20 October 2007, Volume 33 Issue 20
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Computer Engineering. 2007, 33(20): 1-3,7. https://doi.org/10.3969/j.issn.1000-3428.2007.20.001In clock routing, clock signal and clock skew become more and more important for impact of the circuit performance. Due to the shortcomings of traditional topology construction algorithm for clock network, multi-level model of clock binary tree and binary tree construction algorithm of clock signal based on simulated annealing are presented. The test results for random test cases and standard benchmark test cases by this algorithm show that this algorithm can produce much better test results compared with traditional heuristic algorithms.
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Computer Engineering. 2007, 33(20): 4-7. https://doi.org/10.3969/j.issn.1000-3428.2007.20.002
This paper proposes a new tree-based Internet accelerator(TIA), and analyzes the key techniques of the accelerator, such as enlarging the query scope, enhancing layer-connections, using dynamic parents and quick locating of objects. A meta-algorithm to improve hierarchical caches performance is researched. A stable network accelerator system is designed and implemented, and the trace-driven experiments show that the new TIA has a good accelerating rate.
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Computer Engineering. 2007, 33(20): 8-11,1. https://doi.org/10.3969/j.issn.1000-3428.2007.20.003As a key technology to reduce DNS resolution time, DNS performance optimization becomes a heated research issue. This paper proposes failed TTL-based renewal policy, which attains quicker query speed. Compared with traditional server of DNS, the accelerator of DNS is good at cache hit-rate, network traffic, CPU load and query-response time by the performance test of the concrete website, which achieves good performance.
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Computer Engineering. 2007, 33(20): 12-14. https://doi.org/10.3969/j.issn.1000-3428.2007.20.004
For reducing the “triangle routing” problem in mobile network, a dynamic home agent is introduced to provide local home agent service for the mobile network in the foreign mobile network. A dynamic home agent model based on the AAA scheme is designed, and a mobile network registration and key exchange protocol based on the digital signature scheme and the Diffie-Hellman key exchange algorithm is realized, and the data route method of mobile network nodes is described. The security analysis shows that the presented protocol can realize the key exchange between mobile router and the dynamic home agent securely, defending the man-in-the-middle attacks and session hijacking attacks, and traces the mobile node which commits flooding attack.
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Computer Engineering. 2007, 33(20): 15-17. https://doi.org/10.3969/j.issn.1000-3428.2007.20.005Two main phrases of the compiler of the parallel machine are the code partitioning to abstract parallelism and the scheduling phrase. There are many more solutions to the scheduling phrase in the literature, but few regards the code partitioning phrase. A novel adaptive algorithm for code partitioning which merges points to partition the directed acyclic graph (DAG) is presented. It has been proved through the case that the algorithm is an efficient and low complexity solution for code partitioning. It is also suitable to the task graph partitioning for heterogeneous computing.
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Computer Engineering. 2007, 33(20): 18-20. https://doi.org/10.3969/j.issn.1000-3428.2007.20.006To realize dynamic load balance in homogeneous multiprocessor system, several rules are proposed and used to restrict the process of searching lightly loaded processor. A dynamic load balancing algorithm, which can fast distribute redundant loads, is distributed control and sender initiated, is proposed. Experiments prove the algorithm’s validity in dealing great scale compute intensive task.
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Computer Engineering. 2007, 33(20): 21-23. https://doi.org/10.3969/j.issn.1000-3428.2007.20.007According to the difference of computing capability in mobile commerce, a new effective digital signature protocol aimed at digital images is put forward. Its basic thought is to send divided message to third party server and finish the digital signature, then the middle result is sent back to mobile devices to be made up. Operation process of this protocol is described, and its performance in improving the speed is analyzed, then the security ability toward various networks attack and accidents is demonstrated. Theory proves this protocol can solve the problem of different computing capability in mobile commerce, and guarantee the communication security.
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Computer Engineering. 2007, 33(20): 24-26,3. https://doi.org/10.3969/j.issn.1000-3428.2007.20.008A new transport framework of RTP/SCTP/IP is presented for adapting to the time-variable Internet and enhancing the reliability of transport. An improved simplified PFGS coding framework, using the standard of H.264 in base layer of PFGS, is adopted on source terminal. The steam of PFGS is separated for many sub-flows to transport by the characteristics of SCTP multi-streaming for improving the reliability and flexibility of transmission. A transport method that is a finite state machine(FSM) framework based on network bandwidth prediction over the Internet is presented. Simulation results show that this scheme can highly improve the quality of video and obtain a gain of about 0.5dB～1.5 dB in PSNR compared with the traditional network framework. Ability of adapting to network and reliability of transmission are improved rapidly.
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Computer Engineering. 2007, 33(20): 27-29,3. https://doi.org/10.3969/j.issn.1000-3428.2007.20.009Symbolic simulator assigns symbolic variables to the inputs of both specification and implementation, propagates those to the outputs, builds the symbolic expressions for both circuits, and checks the corresponding signals. The paper introduces the history, basic technology, and the drawback of BDD blowup of symbolic simulation. The two techniques, approximate value method and parametric method, which are used to eliminate the BDD blowup problem, and symbolic trajectory evaluation(STE) is also introduced.
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Computer Engineering. 2007, 33(20): 30-33. https://doi.org/10.3969/j.issn.1000-3428.2007.20.010A modal logic based on belief, MBL logic, is introduced to analyze security of authentication key-exchange protocols with one-way functions. The logic has following characteristics: it has a rational proof system and its inference rules can be proved right under its own semantic model. It can analyze authentication of messages protected by one-way functions, and analyze whether messages are kept secret. Through these rules, analyzer could reduce the dependency on trusted third part about the security of temporary session key, and be able to find whether adversaries could make effective attacks on protocols through cheating trusted third part.
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Computer Engineering. 2007, 33(20): 34-36,3. https://doi.org/10.3969/j.issn.1000-3428.2007.20.011To overcome the defects of image segmentation by classic fuzzy C-means (FCM) clustering that considers nothing about image continuity, this paper introduces a new spatially constrained FCM image segmentation algorithm. The pseudo-likelihood of labeling is adopted in this algorithm to combine spectral similarity and spatial neighboring of image pixels. A new objective function is proposed and minimized. The experiments are conducted on simulated gray images and real color images. Experimental results show that the proposed approach is more effective and has better performance.
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Computer Engineering. 2007, 33(20): 37-39. https://doi.org/10.3969/j.issn.1000-3428.2007.20.012Context information describes the details of entity and situation. This paper introduces a comprehensive and formal ontology-based model and reasoning mechanism. The implementation of context ontology enhances the expressiveness, support inference, thus can improve the management of context information. The key method, supportive tools and prototype systems are introduced. The main benefit of this model is the ability to reason over context data by two ways: description logics and rules, which can improve the context information management.
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Computer Engineering. 2007, 33(20): 39-51.The paper analyses the relations between entities and activities based on enterprise subject databases, and proposes the affinitive degree and the polymeric degree for entities based on active-entity relations to create the polymeric degree matrix. According to the sizes of entity polymeric degrees, the method for dividing subject databases is presented to obtain the core entity pair, which is used to polymerize the same entity between the other second entity pair and the core one. The entity pair is calculated with weighted polymeric degrees to divide into some subject databases based on the core entity pairs. The example compares the calculation results of the affinitive degree matrix and the polymeric degree matrix, which shows that it is distinctly reflect the affinity and the trend among entities by creating subject databases based on the polymeric degree matrix.
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Computer Engineering. 2007, 33(20): 40-42. https://doi.org/10.3969/j.issn.1000-3428.2007.20.013This paper presents an efficient algorithm for alpha estimation based on perceptual color space in natural image matting. A user specifies a trimap which partitions an image into definitely foreground, definitely background and unknown. For each pixel in the unknown region, the algorithm separates intensity and chroma information from RGB color after its foreground and background color components are estimated. Alpha component is decomposed into intensity part and chroma part. The weighted mean of these two parts yields the final alpha value.
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Computer Engineering. 2007, 33(20): 43-45,4. https://doi.org/10.3969/j.issn.1000-3428.2007.20.014In order to solve the interaction coupling caused by sharing data between software modules effectively, a new design pattern is presented named registry pattern. This pattern encapsulates the sharing data, avoids the data transfer between each module, separates the data providers and the data accessors, realizes one kind of simplified access protocol between the objects, and ultimately reduces the degree of modules’ coupling. The theory and the practice proof that registry pattern is effective for the object-oriented design, which is component, or module based software architecture.
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Computer Engineering. 2007, 33(20): 46-48. https://doi.org/10.3969/j.issn.1000-3428.2007.20.015Virtual organization model is an agent cooperation model presented in the research of e-business. Web services technology provides a mechanism to support cooperation and collaboration of multi agents. A framework for multi-Agent system management and communication is presented, called In-Agent, which is based on virtual organization model and Web services technology. In-Agent uses UDDI as its register center to manage agent register information, and uses SOAP as its communication tool to transfer information between agents. In-Agent also provides toolkits for system management and monitoring. With In-Agent, developing and deploying a multi-Agent system is more convenient.
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Computer Engineering. 2007, 33(20): 52-54,5. https://doi.org/10.3969/j.issn.1000-3428.2007.20.017This paper focuses on the environmental acoustic effect simulation and related technologies, and an environmental acoustic effect simulation system based on acoustic measurement modeling method is developed. In order to get the model of environmental acoustic effect in a room, assuming the model is linear and recognizing the impulse response of the model using correlation analysis method. The Interpolation technique in frequency domain is employed to calculate the room impulse response in the given condition. The software architecture, main modules and key technologies of the system are also presented. Experimental results demonstrate that the system can well simulate room environmental acoustic effect. The system can be applied to various virtual reality systems.
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Computer Engineering. 2007, 33(20): 55-57. https://doi.org/10.3969/j.issn.1000-3428.2007.20.018The sensor failure management is one of the important tasks of the sensor management system, which is under hot discussion. Aiming at the sensor failure management method based on fuzzy logic, this paper, through computer simulation, analyzes the influence of different fuzzy membership function on the sensor failure management. The simulation results show that the methods based on fuzzy logic can satisfy the requirements of the sensor failure management, and reduce the data fluctuate and the error of sensor management system.
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Computer Engineering. 2007, 33(20): 58-60,6. https://doi.org/10.3969/j.issn.1000-3428.2007.20.019It is the resources that execute the business process, WFMS just acts as an organizer. Workflow resource management(WFRM) focuses on rule definition of task allocation and distributive operation in operation environment, and transfers the results to proper executive resources. Based on the principle of task-oriented collaboration, this paper analyzes the domain of WFRM, discusses problems of it to a certain extent.
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Computer Engineering. 2007, 33(20): 61-63. https://doi.org/10.3969/j.issn.1000-3428.2007.20.020Whether an e-mail is a legal one or not, different users hold different opinions. As a result, research of e-mail filtering should be considered as dealing with the uncertainties. This paper proposes an integrated method of ordered weighted averaging(OWA) operator and fuzzy support vector machines(FSVM). Its main idea is to obtain a reasonable value of comprehensive evaluation as each mail’s membership degree by using the OWA operator method, then classify each mail though FSVM. Simulative experiments are conducted to verify the effectiveness of the method.
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Computer Engineering. 2007, 33(20): 64-66,6. https://doi.org/10.3969/j.issn.1000-3428.2007.20.021Based on Globus MDS4 monitoring system, this paper proposes an open and extensible monitoring information model, on which a persistent function is added, service for collected monitoring information is offered, and a grid database performance monitoring system——DBMg is implemented. Experimental results show DBMg is a powerful monitor tool for fault diagnoses, performance adjustment, performance optimization with minimum impact on the database.
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Computer Engineering. 2007, 33(20): 67-69. https://doi.org/10.3969/j.issn.1000-3428.2007.20.022Against the low efficiency in identifying tags by EDFSA and a demand for testing the precise location of anti-collision by binary tree search, a novel anti-collision algorithm based on Hash-tree is presented. By analyzing key problems of the algorithm and making a strategic plan for it, rate of identifying tags with the algorithm is expected to reach between 36.8% and 1, which outperforms EDFSA. Simulation results show that the algorithm is outstanding in tag identification, especially when dealing with large amounts of tags.
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Computer Engineering. 2007, 33(20): 70-71,7. https://doi.org/10.3969/j.issn.1000-3428.2007.20.023In the mining methods of association rules, itemset with high-length usually have lower support, but still have potential value. To efficiently mine association rules with long-pattern, a length-decreasing support constraint is proposed. This paper uses vector to mine association rules under this constraint. Compared to other mining methods of association rules, the new method can mine more efficacious long-pattern, reduce many unnecessary short-pattern and improve efficiency of mining association rules.
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Computer Engineering. 2007, 33(20): 72-74. https://doi.org/10.3969/j.issn.1000-3428.2007.20.024This paper discusses workflow system based on multi-agent and lightweight design idea, proposes the representation of the way to implement the workflow system, methods of task decomposition and resource assignation. A method based on ontology is proposed and discussed for information transfer among agents in workflow system. The method lessens the communication burden of the workflow system, analyzes function of this architecture, shows the superiority of the model, and introduces implementation scheme.
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Computer Engineering. 2007, 33(20): 75-77. https://doi.org/10.3969/j.issn.1000-3428.2007.20.025Service creation is an important technology for various value-added services provision in NGN. Model driven architecture(MDA) is an advanced software development methodology. In order to enhance the reusability and technical neutral of service logic model, one model-driven convergent service creation approach is presented by applying MDA technology. The key theory and technologies involved are addressed. The method enhances the abstraction level of service development and the reusability of application. l
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Computer Engineering. 2007, 33(20): 78-79,8. https://doi.org/10.3969/j.issn.1000-3428.2007.20.026This paper introduces the technology of event-driven distributed workflow and extends ECA rule in time to resolve the problems of ECA rule in describing complex process related to time. It rewrites the event into the occurrence time of the event to make the event express semantic better. This technology is applied in the design of a container logistics information system(CLIS). Working process of the whole container logistics is built, and the implementation of a process instance is described.
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Computer Engineering. 2007, 33(20): 80-82. https://doi.org/10.3969/j.issn.1000-3428.2007.20.027The primary medicine analysis of traditional Chinese medicine(TCM) is studied with data mining technology. The main contributions include the proposal and implementation of a primary medicine mining algorithm based on multidimensional-data analysis, with which the disturbance medicine is filtered out and TCM couples are identified. Extensive comparison experiments using spleen-stomach recipe data show that the algorithm is superior to the one based on relative dosage. The algorithm can improve the correct rate of primary medicine analysis effectively.
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Computer Engineering. 2007, 33(20): 83-85. https://doi.org/10.3969/j.issn.1000-3428.2007.20.028To meet the application requirement, this paper constructs a data replication system among network databases. After analyzing the limitation of providing data in OGSA-DAI, Session mechanism is utilized to improve the capability of providing continuous data in OGSA-DAI. This paper describes the key techniques for implementing data monitoring and session pool. An example is given to demonstrate the execution process of data publishing in the system.
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Computer Engineering. 2007, 33(20): 86-88. https://doi.org/10.3969/j.issn.1000-3428.2007.20.029This paper presents a transaction model for grid and a grid timestamp concurrency control (GTCC) protocol supporting this model. The GTCC extends the transaction type and lessens the range of transaction conflict to avoid a large number of transaction restart and increase transaction concurrency degree. The correctness of GTCC protocol is proved, and experiment results in a prototype system show that the protocol is feasible and effective.
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Computer Engineering. 2007, 33(20): 89-90,9. https://doi.org/10.3969/j.issn.1000-3428.2007.20.030In order to improve the performance and the QoS of Apache server constantly, an adaptive tuning mechanism for Apache based on real time monitoring is introduced, which uses an analytic performance model combined with combinatorial search techniques to complete some tuning tasks as the workload changing. A model with this mechanism is designed into Apache, and the function of each module, the technology and algorithm of model is depicted. An experiment is conducted for evaluating the efficiency of this mechanism.
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Computer Engineering. 2007, 33(20): 91-93. https://doi.org/10.3969/j.issn.1000-3428.2007.20.031Management of dynamic memory is a very important task of computer science. This paper proposes a new arithmetic of memory management based on two classical arithmetic. By absorbing soul of classical arithmetic and improving their shortcoming, it makes the new arithmetic fit the special requirement of embedded system.
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Computer Engineering. 2007, 33(20): 94-96. https://doi.org/10.3969/j.issn.1000-3428.2007.20.032In order to match resources more efficiently, this paper puts forward some improvements of semantic Web technologies and matching algorithm. It extends OWL-S to suit grid ontology and introduces semantic description format for grid services so that agent technology can be involved. Domains of service registers and service requests are defined, and services matching is completed in the specific domain. It also presents a framework structure called grid services matching framework based on semantics (GSMFS), which includes services request, services register and services matching. Functions and characteristics of key components are illuminated. By prototype implementation of the framework, it is proved logical and right.
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Computer Engineering. 2007, 33(20): 97-98. https://doi.org/10.3969/j.issn.1000-3428.2007.20.033This paper introduces a Web filtering method based on the combination of manual Web mining and URL. Using Web mining to achieve content-based Web categorization offline, it overcomes the limitation of key words filtering system and URL filtering system. Experimental results show that recognition of Web classification with the method is acceptable, which enjoys practical value.
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Computer Engineering. 2007, 33(20): 99-100,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.034As direct access to memory(DMA) is widely used in the high speed network interface card (NIC) design, the DMA engine has become one important component of the high speed NIC. This paper presents the implementation method of the DMA engine in the high speed NIC. This method is used successfully in the 1 000Mb/s Ethernet NIC.
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Computer Engineering. 2007, 33(20): 101-103. https://doi.org/10.3969/j.issn.1000-3428.2007.20.035With the deepening information construction and enlarging Web scale, it is difficult to judge the problem of network performance and failure, thus the demand of network management software becomes more urgent. However, there are many problems existing in current network management software, such as high price, difficult implementation etc.. In order to solve these problems, this paper develops an embedded network management alarm system, which can be implemented expediently in crucial network environment, inform network administrator alarm information by short message. The future research aspect about the system is given.
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Computer Engineering. 2007, 33(20): 104-106. https://doi.org/10.3969/j.issn.1000-3428.2007.20.036In collaborative virtual environment (CVE) systems based on multiple-server architecture, since the random movement of avatars causes the imbalance of load among the servers, the system capability will be declined when some servers are overloaded. In active dynamic load balancing algorithm, the control rights of some users with the large value of interest membership degree are transferred to other servers in the neighborhood in order to efficiently assign avatars to the servers in the operating system when a server has the overlarge computing cost or communication cost or the load of a server is close to saturation. The experimental data shows that the method can balance the load among the servers, so it can improve the scalability and quality of service of the CVE systems.
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Computer Engineering. 2007, 33(20): 107-109,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.037In order to adapt to the complicated mobile multicast environment, this paper brings forward a priority-based datagram management mechanism which endues different datagram with different priorities, and advances an adaptive mobile multicast protocol for the network based on the hierarchical architecture. Adopt bi-directional tunneling mechanism in the subnet and adopt the integration of bi-directional tunneling and remote subscription in the region. The protocol can deliver the datagram reliably and efficiently, and it also can get a balance between the shortest delivery route and the reduction of multicast tree’s reconstruction cost.
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Computer Engineering. 2007, 33(20): 110-112. https://doi.org/10.3969/j.issn.1000-3428.2007.20.038This paper proposes a set of traffic metrics of ATM network. A traffic measurement and analysis system is developed based on C-5 network processor. The system can perform VPI/VCI utilization measurement, real-time reassembly of data received over ATM network and higher level protocol analysis. Experiments with operated network and instrument show that the system can parse traffic at OC-12 with the cell loss rate less than 0.001%.
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Computer Engineering. 2007, 33(20): 113-115,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.039In real-time multimedia applications, multicast, especially the demand of delay constraint from source to destination end during information transmission, is required. This paper concentrates on multicast routing problem with end-to-end delay bounded. Based on the original algorithm which constructs the delay-constrained path from source end to destination end, this paper presents an algorithm to solve DMR (delay-constrained multicast routing) problem. The algorithm can construct delay-constrained multicast tree efficiently. Theoretical analyses indicate the time complexity of the algorithm is the same as that of CDKS. Besides, simulation results prove that this algorithm can construct a multicast tree whose cost is lower than CDKS.
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Computer Engineering. 2007, 33(20): 116-118. https://doi.org/10.3969/j.issn.1000-3428.2007.20.040According to the characteristics that the network flow statistics show a strong heavy-tail distribution, this paper puts forward a method using Sample-CBF to realize elephant flows identification, which combines period sampling and counting bloom filter(CBF) technique. According to the different sampling strategies, the method is translated into two specific methods: PSample-CBF method and FSample-CBF method. Theoretical analysis and simulation result indicate under the condition of existing some tolerable measurement error about the length of flows, the two methods both can identify elephant flows accurately, reduce the storage space and improve the processing speed efficiently.
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Computer Engineering. 2007, 33(20): 119-121. https://doi.org/10.3969/j.issn.1000-3428.2007.20.041In Ad Hoc access networks, Ad Hoc nodes communicate with the correspondent nodes in the backbone networks via the foreign agent. One of the key components affecting the overall performance of Ad Hoc access networks is the algorithm used to select foreign agents. Since Jelger algorithm has the defect of frequent handoffs and more average hops, an improved algorithm based on hops and route stability is proposed. Compared with Jelger algorithm, the proposed algorithm can remarkably decrease the handoff times and average hops to the foreign agents. Additionally, it has lower and more stable packets lost ratio.
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Computer Engineering. 2007, 33(20): 122-124. https://doi.org/10.3969/j.issn.1000-3428.2007.20.042Aiming at the instability of Internet remote control system with variation time-delay, a novel delay prediction method based on wavelet-ARMA technique is designed to solve the problem caused by Internet-induced time delays in an Internet remote control system. Simulation results show that the method combined with Smith prediction is able to keep the Internet remote control system with good stability and dynamic performance. The availability and effectiveness of the method are verified by the usage of DC motor.
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Computer Engineering. 2007, 33(20): 125-127,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.043This paper presents implementation of mobile IPv6 in distributed router. Taking both function requirement of MIPv6 protocol and structure of distributed router, the fast channel MIPv6 solution and the slow channel MIPv6 scheme are proposed, both their advantage and disadvantage are compared. The slow channel MIPv6 scheme is tested. Test results show that the slow channel MIPv6 scheme ensures router perform mobile IPv6 function simply and credibly.
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Computer Engineering. 2007, 33(20): 128-130. https://doi.org/10.3969/j.issn.1000-3428.2007.20.044How resources are organized and how messages are routed through the network affect the quality of resource discovery in grid. New ideas are introduced to grid with the development of P2P system. This papers introduces the concept of virtual organization(VO), and divides resources into many VOs according to their types. It presents a layered resource management architecture called C&G, and presents three algorithms for resource management in P2P layer: IE(information exchange), ID(information discovery) and IR(information routing). Compared with traditional algorithms through simulation test, the performance can be improved.
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Computer Engineering. 2007, 33(20): 131-133. https://doi.org/10.3969/j.issn.1000-3428.2007.20.045Aiming at the characteristics that active network executes active codes and processes capsule, this paper proposes a multi-priority shortest packet first scheduling mechanism. This scheduling mechanism consists of capsule classifier, buffer manager, buffer queues and queue scheduler. Capsule classifier classifies arriving capsule according to promissory rules. Buffer manager sends capsule to corresponding queue according to its priority and insert it to appropriate place of queue keeping to sequence. Buffer queues store capsules. Queue scheduler controls capsules from relative-priority and latency. Experimental results show that this scheduling mechanism accords with characteristics of active network, it can fast and effectively schedule capsule in active network.
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Computer Engineering. 2007, 33(20): 134-136,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.046One problem of simultaneous mobility is that messages, especially protocol messages, are lost during simultaneous mobility, which leads to the interruption of communication. This paper analyzes the problem for MIPv6 and some current solutions, and proposes multi-binding solution based on home agent. Simulations shows that the scheme can resolve such problem effectively and efficiently.
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Computer Engineering. 2007, 33(20): 137-138. https://doi.org/10.3969/j.issn.1000-3428.2007.20.047This paper describes a model of automatic generation and reduction of security protocols. In the first stage, based on the system specification, it generates candidate protocols and reduces these protocols with syntactical restriction rules and early-pruning by simple impersonation attack. In the second stage, it optimizes the protocols by reduction techniques based on strand space model and gains the optimal protocols.
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Computer Engineering. 2007, 33(20): 139-141. https://doi.org/10.3969/j.issn.1000-3428.2007.20.048Pseudo-random number generator based on the traditional characteristic polynomial and the register has disadvantages of slow speed, high cost and short life cycle. A compound chaos system is designed using non-linear logistic mapping system and the partition mapping. A production algorithm of pseudo-random number generator based on the compound non-linear chaos system is introduced. Theoretical and experimental results show that the random sequences produced by this pseudo-random number generator has good cryptology performance, making the design an ideal pseudo-random number generator. A new chaos stream cipher encryption system is designed based on the algorithm. It can resist end computation and statistics attacks. Experimental results show that this stream cipher is desirable in terms of security, cost-effectiveness and pseudo-randomness.
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Computer Engineering. 2007, 33(20): 142-144,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.049Fuzzing is an automated vulnerability exploiting technique. This paper propose a vulnerability exploiting approach based on Fuzzing and applies the approach to TFTP protocol. A fuzzer named tftpServerFuzzer is designed and implemented to test TFTP servers. 11 types of TFTP servers based on Windows via Internet are collected. By testing those TFTP servers using tftpServerFuzzer, seven unreleased and six known vulnerabilities are discovered. The result indicates the validity and superiority of the tftpServerFuzzer.
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Computer Engineering. 2007, 33(20): 145-147. https://doi.org/10.3969/j.issn.1000-3428.2007.20.050The Windows RDP protocol developed by Microsoft Inc. has caused many security problems. The principles of RDP are introduced, and the security-mechanism adopted by RDP is also analyzed. It points out some improper design methods of the protocol. Some security improvement schemes of RDP protocol and advices for using RDP application are both offered.
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Computer Engineering. 2007, 33(20): 148-149,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.051RSA is a very important public-key encryption algorithm. The bottleneck problems of RSA efficiency are big prime number finding and exponential modular computation. RSA key-pair generation depends on the two problems mentioned just now. This paper carefully analyse the main algorithms used by the key-pair generation process, and improves the preselection algorithm by modifying the method of random number generation.
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Computer Engineering. 2007, 33(20): 150-152. https://doi.org/10.3969/j.issn.1000-3428.2007.20.052The paper analyzes the method that correlates alerts on the basis of prerequisites and consequences. Then it proposes a method for constructing attack scenarios based on system vulnerabilities and alert relativity. It not only can validate the reliability of alerts through system vulnerabilities, remove false positives, but also can correlate attacks including many steps through alert relativity. The experiment results have demonstrated that the proposed approach can decrease false positives and false negatives effectively. It can help to construct more authentic and integrated attack scenarios.
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Computer Engineering. 2007, 33(20): 153-155. https://doi.org/10.3969/j.issn.1000-3428.2007.20.053UMTS is one of the most important networking technologies of the third generation mobile communication system. Security in UMTS core network is lack of attention, and no integral security architecture is defined. To solve this problem, security of the third generation communication system is analyzed, and security architecture applied to 3GPP UMTS core network is proposed. This architecture provides a basis to security study of 3G core network in future.
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Computer Engineering. 2007, 33(20): 156-158. https://doi.org/10.3969/j.issn.1000-3428.2007.20.054Based on the trusted computing group (TCG) specifications about trusted computing, a new type of flexible trusted PC (FTPC) is developed. The model and the trust transitive mechanism of FTPC are discussed. The trusted platform module (TPM) is an extension of USB port, and the legacy BIOS is enhanced to be the core root of trust for measurement (CRTM) in FTPC. The technologies, such as identity authentication of entity, integrity measurement of entity, and sealed storage, are employed in FTPC to support trusted computing. Without changing the PC’s current hardware architecture, the FTPC is more easy and flexible to be implemented and applied than the TCG trusted PC.
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Computer Engineering. 2007, 33(20): 159-161. https://doi.org/10.3969/j.issn.1000-3428.2007.20.055The identity authentication using public-key certificate based on asymmetric key has a great number of disadvantages, for example, the PIN can be forgotten or stolen and can be easily cracked. Biometric authentication, being an accurate, fast and efficient authentication method, is being more and more widely used in identity authentication field. Based on PKI, this paper proposes telebiometric authentication infrastructure, which provides an integrated biometric authentication scheme.
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Computer Engineering. 2007, 33(20): 162-164. https://doi.org/10.3969/j.issn.1000-3428.2007.20.056This paper points out the issues which should be considered when a chaotic cryptosystem is designed. A block encryption algorithm based on multiple logistic maps is proposed. Owing to the multiple chaotic maps, the key space of cryptosystem is extended. With the ciphertext feed back, the subkey sequences is generated from the chaotic maps. The subkey sequences have good uniform distribution property, random statistical property and have relation to the plaintext, which enhance the security of the cryptosystem. Theoretical study and computer simulation results show that the cryptosystem has a high speed and good security.
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Computer Engineering. 2007, 33(20): 165-166,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.057The security of a chaos sequence-based image encryption and decryption algorithm is analyzed. The encryption algorithm is a shift cipher essentially and its key space is too small. The chaotic sequence is obtained by using the analysis method of shift cipher of classical cipher. A known plaintexts attack is proposed by exhaustive parameter search. For a M×N plain image, the computing complexity is O(M+N). From the analysis in theory and experimental results, this image encryption algorithm is proved insecure.
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Computer Engineering. 2007, 33(20): 167-169. https://doi.org/10.3969/j.issn.1000-3428.2007.20.058The blind watermark algorithm based on SVD proposed manipulates vertex’s geometric features, which can be used in meshes with any topological connectivity. SVD is processed in a 2D mapping grid, which is produced by vertex’s spherical coordinates and has similarly local statistical property of original mesh. Watermark sequence is embedded in singular value sequence. Experimental results show the algorithm can resist translation, rotation, uniformed scaling, vertex reordering, and is also robust against adding noise.
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Computer Engineering. 2007, 33(20): 170-172. https://doi.org/10.3969/j.issn.1000-3428.2007.20.059This paper presents an encrypted multi-component management model for software rights protection under limited hardware resource environment. Downloading, updating and deleting the encrypted multi-component are realized through combining virtual machine (VM) technology and layered function strategy. The security measures adopted in this model are put forward. The model is of high security and good platform portability, and is equipped with software development mode supporting multi-participation.
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Computer Engineering. 2007, 33(20): 173-175. https://doi.org/10.3969/j.issn.1000-3428.2007.20.060This paper analyzes the security threats of the immune IDS schemes and the useful metaphor of biological immune system considering whose application in the study of IDS. In light of the system flaws arising from the transfer of disease-causing mechanisms of biological immune system into IDS, an algorithm for optimizing measure parameters based on genetic algorithm and biological immunology is designed together with a hybrid intrusion detection engine. The scheme precludes the security problems by utilizing the useful metaphors of biological immunity and the prominent characteristics of genetic algorithm. It is characterized by parallel operating, stability, adaptability and robustness. The paper justifies its brevity, security, high efficiency.
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Computer Engineering. 2007, 33(20): 176-177,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.061This paper provides a systematic analysis for the security of an evolutionary cryptosystem by the correlation of the key output sequence. The analysis result is as follows: if continuous 128 bits of the key output sequence are known, the key space scale of the cryptosystem decreases from 2256 to 2128. If continuous 256 bits of the key output sequence are known, the key space scale of the cryptosystem decreases from 2256 to 284, moreover, the key space scale of the cryptosystem decreases to 272 under the condition that the number of error equations is no more than 4. The result shows the evolutionary cryptosystem is very insecure under chosen-plaintext attacks.
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Computer Engineering. 2007, 33(20): 178-180. https://doi.org/10.3969/j.issn.1000-3428.2007.20.062This paper studies the common hardware architecture of encryption network card. According to complex control and difficult design of stream architecture, it brings forward a multiple hardware architecture, which reduces the design difficulty and the control complexity, and designs the prototype card of encryption network card based on this architecture. A lot of data test shows the whole architecture achieves a good balance between performance and efficiency.
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Computer Engineering. 2007, 33(20): 181-183. https://doi.org/10.3969/j.issn.1000-3428.2007.20.063Trojan horses design essence lies in hijacking execution routine, and most of current detection methods fail to completely identify such ever-increasingly covert Trojan horses. The paper presents an approach to detect the existence of system call hooks set by Trojan horses based on the locality and determinacy of execution flows, and the analysis of system function call labs in both user and kernel levels, then designs and realizes corresponding prototype. Compared with current detections, the method offsets the deficiency in identifying unknown Trojan horses with more complete detection results.
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Computer Engineering. 2007, 33(20): 184-186. https://doi.org/10.3969/j.issn.1000-3428.2007.20.064In order to exhibit internal details of a model, it needs to process 3D model’s analysis such as cutting, digging and so on. This paper, based on spatial triangle network cutting algorithm——TriCut, brings out a new algorithm to create single block’s planar section. This algorithm can realize automatic, quick and exact creation of complex block’s planar section. And based on this algorithm, arbitrary incision analysis function of geological model is finished which includes creating 3D section chart and bar chart, digging pit, tunnel modeling and so on.
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Computer Engineering. 2007, 33(20): 187-189. https://doi.org/10.3969/j.issn.1000-3428.2007.20.065Data input excessively dependes on the customer’s evaluation of the personalization recommendation system in E-commerce. For resolving the problem, this paper proposes a framework for the recommendation system by considering the steps of case-base reasoning method, analyzes the key techniques of framework. An example is given to describe the application process of the CBR approach in the personalized recommendation system. The framework improves the effectiveness and accuracy of the recommendation system.
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Computer Engineering. 2007, 33(20): 190-192. https://doi.org/10.3969/j.issn.1000-3428.2007.20.066This paper proposes an automatic negotiation algorithm based on co-evolutionary algorithm, and simulates the strategy learning mechanism in the finite horizon alternating offer negotiation protocol. Experimental results indicate that the automatic negotiation based on co-evolution can produce the approximate strategy profile as that of the sub-game perfect equilibrium, and has a good prospect of application.
automatic negotiation; co-evolution; genetic algorithm; alternating offer
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Computer Engineering. 2007, 33(20): 193-195,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.067This paper analyzes the current research situation about building supply chain performance evaluation system and points out some problems. With the service performance system in retailer supply chain as an example, it introduces a new research method——Multi-agent System. The method takes the dynamic and complexity in supply chain into consideration which should obtain better performance in the future supple chain.
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Computer Engineering. 2007, 33(20): 196-198. https://doi.org/10.3969/j.issn.1000-3428.2007.20.068This paper establishes the Bernoulli statistical model of match simulation experiments, estimates match probability calculation formula of image matching algorithm based on estimation method. With unbiasedness proved, it analyzes precision, describles probability distribution model of successful match in serial image match, and gives the definition of SIM algorithm match probability. The quantitative relationship among SIM probability, image serial number and single match probability is studied by an application example, which provides a theoretical decision-making basis for the choice of SIM algorithm and serial image number in aircraft scene match guidance using SIM technique.
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Computer Engineering. 2007, 33(20): 199-200,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.069Searching for the shortest path is not only a hot issue in path analysis, but also an important functions and a key technology in logistics transportation system. Current solutions to the shortest path problem are mostly based on Dijkstra algorithm. On the basis of analysis and research of Dijkstra algorithm and its application, this paper launches a new solution which does not depend on the forming of static graph structure, but applies the idea of set calculation to get the set which meets the requirement of terms through gradually reducing the range of set by term restriction. Data storage structure consistent with the solution is launched. The search for the shortest path is accomplished in the application of the solution in the third party’s logistics transportation analysis system.
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Computer Engineering. 2007, 33(20): 201-203. https://doi.org/10.3969/j.issn.1000-3428.2007.20.070Abnormality detection plays an important role in dead-reckoning, locating, navigating and safety for wheeled mobile robots(WMRs). Based on the mobile robot developed independently by ourselves, this paper analyzes 4 kinds of states (i.e. normal, slipping, blocked, deadly stuck ) for driving wheels, extracts 8 kinds of features, recognizes state of motion, designs two strategies to avoid blocked or deadly stuck situations. Experimental results show that the method can identify different movement states and recover from the abnormality correctly and timely.
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Computer Engineering. 2007, 33(20): 204-206. https://doi.org/10.3969/j.issn.1000-3428.2007.20.071A new infrared and visible image sequences fusion scheme based on region target detection is proposed. Target detection technique is employed to segment the source image sequences into target and background regions. Different fusion rules are adopted respectively in target and background regions. The dual-tree complex wavelet transform(DT-CWT) method is introduced to achieve shift invariant multi-resolution representation of each source images. Fusion experiments on real world image sequences indicate that the proposed method is effective and efficient, which achieves better performance than the generic fusion method.
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Computer Engineering. 2007, 33(20): 207-209. https://doi.org/10.3969/j.issn.1000-3428.2007.20.072This paper proposes a new rolling algorithm for path plan of mobile robot based on genetic algorithm. The goal node is mapped to the node nearby the boundary in the eyeshot of the robot, and the best local path is planned, which the robot goes ahead for a step. The algorithm iterates until the robot arrives at the goal node. The path gained is safe and optimal. Simulation results illustrate that the algorithm can be used to plan the optimized path for mobile robot even in the complex and unknown static environment, and the robot can avoid the obstacles safely by the path with the new algorithm.
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Computer Engineering. 2007, 33(20): 210-212,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.073The dyadic wavelet transform utilizes local modulus maximum of a wavelet transform to obtain multiscale edges information. This paper analyzes the statistical characteristics of the wavelet detail coefficients of the dyadic wavelet transform, and brings forward the wavelet coefficients histogram of nature texture image which can be modeled by a family of exponentials. It studies the ways to extract the texture features using the first-order and second-order (co-occurrence) based on the dyadic wavelet transform. Experimental results show that methods of Manjunath and second-order of the dyadic wavelet are better than that of scalar wavelet on texture image retrieval.
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Computer Engineering. 2007, 33(20): 213-215,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.074The cross-platform 3D game development technology, especially the concerned optimization technology, is widely regarded. This paper takes a cross-platform 3D game for example, and analyzes various functions realization and optimization technologies, including texture technology, display list technology, advanced fond technology, anti-alias technology and the strategy on render sequence. It gains a better game effect by using these optimization technologies.
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Computer Engineering. 2007, 33(20): 216-218. https://doi.org/10.3969/j.issn.1000-3428.2007.20.075
This paper discusses the problem of rendering scenes including high dynamic range material objects. In the approach, a GPU-based per-pixel lighting algorithm extending the traditional material model is used in scene rendering as well as outputting a high dynamic range image. A physically-based glare effect simulation algorithm is used in the post-process state. And a tone-mapping algorithm is used to convert the high dynamic range image to low dynamic range and output the image to screen. -mapping algorithm
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Computer Engineering. 2007, 33(20): 219-221. https://doi.org/10.3969/j.issn.1000-3428.2007.20.076This paper presents a global vector quantization(VQ) algorithm based on adaptive classified vectors in discrete cosine transform (DCT) domain. In order to reduce the dimension of vector and the computing time while increasing the searching speed and compression ratio, the DCT-transformed vectors are classified as smooth vector, or edge vector or texture vector adaptively, and the length of the vectors is determined according to their types of class, and the corresponding code-book is designed by using the modified VQ algorithm. Moreover, to improve the motion compensation rate for vectors between the consecutive frames in the case of illumination variation, the DCT coefficient is removed from the transformed vector and coded individually. Experimental results show that the proposed algorithm can provide good video coding performance in terms of compression ratio and PSNR, especially applying to the scenarios where the illumination has a great variation, such as intelligent video monitoring system and underwater video imagery.
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Computer Engineering. 2007, 33(20): 222-224. https://doi.org/10.3969/j.issn.1000-3428.2007.20.077This paper proposes a novel isosurface extraction approach. This method is based on the algorithm of ray-isosurface intersection, simulating the 3D scanner to compute the isosurface. The proposed method employs the high parallel computing ability of the modern GPU to complete the main process, and the final result is represented as a set of points based on the method of iso-splatting. This approach achieves a high quality image and a high FPS rate by controlling the quantity of points and avoiding the invisible portions. To validate the approach against the traditional one, several datasets are tested in the experiment, and significant improvements are revealed in both FPS and quality.
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Computer Engineering. 2007, 33(20): 225-227. https://doi.org/10.3969/j.issn.1000-3428.2007.20.078The paper makes an analysis on the model of special effects in Vega software environment. Based on the analysis, this paper reaches a conclusion that it is difficult to simulate lightning in Vega. By describing the relation between Vega and OpenGL, it is viable to simulate lightning in Vega by using OpenGL. By introducing the technology of texture mapping into lightning rendering, this paper presents a high-speed rendering method, which comes true in Vega. Experimenal result shows that the method is of great use and extends the function of special effects in Vega.
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Computer Engineering. 2007, 33(20): 228-230,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.079A new method of mesh simplification with face cluster is presented, it carries out the octree to divide the space, puts triangled-meshes into different spaces, then clusters the triangled-meshes in the same space. After space division, extracts features of every region and triangulates them by constrained delaunay triangulation. At last, it improves the whole speed of simplification.
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Computer Engineering. 2007, 33(20): 231-232,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.080This paper presents the hardware design and implementation of high speed data transport in hardware platform. In the hardware platform there are three different high frequency parts to be considered in hardware design, as the performance of the whole hardware system is to how to deal with them. Surface coplanar waveguide(CPW) with ground and surface micro strip structures are applied to whole hardware design, the theory and design are discussed. The good performance of small batch product proves the correctness of impedance design.
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Computer Engineering. 2007, 33(20): 233-235. https://doi.org/10.3969/j.issn.1000-3428.2007.20.081A surveillance experiment system based on foreground segmentation technology is presented. Information of the moving object is gotten from the specific environment by foreground segmentation arithmetic, from which exception is confirmed. Once the exception happened, alarm will be given, the exceptional image is also sent to client in the way of cable network. The hardware and software structure of the system, pivotal technology and realization approach of the system are presented.
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Computer Engineering. 2007, 33(20): 236-238. https://doi.org/10.3969/j.issn.1000-3428.2007.20.082This paper analyzes problems faced by 3D platform for lunar rover path plan. It presents a way to construct a 3D platform for lunar rover path planning, which includes 3D model construction, obstacle abstraction, path plan and 3D display. The authors use it to validate virtual agent-based obstacle avoidance method for behavior control lunar rover. Simulation result shows this platform can be used to validate path planning algorithms and solves the 3D display problem and interface problem.
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Computer Engineering. 2007, 33(20): 239-241,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.083This paper discusses the methods about how to construct a cross debugger in bus-based multi-DSP system. Some drawbacks of hardware emulator are mentioned. The rationale of implementation of debugger for DSP is discussed. It presents a method called dynamic monitor to minimize the footprint of the debugger, shows the test result to prove that the bus-based cross debugger has better performance and multiprocessor support than hardware emulator.
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Computer Engineering. 2007, 33(20): 242-244. https://doi.org/10.3969/j.issn.1000-3428.2007.20.084This paper presents and implements an asynchronous network backup system based on MS-Windows. This system monitors the write operations of local application server on the level of logical volume and encapsulates the information in a replay record, which is sent to the local gateway. After it is cached in the local gateway, the records are transmitted to the remote backup server asynchronously. The same write operation is carried out in the corresponding volume in the remote backup server. This system can be applied to all kinds of file systems and storage devices in windows and it realizes the remote backup of logic volumes in the local application server.
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Computer Engineering. 2007, 33(20): 245-247. https://doi.org/10.3969/j.issn.1000-3428.2007.20.085In order to implement the interoperation of the fieldbus and supply the uniform access interfaces for the users as to shield the heterogeneity of the different fieldbus, the real-time fieldbus integrative network based on ACE and TAO is researched and implemented so that various kinds of fieldbus protocols can be converted to each other and transmitted in Ethernet. The network has the capability of real-time scheduling. Compared with the conventional devices, it is not limited to one-to-one conversion, and independent of the object location, programming language, OS platform and communication protocols.
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Computer Engineering. 2007, 33(20): 248-250. https://doi.org/10.3969/j.issn.1000-3428.2007.20.086This paper presents a full-custom design of a multi-port 32x32 bits register file with 6 read ports and 2 write ports, including architecture design, circuit design, layout design, simulation and verification, modeling and library compiling. As all read/write ports are independent, it can read 6 32-bit data and write 2 32-bit data simultaneously in one clock cycle. The design employs high-speed SCL address-decoder and word-line grouping method to reduce access delay. Its layout is realized in 0.18μm 6-layer-metal P-trap CMOS technology and passes final verification and post simulation.
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Computer Engineering. 2007, 33(20): 251-252,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.087Architecture of redundant broadcasting system is presented. SPN model is built and influence on system availability by real-time transmissions is analyzed. Some key modules such as check-in, check-out, time synchronizing, faults monitoring and diagnosing are discussed. Faults simulations prove the design’s effectiveness.
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Computer Engineering. 2007, 33(20): 253-255. https://doi.org/10.3969/j.issn.1000-3428.2007.20.088To achieve software engineering design under the guidance of software architecture, this paper proposes an approach of user interface design, which is based on architecture and model and can support automatic code generation. In the approach, the architecture of user interfaces is taken as the direct description of engineering model, and the construction process of the user interface presentation models have to be constrained by the architecture, and within the code generation phases, lots of design patterns of user interface concerning different components can be used. It indicates that software engineering design under the guidance of software architecture is feasible.
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Computer Engineering. 2007, 33(20): 256-258. https://doi.org/10.3969/j.issn.1000-3428.2007.20.089The fast development of embedded technology in consumer electronics requires a more applicable GUI supporting system. This paper gives a solution to a light-weight and efficient GUI supporting system for a resource limited system. With the specific requirement of DTV applications, the architecture, porting and realization of this embedded GUI supporting system is expounded. This GUI system has successfully run on the target platform, which proves the validity of the proposed solution.
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Computer Engineering. 2007, 33(20): 259-261. https://doi.org/10.3969/j.issn.1000-3428.2007.20.090This paper presents the design and implementation of a grid file access interface (GFAI). GFAI implements a POSIX and scalable grid file access interface, which can screen the details of access protocols for different storage systems and solve heterogeneity problem of different file access or file transfer protocols. It provides a uniform and easy use grid I/O interface for users.
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Computer Engineering. 2007, 33(20): 262-264,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.091Flood control decision support system for the Weihe river is realized based on the C/S systematic structure. An advanced technology of distributed component object model (DCOM) is adopted, and an aided decision support system and expert decision support system are designed by combining MapX GIS development platform with Delphi-database development tool. The flood control decision support system is realized on the background of Weihe valley. The test examples show that the system of this study is not only credible in design and complete in function but also has good practicability, and it can provide full information about rain, water and project operation to support flood control decision support.
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Computer Engineering. 2007, 33(20): 265-267. https://doi.org/10.3969/j.issn.1000-3428.2007.20.092A new method is proposed to develop a test system about a kind of automatic pilot of helicopter. Based on the interface to system target of RTW(real-time Windows target) toolbox, using VxWorks and SimuLink toolbox of Matlab, the model of helicopter can be embedded in PC/104. In this way, a real-time test system on automatic pilot of helicopter can be built easily. The final results validate the feasibility of this method.
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Computer Engineering. 2007, 33(20): 268-269,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.093This paper presents the certification authority(CA) system model, then sets up the CA system architecture based on the model, and implements the CA system under openCA framework, in accordance with specific requirements of IHEP grid environment. According to actual experiences of operations and maintenance of IHEP grid CA, it extends the utilities functions and enhances the system security.
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Computer Engineering. 2007, 33(20): 270-273. https://doi.org/10.3969/j.issn.1000-3428.2007.20.094Airborne distributed operation system is key to the new generation avionic system support platform i.e. the system affects the performance and cost of the new generation integration avionic system. This papers analyzes features and performances of airborne distributed operation system and proposes an idea of designing a three-layer-tack software. By using standard interface(physics and logic interface), separation is obtained between layer and layer, and module and module, which achieves function modularization, software hardware isolation, software reutilization, etc. so as to meet the increasing demand of avionic system task ability for the new generation avionic system support platform
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Computer Engineering. 2007, 33(20): 274-276. https://doi.org/10.3969/j.issn.1000-3428.2007.20.095The transmission and display of video is an essential part in the e-learning system. Because of the great capacity of video data and durative transmission, the efficiency of the processing on the transmission and display module directly decides the stability and usability of the system. This thesis proposes a double-deck structure in which command and data are transmitted separately, as well as an idea which could solve the problems of the user mode through kennel mode. This thesis presents the feasibility of applying the virtual camera in e-learning system based on H.323, and gives a realization method furthermore.
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Computer Engineering. 2007, 33(20): 277-278,. https://doi.org/10.3969/j.issn.1000-3428.2007.20.096The real time exchange GAP is a new technology of network isolation, which is attracting more and more attention in network security. Aiming at the multi levels and distributing characteristic of school network’s security, this paper presents a “region security” settle project base on GAP. It explains the key technology of this project, and presents a method to realize this project.
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Computer Engineering. 2007, 33(20): 279-282. https://doi.org/10.3969/j.issn.1000-3428.2007.20.097Chinese input method is an important part of human-computer interaction in Chinese software applications. Currently, the Chinese input method is not supported by the widely used embedded GUI systems. This paper introduces several most popular embedded GUI systems and details about the principle and the core algorithm of the Chinese input method, and introduces how to implement the Chinese input method in different embedded GUI systems.
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Computer Engineering. 2007, 33(20): 283-封三. https://doi.org/10.3969/j.issn.1000-3428.2007.20.098The aim of real-time collaborative design system (RCDS) is to make the communication between designers in different places more effective. This paper analyses the key technologies in RCDS, and suggests a new way to design a reliable and easy-developed system. On this basis a prototype system CollabVue is implemented. Integrated with PDM, it can implement data sharing and make RCDS more useful in the practical design.
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