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Spectral comp.rison between the second and the fourth order equations of conservative type with non-local terms

Japan Journal of Industrial and Applied Mathematics 1998年第2期15卷 253-262页

作者： Ohnishi, Isamu Nishiura, Yasumasa Dept. of Comp. Sci. and Info. Math. Faculty of Electro-Communications University of Electro-Communications Chofu-ga-oka Chofu Tokyo 182 Japan Lab. Nonlinear Studs. Computation Res. Inst. for Electronic Science Hokkaido University Kita-ku Sapporo 060 Japan

We present a spectral comp.rison theorem between the second and the fourth order equations of conservative type with non-local terms. Nonlocal effects arise naturally due to the long-range spatial connectivity in polymer problems or to the difference of relaxation times for phase separation problems with stress effect. If such nonlocal effects are built into the usual Cahn-Hilliard dynamics, we have the fourth order equations with nonlocal terms. We introduce the second order conservative equations with the same nonlocal terms as the fourth order ones. The aim is to show that both the second and the fourth order equations have the same set of steady states and their stability properties also coincide with each other. This reduction from the fourth order to the second order is quite useful in applications. In fact a simple and new proof for the inst.bility of n-layered solution of the Cahn-Hilliard equation is given with the aid of this reduction.

关键词： Critical eigenvalues Spectral comp.rison The Cahn-Hilliard equations The conservative reaction diffusion equations Variational method

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Fast Feature-Based Metamorphosis and Operator Design

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comp.ter Graphics Forum 1998年第3期17卷 C14-C22页

作者： Lee, Tong-Yee Lin, Young-Ching Lin, Leeween Sun, Y.N. Dept. of Comp. Sci. and Info. Eng. Natl. Cheng-Kung University Tainan Taiwan Taiwan Inst. of Comp. and Info. Engineering National Sun Yat-Sen Univ. Kaohsiung Taiwan

Metamorphosis is a powerful visual technique, for producing interesting transition between two images or volume data. Image or volume metamorphosis using simple features provides flexible and easy control of visual effect. The feature-based image warping proposed by Beier and Neely is a brute-force approach. In this paper, first, we propose optimization methods to reduce their warping time without noticeable loss of image quality. Second, we extend our methods to 3D volume data and propose several interesting warping operators allowing global and local metamorphosis of volume data.

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Embedded system design using soft-core processor and valen-C (vol 14, pg 602, 1998)

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JOURNAL OF INFORMATION sci.NCE AND ENGINEERING 1998年第4期14卷 693-693页

作者： Yasuura, H Tomiyama, H Dept. of Comp. Sci. Commun. Eng. Grad. Sch. Info. Sci. Elec. Eng. Kyushu University Fukuoka 816-8580 Japan Dept. of Comp. Sci. and Commun. Eng. Grad. Sch. Info. Sci. and Elec. Eng. Kyushu University Japan Inst. of Syst. and Info. Technol. KYUSHU Fukuoka Japan Kyoto University Kyoto Japan Kyoto University Japan Kyushu University Japan University of California Berkeley United States

A new design methodology of embedded systems based on a user defined application specific processor, called a soft-core processor, and a new programming language, Valen-C, is proposed. In the initial design phase, a designer designs a system with a soft-core processor, RAM, ROM and logic circuits. Software on the system is written in Valen-C, in which the designer can specify the word length of each variable required tor accurate comp.tation in the program. After verifying the functionality of the initial design, we can optimize the system by changing several parameters of the soft-core processor. The total area of a system including the soft-core processor, ROM and RAM can be optimized by changing the word length. The proposed design method enables the designer to tune up the processor architecture for his application easily.

关键词： Core Processors Datapath Width Embedded Systems RAM Retargetable comp.ler ROM System Optimization

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A Flexible 200 GOPS HDTV Motion Estimation Chip

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Journal of VLSI Signal Processing Systems for Signal, Image, and Video Technology 1998年第2期19卷 85-95页

作者： Berns, Jan Peter Noll, Tobias G. Dept. of Elec. Eng. and Comp. Syst. University of Technology RWTH Aachen Germany University of Technology RWTH Aachen Germany Inst. of Elec. Eng. and Comp. Syst. University of Technology RWTH Aachen Germany ASIC Design Centre Toshiba Electronics Europe Germany Fachhochschule Koblenz Germany Technical University of Munich Germany Ruhr-University of Bochum Germany Max-Planck-Inst. of Radio Astronomy Bonn Germany MOS Integrated Circuits Department MOS Des. Team Trainee Prog. S. Munich Germany Corp. R. and D. Dept. of Siemens Germany Electrical Engineering Faculty University of Technology RWTH Aachen Germany Dept. of Elec. Eng. and Comp. Syst. Sci. and Tech. Advisory Committee Supervisory Bd. Forschungszentrum J. JÜlich Germany Department on Microelectronics

A flexible block matching motion estimation chip is described. The block size can be adaptively refined for variable size block matching algorithms with blocks of 8 × 8, 16 × 16 and 32 × 32 pixels or can be set to one of these sizes without significant loss in efficiency. The chip performs block matching on a search area of ±15 vertically and horizontally for a block size of 32 × 32 pixel. For larger search areas of, e.g., ±128 horizontally and ±32 vertically identical devices can be cascaded. Full search can be processed as well as other fast search strategies with an additional external RAM and a standard RISC processor. Sub-pel precision motion vectors can be derived using a smaller search area or cascading identical devices. The chip performes more than 200 GOPS on a die size of 220 mm² in a 0.5-μm CMOS technology. With an additional masking unit the processor is prepared for future object or region-based algorithms.

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Experiments with learning techniques for spatial model enrichment and line generalization

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GeoInformatica 1998年第4期2卷 315-333页

作者： Plazanet, Corinne Bigolin, Nara Martini Ruas, Anne EPFL - Swiss Fed. Inst. Technol. L. Database Laboratory CH-1015 Lausanne Switzerland University of Paris VI LIP6 Laboratory 75 252 Paris Cedex 05 France Inst. Géographique National COGIT Laboratory 94160 Saint-Mandé France Comp. Sci. Applied to Earth Sciences University of Jussieu Paris France Parisian Transportation Company Switzerland French National Mapping Agency France Ital. Inst. of Applied Mathematics Genova Italy Database Laboratory Swiss Fed. Inst. Technol. Lausanne Switzerland Fed. University of Rio Grande do Sul Brazil University of Paris VI France COGIT Laboratory France OEEPE France

The nature of map generalization may be non-uniform along the length of an individual line, requiring the application of methods that adapt to the local geometry and the geographical context. Geographical databases need to be enriched in terms of shape description structures (geometrical knowledge), knowledge of appropriate order of operations and of appropriate algorithms (procedural knowledge). Stored knowledge should take account of semantic and morphological characteristics, and of cartographic constraints. This paper proposes and discusses three experiments on knowledge acquisition using unsupervised and supervised learning techniques. In order to exploit geometrical shape knowledge, classifications were comp.ted according to a set of morphological measures using unsupervised learning. Choice of appropriate operations was determined by the results of a test with IGN cartographers considering line characteristics. These results were given to a supervised learning algorithm, along with corresponding comp.ted measures in order to discover rules. The approach and the resulting rules are presented and discussed. Tests have also been conducted on the tuning of parameter values, applying a Gaussian smoothing tolerance value to a set of lines using the supervised learning algorithm. The values obtained by means of the learning algorithm have been comp.red with interactive choices of an expert. Results are promising with a prediction rate higher than 80% having been obtained.

关键词： Clustering Generalization Knowledge acquisition Machine learning Shape modeling

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Bromine ion-beam-assisted etching of InP and GaAs

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Journal of Vacuum sci.nce & Technology B: Microelectronics Processing and Phenomena 1998年第3期16卷 1012-1012页

作者： Rossler, J.M. Royter, Y. Mull, D.E. Goodhue, W.D. Fonstad, C.G. Dept. of Physics and Applied Physics University of Massachusetts Lowell Lowell MA 01854 United States Dept. of Elec. Eng. and Comp. Sci. Massachusetts Inst. of Technology Cambridge MA 02139 United States Lincoln Laboratory Massachusetts Inst. of Technology Lexington MA 02173 United States

Bromine ion-beam-assisted etching produces smooth vertical sidewalls in GaAs wafers with substrate temperatures in the range of 20-200°C and smooth vertical sidewalls in InP wafers with substrate temperatures in the range of 150-200°C. Etch rates can be varied from several nm/min to 0.16 μm/min through the bromine flow rate, Ar⁺ ion beam density and energy, and the substrate temperature. The etching rate ratios of bromine-only etching (no Ar⁺ ion beam) to argon ion-beam-assisted bromine etching to argon ion etching (no bromine) with an ion beam density of 40 μA/cm² and ion beam energy of 500 V were measured to be 11.5:23:1 and 16:125:1 at a substrate temperature of 200°C and 2:42:1 and 1:40:1 at a substrate temperature of 100°C for GaAs and InP, respectively. Such rate enhancements were found to be typical with these materials. Bromine ion-beam-assisted etching also appears to have an advantage over chlorine ion-beam-assisted etching in that high anisotropy can be achieved with bromine in both the GaAs and the InP materials systems at substrate temperatures as high as 200°C as comp.red to chlorine where the etching of GaAs is spontaneous and isotropic at temperatures above 150°C. © 1998 American Vacuum Society.

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Reasoning about Java classes: preliminary report 98

Reasoning about Java classes: preliminary report

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Proceedings of the 13th ACM SIGPLAN conference on Object-oriented programming, systems, languages, and applications

作者： Bart Jacobs Joachim van den Berg Marieke Huisman Martijn van Berkum U. Hensel H. Tews Dep. Comp. Sci. Univ. Nijmegen P.O. Box 9010 6500 GL Nijmegen The Netherlands Inst. Theor. Informatik TU Dresden D-01062 Dresden Germany

ISBN: (纸本)9781581130058

We present the first results of a project called LOOP, on formal methods for the object-oriented language Java. It aims at verification of program properties, with support of modern tools. We use our own front-end tool (which is still partly under construction) for translating Java classes into higher order logic, and a back-end theorem prover (namely PVS, developed at SRI) for reasoning. In several examples we demonstrate how non-trivial properties of Java programs and classes can be proven following this two-step approach.

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Simplication of symbolic-numerical interval expressions 98

Simplication of symbolic-numerical interval expressions

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Proceedings of the 1998 international symposium on Symbolic and algebraic comp.tation

作者： E. D. Popova C. P. Ullrich Inst. of Mathematics & Comp. Sci. Bulgarian Academy of Sciences Acad. G. Bonchev str. block 8 BG-1113 Sofia Bulgaria Institute for Informatics University of Basel Mittlere Str. 142 CH-4056 Basel Switzerland

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A Region-Based Representation of Images in MARS

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Journal of VLSI Signal Processing Systems for Signal, Image, and Video Technology 1998年第1-2期20卷 137-150页

作者： Servetto, Sergio D. Rui, Yong Ramchandran, Kannan Huang, Thomas S. Beckman Inst. Adv. Sci. and Technol. Univ. Illinois at Urbana-Champaign Urbana IL 61801 United States Universidad Nacional de La Plata Argentina Univ. Illinois at Urbana-Champaign United States Comp. Res. Adv. Applications Group IBM Argentina Argentina Image Formation and Processing Group Beckman Institute UIUC United States Department of Computer Science UNLP Argentina Dept. of Elec. and Comp. Engineering UIUC United States Multimedia Commun. Res. Department Bell Laboratories Murray Hill NJ United States Info. Sciences Research Department AT and T Labs. Florham Park NJ United States Department of Computer Science UIUC United States Southeast University China Tsinghua University China University of Illinois Urbana-Champaign IL United States Image Formation and Processing Group Beckman Inst. Advance Sci. Technol. UIUC United States Vis. Technol. Grp. of Microsoft Res. Redmond WA United States City College of New York United States Columbia University United States AT and T Bell Labs. United States Ctr. for Telecommunications Research Columbia University United States Elec. and Comp. Eng. Department United States Beckman Institute Coordinated Science Laboratory IL United States IEEE Signal Processing Society United States IEEE IMDSP Technical Committee United States IEEE Transactions on Image Proc. United States National Taiwan University Taipei Taiwan Massachusetts Inst. of Technology Cambridge MA United States Department of Electrical Engineering MIT United States School of Electrical Engineering United States Lab. for Info. and Signal Processing Purdue University United States Dept. of Elec. and Comp. Engineering United States Coordinated Science Laboratory United States Image Formation and Processing Group Beckman Inst. Adv. Sci. and Technol. United States MIT Lincoln Laboratory IBM Thomas J. Watson Research Center Rheinishes Landes Museum Bonn Germany Swiss Institutes of Technology Zurich Switzerland Swiss Institutes of Technology Lausanne S

We study the problem of representing images within a multimedia Database Management System (DBMS), in order to support fast retrieval operations without comp.omising storage efficiency. To achieve this goal, we propose new image coding techniques which combine a wavelet representation, embedded coding of the wavelet coefficients, and segmentation of image-domain regions in the wavelet domain. A bitstream is generated in which each image region is encoded independently of other regions, without having to explicitly store information describing the regions. Simulation results show that our proposed algorithms achieve coding performance which comp.res favorably, both perceptually and objectively, to that achieved using state-of-the-art image/video coding techniques while additionally providing region-based support.

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The zero of potential

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IEEE Engineering in Medicine and Biology Magazine 1998年第1期17卷 128-132+136页

作者： Geselowitz, David B. Bioengineering Program Pennsylvania State University University of Pennsylvania Philadelphia PA United States Department of Medicine M.I.T. Duke University Univ. of Oklahoma Hlth. Sci. Center University of New Mexico IEEE American College of Cardiology Amer. Inst. of Med. and Biol. Eng. Biomedical Engineering Society Intl. Soc. Comp. Electrocardiology Committe on Electrocardiography American Heart Association National Academy of Engineering Pennsylvania State University Bioengineering Program 232 Hallowell Building University Park PA 16802 United States

It is convenient to select a reference point for recording ECG potentials on the torso or EEG potentials on the scalp. The body is a bounded, insulated volume conductor. As such, it is meaningless to seek a point whose potential is at true zero. The choice of a particular reference, and hence the amplitude assigned to a contour, does not change in any way the biophysical information contained in the potential distribution. It does not in any way change the relation between source and potential, except for an additive constant of no physical significance. Standardization of a reference is useful for comp.ring, more directly, data from different laboratories. An agreed upon reference is necessary when a limited number of leads are used for diagnosis. In the case of the electrocardiogram, the generally agreed upon reference is the WCT. The issue of the zero of potential seems to arouse passions that may sometimes inhibit sci.ntific discourse.

关键词： Bioelectric phenomena Electric potential Heart Conductors Skin Electrodes Voltage Insulation Disk recording Conductivity

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