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CONDITIONS FOR UNIFORMLY NON-CONFOUNDING OF CAUSal DISTRIBUTION EFFECTS OVER MULTIPLE COVARIATES

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Journal of Systems science & Complexity 2010年第4期23卷 796-803页

作者： Xueli WANG School of science,beijing university of posts and telecommunications,beijing 100876,china. School of science Beijing University of Posts and Telecommunications

Causation is a distinct concept from association and more important than association inepidemiologic *** paper proposes the concept of uniform non-confounding for causal distributioneffects over multiple covariates,and gives the sufficient conditions for uniform non-confoundingover a covariate set C including confounders or non-confounders,and also shows the conditions forconditionally non-confounding in the *** these conditions can be tested by observeddata.

关键词： Causal distribution effect confounding covariates uniform non-confounding

STABILITY OF GENERalIZED JACKSON NETWORKS WITH INFINITE SUPPLY OF WORK

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Journal of Systems science & Complexity 2008年第2期21卷 283-295页

作者： Yongjiang GUO School of science Beijing University of Posts and Telecommunications Beijing 100876 China

A general Jackson network （GJN） with infinite supply of work is considered. By fluid limit model, the author finds that the Markov process describing the dynamics of the GJN with infinite supply of work is positive Harris recurrent if the corresponding fluid model is stable. Furthermore, the author proves that the fluid model is stable if the usual traffic condition holds.

关键词： Fluid limit model general Jackson network (GJN) infinite supply positive Harris recurrent stability.

TWO-AGENT PARETO OPTIMal COOPERATIVE INVESTMENT IN INCOMPLETE MARKET:AN EQUIValENT CHARACTERIZATION

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Journal of Systems science & Complexity 2011年第4期24卷 701-710页

作者： Qing ZHOU School of science Beijing University of Posts and Telecommunications Beijing 100876 China.

This paper studies the following cooperative investment game with two agents. At the start of the game, both the agents＇ capital are collected. The total capital are then invested according to a certain trading strategy. At a certain time To one agent quits the cooperation and they divide the wealth among themselves. During the remaining period [To, T], the other agent invests his/her capital following a possibly different trading strategy. By stochastic optimization method combined with the theory of Backward Stochastic Differential Equations （BSDEs, for short）, we give an equivalent characterization of the Pareto optimal cooperative strategies.

关键词： Backward stochastic differential equation cooperative investment incomplete market,Pareto optimum stochastic utility.

SVM-based loss differentiation algorithm for wired-cum-wireless networks

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The Journal of china Universities of posts and telecommunications 2009年第4期16卷 104-111页

作者： DENG Qian-hua ,CAI An-ni School of Telecommunication Engineering,beijing university of posts and telecommunications,beijing 100876,china [a]School of Telecommunication Engineering beijing university of posts and telecommunications beijing 100876 china

In a hybrid wired-cum-wireless network environment, packet loss may happen because of congestion or wireless link errors. Therefore, differentiating the cause is important for helping transport protocols take actions to control congestion only when the loss is caused by congestion. In this article, an end-to-end loss differentiation mechanism is proposed to improve the transmission performance of transmission control protocol （TCP）-friendly rate control （TFRC） protocol. Its key design is the introduction of the outstanding machine learning algorithm - the support vector machine （SVM） into the network domain to perform multi-metric joint loss differentiation. The SVM is characterized by using end-to-end indicators for input, such as the relative one-way trip time and the inter-arrival time of packets fore-and-aft the loss, while requiring no support from intermediate network apparatus. Simulations are carried out to evaluate the loss differentiation algorithm with various network configurations, such as with different competing flows, wireless loss rate and queue size. The results show that the proposed classifier is effective under most scenarios, and that its performance is superior to the ZigZag, mBiaz and spike （ZBS） scheme.

关键词： machine learning SVM TCP-friendly rate control (TFRC) congestion control

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 1. School of science Beijing University of Posts and Telecommunications Beijing 100876 China2. Key Laboratory of Optical Communication and Lightwave Technologies Beijing University of Posts and Telecommunications Beijing 100876 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

Search recommendation model based on user search behavior and gradual forgetting collaborative filtering strategy

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The Journal of china Universities of posts and telecommunications 2010年第3期17卷 110-117页

作者： LIU Chuan-chang State Key Laboratory of Networking and Switching Technology, beijing university of posts and telecommunications, beijing 100876, china [a] State Key Laboratory of Networking Switching Technology Beijing University of Posts telecommunications Beijing 100876 China

The existing search engines are lack of the consideration of personalization and display the same search results for different users despite their differences in interesting and purpose. By analyzing user＇s dynamic search behavior, the paper introduces a new method of using a keyword query graph to express user＇s dynamic search behavior, and uses Bayesian network to construct the prior probability of keyword selection and the migration probability between keywords for each user. To reflect the dynamic changes of the user＇s preference, the paper introduces non-lineal gradual forgetting collaborative filtering strategy into the personalized search recommendation model. By calculating the similarity between each two users, the model can do the recommendation based on neighbors and be used to construct the personalized search engine.

关键词： search recommendation model search behavior expression keyword query graph gradual forgetting collaborative filtering

Novel limited feedback scheme under the MIMO broadcast system

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The Journal of china Universities of posts and telecommunications 2009年第6期16卷 11-16页

作者： CHENG Tie-zheng,YUAN Chao-wei School of Information and Communication Engineering,beijing university of posts and telecommunications,beijing 100876,china [a] School of Information and Communication Engineering beijing university of posts and telecommunications beijing 100876 china

By deducing the distribution of the normalized channel covariance matrix,a novel limited feedback scheme is proposed under multiple users（MU） multiple-input multiple-output（MIMO） broadcast channel（BC） *** proposed scheme has advantages in three ***,it has no constraints on the number of users or ***,each user＇s feedback bits are independent of the number of receiving ***,the proposed scheme avoids the storage of large-size codebook on the *** results show that the performance of the proposed scheme is close to the perfect channel state information（CSI） case and it just needs a small number of feedback bits.

关键词： MIMO broadcast channel limited feedback normalized channel covariance

Synchronization of MIMO OFDM systems by perfect complete generalized complementary orthogonal loosely synchronous code groups

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The Journal of china Universities of posts and telecommunications 2009年第2期16卷 1-7页

作者： WANG Jian YANG Xun LI Dao-ben School of Information Engineering,beijing university of posts and telecommunications,beijing 100876,china [a]School of Information Engineering beijing university of posts and telecommunications beijing 100876 china

This article proposes a time/frequency synchronization algorithm in the multiple input multiple output （MIMO） systems, in which the perfect complete generalized complementary orthogonal loosely synchronous code groups are used as the synchronization sequence. The synchronization algorithm is divided into four stages： 1） synchronization in time domain by signal autocorrelation; 2） synchronization in frequency domain by fast Fourier transform （FFT）; 3） multipath dissociation using coherent detection and fine time synchronization; 4） fine frequency offset estimation by phase rotation. As per the perfect complete generalized complementary orthogonal loosely synchronous code groups, the cross-correlation and out-of-phase auto-correlation for any relative shift between any two codes is always zero. This ideal property makes the time/frequency synchronization algorithm simple and efficient. The simulation results show that even in the multipath fast fading channel with low signal noise ratio （SNR）, the MIMO system can get synchronized both in the time domain and frequency domain with high stability and reliability.

关键词： MIMO OFDM synchronization complementary orthogonal code loosely synchronous (LS) code

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 [a]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