20 January 2009, Volume 35 Issue 2
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Computer Engineering. 2009, 35(2): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2009.02.001Register rotation feature provided by IA-64 makes the software-pipelined loops difficult to understand, debug and migrate to other hardware plats. Based on studying the register rotation mechanism, this paper presents a method for reverse analyzing rotated register. Through dividing the software-pipelined loops into different stages and computing the rotated interval, it can identify the rotated-related registers. The method is applied to a static binary translation system I2A. The experimental results demonstrate that the proposed method is effective to eliminate the effect of register rotation on binary translation.
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Computer Engineering. 2009, 35(2): 4-5,9. https://doi.org/10.3969/j.issn.1000-3428.2009.02.002There are vastly routes in Border Gateway Protocol(BGP) router located in the Default-Free Zone. Many developers adopt Path Compressed Tree(PCT) to store the BGP routes. It is found that the performance of PCT algorithm is not so good. The lookup time fluctuates and the store memory is wasted. The performances of PCT are mostly influenced by the character of data source. In order to solve those problems, AVL algorithm is introduced. Comparison results of these two algorithms manifest that the AVL algorithm can improve the lookup performance.
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Computer Engineering. 2009, 35(2): 6-9. https://doi.org/10.3969/j.issn.1000-3428.2009.02.003There is performance bottleneck while using the traditional TCP protocol in the modern high-speed network. Based on NS-2, by changing the bottleneck bandwidth, Round Trip Delay(RTT) and parallel TCP number, all TCP variants are simulated, and their performance on the aspects of throughput, delay and packet loss rate is compared. The result indicates that most TCP variants display better performance than the traditional TCP protocol on some aspects. Among them, XCP and VCP, which adopt the explicit congestion feedback solution, have the best performance.
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Computer Engineering. 2009, 35(2): 10-11,1. https://doi.org/10.3969/j.issn.1000-3428.2009.02.004When the point pattern matching problem is resolved with spectral method, one of the challenges which limit the method is that it is very sensitive to the measurement noise of the points’ position. This paper improves the robustness of the spectral method from three aspects. It adopts the proximity matrix which takes the Gaussian weighted Euclidean distances between any two points within the same point pattern as its elements. A new sign correction method is proposed. The matching metric derived from the spectral method is further weighted by the points’ attribute information. Simulation experiments show that when the improved spectral method is applied to the point pattern matching problem on noisy conditions it can achieve a high correct matching ratio.
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Computer Engineering. 2009, 35(2): 13-14,2. https://doi.org/10.3969/j.issn.1000-3428.2009.02.005Inductive logic programming is a new method for data mining, which is based on the first-order logic. The first-order rule mining is the complicated combination optimal problem of atoms constructed by target predicate and background predicates. This paper proposes the bit-string encoding of first-order rule based on the Occam’s razor principle, designs the corresponding genetic operators, and presents the algorithm of Genetic Inductive Logic Programming(GILP) based on the sequential covering strategy and adopts genetic algorithm as the search method. It validates the feasibility of GILP algorithm through the connectivity of graphic and gcd problem.
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Computer Engineering. 2009, 35(2): 15-17. https://doi.org/10.3969/j.issn.1000-3428.2009.02.006Malware writers make use of exception return of subroutine to evade detecting by malware detectors. To crack the technique, this paper proposes a novel disassembly algorithm. This algorithm decodes an executable file twice and emulates the operations on memory stack. Through this twice-decoding and emulation process, this algorithm can be used to recognize exception returns and thus ensure the correctness of a decoding process. Compared with two commonly used disassemblers IDAPro and OBJDump, this algorithm is better at identifying this kind of exception and improves the rate of disassembly.
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Computer Engineering. 2009, 35(2): 18-20. https://doi.org/10.3969/j.issn.1000-3428.2009.02.007The TPC-H benchmark test is applied to contrast difference of select performance between database systems. Results of TPC-H test have become important standard evaluating performance of DBMSs and database servers. From the point of view of a user, a TPCHDriver of automatic software test tools are developed, designed with object-oriented modeling, programmed in Java. Test process from a load test to a power test and a throughput test, building a test result report are automatically implemented. This paper depicts test model of TPC-H benchmark, TPCHDriver’s structure and primary functions, emphases the pivotal technology of implementing a TPCHDriver.
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Computer Engineering. 2009, 35(2): 21-23. https://doi.org/10.3969/j.issn.1000-3428.2009.02.008The state-chart of Unified Modeling Language(UML) is used to describe all the possible states and the transmisson conditions of states when the events occurre to analyze the system dynamically. This paper proposes refinement Calculus of Object Systems(rCOS) based on Unifying Theories of Programming(UTP) to specify the formal semantic of UML state-chart, which overcomes the limitation in the semantic research. And it provides the consistency checking with class diagram and sequence diagram, and gives the possibility of MDA development.
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Computer Engineering. 2009, 35(2): 24-26. https://doi.org/10.3969/j.issn.1000-3428.2009.02.009This paper analyzes and implements the anti-collision algorithm of EPC Class-1 Gen-2 protocol for the problem of signal collision. It presents an improved algorithm of it. The improved algorithm does not parry the collided slots, which can reduce the probability of collision caused by random slot choice. The results of the experiment show that the improved algorithm, compared with the original algorithm, has less communications and better throughout. So the improved algorithm is a feasible and efficient solution to identify EPC Class-1 Gen-2 tags.
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Computer Engineering. 2009, 35(2): 27-29. https://doi.org/10.3969/j.issn.1000-3428.2009.02.010During the development of the 4-degree of freedom parallel tracking platform, the key software technology of which is studied. The following things are introduced: the method of compiling Matlab code to emulate parameterization of the parallel tracking platform, the method of using Solidworks and ADAMS software to get the kinematics & dynamics performance parameter of the parallel tracking platform and the method of programming on the biaxial joy stick to realize the manual control of the parallel tracking platform. Experimental rusult shows that the 4-degree of freedom parallel tracking platform is of proper design, flexible movement and well manual control property.
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Computer Engineering. 2009, 35(2): 30-33. https://doi.org/10.3969/j.issn.1000-3428.2009.02.011This paper analyzes the deficiencies of existing classifications of software errors, and presents a relatively perfect classification of code errors basing on the experiences of aerospace program software inspection and existing classifications of software errors. It applies the classification of code errors in an aerospace program software inspection. The number of detected code errors is up to 75% of all errors, and the types of detected errors can be covered by the types of code errors presented in this paper. The results of verification show that this classification of code errors can guide the code inspection effectively.
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Computer Engineering. 2009, 35(2): 34-36. https://doi.org/10.3969/j.issn.1000-3428.2009.02.012This paper proposes a load balancing model named Pipeline Load Balancing(PLB), to address the load balancing problem among concurrent modules in a parallel crawling system. Different tasks in PLB are implemented as independent modules which have similar processing abilities. Dynamic multi-threading and buffering mechanisms are employed to implement a PLB-based parallel crawler. The number of threads is adjusted according to the changing in buffer size and waiting interval of a thread. Experimental results show that the PLB-based crawler provides high performance as well as good stability.
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Computer Engineering. 2009, 35(2): 37-38,4. https://doi.org/10.3969/j.issn.1000-3428.2009.02.013By studying Apriori algorithm, this paper points out its disadvantages, and proposes the transaction database mapping for an across linker description, which reduces the time cost of the database linking and the scanning time of the transaction record. It gives an improved algorithm. By analyzing the efficiency of the Apriori algorithm and the improved algorithm, it shows that the improved algorithm is better than Apriori algorithm in execution efficiency.
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Computer Engineering. 2009, 35(2): 39-41. https://doi.org/10.3969/j.issn.1000-3428.2009.02.014Aiming at the volatility of schema evolution histories in traditional data warehouse system, this paper proposes an idea that using version metadata keeps the multidimensional schemas history. In this paper, version metadata structure has been presented. Cross-versions transparent query system and corresponding algorithms are designed. The query split algorithm decomposes the query command proposed on one schema into several sub-queries on data warehouse versions, and the integration algorithm integrates the results of sub-queries by necessary gather and transform.
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Computer Engineering. 2009, 35(2): 42-43,4. https://doi.org/10.3969/j.issn.1000-3428.2009.02.015Based on the analysis of general data exchange techniques, a technique which controls data exchange process according to specified time segment and passing instruction is proposed in order to meet the real business requirement of control precision in data exchange. The design goal, type, data structure, basic working principle and mode as well as the related process flows of time gate and passing token are discussed.
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Computer Engineering. 2009, 35(2): 44-46. https://doi.org/10.3969/j.issn.1000-3428.2009.02.016The key problem of auto-generation of virtual instrument development environment is how to congruously describe DataFlow Visual Programming Language(DFVPL)and its environment in a way independent of a particular GUI implementation. With the example of virtual instrument development environment, LabScene formally describes three most important parts: edition, execution and debugging, and translates them into C# language to realize auto-generation of virtual instrument development environment. The method is the reference of auto-generation of virtual instrument development environment which is not build on dataflow.
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Computer Engineering. 2009, 35(2): 47-48,5. https://doi.org/10.3969/j.issn.1000-3428.2009.02.017With the rapid development of Blog data, the efficiency of information retrieval in them is of great concern. Based on the analysis of the peculiar users’ needs and the special feature of Blog system, this paper proposes a new sorting algorithm on the basis of the integration of multi features like relativity, timeliness, query type, Blog writer’s interest characteristics and so on. Experimental result proves that the performance of the new algorithm is more efficient than the traditional ones.
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Computer Engineering. 2009, 35(2): 50-52. https://doi.org/10.3969/j.issn.1000-3428.2009.02.018The indexing inquiry technology of massive XML document is researched, and an XML data pagination index inquiry method is proposed, which makes the number of elements in a page as the basis for data pagination, and creates XML data pagination index. The XPath inquiry is implemented on this pagination index. Experimental results show this method can use different index inquiry ways according to different index pages, and promotes the efficiency of inquiry.
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Computer Engineering. 2009, 35(2): 53-54,5. https://doi.org/10.3969/j.issn.1000-3428.2009.02.019Aiming at the problems that BIRCH algorithm highly depends upon memory, and it is inefficient when processing new added data, a processing model of inheritable BIRCH algorithm is proposed, which uses XML technology to save clustering feature tree, and restores it by analyzing the XML document. Thus, the agility of BIRCH algorithm is strengthened, and the efficiency problem for dealing added data in it is also solved. Experimental results show this model is effective.
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Computer Engineering. 2009, 35(2): 55-57. https://doi.org/10.3969/j.issn.1000-3428.2009.02.020Data replication is a general mechanism to improve performance and availability for large-scale data-intensive applications. However, ensuring efficient and fast access to one or more replicas of desired data is a challenging problem. To solve this problem, a Prefix Matching-chord (PM-chord) algorithm which leads into chord protocol in P2P field is proposed. PM-chord takes anti-clockwise as positive, searches data by using prefix matching principle and adds the predecessor replication mechanism. Analysis and experiments show that PM-chord has good performance on replica location, is effective on hot spots question in data grids, and can achieve reliability and adaptability of implementation.
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Computer Engineering. 2009, 35(2): 58-59,6. https://doi.org/10.3969/j.issn.1000-3428.2009.02.021Aiming at the issue of lacking QoS constraints in semantic Web service discovery, this paper proposes semantic Web service discovery framework with QoS constraints. It uses a QoS verify center to guarantee the QoS information can be updated dynamically. A QoS match algorithm is provided based on the framework. Experimental results show that the framework has effectiveness and availability.
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Computer Engineering. 2009, 35(2): 60-62. https://doi.org/10.3969/j.issn.1000-3428.2009.02.022This paper studies association mining algorithm for privacy preserving on horizontally distributed datasets. Existing algorithms need scan the datasets many times, a new algorithm based on distributed FP-tree is proposed which requires only 2 scans of the datasets. It can lower the traffic effectively and protect the original data while pledging nicety.
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Computer Engineering. 2009, 35(2): 63-64,6. https://doi.org/10.3969/j.issn.1000-3428.2009.02.023In order to update the batch data, a novel clustering algorithm based on DBSCAN is proposed, which determines the relation between the original object and increment object by scanning the original one. Thus, a relevant object set is got, according to which the new clustering result is obtained combined with increment object. Experimental results show this algorithm is equal to DBSCAN, and can solve the increment clustering problem when the batch data is updated effectively.
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Computer Engineering. 2009, 35(2): 65-67. https://doi.org/10.3969/j.issn.1000-3428.2009.02.024The representation of Web application pattern gains a considerable momentum with the rapid development of the Internet and Web application. Unfortunately, as Web services are often autonomous and heterogeneous, how to composite them is a delicate and time-consuming task. This paper describes the design and realization of a framework through which existing Web services can be dynamically composed, and the composite services can be executed following a suitable sequence within a dynamic environment. This framework provides tools for specifying composite services through ontology and workflow theory. Consequently, the research efforts related to the work is a valuable attempt to increase the Web application pattern’s flexibility.
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Computer Engineering. 2009, 35(2): 68-69,7. https://doi.org/10.3969/j.issn.1000-3428.2009.02.025Bulk-loading of static R-tree index for massive spatial data is time consuming. This paper utilizes the advantage of relational database. Aiming at the Top-down Greedy-Split(TGS) algorithm, it proposes parallel bulk-loading method of static R-tree based on the storage technology of spatial data. This method accelerates the mass data bulk loading efficient, and supports the index rebuild of partition grading. Argumentation and experimental results show that the parallel built R-tree has higher query efficiency under reasonable spatial data partition.
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Computer Engineering. 2009, 35(2): 70-73. https://doi.org/10.3969/j.issn.1000-3428.2009.02.026To keep free from weak capability of express of the usage control model based on authorization predication decision(UCONA), a delegation certification model is proposed to express decision result in a fine-grained manner, and delegation certification processing statuses are defined to replace the simple access status. Decision component can make the reasonable delegation certification based on the system status when a request arrives, and also make decision to change the delegation certification processing status when the system status is changed. This method effectively avoids that the same access requests generate the delegation certification repeatedly, and the delegation certification really reflects actual demands of authorization.
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Computer Engineering. 2009, 35(2): 74-75,7. https://doi.org/10.3969/j.issn.1000-3428.2009.02.027BPEL modeling technique based on object Petri net is proposed in this paper. An approach to extend abstract BPEL processes to executable ones is also provided, which guarantees the conformance to the business protocol specified by the abstract BPEL process. BPEL2OPN is used to simulate running the resulting model.
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Computer Engineering. 2009, 35(2): 76-78. https://doi.org/10.3969/j.issn.1000-3428.2009.02.028Test case of generating scenario based on UML is very helpful for the design of test case. The method of a DHCP generating scenario test case is illustrated by using UML sequence diagram, integrate class graph and state graph. The test method based on UML sequence diagram are discussed, from finding scenario to generating test. And the environment condition of every scenario are analysed, and turn methods array, put in, put out into test case of this scenario. Result shows, test cases are few, and it reduces not only test operation amount but also repeat generating of test case.
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Computer Engineering. 2009, 35(2): 79-82. https://doi.org/10.3969/j.issn.1000-3428.2009.02.029This paper proposes an improved Chord resource routing algorithm based on opposite regions. Inheriting the simple, reliable and load balancing characteristics of Chord algorithm, the algorithm introduces routing mechanism between regions and region management mechanism which transmits the states of nodes in a region uniformly by region leader in Chord ring-like topology structure. Compared with the traditional Chord algorithm, the algorithm reduces the invalid transmitting between nodes owing to invalid routing information, decreases the average routing path, realizes selecting region leader in a region randomly and improves the efficiency of routing in opposite system.
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Computer Engineering. 2009, 35(2): 83-85. https://doi.org/10.3969/j.issn.1000-3428.2009.02.030Because result of long range dependent networks traffic Hurst exponent estimate arithmetic is not exact and loses much changed information, this paper proposes Slide Window Time Variety(SWTV) variance’s dispersion Hurst exponent estimate arithmetic, which uses Fractal Gauss Noise(FGN) list whose parameters is known and real networks traffic list BC-pAug89 collected by Bellcore to test it. The result indicates this arithmetic reduces loss of changed information, depicts Long Range Dependent(LRD) characteristic in all field, and gets well veracity and robust .
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Computer Engineering. 2009, 35(2): 86-88. https://doi.org/10.3969/j.issn.1000-3428.2009.02.031According to the characteristics and special requirements of constructing Application Level Multicast(ALM) tree, this paper proposes a new ALM algorithm based on available bandwidth measurement. Depending on the relation between the input data rate and the one-way delay, it uses multicast data as the probing source, and calculates the available bandwidth. The method helps the application reduce probing cost and influence on the network. Simulation demonstrates the effectiveness of the algorithm in terms of throughput and average link stress.
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Computer Engineering. 2009, 35(2): 89-91. https://doi.org/10.3969/j.issn.1000-3428.2009.02.032Real-time voice service is negatively influenced by the delay and jitter caused by Basic Service Set(BSS) handoff. This paper proposes a new handoff triggering mechanism with dynamic threshold, which is sensitive to signal variance while eliminating the Ping-Pong handoff effect. In order to achieve higher network performance, a fast handoff algorithm based on dynamic Cache is presented. Experimental result demonstrates that the algorithm effectively reduces handoff latency and outperforms other algorithms based on static Cache.
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Computer Engineering. 2009, 35(2): 92-95. https://doi.org/10.3969/j.issn.1000-3428.2009.02.033Topology inference is one of the main applications in network tomography, and network topology can be inferred by end-to-end measurement by using tomography. This paper discusses topology inference technologies based on network tomography, the measurement methods and topology inference methods. The measurement methods and topology inference methods are analyzed integrally, and the difficulties in topology inference are concluded. The next step researches on network topology inference are discussed.
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Computer Engineering. 2009, 35(2): 95-97. https://doi.org/10.3969/j.issn.1000-3428.2009.02.034It is a key issue to locate resources effectively in P2P network research. The routing tables of the basic Chord algorithm and the bidirectional Chord algorithm have the problems of information redundancy and regardless of peers’ heterogeneity. According to the bidirectional Chord algorithm, this paper proposes a bidirectional Chord system based on different peers by considering the heterogeneity of peers and the improvement of information redundancy in the routing tables. Experimental results indicate that the system reduces the average search top and improves the search efficiency of resources.
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Computer Engineering. 2009, 35(2): 98-99,1. https://doi.org/10.3969/j.issn.1000-3428.2009.02.035In order to deal with the distributed flow load balancing problem in multi-node systems including routers, an efficient self-adaptive algorithm is given based on feedback. Through sessions, the algorithm can get load mission groups. Based on feedback, it assigns connection missions, adjusts load parameters and attains load balancing. The key technologies are given as the fast port detection and the initialized load balancing method. Performance analysis and simulation results show the algorithm has lower system cost and better load balancing factor.
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Computer Engineering. 2009, 35(2): 100-102. https://doi.org/10.3969/j.issn.1000-3428.2009.02.036A solution based on game theory is proposed for the load balancing of mobile network Multi-homing. Through the establishment of utility function, algorithm quantifies the demand of bandwidth, establishes the Bertrand game model according to the demand of bandwidth, and calculates the Nash equilibrium price of the required bandwidth. Network distributes the bandwidth via pricing the bandwidth, so network maximizes the income for oneself. Simulation results show the effectiveness of the algorithm, which can utilize the bandwidth efficiently, and achieve the balance of load.
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Computer Engineering. 2009, 35(2): 103-104,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.037This paper proposes an adaptive judgment algorithm of available bandwidth based on theory analysis and experiments. It uses adaptive periodic probe stream to judge delay trend and get probe result feedback adaptively by sending periodic train. It can measure available bandwidth accurately and fast. Simulation result shows that the algorithm is feasible and valid, and it is an end-to-end available bandwidth measurement method with little effect on network and low measurement price.
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Computer Engineering. 2009, 35(2): 105-108. https://doi.org/10.3969/j.issn.1000-3428.2009.02.038This paper provides a range-free localization algorithm——Midnormal-based Localization Algorithm(MBLA), which is based on midnormal. This localization scheme, which belongs to range-free localization algorithm, can save the energy caused by measuring range and can achieve good localization accuracy. By theory analysis and simulation, it shows that MBLA is better than APIT algorithm in localization accuracy and communication costs.
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Computer Engineering. 2009, 35(2): 109-111,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.039This paper demonstrates the architecture, design and deployment of a distributed monitor system for Intermediate System-to- Intermediate System(IS-IS) routing protocol. By passively listening into IS-IS flooding mechanism, it adopts some algorithms to track the network topology and routing changes. The system has been successfully deployed on the test bed, where the functionality and stability are evaluated. The real-time analysis capabilities really provide the facilities for network maintenance.
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Computer Engineering. 2009, 35(2): 112-115. https://doi.org/10.3969/j.issn.1000-3428.2009.02.040In hybrid P2P network, a super peer is able to render other peers services, such as information collection and search, data relay, and NAT traverse. Due to the high dynamic characteristic of P2P network, it is difficult to design a hybrid P2P network with super peers. This paper designs a balanced, robust, self-adapted hybrid P2P network model. The focus of research work is super peer’s load balancing, robustness, self-adjusted mechanism, and failure detect and recovery. New strategies and simulation for those topics are presented.
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Computer Engineering. 2009, 35(2): 116-117,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.041The channel contention process is modeled as a dynamic game with incomplete information, and Nash Equilibrium(NE) of the game is obtained. Based on S-Medium Access Control(MAC) protocol for Wireless Sensor Networks(WSN), the IIDG-MAC protocol is proposed by using NE. Simulation results indicate that compared with S-MAC, using IIDG-MAC increases the successful transmission rate of packets, decreases energy consumption for retransmitting packets, delay and bit-drop-rate, and increases the system throughput.
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Computer Engineering. 2009, 35(2): 118-120,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.042Service oriented architecture organizes services in a provider-centric manner and discovers services in a centralized register mechanism, which brings a critical problem that more services come to being more complex and difficult the service discovery and subscription become. A two-layered agent based model for semantic service discover in P2P environment is proposed in this paper to address the problem. The model implements semantic service discovery through two-layered agent mechanism and provides QoS negotiation mechanism. Experiments indicate the model has a high recall rate and precision rate.
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Computer Engineering. 2009, 35(2): 121-122,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.043Session Initiation Protocol(SIP) can implement the control of Next Generation Network(NGN) integration service, but it can not make a difference between users and data services. In order to solve these problems, this paper presents a new Priority Qos Session Initiation Protocol (PQ_SIP) based on the SIP protocol, proves that the PQ_SIP protocol stack can reduce the resource consume of terminal, distinguish the priority of users and service, and implement the separation of call control and session control.
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Computer Engineering. 2009, 35(2): 123-125. https://doi.org/10.3969/j.issn.1000-3428.2009.02.044Timing attacks are used to collect and analyze the valuable information of algorithms from the different amounts of time, which are taken when cryptographic devices are working, and they are the most effective side channel attacks. This paper analyzes the process of the RSA decryption algorithm on the research in RSA encryption algorithm and timing attacks, illustrates the theory of timing attack to RSA bases on the modular exponentiation and the square and multiply algorithm, and discusses how to defense timing attack on RSA.
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Computer Engineering. 2009, 35(2): 126-128. https://doi.org/10.3969/j.issn.1000-3428.2009.02.045To enhance the security and efficiency in electricity data storage, Non-intrusive Add-on Steganographic(NAS) system based on New Technology File System(NTFS) is proposed, with the analysis of the access control and encryption and some existed steganographic file system. This system can be superimposed on NTFS file systems to provide concealment of user-selected files/folders with minimal changes to the underlying storage structure. Unlike current steganographic schemes, NAS requires just bare minimum modification to the file system, and is much more efficient and cost-effective.
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Computer Engineering. 2009, 35(2): 129-132. https://doi.org/10.3969/j.issn.1000-3428.2009.02.046Compliance is an important factor that decides whether TPM chip has security exploits. This paper presents a testing scheme on compliance of Trusted Platform Module(TPM) interface commands towards Trusted Computing Group(TCG) specifications, with methods on constructing testing sets with finite state machines. The prototype of the testing platform is implemented and used to test on the real TPM chips. The results show the effectiveness and feasibility of this scheme.
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Computer Engineering. 2009, 35(2): 133-135. https://doi.org/10.3969/j.issn.1000-3428.2009.02.047This paper extends the subjective logic and develops a new trust and reputation evaluation model in P2P network. Considering to the history effect, it defines the mapping relationship and function between the evidence space and the opinion space again and a definition of risk is presented. Experimental results show that the trust relationships between peers can be evaluated more precisely, and security problems exist in P2P network also can be resolved more effectively.
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Computer Engineering. 2009, 35(2): 136-138. https://doi.org/10.3969/j.issn.1000-3428.2009.02.048In migrating workflow management, identity authentication of migrating instance presents some complicated features owning to migration of migrating instance between sites continuously. Combined with certificate, this paper proposes an authentication model based on Pass and Visa, which applies mutual signature strategy by creator of migrating instance issuing Pass for it and destination issuing Visa. Based on authentication mechanism of migrating instance with Pass and Visa, the destination can recognize the identity of migrating instance efficiently and endow some permission with it. The owner of migrating instance can trace the history path based on Visa certificate chain.
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Computer Engineering. 2009, 35(2): 139-141. https://doi.org/10.3969/j.issn.1000-3428.2009.02.049Network covert channels poses a serious threat to the security of computer network for they can be used to bypass the firewalls or other forms of security systems. This paper analyzes the principle of the network covert channels and presents several means to set up network covert channels, and proposes two new methods to construct covert channel: a method based on the data packets’ length and another method based on the data packets’ arrival sequence. A few key issues on building network covert channel are discussed.
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Computer Engineering. 2009, 35(2): 142-144. https://doi.org/10.3969/j.issn.1000-3428.2009.02.050A fast disk encryption algorithm targeted at the specific application scenario of disk encryption is devised. The new algorithm is a tweakable cipher, and experimental results show that its performance is about 20% better than the algorithm adopted by Windows Vista Bitlocker Driver Encryption in software environment. The algorithm can provide the pseudo integrity protection ability.
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Computer Engineering. 2009, 35(2): 145-147. https://doi.org/10.3969/j.issn.1000-3428.2009.02.051This paper proposes an improved Statistical Hitting Set attack(SHS-attack) based on MIX anonymity technique and a defence strategy based on dummy packets to counter against this attack. Theoretical analysis and simulations show that, this attack is more efficient than previous SHS-attack while all the recipients congregate in a small group and the dummy packet technique can effectively decrease the accuracy of this attack.
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Computer Engineering. 2009, 35(2): 148-150. https://doi.org/10.3969/j.issn.1000-3428.2009.02.052Aiming at the fact that Xwodi, a kind of Trojan software, is fit in the users handsets by downloading software and threatens the privacy of user deadly. With analyzing security fault and cause in the solution of current software download. This paper puts forward the control policy for mobile equipment for downloading software, sets up politic model, carries out formalized description and analysis, designs implementing scheme of software loading policy from point of view of trusted mobile platform and makes security analysis for the model. Result indicates that the scheme can prevent Xwodi from being intruded effectively.
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Computer Engineering. 2009, 35(2): 151-153. https://doi.org/10.3969/j.issn.1000-3428.2009.02.053This paper describes security audit event in the form of Unified Modeling Language(UML) with the idea of object oriented theory, and proposes security audit event visualization model based on the theory of colored Petri-net. Based on this model, with the file operation audit events, it gives a visualization method for time and space logic correlation of security audit event. The method provides convenience and assistant of browsing and analyzing audit data for security auditor.
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Computer Engineering. 2009, 35(2): 154-156. https://doi.org/10.3969/j.issn.1000-3428.2009.02.054Microdata publication need satisfy the basic K-anonymity requirement as well as improve the precision of anonymized data. This paper proposes two related K-anonymity algorithms based on the notion of multi-dimensional generalization path, namely K-anonymity Filter algorithm and K-anonymity partial Filter algorithm. In comparison with classic Datafly algorithm and Incognito algorithm, the two algorithms offer more efficiency for both reducing anonymization cost and improving data precision.
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Computer Engineering. 2009, 35(2): 157-158,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.055Privacy preserving is an important direction for data mining research. This paper concentrates on the issue of protecting the underlying attribute values when sharing data for clustering and proposes a method called Discrete Cosine-Based Transformation(DCBT), random selects the k attributes and then distorts them with discrete cosine transformation. In the process of transformation, the goal is to find the proper chain of transform to satisfy the optimum privacy preserving requirement. For the centralized data, the experiments demonstrate that the method efficiently distorts attribute values, preserves privacy information and guarantees valid clustering results.
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Computer Engineering. 2009, 35(2): 159-161. https://doi.org/10.3969/j.issn.1000-3428.2009.02.056Aiming at security and privacy of Radio Frequency Identification(RFID), a discrete sequence of tag ID-based authentication protocol for RFID-DSTAP is proposed. This paper uses it to compare with other authentication protocols and analyzes it with BAN logic. Result of analysis shows that DSTAP meets the specified safety design requirements and the calculation is greatly reduced.
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Computer Engineering. 2009, 35(2): 162-163,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.057Most Session Initial Protocol(SIP) authentication schemes only provids client-to-server authentication, and HTTP Digest authentication is one of them. This paper analyzes the procedure and security of HTTP Digest authentication, and describes the vulnerability and possible attacks to the protocol. According to the vulnerability and possible attacks, it presents an improved scheme, which achieves secure transfer of message, and analyzes its security.
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Computer Engineering. 2009, 35(2): 164-166. https://doi.org/10.3969/j.issn.1000-3428.2009.02.058According to set theory, the method specifies the firewall filtering rules and various types of anomaly among them, brings forward a judgment method of anomaly types, points out the problems in the process of judgment which works directly on firewall rules. On the basis of order-sensitive characteristic of firewall rule configuration, the method finds out the equivalent irrelevance-rule set and modifies the filtering rule.
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Computer Engineering. 2009, 35(2): 167-167,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.059Recent research pays more attention on trust establishment in one securing region, there are some shortages to establish trust for the strangers in the virtual computing environment. Therefore this paper proposes a game model for trust establishment based on the game theory. It finds the coarse set of exchange credential which is generated according to local access control policies, and uses Nash Equilibrium(NE) to refine the set of exchange credential, so as to make the client and server gain the most trust but loss the least privacy. And exchanges the refined set of exchange credential at one time to save the communication time which is brought by exchange credentials time without number according to the access control policies. The game model for trust establishing not only resolves the problem of establish trust between strangers, but also improves the efficiency of trust establishment.
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Computer Engineering. 2009, 35(2): 170-171,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.060Proxy signcryption is useful when an original signcrypter needs to delegate his or her signcrypting capability to a proxy signcrypter, and the proxy signcrypter can signcrypt messages on behalf of the original signcrypter. This paper proposes an identity-based proxy signcryption scheme from bilinear pairings. Analysis shows that the scheme is secure, assuming that BDH problem and DBDH problem are hard. It satisfies all the security that a strong proxy signcryption scheme requires. Compared with other schemes, the scheme is proved more efficient and suitable for many applications.
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Computer Engineering. 2009, 35(2): 172-174,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.061Intrusion prevention system is a new information security technology which can supply a gap of the firewall and the intrusion detection system in the information security domain. As work in-line, IPS faces with many challenges, such as bottleneck of data detection, false negative and false positive. This paper proposes a new way trying to solve these problem, which is called Adaptive Intrusion Prevention System co-stimulated by Danger Signal(DSAIPS). Experiments show the primary effects.
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Computer Engineering. 2009, 35(2): 175-176,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.062Forward security and public revokability are two important properties of a group signature scheme, which can mitigate the damage caused by key exposure and keep secure member revocation. This paper puts forward the realization of the two properties in generalized group signature and designs an efficient and generalized group signature realizing any access structure can sign on behalf of the group.
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Computer Engineering. 2009, 35(2): 177-179. https://doi.org/10.3969/j.issn.1000-3428.2009.02.063Human gait recognition is the process of identifying individuals by their walking manners. The gait as one of biometrics has recently drawn attention to the computer vision researchers. The stance estimation of one’s each gait sequence is based on the dynamic programming-based Viterbi algorithm, which returns a sample stance sequence. The corresponding stances of sample stance sequences are averaged to get his feature stance sequence. Principal component analysis and linear discriminant analysis are used for feature transformation of feature stances in the feature stance sequence. The recognition is achieved by nearest neighbor algorithm. The experiments made on CASIA gait databases obtain comparatively high correction identification ratio and comparatively strong robustness for variety of bodily form.
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Computer Engineering. 2009, 35(2): 180-183. https://doi.org/10.3969/j.issn.1000-3428.2009.02.064Traditional Support Vector Machine(SVM) is originally designed for binary classification. How to effectively extend it to multi-class classification is still an on-going research issue. After analysis and comparison of the problems and defections of the existing One-Versus-One(OVO) methods of multi-class SVMs, the novel multi-class classification method based on probability voting strategy is put forward. In the new strategy, the differences and different weights among these two-class SVM classifiers are considered and combined with the value of voting. The presented multi-class SVMs method can achieve the better classification ability and resolve the unclassifiable region problems in the conventional Max-Wins-Voting(MWV) strategy. Moreover, the multi-class SVMs method based on probability voting is used as the key technology of fault diagnosis for gearbox. The practical results show that compared with traditional MWV strategy, the presented one is effective.
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Computer Engineering. 2009, 35(2): 184-186. https://doi.org/10.3969/j.issn.1000-3428.2009.02.065Fuzzy Horn clause rules can be used to represent human knowledge in terms of natural language. However, it is more difficult to discover fuzzy Horn clause rules and its implication degree. From the logical point of view, in this paper, fuzzy Horn clause rules, support degree, implication degree and related concepts are defined. The processes of mining fuzzy Horn clause rules are analyzed, and the formal algorithm is proposed. This algorithm integrates the concepts of fuzzy Horn clause logic and the Apriori algorithm to find fuzzy Horn clause rules from quantitative databases.
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Computer Engineering. 2009, 35(2): 187-189,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.066The localization of a part’s edges and the speed of the image are important factors in detecting the size of the part with a CCD image measurement system. An integrated gradient edge detecting algorithm based on the Facet model is studied in this paper. For the low efficiency and low localization, a dynamic thresholding method is used for enhancing the precision of localization, and an accelerated method is provided for computing 2D Facet model. It reduces the computation complexity from to by decomposing the 2D convolution mask to two 1D masks. The principle of the algorithm is analyzed, and the experiments for detecting the edges of some images are finished. The images include an ideal image without noise and a practical image of a circuit board. With experimental results, it is known that the algorithm in this paper can reduce the effects of image noise availably and preferable edges are detected, and it is able to improve the speed of the computation.
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Computer Engineering. 2009, 35(2): 190-193. https://doi.org/10.3969/j.issn.1000-3428.2009.02.067While next generation wideband wireless communications network can provide the users high speed service, image or video information transmission and high speed access Internet services, it brings the new challenge for system’s handover scheme. The former handover scheme which only considers the sole factor of the system is not suitable for the next generation wideband wireless communication network. This article uses the fuzzy logic technology to carry on the select of goal cell in handover scheme. Compared with the traditional methods, the fuzzy logic technology may give attention to many kinds of factors to provide more reasonable selection result and also can balance the load of the system, reduce the reject rate of handover.
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Computer Engineering. 2009, 35(2): 194-196. https://doi.org/10.3969/j.issn.1000-3428.2009.02.068A mixed method of reducing the text features based on feature selection and feature extraction is brought forward. The characteristics about feature selection and feature extraction are analyzed. Some features are chosen by using the sort distribution information. And a new way based on Principle Component Analysis(PCA) is used to extract the surplus features and realize the compression of features twice. In the precondition of the information loss least, the text feature decrease smart is completed. Test results show that this method has a better precision in the text categorization.
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Computer Engineering. 2009, 35(2): 197-199. https://doi.org/10.3969/j.issn.1000-3428.2009.02.069The technology of pair-wise covering test with parameters is an effective way in the software test. This paper proposes a mixed algorithm with Ant Colony Optimization algorithm(ACO) and Simulated Annealing algorithm(SA) which is called ASA for short, and uses it in pair-wise test case reduction. According to the special requirements, the paper attempts to process various modeling ways, and does the research on the parameters referring to this algorithm. The ASA algorithm is verified by the experiment, which indicates that the algorithm is effective in the reduction of the test case.
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Computer Engineering. 2009, 35(2): 200-202. https://doi.org/10.3969/j.issn.1000-3428.2009.02.070One of the main aims of Ambient Intelligence(AmI) is to make human interaction with the environment more natural. The concept of natural human machine interaction in AmI is embodied through speech recognition technology. In order to ensure the real-time of the interaction, the system implements the algorithms by using IP core technology. The experimental result shows that the system performs well and it is helpful for the application research of speech recognition technology in AmI.
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Computer Engineering. 2009, 35(2): 203-205. https://doi.org/10.3969/j.issn.1000-3428.2009.02.071Aiming at the problem that the simple genetic algorithm is easy to produce premature convergence, an Adaptive Genetic Algorithm(AGA) is presented to automatically generate test data. The method of program insert is integrated with AGA to implement the automatic generating of path test data. The performance of AGA is tested by using a program of triangle classifier as an example, and experimental results show this automatic generating system of test data based on AGA can automatically change the probability of selection and probability of mutation, which promotes the efficiency of automatic generating test data.
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Computer Engineering. 2009, 35(2): 206-207,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.072Category distribution in a training set has a major effect on the quality of text categorization. Based on the study of data sets asymmetry for two types of text categorization, a feature weight adjustment method based on feedback information is proposed. In this method, in order to estimate the true influence of small categories in the training process, word weight is adjusted according to the number of correct classified and misclassified training samples. Experimental results show that the method is effective in resolving data sets asymmetry on the impact of text categorization, and the classification quality is observably improved.
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Computer Engineering. 2009, 35(2): 208-209,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.073Aiming at the problem of the higher rate of losing alarm and false alarm in traditional intrusion detection system, a novel intrusion detection system based on genetic neural network is proposed, which combines genetic algorithm with BP algorithm to optimize the initial values of weights and bias of BP network by using the characteristic of strong macro search ability and optimization in overall situation. On basis of this, the neural network study is conducted, and the optimized analysis model of intrusion detection system is set up. Experimental results show this algorithm can be applied to this intrusion detection system effectively.
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Computer Engineering. 2009, 35(2): 210-213. https://doi.org/10.3969/j.issn.1000-3428.2009.02.074Multi-view gender classification, which is based on facial images, is one of the most challenging problems for computer vision researchers. This paper proposes a novel approach, Local Gabor Binary Mapping Pattern(LGBMP), to improve the correct classification rate for multi-view gender classification. The proposed approach which combines local binary pattern histogram, spatial information and the magnitude part of Gabor filter is robust to noise and local image transformations caused by variations of illumination and pose. Experimental results on the CAS-PEAL face database show that the proposed LGBMP achieves the highest correct classification rate of 95% on all of the 9 face poses.
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Computer Engineering. 2009, 35(2): 214-215,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.075A reliable color modeling approach is proposed, through which a color statistical characteristic mathematical model based on brightness variations is set up. The features of this model contains the chroma changing with brightness, the mean of saturation, and standard deviation. The curve fitting is conducted to this model by using B-spline curve, which implements the color image segmentation. Experimental results show this algorithm has better effect of segmentation and strong rubustness, it can be applied to the color image segmentation in different lighting conditions.
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Computer Engineering. 2009, 35(2): 216-218. https://doi.org/10.3969/j.issn.1000-3428.2009.02.076This paper presents a method for estimating the orientation of a textured surface. Keypoints with scale invariant features in a texture image are detected, and the local patterns with these keypoints as centers are described by the direction and scale normalized features. The patterns are clustered by the features. Under the assumption that all the scale variation of the similar patterns is attributed to the perspective effects the surface orientation is estimated. Experimental results show that the method is simple and effective.
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Computer Engineering. 2009, 35(2): 219-221. https://doi.org/10.3969/j.issn.1000-3428.2009.02.077A method of water automatic detection for SAR images is presented, which uses tree wavelet to decompose the SAR images, obtains the medium-frequency imformation from the sample image and the test image, and analyzes the texture. The texture information of the sample image is trained by using Fuzzy Weighted Support Vector Machine(FW-SVM), and the water decision function is got, through which the water region can be detected. This method combines the gray and texture information of the SAR image, reduces the noise effect, and is suitable for the water automatic detection of large area SAR image.
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Computer Engineering. 2009, 35(2): 222-224. https://doi.org/10.3969/j.issn.1000-3428.2009.02.078For aerial image sequence, a new method is proposed to estimate the motion vectors of the image feature points, which is extracted by means of improved Minimum Intensity Change(MIC) algorithm. Adaptive Rood Pattern Search(ARPS) algorithm is applied for finding the matching points of the feature points. Combining Random Sample Consensus algorithm(RANSAC), the affine transform parameters of the background motion can be estimated, and then the background motion can be compensated. The improved background motion compensation method offers great promise in the moving target detection of aerial image sequence.
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Computer Engineering. 2009, 35(2): 225-226,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.079This paper introduces a matting model based on exemplar to realize automatical training and detection in real-world image. Combined with spatial histogram of visual words improve the performance of order less bag-of-features image representation. Background and foreground information can be got automatically from the phase of localization. It uses graph-cut technique to accomplish matting automatically. The test results on Pascal VOC2006 test set show that the detection rate of this method is high, and its automatically matting effect is as well as existing interactive image cutout tool.
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Computer Engineering. 2009, 35(2): 227-229. https://doi.org/10.3969/j.issn.1000-3428.2009.02.080Traditional image enhancement algorithms can not get ideal effect when processing the images with lots of noises and insufficient or non-symmetric light, especially for surface images of cold rolled strips on industrial site. To settle the problem, this paper proposes a wavelet-based algorithm for image enhancement and applies it to enhance strips surface defect images. Experiments show that the algorithm excels traditional ones in image enhancement effects and anti-noise capabilities.
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Computer Engineering. 2009, 35(2): 230-232. https://doi.org/10.3969/j.issn.1000-3428.2009.02.081On the basis of the user’s requirement and to the design points of the tolerant computer’s reliability, this paper introduces an embedded redundant computer’s composing and principle, puts forward the tolerant technology’s selection and application including selection of redundant and synchronization mode and design of voter, and presents the hardware’s reliable design means and the software’s design idea. Experiments approve the redundant computer’s reliability.
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Computer Engineering. 2009, 35(2): 233-235. https://doi.org/10.3969/j.issn.1000-3428.2009.02.082Aiming at the problem existed in traditional PCI bus, a scheme of serial RapidIO-PCI bridge in mode of asynchronous FIFO memory is proposed. The structure and its performance of high speed bus for RapidIO are introduced. According to the protocol of PCI and RapidIO, the key section of this bridge is designed, which is inspected and implemented. Experimental results show this scheme is effective.
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Computer Engineering. 2009, 35(2): 236-238. https://doi.org/10.3969/j.issn.1000-3428.2009.02.083This paper designs and implements an Universal Serial Bus(USB)1.1 controller. It supports control, interrupt and bulk mode at full speed. The number of the endpoints of this IP is configurable. The IP works in a security chip and it breaks some of the bottleneck of the chip I/O communications. An FPGA verification platform is built with this USB 1.1 device IP and MCU 8051, and it can communicate with the PC. Other function modules in the security chip are tested on this platform.
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Computer Engineering. 2009, 35(2): 239-241. https://doi.org/10.3969/j.issn.1000-3428.2009.02.084Considering the deficiency of the presently autonomous vehicle navigation terminal on dynamic updating of map data and reception of real-time traffic information, this paper presents the design options, which is based on the thought of combining the network with the autonomous navigation. It is accomplished by the combo vehicle navigation terminal which is based on GPRS. This paper introduces the structure and principle of S3C44B0X, GPS, General Packet Radio Service(GPRS), electrical source and other major modules, debugs the terminal and optimized the data received by GPS. The design options of hardware, while combining with software, is conducive to achieve the dynamic updating of map data, and the dynamic navigation which is based on the real-time traffic information.
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Computer Engineering. 2009, 35(2): 242-244. https://doi.org/10.3969/j.issn.1000-3428.2009.02.085This paper introduces the design of a multi-channel data collecting system based on TMS320F2812. The system uses TMS320F2812 to realize the data acquisition processing. It transforms data to PC form Universal Serial Bus(USB)2.0. The position machine analyzes the data and feeds back the result to the Digital Signal Processor(DSP) for controlling. This design is simple, realizable, flexible, high ability and low cost.
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Computer Engineering. 2009, 35(2): 245-246,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.086Taking the 1 450 mm five-stand cold tandem rolling mill as designed object, this paper uses the WinCC configurable software of Siemens Company as the design flat roof to design the second-level monitor system of this rolling mill. The system has four parts, includung the calculation of rolling schedule, human-machine interface, database and production report forms, and exit system. These parts include all the basic functions of the monitor system to the five-stand cold tandem rolling mill. The system has consummate functions and friendly interfaces, and reaches the design requests.
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Computer Engineering. 2009, 35(2): 247-249. https://doi.org/10.3969/j.issn.1000-3428.2009.02.087This paper presents a fast tag identification algorithm based on tag postfix and query-prefix to solve the zero-response problem in the process of Radio Frequency Identification(RFID) arbitration. Experimental results show that the algorithm needs less time of prefix broadcasting, tag response and the amount of information sent during the arbitration than Memoryless algorithm. So it is more efficient and shortens the time of arbitration process.
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Computer Engineering. 2009, 35(2): 250-252,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.088The traditional Client/Server(C/S) and Browser/Server(B/S) architecture have advantages and disadvantages, and double client-server architecture makes up for the deficiency of a single architecture, with strong expansibility. This paper based on the type of AE2000B process control experimental device, adopts double server software architecture with customed communication protocol and real-time curve to reach aim of remote control experiment. The results show it brings satisfactory effects.
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Computer Engineering. 2009, 35(2): 253-255. https://doi.org/10.3969/j.issn.1000-3428.2009.02.089Aiming at the problem of real-time virtual visualization of vegetation in large-scale scenes, this paper presents a method to generate distribution and attributes of individual plants at application runtime using Wang Tiles and vegetation coverage data from Geographic Information System(GIS). By utilizing geometry level-of-detail model and texture splatting, real-time rendering is achieved. Experimental results show that this method can visualize large-scale scenes with vegetation at interactive frame rate while moving through in virtual environment.
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Computer Engineering. 2009, 35(2): 256-258,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.090This paper implements a system that exhibits the combination of Chinese traditional painting art and Chinese traditional classic music instrument. It takes a piece of Chinese traditional music instrument Guqing as an input device, and a modern projector as output device to show the layout design of Chinese painting. This system applies a piece of touch pad, with which the audience can sign or repaint on the new layout painting to support recreation. It is suited for exhibiting Chinese painting in museum or art show.
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Computer Engineering. 2009, 35(2): 259-262. https://doi.org/10.3969/j.issn.1000-3428.2009.02.091This paper presents a component-oriented Mashup framework based on Grid Service Markup Language(GSML). It includes several concepts that Funnel is the encapsulation of Web resources, which provides a high-level abstraction of the access to heterogeneous Web resources, and event is the communication method among Funnels. This framework facilitates the development of Mashup applications, and end users can operate on the other sites’ Web resources with access control.
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Computer Engineering. 2009, 35(2): 263-264,. https://doi.org/10.3969/j.issn.1000-3428.2009.02.092Multi-language comprehensive information services is becoming more and more important in information services area. For the 2010 Shanghai world expo and urban information services, this paper presents a general framework of multi-language comprehensive information services system. Based on Next Generation Network(NGN) technology, the system is divided into seven layer architecture in logical structure. Through various types of portal, the system integrates multi-lingual speech recognition, text to speech, machine translation, and other key technologies, uses existing urban resources information services, and provides users convenient multi-language comprehensive information services.
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Computer Engineering. 2009, 35(2): 265-267. https://doi.org/10.3969/j.issn.1000-3428.2009.02.093In order to monitor the multi-parameter in hospital operating room, the application of GM8125 in data communication system for the information board is introduced. AT89S8252 is adopted for the main MCU. Due to realizing COM extension by using GM8125, the multi-data is expediently integrated including the data of monitor for IT power supply, the controlling parameter for air condition, the pressure parameter of gas used in hospital, the controlling parameter for upper computer. Practical results show that the method has the characteristics of the ability of controlling easy. The ability of reducing the data line and the ability of depressing system resources of the main set. When reliable data communication is accomplished, the suited time requirement of the system will be fully satisfied.
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Computer Engineering. 2009, 35(2): 268-270. https://doi.org/10.3969/j.issn.1000-3428.2009.02.094This paper presents an algorithm for large-scale terrain rendering. It splits the terrain into several patches, and uses triangle bintrees to represent terrain meshes. At run time, it updates terrain meshes by forced split and forced merge operations, which can take the advantage of frame-to-frame coherency and automatically avoid cracks. Experimental result shows that this algorithm can efficiently improve the performance of ROAM algorithm and can be used in real-time walkthroughs in large-scale terrain at high frame rates.
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Computer Engineering. 2009, 35(2): 271-273. https://doi.org/10.3969/j.issn.1000-3428.2009.02.095This paper describes the development of a prototype system using part-separation for constructing a feature human model, which is to be stored in a 3D digital mannequin database for electronic Made To Measure(eMTM). Subjects like noise filtering, key features extraction, part separation and mesh construction are introduced. In order to demonstrate the functionality of mannequins, some applications are given at the end of the paper.
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Computer Engineering. 2009, 35(2): 274-276. https://doi.org/10.3969/j.issn.1000-3428.2009.02.096In light of the issues of serious traffic congestion and urgent road safety, this paper presents a distributed intelligent transport service system based on optimization and implementation of a Vehicular Ad-hoc Network(VANET) routing protocol. It provides adjacent area dynamic traffic information, urgent traffic accident warning and information distribution of traffic images/videos. Compared with the traditional methods, VANET plays its advantages in the direct interaction between vehicles of traffic, security, entertainment etc. real-time information.
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Computer Engineering. 2009, 35(2): 277-279. https://doi.org/10.3969/j.issn.1000-3428.2009.02.097In order to accelerate the efficiency of manufacturing, new technologies such as networked manufacturing and E-business for manufacturing need to be developed. This paper builds an E-business service system for manufacturing by utilizing services-integration, which is based on the Enterprise Application Integration(EAI). The business process is created according to the real application. The business process is mapped to Business Process Execution Language(BPEL) patterns. The system Is implemented with BPEL.
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Computer Engineering. 2009, 35(2): 280-282. https://doi.org/10.3969/j.issn.1000-3428.2009.02.098In the process of enterprise’s flow coordination, in order to make enterprise’s management of business rules become more agile, prevent enterprise’s private business rules from exposed to other enterprises, and monitor the process execution, this paper integrates business rules and Web services to implement State-driven Executable Business Process Model(SEBPM). The model defines Abstract Process Flow(APF) and Extended Business Rule(EBR), concluding the coupling strategy between business rules and process flows. A case of SEBPM is presented.
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Computer Engineering. 2009, 35(2): 283-285. https://doi.org/10.3969/j.issn.1000-3428.2009.02.099Common dynamic binary translation system is lack of debugging tools or only provides primitive debugging supports, so debugging technology becomes the bottleneck of developing system software or large scale software. This paper introduces a new debugging technology on dynamic binary translation platform, including reverse executing, debugging script and other new concepts. The debugger implemented on Crossbit is proved that it reduces the time for developer to locate bugs sharply.
2024
Volume 50 No 3
Volume 50 No 3
(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