20 September 2006, Volume 32 Issue 18
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Computer Engineering. 2006, 32(18): 1-2,5. https://doi.org/10.3969/j.issn.1000-3428.2006.18.001Combining the flexibility and ease of use of paper and pencil with the processing power of the computer, computer aided sketching design(CASD) technology specially suits for conceptual design and can help designer write down design ideas rapidly. For many years it has been one of the key issues on which many specialists and scholars have research. Based on application domains of sketching technology, the present situation of CASD is introduced. From four aspects of CASD, that is user interface design, low level sketch process, high level sketch interpretation, 3D sketching modeling, research method of some key technologies of CASD are analyzed. The development tendency of CASD is predicted.
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Computer Engineering. 2006, 32(18): 3-5. https://doi.org/10.3969/j.issn.1000-3428.2006.18.002Software engineering economics(SEE) is a new research direction for researchers, which is an integration of software engineering and economics, an enhancement or an extension of them. The notion and the relationship between SEE and software product value research as well as the economics research are discussed. Some recent research developments models and technologic classification are surveyed. And further research content, research trends framework and hierarchy structure are presented.
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Computer Engineering. 2006, 32(18): 6-8,31. https://doi.org/10.3969/j.issn.1000-3428.2006.18.003A time Petri net model based on resources is presented so as to model static schedule of distributed real-time embedded systems, and analyze system performances. The model attaches processor and communication resources, and respective priorities to transition, and well model following distributed embedded systems: using preemptive schedule based on fixed priority on single processor, using non-preemptive schedule for communication among processors. At last, the model’s semantic and property is analyzed, and state class graph is constructed.
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Computer Engineering. 2006, 32(18): 9-11,1. https://doi.org/10.3969/j.issn.1000-3428.2006.18.004This paper presents a model of cross-language information retrieval(CLIR) based on language concept space(LCS), the model takes formalized context framework which is formed in language concept space as mediated interface, the framework is three-coordinated and composed of domain, situation and background. The model can avoid the disadvantage of the word sense ambiguity which occurs in the traditional CLIR. The experiments indicate that the LCS based CLIR system has good performance.
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Computer Engineering. 2006, 32(18): 12-13,2. https://doi.org/10.3969/j.issn.1000-3428.2006.18.005Multicast source authentication is one of the main challenges of securing multicast communication. The non-repudiation multicast source authentication scheme proposed by Li and Huai is claimed to be very efficient and robust to packet loss. However, with selectively intercepting and discarding of some packets, the paper shows that this scheme is vulnerable to forgery attacks. Based on Chernoff bound, the attack can be defeated by careful selection of security parameters of the scheme.
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Computer Engineering. 2006, 32(18): 14-16,6. https://doi.org/10.3969/j.issn.1000-3428.2006.18.006The circuit and topology of RS232C interface are analyzed to reveal the mechanism of multiple callings from terminals. Poisson distribution is introduced to describe the calling process and develop the collision model. A collision probability depends on calling frame format, baud rate and calling frequency. The collision probability of calling from two or more terminals is less than 0.01% when mean calling frequency is less than 10 times per second. The collision can be listened, identified and compensated with another calling, whose collision probability is less than 0.000 1% . It is showed that the communication strategy of multiple terminals calling to central computer with RS232C protocol is feasible.
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Computer Engineering. 2006, 32(18): 17-19. https://doi.org/10.3969/j.issn.1000-3428.2006.18.007The maintenance cost of base level for torpedo weapon system is the highest in the three levels maintenance costs. The maintenance time of base level should be forecasted to use money in reason. Based on the thought of fuzzy theory, the AGM(1,1,ω) model is brought forward, which is developed form of grey GM(1,1) model. At the same time, AHP method is used in confirming the best weight value of the AGM(1,1,ω) model. As an example, a model of base level maintenance time model for torpedo weapon system is set up. Result indicates that this method can achieve satisfactory precision, and has practical value.
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Computer Engineering. 2006, 32(18): 20-22. https://doi.org/10.3969/j.issn.1000-3428.2006.18.008At present, the identification of check types need some marks on the checks such as frame lines or classified code. However, the classified marks are not shown in all the actual checks. An identification approach of twice classification based on regulated morphological operations which is transformed hierarchically with regulated hit-or-miss transformation by the structural feature of the image, is proposed without any restriction to the check style. Analysis and experiments show that the approach is with low computational complexity, high speed and high correct rate.
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Computer Engineering. 2006, 32(18): 23-24,3. https://doi.org/10.3969/j.issn.1000-3428.2006.18.009The algorithm and the search strategies of particle swarm optimization are introduced, on base of which concepts such as equivalent transformation, the difference value transformation and the transform serial sequence are defined according to characteristics of 0-1 knapsack problem, then a kind of special particle swarm optimization that is applicable to solve 0-1 knapsack problem is designed. The experimental results show the possibility and the efficiency of the modified particle swarm optimization on solving 0-1 knapsack problem.
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Computer Engineering. 2006, 32(18): 25-27. https://doi.org/10.3969/j.issn.1000-3428.2006.18.010Customer fraud restrains the consumptions of customers to a certain extent, which might impede good-fellowship between telecom service providers and customers. By that means, this behavior impairs telecom service providers’ market competition. The paper examines customer fraud is a very sophisticate phenomenon which is diverse and nonlinear. From the point of view of statistics, it is difficult to build up prediction model. Aiming at these problems, the paper puts forward a neural network based on recursive prediction error (RPE) algorithm to build up such a model, and adopts modified dynamic oblivious coefficient to ensure stable convergence. Finally the test results show that the proposed neural networks model based on modified RPE algorithm outperforms BP neural networks model. This proves the implementation of the proposed prediction model to be practicable and effective in its application.
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Computer Engineering. 2006, 32(18): 28-31. https://doi.org/10.3969/j.issn.1000-3428.2006.18.011To addressing the self adaptation problem arises from sensornet, this paper argues that integrating context aware with sensornet is feasible. To build such a context aware sensornet, proper context description and storing mechanisms must be provided. It proposes RBLS, a role based local storage scheme. Aimed at providing context storage support for sensornet, RBLS stores contexts at node’s local space and dynamically allocates extra spaces according to the roles a node holding. A “snapshot” is used by RBLS to record a neighbor’s private contexts. Simulation results reveal that RBLS is simple and energy efficient.
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Computer Engineering. 2006, 32(18): 32-34. https://doi.org/10.3969/j.issn.1000-3428.2006.18.012This paper proposes a novel snake model based on fractal dimension feature to segment man-made object in nature background. It first uses the fractal dimension feature to define an adaptive weighting function and then introduces it into the snake energy in order to suppress the nature clutter. Snake driven by the proposed model can evolve from the initial position to the man-made object without disturbances of nature clutters, even if the initial curve is far away from the solution. Experimental results validate the effectiveness and feasibility of the model.
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Computer Engineering. 2006, 32(18): 35-38. https://doi.org/10.3969/j.issn.1000-3428.2006.18.013With wide deployment of IPv6 protocol, traditional IPv4 route lookup algorithms are no longer suitable for packet forwarding of IPv6 routers. Based on the algorithm of binary search on hash tables, this paper describes a new algorithm, ABSH, for best matching prefix of IPv6 address. The algorithm manifests high performance when it is applied to super huge route table. Also, in order to decrease memory use, the paper presents several improving schemes. These schemes are analyzed by experiment data.
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Computer Engineering. 2006, 32(18): 39-41. https://doi.org/10.3969/j.issn.1000-3428.2006.18.014In order to satisfy the demands of multi-clients’ concurrent database access to acquire location-based information, the key technology of database connection pool is analyzed on the basis of the architecture of LBS. The design and implementation of database connection pool are done through an instance of vehicle positioning platform, which proves the efficiency of this method.
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Computer Engineering. 2006, 32(18): 42-44,4. https://doi.org/10.3969/j.issn.1000-3428.2006.18.015It is fundamental to make standard of data element in the integration of information systems. Understanding data demand of information systems precisely and constructing the global data view are the precondition of instructing data standardization. Based on the data re-instruction of information system, the paper compares the characteristics of methods of data element distilment. It is convenient for consumers to start from appliance project to choose appropriate method of data object distilment, and improve quality and efficiency of data standardization.
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Computer Engineering. 2006, 32(18): 45-47. https://doi.org/10.3969/j.issn.1000-3428.2006.18.016In NP-based device, there are various kinds of packets between data plane and control plane. If critical packets are not processed in time, the system may enter some unstable states. Thus, the packets should be processed according to their importance. From the perspective of control plane OS design, the user must schedule packet-processing processes based on packet attributes. This paper proposes a packet attributes-based scheduling policy to alleviate the problem. Experimental results show that this scheduling policy can achieve the design goal.
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Computer Engineering. 2006, 32(18): 48-49,9. https://doi.org/10.3969/j.issn.1000-3428.2006.18.017An approach to role implementation based on Mediator pattern is introduced, and a prototypical implementation (called Rava) of the approach is also presented. The paper discusses the similarities and differences between role and Aspect concept in AOP, and implementation method of dynamic AOP with Rava. Consequently, the two concepts of role and Aspect are unified in implementation level.
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Computer Engineering. 2006, 32(18): 50-51,5. https://doi.org/10.3969/j.issn.1000-3428.2006.18.018The management of business register system is an important component of national economic census. Based on the associate rules, this paper investigates the information access correlation and constructs the recommending agent of business register system. Furthermore, Boolean matrix and incremental mode are employed to enhance the disposal efficiency of register frequency set. At the same time, data objective mode used in the paper not only accomplishes remote transmission of business register database but also upgrades flexibility of recommending agent as well.
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Computer Engineering. 2006, 32(18): 52-54,6. https://doi.org/10.3969/j.issn.1000-3428.2006.18.019To achieve the function of workflow management, the business process must be abstracted from the real world and described by a kind of formal method. The result is workflow model. This paper discusses workflow models and their formal descriptions using parallel finite automata(PFA)theory. Based on the analysis of workflow and PFA, it proposes the method of mapping workflow management concepts onto PFA, and this method can map four types of routing constructs advocated by WfMC onto the structure of PFA. An executing process description of PFA is given, that is, a framework of workflow engineer is given. Because PFA is a graphics and mathematics computing model, after PFA has been built up, it has grounded for the analysis of workflow static and dynamic characteristic, thus makes the preparation for the further research.
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Computer Engineering. 2006, 32(18): 55-57. https://doi.org/10.3969/j.issn.1000-3428.2006.18.020The Web usage mining is very important content of Web mining. It is applied in many activities. The application of Web usage mining in E-commerce Web’s merchandising will find many important information. To effectually use this information, it will prompt the development of the E-commerce Web.
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Computer Engineering. 2006, 32(18): 58-60. https://doi.org/10.3969/j.issn.1000-3428.2006.18.021Task schedule is very important in the OpenMP specification. Selecting different scheduling strategies plays a key role on the performance of a parallel program by affecting the load balance and schedule overhead. The OpenMP API specifies four scheduling strategies: static, dynamic, guided and runtime. A quantitative analysis on the load balance and schedule overhead of different schedule strategies is studied under the condition of assuming that executing each iteration spends the same time. Some principles for choosing schedule strategies are also discussed.
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Computer Engineering. 2006, 32(18): 61-63. https://doi.org/10.3969/j.issn.1000-3428.2006.18.022This paper describes the principle and realization of reviewing SOFL specification. With the checklist for SOFL, it deals with two aspects relatively independent and related——process-oriented review and data-oriented review, helping reviewer find defects, internal inconsistency, incompleteness, dissatisfaction of SOFL specification. At the same time, it keeps all the recorded comments or descriptions in a well-organized archives so as to analyze.
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Computer Engineering. 2006, 32(18): 64-66. https://doi.org/10.3969/j.issn.1000-3428.2006.18.023As a standard of describing the scheme information or structure information of XML document, XML Schema plays an important role in the building of XML index and improvement of the query efficiency. Now most of the XML index structures focus on study the structural query，but few indexing structures can solve the updating problem of XML document and give quick response to those invalid queries. Based on the numbering schemes of XML document that have already proposed, this paper proposes a Schema-based XML indexing structure that can not only support the dynamic updating based on the verifying of validity in order to keep the consistency between the XML document and XML Schema, but also give the response to the user’s invalid path query in a short time.
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Computer Engineering. 2006, 32(18): 67-69. https://doi.org/10.3969/j.issn.1000-3428.2006.18.024Colored Petri net(CPN) is a kind of high level net system, which is a powerful tool for modeling the systems. The foundation and some features of CPN are described. After examining the current grid-scheduling circumstance, this paper puts forward a novel grid-scheduling model based on CPN, and analyses two typical grid-schedule algorithms with the state space method.
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Computer Engineering. 2006, 32(18): 70-71,7. https://doi.org/10.3969/j.issn.1000-3428.2006.18.025In the process of clustering the visitors’ travel path patterns, this paper achieves a more reasonable and accurate model from combining the content as well as the path a user visits, at the same time improves the former research in measuring the similarity of travel path pattern and presents an effective way to perform it. The result shows that the improved method decreases the number of the clustering result, and is much better in finding the potential user classes, which achieves the expectation of this paper.
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Computer Engineering. 2006, 32(18): 72-74,8. https://doi.org/10.3969/j.issn.1000-3428.2006.18.026Blue whale distributed file system(BWFS) overcomes the shortcomings of traditional storage system in performance, capability, shareability, scalability, manageability and so no. It enhances the availability by adopting the soft-technology of connection-copy, channel-switch, and request-rebuild for network fault-tolerant without extra hardware support. Aiming at the system availability, the article analyses the fault about network faced by BWFS, expatiates the technology of network fault-tolerant adopted by BWFS from the view of system software, tests and compares its efficiency .
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Computer Engineering. 2006, 32(18): 75-78. https://doi.org/10.3969/j.issn.1000-3428.2006.18.027It comes the era of component-based software when the technology of components and its specification comes to the horizon. However, the endowments inherent in component-base software are challenging the traditional software testing method: because of the independence of component development, how to ensure the quality of a software system integrating various components without accessing their source code? With the theory of observation construction, this paper constructs a new software testing method, which is based on the theory of automaton and could verify the dynamic behavior of component-base software. Finally an example is given to prove the method valid.
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Computer Engineering. 2006, 32(18): 79-80,8. https://doi.org/10.3969/j.issn.1000-3428.2006.18.028To improve query processing, various numbering schemes for XML documents are proposed. However, the most of them have poor updating performance now. A new dynamic numbering scheme (DNS) is proposed based on analyzing some popular numbering schemes. DNS uses real numbers instead of integers to denote the region. Therefore it can utilize the gap between consecutive nodes to code the new node or subtree. Moreover, DNS can adjust the codes of some nodes in some parts of the whole tree according to the condition of updates.
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Computer Engineering. 2006, 32(18): 81-83. https://doi.org/10.3969/j.issn.1000-3428.2006.18.029This paper introduces an application software distribution system based on RMI communications. This system ameliorates the traditional installation model of software distribution and adopts a distributed management model. The manager can utilize any computer in the LAN to realize such functions as software distribution, remote installation, remote deletion and remote management.
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Computer Engineering. 2006, 32(18): 84-86. https://doi.org/10.3969/j.issn.1000-3428.2006.18.030This paper presents the implementation method of embedded TCP/IP for multi-thread and real-time application, together with the supporting example for explanation purpose. Aiming at the application of medical microscope digital images diagnoses, it implements embedded TCP/IP stacks based on the software-hardware platform of µC/ OS-II and ARM7 Core in middleware development method. By collocating rationally the architecture of embedded HTTP Server, establishing the reuse mechanism of system resource, it supports the multi-thread and real-time Internet application. The experiment shows that the embedded Web server performs well. The development modes based on software-hardware platform increases the stability of system and shortens development time. It is a feasible development method.
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Computer Engineering. 2006, 32(18): 87-89. https://doi.org/10.3969/j.issn.1000-3428.2006.18.031There have both deficiency for structure index and inverted lists during query XML documents. The paper presents a strategy that combines structure index and inverted lists and a querying algorithm based on joint path expression, which can effectively reduce the cost of practical execution and improve querying speed.
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Computer Engineering. 2006, 32(18): 90-91,1. https://doi.org/10.3969/j.issn.1000-3428.2006.18.032Based on TCP Vegas congestion control algorithm, this paper presents Vegas-AB algorithmr. This algorithm can be fit for Iridium-similar LEO satellite networks. The improvement idea of Vegas-AB algorithm comes from Vegas and Vegas-A algorithms; it is the harmonization of two algorithms. The name of Vegas-AB means that this algorithm can change its parameters Alpha and Beta, and the main outline of Vegas-AB algorithm is still in accordance with Vegas-A algorithm. During congestion avoidance, the target of Vegas-AB algorithm, Vegas-AB algorithm is more radical and aggressive. Simulation results show that Vegas-AB algorithm is superior to Vegas and Vegas-A algorithms in throughput and round trip time.
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Computer Engineering. 2006, 32(18): 92-94. https://doi.org/10.3969/j.issn.1000-3428.2006.18.033In order to increase the efficiency of embedded system development, this paper presents a method of designing HTTP engine in embedded Web server . In terms of the process of reply to HTTP request, it abstracts nine discrete states. These state is regarded as the states of FSM. These states is used to show the states during completing HTTP connection. Furthermore the state transition can be shown in the state table. By replying to the client connection using FSM, the tasks in the server becomes more effective. The final experiment shows that once the HTTP engine is realized in the described method, the reply time to service is reduced evidently.
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Computer Engineering. 2006, 32(18): 95-97. https://doi.org/10.3969/j.issn.1000-3428.2006.18.034This paper firstly studies the RWA algorithm in WDM optical network, then proposes a novel self-adaptive RWA algorithm considering lightpath PRI and network fairness and gives the detailed approaches. The algorithm can make full use of network resources and keep the load distribution in balance, and also give attention to the rationality of network resource assignment.
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Computer Engineering. 2006, 32(18): 98-99,1. https://doi.org/10.3969/j.issn.1000-3428.2006.18.035The BTP uses a two-phase outcome coordination protocol with a complete set of timeout parameters (shortly 2PCt) to ensure the overall application achieves a consistent result. With respect to the above situations this paper has posed a category of non-blocking extended two-phase commit (2PC) protocol Tx2PCt (stand for Termination properties-oriented eXtended 2PC with Timeouts) to evolve BTP’s 2PCt. It mainly gives some implementation and test examples of Tx2PCt model, which are developed in a major Web services commercial developing platform—Microsoft ASP.NET. The testing results show the rationality of the Tx2PCt model’s premises, and justify that the Tx2PCt’s behavior is according with the expectation in the aspect of success transaction throughput.
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Computer Engineering. 2006, 32(18): 100-102,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.036This paper studies an end to end QoS architecture between wireless and wire based on DiffServ and IEEE802.11e, introduces the characters of 802.11e, 802.1D/Q and DiffServ, analyzes priorities mapping each other and presents the hierarchical QoS parameters interface between DiffServ and 802.11e in terms of traffic classifying, markering and shaping.
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Computer Engineering. 2006, 32(18): 103-105. https://doi.org/10.3969/j.issn.1000-3428.2006.18.037In WDM networks, routing and wavelength assignment (RWA) is tightly integrated, i.e. in establishing an optical connection, it must deal with both selecting a suitable path and allocating an available wavelength for the connection. This paper proposes a genetic algorithm for the problem of minimizing the number of wavelength required in a network for a given set of delay-constraint multicast requests, which can efficiently exploits the combination of alternative delay-constraint paths for the given multicast requests through a suitable two-dimensional chromosome representation and crossover and mutation operators. Simulation result shows that the proposed algorithm can produce suboptimal delay-constraint routing trees that substantially save the number of wavelength used quickly.
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Computer Engineering. 2006, 32(18): 106-108,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.038This paper introduces simply kinds of the current spam filtering technology and analyzes the disadvantages of some algorithms which have been implemented on spam filtering field. A new algorithm(SECTILE) is chosen to implement content based filtering. Three kinds of filtering technology (black/white list based, rule based, content based) are implemented on the spam filtering system it designs. Experiment and analysis prove that the efficiency and accuracy of spam filtering are improved.
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Computer Engineering. 2006, 32(18): 109-110,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.039With the development of large scale switching network, the study is transferred from network layer to data link layer. The link layer topology discovery can discover the physical topology internal a LAN, which the network layer topology discovery can not discover. A link layer topology discovery algorithm based on spanning tree algorithm is proposed. The algorithm gets the STP information from the bridge MIBs with the tool of SNMP. It can calculate the link layer topology on the basis of the information. The algorithm is simple and with high performance in application.
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Computer Engineering. 2006, 32(18): 111-113. https://doi.org/10.3969/j.issn.1000-3428.2006.18.040Grid emerges as a new infrastructure for Internet-based parallel and distributed computing. This paper proposes the data movement service based on load balance in grid. The demand and the matter of data movement in grid are analyzed. The general design and the particular project are introduced concretely.
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Computer Engineering. 2006, 32(18): 114-116. https://doi.org/10.3969/j.issn.1000-3428.2006.18.041This paper analyzes the circumstance of data dissemination in P2P network, aiming at the maximum throughput of the whole network and proposes a model of data dissemination. Then on this model, it develops a practical algorithm performed in polynomial time to approximately compute the optimal usage of network bandwidth and the corresponding routing strategy, and the simulation result turns out to be obviously fine.
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Computer Engineering. 2006, 32(18): 117-119. https://doi.org/10.3969/j.issn.1000-3428.2006.18.042This paper introduces two popular Ad Hoc route protocols, including DSR and AODV. It sets up several scenarios to collect the statistics of end-to-end delay, throughput, energy cost and tests the impact on network performance while the node density, the movement state, data transmit rates, packet length are different for both AODV and DSR routing protocols. All the simulation results are collected under the Win2000 and OPNET environments, and this work is helpful to practical engineer applications.
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Computer Engineering. 2006, 32(18): 120-121,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.043The algorithm resilient geometric distortion is an important research direction in copyright protection. This paper proposes an image watermark algorithm based on discrete Fourier transform (DFT) and singular value decomposition (SVD) because of the good property of DFT amplitude matrix and the characteristic of SVD that it is stabilization to geometric distortion such as rotation, scale and translation. Experimental results show that the algorithm has more embedding capacity and robust to common attacks and geometric distortion.
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Computer Engineering. 2006, 32(18): 122-124. https://doi.org/10.3969/j.issn.1000-3428.2006.18.044In order to decrease the long training time for most good generalizable intrusion detection system, a new intrusion detection method using ratio of kernel central distance (RKCD) which needs no training time and has good generalization ability is presented. The nonlinear separable intrusion data is classified using kernel method. Then the framework of the system using RKCD is introduced. The simulation results on system call traces show that this method performs well, saves the training time at the mean time.
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Computer Engineering. 2006, 32(18): 125-126,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.045A new efficient ID-based authenticated encryption scheme is proposed, in which some characteristics of bilinear map are used. As the authentication and recovery are separated in this scheme, anyone can identify the source of the ciphertext, but only the receiver can recover the plaintext. What’s more, the proposed scheme is also very efficient regarding to the computation costs and the communication overheads.
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Computer Engineering. 2006, 32(18): 127-129. https://doi.org/10.3969/j.issn.1000-3428.2006.18.046This paper provides a means to assist the PKI user to build the certification path by using an agent. It also proposes PKI trust model based on agent and agent structure, as well as the updating algorithm of certification path. It has been proved by analysis that under the circumstances of only one hop between each node in communication network and with 5 nodes in hybrid trust model, this method could improve the efficiency to 2.6 times than that of the traditional method.
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Computer Engineering. 2006, 32(18): 130-132. https://doi.org/10.3969/j.issn.1000-3428.2006.18.047One of the most important fields in network security is the defense against DDoS attacks, in which many methods are introduced in literature, namely DWARD, IP trace, packet classification, anomaly traffic detection. Every current method has its advantages and disadvantages. With the idea of classification defense, this paper presents an integrated scheme which has synthesized two complete defending systems against DDoS attacks. The integrated system has more powerful functions in fighting against DDoS attacks. The good performances of the new system for fighting against DDoS attacks are listed as fellow: low false alarm probability, high speed of response, slight affection to the normal traffic.
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Computer Engineering. 2006, 32(18): 133-134,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.048This paper elaborates a way of thinking about covert channel analysis in Oracle from the concept of covert channel, discusses contents and levels of covert channel analysis, the mark method of covert channel, the calculation and measurement of covert channel band width and the processing of covert channel, which provides a new way of improving Oracle 9i’s security performance.
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Computer Engineering. 2006, 32(18): 135-137,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.049This paper establishes the hierarchy model of the factors that influence information system recovery abilities, and confirms the weight of influence factors in each level of the model with AHP method. Based on this, it establishes fuzzy synthetic evaluation model. It also evaluates the information system disaster recovery ability of a bank in Shanghai with these methods.
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Computer Engineering. 2006, 32(18): 138-140. https://doi.org/10.3969/j.issn.1000-3428.2006.18.050Transductive support vector machines (TSVM) classifies the new data vector based on the information only related to this data vector. This paper proposes an anomaly network traffic detection method based on TSVM. The KDD-99 intrusion detection competition data set is used to illustrate the performances of the TSVM. The performance-comparisons of TSVM and traditional inductive SVM are presented. The results show that TSVM can be used in intrusion detection practically.
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Computer Engineering. 2006, 32(18): 141-143. https://doi.org/10.3969/j.issn.1000-3428.2006.18.051With Internet goes further, people pay more and more attention to computer security problems. And among them, the number of buffer overflow attacks is growing by year. This article begins with the theory of buffer overflow attacks, describes a method and a tool using static analysis and dynamic analysis to detect buffer overflow in binary files, compares and analyses the result of running this tool and traditional buffer overflow detect tool and indicates the defects of the tool and how to improve it.
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Computer Engineering. 2006, 32(18): 144-146,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.052Fast correlation attack is one of the important cryptanalysis method for stream ciphers. This paper presents a new fast correlation attack algorithm which based on error-correcting codes. It divides the key into two parts using special parity check equations, and transfers the linear block code to a convolutional code with low rate and obtains the key from Viterbi decoding algorithm. The new algorithm notably reduces the decoding complexity of the fast correlation attack algorithm.
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Computer Engineering. 2006, 32(18): 147-148,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.053This paper discusses the common model to analyze and detect computer operation system vulnerabilities. Based on the model, it proposes a new model and arithmetic, BOVADA, to analyze and detect the buffer overflow vulnerability. Utilizing the special test code, BOVADA can determine the overflow function, overflow point, jump address of the system to be tested. Compared with other model and arithmetic, BOVADA has some advantages, such as more plain structure, more integrate function, and more accurate parameter. Finally, BOVADA is proved to be true on WorkStation service vulnerability of Windows2000.
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Computer Engineering. 2006, 32(18): 149-151. https://doi.org/10.3969/j.issn.1000-3428.2006.18.054This paper presents an algebraic method that the component of the field element can be expressed by a simple polynomial with the element itself as the variable over . The algebraic expressions of S-box and InvS-box can be resolved and the reasons why S-box has only 9 items but InvS-box has 255 items are explained with this method. In addition it proposes a quick power algorithm for polynomial over finite field. The experimental results indicate that the algorithm is better than direct multiplication.
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Computer Engineering. 2006, 32(18): 152-154. https://doi.org/10.3969/j.issn.1000-3428.2006.18.055A mandatory access control technique is proposed which is based on P2DR and cannot be bypassed. The framework of Unix host security monitoring system is constructed on multi-level security policy model through strong authentication, encapsulated Unix command and mandatory access control based on P2DR. And the system is mainly applied to Unix host security protection in secret network environment.
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Computer Engineering. 2006, 32(18): 155-156,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.056This paper systematically analyzes the rule matching algorithm of Snort, an open source-code NIDS. In order to increase effectively the rule matching speed, an approach of parameter-list-driven is proposed for the conditional checking subroutine during rule matching. The means can avoid repeatedly invoking the checking subroutines, can utilize relationship between parameters, and can significantly reduce invalid rules in the running time. Finally, two experiments are done for evaluating the efficiency of it. The result shows the approach can greatly improve the detecting performance of Snort.
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Computer Engineering. 2006, 32(18): 157-159. https://doi.org/10.3969/j.issn.1000-3428.2006.18.057This paper proposes a distributed authentication system with intrusion-tolerant feature. The authentication system is able to tolerate intrusions using the redundant proxy servers and shared authentication servers. With the method of distributing user’s key into several shared authentication servers, system continuously provides authentication services and not exposes user’s key even under intrusion. Through this scheme, the availability and security of authentication system are enhanced.
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Computer Engineering. 2006, 32(18): 160-162. https://doi.org/10.3969/j.issn.1000-3428.2006.18.058This paper discusses the general framework of existent streaming media digital rights management (DRM) and its deficiency, presents a new model for streaming media DRM by adapting to the property of streaming media. The new model is based on triple level encryption. The new model’s framework, process flow and encryption mechanism are described. The new model’s characteristic is analyzed and the new model is proved to be secure, real-time and upgradeable.
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Computer Engineering. 2006, 32(18): 163-165,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.059Most security technologies are designed to prevent unauthorized activity to resources, and security tools are put into place as a defensive measure. Therefore there is some shortcoming in protecting network. After analyzing the research situation and the shortcoming of security tools in intrusion detection and in protecting system, distributed virtual honeynet system is studied and implemented. The system is composed of hybrid virtual honeynet and low-interaction honeypot, which reduces the inherent risk of honeypot, adds the simulation’s trueness, and it makes up the shortcoming of exiting different type honeypots. As a dynamic security defensive mechanism, it can improve effectively integrate safety of large scale of network, and is completely supplement of traditional security mechanism.
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Computer Engineering. 2006, 32(18): 166-168. https://doi.org/10.3969/j.issn.1000-3428.2006.18.060Inter-domain route system is the critical part of the global communications infrastructure. However, inter-domain route system has severe healthy problems because of its own vulnerability. In view of inter-domain routing monitoring, it designs and implements a real-time security monitoring system based on anomaly behavior and traffic pattern. The system has real-time ability to detect anomaly of traffic and illegal route. As the same time, a BGP route table is maintained to prepare for further analysis based on UPDATE packet. In the end, some experiments have been done to evaluate system capability.
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Computer Engineering. 2006, 32(18): 169-171. https://doi.org/10.3969/j.issn.1000-3428.2006.18.061The technology of audit tracing is a very important aspect in network security. It is the process of memorizing and analyzing a series of computer security events produced by operating system, system application or user activity. This thesis introduces the basic conception , and the key technology and standard have been summarized. The detailed method and basic process of security audit have been proposed. This method has been proved to be effective and prone to be carried out.
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Computer Engineering. 2006, 32(18): 172-174. https://doi.org/10.3969/j.issn.1000-3428.2006.18.062A distributed intrusion detection system based on autonomous agent is presented. The architecture of the system is layer-based, with monitor, transceiver, and agent as the three functional entities. The system employs publish/subscribe communication paradigm to reduce the overhead and improve the efficiency of the communication.
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Computer Engineering. 2006, 32(18): 175-177. https://doi.org/10.3969/j.issn.1000-3428.2006.18.063Chameleon signatures are non-interactive signatures based on a hash-and-sign paradigm, whose building block is chameleon hash function, a trapdoor one-way hash function. The distinguishing characteristic of chameleon signatures is non-transferable. This paper proposes a new ID-based chameleon signature scheme from bilinear pairings, which is both secure and efficient.
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Computer Engineering. 2006, 32(18): 178-180,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.064The common security programming interface (CSPI) is the interface between security middleware and user. User can achieve the aim of security service by common security programming interface. This paper bring forward the architecture of security middleware at first. Then, the design and implementation of common security programming interface are presented.
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Computer Engineering. 2006, 32(18): 181-183. https://doi.org/10.3969/j.issn.1000-3428.2006.18.065Design of hardware encryption of military Godson computer is proposed. This novel method based on SRAM-based FPGA can be easily implemented without specific FPGA products. It can greatly enhance the system security and be convenient for the designer to choose FPGA products without constraints. Different encryption algorithms that can be used in this method are discussed for engineering selection purpose. And this method is finally applied in the design of military PC104 board based on Godson II.
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Computer Engineering. 2006, 32(18): 184-185,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.066This paper proposes simple SVM based on virtual vector transformation and local relationship feature according to example invariance features, and compares with tangent distance kernel, virtual SVM, human recognition etc by recognizing handwritten numbers in USPS. The method can acquire good raw error rate and its computation time is least. The results indicate that the method could sufficiently abstract invariance features in example data, and could be an effective measurement for pattern classification.
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Computer Engineering. 2006, 32(18): 186-188,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.067Product design is a circularly ascending process of knowledge accumulation and reuse. It is very difficult to manage and reuse knowledge. According to the classification of the design knowledge, a knowledge representation model is presented, which is integrated with design objects. Knowledge units are built to encapsulate the design knowledge, combing with various methods to describe knowledge. A conceptual model of design knowledge reuse is presented.
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Computer Engineering. 2006, 32(18): 189-191. https://doi.org/10.3969/j.issn.1000-3428.2006.18.068The activities of online auction produces a large number of transaction data. If utilized properly, these data can be of great benefit to sellers, buyers and site administrator. Typically, prediction result may help sellers optimize the selling price of their items. Thus, transaction time can be shorted and cost can be saved. This paper collects a lot of historical exchange data from Eachnet, an online auction website most famous in China, and uses machine learning algorithms to forecast the final price of auction items. On the basis of the categorization and preprocessing of data, the prediction is made. The prediction results and performances are discussed to verify the proposed solutions.
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Computer Engineering. 2006, 32(18): 192-194. https://doi.org/10.3969/j.issn.1000-3428.2006.18.069Based the study of stock market and the learn process of stockholders, the author designs a multiagent-based simulate model of stock market, illuminates the structure of this model. For the simulation of the learn process of stockholder and reflection of the intelligence of stockholder, the author designs two agent learn strategies, analyzes the invest effect under the experience based learn strategy, and compares the invest effect using learn strategy without using learn strategy, points out the study direction and target.
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Computer Engineering. 2006, 32(18): 195-196,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.070In order to get an ideal lane marks’ edge in a road image, an enhance edge method based on LOG operator is used to acquire a grads image, then the grads image is divided up by SUSAN operator, the lane mark edges is picked-up. In the divided up image, it is realized to identify lane marks because lane mark line parameters can be acquired by Hough transform, the lane mark real-time track is performed by establishing trapezoid areas. Experimental results show that the proposed method is characterized by reliability, good robustness and real-timeness.
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Computer Engineering. 2006, 32(18): 197-199. https://doi.org/10.3969/j.issn.1000-3428.2006.18.071In military railway transportation, the pallet loading problem is described as loading a set of equipments of different sorts into pallets of some given style. The models and algorithms for pallet loading problem are presented to satisfy different demands. First Fit algorithm and conditional mutation operator are introduced into simple genetic algorithm for obtaining a better solution, and an improved genetic algorithm is proposed for solving a kind of pallet loading problem. In the improved genetic algorithm, the idea of First Fit algorithm and conditional mutation operator is used to improve the ineffective chromosome in the process of evaluation, and the improved selection operator, crossover operator and mutation operator are used to solve the problem of premature convergence of genetic algorithm. The effectiveness of the improved genetic algorithm is convinced through computational results of an example. From the viewpoint of computational results obtained, it is confirmed that the improved genetic algorithm outperforms next fit algorithm, First Fit algorithm, First Fit decreasing algorithm and simple genetic algorithm.
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Computer Engineering. 2006, 32(18): 200-201,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.072The paper introduces a new feature compensation method which will induct the relativity of the prediction of spectrum based probability model in detail. The method evaluates the parameters of the joint distribution using the expectation maximization (EM) algorithm. The minimum mean squared error (MMSE) estimator for the speech feature parameters in spectrum-domain based the prior probability distribution is to enhance the correctness of speech recognition. The algorithm is tested in different noise and signal noise ratio (SNR). Subjective measure testifies that this method can increase the correctness of continuous speech recognition.
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Computer Engineering. 2006, 32(18): 202-205. https://doi.org/10.3969/j.issn.1000-3428.2006.18.073With the explosion of data on networks, it has been one of the important issues in Web search application that how to get Web resources to the user’s mind efficiently. We describe a new way of generating dynamic user profiles for personalization in Web resource search in this paper. It uses content-based Web search results classification to create a user profile, which is described by a RDF file. Such user characterizations are then used to find user groups based on cluster for those RDF files. Then dynamic profile and the traits of the corresponding user group in Web resources search can be used to provide a better service for the user.
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Computer Engineering. 2006, 32(18): 206-207,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.074Urban function partitioning is one of the important tasks of urban land utilization and management. The goal of urban function partitioning is to make the urban land form a set of specific function units and regular spatial structures. Spatial clustering is the key process of urban function partitioning. Based on the principle of self-organizing neural network, this paper presents a combined-type of spatial clustering. That is to say, the attribute features and their spatial positions are processed by a unitive spatial clustering model. This method fully mines the connotative spatial clustering information in spatial attribute data and spatial positions. The experiment shows that the unitive spatial clustering method can provide a sufficient and reliable basis for urban function partitioning.
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Computer Engineering. 2006, 32(18): 208-210. https://doi.org/10.3969/j.issn.1000-3428.2006.18.075In the past few years, content-based image retrieval has been becoming an active research area. There exists a gap between high-level concepts and low-level features. Relevance feedback is a promising approach to finding a mapping between semantic objects and low-level features. Feature weighting is also an important issue of multiple features combination in content-based image retrieval. This paper proposes a feature-weighting scheme based on rough set in relevance feedback. During the feedback process, a decision table is constructed. Then the weight of a feature space is determined by the precision of the decision rules. The experiments show that this approach is effective in feature weighting for content-based image retrieval, which gets higher efficiency than Rui’s algorithm.
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Computer Engineering. 2006, 32(18): 211-213. https://doi.org/10.3969/j.issn.1000-3428.2006.18.076The main point of automatic service discovery is locating services automatically. This paper introduces a solution to solve this problem. It uses owl-s profiles to publish service advertisement which describe service properties and functions, build a service match engine based on ontology, take a multi-step matchmaking method to implement automatic service discovery. It also describes the architecture and implementation of an e-commerce system prototype based on this solution, and analyses the feasibility of this solution.
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Computer Engineering. 2006, 32(18): 214-216. https://doi.org/10.3969/j.issn.1000-3428.2006.18.077This paper proposes a novel algorithm for image retrieval based on region entropy, which divides an image into higher and lower entropy regions and extracts the color and shape features with each type of regions. The retrieval procedure consists of two steps: first, a simple retrieval algorithm in terms of entropy feature is applied to all the images in the database, and secondly, only the results of the previous retrieval are searched. Experimental results show that the proposed method has sound and robust retrieval performance to the images with simple foreground or complex foreground.
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Computer Engineering. 2006, 32(18): 220-221,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.079How to define and extract the feature of human face is a key and complicated problem. The edge and contour of human face is one of important feature. This paper studies the theory of edge detection and different kinds of arithmetical methods. The experiment results are used to confirm the different methods which are employed to test the edge detection results of the human face image. It discusses the consequence of detection when the threshold is varying and the possible factors, which makes the different results. Finally, it studies the application of the edge detection in human face detection and recognition.
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Computer Engineering. 2006, 32(18): 222-224. https://doi.org/10.3969/j.issn.1000-3428.2006.18.080Lounsbery has brought out a multi-resolution analysis scheme for triangle meshes, but it can only be applied to the regular triangle meshes, and includes a remeshing of the existing 3D data. In order to settle the problem, based on the wavelet, it extends Lounsbery’s scheme. Based on the algorithm, it can directly compress the irregular meshes, and then obtain multi-resolution meshes. In the process, based on the connectivity of the processed meshes, it can also optimize the triangle meshes, make them more regular, and then improve the algorithm. Comparing with previous algorithm, the results prove that the proposed algorithm has good speed, efficiency and practical values.
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Computer Engineering. 2006, 32(18): 225-227. https://doi.org/10.3969/j.issn.1000-3428.2006.18.081Students need to get problem resources that exist largely in Web through a precise and efficient way. But it is difficult for students to get what they really want, which are in correspondence with the knowledge they have already acquired. To solve this problem, this paper proposes a method of retrieving Web problem resources based on ontology and description logics (DL). It adopts OWL to express ontology and use RACER as a DL reasoner to fulfill description logic inferences.
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Computer Engineering. 2006, 32(18): 228-230. https://doi.org/10.3969/j.issn.1000-3428.2006.18.082This paper presents a new multiple description method for coding image. The proposed algorithms are based on a combination of motion compensated temporal filtering technique(MCTF) applied to the construction of some of the most efficient scalable video coding. The result on natural image reveal spatial layer multiple description image coding(SL-MDIC) make use of MCTF. This algorithm improves the performance of the centre channel effectively, and even if only one description is received correctly, the reconstructed image is still acceptable.
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Computer Engineering. 2006, 32(18): 231-233,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.083Multimedia ring back tone (MRBT) service is a value added service which makes multimedia as the ring back tone. An abstract description of the MRBT service using the connection view model (CVM) is addressed with the redefined call party handling mechanism which presents a technology independent service model. The MRBT service described by CVM is mapped to the SIP environment. And a solution of MRBT service in heterogeneous networks is provided according to the model-driven service developing approach.
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Computer Engineering. 2006, 32(18): 234-236. https://doi.org/10.3969/j.issn.1000-3428.2006.18.084High resolution DEM is created based on original topographical maps of reservoir area. After the quality of DEM is approved reliable, topographic factors analysis, visibility analysis and reservoir volume are achieved based on DEM. To obtain and display water information, 3-dimensional visualization system is designed by combining ASP and VRML.
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Computer Engineering. 2006, 32(18): 237-239. https://doi.org/10.3969/j.issn.1000-3428.2006.18.085In order to improve the reusability of submarine combat simulation training system and enhance the interoperation of every simulation part and control part as well as form more reasonable configuration frame, combined with the development of equipment and the reality of combat training of submarine force, according to analyzing submarine real-equipped combat simulation training system with the drive of simulation, based on the mechanism of HLA(high level architecture), this paper puts the emphasis on the M & S research of submarine combat simulation training system.
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Computer Engineering. 2006, 32(18): 240-242. https://doi.org/10.3969/j.issn.1000-3428.2006.18.086With the rapid increases of computer performance in recent years, designers face great challenges such as increasing the frequency and increasing the performance of memory. Compared with the DDR SDRAM, DDR2 SDRAM has higher speed, lower power, higher efficiency and higher stability. A recent statistics shows that DDR2 will become popular in one or two years, but DDR still prevails today. For this reason, this article deals with the design and implementation of the DDR/DDR2 SDRAM compatible controller based on a common standard bus interface.
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Computer Engineering. 2006, 32(18): 243-245. https://doi.org/10.3969/j.issn.1000-3428.2006.18.087In order to reduce accessing delay of the shared main memory sub-system(MMS) of Zhong ke SoC, this paper analyzes the consistence of the timing delay by a behavior model of L*Bus. It reduces the average refuse rate and access delay of the MMS evidently by using the operation queue and the open-page memory controller in the MMS. It also presents a M/M/1/N queuing model for MMS, tests MMS and MMS_E system in the MMSITE , and the result shows that the key parameters of the MMS like accessing delay, total data read and write per second and read /write operation count per millisecond have been improved a lot after the optimization .
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Computer Engineering. 2006, 32(18): 246-247,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.088This paper presents a new control algorithm and VLSI architecture of ECC cryptograph chip, which is based on ECC’s point- multiplication over prime-field. Since modular multiplication is the key operation in point-multiplication, an advanced modular multiplier architecture is introduced based on Montgomery algorithm. The modular multiplier effectively reduces chip’s size and greatly increases chip’s speed. This chip has virtue of small area and fast speed and it is suitable for smart card which has low clock and storage space.
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Computer Engineering. 2006, 32(18): 251-252. https://doi.org/10.3969/j.issn.1000-3428.2006.18.090
A consecutively updated overclustering, self-splitting and merging algorithm based on one-prototype-take-one-cluster(OPTOC) is proposed. It is achieved by constructing a dynamic neighborhood and a distant neighborhood. And using overclustering and merging strategy, it can find natural clusters and give the correct number of clusters. The proposed method is applied to inspect historical datasets, and the results show that the prototypes accord with the corresponding expressions. The method is an effective method for inspect the level of products expression.
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Computer Engineering. 2006, 32(18): 253-254,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.091This paper makes further research on forecasting method of improved exponential curve on the basis of the present document, and presents one new method for estimating the parameters of improved exponential curve. This method combines best optimal method and regression method. By using area search and one dimension search of the optimal theory, a series of can be got; and by using regression method, a series of “ ” and “ ” can be got. When equals the best optimal , and become the best optimal and . The sampling calculation shows that the improved forecasting method is highly precise.
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Computer Engineering. 2006, 32(18): 255-257. https://doi.org/10.3969/j.issn.1000-3428.2006.18.092This thesis introduces the OBC(on-board-computer)of CX-1 micro-satellite, being the first micro-satellite of China under 100 kilogram, the OBC of CX-1 adopts some new fault-tolerant technologies, which improve the reliability of the micro-satellite. It has run normally in orbit over one year, and the reliability of the micro-satellite is verified. The OBC lives through the SEUs(Single Event Upset) many times and still does good job by now. The thesis shows the main characters and the design blueprint of the OBC. The main technology of reliability of the OBC is also projected.
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Computer Engineering. 2006, 32(18): 258-260,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.093This paper provides a Chinese universal input model which can fit almost all kinds of handheld devices. That input model consists of three layers including universal engineering interface layer, universal input stream processing layer and universal data processing layer, and the structure of that model adopts the technique of object-oriented programming. It can be supported by many kinds of OS used in handheld devices, so it is designed to be universal, transparent and expansible. It also introduces each layer of that model and the design technology of each layer, describes the collaborating relationship between all the layers.
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Computer Engineering. 2006, 32(18): 261-263. https://doi.org/10.3969/j.issn.1000-3428.2006.18.094Process, coordination and transaction management mechanism is proposed in order to realize integration of inter-government workflow (IGW) based on Web service of BPEL, WS-Transaction and WS-Coordination. Principle of IGW integration is explained using conception of transaction and an example of Oracle Web service. Steps of IGW integration are described, and IGW integration based on Web service is illustrated by an instance.
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Computer Engineering. 2006, 32(18): 264-266. https://doi.org/10.3969/j.issn.1000-3428.2006.18.095This paper presents an embedded video codec that can be applied to industry scene, the video compression standard is H.264. Based on the PXA255 Xscale processor of Intel and the embedded Linux operating system whose source code is opened, dynamic collection, compression and network transmission of video in real time are achieved, the research process of this system is interpreted, the system’s framework and pivotal technology are offered. By building network test platform, the codec is connected to Ethernet, and the server decoders and playbackes the received video code flow. Test result shows that this codec can be applied to collection, compression and transmission through IP net in real time of the forward-end video in remote video-supervision system.
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Computer Engineering. 2006, 32(18): 267-269,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.096At present e-government system doesn’t realized really one service framework, so one service framework of e-government are analyzed in this paper. It presents a kind of method that applies workflow technology and one service framework into the approval system. A web-based workflow system is designed for controlling business process, which resolves the insufficiency of the tradition approval.
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Computer Engineering. 2006, 32(18): 270-272. https://doi.org/10.3969/j.issn.1000-3428.2006.18.097This paper introduces how to develop waveform based on software communication architecture (SCA) and summaries waveform developing process and API designing principle. Based on engineering practice experience, a whole designing and developing process of demo waveform is shown, including waveform function analysis, module division, API definition and component design. It provides a reference for waveform development based on SCA.
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Computer Engineering. 2006, 32(18): 273-274. https://doi.org/10.3969/j.issn.1000-3428.2006.18.098Computer plays an important role in SINS. The paper presents a computer system for SINS with laser gyro. The system includes a PC104, an interface card and a microcomputer. The software running in PC104 and microcomputer is also introduced. The system cooperates with the laser gyro and other instruments well. The experimental results prove that the system is practical.
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Computer Engineering. 2006, 32(18): 275-277. https://doi.org/10.3969/j.issn.1000-3428.2006.18.099This paper describes the realization of a B2B intermediation e-business platform. The main concern derives from the usage of two emerging technologies, mobile agent and J2EE. It also achieves the design of intermediation agent and the development of agent-J2EE interoperability middleware.
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Computer Engineering. 2006, 32(18): 278-279,. https://doi.org/10.3969/j.issn.1000-3428.2006.18.100The extensible framework provides a uniform rule for software developer, for which the developers may be absorbed in software function and implement. Therefore, the developer may shorter the cycle of development of software and improve software’s transplantation and extension. The paper introduces plug-in, extensible point and the rules finding plug-in, analyses the extensible framework and discusses to develop IDE using Eclipse framework, and the embedded IDE based on Eclipse is implemented.
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Computer Engineering. 2006, 32(18): 280-282. https://doi.org/10.3969/j.issn.1000-3428.2006.18.101A new algorithm is proposed to generate random stitch in embroidery CAD system. Compared with other methods, the distances between the stitches generated by the algorithm are uniform and it can get few intersections between the stitches. The design embroidered by the algorithm embodies the character of the original image better and satisfactory embroidery effects have been obtained.
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Computer Engineering. 2006, 32(18): 283-285. https://doi.org/10.3969/j.issn.1000-3428.2006.18.102This article analyzes the programmable controller programming standard IEC61131-3 software model, designs and realizes control algorithm editor based on the IEC61131-3 standard. Produced its system construction, data exchange mechanism and realization method. This control algorithm editor realizes IEC61131-3 five kinds of programming languages FBD, SFC, LD, STL, IL, supports subroutine and user define function block. Edition, compile, download and debug function are integrated in the software, and online download algorithm and realtime control are easily used for engineer. The software has massively applied in the industry process.
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