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11th International Conference on Extending Database Technology, EDBT 2008

作者： Yoshihara, Tomohiro Kobayashi, Dai Yokota, Haruo Department of Computer Science Tokyo Institute of Technology 2-12-1 Ookayama Meguro-ku Tokyo 152-8552 Japan Global Scientific Information and Computing Center Tokyo Institute of Technology 2-12-1 Ookayama Meguro-ku Tokyo 152-8550 Japan Systems Development Laboratory Hitachi Ltd. JSPS

ISBN: (纸本)9781595939265

While shared-nothing parallel infrastructures provide fast processing of explosively growing digital content, managing data efficiently across multiple nodes is important. The value-range partitioning method with parallel B-tree structures in a shared-nothing environment is an efficient approach for handling large amounts of data. To handle large amounts of data, it is also important to provide an efficient concurrency control protocol for the parallel B-tree. Many studies have proposed concurrency control protocols for B-trees, which use latch-coupling. None of these studies has considered that latch-coupling contains a performance bottleneck of sending of messages between processing elements (PEs) in distributed environments because latch-coupling is efficient for a B-tree on a single machine. The only protocol without latch-coupling is the B-link algorithm, but it is difficult to use the B-link algorithm directly on an entire parallel B-tree structure because it is necessary to guarantee the consistency of the side pointers. We propose a new concurrency control protocol named LCFB that requires no latch-coupling in optimistic processes. LCFB reduces the amount of communication between PEs during a B-tree traversal. To detect access path errors in the LCFB protocol caused by removal of latch-coupling, we assign boundary values to each index page. Because a page split may cause page deletion in a Fat-Btree, we also propose an effective method for handling page deletions without latch-coupling. We then combine LCFB with the B-link algorithm within each PE to reduce the cost of Structure Modification Operations (SMOs) in a PE, as a solution to the difficulty of consistency management for the side pointers in a parallel B-tree structure. To compare the performance of the proposed protocol with conventional protocols MARK-OPT, INC-OPT, and ARIES/IM, we implemented them on an autonomous disk system with a Fat-Btree structure. Experimental results in various environments

关键词： Network protocols

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Ubiquitous interactive visualization of 3D mantle convection using a web-portal with Java and Ajax framework

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Visual Geosciences 2008年第1期13卷 105-115页

作者： Greensky, James B.S.G. Czech, Wojciech Walter Yuen, David A. Knox, Michael Richard Damon, Megan Rose Chen, Shi Steve Kameyama, M. Charley Laboratory of Computing Science and Engineering Minnesota Supercomputing Institute University of Minnesota Minneapolis MN 55455 United States Institute of Computer Science AGH University 31-005 Krakow Poland Scientific Integration and Visualization Office Code 610.3 NASA Goddard Space Flight Center Greenbelt MD 20770 United States Laboratory of Computational Geodynamics Graduate University of Chinese Academy of Sciences 100049 Beijing China Geodynamics Research Center Ehime University Matsuyama 790-8577 Japan

We have developed a new strategy and espouse a novel paradigm for large-scale computing and real-time interactive visualization. This philosophy calls for intense interactive sessions for a couple of hours at a time at the expense of storing data on many disk drives during regular or heroic runs on massively parallel systems. We have already carried out successfully real-time volume-rendering visualization by employing hundreds of processors for a grid with over 25 million unknowns. Both Cartesian and spherical 3D mantle convection are visualized. The volume-rendered images are viewed on a large display device, with many panels holding around 13 million pixels. We will employ a software strategy involving an hierarchical rendering service, which will have as software an Ajax interface for interactive visualization of large data sets on many different platforms from desktop PC's to hand-held devices, such as the OQO and the Nokia N-800. An option for stereo viewing is also implemented. We have installed a user interface as web application, using Java and Ajax framework in order to achieve over the Internet reasonable accessibility to our ongoing runs. Our goal is to expand the array of interactive devices, which will make it feasible to carry out ubiquitous visualization and monitoring of large-scale simulations or onsite events and to allow for collaborations across oceans. © Springer-Verlag 2008.

关键词： 3D mantle convection Ajax framework Hand-held device Java Visualization

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A novel data distortion approach via selective SSVD for privacy protection

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International Journal of Information and computer Security 2008年第1期2卷 48-70页

作者： Wang, Jie Zhang, Jun Xu, Shuting Zhong, Weijun Laboratory for High Performance Scientific Computing and Computer Simulation Department of Computer Science University of Kentucky Lexington KY 40506-0046 United States Department of Computer Information Systems Virginia State University Petersburg VA 23806 United States Department of Management Sciences and Engineering Southeast University Nanjing 210096 China

Data privacy preservation has become one of the major concerns in the design of practical data-mining applications. In this paper, a novel data distortion approach based on structural partition and Sparsified Singular Value Decomposition (SSVD) technique is proposed. Three schemes are designed to balance privacy protection in centralised datasets and mining accuracy. Some metrics are used to evaluate the performance of the proposed new strategies. Data utility of the three proposed schemes is examined by a binary classification based on the support vector machine. Furthermore, we examine three sparsification strategies. The effect of method parameters on data distortion level and utility is also studied experimentally. Our experimental results on synthetic and real datasets indicate that, in comparison with standard data distortion techniques, the proposed schemes are efficient in balancing data distortion level and data utility. They afford a feasible solution with a good promise for mining accuracy and a significant reduction in the computational cost from SVD. Copyright © 2008 Inderscience Enterprises Ltd.

关键词： Data privacy

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Automatic Digest Generation by Extracting Important Scenes from the Content of Presentations

Automatic Digest Generation by Extracting Important Scenes f...

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International Workshop on Database and Expert Systems Applications

作者： Hieu Hanh Le Thitiporn Lertrusdachakul Tetsutaro Watanabe Haruo Yokota Department of Computer Science Tokyo Institute of Technology Japan Department of Computer Science Graduate School of Information and Engineering Tokyo Institute of Technology Japan Application Lab Ricoh Company Ltd Application Laboratory Software R&D Group Ricoh Company Limited Japan Department of Computer Science Tokyo Institute of Technology Global Scientific Information and Computing Center Tokyo Institute of Technology

Recently, combining a video recording of a presentation along with the digital slides used in it has become popular in e-learning and presentation of archives. For users of the archives, it is useful to preview a digest of such content to grasp the atmosphere and/or an outline of the presentation. This paper proposes a method of automatic digest generation by extracting important scenes from the presentation content. The extracted scenes are chosen based on several factors such as frequency and specificity of words, scene duration and order. Finally, the effectiveness of the proposed methods are evaluated by comparing with testers' answer sets for actual lectures.

关键词： Data mining Speech Proposals Electronic learning Arrays Video recording Software

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Vortex characterization for engineering applications

Vortex characterization for engineering applications

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作者： Jankun-Kelly, M. Thompson, D. Jiang, M. Shannahan, B. Machiraju, R. Mississippi State University Mississippi State MS 39762 United States Lawrence Livermore National Laboratory Center for Applied Scientific Computing Box 808 L-560 Livermore CA 94551 United States Department of Computer Science and Engineering 395 Dreese Labs Ohio State University 2015 Neil Avenue Columbus OH 43210 United States Computational Simulation and Design Center Box 9627 United States Department of Aerospace Engineering Box A United States

ISBN: (纸本)9781563479373

Realistic engineering simulation data often have features that are not optimally resolved due to practical limitations on mesh resolution. To be useful to application engineers, vortex characterization techniques must be sufficiently robust to handle realistic data with complex vortex topologies. In this paper, we present enhancements to the topology identification and segmentation component of an existing vortex characterization algorithm. The modified techniques are demonstrated by application to three realistic data sets that contain complex vortical flows. The algorithm, although improved, still has difficulties with certain types of aggregate topologies. Directions for future work are identified. Copyright © 2008 by the American Institute of Aeronautics and Astronautics, Inc.

关键词： Vortex flow

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Minimum description length with local geometry

Minimum description length with local geometry

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IEEE International Symposium on Biomedical Imaging

作者： Martin Styner Ipek Oguz Tobias Heimann Guido Gerig Department of Psychiatry North Carolina State University Chapel Hill USA Department of Computer Science Chapel Hill USA Division Medical and Biological Informatics DKFZ Heidelberg Germany Scientific Computing and Imaging Institute University of Utah Salt Lake USA

Establishing optimal correspondence across object populations is essential to statistical shape analysis. Minimizing the description length (MDL) is a popular method for finding correspondence. In this work, we extend the MDL method by incorporating various local curvature metrics. Using local curvature can improve performance by ensuring that corresponding points exhibit similar local geometric characteristics that can't always be captured by mere point locations. We illustrate results on a variety of anatomical structures. The MDL method with a combination of point locations and curvature outperforms all the other methods we analyzed, including traditional MDL and spherical harmonics (SPHARM) correspondence, when the analyzed object population exhibits complex structure. When the objects are of simple nature, however, there's no added benefit to using the local curvature. In our experiments, we did not observe a significant difference in the correspondence quality when different curvature metrics (e.g. principal curvatures, mean curvature, Gaussian curvature) were used.

关键词： Shape Biomedical imaging Computational geometry Information geometry Harmonic analysis computer science Psychiatry Biological information theory Biomedical informatics scientific computing

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Numerical algorithms for an inverse problem in shape optimization

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Journal of Physics: Conference Series 2008年第1期135卷

作者： Grzanek, M. Laurain, A. Szulc, K. University of Łódź Faculty of Mathematics and Computer Science 90-238 Łódź Banacha 22 Poland University of Graz Dep. of Mathematics and Scientific Computing Graz Austria Institut Élie Cartan University Henri Poincaré Nancy 1 France

Two approaches are proposed for solving inverse problems in shape optimization. We are looking for the unknown position of a small hole in a domain Ω. First, the asymptotic analysis of the underlying p.d.e. defined in a perturbed domain is performed and the so-called topological derivative is defined. Then, in the first approach, the self-adjoint extensions of elliptic operators are used to model the solution of a partial differential equation defined in the singularly perturbed domain. A least-square functional is then minimized to identify the hole. In the second approach, neural networks are used to determine the inverse of the mapping which associates a set of shape functionals to the position of the unknown hole. In both approaches the topological derivatives are used to approximate the shape functionals. © 2008 IOP Publishing Ltd.

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scientific Data Management: An Orphan in the Database Community?

Scientific Data Management: An Orphan in the Database Commun...

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International Conference on Data Engineering

作者： Randal Burns Susan B. Davidson Yannis Ioannidis Miron Livny Jignesh M. Patel Moderator Assistant Professor Department of Computer Science Johns Hopkins University. Department Chair Weiss Professor of Computer and Information Science ACM Fellow a Fulbright scholar founding co-Director of the Center for Bioinformatics at UPenn (PCBI) Professor Department of Informatics & Telecommunications University of Athens ACM Fellow ACM SIGMOD Vice-Chair member of the Scientific Advisory Board Max Planck Institute for Informatics. Professor of Computer Sciences director of the Center for High Throughput Computing Associate Professor faculty member EECS department University of Michigan

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Ishimori-(I) Equation with Self-Consistent Sources

Ishimori-(I) Equation with Self-Consistent Sources

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International Conference Nonlinear Waves-Theory and Applications (2008年非线性波理论与应用国际会议

作者： Juan Hu Xing-Biao Hu Hon-Wah Tam Institute of Computational Mathematics and Scientific Engineering Computing Academy of Mathematics and System SciencesChinese Academy of SciencesP.O.Box 2719Beijing 100080P.R.CHINA Graduate School of the Chinese Academy of Sciences BeijingP.R.CHINA Department of Computer ScienceHong Kong Baptist universityKowloon TongHong KongP.R.CHINA

In this paper, grammian solutions of Ishimori-(I) (Ish-(I)) equation are firstly obtained by Hirota's direct *** the source generation procedure is utilized to generate the Ishimori-(I) equation with self-consistent sources (Ish-(I) ESCS) and its grammian solutions are *** a simple example, the (1, 1) dromion solution is examined.

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A Stefan problem related to a non-equilibrium shrinking unreacted core model with fast reaction for the sphere

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PAMM 2008年第1期7卷

作者： Adrian Muntean CASA – Center for Analysis Scientific computing and Applications Department of Mathematics and Computer Science TU Eindhoven PO Box 513 5600 MB Eindhoven The Netherlands

The problem studied in this note refers to a substantial part of a larger system of partial differential equations modeling diffusion and fast reaction of a gaseous species A in a reactive spherical porous region. We report on the local existence and uniqueness of weak solutions to the corresponding moving-boundary system containing two coupled mass-balance equations in a moving annulus. Since the system incorporates an explicit description of the velocity of the moving boundary, our formulation resembles to the one-phase Stefan-like problem with kinetic condition. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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