检索结果-内蒙古大学图书馆

International conference on Software Engineering (ICSE)

作者： Xiangyu Zhang R. Gupta Youtao Zhang Department of Computer Science University of Arizona Tucson Tucson AZ USA Department of Computer Science University of Texas Dallas Richardson TX USA

ISBN: (纸本)9780769521633

Dynamic slicing algorithms can greatly reduce the debugging effort by focusing the attention of the user on a relevant subset of program statements. Recently, algorithms for forward computation of dynamic slices have been proposed which maintain dynamic slices of all variables as the program executes. An advantage of this approach is that when a request for a slice is made, it is already available. The main disadvantage of using such an algorithm for slicing realistic programs is that the space and time required to maintain a large set of dynamic slices corresponding to all program variables can be very high. In this paper, we analyze the characteristics of dynamic slices and identify properties that enable space efficient representation of a set of dynamic slices. We show that by using reduced ordered binary decision diagrams (roBDDs) to represent a set of dynamic slices, the space and time requirements of maintaining dynamic slices are greatly reduced. In fact, not only can the latest dynamic slices of all variables be easily maintained, but rather all dynamic slices of all variables throughout a program's execution can be maintained. Our experiments show that our roBDD based algorithm for forward computation of dynamic slices can maintain 107-217 million dynamic slices arising during long program runs using only 28-392 megabytes of storage. In addition, the performance of the roBDD based forward computation method compares favorably with the performance of the LP backward computation algorithm.

关键词： data structures Boolean functions Debugging Computer science Heuristic algorithms data analysis Application software Software testing Software maintenance Software measurement

来源：评论

学校读者我要写书评

暂无评论

A new parallel realization method of SPIHT for video compression

A new parallel realization method of SPIHT for video compres...

引用

IEEE Region 10 International conference TENCON

作者： Yun Hua Bo Hu The Department of Electronic Engineering Fudan University Shanghai China

ISBN: (纸本)0780385608

Set partitioning in hierarchical trees (SPIHT) is an efficient method for image or video compression. However, it requires a large amount of memory space to store intermediate result about significance of pixels and sets with three lists. In this paper, we present a new SPIHT algorithm in which we can process the trees of SPIHT in parallel and individually. We also introduce a new way to truncate bit stream of trees. The simulation result shows the new method can keep the efficiency of SPIHTcompression while save a lot of memory space and time in implement.

关键词： Video compression Discrete wavelet transforms Image coding Streaming media Encoding Discrete cosine transforms Digital signal processing Tree data structures Partitioning algorithms Video sequences

来源：评论

学校读者我要写书评

暂无评论

Spatial approximation + sequential scan = efficient metric indexing

Spatial approximation + sequential scan = efficient metric i...

引用

Computer Science Society (SCCC) International conference Chilean FLAGGED

作者： E. Chavez N. Herrera N. Reyes Escuela de Ciencias Físico-Matemáticas Universidad Michoacana Morelia Mich. México Departamento de Informática Universidad Nacional de San Luis San Luis Argentina

Proximity queries in metric spaces, or metric proximity queries for short, have instances suffering from the so-called "curse of dimensionality" referred to the apparent impossibility of beating the brute force approach (an exhaustive search to satisfy a metric proximity query). In other words, the cursed spaces resists indexing. Current research tends to alleviate this particular situation, since easy spaces can be indexed neatly. A recent hypothesis establishes that it is just a fraction of the database which is resilient to indexing, and the proper approach would be to index each part separately. This is precisely the approach of this work. We use two different techniques for indexing complementary parts of a metric database. The dynamic spatial approximation tree (dsa-tree) is a recently proposed data structure for searching in metric spaces. It has been shown that it compares favorably against alternative data structures in spaces of high dimension or queries with low selectivity On the other hand, pivot-based algorithms are effective tools for proximity searching in any metric spaces, if sufficient storage space is available. In this work we combine the concepts of spatial approximation and pivot-based algorithms. The new data structure maintains the full features of a dsa-tree while using the available memory to improve the query time. We show experimentally that our data structure is competitive choice for searching in cursed metric spaces.

关键词： Indexing Extraterrestrial measurements Spatial databases data structures Indexes Tree data structures Fingerprint recognition Information retrieval Artificial intelligence Resists

来源：评论

学校读者我要写书评

暂无评论

Compact and efficient encryption/decryption module for FPGA implementation of the AES Rijndael very well suited for small embedded applications

Compact and efficient encryption/decryption module for FPGA ...

引用

International conference on Information Technology: Coding and Computing (ITCC)

作者： G. Rouvroy F.-X. Standaert J.-J. Quisquater J.-D. Legat Laboratoire de Micro electronique Universite Catholique de Louvain Louvain-la-Neuve Belgium

Hardware implementations of the advanced encryption standard (AES) Rijndael algorithm have recently been the object of an intensive evaluation. Several papers describe efficient architectures for ASICs and FPGAs. In this context, the highest effort was devoted to high throughput (up to 20 Gbps) encryption-only designs, fewer works studied low area encryption-only architectures and only a few papers have investigated low area encryption/decryption structures. However, in practice, only a few applications need throughput up to 20 Gbps while flexible and low cost encryption/decryption solutions are needed to protect sensible data, especially for embedded hardware applications. We purpose an efficient solution to combine Rijndael encryption and decryption in one FPGA design, with a strong focus on low area constraints. The proposed design fits into the smallest Xilinx FPGAs, deals with data streams of 208 Mbps, uses 163 slices and 3 RAM blocks and improves by 68% the best-known similar designs in terms of ratio Throughput/Area. We also propose implementations in other FPGA Families (Xilinx Virtex-II) and comparisons with similar DES, triple-DES and AES implementations.

关键词： Cryptography Field programmable gate arrays Throughput Hardware Costs NIST Computer architecture Iterative algorithms Protection Application specific integrated circuits

来源：评论

学校读者我要写书评

暂无评论

Aligning multiple protein sequence by an improved genetic algorithm

Aligning multiple protein sequence by an improved genetic al...

引用

International Joint conference on Neural Networks (IJCNN)

作者： Guang-Zheng Zhang De-Shuang Huang University of Science and Technology Hefei Anhui China Hefei Institute of Intelligent Machines Chinese Academy and Sciences China Hefei Institute of Intelligent Machines Chinese Academy and Sciences Hefei Anhui China

ISBN: (纸本)0780383591

Genetic algorithm (GA) is one of the important and successful approaches in multiple sequences alignment (MSA) problem. In this paper, we propose an improved GA method, multiple small-popsize initialization strategy (MSPIS) and hybrid one-point crossover scheme (HOPCS) based GA, which can search the solution space in a very efficient manner. The experimental results show that our improved approach can obtain a better result compared with traditional GA approach in aligning multiple protein sequences problem.

关键词： Protein sequence Genetic algorithms Biological cells Machine intelligence Biological information theory Costs Genetic mutations Stochastic processes Evolution (biology) data structures

来源：评论

学校读者我要写书评

暂无评论

efficient indexing methods for probabilistic threshold queries over uncertain data 04

引用

Proceedings of the Thirtieth international conference on Very large data bases - Volume 30

作者： Reynold Cheng Yuni Xia Sunil Prabhakar Rahul Shah Jeffrey Scott Vitter Department of Computer Sciences Purdue University West Lafayette IN

ISBN: (纸本)9780120884698

It is infeasible for a sensor database to contain the exact value of each sensor at all points in time. This uncertainty is inherent in these systems due to measurement and sampling errors, and resource limitations. In order to avoid drawing erroneous conclusions based upon stale data, the use of uncertainty intervals that model each data item as a range and associated probability density function (pdf) rather than a single value has recently been proposed. Querying these uncertain data introduces imprecision into answers, in the form of probability values that specify the likeliness the answer satisfies the query. These queries are more expensive to evaluate than their traditional counterparts but are guaranteed to be correct and more informative due to the probabilities accompanying the answers. Although the answer probabilities are useful, for many applications, it is only necessary to know whether the probability exceeds a given threshold - we term these Probabilistic Threshold Queries (PTQ). In this paper we address the efficient computation of these types of *** particular, we develop two index structures and associated algorithms to efficiently answer PTQs. The first index scheme is based on the idea of augmenting uncertainty information to an R-tree. We establish the difficulty of this problem by mapping one-dimensional intervals to a two-dimensional space, and show that the problem of interval indexing with probabilities is significantly harder than interval indexing which is considered a well-studied problem. To overcome the limitations of this R-tree based structure, we apply a technique we call variance-based clustering, where data points with similar degrees of uncertainty are clustered together. Our extensive index structure can answer the queries for various kinds of uncertainty pdfs, in an almost optimal sense. We conduct experiments to validate the superior performance of both indexing schemes.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Bursty and hierarchical structure in streams

引用

data MINING AND KNOWLEDGE DISCOVERY 2003年第4期7卷 373-397页

作者： Kleinberg, J Cornell Univ Dept Comp Sci Ithaca NY 14853 USA

A fundamental problem in text data mining is to extract meaningful structure from document streams that arrive continuously over time. E-mail and news articles are two natural examples of such streams, each characterized by topics that appear, grow in intensity for a period of time, and then fade away. The published literature in a particular research field can be seen to exhibit similar phenomena over a much longer time scale. Underlying much of the text mining work in this area is the following intuitive premise-that the appearance of a topic in a document stream is signaled by a "burst of activity," with certain features rising sharply in frequency as the topic emerges. The goal of the present work is to develop a formal approach for modeling such " bursts," in such a way that they can be robustly and efficiently identified, and can provide an organizational framework for analyzing the underlying content. The approach is based on modeling the stream using an infinite-state automaton, in which bursts appear naturally as state transitions;it can be viewed as drawing an analogy with models from queueing theory for bursty network traffic. The resulting algorithms are highly efficient, and yield a nested representation of the set of bursts that imposes a hierarchical structure on the overall stream. Experiments with e-mail and research paper archives suggest that the resulting structures have a natural meaning in terms of the content that gave rise to them.

关键词： data stream algorithms text mining Markov source models

来源：评论

学校读者我要写书评

暂无评论

efficient mining of textual associations

Efficient mining of textual associations

引用

International conference on Natural Language Processing and Knowledge Engineering

作者： Gil, A Dias, G Beira Interior Univ Dept Comp Sci P-6200053 Covilha Portugal

ISBN: (纸本)0780379020

This paper describes an efficient implementation for mining textual associations from text corpora. In 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 data. For 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 chunks. Our 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

来源：评论

学校读者我要写书评

暂无评论

SIGMOD 2003 - Proceedings of the 2003 ACM SIGMOD International conference on Management of data

SIGMOD 2003 - Proceedings of the 2003 ACM SIGMOD Internation...

引用

2003 ACM SIGMOD International conference on Management of data

The proceedings contain 121 papers. The topics discussed include: improving the efficiency of database-system teaching;distributed top-k monitoring;approximate join processing over data streams;QC-trees: an efficient summary structure for semantic OLAP;winnowing: local algorithms for document fingerprinting;information sharing across private databases;rights protection for relational data;ViST: a dynamic index method for querying xml data by tree structures;XPRESS: a queriable compression for XML data;D(k)-index: an adaptive structural summary for graph-structured data;containment join size estimation: models and methods;efficient processing of joins on set-valued attributes;temporal coalescing with now granularity, and incomplete information;and warping indexes with envelope transforms for query by humming.

关键词：

来源：评论

学校读者我要写书评

暂无评论

space-economical reassembly for intrusion detection system

Space-economical reassembly for intrusion detection system

引用

5th International conference on Information and Communications Security, ICICS 2003

作者： Zhang, Meng Ju, Jiu-Bin Jilin University College of Computer Science and Technology Changchun130012 China

ISBN: (纸本)3540201505

The reassembly of IP fragments and TCP streams are very important in Intrusion Detection Systems (IDS). However, existing reassembly algorithms that cache fragments entirely are memory-greedy. It is vulnerable to memory exhaustion denial of service (DOS) attacks. In this paper, we present a space- economical algorithm based on enhanced DAWG (Directed Acyclic Word Graph) automaton, which can detect the occurrences of a set of patterns in an out-of-order data stream. In contrast to existing algorithms, our algorithm scans each fragment by a multi-pattern matching automaton and just caches the returned solid-size index data structures, thus the memory requirement involved in caching fragments is largely reduced. Experiments and analysis show that our new algorithm greatly reduces the memory usage of reassembly in IDS and outperforms existing algorithms. © Springer-Verlag Berlin Heidelberg 2003.

关键词： Pattern matching

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：