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International Conference on Information engineering and Computer Science (ICIECS)

作者： Xianli Xing Dexi Liu Principal's Office Jiangxi University of Finance and Economics Nanchang China School of Information Technology Jiangxi Key Laboratory of Data and Knowledge Engineering Jiangxi University of Finance and Economics Nanchang China

ISBN: (纸本)9781424449934

Top-k queries in uncertain databases are quite popular and useful due to its wide application usage. However, compared to top-k in traditional databases, queries over uncertain database are more complicated because of the existence of exponential possible worlds. A Top-k aggregate query ranks groups of tuples by their aggregate values, sum or average for example, and returns k groups with the highest aggregate values. As a powerful semantic of top-k, global top-k, returns A highest-ranked tuples according to their probabilities of being in the top-k anTopswers in possible worlds. We propose a dynamic programming based method to process global top-k aggregate queries in uncertain database, where the number of retrieved tuples and group states generated on these tuples are minimized. Experiment results show that our algorithm is effective.

关键词： Aggregates databases Finance Power generation economics Dynamic programming Information technology Laboratories knowledge engineering Information retrieval Performance analysis

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Chinese integral word segmentation recognition based on reliability

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Journal of Information and Computational Science 2009年第1期6卷 533-542页

作者： Wan, Changxuan Wang, Fang School of Information Technology Jiangxi University of Finance and Economics Nanchang 330013 China Jiangxi Key Laboratory of Data and Knowledge Engineering Jiangxi University of Finance and Economics Nanchang 330013 China School of Humanities Nanchang University Nanchang 330013 China

As one part of preprocessing, automatic word segmentation is an key issue in Chinese information retrieval. Since integral words are put wholly together to compose into the more meaningful words and more express users' query minds in information retrieval, we combine the calculation of mutual information, prefix- and-suffix information of integral word with the reliability of composing into the integral word, and put forward three Chinese integral word segmentation recognition method based on reliability according to the characteristics of the integral words. Then, we design and realize the prototype system of three Chinese integral word segmentation recognition methods based on reliability. Finally, tests and analysis on 2nd SIGHAN (2005) PKU test corpus show that the recognition performance of the system is good, and can satisfy different needs at the same time. © 2009 Binary Information Press.

关键词： Reliability

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Web page malicious code detection based on embedded fingerprints

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Qinghua Daxue Xuebao/Journal of Tsinghua University 2009年第SUPPL. 2期49卷 2208-2214页

作者： Huang, Jianjun Liang, Bin Key Laboratory of Data Engineering and Knowledge Engineering of Ministry of Education School of Information Renmin University of China Beijing 100872 China

Web sites have become the main targets of many attackers. Signature-based detection needs to maintain a large signature database and Honeypot based methods are not efficient. Since attackers always make the malicious codes in Web pages difficult to detect by the browser users, their methods can be classified into various fingerprints. Various malicious codes were analyzed to identify 6 types of fingerprints. The system utilizes a spider integrated with script interpretation to fetch target Web pages and extract specific tags for detection by HTML parsing for matching with the fingerprints to detect malicious codes. This method needs fewer fingerprints than traditional detection methods and is more efficient. Results for 60 websites show that the system has a false negative rate of 2.63% and a false positive rate of 1.99%.

关键词： Websites

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PEJA:Progressive Energy-Efficient Join Processing for Sensor Networks

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Journal of Computer Science & Technology 2008年第6期23卷 957-972页

作者：赖永炫陈毅隆陈红 School of Information Renmin University of China Key Laboratory of Data Engineering and Knowledge Engineering Ministry of Education

Sensor networks are widely used in many applications to collaboratively collect information from the physical environment. In these applications, the exploration of the relationship and linkage of sensing data within multiple regions can be naturally expressed by joining tuples in these regions. However, the highly distributed and resource-constraint nature of the network makes join a challenging query. In this paper, we address the problem of processing join query among different regions progressively and energy-efficiently in sensor networks. The proposed algorithm PEJA （Progressive Energy-efficient Join Algorithm） adopts an event-driven strategy to output the joining results as soon as possible, and alleviates the storage shortage problem in the in-network nodes. It also installs filters in the joining regions to prune unmatchable tuples in the early processing phase, saving lots of unnecessary transmissions. Extensive experiments on both synthetic and real world data sets indicate that the PEJA scheme outperforms other join algorithms, and it is effective in reducing the number of transmissions and the delay of query results during the join processing.

关键词： progressive join minimal join set in-network processing sensor network

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Static vulnerabilities detection method based on security state tracing and checking

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Jisuanji Xuebao/Chinese Journal of Computers 2009年第5期32卷 899-909页

作者： Liang, Bin Hou, Kan-Kan Shi, Wen-Chang Liang, Zhao-Hui School of Information Renming University of China Beijing 100872 China MOE Key Laboratory of Data Engineering and Knowledge Engineering Beijing 100872 China

The main problem of existing static vulnerability detection methods based source code analysis is their high false positive and false negative rates. One main reason is lack of accurate and effective identification and analysis of security-related program elements, e.g. data validation checking, tainted data source, etc. A static vulnerability detection method based on data security state tracing and checking is proposed. In this method, the state space of state machine model is extended;the security state of a variable is identified by a vector that may correspond to multiple security-related properties rather than by a single property;Fine-grained state transition is provided to support accurate recognition of program security-related behaviors;The recognition of validation checking is introduced in vulnerability state machine to reduce false positives;and a systematic discrimination mechanism for tainted data is constructed to prevent false negatives result from neglecting tainted data sources. The experimental results of a prototype system show that this method can effectively detect buffer overflow and other type's vulnerabilities in software systems, and with obviously lower false positive than existing mainstream static detection methods and avoid some serious false negatives of these methods.

关键词： Static analysis

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VSM-RF: A method of relevance feedback in keyword Search over Relational databases

VSM-RF: A method of relevance feedback in Keyword Search ove...

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IEEE International Symposium on Information (IT) in Medicine and Education, ITME

作者： Zhao-hui Peng Jun Zhang Shan Wang Chang-liang Wang Li-zhen Cui School of Computer Science and Technology Shandong University Jinan 250101 China School of Computer Science and Technology Dalian Maritime University 116026 China Key Laboratory of Data Engineering and Knowledge Engineering Ministry of Education Beijing 100872 China The Hong Kong University of Science and Technology China

In keyword search over relational databases (KSORD), retrieval of user's initial query is often unsatisfying. User has to reformulate his query and execute the new query, which costs much time and effort. In this paper, a method of automatically reformulating user queries by relevance feedback is introduced, which is named VSM-RF. Aimed at the results of KSORD systems, VSM-RF adopts a ranking method based on vector space model to rank KSORD results. After the first time of retrieval, using user feedback or pseudo feedback just as user like, VSM-RF computes expansion terms based on probability and reformulates the new query using query expansion. After KSORD systems executing the new query, more relevant results are produced by the new query in the result list and presented to user. Experimental results verify this method's effectiveness.

关键词： Feedback keyword search Relational databases Computer science Information retrieval Laboratories data engineering knowledge engineering Computer science education Costs

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Bring User Feedback into keyword Search over databases

Bring User Feedback into Keyword Search over Databases

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Web Information Systems and Applications Conference (WISA)

作者： Zhaohui Peng Jun Zhang Shan Wang Changliang Wang School of Computer Science & Technology Shandong University Jinan China Key Laboratory of Data Engineering & Knowledge Engineering Ministry of Education Beijing China School of Computer Science & Technology Dalian Maritime University Dalian China Hong Kong University of Science and Technology Hong Kong China

keyword search over relational databases (KSORD) enables casual users to use keyword queries (a set of keywords) to search relational databases just like searching the Web, without any knowledge of the database schema or any need of writing SQL queries. In KSORD, retrieval of user's initial query is often unsatisfying. User has to reformulate his query and execute the new query, which costs much time and effort. A method of automatically reformulating user queries by user feedback aimed at the results of KSORD is introduced in this paper, which is named UFBP (user feedback based on probability). After the first time of retrieval, according to the users' feedback information, UFBP computes terms to be added into the expanded query based on probability and reformulates the new query using query expansion. After KSORD executing the new query automatically, more relevant results are presented to user. Experimental results verify its effectiveness.

关键词： Feedback keyword search Relational databases Tree graphs Information retrieval Computer science Educational technology Writing Information systems Application software

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The Research on the Algorithms of keyword Search in Relational database

Lecture Notes in Computer Science (including subseries Lectu...

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Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 2008年 4977卷 134-143页

作者： Li, Peng Zhu, Qing Wang, Shan Key Laboratory of Data Engineering and Knowledge Engineering School of Information Renmin University of China Beijing100872 China

ISBN: (纸本)354089375X

With the development of relational database, people require better database not only in the aspect of database performance, but also in the aspect of the database’s interactive ability. So that the database is much more friendly than just before and it is possible for a common user who do not have any special knowledge on database can access the database, without knowing the schema of database and writing intricate SQL. For the reason that the information retrieval on the web has developed well to some extent, when we develop the technology of keyword search in relational database, we can draw some ideas from information retrieve. But the great differences between the text database on the web and the relational database also bring some new challenges: 1) The answer needed by user is not only one tuple in database, but the tuple sets consisting of the tuple connect from different table using the "primary key-foreign key" relationship. 2)The results of the evaluation criteria is more important, because it is directly related to the effectiveness of Search System. 3)The structure of relational database is much more intricate than text database, and the algorithms of information retrieval are not fit the relational database. So in this paper, we introduce a novel keyword search algorithm and a modified criteria of evaluating answers in order to enhance efficiency of the keyword search and return much more effective information to users, finally, the search algorithm’s performance is tested and evaluated. © Springer-Verlag Berlin Heidelberg 2008

关键词： Information retrieval

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Top-K keyword search for supporting semantics in relational databases

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Ruan Jian Xue Bao/Journal of Software 2008年第9期19卷 2362-2375页

作者： Wang, Bin Yang, Xiao-Chun Wang, Guo-Ren College of Information Science and Engineering Northeastern University Shenyang 110004 China Key Laboratory of Data Engineering and Knowledge Engineering Renmin University of China Beijing 100872 China

In order to enhance the search results of keyword search in relational databases, semantic relationship among relations and tuples is employed and a semantic ranking function is proposed. In addition to considering current ranking principles, the proposed semantic ranking function provides new metrics to measure query relevance. Based on it, two Top-k search algorithms BA (blocking algorithm) and EBA (early-stopping blocking algorithm) are presented. EBA improves BA by providing a filtering threshold to terminate iterations as early as possible. Finally, experimental results show the semantic ranking function guarantees a search result with high precision and recall, and the proposed BA and EBA algorithms improve query performance of existing approaches.

关键词： Information retrieval

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OLTP workloads on modern processor: Characterization and analysis

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Journal of Computational Information Systems 2008年第1期4卷 389-394页

作者： Liu, Dawei Qin, Biao Wang, Shan Gong, Weiwei School of Information Renmin University of China Beijing 100872 China Key Laboratory of Data Engineering and Knowledge Engineering Renmin University of China Beijing 200872 China

This paper analysis of how OLTP workloads interact with modern processors and caches behavior. First, we extend TPC-C, the OLTP-oriented benchmark, to ETPC-C benchmark, for measuring the performance of main-memory database (MMDBMS) more precisely. As the performance of MMDBMS is not affected by disk I/O, it is more sensitive to cache usage. Then using ETPC-C benchmark, we investigated the behavior of caches and processors extensively. We find that the miss stall time is mostly spent on on-CPU-chip caches, that is, the first and second level cache misses are dominant. Furthermore, we find instruction cache (I-cache) stall time of on-CPU-chip is a major component to the memory stall time. The smaller the emulated users, the more proportion the I-cache stall time of on-CPU-chip contributes to the memory stall time. However, if employing index, the system under test (SUT) has more total I-cache stall time than the SUT without index at the same number of emulated users and data population. Another observation is that the SUT with index has a little more branch misprediction rate than the SUT without index in average. Finally, we find only the third level (L3) D-cache stall time rate increases with the number of users. This is because L3 D-cache miss incremental rate is the largest. Under TPC-and ETPC-evaluation, we find that for optimized database performance on modern computers, reducing instruction miss penalty is equally important to reducing data miss penalty;since they are conflict efforts, the best way is to have them balanced.

关键词： Program processors

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