检索结果-南通市图书馆

Acta Metallurgica Sinica(English Letters) 1992年第9期5卷 178-182页

作者： QIAO Lijie LIU Rui XIAO Jimei university of science and technology Beijing,Beijing,{3.

The effects of stress components on nucleation sites and propagation directions of stress cor- rosion cracks in brass were investigated with specimens under mode Ⅱ and mode Ⅲ loadings. The results indicated that under mode Ⅱ loading,stress corrosion cracks nucleated on the site with maximum normal stress component and propagated along the plane perpendieular to the maximum normal stress,under mode Ⅲ loading,the stress corrosion crack was not evident on the 45°plane due to the general corrosion in aqueous solution with high NH_4OH concentra- tion,while stress corroded in aqueous solution with low NH_4OH concentration, numerous cracks with spacings of 10—150μm were found on the 45°plane with maximum normal stress and no stress corrosion cracks was observed on the plane with maximum shear stress.

关键词： stress corrosion cracking stress compoonent brass ammonia solution

Fuzzy tolerance quotient spaces and fuzzy subsets

在线全文

学校读者我要写书评

暂无评论

science china(information sciences) 2010年第4期53卷 704-714页

作者： ZHANG Ling1 & ZHANG Bo2,3.4* 1computer science & technology {3., Anhui university, Anhui 23.03., china 2State Key Laboratory of Intelligent technology and Systems, Beijing 100084, china 3.9} National Laboratory of information science & technology, Beijing 100084, china 4information science & technology college, computer science & technology department, tsinghua university, Beijing 100084, china 1. computer science & technology {3. Anhui University Anhui 230039 China2. State Key Laboratory of Intelligent Technology and Systems Beijing 100084 China3. Tsinghua National Laboratory of Information Science & Technology Beijing 100084 China4. Information Science & Technology College Computer Science & Technology Department Tsinghua University Beijing 100084 China

The structure and characteristic of fuzzy subsets are discussed by using the concepts of granulation and hierarchy in quotient space theory. First, the equivalence relation based quotient space theory is extended to the fuzzy tolerance relation. Second, the isomorphism and its discriminant of fuzzy tolerance relations are discussed. Finally, by using the fuzzy tolerance relation to define the fuzzy subset, its properties are addressed. The main results are given below: (1) several equivalent statements of fuzzy tolerance relations; (2) the definition of isomorphism of fuzzy tolerance relations; (3. the isomorphic discriminant of fuzzy tolerance relations; (4) the definition and properties of fuzzy subsets based on the fuzzy tolerance relations; and (5) the necessary and sufficient condition of the isomorphism of fuzzy subsets. These results will help us further comprehend the concepts of fuzzy tolerance relations and fuzzy subsets.

关键词： Fuzzy tolerance relation quotient space isomorphism fuzzy subset

Compactness in fuzzy logic

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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

作者： YING Mingsheng department of computer science and {3., tsinghua university, Beijing 100084, china department of computer science and {3. 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.

The structural analysis of fuzzy measures

在线全文

学校读者我要写书评

暂无评论

science china(information sciences) 2011年第1期54卷 38-50页

作者： ZHANG Ling1,ZHANG Bo2 & ZHANG YanPing1 1 computer science college,Anhui {3.,Hefei 23.03.,china 2State Key Lab of Intelligent technology & Systems tsinghua National Lab for information science & technology information science & technology college,computer science & technology,tsinghua {3.,Beijing 100084,china 1. computer science college Anhui University Hefei 230039 China2. State Key Lab of Intelligent Technology & Systems tsinghua National Lab for information science & {3. information science & technology {3. Computer Science & Technology Tsinghua University Beijing 100084 China

From quotient space based granular computing theory we explore the fuzzy measures of fuzzy sets. Based on the structural analysis of fuzzy sets,we present an"isotropism"*** this assumption we achieved the following insights:(1)the uniqueness of a fuzzy measure being isotropic on a finite complete semi-ordered set;(2)the necessary and suffcient condition of the isomorphism for fuzzy measure functions in fuzzy mathematics;(3.the necessary and suffcient condition that fuzzy measures have fuzzy and granular monotonicity;(4)under a certain assumption,the analytic expression for fuzzy *** results clarify the relationship between fuzzy measures and granular computing,reveal the essence of fuzzy measures,and provide a simple way of constructing fuzzy measures.

关键词： quotient space fuzzy set fuzzy measure rough set structural analysis

Performance Modeling and Approximate Analysis of Multiserver Multiqueue Systems with Poisson and Self-similar Arrivals

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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 {3. Beijing, Beijing 100083. china) (department of computer science and {3., tsinghua university, Beijing 100084, china) Univ Sci & Technol Beijing Informat Engn Sch Beijing 100083 Peoples R China tsinghua Univ Dept Comp Sci & Technol Beijing 100084 Peoples R 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

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

在线全文

学校读者我要写书评

暂无评论

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 {3., tsinghua university, Beijing 100084, china) department of computer science and {3. 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 secure multi-party computation solution to intersection problems of sets and rectangles

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2006年第5期16卷 538-545页

作者： LI Shundong, DAI Yiqi, WANG Daoshun and LUO Ping (department of computer science and {3., Beijing Normal university, Beijing 100875, china department of computer science and {3., tsinghua university, Beijing 100084, china) [a]department of computer science and {3. Beijing Normal University Beijing China [b]department of computer science and {3. Tsinghua University Beijing China

Secure multi-party computation (SMC) is a research focus in international cryptographic community. At present, there is no SMC solution to the intersection problem of sets. In this paper, we first propose a SMC solution to this problem. Applying Cantor encoding method to computational geometry problems, and based on the solution to set-intersection problem, we further propose solutions to points inclusion problem and intersection problem of rectangles and further prove their privacy-preserving property with widely accepted simulation paradigm. Compared with the known solutions, these new solutions are of less computational complexity and less communication complexity, and have obvious superiority in computational and communication complexity.

关键词： Cantor encoding secure multi-party computation set-intersection rectangle-intersection computational complexity.

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

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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 {3.,tsinghua university,Beijing 100084,china 1. department of computer science and {3. Tsinghua University Beijing 100084 China

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

An introduction to tsinghua Cloud

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(information sciences) 2010年第7期53卷 1481-1486页

作者： ZHENG WeiMin1,2 1department of computer science and {3., tsinghua university, Beijing 100084, china 2tsinghua National Laboratory for information science and {3., Beijing 100084, china 1. department of computer science and {3. Tsinghua University Beijing 100084 China2. Tsinghua National Laboratory for Information Science and Technology Beijing 100084 China

Cloud computing has become a trend that draws attention from both academia and industry all over the world. This paper unveils details of tsinghua Cloud, a comprehensive solution for cloud computing developed by Tsing... 详细信息

关键词： cloud computing distributed file system virtual computing environment data sharing

RRM:An incentive reputation model for promoting good behaviors in distributed systems

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science in china(Series F) 2008年第11期51卷 1871-1882页

作者： ZHANG Hong1,2,DUAN HaiXin1,3.& LIU Wu1,3.1 tsinghua National Laboratory for information science and {3.,tsinghua university,Beijing 100084,china 2 department of computer science and {3.,tsinghua university,Beijing 100084,china 3.Network Research Center,tsinghua university,Beijing 100084,china 1. tsinghua National Laboratory for information science and {3. Tsinghua University Beijing 100084 China 2. department of computer science and {3. Tsinghua University Beijing 100084 China 3. Network Research Center Tsinghua University Beijing 100084 China

Reputation systems represent soft security mechanisms that complement traditional information security mechanisms. They are now widely used in online e-commerce markets and communities in order to stimulate good behaviors as well as to restrain adverse behaviors. This paper analyzes the limitations of the conversational reputation models and proposes an incentive reputation model called the resilient reputation model （RRM） for the distributed reputation systems. The objective of this reputation model is not only to encourage the users to provide good services and, therefore, to maximize the probability of good transaction outcomes, but also to punish those adverse users who are trying to manipulate the application systems. The simulation results indicate that the proposed reputation model （RRM） could effectively resist against the common adverse behaviors, while protecting the profits of sincere users from being blemished by those adversaries.

关键词： reputation model distributed system trust soft security