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data Compression conference, DCC 2003

作者： Usevitch, Bryan E. Department of Electrical Engineering University of Texas at EI Paso TX United States

ISBN: (纸本)0769518966

Summary form only given. Modern image compression standards such as JPEG 2000 are only defined to operate on integer data and, thus, they pose a problem if data need compressing. The typical way to handle floating point data is to do an initial quantization. This approach allows standard techniques to be used on the quantized data and may be acceptable to researchers due to the irreversible data loss. Another compression approach is through the use of strictly lossless methods such as LZW based techniques. The disadvantages of this approach include low compression ratios, no capability for lossy compression, and low flexibility of the compressed data stream. Extensions to the JPEG2000 standard were proposed that allow efficient floating point data coding. These extensions have the advantage of maintaining desirable properties of JPEG2000, including flexible embedded bit streams, lossy and lossless compression image scalability. Bit plane coding is needed for an overall floating point algorithm and can be applied when acceptable wavelet and color transforms are derived. The derivation of the floating point bit plane coding algorithms considers only the narrow problem of JPEG2000. The proposed approach for bit plane coding represents floating point values as "big integers" and codes these integers directly as in JPEG2000. A separate eligibility pass every several bit planes was introduced to lower the number of coefficients coded in each coding pass resulting in improved efficiency. © 2003 IEEE.

关键词： Image coding

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efficient approximation of optimization queries under parametric aggregation constraints 29

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29th International conference on Very Large data Bases, VLDB 2003

作者： Guha, Sudipto Gunopoulos, Dimitrios Koudas, Nick Srivastava, Divesh Vlachos, Michail University of Pennsylvania United States University of California United States AT and T Labs-Research United States

ISBN: (纸本)0127224424

We introduce and study a new class of queries that we refer to as OPAC (optimization under parametric aggregation constraints) queries. Such queries aim to identify sets of database tuples that constitute solutions of a large class of optimization problems involving the database tuples. The constraints and the objective function are specified in terms of aggregate functions of relational attributes, and the parameter values identify the constants used in the aggregation constraints. We develop algorithms that preprocess relations and construct indices to efficiently provide answers to OPAC queries. The answers returned by our indices are approximate, not exact, and provide guarantees for their accuracy. Moreover, the indices can be tuned easily to meet desired accuracy levels, providing a graceful tradeoff between answer accuracy and index space. We present the results of a thorough experimental evaluation analyzing the impact of several parameters on the accuracy and performance of our techniques. Our results indicate that our methodology is effective and can be deployed easily, utilizing index structures such as R-trees.

关键词： Query languages

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RE-tree: an efficient index structure for regular expressions

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VLDB JOURNAL 2003年第2期12卷 102-119页

作者： Chan, CY Garofalakis, M Rastogi, R Bell Labs Lucent Technol Murray Hill NJ 07974 USA

Due to their expressive power, regular expressions (REs) are quickly becoming an integral part of language specifications for several important application scenarios. Many of these applications have to manage huge databases of RE specifications and need to provide an effective matching mechanism that, given an input string, quickly identifies the REs in the database that match it. In this paper, we propose the RE-tree, a novel index structure for large databases of RE specifications. Given an input query string, the RE-tree speeds up the retrieval of matching REs by focusing the search and comparing the input string with only a small fraction of REs in the database. Even though the RE-tree is similar in spirit to other tree-based structures that have been proposed for indexing multidimensional data, RE indexing is significantly more challenging since REs typically represent infinite sets of strings with no well-defined notion of spatial locality. To address these new challenges, our RE-tree index structure relies on novel measures for comparing the relative sizes of infinite regular languages. We also propose innovative solutions for the various RE-tree operations including the effective splitting of RE-tree nodes and computing a "tight" bounding RE for a collection of REs. Finally, we demonstrate how sampling-based approximation algorithms can be used to significantly speed up the performance of RE-tree operations. Preliminary experimental results with moderately large synthetic data sets indicate that the RE-tree is effective in pruning the search space and easily outperforms naive sequential search approaches.

关键词： regular expressions index structure size measures sampling-based approximations

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7th European conference on Principles and Practice of Knowledge Discovery in databases, PKDD 2003

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7th European conference on Principles and Practice of Knowledge Discovery in databases, PKDD 2003

ISBN: (纸本)3540200851

The proceedings contain 44 papers. The special focus in this conference is on Principles and Practice of Knowledge Discovery in databases. The topics include: Sailing as a machine learning challenge;two-eyed algorithms and problems;power laws and self-similarity for graphs, streams and traditional data;propensity score methodology applied to estimate the effects of marketing interventions;efficient statistical pruning of association rules;majority classification by means of association rules;adaptive constraint pushing in frequent pattern mining;anticipated data reduction in constrained pattern mining;minimal k-free representations of frequent sets;discovering unbounded episodes in sequential data;a multi-relational naïve bayes classifier;improving prediction of the minority class in boosting;using belief networks and fisher kernels;a skeleton-based approach to learning bayesian networks from data;on decision boundaries of naïve bayes in continuous domains;application of inductive logic programming to structure-based drug design;visualizing class probability estimators;automated detection of epidemics from the usage logs of a physicians’ reference database;an indiscernibility-based clustering method with iterative refinement of equivalence relations;a novel approach on mining user preferences for personalized applications;explaining text clustering results using semantic structures;analyzing attribute dependencies;ranking interesting subspaces for clustering high dimensional data;efficiently finding arbitrarily scaled patterns;using transduction and multi-view learning to answer emails;exploring fringe settings of SVMs for classification;rule discovery and probabilistic modeling for onomastic data;constraint-based mining of sequential patterns over datasets with consecutive repetitions.

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Parallel algorithms for mining association rules in time series data 03

Parallel algorithms for mining association rules in time ser...

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Proceedings of the 2003 international conference on Parallel and distributed processing and applications

作者： Biplab Kumer Sarker Takaki Mori Toshiya Hirata Kuniai Uehara Graduate School of Science and Technology Kobe University Kobe Japan

ISBN: (纸本)9783540405238

A tremendous growing interest in finding dependency among patterns has been developing in the domain of time series data mining. It is quite effective to find how current and past values in the streams of data are related to the future. However, these kind of data sets with high dimensionality are enormous in size results in possibly large number of mined dependencies. This strongly motivates the need of efficient parallel algorithms. In this paper, we propose two parallel algorithms to discover dependency from the large amount of time series data. We introduce the method of extracting sequence of symbols from the time series data by using segmentation and clustering processes. To reduce the search space and speed up the process we investigate the technique to group the time series data. The experimental results conducted on a shared memory multiprocessors system justifies the inevitability of using parallel techniques for mining huge amount of data in the time series domain.

关键词： association rules shared memory multiprocessors time series data mining motion data symbols of multi-streams

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Distributed multidimensional suffix arrays for string search

Distributed multidimensional suffix arrays for string search

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IEEE Pacific Rim conference on Communications, Computers and Signal Processing

作者： A. Fellah R. Mawson Department of Math. and Computer Science University of Lethbridge Lethbridge AB Canada

Although the classical B-tree and its derivatives are space efficient data structures for small string documents, they require many structures and an excessive amount of pointer manipulations for efficiently processing and searching large documents. In this paper, we propose a new and conceptually powerful data structure, called multidimensional suffix arrays (MSA), for string search. This data structure combines the features of suffix arrays and multilevel structures into a new approach which is very amenable to implementation on both conventional and clustered computers. algorithms for searching, updating, reorganizing, and distributing multidimensional suffix arrays are discussed. Moreover, MSA achieve a significant improvement over string B-trees.

关键词： Multidimensional systems data structures Clustering algorithms Tree data structures Information analysis Pattern analysis Distributed computing Sorting Indexing Genetics

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A novel geometric algorithm for fast wire-optimized floorplanning 03

A novel geometric algorithm for fast wire-optimized floorpla...

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IEEE International conference on Computer-Aided Design

作者： P.G. Sassone S.K. Lim School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta GA USA

ISBN: (纸本)9781581137620

As the size and complexity of VLSI circuits increase, the need for faster floorplanning algorithms also grows. In this work we introduce Traffic, a new method for creating wire- and area-optimized floorplans. Through the use of connectivity grouping, simple geometry, and efficient data structures, Traffic achieves higher result quality than Simulated Annealing (SA) in a fraction of the time. This speed allows designers to explore a large circuit design space in a reasonable amount of time, rapidly evaluate small changes to big circuits, and quickly produce initial solutions for other floorplanning algorithms.

关键词： Traffic control Partitioning algorithms Shape data structures Circuit simulation Simulated annealing Circuit synthesis Permission Optimization methods Geometry

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space efficient fast isosurface extraction for large datasets

Space efficient fast isosurface extraction for large dataset...

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IEEE conference on Visualization

作者： U.D. Bordoloi Han-Wei Shen Department of Computer and Information Science Ohio State Uinversity USA

In this paper, we present a space efficient algorithm for speeding up isosurface extraction. Even though there exist algorithms that can achieve optimal search performance to identify isosurface cells, they prove impractical for large datasets due to a high storage overhead. With the dual goals of achieving fast isosurface extraction and simultaneously reducing the space requirement, we introduce an algorithm based on transform coding to compress the interval information of the cells in a dataset. Compression is achieved by first transforming the cell intervals (minima, maxima) into a form which allows more efficient compaction. It is followed by a dataset optimized non-uniform quantization stage. The compressed data is stored in a data structure that allows fast searches in the compression domain, thus eliminating the need to retrieve the original representation of the intervals at run-time. The space requirement of our search data structure is the mandatory cost of storing every cell ID once, plus an overhead for quantization information. The overhead is typically in the order of a few hundredths of the dataset size.

关键词： Isosurfaces data mining data structures Visualization Transform coding Quantization Runtime Information science Compaction Information retrieval

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efficient Mining of Textual Associations

Efficient Mining of Textual Associations

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2003 International conference on Natural Language Processing and Knowledge Engineering

作者： Alexandre Gil Gaёl Dias Beira Interior University Computer Science Department6200-053 CovilhaPortugal

This paper describes an efficient implementation for mining textual associations from text *** order to tackle real world applications,efficient algorithms and data structures are needed to manage, in reasonable time and space,the overgrowing volume of text *** that purpose,we introduce a global architecture based on masks,suffix arrays and multidimensional arrays to implement the SENTA extractor[Dias,2002].In particular,SENTA has shown great flexibility and accuracy to mine textual associations such as collocations,cognates, morphemes and *** solution shows O(h(F)N log N)time complexity and O(N)space complexity where N is the size of the corpus and h(F)is a function of the context window size.

关键词： Suffix Arrays Masks Text Mining

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SyncSim: a synchronous simple optimistic simulation technique based on a global parallel heap event queue

SyncSim: a synchronous simple optimistic simulation techniqu...

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Simulation Winter conference

作者： Prasad Zhiyong Cao Computer Science Department Georgia State University Atlanta GA USA

We developed and implemented two highly optimized optimistic discrete event simulation techniques based on an efficient and scalable parallel heap data structure as a global event queue. The primary results are (i) the design of an optimistic simulation algorithm, namely SyncSim, which does not rely on traditional state and message saving data structures, but employs only one backup state per state variable, (ii) a demonstration, through implementation of SyncSim, of an optimistic technique which overcomes the two main mutually conflicting and unbounded overheads of the existing optimistic simulation algorithms: SyncSim bounds the additional space requirements to just one copy per state variable and drastically limits the number of rollbacks encountered. Furthermore, SyncSim beats the highly optimized traditional simulator simglobal on a wide variety of large networks on an Origin-2000 computer. The algorithm SyncSim could form a basis for a good parallelizing engine attachable relatively easily to an existing serial simulator.

关键词： Discrete event simulation Computational modeling Design optimization Computer simulation data structures Algorithm design and analysis Clocks Computer science Computer networks Engines

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