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An introduction to tsinghua Cloud

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

作者： ZHENG WeiMin1,2 1department of computer science and technology, tsinghua university, beijing 100084, china 2tsinghua National Laboratory for Information science and technology, beijing 100084, china 1. department of computer science and technology 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

A secure multi-party computation solution to intersection problems of sets and rectangles

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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 technology, beijing Normal university, beijing 100875, china department of computer science and technology, tsinghua university, beijing 100084, china) [a]department of computer science and technology Beijing Normal University Beijing China [b]department of computer science and technology 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.

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 1. department of computer science and technology 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

A user-space file system for on-demand legacy desktop software

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science china(Information sciences) 2011年第6期54卷 1142-1150页

作者： ZHANG YouHui 1,2 , SU GeLin 1,2 & ZHENG WeiMin 1,2 1 department of computer science and technology, tsinghua university, beijing 100084, china 2 tsinghua National Laboratory for Information science and technology, tsinghua university, beijing 100084, china 1. department of computer science and technology Tsinghua University Beijing 100084 China2. Tsinghua National Laboratory for Information Science and Technology Tsinghua University Beijing 100084 China

Some user-level virtualization technologies have been used to convert legacy software (like the existing Windows desktop applications) into the on-demand software without any modification. To give the client a friendly and compatible method to access on-demand legacy software across the Internet, this paper presents a clientend file system for this usage case. It is a Windows user-space file system based on the cloud storage (where the on-demand software is stored), which converts the local file system accesses into remote visits. Quite a few optimizations are adopted and adjusted to suit the file-access-pattern of on-demand software, including the local cache, metadata/data/software prefetch and content-addressable storage (CAS), to decrease the number of remote visits and/or to overlap IO (input/output) operations with software execution. Detailed access-pattern analyses are also presented. This file system has been implemented and tests show that it is practical for much daily-used software-a local cache of limited size can provide up to 80% hit ratio and the corresponding overhead of running-time is about 37%. Owing to this method, on any compatible and networked computer, a user can use his/her personalized software conveniently although it does not exist on the local host.

关键词： on-demand software software as a service user-space file system cloud storage

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) 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

维普期刊数据库

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

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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 technology,tsinghua university,beijing 100084.china 2 department of computer science and technology,tsinghua university,beijing 100084.china 3 Network Research Center,tsinghua university,beijing 100084.china 1. tsinghua National Laboratory for Information science and technology Tsinghua University Beijing 100084 China 2. department of computer science and technology 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

维普期刊数据库

CUDA-Zero:a framework for porting shared memory GPU applications to multi-GPUs

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science china(Information sciences) 2012年第3期55卷 663-676页

作者： CHEN DeHao , CHEN WenGuang & ZHENG WeiMin department of computer science and technology, tsinghua university, beijing 100084, china 1. department of computer science and technology Tsinghua University Beijing 100084 China

As the prevalence of general purpose computations on GPU, shared memory programming models were proposed to ease the pain of GPU programming. However, with the demanding needs of more intensive workloads, it’s desirable to port GPU programs to more scalable distributed memory environment, such as multi-GPUs. To achieve this, programs need to be re-written with mixed programming models (e.g. CUDA and message passing). Programmers not only need to work carefully on workload distribution, but also on scheduling mechanisms to ensure the efficiency of the execution. In this paper, we studied the possibilities of automating the process of parallelization to multi-GPUs. Starting from a GPU program written in shared memory model, our framework analyzes the access patterns of arrays in kernel functions to derive the data partition schemes. To acquire the access pattern, we proposed a 3-tiers approach: static analysis, profile based analysis and user annotation. Experiments show that most access patterns can be derived correctly by the first two tiers, which means that zero efforts are needed to port an existing application to distributed memory environment. We use our framework to parallelize several applications, and show that for certain kinds of applications, CUDA-Zero can achieve efficient parallelization in multi-GPU environment.

关键词： CUDA parallelization data access pattern multi-GPU

Fuzzy tracking control design for hypersonic vehicles via T-S model

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science china(Information sciences) 2011年第3期54卷 521-528页

作者： GAO DaoXiang 1 & SUN ZengQi 2 1 School of technology, beijing Forestry university, beijing 100083, china 2 State Key Laboratory of Intelligent technology and System, department of computer science and technology, tsinghua university, beijing 100084, china 1. School of technology Beijing Forestry University Beijing 100083 China2. State Key Laboratory of Intelligent Technology and System Department of Computer Science and Technology Tsinghua University Beijing 100084 China

The main focus of this paper is on designing a T-S fuzzy controller for the hypersonic vehicle. The longitudinal dynamics of the vehicle are studied using time-scale decomposition to reduce the complexity of T-S modeling. The dynamic inversion with PI control technique is applied for the slow dynamics to derive the flight path angle command and throttle setting by taking the pilot altitude and velocity command as its inputs. The T-S fuzzy controller is designed for the fast dynamics to derive the elevator deflection to track the flight path angle command. The discrepancy between the T-S model and real vehicle model is considered by using sliding mode control for the system stability. Simulation results are included to show the effectiveness of the controller.

关键词： fuzzy control T-S model sliding mode control hypersonic vehicle