Author Login Editor-in-Chief Peer Review Editor Work Office Work

20 December 2009, Volume 35 Issue 24
    

  • Select all
    |
    Degree Paper
  • WANG Dong; CHEN Ying-ying; QIN Ping
    Computer Engineering. 2009, 35(24): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2009.24.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A new method is proposed for speckle noise suppression and airport objects extracting from SAR imagery based on Sequential Nonlinear Filtering(SNF) and Independent Component Analysis(ICA). Speckle noise and image data are separated from multi-polarimetric imagery, and the components with the least speckle index are chosen as the object component automatically by means of ICA. Airport objects are extracted from the separated object component imagery based on sequential nonlinear filtering. Using ENVISAT ASAR polarimetric imagery, experimental results show that the proposed method can extract airport objects rapidly and accurately.
  • LEI Li-hua; MA Guan-yi; CAI Xiao-jing; SHI Hu-li
    Computer Engineering. 2009, 35(24): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2009.24.002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The initial value sensitivity, balance properties and correlation properties of chaotic sequences based on Chebyshev mapping are studied. Performance of chaotic sequences is compared with Gold sequences in DS-CDMA system. Simulation results show that chaotic sequences have approximately the same correlation properties as Gold sequences. As an ideal choice, it is easy to generate a large number of chaotic sequences with good security.
  • ZHOU Wei; ZHENG Jian-rong; LIU Zhang-li
    Computer Engineering. 2009, 35(24): 7-9. https://doi.org/10.3969/j.issn.1000-3428.2009.24.003
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A form feature hierarchy recognition method based on knowledge and graph is proposed to solve the problem of available management of relationship among features. Form features are recognized in different layers including Face Relation Graph(FRG), Simple Form Feature Relation Graph(SFFRG) and Compound Form Feature Relation Graph(CFFRG). Data structure of model and feature recognition algorithms are provided. Experiment shows that the method can simplify Attributed Adjacency Graph(AAG) of parts, and rich feature relationship graph with more engineering information. It provides a new way to establish liaison assembly features.
  • XIA Hong-bin; XU Wen-bo; LIU Yuan
    Computer Engineering. 2009, 35(24): 10-12. https://doi.org/10.3969/j.issn.1000-3428.2009.24.004
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A suitable network simulation system is a software environment to support the study of smart routing algorithm. This paper developes a dynamic network routing simulation system using event driven method. The methods how to simulate the network topology, traffic model, and intelligent network routing protocol are discussed. Experimental result shows that the model can simulate dynamic network and non-precise condition, and can apply to study intelligent routing algorithm.

  • XIANG Hui-hui; LIU Jia-kang; KUANG Jing-ming; WANG Chong
    Computer Engineering. 2009, 35(24): 13-16. https://doi.org/10.3969/j.issn.1000-3428.2009.24.005
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A new technique for analyzing connectivity of Mobile Ad hoc Network(MANET) based on the model of Markov chain model is proposed. A Markov chain model for computing reliability of nodes in the network is established. A Markov chain model of transition of the number of residual nodes and damaged nodes in the network is established, based on which the formulas for computing the probability of connectivity of the node probabilistic networks are proposed. Simulations based on Matlab are used to verify the validity of the analytical formulas.
  • LIU Duan-yang
    Computer Engineering. 2009, 35(24): 17-19. https://doi.org/10.3969/j.issn.1000-3428.2009.24.006
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Incentives are important problem in grids. To pledge mechanisms’ effectiveness, penalty should be introduced. This paper proposes a new penalty model in mechanisms. This model is based on power functions, and it is flexible enough to satisfy lots of penalty requirements. Instance analysis and simulation experiments prove its correctness and effectiveness.
  • XIANG You-jun; WU Zong-ze; XIE Sheng-li
    Computer Engineering. 2009, 35(24): 20-22. https://doi.org/10.3969/j.issn.1000-3428.2009.24.007
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper presents a new fast motion estimation algorithm based on moving direction prediction, called Moving Direction Prediction (MDP) algorithm in which the high correlation of adjacently blocks’ motion vectors and the center-biased characteristic of motion vectors in image sequences are used. The algorithm designs four kinds of patterns and selects patterns to process the image according to its motion direction predicted by referenced motion vectors. Experimental results show that the algorithm excels other traditional algorithms in speed and veracity.
  • SONG Min; WEI Rui-xuan; LI Xia
    Computer Engineering. 2009, 35(24): 23-25. https://doi.org/10.3969/j.issn.1000-3428.2009.24.008
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper studies the design and implementation of multiple Unmanned combat Aerial Vehicles(UAVs) task demonstration system. The demand of this system is analyzed. The multi-layers architecture and function models of this system are presented. In order to solve the cooperative task assignment and path planning problem, the multi-objective optimization models and the improved genetic algorithm are presented. A distribute way is adopted to deal with the contravention of plane model resolving and data real time display. And the digital map tool called MapX is used in the system for war field map display and operations. The system is helpful to maneuver and the exertion of UAVs efficiency.
  • XU Liang; ZHANG Xiao-bo
    Computer Engineering. 2009, 35(24): 26-28. https://doi.org/10.3969/j.issn.1000-3428.2009.24.009
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For a large data set, there is a problem which a kernel matrix K is not easily to be computed very mach for Kernel Principal Component Analysis(KPCA). A fast principal component analysis method is proposed to solve the computation problem for kernel matrix K based on a multi-block feature vector selection. A sample set is extracted by the multi-block feature vector selection. A KPCA model is build up by the sample. The proposed method is applied to a chemical process. Experimental result shows that the proposes method is almost same compared to the KPCA based on the all sample, but, less time are spent on modeling and extracting feature for the proposed method.
  • YI Ying-min; LIU Ding
    Computer Engineering. 2009, 35(24): 29-32. https://doi.org/10.3969/j.issn.1000-3428.2009.24.010
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at colored measurement noise model, this paper presents a Simultaneous Localization and Mapping(SLAM) algorithm for wheeled robot under colored measurement noise. Colored measurement noise model is converted into white measurement noise model by recombining the process model and the measurement model for wheeled robot. In order to make the process noise and the measurement noise irrelevant each other, the process model is re-defined. Estimating state and mapping are conducted in accordance with the virtual process model and the virtual measurement model. In data association step, part observed landmarks are processed as redundant landmarks. Some indicators of the filter are used to evaluate the performance the algorithm. Simulation results show that the algorithm is consistent and robust.

  • ZHAO Jie; XIAO Nan-feng; ZHONG Jun-rui
    Computer Engineering. 2009, 35(24): 33-35. https://doi.org/10.3969/j.issn.1000-3428.2009.24.011
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    By studying IIS, .Net framework and its host environment, user requests are held up to create a kind of new Web log. It uses clustering and other methods to mine new log, and applies information data to trust management of E-commerce. Experiments show that information from new log can enhance all kinds of performances of server and restrict user’s trade behaviors.
  • XING Yi; YE Xin-ming
    Computer Engineering. 2009, 35(24): 36-38. https://doi.org/10.3969/j.issn.1000-3428.2009.24.012
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper presents a statistical learning method to deal with static requirement test of conformance test which is usually dealt with handy methods so it has very low efficiency. Static requirement is demonstrated as rule knowledge. The sampling data are mined to produce association rules. If static requirement complies with association rules, static requirements are statistically correct. The method achieves good results when applying with OSPFv3 protocol conformance test.

  • LI Jing-xia; CHENG Jiu-jun
    Computer Engineering. 2009, 35(24): 39-40. https://doi.org/10.3969/j.issn.1000-3428.2009.24.013
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at resource expression and correctness validation problem of Web service composition, this paper puts forward a formal description model for Web service composition process based on hierarchical colored Petri net. The model can describe control flow and data flow of Web service composition contemporarily, so it can describe composition process comprehensively. It supports correctness analysis and validation of composition process, and can simulate process instance run. Modeling instance demonstrates the effectiveness and practicality of the model.

  • WANG Li-ming; WANG Ming-zhe; YAN Xiao-ling
    Computer Engineering. 2009, 35(24): 41-44. https://doi.org/10.3969/j.issn.1000-3428.2009.24.014
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    According to characteristics of CAN bus extended identifier and requirements of bridge address, this paper constructs transmitting data address form by using extended identifier. Aiming at available net-segment distribution, net-segment and node bit distribution algorithm with net-segment priority and node priority are established, and rate of bit utilization is evaluated. Study algorithm of two dimensions array transmitting address table is analyzed, and building tree algorithm of transmitting single orientation on bridge ports is proposed. Experiments on utilization and delay of bridge under different load and transmission validate prove that the design method of dual-port CAN bridge can implement the functions of CAN bridge.
  • JIA Ning; MA Shou-feng
    Computer Engineering. 2009, 35(24): 45-47. https://doi.org/10.3969/j.issn.1000-3428.2009.24.015
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The existing vehicle detection systems are no longer applicable due to the rapid development of intelligent transport system.This paper develops a new type of vehicle detection system by view it as the foundation data provider in ITS, introduces the architecture of the system and describes the design of its software, which using multi-threading to improve its efficiency, and it is both robust and flexibility because of object-oriented design. The system is put into practice, and shows excellent performance.
  • WANG Tao; LUO Ming-yang; FU Lian-qing; YANG Li-sheng
    Computer Engineering. 2009, 35(24): 48-50. https://doi.org/10.3969/j.issn.1000-3428.2009.24.016
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Compared with MUSIC algorithm, two-dimensional Estimation of Signal Parameters via Rotational Invariance Techniques(ESPRIT) algorithm does not need search peaks of spatial spectrum, so it has less computation. However it needs pair parameters. So a new method for parameters pairing is put forward which is easy to be implemented. The pairing principle is that the sum and difference between eigenvalues of two externalization matrix equal to eigenvalues of sum and difference between two externalization matrixes. A parallel implementation scheme based on Coordinate Rotation Digital Computer(CORDIC) and systolic array is carried out, which only uses shift-adder computation unit. And the simulation by ISE and ModelSim is shown, which proves that the scheme is feasible.

  • Software Technology and Database
  • WANG Han-zhe; SHEN Bei-jun
    Computer Engineering. 2009, 35(24): 51-53. https://doi.org/10.3969/j.issn.1000-3428.2009.24.017
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Database re-engineering is an important part in evolution of enterprise system. Some approaches have been developed in the field of database re-engineering. This paper proposes a Model Driven Architecture(MDA) based unified approach to combine these approaches together. The meta-model involved in the approach is defined, and so is the model transformation between these models. We develop a tool to implement this approach using EMF and Operational QVT, and achieve the automation of database re-engineering.
  • MAO Hong-bao; ZHANG Feng-ming; FENG Hui; LV Hui-gang
    Computer Engineering. 2009, 35(24): 54-56. https://doi.org/10.3969/j.issn.1000-3428.2009.24.018
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problem of multivariate time series similarity search, this paper presents the definition of parameter importance degree and puts forward a candidate sets obtaining method based on it. It extracts singular vector and eigenvector matrix as the features of multivariate time series by SVD, constructs similarity measure modal via coordinate transformation theory in linear space, realizes precise matching on candidate sets and gets ultimate results. Experiments on flight data similarity query show the validity of the method.

  • YANG Jin-cai; JIN Lei; HU Jin-zhu
    Computer Engineering. 2009, 35(24): 57-59. https://doi.org/10.3969/j.issn.1000-3428.2009.24.019
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problem of data isomerism existing in DNA data organizing and processing, a DNA Common Data Model(DCDM) based on XML technology is proposed in this paper. Compared to the ecumenical common data models which have narrow range of application, DCDM has much stronger expansibility, which could be the uniform mode of DNA data description. Experimental result shows that the model can eliminate semantic isomerism in DNA data isomerism.
  • CHEN Bo; WANG Yan-zhang
    Computer Engineering. 2009, 35(24): 60-62. https://doi.org/10.3969/j.issn.1000-3428.2009.24.020
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    When entities are represented by a group of members’ records, the similar records matching problem is extended to record cluster matching problem. This paper proposes two matching patterns of record cluster, establishes mathematical model of record cluster matching by using the theory of weighted bipartite graph, and designs upper and lower bounds matching algorithm of record cluster. It deduces upper and lower bounds of record cluster matching threshold value quickly to decrease the matching times of maximum weight matching between record clusters. Experimental results show that the algorithm can improve matching accuracy and computational efficiency.

  • WEN Chun; SHI Zhao-xiang; XIN Yuan
    Computer Engineering. 2009, 35(24): 63-65. https://doi.org/10.3969/j.issn.1000-3428.2009.24.021
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper introduces an extended association rule which learns Chinese non-taxonomic relation names with linguistics rule after extracting concept pairs with general association rule. This method overcomes the disadvantage of not knowing the name of non-taxonomic relation names with general association rule, confirms the domain and range. Experimental results show that the extended association rule can reach the aim of task well and no need more compact validation between concept pair and its related predicate verb.
  • YANG Tie-jun; NIU Qin-zhou; HUANG Lin
    Computer Engineering. 2009, 35(24): 66-68. https://doi.org/10.3969/j.issn.1000-3428.2009.24.022
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper proposes a general data validation method for multi-module in heterogeneous system. According to the “interface definition” of Interface Definition Language(IDL), it uses the Data validation Configure File(DCF) based on XML to store the definitions of data validating entries, uses a C-like language to define general data validation interfaces, and each module implements the interfaces accordingly to achieve data validation, which is proved by some examples. Through editing DCF directly, it makes the maintenance of data validation fast, and avoids the repeated modification of multi-module, which leads to the efficiency improvement of software development.
  • WANG Hong-bin; LIU Xiao-jie
    Computer Engineering. 2009, 35(24): 69-71. https://doi.org/10.3969/j.issn.1000-3428.2009.24.023
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Reactionary text filtering is a hot research now. This paper proves that statistics χ2 has the unique advantages in the features extraction of the two types of texts based on statistics χ2 analysis. It proposes the threshold δ of the positive texts and infers the value of it in theory, and the K-Nearest Neighbor(KNN) algorithm is improved. This algorithm eliminates the uncertainty of KNN algorithm, realizes no reference, and reduces the time used in the text categorization. Experimental results show that the algorithm meets the real-time online text categorization.
  • MA Qing; LV Yu-qin
    Computer Engineering. 2009, 35(24): 72-74. https://doi.org/10.3969/j.issn.1000-3428.2009.24.024
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A large amount of state memory is consumed when using dynamic compression in SIP signaling compression, which is a great waste of state memory. This paper proposes an effective solution based on structured dynamic dictionary for SIP signaling dynamic compression, and a SIP compression mechanism based on dynamic-dictionary is designed for improving SIP signaling compression combined with LZSS algorithm. Experimental result shows that the new mechanism reduces the time complexity of compression algorithm to some extent and makes effective use of state memory.
  • GUO Peng; GE Wei
    Computer Engineering. 2009, 35(24): 75-77. https://doi.org/10.3969/j.issn.1000-3428.2009.24.025
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper presents a revised decision-tree classification algorithm for customers’ churning, M-AdaBoost cascade of decision tree. By constructing a number of AdaBoosted decision tree classifier, the algorithm produces cascade composition of the decision tree. Experimental results prove the improvement achieved by the new algorithm, and it is better than the result of C4.5 decesion tree, AdaBoost decesion tree and random forest.
  • LUO Zuo-min; ZHU Yan; ZHANG Jing-yi; LI Bing
    Computer Engineering. 2009, 35(24): 78-80. https://doi.org/10.3969/j.issn.1000-3428.2009.24.026
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problem that the system performance bottle-neck caused by a large number of Session data failing to be eliminated in time occurred in the telecom business switching among a number of operations, this paper designs and realizes a Session eliminator based on Servlet filter, which is composed of the Session manager and Session filter. The Session manager can create an object storage area and save the copy of the business Session object. The Session filter is used to check the object storage area and eliminate the rubbish Session data. The validity of this method is proved by pressure test. The method is used in actual environment and achieves success.
  • WEI Li-feng; LIU Dan-bin; WANG Qing-hui
    Computer Engineering. 2009, 35(24): 81-83. https://doi.org/10.3969/j.issn.1000-3428.2009.24.027
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An algorithm instance is designed about traversing Network Address Translator(NAT) for media streams, in which Session Traversal Utilities for NAT(STUN) and Traversal Using Relays around NAT(TURN) based on the Interactive Connectivity Establishment(ICE) are used synthetically. The algorithm explores the NAT topology for peer by the request/response interaction and finds the best path. The program test on Linux proves that media streams are able to pass through various topologies of NAT deployment.
  • GUO Ben-jun; WANG Peng; CHEN Gao-yun; HUANG Jian
    Computer Engineering. 2009, 35(24): 84-86. https://doi.org/10.3969/j.issn.1000-3428.2009.24.028
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    According to the features of Message Passing Interface(MPI), the cloud computing application methods based on MPI, including the MPI cloud computing algorithm design model, cloud computing principles, the core model, and the process are proposed. The distributed characteristic and parallel characteristic are introduced. Theoretical analysis results show this algorithm is feasible, effective and superior to the traditional parallel technology, and it can provide the new method to distributed and parallelize the ordinary algorithms.
  • SUN Yong
    Computer Engineering. 2009, 35(24): 87-89. https://doi.org/10.3969/j.issn.1000-3428.2009.24.029
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Transactional memory is a novel easy-to-use synchronization technology, it simplifies the development of multi-threaded applications. Most transactional memory systems are not applicable and dependent on special hardware currently. This paper proposes a transactional memory system based on C# language aiming at this situation. The system mainly consists of definition of transactional object and its parallel access method, contention management of transaction is also given. Experimental results show that this system is simple and effective synchronization implement mechanism.
  • CHEN Zeng-ke; XIAO Ji-yi; CHEN Ling-na; SHAO Ming-qian
    Computer Engineering. 2009, 35(24): 90-92. https://doi.org/10.3969/j.issn.1000-3428.2009.24.030
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to select data mining services that meet the requirements of users better, this paper uses extension matter-element model to describe data mining service and the requirements of users. By doing extension analysis of data mining service, the similarity degree between candidate data mining service and user required service is calculated. Data mining Quality of Service(QoS) constraint-element of the user is structured. It designs a method to evaluate the similar services and helps the user to choose data mining service which meets the requirement. Experimental results show that the method improves the selection efficientcy.

  • ZUO Li-yun
    Computer Engineering. 2009, 35(24): 93-95. https://doi.org/10.3969/j.issn.1000-3428.2009.24.031
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper presents a rule-driven Web proxy cache model used to improve network performance. This model can find the rule of user access according to the rule of most users’ access action, improve the target hit rate in the cache and make effective use of bandwidth. Based on this model, a cache optimized schedule algorithm is presented. Experimental results verify that the algorithm has feasibility and high performance than other kindred algorithms.
  • LEI Bing-han; HE Jun; HE Xiang; LI Qi
    Computer Engineering. 2009, 35(24): 96-98. https://doi.org/10.3969/j.issn.1000-3428.2009.24.032
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problem that most of the heuristic algorithm can not meet the task’s urgency demand, this paper presents the QoS-based Balance System Loss and Task Complexity(QoS-based BSLTC) algorithm based on the merits of Min-min algorithm and Sufferage algorithm. It joins the QoS parameter in the grid task. During the process of task schedule, the maximal loss task and the maximal computational complexity task is compared based on the distribution loss and measure coefficient. The task which has the most influence on the system is picked out and mapped to the resource with a minimum completion time. Analysis results verify that QoS-based BSLTC algorithm has merits of higher executing efficiency, needing less time to complete the task, high load balance degree and giving consideration to task urgency by comparing with Min-min algorithm and Sufferage algorithm.
  • ZHANG Xiao-wen; HUANG Yong-zhong; LI Zhan-jun
    Computer Engineering. 2009, 35(24): 99-102. https://doi.org/10.3969/j.issn.1000-3428.2009.24.033
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the compensation problem in Web Service transaction processing mechanism, this paper presents a semi-automatic compensation mechanism for the transaction. The mechanism uses the database system triggers technology to solve unified compensation in the distributed and heterogeneous platforms. This mechanism is applied in Web Service, which can standardize compensation logic in order to ensure system consistency. Web Service designers can determine the compensation rules, and dynamically generate compensation at the transaction run-time. Experimental results show this method is beneficial to focus on the use of compensation strategies, with a certain degree of expansibility.

  • DU Qing-feng; MA Hui-jun
    Computer Engineering. 2009, 35(24): 103-104. https://doi.org/10.3969/j.issn.1000-3428.2009.24.034
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper introduces the theory of software process metrics as well as the structure and analyzes method of Shewhart control charts. It discusses the role Statistical Process Control(SPC) plays in software process metrics using an example. As traditional Shewhart control charts can not distinguish the causes from other processes, an improvement is proposed with the help of select cause control charts, which can conquer the deficiencies in the field of software process metrics. It can analyze the stability and performance characteristics of software process both qualitatively and quantitatively.

  • ZHANG Da-peng; QIU Jin-lun
    Computer Engineering. 2009, 35(24): 105-107. https://doi.org/10.3969/j.issn.1000-3428.2009.24.035
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the data access multiformity problems in analysis and design of Service-Oriented Architecture(SOA), a novel SOA-based Data Service analysis strategy is proposed, which makes data entity as core and the task as guide. It uses the method combined with location data entity and analysis data operating to provide a set of design idea for SOA system data access level, and balances the relation between granularity and reuse of Data Service. Experimental results show this method has values of application.
  • LI Guo-qi; LU Min-yan; LIU Bin
    Computer Engineering. 2009, 35(24): 108-110. https://doi.org/10.3969/j.issn.1000-3428.2009.24.036
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to analyze the influence of applying design patterns to software safety in software design, this paper carries out a case study on bridge pattern with Software Fault Tree Analysis(SFTA). The result shows that the application of bridge pattern makes the safety reduce by 50%, but the software modules can be decoupled and redundancy design can be added. Introducing double redundancy can improve software safety by two orders of magnitude. The conclusion is valuable for object-oriented design of safety-critical software.
  • GUO Qing-chang; CAI Qian
    Computer Engineering. 2009, 35(24): 111-113. https://doi.org/10.3969/j.issn.1000-3428.2009.24.037
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    According to the different characteristics of kernel functions, this paper concludes that the mean-shift step may be Newton-step, gauss Newton-step or nonlinear-step. The bound of the density increasing and the position of density maximum at every step are discussed according to the different Taylor series of the mean-shift density functions. The convergence speed can be increased based on such conclusions.
  • WEI Xiao-li; SUN Yong; ZHANG Shu-kui; MIAO Yan-jun
    Computer Engineering. 2009, 35(24): 114-116. https://doi.org/10.3969/j.issn.1000-3428.2009.24.038
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Ontology is the core of the semantic retrieval. Ontology construction mainly includes concept extraction and the extraction of relationship between concepts, and the concept extraction is the base of ontology construction. In this paper, the domain-specific concepts are extracted by the approach which is based on the maximum entropy model, the base noun phrases are mined from the texts in the field, the domain-specific phrases are extracted from the phrases, and the phrases to form the ontology concept are corrected. Experimental results demonstrate the incensement of the accuracy and completeness of the concepts.

  • WANG Bao-jie; WANG Ru-long
    Computer Engineering. 2009, 35(24): 117-120. https://doi.org/10.3969/j.issn.1000-3428.2009.24.039
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to solve the problem that the software architecture in the area of application is difficult to implement, avoid the blindness of software development and improve software quality, through the theoretical study of the orthogonal software architecture, this paper gives its usage in customer relationship management system. The facts are proved that the orthogonal software architecture has the advantages with clear architecture, easy to understand and modify, great efforts to reuse and so on.
  • Networks and Communications
  • DU Xiu-juan; JIN Zhi-gang
    Computer Engineering. 2009, 35(24): 121-123. https://doi.org/10.3969/j.issn.1000-3428.2009.24.040
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper analyzes the limitations of traditional location management scheme and geo-routing, provides a novel location management scheme on K-hops clustering which maintains the whole location information of wireless nodes. Based on the whole network topology information obtained by the K-hops clustering location management scheme, it adopts a heuristic search algorithm to realize optimal geo-routing. Simulation result indicates that the optimal geo-routing based on clustering location management can gain better performance and higher availability on mobile Ad hoc networks.
  • WANG Xiao-nan; TANG Zhen-min; QIAN Huan-yan
    Computer Engineering. 2009, 35(24): 124-126. https://doi.org/10.3969/j.issn.1000-3428.2009.24.041
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper designs a model to implement a seamless communication between a Wireless Sensor Network(WSN) and an IPv6 network. This model creates an automatic address configuration algorithm in a sensor network, and based on the algorithm this model performs automatic routing and addressing. It puts forward a reduced IPv6 protocol stack to save a sensor node’s power. This model is implemented in both an experimental platform and a simulation environment, and its performance is analyzed. Experimental results prove the validity and correctness of this model.
  • HE Ying-jie; WANG Hui-qiang; ZHOU Ren-jie
    Computer Engineering. 2009, 35(24): 127-129. https://doi.org/10.3969/j.issn.1000-3428.2009.24.042
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    By analyzing and comparing all kinds of domestic and overseas network topology discovery methods, this paper proposes a real-time network topology discovery algorithm based on Simple Network Management Protocol(SNMP), which is oriented network situation awareness. It concludes technologies of estimation of network device’ activity, estimation of network device’s type, storage and disposal of network topology information, and has the advantages of high real-time and accurate discovery compared with traditional ones. Experiment proves that the algorithm is feasible and accurate.

  • YIN Ai-han; ZHANG Pei-zhou; JIAO Yue-li; HUANG Chang-sheng
    Computer Engineering. 2009, 35(24): 130-132. https://doi.org/10.3969/j.issn.1000-3428.2009.24.043
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper proposes an adaptive dual-clocking algorithm, which can effectively solve the problem of light-load deterioration in Ethernet Passive Optical Network(EPON) without increasing the delay of Expedited Forwarding(EF) service, and decrease the delay of Assured Forwarding (AF), Best Effort(BE) and other low-priority services. Its clocking can be changed according to actual situations and it improves the slot waste to a certain extent. A system working model with OPNET is established to realize simulation, the result indicates that the algorithm can decrease the average network delay and enhance the network turnover.

  • ZHANG Ze-qi; HAN Guo-dong; HUANG Wan-wei; ZHENG Liang-quan
    Computer Engineering. 2009, 35(24): 133-135. https://doi.org/10.3969/j.issn.1000-3428.2009.24.044
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    As link failures are in regular Network on Chip(NoC), XY routing can not keep the communication natural. This paper proposes an adaptive routing algorithm based on the awareness of link-state in order to keep the communication well after the link failures. Simulation result of this algorithm shows that the nodes can keep communicating with each other with failures in network. Also, with some date injecting rates, the throughputs can hold the line before or after the failures in the network.
  • LI Xue-yong; HUANG Jia-wei; WANG Jian-xin
    Computer Engineering. 2009, 35(24): 136-138. https://doi.org/10.3969/j.issn.1000-3428.2009.24.045
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problem that the wireless channel resources are significantly unfairly allocated among the uplink TCP flows in WLAN, this paper proposes an uplink TCP flow schedule algorithm named UFWFQ(Up Fair WFQ). It uses the same polling as Weighted Fair Queuing (WFQ) at Access Point(AP). The service weights are dynamically set according to the transmission rate of flows. Flows with high transmission rate get more opportunities, and each flow occupies the same channel time. As a result, UFWFQ achieves the weighted fairness between single flow and total network efficiency. Simulation result proves that UFWFQ is effective.
  • WU Wei-ji; ZHENG Tao
    Computer Engineering. 2009, 35(24): 139-142. https://doi.org/10.3969/j.issn.1000-3428.2009.24.046
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For the problem that the centralized network proxy server would become a bottleneck, this paper provides a solution to network-proxy services. Nodes which participate in the system compose a Peer to Peer(P2P) overlay network based on HeteroPastry protocol, and the system chooses several appropriate nodes to form a proxy chain in order to response users’ varied requests. Experimental results show that the system can balance the load upon the network efficiently when providing high quality services.
  • TANG Li; LEI Xiang-dong; DUAN Hong-liang
    Computer Engineering. 2009, 35(24): 143-145. https://doi.org/10.3969/j.issn.1000-3428.2009.24.047
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper proposes an adaptive hybrid broadcast algorithm. It adopts skewed data allocation in periodic broadcast channels to make frequently requested items broadcast more frequently. When determining the number of periodic broadcast data and on-demand broadcast data, it considers the relationship between the response time of on-demand broadcast channels and the requests arrival rate, and gets the optimal cut-point after a spot of comparison. According to the changes of system load and clients’ access patterns, it can adjust the channel and data allocation and minimize the average access time. Experimental results show that the algorithm can adjust the channel allocation and data classification dynamically depending on the change of the server workload and query access patterns, performs better than exclusive broadcast and exclusive on-demand broadcast, and access time is less than existing hybrid data broadcast.

  • Security Technology
  • LI Li-le; LIU Guo-hua; SONG Jin-ling; HE Li-rong; ZHANG Yu
    Computer Engineering. 2009, 35(24): 146-149. https://doi.org/10.3969/j.issn.1000-3428.2009.24.048
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In probabilistic databases, the uncertainty of publishing views and private information is the main factor influencing the effect of views security decision. Aiming at this problem, this paper uses entropy to describe the uncertainty of publishing views and private information, which transforms this problem from deciding views security to calculating entropies, introduces an entropy-based views security decision theorem, and proposes an entropy-based views security decision algorithm. Experimental result shows that the algorithm can effectively determine the security of publishing views.

  • GU Xiao-dan; XIAO Wei; ZHANG Fan
    Computer Engineering. 2009, 35(24): 150-152. https://doi.org/10.3969/j.issn.1000-3428.2009.24.049
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper works on how to apply the technology of disaster tolerance and disaster decrease to the developing aerospace TT&C field, and suggests a remote disaster tolerance schema of the aerospace TT&C center, including the risk analysis of the system, the structural system design, and the actualization schema. Analysis result shows that the scheme can improve the security and work efficiency of the TT&C system effectively.

  • WU Lei; XU Rong-sheng;
    Computer Engineering. 2009, 35(24): 153-155. https://doi.org/10.3969/j.issn.1000-3428.2009.24.050
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Survivability analysis is based on events analysis. Event-base construction is the top priority of it. This paper presents a purpose-driven approach for event generation based on vulnerability correlation and proves its correctness and efficiency by a case study. This approach-lays a foundation for further study and design of survivability analysis.
  • YU Tian-tian; FENG Quan-yuan
    Computer Engineering. 2009, 35(24): 156-157. https://doi.org/10.3969/j.issn.1000-3428.2009.24.051
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper introduces several typical methods to against security and privacy problems, and aim at the shortages in them and other improved ones which provided by some literatures, proposes a new improved scheme based on hash function. The modified scheme resists illegal access, tracking, eavesdropping, impersonation and replay attack, fits for the case which the tags and readers number is large and is security and efficiency.
  • YANG Hong-mei; HU Yu-pu; GAO Wei
    Computer Engineering. 2009, 35(24): 158-161. https://doi.org/10.3969/j.issn.1000-3428.2009.24.052
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The goal of password-based group key exchange is to establish a high entropy session key used for secure communication through a low entropy password, reach the multi-security requirement among members. This paper introduces two random numbers to improve security, Hash function is used to optimize the password, makes sure the fressness. It proposes a provably secure password-based protocol under standare model, and gives it the analyse security.

  • ZHANG Xin-he; ZHANG Yue-hua; LIU Hong-yan
    Computer Engineering. 2009, 35(24): 162-164. https://doi.org/10.3969/j.issn.1000-3428.2009.24.053
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper presents an architecture for 16-bit datapath Advanced Encryption Standard(AES) IP core based on FPGA. It uses finite state machine, and supports encryption, decryption and key expansion. The round-key is calculated before the beginning of encryption/decryption. It consumes less hardware resources. It is implemented on Cyclone II FPGA EP2C35F484, which consumes 20 070 logic elements, less than 60% of the resources. The IP core can operate at a maximum clock frequency of 100 MHz. Compared with 128-bit datapath AES, it can interface with CPU easily.
  • YU Xiao-bing; GUO Shun-sheng; YANG Ming-zhong
    Computer Engineering. 2009, 35(24): 165-167. https://doi.org/10.3969/j.issn.1000-3428.2009.24.054
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper presents an extended Role-Based Access Controls(RBAC) model based on Core RBAC model. The model discusses object sets and operation sets in detail, established groups. It carries out restrictions on power in three dimensions and realized application-oriented architecture. It enhances security and maintenance. The model is applied to Enterprise Resourse Planning(ERP) system. It is the typical representative of enterprise information system. Application result in enterprise shows that the extended model is totally suitable to it.
  • XU Cheng-qiang; LI Zuo-wei
    Computer Engineering. 2009, 35(24): 168-169. https://doi.org/10.3969/j.issn.1000-3428.2009.24.055
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    After analysing one one-time-password authentication scheme proposed by Zhang Hong and Chen Zhigang, some insecurities such as data storage and can not resist denial of service attacks are pointed out. The scheme is improved with simplicity of one-time-passwords and cryptography technology and the USB Key media. A more secure authentication scheme is produced and the safety analysis is given. Results show that the sheme is easy to operate, secret and safety, and has less system consumption.

  • SHAN Yi-hui; JIANG Yu-ming; TIAN Shi-yuan
    Computer Engineering. 2009, 35(24): 170-173. https://doi.org/10.3969/j.issn.1000-3428.2009.24.056
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Pattern matching is an important algorithm, used by most of intrusion detection system at present. On the basis of analyzing some pattern matching algorithms commonly used, an improved algorithm based on BMHS algorithm, N-BMHS algorithm, is presented. The algorithm adopts the way of matching from both ends to the center, and uses a new array s to record the appearing times of each character in the pattern string. When it equals one, the matched information is used to help getting the maximum moving distance of the pattern. Experimental results show that the improved algorithm can reduce the times of comparing and enhance the matching speed effectively.

  • WANG Xing; DING Hong; LI Xin
    Computer Engineering. 2009, 35(24): 174-175. https://doi.org/10.3969/j.issn.1000-3428.2009.24.057
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Identity-Based Encryption(IBE) provides much more convenience against traditional public key cryptography, but newly proposed schemes can not eliminate key escrow. Aiming at this problem, this paper proposes a new scheme to control key escrow or eliminate it completely. In this model, users are divided into different groups and these groups are associated with each other by inter-trust. A key agreement protocol based on it is provided. Analysis result proves that the model does not need extra infrastructures, and does not increase the cost of computation or communication for key agreement.
  • YOU Juan; TANG Guang-ming
    Computer Engineering. 2009, 35(24): 176-178. https://doi.org/10.3969/j.issn.1000-3428.2009.24.058
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Most tools are based on Least Significant Bit(LSB), which makes the steganography on LSB a wide significance. Based on steganography ideas of bit planes and neighbor pixels correlation in image, with some inherent features of 16 bit coded wav audio and statistical changes by audio LSB, a conclusion of the statistical result in algorithm increasing is made by the neighbor vectors value and odd-even discussion. Theory and experimental results with a setting threshold value prove it is feasibility.
  • Artificial Intelligence and Recognition Technology
  • LIU Sheng; FU Hui-xuan; WANG Yu-chao
    Computer Engineering. 2009, 35(24): 179-181. https://doi.org/10.3969/j.issn.1000-3428.2009.24.059
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    By using Least Squares Support Vector Machines(LS-SVM), it need not consider internal and external parameters to achieve the camera calibration. Because the lens distortion is mostly caused by radial distortion, according to the camera distortion characteristic, it divides the distortion region. A new method of camera calibration based on divided region LS-SVM is proposed, and the distortion of different regions deals with separately. The comparison with other methods including BP Neural Network(BPNN) and LS-SVM shows that the calibration accuracy is improved by using the divided LS-SVM method, and the speed is higher.
  • ZENG Chun; LI Xiao-hua; ZHOU Ji-liu
    Computer Engineering. 2009, 35(24): 182-184. https://doi.org/10.3969/j.issn.1000-3428.2009.24.060
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The drawbacks of pedestrian detection method based on Histograms of Oriented Gradient(HOG) are larger dimensions of features and slow detection speed. Aiming at this point, a method based on HOG of Region Of Interest(ROI) is proposed. HOG is calculated in four important regions which locate in head and limbs’ regions respectively. Through this method, dimensions of features are decreased effectively. Experimental results show this method speeds up detection process while maintaining comparably accuracy to the method based on HOG.
  • ZENG Xiao-hui; WEN Zhan
    Computer Engineering. 2009, 35(24): 185-187. https://doi.org/10.3969/j.issn.1000-3428.2009.24.061
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    According to the definition and characteristic of incomplete information system, this paper establishes rough set model based on set error tolerance relationship, constructs discernable matrix of condition attribute, and analyzes importance of decision attribute. It expatiates and compares three kinds of attribute reduction method. Processing results on one incomplete information table show that the three kinds of method have the almost same reduction results and validity.
  • SUN Wei; ZHUANG Wei-hua; LIN Hong-fei; ZENG Xiao-qin
    Computer Engineering. 2009, 35(24): 188-190. https://doi.org/10.3969/j.issn.1000-3428.2009.24.062
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    According to the geometry distribution property of Support Vector(SV), this paper proposes the concept of adjacent boundary model and SV pre-selecting algorithm. By pre-selecting adjacent boundary samples, lots of samples are avoided to solve Quadratic Programming(QP) problems, which provides efficient training sets for SVM. Experiments show that it can improve efficiencies of training time and space by using the algorithm in LIBSVM.

  • FAN Kang-xin
    Computer Engineering. 2009, 35(24): 191-193. https://doi.org/10.3969/j.issn.1000-3428.2009.24.063
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    There are some shortcomings when it uses single Naïve Bayes(NB) classifier to classify text. For example, the classification model is sensitive to samples, and the precision is always hard to be improved. This paper proposes a method that creates different feature set which is used in training NB classifier using different method to extract text features in each iteration of Boosting procedure. An NB combination classifier for text categorization is designed based on different feature selection methods. Experimental result shows that the combination classifier is more effective than single NB classifiers.
  • DENG Chang-shou; ZHAO Bing-yan; LIANG Chang-yong
    Computer Engineering. 2009, 35(24): 194-195. https://doi.org/10.3969/j.issn.1000-3428.2009.24.064
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An improved Differential Evolution(DE) algorithm is proposed to improve the convergence speed of the traditional DE in solving the complex optimization problems. In the new algorithm, only one array is used to improve the exploration ability. And a second local mutation operator is proposed to improve the exploration ability, which makes some individuals of the current population search the field around the current best individual. Several different kinds of benchmark functions are used to test the algorithm. And the results are compared with that of DE algorithm, of Dynamic Differential Evolution(DDE) and Particle Swarm Optimization(PSO). Simulation results show that the efficiency of the improved differential algorithm is improved greatly.
  • JIA Rui-yu; LI Yong-shun; LI Jing-cheng; FENG Lun-kuo
    Computer Engineering. 2009, 35(24): 196-198. https://doi.org/10.3969/j.issn.1000-3428.2009.24.065
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at solving the conflict between validity and extensibility of the covering algorithm, this paper combines good point-set genetic algorithm with covering algorithm, and presents a good point-set genetic covering algorithm. The algorithm brings competition in the population of cover sets, eliminates the poor cover and retains the better cover, signally reduces the number of coverage and the number of samples rejection, so it raises the classification capacity of the total population. By comparing with Lib-SVM and neighborhood covering and alternative covering algorithm, experimental results prove that this algorithm has a good validity and extensibility.
  • XIAO Zheng; ZHANG Shi-yong
    Computer Engineering. 2009, 35(24): 199-201. https://doi.org/10.3969/j.issn.1000-3428.2009.24.066
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on utility-based action selection model, this paper researches on personality modeling in multi-Agent system. That artificial neural network can learn target function which is hard to comprehend draws attention. So an individualized neural network is built according to five-factor model in psychology. Different setting on parameters reflects the way that personality influences utility of actions. This model has stronger ability to describe personality. A gradient descending learning algorithm is proposed to train the individualized neural network. The model is validated on personality exhibition during action selection.

  • Graph and Image Processing
  • WANG Hui; WANG Lai-sheng; ZHONG Ping
    Computer Engineering. 2009, 35(24): 202-204. https://doi.org/10.3969/j.issn.1000-3428.2009.24.067
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To deal with the disadvantages of Chan-Vese model(C-V model), such as convergence slowness, a level set image segmentation algorithm based on scale transform of edge detection function is proposed. This paper improves the C-V model by introducing the edge detection function, and increases the speed of image segmentation without lowering the quality of segmentation. In order to boost up the flexibility of the improved model, a technique of scale transform to act on the edge detection function is proposed. Experimental results show that the improved model can achieve good effect, and the scale transform can effectively speed up the evolution of the improved model and maintain the stability of segmentation process.

  • LIU Qian; LI Xiang-lin; LU Xin-hong
    Computer Engineering. 2009, 35(24): 205-207. https://doi.org/10.3969/j.issn.1000-3428.2009.24.068
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper presents an adaptive Multi Scale Retinex(MSR) method based on region segmentation. The method of image segmentation by region for the different illumination of the scene, which has illumination changes spatial acutely on the edge. The modified filter takes the regional information into account to reduce the coefficient illumination between the different regions, so as to achieve the purpose of inhibition halo. The improved MSR method achieves visual quality enhanced images as well. Through the experimental results and data analysis, this method is approved to be effective, and provides satisfied result.

  • ZHANG Gui-hua; WANG Cheng-liang
    Computer Engineering. 2009, 35(24): 208-210. https://doi.org/10.3969/j.issn.1000-3428.2009.24.069
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Combining the particular application in geological exploration, by the control of depth, the sequence of images, reflected from the space of entire section(360o) of the borehole wall, is presented as annuals images on the screen. The overlapping part between the two sequence images are chosen based on the theory of image stitching error. A new seed filling method based on link queue is used to find the center and radius of the circle. By traversing every concentric circle according to a given angle, the annular images are expanded into rectangle. Using the overlapped information between two sequence images and grid matching method, it makes the sequence images stitch smoothly which are more convenient for observation.
  • LI Da-jin
    Computer Engineering. 2009, 35(24): 211-212. https://doi.org/10.3969/j.issn.1000-3428.2009.24.070
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In a single image generated from texture synthesis, the texture pattern scale is expected to be nonhomogeneous for time to time. With this ideal, this paper presents a simple and efficient texture synthesis algorithm that user can control the basic pattern scale varying from big to small or from small to big consecutively in different location of a single image. In the process of synthesis pixel by pixel, it constructs a positive direction map to multi-resolution textures for the best-match pixels. Through resampling these pixels, it can control the synthesis result arbitrarily. Experiment proves that the algorithm is free from suffering vast extra process time and easy to code, and it also can be applied to most synthesis algorithms that synthesize a texture one pixel at a time.

  • YU Hong-yun; JIANG Tao; GUAN Jian
    Computer Engineering. 2009, 35(24): 213-215. https://doi.org/10.3969/j.issn.1000-3428.2009.24.071
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A Synthetic Aperture Radar(SAR) image detection algorithm which unifies with the data related base and the fixed base is proposed. The target features which are extracted in two kind of different spaces are fused separately. They are modulated each other. The target features can be protruded by this algorithm. The targets are detected by using the priori knowledge in the saliency map. Experimental results with ADTS target high-resolution airborne SAR data show that the target area can pop out with the background being restrained and the algorithm has higher detection accuracy.
  • Multimedia Technology and Application
  • ZHU Zi-yuan; LIN Tao
    Computer Engineering. 2009, 35(24): 216-218. https://doi.org/10.3969/j.issn.1000-3428.2009.24.072
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper presents a low power, configurable and low cost MPEG-1/2 Layer I/II/III audio decoder. The decoder consists of a software core and a hardware core and has two operation modes, “high quality” mode and “power saving” mode. In the “high quality” mode, the decoder is a full compliance MPEG audio decoder. In the “power saving” mode, a cut-off sub-band synthesis filter and downsampling architecture is proposed. Using the new architecture, the power consumption of the decoder is decreased further more.

  • CAI Shu-ting; WANG Qin-ruo; XIE Yun; YIN Ming
    Computer Engineering. 2009, 35(24): 219-221. https://doi.org/10.3969/j.issn.1000-3428.2009.24.073
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of transmitting in the lossy channel and the requirement communication between the sensors for traditional wireless video sensor networks, a robust multi-view distributed video coding system is proposed. By using modified PRISM codec schemes, the correlation of all views to is explored to get more gains of compression. The redundancy also is used to enhance the system robust for intrinsic wireless lossy channel. Experimental results show that the proposed system accesses the compression gain, and system is also robust to wireless lossy channel.

  • ZHOU Feng; WU Yun; ZHAO Yong
    Computer Engineering. 2009, 35(24): 222-224. https://doi.org/10.3969/j.issn.1000-3428.2009.24.074
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    AMR-WB+ is the newest audio compression standard which is used in 3G mobile communication systems. This paper analyzes the frame error concealment algorithm for pitch delay parameter in AMR-WB+, and gives the scheme of optimization. Experimental results show that, on average, the objective test score of the optimized algorithm is higher than the original algorithm, and the subjective test score of the optimized algorithm is equal to the original algorithm.
  • CHEN Rui; JIAO Liang-bao
    Computer Engineering. 2009, 35(24): 225-228. https://doi.org/10.3969/j.issn.1000-3428.2009.24.075
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the drawbacks in AMP-Live model, a NEW Adaptive Media Playout(NEWAMP) algorithm based on packet-delay prediction is proposed. The main modification is that, the predicted value of the future channel and the buffer state may be used as the basis of playout policies. Moreover, after thining the playout speed and considering the maximum end-to-end delay, the algorithm performance may be improved further. In contrast to the classical media playout, NEWAMP algorithm decreases the average buffer delay more than 50 percent with low enough packet loss ratio of overflow and downflow. To the traditional AMP-Live algorithm, not only the packet loss ratio of overflow and downflow is decreased, but also the average buffer delay is deceased almost 40 percent. Experimental results show this algorithm is effective.
  • YUAN Tao; WANG Tong-qing
    Computer Engineering. 2009, 35(24): 229-231. https://doi.org/10.3969/j.issn.1000-3428.2009.24.076
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To accelerate the motion search process, this paper proposes a novel adaptive dynamic search range algorithm. It selectes dynamically the predictive Motion Vector(MV), whose relevant referenced block is most correlative with the current block, in candidate MV set of backward fast motion estimation algorithm as the center of search range. It determines adaptively the unsymmetrical search range in negative/positive direction of horizontal/vertical axis according to the predictive MV set to reduce the search points. Extensive experiments show that this proposed scheme, combined with UMHexagonS and FFS, can achieve more than 22.13% and 76.57% computational reduction of motion estimation respectively, compared with the previous algorithms, while maintaining almost the same quality of reconstructed pictures.
  • ZHOU Tao; ZHANG Mao-jun; LIU Shao-hua; XIONG Zhi-hui
    Computer Engineering. 2009, 35(24): 232-235. https://doi.org/10.3969/j.issn.1000-3428.2009.24.077
    Abstract ( ) Download PDF ( )   Knowledge map   Save

    The usage of various prediction modes is the remarkable characteristic of H.264/AVC, however, it acquires heavy computation. Aiming at this problem, a fast mode decision algorithm is proposed for H.264/AVC encoding, which is on the basis of the application of all-zero blocks detection. By skipping some prediction modes after some comparisons, the algorithm can reduce the computational complexity of H.264/AVC encoding.

  • Engineer Application Technology and Realization
  • MA Xiao-jing; LIU Liang; YE Fan; REN Jun-yan
    Computer Engineering. 2009, 35(24): 236-238. https://doi.org/10.3969/j.issn.1000-3428.2009.24.078
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to reduce the hardware consumption in high speed communication system, a high speed Multi-Input and Multi-Output(MIMO) signal detector applied for MIMO-OFDM wireless communication system is presented. According to the the requirement of reconfigurable design, a Simplified K-Best(SKB) algorithm as well as a reconfigurable structure for MIMO signal detector is proposed. The MIMO signal detector is implemented on Xilinx Vertex-4 FPGA platform. Simulation experimental results show the throughput of this detector achieves 2 Gb/s and has the function of demodulating different modulation such as QPSK and 16-QAM.
  • XU Tian; HE Dao-jun; XU Jin-fu
    Computer Engineering. 2009, 35(24): 239-241. https://doi.org/10.3969/j.issn.1000-3428.2009.24.079
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A design scheme for PCI Express interface based on IP-core is proposed, which uses storied structure and has such characteristics as high performance, high reliability and software compatibility. The PCI Express bus interface is designed and implemented by using PCI Express endpoint block hard IP-core in Xilinx xc5vlx30t Field Programmable Gate Array(FPGA). A DMA controller is also designed inside the interface logic circuit. Simulation experimental results show this interface speeds up the frequency of data transfer and the high performance of PCI Express bus is demonstrated adequately.
  • CHE Jin-hui; XUE Man-ling; JIANG Feng
    Computer Engineering. 2009, 35(24): 242-243. https://doi.org/10.3969/j.issn.1000-3428.2009.24.080
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    CAN bus real-time scheduling algorithm is proposed to satisfy the need for real-time and bandwidth dynamic allocation of CAN bus in electric vehicle. Backend channel configure database is used for modification of CAN bus channels at runtime. Requirements of modification in research and execute phases are meet properly by this algorithm. The algorithm shortens the time of the research and development time.
  • GAO Jian-shu; XU Liang-liang; MA Yu-ling
    Computer Engineering. 2009, 35(24): 244-246. https://doi.org/10.3969/j.issn.1000-3428.2009.24.081
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problems of environment control in cabin fire emergency rescue training simulation system, this paper presents a multi-point temperature and smoke monitoring system based on single chip microcomputer AT89C52. This system can measure and control the fire atmosphere of simulation real-time system, such as smoke and temperature. In order to control training environment more accurately, data fusion method based on arithmetical and batch estimation, along with PID control algorithm are united, which improves the precision of temperature and smoke. It solves the error caused by sensor failure. Experimental results show this system is effective.
  • Developmental Research
  • ZHANG Yi; LIU Cheng-gang; XING Deng-peng
    Computer Engineering. 2009, 35(24): 247-249. https://doi.org/10.3969/j.issn.1000-3428.2009.24.082
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The design of motor control system for small humanoid robots to realize motion control and coordination of multiple freedom degrees is a nodus of robot technology. Aiming at the demerit that traditional controllers are only applicable for controlling a small number of motors, which impedes joint coordination, this paper proposes a novel Digital Signal Processor(DSP)-based motor control system. The integration of DSP controller, motor control integrated circuit and quadrature decoder unit unleashes moving control potential of DSP, and realizes real-time control among multiple joints. Experimental results demonstrate that the system can provide satisfactory control precision.
  • CHEN Bin; LIU Bao-hong; HUANG Ke-di
    Computer Engineering. 2009, 35(24): 250-252. https://doi.org/10.3969/j.issn.1000-3428.2009.24.083
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper introduces the structure and feature of the component-based simulation systems. It presents the Web-based technique to mange component resources and the method of Web-based simulation system management. The structure of component resource database and the working principle of simulation management method are described. It expatiates the design mentality of the services to control simulation process and the structure of Web server for management and control. Analysis results show that the method can be used in eXtensible Modeling & Simulation Framework(XMSF)
  • FENG Yu-qiang
    Computer Engineering. 2009, 35(24): 253-254. https://doi.org/10.3969/j.issn.1000-3428.2009.24.084
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problem of tangency point reorganization of digital curve, this paper proposes a digital curve tangency point detection technology based on rotate-angle accumulation. The technology uses smooth processing for digital curve, constructs rotate-angle accumulation curve, curvature curve of rotate-angle accumulation curve and curvature wave, and determines the tangency points according to the intersection of every two adjacent fitted line. Experimental results show that tangency point reorganization of this method is correctly and quickly, it can realize subsection correctly for figure boundary composed by straight line and circular arc.

  • QIAO Guo-lei
    Computer Engineering. 2009, 35(24): 255-256. https://doi.org/10.3969/j.issn.1000-3428.2009.24.085
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    According to the error-correcting capability complementarity of Chase decoding algorithm and Ordered Statistic Decoding(OSD) algorithm, a new Chase-OSD parallel decoding algorithm for RM codes is proposed, in which, OSD algorithm processes certain MRIPs of a received sequence, while Chase-type decoding algorithm processes certain LRPs of a received sequence. If there are at least i+1 MRIPs of the ordered received sequence in error, OSD algorithm will fail. On the other hand, if the number of errors in the LRPs is large, the Chase-type algorithm will fail. A parallel decoding algorithm based on complementary characteristic is proposed. Simulation experimental results show this algorithm can achieve better decoding performance.

  • WANG Yan-sheng; LIU Lei-bo
    Computer Engineering. 2009, 35(24): 257-258. https://doi.org/10.3969/j.issn.1000-3428.2009.24.086
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at clock network’s function in SoC chip and its own characteristic, this paper studies and implements three kinds of clock low power consumption techniques including using dynamic clock management technique to cut down and distribute module’s clock dynamicly in system level, inserting clock gating cells based on power consumption optimization tool named Power Compiler during logic synthesis, and doing a low power consumption Clock Tree Synthesis(CTS) targeting on clock tree’s dimension during clock tree synthesis. These three techniques are implemented during the design of audio and video decoding chip, and the results show that their power consumption optimization effects are obvious.

  • CHEN Peng-cheng; CAO Zhang-hua; YAN Ting-su; TANG Yuan-sheng
    Computer Engineering. 2009, 35(24): 259-261. https://doi.org/10.3969/j.issn.1000-3428.2009.24.087
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper proposes a coset-based Quasi-Cyclic Low Density Parity Check(QC LDPC) construction method and similar SFT-LDPC code construction method in order to guarantee the girth under high bitrate. It gives two necessary conditions of girth at least 6 when the size of cyclic permutation matrix is a composite number. This construction method with various lengths, rates and girth at least 6 can be flexiblely constructed. Simulation results show that the code constructed by this method is comparable to random ones in error correction performance over additive white Gaussian noise channel.
  • TANG Wen-wei; SHEN Bei-jun; CHEN De-lai
    Computer Engineering. 2009, 35(24): 262-264. https://doi.org/10.3969/j.issn.1000-3428.2009.24.088
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Business process management and Service Oriented Architecture(SOA) provide a solution to the highly efficient integration of enterprises. Based on model driven development theory, this paper proposes a refined meta-model for business process. It solves the problems of model transformation, discusses the checkout method of controlling flow structure and semantics, designs and realizes a process modeling tool based on the meta-model according to the model driven architecture.
  • FANG Hong; LV Tai-zhi
    Computer Engineering. 2009, 35(24): 265-267. https://doi.org/10.3969/j.issn.1000-3428.2009.24.089
    Abstract ( )   Knowledge map   Save
    Aiming at the problem that using the script of Web page widely, the traditional search engine is difficult to extract the information, this paper uses HtmlUnit to interpret JavaScript dynamic Web page, and uses Selenium IDE to extract XPath of dynamic element, the seeking-job search engine extracts successfully the information of Web page produced dynamically. Experimental results show that this technology is useful.
  • CHEN Chun-fang; LI Yan;
    Computer Engineering. 2009, 35(24): 268-270. https://doi.org/10.3969/j.issn.1000-3428.2009.24.090
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Spatial location is one of the most important functions in WebGIS. Scalable Vector Graphic(SVG) is considered an important developing tool of WebGIS, but it is lack of complete representation in spatial location, SVG can not realize spatial location and transformation in SVG map directly. Aiming at these problems, this paper proposes a SVG-based spatial location model and defines its formal representation. It designs and implements SVG spatial location function module, which is open, cross-platform and reusable. Applied example proves that the model can get good visualization location effect and accurate spatial location.
  • ZUO Wei; FENG Jin-fu; XU Ling-quan
    Computer Engineering. 2009, 35(24): 271-273. https://doi.org/10.3969/j.issn.1000-3428.2009.24.091
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problem of the complicated objects of Store Management System(SMS) and the multiple information interacted with SMS, this paper builds use case model of system. It applies the advanced use case modeling to the requirement analysis of SMS. According to the frame of advanced use case modeling, it introduces the specific implement course of advanced use case modeling, and presents some use case model of SMS. The use case model can seize the function requirement of SMS effectively.
  • WANG Lin; WANG Yi-huai
    Computer Engineering. 2009, 35(24): 274-276. https://doi.org/10.3969/j.issn.1000-3428.2009.24.092
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper presents a solution which can conquer reading instability lead by the high voltage on Flash memory array, it is for Freescale UF32 Flash memory In System Program(ISP) of Flash memory in user mode. The method follows modularization thought and encapsulation principle in embedded software engineering, designs universal erase and program subroutines. Example proves that this method resolves the stability problem of Flash memory in system program, and has strong universal property and expediently programming.
  • YU Qiu-dong; XU Hui
    Computer Engineering. 2009, 35(24): 276-277. https://doi.org/10.3969/j.issn.1000-3428.2009.24.093
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper compares the common estimation method with Use Case Point(UCP) estimation method, summarizes the estimation methods of software development in telecom industry, and use UCP estimation method applied to telecom industry to estimate the work load. It expounds how to apply UCP estimation method to the estimation process improvement of the companies in telecom industry. Statistical result shows that this method significantly improves the accuracy of calculate work load.
  • ZHANG Feng-jun; CHENG An-chao; YE You-sun
    Computer Engineering. 2009, 35(24): 278-279. https://doi.org/10.3969/j.issn.1000-3428.2009.24.094
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Simulation is an effective method to study planning and application of Short Wave(SW) communications network. This paper proposes SW network simulation platform based on High Level Architecture(HLA) and network simulation software OPNET after studying foreign military communication network simulation system. It plans main constitute and work flow of the platform, analyzes some key technologies related to developing. Result proves that the development of this platform favors to optimize resource allocation and performance analysis of SW communications network.
  • CHEN Wei; YU Xu-chu; WANG He
    Computer Engineering. 2009, 35(24): 280-封三. https://doi.org/10.3969/j.issn.1000-3428.2009.24.095
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Due to the lack of priori knowledge, it is difficult to determine the number of endmembers for hyperspectral imageries. Aiming at this problem, this paper proposes a new method of estimating virtual dimensionality, its results can be used to estimate the number of the endmembers. Based on the principle of Orthogonal Subspace Projection(OSP), this method extracts and separates the endmember signals, estimates the number of endmembers by comparing the residual value and threshold. Experimental results prove that it is feasible to estimate the number of hyperspectral and PHI hyperspectral image data and it is more flexible and accurate than Nerman-Pearson method.
  • SUN Yong; LIN Fei
    Computer Engineering. 2009, 35(24): 282-284. https://doi.org/10.3969/j.issn.1000-3428.2009.24.096
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    By the refactoring technology in software engineering, this paper proposes a system refactoring model based on abstract data view. It uses the method which combines abstract data view and classic refactoring stragy, and transforms Web applications into Rich Internet Application(RIA) program by reflection approach smoothly. Experimental results show that the model promotes the quality and usability for user interface, and reduces the workload of the process for design and development.