Current Issue

• • 2004, Vol. 27 No. 6 Published date:28 June 2004 Last issue Next issue

  PAPERS

  • A Novel Sensor Placement Model in Wireless Sensor Network
  • QU Yu-gui, ZHAI Yu-jia, LIN Zhi-ting,ZHAO Bao-hua, ZHANG Ying-tang
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 1-5.
  • Abstract ( 235 )     HTML     　　
  • Senso r placement i s o ne of the key topics addressed in sensor netw o rks study. This pa per pro poses a nov el sensor placement model and a so-called IN T EGER LOCAL COV algo ri thm wi th a mo re ef ficient cov erag e, based o n the modeling of the node characteri stics, terrain shield and preferentia l cov erag e of g rids as tha t analy zed by Dhi llo n S. S. . In the new placement scheme, the detection limi t of senso rs i s al so carefully modeled, such as the perception rang e and ang le of view , and th e ini tiatio n process is rev ised acco rding ly. Theoretical analy ses a nd the simulatio n demo nst ra te the ef fectiv eness and the out standing performance of the presented model compared w ith the original placement algo ri thms.
  • References | Supplementary Material | Related Articles

  • Classification and Definition Method of IP Charging and Accounting Parameters for NGOSS
  • CHENG Lu, MENG Luo-ming, QIU Xue-song
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 6-10.
  • Abstract ( 236 )     HTML     　　
  • The nex t g eneratio n operation and suppo rt sy stem ( N GOSS) has been focusing o n management of nex t g eneratio n netw ork. Definition o f the parameters is fundamental fo r the IP charging and acco unting system in N GOSS and classi fica tion act s as a g uideline fo r the defini tio n. Cur rent results had only listed some parameters a nd propo sed a classi fica tion metho d w hich needs to be improved.A classi fica tion and systematic definition method o f IP charging a nd acco unting parameters are presented, w hich hav e been applied in the desig n and implementation of a pro to ty pe.
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  • Research and Implementation of SLA-Driven Distributed Service Management
  • CHEN Jing ,　LI Zeng-zhi,　ZHU Hai-ping,　YAN G Huai-zhou
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 11-15.
  • Abstract ( 189 )     HTML     　　
  • A mapping schema between Web service SLA(service level agreement)and metrics based on traditional management architecture is proposed, and a service management model with active agent is also presented. The mapping schema defines SLA with WSLA (Web service level agreement) language, designs various metricsand schedules based on common information model (CIM), and maps arbitrarily complex SLA parameters into resource metrics that can be easily understood and enforced by the service provider. Through the schedules of the service management model, a resource subagent retrieves metric values from managed resources autonomously and calculates SLA parameters without replying on triggers by an external client so that assured services or SLA can be monitored and management automatically and the overall system resource consumption is reduced significantly. The simulation results have shown that the model can improve the management capabilityof distributed service.
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  • Logic Based Description Model for Multimedia Conferencing
  • WEI Qiang, SU Sen, CHEN Jun-liang
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 16-20.
  • Abstract ( 196 )     HTML     　　
  • The inner logical structure of multimedia conferencing is studied. A logical description model basing on media relationships and dependency relationships is proposed with both formal and non-formal methods. The semantic rules of the model are also given. Then the expansion mechanisms of themodel are studied, including both semantic extensions and structural extensions.As a verification, a sample multimedia conference scenario is described using proposed model. Both practices and analyses have shown that this model can fullymeet the requirements on its functionality, expressivity and extensibility.
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  • The Quality Evaluation Architecture of NGI IP-VPN Service Supporting Multi-Grades
  • ZHANG Ruo-ying, MENG Luo-ming, QIU Xue-song
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 21-25.
  • Abstract ( 235 )     HTML     　　
  • To guarantee the well-balanced, reliable and high-quality service, the specification of service quality evaluation challenges the quality management of NGI (next generation Internet) IP VPN (IP-virtual private network) service. Six IP-VPN service grades are defined and the quality evaluation architecture of NGI IP-VPN service supporting multi-grades is proposed. Then the calculation methods and mathematics formulations are presented in detail. The quality evaluation architecture is applied to the IP-VPN service practically and effectively on solutions and algorithms.
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  • An Interactive Information Framework for the Fast Infoset-Based Network Management System
  • FENG Tuo-yu,　LIU Feng ,　Y AN G Fang-nan
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 26-30.
  • Abstract ( 206 )     HTML     　　
  • The Fast Infoset, a new information interactive format, currently was developedby ISO(International Organization for Standardization)/IEC(International Electrotechnical Commission). This paper analyzes the generic advantages of Fast Infosetdocuments, and provides an interactive information framework for the Fast Infoset-based NMS( network management system ) which is faster to serialize and parse, more efficiently to process and needs less redundancy information. At last,a prototype has been implemented, respectively based on Fast Infoset and XML(extensible markup language) ideas, to test the processing performance of the NMS, and the comparison is presented.
  • References | Supplementary Material | Related Articles

  • Reduction of Alarm Vibration in SNMP-Based Fault Management
  • ZHANG Gang-shan, LI Jian-dong, WU Yu-hong
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 31-35.
  • Abstract ( 237 )     HTML     　　
  • When congestion occurs in a managed network or a managed device is too busy, an NMS (network management system) may acquire an improper state of themanaged device, therefore results in alarm vibration in the NMS. By the analysisof the causation and statistic nature of alarm vibration, a voting algorithm based on probability model is proposed to reduce alarm vibration and improve the efficiency of management. The algorithm takes a vote on the results of continuousdetection of a managed device's state to determine whether or not an alarm vibration has arisen in the NMS and eliminates the vibration occurred during the time range specified by a threshold. The validity of the proposed algorithm has been proved in actual public access wireless local area network management system.
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  • Adaptive Context-Aware Service Policy Platform Based on Parlay API and Agent Techniques
  • ZHAI Xiao-bo,　Y AN G Fang -chun
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 36-10.
  • Abstract ( 212 )     HTML     　　
  • The definition and creation techniques of context-aware service are firstly introduces in this paper. Then Parlay policy management service capabilityfeature(SCF) is simply described. The focus are adding policy agent and policyagent server which are managed by Parlay application programming interface(API),bringing up the idea of context-aware process(CAP) which is running in the mobile terminal, and the design of policies store. This construction moves the adaptive context-aware service to the next generation mobile network service support platform. In the end, the schema advantage of performance and architecture areanalyzed.
  • References | Supplementary Material | Related Articles

  • Description of Service and Resource in Broadband IP Network
  • REN Shu-ting, WU Zhi-mei, GU Guo-chang
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 41-44.
  • Abstract ( 175 )     HTML     　　
  • The concept of network-service of transport layer and applicationlayer have been presented. A mathematic method for describing the transport layer service has been given out. The meaning for quality of service (QoS) has beenanalyzed and its mathematic formula based the method presented here has been provided. The description of network-resource competition has been studied, and its allocation has been given. The description of QoS based the method presented here has been given out too.
  • References | Supplementary Material | Related Articles

  • Anti-Spam Based on Universal Network MeasurementPlatform
  • QIU Xiao-feng, CHEN Ming
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 45-49.
  • Abstract ( 224 )     HTML     　　
  • Based on the universal network measurement platform, a new method for detectingand defending spam is proposed, which is different from existing anti-spam technologies such as Blackhole List and mail filter. The traffic associatedwith mails is gathered into mail flows at the monitor points in local networks,which classified as invalid mail flows, normal mail flows and abnormal mail flows. Then according to the statistical characteristic of the three kinds of mailflows, ad spam, spam virus and abnormal mail behaviors are detected, and interception and alarms are performed by the policy-based responding mechanism.
  • References | Supplementary Material | Related Articles

  • Study and Implementation of Component Based Service forNGN
  • SUN Yue, ZOU Hua
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 50-53.
  • Abstract ( 223 )     HTML     　　
  • Serv ice fo r nex t g eneratio n netw ork based on Parlay API ( application prog ramming interface) i s studied. A component based netw o rk service wi th i ts implementation is presented to meet the need fo r high ef ficiency service dev elo pment. At fi rst , the process o f compo nent based serv ice creation is int roduced, the compo nents architecture is described and the compound component is emphasi zed. Then the functio n, archi tecture and ex ecuting mecha nism of service component and service f ramew o rk is presented. The analy sis of simplici ty and hig hef ficiency are fo llowing. Finally , the dev elo pment and problem of compo nent based service are di scussed.
  • References | Supplementary Material | Related Articles

  • A New Policy-Based Framework for End-to-End Mobile QoS
  • XU Xiao-yu, ZHANG Hui-min
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 54-58.
  • Abstract ( 220 )     HTML     　　
  • After an introduction of the policy-based quality of service(QoS) mechanisms ofuniversal mobile telecommunication system(UMTS), a new policy-based QoS Framework was proposed for the next generation mobile networks. Enhanced policy management components were defined that cover the radio access networks. Hierarchicalpolicy models with common open policy service(COPS) extensions were introduced to achieve adaptive configuration of network resources and QoS negotiation. A specificcase of this policy-based QoS framework was simulated. The performance resultsshow that the required quality of service of the session can be guaranteed. It also benifits the intelligent configuration and adaptive negotiation of the QoS parameters among networks, and eventually the end-to-end QoS can be well guarenteed in the entire networks.
  • References | Supplementary Material | Related Articles

  • Iterative MAP Multi-Code Detection for CDMA System
  • DONG Jiang-bo, WANG Gang, LI Dao-ben
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 59-63.
  • Abstract ( 190 )     HTML     　　
  • The iterative multi-code detection for LAS-CDMA(large area synchronization-code division multi-access) system based on MAP(maximum posterior probability) criterion is studied in this paper. It interchanges the soft information between multi-code detection and channel decoder each other for several times. The iterative detector for non-binary modulation in multi-path fading channel is proposed and the simulation results indicate that the proposed detector can even achieve single-code transmission performance when the iteration times is higher than 3 for QPSK(quadri phase shift key) modulation.
  • References | Supplementary Material | Related Articles

  • DFT-Based Channel Estimation for Uplink MC-CDMA
  • ZHENG Kan, ZENG Guo-yan, WANG Wen-bo
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 64-68.
  • Abstract ( 194 )     HTML     　　
  • Proposes a novel channel estimation algorithm for multi-carrier codedivision multiplex access (MC-CDMA) systems on the uplink. With reasonable constraint and the assistant of special-designed pilot sequence for each user, the discrete fourier transform (DFT)-based uplink channel estimation algorithm can achieve good estimation accuracy without sacrificing much system capacity. Simulation results show the good performances of this method.
  • References | Supplementary Material | Related Articles

  • An Enhancement to Freeze-TCP to Improve Its Performance
  • FAN Rui ,　CHENG Shi-duan
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 69-73.
  • Abstract ( 210 )     HTML     　　
  • A scheme called Freeze-TCP+ is presented to improve the performance of transmission control protocol (TCP) in mobile environment. Freeze-TCP+ is based on Freeze-TCP and incorporates network measurement mechanism. Data sender in Freeze-TCP+ would not send all the packets in the window immediately as it does in Freeze-TCP when handover occurs but set its slow start threshold to a measurement result and start to transmit packets from slow start phase. Freeze-TCP+ solve the problems that Freeze-TCP faces when handover occurs in heterogeneous networks, i.e., many packets are lost due to burst transmission or the resources in the new network can not be utilized efficiently. Network simulation shows that Freeze-TCP+ can improve the performance of Freeze-TCP whatever kinds of handover occur.
  • References | Supplementary Material | Related Articles

  REPORTS

  • Digital Watermarking Algorithm Based on Diagonally Dominant Matrix
  • N IU Shao-zhang ,　GUO Fen-hong ,　N IU Xin-xin
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 74-78.
  • Abstract ( 224 )     HTML     　　
  • A new digital watermarking algorithm based on diagonally dominantmatrix is proposed. The diagonally dominant matrix is constructed by the corresponding nonnegative matrix of the original image. A pseudo-random sequence as digital watermarking is embedded into the built matrix of especial properties by using the scale quantization function. The original image is not neededin the recover progress. Experimental results show that this new algorithm is robust and easy to embed and extract.
  • References | Supplementary Material | Related Articles

  • Performance of the MDAPSK-OFDM Signals in Terms of BER
  • QIN Ya-juan, LIU Yuan-an
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 79-84.
  • Abstract ( 225 )     HTML     　　
  • Compared with the quadrature amplitude modulation (QAM), the differential amplitude and phase-shift keying (DAPSK) modulation is simpler, especially in demodulation. Therefore, the DAPSK method has recently found many applications in orthogonal frequency division multiplexing (OFDM) systems. This paper evaluates the theoretical performance of the 16-, 32- and 64-level multilevel differential amplitude and phase-shift keying (MDAPSK) methods in OFDM systems interms of the bit-error-rate (BER). This paper presents detailed analysis ofthe BERs for the MDAPSK-OFDM signals in an additive white Gauss noise (AWGN) channel and obtains closed-form BER expressions. The theoretical results are verified by computer simulations. The computer simulation results reveal the advantages of using the 16DAPSK or 64DAPSK method in experimental OFDM systems.
  • References | Supplementary Material | Related Articles

  • SLA Management of IP VPN Service Supporting Multi-QoS Classes
  • GUO Li, QIU Xue-song, MENG Luo-ming
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(6): 85-89.
  • Abstract ( 236 )     HTML     　　
  • After analyzing the multi-links and multi-QoS(quality of service) classes characteristics of IP VPN(IP based virtual private network), the special requirements of IP VPN management in service fulfillment, service assurance and integrated evaluation of QoS are proposed. Based on these requirements, an SLA(service level agreement) template comprising items of service,technology and business for IP VPN service management is proposed, and the method of IP VPN service assurance which is based on eTOM(enhanced telecom operations map) framework and management process theories is studied.
  • References | Supplementary Material | Related Articles