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05 July 2011, Volume 37 Issue 13
    

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    Networks and Communications
  • LIAO Yong, WANG Cong, WANG Dan, XU Chang-Biao
    Computer Engineering. 2011, 37(13): 1-4. https://doi.org/10.3969/j.issn.1000-3428.2011.13.001
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    The existing TCP mechanisms can not effectively distinguish the cause of packet loss in wireless networks whether it is triggered by congestion or deafness. In order to solve the problem, this paper proposes a Cross-layer Explicit Deafness Notification(CLEDN) in wireless Mesh network. It adopts Media Access Control(MAC) based on busy tones when system uses directional antennas, and an explicit notification frame is designed between IP and TCP, which is passed to source node through the user-defined multi-hop forwarding rule. The mechanism is applied to theoretical deduction and analysis in linear wireless Mesh networks, and numerical analysis verifies its feasibility and validity.

  • WANG Lin-Chao, ZHANG Xin-Wei
    Computer Engineering. 2011, 37(13): 5-8. https://doi.org/10.3969/j.issn.1000-3428.2011.13.002
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    Aiming at the micro-mobility feature of Mobile Ad hoc Network(MANET) nodes, micro-mobility management strategy is presented in the design of MANET gateway which employs the Ad hoc On-demand Distance Vector(AODV) routing protocol. Micro-mobility management is applied to the route sub-layer of network layer in MANET and implemented in AODV routing protocol. Simulations result of NS2 platform shows that the MANET gateway which employs the micro-mobility management strategy can reduce the end-to-end delay and the consumption of control packets of MANET accessing the Internet effectively.

  • HE Yao-Ban, LI Xiang-He, SUN Yan
    Computer Engineering. 2011, 37(13): 9-12. https://doi.org/10.3969/j.issn.1000-3428.2011.13.003
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    In order to get new file hidden points in drive-level of system, the principle of File System Filter Driver(FSFD) and the structure of driver stack location are analyzed. Through making some changes in driver stack location’s structure and CompletionRoutine, besides modifying the I/O Requst Packet(IRP) delivery method, two methods to hide files are implemented. Hidden files using these methods achieve depth hide. They can not be queried by system or be accessed through normal channels.

  • DUAN Xin, CHEN Li-Guang, WANG Jian, LAI Jin-Mei, BAO Li-Chun
    Computer Engineering. 2011, 37(13): 13-16. https://doi.org/10.3969/j.issn.1000-3428.2011.13.004
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    This paper proposes the design and implementation of a System on Programmable Chip(SoPC) interface to solve the problems of timing control and bit stream downloading of embedded Field Programmable Gate Array(FPGA) IP core in the evolvable SoPC. The FPGA interface uses asynchronous FIFO and dual port RAM structure, scalable read/write command transmission to achieve asynchronous communication between FPGA IP core and the system. Embedded CPU achieves the on-chip bit stream configuration of FPGA IP core via FPGA interface. Hardware random number generator in the FPGA interface is used to accelerate the evolutionary algorithm. Automatic verification platform and FPGA prototyping platform are used for the verification of FPGA interface to achieve convergence of verification. Test results show that FPGA interface implements the communication between embedded CPU and FPGA IP core successfully, completes on-chip evolution.

  • BAO Lin-Chao, CA Chao, XIAO Ji, ZHOU Cheng-Beng
    Computer Engineering. 2011, 37(13): 17-19,25. https://doi.org/10.3969/j.issn.1000-3428.2011.13.005
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    A new visual attention model used for rapid perception of complex targets in natural scene is proposed. In the learning process, the model extracts saliency blobs from a given target’s image. Then during the process of attention on a scene image, it adopts a blob searching and merging strategy based on graph matching to guide visual focus to where it looks like the target. The blob searching and merging strategy uses features of learned heterogeneous blobs and their spatial relative positions, which are all recorded during the previous target learning process. Compared with typical bottom-up visual attention model, experiments show that the new method could efficiently introduce feature and structure information of complex target into the process of attention, reduce useless visual focus shifts, and improve the performance of visual attention. The model could be used to locate complex structural targets in natural scene images.

  • SU Hang, XUE Pan-Chao
    Computer Engineering. 2011, 37(13): 20-25. https://doi.org/10.3969/j.issn.1000-3428.2011.13.006
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    To solve the problem of the data transmission speed mismatch between I/O device and CPU, this paper analyzes the efficiency of various buffer structure based on computer architecture. With QuartusII which is Computer-Aided Design(CAD) using Electronic Design Automation(EDA) software, it designs the asynchronous dual-clock First In First Out(FIFO) buffer, including the buffer structure of the simulation, data recording, and analysis of its effectiveness. Analysis results show that the efficiency of computer system is closely related with that of FIFO. To improve the efficiency of computer system, the efficiency of FIFO is supposed to be improved first. At the same time, the improvement of the efficiency of FIFO is based on the improvement of the efficiency of computer system.

  • CHEN Hong, CHEN Yao-Wu
    Computer Engineering. 2011, 37(13): 26-28,32. https://doi.org/10.3969/j.issn.1000-3428.2011.13.007
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    In order to detect the content errors which conform to syntax standard while video contents have changed through 3G wireless networks, an error detection algorithm based on compressed domain and pixel domain spatial correlation for H.264 is proposed. The algorithm uses the similarity of neighboring Direct Current(DC) coefficients in compressed domain and neighboring reconstruct pixels in pixel domain to detect whether there is an error in one macroblock. Experimental result shows that, under different error rate and different streams, the proposed algorithm can detect content errors effectively and improve the reconstruct image quality significantly.

  • LI Yao-Yao, GU Jin-An, LIU Qiong
    Computer Engineering. 2011, 37(13): 29-32. https://doi.org/10.3969/j.issn.1000-3428.2011.13.008
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    Traditional cache replacement strategy lacks pertinence to the semantic cache, and it can not reuse the data in cache effectively, it affects the performance of the cache. This paper proposes an eXtensible Markup Language(XML) query cache replacement strategy based on semantic contribution value for the characteristics of XML query algebra. It processes cluster analysis according to the cache item of user history query, forecasts the semantic contribution values of future query, and replaces the item which has minimum value of semantic contribution in insufficient space. Experimental results show that this strategy can effectively shorten the inquires time, and improves cache hit than both Least Frequency Used(LFU) and Least Recently Used(LRU).

  • LI Wen-Long, CHANG Diao-Wei, ZHANG Ling-Feng, WANG Jie, HU Qing-Xiong
    Computer Engineering. 2011, 37(13): 33-35,39. https://doi.org/10.3969/j.issn.1000-3428.2011.13.009
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    In order to improve the accuracy of Chinese off-line handwriting recognition, this paper proposes a method based on magnitude and relative phase information of Pyramidal Dual-tree Directional Filter Bank(PDTDFB). Derived Magnitude Distribution(DMD) and relative phase depicted by Von Mises(VM) distribution and Wrapped Cauchy(WC) distribution model are introduced to reflect the features of image in detail, and Resistor-average(RA) distance is applied. According to the idea of Multiple Attribute Decision Making(MADM), the two kinds of features extracted from magnitude and relative phase are fused in the algorithm. Experimental results show that in comparison to Generalized Gaussian Density(GGD) model with PDTDFB, the accuracy of the method increases by 2.2%.

  • SUN Guo-Fei, GU Jian-Hua, HU Jin-Hua, DIAO Tian-Hai
    Computer Engineering. 2011, 37(13): 36-39. https://doi.org/10.3969/j.issn.1000-3428.2011.13.010
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    Aiming at longer time and memory pages repeated retransmission in the process of memory pre-copy, this paper optimizes the mechanism of memory pre-copy migration and uses Markov prediction model to improve the algorithm that reckon the working set of memory dirty page, designs an new algorithm that calculate working set of memory dirty page by forecasting the probability of dirty pages. This algorithm calculates probability of being modified next round of iteration using dirty pages history of the operation visits, only the memory pages with a lower probability can be translated. Experimental results show that new algorithm shortens the total time of migration and downtime, and effectively support dynamic migration of Virtual Machine(VM).

  • GUO Feng-Yu, LEI Yu-Tong, CHEN Hai-Chao, HU Wei
    Computer Engineering. 2011, 37(13): 40-42. https://doi.org/10.3969/j.issn.1000-3428.2011.13.011
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    Based on Business Process Execution Language(BPEL), this paper adopts stateless Web services and describes business process as Colored Petri Nets(CPN), which designs a Multiple Input and Multiple Output(MIMO) process running structure in the centre of engine, using associated matrix and bidirectional message transfer to do application-level state preservation. When the process is interrupted, the engine provides a minimum set for state recovery. It makes the Service-oriented Architecture(SOA) process based on Web Services BPEL(WS-BPEL) accurate and continuous. Example analysis results show that this method has good practicability and high reliability
  • XU Jian-Min, CHEN Zhen-E
    Computer Engineering. 2011, 37(13): 43-45. https://doi.org/10.3969/j.issn.1000-3428.2011.13.012
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    This paper analyzes the representation method and characteristics of retrieval, studies a Bayesian network for structured document retrieval. It discusses the construct method and probability estimates of Bayesian network, and the retrieval process. Index terms and structural units can be represented by nodes, relationship among nodes can be described by arcs, and prior probability of nodes can be estimated according to TF-IDF. The relevance of each structural unit can be computed and ranked by its conditional probability when a user query is given. Example proves the effectiveness of the Bayesian network.
  • TUN Hua-Yan, HUANG Dao-Beng
    Computer Engineering. 2011, 37(13): 46-48,51. https://doi.org/10.3969/j.issn.1000-3428.2011.13.013
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    In order to retain shape and tend features during the clustering process, this paper proposes a data stream clustering method based on shape feature. In the initialization stage, the subsequence is represented with the important points. In the online update stage, Partial Dynamic Time Warping(PDTW) method is used to compute the distances between the subsequences and ensure the data synchronization using the dynamic sliding window. In the clustering stage triggered by the user, the data streams clustering method is proposed. Experimental results show that the shape-based clustering over data streams can get the evolution accuracy of 0.95 with the reasonable parameters.
  • LI Jian-Jie, XI Hong-Sheng, DAN Yong-Ge
    Computer Engineering. 2011, 37(13): 49-51. https://doi.org/10.3969/j.issn.1000-3428.2011.13.014
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    Based on the Skyline computation algorithm of static data in Chord network and Skyline computation algorithm in distributed environment, this paper proposes a Skyline computation algorithm of dynamic data in Chord network. It realizes real-time update of data through the model of window, and users can get their real-time and interesting information more accurately. Theoretical analysis and experimental results prove that this algorithm realizes load balance of network, has good progressive and can effectively reduce consume of network bandwidth.
  • CHEN Wei, MO Yao-Beng, CHEN Shu-Qiao
    Computer Engineering. 2011, 37(13): 52-54. https://doi.org/10.3969/j.issn.1000-3428.2011.13.015
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    Traditional pattern matching algorithms can not process packet at line-speed under the high speed environment. This paper presents a fast multi-pattern matching algorithm based on Ternary Content Addressable Memory(TCAM) which cuts long pattern to short sub-string stored in the first TCAM by pattern shifting, and stores number in the second TCAM. In the search pattern process, the first TCAM returns the number of matching entry, the second TCAM matches the serial numbers and gives long pattern matching information. This paper proposes a space dividing method to compress the number of TCAM entries and improves the utilized rate of resources. Experimental results show that this algorithm can achieve high-speed packet processing and has lower space consumption compared with the pattern-shifted storing algorithm based on hash mark.
  • CHEN Zhen-Qiang, LUO Lan-Hua
    Computer Engineering. 2011, 37(13): 55-57,60. https://doi.org/10.3969/j.issn.1000-3428.2011.13.016
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    The dynamic dimension is introduced by Dynamic Description Logics(DDL) on the basis of traditional description logics. It possesses powerful expression ability of static structure and dynamic behavior. According to the characteristics that Unified Modeling Language(UML) statechart includes static semantics and dynamic semantics, a formal methodology for UML statechart based on dynamic description logics is proposed, and the syntax and the semantics of DDL DDL_SHOIN(D) is presented. A formal methodology that using DDL_SHOIN(D) to formalize UML statechart is given out, and the action reasoning problems of the statechart are studied. The state accessibility and the subsumption definitions of the statechart behavior are put forward. The validity of the definitions is proved.
  • FANG Gang, XIONG Jiang
    Computer Engineering. 2011, 37(13): 58-60. https://doi.org/10.3969/j.issn.1000-3428.2011.13.017
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    Redundancy candidate sets and repeated computation usually exist in traditional constrain rule mining algorithms with application to mining frequent neighboring class set with constrain condition. Hence, this paper proposes an algorithm of mining frequent Neighboring Class Set(NCS) with constrain condition, which is suitable for mining frequent neighboring class set with constrain spatial objects in spatial database. To improves mining efficiency of algorithm, the algorithm uses double alteration of identity value of neighboring class set to generate candidate frequent neighboring class set, and it also uses AND operation of identity value to compute support. Experimental result indicates that the algorithm is much simpler and faster than present algorithms.
  • CA Liang, LIU Teng
    Computer Engineering. 2011, 37(13): 61-62,65. https://doi.org/10.3969/j.issn.1000-3428.2011.13.018
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    Most of current Database Management System(DBMS) provide a mater and slave asynchronous replication mechanism, when the master node fails, the whole system will breakdown, and the potential delay between mater and slave will causes data lose. This paper provides a write set based synchronous database replication model on the basis of group communication replication, which can solve the delay problem, and improve the availability and extendibility in distributed databases.
  • SONG E-Nan, ZHONG Qian, ZHONG Yuan
    Computer Engineering. 2011, 37(13): 63-65. https://doi.org/10.3969/j.issn.1000-3428.2011.13.019
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    This paper proposes an ontology instance matching algorithm based on multi-property. The approach obtains the similarities between instances. And then for the initial matching results, the method uses the Similarity Flooding algorithm to revise these similarities according to the directed graph constructed by the object properties. The necessity properties are employed to filter out the incorrected matching pairs. Experimental results show that the proposed method can increase the precision ratio and recall ratio of ontology instance matching.
  • ZHANG Lin, CHEN Yan, LI Tao-Ying, MAO Xiang-Wei
    Computer Engineering. 2011, 37(13): 66-67,70. https://doi.org/10.3969/j.issn.1000-3428.2011.13.020
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    ID3 algorithm tends to choose the attributes of more values as the splitting attributes. Aiming at the problem, this paper introduces two parameters including attribute importance and number of attribute values to improve the existed formula of information gain of ID3 algorithm. This contributes to enhancing the importance of the critical attributes with fewer values and making the algorithm better reflect the actual decision-making situation. According to the properties of the convex function, it simplifies the calculating formula of information entropy to improve the efficiency of constructing a decision tree. A concrete example is given to describe the specific application of improved algorithm, and the result shows that it is more efficient than the original algorithm.
  • LI Qiang-Gong
    Computer Engineering. 2011, 37(13): 68-70. https://doi.org/10.3969/j.issn.1000-3428.2011.13.021
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    Traditional accurate query of mass data is easy to lead to overload. Aiming at this problem, this paper uses Bootstrap method of the confidence interval based on the simulation to provide database support. The method reduces the range of query data by querying part or sample data instead of all data sets for simplifying basic data of the query. The time of querying all data sets can complete repeated queries for multiple samples, the confidence bound of the database query should be obtained. Employing a basic Structured Query Language(SQL) query gets the approximation results, which correspond to user demand. Experimental result shows that the Bootstrap method is effective for querying data.
  • LI Xiu-Hua, XIE Jiang, DING Qiu-Lin
    Computer Engineering. 2011, 37(13): 71-73,82. https://doi.org/10.3969/j.issn.1000-3428.2011.13.022
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    Collaborative construction of ontology is a very complicated task. It often requires many developers to work collaboratively. However, current ontology development tools and methods are lack of supporting to it. Therefore, a concurrent control method based on lock subdivision is proposed, which divides nodes into some smaller units according to the operations to nodes, making the minimal granularity of lock be the operation unit of nodes, and also subdivides the lock, according to the operation type, locks the correspondent unit. Furthermore, the locking algorithm is designed. Application result shows that this method can effectively improve concurrency and integration of the collaborative development.
  • XIE Peng-Yu, SONG Ling, CHEN Yan
    Computer Engineering. 2011, 37(13): 74-76. https://doi.org/10.3969/j.issn.1000-3428.2011.13.023
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    It is necessary to research new routing protocols for Multi-interface Multi-channel(MIMC) Wireless Mesh Network(WMN), but the NS2 simulator is no longer adapted to the MIMC simulate environment. The paper takes MIMC-AODV for example to introduce the key points of its extension procedures. A new evaluation parameter-channel utilization, power control methods for WMN and a power control method are proposed for WMN. Experiment is done under one scene especially for the WMN.
  • HU Jian-Zhen, SHANG Jin-Bei, ZHANG Qian
    Computer Engineering. 2011, 37(13): 77-79. https://doi.org/10.3969/j.issn.1000-3428.2011.13.024
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    For the lack of an effective group member management, this paper presents a group member management model for large-scale application layer multicast, which is based on Lightweight Directory Access Protocol(LDAP) uniform identity authentication system, using distributed directory service design, directory partition, directory recommendation, and directory replication for the efficient and unified management of directory information which are distributed in different physical location, and combining the authentication technology with the trust model. Simulation experimental results show that SAGM can effectively improve the average rate of data transmission and enhance the performance of security.
  • YANG Zhen-Qi, YANG Yun-Xue
    Computer Engineering. 2011, 37(13): 80-82. https://doi.org/10.3969/j.issn.1000-3428.2011.13.025
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    Aiming at the problem of manual selection of Area Border Router(ABR) can not satisfy the dynamic change in the network load in Open Shortest Path First(OSPF) protocol. This paper proposes a new algorithm of the dynamic appointment of ABR for OSPF. Based on observed traffic demands and knowledge on link capacities, the proposed algorithm locates an adequate ABR for the new traffic pattern to avoid incipient link congestion and accompanying performance degradation. NS2 simulation results show that the proposed algorithm gets a better performance at parameters such as end-to-end delay and packet loss rate.
  • BANG Shi-Zhang, DIAO Ze-Mao, BAO Jian-Rong, CAO Hai-Yan
    Computer Engineering. 2011, 37(13): 83-85,88. https://doi.org/10.3969/j.issn.1000-3428.2011.13.026
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    Based on the structure of parity-check matrix of RU algorithm, a class of Quasi-cycle Low-density Parity-check (QC-LDPC) codes with complexity is constructed by selecting sub-matrices reasonably to restrict and consisting of lower dual diagonal matrices. Simulation results show that not only the proposed codes have lower complexity, but also the error-correcting performance is better than QC-LDPC codes randomly constructed and practical Block-LDPC codes in the additive white Gaussion noise channel. It can get 0.3 dB Signal to Noise Ratio(SNR) gain at a Bit Error Rate(BRE) of 10-6.
  • DIAO Chao, TANG Hua-Wen, ZHANG Hai-Long
    Computer Engineering. 2011, 37(13): 86-88. https://doi.org/10.3969/j.issn.1000-3428.2011.13.027
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    Aiming at the limitations on the reorganization of ID fields with mark in the IP packets, such as the inconsistency in the ID values and the ID field is illegally altered. A path reconfiguration strategy based on IPv4 options packet marking is proposed and used to reconfigure the attacking paths. Compared with the traditional ID-based marked strategy, the number of mistaken router nodes is less and the complexity is lower adopting this strategy. In addition, it possesses obvious advantages in the packet processing time of routers.
  • LEI Shu-Pei, XIONG Yong, YANG Xiu-Mei
    Computer Engineering. 2011, 37(13): 89-91,94. https://doi.org/10.3969/j.issn.1000-3428.2011.13.028
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    This paper studies a generation method of Random Access(RA) signal in physical layer of the Long-Term Evolution(LTE) system. Based on the key technical characteristics of random access, including Zadoff-Chu(ZC) sequences, SC-FDMA principles and baseband signal generation, it proposes to use a practical method to generate RA signal by using up-sampling and Low-Pass Filtering(LPF). Complexity analysis shows that this method can greatly decrease the complexity in signal generation, which is very valuable in engineering practice. Simulation results show that the signal generated by this method is very close to the signal generated using direct theoretical Inverse Fast Fourier Transform(IFFT).
  • TANG Chao-Wei, ZHOU Dun-Feng, SHAO Yan-Qing, TANG Hui
    Computer Engineering. 2011, 37(13): 92-94. https://doi.org/10.3969/j.issn.1000-3428.2011.13.029
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    Wireless sensor network has the following features, such as large-scale topology, Mesh networking, the limited energy of nodes, poor processing ability. Global routing optimization algorithm is presented in this paper. The proposed algorithm can prevent the occurrence of network congestion by selecting the different value of the variable r to get different output-path. Simulation results show that the processing time of this algorithm is only the third of that of Dijkstra algorithm. At the same time, it can not only meet the routing requirements of wireless sensor networks, but also solve the congestion problem of wireless sensor networks.
  • LIU Dun, XIE Hua
    Computer Engineering. 2011, 37(13): 95-97,106. https://doi.org/10.3969/j.issn.1000-3428.2011.13.030
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    TCP Reno congestion control mechanism based on the algorithm of Additive Increase Multiplicative Decrease(AIMD) is mainly used in the Internet in the present. Aiming at the drawback of this algorithm in dealing with the detection of available bandwidth utilization rate due to AIMD factors too arbitrary, traditional AIMD algorithm is researched and a smooth channel capacity detection algorithm based on the growth of a congestion window is proposed, its throughput, fairness and friendliness are evaluated by NS simulation. Simulation results show that the throughput of modification algorithm of TCP outperforms TCP Reno by 10%.
  • LIN Xiao-Yong, XU Ming-Hai, LV Jun, WANG Fa-Feng
    Computer Engineering. 2011, 37(13): 98-100. https://doi.org/10.3969/j.issn.1000-3428.2011.13.031
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    According to the management problems of complex operator’s Broadband Access Network(BAN), this paper proposes an improved general topology discovery algorithm. The corresponding configuration log files are obtained in Telnet mode by means of multithreading visits, and then interpreted. The parameters are stored in the database. The basic principle is that the physical Media Access Control(MAC) address of lower layer Network Element(NE) is mapped in the address forwarding tables of upper layer NE. It triggers from one access switch as leaf node, ended with Broadband Access Server(BAS) switches as root node, which makes a sole physical topological path. Double uplink of logical topology discovery is solved because the algorithm executes only between the convergence layer and BAS layer. And a method for verifying the correctness of the generated topological data is presented.
  • LIANG Min, CHANG Chao-Wen, FAN Xue-Zhu
    Computer Engineering. 2011, 37(13): 101-103. https://doi.org/10.3969/j.issn.1000-3428.2011.13.032
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    In order to improve the performance of the full disk encryption system, this paper studies and analyzes the existing disk encryption algorithms and modes, and tests the performance of different combinations of encryption algorithms and modes. The ways of encryption storage are introduced. The existing encryption algorithms and modes are analyzed. The performances of encryption algorithms and modes are tested and analyzed. A suggestion is proposed for full disk encryption. Result provides referential basis for designers of encryption storage.
  • XIE Yu-Xin, LIU Yan-Hang, SHU Jian-Qi, SUN Xin, FU Feng
    Computer Engineering. 2011, 37(13): 104-106. https://doi.org/10.3969/j.issn.1000-3428.2011.13.033
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    A hybrid intrusion detection model is presented against the high false positive and false negative rate in Intrusion Detection System (IDS). This model constructs two feature extractors based on Kernel Principle Component Analysis(KPCA) and Kernel Independent Component Analysis(KICA), and uses a novel ensemble approach to learn the results produced by the extractors. It has capacity of processing large-scale data by using distributed neural network to learn the ensemble results, and obtains the optimal detection result by means of feedback regulating to change the ensemble learning weight. KDD CUP’99 is adopted in experiment and the result shows the model gets the lower false negative rate and false positive rate besides the higher accuracy.
  • WANG Jing, WANG Xiang-Yang
    Computer Engineering. 2011, 37(13): 107-108,112. https://doi.org/10.3969/j.issn.1000-3428.2011.13.034
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    There is a trade off between the imperceptibility and robustness of a digital watermark system. Trying to deal with this problem, a new digital image watermark method based on Human Visual System(HVS) is proposed. The geometrically invariant space is constructed by using image normalization, and a significant region is obtained from it. A readable watermark with size of 256 bit is adaptively embedded in the Discrete Fourier Transform(DFT) domain in accordance with the conceal quality of HVS. Especially, the predistortion compensation method is used to reduce image distortion generated by image normalization. This is a blind watermark algorithm to confirm the copyright without the original image. Experimental results show that the proposed scheme is not only invisible, but also robust against common signals processing and geometric attacks.
  • YANG Xiao-Gong, DU Hua-Gui, CAO Li-Feng
    Computer Engineering. 2011, 37(13): 109-112. https://doi.org/10.3969/j.issn.1000-3428.2011.13.035
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    Focusing on the problem of communication with traditional IPsec in Multi-level Security(MLS) network, this paper presents a solution about IPsec based on implicit security label. This solution solves the problem by adding implicit security label in IPsec, improving the processing of IKE, ESP protocol, binding the IPsec SA and implicit security label, selecting different algorithms and keys based on different information. It sets up different levels of labeled tunnels dynamically, and realizes the isolation of different levels of data stream and security communication in MLS networks.
  • ZHANG Jian-Zhong, LI Rui, JIAO Xiao-Lin
    Computer Engineering. 2011, 37(13): 113-114,118. https://doi.org/10.3969/j.issn.1000-3428.2011.13.036
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    Based on a vector space secret sharing scheme and the difficulty in solving the discrete logarithm problem, a group signature scheme without a trusted centre is proposed, which is constructed on general access structure. The scheme doesn't need the trusted KDC’s participation, and expands group signature’s application scope to the general access structure. It not only overcomes the applied limitation of the existing threshold signature schemes, but also avoids the KDC providing fake information to participants. In the implementation phase, individual signature and group signature can be verified efficiently. Analysis result shows that this scheme is secure and efficient.
  • ZHOU Jia-Jing, WANG Fu, CHEN Han-Hui, JU Xiang-
    Computer Engineering. 2011, 37(13): 115-118. https://doi.org/10.3969/j.issn.1000-3428.2011.13.037
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    Aiming at the problem that trust management puts emphasis on trust in Public Key Infrastructure(PKI) cross-domain scheme, the trust calculation is discussed under PKI. To adapt the dynamic changes in inter-domain trust features of PKI, a calculation method of PKI cross-domain trust is proposed, which makes the trust evaluation for foreign entities, after the resource domain sets trust relationships between the domain and external root CA, monitor behavior of external users is conducted. The calculation can evaluate the trust entities.
  • XIAO Hong-Fei, LIU Chang-Jiang
    Computer Engineering. 2011, 37(13): 119-121,124. https://doi.org/10.3969/j.issn.1000-3428.2011.13.038
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    The original authentication mechanism of Zimmermann RTP(ZRTP) is vulnerable to the Man In The Middle(MITM) attack in certain conditions, although it is a light-weighted and efficient key agreement protocol. This paper introduces a new algorithm named NSAKA to enhance the original mechanism, which is based on the basic concept of Simple Authentication Key Agreement(SAKA). The Session Initiation Protocol(SIP) identity authentication model of RFC4474 is also employed to securely transmit the users’ pre-shared secret password. The scheme can effectively enhance the ability to resist against the MITM attack of ZRTP and remedy the primary vulnerabilities of SAKA.
  • CHE E-Beng, HU Cheng-Wei, FANG Yong
    Computer Engineering. 2011, 37(13): 122-124. https://doi.org/10.3969/j.issn.1000-3428.2011.13.039
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    Trojan embedded in the Basic Input/Output System(BIOS) of computer has a tremendous hazard to the safety of computer system, and it is difficult to be discovered and removed. The structure, implanting methods and activation mechanism of BIOS Trojan are analyzed. The database of BIOS Trojan characters and standard BIOS samples are built, and a BIOS security detection system is designed and implemented in the paper so as to resolve the problem. The detection system can scan computer’s BIOS to defence BIOS Trojan and unknown malicious code, and it can enhance the security of the firmware in computer.
  • MA Jun-Yu, DIAO Zhi-Jin, XIE Hua-Xi
    Computer Engineering. 2011, 37(13): 125-127,131. https://doi.org/10.3969/j.issn.1000-3428.2011.13.040
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    Much more user behaviors evidence is needed in user behaviors assessment in trusted network. Low computational complexity and easily programmable are necessary to an assessment approach. Previous methods should be improved in the two performances. A new method is proposed to assess user behaviors. The optimal membership degree of user behaviors evidence and the weight of user behaviors evidence determined by fuzzy decision analysis theory are used to calculate the trust membership degree of the user behaviors. User behaviors are assessed by their trust membership degree. Experimental results show the method can be used to assess the practical network user behaviors availably both in the low computational complexity and easily programmable.
  • SUN Jian-Liang, ZHANG Yong-Zheng, YUN Xiao-Chun
    Computer Engineering. 2011, 37(13): 128-131. https://doi.org/10.3969/j.issn.1000-3428.2011.13.041
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    In view of existing work’s lack of scalability and uniformity, this paper presents an universal collaborative interaction model and system based on Von Neumann architecture for network security(UINAS). According to the UINAS, it implements a system and tests real data to verify system’s effectiveness. Experimental result shows that the UINAS and the system proposed in this paper are of good universality, scalability, applicability and they can effectively accomplish single and multi source collaborative interaction tasks, find associations between multi-source security events.
  • BIAN Li, CHEN Xing-Yuan, HONG Yong-Wei
    Computer Engineering. 2011, 37(13): 132-134,138. https://doi.org/10.3969/j.issn.1000-3428.2011.13.042
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    To resolve the common problems that the hierarchy management and control of files is weak and coarse-grained by using traditional technology in file protection, combining the multi-dimensional and multistage application environments of files, a file classified protection model based on multi-dimensional label is proposed. It combines the static characteristics label with the dynamic confidentiality label organically and introduces the concept of domain label. The security of the model is proved. Analysis and application results show that access to files in different environments can be effectively controlled without influence of normal use, thus this model can ensure the security of files.
  • OU Yang-Kang, ZHANG Gan-Ling
    Computer Engineering. 2011, 37(13): 135-138. https://doi.org/10.3969/j.issn.1000-3428.2011.13.043
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    Asmuth-Bloom(AB) algorithm is a robust software watermark algorithm based on threshold scheme, which is originally used to secret sharing, so there is no restriction on sub-key’s length. With an expanded threshold scheme, sub-key’s length can be reduced. A new algorithm based on expanded threshold is proposed. Moreover, a new watermarking system is implemented on the Java platform by using dynamic graph. Experimental results show that the proposed method can reduce the data expansion, and make the recovery process easier. The conditions above mentioned are suitable for practicalized watermark system.
  • BAI Jun, ZHANG Min-Rui, LIANG Wen-Chi
    Computer Engineering. 2011, 37(13): 139-140,149. https://doi.org/10.3969/j.issn.1000-3428.2011.13.044
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    An image watermark embedding algorithm is presented. Harris operator is used to extract several feature points of the host image, about some of which non-overlapping square regions centres. Wavelet transform is done within the square regions and the watermark is embedded in the low-frequency coefficients. Experimental results show the algorithm has good transparency and better robustness, especially in JPEG compression and cropping attacks. It can be used for image copyright protection.
  • RAO Meng-Liang, CA Huan-Dong, DING Yao-Jun
    Computer Engineering. 2011, 37(13): 141-143. https://doi.org/10.3969/j.issn.1000-3428.2011.13.045
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    This paper presents an algorithm that detects HTTP tunnel based on Support Vector Machine(SVM). It obtains feature fields to generate training sets for building classification model using SVM, and combines famous address matching and the direction selection of HTTP flow to detect the HTTP tunnel traffics. The algorithm is compared with the related algorithm, and the results show it does not use the probability distribution of sample space. It is steady and effective which can detect the HTTP tunnel traffics with high hit ratio.
  • BO Wei, YANG Na-Fei, AN Rong
    Computer Engineering. 2011, 37(13): 144-146. https://doi.org/10.3969/j.issn.1000-3428.2011.13.046
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    A new method based on horizontal gradient and morphology is proposed for the location of low-quality license plate. An adaptive threshold segmentation algorithm for horizontal gradient image is used to obtain useful gradient information of the image, then the adjacent candidate regions are obtained by morphological operation and region merging. The rough location result of the license plate is obtained by search candidate regions according to the characteristics of the plate. The accurate region of the plate is obtained by the line scanning method. Experimental result shows that the algorithm is robust for the location of low-quality plates taken under the environment of low illumination, serious noise, slanting plate or partial pollution and can meet the demand of real-time traffic.
  • CHENG Jian-Feng, LI Jun, LI Xiong-Fei
    Computer Engineering. 2011, 37(13): 147-149. https://doi.org/10.3969/j.issn.1000-3428.2011.13.047
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    Imbalanced Data Learning(IDL) problem is one of the research issues in machine learning. This paper presents a classification algorithm based on undersampling, which algorithm undersamples the majority examples, and retains the majority examples near the classify border. With the AUC as the optimization objectives. It chooses the most appropriate domain radius to balance the data set, and trains the Bayesian classifier by the use of the examples after undersampling. Using AUC as a measure of classifier performance evaluation, the experiments on simulation data and UCI data sets show that undersampling is effective.
  • XIE Bei, TU Yong-Quan
    Computer Engineering. 2011, 37(13): 150-152. https://doi.org/10.3969/j.issn.1000-3428.2011.13.048
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    Aiming at the problems of Evolutionary Programming(EP) such as premature convergence, slow convergence, this paper proposes an EP algorithm based on probe mutation. It can obtain a few mutational variables by reducing the dimensionality while fixating the others, and makes these individuals mutate which makes the individual always move forward to the direction with high fitness. By applying self-adaptive Gauss standard deviation to recover the search space, the individual has opportunity for jumping out the local optimum solutions. Experimental results show that the improved algorithm converges quickly, has high-quality solutions, and overcomes premature convergence problem.
  • LI Rui, YU Liu-Jing, LI Meng
    Computer Engineering. 2011, 37(13): 153-155. https://doi.org/10.3969/j.issn.1000-3428.2011.13.049
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    Aiming at the problem of Unscented Particle Filter(UPF) algorithm such as particles degeneracy and particles impoverishment, by comparing particles’ present values with the fitness value of objective function, it uses Particle Swarm Optimization(PSO) algorithm to make particles of UPF move towards the higher likelihood area, and finds the optimal position, and relieves the problem of particles degeneracy and impoverishment by improving re-sampling process. Experimental result proves that the state estimation precision of the improved algorithm is superior to traditional UPF algorithm.
  • LIU Fu-Yu, LI Jing, HONG Liu-Rong
    Computer Engineering. 2011, 37(13): 156-159. https://doi.org/10.3969/j.issn.1000-3428.2011.13.050
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    This paper proposes a shadow removal method based on edge feature. By using the edge information of the shadow which is obtained by edge detection algorithm the shadow of moving vehicle is removed by edge difference analysis and morphological operations. Then, a shadow removal method based on gray feature is proposed, which remove the shadow of vehicle using Gaussian darkening factor model. Combined with the advantages of two methods, a method of shadow removal for moving vehicle based on multiple feature fusion is proposed. It can effectively solve the problem of wrong detection caused by complex edges in shadow region and the similar color between vehicle and shadow. The testing results demonstrate that by using the proposed method shadow removal can be realized with real-time performance, strong robustness and high accuracy.
  • LIU Qing-Ji, CHEN Gui-Meng, LIU Xiao-Fang
    Computer Engineering. 2011, 37(13): 160-162. https://doi.org/10.3969/j.issn.1000-3428.2011.13.051
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    This paper analyzes the deficiency of genetic algorithm in solving matrix variable function, proposes a new genetic algorithm based on matrix coding. The selection, crossover, mutation arithmetic operators are defined, and also all arithmetic operators’ Matlab function are compiled. It proves the practicability of the new algorithm by simulating a two matrix variables function optimization. Results show that the new genetic algorithm can ensure the configuration integrality of the matrix chromosome, and increase the operation speed and optimization precision.
  • LI Chi-Chen, LUO Bin-Jian, ZHI Yang-Jian, ZHANG Yu-Lin
    Computer Engineering. 2011, 37(13): 163-165. https://doi.org/10.3969/j.issn.1000-3428.2011.13.052
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    Aiming the problem of chaos Support Vector Machine(SVM) regression model has low efficiency traffic prediction, Differential Evolution(DE) algorithm, Genetic Algorithm(GA) and Particle Swarm Optimization(PSO) algorithm are applied for determining the model’s parameters which includes radial basis kernel function coefficient, punishment coefficient, insensitive coefficient, and builds the improved chaos SVM model to predict traffic. Example show that DE algorithm can significantly reduce the time for determining the model compared to another heuristic algorithms, and the model has higher prediction accuracy.
  • SUN Dao, LIU Yong, FENG Lin
    Computer Engineering. 2011, 37(13): 166-168,171. https://doi.org/10.3969/j.issn.1000-3428.2011.13.053
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    To reduce computation and time of the traditional gait plan method, this paper presents a stable gait planning method based on key frame similarity algorithm of humanoid robot. Through measure similarity of the gait key frame, planning the hip movement, adjusting robot’s Zero Moment Point(ZMP), it implements on-line gait generation of curve walking and the adjustment gait can better approximation actual ZMP curve. Practice result shows that this method can solve the gait of a humanoid robot stable and rapid planning at the same time in reducing computation, and it can reduce time consumption when gait selection is not ideal.
  • LIU Shuang-Yi, XU Long-Qin
    Computer Engineering. 2011, 37(13): 169-171. https://doi.org/10.3969/j.issn.1000-3428.2011.13.054
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    Multi-influence factor effect on the attribute weight and the relatedness of its attributes is rarely considered in traditional case searching algorithm. Therefore, this paper proposes an improved case similarity algorithm combined the improved covering algorithm and the grey relational degree to optimize case retrieval. Proposed algorithm obtains the best retrieval case by using the improved grey relational degree case retrieval algorithm whose case attribute weight is figured out by auto-adapted algorithm based on the multi-influence factor. Compared with many other kinds of case searching algorithms, experimental results indicate that proposed algorithm can overcome the disadvantage of the traditional case retrieval algorithm and enhance the quality and the efficiency of the case retrieval effectively.
  • JIANG Guo-Rui, TUN Lin
    Computer Engineering. 2011, 37(13): 172-174,177. https://doi.org/10.3969/j.issn.1000-3428.2011.13.055
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    In the opponent selection process of Multi-Agent-based negotiation, this paper uses the gray theory to deal with the fuzzy interval attributes of negotiation opponents under uncertainty information condition. It gets the gray interval value information from knowledge base and constructs a two-factor model of relationship and profit, calculates the ideal opponent evaluation vector, sets the bleaching weight function, analyzes multi-attribute gray cluster of negotiation opponents, and gives a specific example for illustration. This method perfects the opponent selection method under uncertain information, and improves the environmental adaptability of negotiations.
  • DENG Hui, WANG Yong, CHEN Shi-Liang
    Computer Engineering. 2011, 37(13): 175-177. https://doi.org/10.3969/j.issn.1000-3428.2011.13.056
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    In the light of the deficiencies of Population Migration Algorithm(PMA), such as slow convergence speed, easily to fall into local optimum, the low solution precision and so on, this paper takes pattern search method as a local optimization operator and embeds it into PMA, that is to say, every point which is randomly generated by PMA is locally optimized by pattern search, and proposes an optimization approach named HJPMA which combines pattern search with PMA. The simulation results show the proposed algorithm has faster convergence speed, higher computational accuracy, and is quite effective for solving global optimization problems.
  • YUAN Ge-Gong, LI Yan-Xiao, GUO Hai-Xiang, CHU Ke-Jun
    Computer Engineering. 2011, 37(13): 178-180. https://doi.org/10.3969/j.issn.1000-3428.2011.13.057
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    Aiming to the complexity and uncertainty of oil-bearing of reservoir recognition, this paper proposes an improved ant colony clustering algorithm. It sets the category of reservoir as a variable, uses Jaccard index to measure the coincidence between clustering result and the given conclusion. The clustering compactness is evaluated by the virtue of the variance between the samples and the center in a cluster, and the optimal partition is achieved by means of the improved ant colony clustering algorithm. Experimental result indicates that the coincidence between the clustering result and the given logging interpretation is high and so is the coincidence in all clusters, so that the algorithm has preferable predictability and inspection capability.
  • SONG Dan
    Computer Engineering. 2011, 37(13): 181-182,186. https://doi.org/10.3969/j.issn.1000-3428.2011.13.058
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    This paper proposes a Memory Evolutionary Algorithm Based on Adaptive Selecting Dimension(MEABASD). It sets a three- dimensional array to save useful evolutionary information in order to guide the evolution of the follow-up, which can enhance the local search ability. In mutation process, combining with memory information, it adaptively selects the dimension to mutation to strengthen the effectiveness of mutation. The best contemporary populations does self-learning operator to improve the precision of the algorithm. Simulation results on standard test functions show that the algorithm is suitable for the high-dimension optimization problem, and it has the characteristics of rapid convergence, powerful global search capability and high stability.
  • ZHONG Jiang, LIU Long-Hai, LIANG Chuan-Wei
    Computer Engineering. 2011, 37(13): 183-186. https://doi.org/10.3969/j.issn.1000-3428.2011.13.059
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    An active method which can effectively select pairwise constraints is constructed. By using this method, an active semi-supervised text clustering method based on pairwise constraints is proposed. Latent Semantic Index(LSI) is used to reduce the dimension of text features. In the clustering process, it uses the proposed method to actively select pairwise constraints, and then uses these pairwise constraints to steer the clustering process towards an appropriate partition. Experimental results show that the proposed method can effectively improve the text clustering results by using a small amount of pairwise constraints.
  • WANG E-Song, GUO Hua-Beng, FAN Meng
    Computer Engineering. 2011, 37(13): 187-189,192. https://doi.org/10.3969/j.issn.1000-3428.2011.13.060
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    Based on existing ensemble pruning methods, this paper presents a beam search-based combination pruning method from the view of expanding the search. The method adopts beam search method, and saves the first k optimal combinations while adding or removing a search-based ensemble in each step. That not only remains the characteristics of efficiently pruning of the original combination pruning methods in greedy way, but also reduces the risk that fast convergence leads to local optimum easily, makes combination classification after pruned closer to the global optimum. Comparison results show that this method has a higher accuracy of classification, and it is smaller than the original ensemble pruning methods on most datasets.
  • XU Chun-Meng
    Computer Engineering. 2011, 37(13): 190-192. https://doi.org/10.3969/j.issn.1000-3428.2011.13.061
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    Locality Sensitive Discriminant Analysis(LSDA) is a recent proposed supervised feature extraction algorithm. LSDA can not only utilize the class information but also consider the the intrinsic geometrical structure of the data. However, LSDA is a vector based method so it neglecteds the spatial correlation of the pixels in the image, and its performance may be degraded in this case. To solve the problem, this paper proposes a Smooth LSDA (S-LSDA) method. It introduces a spatially smooth regularization which incorporates the spatial correlation information into the objective function of LSDA. It shows that the derived coefficients are spatially smooth and the extracted features are more effective for classification. Experimental results on face image databases show the effectiveness of the proposed algorithm.
  • DAN Yun, SUN Chong, FANG Feng
    Computer Engineering. 2011, 37(13): 193-195. https://doi.org/10.3969/j.issn.1000-3428.2011.13.062
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    When using the traditional Dijkstra algorithm for path guiding, the problems of large base number of road net node, wide searching range. With these drawbacks, much time and space are consumed. So the efficiency and real-time quality of Parking Guide Information System(PGIS) are both reduced. To solve these problems, in the light of the specific environment of city road net and the requirements of path guiding, according to the basic principle, straight line makes the shortest distance between two points, this paper puts forward a rectangular searching range based, improved Dijkstra algorithm which is applicable to PGIS. This paper designs and implements the solutions of such problems as one-way road, no passing road and cross point time delay in city road network model. Experimental results show that the improved Dijkstra algorithm not only can reduce the searching range of road net nodes and computational complexity, but also can improve the real-time quality when users searching for the path.
  • ZHANG Yong, JI Dong-Sheng
    Computer Engineering. 2011, 37(13): 196-198,201. https://doi.org/10.3969/j.issn.1000-3428.2011.13.063
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    Existing Harris feature point detection algorithm uses Gaussian smoothing filter, but it has a phenomena that image feature points extracted angular point information is of lost and migration. In order to solve the problem, the data-fitting and low-pass characteristics of B-spline function are introduced into the algorithm to construct a new filter, while the morphological filter is also introduced into the maximum inhibition of ideal that using fast moving window search algorithm for extracting feature points to improve the precision and speed of features point extraction. Experimental result shows that the improved algorithm detected feature points is rapid, uniform and accurate, and it has good noise suppression.
  • LIU Jing-Bei, LUO Wei-Min, LIU Jing
    Computer Engineering. 2011, 37(13): 199-201. https://doi.org/10.3969/j.issn.1000-3428.2011.13.064
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    For the problems of the instable training results and low rate of pattern recognition in Self-Organizing Mapping(SOM), a novel Repulsive Equilibrium SOM(RESOM) is proposed in this paper. Theory of repulsive force is used in this method, pattern recognition based on the cluster regions of SOM, these regions move to repulsive equilibrium position in repulsion field. Experimental results show that RESOM method outperforms the normal SOM and SVM. It can improve stability and recognition rate of pattern recognition and reduce training time.
  • LIU Jun, WANG Su-Mei, HE Guo-Guo, YUE Xin-Lian
    Computer Engineering. 2011, 37(13): 202-204. https://doi.org/10.3969/j.issn.1000-3428.2011.13.065
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    Aiming at the on-line prediction problem of vehicle attitude angles, this paper uses 6 degree of freedom vehicle motion parameters to measure directly by Micro Inertial Measurement Unit(MIMU) in strap-down way, then quaternion is adopted for attitude algorithm and Kalman filter is used to get the optimal estimation of attitude angles. Auto-regressive(AR) model is set up for future 1 s~3 s prediction of attitude angle. In addition, on-line prediction software for vehicle attitude angles is developed based on Visual Basic 2005 and NI measurement studio, and the road test is carried out. The result shows the validity and feasibility of on-line prediction software for vehicle attitude angles.
  • YANG Chao, GUAN Yi-Hong, GUO Bin, YUAN Hong-Pan
    Computer Engineering. 2011, 37(13): 205-207. https://doi.org/10.3969/j.issn.1000-3428.2011.13.066
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    This paper proposes an image segmentation algorithm, which combines Markov Random Field(MRF), two-dimensional histogram of fuzzy clustering and Dempster-Shafer theory. The algorithm uses simulated annealing to restore the contour of the brain, and the nuclear part of the brain is extracted from the original image according to the profile, then the brain nuclear image is divided by MRF and two-dimensional histogram of fuzzy clustering. However, two ways above lead to different classification results while the controversial pixels are classified, so it makes use of the Dempster-Shafer evidence theory to assign the controversial points to the plausibility interval and divide them. Experimental results show that the proposed algorithm is robust, which can solve the problem that the class attribution of the controversial points and suppress the noise effectively.
  • CHEN Jian-Jun, TIAN Feng-Chun, LI Can
    Computer Engineering. 2011, 37(13): 208-209,212. https://doi.org/10.3969/j.issn.1000-3428.2011.13.067
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    A blind restoration algorithm of P-Laplace diffusion based on anisotropic and nonlinear regularizations is proposed for restoring degraded images, in which the anisotropic and adaptive regularizations are adopted according to the character of image curvature and gradient. The nonlinear and spatial anisotropic regularization functions are suggested to smooth adaptively in the process of recovering the object image. The cost functions are minimized by alternate minimization scheme. The nonlinear equations are linear by fixed-point iteration scheme. The images can be recovered quickly. Experimental results show that the algorithm can restore image and improve image quality effectively.
  • BO Yu, SUN Quan-Sen, JIA De-Shen
    Computer Engineering. 2011, 37(13): 210-212. https://doi.org/10.3969/j.issn.1000-3428.2011.13.068
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    This paper proposes an image fusion framework based on Principal Component Analysis(PCA) decomposition. PCA is applied to the source images; then approximate images are acquired after subsampling the image reconstructed with the first few components; the differences between current approximate image and the last approximate image construct the detail image; the last approximate image and all of the detail images are merged into a new fused image. Experimental results demonstrate that this framework is able to get good performances in image fusion by keeping more details.
  • DING Sheng-Rong, MA Miao
    Computer Engineering. 2011, 37(13): 213-215,218. https://doi.org/10.3969/j.issn.1000-3428.2011.13.069
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    Focusing on a kind of familiar noise, i.e. speckle noise, this paper presents a simple and efficient method on blind parameter estimation of speckle noise in an image. In the method, after various intensity speckle noise are added into a simulation image respectively, the regularities of histogram distribution in unitary grey area are analyzed. On the basis of the regularities of distribution, noise characteristic value standing for noise intensity is constructed. A function map between noise parameters and noise characteristic values are deduced out. Experimental results indicate that the function map can estimate the noise intensity in noise-polluted images rapidly and efficiently without any prior knowledge. Potential applications includes noise circumstance assessment in cases of image acquisition or transmission, analysis on relationship between noise intensity and image quality, assistance on the improvement of current noise suppression algorithms, etc.
  • LIN E-Zhong, GU Jin-Ku, HAO Gang-
    Computer Engineering. 2011, 37(13): 216-218. https://doi.org/10.3969/j.issn.1000-3428.2011.13.070
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    In intensity inhomogeneity image segmentation, the Adaptive Distance Preserving Level Set Evolution(ADPLS) algorithm can get a result with high speed, low accuracy and has no relation to initial contour, on the other hand, the Local Binary Fitting(LBF) algorithm can get a result with high accuracy, low speed and its result is sensitive to initial contour. Thus, a novel and adaptive fusing level set method is proposed to make use their advantages respectively, which can automatically adjust the proportion of ADPLS and LBF in the fusing method according to image information. Experiment results show that the comprehensive performance indicators, such as accuracy, speed and stability can be significantly improved in the fusing method.
  • HAN Jing-Song, GU Zhen-Gong, TU Yin-Feng, YANG Jie, LONG Shao-Ning
    Computer Engineering. 2011, 37(13): 219-220,226. https://doi.org/10.3969/j.issn.1000-3428.2011.13.071
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    In order to reduce the computation of the minimum interclass variance algorithm in the remote sensing image segmentation, the equivalent of the objective functions is proved based on the principles of the minimum variance algorithm and the k-means clustering algorithm. In addition, a new fast minimum variance algorithm based on the k-means optimization is proposed. Experimental results show that it effectively reduces the hunting zone and has a real-time speed to calculate the optimal threshold.

  • GU Feng, SUN Jun, ZHOU Jun
    Computer Engineering. 2011, 37(13): 221-223. https://doi.org/10.3969/j.issn.1000-3428.2011.13.072
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    The rate jitter of different views of stereo video becomes much larger after separated depending on the classification of views. An adaptive double-buffered rate smoothing method is proposed to solve this problem. According to the peculiarity of rate jitter, the method applies two-stage rate smoothing policy on each view at the server side. The stream of one view is stored into a buffer and then sent to second stage according to the frame rate at first stage. At second stage, stream receives from first stage and then sends out according to the buffer occupancy rate. Experimental results validate the method can effectively deal with rate jitter.
  • LIU Xue-Dong, LI Qiang, MAO Rui-Xue
    Computer Engineering. 2011, 37(13): 224-226. https://doi.org/10.3969/j.issn.1000-3428.2011.13.073
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    An object-based coding algorithm is proposed for surveillance video compression. Subjective visual quality instead of the traditional PSNR is adopted as the evaluation criterion of reconstructed image so as to fulfill the specific purpose of surveillance video. The surveillance region is enhanced in a controllable manner to improve visual effect, and then lossless compression is conduced. Experimental results show that better subjective quality of surveillance objects region and higher coding efficiency are achieved at the cost of low complexity by the proposed algorithm.
  • ZHOU Xiang-Sheng, TIAN Feng-Chun, SONG Jian-Wen, DUAN Chu-Yu
    Computer Engineering. 2011, 37(13): 227-228,232. https://doi.org/10.3969/j.issn.1000-3428.2011.13.074
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    Based on motionlessness detection and motion vector prediction, an effective motion estimation algorithm combining local full search and down-sampling is proposed. It accelerates the search speed and maintains high search accuracy. The motion estimation algorithm is applied to the Frame Rate Up-conversion(FRUC) system. Experimental results show that the proposed algorithm not only reduces the calculation complexity, but also maintains satisfactory visual quality and PSNR.
  • LIU He-Hua
    Computer Engineering. 2011, 37(13): 229-232. https://doi.org/10.3969/j.issn.1000-3428.2011.13.075
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    Aiming at different bandwidth users live streaming media server for audio quality/video quality of the demand, this paper designs and implements a network broadcast platform based on Linux. It uses MPEG4IP to realize MPEG4 encoding software; uses Real-time Transport Protocol(RTP) protocol to transfer data way to achieve the client broadcast the request. SDL library by calling the method is implemented in the Linux platform to display the video playback. Experimental results show that this platform transmission works well, system stability and load balance have a good performance.
  • DUAN Chu-Yu, TIAN Feng-Chun, ZHOU Xiang-Sheng, SONG Jian-Wen
    Computer Engineering. 2011, 37(13): 233-234,237. https://doi.org/10.3969/j.issn.1000-3428.2011.13.076
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    Based on the classic Three Step Search(TSS) algorithm, a more efficient motion estimation method, Double Tracing Three Step algorithm (DTTSS) is proposed. After the first step, DTTSS selects two best match points as start points in the next step for double tracking. With relatively high search speed, DTTSS can avoid the local optimum problem in the TSS. This algorithm is compared with Full Search(FS), Local Full Search(LFS), Three Step Search(TSS) in Motion Estimation and Motion Compensation(ME/MC) frame rate up conversion system. Experimental results show the effectiveness in the average number of search points of each block, the accuracy, the visual effect of the interpolated frame and its PSNR.
  • DIAO Lin, FENG Yan, GU Ying-Biao
    Computer Engineering. 2011, 37(13): 235-237. https://doi.org/10.3969/j.issn.1000-3428.2011.13.077
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    Aiming at the problem of background occlusion existed in traditional video tracking method, a novel particle filtering tracking method based on derivative optical flow is proposed. In this method, a derivative optical flow model used for describing the object is built, and the model is updated ahead of tracking in every frame. The similarity between the object and the particle is measured by the optical flow similarity function, then the tracking is accomplished by the estimate of particle filtering. Experimental results show that the method can correctly track the object occluded by background, no matter whether the gray intensity of the object and background is similar or different.
  • YANG Tong-Jie, DAI Zi-Ban, YANG Xiao-Hui
    Computer Engineering. 2011, 37(13): 238-240. https://doi.org/10.3969/j.issn.1000-3428.2011.13.078
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    This paper presents an improved Residue Number System(RSN) Montgomery modular multiplication algorithm, which is optimized by pre-computing the constant parameter. Compared to the Bajard J C(IEEE Transactions on Computers, 2004, No.6) algorithm, the number of modular multiplication is reduced by 300/(2k+8) percent. A hardware design of scalable modular multiplier is proposed, which is implemented on 0.18 μm SMIC process. Result shows that the design has advanced performance.
  • BIAN Dun, HUANG Wen-Jun, HE Wei-Ting
    Computer Engineering. 2011, 37(13): 241-242,245. https://doi.org/10.3969/j.issn.1000-3428.2011.13.079
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    Aiming at the functional safe demands of programmable electronic systems in IEC61508, this paper proposes the safe design of Analog Input(AI) module based on ARM Microprocessor. It expounds the technique of diagnosis and implementation in this module. This design has two separated ARM microprocessors used for work and diagnosis, and has high diagnostic coverage, it conforms to the requirements of IEC61508, it is suitable for SIL3/SIL4 security system.
  • MA Feng, FANG Xiao-Min, WANG Chun-Jun, HU Qiu-Hui
    Computer Engineering. 2011, 37(13): 243-245. https://doi.org/10.3969/j.issn.1000-3428.2011.13.080
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    This paper designs a compound branch predictor circuit based on the current branch predictor algorithms, whose application is limited in the precise prediction of a certain kind of program. This circuit, combining branch prediction of many different types, can predict various programs with high precision, and is accordingly applied in the independent innovation and embedded computer design. Results indicate that the branch predictor circuit realizes the precision demand and other requirements of the computer design.
  • LI Feng, MA Gong-Mei, ZHANG Xu-Zhen
    Computer Engineering. 2011, 37(13): 246-247,261. https://doi.org/10.3969/j.issn.1000-3428.2011.13.081
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    As for the problem of the filter’s bandwidth imprecision and stop-band attenuation too small, a passive analog filter optimization design method is proposed based on the Particle Swarm Optimization(PSO) algorithm. The filter is designed by the network synthesis design method, and it optimizes the circuit’s parameters in the whole parameters space effectively and globally by PSO until gain the best parameters. This method can improve the filter’s bandwidth imprecision and the high stop-band suppression.
  • WANG Ti-Pu, CHEN Ai
    Computer Engineering. 2011, 37(13): 248-250,264. https://doi.org/10.3969/j.issn.1000-3428.2011.13.082
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    The target of implementation of traditional gap is to isolate two different network environment, it does not support high concurrent applications and high speed connectivity. To propose a software method of extending gap device, this paper designs a forward adapter and a backward adapter based on pool strategy around the device, they can be set as a buffer and connection-optimized accessories, it is designed to manage the resource of connecting and disconnecting of backward adapter and forward adapter with security gap, creating and destroying of threading. Therefore, it can reduce the dispatch load, isolate high concurrent connection of networking. Experimental results show that the method is feasible and effective, it can greatly makes up for the shortcoming and deficiencies of high concurrent connection.
  • XIE Ban, DIAO Li-Ye
    Computer Engineering. 2011, 37(13): 251-253,268. https://doi.org/10.3969/j.issn.1000-3428.2011.13.083
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    For each tool in embedded software Integrated Development Environment(IDE) integration, communication and functional interaction requirements, this paper proposes a mechanism based on asynchronous communication software bus communication framework, discusses its design and implementation principle, and analyzes operating mechanism of its core function. With remote debugging, dynamic loading and unloading, system diagnostic and other tools in IDE, it presents application examples of the software bus. Result shows that the software bus can be used to efficiently design and integration embedded software development tools.
  • XIE Beng, LI Shu-Yu
    Computer Engineering. 2011, 37(13): 254-256,271. https://doi.org/10.3969/j.issn.1000-3428.2011.13.084
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    Aiming at the configuration problems of single MPU and ASIC in embedded system, this paper proposes an improved Particle Swarm Optimization(PSO) which is applied to HardWare/SoftWare(HW/SW) partitioning of digital audio/video decoder, each run of the algorithm can produce many Pareto-optional solutions, and the problems of target function, system constraint, Particle comparison criterion, congestion distance function, mutate operator and particle Fitness are discussed. Experimental result shows that the algorithm improves immature convergence, less Pareto-optimal solutions and Front-end distributed heterogeneous of Pareto-optimal solutions of traditional algorithm, strengthens adaptability and global optimality of results.
  • LIU Jia-Jia, HE Jia-Long, TUN Shun-Xiang
    Computer Engineering. 2011, 37(13): 257-258. https://doi.org/10.3969/j.issn.1000-3428.2011.13.085
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    In Internet era, a lot of criminals usually carry out Internet fraud and other criminal activities, using instant messaging software as a medium. This paper takes Aliwangwang as an example, and researches into Aliwangwang’s information storage structures as well as its data encryption algorithm of RC4 and MD5, proposing a distributed computing model based on CUDA to brute force the data encryption algorithm of RC4 and MD5 by exhausting all possible secret keys. The results show this model can get the right encryption key of Aliwangwang’s encrypted file quickly. This research is very useful for computer investigation and forensics in practical use.
  • YANG Peng, LV Yin, HUANG Jin-Cheng
    Computer Engineering. 2011, 37(13): 259-261. https://doi.org/10.3969/j.issn.1000-3428.2011.13.086
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    According to the features of wireless network data, this paper puts forward a data complement algorithm based on fuzzy clustering. This algorithm takes data periodicity into consideration and uses deposit history data to complete missing data, clusters the deposit data to make several standard templates and uses the templates to fill in missing data. This algorithm is applied to fill in cellular hour traffic. Experimental results show that it has a small average error rate and good unbiasedness, it can still complete data under severe missing circumstance.
  • LI Jia, TUN Yi-Reng
    Computer Engineering. 2011, 37(13): 262-264. https://doi.org/10.3969/j.issn.1000-3428.2011.13.087
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    This paper proposes a scheme to construct digital community based on the Internet of Things(IOT) to meet the need of the practical application. The scheme concludes technical framework improvements of the IoT for application, discussion of the networking mechanisms, implementations of technical details and design of network nodes. It presents a multi-frequency-multi-structure network architecture. Test results of typical application parameters show that the practical application of the scheme in digital community is feasible.
  • TU Hua-Chao, KONG Xue, WANG Xu, CHU Yong-Xin, HE Wei-Feng, NI Meng, XIE Guang-Wei, LEI Yong-Mei, CHAN Jian-Chen
    Computer Engineering. 2011, 37(13): 265-268. https://doi.org/10.3969/j.issn.1000-3428.2011.13.088
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    This paper applies Fast Multipole Method(FMM) to Nbody application, analyzes and implements major computing tasks on CPU and Digital Signal Processor(DSP) separately. It proposes the reconfigurable ASIC contained multicore DSP construction model based FMM. Taking Field Programmable Gate Array(FPGA) for example, it evaluates the better energy efficiency when revolved in floating point applications on the model.
  • LI Lian-Chun, ZHOU Jin-Chi
    Computer Engineering. 2011, 37(13): 269-271. https://doi.org/10.3969/j.issn.1000-3428.2011.13.089
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    In allusion to the problems of describing and managing massive network data, this paper presents a semantic information extraction system for audio/video. According to the characteristics of network audio/video streams, it formulates protocol identification rules using regular expression. On this basis, multilayer semantic information from network interface layer, network layer, transport layer and application layer is extracted by analyzing the structure of audio/video transmission protocol. Meanwhile a Uniform Content Locator(UCL) label is constituted. Experimental results show that the proposed algorithm has recall and accuracy both over 80% under the requirement of complete flows.
  • XIAO Lin, LIANG Jun, CHOU Wen-Liang
    Computer Engineering. 2011, 37(13): 272-274,278. https://doi.org/10.3969/j.issn.1000-3428.2011.13.090
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    A precise bitmap index named FPT-Index is proposed to solve the problem that the query results are not precise in approximate bitmap index base on bloom filter. FPT-Index uses bloom filter to compress the basic bitmap index and introduces false positive table to screen the query results. The query results from FPT-Index are precise. Through theoretical analysis, the minimum of compression ratio and the corresponding number of hash functions can be worked out when the keyword frequency is confirmed. Experimental results show that FPT-Index does better in compression ratio and search performance than WAH.
  • TONG Qiang, ZHANG Jing-Yi, CHEN Cheng, DING Xie, HONG Ke-Hao
    Computer Engineering. 2011, 37(13): 275-278. https://doi.org/10.3969/j.issn.1000-3428.2011.13.091
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    This paper makes a research on the achievable technology of structural plan and visual plan. Rule Based Reasoning(RBR) and Case Based Reasoning(CBR) methodology are applied to the achievable technology for intellectual inference and analysis, so that depending on and targeting for certain emergency information an intellectual emergency plan can be automatically produced. It designs and implements the emergency command system based on structural and visual plan. It is capable of meeting the demand of producing an intellectual emergency plan quickly and accurately in the emergency command, which increases the pertinency and effectiveness of the plan in the whole process of emergency disposition.
  • PENG Ning, XU Hong-Yi, YANG Ke
    Computer Engineering. 2011, 37(13): 279-281,284. https://doi.org/10.3969/j.issn.1000-3428.2011.13.092
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    A method of Symbol Error Ratio(SER) computation for cross Quadrature Amplitude Modulation(QAM) signals is given. The constellation is divided into different regions based on decision boundaries according to the characteristics of cross QAM. The general theoretical bounds of SER for the cross QAM signals over Additive White Gaussian Noise(AWGN) channel and Rayleigh fading channel are given. Analysis and simulation results demonstrate that the theoretical bound offers an accurate criterion for SER of cross QAM.
  • SHU Ji-Bei, KONG Xue, ZHENG Zhe, CHU Yong-Xin, FU Yu-Zhuo
    Computer Engineering. 2011, 37(13): 282-284. https://doi.org/10.3969/j.issn.1000-3428.2011.13.093
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    This paper introduces the development of Field Programmable Gate Array(FPGA), and evaluates the usability of FPGA devices which include the use of reconfigurable logic, Block RAM(BRAM), I/O resources, Digital Signal Processor(DSP) hard core, the selection of CPU soft core/hard core and the usable clock frequencies. It predicts future trend in the ever quest for high performance FPGA. It suggests not using slice resource more than 85%, selecting better supported tool company for soft/hard core and let all I/O signal buffered by registers.
  • WANG Xue-Lin, CHEN Yan-Qiu
    Computer Engineering. 2011, 37(13): 285-287,290. https://doi.org/10.3969/j.issn.1000-3428.2011.13.094
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    In order to detect whether color printing registration image exists deviation and deviation parameter, this paper presents a detection algorithm of color printing deviation based on Edge Co-occurrence conditional probability Matrix(ECM). It detects the edge information of color printing registration image, calculates ECM of edge image, and extracts the peak value of ECM. If peak value exists except (0,0) point, the color printing registration image exists deviation and the peak value is the deviation parameter; otherwise, the color printing registration image does not exist deviation. Experiments demonstrate that the detection result can accurate to one pixel, and the algorithm is effective and accurate.
  • LUO Men-Feng, LUO Jia-Xiang
    Computer Engineering. 2011, 37(13): 288-290. https://doi.org/10.3969/j.issn.1000-3428.2011.13.095
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    This paper focuses on Printed Circuit Board(PCB) and their components arrangement optimization problem, which includes two tasks: the sequencing of PCB and the assignment of components on PCB to different mounting machines. A taboo search with kick strategy is proposed to solve the problem that ordinal optimization is applied to obtain a favorable initial solution. It compensates for the dependence on the initial solution of taboo search and contributes to obtain a better result in a large possibility. Kick strategy is embedded into taboo search, and the global search ability of the algorithm is greatly strengthened. Experimental result shows that the algorithm is effective for solving the PCB and their components arrangement optimization problem.
  • CHENG Yi-Wei
    Computer Engineering. 2011, 37(13): 291-292. https://doi.org/10.3969/j.issn.1000-3428.2011.13.096
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    At present, most of the virtual experimental platform lack support for heterogeneous components. To solve this problem, this paper presents the virtual experimental platform of a new idea. As known, Web service has some advantages such as language independence and platform independence. This platform can use this technology to convert a heterogeneous component to a Web service component. In this way, this platform realizes the communication of heterogeneous components and improves the efficiency of development and achieves the component reuse. It introduces the architecture model of the platform and the key technology of the system realization, and then discusses how to convert a heterogeneous component to a Web service component, and also discusses the design and implementation for the experiment execution engine. It takes this platform as the foundation and uses Web service technology, some C++ and Matlab components are integrated into this platform to achieve a digital image processing virtual lab.