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Distributed upload bandwidth assigning algorithm in P2. VoD system

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The Journal of China Universities of Posts and Telecommunications 2011年第6期18卷 78-88页

作者： DENG Guang-qing1,WEI Ting1,CHEN Chang-jia1,ZHU Wei2.WANG Bin2.WU Deng-rong2.1.School of electronic and information {2.,beijing Jiaotong University,beijing 10004.,China 2.department of PPLive P2.-CDN R&D,Shanghai 2.12.3,China School of electronic and information {2. Beijing Jiaotong University Beijing 100044 China department of PPLive P2.-CDN R&D Shanghai 201203 China

In a peer-to-peer(P2.) live streaming system,each peer uses greedy strategy to download chunks as many as possible so as to assure smooth playback and promote the chunk ***,diversity of video playback rate,heterogeneity of peer downlink bandwidth and no prefetching limitation determine that greedy strategy is not the best strategy for P2. video-on-demand(VoD) system though this strategy performs well in P2. live *** reasonably assign upload bandwidth among peers,we first present a stochastic model to relate expected downloading speed(EDS) with buffered data amount(BDA,the amount of data has been fetched in buffer,however has not been played yet by the peer),video playback rate and fluency(the probability of no interruption in a viewing process).On the base of this model,we design an equal fluency bandwidth assigning algorithm(EFBAA).In this algorithm,requesting peers compute EDS according to several local parameters(such as BDA,video playback rate and fluency) dynamically and independently and send the EDS to neighbor peers together with buffer *** the neighbor peer proportionally partitions and assigns its upload bandwidth to requesting peers according to their *** simulations demonstrate that EFBAA outperforms greedy strategy in terms of server load and startup latency.

关键词： P2. VoD fluency bandwidth quality of service(QoS)

Java Cryptography Architecture and information Security

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International Journal of Systems and Control

International Journal of Systems and Control 2008年第2期 111-120页

作者： SHEN Guicheng1,2. ZHENG Xuefeng1 1. School of information engineering, {2. University of Science and Technology, {2., {4., China 2. School of information, {2. Wuzi University, {2., 10114., China

In this paper, the security of electronic Commerce and the security methods are introduced firstly. Then, the history of Java Security Architecture and its design principles are described. After that, partial implementation of Elliptic Curve Cryptosystem developed with Java is discussed. In the end, the advantages of electronic Commerce Systems developed with Java language and Java Security Architecture are displayed.

关键词： information Security public-key Cryptography Java Security Architecture Elliptic Curve Cryptography

Estimation of wall parameters based on range profiles

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Science China(information Sciences) 2011年第10期54卷 2178-2189页

作者： LI Xin 1 ,AN DaoXiang 1,HUANG XiaoTao 1 & PENG ShiRui 2.1 college of electronic Science and {2.,National Uniersity of Defense Technology,Changsha 4.0073,China 2.department of {4. Counter Measurement Airforce Radar Academy,Wuhan 4.0019,China college of electronic Science and {2. National Uniersity of Defense Technology Changsha China department of information Counter Measurement Airforce Radar Academy Wuhan China

Compensation of wall effects is of main concern in SAR through-wall *** parameters are essential for the compensation,which are normally not known a priori.A model of SAR working in sidelooking strip mode for through-wall imaging is established,with the path of signal due to refraction taken into *** analyzing the echo configuration in time domain,a new procedure for estimating wall parameters using high range resolution profiles is *** extracting time delay of target counterpart,the thickness and permittivity of wall are figured out exactly by employing numerical equation method and intersecting of searching *** the estimated parameters,focused image of targets in a room is acquired after wall effects are compensated in imaging processing with back projection *** results verify the validity of the theoretical analysis and imaging algorithm.

关键词： synthetic aperture radar (SAR) range profiles parameters estimation wall compensation

Reverse reconciliation for continuous variable quantum key distribution

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Science China(Physics,Mechanics & Astronomy) 2010年第1期53卷 100-105页

作者： LU ZhiXin 1,2., YU Li 1,2., LI Kang 1,2., LIU BingCan 1,2.3 , LIN JianGui 1,2., JIAO RongZhen 1,2.& YANG BoJun 1,2. School of Science, beijing University of Posts and Telecommunications, beijing 100876, China 2.Key Laboratory of {2. Photonics and Optical Communication, Ministry of Education, beijing University of Posts and Telecommunications, beijing 100876, China 3 department of Fundamental Courses, Academy of Armored Force engineering, beijing 100072. China School of Science Beijing University of Posts and Telecommunications Beijing China Key Laboratory of information Photonics and Optical Communication Ministry of Education Beijing University of Posts and Telecommunications Beijing China department of Fundamental Courses Academy of Armored Force Engineering Beijing China

An efficient and practical post-processing technique based on reverse reconciliation for continuous variable quantum key distribution is proposed and simulated with low-density parity check (LDPC) codes. MultiLevel Coding/ MultiStage Decoding, which fully utilizes optimization technique such as vector quantization and iterative decoding and the optimal channel coding most close to the Shannon limit, was used to realize efficient reverse reconciliation algorithm. Simulation results showed that the proposed method can improve the secure key distribution rate to 2.2.kb/s and the coding efficiency to 0.89 over 2. km in single-mode optical fiber. Moreover, there still is room for much improvement.

关键词： quantum communication key distribution reverses reconciliation low-density parity check codes

New concurrent digital signature scheme based on the computational Diffie-Hellman problem

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The Journal of China Universities of Posts and Telecommunications 2010年第6期17卷 89-94,100页

作者： QIN Wen,ZHOU Nan-run department of electronic {2. engineering,Nanchang University,Nanchang 330031,China department of electronic {2. engineering Nanchang University Nanchang 330031 China

Based on strong designated verifiers signatures,a new fair concurrent signature scheme is proposed. Compared with the previous concurrent signature schemes,even if a keystone must be chosen by the initial signer,the matching signer will easily get the keystone through an extraction algorithm. Due to the property of strong designate verifying,the initial signer couldn＇t make use of the keystone prepared carefully to deceive the matching signer. Then the matching signer is able to participate actively the signature scheme. Besides,there aren＇t bilinear operations in the keystone algorithm to deliver the keystone efficiently. Therefore the efficiency of our signature scheme is also improved.

关键词： designated verifiers signature fairness concurrent signature information security

Statistical approach to weak signal detection and estimation using Duffing chaotic oscillators

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Science China(information Sciences) 2011年第11期54卷 2324-2337页

作者： JIN Tian & ZHANG Hua School of electronic information {2.,BeiHang University,beijing 100191,China School of electronic information {2. BeiHang University Beijing China

In this paper,we describe the statistical characteristics of weak signal detection by a chaotic Duffing oscillator,and present a new method for signal detection and estimation using the largest Lyapunov *** research has shown that weak signals can be detected by a chaotic *** researchers use the Lyapunov exponent to flag the detection of a chaotic state,but our research shows that the Lyapunov exponent follows statistical characteristics,and therefore more factors should be considered in flagging chaotic weak ***,we analyze the statistical characteristics inherent in the Lyapunov exponent calculation steps,and build up a statistical model for different chaotic states based on simulation ***,we provide expressions for false-alarm and detection probabilities,selection of driving force threshold and detection of ***,we summarize the method of signal amplitude *** research indicates that the performance of the detection system is related to sampling times and intervals,in accord with the theory of statistical signal detection.

关键词： weak signal detection Lyapunov exponent chaos Duffing oscillation statistical signal process

Influence of modulation ratio on structure and properties of nanoscale ZrB_2.ZrAlN multilayered coatings

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Science China(Technological Sciences) 2010年第3期53卷 772-775页

作者： LI DeJun 1,KANG YuanBin 1,DONG Lei 1,DENG XiangYun 1,LIU Hao 2.&SUN XueLiang 2.1college of Physics and electronic {2. Science,Tianjin Normal University,Tianjin 300387,China 2.department of Mechanical&Materials {4.,University of Western Ontario,London ON,Canada college of Physics and electronic {2. Science Tianjin Normal University Tianjin China department of Mechanical & Materials engineering University of Western Ontario London Canada

ZrB2.ZrAlN multilayered coatings with various modulation ratios(t ZrB2.t ZrAlN)and constant modulation periods were prepared by magnetron sputtering system at room ***,XRD,surface profiler and nano-indenter were employed to investigate the influences of tZ rB 2.tZrAlNon the microstructure and mechanical properties of the *** interfaces and nanoscale multilayered modulation were confirmed by *** multilayer with modulation period of 4. nm and ratio of 3:1 displayed the highest hardness(36.4.GPa)and critical fracture load(76.4.7 mN)with lower *** polycrystalline structure and multilayered modulate structure were directly responsible for the enhanced mechanical properties.

关键词： ZrB2.ZrAlN multilayered coating magnetron sputtering modulation ratio nanoscale

Pointwise estimates for the maximal multilinear singular integral operators

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Science China Mathematics 2005年第12期48卷 1696-1706页

作者： HU Guo’en, LI Dengfeng & LU Shanzhen department of Applied Mathematics, University of information {2., P. O. Box 1001 -74., Zhengzhou 4.0002. China college of Mathematical and information Sciences, Henan University, Kaifeng 4.5001, China department of Mathematics, beijing Normal University, beijing 100875, China department of Applied Mathematics University of Information Engineering Zhengzhou 450002 China college of Mathematical and information Sciences Henan University Kaifeng 475001 China department of Mathematics Beijing Normal University Beijing 100875 China

Two pointwise estimates relating the maximal multilinear singular integral operators and some classical maximal operators are established. These pointwise estimates imply the rearrangement estimate and the BLO(Rn) est... 详细信息

关键词： multilinear singular integral,maximal operator,BMO (Rn),BLO (Rn).

Analysis of forest backscattering characteristics based on polarization coherence tomography

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Science China(Technological Sciences) 2010年第S1期53卷 166-175页

作者： LUO HuanMin 1,LI XiaoWen 1,2.CHEN ErXue 3,CHENG Jian 4.& CAO ChunXiang 2. Institute of Geo-Spatial information Science and Technology,University of {2. Science and Technology of China,Chengdu 610054.China 2.State Key Laboratory of Remote Sensing Science,Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and {2. Normal University,{2. 100101,China 3Institute of Forest Resources information Technique of Chinese Academy of Forestry,{2. 100091,China 4.School of {2. engineering,University of {2. Science and Technology of China,Chengdu 610054.China Institute of Geo-Spatial information Science and Technology University of Electronic Science and Technology of China Chengdu China State Key Laboratory of Remote Sensing Science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing China Institute of Forest Resources information Technique of Chinese Academy of Forestry Beijing China School of electronic engineering University of Electronic Science and Technology of China Chengdu China

It is difficult to make an inventory of vertical profiles of forest structure parameters in field ***,analysis and understanding of forest backscattering characteristics contribute to estimation and detection of forest vertical structure because of the close relationships between backscattering characteristics and structure *** vertical structure function in the complex interferometric coherence definition,which represents the vertical variation of microwave scattering with the penetration depth at a point in the 2.D radar image and can be used to analyze the forest backscattering characteristics,can be reconstructed from polarization coherence tomography(PCT).Based on PCT,the paper analyzes the forest backscattering characteristics and explores the inherent relationship between the result of PCT and the forest structure parameters from numerical simulation of Random Volume over Ground model(RVoG),Polarimetric SAR interferometry(PolInSAR)simulation of forest scene and PolInSAR data at L-band of the test site ***,the effects of the extinction coefficient and surface-to-volume scattering ratio in RVoG model on vertical backscattering characteristics are analyzed by means of numerical ***,by applying PCT to L-band POLInSAR simulations of forest scene,different variations of vertical backscattering due to different extinction coefficients and the ratios of surface-to-volume scattering resulting from different polarizations,forest types and densities are displayed and *** a concept of relative average backscattering intensity is presented,and the factors which affect its vertical distribution are also *** results show that there is high sensitivity of the vertical distribution of forest relative average backscattering intensity to the polarization,forest type and ***,based on repeat pass DLR E-SAR L-band airborne POLInSAR data,the capability of PCT technology for detection

关键词： backscattering characteristic POLInSAR PCT vertical structure function