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IEEE International Conference on Fuzzy Systems (FUZZ-IEEE)

作者： Guoqing Chen E.E. Kerre MIS Division School of Economics & Management Tsinghua University Beijing China Department of Applied Mathematics & Computer Science University of Gent IMEC Ghent Belgium

Entity relational (ER) and enhanced ER (EER) models play an important role in conceptual data modeling. This paper presents fuzzy extensions to several major ER/EER concepts so that uncertainty and imprecision in data and semantics can be represented and dealt with at a conceptual level. First, fuzzy extensions to basic ER/EER concepts such as superclass/subclass, generalization/specialization, and shared subclass/category are discussed. Next, the attribute inheritance is investigated in a fuzzy context, including multiple inheritance, selective inheritance, and the inheritance for derived attributes. Finally, certain constraints on relationships are explored in terms of the inheritance constraint, the participation constraint, and the cardinality constraint.

关键词： Erbium Object oriented modeling Fuzzy sets Object oriented databases mathematics computer science Uncertainty Information systems Information analysis Fuzzy set theory

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Autonomous garbage collection: resolving memory leaks in long running network applications

Autonomous garbage collection: resolving memory leaks in lon...

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International Conference on computer Communications and Networks (ICCCN)

作者： B. Willard O. Frieder Electronics and Systems Integration Division Northrop Grumman Corporation Melbourne FL USA Department of Computer Science & Applied Mathematics Illinois Institute of Technology Chicago IL USA

ISBN: (纸本)0818690143

Garbage collection is especially useful for long running server applications in network environments since sustained memory leaks continuously degrade performance and eventually result in application failure. We demonstrate the benefits of a garbage collection technique that effectively mitigates performance degeneration due to memory leaks in applications when source code or object code are not available. Our technique is an extension of the garbage collection method known as conservative garbage collection. We refer to this as autonomous garbage collection. Our prototype demonstrates that this garbage collection technique is indeed feasible. Furthermore, our experimental results show that this technique is more general and easier to use than many of the previous garbage collection proposals targeted at resolving memory leaks in non-cooperative server applications.

关键词： Intelligent networks Random access memory Network servers programming profession Memory management Application software Read-write memory Telecommunication network reliability Degradation Prototypes

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A faster Galerkin boundary integral algorithm

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International Journal for Numerical Methods in Biomedical Engineering 1998年第12期14卷

作者： L. J. Gray B. E. Griffith Computer Science and Mathematics Division Oak Ridge National Laboratory Oak Ridge TN 37831-6367 U.S.A. Department of Computational and Applied Mathematics Rice University Houston TX 77005-1892 U.S.A.

The symmetry present in Green's functions is exploited to significantly reduce the matrix assembly time for a Galerkin boundary integral analysis. A relatively simple modification of the standard Galerkin implementation for computing the non-singular integrals yields a 20–30 per cent decrease in computation time. This faster Galerkin method is developed for both singular and hypersingular equations, and applied to symmetric-Galerkin implementations in two dimensions for the Laplace equation and for orthotropic elasticity. In three dimensions, the modified algorithm has been implemented for the singular equation for the Laplace and elastodynamics equations. Comparison timing results for standard and modified algorithms are presented. Copyright © 1998 John Wiley & Sons, Ltd.

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Analytic streamline calculations on linear tetrahedra 13th

Analytic streamline calculations on linear tetrahedra

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13th Computational Fluid Dynamics Conference, 1997

作者： Diachin, Darin P. Herzog, James A. Mathematics and Computer Science Division Argonne National Laboratory ArgonneIL60439 United States ANL Northwestern University in Theoretical and Applied Mechanics United States ANL Stanford University in Scientific Computing and Computational Mathematics United States

Analytic solutions for streamlines within tetrahedra are used to define operators that accurately and efficiently compute streamlines. The method presented here is based on linear interpolation, and therefore produces exact results for linear velocity fields. In addition, the method requires less computation than the forward Euler numerical method. Results are presented that compare accuracy measurements of the method with forward Euler and fourth-order Runge-Kutta applied to both a linear and a nonlinear velocity field. © 1997 American Institute of Aeronautics and Astronautics, Inc.

关键词： Numerical methods

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Developing a prototype concurrent design tool for composite topside structures

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NAVAL ENGINEERS JOURNAL 1997年第3期109卷 279-290页

作者： Dirlik, S Hambric, S Azarm, S Marquardt, M Hellman, A Bartlett, S Castelli, V Steve Dirlik:began his career at the Naval Surface Warfare Center Carderock Division in 1981 as an aerospace engineer co-op student. He completed his bachelor of science degree in aeropace and ocean engineering from Virginia Polytechnic Institute and State University in 1985 and his master of science degree in aerospace engineering from the University of Maryland in 1990. Mr. Dirlik recently completed a master of science program in applied physics at The Johns Hopins University and currently works in the Radar Cross Section and Target Physics Branch of the Signatures Directorate at the Naval Surface Warfare Center Corderoke Division. He has worked on Navy low observable programs since 1990. Stephen Hambric:is a research associate at the Applied Research Laboratory at The Pennsylvania State University. He received his B. S. and M.S. degree in mechanical engineering from Virginia Polytechnic Institute and State University and his D. Sc. in mechnical engineering from the George Washington University. He has worked on several computer aided multidiscikplinary design and optimization projects over the years including an automated propeller design system and a structural acoustic optimization capability. Dr. Shpour Azarm:is currently working as an associate professor with the Design and Manufacturing Group of the Department of Mechanical Engineering at the University of maryland at College Park. Dr Azarm's expertise is in the areas of optimization-based designed and concurrent design and optimization of multidisciplinary systems. He was a consultant at Black & Decker Corporation (summer 1996) and worked as a Navy senior summer faculty fellow (summer 1995) and a NASA summer faculty fellow (summer 1994). He was a visiting scientist at NASA Langley Research Center for Multidisciplinary Analysis and Applied Structural Optimzatiom at the University of Siegen in Germany (spring 1992) and the Design Institute of the Technical University of Denmark (summer 1990). Dr Azarm was an associate technical editor of the ASME Jour

A prototype concurrent engineering tool has been developed for the preliminary design of composite topside structures for modern navy warships. This tool, named GELS for the Concurrent Engineering of Layered Structures, provides designers with an immediate assessment of the impacts of their decisions on several disciplines which are important to the performance of a modern naval topside structure, including electromagnetic interference effects (EMI), radar cross section (RCS), structural integrity, cost, and weight. Preliminary analysis modules in each of these disciplines are integrated to operate from a common set of design variables and a common materials database. Performance in each discipline and an overall fitness function for the concept are then evaluated. A graphical user interface (GUI) is used to define requirements and to display the results from the technical analysis modules. Optimization techniques, including feasible sequential quadratic programming (FSQP) and exhaustive search are used to modify the design variables to satisfy all requirements simultaneously. The development of this tool, the technical modules, and their integration are discussed noting the decisions and compromises required to develop and integrate the modules into a prototype conceptual design tool.

关键词： Warships

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Operational systems, logistics engineering and technology insertion

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NAVAL ENGINEERS JOURNAL 1997年第3期109卷 205-220页

作者： Grubb, MJ Skolnick, A Michael J. Grubb:has perfomzed naval engineering at the Crane Division Naval Surface Warfare Center (NSWC) for more than twenty-five years. He currently the program manager for the Sustainable Hardware and Affordable Readiness Practice Program (SHARP). is a Navy-wide logistics research and development prgram aimed at the successful transiton of proved technologies inot the fleet. SHARP focuses on reducing acquisition performance capability reliability maintainability and readiness of these systems. Mr. Grubb has served as a department director for the past eleven years. His most recent assignment was as director of the Tactical Computer Resources and Test Equipment Department. This organization provided acquisition and in-service engineering support of the Navy's tectical embedded computers priphirals displays and mass memory storage devices. The organization also provided a complete range of product engineering and metrology engineerig services for SSP NevSeaSysCom and the Trident Program. Prior to this appointment Mr. Grubb was deptuy director psysical security programs department and site responsible for program management and system integration of ashore integrated security systems. Mr. Grubb holds a B.S. degree in industrial engineering from Iowa State Universtiy an M.S. degree in industrial engineering from Purdue University and has copleted the course work (Dec.'96 for a master's degree in public and environment affairs at Indiana University-Purdue Univeristy Indianapolis. Dr. Alfred Skolnick operates System Science Consultants (SSC) specilizing in strategic planning technical program definiton technology assessment and engineering analyses on selected matters of national interest. He has taught physics mathematics and management sciences at University of Virginia and Marymount University and is currently adjunct professor of mathematics at Northern Virginia Community College. Form 1985 to 1989 he was president of the American Society of Noval Engineers. Dr. Skolnick served at Applied Physic

In an era of fiscal austerity, downsizing and unforgiving pressure upon human and economic capital, it is an Augean task to identify resources for fresh and creative work. The realities of the day and the practical demands of more immediate fleet needs can often dictate higher priorities. Yet, the Navy must avoid eating its seed corn. Exercising both technical insight and management foresight, the fleet, the R&D community, the Office of the Chief of Naval Operations (OpNav) and the product engineering expertise of the Naval Surface Warfare Center (NSWC) are joined and underway with integrated efforts to marry new, fully demonstrated technologies and operational urgencies. Defense funding today cannot sponsor all work that can be mission-justified over the long term because budgets are insufficient to support product maturation within the classical development cycle. However, by rigorous technical filtering and astute engineering of both marketplace capabilities and currently available components, it is possible in a few select cases to compress and, in effect, integrate advanced development (6.3), engineering development (6.4), weapon procurement (WPN), ship construction (SCN), operation and maintenance (O&M,N) budgetary categories when fleet criticalities and technology opportunities can happily meet. In short, 6.3 funds can be applied directly to ''ripe gateways'' so modern technology is inserted into existing troubled or aging systems, sidestepping the lengthy, traditional development cycle and accelerating practical payoffs to recurrent fleet problems. To produce such constructive results has required a remarkable convergence of sponsor prescience and engineering workforce excellence. The paper describes, extensively, the philosophy of approach, transition strategy, polling of fleet needs, technology assessment, and management team requirements. The process for culling and selecting specific candidate tasks for SHARP sponsorship (matching operational need with t

关键词： Naval vessels

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SPINET: a parallel computing approach to spine simulations

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Scientific programming 1996年第1期5卷 15-15页

作者： Kropf, Peter G. Lederer, Edgar F.A. Steffen, Thomas Guggisberg, Karl Schneider, Jean-Guy Schwab, Peter Department of Computer Science Laval University Quebec City Canada Institute of Computer Science University of Basel Switzerland Orthopaedic Research Laboratory Division of Orthopaedic Surgery McGill University Montreal Canada Institute of Computer Science and Applied Mathematics University of Berne Switzerland

Research in scientitic programming enables us to realize more and more complex applications, and on the other hand, application-driven demands on computing methods and power are continuously growing. Therefore, interdisciplinary approaches become more widely used. The interdisciplinary SPINET project presented in this article applies modern scientific computing tools to biomechanical simulations: parallel computing and symbolic and modern functional programming. The target application is the human spine. Simulations of the spine help us to investigate and better understand the mechanisms of back pain and spinal injury. Two approaches have been used: the first uses the finite element method for high-performance simulations of static biomechanical models, and the second generates a simulation developmenttool for experimenting with different dynamic models. A finite element program for static analysis has been parallelized for the MUSIC machine. To solve the sparse system of linear equations, a conjugate gradient solver (iterative method) and a frontal solver (direct method) have been implemented. The preprocessor required for the frontal solver is written in the modern functional programming language SML, the solver itself in C, thus exploiting the characteristic advantages of both functional and imperative programming. The speedup analysis of both solvers show very satisfactory results for this irregular problem. A mixed symbolic-numeric environment for rigid body system simulations is presented. It automatically generates C code from a problem specification expressed by the Lagrange formalism using Maple.

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An extended Boyce-Codd normal form in fuzzy relational databases

An extended Boyce-Codd normal form in fuzzy relational datab...

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IEEE International Conference on Fuzzy Systems (FUZZ-IEEE)

作者： Guoqing Chen E.E. Kerre J. Vandenbulcke MIS Division School of Economics & Management Tsinghua University Beijing China Department of Applied Mathematics & Computer Science University of Ghent Ghent Belgium Informatics Division Department of Applied Economics Catholic University슠of슠Leuven Leuven Belgium

If the relation schemes of any fuzzy database are not properly designed certain anomaly problems may occur when the fuzzy database is updated or maintained. This is because some undesired relationships exist among attributes. Based on the notions of fuzzy functional dependency (FFD) and /spl theta/-keys, the Boyce-Codd normal form is extended to cope with the anomaly problems caused by partial and transitive FFDs of /spl theta/-prime on some /spl theta/-keys, thus resulting in /spl theta/-fuzzy Boyce-Codd normal form (/spl theta/-FBCNF). Furthermore, the relationship between /spl theta/-FBCNF and other existing fuzzy normal forms is analyzed, showing that /spl theta/-FBCNF reflects the strongest restriction for attributes. Finally an algorithm is provided that can decompose, in a lossless-join manner, any scheme into a number of /spl theta/-FBCNF schemes.

关键词： Relational databases Testing

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Models of phosphate kinetics in dialysis patients

Models of phosphate kinetics in dialysis patients

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Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

作者： A. Ruggeri S. Giove M. Nordio Department of Electronics and Informatics University of Padova Podova Italy Department of Applied Mathematics and Computer Science University of Venice Venice Italy Division of Nephrology Venice Hospital Venice Italy

During the dialytic treatment, plasma phosphate (Pi) has a very specific time course. It reaches a nadir value approximately 90 minutes after the beginning of the treatment and then, despite the ongoing removal, it exhibits either a constant steady state or a slow rebound. In order to quantitatively describe the kinetics, the authors have proposed a set of different compartmental control models, which have been compared by using criteria based on mathematical indices and physiological considerations. The resulting best model has two compartments, which represent plasma and intra-cellular fluids (IF) respectively, In order to explain the Pi time course, it postulates two fluxes of Pi into plasma: one from IF, proportional to the decrease of plasma Pi from its pre-dialysis value, and one from an endogenous source (probably the bone surface), again proportional to the decrease of plasma Pi but also inversely proportional to Pi concentration in IF. This model was able to achieve a very good fit of all the experimental data (7 subjects) and good precision of parameter estimates. Moreover, it proved capable of correctly predicting also the qualitative time course of Pi in the post dialysis period.

关键词： Kinetic theory Mathematical model Plasma sources Steady-state Medical treatment Informatics mathematics computer science Hospitals Nuclear and plasma sciences

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On Measures of Non-Integrability of Pfaffian Systems

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IFAC Proceedings Volumes 1996年第1期29卷 2132-2137页

作者： Andrzej Banaszuk John Hauser Willem M. Sluis Richard M. Murray Department of Mathematics University of California Davis CA 95616-8633 Department of Electrical and Computer Engineering University of Colorado Boulder CO 80309-0425 Control and Dynamical Systems 104-44 California Institute of Technology Pasadena CA 91125 Division of Engineering and Applied Science California Institute of Technology Pasadena CA 91125

Many problems in nonlinear control theory (like, for instance, feedback linearization problem) leed to examination of integrability of a Pfaffian system. In a generic case a Pfaffian system is not integrable. Therefore, how to approximate non-integrable Pfafian systems by integrable ones and how this approximation can applied in practice appears to be a natural and important problem. In the present paper we establish some measures of non-integrability of Pfaffian system of arbitrary dimension and discuss their relation to approximations of non-integrable Pfaffian systems by integrable ones. Our work is motivated by expected applications to approximate feedback linearization of multi-input nonlinear systems.

关键词： Nonlinear systems differential geometry differential forms Pfaffian systems feedback linearization

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