20 October 2011, Volume 37 Issue 20
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Computer Engineering. 2011, 37(20): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2011.20.001Aiming at the identity recognition problem for pedestrian in night, combined with gait outline character and model projection character, a hybrid feature combining the shape information obtained by Radon transform and the walking style information obtained by human tracking is presented. The 3D model tracking method is given. Experimental results show the method is robust for occlusion and human condition changing. SVM is used for classification. The recognition rate can be 95.28%.
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Computer Engineering. 2011, 37(20): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2011.20.002This paper studies the reconfiguration method of Enterprise Information Systems(EIS) based on Object-based Knowledge Mesh(OKM) and approximate matching. According to the approximation of models, reconfiguration elements, the matching degree of knowledge point and relationship element are defined. Based on the operations of OKM and Information Transfer Relationship Mesh(ITRM), the reconfiguration algorithms is proposed. Rules in the reconfiguration are explored. Examples proves the validity of the reconfiguration method.
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Computer Engineering. 2011, 37(20): 7-9. https://doi.org/10.3969/j.issn.1000-3428.2011.20.003The demanding sample rate of classical Turn-on Radio Frequency Fingerprints(RFF) is very high and their receiver structure is quite complex. This paper proposes a novel RFF based on frame synchronization code whose separability is enhanced. The foundation of RFF and typical RFF identification system model are introduced. Based on the derived relation formulation among separability and influencing factors of RFF, the novel synchronization code RFF transform method is proposed. Experiences with IEEE 802.11 wireless interface cards demonstrate that the proposed RFF overcomes the shortcoming of classical Turn-on RFF.
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Computer Engineering. 2011, 37(20): 10-12. https://doi.org/10.3969/j.issn.1000-3428.2011.20.004According to the problem of grain emergency scheduling, establishing a multi-objective optimization model for multi-emergency point and multi-rescue point, which treat the earliest start time of emergency and the least number of rescue point as optimization target. To consider the urgent importance of each emergency point and the characteristics of nonconstant grain continuous consumption, corresponding factors are introduced. Using ant colony algorithm to solve and giving out the steps for solving as well, an example verifies that the model can improve the efficiency of grain emergency scheduling.
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Computer Engineering. 2011, 37(20): 13-15. https://doi.org/10.3969/j.issn.1000-3428.2011.20.005For mobile user group, this paper formulates a method based on the distribution of the mobile users. It calculates the population densities by the statistics of the mobile users. It finds the peak and characteristic radius of each Gaussian distribution according the multi-peaks Gaussian distribution model and densities. The peak and characteristic radius are the centre and radius of the group respectively. It gets all the groups. This method can group users reasonably, and control the center and the scale of the groups easily.
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Computer Engineering. 2011, 37(20): 16-17. https://doi.org/10.3969/j.issn.1000-3428.2011.20.006This paper studies the independent micro-assembly method based on visual servo. In order to realize the depth information estimation, it presents a blur parameter model of defocus image based on Markov random field for performing an effective and reliable automatic micro- assembly, which converts the problem of depth estimation into optimization problem. An improved Broyden method for estimating the image Jacobian matrix online is presented as the visual servo method. It designs the experiment of microgripper fix position and clip. Experimental results confirm that the proposed methods are effective.
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Computer Engineering. 2011, 37(20): 18-20. https://doi.org/10.3969/j.issn.1000-3428.2011.20.007To resolve the problems of high computation and low robustness of existing affine invariant feature extraction methods, a new affine invariant region extraction method based on connected region is proposed. The input gray image is filtered with an anisotropic gauss filter and then histogram equalization is performed. Connected regions with the same pixel values are found. Adjacent connected regions whose gray values’ difference is less than delta are merged. The ultimate merging result that satisfies the demand is concerned as the image’s local affine invariant regions. Experiments show that this method is very effective, fast and highly robust.
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Computer Engineering. 2011, 37(20): 21-23. https://doi.org/10.3969/j.issn.1000-3428.2011.20.008Distributed systems have multi-configuration items and system integration test is more complex, so this paper proposes a system collaboration test scheme for distributed application. It puts forwards the analysis of the application scene, the generation of test script files, and the realization of distributed system collaboration test which uses functional test, interface test and performance test. Fault detection and quality assessment of distributed systems are carried out. Practice proves that the scheme has an actual effectiveness on increasing the efficiency and saving the test costs.
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Computer Engineering. 2011, 37(20): 24-26. https://doi.org/10.3969/j.issn.1000-3428.2011.20.009This paper analyzes memory layout, management strategy and protection mechanism of Cisco Internetwork Operating System(IOS), and does some memory management vulnerability tests. Based on the results, it analyzes the vulnerability on memory management strategy and memory protection mechanism, which proves that there are some security risks on IOS memory management. Several effective approaches are proposed to improve the security of Cisco router, such as adding validation and integrity protection.
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Computer Engineering. 2011, 37(20): 27-29. https://doi.org/10.3969/j.issn.1000-3428.2011.20.010In order to resolve the problem of traditional Apriori algorithm that exists redundancy subgraphs when mining frequent subgraph, a new frequent subgraph mining algorithm called GAI is proposed. To reduce the number of scanning database, MADI index structure of three levels is proposed to store the information of graphs. It uses the expansion of the ETree to construct the frequent graph, and uses tables to store candidate subgraphs. It is avoided the redundancy subgraphs in expansion processing and scanning the entire database. It greatly simplifies the calculation of support degree and improves the query efficiency of graph isomorphism and subgraph isomorphism. Experimental results show GAI has the higher mining efficiency than Apriori algorithm.
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Computer Engineering. 2011, 37(20): 30-32. https://doi.org/10.3969/j.issn.1000-3428.2011.20.011In order to improve the simplification speed of logic functions, this paper proposes an improved Q-M method for simplification of logic functions. The size of implicants set is decreased by using a pair of weights in the iteration process of comparison, only the implicants which satisfy the conditions is merged. And all prime implicants are obtained at last. Bipartite graph which is consists of prime implications and minterms is structured. The least prime implicants containing all of the minterns, that is, the minimum coverage of logic functions is obtained by heuristic approach. Experimental results show that the number of iterations can be reduced, and the speed of simplification can be accelerated.
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Computer Engineering. 2011, 37(20): 33-35. https://doi.org/10.3969/j.issn.1000-3428.2011.20.012In order to improve the semantic processing capacity of search engines, taking tourism for example, this paper proposes a model based on ontology correlation concept lattice through the way of combining domain ontology for knowledge representation and reasoning with the concept lattice theory. A new user’s retrieve items recommendation technology is designed and implemented according to the model. Experimental results show that the correlation model uses completely the instances relations and the semantic concept of ontology and the rational results are achieved..
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Computer Engineering. 2011, 37(20): 36-38. https://doi.org/10.3969/j.issn.1000-3428.2011.20.013In order to improve the precision rate of XML information retrieval, this paper proposes a feedback technique for XML information retrieval based on term expansion. It considers lexical semantic weights of nodes, adjacency frequency between lexical items and queries, and local co-occurrence between terms and keywords in computing term weight. Experimental results on Wikipedia2009 data set show that the proposed technique can improve the precision rate.
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Computer Engineering. 2011, 37(20): 39-41. https://doi.org/10.3969/j.issn.1000-3428.2011.20.014This paper studies the variable ordering of Phased Mission System(PMS) fault tree. It builds an ordering heuristic library including ten different ordering heuristics. To make the library dependable, it evaluates each single heuristic with mean performance analysis techniques based on a PMS benchmark, and evaluates the whole library with the complementarity and completeness analysis techniques. Example analysis shows that equipped with the heuristic library system Binary Decision Diagram(BDD) of large-scale PMS fault tree can be efficiently constructed.
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Computer Engineering. 2011, 37(20): 42-45. https://doi.org/10.3969/j.issn.1000-3428.2011.20.015Aiming at the problem of modeling Web-based business process, this paper models business processes using protocols based on conversations between roles that is abstracted from participants of business processes. A business protocol composition algebra is introduced and a set of composition operators are constructed. These operators include sequence, parallel, choice and iteration. Some properties of the algebra are proved. It also analyzes the similarities of protocols which lay a foundation for replacement of protocols.
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Computer Engineering. 2011, 37(20): 46-48. https://doi.org/10.3969/j.issn.1000-3428.2011.20.016In order to realize the automatic conversion of Task Model(TM) to Abstract User Interface(AUI), this paper presents a rule-based model automatic conversion method. The TM meta model of concur task tree and AUI meta model are constructed. The rule representation based on Object Constraint Language(OCL) is used to define the mapping rules from task model to abstract user interface. The eXtensible Markup Language(XML) is used to describe the task model and mapping rules. An XML file of abstract user interface is derived. An example of virtual research on job stress is given to demonstrate the feasibility and accessibility of this method.
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Computer Engineering. 2011, 37(20): 49-51. https://doi.org/10.3969/j.issn.1000-3428.2011.20.017To solve the problem that congestion influences on Quality of Service(QoS) in network, there is not a function like congestion avoidance in QoS routing algorithms now. Based on a pheromone model called Ant-Pub&Enco, Ant Colony Algorithm(ACA) is improved. The improved algorithm adopts opposite pheromone-lead mode and pheromone updating policy for different ants’ action. Based on improved ant colony algorithm, it also designs a congestion avoidance algorithm to solve QoS unicast routing problem. Simulation results demonstrate the algorithm can effectively avoid congestive link and balance the load in network.
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Computer Engineering. 2011, 37(20): 52-54. https://doi.org/10.3969/j.issn.1000-3428.2011.20.018By dividing links between nodes into forward link and reverse link, this paper presents a hybrid channel assignment strategy based on node interference in Multi-radio Multi-channel(MRMC) Wireless Mesh Network(WMN). It analyzes link interference through probability model, computes link weight between nodes, and establishes directed network connection graph with weight. The channel of fixed interface on node is assigned according to link weight, in order to decrease network interference in the process of channel switching. Simulations result of extensive NS2 shows that this method can improve the link interference and network throughput effectively.
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Computer Engineering. 2011, 37(20): 55-56. https://doi.org/10.3969/j.issn.1000-3428.2011.20.019Based on chaotic synchronization and self-adaptive observer, this paper presents a new secure communication system. By using Lorenz chaotic system and self-adaptive observer to code and decipher the original information, the objective of chaotic secure communication is realized in this system. Simulation experimental results verify that it is a simple, feasible and effective method to the synchronization of response system and drive system, and it can improve the quality and safety of chaotic secure communication.
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Computer Engineering. 2011, 37(20): 57-59. https://doi.org/10.3969/j.issn.1000-3428.2011.20.020The bounding-box algorithm realizes self-localization based on anchor nodes in communication range with simplicity and little computation. This paper presents an improved bounding-box localization algorithm in Wireless Sensor Network(WSN). Every node to be localized gets its position region by using bounding-box algorithm, then broadcasts it, after every node receives information of other nodes, they run second-localization algorithm based on information and the fact that they are among the communication range of these nodes. Simulation result shows that improved algorithm has higher localization accuracy and smaller computation.
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Computer Engineering. 2011, 37(20): 60-62. https://doi.org/10.3969/j.issn.1000-3428.2011.20.021Based on LEACH and PEGASIS algorithm, this paper proposes an assistant cluster head algorithm in Wireless Sensor Networks(WSN). It according to geographical location of the cluster head node, residual energy and the number of cluster member nodes, determines whether production assistant in the cluster head and cluster head needs to generate assistant, and chooses the right node cluster to reduce the energy consumption of cluster head communication. Assistant in PEGASIS adding cluster head, the improved assistant cluster head algorithm’s performances are improved compared to existing algorithms, in equilibrium and energy conservation, to extend the network life cycle played a positive role in terms.
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Computer Engineering. 2011, 37(20): 63-65. https://doi.org/10.3969/j.issn.1000-3428.2011.20.022This paper analyzes and compares the feature of three typical node selection mechanism of Peer to Peer(P2P) streaming media system on the media stream quality of service, network utilizing rate, network topology aggregation, etc. Aimed to resolve the problems of higher overlay-network pressure and longer service delay in current P2P streaming system, by combined topology aggregation with bandwidth priority, a two-stage algorithm of node selection is proposed. The simulation with PeerSim software shows that the performance about overlay-network pressure and media stream QoS of two-stage algorithm, which is compared to other three kinds of node selection algorithm, is significantly improved.
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Computer Engineering. 2011, 37(20): 66-68. https://doi.org/10.3969/j.issn.1000-3428.2011.20.023Based on the research of streaming communication mechanism and parameters control principle, this paper presents an point-to-point self-adaptive transmission strategy for streaming media in 3G wireless network, which includes estimation for communication link rate, principle of self-adaptive media rate control and stream track control, control of buffering feedback from clients. Analysis result shows that media server can adapt media rate and streaming track in according with network link situation and feedback parameters of clients, effectively avoid buffer underflow and overflow, achieves the purpose of using the network bandwidth resources.
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Computer Engineering. 2011, 37(20): 69-70. https://doi.org/10.3969/j.issn.1000-3428.2011.20.024Based on Lyapunov stability theory, this paper designs a linear pinning controller to achieve the synchronization of two hyper-chaos Lorenz systems. The dynamic process of synchronization is discussed by the quantitative analysis. Chaos synchronization technology is applied in secure communication. At the transmitter, the signals are modulated into parameter of the chaotic system so that the signals completely hide into hyper-chaos system, which can improve the communication security. At the receiver, a reasonable filter is constructed to demodulate communication signal. Simulation results show that the system is effective and the retrieved signal is close to source signal.
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Computer Engineering. 2011, 37(20): 71-74. https://doi.org/10.3969/j.issn.1000-3428.2011.20.025If uses cluster technology to build servers, the utilization rate of every server system resources has a great distance with each other. In order to solve the problem, this paper proposes a load balancing model based on Analytic Hierarchy Process(AHP) of Web-Server Cluster System, establishes comparison matrix, obtains individual and overall weight of every evaluation items. The scheduler receives four major categories performance parameters-network performance, server hardware, server software and network service type. Scheduler for each connection requests calculate the minimum load server by the dynamic feedback algorithm to respond to connection requests. Experimental results show that this method can reduce the average server response time, and improve the response rate of cluster system.
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Computer Engineering. 2011, 37(20): 75-77. https://doi.org/10.3969/j.issn.1000-3428.2011.20.026Aiming at the energy consumption and deploy problems in Wireless Sensor Network(WSN), this paper presents a reliable routing protocol of satisfying coverage constraint which includes coverage control and reliable data transmission features. The protocol divides the set of nodes into two parts——working nodes and redundant nodes, defines a finite state machine for them, and introduces a hybrid reliable mechanism to realize the reliability requirements as well as avoid coverage holes. Simulation result shows that protocol can extend the network life time remarkably and decrease energy consumption.
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Computer Engineering. 2011, 37(20): 78-80. https://doi.org/10.3969/j.issn.1000-3428.2011.20.027The overlay network is constructed by collecting large numbers of content servers and deploying some composition agents in every autonomy system according to the features of service composition. Since the performance of the overlay network is affected directly by the number and place of composition agents, a mathematics optimal model is built based on the comprehensive consideration of above factors and the corresponding algorithm is adopted. Simulation result shows the combination agent deployment model can make overlay network routing achieve optimal performance on the basis of meeting the combined service application requirements.
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Computer Engineering. 2011, 37(20): 81-82. https://doi.org/10.3969/j.issn.1000-3428.2011.20.028Aiming at time-frequency overlapped two-signals in single-channel, this paper proposed a method to estimate carrier frequency based on second-order cyclic cumulants. Carrier frequency estimate can be implemented by detecting the peak of the specific cycle cumulants. This method doesn’t need to separate the signals, can estimate the carrier frequency of the two-signal directly. For any combination of BPSK, QPSK, 8QAM, 16QAM modulation, simulation result shows the accuracy of carrier frequency estimation is greater than 95% when Signal to Noise Ratio(SNR) isn’t less than -5 dB.
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Computer Engineering. 2011, 37(20): 83-86. https://doi.org/10.3969/j.issn.1000-3428.2011.20.029In order to improve the reliability of the Wireless Mesh Network(WMN), in the field of Byzantine fault-tolerant computing based on the principle, this paper puts forward the concept of Byzantine unit to construct a WMN Byzantine fault-tolerant network structure. On the basis of this structure, this paper proposes a Byzantine Algorithm(BA) to improve the existing WMN routing protocol. Simulation results show that improved routing protocols can adopt the abnormal node fault-tolerant information processing, get the correct node information, remove interference and enhance the network fault tolerance, and reach the goal of raising the WMN reliability.
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Computer Engineering. 2011, 37(20): 87-88. https://doi.org/10.3969/j.issn.1000-3428.2011.20.030This paper applies the gray relation analysis theory to the ascertain of the node importance of complex network, and defines suppositional perfect “kernel node”. It takes the gray correlation degree as measure to evaluate the correlation degree of every node of the network and the perfect “kernel node”, more correlation degree more important in the network. Simulation results show the algorithm is effective, and its operation speed is fast. It can get perfect calculation capability in large-sized complex network.
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Computer Engineering. 2011, 37(20): 89-90. https://doi.org/10.3969/j.issn.1000-3428.2011.20.031Wireless Sensor Network(WSN) is prone to partitioning due to limited energy in sensor nodes and unreliable radio communications between them. Aiming at the problems of partitioned WSN, this paper uses Message Ferry(MF) based data gathering schemes, a programming problem is developed by introducing two parameters, which optimizes bits of unit time reaching the sink(network throughput). Experimental results show that network throughput does not affected by ferry speed and memory capacity of nodes, the greater speed of ferry is, the more network throughput is.
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Computer Engineering. 2011, 37(20): 91-93. https://doi.org/10.3969/j.issn.1000-3428.2011.20.032Due to the scarcity and imperfection of cognitive radio software simulation platform, this paper analyzes a simulation platform in depth, and proposes a dynamic routing algorithm for spectrum allocation based on cross-layer design, aiming to solve the deficiency of the Breadth-First Search(BFS) algorithm applied by the platform. In conclusion, through a series of simulations carried out by the updated simulation platform which adopts the new routing algorithm, it makes a better improvement in the accessing, transmission power and end-to-end throughput of the cognitive user.
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Computer Engineering. 2011, 37(20): 94-96. https://doi.org/qiqinglei1984@163.comAiming at the redundancy of Just Fast Keying(JFKi) and the absence of its forma proof, a new Lightly Just Fast Keying(LJFKi) is proposed. Through the contrast analysis, it is found that the protocol proved is one-third shorter than the natural protocol, which has higher communication efficiency and is more convenient for the sensitive network to communication payload. The proposed protocol can realize secure session ideal function and afford Universally Composable(UC) security by proving with universally composable secure model.
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Computer Engineering. 2011, 37(20): 97-99. https://doi.org/10.3969/j.issn.1000-3428.2011.20.034This paper proposes a double-routing table based defense mechanism to mitigate Eclipse attacks on P2PSIP system. Each node maintains a routing table and a reverse routing table. It periodically audits neighboring nodes to ensure compliance with the degree bound. Analysis and evaluation show that this method has promising feasibility and efficiency. In the simulation, the fraction of malicious nodes is reduced from 99% to 25%.
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Computer Engineering. 2011, 37(20): 100-102. https://doi.org/10.3969/j.issn.1000-3428.2011.20.035Researching the algorithm of Elliptic Curve Cryptosystems(ECC) and the principle of sign change fault attacks, this paper presents an improved algorithm of sign change fault attacks which can effectively solve the “zero block failure” problem and reduce the dependence of faults on private key by changing the location of induced faults. Using the improved algorithm attacks on ECC with binary scalar multiplication, simulation experiment verifies the feasibility of the algorithm.
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Computer Engineering. 2011, 37(20): 103-104. https://doi.org/10.3969/j.issn.1000-3428.2011.20.036This paper proposes a firewall-optimization method based on default-rules. This method begins by the matching probability of firewall rules, extracting some simple rules from the default-rules based on the firewall logs. After analyzing the relationship between the simple rules and the existing rules, these simple rules are emerged into the new rules. The impacts of these new rules are evaluated on the firewall and some new rules are added to the rules library selectively, to implement the optimization for the linear match of the firewall. Experimental results show that, this method can reduce the average number of rules matches, elevating the performance of firewall.
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Computer Engineering. 2011, 37(20): 105-107. https://doi.org/10.3969/j.issn.1000-3428.2011.20.037In order to increase the security of chaos-based encryption algorithm while not affecting the performance, a kind of encryption algorithm based on a two-dimensional Chebyshev maps with the combination of the m-sequence of the chaos is put forward. During the embedding of the watermark, discrete wavelet transform is done to the green luminance of RGB color space and low frequency part is extracted as the embedding field. The watermark is encrypted by using the compound chaotic sequence and is embedded into the low frequency part of the green luminance. Experimental results show that this watermark technique, in which the encrypting and embedding algorithms have less computational capacity, can resist JPEG compression, noise attack, filter and so on, as well as good digital watermark performance.
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Computer Engineering. 2011, 37(20): 108-110. https://doi.org/10.3969/j.issn.1000-3428.2011.20.038To solve Mobile IPv6(MIPv6) network communication for the general registration problem in the authentication of nodes, this paper proposes an improved and efficient authentication mechanism for the general registration. By involving the improved Identity-based Signature(IBS) signature scheme in the general registration in MIPv6, only two message interaction can complete the registration and authentication between Mobile Node(MN) and Correspondent Node(CN). In addition, shared communicating key is generated for the two sides to protect the message interaction process. Analysis result shows that the mechanism is efficient and secure.
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Computer Engineering. 2011, 37(20): 111-113. https://doi.org/10.3969/j.issn.1000-3428.2011.20.039In order to make good use of human vision redundance and obtain a higher embedding rate, on the basis of Exploiting Modification Direction(EMD), a new two-demensional steganograph scheme with high embedding rate in space domain is proposed. Dividing the cover image into m×n matrix blocks, the coded secret message is embedded in each matrix block by using EMD algorithm independently in rows and lines, and the optimal m of matrix rows equaling 1 is presented. The analysis of performance shows that the proposed method has better performance on the embedding rate than the EMD algorithm does.
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Computer Engineering. 2011, 37(20): 114-116. https://doi.org/10.3969/j.issn.1000-3428.2011.20.040Through analyzing the Session Initiation Protocol(SIP) authentication mechanism, this paper describes the vulnerability and possible attacks, such as off-line password guessing attacks and Denning-Sacco attacks. Aiming at such security problems, an improved SIP authentication scheme based on Elliptic Curve Cryptography(ECC) is proposed. Security analysis demonstrates that the improved scheme can provide mutual authentication, share the session key, guarantee the validity of authentication, effectively resist against off-line password guessing attacks and Denning-Sacco attacks.
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Computer Engineering. 2011, 37(20): 117-119. https://doi.org/10.3969/j.issn.1000-3428.2011.20.041This paper presents a dynamic multi-secret sharing scheme based on Elliptic Curves Cryptosystem(ECC). The sub-secrets of participants can update periodically. The sharing secrets and a participant can be added or deleted freely. This scheme is a multi-use verifiable secret sharing scheme, which can share several secrets in one secret sharing process. A secure channel between participants and the dealer does not need because of using signcryption algorithm on elliptic curve in the scheme. It is a secure and practical scheme.
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Computer Engineering. 2011, 37(20): 120-122. https://doi.org/10.3969/j.issn.1000-3428.2011.20.042Based on space and time-frequency, a multi-resolution gray image watermarke algorithm is proposed. For the original carrier image, it is decomposed by Discrete Wavelet Transform(DWT). For the watermarke, it is decomposed by Laplacian pyramid transformation, and is decomposed by bit-plane. After that the coefficients of the bit-plane decomposition are embedded in each layer in the horizontal and vertical components of wavelet decomposition. The chaotic Arnold mapping is utilized to generate the watermarking embedding position in order to enhance the security of watermarke. Through the inverse transformation, the embedded digital watermarke is extracted. The watermarke can be extracted without the original image. Experimental results show that the proposed algorithm is robust to some image processing operations, such as noise attacks, filtering attacks, cutting attacks, JPEG compressing attacks and rotation attacks.
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Computer Engineering. 2011, 37(20): 123-126. https://doi.org/10.3969/j.issn.1000-3428.2011.20.043Some Trojans use HTTP tunnel to pass through a variety of network security devices, which poses a serious threat to current network security. This paper presents a new method to detect the HTTP tunneling Trojans by using operation behavior characteristics. The difference between normal HTTP session and Trojan operation session with HTTP tunneling are depicted by six statistics eigenvalues, and C4.5 decision tree classification algorithm in data mining is introduced to classify the two sessions. Experimental results show that the method can efficiently detect many known HTTP tunnel Trojans.
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Computer Engineering. 2011, 37(20): 127-129. https://doi.org/10.3969/j.issn.1000-3428.2011.20.044In order to overcome the shortcomings of connectivity and resilience, which are poor in most other key pre-distribution mechanism for Wireless Sensor Network(WSN), this paper proposes a mechanism for cluster-based networks. The mechanism makes use of the distributed management strategy and can isolate the compromised sensors from the networks instantaneously through updating the coefficients of the shared-polynomial and preventing all other sensors from establishing pairwise keys with compromised sensors as a result. Experimental results show that this mechanism has good ability to resist capture and scalability. Furthermore, the updating of the key pair in time guarantees the continuing high connectivity of the networks. Besides, the communication overhead of the base station can not increase enormously when execute revocation mechanism operating.
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Computer Engineering. 2011, 37(20): 130-132. https://doi.org/10.3969/j.issn.1000-3428.2011.20.045In this paper, a video steganographic method based on motion vectors and matrix encoding is proposed to solve the problem of motion vectors modification too high. Use H.264 standard to edit video coding. A set of the motion vectors with magnitude greater than a predefined threshold are selected. And the secret messages are embed in the horizontal or vertical component of those motion vectors through the proper range of the phase angle. The matrix encoding technique is also utilized to decrease the modification rate of motion vectors. Experimental results show that this method has high supporter data utilization rate, low supporter data modification rate and computational complexity.
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Computer Engineering. 2011, 37(20): 133-135. https://doi.org/10.3969/j.issn.1000-3428.2011.20.046A cipher System on a Chip(SoC) platform is designed against the lack of applicability of current cipher SoC platform. Special-designed cipher coprocessor is integrated to realize several cryptographic algorithms and power reduction of the platform is reduced by adaptive clock gate control unit in system level. Several high and low speed communication interfaces are also supplied to complete external data exchange. Experi- mental results show that the platform can support different cipher operations effectively with lower power dissipation and higher data throughput.
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Computer Engineering. 2011, 37(20): 136-138. https://doi.org/10.3969/j.issn.1000-3428.2011.20.047An efficient way to solve the problem of information content security is to introduce Information Content Security Ontology(ICSO) into the systems and techniques. Therefore, a method of constructing ICSO is presented. The method makes full use of WordNet, extracts concepts and its relations in the information content security field from WordNet automatically, and constructs ICSO by the rules of is_a relation addition. The method is rapid and efficient, and the concepts and relations of ICSO generated by the method are more accurate. The method has the property of generality, and can construct ontology of other fields needed only by changing initial ontology.
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Computer Engineering. 2011, 37(20): 139-141. https://doi.org/10.3969/j.issn.1000-3428.2011.20.048Facing fast-spreading worms, existing detecting systems have lots of defects, such as high false alarm rate. For this reason, this paper proposes an automatic unknown worm detection technology, which uses multidimensional worm ab- normal detection method to discover unknown worms and uses salutatory multiple signatures extraction method to get the set of unknown worms’ signatures. It generates feature detection rules from signature set. It realizes automation of unknown worm detection using new rules. Experiments prove that, this technology can find the unknown worm, and has high detection rate and low false positive rate.
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Computer Engineering. 2011, 37(20): 142-144. https://doi.org/10.3969/j.issn.1000-3428.2011.20.049Two party’s privacy is no protecting in string approximate matching of database. In order to resolve this problem, a secure query protocol is proposed. Based on the secure computing edit distance protocols, the vacant transmission protocols and the homomorphism encryption schemes are used under the effective protection of two party’s privacy to achieve string approximate matching query. Furthermore, the correctness, the security and the computational complexity of this scheme are as well analyzed. The results of analysis show that the proposed scheme is secure and efficient.
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Computer Engineering. 2011, 37(20): 145-148. https://doi.org/10.3969/j.issn.1000-3428.2011.20.050After taking binary image as watermark, this paper proposes a robust digital watermark arithmetic based on Discrete Cosine Transform(DCT) transformation domain. The watermark image is scrambled, and scramble number is used as the key when extracting watermark, then the watermark image and initial image respectively in block DCT transform are transformed. Each block of the watermark image is embedded into a plurality of the blocks of the initial image in order to make the embedded watermark have strong robustness. Experimental results prove that the arithmetic is of better robustness, invisibility, and resistance the attack to loss compression, cropping, randomly altered, white noise and so on.
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Computer Engineering. 2011, 37(20): 149-151. https://doi.org/10.3969/j.issn.1000-3428.2011.20.051To solve the problem that most route protocols lack secure mechanism, the route secure scheme is provided following trust. The trust evaluation model is given based on satellite network routing behavior. Trust metric is used to limit path selection. Route load balance is the goal of optimization. By improving existing route protocol, an on-demand secure routing protocol for satellite network is formed. The analysis result shows that it can resist a lot of inside attacks.
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Computer Engineering. 2011, 37(20): 152-153. https://doi.org/10.3969/j.issn.1000-3428.2011.20.052A semi-fragile watermark algorithm for image authentication is proposed, which has adaptability, and uses improved low-pass filter. The threshold values of grads are set according to resolving power of human eyes. Experimental results show that the proposed algorithm is robust to common data processing, which can resist JEPG top-level compression, as well the algorithm is fragile to malicious attack, such as abrasion, distortion, extrusion, lighting, and so on. Moreover, the tampered sort and area of watermarked image can be reflected.
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Computer Engineering. 2011, 37(20): 154-156. https://doi.org/10.3969/j.issn.1000-3428.2011.20.053This paper studies class incremental learning of P2P streaming traffic identification by using one-against-one Support Vector Machine(SVM) multi-classification. A new SVM class incremental learning algorithm——Class Incremental One-against-One Learning(CIOOL) is presented. CIOOL can adequately use former knowledge to construct a new multi-classifier without training over again. Experimental results indicate that CIOOL can decrease the time of training and memory consuming, and it is an effective algorithm to solve the problem of class incremental learning in P2P streaming traffic identification.
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Computer Engineering. 2011, 37(20): 157-159. https://doi.org/10.3969/j.issn.1000-3428.2011.20.054In order to solve the defects that Locally Linear Embedding(LLE) can not make full use of lable information in unsupervised machine learning, this paper proposes a kind of semi-supervised kernel-based local linear embedding algorithm. Taking into account measure of Euclidean distance is easy to destroy the manifold, this algorithm maps the raw data into a high dimensional kernel space, uses the distances in high-dimensional space instead of euclidean distance, and introduces the thought of semi-supervised learning to adjust the distance with label information, which is used for linear reconstruction and dimension reduction, and enhances the ability on dimension reduction. In the standard data sets, face and character database, experimental results show the recognition rate of novel method is 2% higher than the traditional local linear embedding algorithms.
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Computer Engineering. 2011, 37(20): 160-162. https://doi.org/10.3969/j.issn.1000-3428.2011.20.055This paper proposes a Layered Hidden Markov Model(LHMM) and entropy method to detect a gathering event in real-time. It uses aspect ratio eliminates the effect of other objects in the foreground, divides the video scene into blocks of regions, and relies on number and total speed statistics as the features. The features are encoded with LHMM to allow for the detection of gathering event. When the similarity between observation and the model is greater than the setted threshold, using optical flow calculates the entropy of the frame, entropy is greater than the setted threshold, it is judged to report a gathering event. Otherwise, not a gathering event, continuing processing next frame. Experimental results show the approach have higher recognition rate and robust.
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Computer Engineering. 2011, 37(20): 163-165. https://doi.org/10.3969/j.issn.1000-3428.2011.20.056This paper presents a boundary estimation method of human face images. On the basis of analysis of the face image features, the image is divided into five regions, it computes the variance to image each column. The human face left and right border are estimated based on the gradient to the variance sequence. According to the human face image characteristic and face shape features, the human face upper and lower boundaries are obtained. Experimental results prove the effectiveness of the method.
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Computer Engineering. 2011, 37(20): 166-168. https://doi.org/10.3969/j.issn.1000-3428.2011.20.057This paper proposes a fast face detection method in real-time video. It uses the DirectShow technology to grab the video frame, which has significantly increased system speed. After some pre-processes, the system detects the skin color by the statistical property of human skin to make the skin areas as the regions of interests. And these regions of interests are scanned by this improved AdaBoost algorithm for the further detection. Experimental results proves the validity of this method.
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Computer Engineering. 2011, 37(20): 169-171. https://doi.org/10.3969/j.issn.1000-3428.2011.20.058This paper proposes a Mean Shift tracking method for fusion image. It uses weighted average fusion and fusion scheme based on region target detection to make pixel-level dynamic image fusion of video from visible and infrared cameras. The tracking method uses Mean Shift algorithm. Fusion experiments results with real world image sequences are evaluated by the Root Mean Square(RMS) error of steady-state. It indicates that aiming at the target moving from one area to a different area, the proposed method is effective and efficient, meeting the robustness and real-time requirements.
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Computer Engineering. 2011, 37(20): 172-174. https://doi.org/10.3969/j.issn.1000-3428.2011.20.059A novel method based on Top-Down visual attention is proposed for object detection in remote sensing image. The method considers both object appearance cue and context cue in Top-Down attention. Object appearance cue is used to choose regions with the same features as object appearance to improve the efficiency. Context cue is used to focus the search on object context environment to confirm the correctness. Experimental results validate the good performance of the method in improving both the efficiency and the accuracy of object detection.
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Computer Engineering. 2011, 37(20): 175-177. https://doi.org/10.3969/j.issn.1000-3428.2011.20.060As there are still many difference between the remote sensing image from the same class, this paper proposes a new method of extracting features based on Slow Feature Analysis(SFA) and Gray Level Co-occurrence Matrix(GLCM). The image is first processed with SFA algorithm. It can eliminate the difference of the object from the same class as the biological characteristics of SFA. Then the GLCM feature is extracted from the SFA data. Results indicate that with the preprocessing of SFA, it can effectively reduce the diversity of samples from the same class and increase the distinguishability of the feature, the method is more effective and competitive than the conventional GLCM feature extraction method.
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Computer Engineering. 2011, 37(20): 178-179. https://doi.org/10.3969/j.issn.1000-3428.2011.20.061This paper proposes a text information extraction model based on improved Hidden Markov Model(HMM). It gives a new assumption of observation emission. And the absolute smoothing algorithm is used to smooth the parameters of the model. The model recovers the most-likely state sequence of the observation sequence and the reverse observation sequence with the Viterbi algorithm. It compares the results with each other based on N-Gram model, and outputs a more accurate result for the state sequence. Experimental results indicate that this model has effectively improved precision.
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Computer Engineering. 2011, 37(20): 180-182. https://doi.org/10.3969/j.issn.1000-3428.2011.20.062Selective ensemble classifiers can improve classification accuracy rate of data set. But for a specific data classification, the classifiers contained by ensemble can not be the best combination. Proceed from adaptation of data, two-phase selective ensemble of data streams is presented. According to location of data in the eigenspace, individual classifier is selected to classify this data. Theories and empirical analyses indicate this algorithm has more classification accuracy rate, in contrast with GASEN algorithm.
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Computer Engineering. 2011, 37(20): 183-185. https://doi.org/10.3969/j.issn.1000-3428.2011.20.063Traditional robust algorithms for estimating models in computer vision are inevitably affected by errors and outliers in the provided data, which makes estimation precision and stability low. This paper presents a Genetic Consistency Estimator(GCE) with strong robustness, combining global optimality of genetic algorithm and specialty of model estimation, to estimate geometric models in computer vision in a variety of errors and outliers probabilities. Experimental results prove GCE has greater precision and robustness compared with RANSAC, MAPSAC, MLESAC and other robust algorithms.
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Computer Engineering. 2011, 37(20): 186-188. https://doi.org/10.3969/j.issn.1000-3428.2011.20.064It always produces redundant computation when applying Belief Propagation(BP) algorithm to MEU problem. To improve such a situation, an optimization to BP is proposed that reuse last influent result instead of recomputing the marginal probability if the node is not significantly affected by the change of condition, and prove is given to confirm that the optimization does not significantly affect the influence result. A simulation by applying the optimized algorithm to combinatorial auctions gives the result that compare to the standard BP algorism, optimized algorism efficiently improve the efficiency of inference without significantly affect the quality of the solutions.
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Computer Engineering. 2011, 37(20): 189-190. https://doi.org/10.3969/j.issn.1000-3428.2011.20.065This paper presents an improved solution algorithm for nonlinear equations based on maximum entropy Harmony Search(HS) algorithm. It uses the aggregate function directly instead of nondifferentiable maximum value function, which can be converted to nonlinear equations as an unconstrained minimization problem, and uses harmony search algorithm for its solution. Numerical experimental results indicate that this algorithm has higher solution accuracy than Newton algorithm.
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Computer Engineering. 2011, 37(20): 191-193. https://doi.org/10.3969/j.issn.1000-3428.2011.20.066Aiming at that many quality problems are existed inevitably in detected data, including inefficacy, redundancy, error, missing, time dot excursion etc, the definition of data cleaning is proposed on the basis of sufficient study and analysis for the influence reasons of data quality, the cleaning rules and cleaning steps of “dirty data” are studied at the same time. And the proposed cleaning rules are calibrated with the detected data of loop vehicle detector. Results show that the recognition rates of “dirty data” is up to 90%.
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Computer Engineering. 2011, 37(20): 194-196. https://doi.org/10.3969/j.issn.1000-3428.2011.20.067Video stabilization is the key of robot vision. This paper establishes an image affine kinematics model with 6 parameters and its recurrence relations. Kanade-Lucas-Tomasi(KLT) feature matching method is designed based on grads. Optimization of sum of absolute difference is used to match feature points. Through analysis of over-determined image motion equations, observation model of intended motion parameters is derived, and the least squares algorithm is used to solve equations. Through reverse computing of kinematics model using filtered parameters, jitter is compensated and stabilized images are achieved. Experiments on autonomous mobile robot test-bed show that the feature points are uniform distributed and matching is faster by using KLT algorithm with sub-regional fast computing, and the relative parameters filter effect is smoother than the absolute parameters filtering.
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Computer Engineering. 2011, 37(20): 197-199. https://doi.org/10.3969/j.issn.1000-3428.2011.20.068Ad Hoc network has the characteristics of variable topology, energy constrained, and it demands higher about convergence speed of routing algorithm. According to these characteristics, this paper proposes a Genetic Algorithm-Similar Node-disjoint Mutipaths Routing(GA- SNDMR) algorithm. It improves genetic algorithm convergence speed through adopting selection and crossover based on certainty ratio, and makes the best of control information through modifying the forwarding conditions of nodes. Simulation results show that it is effective and superior to the simple nondisjoint multipath algorithm.
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Computer Engineering. 2011, 37(20): 200-202. https://doi.org/10.3969/j.issn.1000-3428.2011.20.069In order to make up the shortages of traditional cloning immune algorithm that it studies slowly when being applied in transformer fault diagnosis, has no classification ability and antibody space is small, this paper proposes a classification algorithm of antibody memory based on the principle that the antibodies recognize the antigens in the immune space and antibody memory function. By combining the clonal selection and the evolutionary algorithm, and learns the training antigen and subsidiary type information to build the fault information database which is composed of different types of detection aggregate. The learning speed of this algorithm is very fast while the affinity is high enough. At the same time, it has an expanded immunization search space and uses the linear relationship between the Artificial Recognition Ball(ARB) and the stimulation level for rapid diagnosis of the fault types. Experimental results show that the algorithm can improve the speed of diagnosis and the accuracy of fault diagnosis.
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Computer Engineering. 2011, 37(20): 203-205. https://doi.org/10.3969/j.issn.1000-3428.2011.20.070There are some algorithms which can detect similarity among documents, but these algorithms can not detect the duplicated of partial contents in documents. A new effective algorithm of the duplicated of partial contents detection in documents is put forward in this paper. It uses Particle Swarm Optimization(PSO) algorithm to search the optimized partial contents which is the most similar in two documents. For PSO algorithm, it provides the encoding of the particles. A new related coefficient of strings is defined for strings similarity. And the new evaluation function of PSO is designed based on the related coefficient function. The hybrid mutation PSO algorithm is used for searching the most similar partial contents quickly and accurately. Simulation experiments indicate that the algorithm can search the most similar partial contents in two documents effectively.
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Computer Engineering. 2011, 37(20): 206-207. https://doi.org/10.3969/j.issn.1000-3428.2011.20.071An approach based on inequality point segmentation Differential Evolution(DE) algorithm is presented to solve complex function numerical integral. DE is used to optimize the points in the integration interval, and make the rapid-change interval of function smaller or make the slow-change interval of function thicker, so that the more precise result is obtained. Numerical experimental results prove that the algorithm can compute integral for any functions in the usual sense, and compute oscillation function integral.
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Computer Engineering. 2011, 37(20): 208-210. https://doi.org/10.3969/j.issn.1000-3428.2011.20.072To improve on accuracy of Uyghur speech recognition, based on analysis of Uyghur characteristics, the framework of Uyghur speech recognition based on subword is developed for the first time. Pronunciation model of Uyghur word is given. How to build subword pronouncing dictionary, subword language model and acoustic model is described. Experiments are completed on a speech corpus and an unsupervised Uyghur word segmentation method is utilized to produce subwords. Experimental results show that Uyghur speech recognition based on subword can gain better recognition results.
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Computer Engineering. 2011, 37(20): 211-212. https://doi.org/10.3969/j.issn.1000-3428.2011.20.073Process Neural Network(PNN) can only receive time-varying continuous functions, can not receive discrete samples. To solve this problem, a training algorithm of PNN based on piecewise linear interpolation function is proposed. The discrete data of both sample functions and weight functions are transformed to piecewise linear functions, and then the integrals of product of two linear functions at a given sampling interval are computed. As a result of aggregation, these integrals are submitted to process neurons of PNN hide layer. The networks output is obtained. Experimental results show the availability of the proposed method.
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Computer Engineering. 2011, 37(20): 213-215. https://doi.org/10.3969/j.issn.1000-3428.2011.20.074The constriction factor Particle Swarm Optimization(PSO) algorithm is easily trapped in the local optimum and appeared premature convergence. An improved constriction factor PSO algorithm is proposed to overcome the local optimum. The improved algorithm introduces a position factor and speed factor parameter, if all particles are close to the global optimum and its velocity is less than the speed factor that it is set in advance, these particles are likely to be stagnant, a re-initialization is done to enhance these particles’ energy. When the algorithm is in local optimum, this method can disperse the particles and improve the diversity of the population and avoid premature convergence. Comparing the three multimodal functions’ simulation, the data can verify the performance of the improved algorithm, simulation result shows that the improved algorithm improves its convergence accuracy, and effectively avoids falling into local optimum.
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Computer Engineering. 2011, 37(20): 216-218. https://doi.org/10.3969/j.issn.1000-3428.2011.20.075This paper proposes a Dynamic Immune Optimization Algorithm(DIOA) based on biological immune system learning, memory and recognition functions to solve a class of high-dimensional dynamic optimization problem with constraints. The feasible antibodies are cloned and mutated, the infeasible antibodies are repaired, by means of the profit-density of antibody, and the new environmental population is generated by using memory cells of similar environment, which accelerates the convergence of algorithm. The algorithm is applied in the high-dimensional knapsack problems are solved in different environments. Experimental results prove that, compared with traditional algorithms, DIOA can track the optimum rapidly and has stronger convergent capability.
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Computer Engineering. 2011, 37(20): 219-222. https://doi.org/10.3969/j.issn.1000-3428.2011.20.076This paper introduces magic square problem, and analyzes 8-puzzle problem comparatively. It comprehensively discusses some issues relevant to solving magic square problem, such as whether there is a solution, minimum steps, state representation, state repetition judging, transition relation between states of magic square problem. It proposes a solution based on bidirectional Breadth-first Search(BFS) and state transition table. Experimental results prove that compared with other algorithms, the algorithm proposed is efficient and stable, which meets the requirements of real-time solving and presentation of magic square problem.
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Computer Engineering. 2011, 37(20): 223-226. https://doi.org/10.3969/j.issn.1000-3428.2011.20.077Aiming at the defects of the low convergence rate and the immature convergence in the traditional evolutionary algorithm, this paper combines quantum optimization algorithms with evolutionary algorithm, puts forward the quantum evolutionary algorithm. It adopts quantum bits code chromosome, and constructs a new entirety interference crossover which acts on general chromosome crossover manipulation. Experiment proves that the algorithm can bring abundant population, improve the choiceness mode probability of population evolution, and quicken the convergence rate. It can avoid population fall into local optimums, and the precocity.
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Computer Engineering. 2011, 37(20): 227-229. https://doi.org/10.3969/j.issn.1000-3428.2011.20.078Aiming at the high computiaion complex for traditional cyclic spectrum, this paper presents a cyclic spectrum recognition based spectrum sensing algorithm, which uses correlation matrix instead of frequency domain smoothing to compute spectrum feature. This algorithm greately reduces the complexity while distinguish between noise and useful signal accurately. A test platform is constructed based on software defined radios to demonstrate the effectiveness of the method. Experimental results show the spectrum holes of different primary users can be detected with high accuracy greater than 90% and low complexity. The performance can satisfy the requirement of spectrum sensing in cognitive radio.
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Computer Engineering. 2011, 37(20): 230-232. https://doi.org/10.3969/j.issn.1000-3428.2011.20.079In order to resolve the incompatibility of communication mode and communication protocol for electronic products, this paper presents a new bridge which supports both variety of wireless interfaces in hardware and multi-protocol in software. It not only includes translation between UPnP protocol and Intelligent Grouping and Resource Sharing(IGRS) protocol but also includes virtualization of ZigBee device and Bluetooth device. The solution perfectly resolves the connectivity among UPnP, IGRS, ZigBee and Bluetooth.
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Computer Engineering. 2011, 37(20): 233-235. https://doi.org/10.3969/j.issn.1000-3428.2011.20.080According to the demand of 3G network for family network in future, this paper proposes a structure of Open Service Gateway Initiative(OSGi)/Session Initiation Protocol(SIP) communication based on socket. The structure is based on Android platform which has a good transplantation and solves the problem of data interaction between the SIP network layer and the OSGi application layer, while it provides the rich gateway service for the remote users used of the rich ability of session which the SIP protocol has. The result of implementation proves that the structure is universal, which can also be used in medical care, monitoring and environmental monitoring in practical application.
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Computer Engineering. 2011, 37(20): 236-238. https://doi.org/10.3969/j.issn.1000-3428.2011.20.081Due to current serious problem about electric vehicle theft, this paper introduces a new type of electric vehicle anti-theft system combined with Internet of Things technology. The system is based on MCF52223 microcontroller in Freescale Coldfire family, using ZigBee and General Packet Radio Service(GPRS) to realize electronic tags communication and network interconnect. In addition, multi-alarm is applied to this system, which indicates suspicious vehicle information intuitively. The system brings good effect to electric vehicle anti-theft.
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Computer Engineering. 2011, 37(20): 239-241. https://doi.org/10.3969/j.issn.1000-3428.2011.20.082With respect to the requirement of high speed RapidIO signal connection of high performance embedded system, this paper proposes a method for a front RapidIO interface on System-on-a-Programmable-Chip(SoPC). The method builds message transmission logic among RapidIO interface, Low Voltage Differential Signal(LVDS) image interface and RS422 control interface with RapidIO IP core and hardware programming based on the development platform of Xilinx VirtexII Pro. Hardware architecture diagrams and key design thoughts are introduced and the software architecture is presented.
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Computer Engineering. 2011, 37(20): 242-245. https://doi.org/10.3969/j.issn.1000-3428.2011.20.083The serial ports must be expanded when the flight controlling computer communicates with exterior devices by multi-serial communi- cation, with the characteristic of too many pins and big figure, usual Universal Asynchronous Receiver/Transmitter(UART) chip makes the circuit large and high-consumed. Aiming at these problems, this paper chooses a Field Programmable Gate Array(FPGA) chip, programming with verilog HDL, designs and integrates ten UART cells, data-receive controller, data-send controller and dual-port Random Access Memory(RAM), achieves ten channels of serial communication of the flight controlling computer, and manages to make the circuit much simpler. It is confirmed that the design scheme is correct by simulating and test the design result with ISE9.1i.
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Computer Engineering. 2011, 37(20): 246-248. https://doi.org/10.3969/j.issn.1000-3428.2011.20.084Owing to the problem of Electronic Control Unit(ECU) calibration system poor portability lead to ECU development inefficient, this paper composes a development method based on resource library which abstracts the common part of the calibration system and packages it to a series of resource library functions, supplies for application layer and basic software layer called, and calibration resource library function call hardware driver program which accord with AUTOSAR specification to realize system function. When the software functionality or develop object change, it only need to replace the related software layers. Instances result proves that this method can remarkable increase portable and reliability of the calibration system.
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Computer Engineering. 2011, 37(20): 249-251. https://doi.org/10.3969/j.issn.1000-3428.2011.20.085High real time performance is required by the embedded operating system based on ARINC653 standard. It analyzes the ARINC653 partition schedule algorithm, the problem is solved that the spare time is not being used. This paper also proposes a schedule model with spare time, and designs spare time share partition schedule algorithm using priority bitmap algorithm and two-level schedule mechanism. Theoretical analysis shows that spare time share partition schedule reduces the average response time of task.
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Computer Engineering. 2011, 37(20): 252-254. https://doi.org/10.3969/j.issn.1000-3428.2011.20.086Current Field Programmable Gate Array(FPGA) chip can only be erased and configured periodically and repeatedly during the Single Event Upset(SEU) error detection, and this is not a continuous error detection and correction method. Aiming at this problem, this paper presents a continuous SEU hard core detection circuit with real-time error detection information output for external circuits. The circuit improves the traditional FPGA frame storage structureca and can work continuously for read-back Cyclic Redundancy Check(CRC) without affecting the normal state of FPGA. The design has been used in FDP3P7 FPGA chip which is designed independently. Test results indicate that the SEU hard core detection circuit can work continuously on the configuration bit-stream read-back CRC in the 50 MHz frequency and real-time error detection information output correctly.
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Computer Engineering. 2011, 37(20): 255-257. https://doi.org/10.3969/j.issn.1000-3428.2011.20.087Through analysis of the characteristics of merging sorting and quick sorting, this paper presents two optimized algorithms specially for Loongson 3A CPU’s features. To boost the performance, it adapts various optimizing techniques including utilize the characteristic of memory access, copy optimization, loop unrolling, operation exchanging and compounding different basic sorting algorithms. Without losing the robustness, sorting performance on Loongson 3A is improved by about 16.9% to 90.5% in different situations, compared to the sorting function in Glibc 2.11.
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Computer Engineering. 2011, 37(20): 258-260. https://doi.org/10.3969/j.issn.1000-3428.2011.20.088A Network-on-Chip(NoC) routing algorithm is proposed to improve the routing efficiency, it is an adaptive and minimal-path algorithm. By employing multi-priority before data transfer, it increases system’s throughput and reduces the network latency. The algorithm is simulated on a 4×4 2D mesh network using the NIRGAM simulation platform. By comparing with the other algorithms, it shows that the algorithm has a better performance in hotspot traffic pattern.
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Computer Engineering. 2011, 37(20): 261-263. https://doi.org/10.3969/j.issn.1000-3428.2011.20.089Based on the needs of structured storage of information in the forest products trade text messages information push and combined with the basic principle of semantic recognition and the rule-based information extraction, a research on forest products trade text messages structuring based on semantic is proposed. Took advantage of the characteristics of forest products trade text messages, this paper defines the level of text recognition rules in the trade text messages, uses match identification rules of creating databases and data tables, defines the regular expressions with matching identification rules and the rules of intercept text recognition to extract the special factual information. The information is stored in the database as a structured form. Through the text structured information extraction in the trade text messages, it proves that the research has good value in the forest products trade information push.
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Computer Engineering. 2011, 37(20): 264-267. https://doi.org/10.3969/j.issn.1000-3428.2011.20.090In mobile computing environment, low concurrency and too many unnecessary transaction restarting exist in original Optimistic Concurrency Control Protocol(OCCP). To solve these problems, a new optimistic transaction concurrency protocol, BOCC-RW, which is based on read and write timestamp, is proposed in mobile computing environment. Simulation experiment shows that the protocol can improve the concurrency of transaction and reduce the probability of transaction restarting. Experiment results show that compared with the original optimistic protocol and optimistic protocol based on timestamp, the BOCC-RW is more applicable in mobile computing environment.
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Computer Engineering. 2011, 37(20): 268-270. https://doi.org/10.3969/j.issn.1000-3428.2011.20.091A new method to optimize the computing program of coherent integration based on Single Instruction Multiple Data(SIMD) is pro- posed to deal with the problem of real-time in the software GPS receiver, and the method of SIMD and pipeline optimization is discussed respectively. This paper analyzes the structure of following loop and SIMD instructs and coherent integration accumulation operation quantity, and uses Multi Media eXtension(MMX) order set to optimize the pipeline. Experimental results show that, the time of completing process of 1 second length data is about 0.7 second. The computation is only 6.5% of general Single Instruction Single Data(SISD) instruction, which effectively ensures the implementation of pure real-time software receiver.
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Computer Engineering. 2011, 37(20): 271-273. https://doi.org/10.3969/j.issn.1000-3428.2011.20.092A compound deformation algorithm based on physics is proposed, which is adapted to the conventional simulation of the deformable objects that is poor at dynamic performance. This new algorithm is decoupled local and global deformation by using a filling sphere modeling approach. Through layered rendering of virtual force, the spring-mass system on the surface enhances immersion for virtual environment. For the problem of deformation hysteresis, correcting the position of barycenter using shape matching makes the result of dynamic simulation more exact.
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Computer Engineering. 2011, 37(20): 274-276. https://doi.org/10.3969/j.issn.1000-3428.2011.20.093On the basis of thorough analysis on the charateristics of m-maintenance policy in k/N redundancy system, the spare parts requirements model based on Multi-Agent simulation is presented. The simulation represents the two objects as two kind of Agents: Shop Replaceable Unit(SRU) Agent for working component and SparePart Agent for spare parts, and the state chart models are constructed for both Agents. The control of states for each agent is event-driven, which can inderectly control the system behavior. The effectiveness of the approach is testified by an example.
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Computer Engineering. 2011, 37(20): 277-279. https://doi.org/10.3969/j.issn.1000-3428.2011.20.094Using the dynamic binary translator QEMU as a research platform, this paper analyzes the dynamic binary translation technology used in the development of the simulator, studies in detail QEMU with the translation mechanism, optimization strategy, and key technologies and analyzes important related code. Simulation tests the performance of CPU, and combining phases test results, finds the restriction of the CPU performance simulation key stages, it provides reference for optimization.
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Computer Engineering. 2011, 37(20): 280-281. https://doi.org/10.3969/j.issn.1000-3428.2011.20.095The sparse user-item matrix often hurts the performance of recommendation system. Aiming at this problem, an object image recommendation algorithm based on multi-instance learning is proposed. The images are regarded as bags and the segmented regions as instances. The Diverse Density(DD) function is adopted to search the maximum DD point; Next the positive and negative images is used to measure the users’ similarity. The similarity result is integrated with the traditional cosine similarity. Experimental results show that, the algorithm can improve the recommendation performance.
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Computer Engineering. 2011, 37(20): 282-284. https://doi.org/10.3969/j.issn.1000-3428.2011.20.096This paper proposes a novel 3D body based multi-resolution video segmentation algorithm for solving some difficulties in video area, such as the tremendous data volume and temporally inconsistency. It segments the whole video volume to ensure the temporally coherent result. Meanwhile, it uses the multi-resolution method to reduce the computational cost. Experimental results show that, the approach greatly reduces the time and space cost of the traditional segmentation approach and revises the part segmentation result of continuation frame.
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Computer Engineering. 2011, 37(20): 285-286. https://doi.org/10.3969/j.issn.1000-3428.2011.20.097The self-time-delay chaos synchronization is researched. The double self-time-delay is introduced based on the Lorenz chaotic system, and the new attractor is obtained which is different from the Lorenz chaotic system. The self-time-delay chaos synchronization is achieved for the Lorenz chaotic system by designing the time-delay synchronization controller and the parameter identifier. The validity of this method is proved by the numerical simulation based on Matlab, and the self-time-delay chaos system synchronizes rapidly.
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Computer Engineering. 2011, 37(20): 287-290. https://doi.org/TP301.6A virtual machine technology for pervasive computing environment is designed to improve the utilization of resources and services and compatibility issues of traditional application in pervasive computing environment. The technology is a combination of virtual machine model and device request broker. Device request broker isolates the complex network in pervasive computing and provides a uniform hardware platform for upper application. Virtual machine supports multiple pervasive computing applications to run at same time. Experimental results show that, the virtualization technology can be compatible with traditional application and improve the utilization of resources and services.
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Computer Engineering. 2011, 37(20): 291-292. https://doi.org/10.3969/j.issn.1000-3428.2011.20.099In the pervasive environments, complexity of computing environment makes the user hard to control the states of the system with the predefined actions. The diversity of users, their tasks and techniques demands the correct presentation of the system’s states to be considered at the beginning of design. For this purpose, this paper presents a new approach to user interface design with scenarios, based on perceptual control theory. The main point of the approach is to derive the objects that are significant for the user understanding and controlling the system, and the means for the control, from the analysis of scenarios. Result gained from the process is used for the re-design of scenarios. The approach is concerned with user’s task and the purpose of which is to satisfy the user’s needs. Case analysis show the availability and effectivity of this new approach.
2024
Volume 50 No 4
Volume 50 No 4
(Started in 1975, Monthly)
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428