fuzzy controller for monotone functions

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IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS PART B-CYBERNETICS 1996年第5期26卷 803-808页

作者： Wu, CJ Sung, AH NEW MEXICO INST MIN & TECHNOL DEPT COMP SCISOCORRONM 87801

In this work, a general purpose fuzzy controller is proposed to handle the class of monotone functions, A set of rules on the selection of fuzzy subsets and decision tables based on the mean-of-inversion (MOI) defuzzification method for guaranteed convergence and accuracy is given and proved. Unlike the mean-of-maximum (MOM) and the center-of-area (COA) methods, the MOI method defuzzifies each fired rule separately instead of superimposing fired rules before defuzzification.

关键词： Fuzzy control Fuzzy sets Convergence Control systems Analytical models Stability analysis Fuzzy systems Computer science message-oriented middleware Fuzzy logic

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TRANSIENT CURRENT ON A WIRE PENETRATING A CAVITY-BACKED CIRCULAR APERTURE IN AN INFINITE SCREEN

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IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY 1990年第3期32卷 197-204页

作者： WRIGHT, DB LEE, R DUDLEY, DG SANDIA NATL LABS ALBUQUERQUENM 87185

The problem of a wire penetrating a circular aperture in an infinite conducting screen and entering a circular cylindrical cavity is considered. Results for the transient current propagating along the wire both inside and outside the cavity are presented. The current in both regions is evaluated in the frequency domain by the method of moments (MOM). An approximate method for evaluating the exterior current at an observation point far from the aperture is discussed. To obtain the transient response, a numerical inverse Fourier transform is used. The current response is examined as a function of cavity and aperture dimensions. Results obtained with the approximate method are compared with the MOM solution. It appears that information concerning the interior cavity dimensions is present in these exterior observations.< >

关键词： Wire Apertures Frequency domain analysis Region 1 Laplace equations message-oriented middleware Geometry Region 2 Maxwell equations Moment methods

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USE OF REDUNDANT TESTING FUNCTIONS IN MOMENT-METHOD SOLUTIONS FOR BLOCK-MODELS

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IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 1993年第2期41卷 305-310页

作者： CAORSI, S GRAGNANI, GL PASTORINO, M UNIV GENOA INTERACT ELECTROMAGNET FIELDS & BIOL SYST RES CTRI-16145 GENOAITALY

An overconstrained version of the method of moments for SAR evaluation in biological bodies is presented. A number of testing functions larger than the one of basis functions is used in order to better constrain the solution near corners and edges. A rectangular system is obtained that is solved by means of a pseudoinversion algorithm. Comparisons with results reported in the literature are made, showing an enhancement of the MoM capabilities in SAR calculations, without a consistent increase in computational requirements.

关键词： Testing Moment methods Biology computing Biological system modeling Dielectrics message-oriented middleware Electromagnetic scattering Distributed computing Electromagnetic fields Electromagnetic radiation

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ON THE USE OF REGULARIZATION TECHNIQUES IN NUMERICAL INVERSE-SCATTERING SOLUTIONS FOR MICROWAVE IMAGING APPLICATIONS

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IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 1995年第3期43卷 632-640页

作者： CAORSI, S CIARAMELLA, S GRAGNANI, GL PASTORINO, M UNIV GENOA DEPT BIOPHYS & ELECTR ENGNICEMBI-16145 GENOAITALY UNIV GENOA DEPT BIOPHYS & ELECTR ENGNAPPL ELECTROMAGNET LABI-16145 GENOAITALY

This paper deals with integral-equation-based numerical methods for microwave imaging using regularization procedures to overcome ill-conditioning problems, The strong dependence of reconstruction quality on ''a priori'' information is discussed. Such information is required to select a suitable number of independent columns when using truncated pseudoinversions (or other regularization parameters, in different cases) for accurate dielectric reconstructions. Moreover, a criterion for the choice of the optimal number of independent columns is proposed, and the possibility of making this choice less critical by using a multiview version of the method is explored. Finally, a modified procedure is presented that further increases the range from which to choose the number of independent columns that allows one to achieve acceptable reconstructions.

关键词： Microwave theory and techniques Image reconstruction Dielectrics Microwave imaging Inverse problems Scattering message-oriented middleware Integral equations Diffraction

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Generalized defuzzification strategies and their parameter learning procedures

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IEEE TRANSACTIONS ON FUZZY SYSTEMS 1996年第1期4卷 64-71页

作者： Jiang, T Li, Y NEC RES INST PRINCETONNJ 08540

Defuzzification is a procedure of crucial importance for fuzzy systems because a final crisp output (control) action is required in many theoretical and practical applications. The choice of defuzzification strategy, therefore, can directly affect the success of such applications. Among the existing strategies, neither the center of area (COA) nor the mean of maximum (MOM) emerges as the better defuzzification strategy. A compromise strategy that combines the two methods may offer a synergetic solution. In this paper, we introduce two new objective defuzzification strategies, Gaussian distribution transformation-based defuzzification (GTD) and polynomial transformation-based defuzzification (PTD), which are based on a discrete universe of discourse. Both strategies can perform better than the existing strategies and the PTD strategy offers a generalized defuzzification tool for a wide class of practical problems. Both strategies include the COA and MOM strategies as special cases, and both are based on parameter learning processes using the extended Kalman filter as their iterative improvement algorithms on sample database containing fuzzy sets and the associate defuzzified values. The proposed parameter learning procedures are capable of either off-line or on-line processing.

关键词： message-oriented middleware Fuzzy sets Fuzzy systems Fuzzy control Gaussian distribution Polynomials National electric code Control systems Iterative algorithms Transaction databases

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A BLOCK ITERATIVE TECHNIQUE TO EXPAND MMPS APPLICABILITY TO EM PROBLEMS OF HIGHER COMPLEXITY

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IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 1994年第5期42卷 875-883页

作者： KUSTER, N BOMHOLT, LH Swiss Federal Institute of Technology Zurich Switzerland

The present multiple multipole (MMP) approach exhibits limitations with problems of higher complexity. Its dense and strongly overdetermined system of equations is badly conditioned even for smaller problems such that only expensive, more stable QR decomposition methods can generally be applied. With growing complexity and size of the problem, the matrix often becomes near-rank deficient. Additionally, the performed row and column weighting is unsatisfactory if the averaged power density values vary strongly throughout the boundaries. Some of these limitations can be avoided by using the iterative technique introduced here. It is shown that these systems of equations can easily be built and partitioned according to physical considerations in such a way that diagonally dominant block matrices are obtained. For many problems, a few block Gauss-Seidel or successive block overrelaxation (SBOR) steps produce a sufficiently converged solution. Even more significant than the numerical advantage is the fact that this technique opens new possibilities for the modeling and the validation of solutions and therefore considerably facilitates and extends the applicability of the MMP code to a larger spectrum of problems. Furthermore, the alternating procedure presents new possibilities for directly coupling MMP with other codes, such as finite difference (FD) and method of moments (MoM).

关键词： Equations Iterative methods Jacobian matrices Gaussian processes Finite difference methods Sparse matrices Piecewise linear approximation Matrix decomposition Moment methods message-oriented middleware

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INACCURACIES IN NUMERICAL-CALCULATION OF SCATTERING NEAR NATURAL FREQUENCIES OF PENETRABLE OBJECTS

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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 1993年第7期41卷 982-986页

作者： HOWER, GL OLSEN, RG EARLS, JD SCHNEIDER, JB School of Electrical Engineering and Computer Science Washington State University Pullman WA USA

Calculated scattering from a nonconducting cylindrical ring shows great variability to small changes in the material or geometric parameters within certain ranges of these parameters. The observations are explained by a resonance phenomenon in which the operating frequency is found to lie close to a complex natural frequency of the scattering object. Note that this resonance is a real, observable effect predicted by analytical solutions and not the ''spurious'' numerical resonances which have been widely discussed and which one wishes to suppress. Attempts have been made to reproduce near resonance scattering results using the method of moments and finite-difference time-domain codes. These have failed despite the use of widely accepted discretization densities. Thus, the existence of such resonances requires additional care when interpreting computed results for scattering from similar nonconducting objects having electric and/or magnetic properties.

关键词： Frequency Scattering parameters Magnetic resonance Moment methods Magnetic properties Polarization Integral equations message-oriented middleware Permittivity Engine cylinders

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ON THE DISCRETE RICCATI EQUATION

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IEEE TRANSACTIONS ON AUTOMATIC CONTROL 1987年第9期32卷 828-829页

作者： MORI, T FUKUMA, N KUWAHARA, M KYOTO UNIV EDUC KYOTO 612JAPAN

Several bounds have been reported recently for the trace of the solution to the discrete algebraic matrix Riccati equation. This note adds an alternative one to them.

关键词： Riccati equations Polynomials Linear systems Matrices Sufficient conditions message-oriented middleware Process control Signal processing Arithmetic Eigenvalues and eigenfunctions

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MMP METHOD SIMULATION OF ANTENNAE WITH SCATTERING OBJECTS IN THE CLOSER NEARFIELD

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IEEE TRANSACTIONS ON MAGNETICS 1989年第4期25卷 2881-2883页

作者： KUSTER, N BALLISTI, R Swiss Federal Institute of Technology Zurich Switzerland

The advantages and limits of the multiple multipole (MMP) method applied to problems of antennas with lossy scattering objects in the very close near field are discussed. Difficulties occur because of the concentrated sources that produce high-gradient fields. The capability of the program is shown by two examples: a simulation of a radio held by a man and of an antenna embedded in lossy brain tissue. It is concluded that near and far fields, antenna impedance, absorbed power, and other parameters can be calculated with high accuracy. To overcome some of the limitations of the MMP it needs to be combined with a finite-element or finite-difference approach.< >

关键词： Scattering Iron message-oriented middleware Biological system modeling Brain modeling Computational modeling Humans Maxwell equations Antenna measurements Hyperthermia

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