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Data-aided synchronization algorithm dispensing with searching procedures for UWB communications

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science China(Information sciences) 2012年第4期55卷 778-788页

作者： REN ZhiYuan 1,JIANG Ting1,ZHONG Yi 2.& ZHAO ChengLin 1 1 Key Laboratory of Universal Wireless Communications,Ministry of Education of China Wireless Network Laboratory,beijing university of {2. and telecommunications,beijing 100876,China 2.school of Information Engineering,North China university of Technology,beijing 100041,China Key Laboratory of Universal Wireless Communications Ministry of Education of China Wireless Network Laboratory Beijing University of Posts and Telecommunications Beijing China school of Information Engineering North China University of Technology Beijing China

Rapid and accurate synchronization constitutes a major challenge in deploying Ultra-Wideband impulse radio (UWB-IR) for indoor wireless *** paper develops a data-aided (DA) synchro-nization algorithm dispensing with searching procedures for UWB-IR *** adopting a stream of alternating orthogonal pulses,frame-level synchronization can be achieved without channel ***-out utilizing any searching procedure,the timing offset estimator is obtained in a closed *** exhaustive search can be avoided,both computational complexity and synchronization time are *** and comparisons are provided to illustrate the advantages of our design over the alternatives.

关键词： Ultra-Wideband impulse radio synchronization dispensing with searching procedures searching space data-aided estimation

Improved discriminative training for generative model

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The Journal of China Universities of posts and telecommunications 2009年第3期16卷 126-130页

作者： WU Ya-hui,GUO Jun,LIU Gang Laboratory of Pattern Recognition and Intelligent System,beijing university of {2. and telecommunications,beijing 100876,China Laboratory of Pattern Recognition and Intelligent System Beijing University of Posts and Telecommunications Beijing 100876 China

This article proposes a model combination method to enhance the discriminability of the generative model. Generative and discriminative models have different optimization objectives and have their own advantages and drawbacks. The method proposed in this article intends to strike a balance between the two models mentioned above. It extracts the discriminative parameter from the generative model and generates a new model based on a multi-model combination. The weight for combining is determined by the ratio of the inter-variance to the intra-variance of the classes. The higher the ratio is, the greater the weight is, and the more discriminative the model will be. Experiments on speech recognition demonstrate that the performance of the new model outperforms the model trained with the traditional generative method.

关键词： model combination discriminability generative model training speech recognition

Hopping control channel MAC protocol for opportunistic spectrum access networks

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The Journal of China Universities of posts and telecommunications 2010年第6期17卷 65-71页

作者： FU Jing-tuan,JI Hong,MAO Xu Key Laboratory of Universal Wireless Communications,Ministry of Education,beijing university of {2. and telecommunications,beijing 100876,China Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

Opportunistic spectrum access （OSA） is considered as a promising approach to mitigate spectrum scarcity by allowing unlicensed users to exploit spectrum opportunities in licensed frequency bands. Derived from the existing channel-hopping multiple access （CHMA） protocol,we introduce a hopping control channel medium access control （MAC） protocol in the context of OSA networks. In our proposed protocol,all nodes in the network follow a common channel-hopping sequence; every frequency channel can be used as control channel and data channel. Considering primary users＇ occupancy of the channel,we use a primary user （PU） detection model to calculate the channel availability for unlicensed users＇ access. Then,a discrete Markov chain analytical model is applied to describe the channel states and deduce the system throughput. Through simulation,we present numerical results to demonstrate the throughput performance of our protocol and thus validate our work.

关键词： channel hopping MAC protocol OSA Markov chain

Network parameters awareness for routing discovery in autonomic optical Internet

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The Journal of China Universities of posts and telecommunications 2009年第2期16卷 84-88,128页

作者： JIN Jin WANG Hong-xiang JI Yue-feng Key Laboratory of Optical Communication and Lightwave Technologies,beijing university of {2. and telecommunications,beijing 100876,China Key Laboratory of Optical Communication and Lightwave Technologies Beijing University of Posts and Telecommunications Beijing 100876 China

The article proposes a network parameter-awareness （NPA） method and applies it to routing discovery algorithms in autonomic optical Internet. This NPA method can perceive the main parameters of the network, such as delay, jitter and traffic, which can represent the current situation of the network. And these parameters enable network to determine the appropriate nodes for routing discovery. The simulation results of evaluating performance of a network with NPA method and its routing applications show that the method and its applications in routing improve the performance of the network significantly with quality of service （QoS） guaranteed.

关键词： NPA autonomic optical Internet self-aware muting QoS

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

Bandwidth allocation and admission control scheme based on Nash bargaining solution for WiMAX systems

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The Journal of China Universities of posts and telecommunications 2010年第2期17卷 53-58页

作者： CAI Dao-jin ,JI Hong,LI Xi Key Laboratory of Universal Wireless Communications,Ministry of Education,beijing university of {2. and telecommunications,beijing 100876,China Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

Development of fair and efficient bandwidth allocation and admission control schemes is one of the key issues in the design of IEEE 802.16 broadband wireless access systems in time division multiple access （TDMA） mode. In this article, the problem of bandwidth allocation and admission control is formulated as a Nash bargaining model. The nash bargaining solution （NBS） derived from the cooperative game is adopted to maximize the spectrum utilization. Analysis and simulation results show that there is a unique Pareto optimal bandwidth allocation solution by using NBS among various flows. Furthermore, maximum utility of the system can also be maintained by using the admission control policy with different number of connections and variable channel qualities. The total throughput of the proposed scheme is close to the maximal one, while significantly improving fairness compared to the existing solutions.

关键词： NBS game theory bandwidth allocation admission control IEEE 802.16

Symbolic Computation Study of (2.1)-Dimensional Dispersive Long Wave Equations

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Communications in Theoretical Physics 2006年第8期46卷 199-202页

作者： LU Zhuo-Sheng~(1,2.+) and XIE Fu-Ding~(2.3) ~1school of science, {2. university of Post and telecommunications, beijing 100876, China ~2.ey Laboratory of Mathematics Mechanization, Academy of Mathematics and System sciences, the Chinese Academy of sciences, {2. 100080, China ~3Department of Computer science, Liaoning Normal university, Dalian 11602., China school of science Beijing University of Post and Telecommunications Beijing 100876 China Key Laboratory of Mathematics Mechanization Academy of Mathematics and System Sciences the Chinese Academy of Sciences Beijing 100080 China Department of Computer science Liaoning Normal University Dalian 116029 China

Seeking exact analytical solutions of nonlinear evolution equations is of fundamental importance in mathematical physics. In this paper, based on a constructive algorithm and symbolic computation, abundant new exact solutions of the (2.1)-dimensional dispersive long wave equations are obtained, among which there are soliton-like solutions, mult-soliton-like solutions and formal periodic solutions, etc. Certain special solutions are considered and some interesting localized structures are revealed.

关键词： dispersive long wave equations symbolic computation exact solution localized structure

Automatic composition of information-providing web services based on query rewriting

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science China(Information sciences) 2012年第11期55卷 2428-2444页

作者： ZHAO WenFeng,LIU ChuanChang & CHEN JunLiang State Key Laboratory of Networking and Switching Technology,beijing university of {2. and telecommunications,beijing 100876,China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing China

Compared with normal web services,information-providing services have unique features that have seldom been considered in existing research on the automatic composition of web *** this paper,we present a simple,yet well-formed,semantic-based capability model for information-providing web services,which can express such features as not modifying the world state and not requiring all input/output parameters to be supplemented with class information as *** then present a corresponding automatic composition method derived from a query rewriting algorithm,MiniCon,used in the data integration *** method adequately utilizes previous features,enables primitive semantic reasoning,and can generate executable BPEL scripts *** of the method is complementary to traditional search-based *** on a typical type of problem show that the method is usable in practice.

关键词： web services automatic composition query rewriting data integration ontology semantic web

On-demand coding-aware routing in wireless Mesh networks

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The Journal of China Universities of posts and telecommunications 2010年第5期17卷 80-86,92页

作者： SUN Jian-zhen,LIU Yuan-an,HU He-fei,YUAN Dong-ming Wireless Communications and EMC Laboratory,beijing university of {2. and telecommunications,beijing 100876,China Wireless Communications and EMC Laboratory Beijing University of Posts and Telecommunications Beijing 100876 China

Network coding,which exploits the broadcast nature of wireless medium,is an effective way to improve network performance in wireless multi-hop networks,but the first practical wireless network coding system COPE cannot actively detect a route with more coding opportunities and limit the coding structure within two-hop *** on-demand coding-aware routing scheme （OCAR） for wireless Mesh networks is proposed to overcome the limitations specified above by actively detecting a route with more coding opportunities along the entire route rather than within two-hop *** more coding opportunities tends to route multiple flows ‘close to each other’ while avoiding interference requires routing multiple flows ‘away from each other’.OCAR achieves a tradeoff by adopting RC AIA as routing metric in route discovery,which is not only coding-aware but also considers both inter and intra flow *** results show that,compared with Ad-hoc on-demand distance vecfor routing （AODV） and AODV＋COPE,OCAR can find more coding opportunities,thus effectively increase network throughput,reduce end to end delay and alleviate network congestion.

关键词： Mesh networks network coding coding-aware routing protocol