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A hamiltonian approach to the eikonal equation 2nd

2nd International Workshop on Energy Minimization Methods in computer Vision and Pattern Recognition, EMMCVPR 1999

作者： Siddiqi, Kaleem Tannenbaum, Allen Zucker, Steven W. School of Computer Science and Center for Intelligent Machines McGill University McGill University 3480 University Street MontréalPQH3A 2A7 Canada Department of Electrical and Computer Engineering University of Minnesota University of Minnesota 200 Union Street S. E MinneapolisMN55455 United States Department of Computer Science and Center for Computational Vision and Control Yale University Yale University New HavenCT06520-8285 United States

ISBN: (纸本)3540662944

The eikonal equation and variants of it are of significant interest for problems in computer vision and image processing. It is the basis for continuous versions of mathematical morphology, stereo, shapefrom-shading and for recent dynamic theories of shape. Its numerical simulation can be delicate, owing to the formation of singularities in the evolving front, and is typically based on level set methods introduced by Osher and Sethian. However, there are more classical approaches rooted in Hamiltonian physics, which have received little consideration in the computer vision literature. Here the front is interpreted as minimizing a particular action functional. In this context, we introduce a new algorithm for simulating the eikonal equation, which offers a number of computational advantages over the earlier methods. In particular, the locus of shocks is computed in a robust and efficient manner. We illustrate the approach with several numerical examples. © Springer-Verlag Berlin Heidelberg 1999.

关键词： Mathematical morphology

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Integrating information retrieval techniques with traditional DB methods in a web-based database browser 98

Integrating information retrieval techniques with traditiona...

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1998 ACM Symposium on Applied Computing, SAC 1998

作者： Sabin, Roberta Evans Yap, Tieng K. Computer Science Department Loyola College BaltimoreMD21210 United States Computational Bioscience and Engineering Laboratory National Institutes of Health BethesdaMD20817 United States

ISBN: (纸本)0897919696

A Web-based tool for retrieval of documents containing disparate types of data from a large collection is described. This tool uses a relational database system to implement information retrieval methodologies and allows naive users to query the database using freeform expressions instead of a formal query language such as SQL. The database relations contain both attributes whose values may be compared with relational operations and terms from free text portions of the documents which are stored along with measures of information content that allow the ranking of query results. This paper illustrates an application of this integrated tool to the retrieval of biological sequence information. © 1998 ACM.

关键词： Information retrieval

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Automated optimal design of two dimensional high speed missile inlets 36th

Automated optimal design of two dimensional high speed missi...

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36th AIAA Aerospace sciences Meeting and Exhibit, 1998

作者： Blaize, Michael Knight, Doyle Rasheed, Khaled Department of Mechanical and Aerospace Engineering United States Department of Computer Science Center for Computational Design United States Rutgers University The State University of New Jersey PO Box 909 PiscatawayNJ08855-0909 United States

A new methodology has been developed for automated optimal design of two dimensional high speed inlets. A semi-empirical flow solver and an improved Genetic Algorithm are linked within an automated loop. The purpose of this process is to maximize the total pressure recovery of the missile inlet: first of all, for one upstream flow condition, and secondly for an entire mission. This innovative design strategy allows great improvement of the original inlet design in a very short period of time. Successful results are presented from optimizations of inlets designed and tested at the Institute of Theoretical and Applied Mechanics (ITAM) in Novosibirsk, Russia. The significant improvements of the total pressure recovery, achieved by the Automated Optimization Loop, are verified using a full Navier- Stokes solver. © 1997, American Institute of Aeronautics and Astronautics, Inc.

关键词： Missiles

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Designing dynamic temporally sensitive fuzzy neural networks

Designing dynamic temporally sensitive fuzzy neural networks

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Conference of the North American Fuzzy Information Processing Society - NAFIPS

作者： M.H. Smith W. Pedrycz Department of Electrical Engineering and Computer Science University of California Berkeley CA USA Computational Intelligence Laboratory Department of Electrical and Computer Engineering University of Manitoba Winnipeg Canada

The concept of temporally sensitive fuzzy neural networks is introduced based on combining the basic ideas of logic-based neurocomputing with the concept of temporally sensitive connections of neural networks. This new class of neural networks helps address two main issues arising in time-dependent modeling environments. Firstly, these neural networks capture the underlying logical fabric of the problem and, secondly, they provide a useful insight into the temporal nature of the modeling environment. The authors show that the continuously changeable temporal environment gives rise to a logical transformation of the introduced model. This transformation is implemented by triggering from its original AND-like nature to an OR-like version, with this triggering regarded as a function of time. This paper discusses fuzzy decision-making in detail, particularly real estate problem solving.

关键词： Fuzzy neural networks Neural networks Decision making Fuzzy logic Fuzzy systems Fuzzy sets computer science Robot sensing systems Fabrics Problem-solving

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Optimal parameter updating for optical diffusion imaging

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IEEE International Conference on Image Processing

作者： J.C. Ye K.J. Webb R.P. Millane T.J. Downar Electrical and Computer Engineering Department Purdue University West Lafayette IN USA Computational Science and Engineering Purdue University West Lafayette IN USA

ISBN: (纸本)0818688211

Because optical diffusion imaging is a highly nonlinear inverse problem, iterative inversion algorithms based on the Born approximation have usually been employed as reconstruction technique, but convergence is slow, especially for high contrast parameter distributions. We show here that the slow convergence of the conventional algorithms is due to the linear integral operator derived by the Born approximation not being the optimal Frechet derivative. We derive the optimal Frechet derivative operator with respect to the spatially varying absorption and scattering coefficients in integral form, and then develop a new iterative inversion algorithm.

关键词： Optical imaging Optical scattering Iterative algorithms Nonlinear optics Approximation algorithms Approximation methods Convergence Inverse problems Image reconstruction Absorption

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3-D hypersonic inlet optimization using a genetic algorithm 34th

3-D hypersonic inlet optimization using a genetic algorithm

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34th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 1998

作者： Chernyavsky, B. Stepanov, V. Rasheed, K. Blaize, M. Knight, D. Gas Dynamics Department of Central Institute of Aviation Motors Dept. Mechanical and Aerospace Engineering Rutgers University Moscow Central Institute of Aviation Motors Russia Rutgers University Dept. of Computer Science and Center for Computational Design New Brunswick Rutgers University NJ United States Dept. of Mechanical and Aerospace Engineering Center for Computational Design New Brunswick Rutgers University NJ United States

A numerical code has been developed for automatic aerodynamic optimization of supersonic 3- D inlet design with a high value of total pressure recovery coefficient with the aid of an improved Genetic Algorithm (GADO). The code combines GA and simple 1-D flow solver to form an optimization loop. The code is intended for optimization of inlet geometry, based on one optimization criteria and set of variable optimizing parameters. The code has been tested on a model problem considering optimization of Trexler-type 3-D inlet for Mach number range from 3 to 8. The optimizing parameters have been wedge panel angles and wedge leading edge sweep angle, determining inlet geometry. Total pressure recovery was used as an optimization criteria. The dependencies of wedge panel angles, wedge leading edge sweep angle and Mach number on total pressure recovery coefficient have been studied. Optimum inlet configurations have been obtained and compared for different number of wedge panels and Mach numbers in a range from 3 to 8. The influence of the turbulent boundary layer separation restriction on the integral inlet characteristics has been studied and obtained results have been compared for cases both with and without account for flow separation criteria. Calculations have shown, that account for turbulent boundary layer separation with the use of Gedd criterion significantly decrease expected inlet performance. © 1998 by Boris Chernyavsky, Vladimir Stepanov, Khaled Rasheed, Michael Blaize and Doyle Knight.

关键词： Mach number

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Editorial

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International Journal of Pattern Recognition and Artificial Intelligence 1998年第4期12卷 379-380页

作者： Jukka Heikkonen Rainer Herpers Laboratory of Computational Engineering Helsinki University of Technology P.O. Box 9400 FIN-02150 TKK Finland University of Toronto Department of Computer Science AI Lab Computer Vision Group D. L. Pratt Building Room 265C 6 King's College Road Toronto Ontario M5S 3H5 Canada

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The seasonal to interannual Earth science Information Partner: a distributed data and information broker

The seasonal to interannual Earth Science Information Partne...

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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： M. Kafatos D. Ziskin P. Chan Long Chiu B. Doty J. Kinter T. El-Ghazawi Zuotao Li X.S. Wang Ruixin Yang C. Willmott Center for Earth Observing and Space Research CEOSR Computational Science and Informatics CSI George Mason University Fairfax VA USA Distributed Active Archive Center NASA Goddard Space Flight Center Greenbelt MD Center for Ocean-Land-Atmosphere Studies MD Division of Electrical and Computer Science and Engineering Florida Institute of Technology Melbourne FL CEOSR George Mason University Fairfax VA Department of Geography University of Delaware Newark DE

A consortium of three main sites consisting of the Center for Earth Observing and Space Research (CEOSR) at George Mason University (GMU), the Center for Ocean-Land-Atmosphere Studies (COLA) and the NASA Goddard Space Flight Center Distributed Active Archive Center (GDAAC) has been formed. This consortium was recently funded by NASA's Earth science Information Partner program to provide data and information products serving the needs of seasonal to interannual (S-I) scientists and other related science communities. Specifically, CEOSR will provide information technology and a distributed system architecture as wall as specific data products to be accessed by the scientific communities, COLA will provide scientific direction and a widely-used tool in the S-I research communities and GDAAC data management and archiving. Along with several other contributors, our consortium will create an interdisciplinary source of data for S-I researchers to expand the usage and usefulness of NASA data and serve as broker on behalf of the S-I researchers by providing them enhanced access to NASA's data. The consortium under guidance by an advisory board of experts will select the most appropriate data from the DAAC, NOAA, COLA and the University of Delaware for S-I research applications. Metadata and summary statistics will be extracted and stored in databases at distributed nodes, while the data will be stored on an advanced array of disks. There will be a JAVA-based WWW user interface featuring three advances: (1) content-based searching of the summary metadata (2) exploratory analysis of on-line data and (3) phenomenon-based searching. The consortium will be responsive to the changing needs of its science users as well as in tune with significant information technology advances.

关键词： Geoscience NASA Information technology Earth Space technology Technology management Statistical distributions Data mining Distributed databases Spatial databases

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computer simulations of stimulus dependent state switching in basic circuits of bursting neurons

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Physical Review E 1998年第5期58卷 6418-6418页

作者： Mikhail Rabinovich Ramón Huerta Maxim Bazhenov Alexander K. Kozlov Henry D. I. Abarbanel Institute for Nonlinear Science University of California San Diego La Jolla California 92093-0402 Department of Computer Engineering Universidad Autónoma de Madrid 29049 Madrid Spain Howard Hughes Medical Institute The Salk Institute Computational Neurobiology Laboratory La Jolla California 92037 Institute of Applied Physics Russian Academy of Sciences 46 Ulyanov Street Nizhny Novgorod 603600 Russia Department of Physics and Marine Physical Laboratory Scripps Institution of Oceanography University of California San Diego Mail Code 0402 La Jolla California 92093-0402

We investigate the ability of oscillating neural circuits to switch between different states of oscillation in two basic neural circuits. We model two quite distinct small neural circuits. The first circuit is based on invertebrate central pattern generator (CPG) studies [A. I. Selverston and M. Moulins, The Crustacean Stomatogastric System (Springer-Verlag, Berlin, 1987)] and is composed of two neurons coupled via both gap junction and inhibitory synapses. The second consists of coupled pairs of interconnected thalamocortical relay and thalamic reticular neurons with both inhibitory and excitatory synaptic coupling. The latter is an elementary unit of the thalamic networks passing sensory information to the cerebral cortex [M. Steriade, D. A. McCormick, and T. J. Sejnowski, science 262, 679 (1993)]. Both circuits have contradictory coupling between symmetric parts. The thalamocortical model has excitatory and inhibitory connections and the CPG has reciprocal inhibitory and electrical coupling. We describe the dynamics of the individual neurons in these circuits by conductance based ordinary differential equations of Hodgkin-Huxley type [J. Physiol. (London) 117, 500 (1952)]. Both model circuits exhibit bistability and hysteresis in a wide region of coupling strengths. The two main modes of behavior are in-phase and out-of-phase oscillations of the symmetric parts of the network. We investigate the response of these circuits, while they are operating in bistable regimes, to externally imposed excitatory spike trains with varying interspike timing and small amplitude pulses. These are meant to represent spike trains received by the basic circuits from sensory neurons. Circuits operating in a bistable region are sensitive to the frequency of these excitatory inputs. Frequency variations lead to changes from in-phase to out-of-phase coordination or vice versa. The signaling information contained in a spike train driving the network can place the circuit into one or ano

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A poly-algorithm for parallel dense matrix multiplication on two-dimensional process grid topologies

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Concurrency and Computation: Practice and Experience 1998年第5期9卷

作者： J. Li A. Skjellum R. D. Falgout Department of Computer Science & NSF Engineering Research Center Mississippi State University Mississippi State MS 39762 USA Center for Computational Sciences and Engineering L-316 Lawrence Livermore National Laboratory Livermore CA 94550 USA

In this paper, we present several new and generalized parallel dense matrix multiplication algorithms of the form C = α AB + β C on two-dimensional process grid topologies. These algorithms can deal with rectangular matrices distributed on rectangular grids. We classify these algorithms coherently into three categories according to the communication primitives used and thus we offer a taxonomy for this family of related algorithms. All these algorithms are represented in the data distribution independent approach and thus do not require a specific data distribution for correctness. The algorithmic compatibility condition result shown here ensures the correctness of the matrix multiplication. We define and extend the data distribution functions and introduce permutation compatibility and algorithmic compatibility . We also discuss a permutation compatible data distribution ( modified virtual 2D data distribution ). We conclude that no single algorithm always achieves the best performance on different matrix and grid shapes. A practical approach to resolve this dilemma is to use poly-algorithms. We analyze the characteristics of each of these matrix multiplication algorithms and provide initial heuristics for using the poly-algorithm. All these matrix multiplication algorithms have been tested on the IBM SP2 system. The experimental results are presented in order to demonstrate their relative performance characteristics, motivating the combined value of the taxonomy and new algorithms introduced here. © 1997 by John Wiley & Sons, Ltd.

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