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Reduction of Large-Scale Groundwater Flow Models Via the Galerkin Projection

IFAC Proceedings Volumes 2003年第16期36卷 1381-1386页

作者： P.T.M. Vermeulen A.W. Heemink C.B.M Te Stroet Department of Applied Mathematical Analysis Faculty of Electrical Engineering Mathematics and Computer Science Delft University of Technology P.O. Box 5031 2600 GA Delft the Netherlands Netherlands Institute of Applied Geoscience TNO National Geological Survey P.O. Box 80015 3508 TA Utrecht the Netherlands

In this paper we describe a reduced model structure that describes the hydraulic head h for ground water flow models as a linear combination of a set of spatial patterns P with time-varying coefficients r. We discuss a data-driven technique to extract patterns P (EOFs) that span a subspace of model results that captures most of the relevant information of the original model. We make use of the patterns to obtain a reduced dynamic model for the time-varying coeffecients via a Galerkin Projection. This technique substitutes h within the PDE for groundwater now by the reduced model structure P T r. We acquire a dynamic reduced model for dr/dt by multiplying the outcome with P T . The vector dimension of r is often small compared to the original dimension of h, and a model which operates within a lower dimension requires less computational time. The method has heen evaluated for a realistic case, whereby we achieved a maximal reduction in computational time of ≈ 80. The reduced model has a promising prospect as its efficiency increases whenever the number of grid cells increases and the parameterization of the original model grows in complexity.

关键词： Groundwater Empirical Orthogonal Functions (EOFs) Large-scale Linear Model reduction Numerical methods

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On extensibilities of interconnection networks

On extensibilities of interconnection networks

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IEEE Pacific Rim Conference on Communications, computers and Signal Processing

作者： Jywe-Fei Fang Yu-Chin Liu Chao-Chin Wu Hsun-Wen Chang Department of Computer Science and Information Engineering Saint John''s and Saint Mary''s Institute of Technology Taiwan Department of Information Management Tung Nan Institute of Technology Taiwan Department of Computer Science and Information Engineering National Changhua University of Education Taiwan Department of Applied Mathematics Tatung University Taipei Taiwan

ISBN: (纸本)0780379780

Researchers have used number of nodes to measure the extensibility of a topology. However, this metric is not very evident. In this paper, we introduce a specific metric called extensible density to measure the extensibilities of interconnection networks. Some topologies have high degree of extensibilities, but efficient parallel algorithms can apply only on a special subclass of these topologies. Furthermore, we extend the concept of density to measure the applicable extent of parallel algorithms.

关键词： Multiprocessor interconnection networks Network topology Density measurement Parallel algorithms Tree graphs computer science Educational technology Hardware Costs Fault tolerance

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Geohydrological Application of a Nonlinear Physically Based Time Series Model

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IFAC Proceedings Volumes 2003年第16期36卷 1933-1938页

作者： W.L. Berendrecht A.W. Heemink F.C. van Geer J.C. Gehrels Department of Applied Mathematical Analysis Faculty of Electrical Engineering Mathematics and Computer Science Delft University of Technology P. O. Box 5031 2600 GA Delft the Netherlands Netherlands Institute of Applied Geoscience TNO National Geological Survey P.O. Box 80015 3508 TA Utrecht the Netherlands Department of Watermanagement Faculty of Civil Engineering and Geosciences Delft University of Technology P.O. Box 5048 2600 GA Delft the Netherlands

This paper presents a physically based time series model that relates groundwater level fluctuations to precipitation and evapotranspiration. The model is based on the nonlinear relation between the degree of water saturation of the subsoil and the groundwater recharge. The model is written in state-space form, while the extended Kalman filter is used to estimate the state equation. An example application shows that the model performs very well and that the addition of physical knowledge is a valuable extension to standard linear transfer function-noise models.

关键词： Extended Kalman filters Maximum likelihood estimators Nonlinear systems Physical models State-space models Time series analysis Transfer functions

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Erratum: Artistic Surface Rendering Using Layout of Text

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computer Graphics Forum 2003年第4期21卷

作者： Tatiana Surazhsky Gershon Elber Applied Mathematics Department Faculty of Computer Science Technion Israel Institute of Technology Haifa 32000 Israel

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MODIFIED PARALLEL ROSENBROCK METHODS FOR STIFF DIFFERENTIAL EQUATIONS

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Journal of Computational mathematics 2002年第1期20卷 23-34页

作者： Xue-nian Cao Shou-fu Li De-gui Liu Institute for Computational and Applied Mathematics Xiangtan UniversityXiangtan 411105China Beijing Institute of Computer Application and Simulation Technology Beijing 100854China

Presents a class of modified parallel Rosenbrock methods (MPROW) which possesses more free parameters to improve further the various properties of the methods and will be similarly written as MPROW. Information on par... 详细信息

关键词： numerical analysis stiff ordinary differential equations Rosenbrock methods parallel algorithms

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Human systems integration and advanced technology in engineering department workload and manpower reduction

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NAVAL ENGINEERS JOURNAL 2003年第1期115卷 57-65页

作者： Lively, KA Seman, AJ Kirkpatrick, M KENNETH A. LIVELY graduated from the University of Colorado with a BS in applied mathematics and an MS in mathematics in 1976 and from the Massachusetts Institute of Technology with an MS in electrical engineering and the degree ocean engineer in naval architecture and marine engineering in 1984. He retired from the U.S. Navy in 1989 after 23 years of service. Assignments included electrical officer on the USS Constellation (CV 64) project engineer for the DDG 51 machinery control system (NAVSEA) and DDG 51 Technical Director (NAVSEA). He was vice president of the PDI Division of Bird-Johnson Company from July 1989 to November 1998 where he managed various gas turbine and machinery controls related development projects. He joined Anteon Corporation's Systems Engineering Group as senior controls engineer in December 1998 where he provided technical support to the integrated power systems program (NAVSEA PMS 510) and managed the Office of Naval Research Afloat Laboratory. DR. MARK KIRKPATRICK is currently an independent consultant in human factors and work-load/manning analysis and modeling. He holds a Ph.D. degree in experimental psychology from The Ohio State University and has 34 years of experience in applied human factors. From 1982 through 2000 Dr. Kirkpatrick served as the senior vice president of Carlow International. Prior to joining Carlow in 1982 Dr. Kirkpatrick served as a member of the technical staff at North American Rockwell's Missiles Division and as a project director and vice president for Essex Corporation. His areas of expertise include workload simulation task analysis operator-in-the-loop simulation human performance experimentation statistical analysis and human factors T&E. He has directed and/or participated in human factors projects for the U.S. Navy U.S. Army NASA Department of Transportation the U.S. Nuclear Regulatory Commission and private industry. ANTHONY J. SEMAN III is the technical manager for the reduced ship's crew by virtual presence (RSVP) advanced technology d

Aboard current ships, such as the DDG 51, engineering control and damage control activities are manpower intensive. It is anticipated that, for future combatants, the workload demand arising from operation of systems under conditions of normal steaming and during casualty response will need to be markedly reduced via automated monitoring, autonomous control, and other technology initiatives. Current DDG 51 class ships can be considered as a manpower baseline and under Condition III typical engineering control involves seven to eight watchstanders at manned stations in the Central Control Station, the engine rooms and other machinery spaces. In contrast to this manning level, initiatives such as DD 21 and the integrated engineering plant (IEP) envision a partnership between the operator and the automation system, with more and more of the operator's functions being shifted to the automation system as manning levels decrease. This paper describes some human systems integration studies of workload demand reduction and, consequently, manning reduction that can be achieved due to application of several advanced technology concepts. Advanced system concept studies in relation to workload demand are described and reviewed including. Piecemeal applications of diverse automation and remote control technology concepts to selected high driver tasks in current DDG 51 activities. Development of the reduced ship's crew by virtual presence system that will provide automated monitoring and display to operators of machinery health, compartment conditions, and personnel health. The IEP envisions the machinery control system as a provider of resources that are used by various consumers around the ship. Resource needs and consumer priorities are at all times dependent upon the ship's current mission and the availability of equipment pawnbrokers.

关键词： Naval warfare

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Metamorphosis of planar parametric curves via curvature interpolation

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International Journal of Shape Modeling 2002年第2期8卷 201-216页

作者： Surazhsky, Tatiana Elber, Gershon Ctr. Graphics Geometric Computing Applied Mathematics Dept. Technion Israel Institute of Technology Haifa 32000 Israel Ctr. Graphics Geometric Computing Faculty of Computer Science Technion Israel Institute of Technology Haifa 32000 Israel

This work considers the problem of metamorphosis interpolation between two freeform planar curves. Given two planar parametric curves, the curvature signature of the two curves is linearly blended, yielding a gradual change that is not only smooth but also employs intrinsic curvature shape properties, and hence is highly appealing. In order to be able to employ this curvature blending, we present a constructive scheme to derive curvature signatures of parameter curves. Additionally, we propose a scheme to reconstruct a curve from its curvature signature.

关键词： Computational geometry

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Estimation of clock offset from one-way delay measurement on asymmetric paths

Estimation of clock offset from one-way delay measurement on...

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Symposium on Applications and the Internet (SAINT) Workshops

作者： Tsuru, M Takine, T Oie, Y Telecommun. Advancement Organ. Japan Dept. of Applied Mathematics and Physics Graduate School of Informatics Kyoto University Japan Dept. of Computer Science and Electronics Kyushu Institute of Technology Japan

ISBN: (纸本)0769514502;0769514510

As the Internet is shifting towards a reliable QoS-aware network, accurately synchronized clocks distributed in the Internet become more significant. Network Time Protocol (NTP) is broadly deployed in the Internet for clock synchronization among distributed hosts, but it is weak in asymetric paths, i.e., it cannot accurately estimate the clock offset between two hosts when the forward and backward paths between them have different one-way delays. In this paper, we focus on estimating the offset and the skew of a clock from one-way delay measurement between two hosts, and propose an idea for improvement of such estimations, which reduces estimation errors in case that the forward and backward paths have different bandwidths that is one of main factors of the asymmetric delays.

关键词： Application software Bandwidth Clocks Delay estimation Estimation error Internet IP networks Protocols Synchronization Web server

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Inferring traffic flow characteristics from aggregated-flow measurement

Inferring traffic flow characteristics from aggregated-flow ...

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Symposium on Applications and the Internet (SAINT 2002)

作者： Tsuru, M Takine, T Oie, Y GENESIS Project TAO (Telecommunications Advancement Organization) Japan Dept. of Applied Mathematics and Physics Graduate School of Informatics Kyoto University Japan Dept. of Computer Science and Electronics Kyushu Institute of Technology Japan

ISBN: (纸本)0769514472

In the Internet, a statistical perspective of global traffic flows has been considered as an important key to network management. Nonetheless, it is expensive or sometime difficult to measure statistics of each flow separately. Therefore, it is of practical importance to infer unobservable statistical characteristics of individual flows front characteristics of the aggregated-flows that are easily measured at some links (router interfaces) in the network. In this paper, we propose a new approach to such inference problems, and provide some examples of inferring unobservable arrival rates of packets on each flow front measurement of the aggregated-flows. Our method is applicable to cases not covered by the existing methods for the OD traffic matrix inference. We also show simulation results, which indicate potential of our approach.

关键词： computer network management computer science Fluid flow measurement Informatics IP networks mathematics Physics Routing Telecommunication traffic Traffic control

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Fault-tolerant routing on the star graph with safety vectors

Fault-tolerant routing on the star graph with safety vectors

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International Symposium on Parallel Architectures, Algorithms and Networks, I-SPAN 2002

作者： Yeh, Sheng-I Yang, Chang-Biau Chen, Hon-Chan Department of Applied Mathematics National Sun Yat-sen University Taiwan Department of Computer Science and Engineering National Sun Yat-sen University Kaohsiung80424 Taiwan Department of Shipping Transportation and Management National Kaohsiung Institute of Marine Technology Kaohsiung Taiwan

ISBN: (纸本)0769515797

The concept of a safety vector can guide efficient fault-tolerant routing on interconnection networks. The safety vector on a hypercube is based on the distance between a pair of nodes. However, the distance measure cannot be applied on star graphs directly, since there are many routing path patterns when the distances between two pairs of nodes are the same. Thus, on star graphs, we define the safety vector based on the routing path patterns. Based on this concept of routing path patterns, we first define an undirected safety vector, which is a 1D vector on each node. In addition, we propose some methods for solving some problems concerning the safety vectors of the star graph, such as the length of the safety vectors and the ranking of the routing path patterns. © 2002 IEEE.

关键词： Fault tolerance

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