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Privacy-Preserving Top-k Keyword Similarity Search over Outsourced Cloud Data 被引量:1
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作者 TENG Yiping CHENG Xiang +2 位作者 SU Sen WANG Yulong SHUANG Kai 《China Communications》 SCIE CSCD 2015年第12期109-121,共13页
In this paper,we study the problem of privacy-preserving top-k keyword similarity search over outsourced cloud data.Taking edit distance as a measure of similarity,we first build up the similarity keyword sets for all... In this paper,we study the problem of privacy-preserving top-k keyword similarity search over outsourced cloud data.Taking edit distance as a measure of similarity,we first build up the similarity keyword sets for all the keywords in the data collection.We then calculate the relevance scores of the elements in the similarity keyword sets by the widely used tf-idf theory.Leveraging both the similarity keyword sets and the relevance scores,we present a new secure and efficient treebased index structure for privacy-preserving top-k keyword similarity search.To prevent potential statistical attacks,we also introduce a two-server model to separate the association between the index structure and the data collection in cloud servers.Thorough analysis is given on the validity of search functionality and formal security proofs are presented for the privacy guarantee of our solution.Experimental results on real-world data sets further demonstrate the availability and efficiency of our solution. 展开更多
关键词 similarity keyword preserving cloud collection privacy validity files ranking separate
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A Reexamination of Methods of Hierarchic Composition in the AHP 被引量:7
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作者 ZHANG Zhi-yong Economics and Management Department, Xi′an Petroleum University, Xi′an 710065, Shaanxi Province, China 《Systems Science and Systems Engineering》 CSCD 2002年第4期503-510,共8页
This paper demonstrates that we should use two different hierarchic composition methods for the two different types of levels in the AHP. The first method is using the weighted geometric mean to synthesize the judgmen... This paper demonstrates that we should use two different hierarchic composition methods for the two different types of levels in the AHP. The first method is using the weighted geometric mean to synthesize the judgments of alternative-type-level elements, which is the only hierarchic composition method for the alternative-type level in an AHP hierarchy, and the rank is preserved automatically. The second one is using the weighted arithmetic mean to synthesize the priorities of the criteria-type-level elements, which is the only hierarchic composition method for all the criteria-type levels, and rank reversals are allowed. 展开更多
关键词 analytic hierarchy process multicriteria analysis decision theory hierarchic composition priority synthesis rank preservation and reversal of the soil thermodynamic parameters such as the soil thermal conductivity soil heat capacity so
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A NUMERICALLY STABLE BLOCK MODIFIED GRAM-SCHMIDT ALGORITHM FOR SOLVING STIFF WEIGHTED LEAST SQUARES PROBLEMS 被引量:2
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作者 Musheng Wei Qiaohua Liu 《Journal of Computational Mathematics》 SCIE EI CSCD 2007年第5期595-619,共25页
Recently, Wei in proved that perturbed stiff weighted pseudoinverses and stiff weighted least squares problems are stable, if and only if the original and perturbed coefficient matrices A and A^- satisfy several row r... Recently, Wei in proved that perturbed stiff weighted pseudoinverses and stiff weighted least squares problems are stable, if and only if the original and perturbed coefficient matrices A and A^- satisfy several row rank preservation conditions. According to these conditions, in this paper we show that in general, ordinary modified Gram-Schmidt with column pivoting is not numerically stable for solving the stiff weighted least squares problem. We then propose a row block modified Gram-Schmidt algorithm with column pivoting, and show that with appropriately chosen tolerance, this algorithm can correctly determine the numerical ranks of these row partitioned sub-matrices, and the computed QR factor R^- contains small roundoff error which is row stable. Several numerical experiments are also provided to compare the results of the ordinary Modified Gram-Schmidt algorithm with column pivoting and the row block Modified Gram-Schmidt algorithm with column pivoting. 展开更多
关键词 Weighted least squares STIFF Row block MGS QR Numerical stability Rank preserve.
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