Journal of Beijing University of Posts and Telecommunications

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- 2002, Vol. 25 No. 2 Published date:10 March 2002 Last issue Next issue
Review
- Mobile E-commerce and WPKI Technology
- LIU Jie, WANG Chun-meng, FAN Chun-xiao
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 1-7.
- Abstract ( 275 ) HTML 　　
- An overview of mobile e-commerce is given and the technology adopted by mobile e-commerce is analyzed. Based on our practice and research work, we introduce two models of secure mobile e-commerce system based on SMS and WAP in which the WPKI technologies are used.
- References | Supplementary Material | Related Articles
Original articles
- DILC: A Clustering Algorithm Based on Density-isoline
- ZHAO Yan-chang, XIE Fan, SONG Jun-de
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 8-13.
- Abstract ( 304 ) HTML 　　
- A new clustering algorithm, density-isoline clustering(DILC) algorithm is put forward in this paper. DILC starts from the density-isoline figure of samples, and finds relatively dense regions, which are clusters. DILC is capable of eliminating outliers and discovering clusters of various shapes. It is an unsupervisedclustering algorithm because it requires no interaction. The high accuracy andefficiency of DILC clustering algorithm are shown in our experiments.
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- A Modular Neural Network Architecture #br# Based on Parallel Cooperation
- LING Wei-xin, ZHENG Qi-lun, CHEN Qiong, LU Cui-ying
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 14-17.
- Abstract ( 228 ) HTML 　　
- The architecture and algorithm of Parallel Cooperative Modular Neural Network (PCMNN) are proposed in this paper. It has theadvantage of automatic decomposition of given task and its modular training of network. Experiments proposed in this paper is practicable and effective and is superior to non-modular method due to its high efficiency for a parallel network system structure, easy implementation of additional learning and modular structure for implementation by hardware.
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- Semi-jumping the Queue for IP QoS
- YE Ru-yi, SHU Hua-ying
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 18-22.
- Abstract ( 216 ) HTML 　　
- One new kind of queuing technique is put forward. Analysis, simulation and evaluation are addressed at its effectiveness when appliedto router/switch in IP network for differentiated delay control over IP packets.
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- WWW Micropayment Model Based on PayWord
- LI Ming-zhu, LI Zhi-jiang, YANG Yi-xian, NIU Xin-xin
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 23-27.
- Abstract ( 321 ) HTML 　　
- PayWord payment protocol is deeply studied and analyzed. Based on PayWord Micropayment mechanism, payment protocol is necessarily improved and extended, which is more applicable to information payment and access control on WWW. Finally somesuggestion is given to apply it.
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- A Practical Protocol for Electronic Contract
- LI Zhi-jiang, LI Ming-zhu, YANG Yi-xian, HU Zheng-ming
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 28-32.
- Abstract ( 245 ) HTML 　　
- Two properties of electronic contract protocol are pointed out, which are the both sides' equal position and the freedom of valid electronic contract evidence. Based on the two properties, a new practical electronic contract protocol is proposed, which fairness is systematically analyzed. Thenew protocol needs the trusted third party only if the communication channel isdamaged or someone is not honest. When both sides play honestly, one side onlyneeds to unload two messages to successfully finish the protocol.
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- Research on Dynamic Routing and Wavelength Assignment #br# Algorithm in Wavelength Convertible Optical Networks
- WEN Xiang-ming, GUAN Ruo-qi, ZHU Yun, ZHU Xiang-hua
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 33-37.
- Abstract ( 291 ) HTML 　　
- After researching the problem of routing and wavelength assignment in all-optical network, based on the layered-graph model, we propose a dynamic RWA algorithm in the wavelength convertible optical network, which considers the two subproblems of routing selection and wavelength assignment simultaneously. The computer simulation verifies that the algorithm improves thewavelength utilities by virtue of wavelength conversion.
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- Analysis and Comparison of the Different Source #br# Location Point's Thin-wire Dipole Antenna
- LI Chuan-jun, LI Shu-fang, GAO You-gang
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 38-41.
- Abstract ( 301 ) HTML 　　
- The infinitesimal gap mode of a thin-wire dipole antenna is used in FDTD Calculations. The antenna input impedance of thin-wire dipole antenna is calculated using performing deconvolution Gaussian type pulse source. The antenna input impedance's FDTD calculation result of the different excitation source location point's thin-wire dipole antena (center-fed dipole, 1/8-fed dipole, 1/4-fed dipole, and 31/8-fed dipole) are given and discussed. Furthermore, the antenna input impedance's FDTD calculation result of center-fedthin-wire dipole antenna agrees well with the MoM's calculation result.
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- Orthogonal Space-time Block Codes over Rician#br# Fading Environment
- LUO Tao, LI Xiang-ming, YUE Guang-xin
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 42-46.
- Abstract ( 218 ) HTML 　　
- Based on studying the orthogonal space-time block codes over Rayleigh fading environment, the symbol error rate over Rician fading environment is analyzed, and a minimum distance sphere bound of the symbol errorrate is given, from which the “floor effect” of the transmitting antenna number can be obtained.
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- Recursive Construction of Resilient Functions
- WEN Qiao-yan, YANG Yi-xian
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 47-51.
- Abstract ( 218 ) HTML 　　
- Construction of resilient functions that some possible applications of which involve the fault-tolerant distributed computing, quantum-cryptographic key distribution, and random sequence generation for stream ciphers are discussed. It turned out resilient functions are a special case of multi-value correlation-immune functions. Resilient functions are constructed by applying orthogonal array .
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- An Improved Error-correcting Decoding Algorithm for#br# A Class of MDS Array Codes
- LI Xin, ZHANG Zhen-tao, YANG Yi-xian
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 52-56.
- Abstract ( 244 ) HTML 　　
- We improved error-correcting decoding algorithm forB-Code presented in [1]. With the improved algorithm, the error bit can be found accurately in some conditions. Then error-correcting decoding process was completed after only reversing the error bit. But the original algorithm needs to perform more complicated operations, included dual B-Code encoding and code recovering. The improved algorithm is more efficient.
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- Downlink Beamforming for Mobile Communication #br# Systems Based on Different Antenna Arrays
- ZHU Ming-hua, LIU Yuan-an, WU Hui-lan
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 57-62.
- Abstract ( 204 ) HTML 　　
- Downlink beamforming for modile communication systemsbased on antenna arrays have been discussed. Computer simulations for circulararray and linear array have also been carried out. The results of simulations show that circular array or linear array can be used in different downlink beamforming model, which means that circular array is suitable for switch-beam downlink beamforming, while linear array for selective downlink beamforming. If Chebyshev linear array in selective downlink beamforming model is adopt, the beamforming will be optimized. In addition, the complexity of system will be reduced greatly, which makes beamforming easier to be realized.
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- A Study on Enhanced IN Call Model for Supporting#br# VoIP Signaling
- SUN Qi-bo, YANG Fang-chun, SU Sen
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 63-67.
- Abstract ( 234 ) HTML 　　
- With the fast development of H.323-based IP telephony in recent years, the study of integration between the intelligent network (IN) and IP network is becominga spot. We firstly investigate the principle of the integration of IN and IP,and analyze the disadvantages of existing IN basic call model to support VoIP call and the reason。Then we propose an enhanced call model based on layered structure in order to fully exploit the advantages introduced by VoIP signaling and illustrate the integration of the enhanced call model and a typical VoIP signaling—H.323 Recommendation.
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- Research on Distributed Intrusion Detection
- CHAI Ping xuan, GONG Xiang yang, CHENG Shi duan
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 68-73.
- Abstract ( 327 ) HTML 　　
- Through the analysis of current intrusion detection system and CIDF, we proposed a framework of intrusion detection system, and introduced a distributedintrusion detection system that was based on the framework.
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- An Allocating Algorithm of Initial User's Credit#br# Based on Genetic Algorithms
- ZHANG Yu-jie, MENG Xiang-wu
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 74-77.
- Abstract ( 249 ) HTML 　　
- Based on actual experience of telecommunication project, the initial user's credit is introduced. Meanwhile, a formula for calculating it and its allocating algorithm based on genetic algorithms are proposed. The algorithm can reasonable allocate initial degree of user credit. The experimental results also demonstratethe effectiveness of the algorithm.
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- A Mutual Authentication and Key Agreement Protocol in #br# Mobile Communication
- DENG Suo-yun, HU Zheng-ming, NIU Xin-xin, YANG Yi-xian
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 78-82.
- Abstract ( 225 ) HTML 　　
- A new mutual authentication and key agreement protocol is proposed to resolve the problem of identity authentication and key agreement in mobile communications. In the protocol, a mobile user can be provided withanonymous service and neither Visited Networks nor wiretappers know the information of the user's real identity. Being assigned a signing private key and an anonymous digital certificate, a mobile user can be provided non-repudiation service.
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- Study on GIS-based Model and Algorithm for OAN #br# Backbone Optical Cable Routing Optimization
- SU Hui, LU Zhen-hong, WU Li-xin, WANG Jin-zhuang
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 83-87.
- Abstract ( 289 ) HTML 　　
- In this paper we pointed out that the problem about the programming for optical access network belongs to the category of multi-purpose programming problem, and built its mathematical model. It is converted to single purpose programming problem for practicalapplication. We have analyzed deeply three topology structures: star-shapedstructure, line-shaped structure and ring-shaped structure, and presented their routing optimization algorithm based on Dijkstra and priority queue. At last, we realized the mathematical model and algorithm based on GIS enviroment.
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- A New Method of Measurement Based Call Admission Control
- YE Dong, GAO Hong, DING Wei
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 88-92.
- Abstract ( 223 ) HTML 　　
- To solve the problem in implementation of the traditional Measurement-based Call Admission Control, a novel scheme, Quantitative Handling Based Call Admission Control has been proposed, which is measurement-based and practical in engineering. The system implementation including hardware andsoftware is presented in detail. Compared with the existing measurement-basedCAC, the advantages of this method have been stated.
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- The Improvement and Analysis to TCP/IP Congestion#br# Control Mechanism in MPLS
- ZHANG Zhi-qun, DING Wei, WU Mu-qing
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 93-97.
- Abstract ( 261 ) HTML 　　
- The improvement to conventional TCP/IP congestion mechanism in MPLS is proposed, in which endpoint congestion control algorithms aremoved into network. The simulation shows that with the new mechanism, congestioncan be inspected and controlled in time, round-trip delay is reduced and ingress traffic is edited. Thus total throughput and utility of buffer are improved.
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- Application Research of Industrial Engineering in the #br# Field of Communicating Manufacture
- WANG Dan, LIANG Xiong-jian
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 98-101.
- Abstract ( 225 ) HTML 　　
- This paper focusses on finding out solutions to improve internal commu-nicationmanufacturing under the help of Industrial Engineering (IE). Supporting evidence has been displayed by analyzing differences between the foreign and domestic enterprises. According to investigation, the current flow of producing management and manufactureprocess are also described in order to be compared with the former one.
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- Bandwidth Managements over Cisco SRP Ring
- CHAI Hong-jie, ZHOU Wen-li, LEI Zhen-ming
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 102-107.
- Abstract ( 241 ) HTML 　　
- A simple implementation of weighted fairness algorithm for SRP is proposed. Itsapplication to bandwidth management is also studied. Simulation results show that this bandwidth management method has good accuracy.
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- The Design and Simulation of High-speed Router #br# Model Supporting DiffServ in OPNET
- LIN Yu, PENG Yong, CHENG Shi-duan
- Journal of Beijing University of Posts and Telecommunications. 2002, 25(2): 108-112.
- Abstract ( 218 ) HTML 　　
- It is helpful and significative to design a high-speed router model suppporting DiffServ. We design and implement a high-speed router model in OPNET. Someimportant parameters of high-speed router are provided for the design and implementation of router supporting DiffServ in this paper.
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Review

Original articles