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Research on user-aware QoS based Web services composition

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The Journal of china Universities of posts and telecommunications 2009年第5期16卷 125-130页

作者： LIU Feng , LEI Zhen-ming Key Laboratory of Information Processing and Intelligent Technology, beijing university of posts and telecommunications, beijing 100876, china Key Laboratory of Information Processing and Intelligent Technology Beijing University of Posts and Telecommunications Beijing 100876 China

To improve user experience of composite Web services, a user-aware quality of service （QoS） based Web services composition model is proposed. Under such model, a Web services selection method based on quantum genetic algorithm is proposed. This algorithm uses quantum bit encoding, dynamic step-length quantum gate angle adjustment, neighborhood service search and dynamic punishment strategy to expand search scope and speed up convergence. Simulation experiment shows that this algorithm is more efficient than other existing algorithms in Web services selection.

关键词： Web services composition user awareness quality of service quantum genetic algorithm

Resource scheduling scheme with QoS support in two-hop relay-enhanced OFDMA systems

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The Journal of china Universities of posts and telecommunications 2010年第4期17卷 26-30页

作者： LIU Wei ,JI Hong,LI Ting School of Information and Telecommunication Engineering,beijing university of posts and telecommunications,beijing 100876,china School of Information and Telecommunication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

As the system performance is obviously improved by introducing the concept of relay into the traditional orthogonal frequency division multiple access （OFDMA） systems, resource scheduling in relay-enhanced OFDMA systems is worthy of being studied carefully. To solve the optimization problem of achieving the maximum throughput while satisfying the quality of service （QoS） and guaranteeing the fairness of users, a novel resource scheduling scheme with QoS support for the downlink of two-hop relay-enhanced OFDMA systems is proposed. The proposed scheme, which is considered both in the first time sub-slot between direct link users and relay stations, and the second time sub-slot among relay link users, takes QoS support into consideration, as well as the system throughput and the fairness for users. Simulation results show that the proposed scheme has good performance in maximizing system throughput and guaranteeing the performance in the service delay and the data loss rate.

关键词： relay OFDMA QoS resource scheduling

Generalized quantum state sharing of the arbitrary two particles state

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Science china(Physics,Mechanics & Astronomy) 2010年第11期53卷 2064-2068页

作者： WANG Chuan 1,2,ZHANG Yong 1,2 & JIN GuangSheng 1,2 1 School of Science,beijing university of posts and telecommunications,beijing 100876,china 2 Key Laboratory of Optical Communication and Lightwave Technologies,beijing university of posts and telecommunications,beijing 100876,china School of Science Beijing University of Posts and Telecommunications Beijing China Key Laboratory of Optical Communication and Lightwave Technologies Beijing University of Posts and Telecommunications Beijing China

This paper has proposed a generalized quantum state sharing protocol of an arbitrary two-particle state using non-maximally GHZ states and generalized Bell state *** sender Alice performs two-particle generalized Bell state measurements on her two particles in the state sharing process and the controller takes measurements on his particles and transfers the quantum information to the receiver with entanglement swapping by the cooperation of the other *** is found that the use of nonmaximally entangled state in quantum state sharing has enabled the secure sharing of the quantum state.

关键词： quantum state sharing quantum entanglement arbitrary two particles state

Novel THP algorithms with minimum BER criterion for MIMO broadcast communications

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The Journal of china Universities of posts and telecommunications 2009年第4期16卷 71-77页

作者： YUN Xiang,L Tie-jun School of Information and Communication Engineering,beijing university of posts and telecommunications,beijing 100876,china School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

In this article, two novel Tomlinson-Harashima precoding （THP） algorithms are proposed at the downlink broadcast channel of multi-user multiple-input multiple-output （MIMO） systems. The optimality criterion is the minimization of the bit error rate （BER） at the receiver with a constraint on the overall transmitted power. In these algorithms, transmit power allocation （TPA） matrix is introduced to the traditional THP algorithms as part of the precoding matrix. This leads to a power loading operation based on substreams signal to interference-plus-noise ratio （SINR） and results in improvement of the error rate performance compared with traditional THP algorithms. When the precoding loss factor is considered, further performance improvement is achieved by the enhanced algorithm.

关键词： MIMO system THP minimum bit-error rate (MBER) broadcast communication

Threshold quantum secure direct communication without entanglement

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Science china(Physics,Mechanics & Astronomy) 2008年第2期51卷 176-183页

作者： YANG YuGuang1,3 & WEN QiaoYan2 1 College of Computer Science and Technology, beijing university of Technology, beijing 100022, china 2 School of Science, beijing university of posts and telecommunications, beijing 100876, china 3 State Key Laboratory of Information Security (Graduate School of Chinese Academy of Sciences), beijing 100049, china College of Computer Science and Technology Beijing University of Technology Beijing China State Key Laboratory of Information Security (Graduate School of Chinese Academy of Sciences) Beijing China School of Science Beijing University of Posts and Telecommunications Beijing China

For the first time, a threshold quantum secure direct communication (TQSDC) scheme is presented. Similar to the classical Shamir's secret sharing scheme, the sender makes n shares, S1, …, Sn of secret key K and each receiver keeps a share secretly. If the sender wants to send a secret message M to the receivers, he en-codes the information of K and M on a single photon sequence and sends it to one of the receivers. According to the secret shares, the t receivers sequentially per-form the corresponding unitary operations on the single photon sequence and ob-tain the secret message M. The shared shares may be reusable if it can be judged that there is no eavesdropper in line. We discuss that our protocol is feasible with current technology.

关键词： quantum secure direct communication threshold secure direct communication quantum secret sharing

QoS-guaranteed multi-relay selection and power allocation optimization in cooperative systems

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The Journal of china Universities of posts and telecommunications 2010年第6期17卷 25-31页

作者： CHEN Dan,JI Hong,LI Xi,LI Yi College of Information and Communication Engineering,beijing university of posts and telecommunications,beijing 100876,china College of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

This paper investigates the relay selection and power allocation problem in multi-user based cooperative networks,where intermediate relay nodes help source forward information to destination using decode-and-forward （DF） relaying protocol. Specifically,we propose a novel multi-relay nodes selection strategy taking both instantaneous channel state information （I-CSI） and residual energy into consideration,by which ＇emergence＇ diversity gain can be achieved and the imbalance of resource utilization can be overcome. Besides,using Largangian dual-primal decomposition and subgradient projection approach,an optimal power allocation algorithm at source and cooperative relay nodes is presented with the constraints of each user＇s individual quality of service （QoS） requirements and system total transmit power. Theoretical analysis and simulation results demonstrate that the proposed scheme can significantly improve energy efficiency,while guaranteeing a good balance between achievable data rate and average network lifetime with relatively low implementation complexity.

关键词： cooperative diversity relay selection resource allocation Lagrangian dual-primal decomposition subgradient projection

Couple Subscriber Cooperative Relaying Networks for Uplink Transmission using Hierarchical Game Approach

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china Communications 2010年第2期7卷 17-31页

作者： Song Mei, Teng Yinglei, Niu Fang, Zhang Yong, Wang Li beijing university of posts and telecommunications, beijing 100876, P.R. china beijing university of posts and telecommunications Beijing 100876 China

Cooperation allows wireless network users to benefi t from various gains such as an increase in the achieved rate or an improvement in the bit error rate. In the paper, we propose a distributed Hierarchical Game (HG) theoretic frame-work over multi-user cooperative communication networks to stimulate cooperation and improve the network performance. First, we study a two-user decision making game in the OFDMA based subscriber cooperative relaying network, in which subscribers transmit their own data in the first phase, while helping to retransmit their partner’s or choosing to freeride in the second phase. Instead of consulting to a global optimal solution, we decouple the cooperation resource allocation into two level subproblems: a user level Nash game for distributed cooperation decision and a Base Station (BS) level coalition game for centralized resource allocation. In the proposed HG algorithm, where mutual cooperation is preferred and total payoff is transferable, we prove it converges to a unique optimal equilibrium and resolve the subcarrier assignment and power allocation among the couples. Besides, we discuss the existence of the publishing and rewarding coefficients in order to encourage cooperation. Then, we extend the HG to multi-user cases by coupling among subscribers according to the location information. The simulation results show that the proposed scheme with the distributed HG game achieves a well tradeoff between fairness and effi ciency by improving the transmission effi ciency of adverse users and outperforms those employing centralized schemes.

关键词： cooperative relay hierachical game infrastructure relay subscriber relay Nash Equilibrium

Robust L2-L∞ control for uncertain singular systems with time-varying delay

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Progress in Natural Science:Materials International 2008年第8期18卷 1015-1021页

作者： Lin Lia,*, Yingmin Jiaa, Junping Dub, Shiying Yuan c a The Seventh Research Division, beijing university, beijing 100083, china b beijing Key Laboratory of Intelligent telecommunications Software and Multimedia, beijing university of posts and telecommunications, beijing 100876, china c School of Electrical Engineering and Automation, Henan Polytechnic university, Jiaozuo 454000, china The Seventh Research Division Beijing University Beijing 100083 China beijing Key Laboratory of Intelligent telecommunications Software and Multimedia Beijing University of Posts and Telecommunications Beijing 100876 China School of Electrical Engineering and Automation Henan Polytechnic University Jiaozuo 454000 China

We study the problem of L2-L1 control for a class of uncertain singular systems with time-delay and norm-bounded parameter uncertainties in this paper. A new delay-dependent robust stability criterion is obtained in terms of linear matrix inequalities (LMIs). Based on this criterion, a state feedback controller is designed to guarantee that the closed-loop system is regular, impulse free and stable with a prescribed L2-L1 performance satisfied for all admissible parameter uncertainties. A simulation example is included to illustrate the effectiveness of the proposed method.

关键词： L2–L1 control Singular systems Delay-dependent condition LMIs

Location based spectrum sensing performance analysis over fading channels in cognitive radio networks

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The Journal of china Universities of posts and telecommunications 2010年第5期17卷 26-31页

作者： YAO Hai-peng,ZHOU Zheng,SUN Xuan,LI Bin School of Information and Communication Engineering,beijing university of posts and telecommunications,beijing 100876,china School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

This paper analyzes the spectrum sensing performance over fading channel,in which a licensee and multiple unlicensed users coexist and operate in the licensed channel in a local *** overall average probabilities of detection and false alarm by jointly taking the fading and the locations of all secondary users into account are derived,and a statistical model of cumulate interference is *** on the cumulate interference,a closed-form expression of outage probability at the primary user’s receiver according to a specific distribution of the fading is ***,the sensing parameters so as to minimize the total spectrum sensing error and maximize the average opportunistic throughput are *** is noted that the overall average performance analysis and results here enable to benchmark the design of specific spectrum sensing algorithms.

关键词： spectrum sensing cognitive radio cumulate interference outage probability