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International Conference on Shape Modeling and Applications

作者： P.-T. Bremer V. Pascucci B. Hamann Department of Computer Science University of Illinois Urbana-Champaign USA Lawrence Livermore National Laboratory Center for Applied Scientific Computing USA Institute for Data Analysis and Visualization Department of Computer Science University of California Davis USA

We present an approach to hierarchically encode the topology of functions over triangulated surfaces. Its Morse-Smale complex, a well known structure in computational topology, describes the topology of a function. Following concepts of Morse theory, a Morse-Smale complex (and therefore a function's topology) can be simplified by successively canceling pairs of critical points. We demonstrate how cancellations can be effectively encoded to produce a highly adaptive topology-based multi-resolution representation of a given function. Contrary to the approach, we avoid encoding the complete complex in a traditional mesh hierarchy. Instead, the information is split into a new structure we call a cancellation forest and a traditional dependency graph. The combination of this new structure with a traditional mesh hierarchy proofs to be significantly more flexible than the one previously reported. In particular, we can create hierarchies that are guaranteed to be of logarithmic height.

关键词： Topology data visualization data analysis Computer science Encoding Level set Shape Scientific computing Laboratories Transfer functions

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Radiation-coupled front-tracking simulations for laser-driven shock experiments

Radiation-coupled front-tracking simulations for laser-drive...

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作者： Zhang, Yongmin Drake, R. Paul Glimm, James Grove, John W. Sharp, David H. Department of Applied Mathematics and Statistics University at Stony Brook Stony Brook NY 11974-3600 United States University of Michigan 2455 Hayward St. Ann Arbor MI 48105 United States Center for Data Intensive Computing Brookhaven National Laboratory Upton NY 11793-6000 United States Continuum Dynamics Group Computer and Computational Science Division Los Alamos National Laboratory Los Alamos NM 87545 United States Complex Systems Group Theoretical Division Los Alamos National Laboratory Los Alamos NM 87545 United States

The purpose of this paper is to develop a numerical algorithm to track the preheat interface motion driven by radiation transfer in high-intensity laser experiments. Our front-tracking algorithm is coupled to a radiation process through an inter-package coupling by connecting the output from a radhydro code HYADES to the input of FronTier code of front tracking. Our coupled algorithm is validated by comparing simulation results from both codes in both low and high radiation cases. Significant interface motion and deformation of the harmonic perturbation due to radiation preheat are observed in high radiation heat case. © 2005 Elsevier Ltd. All rights reserved.

关键词： Algorithms

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Reversible N-bit to N-bit integer haar-like transforms

Reversible N-bit to N-bit integer haar-like transforms

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Proceedings of the Seventh IASTED International Conference on Computer Graphics and Imaging

作者： Senecal, Joshua G. Duchaineau, Mark A. Joy, Kenneth I. Inst. for Sci. Computing Research L-419 PO Box 808 Livermore CA 94551 United States Ctr. for Appl. Scientific Computing Lawrence Livermore Natl. Laboratory L-561 PO Box 808 Livermore CA 94551 United States Inst. Data Anal. and Visualization Computer Science Department University of California Davis One Shields Ave. Davis CA 95616 United States

We introduce TLHaar, an n-bit to n-bit reversible trans-form similar to the S-transform, TLHaar uses lookup tables that approximate the S-transform, but reorder the co-efficients so they fit into n bits. TLHaar is suited for loss-less compression in fixed-width channels, such as digital video channels and graphics hardware frame buffers. Tests indicate that when the incoming image data has lines or hard edges TLHaar coefficients compress better than S-transform coefficients. For other types of image data TL-Haar coefficients compress up to 2.5% worse than those of the S-transform, depending on the data and the compression method used.

关键词： Image compression

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Can we determine the top unresolved problems of visualization?

Can we determine the top unresolved problems of visualizatio...

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IEEE Visualization 2004 - Proceedings, VIS 2004

作者： Rhyne, Theresa-Marie Hibbard, Bill Johnson, Chris Chen, Chaomei Eick, Steve North Carolina State University University of Wisconsin Madison University of Utah Drexel University SSS-Research Inc. University of Illinois Chicago Learning Technology Service North Carolina State University Sci. Computing and Imaging Institute University of Utah Department of Computer Science Depts. of Phys. and Bioengineering Coll. of Info. Sci. and Technology Drexel University UIC's Natl. Center for Data Mining

ISBN: (纸本)0780387880

The top unresolved problems in visualization were investigated by panelists from both the information and scientific visualization domains. One of the key unresolved challenges in visualization is collaboration in its broadest sense. Visualization 'scientists' need to spend more time understanding the underlying science applications in order to create effective visual representations. In order to 'evolve' visualization into a more scientific enquiry, visualization scientists need to understand and use the scientific method such as formulation of an hypothesis to explain the phenomena. Effective human computer interaction continues to be one of the top research and development goals for both visualization and computer graphics.

关键词： Visualization

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An improved N-bit to N-bit reversible Haar-like transform

An improved N-bit to N-bit reversible Haar-like transform

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Pacific Conference on Computer Graphics and Applications

作者： J.G. Senecal P. Lindstrom M.A. Duchaineau K.I. Joy Inst. for Sci. Comput. Res. Lawrence Livermore Nat. Lab. CA USA Center for Applied Scientific Computing Lawrence Livemore National Laboratory USA Institute for Data Analysis and Visualization Computer Science Department University of California Davis USA

We introduce the piecewise-linear Haar (PLHaar) transform, a reversible n-bit to n-bit transform that is based on the Haar wavelet transform. PLHaar is continuous, while all current n-bit to n-bit methods are not, and is therefore uniquely usable with both lossy and lossless methods (e.g. image compression). PLHaar has both integer and continuous (i.e. non-discrete) forms. By keeping the coefficients to n bits PLHaar is particularly suited for use in hardware environments where channel width is limited, such as digital video channels and graphics hardware.

关键词： Wavelet transforms Continuous wavelet transforms Hardware Dynamic range Image coding Scientific computing Image reconstruction Laboratories data analysis data visualization

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Privacy preserving frequent itemset mining 14

Privacy preserving frequent itemset mining

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IEEE International Conference on Privacy, Security and data Mining

作者： Stanley R. M. Oliveira Osmar R. Zaiane Embrapa Information Technology Andre Tosello 209 - Barao Geraldo 13083-886 - Campinas SP Brasil and Department of Computing Science University of Alberta Edmonton AB Canada T6G 2E8 s in Electronics from the University ofParis XI France. He has worked in a variety of research areas such as data mining web mining multimedia databases information retrieval web technology natural language processing distance education and collab

ISBN: (纸本)9780909925925

One crucial aspect of privacy preserving frequent itemset mining is the fact that the mining process deals with a trade-off: privacy and accuracy, which are typically contradictory, and improving one usually incurs a cost in the other. One alternative to address this particular problem is to look for a balance between hiding restrictive patterns and disclosing nonrestrictive ones. In this paper, we propose a new framework for enforcing privacy in mining frequent itemsets. We combine, in a single framework, techniques for efficiently hiding restrictive patterns: a transaction retrieval engine relying on an inverted file and Boolean queries; and a set of algorithms to "sanitize" a database. In addition, we introduce performance measures for mining frequent itemsets that quantify the fraction of raining patterns which are preserved after sanitizing a database. We also report the results of a performance evaluation of our research prototype and an analysis of the results.

关键词： security Privacy mining Inverted files Itemsets Security Performance Evaluation database

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Foundations for an access control model for privacy preservation in multi-relational association rule mining 14

Foundations for an access control model for privacy preserva...

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IEEE International Conference on Privacy, Security and data Mining

ISBN: (纸本)9780909925925

Recent data mining algorithms have been designed for application domains that involve several types of objects stored in multiple relations in relational databases. This fact has motivated the increasing number of successful applications of relational data mining over recent years. On the other hand, such applications have introduced a new threat to privacy and information security since from non-sensitive data one is able to infer sensitive information, including personal information, facts or even patterns that are not supposed to be disclosed. The existing access control models adopted to successfully manage the access of information in complex systems present some limitations in the context of data mining tasks. The main reason is that such models were designed to protect the access to explicit data (e.g. tables, attributes, views, etc), whereas data mining tasks deal with the discovery of implicit data (e.g. patterns). In this paper, we take a first step toward an access control model for ensuring privacy in relational data mining, notably in multi-relational association rules (MRAR). In this model, users associated with different mining access levels, even using the same algorithm, are allowed to mine different sets of association rules. We provide the groundwork to build our access control model over existing technologies and discuss some directions for future work.

关键词： security access control Association rules data mining Privacy Foundations FOUNDATION Security mining Access

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Preface

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Lecture Notes in Computer science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 2001年 2037卷 V-VI页

作者： Boers, Egbert J. W. Cagnoni, Stefano Gottlieb, Jens Hart, Emma Lanzi, Pier Luca Raidl, Günther R. Smith, Robert E. Tijink, Harald Leiden Institute of Advanced Computer Science Leiden University Niels Bohrweg 1 Leiden Netherlands Dept. of Computer Engineering University of Parma Parco Area delle Scienze 181/a Parma Italy SAP AG Neurottstrasse 16 Walldorf Germany Napier University School of Computing 219 Colinton Road Edinburgh United Kingdom Polytechnic of Milan Piazza Leonardo da Vinci 32 Milan Italy Algorithms and Data Structur es Group Institute of Computer Graphics Vienna University of Technology Favoritenstrasse 9-11/186 Vienna Austria The Intelligent Computer Systems Centre The University of The West of England Coldharbour Lane Frenchay Bristol United Kingdom Data and Knowledge Systems Department National Aerospace Laboratory NLR P.O. Box 153 Emmeloord Netherlands

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Dynamic maintenance of wavelet-based histograms

Dynamic maintenance of wavelet-based histograms

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26th International Conference on Very Large data Bases, VLDB 2000

作者： Matias, Yossi Vitter, Jeffrey Scott Wang, Min Department of Computer Science Tel Aviv University Tel Aviv 69978 Israel Center for Geometric Computing Department of Computer Science Duke University Durham NC 27708-0129 United States Data Management Department IBM T. J. Watson Research Center 30 Saw Mill River Road Hawthorne NY 10532 United States

ISBN: (纸本)1558607153

In this paper, we introduce an efficient method for the dynamic maintenance of wavelet-based histograms (and other transform-based histograms). Previous work has shown that wavelet-based histograms provide more accurate selectivity estimation than traditional histograms, such as equi-depth histograms. But since wavelet-based histograms are built by a nontrivial mathematical procedure, namely, wavelet transform decomposition, it is hard to maintain the accuracy of the histogram when the underlying data distribution changes over time. In particular, simple techniques, such as split and merge, which works well for equi-depth histograms, and updating a fixed set of wavelet coefficients, are not suitable here. We propose a novel approach based upon probabilistic counting and sampling to maintain waveletbased histograms with very little online time and space costs. The accuracy of our method is robust to changing data distributions, and we get a considerable improvement over previous methods for updating transform-based histograms. A very nice feature of our method is that it can be extended naturally to maintain multidimensional wavelet-based histograms, while traditional multidimensional histograms can be less accurate and prohibitively expensive to build and maintain.

关键词： Wavelet decomposition

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Preface

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Lecture Notes in Computer science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 2000年 1803卷 6-6页

作者： Cagnoni, Stefano Poli, Riccardo Li, Yun Smith, George Corne, David Oates, Martin Hart, Emma Lanzi, Pier Luca Boers, Egbert J. W. Paechter, Ben Fogarty, Terence C. University of Parma Department of Computer Engineering Parco delle Scienze 181/a Parma Italy The University of Birmingham School of Computer Science Edgbaston Birmingham United Kingdom University of Glasgow Electronics and Electrical Engineering Rankine Building Glasgow United Kingdom University of East Anglia Department of Information Systems Norwich United Kingdom University of Reading P.O. Box 225 Whiteknights Reading United Kingdom BT Labs at Adastral Park Dept. Complex Systems Laboratory Martlesham Heath Suffolk United Kingdom University of Edinburgh Division of Informatics 80 South Bridge Edinburgh United Kingdom Milan Polytechnic Department of Electronics and Informatics Piazza Leonard0 da Vinci 32 Milan Italy National Aerospace Laboratory NLR Data and Knowledge Systems Dept I.C.T. Division Anthony Fokkerweg 2 Amsterdam Netherlands Napier University School of Computing 219 Colinton Road Edinburgh United Kingdom South Bank University School of Computing Information Systems and Mathematics 103 Borough Road London United Kingdom

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