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05 January 2010, Volume 36 Issue 1
    

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  • ZHANG Zhong-ping; HAN Li-xia; REN Da-juan; GUO Jing
    Computer Engineering. 2010, 36(1): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2010.01.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to locate a large number of dynamic services with various types in the campus grid effectively, this paper provides a discovery mechanism of campus grid service. According to the Small World theory, this paper establishes Virtual Organization(VO), builds the three-layer architecture model of common node, domain and VO, and proposes IS-Gossip algorithm based on this model. Distributed query is used among the VO on the top layer and the domains of the VO on the middle layer with IS-Gossip algorithm. Centralized query is used in the domain on the bottom layer. Algorithmic analysis demonstrates the mechanism improves the scalability and query efficiency of service discovery.
  • HAN Mu-hua; LIU Lei-bo; WEI Shao-jun
    Computer Engineering. 2010, 36(1): 4-6,14. https://doi.org/10.3969/j.issn.1000-3428.2010.01.002
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    Extracting similar structure and using the structure to cover the system is an effective method for the partition of System-on-Chip(SoC). This paper presents an automatic extraction method of similar structure based on growth, of which Single Template Matching Algorithm(STMA) extracts any kinds of structure of templates, and Multiple Templates Generation Algorithms(MTGAs) uses the incremental and synchronous growth method for all the templates and sub-graphs. Experimental results show that the template containing fan-in and fan-out branches can be supported by the new method, while computing time is reduced by 30%~70% compared with traditional methods.
  • YE Xiao-guo; SUN Li-juan; WANG Ru-chuan
    Computer Engineering. 2010, 36(1): 7-8,11. https://doi.org/10.3969/j.issn.1000-3428.2010.01.003
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    By combining the advantages of Fixed Assignment(FA) protocol, Demand Assignment(DA) protocol and Random Access(RA) protocol, this paper proposes an adaptive hybrid Medium Access Control(MAC) protocol for satellite communication networks, which is named CFDR-MAC. The proportion parameter of assignment boundary can be adjusted flexibly and adaptively, so that MAC protocol can be controlled adaptively. Simulation results show that CFDR-MAC protocol has better throughput, less delay, and it can adapt to various satellite communication networks.
  • ZHANG Fa; ZHAO Qiao-xia
    Computer Engineering. 2010, 36(1): 9-11. https://doi.org/10.3969/j.issn.1000-3428.2010.01.004
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    A traffic simulation platform based on Multi-Agent is designed and implemented. The simulation advances are with fixed-increment, and the scheduler Agent coordinates the activities. The Multi-Agent system is modeled with MaSE method. The interaction between DVE and segment is described with automata. DVE Agent is with S-R hybrid architecture. Road network is hierarchical and it is layered into network, segment (intersection) and lanes. The setting of traffic lights is presented by a tree, whose each leaf is corresponding to a light color for entry lane-traffic. The simulation platform is implemented with Visual C++. It is proved to be able to reproduce the features of traffic flow effectively.
  • LIU Dan; FANG Wei-guo; ZHOU Hong
    Computer Engineering. 2010, 36(1): 12-14. https://doi.org/10.3969/j.issn.1000-3428.2010.01.005
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    This paper proposes Chinese word segmentation model based on Bayesian network, which adopts better smoothing algorithm to achieves word sense disambiguation and automatic recognition of foreign/domestic person names together. Viterbi algorithm is used in the model, which is demonstrated to be more efficient in word segmentation under acceptable accuracy and recall rate. Experimental results show that precision rate is 99.68% and recall rate is 99.7% in close test, with the speed of 74 800 words per second.
  • LIU Zhi-xin; ZHANG Wei; HUA Chang-chun; GUAN Xin-ping
    Computer Engineering. 2010, 36(1): 15-17,2. https://doi.org/10.3969/j.issn.1000-3428.2010.01.006
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    Wireless Medium Access Control(MAC) protocol usually uses distributed contention resolution mechanisms for sharing the wireless channel. This paper presents modifications to the Distributed Coordination Function(DCF) mechanism of IEEE 802.11 protocol, and it proposes an improved algorithm to implement the detection of misbehavior. The penalty measures are taken further to correct the misbehavior. Simulation results show that the ratio of correctly detecting the misbehavior is improved and the throughput of the whole networks is increased with the proposed mechanism.
  • ZHANG Hua-jun; ZHAO Jin
    Computer Engineering. 2010, 36(1): 18-20,2. https://doi.org/10.3969/j.issn.1000-3428.2010.01.007
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    This paper proposes a self-learning algorithms of neural networks based on Genetic Algorithms(GA) and neural network prediction. It uses GA to search the optimum resolution globally. The data generated during the evolutionary process is used to train the predictive networks. When the self-learning of networks converges on the adjacent domains of optimum resolution, it uses the prediction network to predict the map between network parameters and system response. The neural networks’ optimum resolution approximate property guides the GA to converge on the optimum resolution and solve the local oscillation problem of GA. Experimental result proves the fast convergence property of the proposed algorithm through design speed controller of asynchronous machine drive system
  • NAN Guo-fang; LU Xiao-ying
    Computer Engineering. 2010, 36(1): 21-24. https://doi.org/10.3969/j.issn.1000-3428.2010.01.008
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    Wireless Sensor Networks(WSNs) is regard as a distributed database system, in which the sensor nodes sense and store data. Aiming at query multi-queries processing problems, this paper presents a new Multi-Queries Framework(MQF) system with the primary purpose of energy-saving, under the framework, and discusses multi-queries classification algorithm and multi-queries aggregation algorithm. Experimental results show that the algorithms can effectively save the energy consumption and prolong the network lifetime on the same query conditions.
  • WANG Li-min; GAO Xue-dong; MA Hong-quan
    Computer Engineering. 2010, 36(1): 25-26,2. https://doi.org/10.3969/j.issn.1000-3428.2010.01.009
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    This paper presents an algorithm for detecting local community structure based on maximal closeness degree of vertex for resolving the time complexity problems of finding local community structure in complex networks. The algorithm runs in time O(kd) for general graphs. In order to determine the precision and speed of the method, it is compared with the classical local community identification approaches, namely Clauset algorithm. Experimental results shows that the algorithm is as effective as Clauset algorithm on the whole, and the algorithm is much faster than Clauset algorithm.
  • WANG Yu; ZHAO Yue-long; HOU Fang
    Computer Engineering. 2010, 36(1): 27-29. https://doi.org/10.3969/j.issn.1000-3428.2010.01.010
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    Replica strategy is an effective way to improve the scalability, fault-tolerance, and availability in P2P storage system. With the development of new applications, the P2P replica applications change from read-only static files sharing to read-write dynamic files interacting. This paper presents an replica consistency maintenance strategy, an Replica Information Broadcast tree(RBT). The strategy stores the replica information in the binary tree, which makes use of subscribe and unsubscribe algorithm to maintain replica consistency. Experiment proves it can effectively reduce maintenance costs and avoid some associated problems.
  • Software Technology and Database
  • WEN Jun-hao; QIN Jia; ZHAO Rui-feng
    Computer Engineering. 2010, 36(1): 30-32. https://doi.org/10.3969/j.issn.1000-3428.2010.01.011
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    In order to optimize the process execution and reduce the actual cost for operation, optimization of workflow is analyzed in the form of Weighted Direct Acyclic Graph(WDAG). By mapping the nodes, arcs, weights of the WDAG to the events, operations, cost of workflow model correspondingly, this paper constructs a workflow model based on WDAG. It proposes an optimization algorithm that involved two strategies, consolidation optimization and parallel optimization to aim at the sequence process which happens most frequently in workflow. Simulation experimental result proves the validity of the algorithm.
  • WANG Yan; PAN Yu-chun; YAN Bo-jie;
    Computer Engineering. 2010, 36(1): 33-34,3. https://doi.org/10.3969/j.issn.1000-3428.2010.01.012
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    In order to improve the spatial data mining efficiency and accuracy, the research on spatial outlier detection algorithm based on Voronoi and spatial autocorrelation is proposed after analyzing the advantages and disadvantages of the classical outlier detection algorithms. The algorithm calculates local Moran index of non-spatial attribute as the outlier factor by Voronoi neighborhoods without parameter. Experimental results show that the proposed algorithm can outperform other existing algorithms in detection accuracy, user dependency and efficiency.
  • MENG Hui; WANG Li-qiang; HONG Wen-xue
    Computer Engineering. 2010, 36(1): 35-37. https://doi.org/10.3969/j.issn.1000-3428.2010.01.013
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    According to the requirements of visual analysis of high dimensional data, this paper proposes a radius coordinate visualization method that can analyze high dimensional data in the reduced space by maximum likelihood estimation of intrinsic dimension so as to apply a few attributes in radius coordinate visualization. The radius coordinate visualization can reveal interesting relations between classes and features, integrate various machine learning methods to classify dataset in optimal projection that obtained from different variable arrangement. Experimental results applied on the six datasets in UCI database show good performance of accuracy and visualization.
  • GUO Shao-zhong; ZHEN Tao; JIA Qi
    Computer Engineering. 2010, 36(1): 40-42. https://doi.org/10.3969/j.issn.1000-3428.2010.01.015
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    It is short of the functions to analysis and mining great capacity mail data on existing mail data engine. Aiming at this problem, this paper describes and optimizes an efficient great capacity mail data mining algorithm based on directly storage procedure of Relational Database Management System(RDBMS) on performance on many levels after the character of text mining characteristic is studied. Experimental results demonstrate that this algorithm is effective, stable and adaptable.
  • WU Zhi-en; HU Jin-song
    Computer Engineering. 2010, 36(1): 43-44,4. https://doi.org/10.3969/j.issn.1000-3428.2010.01.016
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    According to the situation of Windows Mobile system which does not support normal hook functions and can not be used to protect the registry of system, this paper proposes to build hook functions for the system APIs. Based on the API call process in Windows Mobile system, it builds hook function for the API which regarding to the operation of registry, and intercepts this API. Experimental results shows that it can protect the registry effectively by intercepting the relevant API and improve the system’s security.
  • GUO Jing-jing; GAO Jian-hua
    Computer Engineering. 2010, 36(1): 45-48. https://doi.org/10.3969/j.issn.1000-3428.2010.01.017
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    This paper proposes a minimal test suite generation method. It presents a new method for test suite reduction that attempts to use addition coverage information of test cases to selectively keep some additional test cases in the reduced suites that are redundant with respect to the test criteria used for test suite minimization. It implements the method by modifying an existing heuristic for test suite minimization. Comparing with the existing methods, it can improve the fault detection capability of reduced test suites without severely affecting the extent of suite reduction.
  • ZHANG Ying-chun; ZHANG Dan-feng; YAN De-qin
    Computer Engineering. 2010, 36(1): 49-50,7. https://doi.org/10.3969/j.issn.1000-3428.2010.01.018
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    A rough set model is established to supervise the absolute attribute reduction for information table on the basis of studying the separating capacity. And a novel conception is proposed, which is called discernibility quality based on decision, on the basis of exploring the relations between the ability of discernibility and classifying, and it is an important criterion to supervise the relative attribute reduction for decision table. Several related conclusions are drawn by theoretical analyses in studying discernibility quality, approximate quality and discernibility quality based on decision. Comparison experiment shows that discernibility quality based on decision is finer than approximate quality for describing the ability of classifying.
  • JIN Wei-zu; LI Ping-xin
    Computer Engineering. 2010, 36(1): 51-54. https://doi.org/10.3969/j.issn.1000-3428.2010.01.019
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    Single Sign-On(SSO) can avoid the repetitive authentication processes during accesses to multiple application systems. However, implementing SSO will gather the burden of processing authentication as well as take the risk of single location invalidation even the whole service may be interrupted. Aiming at above problems, this paper proposes an SSO system with clusetering function. It delivers users sign requests to different SSO servers, reduces its loads, and increases reliabilities of the system.
  • ZHU Qing; WANG Xiao-ping; XUE Xiao-ping; SI Wen-ting
    Computer Engineering. 2010, 36(1): 55-57,6. https://doi.org/10.3969/j.issn.1000-3428.2010.01.020
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    A dynamic evolution model of the internetware system based on component is proposed in order to meet the need that internetware system is able to evolve during the runtime. The model takes component as elementary unit and bases on software architecture to deploy and implement the evolution. It takes evolutionary algorithms of component adding, deleting and replacing into account, and introduces consistency checking mechanism to guarantee safety and reliability of the evolution. The model is easy to implement and has universal applicability, so that software systems is able to adapt to the evolution model without a great deal of modification.
  • HAN Lei; PAN Xiao-wen; FENG Lin
    Computer Engineering. 2010, 36(1): 58-60. https://doi.org/10.3969/j.issn.1000-3428.2010.01.021
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    This paper presents an index method for high-dimensional time series databases based on symbol graph. It symbolizes the high- dimensional data sequence into high-dimensional symbol sequence based on labanotation as a pre-process. The database is indexed by using symbol state transformation graph. Experiments on Motion Capture Database provided by CMU Graphics Lab show the effectiveness of this method.
  • MENG Fan-xin; ZHANG Jing-jun; LIU Guang-yuan
    Computer Engineering. 2010, 36(1): 61-63. https://doi.org/10.3969/j.issn.1000-3428.2010.01.022
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    Aspect-Oriented Programming(AOP) is introduced to Web services, whose crosscutting concerns such as logging, transaction, authorization, etc. They are separated and realized individually as aspectual services. When the system runs, a weaver weaves them at SOAP message level to construct the final system. Combining Service-Oriented Architecture(SOA) and J2EE multi-tier architecture, a multi-tier system architecture based on aspectual services and Web services is proposed. And a case is designed according to the system architecture.
  • WANG Hai-tao; LIU Shu-fen
    Computer Engineering. 2010, 36(1): 64-66. https://doi.org/10.3969/j.issn.1000-3428.2010.01.023
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    For the common user, implementing the process of parallel competing on the specialized cluster, there are several questions, such as high expense, difficult management, complex operation and so on. To solve these problems, this paper uses the lab condition of connection between PC and Ethernet, adopts the key technologies of the cluster and parallel computation, and proposes parallel computing system circumstance based on the Linux cluster. The test to the system performance is carried on, and the system availability is proved.
  • ZHENG Yue-feng; YUE Li-hua
    Computer Engineering. 2010, 36(1): 67-69. https://doi.org/10.3969/j.issn.1000-3428.2010.01.024
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Building an aspect weaver into Database Management Software(DBMS) is a key difficulty of research on Aspect-Oriented Database(AODB) systems. Based on current research results that raise weave-on-demand and weave history mechanisms, this paper gives a weaving approach implementation based on Log. This approach not only gives the concrete implementation of weave-on-demand, reweave and weaving history, but also gives individual mechanisms for fast recovery of aspect weave state when system restart normally or abnormally. This approach is a good complement and perfection for research on building an aspect weaver into DBMS.
  • LIU Chao; YANG Jin-min; ZHANG Da-fang
    Computer Engineering. 2010, 36(1): 70-72. https://doi.org/10.3969/j.issn.1000-3428.2010.01.025
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    Current Web Services fault-tolerant technologies cost too much resource due to their static configuration characteristics, and are inconsistent with the idiosyncrasy of Web Services systems. This paper proposes a fault-tolerant method employing service replacement strategy, which counts on the specialty of Web Services systems. The main idea of the strategy is replacing the invalid service with the equivalent service on Internet. The feasibility of this strategy is proved by experiment.
  • CAI Hong; SHEN Lei; LI Yong-hong
    Computer Engineering. 2010, 36(1): 73-75. https://doi.org/10.3969/j.issn.1000-3428.2010.01.026
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    This paper gives a solution of a general way for automatic tailoring while transplanting a software to an embedded system. The solution is based on the technique of coverage test. It makes static analysis for the source code which is tailored, and inserts the stub code into the beginning and ending of each function. After instrumentation, it executes the code and gets the coverage information. It tailors those functions which are never used. Though this way, it can reduce the size of software by about 30%.
  • WU Xiao-yong; LIU Lei; ZHU Yi-fan; JING Tao
    Computer Engineering. 2010, 36(1): 76-78,8. https://doi.org/10.3969/j.issn.1000-3428.2010.01.027
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    By analyzing the basic characteristics of use of Data Warehouse of Armament System of Systems(DWASS), this paper gives a new framework and marts of DWASS. It puts forward a new three-dimensions Data Structure(3D-DS), which includes the dimension of basic data, the dimension of metadata and the dimension of model, and the relationships among 3D-DS are revealed. It formalizes the 3D-DS. A new way called “ladder method” is proposed to manage metadata in DW. An example is introduced to explain the function of 3D-DS works in DW environment.
  • ZHONG Qi-gen; WANG Xi-wu; HUANG Xiao-cheng
    Computer Engineering. 2010, 36(1): 79-81. https://doi.org/10.3969/j.issn.1000-3428.2010.01.028
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The conception of database interaction complexity metrics is introduced based on the principle and methodology of software metrics. A vector composed of four indexes is used to represent the interaction between program and DBMS. Another vector of corresponding weight values is defined according to the need of the test of Database Application(DA). By multiplying the two vectors, the unitary complexity metrics value is calculated. Experiments show that the metric method is impersonal, accurate and flexible in measuring the interaction of DA.
  • GAO Feng; WAN Xiao-dong
    Computer Engineering. 2010, 36(1): 82-84. https://doi.org/10.3969/j.issn.1000-3428.2010.01.029
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    On the premise of guaranteeing the users’s Quality of Service(QoS) requirements and to research the method how to promote the grid system performance, a global utility heuristic schedule strategy for grid meta-task is proposed. The immediate schedule arithmetic MGU and batch schedule arithmetic Global USufferage are designed. Simulation experimental results show this strategy can get higher user satisfaction, and meanwhile ensure the system throughput and stability.
  • YU Hong; WAN Chang-xuan
    Computer Engineering. 2010, 36(1): 85-86,9. https://doi.org/10.3969/j.issn.1000-3428.2010.01.030
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    According to feature of semi-structure of XML documents, a new effective method for modeling documents of XML retrieval result segment is brought forward, and a method for computing relativity of keywords and measuring similarity of structure semantics between documents is designed. A new algorithm named Dynamic k-means Soft Clustering(DKMSC) is brought forward to meet requirement of clustering retrieval results. Experiment indicates that the method of clustering XML retrieval results is obviously better than the traditional way.
  • Networks and Communications
  • WANG Jian-sheng; CAO Ye-wen
    Computer Engineering. 2010, 36(1): 87-90. https://doi.org/10.3969/j.issn.1000-3428.2010.01.031
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    According to the principle of mobile multicast algorithm for dynamic multicast Agent, this paper proposes a mobile multicast protocol. It adopts a novel fast multicast swithc mechanism and selects the multicast Agent dynamicly according to the time measurement and distance measurement. Simulation results show that this protocol avoids the frequent reconstruction of multicast delivery tree, decreases the multicast switch delay. It has the near-optimal multicast transfers path and capability of integration with the existing network protocols.
  • YU Rui-yun; WANG Xing-wei
    Computer Engineering. 2010, 36(1): 91-93,9. https://doi.org/10.3969/j.issn.1000-3428.2010.01.032
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    Mobile Element(ME) are usually exploited for collecting and relaying data in sparse wireless sensor networks. This paper proposes the Voronoi Diagram-based Mobile Element Schedule(VDMES) algorithm to construct the shortest possible path for ME data collection. ME are scheduled to visit a small subset of Voronoi vertices, which exactly covers all sensor nodes in a given transmission radius. Simulation experimental result shows that the path concatenating the Voronoi vertices is much shorter than that formed by regular sensor nodes.
  • ZHANG Peng; ZHAO Ji-hong; QU Hua
    Computer Engineering. 2010, 36(1): 94-96. https://doi.org/10.3969/j.issn.1000-3428.2010.01.033
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    Aiming at the deficiency of the existing local repair technology, this paper proposes a new local repair scheme based on link failure. It is on the basis of AODV local repair and concerns about status of nodes. Link failures are classified and different methods are adopted for different link failures. Simulation result indicates that the improved technology can promote network performance by reducing route setup time and control packets.
  • DUAN Zhao-lei; GU Zhi-min
    Computer Engineering. 2010, 36(1): 97-98,1. https://doi.org/10.3969/j.issn.1000-3428.2010.01.034
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    Since the feature of resource requirement in Web proxy cluster is dynamic and resource requirement information is also hard to obtain, existing dynamic load balancing strategies are difficult to be applied in Web proxy cluster. A new self-adaptive load balancing strategy for Web proxy cluster is presented. The load model of proposed strategy can adapt itself to variation of task resource requirement feature dynamically. Therefore load status of system and load difference among nodes can be reflected more precisely. Experimental results show that the average response time of the presented strategy is about 15% to 20% lower than that of other load balancing strategies.
  • LAN Hai-yan; YANG Shen-yuan; TAN Feng; MA Xue-song
    Computer Engineering. 2010, 36(1): 99-101. https://doi.org/10.3969/j.issn.1000-3428.2010.01.035
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    Two-scattering elliptical Multiple Input and Multiple Output(MIMO) channel model is established for micro-cell. The channel correlation characteristic between sending and receiving element antenna is analyzed. On considering the existence of a lot of scattering bodies, which is of non-uniform distribution, around the transmitter and receiver, the closed expression type of channel correlation function is obtained describing the distribution of scattering angle by Von Mises distribution function. The main factors affecting channel correlation characteristic is analyzed. Experimental results show the correlation coefficients reduces non-monotoniclly with the increase of antenna distance, angle expansion and expansion factor, which provides efficient theoretical base for the application of MIMO system.
  • HONG Li; WANG Guo-qiang; XU Shun-jie; ZHOU Zheng
    Computer Engineering. 2010, 36(1): 102-103,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.036
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    To solve the problem on unnecessary energy-consumption caused by redundant links in Directed Diffusion(DD) algorithm during data propa- gation and reinforcement between multiple sources and sink node in Wireless Sensor Network(WSN), a new routing algorithm, Directed Diffusion based on Cluster of Sources(DD-CS) is presented. All the sources of network are in a same cluster, and redundant links are reduced when sink node only communicates with the cluster head chosen by centripetal degree of node. Theoretical analysis and simulation show that DD-CS is effective and energy consumption is lower than that of directed diffusion, the improved efficiency is related to the network scale and running time.
  • LI Yang-hui; ZENG Zhi-wen; CHEN Zhi-gang; ZHAO Ming
    Computer Engineering. 2010, 36(1): 104-106,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.037
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    On basis of the series of subsection monitoring thought, this paper proposes an approach which uses cumulative trust to measure intermittent failure in Mobile Ad hoc NETwork(MANET). In the one-time monitoring, the information entropy is used for taking down the intermittent of nodes response, and a new distributed monitoring scheme with several collaborative detection methods based on pseudo-space distance are defined in this paper. This approach is much better than the old. In order to improve on the veracity of detection when nodes with high mobility, by the series of subsection monitoring, the monitoring results are seen as classifiers, and the intermittent failure is measured by the cumulative trust. Simulation experimental results show this approach is effective and feasible.
  • WEI Shu-jie; BAI Guang-wei; SHEN Hang; JIN Yong
    Computer Engineering. 2010, 36(1): 107-109. https://doi.org/10.3969/j.issn.1000-3428.2010.01.038
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    An adaptive congestion control mechanism called TCP_Acc for wireless Mobile Ad hoc NETwork(MANET) is proposed. For a given statistical bandwidth at the data link layer, this mechanism uses a GM(1,1) model to predict the network conditions in the future, and adjusts the congestion window adaptively, according to the predicted bandwidth. Simulations experimental results demonstrate this mechanism can improve significantly and effectively the TCP reliability and QoS of real-time communication over wireless MANET, in terms of lower packet loss rate, end-to-end delay, and so on.
  • ZHOU Ping; ZHANG Sheng; SHU Jian
    Computer Engineering. 2010, 36(1): 110-111,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.039
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    Through the analysis of the node energy attenuation, this paper uses energy attenuation forecast model to describe the law of energy consumption. The reporting mechanism based on the forecast model is set up, which can significantly reduce the reporting counts, data traffics in netsworks and node consumption. Experimental results show the working time of Telosb node can expend 1%~4.5% after using this forecast model.
  • LIU Lei; JIANG Hong
    Computer Engineering. 2010, 36(1): 112-114. https://doi.org/10.3969/j.issn.1000-3428.2010.01.040
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    Wireless Ad Hoc network is a kind of distributed self-organizing network with no infrastructure or central control. Aiming at Ad Hoc network, this paper proposes a Multi-Strategy Data Transmission Scheme(MSDTS) based on chain formation, alternate node and ferry transmission to explore the unknown environment and capture the relevant data. This scheme is simulated by network simulation tool named NS2, and the results show that MSDTS has good performance in the building of chain Ad Hoc network, data drop rate, average throughput of networks.
  • LI Yu-yan; ZHAO Rong-cai; JIN Xiao-yan; XIAO Jin-ge
    Computer Engineering. 2010, 36(1): 115-117. https://doi.org/10.3969/j.issn.1000-3428.2010.01.041
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    在给定协议的网络环境下,不同网络流量对QoS造成的影响不同,具有LRT特征的网络流量给网络QoS带来的影响较大。分析吞吐量和响应时间与LRT流量之间的关系。利用基于多核技术的网络处理器产生精确LRT流量并对其进行测试,结果表明与平缓流量相比,LRT流量对网络QoS的影响更大。
  • YUE Hai-bing; GE Hong-wei
    Computer Engineering. 2010, 36(1): 118-120. https://doi.org/10.3969/j.issn.1000-3428.2010.01.042
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    Aiming at the energy heterogeneous wireless sensor network, this paper proposes a clustering algorithm. This algorithm adopts cluster head competition parameter based on the condition of node’s resident energy distributing. It decreases energy consumption for communication in the process of clustering and realizes unifrom distribution of cluster head. Resident energy of cluster head and the energy consumption of its base station are considered synthetically between clusters to select the appropriate next-hop route node. Simulation results show that the algorithm can balance the network energy consumption, improve the utilization efficiency of node energy and prolong the network lifetime.
  • LI Bo-guang; JIN Shun-fu; ZHANG Zhe-rui; HAN Li; LI Ran-ran
    Computer Engineering. 2010, 36(1): 121-123. https://doi.org/10.3969/j.issn.1000-3428.2010.01.043
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    According to the operation mechanism of the sleep mode for the power saving type I in IEEE 802.16e, this paper builds a multiple vacation queueing model with exponential variational vacation length. The queueing parameters such as queueing length with steady state, the average waiting time and the average busy cycle are given. The formula of the energy saving ratio and the performance measure of average response time are derived. Dependency relationship between the system performance measures and the size of initial sleep window are obtained through numerical examples.
  • WU Wen-jia; ZHANG Jian-zhong; ZHANG Yuan-peng
    Computer Engineering. 2010, 36(1): 124-126. https://doi.org/10.3969/j.issn.1000-3428.2010.01.044
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    By analyzing the existing network topology inference algorithms, this paper presents an improved multicast network topology inference algorithm based on packet loss rate. It combines the hop count of receivers, the Hamming distance and the number of received probes and can infer multicast network topology and loss performance simultaneously. It adapts dynamically the value of threshold according to the estimation of link packet loss rates, it improves the accuracy of the inference. Simulation results show that compared with the existing algorithms, this algorithm has better performance.
  • SONG Qi-chang; HU Jun; WANG Dong
    Computer Engineering. 2010, 36(1): 127-130. https://doi.org/10.3969/j.issn.1000-3428.2010.01.045
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    Considering the shortcomings of the P2P streaming media technology, which based on the model of the tree topology and extensions and Gossip protocol in media data distribution, the model of P2P streaming media live system based on regionalization is proposed, and a dynamic self-governing regionalization mechanism is used. In a large-scale live streaming media network system, the new model reduces the probability of network congestion, and optimizes bandwidth and latency of the system, while improving the streaming data resource utilization.
  • DENG Li-lin; ZHANG Cui-fang; ZHOU Xing-jian; SHI Yun-zhong
    Computer Engineering. 2010, 36(1): 131-133. https://doi.org/10.3969/j.issn.1000-3428.2010.01.046
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problem that conventional spectrum sensing technique is usually focused on signal band, this paper introduces a multi-band joint detection spectrum sensing scheme for Orthogonal Frequency Division Multiplexing(OFDM) system, which jointly detects a bank of multiple narrow-bands based on the energy detection in order to maximize the aggregate opportunistic throughput in an interference limited cognitive radio network. Simulation results show that the performance of multi-band joint detection scheme is improved compared with the conventional sensing method which uses the same threshold over multiple frequency bands.
  • ZHANG Hai-yang; ZENG Fan-zi; LUO Juan; LI Ren-fa
    Computer Engineering. 2010, 36(1): 134-135,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.047
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Most current protocols just achieve the local energy balance of Wireless Sensor Networks(WSNs). To solve this problem, a modified energy balance routing algorithm is proposed. It constructs a layered network by minimum hop count, and uses a mixed transmission mode resulting from hop-by-hop forwarding combined with direct forwarding. In hop-by-hop transmission, it uses the modified multi-path routing scheme based on maximum energy path. Simulation results show the lifetime of the networks is prolonged efficiently.
  • Security Technology
  • ZHONG Wei; SHU Jian; YANG Feng-yu; LIU Lin-lan
    Computer Engineering. 2010, 36(1): 136-138. https://doi.org/10.3969/j.issn.1000-3428.2010.01.048
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The delegation technology can solve the authorization problem of users in distributed environment, which makes the permission management flexible. However, it is possible to cause the issues of cycle authorization and permission diffusion in the process of multi-step delegation. On the basis of T-RBAC, the paper proposes a DR-TRBAC model based on delegation depth and role range. It creates delegation tree according to delegation relationship of one task. The cycle authorization problem is solved by limiting delegation depth. The permission diffusion is controlled by setting the maximum of role range between users. The feasibility of DR-TRBAC is proved through an application.
  • HUANG Meng-qiao; LI Qing-guo; MA Chang-she
    Computer Engineering. 2010, 36(1): 139-142. https://doi.org/10.3969/j.issn.1000-3428.2010.01.049
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In traditional signcryption scheme, signature can only be verified by the recipient, which implicates that signcryption can not be used to construct fair exchange protocols directly. Aiming at such problem, this paper presents a verifiable signcryption scheme and its security model. Based on bilinear pairs, an efficient verifiable signcryption algorithm is proposed. And the unforgeablity and security of the scheme in the random oracle model is proved.
  • FAN Ming-hu; FAN Hong; WU Xiao-jin
    Computer Engineering. 2010, 36(1): 143-145. https://doi.org/10.3969/j.issn.1000-3428.2010.01.050
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    Privilege management subsystems are difficult to be reused in different application systems because of the differences in resources and complexity of privilege management. This paper designs a universal privilege management system that can be reused in small-and-medium-sized Web application system by expanding Role-Based Access Control(RBAC) partly implemented in ASP.net and complementing resources management. Its key technologies are expatiated with some examples from the granularity of access control, and it is proved that the system can simplify the design and implementation of privilege management and reduce the workload of Web application system development.
  • HUO Jian-lei; FAN Xun-li; FANG Ding-yi
    Computer Engineering. 2010, 36(1): 146-148. https://doi.org/10.3969/j.issn.1000-3428.2010.01.051
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problem that it will cause extra costs when introducing control flow obfuscation and data obfuscation, this paper presents four renaming algorithms including overusing identifiers algorithm, overloading unrelated method algorithm, introducing illegal identifiers algorithm and overriding static methods algorithm. An obfuscator named JIRO(Java Identifier Renaming Obfuscator) is constructed based on the algorithms, and its performance is analyzed. The results show that JIRO achieves good obfuscation effects without extra implementation costs of the bytecode.
  • ZHENG Hui; XU Ci-wen
    Computer Engineering. 2010, 36(1): 149-150,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.052
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    Without lowering the security, this paper improves an one-way trapdoor permutation in a public-key encryption scheme, and proves the security of the new scheme. It improves a digital signature which is the application of this one-way trapdoor permutation, and analyses its security and efficiency. Result shows that the efficiency of encryption and decryption of the new scheme is markedly improved.
  • YOU Wei; CHEN Shao-zhen
    Computer Engineering. 2010, 36(1): 151-153. https://doi.org/10.3969/j.issn.1000-3428.2010.01.053
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    The vehicular networks for safety messaging have particular requirements on the applicable cryptographic primitives. It requires that cryptographic overhead is low and many messages from many different signers are verified very quickly, and moreover that is privacy-friendly. This paper adopts the small exponents test, takes advantage of the peculiarities of bilinear maps, and proposes an efficient batch verifier for a short group signature scheme to satisfy all three above requirements, with a verification time where the dominant operation requires only two pairings.
  • SHI Guo-dong; KANG Fei; GU Hai-wen
    Computer Engineering. 2010, 36(1): 154-156,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.054
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper introduces the background and feasibility of building the unified description model for block cipher. Studying on structure of many block ciphers and inducing the function of every part of it, it concludes many universal components of block ciphers. It presents the unified description model for block cipher in the form of relationship between components and the flow of block cipher, and supplies the definition and function instruction of all components, and applies the model on the camellia.
  • YANG Cheng-yun; ZHANG Ming-qing; TANG Jun
    Computer Engineering. 2010, 36(1): 157-160. https://doi.org/10.3969/j.issn.1000-3428.2010.01.055
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Mobile Ad hoc networks usually use Ad hoc On-demand Distance Vector(AODV) protocol for lower overhead, but vulnerable to attacks for the lack of security mechanism. A security enhancement scheme based on Elliptic Curve Cryptography(ECC), self-certified pubic key, one-way Hash-chain is proposed, it establishes the session key between source and destination. Experimental results show that the proposed protocol is secure and efficient.
  • ZHANG Zhi-jun; GUO Yuan-bo; LIU Wei; LV Jin-na
    Computer Engineering. 2010, 36(1): 161-163,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.056
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper proposes a group key agreement protocol based on m-tree and DH protocol to improve the poor scalability and efficiency of most group key agreement protocols in dynamic peer communication. Compared with TGDH, this protocol reduces the depth of key tree efficiently and computing costs of group key agreement by adopting m-tree. Compared with GDH, this protocol reduces communication costs of the group key agreement through layer-by-layer agreement. Communication and computing costs are balanced by variable m-tree, which makes a great progress in applications of LAN and WAN.
  • ZHAO Feng; FENG Jin-lei
    Computer Engineering. 2010, 36(1): 164-165,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.057
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper gives some polynomial lemmas and proof of lemma. On basis of these lemmas, the expression of Linear Complexity(LC) of periodic sequences is gave. Application of the expression show the most important result of this article, a relationship between m(s) and the LC of a given sequence s with period N=2pn over GF(2). Where p is an odd prime, 2 is a primitive root module p. Combined with Wei algorithm, it gives two examples to prove the results. Result shows that the relationship is correct.
  • HUANG Xue-yu; WEI Na; TAO Jian-feng
    Computer Engineering. 2010, 36(1): 166-169. https://doi.org/10.3969/j.issn.1000-3428.2010.01.058
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A novel abnormal detection algorithm based on artificial immune clustering is presented. The outlier measure of selection abnormal item from dataset based on distance is employed in this algorithm, which makes it easy to get better tradeoff between detection rate and false positive rate according to security policies chosen by user. Experimental results show that because this algorithm can label the abnormal activities without training dataset, it can be applied in different network system and application environments.
  • ZHANG Xiao-bin; HAN Ji-hong; WANG Ya-di; LIU Min
    Computer Engineering. 2010, 36(1): 170-173,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.059
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the nodes’ public key certificates, this paper proposes a clustering-based session key agreement protocol in Ad Hoc networks using the Elliptic Curve Cryptography(ECC). It analyzes the security and efficiency of the protocol. The protocol satisfies the common admissive security demands in key agreement. It can resist the man-in-the-middle attack, replay attack, message forge attack and so on, the requirement of computation and storage in mobile terminal is reduced, and the communication burden in the process is lessened effectively.
  • ZHANG Jing-an; GUO Xian-e
    Computer Engineering. 2010, 36(1): 174-176,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.060
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To resolve the risk problem of transaction in P2P network, by simulating interpersonal interactive process in society network, a trust management model based on dynamic recommendation is proposed. Based on fuzzy cluster algorithms and the interactive context, recommendation nodes are selected dynamically. According to results of cluster analysis, recommendation factors are computed and the reliability of recommendation is enhanced. Analysis and simulation experiments show that the method can improve the accuracy of recommendation effectively and strengthen the availability of P2P network.
  • BU Fan
    Computer Engineering. 2010, 36(1): 177-180. https://doi.org/10.3969/j.issn.1000-3428.2010.01.061
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper analyzes the method of algebraic attacks based on Minisat. It finds that the functions which are built from this method are redundant for some ciphers, gives a pretreatment method to throw off these redundancy functions and a method of algebraic attack based on this pretreatment and using Minisat to solve functions. Using this improved method, experimental results show that the method can cut down half time of one attack on average on CTC algorithm. These redundant functions make the algebraic attack based on Minisat becomes inefficient.
  • ZHANG Xiao-yan; ZHANG Xiao-ming
    Computer Engineering. 2010, 36(1): 181-183. https://doi.org/10.3969/j.issn.1000-3428.2010.01.062
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An information hiding model and its hiding algorithm is proposed along with to meet the need of copyright protection and covert communication of the Flash products. The Flash file is required to read in the form of byte array. The algorithm is desgined in embedding or extraction based on the parity of the number of bit ’1’ in each byte among the byte array. Experimental results show that the approach can not influence the playback effect of the Flash, and it can play the role of encryption. The method has features of high capacity, good security and anti-attack.
  • HUANG Ming; ZENG Qing-kai;
    Computer Engineering. 2010, 36(1): 184-186,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.063
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    Aiming at the problems of selecting classification attributes in software vulnerability classification, this paper presents some concepts about software vulnerability, and discusses the basic principles of selecting the objects and the attributes. By comparing and summarizing five typical taxonomies, a new thought of classifying software vulnerabilities is presented. The problems in current researches are analyzed, and corresponding improvements and developing trends are given.
  • ZHEN Hong-hu; CHEN Yue; LI Le; MA Hui-juan
    Computer Engineering. 2010, 36(1): 187-188,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.064
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the construction scheme of the one-off public key, this paper proposes two attack forgeries, and indicates that their schemes are universal forger. It proposes a new construction of one-off public key, which is based on the super singular elliptic curve and only utilizes common elliptic curve digital signature algorithm. The scheme is robust against the two attack forgeries, with perfect security and high efficiency. As user’s public key is different every time, it can be applied to implementing Internet anonymous attestation for privacy protection.
  • LIU Shang-li; ZHAO Jing-qiang; NIE Qin-wu
    Computer Engineering. 2010, 36(1): 189-190,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.065
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper examines the ability of Advanced Encryption Standard(AES) against the differential fault attack. It uses the byte-oriented fault model against AES key schedule, and compares the differences between correct and faulty secret information embedded in a system to retrieve seed key. Theoretically, the 128 bit master key for AES can be obtained by using 104 faulty ciphertexts and retrieving 2 bytes of tenth round keys by exhaustive search. For the fact that the byte position where the fault happens is not equally distributed, there is little differences between the theoretical value and the number of faulty ciphertexts needed in the attack experiment result.
  • Artificial Intelligence and Recognition Technology
  • ZHANG Jia-cheng; FANG Yong; CHEN Nian-nian
    Computer Engineering. 2010, 36(1): 191-193. https://doi.org/10.3969/j.issn.1000-3428.2010.01.066
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    According to the different degree distortion of CCD lens used in machine visual detection and high precision measurement, this paper proposes a combined model-based for CCD lens distortion correction. The algorithm uses the classical model to correct the distortion image initially, the polyhedral function is employed for second high precision correction, and cubic B spline function is used for grade rebuilding. Experimental results indicate that the algorithm can promote the precision and strengthen the robustness compared with other single lens distortion correction model, and the radial correction RMS is 0.3 pixel.
  • HUA Jie; CUI Du-wu
    Computer Engineering. 2010, 36(1): 194-196. https://doi.org/10.3969/j.issn.1000-3428.2010.01.067
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problems of Genetic Algorithm(GA) which is used to seek the global optimums in multimodal-function-optimization, an Adaptive Niche Genetic Algorithm based on Individual Optimization(IOANGA) is proposed. The IOANGA, which is based on adaptive Niche GA, makes use of the information of the nearest individuals generated in the process of evolution to shrink the search space and improve the ability of local search. Experimental results show that IOANGA is a much more competent optimization method than GA and other Niche methods.
  • LUO San-ding; SUN Xi-mei
    Computer Engineering. 2010, 36(1): 197-200. https://doi.org/10.3969/j.issn.1000-3428.2010.01.068
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at poor accuracy affected by noise and high complexity of calculating in computer vision theoretical framework guiding vision, a new humanoid vision of the closed-loop system model is put forward, a feedback mechanism and the guidance of high-level knowledge is introduced, and they are applied to vehicle license plate location system. Results show that the system not only can accurately locate vehicle license plate and have high fault tolerance, but also can effectively solve location problem under the circumstance of uneven illumination, depigmentation or complex environments interferences.
  • FAN Yan; ZHENG Yu-jie; WU Xiao-jun; YANG Jing-yu
    Computer Engineering. 2010, 36(1): 201-202,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.069
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Linear Discriminant Analysis(LDA) is one of the classical and popular methods used for feature extraction. In this paper, a new algorithm called Symmetrical LDA(SLDA) based on frontal facial symmetry is proposed. This algorithm is based on the theory of function decomposition and mirror symmetry. In the algorithm, mirror transform is introduced. Original face samples are decomposed into even symmetrical images and odd symmetrical ones. Even/odd symmetrical discriminant features are extracted from the corresponding samples respectively. Both theoretical analysis and experimental results demonstrate this algorithm not only enlarges the number of training samples, but also remarkably improves the recognition rates.
  • GU Ji-hai; JIN Xiang-yang;
    Computer Engineering. 2010, 36(1): 203-205. https://doi.org/10.3969/j.issn.1000-3428.2010.01.070
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the deficiency of sensor correlation identification of model algorithm, a new sensor correlation extraction and recognition algorithm is proposed based on Fuzzy ART neural network, of which the diagnosis system is consisted with immune network. By the simulation of temperature sensor fault in certain thermal control system, the method is valid. Simulation result shows that the system can recognize and diagnose the faults accurately, regardless of s single or multiple sensor faults. The accuracy of recognition and diagnosis is above 90 percent when the sensor output is less than ±5 percent deviation.
  • CHEN Xue-yun; ZHANG Zhen-rong; LENG Song
    Computer Engineering. 2010, 36(1): 206-207,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.071
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Integral projection method is a basic method for eye location, but lighting disturbance often makes it invalid. Aiming at such fault, the circle difference operator’s mean value of fluctuation as projection method in stead of the usual gray average method is proposed to enhance its performance against lighting disturbance. The Haar wavelet method is used to filter the noises of the projection curve. And the similarity of two eye region’s vertical projection curve is utilized to localize the eye’s position. Experimental results based on Yale face database show that this new method is simple and efficient.
  • GUAN Chao; JIANG Jian-zhong; GUO Jun-li
    Computer Engineering. 2010, 36(1): 208-210. https://doi.org/10.3969/j.issn.1000-3428.2010.01.072
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A fast algorithm to perform multiple patterns match in a string is described. The proposed match algorithm is based on the concept of Deterministic Finite State Automata(DFSA), combining the advantages of Boyer Moore’s algorithm, the fast algorithms for single pattern matching. In general, it does not need inspect each character of the string. It skips as many characters as possible by making full use of the succeeded match information and failure information during the matching. The proposed algorithm achieves excellent performance in the cases of both short patterns and long patterns. Experimental results show that in the case of short patterns, the time it takes to search a string is 1/2 of the time DFSA method takes, and in the case of long patterns, the time is only 1/3 of the time by DFSA method.
  • XUE Hai-dong; ZHU Qun-xiong
    Computer Engineering. 2010, 36(1): 211-214. https://doi.org/10.3969/j.issn.1000-3428.2010.01.073
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the thoughts of structured analogy forecasting, a novel algorithm is proposed to solve the numeric time series probability prediction problem named Structured Analogy Prediction for Time Series(SAP-TS). SAP-TS constructs the conditional probability distribution through analogies, which avoids the obstacles encountered by classical probability methods, either weak predictability or intractable extremely large contingency tables, which also incurs lack of data problem. Furthermore, SAP-TS offers integrated confidence index to evaluate the prediction accuracy instantaneously. When applying SAP-TS to predict the acetic acid amount of Purified Terephthalic Acid(PTA) solvent system, the prediction results are more precise than the results of Generalized Regression Neural Network(GRNN). The previous best method, and the integrated confidence index also effectively evaluate the prediction accuracy.
  • Graph and Image Processing
  • LUO San-ding; HE Jun-yao
    Computer Engineering. 2010, 36(1): 215-217. https://doi.org/10.3969/j.issn.1000-3428.2010.01.074
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    Aiming at the low precision and slow speed of registration, this paper propose an algorithm for automatic mosaic of image sequence. Using SURF vector is to judge if two images are overlapped and ascertain the relationship of the overlapped images. The detected features are regarded as moving objects, located by the KLT track algorithm, and accurate homography matrix between the two images is obtained. It proposes a color fusion method to achieve seamless splicing based on visual feature. Experimental results show that the precision and speed of registration are improved and the algorithm is robust.
  • QU Xin; TONG Xue-feng; XUAN Guo-rong; TENG Jian-zhong; SHI Yun-qing
    Computer Engineering. 2010, 36(1): 218-220. https://doi.org/10.3969/j.issn.1000-3428.2010.01.075
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper proposes a lossless data hiding technique for JPEG image based on histogram pairs. Hidden data are embedded into the JPEG image quantized DCT coefficients by adjusting the histogram and extracted out without the original image while the original image can be reconstructed without any distortion. It can obtain good performance in high payload and high PSNR with two optimum thresholds and optimum blocks and regions of the JPEG DCT coefficients.
  • HAN Wei-jie; LI Xiao-mei; ZHANG Wen
    Computer Engineering. 2010, 36(1): 221-223,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.076
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to research the parallel image rendering technology deeply, the process of rendering pipeline is introduced, and the inherent possibility of parallelism is analyzed. The various methods for realizing parallel rendering are researched, including pipeline parallelism, data parallelism and task parallelism, as well as sort-first, sort-middle and sort-last. The key problems faced with it are discussed. The development of parallel rendering in the future is discussed.
  • TIAN Xiao-chen; YANG Dong; DU Chun-hua
    Computer Engineering. 2010, 36(1): 224-226,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.077
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    To improve the quality of image retrieval, this paper uses Harris color point extractor to extract Color Points Of Interest(CPOI), and designs annular color histogram. Based on Contourlet transformation of images, texture information of images is extracted by using Contourlet histogram and the rotation invariance is improved. Simulation experimental results show this method can retrieve colorful images fastly and accurately.
  • WANG Wen-yuan
    Computer Engineering. 2010, 36(1): 227-228,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.078
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper presents an algorithm to estimate the Signal Noise Ratio(SNR) for a single image. It defines that the SNR as the ratio of the signal intensity of image and the standard deviation of noise. Based on decorrelation criterion, it can obtain the optimal Gaussian filter, which is used in the accurate estimation of the standard deviation of noise, and it can obtain the robust estimation of the signal intensity of image through the Gaussian filtered image with a large scale. Quantitative experiments demonstrate that the proposed algorithm has high accuracy and validity.
  • LI Fu-cheng; ZHOU Li-li; LI Lei; YAN Bin
    Computer Engineering. 2010, 36(1): 229-230,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.079
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the shortage of the existing despeckling algorithms which can not suppress the noise and preserve the edge at the same time, an adaptive edge-preserving algorithm for Synthetic Aperture Radar(SAR) image despeckling is proposed. Relative deviation, ratio of averges and spatial correlation of pixels are applied to distribute the weight for the filter. Due to the use of the three kinds of local information synthetically, experimental results show that better performances are achieved both in area smoothing and edge preserving.
  • LI Yu-tian; JIN Xiao-li
    Computer Engineering. 2010, 36(1): 231-232,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.080
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The problems in traditional image border tracking are analyzed. According to Freeman chain code boundary tracking method, a pixel-based boundary tracking method of vertex is given. The image pixel vertex matrix is defined. The pixel matrix is used to track the boundary vertex. The boundaries track search rules is set up. The apex of the boundary chain code is abstracted, and the tree structure is generated. The pixel vertex chain code value is used to indicate the boundary. Experimental results show this algorithm is better than the Freeman chain code tracking methods, and has a wider versatility.
  • Engineer Application Technology and Realization
  • ZHAO Fa-gang; CHEN Jin; LI Yi
    Computer Engineering. 2010, 36(1): 233-235. https://doi.org/10.3969/j.issn.1000-3428.2010.01.081
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problems of tight-coupling, poor scalability and flexible for traditional diagnosis system, a model of Service-Oriented Architecture(SOA)-based machinery monitoring, diagnosis and prognosis system is proposed, which solves the problem of resource integration. An open and extendable architecture is put forward, which is based on SOA. A Windows Communication Foundation(WCF)-based enterprise monitoring, diagnosis and prediction system is developed and realized with .NET 3.0, and condition prediction methods are applied to industrial field. Practical application vertifies this architecture is effective and useful.
  • LIU Lu-ming; LING Zhi-hao
    Computer Engineering. 2010, 36(1): 236-238. https://doi.org/10.3969/j.issn.1000-3428.2010.01.082
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    Aiming at the problems of high-power consumption for Wireless Sensor Network(WSN) node in industrial applications, a design scheme of wireless temperature transmitters for industrial applications with large measurement range and low power consumption is presented. Low-power chips are used in the circuitry and the sleep mechanism is applied to lower the node’s power consumption. The transmitter node can be used to measure temperature signals ranging from -50°C to 900°C. Experimental results show this scheme is feasible and effective.
  • LIU Di; BO Yu-ming; ZHAO Gao-peng
    Computer Engineering. 2010, 36(1): 239-241. https://doi.org/10.3969/j.issn.1000-3428.2010.01.083
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    According to the working mode of GPS software receiver to do signal process on data block, this paper studies fast acquisition and tracking technology for fake code of circular correlation method based on Fast Fourier Transform(FFT). Based on CPS intermediate frequency data getting by operational test, circular correlation method is used to calculate correlation value of input signal and local signal in frequency domain. Fine carrier frequency is obtained by phase relation. Simulation results show that this technology can reduce computation quantity and shorten acquisition time. The obtained carrier frequency can meet the tracking loop’s demand about frequency resolution. Navigation information can be obtained through sub frame match and parity check of tracking result.
  • PAN Yu-lin; YAO Xin-yu; KONG Ya-qiong; HUANG Ke-di
    Computer Engineering. 2010, 36(1): 242-244. https://doi.org/10.3969/j.issn.1000-3428.2010.01.084
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    Aiming at the High-Speed Real-Time(HSRT) demand of real-time simulation system, this paper proposes HSRT simulation system architecture based on multi-DSP. Under the multi-DSP environment, it realizes data transfer under different transfer protocols based on Link port. Performance test results show that Link port can realize high-speed and steady data transfer, and different transfer protocols provide realization methods for data transfer with different demands.
  • LI Xiao-jing; ZHANG Kan-yu
    Computer Engineering. 2010, 36(1): 245-247. https://doi.org/10.3969/j.issn.1000-3428.2010.01.085
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    This paper designs and realizes group control system for greenhouse based on CAN-bus and introduces the communication structure of group control which uses CAN-bus. It analyzes the hardware and software design of greenhouse environment control system. Results show that the monitor of the I/O equipment and the stable running of greenhouse control system can be realized by the application of multiple hosts working mechanism of CAN. It runs the system in a greenhouse is presented and obtains good effect.
  • HE Tao; XIE Jun; WANG Wen-juan; LI Yue-juan
    Computer Engineering. 2010, 36(1): 248-250. https://doi.org/10.3969/j.issn.1000-3428.2010.01.086
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    This paper introduces the mission flight simulation system for Unmanned Aerial Vehicles(UAV) based on Multigen simulation softwares including Multigen Creator, Creator Terrain Studio and Vega Prime. It establishes UAV flight control function in Vega Prime, and realizes the six-DOF motions of UAV model in virtual simulation scene. Real-time application of the system is realized based on multithread programming technology in the .NET 2003 environment and SBS data transfer. Simulation results show that the system can well simulate UAV battle flight mission.
  • Developmental Research
  • LIU Jie; YI Mao-xiang
    Computer Engineering. 2010, 36(1): 251-252,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.087
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Traditional adder must do several times of cyclic addition operation in processing of multi-operand accumlation. Aiming at this problem, this paper designs a five addend parallel adder and its high speed carry interface. Because the circuit uses parallel own department addition of multi-operands and bottom layer carry cascade connection transmission mode, the parallel operation between multi-operands is realized and addition times are reduced. Simulation results verify the design reasonability of the adder and prove that it can shorten addition time, enhance operation efficiency.
  • XING Xiang-lei; ZHOU Yu; DU Si-dan
    Computer Engineering. 2010, 36(1): 253-255. https://doi.org/10.3969/j.issn.1000-3428.2010.01.088
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    High efficient power management scheme is implemented to reduce the embedded system’s power consumption. An integrity power management software system is designed and implemented based on Advanced Power Management(APM) technology with adding the bootloader’s support for the power management, modifying the Linux kernel’s code to support the power management for the S3C2440 processor and system’s peripheral equipment, creating a user space daemon for power management. Experiment is done on the YLP2440 development board and the experimental results show that this power management system can reduce the power consumption to 11.67% and 12.96% respectively in two typical system frequency as that of the former in the idle state.
  • MING Guang-zhao; ZHANG Da-long; LI Ou
    Computer Engineering. 2010, 36(1): 256-259. https://doi.org/10.3969/j.issn.1000-3428.2010.01.089
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    This paper gives some key technologies in software design for Wireless Sensor Networks(WSN) node in health care system, including technology of nesC language based on TinyOs, design technology of MAC in special applied situation, and technology of energy conservation. It validates the health care system node which uses these design technologies has high reliability of data communication and low power with laboratory works.
  • HUANG Yang-bo; LIU Wan-jun; LIU Hui
    Computer Engineering. 2010, 36(1): 260-261,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.090
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    This paper takes a locomotive depot repair parts Automated Storage and Retrieval System(AS/RS) as an example, through analysis of important factors about double deep stack crane system, it proposes a optimized design based on the shortest operating time, establishes a mathematical model, and uses the Genetic Algorithm(GA) which adopts districted average search initial population method to carry on the experimental verification. Result proves that the optimized design can actually increase work efficiency of double deep stack crane AS/RS.
  • LOU Ning; LIU Ya-qi; QI Feng
    Computer Engineering. 2010, 36(1): 262-264. https://doi.org/10.3969/j.issn.1000-3428.2010.01.091
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    The method of Computer Generated Forces(CGF) is used in current command training simulation system. It makes trainee feel untruthful. Aiming at this problem, this paper presents a method of utilizing Real Forces(RF) and CGF to support the command simulation training together. It can increase the fidelity and level of training. It also can realize the goal of training accord with war. This paper presents the definition of RF, which is connected to information warfare command training simulation system, and discusses the design scheme and the key component of the system.
  • DAI Bei; LUO Jiang-tao
    Computer Engineering. 2010, 36(1): 265-266,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.092
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    The function of message filter of traditional network test instrument is achieved by xml or ini configuration file, since condition of complex combinational logical is required for filtering by Time Division-Synchronous Code Division Multiple Access(TD-SCDMA) network test instrument. The Lua scripting language is adopted and the function of supporting the condition of complex combinational logical is completed by calling the Lua functions and registering C functions to the Lua scripts. Test results show that the scheme meets functional requirements of instrument well, and achieves the desired goal.
  • HUANG Dong-jin; LAN Jian-liang; LIU Wu; DING You-dong
    Computer Engineering. 2010, 36(1): 267-270. https://doi.org/10.3969/j.issn.1000-3428.2010.01.093
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    To address the problem of rendering massive data in real time difficultly, a real-time predictive schedule strategy based on viewpoint for large-scale point-cloud data is proposed, that is, “5-5-5” dynamic schedule strategy. The entire three-dimensional point-cloud is processed into “district-subblocks”. And these subblocks are saved in the server database after multi-resolution compression. According to the changes of the view parameters and diamond-shaped schedule, subblock data can be scheduled dynamically and rendered in real time. The server is asked for transmitting the data expected to the client. Experimental results show that the algorithm effectively alleviates jitters and reduces one-time transmission payload from server, with good achievement of continuity and smoothness in process of roaming.
  • ZHOU Jing-di; CHENG Dong-nian; LIU Qing-rang; ZHANG Zhen
    Computer Engineering. 2010, 36(1): 271-273,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.094
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    Aiming at the problem of huge memory consumption and poor scalability of distributed packet classification algorithm, this paper proposes distributed tuple space crossproducting algorithm. This algorithm uses a classification structure with independent field search engines and dendriform multilevel aggregation network, employs Counting Bloom Filter(CBF) in aggregation nodes to accelerate searching process, and utilizes pruning technology to reduce the memory consumption of CBF. Simulation results indicate that the total memory consumption of aggregation network is below 60 Kb when handling 9-field filter set of 5×104, the searching speed of this algorithm is 100 Mp/s, and the algorithm achieves better scalability.
  • LIU Juan; OUYANG Yi-ming; LIANG Hua-guo
    Computer Engineering. 2010, 36(1): 274-276. https://doi.org/10.3969/j.issn.1000-3428.2010.01.095
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    A new test data compression technique based on encoding series and alternation sequences is proposed. It is a variable-to- variable-length code based on encoding lengths of runs of 0 s and 1 s, as well as alternating bits in test sequences. The code word consists of prefix and tail, the scheme uses prefix to indicate the type of sequence. Due to its simple architecture, the additional hardware overhead that the decompression circuit requires is very small. Experimental results for the ISCAS’89 benchmark circuits show that this technique can efficiently compress test data.
  • ZHOU Shui-hong; DUANMU Chun-jiang; HUANG Zhi-liang; CHEN Xing
    Computer Engineering. 2010, 36(1): 277-279,. https://doi.org/10.3969/j.issn.1000-3428.2010.01.096
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    Aiming at the problem quasi-cyclic Low-Density Parity-Check(LDPC) code has an efficient encoding algorithm, the degree distribution of the code usually can not satisfy the optimal degree distribution. This paper disposes the distribution of unit cyclic shift matrix in check matrix, improves the method for constructing check matrix. Simulation results show that improved construction method has efficient encoding algorithm, makes the code with approximate optimal degree distribution, and the code has better performance under the condition of the same code length.
  • WANG Feng; WANG Wei; ZHANG Jing; LUO Zuo-min
    Computer Engineering. 2010, 36(1): 280-282. https://doi.org/10.3969/j.issn.1000-3428.2010.01.097
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    In view of current key aspects that affect the crawler system efficiency, through research of crawler system interior movement mechanism, this paper optimizes the overhead construction and improves its algorithm. In the Linux network environment, through movement examination of the crawler system, it may feed back several kinds of solutions and improvement place which are feasible, and it also enhances the efficiency and the crawler system overall performance.
  • DING Ya-tao
    Computer Engineering. 2010, 36(1): 283-封三. https://doi.org/10.3969/j.issn.1000-3428.2010.01.098
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    This paper proposes a new paper distribution model based on traditional C/S model. This model makes full use of the network bandwidth and allows to download papers packet from other client, thereby effectively reduces the load of server. Experimental result shows that this model pays less time to download paper, it solves the problem of bottleneck when creating paper at the same time, makes the system running on inefficient network.