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Some preservation of stability of modules

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Chinese science Bulletin 1997年第19期42卷 1596-1599页

作者： WANG Hanpindepartment of computer science and technology. p.king university, beijing 100871, china department of computer science and technology Peking University Beijing China

IN model theory, Zil’ ber has proved that any model of nontrivial -categorical theory is verysimilar to a module or field. So some people wanted to prove the famous Vaught’s conjec-ture for superstable theories of modules. Later, Buechler proved that the Vaught’s conjectureis true for the theories of modules with Morley rank 1. In order to reduce Vaught’s conjec-ture for superstablc theories of modules, prest suggested discussing the preservation of stabili-ty--theory properties of modules when the underlying ring of the modules changes. Zieglergave some preservation theorems of clementary properties of the theory of modules in ref.

关键词： model theory ω-stahility superstability ring of fractions fractional module.

SUpERCONVERGENCES OF THE ADINI'S ELEMENT FORSECOND ORDER EQUATION

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Journal of Computational Mathematics 1999年第6期17卷 569-574页

作者： ping Luo(department of computer science and technology, Qinghua university, beijing 100084,china)Qun Lin(Institute of Systems science, Academia Sinica, beijing, 100080, china) 清华大学计算机系北京 100084 中科院系统科学所北京 100080

n this papers the asymptotic error expansions of Adini's element for the secondorder imhomogeneous Neumann problem are given and the superconvergence estimations are obtained. Moreover, a numerical example to support ... 详细信息

关键词： Adini's element Superconvergence estimation Asymptotic expansion.

l-SkyDiv query:Effectively improve the usefulness of skylines

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science china(Information sciences) 2010年第9期53卷 1785-1799页

作者： HUANG ZhenHua1,2*,XIANG Yang1 & LIN ZiYu3 1department of computer science and technology,Tongji university,Shanghai 201804,china 2The Key Laboratory of Embedded System and Service Computing,Ministry of Education,Tongji university,Shanghai 200092,china 3department of computer science and technology,p.king university,beijing 100871,china department of computer science and technology Tongji University The Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University department of computer science and technology Peking University

Skyline query processing has recently received a lot of attention in database *** a set of multi-dimensional objects,the skyline query finds the objects that are not dominated by *** the best of our knowledge,the existing researches mainly focus on how to efficiently return the whole skyline ***,as the cardinality and dimensionality of input dataset increase,the number of skylines grows exponentially,and hence this "huge" skyline set is completely useless to *** by the above fact,in this paper,we present a novel type of l-SkyDiv query,which only returns l skylines having maximum diversity,to improve the usefulness of skyline ***,we prove that the l-SkyDiv query belongs to the Np-Hard problem theoretically,and propose three efficient heuristic algorithms whose time complexities are polynomial to fast implement the proposed ***,we present detailed theoretical analyses and extensive experiments,demonstrating that our algorithms are both efficient and effective.

关键词： skyline query diversity heuristic algorithm query optimization performance evaluation

Compactness in fuzzy logic

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Chinese science Bulletin 1998年第14期43卷 1166-1171页

作者： YING Mingsheng department of computer science and technology, Tsinghua university, beijing 100084, china department of computer science and technology Tsinghua University Beijing China

Compactness in pavelka’s fuzzy logic for some compact lattices of truth values is shown, and the concept of gradual compactness is introduced to establish some corresponding results in a more general setting.

关键词： fuzzy logic compactness gradual compactness.

performance Modeling and Approximate Analysis of Multiserver Multiqueue Systems with poisson and Self-similar Arrivals

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Journal of university of science and technology beijing 2001年第2期8卷 145-151页

作者： Zhiguang Shan, Chuang Lin, Yang Yang, Yan Wang (Information Engineering School, university of science and technology beijing, beijing 100083, china) (department of computer science and technology, Tsinghua university, beijing 100084, china) Information Engineering School University of Science and Technology Beijing 100083 China

The problem of state space explosion is still ran outstanding challenge in Markovian performance analysis for multiserver multiqueue (MSMQ) systems. The system behavior of a MSMQ system is described using stochastic high-level petri net (SHLpN) models, and an approximate performance analysis technique is proposed based on decomposition and refinement methods as well as iteration technique. A real MSMQ system, Web-server cluster, is investigated. The performance of an integrated scheme of request dispatching and scheduling is analyzed with both poisson and self-similar request arrivals. The study shows that the approximate analysis technique significantly reduces the complexity of the model solution and is also efficient for accuracy of numerical results.

关键词： multiserver multiqueue (MSMQ) system Web-server cluster performance analysis stochastic high-level petri net (SHLpN) request dispatching request scheduling

A multiple user sharing behaviors based approach for fake file detection in p2p environments

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science china(Information sciences) 2010年第11期53卷 2169-2184页

作者： JIANG Jing, LI YongJun, FENG QinYuan, HUANG peng & DAI YaFei department of computer science and technology, p.king university, beijing 100871, china department of computer science and technology Peking University

File pollution is a problem that is threatening security and availability in peer-to-peer environments, and could eventually be fatal to the survival of these systems. Current methods of fake file detection, which are based on trust mechanisms or file characteristics, do not consider the problems such as interference of multiple user sharing behaviors, the difficulty in obtaining large amounts of raw data, and malicious fraud immediately after version publication. This is the first time that differences in the sharing habits of users and particularly long retention time for individual files have been detected, which impact fake file detection. This paper proposes a pollution prevention model based on multiple user sharing behaviors, which reduces interference in multiple user sharing behaviors and malicious fraud immediately after version publication. It designs a low-cost implementation mechanism for use in structured peer-to-peer networks, which automatically collects a large amount of user file-sharing information and alleviates difficulties in obtaining large quantities of raw data. A parameter configuration is also given in this paper. Simulation experiments use realistic system logs and prove that this approach detects fake files accurately and quickly, thus decreasing download times of fake files, effectively guaranteeing almost 100% real file downloads and resisting file pollution.

关键词： peer-to-peer file pollution user sharing behavior

Secure multi-party computation solution to Yao's millionaires' problem based on set-inclusion

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progress in Natural science:Materials International 2005年第9期15卷 851-856页

作者： LI Shundong**, DAI Yiqi and YOU Qiyou(department of computer science and technology, Tsinghua university, beijing 100084, china) department of computer science and technology Tsinghua University Beijing 100084 China

Secure multi-party computation is a focus of international cryptography in recent years. protocols for Yao’s millionaires’ problem have become an important building block of many secure multi-party computation protocols. Their efficiency are crucial to the efficiency of many secure multi-party computation protocols. Unfortunately, known protocols for Yao’s millionaires’ problem have high computational complexity or communication complexity. In this study, based on the 1-out-of-m oblivious transfer and set-inclusion problem, we propose a new protocol to solve this problem. This new protocol is very efficient in terms of both computational and communication complexities. Its privacy-preserving property is also proved by simulation paradigm which is generally accepted in the study of secure multi-party computation. We also compare the information leakage of our new protocol and the known protocols.

关键词： secure multi-party computation Yao’s millionaires’ problem 1-out-of-m oblivious transfer set-inclusion problem.

A verifiable low-level concurrent programming model based on colored petri nets

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science china(Information sciences) 2011年第10期54卷 2013-2027页

作者： WANG ShengYuan & DONG Yuan department of computer science and technology,Tsinghua university,beijing 100084,china department of computer science and technology Tsinghua University

Concurrent programs written in a machine-level language are being used in many areas,but the verification of such programs brings various new challenges to the programming language *** of existing contributions on verifying the safety properties of concurrent programs are for high-level languages,specifications,or calculi in the *** to the lack of abstraction at a low level,additional work is needed to extend these methods to machine-level *** paper describes an approach to integrate petri nets into low-level concurrent programs to form a new programming model (abstract machine).A program in the programming model is a restricted version of colored petri net,with transitions colored by assembly codes for machine-level threads,and places colored by shared data consisting of memory locations or *** analysis and verification approaches for usual petri nets can be applied indirectly for such a low-level concurrent program.

关键词： low-level concurrent programs colored petri nets abstract machine verification

Technical framework for Internetware: An architecture centric approach

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science in china(Series F) 2008年第6期51卷 610-622页

作者： YANG FuQing1,2, Lü Jian3,4 & MEI Hong1,2 1 Key Laboratory of High Confidence Software Technologies (p.king university), Ministry of Education, beijing 100871, china 2 School of Electronics Engineering and computer science, p.king university, beijing 100871, china 3 State Key Laboratory for Novel Software technology, Nanjing 210093, china 4 department of computer science and technology, Nanjing university, Nanjing 210093, china Key Laboratory of High Confidence Software Technologies (p.king university) Ministry of Education School of Electronics Engineering and computer science Peking University State Key Laboratory for Novel Software technology department of computer Scien

Being a new software paradigm evolved by the Internet, Internetware brings many challenges to the traditional software methods and techniques. Sponsored by the national basic research program （973）, researchers in china have developed an architecture centric technical framework for the definition, incarnation and engineering of Internetware. First of all, a software model for Internetware is defined for what to be, including that Internetware entities should be packaged as components, behaving as agents, interoperating as services, collaborating in a structured and on demand manner, etc. Secondly, a middleware for Internetware is designed and implemented for how to be, including that Internetware entities are incarnated by runtime containers, structured collaborations are enabled by runtime software architecture, Internetware can be managed in a reflective and autonomic manner, etc. Thirdly, an engineering methodology for Internetware is proposed for how to do, including the way to develop Internetware entities and their collaborations by transforming and refining a set of software architectures which cover all the phases of software lifecycle, the way to identify and organize the disordered software assets by domain modeling, etc.

关键词： Internetware component software architecture agent middleware