05 April 2010, Volume 36 Issue 7
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Computer Engineering. 2010, 36(7): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2010.07.001A novel quick store-and-forwarding mechanism-based time synchronization method is proposed for strip-based Wireless Sensor Networks(WSNs). Combining store-and-forwarding mechanism with linear regression, this method achieves high accuracy and constant setup time. Experimental results show the method has micro second synchronization accuracy and constant synchronization setup time.
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Computer Engineering. 2010, 36(7): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2010.07.002A new algorithm called Special Node Node-Disjoint Multipath Routing(SNNDMR) is proposed to calculate the key node that may exist among the node-disjoint routing paths. The algorithm makes the data packets via a unipath to reach at the former node of the key node. The data packets are routed to multiple node-disjoint paths. In this way, data packets can be routed to the destination node by node-disjoint multipath at the same time. Simulation experimental results show that, compared with the existed Node-Disjoint Multipath Routing(NDMR) algorithm, the new algorithm improves the packet delivery ratio and reduces end-to-end delay time. If there are no key nodes, the performance of this algorithm is almost as same as NDMR’s.
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Computer Engineering. 2010, 36(7): 7-10,1. https://doi.org/10.3969/j.issn.1000-3428.2010.07.003A Rating-Supervised Protocol(RSP)-based reputation mechanism is presented. By depicting autonomic elements trust degree on service and on rating differently and associating them dynamically, the non-rating, malicious rating can be distinguished and punished. Meanwhile, autonomic elements are stimulated to participate actively and rate honestly. The distributed implementation is provided. Experimental results show this RSP-based reputation mechanism can realize the differential service based on rating trustworthiness, and efficiently resist malicious attack.
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Computer Engineering. 2010, 36(7): 11-13. https://doi.org/10.3969/j.issn.1000-3428.2010.07.004In order to solve the fairness problem in 802.11e networks, a method called DTAF(Dynamic TXOP Allocation for Fairness) is proposed, which utilizes the collision times to estimate contention degree before transmission, turns TXOP, and at the same time, solves the unfairness problem in the networks employing the multi-rate scheme. Theoretic analysis and simulaiton results show that DTAF has better performance in retransmission times, packets average transmission delay and fairness among stations employing varying data rates.
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Computer Engineering. 2010, 36(7): 14-16. https://doi.org/10.3969/j.issn.1000-3428.2010.07.005In structural health monitoring of Wireless Sensor Network(WSN), a faulty sensor may produce incorrect data and transmit them to the others. It consumes the limited energy and bandwidth of WSN. The base station may make inappropriate decision when it receives the incorrect data. Aiming at this problem, a distributed fault detection algorithm for WSN is presented. Faulty sensor nodes are identified based on comparisons between neighboring nodes and dissemination of the decision made at each node. The whole node detection is implemented. The method to improve fault diagnosis rate in different average node degree is proposed. Experimental results show that sensor nodes with permanent faults are identified with high accuracy for a wide range of fault rates.
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Computer Engineering. 2010, 36(7): 17-19. https://doi.org/10.3969/j.issn.1000-3428.2010.07.006Aiming at the suboptimal route selection problem in the Interior Gateway Protocol(IGP) cost induced by route reflection, this paper proposes an algorithm for optimal egress point check of iBGP route based on route reflection. This algorithm is operated in large-scale AS using C-BGP simulation. The results show that more than 20% potential suboptimal route can be obtained while there are parallel next-hops existing in the network.
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Computer Engineering. 2010, 36(7): 20-22,2. https://doi.org/10.3969/j.issn.1000-3428.2010.07.007In order to preserve the information of source remote sensing image, improve its spacial resolution and make it appropriate for people to observe, this paper proposes the Contourlet bi-cubic interpolation algorithm. It uses bi-cubic interpolation to do similar transformation, and obtains interpolation image with higher resolution ratio than the original image by inverse transformation. Experimental results show that the algorithm can get higher PSNR and better image detail effect than the bi-cubic interpolation and wavelet bi-cubic interpolation.
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Computer Engineering. 2010, 36(7): 23-26. https://doi.org/10.3969/j.issn.1000-3428.2010.07.008According to the features of dynamic changes of the satellite network topology, the limited ability and high-speed movement of the satellite node, this paper proposes a management cluster generation algorithm for satellite network based on contract network model to reduce the time delay of network management and communication load between the management station and the agent on the satellite node. The communication primitive for satellite network management cluster is designed and implemented. The primitive is accorded with ASN.1. Experimental results show that the primitive can support the establishment of satellite network management cluster.
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Computer Engineering. 2010, 36(7): 27-29. https://doi.org/10.3969/j.issn.1000-3428.2010.07.009Aiming at the storage management problem of archival data, this paper proposes the AStore archival storage architecture. The data storage and management strategy for the archival storage system is designed by using data fingerprint, data compression, data chunk-dividing and data de-duplication technologies. It tests and analyzes the storage system performance different parameters. Experimental results demonstrate that the strategy can reduce the data redundancy, improve the space utilization efficiency and access performance of the storage system.
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Computer Engineering. 2010, 36(7): 30-32. https://doi.org/10.3969/j.issn.1000-3428.2010.07.010During the process of relational database integrated to XML, relational data is translated for once by static transform method. This method can not meet the translation needs of special relational data in some applications. In order to realize dynamic translation, this paper proposes a dynamic translation system based on the universal mapping model of static translation system and gives the relevant dynamic translation algorihtm. The efficiency and generability of this algorithm are verified by examples.
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Computer Engineering. 2010, 36(7): 33-35. https://doi.org/10.3969/j.issn.1000-3428.2010.07.011Aiming at the characteristics and demands of working flow of Software Defined Radio(SDR) receiver, this paper develops a real-time data acquisition software. It works with intermediate frequency signal in Windows XP. Compared with single thread techniques, multi-thread can guarantee real-time performance and efficiency. The Event kernel object provided by operating system is used as the thread synchronization mechanism, so the interoperability between different threads is realized. Every thread has proper access to the same share resources. To some extent, the use of MFC makes codes reusable. The software is designed flexibly, and it is convenient and easy to maintain.
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Computer Engineering. 2010, 36(7): 36-38. https://doi.org/10.3969/j.issn.1000-3428.2010.07.012The traditional collaborative filtering technology based on rating can not find the right criteria. It is difficult to find exact relation for large ratings aggregate of items, so the expression of personalize is influenced. A collaborative filtering recommendation algorithm based on multiple ranked choosing domains is proposed, which computes comparison of preference value by relevance of sliding matched items in choosing domains. It proposes a novel conservative similarity algorithm for profile matrix, and implements predicted ratings by the similar users. Experimental results show that the proposed method can efficiently ease the sparsity of data, and significantly improve recommender precision in predicted ratings.
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Computer Engineering. 2010, 36(7): 39-41. https://doi.org/10.3969/j.issn.1000-3428.2010.07.013Model-based approach alleviates the discrepancies between software functional models and the implementation by automatically transforming models. Constructing real-time tasks, or operating system-level processes/threads, from the components of software design models is crucial to the model-based development of embedded control software. Temporal consistency is considered in the model, the absolute temporal consistency ensures the data is valid, and the relative temporal consistency ensures the data is available.
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Computer Engineering. 2010, 36(7): 42-44. https://doi.org/10.3969/j.issn.1000-3428.2010.07.014This paper proposes an improved critical chain management method based on triangular fuzzy number against the defect of application of critical chain in software project schedule management. It estimates activity durations with triangular fuzzy number, and takes the value whose degree of belonging to the activity durations is 1 as the highest possibility time of activity. Based on the highest possibility time of activity, activity-network is made. The project critical chain under resource constraints is built. Uncertainty in the project is absorbed through inserting buffers. Schedule control is performed by monitoring the penetration level in the buffers. Application process of the method is illustrated with a case, which proves the method is effective and practical.
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Computer Engineering. 2010, 36(7): 45-46,4. https://doi.org/10.3969/j.issn.1000-3428.2010.07.015Based on the normal functions of the Web services, this paper proposes a feasible way that annotates the meaning of the data received from a Web service by the semantic annotation. The Web services users who understand better the meanings of Web data criteria can operate the received data correctly in their applications by the additional semantic information which is described by the CIDOC CRM and is capable of revealing the meanings and the multilevel relations of data.
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Computer Engineering. 2010, 36(7): 47-49. https://doi.org/10.3969/j.issn.1000-3428.2010.07.016Aiming at the problems that many defects, e.g., obscure error generation-scenario and lacking of formalization exist in field of code error research, this paper represents definition of code error pattern based on definition of pattern. It investigates the formalization description of code error pattern based on the three key elements of the code error pattern. It adopts extended pattern description language-based formalization description method. This method reflects both the direct scenario and the error code structure in the same concept. This paper represents a case study and confirms the rationality of the code error pattern concept and the effectiveness of the formalization description method.
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Computer Engineering. 2010, 36(7): 50-51,5. https://doi.org/10.3969/j.issn.1000-3428.2010.07.017Aiming at the problem of jumping from one ontology-level space to another in traditional ontology formalization process, this paper introduces the idea of granular computing to the field of ontology modeling, which uses the theory of property granular quotient space to construct ontology formalization model and defines various parts of it. The ontology formalization model based on property granular quotient space is tested, whose results prove that the model can meet reasoning relations among ontological levels better.
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Computer Engineering. 2010, 36(7): 52-54. https://doi.org/10.3969/j.issn.1000-3428.2010.07.018This paper analyzes the work principle and data transmission performance of Ajax, and discusses the difference between XML and JSON by experiments with a focus on the format of response data returned. Some suggestions to choose either based on the current application scenarios are given, an optimized model of Ajax which is more efficient and secure is summarized, which improves the shortcomings such as data response redundancy caused by Ajax nowadays.
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Computer Engineering. 2010, 36(7): 55-57. https://doi.org/10.3969/j.issn.1000-3428.2010.07.019Considering the impact of the property number and weight on association rules, this paper presents a new method for mining weighted association rules, which can hold the downward closed property by using an improved model of weighted support measurements when mining association rules. Compared with Apriori algorithm and horizontal weighted association rules mining method, it proves that the method can quickly and efficiently mine important association rules.
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Computer Engineering. 2010, 36(7): 58-60. https://doi.org/10.3969/j.issn.1000-3428.2010.07.020This paper applies decision tree method to obtain better service provision in the farmer professional cooperatives. Service data are set up from the traffic data, and the decision tree classification model based on production is built with the knowledge rules generated to find main factors underlying knowledge of the rules. From the rules, the service promotion facts are learned, which enrich the content of the cooperative’s services, far more broaden the service capabilities, and give a better direction on the production.
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Computer Engineering. 2010, 36(7): 61-62,6. https://doi.org/10.3969/j.issn.1000-3428.2010.07.021Based on the idea of time and space partitioning, this paper designs synopsis data structures which contains the distributed status of data stream to support different data mining tasks such as classifying, clustering and association rules discovery. Three kinds of measures are researched to control the potential huge requirement of memory caused by space partitioning, so that the synopsis’ memory requirement and the number of I/O are balanced.
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Computer Engineering. 2010, 36(7): 63-65. https://doi.org/10.3969/j.issn.1000-3428.2010.07.022Aiming at the construction problem of complex system, based on Rational Unified Process(RUP) method, this paper analyzes function and interaction of three kinds of framework view for Web-Based Interactive Assistant Learning System(WBIALS), and carries on architecture modeling for WBIALS. It develops its software system using use-case driven and incremental and iterative mode from global prospect. Application result shows that this software system has consistency, completeness and interoperability.
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Computer Engineering. 2010, 36(7): 66-67,7. https://doi.org/10.3969/j.issn.1000-3428.2010.07.023Aiming at the problem that large data in deep Web can not be indexed by traditional searching engine, this paper uses an improved heuristic rules to identify entrance query of form in extractive Web pages. It adopts improved similarity matching algorithm based on semantic to fill form content when form tag matching with content. Experimental results show that the veracity rate of extracted form label is 94.23%, success rate of the matching is 88.83% and filling form control is 95.43%.
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Computer Engineering. 2010, 36(7): 68-70. https://doi.org/10.3969/j.issn.1000-3428.2010.07.024In the aspect of the property in ontology concepts, an ontology mapping approach based on property structure is proposed in this paper. With multi-aspect information of the property, property mapping is progressed in order to build Property Structure Tree(PST). With PST, layer relation between concept properties is discovered, which is used to measure the semantic similarity of ontology concepts. Experimental result indicates that property structure is one of the factors infecting ontology mapping, and this approach is effective.
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Computer Engineering. 2010, 36(7): 71-72,7. https://doi.org/10.3969/j.issn.1000-3428.2010.07.025In order to resolve the tight coupling problem between domain model and database, this paper proposes Object Relation Mapping(ORM) architecture based on C++. It gives some key technologies and sectional implement codes about abstract base classes, mapper registry classes, realizes relation mapping and lifecycle management of domain object through intelligent pointer. The ORM subsystem designed and realized based on this architecture is applied in equipment state monitor and security evaluation system, its operation situation is well.
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Computer Engineering. 2010, 36(7): 73-75. https://doi.org/10.3969/j.issn.1000-3428.2010.07.026Aiming at the problem that the precision of ontology mapping is not good, this paper proposes a method which verifies the result of ontology mapping based on natural language processing method. Through the heuristic method for compound word processing, and the analysis of parser trees of the glosses in WordNet, it extracts the related words for the reference ontology and target ontology. Experimental result shows that the method can improve the precision of the ontology mapping.
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Computer Engineering. 2010, 36(7): 76-78,8. https://doi.org/10.3969/j.issn.1000-3428.2010.07.027Aiming at the problem of high complexity in calculation and memory for DSmT mixing rule, this paper proposes a matrix calculation algorithm. This algorithm codes the basic element of discernment frame into a set, simplifies procedure for hybrid rule of combination. Experimental results show that this algorithm makes execution time exponential rising with variation of discernment frame size, and linear variation with variation of evidence source and focal element, it avoids high complexity effectively.
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Computer Engineering. 2010, 36(7): 79-81. https://doi.org/10.3969/j.issn.1000-3428.2010.07.028Aiming at the problem that BBS posts browsing mechanism is not consummate and topics discovery has low efficiency, a new text clustering method based on BBS hot topics discovery is put forward. Document vectors including keywords are added, the distance between them is computed and the two classes with a minimum distance are merged in turn to obtain equality for the vector number of final classes. The posts with hierarchical menu are organized, so as to guide users to conveniently browse the posts that they are really interested in and also know well the current hot topics on BBS. Experimental result proves that the new clustering method is more proper for browsing the hot topics on BBS than regular ones.
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Computer Engineering. 2010, 36(7): 82-83,8. https://doi.org/10.3969/j.issn.1000-3428.2010.07.029This paper researches on quick and efficient formal analysis of security protocol, and presents the concept of trust domain. Diagrammatic analysis is adopted, which makes deduction of protocol more clear and intuitive. This method analyzes the trust domain of protocol entity directly, which makes analysis easier. Experimental results show that the method is faster and more intuitive compared with traditional methods. It provides ways and basis for finding redundancies of security protocols.
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Computer Engineering. 2010, 36(7): 84-86. https://doi.org/10.3969/j.issn.1000-3428.2010.07.030Aiming at the theme of accessing heterogeneous data transparently, a model for the access to data resources in the grid is put forward in this paper, taking advantage of Lightweight Directory Access Protocol(LDAP) and Language Integrated Query(LINQ) to enhance the resource sharing and advance the support of the access to existing data for applications in the background of the grid. The structure and key technologies are emphasized. This model realizes the access to multi-resource, such as SQL database, XML document, ADO.NET dataset, list in memory.
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Computer Engineering. 2010, 36(7): 87-89,9. https://doi.org/10.3969/j.issn.1000-3428.2010.07.031Aiming at the problem of balanced energy consumption in Wireless Sensor Network(WSN), a route protocol is proposed based on polymorphic ant colony algorithm. It integrates the spare energy information of the nodes into their pheromone construction, adopting the technology of cycle transmission and data fusion. Simulation experiments show that compared with Leach protocol, adopting the proposed protocol, eight-two percent of the nodes have longer life cycle and forty-eight percent more data packets can be transmitted. The proposed protocol is implemented in a real WSN with thirty-one nodes. Experimental results confirm the validity of the protocol.
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Computer Engineering. 2010, 36(7): 90-92. https://doi.org/10.3969/j.issn.1000-3428.2010.07.032Aiming at the short-term priority problem in Wireless Mesh Networks(WMN), a medium access control algorithm with Quality of Service(QoS) guarantee is proposed. By suspending transmissions of low-priority traffic when traffic load is heavy, the proposed algorithm can provide more opportunities of channel access and QoS guarantee to high-priority traffic. Simulation results show that comparied with the IEEE802.11e EDCA, this algorithm can reduce the delay of real-time traffic and improve the throughput.
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Computer Engineering. 2010, 36(7): 93-95,9. https://doi.org/10.3969/j.issn.1000-3428.2010.07.033Aiming at the topology mismatch problem in structured Peer-to-Peer(P2P) network system, a self-organizing clustering and self-determination clustering leader routing algorithm is presented. The algorithm selects a set of neighbors clustering for each node. Each node becomes the leader of own neighbors clustering according to its power. Nodes find resources in accordance with their neighbors clustering, the leading neighbors clustering and the chord algorithm. Experimental results show that the algorithm improves routing performance, gains high route success rate and solves the topology mismatch problem.
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Computer Engineering. 2010, 36(7): 96-98. https://doi.org/10.3969/j.issn.1000-3428.2010.07.034To overcome the deficiency in layer-2 device topology discovery for most network management tools, this paper puts forward a topology discovery algorithm based on address filtering. The algorithm acquires network device information through standard Simple Network Management Protocol(SNMP), and builds up the network topology map successfully by filtering address forwarding table information of layer-2 device. The algorithm eliminates the drawbacks of traditional topology discovery algorithms that must depend on complete address forwarding table or private device information, and is endowed with the characteristics of practicability and availability.
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Computer Engineering. 2010, 36(7): 99-101. https://doi.org/10.3969/j.issn.1000-3428.2010.07.035This paper analyzes the shortcomings of fixed protocol expenses that occur under network topologies with different degrees of stability for Adhoc On-demand Distance Vector(AODV) protocol which occupy network bandwith. It puts forward a method to transmit the Hello message through the auto-adapted time-lag to control the power, to enhance the network bandwidth, and to reduce the convergent time. This algorithm transmits the Hello message by adjusting time-lag automatically according to the change emergency of the network topology. Simulation tests indicate that on the same premise of other conditions, network bandwidth is more reasonably used and network performance is optimized by applying auto-adapted time-lag to transmit the Hello message.
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Computer Engineering. 2010, 36(7): 102-104. https://doi.org/10.3969/j.issn.1000-3428.2010.07.036The resource schedule algorithms in hybrid-traffic WCDMA system must differentiate the service to guarantee the demand of QoS. Therefore, on the research of Modified Largest Weighted Delay First algorithm(M-LWDF), a hybrid-services resource schedule algorithm which guarantees the demand of QoS is proposed with the usage of QoS monitoring mechanism. It considers both the delay priority and throughput priority during the service schedule period, and it guarantees the transmission time delay during the resource allocation period. Simulation results show that the algorithm is superior to the existing schedule algorithms in the level of delay and throughput.
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Computer Engineering. 2010, 36(7): 105-107. https://doi.org/10.3969/j.issn.1000-3428.2010.07.037At present, the major Wireless Sensor Network(WSN) clustering routing protocols proposed are based on uniform distribution of nodes, the energy balance of consumption idealized assumptions, but in a real work environment, these assumptions often lead to cluster preferred to take unreasonable. To address the above issues, an energy efficient distributed cluster heads selection algorithm of sensor networks is proposed. When selecting cluster heads, the algorithm considers various factors such as the network topology characteristics and the node’s energy consumption. Simulation results show that sensor network using this algorithm has better applicability and its useful life improves over doubled than traditional algorithms such as LEACH.
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Computer Engineering. 2010, 36(7): 108-111,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.038Based on the research of ZigBee Network’s present routing strategy, this paper proposes a routing strategy with the goal to save network’s energy cost and to balance data loading among nodes. The new strategy improves ZigBee Network’s cluster-tree topology structure and the present ZigBee Routing(ZBR) strategy which is based on cluster-tree algorithm and AODVjr algorithm. The strategy tries its best to reduce routing overhead and to protect low energy nodes at the same time. According to simulation results, it proves that strategy can effectively reduce energy cost and balance loading, successfully prolongs network’s lifetime.
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Computer Engineering. 2010, 36(7): 112-114,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.039Aiming at the system instability of structured P2P model which is caused by the heterogeneity of nodes in model, this paper proposes a Hybrid Structure P2P network based on the Chord(HSChord). The model is combined with the advantages of hybrid P2P model. According to the nodes’ processing power, it divides nodes into super-nodes and ordinary-nodes. In this model, some super-nodes are organized into the same group, and manage the ordinary-nodes to improve system stability. The model proposes search algorithm which is based on topology-aware. The algorithm can solve the routing detour which is caused by DHT technical inquiries better. Experimental results show that the search algorithm can reduce the query delay and improve the efficiency of query.
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Computer Engineering. 2010, 36(7): 115-118. https://doi.org/10.3969/j.issn.1000-3428.2010.07.040Internet topology modeling is the foundation of Internet performance research. Power-Law Out-Degree(PLOD) algorithm is an AS-level Internet topology generating algorithm. But it cannot guarantee the connectivity of the topology and has the “credit overstock” problem. Based on PLOD, Power-Law Degree Algorithm(PLDA) is proposed. It adds the connectivity check and gives link preference to nodes which have more out-degrees. PLDA ensures the connectivity and mitigates the “credit overstock” problem. Experimental results indicate feasibility and efficiency of PLDA.
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Computer Engineering. 2010, 36(7): 119-121. https://doi.org/10.3969/j.issn.1000-3428.2010.07.041This paper proposes a behavior-based detection system, which combines data mining and expert system technique to detection malware in hosts. It applies a novel sequence pattern mining method, called PrefixSpan*, which uses brief projection database in stead of projection database in PrefixSpan. PrefixSpan* algorithm mines association rules in the malware behavior sequence database, to form malware behavior pattern database, the expert system matches facts and rules and gives the final result. Experimental results show that the algorithm is correct and efficient.
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Computer Engineering. 2010, 36(7): 122-125,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.042This paper analyses the trust evaluation process based on Bayesian approach, aiming at the deficiency that it can’t reflect some important attribute of trust evaluation preferably. It improves its trust updating process, boosts up its haleness and validity, and proposes a trust evaluating model and secure routing framework based on the modified Bayesian approach. The paper implements a trust-based routing protocol based on AODV protocol. Simulational experiment proves the validity of the proposed scheme.
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Computer Engineering. 2010, 36(7): 126-128. https://doi.org/10.3969/j.issn.1000-3428.2010.07.043Through the research and analysis of secret sharing, it is found that all the existing secret sharing schemes have weaknesses, thus results in these schemes be not applied. Three secret sharing schemes are analyzed and the secure hole of them is pointed, through system initialization, secret part building and validating, secret acceptance building and recovery, Liufeng et al scheme(application research computers, 2008,(1)) is improved. Result shows that the improved scheme overcomes the security problem of the original scheme, and it is a safe verifiable secret sharing scheme.
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Computer Engineering. 2010, 36(7): 129-131,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.044To improve the confrontation capability of computer network, a network confrontation training simulation system is studied and implemented and its architecture and running flow are discussed. The key technologies are demonstrated, including network environment simulation, data collection, attack and defence toolkit and knowledge integration, network confrontation effectiveness evaluation and so on. Example of network confrontation drilling proves the validity of the system.
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Computer Engineering. 2010, 36(7): 132-135. https://doi.org/10.3969/j.issn.1000-3428.2010.07.045This paper presents an Attribute Based Access Control(ABAC) model HR_ABAC for hierarchical resource model which is commonly used in Internet. An access control decision mechanism is proposed and implemented for this model by using eXtensible Access Control Markup Language(XACML). It tests and analyzes this decision mechanism, and result indicates the mechanism is valid and practical.
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Computer Engineering. 2010, 36(7): 136-138,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.046This paper presents an Authenticated Key Exchange(AKE) protocol, named AKE-1. Compared with previous protocols, the proposal is more efficient and proven to be safe in newly enhanced Canetti-Krawczyk(eCK07) model under the random oracle assumption and the Computational Diffie-Hellman(CDH) assumption. It uses a technique named trapdoor test, recently proposed by Cash, Kiltz and Shoup. In addition, it presents a one-pass variant (for only one entity on line) and three-pass variant (providing key confirmation) of AKE-1 for different applications.
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Computer Engineering. 2010, 36(7): 139-141. https://doi.org/10.3969/j.issn.1000-3428.2010.07.047This paper proposes an efficient mechanism to detect and locate the program vulnerability based on the binary taint analysis and program analysis techniques. The method adopts the data flow analysis and taint analysis. The taint analysis method records the instruction which propagates the taint flag as well as the memory address it writes to. When it detects the attack, it locates the bug by searching the malicious write instruction through the memory address it records. Results of experiments show that the system can localize popular vulnerabilities successfully, and it is able to localize library function call point.
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Computer Engineering. 2010, 36(7): 142-143,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.048Thel protocol proposed by Rhee H S et al(Computer Standards & Interfaces, 2009, No.1) uses mobile equipment to replace smart card to reduce risk and cost, but it exists some demerits. Aiming at this problem, based on Chan-Cheng attack case, it points out that the protocol can not resist impersonation attack and off-line password guessing attack. In order to overcome these drawbacks, it gives the improved scheme. Experimental results show this scheme is strongly resistant to both of these attacks, which keeps the password secret and authenticating ID.
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Computer Engineering. 2010, 36(7): 144-146. https://doi.org/10.3969/j.issn.1000-3428.2010.07.049A number of obfuscation techniques are used to foil the static disassembly process by malware, in which embedding obfuscated data after call instruction is the most common style. This paper presents a detection arithmetic that can abstract the obfuscated data accurately after the call instruction. Based on improved recursive traversal disassembly arithmetic, this method can handle this style of obsfuscation in two phases. A test report is provided to prove the effect of this arithmetic.
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Computer Engineering. 2010, 36(7): 147-149. https://doi.org/10.3969/j.issn.1000-3428.2010.07.050Ignoring whether the terminals that under users’ control are safe to the Intranet or not, most of popular Network Access Control(NAC) systems only authenticate users via pairs of ID and password. Based on those, this paper makes improvement in safety policy controlling by adding authentication of safety information to isolate the unsafe terminals, making other terminals of the Intranet safer.
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Computer Engineering. 2010, 36(7): 150-152. https://doi.org/10.3969/j.issn.1000-3428.2010.07.051Information hiding is an important way of copyright maintenance. But the existed algorithms have many problems in hiding capacity, robustness, and most of these are just suitable for English documents. Aiming at those problems, a novel information hiding algorithm is presented, which is based on Chinese characters coding method in words platform. The algorithm implements text embedding by using coding-transform rules and sign bits. The algorithm is improved greatly on information hiding capacity and robustness, and is enhanced in security of secret information. Practicability is proved by theoretical analysis and experimental results.
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Computer Engineering. 2010, 36(7): 153-155,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.052Cryptanalysis on RSA algorithm method based on the complete square numbers is presented, which concludes the number field selection and arithmetic efficiency relationship of x and y that congruence for x2≡y2. Through theoretical proof and related research to its mechanism, and c that is called the characteristic of n prime factor of public key is constituted. The result shows: the efficiency of n-decomposition is high with right number field range and algorithm while c>2, and which is low because of the large number field range while c<2, so the tectonic RSA key is safe.
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Computer Engineering. 2010, 36(7): 156-158. https://doi.org/10.3969/j.issn.1000-3428.2010.07.053The research background and concepts of side channel attacks are introduced. A Right-to-Left style of Binary Representation’s realization(R-L for BR) of module exponentiation is depicted. Several shortcomings for the Simple Power Analysis(SPA) attacks are pointed out such that it is difficult for an attacker to break the power index of module exponentiation without hardware design experience, and the attacker must have the knowledge about the operational procedures of the R-L for BR. A Simple Differential Power Analysis(SDPA) attack is presented. The proposed method is more efficient than the SPA attack. Its feasibility and correctness are experimentally confirmed.
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Computer Engineering. 2010, 36(7): 159-161. https://doi.org/10.3969/j.issn.1000-3428.2010.07.054The application in real-time data encryption of Advanced Encryption Standard(AES) algorithm raises a high demand on the processing speed and the power consumption and cost for Field Programmable Gate Array(FPGA) implementation. Aiming at the case, an improved method for fast AES algorithm based on small-scale FPGA is proposed. The part of key expansion is implemented by microprocessor instead of FPGA, and the secret key is shared by both encryption and decryption module with the storage sharing technology. Experimental results show this method can promote the processing speed, save FPGA resource and reduce the chip power consumption.
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Computer Engineering. 2010, 36(7): 162-164. https://doi.org/10.3969/j.issn.1000-3428.2010.07.055A Temporarily-Spatially(TS) constrained Role-Based Delegation Model(TS_RBDM) is introduced. On the basis of RBDM0 and RDM2000, role, permission, and operation in delegation are all temporarily-spatially sensitive, which makes delegation have TS attribute, and introduces some formal definition of TS_RBDM including issues of strict/non-strict delegation, one/multiple step delegation, entire/partial delegation, and provides the foundation for applications executing the permission delegation.
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Computer Engineering. 2010, 36(7): 165-167. https://doi.org/10.3969/j.issn.1000-3428.2010.07.056This paper proposes a proxy ring signature scheme based on multilinear mapping. This scheme can prevent the original signer from generating signature for message as a proxy signer and prevent the key generation center from forging proxy ring signature by introducing several key generation centers. The signature private keys of signer are completed by several key generation centers. Performance analysis results show that the scheme is feasible and secure.
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Computer Engineering. 2010, 36(7): 168-169,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.057This paper presents a quantitative attribute fuzzy partition method based on Cross generation Heterogeneous recombination Catacly- smic mutation(CHC) genetic model. It adopts real number coding and PNX crossover operator, initializes operator renewedly by setting threshold value. Fuzzy 1-frequent item’s support degree, the coverage ratio of triangular membership functions for quantitative attribute and the overlap degree among membership functions are regarded as optimization object. It confirms automatically quantitative attribute’s fuzzy partition interval by genetic evolution. Experimental results show that the method reduces evolution time and the obtained optimal unit has better fitness degree value.
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Computer Engineering. 2010, 36(7): 170-172. https://doi.org/10.3969/j.issn.1000-3428.2010.07.058Handwritten device users are easy to forget how to write a certain Chinese character. It is necessary to provide Pinyin input method for them. This paper constructs a Pinyin word recognition system through classifier fusion style. It obtains the cutting point of Pinyin word by Hidden Markov Model(HMM) classifier, accomplishes after-recognition fusion by using recognition module for statistic characteristic, studies and improves the base line extraction method for Pinyin word. Experimental results show that this method can recognize 91.37% test samples from 17 745 ones.
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Computer Engineering. 2010, 36(7): 173-175,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.059This paper analyzes the semantic features and the similarity of Web news pages, and presents an automatic Web news extraction method with semantic features. It utilizes semantic classifier to find the seed information, and uses portion features to build information extraction rules. The F1-Value of Web news extraction can reach to 94.2% when add semantic features to classifier. The performance of F1-Value can reach to 96.9% when combine semantic classifier and portion features based information extraction method. Experimental result shows that the method can effectively improve the accuracy of Web information extraction method and cut the cost of manual labeling work.
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Computer Engineering. 2010, 36(7): 176-178. https://doi.org/10.3969/j.issn.1000-3428.2010.07.060In order to locate the global optimum of complex multimodal function, on the basis of standard Particle Swarm Optimization(PSO) algorithm, this paper proposes a two sub-swarms exchange PSO algorithm based on different behaviors. The particles are divided into two swarms in the same size. Different swarms adapt different evolution models. By using the characteristics that different evolution models have different evolution behaviors, the two sub-swarms influence and promote each other. This method can maintain diversity of population and reduce the possibility of local minimum. Simulation results of some complex functions show that the algorithm can easily find the global optimum solution.
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Computer Engineering. 2010, 36(7): 179-181,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.061This paper provides the method of human hair feature based gender classification. The details of algorithms applied to the hair attributes extraction and feature representation are mainly focused on, while the selection of parameters for the model is briefly discussed. Results on AR dataset of 1 680 subjects are reported. The comparison between identification using hair attributes and the eigenface-based recognition indicates that the hair attributes comparatively improve the average human gender classification rate by 7.5%. The best performance of 96% is achieved with the hair feature based extraction.
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Computer Engineering. 2010, 36(7): 182-184. https://doi.org/10.3969/j.issn.1000-3428.2010.07.062Aiming at the recognition problem of dynamic digit image, this paper proposes seven-segment digit recognition method based on secondary compound chain code. The first level 8-direction Freeman chain code description is carried on the thinned object image. On the basis of this, the second level 4-direction Freeman chain code description is continued. It can make the sole mapping relationship between the obtained compound code and the described seven-segment digit. Application result in a wireless gas monitoring system shows that this method has high recognition ratio and high processing efficiency.
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Computer Engineering. 2010, 36(7): 185-186,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.063For the problem of low accuracy in existing multi-class classification algorithm, based on Mahalanobis ellipsoidal learning machine for one class classification, a maximal margin ellipsoid-shaped multi-class classification algorithm is proposed, which bounds each class data using a hyper-ellipsoid and the data space is composed of several hyper-ellipsoids. Each hyper-ellipsoid encloses all samples from one class and at the same time excludes all samples from the rest class with maximal margin. In addition, the covariance matrix, i.e., the distribution information of examples from different classes is considered. Experimental results on real data sets show that the method can improve accuracy for classification.
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Computer Engineering. 2010, 36(7): 187-189. https://doi.org/10.3969/j.issn.1000-3428.2010.07.064To improve the effect of traditional Genetic Algorithm(GA) in solving Minimum Vertices Covering Problem(MVCP), based on the mechanism of ideal density model and characteristic of MVCP, the crossover operation in GA is redesigned by using the principle of Uniform Design Sampling(UDS) and combining the locale search strategy. This paper proposes a Genetic Algorithm Based on Uniform Design Sampling(UGA) and applies it to solve MVCP. Compared with Simple GA(SGA) and Good Point-set GA(GGA), the simulation results show that UGA has superiority in speed, accuracy and overcoming premature.
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Computer Engineering. 2010, 36(7): 190-192. https://doi.org/10.3969/j.issn.1000-3428.2010.07.065This paper introduces some perceptron algorithms and their variations, gives various pseudo-codes, pionts out advantage among algorithms. It gives mistake bound’s theorems of perceptrons algorithm in linearly separable and unlinearly separable situation. It studies their mistake bounds and works out their bounds. It shows their various applications in the online optimization, reinforcement learning and bandit algorithm, and discusses the open problems.
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Computer Engineering. 2010, 36(7): 193-194. https://doi.org/10.3969/j.issn.1000-3428.2010.07.066This paper proposes an algorithm which adopts Independent Component Analysis(ICA) to extract face feature and Core Vector Machines(CVM) to recognize. ICA is used to extract statistical independent feature and a good result can be received by selecting right feature numbers. CVM is used to classify the feature and it can handle large data sets more quickly. Experimental results show that the algorithm is feasible and effective for face recognition, and its accuracy is 94.38% on ORL.
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Computer Engineering. 2010, 36(7): 195-197. https://doi.org/10.3969/j.issn.1000-3428.2010.07.067Object tracking and recognition across multiple cameras requires as far as precise object area. Aiming at the adhesion problem of crowd object, this paper proposes a crowd object segmentation method based on posture model. According to the posture change rule during human movement, it constructs seven kinds of posture model with high probability. Each object position, size and posture message are obtained by model matching for single and combined objects. Experimental results show that this method can solve object segmentation effectively under the situation of occlusion.
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Computer Engineering. 2010, 36(7): 198-199,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.068This paper uses Informative Vector Machine(IVM) algorithm to classify the firing rates from small populations of neurons in primary motor cortex. It uses the output of classifier to recursively infer neural state and hand kinematics conditioned on neural firing rates. Experiments are done to compare IVM with Support Vector Machine(SVM) and Relevance Vector Machine(RVM), and the results demonstrate that the classification and decoding performance of neural activity of IVM is best, and its run time is least.
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Computer Engineering. 2010, 36(7): 200-202. https://doi.org/10.3969/j.issn.1000-3428.2010.07.069By combining Orthogonal Locality Preserving Projection(OLPP) and Informative Vector Machine(IVM), this paper proposes OLPP-IVM algorithm for face recognition. It uses OLPP to extract the feature of face image and reduces the dimension of data, and uses IVM to classify the face. By compared with PCA, LDA and other algorithms, the algorithm is proved to have lower error rate in face image recognition, and its performance is superior.
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Computer Engineering. 2010, 36(7): 203-204,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.070Aiming at the shortage of Support Vector Machine(SVM) slow practice speed in the case of large sample, this paper introduces weighted optimal position strategy to improve Quantum Particle Swarm Optimization(QPSO) algorithm, processes coding for voice parameters by improving Michigan coding scheme, and constructs new classified rule fitness function to realize designing of classifier based on weighted quantum particle swarm. Application results of speaker recognition show that this classifier has better performance of noise proof and recognition speed.
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Computer Engineering. 2010, 36(7): 205-207. https://doi.org/10.3969/j.issn.1000-3428.2010.07.071Aiming at the problem that searching precision of Particle Swarm Optimization(PSO) is low and optimized performance is not well for high-dimension function, this paper proposes an improved PSO algorithm. The algorithm uses an orderliness increasing mode to set particle free, enhances the useful population information, leads extreme change through release particle to strengthen computational efficiency of algorithm. Experimental results show that improved algorithm has more powerful optimizing ability and higher optimizing precision compared with other algorithms.
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Computer Engineering. 2010, 36(7): 208-210. https://doi.org/10.3969/j.issn.1000-3428.2010.07.072Aiming at the problem that recognition rate is low when using Mel-Frequency Cepstral Coefficient(MFCC) to present the abnormal sounds, this paper proposes an improved feature extraction method to handle the issue, including the analysis of the characteristics of abnormal sounds and the redesign of the filter bank of MFCC. Experimental results conducted on the database of public abnormal sounds show that the method substantially outperforms MFCC feature extraction method in recognition rate and efficiency, and it can be applied in practice.
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Computer Engineering. 2010, 36(7): 211-213. https://doi.org/10.3969/j.issn.1000-3428.2010.07.073Aiming at the problem that location precision of existing subpixel edge location algorithm is not high, based on computer simulation and common physical experiments, this paper compares edge precision and ability of noise canceling for three kinds of representative sub-pixel location algorithm such as 1D gray moment method, Gauss fitting method and polynomial interpolating method. Experimental result shows that edge locating repeatability is stable of three kinds of algorithms when SNR is beyond or equal 40 dB, error of edge locating repeatability is lower than 0.01 pixel.
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Computer Engineering. 2010, 36(7): 214-216. https://doi.org/10.3969/j.issn.1000-3428.2010.07.074In order to enhance image scaling quality, this paper proposes a self-adaptive image scaling algorithm. When pixel point of original image is in the edge area, the interpretation is carried adaptively along the edge direction obtained by Sobel operator. For the non-edge area, it uses bilinear interpolation algorithm. Experimental result shows that Sobel operator can get the edge characteristics efficiently, and this algorithm can get high-quality scaled images with lower complexity.
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Computer Engineering. 2010, 36(7): 217-219. https://doi.org/10.3969/j.issn.1000-3428.2010.07.075Aiming at current feature extraction problems in medical image, a cerebral tumor extraction method based on graph-cuts is proposed. In order to overcome the defects that graph-cuts is only oriented to small image and easily lead to a small cut-set, a clustering is applied to image to improve the accuracy and speed of feature extraction and then build the Gomory-Hu cuts tree of image. Subgraph of clustering image can be got by removing the edges of Gomory-Hu cuts tree for the value of cuts, and the sub-image can be obtained after the subgraph is mapped to original image. This method is applied to tumor extraction of MRI cerebral image. Experimental result shows that the method can precisely extract tumor of cerebral image.
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Computer Engineering. 2010, 36(7): 220-223. https://doi.org/10.3969/j.issn.1000-3428.2010.07.076Existing 2D non-local mean noise reduction algorithm can only suppress the noise inside the slice, it can not access the noise between slices. Aiming at this problem, this paper analyzes image self-similarity which is generated by Printed Circuit Board(PCB) in Cone Beam Computed Tomography(CBCT), extends existing 2D algorithm to 3D space, and proposes 3D non-local mean noise reduction algorithm based on partitioning processing. Experimental results show that this algorithm can further restrain noise, and it has higher computational efficiency.
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Computer Engineering. 2010, 36(7): 224-226. https://doi.org/10.3969/j.issn.1000-3428.2010.07.077Aimed to identify the Color Filter Array(CFA) and interpolation algorithm in cameras, a joint identification method is presented. The approximately model of interpolation is established, under this model, the iterative error and Wiener solution from incremental Wiener filtering is exploited for joint estimation of color filtering pattern and interpolation coefficients, which is identified depending on the estimated interpolation coefficients. The performance of proposed method is analyzed from the statistical data. Experimental results show the efficiency of this method.
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Computer Engineering. 2010, 36(7): 227-229. https://doi.org/10.3969/j.issn.1000-3428.2010.07.078This paper proposes an efficient graph-based approach for video copy detection. It converts the video sequence matching results to a matching results graph, so the problem of video copy detection becomes a problem of finding the longest path in the matching results graph. Experimental results show that the graph-based video sequence matching algorithm has many advantages, such as high copy locating accuracy, making up for inadequate description of image low-level features, saving detecting time, batch detecting the more than one copy which exist in two video sequences and so on.
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Computer Engineering. 2010, 36(7): 230-232. https://doi.org/10.3969/j.issn.1000-3428.2010.07.079According to the fact that motion region detected by commonly adopted frame difference has bad noise resistance ability, and cavity exits, this paper proposes the method of 3D Orthogonal Gassian-Hermite Moments(3DOGHM) for detecting moving objects based on level set segementation. This method uses 3DOGHM separate motion region and background, and adopts an improved level set segmentation motion object. Experimental results show that this algorithm has strong anti-interference ability and can detect motion object much completely and the problem of existing cavity is improved greatly.
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Computer Engineering. 2010, 36(7): 233-235,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.080To decrease the computation and the motion estimation time in a H.264/AVC coding converter, this paper presents a new improved small diamond search algorithm, which is based on the Detection of All-Zero(DAZ). In the matching computation of the search center and its near four points, DAZ is used to increase the searching rate. The method is compared with several other typical motion search methods. Keeping with certain Peak Signal to Noise Ratio(PSNR) performance, the improved small diamond search method decreases the searching points and shortens the coding time obviously. The improved small diamond search method fits for the video sequence in a stationary or middle-small motion-intensity background and the application result is good.
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Computer Engineering. 2010, 36(7): 236-238. https://doi.org/10.3969/j.issn.1000-3428.2010.07.081This paper proposes a spatial-adaptive search algorithm, and combines it with Unsymmetrical Multi-resolution Hexagon(UMH) search algorithm in H.264 to predict the motion trend of present block. Experimental results show that the algorithm can decrease 9% motion estimation time and 13% search points without losing PSNR and bit rate, compared with UMH algorithm. The computational complexity of motion estimation is reduced evidently and real-time characteristic is strengthened.
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Computer Engineering. 2010, 36(7): 239-241. https://doi.org/10.3969/j.issn.1000-3428.2010.07.082This paper produces the fingerprint by combining both the image feature based on the improved Harris detection and the motion feature based on the differences between the adjacent video frames, and retrieval video segment through similarity match of the video fingerprint. The corner descriptor of the DC image is generated based on the improved Harris method. Moreover, the motion feature is extracted by trimming the image edge of the video. The fusion factor which combines the similarity of image feature and motion feature is constructed to calculate the similarity between the candidate videos and original videos. Compared with existing method, the method proposed in this paper retrieves video segment accuracy and meets the requirements of real-time.
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Computer Engineering. 2010, 36(7): 242-245. https://doi.org/10.3969/j.issn.1000-3428.2010.07.083How to schedule equipment repair is essential for the repair decision-making. Because of the great performance of Wasp Colony Algorithm(WCA) in job-scheduling especially in dynamic and stochatic job-scheduling, this paper uses the WCA to research problem of the repair scheduling. Results from the simulation instance show that WCA is of great advantage for dynamic and stochastic jobs.
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Computer Engineering. 2010, 36(7): 246-248,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.084A class preprocessor for 32 bit embedded real-time Java platform is designed and implemented. It converts the standard class file into an image which can be executed by the real-time Java processor called Jpor-32. Operations that impact real-time performance such as classes’ loading and resolving are pre-processed by this preprocessor. As a result, it reduces the complexity of the real-time Java processor.
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Computer Engineering. 2010, 36(7): 249-251. https://doi.org/10.3969/j.issn.1000-3428.2010.07.085This paper analyses the feasibility of the hyperblock-level prediction in hyperblock-based aggressive execution model, puts forward a multi-exit predictor which adapts to hyperblock-based execution model. It demonstrates the feasibility and prediction-depth of hyperblock-level prediction based on this model. Experimental results show that a lot of applications have a higher expected prediction-depth, suitable for aggressive execution, but they have great difference in different applications.
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Computer Engineering. 2010, 36(7): 252-254. https://doi.org/10.3969/j.issn.1000-3428.2010.07.086The capacitated dynamic(time-dependent) networks are more realistic than the classical static networks, and are applicated to a wide range of fields including transportation, logistics and telecommunication network systems. Based on the shortest path algorithm in time-dependent networks, this paper studies the min max-time flow problem in capacitated dynamic networks with real background, and presents an algorithm to solve this problem. The running time complexity of this algorithm is in O(mMn).
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Computer Engineering. 2010, 36(7): 255-256,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.087The expert profile of an individual is a record of the types and areas of skills of that individual and a description of his collaboration network. This paper gives a social profile algorithm of finding experts. It defines the task of automatically determining an expert profile from a heterogeneous corpus made up of a large organization’s intranet, proposes multiple models for addressing the profiling task, and applies them to TRCKMS. An experiment based on the W3C-corpus shows a significant improvement on the efficiency of finding experts.
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Computer Engineering. 2010, 36(7): 257-259. https://doi.org/10.3969/j.issn.1000-3428.2010.07.088If the Freetype libraries are used in the embedded high-definition movie player, the srt subtitle has a problem of lag. This paper presents a method to realize the TrueType fonts drive, establishes the local indexes for the fonts, and puts all the necessary data of TrueType fonts file into memory to found the glyf memory fonts database. Test shows that the developed drive is stable and reliable and is ideal for the resource-constrained embedded platform.
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Computer Engineering. 2010, 36(7): 260-261,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.089Dual method is presented for small optic flow computation based on variational models. Robust estimation form of L1 norm is used in data terms and the regularized terms use total variation of optic flows with edge preserving property. The dual variables for total variation terms avoid using small regularized parameters in classic total variation terms and get good results. This method can be extended to computation of large displacement optical flow and higher order models.
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Computer Engineering. 2010, 36(7): 262-264. https://doi.org/10.3969/j.issn.1000-3428.2010.07.090For the complexity of Web service composition language and the composition procedure, this paper proposes a framework which can composite Web services rapidly based on Business Process Execution Language(BPEL). The framework represents the service composition logic by Directed Acyclic Graph(DAG), and resolves the DAG to generate all the documents needed automatically. Experimental result on the prototype system demonstrates that the framework archives the target of compositing Web services rapidly by concealing the complexity of BPEL.
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Computer Engineering. 2010, 36(7): 265-267. https://doi.org/10.3969/j.issn.1000-3428.2010.07.091Aiming at the production scheduling problem of Make To Order(MTO) garment enterprise in the upper and down streams, this paper proposes a method to divide supply chain role through concentrated supply chain management. It analyzes the order-driven craftwork process and establishes a coordinating production scheduling model fronting the core enterprise. The essences of problem solving are suitable order model and producer model. Considering the importance of order and producer selection according to certain condition, Genetic Algorithm(GA) implements the faster and suitable solution.
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Computer Engineering. 2010, 36(7): 268-269,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.092This paper describes the delineative characteristics of vehicle track, analyzes the advantages and disadvantages of point-by-point judgment method and combined judgment method, and presents the method of using turning point judgment to delineate the track. Analysis on measured data shows that it is feasible to simplify the location data with turning point, meanwhile combined judgment method is more accurate than point-by-point judgment method, and it has higher compression ratio.
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Computer Engineering. 2010, 36(7): 270-272. https://doi.org/10.3969/j.issn.1000-3428.2010.07.093This paper proposes a Single-Carrier Frequency-Domain Equalizer(SC-FDE) system based on Turbo channel coding, and performance under the circumstance of the Rayleigh fading channel is analyzed. Moreover, comparisons among different decoding and different iteration times are given for the higher Bits Error Rate(BER) of the traditional SC-FDE system in the complex multipath channel. Simulation results show that the BER of SC-FDE system based on Turbo channel encoding can be reduced five orders of magnitude in comparison with SC-FDE without channel coding system, and BER of the proposed system can be reduced to with a 10 dB signal to noise ratio. The reliability of SC-FDE system is enhanced. Hence, it is expected that the system can merge into the future high-speed and high-performance communications.
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Computer Engineering. 2010, 36(7): 273-275,. https://doi.org/10.3969/j.issn.1000-3428.2010.07.094According to the fact that the resources utilization is low in the grid, moreover, single point expiration and performance bottleneck problems are caused by sole and the centralized resources monitoring, etc, this paper introduces an educational resources grid architecture model and gives a resource monitoring mechanism. This mechanism employs the thought of hierarchical and distributed management according to domain which fuses the technologies of Java Native Interface(JNI), Web services and directory services. Through the construction of its overall frame and the logical organization, it shows the monitoring management process of the resources long-distance registration, the discovery and the resources point examination which can join/leave dynamically. The performance analysis indicates that the mechanism is safe, reliable and effective. It can meet the application demand of the educational resources grid.
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Computer Engineering. 2010, 36(7): 276-278. https://doi.org/10.3969/j.issn.1000-3428.2010.07.095An approach of Constraint Satisfaction Problems(CSP)-based emergency decision-making, which produces the emergency plan in order to dispose an emergency event rapidly and exactly in the process of emergency decision-making, is proposed. This approach exploits an emergency preplan to build an emergency decision-making model in which the variables denote the objects and the constraints denote rules respectively. The result of the corresponding CSP that satisfies the constraint conditions is an emergency plan. An experiment with national earthquake emergency preplan is employed as an experiment to analyze and validate this approach of CSP-based emergency decision-making.
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Computer Engineering. 2010, 36(7): 279-281. https://doi.org/10.3969/j.issn.1000-3428.2010.07.096This paper discusses the principle of wavelet packet transform threshold de-noising used for restraining noise in nonstationary signal and puts forward a method of using 3σ-rule and µ-threshold method based on wavelet packet transform to pre-process the heart sounds. The method retains the advantages of normal wavelet packet transform in signal processing, and projects heart sounds’ features. Experimental results show that the method has a significant advantage on de-noising and heart murmurs processing, and it has a very good application foreground in heart sounds detection.
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Computer Engineering. 2010, 36(7): 282-284. https://doi.org/10.3969/j.issn.1000-3428.2010.07.097Aiming at the problems of the existing service selections, such as only computing trust values under the condition of trust and distrust, and computation complexity, in virtue of transforming model between qualitative concepts and their quantitative expressions, this paper puts forward service selection based on cloud theory trust model, and presents the method of trust cloud computing, evaluation and updating. This model can express the uncertainty of trust well. It improves the average of network trust density and the cooperation success probability, and reduces network deceive effectively.
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Computer Engineering. 2010, 36(7): 285-287. https://doi.org/10.3969/j.issn.1000-3428.2010.07.098This paper analyzes the typical elements of the near-earth space, defines elements and its property included by the space scene visualization. Integrating with the characteristic and mode of the space scene expression, the visualization method and flow of the typical elements of the near-earth space, including the space environment, the space entity and its motion, are introduced. Some visualization graphs are given through experiments based on OpenGL.
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Computer Engineering. 2010, 36(7): 288-290. https://doi.org/10.3969/j.issn.1000-3428.2010.07.099To make an optimal and practical coordinate production planning under the environment of networked manufacturing, a production task decomposition and distribution model, which is based on product information and the idea of collaborative manufacturer, is put forward. The model generates the whole distribution program of manufacturing task with the order as input, by appropriate tactic of collaboration partner selection and distribution. Through the model, the reasonable, efficient and optimal decomposition and distribution can be implemented.
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Computer Engineering. 2010, 36(7): 291-封三. https://doi.org/10.3969/j.issn.1000-3428.2010.07.100This paper designs and implements a multimedia network classroom monitoring system. Controller running on teacher computer generates legal process list periodically and broadcasts it to the network. The agent running on the students computer kills all non teaching related processes through processes compare algorithm. It creates special threads to monitor the network connection, so that it can be capable of classroom management and offline control. The solution is implemented and applied in the teaching practice. It is proved from both theory and practice that it is scientific, reliable and practical.
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