20 February 2009, Volume 35 Issue 4
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Computer Engineering. 2009, 35(4): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2009.04.001This paper presents an IP Multimedia Subsystem(IMS)-based time-shifting system architecture for mobile multimedia broadcast. The architecture integrates broadcast network and wireless mobile communications network to provide time-shifting service for mobile multimedia broadcast, which achieves access independence. The Session Initialize Protocol(SIP)-based signaling flow is applied to support time-shifting service. This paper conducts a theoretical analysis of time-shifting signaling delay based on queuing theory. The results show that the signaling delay is acceptable according to the real-time requirements and proves that the system is feasible.
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Computer Engineering. 2009, 35(4): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2009.04.002Reusing the existing IP cores to compose globally asynchronous locally synchronous system is gaining increasing importance for the upcoming system-on-chip designs. The correct interface design and synchronization issue become a crucial step for the whole development process. This paper proposes a verification technique based on modified abstract timing diagrams and predication detection method with non-classical computation slicing optimization technique for synchronization. It is very effective due to exponential gains in reducing the global state space.
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Computer Engineering. 2009, 35(4): 7-9. https://doi.org/10.3969/j.issn.1000-3428.2009.04.003This paper builds the model of data-packet loss problem in shared control system, and analyzes its affection on control system. Compensation algorithm on packet loss based on hybrid pi-sigmod fuzzy neural network is invented by using the theory of predictive compensation control. Simulation and experimental results show that this algorithm can kick off the bad influence of packet loss phenomena on control performance and stability of the control system.
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Computer Engineering. 2009, 35(4): 10-12. https://doi.org/10.3969/j.issn.1000-3428.2009.04.004Aiming at deficiencies of load-balancing technology in the existing WebGIS, the paper analyzes the necessity and feasibility of cluster technology and proposes a new distributed load-balancing model based on map server farm to improve WebGIS performance. The algorithm, named distributed dynamic load-balancing scheduling algorithm, is researched as the core component in the model. A test-bed is established. A series of test results prove that the algorithm has good global load balancing performance.
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Computer Engineering. 2009, 35(4): 13-15. https://doi.org/10.3969/j.issn.1000-3428.2009.04.005Aiming at the problems such as large quantity of computing and low processing speed for grid subdivision module in pre-processing system, the sequential grid subdivision algorithm is parallelized, which is implemented by using multi-thread parallel mechanism. This parallel algorithm is also tested. Experimental results show this algorithm has absolute advantage to sequential algorithm on processing speed, and the accelerated speed and parallel efficiency increase as grid accuracy or the number of basic entities rises.
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Computer Engineering. 2009, 35(4): 16-18. https://doi.org/10.3969/j.issn.1000-3428.2009.04.006Aiming at the problems existed in credibility evaluation about simulation system, an evaluation method for simulation credibility based on Rough Set-Fuzzy Synthesis Evaluation(RS-FSE) is presented. On the basis of introducing the theory about RS and FSE, this paper concludes the idiographic steps for credibility evaluation based on RS-FSE, and takes a simulation system as an example to test this method. A credibility evaluation model is also set up. Experimental results show this method is effective and feasible.
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Computer Engineering. 2009, 35(4): 19-22. https://doi.org/10.3969/j.issn.1000-3428.2009.04.007In order to simplify the excessive alerts of IDS, so as to reduce the number of false positives, an alert verification scheme based on active D-S theory classifier is presented in this paper. This scheme adequately reflects the probabilistic relationships of the factors which influence the verification results, and effectively resolves the problem in the traditional methods that the verification method is too strict. Additionally, the scheme has the ability to study the behavior of the attacks to enhance the veracity of the verification. DARPA 2000 LLDOS1.0 from MIT Lincoln Lab is used to evaluate the verification scheme, and the experimental results show the efficiency of the scheme.
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Computer Engineering. 2009, 35(4): 23-24. https://doi.org/10.3969/j.issn.1000-3428.2009.04.008A novel method for index-building of TPR*-tree is proposed, which splits the moving object set at root node level by using velocity vector. According to the value of velocity vector, the moving objects are clustered into different sub-nodes, which then constructs the TPR*-tree. The records of moving objects are stored by using overflow bucket at root node level, and the index of TPR*-tree is inserted and updated with a batch, which decreases the cost of insertion maintenance. Experimental results show this method is feasible.
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Computer Engineering. 2009, 35(4): 25-27. https://doi.org/10.3969/j.issn.1000-3428.2009.04.009User location estimation is the precondition of the services in Wireless Local Area Network(WLAN). Aiming to improve both QoS aspects including accuracy and real time of WLAN, this paper conducts the research on localization technology based on Received Signal Strength Indicator(RSSI), and proposes an algorithm for WLAN location estimation based on Gauss Mixture Model(GMM), which consists of an offline training phase and a real time localization phase. The RSSI is also modeled by GMM, which decreases the error and the computation, and improves the real time of WLAN user localization. Simulation experimental results show this algorithm has better performance in both accuracy and real time.
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Computer Engineering. 2009, 35(4): 28-30. https://doi.org/10.3969/j.issn.1000-3428.2009.04.010Aiming at the problems that it is difficult to estimate the cost and workload during the maintenance period of software development, a function point measurement method based on Java program is presented. The counting rules for extracting data and transactional function points from object program are also introduced. An example of Java source code is given to explain the detail of the measurement process. Experimental results show this method is effective and feasible.
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Computer Engineering. 2009, 35(4): 31-34. https://doi.org/10.3969/j.issn.1000-3428.2009.04.011Tabu Search(TS) algorithm is one of the global optimization search methods which has strong local search and is applied for a large number of combinatorial optimization problems. In the paper, an improved TS algorithm is proposed for protein Three-Dimensional(3D) folding structure prediction in AB off-lattice model. Experimental results show that the lowest energies computed by improved TS algorithm are better than those obtained by previous methods. Given a protein sequence, its lowest-energy conformation obtained by the improved TS forms a single hydrophobic core, which suggests that AB model in three dimensions appears to reflect real protein reasonably. Compared with previous heuristic approaches, improved TS algorithm has higher performance and can be effectively used to predict 3D structure prediction of proteins.
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Computer Engineering. 2009, 35(4): 35-37. https://doi.org/10.3969/j.issn.1000-3428.2009.04.012This paper points out several problems of current researches on XML stream filtering, and uses keyword search method as a solution. Based on the conception of Rightmost Contain Border(RCB), it implements an algorithm called XVirtualStack via using a virtual stack for keyword search over XMLstream. The theoretical analysis and experimental results validate that this algorithm is efficient.
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Computer Engineering. 2009, 35(4): 38-40. https://doi.org/10.3969/j.issn.1000-3428.2009.04.013There are many differences between the codes produced by existing decompilers and the corresponding source codes. To find and understand these differences can help to improve and refine the design of decompiler. This paper presents a differencing algorithm for decompilation code and source code of a C program. This algorithm is based on syntax tree matching method. A new C program intermediate representation is defined and a dynamic expression matching method is proposed to improve the accuracy of the syntax tree matching method. Experimental results show that this algorithm is able to find out most differences between decompilation code and source code.
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Computer Engineering. 2009, 35(4): 41-43. https://doi.org/10.3969/j.issn.1000-3428.2009.04.014In order to improve the reliability and efficiency of embedded application design, this paper realizes an RTEMS-oriented Integrated Development Environment(IDE) for embedded software. A buffer overflow checking module is integrated into the compilation procedure, and it can detect buffer overflow while program running which efficiently improves system reliability. The remote debug module based on gdbstub is integrated to development environment which can be used to customize RTEMS. The development and debugging efficiency of the embedded software are enhanced, and design cycle is shortened.
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Computer Engineering. 2009, 35(4): 44-47. https://doi.org/10.3969/j.issn.1000-3428.2009.04.015This paper proves that some subclasses of Petri nets have confluence property, such as live marked S-graphs, live marked T-graphs, bounded conflict-free Petri nets and bounded marked T-graphs, discusses the preservation problems for confluence property in synchronous and sharing synthesis of Petri net systems, and finds that complex net systems composed by these simple subclasses also have confluence property. An example of complex net systems with confluence property is given to verify the conclusion.
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Computer Engineering. 2009, 35(4): 48-50. https://doi.org/10.3969/j.issn.1000-3428.2009.04.016This paper designs a DOM liked tree data structure for developing a minimal DOM based eXtended Marked Language(XML) coding and encoding module. When parsing XML text, based on expat, it puts the parsed content into the tree. When encoding, it constructs a DOM tree, then use non-recursion depth-first method to access the tree and serialize it into XML text. This module also solves the key problem of international language, and forms an universal, highly effective and industrial-level-reached basic module for XML application.
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Computer Engineering. 2009, 35(4): 51-52. https://doi.org/10.3969/j.issn.1000-3428.2009.04.017Aiming at the contradiction between consistency, responsiveness and concurrency in concurrency control of Collaborative Virtual Environment(CVE), a client-based concurrency control mechanism is proposed in this paper. The consistency is guaranteed and improved through the state information of sharing objects which is preserved in client. Attribute-based concurrency control is introduced to promote the responsiveness of CVE system. Experiment shows that the consistency, responsiveness and concurrency of CVE system can be well balanced by the control mechanism.
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Computer Engineering. 2009, 35(4): 53-55. https://doi.org/10.3969/j.issn.1000-3428.2009.04.018Because of the busy ratio of operation and uneven distribution of resources, the individual disk pool may be led to decrease the I/O speed of response and the normal response to the request is affected. By the Logical Disk(LD) migration processing between disk pools, a reserved LD can created by using the spare capacity. By parallel data migration on idle time background, the IOPS of storage system can be around increased by 8%. Through the exchange of LD metadata information, it is possible to avoid an external point of the Mount.
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Computer Engineering. 2009, 35(4): 56-57. https://doi.org/10.3969/j.issn.1000-3428.2009.04.019This paper studies the attribute of test sequence inherent in the parallel test, and proposes the parallelizability of test sequence. The parallelism solves the problem that the difference of test efficiency improvements in parallel test can not be explained. Also this criterion can guide the engineering through the selection of instruments resource in the Automatic Test System(ATS). Experimental result shows that the parallelizability is the quality inherent in the test sequence, and the conception of parallelism is valid.
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Computer Engineering. 2009, 35(4): 58-60. https://doi.org/10.3969/j.issn.1000-3428.2009.04.020Based on the analysis of benchmark program’s memory access behavior, this paper proposes stride and pointer based prefetching scheme which can capture regular data access pattern and pointer access pattern, and implements a prefetcher between L2 cache and memory using a global history buffer. Full system simulation shows that this prefetching scheme can improve the commercial benchmark’s performance by 14%, and improve the scientific benchmark’s performance by 34.5%.
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Computer Engineering. 2009, 35(4): 61-62. https://doi.org/10.3969/j.issn.1000-3428.2009.04.021This paper introduces an overall design of a kind of Internet-based supervisory software. The infrastructure of data platform and the objectives of the software are described. Details of the C/S architecture of the software are presented, during which the information exchange inside the software and between the software and the system, the modules of the software are given. An access management module is designed to manage the concurrent control request from users.
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Computer Engineering. 2009, 35(4): 63-65. https://doi.org/10.3969/j.issn.1000-3428.2009.04.022Unified Modeling Language(UML) statechart diagram is a system testing technique used to test software systems. It is the extension of requirement-based regression testing. Through the dependency analysis, this paper generates the UML statechart diagram and dependency diagram. The approach identifies the original model and the modified model. It provides a method for the program comprehension, errors finding and modification during the process of regression testing. A case study named SATM is given to show the applicability of the method used in the regression test.
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Computer Engineering. 2009, 35(4): 66-68. https://doi.org/10.3969/j.issn.1000-3428.2009.04.023Aiming at the quality of XML data, this paper proposes a new XML data cleaning method based on XML key, the information of multiple templates Hidden Markov Model(HMM) draw-out strategy and Particle Swarm Optimization(PSO). For boosting the parallel detection efficiency of the XML similarity records, a wave function is used to give relevant improvements to PSO. Contrasted with other XML data cleaning algorithms, simulation experiments show that the optimized algorithm has powerful adaptive learning capability, lower labor cost, less calculation and better time rate around 94%.
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Computer Engineering. 2009, 35(4): 69-71. https://doi.org/10.3969/j.issn.1000-3428.2009.04.024Information and communication technologies allow customers utilize and manage distributed and heterogeneous data sources. This paper puts forward a solution for application server based on XA interface to implement the communication and distributed transaction processing between different data sources. Through the mechanism of integration between application server and heterogeneous data sources, an external data sources integration model based on XA interface is presented. On the basis, the resource service of application server is designed and implemented to seamlessly integrate the heterogeneous data sources with application server.
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Computer Engineering. 2009, 35(4): 72-74. https://doi.org/10.3969/j.issn.1000-3428.2009.04.025Aiming at the information service in distributed resource management, this paper proposes a uniform resource information model, a resource information server which provides centralized, uniform information service. After testing and analyzing the impact to the performance of the whole system, it is proved the method can improve the whole system.
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Computer Engineering. 2009, 35(4): 75-77. https://doi.org/10.3969/j.issn.1000-3428.2009.04.026In research of ontology mapping, the mapping between real ontology or large-scale ontology is difficult. This paper proposes a mapping method for large class hierarchies, which is one kind of the large-scale ontologies. Based on ontology structure and semantic distance between classes, the classes can be put in a multi-dimension space by using Vector Space Model(VSM). Two large class hierarchies are partitioned into small blocks respectively by applying CURD clustering algorithm, and then blocks from different hierarchies are matched by comparing the reference points. Experimental results show that the method performs well on the test cases.
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Computer Engineering. 2009, 35(4): 78-79. https://doi.org/10.3969/j.issn.1000-3428.2009.04.027Association rules mining in data mining reflects relations between events, but it has privacy problems. In order to raise the protection level of data privacy, this paper proposes an effective privacy preserving algorithm namely Privacy Preserving Association Rules Mining(PPARM). It can hide sensitive association rules which contain sensitive items by the way of proper item deletion. Theoretical analysis and experimental results show that the method is simple and has get good privacy.
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Computer Engineering. 2009, 35(4): 80-82. https://doi.org/10.3969/j.issn.1000-3428.2009.04.028By relying on an intrinsic property of the Generalized Conjugate Residual(GCR) algorithm and eliminating data interdependence for inner product computation in the GCR algorithm, an improved parallel GCR algorithm is proposed for solving large non-symmetric sparse linear systems in this paper. The convergence of IGCR algorithm is the same as GCR algorithm, but the times of the synchronization overhead are reduced by a factor of two when it computes using the IGCR algorithm on distributed memory cluster systems based on MPI environment. The numerical result and theoretical analysis prove that the performance of the IGCR algorithm is better than that of the GCR algorithm.
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Computer Engineering. 2009, 35(4): 83-84. https://doi.org/10.3969/j.issn.1000-3428.2009.04.029This paper introduces an optimization approach for cost function computing. It eliminates the redundant computation in the process of computing matching cost. The key of the algorithm is the current matching cost computation depending on the previous matching cost computing result. It is verified by the matching cost function based on correlation window, such as SAD, SSD and DP. Experimental results indicate that the approach is efficient and feasible without changing the matching precision.
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Computer Engineering. 2009, 35(4): 85-87. https://doi.org/10.3969/j.issn.1000-3428.2009.04.030Against the redundant communication code produced in the process of automatic parallel code generation, this paper presents an algorithm to eliminate redundancy communication based on Define-Use analysis. Intermediate code is divided into all kinds of blocks by process, and the information of defining and using of array is collected. Blocks are constructed into Control Flow Graph(CFG). Based on CFG, the positions needed communication are fixed according to Define-Use analysis to eliminate redundancy communication code and optimize communication. Test result shows that the algorithm effectively improves the performance of parallel code.
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Computer Engineering. 2009, 35(4): 88-90. https://doi.org/10.3969/j.issn.1000-3428.2009.04.031This paper proposes a pre-merged repeats masking-off method by studying repeats analysis in DNA fragment assembly. The method can recognize and merge the different shotgun fragments owning the same overlap substring by scanning the shotgun set, and mark the position of the repeats and masking-off them before DNA fragment assembly. Simulations show that the rate of false repeats recognition with the method is descended, and CPU time of DNA fragment assembly is reduced because of pre-merged method.
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Computer Engineering. 2009, 35(4): 91-93. https://doi.org/10.3969/j.issn.1000-3428.2009.04.032This paper uses ns-2 simulation to evaluate the fairness between four mainstream high speed TCP variants and DCCP in various network environments. Simulation shows that, concerning fairness to DCCP, the performances of the four variants are as follow: CUBIC(best), HS-TCP, BIC, STCP(worst). The results contributes to a more comprehensive assessment of the high speed TCP variants and also provides guidelines for the design of new variants.
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Computer Engineering. 2009, 35(4): 94-96. https://doi.org/10.3969/j.issn.1000-3428.2009.04.033This paper introduces the principle of communication between the serial communication module of TMS320F2812 DSP and serial peripherals, and gives the asynchronous serial communication programming combined with actual application. According to the problem that it is hard to watch variables of power driving digital control systems, computed data by DSP are sent to PC through the serial port RS232. Thanks to using LabVIEW as the PC developing platform, data storage, data processing and data display are realized without extra hardware. Specific data analysis and processing can be achieved by the system, such as the FFT transform, harmonic analysis. Four way experimental waveforms of data generated by DSP displayed in LabVIEW are given out.
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Computer Engineering. 2009, 35(4): 97-99. https://doi.org/10.3969/j.issn.1000-3428.2009.04.034The on-demand routing protocol DSR is a good performance protocol in mobile Ad Hoc networks. However, the defect of it is that it is not quick enough to adapt the fast-changing topology of the Ad Hoc networks. It causes many unneeded times of route discovering, and the data-packets always don’t take the shortest route. These result in the low-efficiency. To solve the problem, DSR is optimized in this paper, and a mechanism called local self-adaptation is proposed, which can recover and adjust the route automatically. Also it presents a new routing protocol called LSDSR, which can obviously decrease the times of route discovering and transmission latency, and much more adapt to the real-time performance.
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Computer Engineering. 2009, 35(4): 100-102. https://doi.org/10.3969/j.issn.1000-3428.2009.04.035For the demand of distance laboratory test data transmission in real time and synchronization, based on the diversity of data sources of distance laboratory system, a new network protocol which is based on session is presented. The Distance Laboratory Session Protocol(DLSP), which is based on TCP/IP, through virtual channel multiplexing, and the concept of session is introduced. A criterion to the test host of network communication efficient is given. The result of test shows that good effect and synchronization is archived in data transmission in real time, due to DLSP.
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Computer Engineering. 2009, 35(4): 103-104. https://doi.org/10.3969/j.issn.1000-3428.2009.04.036The communication between PC and PLC is realized under free port mode based on VB6.0. In the experiment, on the basis of the characteristics of PC and PLC communications and free port communication features, PC-PLC process and means of communication are studied. The combination of VB and the Windows API functions can gain the time of communications between PC and multi-PLC in different means of communication. The advantages and the disadvantages of different forms of communication in the communication time and the structure are compared, and implementation instances are presented to different communications occasions.
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Computer Engineering. 2009, 35(4): 105-107. https://doi.org/10.3969/j.issn.1000-3428.2009.04.037On the current scale of the Internet, the single Web crawler is unable to visit the entire Web in an effective time-frame. This paper develops a distributed Web crawler system to deal with it. In the distribution design, it mainly considers two facets of parallel. One is the multi-thread in the internal nodes; the other is distributed parallel among the nodes. It focuses on the distribution and parallel between nodes, and addresses two issues of the distributed Web crawler, which include the crawl strategy and dynamic configuration. Experimental results show that the hash function based on the Web site achieves the goal of the distributed Web crawler. The ability of the single node in distributed Web crawler should not decrease so much with the single Web crawler. Aiming at the load balance of the system, the communication and management costs reduce as much as possible.
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Computer Engineering. 2009, 35(4): 108-109. https://doi.org/10.3969/j.issn.1000-3428.2009.04.038An integrate photoelectric chip just realizes small light First Come First Serve(FCFS) buffer, and can not achieve big buffer. This paper makes use of the characteristic that access link rate is highly less than bankbone link bandwidth, and under the condition of sacrificing 25% of bankbone link bandwidth, discusses if small buffer can suffice the performance requirement of an all-optical packet switching router based on CIOQ buffer queue. It demonstrates the buffer requirement of router based on CIOQ queue is highly less than the buffer requirement of router based on OQ buffer queue. Through analysis and emulation, it finds 20 packets can suffice performance requirement of bankbone router.
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Computer Engineering. 2009, 35(4): 110-112. https://doi.org/10.3969/j.issn.1000-3428.2009.04.039Thi paper analyzes the problems in standard TCP slow start algorithm when it is applied to the network environment including GEO satellite links. To solve these problems, a new improved TCP slow start algorithm based on RTT fairness is proposed, termed RFB-SS. RFB-SS algorithm uses the larger initial window mechanism. And in the early slow start phase, the congestion window remains exponential growth, in the late phase, by using window control growth factor, the congestion window of larger RTT increases faster, otherwise increases slower. Performance analysis and simulation results show that RFB-SS algorithm slows down the congestion window growth rate, and weakens the TCP flow of smaller RTT in the aggressive bandwidth competition in the late slow start phase. To a certain extent, RFB-SS algorithm obtains a fair sharing of available bandwidth among different RTT flows.
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Computer Engineering. 2009, 35(4): 113-115. https://doi.org/10.3969/j.issn.1000-3428.2009.04.040In mobile Ad Hoc networks, the mobility of nodes has negative impact on end-to-end performance. To quantify this impact, this paper proposes a MANET performance analyzing model based on virtual clock with link availability theory, which defines the time period from a packet generation to its successful transmission to the next hop as the virtual clock. Through this model, path throughput and average packet end-to-end delay can be accurately obtained. And how speed and transmission range and density of nodes affect the measurements of end-to-end performance can be analyzed.
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Computer Engineering. 2009, 35(4): 116-118. https://doi.org/10.3969/j.issn.1000-3428.2009.04.041This paper reviews the works about router buffer sizing in Internet routers. In term of rapid development of real-time video operation, it studies the impact of small buffer on real-time traffic, and analyzes the impact on the performance of network based on NS2. It concludes that when load is lower, small buffer can suffice the requirement of real-time operation.
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Computer Engineering. 2009, 35(4): 119-120. https://doi.org/10.3969/j.issn.1000-3428.2009.04.042This paper explores the problems of rate adjustment in congestion control strategy of layered multicast based on receiver-driven. A rate adjustment algorithm based on receiver-estimated is proposed. Thus it solves the problems of fine-grained rate adjustment. The theory and experimental results show that the algorithm can make the receivers’ bandwidth of heterogeneous chains be fully utilized. And it is with good TCP-friendly and scalability.
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Computer Engineering. 2009, 35(4): 121-124. https://doi.org/10.3969/j.issn.1000-3428.2009.04.043Conventional Open Shortest Path First(OSPF) protocol works in many kinds of complicated environment. So it seems too expensive when used to construct Ad Hoc network for conventional OSPF protocol. This paper designs a simplified OSPF protocol, and proposes an effective method in constructing Ad Hoc network based on the simplified protocol. It establishes mathematical model to evaluate the ability of rebuilding the network topology when some errors happen. It is proved that Ad Hoc network meets the requirements of self-construct and wrong-sensitive. This kind of network may work well under complicated circumstance like battlefield.
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Computer Engineering. 2009, 35(4): 125-127. https://doi.org/10.3969/j.issn.1000-3428.2009.04.044According to the characteristics of Webmail, this paper proposes a new attack method based on DNS Cache Poisoning, and presents an attacking framework. Experimental results show that it can attack Live Mail successfully, so it can testify the potential risk of DNS Cache Poisoning. Three methods are given to defense the attack.
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Computer Engineering. 2009, 35(4): 128-130. https://doi.org/10.3969/j.issn.1000-3428.2009.04.045The paper proposes a new threshold proxy re-signature scheme. In the standard proxy re-signature scheme, a semi-trusted proxy can transform Alice’s signature into Bob’s signature on the same message, but in this scheme there are n semi-trusted proxies between the two signers and the re-signature generation can be performed if and only if there are at least t proxies. This scheme holds the features of proxy re-signature and threshold signature, so it is especially suitable for some complicated checking and voting system.
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Computer Engineering. 2009, 35(4): 131-132. https://doi.org/10.3969/j.issn.1000-3428.2009.04.046Multiplication operation over the finite field is the most crucial part in the elliptic curve cryptosystems. It operates a faster addition and simpler square with the elements representing on the finite field, but the comparison of the multiplication has become the bottleneck of operation. To solve this problem, This paper puts forward a modified scheme based on analyzing serial multiplication, with which compared the scheme reduces the operation cycles greatly, enhances the speed efficiently, and designs the parallel multiplier structure based on the modified scheme. This paper implements the modified scheme on FPGA, and lays hardware basis on improving elliptic curve encryption speed.
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Computer Engineering. 2009, 35(4): 134-136. https://doi.org/10.3969/j.issn.1000-3428.2009.04.047Due to the lack of flexibility and extendability of the security policy conflict detection and resolution algorithms, this paper proposes a security policy specification based on multidimensional integer space. An algorithm based on the specification is proposed, the correctness of the algorithm is proved and the complexity is analyzed. The automatic Security Policy Conflict Detection and Resolution Tool(SPCDRT) is designed and implemented.
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Computer Engineering. 2009, 35(4): 137-139. https://doi.org/10.3969/j.issn.1000-3428.2009.04.048Aiming at the problems existed in security protection mechanism of IMS media level, a user-oriented uniform security frame in IMS media level is presented. The design scheme is given in detail, which provides users with security protection mechanism of media level flexibly. The security negotiation between encryption algorithm and the key at media level is implemented, and the communication security between users with end to end is guaranteed. Experimental results show this scheme is effective.
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Computer Engineering. 2009, 35(4): 140-142. https://doi.org/10.3969/j.issn.1000-3428.2009.04.049This paper presents a high-speed Elliptic Curve Cryptography(ECC) co-processor suitable for both prime number field and binary field, which supports all curve and field polynomials. The co-processor can implement all basic operations used in ECC and perform ECDSA and other modified algorithms by instructions. Operands of the co-processor can be of any length no more then 384 bit. Many methods such as word-level multiplier, separate operands and RAM array are used to improve the performance of the system.
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Computer Engineering. 2009, 35(4): 143-145. https://doi.org/10.3969/j.issn.1000-3428.2009.04.050This paper analyzes existing reputation models, proposes a P2P reputation model using trust mechanisms and recommendation mechanisms, and optimizes the model by the mentality of decision tree. It puts forward a method that can access global trust value in distributed P2P system, and resolves signal peer invalid problem. Experimental results prove that this model is better than existing models in estimating trust value accuracy and distinguishing untrue peers.
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Computer Engineering. 2009, 35(4): 146-148. https://doi.org/10.3969/j.issn.1000-3428.2009.04.051According to the features of net data current rule and the changing compared with ordinary circumstances when DDoS attacks, this paper proposes that the changing function of statistical rule can be gained by CUSUM method of sequential detection to inspect the relavant changing point. It proves that the CUSUM method without parameter is a simple and effective intrusion detection system of little calculation needing no complex parameter. By this method, DDoS attack can be analyzed immediately and detection function can be improved.
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Computer Engineering. 2009, 35(4): 149-151. https://doi.org/10.3969/j.issn.1000-3428.2009.04.052The paper proposes a new fair document exchange protocol. In such a fair exchange scenario, each party owns a valuable secret message and they want to exchange their secrets in a fairness way so that at the end of the transaction, either both of them get the other’s secret or neither of them gets the other’s secret. Compared with previous fair exchange protocols, the protocol holds confidentiality, that is, except the two participating party, no one even the Trusted Third Party(TTP) can get exchanged items.
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Computer Engineering. 2009, 35(4): 152-153. https://doi.org/10.3969/j.issn.1000-3428.2009.04.053This paper presents an identity-based proxy signature scheme to solve the proxy signature problem, which includes such five algorithms: setup, enroll, sign, verify and Trace. With the theory and approach of provable security, it proves that under the Computational Diffie-Hellman(CDH) and the subgroup decision assumptions, the scheme has the properties of anonymity and traceability.
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Computer Engineering. 2009, 35(4): 154-156. https://doi.org/10.3969/j.issn.1000-3428.2009.04.054Aiming at the problems existed in the process of using Network Driver Interface Specification(NDIS) to implement IPSec VPN system, a new IPSec VPN system based on firewall hook is presented, and the data packet filtering technology for firewall hook at Windows network layer is researched, which upgrades the IPSec encapsulation processing to network layer and implements it. This system can effectively solve the problems caused by NDIS such as MTU, routing and reassembly. It promotes the processing efficiency and has better performance of application.
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Computer Engineering. 2009, 35(4): 157-158. https://doi.org/10.3969/j.issn.1000-3428.2009.04.055Broadcast encryption scheme is a wildly used scheme in group security communication, which has good application foreground in such fields as pay-TV, video-conferencing, and Wireless Sensor Network(WSN). This paper presents a new randomized broadcast encryption scheme, which distributes keys for users by constructing family of random functions. It makes legal users gain decryption keys with probability as one, and the key storage number of users is (l+1). Compared with other schemes based on binary tree structure, this scheme has advantages in quantity of key storage, and it reduces transmission cost to minimum under some conditions.
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Computer Engineering. 2009, 35(4): 159-161. https://doi.org/10.3969/j.issn.1000-3428.2009.04.056Traditional associative rule mining algorithm is mostly based on the support-confidence framework, which disable the in-depth study of frequent items for time and space limitations. There is few study of associative classification incremental learning currently. This paper presents a new incremental associative classification method, which can solve the incremental learning problems of data with class attribute, and realize the fast extraction and maintenance of associative rule with limited time and space when the data is updating frequently. Experimental results show that this method can quickly and effectively maintain and update the classification rules, which avoid re-learning the history samples and ensure the predictability of the classification model.
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Computer Engineering. 2009, 35(4): 162-164. https://doi.org/10.3969/j.issn.1000-3428.2009.04.057Based on the analysis of 34 stream ciphers such as A5, Grain and Trivium, this paper researches the structure of the linear and nonlinear feedback shift registers and summarizes the relevant operation characteristics. The special feedback shift register instructions are proposed, through configuration, which can realize multiple feedback shift registers with various structures as well as combinations formed by them. The reconfigurable hardware prototype is fabricated. This design is flexible and efficient, which can be a core function unit of the application specific microprocessor for stream ciphers.
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Computer Engineering. 2009, 35(4): 165-166. https://doi.org/10.3969/j.issn.1000-3428.2009.04.058This paper presents a privilege delegating and access control model for P2P. This model includes three main protocols, such as privilege delegate protocol, resources search protocol, and access control protocol. Privilege delegate protocol defines that the task initiator, PEER_S selects delegated peers PEER_D who will delegate PEER_S to finish tasks with highest trust value, and awards privilege delegation certificate Cd. The resources search protocol defines that PEER_D send resource request to the provider with the highest trust value. The resource access protocol defines the PEER_R access control of resource with the credit certificates Cts and privilege delegation certificate Cd of requesting peers. By CPN Tools, the protocols are simulated based on the characteristics with colored Petri-net, such as reachability.
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Computer Engineering. 2009, 35(4): 167-169. https://doi.org/10.3969/j.issn.1000-3428.2009.04.059In order to improve the zero digital image watermarking method against rotation attack ability, this paper proposes one method based on DWT, which can against rotation attack ability efficiently. For rotation causing distortion, it makes use of Log-Polar Maping(LPM), which can transform rotation problem in Castesian coordinate to translation property in LPM coordinate. After translation, it uses an exhaustive search to detect test image involves watermarking or not. Experimental results demonstrate the method can obtain better visual effect.
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Computer Engineering. 2009, 35(4): 170-171. https://doi.org/10.3969/j.issn.1000-3428.2009.04.060This paper presents a novel robustness algorithm. It uses an improved curvature scale space technology to obtain a few robust corner points to rebuild the image suffered geometric attacks. Two chirp signals as the watermark are selected and embedded into the discrete Fractional Fourier Transform(FRFT) domain of the image. The transform orders and the matrices of the position where the watermark is embedded are used as encryption keys of the algorithm. With the help of the property that a chirp signal can produce a strong impulse in the FRFT domain, the watermark can be detected conveniently. Simulation experimental results show that this algorithm assures good imperceptibility, security and robustness.
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Computer Engineering. 2009, 35(4): 172-174. https://doi.org/10.3969/j.issn.1000-3428.2009.04.061Radio Frequency Identification(RFID) tags have the advantages of concealment, convenience and high efficiency, and can be used as new carriers of secret storage. Aiming at implementing secret sharing in RFID tags group, this paper proposes a verifiable threshold secret sharing scheme, which is fit for RFID system, and analyzes its security features. According to characteristics of RFID system, the first authenticating then reading implementing principle is suggested. The security of this scheme is based on the mutual authentication of reader and tags and the difficulty of computing the discrete logarithm modulo for a composite number.
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Computer Engineering. 2009, 35(4): 175-176. https://doi.org/10.3969/j.issn.1000-3428.2009.04.062Started with the issues related to evaluation of image steganalysis algorithm, the index for evaluation of steganalysis algorithm is analyzed. The evaluation and comparison to performance of steganalysis algorithm are implemented by using FCM algorithm. This evaluation algorithm can not only conduct evaluation to existed steganalysis algorithm, which chooses out the best one, but also conduct evaluation to new steganalysis algorithms. Experimental results show this evaluation algorithm is effective.
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Computer Engineering. 2009, 35(4): 177-179. https://doi.org/10.3969/j.issn.1000-3428.2009.04.063To implement the image copyright and integrality authentication, a dual watermarking algorithm based on DCT and chaos is proposed. The image is transformed by DCT, and the robust watermarking is embededd into low frequency parts by using SVD and the fragile watermarking is embedded into high frequency parts by using comparison pairs of coefficients, which implements blind detection. Simulation experimental results show that the robust watermarking is good at robustness to JPEG, and the fragile watermarking can resist to noise attack, thus this algorithm is effective.
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Computer Engineering. 2009, 35(4): 180-182. https://doi.org/10.3969/j.issn.1000-3428.2009.04.064The former symmetric encryption algorithms use substitution and transposition techniques. This paper presents a symmetric encryption algorithm based on circle property. The techniques of random number and cryptographic hash function are used in this algorithm. So the cipher text randomly distributes in the n-dimensional space and led to cryptanalysis being difficult. From the security analysis the brute-force attacks are infeasible. It is applicable for encryptions with timestamp and short plain text encryptions. Experimental results verify that this algorithm is feasible.
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Computer Engineering. 2009, 35(4): 183-186. https://doi.org/10.3969/j.issn.1000-3428.2009.04.065Density extraction method has difficulty in representing local distribution and its stochastic feature from the extracted density information. This paper proposes a solution to solve this problem, combing density method with stochastic distribution estimation. The method computes the density of each single small plot, and combines it with the overall density of the point cloud. A parameter is obtained, which can reflect the local aggregation feature. Tests show that this parameter can satisfactorily provide reliable data on estimating stochastic distribution and homogeneity of the point cloud.
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Computer Engineering. 2009, 35(4): 187-189. https://doi.org/10.3969/j.issn.1000-3428.2009.04.066Simulating the automated negotiation based on Co-evolutionary Genetic Algorithm(CGA) is a new topic in intelligent computing and multi-Agent system. According to the status that most literatures deal with the single-issue negotiation, this paper puts forward a multi-issue negotiation simulating algorithm based on CGA and fitness sharing Niche technique. Simulation experiment uses the alternating offer protocol as an example to carry out, and validates that the algorithm forms local Niches in strategy populations and produces the set of approximate Pareto optimal strategies set.
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Computer Engineering. 2009, 35(4): 190-192. https://doi.org/10.3969/j.issn.1000-3428.2009.04.067A method based on multi-hue-blob correlation matching voting is proposed to solve target tracking problem of the moving target under occlusion efficiently in nonrigid target tracking. It uses invariable hue feature to achieve adaptive blobbing, and gains target’s motion state through combined estimate of blobs’ motion states. Experimental results indicate it is robust and has reliable performances under the case of heavy occlusion of the nonrigid moving object.
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Computer Engineering. 2009, 35(4): 193-195. https://doi.org/10.3969/j.issn.1000-3428.2009.04.068This paper presents a segmentation algorithm which comprehensively utilizes various attributes of video texts, such as temporal and spatial, strokes, color, geometric. The algorithm uses multi-frame integration to enhance the images, performs the stroke operator to extract the character strokes based on the feature of the stroke width, analyses the color of the character strokes according to the stroke image and extracts the color layer of the character, removes the background with the same color and noises in the color layer of the character by the improved connected components analysis. Experimental results indicate that the proposed algorithm preferably solves the text segmentation problem which involves in a complex background, and its performance precedes that of the traditional method.
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Computer Engineering. 2009, 35(4): 196-198. https://doi.org/10.3969/j.issn.1000-3428.2009.04.069This paper presents a novel approach based on Pseudo-Zernike Invariant Moments(PZIM) and Probabilistic Neural Network(PNN) to recognize license plate Chinese characters. The approach makes better use of the rotation invariant and good anti-noise performance of Pseudo-Zernike moments and quick learning rate of PNN, and thus provides a real-time recognition of gray character images by utilizing Pseudo-Zernike moments as feature vectors and Probabilistic Neural Network as classifier. Numeral experiment confirms that it is an effective way to classify license plate Chinese characters.
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Computer Engineering. 2009, 35(4): 199-200. https://doi.org/10.3969/j.issn.1000-3428.2009.04.070A method of applying Non-negative Matrix Factorization(NMF) group strategy for face recognition is put forward. It divides the training images into groups. NMF is applied to the each group’s images to obtain the non-negative subspace constructed by basic image of each group’s images, project the training images and testing images to each feature subspace. The extracted feature coefficents of each group’s images are mixed for recognition based on the nearest neighbor principle. Simulation experiments illustrate the effectivity of the method on the ORL face database.
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Computer Engineering. 2009, 35(4): 201-203. https://doi.org/10.3969/j.issn.1000-3428.2009.04.071This paper uses Level-Set-Based Particle Swarm Optimizion(LSBPSO) to solve the problem of disk load balance. The characteristic of convergence of the algorithm swiftly adjusts the mapping between logic disk and physic disk which uses the technique of disk striping. It refers a new method to forecast the hot of logic disk and adds the content of expression of hot of physic disk. Simulation shows that the algorithm is efficient and defective.
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Computer Engineering. 2009, 35(4): 204-206. https://doi.org/10.3969/j.issn.1000-3428.2009.04.072In order to improve convergent speed and search precision of orthogonal genetic algorithm, a local search scheme is introduced into orthogonal genetic algorithm and a new clustering local search operator is proposed. The orthogonal operator is used to generate an initial population of points that are scattered uniformly over the feasible solution space, so that it can maintain diversity of the initial population. The orthogonal operator is used for a global search to guarantee the global convergence, a new clustering local search operator is adopted to make a local search in order to improve the convergence speed and the search precision. The new approach is tested on seven benchmark functions with high dimensions. Compared with other algorithms, the new algorithm has better search precision, convergent speed and capacity of global search.
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Computer Engineering. 2009, 35(4): 207-209. https://doi.org/10.3969/j.issn.1000-3428.2009.04.073This paper uses the inverse of Makespan as antibody, which is calculated by priority heuristic algorithm. It presents a Self-adaptive Clone Heuristic Algorithm(SACHA) based on the prior algorithm to solve Job Shop scheduling problem. SACHA adapts real code and it designs a kind of self-adaptive clone operator based on the distance between antibodies. The amounts of clone and excitation are assigned among antibodies adaptively. It simulates the dynamic process of adjusting the amount of antibody clones adaptively. Simulation tests of FT10 and FT06 show that the algorithm is stable and good.
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Computer Engineering. 2009, 35(4): 210-211. https://doi.org/10.3969/j.issn.1000-3428.2009.04.074According to the problem that the standard Particle Swarm Optimization(PSO) easily traps in a local optimum, this paper presents a method that the current particle chooses the one with the best fitness in its visual as the global best particle. Experiment shows the advantaged algorithm has better global search ability. When it is applied to the group animation, the particle has good artificial intelligence performance, and can simulate group behavior in an actual way.
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Computer Engineering. 2009, 35(4): 212-214. https://doi.org/10.3969/j.issn.1000-3428.2009.04.075A novel method for machinery fault diagnosis combining wavelet packet analysis and multiple support vector machine classifier is put forward. The method has little duplicating training samples and is simple, and its classification accuracy rate is very high. Experimental results show that the method proposed above can successfully be applied to diagnosis of machinery faults, and the best training set is discussed in this paper.
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Computer Engineering. 2009, 35(4): 215-217. https://doi.org/10.3969/j.issn.1000-3428.2009.04.076This paper proposes a segmentation method for accumulation of qusic-circular object with multiplex methods, as the image’s foreground and background is simple at color or gray level. It uses a series method such as filtering to get a preprocess result, and does spot projection to get circum-rectangle of the accumulation object in order to get rid of the noise’s interference. It uses improved gray co-occurrence matrixes to reserve the contradiction of window’s size and the precision of segmentation. 2D OTSU threshold is used to get a precise segmentation result. Experimental results show that the area segmented by the method is clear and with high veracity.
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Computer Engineering. 2009, 35(4): 218-220. https://doi.org/10.3969/j.issn.1000-3428.2009.04.077Block lossy image compression often introduces quantization noise which exhibits block artifact in the reconstructed image especially when the compression ratio is high. This paper introduces a deblock algorithm using space domain adaptive filtering. The algorithm uses an edge-adaptive filter to smooth the block edges of the image to alleviate the block artifact. The uniform blocks of the image is detected using a variation-based method and is smoothed using a neighbor block-relied filtering method. Experimental results show that the block artifact is alleviated effectively while PSNR is improved in the objective respect.
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Computer Engineering. 2009, 35(4): 221-222. https://doi.org/10.3969/j.issn.1000-3428.2009.04.078In order to get a clear image that contains all relevant objects in an area, this paper proposes a new multi-focus image fusion algorithm. It divides the candidate images into small blocks, and constructs the blocks region acutance function to evaluate image definition. What source images the fused block obtains from depends on the region acutance value of the corresponding block. In the endgame, consistency of the fused images is verified by means of voting, and the adjacent blocks from different candidate images are weighted and fused. Experimental results prove that this algorithm is faster and more precise than traditional wavelet-based fusion.
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Computer Engineering. 2009, 35(4): 223-225. https://doi.org/10.3969/j.issn.1000-3428.2009.04.079Snakes model is usually used for semi-automatic image segmentation for the existence of human interaction. In this paper, on the basis of Gradient Vector Flow(GVF) snakes, a fully automatic image segmentation algorithm based on the analysis of flow field and the minimal path method is proposed. It detects nodes of GVF field, sets the nodes as seeds, acquires an initial segmentation by multiple-label fast sweeping method, and uses a region merging to get the segmentation result. Experiments demonstrate the robustness and effectiveness of the algorithm.
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Computer Engineering. 2009, 35(4): 226-228. https://doi.org/10.3969/j.issn.1000-3428.2009.04.080The quality of voice is an important design request of embedded voice device, especially in MP3, MP4, PDA and mobile telephone. If there is noise it will influence their timbre. This paper analyzes the defects when using the hardware methods to eliminate noise, researches how to use software methods to reduce, prevent and eliminate noise, and gives the design of the software program. The essential functions that should be involved in noise cancellation driver are analyzed. The design is proved to be correct and effective by the successful result.
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Computer Engineering. 2009, 35(4): 229-231. https://doi.org/10.3969/j.issn.1000-3428.2009.04.081This paper studies the performance of H.264/AVC multi-generation coding, presents four mechanisms that contribute to the continued degradation: quantization-transform error, prediction mode re-estimation error, clipping error and deblocking error. To improve the multi-generation performance, it presents a multi-generation coding procedure by selecting the same prediction mode and disabling deblocking filter for each compression stage. Experimental results show that PSNR loss of multi-generation coding decreases 0.5 dB~1.4 dB.
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Computer Engineering. 2009, 35(4): 232-234. https://doi.org/10.3969/j.issn.1000-3428.2009.04.082This paper presents a portable embedded video decoder terminals. Based on the ARM9 processor of Samsung and the embedded Linux operating system, receiving, decoding and playback of video in real time are achieved, and the video compression standard is H.264. The research background and research process of this system is interpreted. The framework of the system and the pivotal technologies to achieve are offered. The system integrates the advanced video compression technology with embedded system. Highly efficient communication platform is achieved, which has significance for the project and market value.
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Computer Engineering. 2009, 35(4): 235-237. https://doi.org/10.3969/j.issn.1000-3428.2009.04.083The embedded system has less resources than PC, so the research results for improving video transfer real-time performance are too complex to be suitable for the embedded video surveillance system. This paper proposes a scheme to enhance the real-time performance of video surveillance system and to economize on memory resources. The scheme adopts the linear increment video traffic prediction algorithm and uses the packet paris to detect the available network bandwidth. It proposes a memory allocation algorithm to save memory resources.
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Computer Engineering. 2009, 35(4): 238-240. https://doi.org/10.3969/j.issn.1000-3428.2009.04.084Based on the statistical analysis of eight benchmarks simulation, this paper proposes selective replication for some read-only shared data, and in-situ communication for write-read shared data. The former means to improve cache average access speed, while the latter’s purpose is to reduce coherence overhead. It extends a more simple method to solve the ping-pong problem. Statistical analysis of simulation shows these two schemes achieve less access latency and better space utilization compared with conventional cache scheme.
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Computer Engineering. 2009, 35(4): 241-243. https://doi.org/10.3969/j.issn.1000-3428.2009.04.085This paper analyzes and compares several pattern formats prevalent in the world such as DST, DSB and DSZ. Because these pattern formats do not have the whole embroidery information, and in order to be compatible with these pattern formats, it proposes the customized SYT pattern, realizes the storage of SYT pattern files based on FAT16 file system, and realizes the management of patterns in flash. The research is used in the system of new industrial embroidery machine with independent intellectual property.
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Computer Engineering. 2009, 35(4): 244-246. https://doi.org/10.3969/j.issn.1000-3428.2009.04.086In order to speed up the efficiency of SDRAM controller while reading/writing data blocks, this paper proposes a time-hiding method for the design of SDRAM controller. It implements this method on FPGA. Experiments indicate that this time-hiding method shortens the latency and increases the speed of accessing data blocks. For example, when writing 4×4 data blocks, this method saves access time by 52%, and when reading 8×8 data blocks, this method saves access time by 44%.
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Computer Engineering. 2009, 35(4): 247-248. https://doi.org/10.3969/j.issn.1000-3428.2009.04.087With the high demand of communication bandwidth for multi-processor system, combining LocalLink protocol and Batcher-Banyan switching network, this paper proposes a dynamic interconnection network which is fit to be realized in FPGA. Compared with traditional interconnection, communication performance is improved great, while only occupying a small quantity of hardware resource. The network is also convenient to integrate with new communication interface, brings forward a high performance and flexible interconnection method for multi-processor system design.
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Computer Engineering. 2009, 35(4): 249-251. https://doi.org/10.3969/j.issn.1000-3428.2009.04.088The validity of System on Chip(SoC) depends on thorough verification. Efficient and reusable verification platform is necessary. The real-time and multi-task embedded operating system VxWorks is applied in this platform. It adopts unique memory mapping technique for convenient debug. Based on the interpretation of the BFM commands in AMBA VIP, this platform fulfils reusability of testcase. Through the bridge between AHB and EC, it is compatible in SoC based on AMBA bus or EC bus. This platform is applied in the verification of USIM IC which uses COS operating system.
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Computer Engineering. 2009, 35(4): 252-254. https://doi.org/10.3969/j.issn.1000-3428.2009.04.089According to the requirements of supreme people’s procuratorate for synchro audio-video supervise and record for whole process of trial, this paper researches and designs an audio-video supervise and record system for trial in procuratorate. This system uses the combination structure based on three level C/S and B/S, and realizes the key problems such as the synchronized audio and video record, the simultaneous burn of double DVD, the real-time supervising and control on Web during the trial process by the technologies of video-server, DLL component and ActiveX control based on COM, virtual real-time mechanism. It ensures the system’s security with the safety strategies including hardware-encryption and the role based access control.
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Computer Engineering. 2009, 35(4): 255-257. https://doi.org/10.3969/j.issn.1000-3428.2009.04.090According to the molecular evolution rule of Newcastle Disease Virus(NDV), a genotyping system of NDV based on Web is developed by using JSP and SQL server database technology. The system analyses and processes nucleic acid sequences automatically through computer program. It acquires the information of characteristic sites and compares them with genotyping standards, thus the system realizes accurate genotyping quickly, decreases the times of people participation, and shortens the period of genotyping. It has better practicability and expansibility.
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Computer Engineering. 2009, 35(4): 258-260. https://doi.org/10.3969/j.issn.1000-3428.2009.04.091For transforming statistical electronic map from desktop to Web-based platform, this paper designs an architecture and a series of methodology of a Web-based statistical map distributing system, and describes framework and key models of the system. Based on a desktop statistical map system, Electronic Atlas of Population, Environment and Sustainable Development of China (2005), a test system has been developed, and transforms more than 200 statistical maps for Web distribution. Through system test, the result shows that the design can fulfill smooth transformation from the desktop statistical map to the Web-based statistical map.
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Computer Engineering. 2009, 35(4): 261-264. https://doi.org/10.3969/j.issn.1000-3428.2009.04.092The traditional enterprise information integration is driven by function, which mainly solves the distributed and heterogeneous data integration problems, but without the consideration of the business logic, stepping strictly into the business integration level. If no actions are taken at the data integration level to response the enterprise business work flow, it restricts the system ability of sharing data. This paper provides a data cooperative model which is based on business logic of enterprise. It invokes the event which drives data flowing between different organizations. It is a loose coupling model and gives customer the ability to change functions and data transform rules. The system which changes a lot will benefit from the model.
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Computer Engineering. 2009, 35(4): 265-267. https://doi.org/10.3969/j.issn.1000-3428.2009.04.093By using shared memory, this paper designs the architecture of the battlefield situation simulation system supporting High Level Architecture(HLA) and puts forward the conception of snapshot, which eliminates the distinction between static and dynamic object at the logical level, and manages all the situation objects with the same memory structure. It discusses several key technologies on implementing the system, which includes the updating flowchart of simulation data, real-time interpolating of track data, visualization optimizing of dynamic layer. The system is feasible and logical in experiment and practice.
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Computer Engineering. 2009, 35(4): 268-270. https://doi.org/10.3969/j.issn.1000-3428.2009.04.094Tracking technique is one of the most important research fields in Augmented Reality(AR). It aims at solving accurate registration problems between virtual information and real environment and building a stable and effective AR system for practical use. This paper analyzes the tracking requirements for AR applications, describes the necessity of applying hybrid tracking techniques, and specifies a hybrid approach that integrates inertial (6-DOF) and vision-based tracking techniques in AR and its applications. A hand-held AR experimental system based on VisTracker and a hybrid vision-inertial self tracker are designed. Analysis and experimental results demonstrate the system’s effectiveness and its potential application in augmented museum tour system.
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Computer Engineering. 2009, 35(4): 271-273. https://doi.org/10.3969/j.issn.1000-3428.2009.04.095A polarization dehazing algorithm based on atmosphere background suppression is proposed, which makes use of polarization imaging detection system to achieve polarization images from all aspects. The atmosphere lumen outpout and the degree of polarization are estimated. The depth of scenery is also estimated by using the information of scenery polarization. The atmosphere scattering model is restored. Thus, the image dehazing is implemented. Experimental results show this algorithm improves scenery visual effect in condition of haze.
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Computer Engineering. 2009, 35(4): 273-275. https://doi.org/10.3969/j.issn.1000-3428.2009.04.096Considering the demand of communication between clinical laboratory instruments and computer system, this thesis studies the international standards ASTM E1381 and ASTM E1394, and puts forward a relatively common solution based on DCOM and ASTM, including multi-tier distributed application, ASTM communication implementation and sending/receiving data by multi-thread. The application accomplishes two-way information transmission between laboratory instruments with standardized interface and computer system. It not only can flexibly switch operation, but also is helpful to load balancing.
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Computer Engineering. 2009, 35(4): 276-277. https://doi.org/10.3969/j.issn.1000-3428.2009.04.097A kind of embedded fingerprint authentication and management terminal based on B/S structure is proposed. This terminal is established on S3C4510B microcontroller and uClinux operation system, and it can complete fingerprint collection, fingerprint authentication, fingerprint storage and fingerprint management. The hardware/software design and implementation of this terminal is also introduced.
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Computer Engineering. 2009, 35(4): 278-280. https://doi.org/10.3969/j.issn.1000-3428.2009.04.098Aiming at the problem that how to evaluate and survey the speech quality of VoIP accurately, this paper evaluates the speech quality of VoIP based on E-Model, analyzes the impact of several major factors such as time delay, and packet loss. It constructs a model which includes the factor jitter that is not considered in E-Model and analyzes the impact of jitter buffer on speech quality. Results of the designed experiments show that the precision of the model evaluating the speech quality of VoIP is satisfied.
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Computer Engineering. 2009, 35(4): 281-282. https://doi.org/10.3969/j.issn.1000-3428.2009.04.099Antiaircraft artillery is the important weapon equipment in air defense and the important constitute part in air defense system. Based on the characteristics of gun unit, this paper presents a method of war gaming system for gun unit and architecture depending on High Level Architecture(HLA). It researches method of design of fire control system. A system is developed to validate the feasibility of this scheme. It can be used to study and assess the tactics of air defense, and the effectiveness of combat and operation.
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Computer Engineering. 2009, 35(4): 283-封三. https://doi.org/10.3969/j.issn.1000-3428.2009.04.100The embedded system used in military fields, space fields and like needs more flexibility, reliability and controllability. This paper proposes Reconfigurable Parallel Embedded System(RPES) architecture. RPES supportes parallel and demoting processing. It can change the software and data in EEPROM dynamically. Its accelerating unit can support dynamic reconfiguration. The test result shows that RPES can give strong support for the fault-tolerant method and gains the performance in the system.
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