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Why doesn't everyone use it?

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JOURNAL OF CLINICAL LASER MEDICINE & SURGERY 2003年第6期21卷 335-336页

作者： Lanzafame, RJ

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The Method of Vibration Control in the Points of Continuous Flexible Systems

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Systems Analysis Modelling Simulation 2003年第3期43卷 361-369页

作者： W. Wodzicki J. Awrejcewicz Department of Automatics and Biomechanics Technical University of Lodz 1/15 Stefanowski St. Lodz 90-924 Poland

A continuous flexible system harmonically excited is considered. Minimization of vibration in chosen points of the flexible system is realized by means of joining an additional system characterized by suitable receptances, which have to be calculated. The paper presents the method of determining the appropriate receptances of additional system in order to cancel vibrations in the mentioned points of the main system.

关键词： Vibration Control Continuous Flexible Systems computational algorithm

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Bootstrapping the lexicon: A computational model of infant speech segmentation

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COGNITION 2002年第2期83卷 167-206页

作者： Batchelder, EO CUNY Grad Ctr New York NY USA

Prelinguistic infants must find a way to isolate meaningful chunks from the continuous streams of speech that they hear. BootLex, a new model which uses distributional cues to build a lexicon, demonstrates how much can be accomplished using this single source of information. This conceptually simple probabilistic algorithm achieves significant segmentation results on various kinds of language corpora - English, Japanese, and Spanish: child- and adult-directed speech, and written texts;and several variations in coding structure - and reveals which statistical characteristics of the input have an influence on segmentation performance. BootLex is then compared, quantitatively and qualitatively, with three other groups of computational models of the same infant segmentation process, paying particular attention to functional characteristics of the models and their similarity to human cognition. Commonalities and contrasts among the models are discussed, as well as their implications both for theories of the cognitive problem of segmentation itself, and for the general enterprise of computational cognitive modeling. (C) 2002 Elsevier Science B.V. All rights reserved.

关键词： speech segmentation infants computational algorithm probabilistic cues cognitive models

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Exact equation and an algorithm for reliability evaluation of K-out-of-N:G system

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RELIABILITY ENGINEERING & SYSTEM SAFETY 2002年第2期78卷 87-91页

作者： Arulmozhi, G PSG Coll Technol Dept Math & Comp Applicat Coimbatore 641004 Tamil Nadu India

An expression for reliability of K-out-of-N:G system is proposed. An algorithm for computing reliability of K-out-of-N system is given. It is an easy to implement, fast and memory efficient algorithm and helps to impr... 详细信息

关键词： K-out-of-N : G system reliability recursive function computational algorithm

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Solving posynomial geometric programming problems via generalized linear programming

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computational OPTIMIZATION AND APPLICATIONS 2002年第1期21卷 95-109页

作者： Rajgopal, J Bricker, DL Univ Pittsburgh Dept Ind Engn Pittsburgh PA 15261 USA Univ Iowa Dept Ind Engn & Management Iowa City IA 52242 USA

This paper revisits an efficient procedure for solving posynomial geometric programming (GP) problems, which was initially developed by Avriel et al. The procedure, which used the concept of condensation, was embedded within an algorithm for the more general (signomial) GP problem. It is shown here that a computationally equivalent dual-based algorithm may be independently derived based on some more recent work where the GP primal-dual pair was reformulated as a set of inexact linear programs. The constraint structure of the reformulation provides insight into why the algorithm is successful in avoiding all of the computational problems traditionally associated with dual-based algorithms. Test results indicate that the algorithm can be used to successfully solve large-scale geometric programming problems on a desktop computer.

关键词： geometric programming column generation linearization nonlinear optimization computational algorithm

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Three improvements in reduction and computation of elliptic integrals

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JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY 2002年第5期107卷 413-418页

作者： Carlson, BC Iowa State Univ Ames Lab Ames IA 50011 USA Iowa State Univ Dept Math Ames IA 50011 USA

Three improvements in reduction and computation of elliptic integrals are made. 1. Reduction formulas, used to express many elliptic integrals in terms of a few standard integrals, are simplified by modifying the definition of intermediate "basic integrals." 2. A faster than quadratically convergent series is given for numerical computation of the complete symmetric elliptic integral of the third kind. 3. A series expansion of an elliptic or hyperelliptic integral in elementary symmetric functions is given, illustrated with numerical coefficients for terms through degree seven for the symmetric elliptic integral of the first kind. Its usefulness for elliptic integrals, in particular, is important.

关键词： computational algorithm elementary symmetric function elliptic integral hyperelliptic integral hypergeometric R-function recurrence relations series expansion

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Experimental crack identification using electrical impedance tomography

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NDT & E INTERNATIONAL 2002年第5期35卷 301-316页

作者： Lazarovitch, R Rittel, D Bucher, I Technion Israel Inst Technol Fac Mech Engn IL-32000 Haifa Israel

This paper addresses the problem of practical crack identification in electrically conducting specimens using only boundary measurements. The method is commonly referred to in the literature as Electrical Impedance Tomography (EIT). Crack identification is determined from the electrical impedance distribution, which amounts to solving an inverse problem, starting from boundary measurements. Whereas this kind of inverse problem has been extensively addressed in its theoretical and numerical aspects, there is a scarcity of experimental results aimed at examining the applicability of the method for real conditions. We present new experimental results, based on a simple identification methodology. The efficiency and limitations of this method are assessed through a series of numerical simulations and laboratory experiments on two-dimensional geometries. Following a preliminary numerical validation stage, actual crack detection is carried out on a discrete network of resistors, as an approximation to Laplace's equation. Next, experiments are carried out on a continuous conductive medium, containing one and two flaws. Our results show, that EIT is a promising candidate for crack identification in real life conditions with a potential for multiple crack detection. (C) 2002 Elsevier Science Ltd. All rights reserved.

关键词： conductance computational algorithm homogeneous medium

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Conservative and oscillation-less atmospheric transport schemes based on rational functions

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JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 2002年第D22期107卷 ACL 2-1-ACL 2-11页

作者： Xiao, F Yabe, T Peng, X Kobayashi, H Tokyo Inst Technol Dept Energy Sci Midori Ku Yokohama Kanagawa 2268502 Japan Tokyo Inst Technol Dept Engn Sci & Mech Meguro Ku Tokyo 1528552 Japan JAMSTEC Earth Simulator Ctr Yokohama Kanagawa 2360001 Japan

In this paper, we present two practical schemes for advection transport equation. The schemes, namely Conservative Semi-Lagrangian with Rational function (CSLR0) and CSLR1, are two new variants of the Constrained Interpolation Profile-Conservative Semi-Lagrangian (CIP-CSL) type methods [Yabe et al., 2001]. In these schemes, the subgrid profile is approximated within a single cell by rational interpolation functions. Both the cell-integrated average and the values at the two cell interfaces are employed for the interpolation construction. The interface value is computed through a semi-Lagrangian procedure, while the cell-integrated quantity is advanced via a flux form formulation that is equivalent to a mass conservative remapping. The schemes are exactly conservative with regards to the cell integration of the advected quantity and have quite small dispersion and diffusion errors. The rational interpolations suppress spurious oscillation, and a continuous profile with a smoothness of at least C-0 can be obtained over the whole computational domain. Without any explicit computation of flux or slope limiter, the schemes are more computationally efficient than the piecewise parabolic method (PPM) scheme in the context of 1D. Our numerical tests show that the presented schemes are comparable to the PPM method with regards to numerical dispersion, clipping, and shape preserving.

关键词： atmospheric transport computational algorithm rational interpolation numerical oscillation mass conservation

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Improved SAR target detection via extended fractal features

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IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS 2001年第2期37卷 436-451页

作者： Kaplan, LM Clark Atlanta Univ Ctr Theoret Studies Phys Syst Dept Engn Atlanta GA 30314 USA

The utility of the extended fractal (EF) feature is evaluated for the enhancement of the focus of attention (FOA) stage of a synthetic aperture radar (SAR) automatic target recognition (ATR) system. Unlike more traditional SAR detection features that distinguish target pixels from the background only on the basis of contrast, the EF feature is sensitive to both the contrast and size of objects. Furthermore, the structure for the EF feature computational algorithm lends itself to very fast implementation, and it can be shown that the new feature has a CFAR-like (constant false alarm rate) property. We demonstrate the improved performance using the new feature by testing a number of different detection approaches over two databases of SAR imagery.

关键词： feature extraction fractals radar imaging radar target recognition synthetic aperture radar SAR imaging SAR target detection automatic target recognition computational algorithm constant false alarm rate extended fractal feature focus of attention synthe END FITTING Radar polarimetry Radar target recognition focused attention Automatic target recognition Radar imaging Fractals constant false alarm rate Feature extraction Rescue Specific absorption rate

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Exactly conservative semi-Lagrangian scheme for multi-dimensional hyperbolic equations with directional splitting technique

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JOURNAL OF computational PHYSICS 2001年第1期174卷 171-207页

作者： Nakamura, T Tanaka, R Yabe, T Takizawa, K Utsunomiya Univ Dept Elect & Elect Engn Utsunomiya Tochigi 3218585 Japan Tokyo Inst Technol Dept Energy Sci Midori Ku Yokohama Kanagawa 2268502 Japan Tokyo Inst Technol Dept Mech Engn & Sci Meguro Ku Tokyo 1528552 Japan

A new numerical method that guarantees exact mass conservation is proposed to solve multidimensional hyperbolic equations in semi-Lagrangian form. The method is based on the constrained interpolation profile (CIP) scheme and keeps the many good characteristics of the original CIP scheme. The CIP strategy is applied to the integral form of variables. Although the advection and nonadvection terms are separately treated, mass conservation is kept in the form of a spatial profile inside a grid cell. Therefore, it retains various advantages of the semi-Lagrangian solution with exact conservation, which has been beyond the capability of conventional semi-Lagrangian schemes. (C) 2001 Elsevier Science.

关键词： computational algorithm CIP-CSL2 R-CIP-CSL2 semi-Lagrangian mass conservation multi-dimensions cubic interpolation monotone preserving

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