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05 May 2008, Volume 34 Issue 9
    

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  • WEI Bin; WU Chong-qing; SHEN Ping
    Computer Engineering. 2008, 34(9): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2008.09.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The data traffic in the Internet is self-similar. In order to realize the control, management and grooming of the data traffic efficiently, the traffic self-similarity should be gained as fast as possible. Base on the analysis of the self-similar data traffic and the characteristics of the methods including wavelet, EMD and R/S, a fast computation process with high precision is put forward for all kinds of online monitoring, flow control and routing arbitration.
  • XIE Yong-hua; LIU Chuan-cai; YANG Jing-yu
    Computer Engineering. 2008, 34(9): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2008.09.002
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    A human face feature extraction and recognition algorithm based on Divided Discrete Cosine Transform(DDCT) and Singular Value Decomposition Threshold Compression(TCSVD) is proposed. With this method, the human faces are divided into different sub-images and transformed with DDCT, and different high and low frequency coefficients are chosen to construct DCT feature matrix. TCSVD algorithm is used to extract the ultimate discriminative features. And the features are classified with the feature classifier. Experimental results on AR face database validate the efficiency of the method.
  • TONG Ming; JI Hong-bing; LIU Xiao-jun
    Computer Engineering. 2008, 34(9): 7-9. https://doi.org/10.3969/j.issn.1000-3428.2008.09.003
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    This paper puts forward a new audio information hiding algorithm, namely partial phase division correcting method based on hearing perception experiments of wideband audio signals, which is for partial phase distortion conditions under no hearing perception difference. Compared with the classical audio information hiding algorithms, theoretical analysis and experiment results show the effectiveness of this algorithm because of its using partial phase information to assure the auditory comparability. It enhances the embedded magnitude and improves the PER.
  • XIA Wei; LI Zhao-hui; CHEN Zeng-qiang; YUAN Zhu-zhi
    Computer Engineering. 2008, 34(9): 10-12. https://doi.org/10.3969/j.issn.1000-3428.2008.09.004
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    For Bluetooth worm propagation, a determining factor is moving velocity of smart phone in mobile environment. In some works velocity of all nodes is assumed equality. This paper adopts the method of velocity subsection to simulate the variety of nodes moving velocity in Bluetooth communication. According to the propagation characteristics of smart phone virus in Bluetooth environment, it builds an epidemic model that characterizes the propagation dynamics of Bluetooth worms based on velocity subsection. Simulation results show that the epidemic model is closer to real mobile phone network with Bluetooth communication.
  • XUN Zhao-yong; LIAO Jian-xin; CAO Yu-fei; WANG Chun; ZHU Xiao-min;
    Computer Engineering. 2008, 34(9): 13-15,3. https://doi.org/10.3969/j.issn.1000-3428.2008.09.005
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    This paper indicates the problems existing in the present solutions of early-media services, by analyzing the service interoperability between Multimedia Ring Back Tone(MRBT) service and Multimedia Ring Tone(MRT) service, based on IMS(IP Multimedia Subsystem) network. Meanwhile, an early-session based extension means is proposed, which can support multiple early media services simultaneously in the same IMS call instance. The call control models of IMS endpoint are given.
  • FANG Lei; WANG Hong-yuan; XU Fan; TIAN Wen
    Computer Engineering. 2008, 34(9): 16-18. https://doi.org/10.3969/j.issn.1000-3428.2008.09.006
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    The method is based on the reconstruction unit of three views. To avoid the complex computation of trifocal tensor, a simple strategy is presented. After that, a global feature matching process is taken. And a parallel hierarchical method to combine correspondences is used. For a sequence of size n, the traditional method needs (n-1) combinations and (n-1) layers, while the method presented needs (n-2) combinations and lb(n-1) layers, in each layer the combinations are parallel.
  • XIU Yan; MA Jun-hai
    Computer Engineering. 2008, 34(9): 19-21. https://doi.org/10.3969/j.issn.1000-3428.2008.09.007
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    An add-weighted one-rank local-region linear prediction model is generally required by using the least squares method to predict the chaotic time series. A local-region linear prediction method based on Radial Basis Function Neural Net(RBFNN) is presented for chaotic time series prediction, which theory foundation is add-weighted one-rank local-region single-step method. The prediction method is built by using RBFNN substitute for add-weighted one-rank model. The Logistic map and the three axes of Lorenz system are applied to verify the method. Simulation results indicate that the method is effective for the prediction of chaotic time series.
  • YANG Li; XU Yang
    Computer Engineering. 2008, 34(9): 22-24. https://doi.org/10.3969/j.issn.1000-3428.2008.09.008
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    According to the formal context which the construction of concept lattice depends on, this paper gives the definitions of attribute spaces of object and object spaces of attribute, and adopts the objects reduction and attributes reduction in formal context. In the process of reduction, three reduced methods are presented, and based on the reduced formal context, the reduced concept lattice is constructed. A complete concept lattice is to be obtained through the different reparation methods. The method has the characteristics of regularization and simplification. Example expresses that reducing the object and attribute at the rate of 38% for a more complex formal context, the operation efficiency can raise 83.3%.
  • GE Guang-tao; SANG En-fang; LIU Zhuo-fu; GAO Yun-chao
    Computer Engineering. 2008, 34(9): 25-27. https://doi.org/10.3969/j.issn.1000-3428.2008.09.009
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    A method for the image compression of the first residue in the Bidimensional Empirical Mode Decomposition(BEMD) is introduced. It explains the several concepts such as the first IMF, the first residue and the first local mean, respectively compresses the several mean surfaces by representing them with the grid characteristic points, and gets the high quality reconstruction of the first residue surface(image) by adding the several reconstructed mean surfaces together. Experiments prove that the novel method has obvious advantages on the issue of compressing the low frequency information of one digital image compared with the current methods.
  • LU Yang; HE Xin; DU Juan-juan
    Computer Engineering. 2008, 34(9): 28-29,3. https://doi.org/10.3969/j.issn.1000-3428.2008.09.010
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    Case retrieval is an important issue of the Cased Based Reasoning(CBR). To improve the accuracy of case match with inadequacy information, the grey relational analysis is employed to calculate the case similarity, and the computation formula of grey relational degree is ameliorated. A new case retrieval algorithm based on two-step search strategy is proposed. The comparison of the different retrieval algorithms is reported. The result shows that this method has high discernment, and overcomes the limitation of the traditional method, which has more subjectivity in deciding the similarity coefficient.

  • FENG Ying; WU Cheng-ke
    Computer Engineering. 2008, 34(9): 30-32. https://doi.org/10.3969/j.issn.1000-3428.2008.09.011
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    Based on characteristics of the macroblock mode in SVC spatial enhancement layer, a new algorithm is proposed. The algorithm synthetically utilizes the inter-layer prediction information and motion information of temporal direct mode to select the macroblocks that use temporal direct prediction mode to encode motion information. And the macroblocks according with the conditions recovers the motion vectors with temporal direct mode. Simulation result indicates that the proposed algorithm can increase the PSNR by 0.23 dB of enhancement layer, with slightly increasing of the computational complexity
  • ZHANG Yue; QIU Xue-song; MENG Luo-ming
    Computer Engineering. 2008, 34(9): 33-35. https://doi.org/10.3969/j.issn.1000-3428.2008.09.012
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    This paper analyzes the scenarios of business process distribution in distributed coordination. According to the requirements of business process distribution, a process distribution service is defined to distribute business process definitions between coordinators. A model using the process distribution service is given to facilitate distributed coordination between network management systems. The definition of the process distribution service is simple and it is independent of business process description languages. With the process distribution service, the distributed coordination is more efficient.
  • LIU Jie; LI Jian-hua
    Computer Engineering. 2008, 34(9): 36-38. https://doi.org/10.3969/j.issn.1000-3428.2008.09.013
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    This paper investigates a digital signature scheme with message recovery, which is claimed to resist forgery attacks without hash functions and message redundancies. Some attacks and an effective improvement on this scheme are analyzed. A further improvement to shorten the signed signature is presented. The improvement keeps the security properties and makes the scheme more efficient. When and , the improved length of the signed signature is only 44% of the original, which raises computation efficiency by 61% and communication efficiency by 56 %.
  • WANG Guo-jun; WANG Qiong; SHI Rong-hua
    Computer Engineering. 2008, 34(9): 39-41. https://doi.org/10.3969/j.issn.1000-3428.2008.09.014
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    Distributed authentication scheme has high security among the existing authentication schemes for Mobile Ad-Hoc Networks (MANETs). However, its success ratio for authentication is low, especially in large-scale MANETs. In order to tackle this problem, this paper proposes a hybrid authentication scheme which combines distributed authentication with chained authentication. The scheme uses the distributed authentication for managing certificates, and the chained authentication for authenticating the corresponding nodes. Theoretical analysis shows that, compared with existing authentication schemes, the scheme is more scalable and can increase the success ratio for authentication, without sacrificing the security requirement.
  • ZHANG Nan; QIU Xue-song
    Computer Engineering. 2008, 34(9): 42-44. https://doi.org/10.3969/j.issn.1000-3428.2008.09.015
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    To assist the quality evaluation application of Web services in different phases of whole lifecycle, a tri-dimensional quality of service model is provided, and a few key quality indexes are defined. Based on the QoS model and fuzzy algorithm in fuzzy mathematics, a Web services fuzzy quality evaluation approach is introduced. Also, a prototype is given to verify such a model and evaluation approach. Experimental results support the approach and prove its feasibility and applicability.
  • YAN Jia-bin; LIU Gui-zhong
    Computer Engineering. 2008, 34(9): 45-47,5. https://doi.org/10.3969/j.issn.1000-3428.2008.09.016
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    The selectivity of diffusion direction and the ability of directional diffusion are the main characteristics of anisotropic diffusion filter. Efficient expression of local feature of signal or image is the base of anisotropic diffusion. Traditional gradient expression is always disturbed by noise. This paper defines an intension parameter of image local anisotropy and proposes a novel diffusion model by analyzing image local structure expression manner. The results of tests indict the proposed method possesses better abilities of de-noising and directional diffusion, compared with ALM model and CAZ model, and signal-noise ratios improves by 0.1 dB~0.8 dB and 0.3 dB~1.2 dB respectively.
  • Software Technology and Database
  • ZHANG You-sheng; LI Xiong
    Computer Engineering. 2008, 34(9): 48-49,5. https://doi.org/10.3969/j.issn.1000-3428.2008.09.017
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    Software architecture is important in stability, maintenance and evolution of software. This paper introduces component operations to descript software architecture, analyzes the component relativity and component complexity, and synthesizes various factors by using the optimal performance method to adopt the relations of components and design the optimal performance of software architecture. This method can conduct developers to design software architecture in developing software, and the result shows that the software architecture by this design method is optimal for the system.
  • SUN Yan; LUO Xiao-pei
    Computer Engineering. 2008, 34(9): 50-51,5. https://doi.org/10.3969/j.issn.1000-3428.2008.09.018
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    In order to assure the quality of vast survey data on geography data which must meet the requirement of spatial database building, the paper designs a normative, universal, automatic, efficient software , through checking rule checking scheme, checking template, checking task and RSTT model. A configurable and projectable resolution is carried out which support dynamic configuration of checking project, all of check type will be supported in theory.
  • LV Kun; ZENG Qing-liang; WAN Li-rong; ZENG Qing-tian; LIU Zhi-hai
    Computer Engineering. 2008, 34(9): 52-54. https://doi.org/10.3969/j.issn.1000-3428.2008.09.019
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    In the developing process of ontology engineering from pure theory to application research, the definition of ontology is too obscure and enormous to facilitate to construct, share, and reuse. Driven by the requirements on current research and application, a new definition of ontology that focuses on a domain is proposed. To unify the ideas of ontological hierarchy and modularization. Sub-ontology, atom ontology, and the recursive definition of ontology are made under summarization of the existing results. These efforts build a foundation for ontology to form the scientific taxonomic system and consistent logical theory.
  • YANG Xin; YANG Wei-kang; CHEN Rong; SHI Lei;
    Computer Engineering. 2008, 34(9): 55-57. https://doi.org/10.3969/j.issn.1000-3428.2008.09.020
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    WINE virtual machine is analyzed and the reasons of its slow server are pointed out. The concept of Platform Abstraction Layer(PAL) is proposed, and a process virtual machine Elavm is designed and implemented. On Linux, Windows and WinCE, the hardware abstraction, operating system abstraction and device driver abstraction within Elavm PAL are finished. The operating system abstraction includes a general virtual kernel, a set of system calls with high performance and a “busy-wait” inter-process synchronization mechanism based on shared memory. Test results show the average responding time of PAL-based virtual machines is about one thousandth of WINE-like virtual machines.
  • ZHOU Bing; WANG He-xing; WANG Cui-rong
    Computer Engineering. 2008, 34(9): 58-60. https://doi.org/10.3969/j.issn.1000-3428.2008.09.021
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    The hierarchical clustering is an important method of clustering analysis. This kind of method can decompose the datum into different levels, and support people with an understanding procedure from superficiality and generality to detail and specific. A new hierarchical clustering method based on GiST-tree is proposed, which can store the structure of the tree generated during the clustering procedure into the hard disk. So it can support very detailed analyzing procedure. The users can discover the relationship among clusters conveniently with this method.
  • HAN Lin; ZHAO Rong-cai; YAO Yuan
    Computer Engineering. 2008, 34(9): 61-63. https://doi.org/10.3969/j.issn.1000-3428.2008.09.022
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    Computation and data decompositions are key factors of parallel compiler on distributed memory parallel computers. In the process of parallel recognition, many serial codes have no way to find a uniform decomposition result. This paper presents a dynamic decomposition algorithm based on merging control flow analysis. This method, based on the former researches, enhances the influence of control flow to the decomposition and makes the result more suitable for the execution of parallel codes generated by end. Experimental analysis shows the method is effective.
  • SONG Yi; GUO De-feng
    Computer Engineering. 2008, 34(9): 64-66. https://doi.org/10.3969/j.issn.1000-3428.2008.09.023
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    This paper analyzes Chinese full-text retrieval technologies based on compressed inverted file, including data compression, file storage, searching and ranking mechanisms. A Chinese text retrieval simulation system is implemented in C++/STL with ICTCLAS, which is a high precision Chinese segmentation tool from CAS. Some key codes are also included, and an experiment is carried using data provided by the Sogou Lab. The system disk utilization goes up nearly 80% through using improved compression algorithm.
  • BAO Sheng-li; ZHONG Yong
    Computer Engineering. 2008, 34(9): 67-69. https://doi.org/10.3969/j.issn.1000-3428.2008.09.024
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    Based on MVC design pattern, this paper discusses the composition and mechanism of Struts framework, generalizes its characteristic and development steps. Through analyzing and comparing other several development patterns based on Struts framework, it introduces a new Web development pattern combined with Struts framework and procedure. Combining one concrete application case, how to develop Web applications by using Struts framework and procedure is studied.
  • DUAN Dan; GUO Shao-zhong; ZHEN Tao; LIU Xiao-nan
    Computer Engineering. 2008, 34(9): 70-72,7. https://doi.org/10.3969/j.issn.1000-3428.2008.09.025
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    Aiming at the requirement of the massive e-mail data processing and the practical operation demand, this paper designs and implements a massive e-mail classification system based on database programming language, which consists of feature study module, database query module and Bayesian classification module. Combined with the Bayesian classification technology, it makes use of efficient PL/SQL language to extract and express the e-mail feature during the ORACLE PL/SQL stored procedure. It implements the classification of massive e-mail data accurately and efficiently.
  • YAN Wei-feng; LI Sheng-qi
    Computer Engineering. 2008, 34(9): 73-75. https://doi.org/10.3969/j.issn.1000-3428.2008.09.026
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    This paper describes a schema-based data management framework which uses a layered architecture and a Global-As-View(GAV) approach to semantically integrate distributed heterogeneous XML and RDF data sources. Composition of the layered architecture, mapping process and query processing are discussed. The experimental results show that the framework is feasible.
  • ZHANG Jun; CHEN Kai-ming
    Computer Engineering. 2008, 34(9): 76-77,8. https://doi.org/10.3969/j.issn.1000-3428.2008.09.027
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    For reducing the spaces of rule database and facilitating users to query, the minimal prediction set is used and mined using maximum frequent item sets which are found by a set-enumeration tree. The effectiveness of rule expansion is proved in theory. Experimental results show that it is efficient to reduce 1 order of the traditional one.
  • MA Ting-huai; TANG Mei-li
    Computer Engineering. 2008, 34(9): 78-80. https://doi.org/10.3969/j.issn.1000-3428.2008.09.028
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    The purpose of Privacy Preserving Data Mining(PPDM) is discovering accurate patterns and perfect results without precise access to the original data. The requirements of PPDM are put forward. Based on data hiding, PPDM methods are divided into three types: SMC, anonymization and data distortion, and they are evaluated under accuracy, privacy and complexity.
  • BAO Hai-chao; YANG Gen-qing; LI Hua-wang
    Computer Engineering. 2008, 34(9): 81-82. https://doi.org/10.3969/j.issn.1000-3428.2008.09.029
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    The software on small satellite is becoming more complicated and needs the support of Operating System(OS). This paper describes what kind of OS satellite software required and presents a micro kernel structure for satellite embedded system with the characteristics of satellite application oriented, small size, software reconfigurable, high real-time and stability.
  • PENG Jian; XIE Gang
    Computer Engineering. 2008, 34(9): 83-85. https://doi.org/10.3969/j.issn.1000-3428.2008.09.030
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    When developing Extensible Firmware Interface (EFI) applications, the native file system of EFI can not support various file systems. This paper analyses the structure and the component of EFI file system and puts forward a 3-layer model for EFI NTFS file system scheme according to the features of EFI file system. How to implement EFI file system in the form of EFI dirver is introduced and the basic functions of NTFS are implemented on the EFI .
  • LU Peng; LIN Xue-lian; WANG Bin; LIU Li
    Computer Engineering. 2008, 34(9): 86-88. https://doi.org/10.3969/j.issn.1000-3428.2008.09.031
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    At present the tightly coupled communication paradigm can no longer meet the needs of development of large scale E-government applications. And it needs a loosely coupled information interchanging infrastructure to support development of E-government applications. Publish/Subscribe middleware is an effective technology to settle this problem. Based on the client/network architecture, the Publish/Subscribe middleware system Xinfo is presented. Its main framework is put up with key component. A message routing algorithm for broker network is also presented. The result of testing Xinfo system in real application scenario shows that it is the effective technology to settle the problem which is loosely coupled communication among large scale E-government applications.
  • TANG Lei; YANG Zhi-yi; ZHOU Xing-she; ; WANG Tao
    Computer Engineering. 2008, 34(9): 89-92. https://doi.org/10.3969/j.issn.1000-3428.2008.09.032
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    The current multiple-cluster system with different management systems can not support resource sharing, collaborative work and self-adapting management. To settle this problem, a heterogeneity multi-clusters system is established based on the grid technologies, with unified scheduling by resource management middleware which enables the features of resources sharing, dynamic allocation of resources, strong security, and good fault tolerance. The running result indicates that heterogeneity multi-clusters system can run safely and efficiently and the grid based middleware is practical.
  • REN Jie; YANG Xin; SHI Lei; CHEN Yu; YANG Wei-kang
    Computer Engineering. 2008, 34(9): 93-94,9. https://doi.org/10.3969/j.issn.1000-3428.2008.09.033
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    The architecture of the C compiler OCC is introduced. The Abstract Syntax Tree(AST) served as the intermediate representation, of which the 86 different nodes are grouped into 8 categories and the coupling degree of the semantic analysis with the visitor design pattern is reduced. The memory leak problem during the dynamic allocation and destruction of abstract syntax tree nodes is solved using a simple garbage collector. A type builder module gives 7 different treatments to 9 parts of the type specification, which ease the maintenance problem of the attribute grammar script.
  • LI Yi-yong; SHEN Huai-rong; JIANG Xin-xiao; DING Zhe-feng
    Computer Engineering. 2008, 34(9): 95-97. https://doi.org/10.3969/j.issn.1000-3428.2008.09.034
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    The research problem of the intelligent infomation treatment software is introduced based on practical requirements of antiaircraft intelligence & command system. The logical framework of this system and function demands of this software is analyzed. The software is divided into four modules and designed. Furthermore, key technologies related with the software are discussed. The software is implemented, and lots of technology problems, such as changing the secret keyword dynamically, are taken. The software well solves many problems, such as information’s automatic building, transmission, treatment and marking, integrated situation display, and so on. It meets multi-nodes, multi-levels, distributed net structure requirements of antiaircraft intelligence & command system, and ensures the whole system to be finished successfully.
  • ZHOU Yan-tao; YI Xing-dong ; WU Zheng-guo
    Computer Engineering. 2008, 34(9): 98-100. https://doi.org/10.3969/j.issn.1000-3428.2008.09.035
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    By means of calculating density threshold data, some effective referential parameters are worked out and provided for users, and a new kind of clustering algorithm called GRPC is presented. With the help of these referential parameters, it not only can cluster general data but also segregate high-density clusters from low-density clusters. The problem of lower quality of clusters of using traditional grid clustering algorithm is solved when the distribution of data on partitioning grid is usually ignored. Experimental results confirm that this new algorithm can differentiate between outliers or noises and discover clusters of arbitrary shapes, with good clustering quality.
  • ZHENG Jiao-ling
    Computer Engineering. 2008, 34(9): 101-102,. https://doi.org/10.3969/j.issn.1000-3428.2008.09.036
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    By developing Wen-Syan Li’s website logical domain theory, the paper proposes a website logical domain core model and logical domain mining algorithm based upon it. The algorithm computes website’s hyperlink graph structure to obtain its logical domain. In comparative test with Wen-Syan Li’s algorithm, it overcomes the efficiency defect of Wen-Syan Li’s huristic method while obtaining the same quantity of logical domain. In separate test of 4 large scale websites, the logical domain core mining precision can averagely reach 85%.
  • WANG Xiao-cheng; LI Juan; YU Fang;
    Computer Engineering. 2008, 34(9): 103-105. https://doi.org/10.3969/j.issn.1000-3428.2008.09.037
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    Existing simplified Function Point Analysis(FPA) methods have different effect among different software individuals, especially when applied to the small-to-medium-sized software, which may result in larger result. This paper proposes a simplified function point analysis method based on NESMA indicative method, aiming at the small-to-medium-sized software. Experimental results show that the proposed approach is more accurate than other simplified methods when applied to this kind of software.
  • WANG Ming-fu
    Computer Engineering. 2008, 34(9): 106-108. https://doi.org/10.3969/j.issn.1000-3428.2008.09.038
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    A new algorithm for finding the critical paths is proposed by using coding graph and without topological sort. By extending the data structure of the adjacency lists in the graph, the graph is stored in the same storage space with the algorithm. Beginning from the source node of the graph, by using the rule of getting the maximum number in the weighing calculation and breadth-first search, it encodes all nodes in the graph recursively. That recursively accessing the adjacent node and starting from the current node is the process of re-estimation about preceding node set and the length value from the adjacent node to the source node. After creating the coding graph, by inversing search, it can find all critical paths and the length from destination node to source node. Compared with the traditional algorithms, the algorithm proposed is simpler, more understandable and needs less storage space. The time complexity is O(n+e), which is lower than O(n2) of the traditional algorithm.
  • LIU Yu; LV Zhi-peng; LUO Fei
    Computer Engineering. 2008, 34(9): 109-111. https://doi.org/10.3969/j.issn.1000-3428.2008.09.039
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    By analyzing the algorithm of PERM based on the lattice model, a strategy of how to parallelize PERM is introduced. The strategy stores the average weight vector, the most important part in PERM, as the middle information and distributes this information to several computing cells for some simulation computing. So it can improve the speed of computing and achieve the more accurate results. P2P-based High Performance Computing Platform(P2HP) is employed as the experimental environment. Some different protein sequences are computed. The results of experiment show the parallel computing method based on PERM can achieve the better performance on P2HP.
  • QIU Yun-fei; SHAO Liang-shan; NA Bao-gui
    Computer Engineering. 2008, 34(9): 112-113,. https://doi.org/10.3969/j.issn.1000-3428.2008.09.040
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    Aiming at the data island in the management information system, this paper introduces the principle of share data warehouse, integrates the data from information system using DTS to complete the function of ETL, and loads these data into an integrated data warehouse, satisfying the requirements of data storage, query, statistic etc. It realizes whole Enterprise Resource Planning(ERP). It gives a method to call the DTS package under B/S scheme and the whole structure of the scheme and part of key code.
  • Networks and Communications
  • CHEN Zhuo; LI Yin-guo; WANG Tian
    Computer Engineering. 2008, 34(9): 114-115,. https://doi.org/10.3969/j.issn.1000-3428.2008.09.041
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    Most Ad Hoc routing protocols select route based on shortest path mechanism, which does not take network load into consideration. This paper puts forward an adaptive dispersive mobile Ad Hoc routing protocol, namely ADMAR, which is based on the traffic load of the network node. The simulation shows that the routing protocol has good stability, can distribute the traffic load of Ad Hoc network to some extend, and reduces the network hotpots.
  • SUN Li-jun; WANG Li-hong; LU Zhao-yi
    Computer Engineering. 2008, 34(9): 116-118. https://doi.org/10.3969/j.issn.1000-3428.2008.09.042
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    This paper proposes a novel RED algorithm based on multiple priorities namely Preferential Dynamic Threshold-RED(PDT-RED). It can adjust dynamically average queue length thresholds respect to packets’ priority and unused buffer space, and realize differentiated services. On the basis of PDT-RED, an optimized scheme ——OPDT-RED is presented. Compared with RED, OPDT-RED can reduce loss rates of packets with higher priority by 56%~62% and the average loss rates of all packets by 33%~41%. It is easy to implement, and satisfies higher buffer utilization.
  • ZHOU An-fu; LIU Min
    Computer Engineering. 2008, 34(9): 119-120,. https://doi.org/10.3969/j.issn.1000-3428.2008.09.043
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    This paper presents a self-adaptive silence suppression algorithm. The algorithm can adjust its suppression threshold to current yawp environment. It can save about 50% bandwidth of VoIP session. The algorithm is especially useful under low bandwidth network environment such as CDMA. It can reduce network congestion and improve QoS of VoIP. The experiments demonstrate the algorithm’s effect.
  • QIU Meng; XU Hui-min
    Computer Engineering. 2008, 34(9): 121-123. https://doi.org/10.3969/j.issn.1000-3428.2008.09.044
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    Localization algorithm is the key technique of wireless sensor networks. This paper presents a range-free distributed algorithm consists of scale-localization algorithm and improved controllable flood. By using scale-localization algorithm, nodes can realize localization based on anchor positions and the least hops to the anchors without average hop size. Improved controllable flood can keep the same amount of packets as traditional one and enhances precision. Simulation by OPNET shows that precision of radio range increases to 20%.
  • LI Jin-ling; SU Xiao-yun; ZHANG Chen; FENG Chun-yan
    Computer Engineering. 2008, 34(9): 124-126. https://doi.org/10.3969/j.issn.1000-3428.2008.09.045
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    On the basis of analysis of rerouting scheme for MPLS network, a new method of computing backup path is advised, where the computation of backup path is divided into two steps: pro-processing and on-line processing. Based on the new method, a Fundamental Circuit Rerouting(FC-R) scheme is proposed. Simulation results and analysis show that FC-R has many advantages as follows shortening recovery time, increasing resource utilization, supporting link failure and node failure, and saving the time in on-line computing.
  • LI Bin; LI Wen-feng
    Computer Engineering. 2008, 34(9): 127-129. https://doi.org/10.3969/j.issn.1000-3428.2008.09.046
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    Wireless Sensor Network(WSN) changes human being and the nature interactive mode, and radio frequency identification puts up the bridge between the physics world and current information system. If WSN and RFID and connect with IEEE802.15.4 and ZigBee, people will get WSID network, that has great improvement in the respect of communication distance, clock synchronism, localization and data aggregation, etc. relative to available WSN and RFID. The paper brings forward the software platform architecture based on Service-Oriented Architecture(SOA) and XML Web Services according to the applied characteristic of the omnibus system.
  • ZHANG Hui-dang; HE Yu-yao; JIANG Wen
    Computer Engineering. 2008, 34(9): 130-132. https://doi.org/10.3969/j.issn.1000-3428.2008.09.047
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    This paper presentes a new algorithm based on chaotic controlled quantities to optimize the multicast tree with delay bound. The proposed Chaotic Neural Network(CNN) can control network energy to increase, decrease or keep unchanged through chaotic controlled quantities added to each neuron, which can help neural network to enlarge searching space to get optimal solutions and avoid local minima or invalid solutions. The energy function is also defined to represent the cost of optimal path with the delay bound. Comparing the results with the other algorithms, results show that the proposed algorithm is both efficient and effective in constructing the optimal delay bound multicast tree.
  • LIU Yuan-tao; GE Lin-dong; WANG Bin
    Computer Engineering. 2008, 34(9): 133-135. https://doi.org/10.3969/j.issn.1000-3428.2008.09.048
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    For many blind channel estimation algorithms based on second-order statistics, knowledge of the channel order has to be available. In light of the fact that the noise power is affected by the change of the channel order, a novel algorithm is proposed. The proposed algorithm, compared with conventional algorithms, is proved to be of low computation complexity and can work well under low SNR and small set of data. In addition, the new algorithm is independent of the concrete blind channel estimation methods.
  • XIAO Liao-liang; ZHAO Kai-hui ; DENG Mu-sheng
    Computer Engineering. 2008, 34(9): 136-138. https://doi.org/10.3969/j.issn.1000-3428.2008.09.049
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    NAT-PT is a key technology to implement intercommunication between IPv4 and IPv6, but the single NAT-PT has some defects. This paper proposes NAT-PT cluster to solve the problems of the single NAT-PT. The hardware structure uses DNS-ALG as the schedule center and three layer structure software system is designed. The schedule strategy which combines extended weights round robin algorithm with dynamic threshold algorithm is presented. The relevant experiments prove that the software and hardware structures as well as the schedule strategy are the right resolution for overcoming the defects of single NAT-PT.
  • ZENG Wen; WANG Hong; XU Ai-dong
    Computer Engineering. 2008, 34(9): 139-141. https://doi.org/10.3969/j.issn.1000-3428.2008.09.050
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    This paper applies ultra wideband technology to industrial wireless monitoring network, analyzes characteristics of impulse-radio-based ultra wideband technology, such as low complexity and low cost. It is resistant to severe multi-path and jamming, and has good positioning. Synchronization and positioning problems are discussed, and key ideas and solutions are proposed for Media Access Control(MAC) protocol. Simulations show validity of the solutions.
  • FAN Jing; GAO Fei; WANG Wan-sheng; CHEN Yue-bin;
    Computer Engineering. 2008, 34(9): 142-144. https://doi.org/10.3969/j.issn.1000-3428.2008.09.051
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    Based on the protocol of IEEE 802.11 for wireless Ad Hoc networks, the Distributed Coordination Function (DCF) of Ad Hoc networks is modified, and an adaptive minimum contention window binary exponential backoff algorithm namely ABEB is present. The bidimensional discrete-time Markov chain model for ABEB algorithm is established, and the stationary distribution probabilities of the algorithm are educed. The performance of the algorithm is analyzed, and the algorithm is simulated. Compared with DCF algorithm, the study results show that the throughput of ABEB algorithm increases by 18% while the access delay decreases by 11% on average.
  • WEN Ge; WANG Guo-jun
    Computer Engineering. 2008, 34(9): 145-147. https://doi.org/10.3969/j.issn.1000-3428.2008.09.052
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    This paper focuses on the coverage issue in randomly deployed Wireless Sensor Networks(WSNs) and proposes a Voronoi diagram-based distributed coverage protocol. The protocol adopts a distributed eligibility algorithm for detecting redundancy of sensor nodes and scheduling their duties accordingly. It can achieve both coverage and connectivity when the communication range of sensor nodes is at least twice the sensing range of sensor nodes. It is extended to maintain k-coverage to handle the case of dynamic change of coverage degree.
  • MENG Xian-fu; WANG Ying-chun; SHI Lei
    Computer Engineering. 2008, 34(9): 148-150. https://doi.org/10.3969/j.issn.1000-3428.2008.09.053
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    A routing querying scheme that can adapt to the extension of network is proposed to attack the problem of blind routing in P2P search. During the course of searching, the information of every replying node is saved in route tables of its two neighborhood nodes respectively according to the responding order, and which is used to guide the following routing. Initial neighborhood node is chosen to route in case of no information available, which makes use of the characteristics of the initial topology. Experimental results manifest that the scheme can reduce the number of messages in the network and improve searching performance effectively.
  • Security Technology
  • GAO Xiu-feng; CHEN Li-yun; HU Chang-zhen
    Computer Engineering. 2008, 34(9): 151-153. https://doi.org/10.3969/j.issn.1000-3428.2008.09.054
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    Intrusion process consists of a series of intrusion behavior, which comprises one or some intrusion events. There are various relations among these intrusion events. Intrusion characteristic is studied, and intrusion events are classified by those aspects of intrusion. By defining intrusion event, common model of intrusion events is established. Based on analysis of time relations, space relations and function relations among intrusion events, the logical model, statistical model and fuzzy model are established. With these models, intrusion behavior can be represented. And it is testified by instance.
  • XU Yan-yan; XU Zheng-quan; LI Mao-quan
    Computer Engineering. 2008, 34(9): 154-156. https://doi.org/10.3969/j.issn.1000-3428.2008.09.055
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    An efficient and low-latency conference key management scheme is proposed. With this scheme, the problem of low efficiency in data transmission in existing de-centralized schemes is solved, and the data latency is reduced. Based on this, this paper presents the system modeling and the scheme on how to divide the group to get the minimum rekey cost and the optimal bandwidth.
  • CHEN Ming; WANG Zhen-wu
    Computer Engineering. 2008, 34(9): 157-158,. https://doi.org/10.3969/j.issn.1000-3428.2008.09.056
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    The normal Role-Based Access Control(RBAC) model configures the model resources through roles, and this model is one-dimensional according to the manipulated resources. This paper proposes a new conception——visual data muster, gives a three-dimensional access control model——ACBR3D, which is based on role, authorized time and visual data muster, and describes the ACBR3D model. The former constraints are extended so that it can describe the visual data muster character. Compared with other models, this model has many merits such as accuracy, flexibility and small granularity.
  • SUN Jin-xia; LIAO Fu-cheng; TIAN Li-qin; JI Tie-guo
    Computer Engineering. 2008, 34(9): 159-161. https://doi.org/10.3969/j.issn.1000-3428.2008.09.057
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    This paper proposes a new model of user behavior decision-making based on the integration of risk and security. The service provider and the user are regarded as the two players in the non-cooperation games, and their interactions are analyzed based on static games model with incomplete information. The game model is built in the point of view that the players choose their actions depending on each other’s action. The mixed strategy equilibriums are derived from the model, and under the mixed strategy equilibriums, the service provider makes the decision such as refusing access or accepting access which can maximize his utility.
  • MA Bin
    Computer Engineering. 2008, 34(9): 162-163,. https://doi.org/10.3969/j.issn.1000-3428.2008.09.058
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    The definition of risk is one of the most important problems that need to be solved in the application of risk theory in pervasive computing. Cloud theory is an effective tool in transforming between qualitative concepts and their quantitative expressions. This paper uses the concept of cloud theory to estimate dynamic context and presents the definition of risk signal. By integrating various risk signals, the definition of risk is got. A coordinated trust model including both trust model based on cloud theory and risk recognition method is presented. The coordinated trust model to carry on the experiment is simulated.
  • SUN Yun; HUANG Hao
    Computer Engineering. 2008, 34(9): 164-166. https://doi.org/10.3969/j.issn.1000-3428.2008.09.059
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    Intrusion Detection System(IDS) has been harassed by false positive and false negative problem. Common IDS using single detection mode is hard to solve this problem effectively. This paper analyzes the characteristics of network flow and presents a new method, called hybrid IDS, combining misuse detection mode and anomaly detection mode, the method can overcome the shortcomings of IDS using single mode. Experiments show that the new method can improve IDS detection rate and decrease false alerts effectively.
  • WANG Ying; XIANG Bi-qun
    Computer Engineering. 2008, 34(9): 167-169. https://doi.org/10.3969/j.issn.1000-3428.2008.09.060
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    On the studying techniques of the Intrusion Detection System(IDS), this paper develops the IDS model based on the user behavior. The genetic algorithm is applied to the IDS for the accuracy of the pattern warehouse. So it succeeds in combining the IDS and the genetic algorithm. Result of the experiment proves the genetic algorithm is effective and practical.
  • SHI Run-hua; ZHONG Hong; HUANG Liu-sheng
    Computer Engineering. 2008, 34(9): 170-171,. https://doi.org/10.3969/j.issn.1000-3428.2008.09.061
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    This article presents a dynamic multi-secret sharing scheme in any access structure based on Shamir’s secret sharing. This scheme splits and reconstructs the secrets using the method of the Lagrange interpolation. This scheme can dynamically join or delete the participants and dynamically renew multi-secret, without re-distributing the sub-secrets. The sub-secrets are kept secretly by the participants. It is the shadows of the sub-secrets that are submitted by the participants during the reconstruction of the multi-secret. And any party can verify the correctness of the shadows from the public information, thus the sub-secrets can be re-utilized.
  • HAN Jie-si; SHEN Jian-jing; YUAN Yuan
    Computer Engineering. 2008, 34(9): 172-173. https://doi.org/10.3969/j.issn.1000-3428.2008.09.062
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    In the context, the concept of hiding key is defined that it is a function with three elements including K1, the secret key to choose the arithmetic, K2, the secret key to choose the image, and K3, the secret key to choose the positions and sequence of embedding. Based on the analysis of the meanings of K1, K2, and the measurement of the counting complexity of K3, the property of protection from distilling of the information hiding system based on the image is evaluated, and it has instructional significance in the research of the field of security.
  • LIANG Xing-tao; DENG Hui-fang; TIAN Wen-chun; ZHENG Dong-xi
    Computer Engineering. 2008, 34(9): 174-176. https://doi.org/10.3969/j.issn.1000-3428.2008.09.063
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    Because Public Key Infrastructure(PKI) has some defects in its basic theories, a novel authentication technology is urgently required to replace PKI in kinds of security domains. Compared with the PKI-based authentication systems which are widely used at present, Identity-Based Combined Public Key(IBCPK) algorithm has two advantages: validating information immediately and managing large numbers of keys effectively. In this article, IBCPK is presented and a certificate management system based on IBCPK is developed for managing the keys produced in IBCPK system. Additionally, the certificate is designed in a new architecture in order to meet the requirements of the key management in IBCPK system.
  • LI Yan-ping; TANG Zhen-min; QIAN Bo
    Computer Engineering. 2008, 34(9): 177-179. https://doi.org/10.3969/j.issn.1000-3428.2008.09.064
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    Synchronization is one of the key issues of audio watermark. Current audio watermark algorithms lack effective techniques for synchronization. Blind detection is realized with the balance between inaudibility and robustness. Experimental results show the synchronization scheme is low-complex, robust and simple for application.
  • WANG Wen-bing; LI Xiao-yong
    Computer Engineering. 2008, 34(9): 180-182. https://doi.org/10.3969/j.issn.1000-3428.2008.09.065
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    Aimming at separated accounts management in heterogeneous environment, this paper proposes a new solution which bases on a heterogeneous domain——Heterogeneous System Management Domain(HSMD). It solves the conflicts in account storing modes and authentication mechanism of different operating system. With attention to both security and practicability, a perfect unified heterogeneous accounts management platform is implemented. Experimental results show the method is effective.
  • CAI Zhao-quan;
    Computer Engineering. 2008, 34(9): 183-185. https://doi.org/10.3969/j.issn.1000-3428.2008.09.066
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For the trivial design and the complexity of the permission management in software development, human resources are wasting in writing codes of various business functions and complicated authority settings. To solve this problem, a kind of general permission management module using function mask to separate permission controls from concrete business is implemented. This kind of module can be embedded in various systems just by setting function points without rewriting codes. Developers can create roles and users on the module to implement their own permission management.
  • ZHAO Ting; LU Yu-liang; LIU Jin-hong; SUN Hong-gang; SHI Fan
    Computer Engineering. 2008, 34(9): 186-188,. https://doi.org/10.3969/j.issn.1000-3428.2008.09.067
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    This paper proposes an adaptive site-search strategy based on glide window and a navigation link searching strategy based on both location and the frequency of appearance. A new form crawler is designed which is different from common crawler or topic crawler. The form crawler utilizes navigation link to search form. Then a new Web vulnerability detecting scheme is proposed based on the form crawler. It is proved that the harvest and coverage of form searching reaches 24% and 85% respectively, and the accuracy of XSS detection reaches 96%.
  • Artificial Intelligence and Recognition Technology
  • XUAN Xiao; LIAO Qing-min
    Computer Engineering. 2008, 34(9): 189-191. https://doi.org/10.3969/j.issn.1000-3428.2008.09.068
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    Automated MRI brain tumor segmentation provides a powerful tool for diagnosis. In this paper, a tumor segmentation method using multi-feature extraction and AdaBoost feature selection is presented. The method utilizes the information of MR images and the anatomical knowledge, and takes the advantage of the feature selection ability of AdaBoost. Experimental results on 20 slices MR images demonstrate the effectiveness of the feature selection, and achieve an accuracy of 96.82% on tumor segmentation.
  • WANG Jing
    Computer Engineering. 2008, 34(9): 192-194. https://doi.org/10.3969/j.issn.1000-3428.2008.09.069
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    Nonlinear dimensionality reduction is applied to many research fields, including data mining, machine learning, image analysis, and computer vision. Isomap is a global manifold learning approach. It is effective for learning the embedding results of the Isometric manifold, but it is not robust against outliers in the data. This paper proposes an outlier detection algorithm, and gives a global manifold learning approach based on the basic idea of Isomap to make Isomap more robust against outliers. Numerical experiments show the method is effective.
  • CHEN Xin; YIN Dong; ZHOU Zhong-na
    Computer Engineering. 2008, 34(9): 195-197. https://doi.org/10.3969/j.issn.1000-3428.2008.09.070
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    Traditional solo-resolution bridges detection methods turn out to be inefficient when applied to large SAR images. This paper proposes a new method based on multi-scale feature analysis. An algorithm based on dynamic programming is proposed to detect rivers, locate bridge candidates in low resolution level and obtain Regions Of Interest (ROI) in middle resolution level. Bridges are detected by analyzing the ROI. Experimental results indicate that the method can process one scene SAR image (10 000×10 000 pixels) in 15 s, with detecting rate above 90% and false alarm rate less than 5%.
  • WANG Kai-jun; LI Jian; ZHANG Jun-ying; GUO Li-xin
    Computer Engineering. 2008, 34(9): 198-199,. https://doi.org/10.3969/j.issn.1000-3428.2008.09.071
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    Estimation of clusters number is a crucial problem for applying robust Partitioning Around Medoid(PAM) clustering algorithm to gene expression data. This paper discusses seven methods of cluster validation for PAM algorithm and gives their experimental comparison on estimation of the clusters number, using simulated and real gene expression data that hold four different types of cluster structures. Experimental results show that the system evolution method and stability-based method give estimation accuracy of 90% and 100%.
  • LAN Tian-ge; FANG Yong-hua; XIONG Wei; KONG Chao
    Computer Engineering. 2008, 34(9): 200-202. https://doi.org/10.3969/j.issn.1000-3428.2008.09.072
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    Construction of Radial Basis Function Neural(RBFN) networks involves computation of centers, widths of each RBF, and number of RBF in the middle layer. The modified clustering algorithm is used to construct RBFN automatically. The algorithm considers the class membership of training samples, can automatically compute RBF centers and widths, and determines the number of Radial Basis Function(RBF) units based on the distribution of samples. Parameters are optimized with nonlinear optimization technique. The performance of the self-growing RBFN and effects of the optimization are estimated with IRIS classification problem and chaotic time series prediction. The results confirm that self-growing RBFN determines networks structure automatically, and has good performance in pattern recognition and function approximation. Better performance can be observed after nonlinear optimization of networks parameters.
  • YANG Ling-xiang; LI Jun-xia; SHUI Peng-lang
    Computer Engineering. 2008, 34(9): 203-204,. https://doi.org/10.3969/j.issn.1000-3428.2008.09.073
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    This paper proposes a Beamlet-based method for line feature extraction from noisy images. The directional filtering using a set of directional windows is used to highlight the line and curve features along different directions. The thresholding process is used to transfer the obtained gray-level images to a set of binary images and these binary images are fused into a single binary image by the logical ‘or’ operator. The Beamlet transform is applied to the fused binary image to extract the line and curve features in the original noisy image. Experiments show that the proposed algorithm can achieve satisfactory performance in the cases of low signal-to-noise ratios.
  • PAN Zu-lie; SUN Le-chang; CAI Ming; CHEN Jian-xiong
    Computer Engineering. 2008, 34(9): 205-207,. https://doi.org/10.3969/j.issn.1000-3428.2008.09.074
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    The technology of test cases auto-generating based on Genetic Algorithm(GA), software dynamic debugging and static disassembling is introduced. The method for calculating fitness function in GA using dynamic debugging technology is researched. The model for black-box test cases auto-generating based on GA is proposed and designed, by which test cases can be auto-generated according to the executable files without instrumentation for software source code and the application area of test cases auto-generating technology based on GA is extended.
  • CHEN Yu-tuo; WEI Bing; QIU Zi-hua; DING Can-jian
    Computer Engineering. 2008, 34(9): 208-210. https://doi.org/10.3969/j.issn.1000-3428.2008.09.075
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    In view of the characteristic of the complex carving pattern of handcraft drawing, this paper realizes the vectorization of complex carving patterns of handcraft drawing using piecewise cubic Bezier curves. It presents a solution that can adaptively distinguish line patterns and region patterns and extract the boundaries of the region patterns. These boundaries are divided into some independent line segments according to selected corner points. In the curve fitting process, these line segments are further divided according to the offset from the data points of the segment to the curve for enhancing the fitting precision. And a new way of smooth connection of segmented curves is presented. Experimental results indicate that this method has the advantages of lower algorithm complexity and better vectorization effect for vectorization of the complex carving patterns of handcraft drawing, and it has broad practicability.
  • LI Lin-hui; WANG Rong-ben; GUO Lie; JIN Li-sheng; CHEN Bai-chao
    Computer Engineering. 2008, 34(9): 211-212,. https://doi.org/10.3969/j.issn.1000-3428.2008.09.076
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To realize obstacle avoidance path planning for lunar rover, stereo vision technology is applied to precept front environments, and a feature-based obstacle detection method is designed. Histogram-Bug algorithm is presented to realize obstacle avoidance path planning. The world model is described using a polar coordinates histogram. Global convergence is ensured by motion-to-goal behavior and boundary following behavior working together. 3-D reconstruction technologies and simulations confirm the effectiveness of the method.
  • YANG Cui-li; GUO Zhao-hui; WU Gang-shan
    Computer Engineering. 2008, 34(9): 213-215. https://doi.org/10.3969/j.issn.1000-3428.2008.09.077
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    During the process of music genre classification, when dealing with inconsistency between the local genre features and the global genre attribute, the MaxVote method which determines the whole genre by the dominate local genre is not so reasonable when the local feature is distributed uniformly. The paper proposes a method called NNVote based on clip genre distribution feature and a method called RhythmNNVote which combines the high level rhythm feature and low level features. In the experiment, the NNVote method total classification accuracy reaches 68.9% on 7 genres which improves about 10% compared with MaxVote.
  • ZHANG Rui; YU Zhong-dang
    Computer Engineering. 2008, 34(9): 216-218. https://doi.org/10.3969/j.issn.1000-3428.2008.09.078
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    In order to overcome the effect which great illuminative changes have on the recognition rate, a face recognition technique based on Sec-(2D) 2PCA is presented in this paper. It discards principal components of the first several reflective illumination information that are extracted from the original face images with (2D)2PCA method. And then, (2D)2PCA is used again in the surplus images. A series of experiments are performed on face image databases: Yale human face database B and Yale human face database. The experimental result indicates that recognition performance of Sec-(2D)2PCA is superior to that of 2DPCA, (2D)2PCA, Sec-2DPCA method.
  • WANG Hui; WANG Ke-jun; YU Li-jun; Du Zhi-bo
    Computer Engineering. 2008, 34(9): 219-221. https://doi.org/10.3969/j.issn.1000-3428.2008.09.079
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    By analyzing the coverage space of detector set created by the adjustable fuzzy matching negative selection algorithm, aiming at the phenomenon of matching each other between detectors in detector set, this paper brings forward an algorithm of creating minimal effective detector set. This algorithm uses fuzzy thought to determine matching threshold and eliminates redundancy phenomenon in detector set effectively. Simulation results show that space coverage ratio of detector set created by this algorithm increases obviously, and it realizes using smaller detector set to detect nonself action in bigger range, increases detecting ratio and capability of system.
  • GAO Ying-fan; MA Run-bo; LIU Yu-shu
    Computer Engineering. 2008, 34(9): 222-224. https://doi.org/10.3969/j.issn.1000-3428.2008.09.080
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This experiment is based on the category-feature database which includes all features of the training set and three text categorization algorithms: Rocchio, Fast TC and NB. The experiment analyzes quantificationally the effect on effectiveness of text categorization produced by stopwords list, stemming, digital and testing text length. The experimental results show that stopwords list has no effect on effectiveness of TC; stemming has some effect but cut little figure; the correlation of digital and other words of documents makes the effectiveness of Rocchio and TC higher but lower NB and different testing text length describes the effect of beneficial and noisy information on effectiveness of TC. These popular feature selection methods are connected with the result of text categorization tightly.
  • GAO Qing-de; CHENG Ying
    Computer Engineering. 2008, 34(9): 225-226. https://doi.org/10.3969/j.issn.1000-3428.2008.09.081
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    It is a very important field to intelligence analysis system of every nation that psychology recognition combines with artificial intelligence and computer science. The paper studies the key technic of American matrix intelligence analysis system extensively. Arithmetic is discussed in this paper, and it gives the analysis process and the architecture of this system
  • CHEN Yang
    Computer Engineering. 2008, 34(9): 227-229. https://doi.org/10.3969/j.issn.1000-3428.2008.09.082
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    This paper constructs a system structure which is used for conceptual design on the basis of FCBR and AHP. The structure combines the fuzzy set theory with CBR to solve the problem that most design requirements described by users are uncertain and nonstandard. After retrieving the competent evaluation cases set, the system uses AHP method to evaluate the function and economy indexes of the cases set, attains the most appropriate design candidate, and achieves the final optimized scheme by transfering the adaptation rules of the function adaptation cases to modify the design candidate. The application result shows that the hybrid mechanism can provide the designers with effective design decision during conceptual design.
  • Multimedia Technology and Application
  • CHEN Yong-hua; WANG Yi; LIU Dong-hua; ZHOU Jing-ye
    Computer Engineering. 2008, 34(9): 230-231. https://doi.org/10.3969/j.issn.1000-3428.2008.09.083
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    AVS is a domestic audio and video coding standard of China. In its video coding, sub-pixels search method is applied to achieve more accurate motion description and higher compression efficiency, with higher complexity. In order to reduce the complexity, a fast three step sub-pixels search algorithm is presented based on monotonous increase of the distortion of a search point with increasing distance from that search point to the Global Minimum Point(GMP), and the center-biased of motion vector. Simulation results show that the new algorithm can reduce computational complexity by more than 65% with little quality degradation.
  • WU Yuan-bao; LIU Zhen-sheng; ZHANG Wen-liang
    Computer Engineering. 2008, 34(9): 232-234. https://doi.org/10.3969/j.issn.1000-3428.2008.09.084
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    In the Internet, congestion control out of TCP protocol by Additive Increase and Multiplicative Decrease(AIMD) fails to satisfy the need for multimedia communications. To meet the need of multimedia communications in Internet in desirable Quality of Service(QoS), a fresh congestion control mechanism of Study-based Expanded AIMD(SB-EAIMD) rate control with the number of multimedia package loss is put forward in support of the point to point multimedia communication, with detailed research of its operation principle and approaches.
  • LIU Yu; WANG Li; WANG Lei
    Computer Engineering. 2008, 34(9): 235-237,. https://doi.org/10.3969/j.issn.1000-3428.2008.09.085
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    Information of coded video streams is always used by video transcoders to improve the efficiency. This paper suggests a MPEG-2 to H.264 video transcoder. The motion estimation difference between MPEG-2 and H.264 is analyzed and several Motion Vector(MV) refine algorithms are proposed to improve the transcoding quality. Using the suggested MV refine algorithms, the transcoder can generate high quality H.264 videos with low complexity.
  • LU Xing-chang; ZHANG Yan-hong; ZHANG Ai-wu
    Computer Engineering. 2008, 34(9): 238-239,. https://doi.org/10.3969/j.issn.1000-3428.2008.09.086
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Three dimensional points cloud data are analyzed by using object-oriented programmer, and the computer-based realization, which is organized by points cloud data of urban building captured by laser scanning, is studied based on image process on the exploration platform of Visual C++6.0. The unique global indexes of valid target points are determined by scanning relationship between points. The image range corresponding to the global indexes is fixed on by taking points cloud data as a range image. The points cloud data are classified and organized by calculating the normals of all corresponding points by using the image ranges obtained before. The experimental results indicate that loading and organizing three dimensional points cloud data can be implemented easily and quickly by using object-oriented image technique.
  • Engineer Application Technology and Realization
  • LIU Ting; WANG Zhan-lin; QIU Li-hua
    Computer Engineering. 2008, 34(9): 240-242. https://doi.org/10.3969/j.issn.1000-3428.2008.09.087
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Multiprocessor task allocation and scheduling is a key technology of the aircraft Utility Management System(UMS). Dynamic scheduling of hybrid tasks in condition of uncertain instance is carried out by means of combination of static and dynamic condition and of combination of global, local and feedback scheduling. The static scheduling is carried out by the improved immune clone algorithm. Its result is as initial value of dynamic allocation. The dynamic scheduling has the function of detecting, classifying, and adaptive feedback. It is applicable for coexistence of hybrid tasks and variety of task load.
  • SONG Jun; YU Sheng-lin
    Computer Engineering. 2008, 34(9): 243-245. https://doi.org/10.3969/j.issn.1000-3428.2008.09.088
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    The fiber wrap always occurs in the later processing of staple fiber. When it happens, the surface of later fiber brings out some fissures because of lacking of silk. The more silk the roller wraps, the wider the fissure is, and the easier the roller damages. The paper presents a real-time solution based on DSP and machine vision for detecting the fiber wrap accurately in real-time, and also introduces the system hardware platform and software design. In the simulation test, some pictures whose fissure width increases at the speed of 0.67 m/s are detected, and it only takes 156 ms to find out the fiber wrap and send the alarm signal.
  • ZHAO Yong-jian; DUAN Guo-dong; LI Miao
    Computer Engineering. 2008, 34(9): 246-247,. https://doi.org/10.3969/j.issn.1000-3428.2008.09.089
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    During the process of communication between different clock domains, metastability is likely to happen. This paper discusses several applications of different synchronizers in IC asynchronous design. Asynchronous FIFO is applied to the design of asynchronous data buffer between the interface and the core of ATM communication chip. The results of simulation show that the method can increase the reliability as well as realize the desired function.
  • Developmental Research
  • ZHOU Qiao; CHEN Jing-wei; LI Jian-sheng; LAN Chao-zhen; XU Qing
    Computer Engineering. 2008, 34(9): 248-250. https://doi.org/10.3969/j.issn.1000-3428.2008.09.090
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    In allusion to characteristics of the complicated electromagnetic environment on condition of modern times high technology condition, based on the analysis of the requirement of the electromagnetic environment on the condition of information, the paper confirms several basic factors, puts forward the method of constructing the electromagnetic environment using the 3D visualization, realizes the visualization of the electromagnetic environment using direct volume rendering, surface fitting and slice rendering, and makes detailed expatiations on the realizing of methods of visualization and succeeds in realizing the 3D visualization of the analyzing results of regional electromagnetic situation, with the results of the experiments proving that the method is effective.
  • WU Zhi-qiang; KANG Li-gang
    Computer Engineering. 2008, 34(9): 251-253. https://doi.org/10.3969/j.issn.1000-3428.2008.09.091
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    The paper introduces the embedded system, the OpenGL ES basic concept and OpenGL ES programming method based on WinCE operating system. A terrain visualization system is designed, and the system is achieved by using OpenGL ES and Embedded Visual C++ 4.0(EVC). The system is a 3D terrain visualization in embedded system. The system carries out modeling and the dynamic manifestation of terrain, and simultaneously through the roaming function, the texture mapping and the cube sky-box realize the 3D terrain with reality.
  • CHEN Xu-jun; LIU Shou-yin
    Computer Engineering. 2008, 34(9): 254-256. https://doi.org/10.3969/j.issn.1000-3428.2008.09.092
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    Multi-Input Multi-Output(MIMO) is one of the most potential key technology applying to future wireless communication system. Characteristic of MIMO system is introduced in the paper. MIMO 2x2 system is implemented based on TMS320C6701 EVM. The whole system simulink on matlab is demonstrated and evaluated, and DSP system’s performance is tested.
  • WANG Zheng-fang; NAN Lin; WANG Zuo-peng; SUN Zhao-hua
    Computer Engineering. 2008, 34(9): 257-259. https://doi.org/10.3969/j.issn.1000-3428.2008.09.093
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    This paper proposes J2EE-based Business Information Approval Model(BIAM) to solve shortcomings of approval distributing and data structure in Enterprise Information System(EIS), and introduces the architecture, flow and technique characteristic of this model. A reasonable Data Structure(DS) of business approval is described, and BIAM components is expatiated, including approver, approval programming, approval distributing and so on. BIAM is applied successfully and it can achieve the complicated process of distributing and approving of business information. Approval DS may not be considered in the business information.
  • XU Gang; GENG Ru-bo; LU Ting-jin
    Computer Engineering. 2008, 34(9): 260-262. https://doi.org/10.3969/j.issn.1000-3428.2008.09.094
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    By introducing texture feature analysis technology into polygon mesh modeling, an algorithm to implement surface subdivision based on texture feature value is put forward to model multi-resolution 3D buildings. The algorithm provides a method of triangle splitting depending on the intersection of the triangle sides and the texture feature curves to build self-adaptive subdivided triangle mesh. Through designing the data structure of binary-tree about the self-adaptive subdivided triangle mesh and developing test program, the test indicates that the algorithm has the traits of creating model fast and maintaining better geometric feature and can meet the requirements of large scale modeling and real-time rendering of 3D buildings on PC.
  • YUE Jian-wei; LIN Ai-hua; MEI Tu-shu; PENG Guang-xiong; XI Bin
    Computer Engineering. 2008, 34(9): 263-264. https://doi.org/10.3969/j.issn.1000-3428.2008.09.095
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    This paper uses the method of HIS color transformation and remote sensing image data to gain mining change regions. It overlays changed region on land using data and mining register data, finds and removes the disturbing regions by using GIS analysis functions. The system can attain the illegal information automatically. This method takes full advantage of image data and vector data to avoid employing supervised classification when using the image data only, which is manual and fussy. The method can be used to extract the illegal information rapidly, at low cost and is useful for stopping lawless exploit minerals in time. The method can be mastered easily even the man has no professional technology.
  • ZHANG Tuan-qing; ZHANG Kai-long; LIANG Ke; ZHOU Xing-she;
    Computer Engineering. 2008, 34(9): 265-267. https://doi.org/10.3969/j.issn.1000-3428.2008.09.096
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    This paper optimizes and extends the NTP file format without distortion, and researches into distortion-free algorithm of pattern customization under the condition of fixed stitch length combining with traditional NTP pattern customization algorithm and file format NTPS. The design and implementation of the algorithm are given. It has been proved that this algorithm can solve the distortion problem in pattern customization better than traditional algorithm. The algorithm has triumphantly been used in the pattern-design software “LanHuaHua V1.0” for embedded system of electro-pattern-sewing machine.
  • ZOU Wei-jun
    Computer Engineering. 2008, 34(9): 268-269,. https://doi.org/10.3969/j.issn.1000-3428.2008.09.097
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    This paper divides the software into several thread and schedules the priority according to the scheduling and data-flow of guidance and control system. The real-time multithread software of guidance and control system is implemented on the DSP/BIOS operation system. It is proved that this kind of design method can decrease the complexity of software design, and meet the need of real-time, reliability and efficiency of guidance and control system.
  • HE Yu; LI Jun;
    Computer Engineering. 2008, 34(9): 270-272. https://doi.org/10.3969/j.issn.1000-3428.2008.09.098
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    This paper describes the design and implementation of a Dynamic Load Balancing system(DLB). Based on Linux Virtual Server(LVS), DLB has a comprehensive B/S GUI. DLB can monitor application service and has a 4-layer mechanism of high availability assurance. With special algorithm, DLB can predict future load by analyzing history information to do dynamic load balance, so the throughput and utilization rate of Dawning-4000A cluster are increased.
  • LIANG Jun-xue; YU Bin
    Computer Engineering. 2008, 34(9): 273-275. https://doi.org/10.3969/j.issn.1000-3428.2008.09.099
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    This paper depicts the structure and characteristics of BlueZ based on analyzing the source code of Linux bluetooth stack BlueZ. It analyzes the implementation of bluetooth USB transport driver scheme and data processing procedure in detail, and gives the key data structure and implementation of bluetooth device driver. It summarizes the approach of developing Linux bluetooth USB device driver and the key technology.
  • CHEN Qi; YANG Xiong; FU Zhao-min; QIN Zi-zhen
    Computer Engineering. 2008, 34(9): 276-277,. https://doi.org/10.3969/j.issn.1000-3428.2008.09.100
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    To compare the protein structure, the second-order moment are applied to analyze the protein’s principal component to construct protein three dimension united coordinates. Based on that, the protein’s spatial structure factors are transformed by wavelet to construct protein three dimension spatial structural spectra. Experimental results show that there are some differences in the spectrua of the same group protein under collective similar, and all the differences can be used to explore the hidden eigenvalue of the protein structure, promoting the preciseness of the compare of the protein structure.
  • DAI Ming-xing; DU Yan-hui
    Computer Engineering. 2008, 34(9): 278-280. https://doi.org/10.3969/j.issn.1000-3428.2008.09.101
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    Web spider——WebLech is an open source tool used to download Website. This paper analyzes the characteristics and the workflow of WebLech, improves the initial address settings, and riches the Web’s types which can be achieved by WebLech. It uses the improved WebLech to design a content based search engine which can search in a range of IP address set by customer.
  • CHEN Peng; REN Bo; GUO Zhen-gang; WANG Cheng
    Computer Engineering. 2008, 34(9): 281-282. https://doi.org/10.3969/j.issn.1000-3428.2008.09.102
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    In order to improve the speed of visualization of stratified stratum, the parallel visualization program based on MPI is provided according to the character of the geological exploration data, and the Kriging method is adopted to implement the interpolation computing of the stratums. The computing environment is established using PCs with Windows2000 OS, and the statistic data show that the parallel program can save the computing time efficiently.
  • XU Xin-gang; WU Bing-fang; MENG Ji-hua; LI Qiang-zi
    Computer Engineering. 2008, 34(9): 283-封三. https://doi.org/10.3969/j.issn.1000-3428.2008.09.103
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    The real-time and accurate crop forecasting yield data is an indispensable constituent of agricultural production monitoring information. This paper introduces a crop yield forecasting system which has utilized Oracle DBMS as the database platform, adopted the system framework of Client/Server(C/S), and used Interactive Data Language(IDL) with the character of orienting matrix for the system development. The system integrates multiple models using different types of data together, implements visualization of model analysis, batch process, spatial query of GIS, and so on, and can realize the yield forecasting analysis of dominant food crops at the scale of provincial level to provide the agriculture and food departments with prompt data for decision-making analysis.