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Distributed GEP query optimization on grid service

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The Journal of China Universities of posts and telecommunications 2010年第3期17卷 118-122,128页

作者： DENG Yong, WANG Ru-chuan College of Computer, nanjing university of posts and telecommunications, nanjing 210003, China College of Computer Nanjing University of Posts and Telecommunications Nanjing 210003 China

In order to better solve the problem of distributed query optimization, a query optimization algorithm on gene expression programming （GEP）（QO-GEP） is presented. On the basis of QO-GEP, distributed GEP query optimization on grid service （DGEPQO-GS） is proposed which combines grid service. Simulated experiments show that with the increment of the number of query relation, query time which QO-GEP carries out query decreases apparently. Meanwhile, with the increase of the number of grid nodes, the average querying success rate of DGEPQO-GS increases significantly.

关键词： gene expression programming distributed query grid service query relation

QoS routing based on mobile agent for LEO satellite IP networks

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The Journal of China Universities of posts and telecommunications 2009年第6期16卷 57-63页

作者： RAO Yuan,WANG Ru-chuan College of Computer,nanjing university of posts and telecommunications,nanjing 230001,China College of Computer Nanjing University of Posts and Telecommunications Nanjing 230001 China

Current quality of service（QoS） routing schemes for low earth orbit（LEO） satellites IP networks either neglect the varying population density or fail to guarantee end-to-end *** a remedy,QoS routing protocol based on mobile agent（QoSRP-MA） is ***-MA is a source-based routing *** connection requests arrive,QoS mobile agents are dispatched from ingress satellite to explore routes,which migrate using satellite routing *** arriving in egress satellite,QoS mobile agents migrate back towards ingress satellite to reserve *** construct satellite routing tables,load balancing routing algorithm based on mobile agent（LBRA-MA） is *** LBRP-MA,at regular intervals mobile agents launched on all satellites migrate autonomously to evaluate path cost and update routing ***,path cost between source and destination is evaluated considering satellite geographical position as well as inter-satellite link（ISL） ***,ISL congestion index is considered to update routing *** simulations on a Courier-like constellation,it shows that QoSRP-MA can achieve guaranteed end-to-end delay bound with higher throughput,lower connection failing ratio and signaling overhead compared to high performance satellite routing（HPSR） scheme.

关键词： QoS routing load balancing mobile agent satellite IP networks

Structure splitting framework for data-layout optimization

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The Journal of China Universities of posts and telecommunications 2009年第5期16卷 107-113页

作者： FU Xiong , WANG Ru-chuan College of Computer, nanjing university of posts and telecommunications, nanjing 210003, China College of Computer Nanjing University of Posts and Telecommunications Nanjing 210003 China

To improve data cache performance, optimizing program data layout by data reorganization has become an important method of decreasing the impact of increasing gap of speed between processor and memory. In this article, a structure splitting framework with an analysis model named structure field relation graph （SFRG） is presented to optimize program data layout. The SFRG can be used to quantify relationship between fields. It helps to find an optimal layout for structure as well as the optimal program data layout. And the data cache performance is improved through SFRG-based structure splitting. Experiments show that this framework is effective in optimizing program data layout and improving the performance of data cache and whole program.

关键词： program optimization structure splitting data layout cache performance

Secure coverage-preserving node scheduling scheme using energy prediction for wireless sensor networks

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The Journal of China Universities of posts and telecommunications 2010年第5期17卷 100-108页

作者： LI Zhi-yuan,WANG Ru-chuan. College of Computer,nanjing university of posts and telecommunications,nanjing 210003,China College of Computer Nanjing University of Posts and Telecommunications Nanjing 210003 China

With the fast development of the micro-electro-mechanical systems （MEMS）,wireless sensor networks （WSNs） have been extensively *** of the studies focus on saving energy consumption because of restricted energy supply in ***-based node scheduling scheme is commonly considered as one of the most energy-efficient ***,it is not always so efficient especially when there exist hot spot and network attacks in *** this article,a secure coverage-preserved node scheduling scheme for WSNs based on energy prediction is proposed in an uneven deployment *** scheme is comprised of an uneven clustering algorithm based on arithmetic progression,a cover set partition algorithm based on trust and a node scheduling algorithm based on energy *** results show that network lifetime of the scheme is 350 rounds longer than that of other scheduling ***,the scheme can keep a high network coverage ratio during the network lifetime and achieve the designed objective which makes energy dissipation of most nodes in WSNs balanced.

关键词： wireless sensor networks secure energy-efficient coverage node scheduling cover set energy prediction

The influence of higher-order effects on the transmission performances of the ultra-short soliton pulses and its suppression method

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Science China(Information Sciences) 2010年第1期53卷 182-190页

作者： ZHU Bo & YANG XiangLin Institute of Optical Communication, nanjing university of posts and telecommunications, nanjing 210003, China Institute of Optical Communication Nanjing University of Posts and Telecommunications

Under the condition of the higher order effects, a propagation equation is established to investigate the way to suppress the soliton self frequency shift and timing jitter in the picosecond and femtosecond soliton communication system using a combined control method of time domain and frequency domain. By the use of the variational approach, the evolution of the chirping Gaussian quasi-soliton pulse is analyzed in the presence of the effects including third order dispersion, intrapulse Raman scattering (IRS), and self steepening. Considering the soliton evolution properties and the mechanism of the timing jitter under the higher-order effects, the combined control method is adopted to eliminate the influence from Raman scattering and self-steepening. The soliton central frequency is stabilized and the timing jitter is suppressed effectively. A 160 Gb/s long-haul soliton transmission system is designed and its performance is numerically simulated. The simulation results are in good agreement with our theoretical analysis.

关键词： high rate soliton communication higher-order nonlinearity Raman self-frequency shift transmission control stable transmission

Key technologies of new malicious code developments and defensive measures in communication networks

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The Journal of China Universities of posts and telecommunications 2010年第4期17卷 69-73页

作者： LI Peng,WANG Ru-chuan ,ZHANG Wei College of Computer,nanjing university of posts and telecommunications,nanjing 210003,China College of Computer Nanjing University of Posts and Telecommunications Nanjing 210003 China

This article is focused on analyzing the key technologies of new malicious code and corresponding defensive measures in the large-scale communication networks. Based on description of the concepts and development of the malicious code, the article introduces the anti-analysis technology, splitting and inserting technology, hiding technology, polymorph virus technology, and auto production technology of the malicious code trends with intelligence, diversity and integration. Following that, it summarizes the security vulnerabilities of communication networks from four related layers aspects, according to the mechanisms of malicious code in the communication networks. Finally, it proposes rapid response disposition of malicious code attacks from four correlated steps： building up the network node monitoring system, suspicious code feature automation analysis and extraction, rapid active malicious code response technique for unknown malicious code, and malicious code attack immunity technique. As a result, it actively defenses against the unknown malicious code attacks and enhances the security performance of communication networks.

关键词： network security malicious code network attack and defense malicious code defense

Channel estimation in space and frequency domain for MIMO-OFDM systems

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The Journal of China Universities of posts and telecommunications 2009年第3期16卷 40-44页

作者： PAN Pei-sheng,ZHENG Bao-yu College of Communication and Information,nanjing university of posts and telecommunications,nanjing 210003,China College of Communication and Information Nanjing University of Posts and Telecommunications Nanjing 210003 China

Multiple-input multiple-output （MIMO） systems can be combined with orthogonal frequency division multiplexing （OFDM） systems to improve the capacity and quality of wireless communications. In this article, a channel estimation technique in both space and frequency domain for MIMO-OFDM systems is proposed. It is shown that the proposed scheme with space-frequency pilot tones achieve optimal minimum mean square error （MMSE） channel estimation. Simulation results indicate that the proposed method achieves good performance.

关键词： channel estimation MIMO OFDM space frequency pilot tones

Present Status and Future Development of Mobile Internet

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China Communications 2009年第1期6卷 113-118页

作者： Wang Jian1, Bi Houjie2 1nanjing university, nanjing 210093, China 2nanjing university of posts and telecommunications, nanjing 210003, China nanjing university Nanjing 210093 China nanjing university of posts and telecommunications Nanjing 210003 China

With the integration of telecommunications network and Internet, mobile Internet is bound to rise. Mobile Internet brings not only high-quality business experience; but also enormous challenges to telecommunications. The current status and hierarchical structure of the mobile Internet are presented. Technological advances and market demand are promoting development of mobile Internet, and terminals, networks and businesses are three elements of the development of the mobile Internet. Mobile IP technique and related protocols are described systematically, which are designed to allow mobile terminal and the mobile sub-network to roam within the Internet. Then the IP Multimedia Subsystem (IMS) and its architectural framework are expounded, which are designed by (3GPP). The credible and reliable IP network architecture with Quality of Service (QoS) based on IMS is discussed to meet the needs of the next generation of mobile Internet. Finally, the hotspots such as P2P/ Multicast/ Security are pointed out within the mobile Internet.

关键词： Mobile Internet mobile IP IMS network convergence

Performance analysis of compact MIMO system based on network theory

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The Journal of China Universities of posts and telecommunications 2009年第6期16卷 6-10,37页

作者： XU Dan,ZHANG Jing,ZHANG Ye-rong College of Communication and Information Technology,nanjing university of posts and telecommunications,nanjing 210003,China College of Communication and Information Technology Nanjing University of Posts and Telecommunications Nanjing 210003 China

The impact of mutual coupling on the performance of multiple-input multiple-output（MIMO） systems with compact antenna arrays is *** article aims to use the S-parameter modeling approach to examine the impact of mutual coupling on three system-related performance measures：antenna correlation,efficiency and *** is shown that implementing a good matching network can drastically improve the system performance in the presence of strong mutual *** results indicate the superiority of cross-shaped antenna to dipole antenna.

关键词： MIMO mutual coupling wireless channel