05 August 2007, Volume 33 Issue 15
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Computer Engineering. 2007, 33(15): 1-2，32. https://doi.org/10.3969/j.issn.1000-3428.2007.15.001
This paper analyzes Gu’s scheme and proposes a conspiracy attack on it. Using the conspiracy attack, any t (t is threshold value) or more LAs (license authorities) may woke together to reconstruct the secret polynomial of the license and derive the secure share keys of other LAs in P2P networks. They can also impersonate some other LAs to generate a valid partial license and break the protected mechanism of digital content in P2P network. A digital content protected scheme is presented for P2P networks based on Gu’s scheme. The new scheme can achieve all the properties in Gu’s scheme, and withstand the conspiracy attack in Gu’s scheme.
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Computer Engineering. 2007, 33(15): 3-6. https://doi.org/10.3969/j.issn.1000-3428.2007.15.002This paper presents a novel lightweight algorithm of instruction scheduling for reducing the pipeline stalls on RISC micro-architecture with super pipelines. The algorithm is designed for and implemented in a J2ME JIT(just-in-time) compiler in memory constraint and time critical system. It is not based on DAG(directed acyclic graphs) or expression trees, but a novel data structure, namely EDM(extended dependency matrix). The algorithm has strict linear time complexity to the code length in the worst cases. It consumes only about 1KB constant memory space, to fit the small memory footprint for J2ME configurations. This algorithm has been chosen as the default instruction scheduling solution in the JIT compiler by Intel’s high-performance J2ME JVM, namely XORP.
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Computer Engineering. 2007, 33(15): 7-9. https://doi.org/10.3969/j.issn.1000-3428.2007.15.003This paper presents an automatic test data generation tool which aims at generating test data dynamically by reducing the problem of test data generation to one minimizing function. It proposes a new test overage criterion called Length_N and improves the genetic simulated annealing algorithm(GASS), and then the results are used to generate the test data. Experimental results show this tool has better effects.
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Computer Engineering. 2007, 33(15): 10-12. https://doi.org/10.3969/j.issn.1000-3428.2007.15.004The vocabulary carries concrete meaning in the context, so ambiguities occurs. HNC theory puts forward the interactive engine which makes the computer to process natural language like human beings. The disambiguity is also included, which is different from other semantic network methods. Based on overall frame of the HNC theory context hypothesis, this paper elaborates how the computer carries on the disambiguation under the linguistic context frame, and thus enhances the rate of accuracy of the natural language processing. Demonstration shows the method is feasible and realizable.
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Computer Engineering. 2007, 33(15): 13-14，4. https://doi.org/10.3969/j.issn.1000-3428.2007.15.005Fair exchange protocol is the basis of secure electronic commerce where the RSA cryptosystem gains comprehensive applications. This paper presents a new efficient verifiable encrypted RSA signature scheme, on which a simple and practical optimistic fair exchange protocol is been devised. Analysis and comparisons show that this protocol is secure and fast.
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Computer Engineering. 2007, 33(15): 15-17. https://doi.org/10.3969/j.issn.1000-3428.2007.15.006Workflow management system is a complicated information system related to process, data, organizational resource etc. This paper introduces a new type of graphical structure——metagraphs, proposes a holographic workflow model based on elementary activity configurable unit, demonstrates the dynamic configurable characteristic, defines and verifies the correctness of this type of workflow. Experimental results show this method is valid.
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Computer Engineering. 2007, 33(15): 18-19，4. https://doi.org/10.3969/j.issn.1000-3428.2007.15.007One shortcoming of blind signature is that, since the signer’s view is completely shut off from the resulting signatures, the signatures may be used in an unintended way. A generalized Harn partial blind signature scheme is proposed by introducing three random parameters. Three partial blind signature schema were obtained by choosing different parameters and the comparison of their efficiency is given. The security analysis of the proposed schemes is given, which shows they have the properties of completeness, unforgeability and partial blindness. And the proposed schema are against changing agreed information attack because of the employment of Hash function.
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Computer Engineering. 2007, 33(15): 20-22，5. https://doi.org/10.3969/j.issn.1000-3428.2007.15.008This paper analyzes features of scenery image hole-filling manipulation. It builds a special image sample sets, classifies incomplete scenery image by support vector machie (SVM), filles color and texture in the blank hole, and modifies imperceptible color and texture. Theory analysis and experimental results show it has better applied value than several classical methods, such as structure inpainting, texture inpainting and image decomposition.
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Computer Engineering. 2007, 33(15): 23-25. https://doi.org/10.3969/j.issn.1000-3428.2007.15.009Several main data reliability algorithms are described. Encode and decode principles of CRS algorithm used in storage system are analyzed. Principle of realization of data storage middleware based on CRS is presented. Based on CRS and grid technology, a whole structure of a high reliability storage system is proposed. System reliability is proved theoretically. Storage system performance is tested in LAN environment. Results show that the CRS algorithm based storage system not only ensures data storage reliability but possesses high storage performance.
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Computer Engineering. 2007, 33(15): 26-28，3. https://doi.org/10.3969/j.issn.1000-3428.2007.15.010The clustering algorithm is fundamental for constructing gene regulatory network. From a biological view, a cluster of genes may be regulated and may function similarly. But the clustering algorithm can detect the co-regulation genes only, with the causal relation genes not obtainable. On the contrary, it can get the independent conditional probability between variables based on the Bayesian network model, but its application is limited by the computational complexity. For a target gene, its possible parent gene sets are determined by using clustering technique, and a multi-variable nonlinear regression is utilized to model the predictors. Coefficient of determination (CoD) is employed to compute the probability of selecting a parent gene set from all the possible parent gene sets for the target gene. Based on the conditional local causal relation discovery theorem, gene regulatory network can be constructed. Experimental result show that the feasibility and computational complexity of constructing gene regulatory network with the proposed method are superior to that traditional methods.
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Computer Engineering. 2007, 33(15): 29-32. https://doi.org/10.3969/j.issn.1000-3428.2007.15.011An effective link adaptation algorithm based on multi-information fusion is presented for wireless local area network(WLAN), in which the neural network(NN) predictive control algorithm on line and fuzzy logic reasoning and inferring algorithm are adopted to make part judgement about the channel quality based on the channel parameter of signal noise ratio(SNR) and carrier to interface ratio (CIR) and packet error ratio(PER). The best physical layer mode is selected with the decision which is obtained through the synthetic operation and decision rule of the information fusion center. The simulation results show that the proposed algorithm can increase throughput, especially, the network throughput enhances 42.9% and 28.4% compared with the other when the channel quality is bad.
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Computer Engineering. 2007, 33(15): 33-35. https://doi.org/10.3969/j.issn.1000-3428.2007.15.012A method about automata-theoretic model checking is presented. This method is used to verify the property of color Petri nets(CPN) model of interlocking logic. State space exposition can be solved efficiently by constructing linear-time temporal logic(LTL) with labeled generalized Büchi automaton(LGBA) in model checking. This method improves the analysis and checking of CPN. A practical case of the railway interlocking logic is checked by this method.
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Computer Engineering. 2007, 33(15): 36-39. https://doi.org/10.3969/j.issn.1000-3428.2007.15.013Based on the ACO with the iterative pheromone updating for the ship pipe routing design, this paper analyses the influence of the parameters involved in the performance of the algorithm through large numbers of simulation experiments. To obtain a dynamic balance between exploitation and exploration during the evolution, adaptively adjusting parameters with the states of evolution is an effective measure. The results are beneficial to the application and development of the ant colony algorithm in optimization problems.
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Computer Engineering. 2007, 33(15): 40-42,6. https://doi.org/10.3969/j.issn.1000-3428.2007.15.014In order to improve support vector regression(SVR) learning ability and generalization performance, a hybrid selection algorithm for optimizing SVR parameters is proposed. The ranges of the parameters are set according to the information about the training data size and noise level in training samples, and a real-coding based immune genetic algorithm is employed to search the optimal parameters. Hybrid selection algorithm is a precise and efficient method and it need not to consider SVR dimensionality and complexity. Simulation experiments show that the proposed method is an effective approach for SVR parameters selection with good performance on function approximation problem.
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Computer Engineering. 2007, 33(15): 43-45. https://doi.org/10.3969/j.issn.1000-3428.2007.15.015To deal with problems such as fast information retrieval, multi-replica synchronization and so on, a P2P model is presented for distributed collaborative design systems. Some function models, information retrieval models and so on are proposed to construct the system. A P2P information retrieval method based on DHT and interest clustering is used to ensure the fast retrieval of users. And a distributed mutual exclusion algorithm based on DHT is given as the method to synchronize the collaborative data. And the implement method and an instance system are given.
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Computer Engineering. 2007, 33(15): 46-48. https://doi.org/10.3969/j.issn.1000-3428.2007.15.016SPIHT(set partitioning in hierarchical tree) algorithm is a wavelet based zerotree image encoding algorithm known for its high efficiency. However, its high memory requirement and long execute time consumption are obstacles to implement real-time compression. This paper presents a new fast and low memory image zerotree encoding algorithm. This algorithm processes wavelet coefficients of horizontal, vertical, diagonal and low frequency subband respectively, and a nearly optimal bit allocation stage is applied in the above subband to get better compression performance. Experimental results show this algorithm outperforms the original SPIHT algorithm in PSNR and efficiently reduces both the memory requirement and the time consumption.
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Computer Engineering. 2007, 33(15): 49-51. https://doi.org/10.3969/j.issn.1000-3428.2007.15.017The Z Tree supports the searches of rectangle area and the nearest-neighbors (NN) effectively for high-dimensional data sets. The shape variable of nodes is taken into account to optimize the sub-tree’s selection for new data insertion. A new overlap-free split algorithm is proposed to avoid the generation of supernodes. A dynamic pruning and reinsertion policy is used to reduce the number and volume of supernodes. A novel method is introduced to convert a rectangle tree to a sphere tree to speed up the NN search. A new efficient algorithm of the NN search is proposed based on the optimization of search order among sub-trees. The experiments show that the Z Tree is more efficient than X Tree and SR Tree for high-dimensional data.
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Computer Engineering. 2007, 33(15): 52-54. https://doi.org/10.3969/j.issn.1000-3428.2007.15.018Based on to trust management concept and Beth trust model, this paper proposes a new adaptive recommend trust model of Web services, and the corresponding algorithms of its trustworthiness and combine trust, and the punish mechanism for vicious recommendation is provided. The results of simulated experiment show that the model enables the trustworthiness of entities to self adapt with the increase of Web services experience, and punish deceitful entities according to punish mechanism, to some extent, can decrease the number of accessing vicious entities.
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Computer Engineering. 2007, 33(15): 55-57. https://doi.org/10.3969/j.issn.1000-3428.2007.15.019In distributed virtual environment (DVE), the virtual object’s motion information can not be correctly transferred to other nodes of DVE on time for the influence of network defers. For this reason, the traditional collision detection algorithm in DVE, which is based on serial state information, will miss some collision and return incorrect result. This paper demonstrates a new collision detection algorithm that uses swept volume to denote the motion between some key state information in DVE and detect collision using it. This approach can avoid missing detection in the case of network defer or lose, and provide exact detection result.
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Computer Engineering. 2007, 33(15): 58-60. https://doi.org/10.3969/j.issn.1000-3428.2007.15.020This paper proposes centralized and distributed storage models for object-oriented XML. As for distributed storage model, an attribute or element inherited from superclass resides in object of superclass, an attribute or element defined oneself resides in its own object. As for centralized storage model, all attributes and elements reside in their own object, there is not any subclass instance but direct instance in superclass object. The storability of the two models is analyzed by some typical queries. The experimental results show that they are effective and feasible.
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Computer Engineering. 2007, 33(15): 61-63. https://doi.org/10.3969/j.issn.1000-3428.2007.15.021μc/os-Ⅱ(embedded real-time OS)passes FAA safety certification, and has character of open source codes and is free in study. Realization of system modules such as kernel improvement, file system, TCP/IP protocol stack is discussed. This platform provides utilities for application based on μC/OS-Ⅱ and makes the work easier and faster.
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Computer Engineering. 2007, 33(15): 64-66. https://doi.org/10.3969/j.issn.1000-3428.2007.15.022Kinds of requirements information of different stakeholders are identified and expressed independently and decentralized in viewpoint-oriented requirements engineering. To build an uniform specification, it must deal with the integration of viewpoints in last phrase of VORE. Based on the idea and method of problem frame, consistency of viewpoints, integrated manner and integrated process of viewpoints are analyzed and discussed, and a method of integration of viewpoints based on problem frame is proposed.
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Computer Engineering. 2007, 33(15): 67-69. https://doi.org/10.3969/j.issn.1000-3428.2007.15.023The expression model of viewpoint in multiviews-oriented requirements engineering is related to the acquisition and description of requirements information closely, and directly influence the consistency checking and integration of viewpoints. Based on the recent research progress and fruit of software requirements engineering, a new expression model of viewpoint based on problem frame is proposed and its characteristics and application are presented through a case study. Practice shows the model has availability and operability.
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Computer Engineering. 2007, 33(15): 70-71,8. https://doi.org/10.3969/j.issn.1000-3428.2007.15.024Analyzing on the distribute of IP address prefix in core routers, this paper describes an improved algorithm for the longest matching prefix using binary search on hash tables organized by prefix lengths. It uses prefix expansion to reduce the numbers of the prefix length. Thereby, it decreases the number of hash tables and lowered the height of the search tree. The paper provides a concise and utility Marker store algorithm also, and gives some viewpoints for IPv6 routing lookups.
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Computer Engineering. 2007, 33(15): 72-75. https://doi.org/10.3969/j.issn.1000-3428.2007.15.025XML has advantages of expansibility, convenience and self-descriptions, whereas DTD can set up rules for element attribute, element topology structure of XML document. Combined with the predominance of XML and DTD, a method for describing software configuration management information is presented. Meanwhile, the realization of relation storage approach is discussed by way of DTD. Thus the purpose of effective management software configuration information can be attained.
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Computer Engineering. 2007, 33(15): 76-78. https://doi.org/10.3969/j.issn.1000-3428.2007.15.026The data exchange between heterogeneous nodes in the representative instances of data grid has low efficiency. In order to overcome the disadvantage of the data grid, an event-driven based asynchronous message pass model is proposed. The related definitions and the architecture of this model are discussed. The data access middleware of SDG based on this model is also developed. The initial usage shows the event-driven based synchronous message pass model is important for SDG, which has mass data.
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Computer Engineering. 2007, 33(15): 79-82. https://doi.org/10.3969/j.issn.1000-3428.2007.15.027In order to resolve problems in describing platform specific models of MDA, an architecture based modeling approach for J2EE platform specific models is proposed by analyzing and abstracting the common features of the widely-used Web application frameworks on J2EE. Application model built with this approach is composed of three parts: domain component model, action component model and UI presentation component model, which can be transformed into target codes based on many frameworks easily, while containing the specific information on J2EE platform. Based on this approach, the MDA-based development framework is extended by adding abstract platform specific model and concrete platform specific model. The corresponding code-generator’s framework and its realization process are presented briefly.
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Computer Engineering. 2007, 33(15): 83-85. https://doi.org/10.3969/j.issn.1000-3428.2007.15.028Software architecture design becomes a key step of building large, complex management domain specific system, such as human resource management system(HR), office automation system(OA) and customer relationship management system (CRM), while aspect-oriented software development(AOSD) is emerged as a promising approach to solve software complexity. This paper proposes a “4+1” concern view of management domain specific system based on AOSD method. According to the “4+1” concern view, it provides an aspect-oriented software architecture, which is to be implemented by services. The management business support platform constructed based on the proposed architecture and the corresponding development process can be applied to effectively shorten software development cycle, improve software consistency and maintainability and provide better software evolution capability.
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Computer Engineering. 2007, 33(15): 86-87，9. https://doi.org/10.3969/j.issn.1000-3428.2007.15.029The commonly used spatial index algorithms in GIS are introduced, whose performance used in mobile are compared. The limitations of these algorithms when used in mobile GIS are analyzed. A new spatial index algorithm, the dynamic quadtree spatial index algorithm, is presented. Its effectiveness is validated by experiments.
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Computer Engineering. 2007, 33(15): 88-90. https://doi.org/10.3969/j.issn.1000-3428.2007.15.030This paper discusses an implementation framework of abstract data type (ADT), in which application of object technology in implementation of ADT is demonstrated by examples of linear_list. In this framework, an abstract data type is first claimed to be an abstract class, then implemented according to the concrete storage method. Under this implementation framework, the usage of ADT class is independent of the storage method and other implementation details. This framework is adopted in the object-oriented data structure courses, and proved to be efficient and elegant.
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Computer Engineering. 2007, 33(15): 91-93. https://doi.org/10.3969/j.issn.1000-3428.2007.15.031In order to assure Web application’s quality, a high demand for systematic methodologies of Web application test is emerging. As a consequence, model-driven Web application test is proposed. Model is the core of this method. Web application model is built to describe the system under test. Test cases can be generated from the Web application model, and be executed by model-driven test tool automatically. Test results can also be reflected by models. By survey and comparison of the related works, the key technologies to implement model-driven Web application test are summarized. The challenge problems, the potential research directions and the future emphasis are also presented.
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Computer Engineering. 2007, 33(15): 94-95，1. https://doi.org/10.3969/j.issn.1000-3428.2007.15.032To adapt to online detect and restore outliers from data streams efficiently, an online detecting and restoring method for outliers over data streams, called ADR (adaptive detecting and restoring), is proposed. It applies improved Kalman filtering with the amnesia factor to identify outliers at the future timestamp first. And it introduces interpolating wavelet directed by the resolution guider, which determines interpolating resolution based on change speed of data-values, to restore outliers. It adapts to the different requested precision for outliers repairing over evolving data streams well.
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Computer Engineering. 2007, 33(15): 96-97，1. https://doi.org/10.3969/j.issn.1000-3428.2007.15.033There is a parallel sort algorithm of odd sequence. By analyzing, this algorithm is not correct for some odd Bitonic sequences. This algorithm is mended by increasing CCI(compare and conditionally interchange) operations, and any odd Bitonic sequence can be correctly sorted by the mended algorithm. It does not increase memory space. Complication of the mended algorithm does not change.
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Computer Engineering. 2007, 33(15): 98-100. https://doi.org/10.3969/j.issn.1000-3428.2007.15.034Words segmentation recognition and ambiguity resolving are vital factors for information retrieval precision. This paper presents a Chinese word segmentation algorithm with restraint matrix based on the grammar and the semantic. The algorithm improves the accuracy of word segmentation, by combining morphology and syntax with language situation. Continuous character bunch input can be segmented, and then the cut apart word bunch output can be obtained, and one dictionary can be obtained. Then “modern Chinese grammar information dictionary” is used to carry on the processing. Experimental result show the segment accurate rate can enhance about 10%.
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Computer Engineering. 2007, 33(15): 101-102，. https://doi.org/10.3969/j.issn.1000-3428.2007.15.035Simulation is important to test and evaluate a large and complicated system. But because a complicated system is made up of many kinds of elements and each of them has many complicated relations with the others, it is very difficult to give an exact description of it. And in the technique atchitecture of the complicated distrubute simulation, HLA is a very important standard, so how to modeling the system for HLA is the key point. This paper sets forth the modeling method for CGF (computer generated forces) objects based on HLA in the distributed simulation.
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Computer Engineering. 2007, 33(15): 103-105. https://doi.org/10.3969/j.issn.1000-3428.2007.15.036A new event-driven approach for interaction among Java components assembled is presented. This approach has an unified event model, which treats kinds of events with same way, including events triggered automatically, events created explicitly using API, and routing events from event router that reflects router state. It doesn’t need source code modification or taking flexible router network as interaction core. It is thought as a new way to solve component interaction problem.
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Computer Engineering. 2007, 33(15): 106-108. https://doi.org/10.3969/j.issn.1000-3428.2007.15.037This paper studies the implement SQA of CMM Level 2 KPA and software process improvement, and depicts SQA process duty, relation of SQA process and software development process, SQA process implement. SQA is only a KPA of review other five KPA and audit software work product. Due to this supervise, a part of information of software process improvement is from SQA. SQA takes on key affect in whole of software process improvement, SQA plays the role of a bridge in SEPG and software project group.
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Computer Engineering. 2007, 33(15): 109-111. https://doi.org/10.3969/j.issn.1000-3428.2007.15.038Mapping and analyzing the structural properties of P2P overlay network will benefit the further design and development of the P2P network. It seems infeasible to capture a complete and precise snapshot of P2P overlay network due to the variety of P2P protocols and dynamics of the servers. Studying the details of P2P protocols and analyzing the specific P2P overlay network instance becomes an alternative method for this goal. The measured Gnutella network topology is basically taken as an example. The distributed feedback crawling system (called D-Crawler) is presented. The effects of Crawler system parameters on the snapshot accuracy are analyzed. The results show that D-Crawler can achieve accurate and complete topology data of Gnutella overlay network.
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Computer Engineering. 2007, 33(15): 112-114,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.039Linux virtual server is a typical server cluster, which provides high availability through dual load balancer and server pool. When server pool goes wrong, the workload of failure server will be redistrubuted to other available servers by using load distribute algorithm, as a result that server pool has heavy burden, and failure probability of available server increases greatly. High availability N+1 redundancy structure model of server pool is designed and implemented, in order to solve the problems. Experimental results present that the model costs a few system resources and little time in a period of one time takeover.
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Computer Engineering. 2007, 33(15): 115-117. https://doi.org/10.3969/j.issn.1000-3428.2007.15.040Analyzing three overlay constructions of the P2P-based ALM from single-tree, multi-tree to mesh, this paper considers some key problems affecting the multicast performances including the tradeoff between depth and out degree, the available ratio of leaf nodes, and the influence on the churn of overlay. A new P2P multicast algorithm is proposed to solve the impact of heterogeneity in the outgoing bandwidth capabilities of nodes through an adaptive out degree method. The experiments show it can make efficient tradeoff between depth and out degree, increasing the available ratio of leaf nodes.
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Computer Engineering. 2007, 33(15): 118-120. https://doi.org/10.3969/j.issn.1000-3428.2007.15.041In NGN, service management server is one important function entity of service support environment. But it is difficult for the structure and mechanism of current service management servers to support NGN service management requirements. Service management server open architecture is designed based on layered components. Multiple management level control is resolved through policy-based management level control center. A method demonstrated by a simulation experiment is presented to improve execution reliability of service management.
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Computer Engineering. 2007, 33(15): 121-123,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.042As traditional address scanning approach is not available in huge IPv6 address space, this article establishs random address scanning and sample address scanning efficiency models based on IPv6 hosts addresses distribution in address space; By analyzing models and IPv6 network characteristics, a highly efficient address scanning approach based on sampling is presented; Through the test in an IPv6 experiment network, the approach is proved efficient.
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Computer Engineering. 2007, 33(15): 124-126. https://doi.org/10.3969/j.issn.1000-3428.2007.15.043An improved distribute token bucket filter schedule model called dynamic-distribute token bucket filter (DTBF) is proposed to solve the problem of traffic balance and real-time traffic shaping. The algorithm of DTBF in multi-link networks is also designed and implemented for load balance. Simulation experiments and implementation indicate that the DTBF can balance the traffic of multi-uplinks effectively. Bandwidth utilities of links increase, fairness and adaptability are favorable.
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Computer Engineering. 2007, 33(15): 127-129,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.044This paper introduces the FEC system of wireless-MAN(WMAN) standards. Several feasible schema are compared. A simulation system of the downlink of WMAN is constructed for performance analysis. The performance of FEC is analyzed, and the best scheme is presented. The analysis will be an important reference for project application.
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Computer Engineering. 2007, 33(15): 130-133. https://doi.org/10.3969/j.issn.1000-3428.2007.15.045Wireless sensor networks (WSN) are a kind of wireless communication network made by a plenty of fixed nodes which have limited energy store and restricted computing and communication ability. Hence, traditional network layer design and network protocol aren’t applicable in WSN. Based on the spirit of traditional network layer design, a new cross-layer network model is proposed. The new model is realized in OPNET in which typical applications of route selection and data collection are simulated. The result shows that new cross-layer model can well describe the function of each layer and make network protocol design more concentrative and synthetical.
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Computer Engineering. 2007, 33(15): 134-136. https://doi.org/10.3969/j.issn.1000-3428.2007.15.046Administration of domain name service supplied by BIND is always completed manually, and statistics characteristics of users’ access to domain names and amount of access is difficult to calculate. Based on BIND running on Solaris 9, the management and configuration of BIND is given in the Web application, and by analyzing BIND source code, a real-time statistics method of user access to domain names is given instead of traditional BIND log stored in file system, an efficient domain name statistics method in memory is put forward.
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Computer Engineering. 2007, 33(15): 137-138,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.047Recently, there are many difficulties in stream media transmission over the Internet, because massive media files transmission needs high bandwidth, and if there is no corresponding conditions in Internet, it may lead to throw the packages and network delay, which can reduce the quality of stream media. This paper introduces a stream media high quality transmission strategy, which can reduce the package of frequency and guarantee reliable stream media transmission by mistake check and congestion control.
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Computer Engineering. 2007, 33(15): 139-141. https://doi.org/10.3969/j.issn.1000-3428.2007.15.048Based on the development of access convergence router (ACR)of National 863 Plan，this article puts forward a scheme using FPGA to implement the design of embedded Tri-mode Ethernet(10MB/100MB /1 000MB), introduces a way of using FPGA to design embedded hardware and software system, and programs a controlling system for auto change among 10MB/100MB/1 000MB . Such design is realized in project.
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Computer Engineering. 2007, 33(15): 142-143,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.049Although every working principle and realizing way affecting on system security is different, their bottommost action is reading and writing the system files in the performing process. Through strict control on illegal access to system files, a protective technology based on file access interdiction is put forward and its protection extension, protection time, protection strategies and protection effect evaluation are studied and analyzed systematically to build the final security line for the local computer systems.
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Computer Engineering. 2007, 33(15): 144-146. https://doi.org/10.3969/j.issn.1000-3428.2007.15.050This paper describes the principle of the mechanism of certificate revocation based on OCSP, and proposes a policy evaluating model focusing on the single service mode of OCSP. The model based on queuing theory simplifies and abstracts the mechanism. According to the model, the revocation policies about OCSP are evaluated, and several parameters effecting on the system such as queuing time, net bandwidth and verifying velocity are discussed. And it analyzes multi-service model.
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Computer Engineering. 2007, 33(15): 147-148,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.051A natural language sentence can be transformed into a word tag string or a sentence pattern. This paper proposes a new information hiding algorithm based on Huffman code. The algorithm constructs code of patterns according to their distribution and transforms the secret message into a pattern by Huffman decoding and then computes the secret key of position which pattern appears in the cover text. Hidden message can be extracted by Huffman compression. The capacity of information hiding is also formulated. In the new scheme, text document doesn’t need any modification.
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Computer Engineering. 2007, 33(15): 149-151. https://doi.org/10.3969/j.issn.1000-3428.2007.15.052In wireless sensor network(WSN), network secure communication is getting high status in network communication area. Due to the special properties of WSN, such as large scale, low resource, distribution and so on, this paper puts forward a new protocol——polynomial key distribution protocol for these characteristics, and also describes the particular design flow and special advantages. This project is realized in TinyOS system by code design.
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Computer Engineering. 2007, 33(15): 152-154. https://doi.org/10.3969/j.issn.1000-3428.2007.15.053To solve the problem of computer security, this paper puts forward a new computer architecture based on TPM chip by designing a software protocol stack TSS based on security chip. By using this protocol stack to call kernel service modules through API, the problem of trusted platforms in distance communication can be solved. In the security chip based on TPM, authorization and authentication management based on multi-protocol are designed and implemented to realize authorized communication and authentication between upper application and TPM, ensuring that the computer is able to accomplish the task of safe computation and safe store to enhance the security level of the computing platforms.
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Computer Engineering. 2007, 33(15): 155-157. https://doi.org/10.3969/j.issn.1000-3428.2007.15.054Through the cryptanalysis of an E-cash system with multiple banks based on proxy signature proposed by Zhou etc., it is found that thecentral bank or the third trustee can issue valid E-cash by imitating other legal banks. An off-line E-cash system with multiple banks based on ellipticcurve is proposed using the technique of proxy-protected proxy signature. The E-cash’s denomination is marked with authorization in this E-cashsystem, and the analysis shows that it overcomes the disadvantages of those existing E-cash systems with multiple banks, and has higher efficiency.
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Computer Engineering. 2007, 33(15): 158-159,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.055Conic curve cryptosystem is a new public-key cryptosystem, the parameters selection of conic curve could affect the security of conic curve cryptosystem. The reason that security deterioration in the case of unsuitable parameters are selected over conic curve is analyzed, and the algorithm of generating a secure conic curve equation based on finite field Fp or ring Zn is given. It expands the definition of conic curve group which is proposed by Zhang Mingzhi, and the new equation could be applied on the finite field whose characteristic is 2.
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Computer Engineering. 2007, 33(15): 160-162,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.056Response decision is key to intrusion response. Based on the analysis of existing intrusion response decision models, a novel response decision model based on effect evaluation feedback is proposed. Analysis of an example is also presented, by which the accuracy and adaptation ability of the model is proved.
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Computer Engineering. 2007, 33(15): 163-164,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.057A new efficient multiple micropayment scheme named MicroPay is proposed. Its workflow is introduced and its security and performance are analyzed from various aspects. MicroPay reduces the times needed to sign or certificate and cancels many operations on Hash. It improves efficiency of the system, end insures equality of the system and the integrity and non-repudiation of data.
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Computer Engineering. 2007, 33(15): 165-166,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.058Concealment technology is critical to a Trojan Horse, which decides the survivability ability of the Trojan Horse. The concept of port reuse is brought forward for the common disfigurement of the Trojan Horse in concealment technology. And a Trojan Horse without process or port reuse is made in the lab. The Trojan Horse can insert a layered service provider in operating system by making use of new characteristics of WinSock 2 of Windows, thus it will get the control of the operating system and communicate with outside in an open legal port when network application program makes a call of WinSock 2. For the Trojan Horse which does not have to open a new port in comparison with traditional ones, its concealment ability is stronger.
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Computer Engineering. 2007, 33(15): 167-169. https://doi.org/10.3969/j.issn.1000-3428.2007.15.059Network intrusion detection data are made up of multi-class attacks data and normal data. The application of multi-class support vector machine(SVM) for network intrusion detection is researched. The multi-class support vector machine is designed to detect network intrusion by using one-against-one method. The designed SVM classifier is evaluated with KDD99 intrusion detection dataset, the results obtained are compared with BP neural networks. Experimental results show that classifier based on multi-class SVM is effective and efficient.
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Computer Engineering. 2007, 33(15): 170-171,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.060By utilizing the immunity theory, the immunity operator can restrain the degenerate phenomenon during the evolutionary process. This paper designs a novel immunity genetic algorithm: the “blind mutation operator” is substituted by the “guided mutation operator”, which is immunity operator. By changing the probabilities of crossover and immunity, it examines the role of crossover and immunity operator in immunity- evolutionary algorithm with the examples of traveling salesman problem. The experimental results validate the constructive aspect of crossover and local search ability of immunity operator to restrain the degenerate phenomenon of crossover.
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Computer Engineering. 2007, 33(15): 172-174. https://doi.org/10.3969/j.issn.1000-3428.2007.15.061The is paper presents a novel online detection method towards the outlier in data stream. The method is referred as online detection towards outliers in data stream(ODODS). The method is partially inspired by the density based clustering and uses improved adaptive particle swarm optimizer(IAPSO) for detecting the outliers. Results of experiments implemented in intrusion detection domain prove the efficiency of ODODS.
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Computer Engineering. 2007, 33(15): 175-177. https://doi.org/10.3969/j.issn.1000-3428.2007.15.062In order to avoid the limitation of the existing segmentation algorithms based on gray-scale image or binary image, this paper presents an approach of handwritten characters segmentation which makes use of the characteristics of gray-scale image and binary image. The characters image is divided into some segmentation regions, each of which contains a segmentation path. Viterbi algorithm is employed to detect the non-linear segmentation path in each region for separating the connected characters. The algorithm performs the search process by combining the information of gray scale and binary images. Experimental results show the proposed approach is effective for handwritten characters segmentation.
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Computer Engineering. 2007, 33(15): 178-180. https://doi.org/10.3969/j.issn.1000-3428.2007.15.063Web page categorization has become popular with the fast growing of Internet. Because of the disadvantages of traditional statistical approach, this paper proposes a categorization method based on fuzzy comprehensive evaluation. Due to the complexity of natural language and uncertainty of comprehension, the Web page belongs to every class with its probability, which can reflect the true information. According to the probability, users can deal with the Web pages flexibly to satisfy their needs.
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Computer Engineering. 2007, 33(15): 181-183,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.064Supporting QoS and improving bandwidth utilization are necessary in IP/DWDM optical Internet. This paper with the introduction of game theory and layered graph, proposes a static traffic grooming scheme based on artificial immune algorithm to minimize network resource occupancy and maximize comprehensive QoS satisfaction degree, achieving Nash equilibrium between network provider utility and user utility. Simulation results show that the proposed scheme is both feasible and effective.
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Computer Engineering. 2007, 33(15): 184-186. https://doi.org/10.3969/j.issn.1000-3428.2007.15.065The current research status of rough set reduction is reviewed, and a new rough set reduction algorithm based on the quantum genetic algorithm(QGA) is proposed, which is free from the disadvantages in genetic algorithms from the respect of recursion and convergence performance. With a new type of discernibility matrix adopted, the algorithm exhibits excellent capabilities in attribute reduction of inconsistent decision table; a new parametric configuration scheme for the fitness function is proposed, which can be used as a reduct admissibility criterion. It has been validated experimentally that the proposed algorithm is superior to the conventional GA-based algorithm in terms of convergence and speed.
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Computer Engineering. 2007, 33(15): 187-189,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.066This paper proposes a fast Pareto genetic algorithm for searching pareto optimal solution set. It is based on a new approach for fast evaluation of fitness of individuals and a clustering based external population update scheme for maintaining population diversity and even distribution of Pareto solutions. Experiments on a set of multi-objective knapsack optimization problems shows that FPGA can obtain high-quality, well distributed non-dominated Pareto solutions with less computational efforts compared to other state-of art algorithms, it has advantages in its convergence speed and quality over the state-of-the-art SPEA algorithm.
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Computer Engineering. 2007, 33(15): 190-192. https://doi.org/10.3969/j.issn.1000-3428.2007.15.067Aiming at the problem of low classification accuracy caused by poor distribution estimation for training naive Bayes text classifier on word clusters, a word list based on mutual information between word and clusters is made, a sample set with the same size with bootstrap method is constructed, and the average of the parameters estimated from it as the last parameter to classify unknown text is used. Experiment results on benchmark text dataset show that the method gain higher classification accuracy compared to naive Bayes classifier.
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Computer Engineering. 2007, 33(15): 193-195. https://doi.org/10.3969/j.issn.1000-3428.2007.15.068To meet the fast decision-making of modern warfare, an algorithm for group of targets recognition in battlefield is proposed, which is based on cluster thought. By cluster method of dissimilarity analysis, this algorithm makes use of the characteristic measure of location, speed and direction of targets to recognize groups of targets in battlefield. The advantage of the algorithm is its low complexity, much higher recognition accuracy rate and much more robust handling for outlier. The algorithm can satisfy the real time requirement in battlefield. Simulation experiments demonstrate that the algorithm can accurately recognize the group of targets in battlefield with higher probability and provide direct support for fast decision-making of battle and programming of tactics.
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Computer Engineering. 2007, 33(15): 196-198,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.069
This paper suggests and proves two properties of circle’s Freeman chain code, the four odd numbers of eight-direction chain code are equal and also even number, the Freeman cycle chain code and its symmetric cycle chain code is the same. The new circle recognition algorithm based on Freeman chain is proposed, which only needs two parameters: the dissimilarity of eight-direction chain code, and the similarity of Freeman chain and its symmetric chain. Experiment results show that the method can recognize accurately the circles with high efficiency.
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Computer Engineering. 2007, 33(15): 199-201. https://doi.org/10.3969/j.issn.1000-3428.2007.15.070It is an important technology to classify emails by using text and appendix information in the field of email processing. This paper presents an intelligent email classification system based on PIM and keywords. Keywords are used as the input features of native Bayes classifier to filter text of email. PIM is used as the statistical feature to classify images in appendixes. Experiments show that this system is efficient in intelligent emails classification.
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Computer Engineering. 2007, 33(15): 202-204. https://doi.org/10.3969/j.issn.1000-3428.2007.15.071For the complexity of document images, this paper proposes a method based on page’s layout foreground and least square method. In this method, foreground pixels are described by special patterns. Halftones, graphics and forms are excluded from the document images by pattern classification. The biggest pattern structure is obtained after merging the rest character pattern. The skew angle is counted by using the least square method according to the points, which is obtained by searching the biggest pure text pattern structure. Experimental result shows the fastness and effectiveness of the proposed algorithm. A most prominent superiority of this method is that patterns obtained in the process of skew angle detection can be used for further layout analysis.
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Computer Engineering. 2007, 33(15): 205-206,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.072Aiming at problem of packets loss, this paper proposes a method of lost packets compensation based on Lagrangian interpolation and a new classifier GMM-DM. The algorithm improves performance of GMM classifier when training data is inadequate due to the packets loss during transportation. Experiments show that compensation based on Lagrangian interpolation and GMM-DM new classifier could obtain better results than traditional methods when the ratio of lost packets is relatively high.
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Computer Engineering. 2007, 33(15): 207-208,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.073This paper puts forward a distributed intelligent suggestion system based on mobile agent and Web services and constructs the architecture of the system. It narrates workflow of the system and explains algorithms implementing main functions of the system.
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Computer Engineering. 2007, 33(15): 209-210. https://doi.org/10.3969/j.issn.1000-3428.2007.15.074This paper proposes an improved quantum delta-potential-well-model particle swarm optimization (QDPSO) algorithm based on simulated annealing (SA) theory. The strong searching ability of SA is employed to overcome the precocious shortcoming of QDPSO, and a performance test according to benchmarks functions is taken to confirm astringency and rapidity of the algorithm compared with SPSO and QDPSO. Simulation results show that the algorithm with better stability and astringency is an excellent global optimization method.
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Computer Engineering. 2007, 33(15): 211-213. https://doi.org/10.3969/j.issn.1000-3428.2007.15.075For sustainable development of cage culture, the environmental risk and main affecting factors are revealed based on the pollution characteristics. For evaluation of the risk in aged cage culture areas, rough set theory is emerging as a powerful tool for reasoning about data. This paper introduces a method for mining risk rules using variable precision rough set(VPRS) model. It presents concepts about Pawlak rough set and variable precision rough set, describes the aging degree and risk grade quantitatively according to the standards about fishery environment. A method for risk rules mining in aged cage culture based on variable precision rough set is given.
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Computer Engineering. 2007, 33(15): 214-216. https://doi.org/10.3969/j.issn.1000-3428.2007.15.076Test-cases are currently designed manually in the process of software testing. There are much repetitive work and low test efficiency with this method. Therefore, this paper presents an agent model based on the ideal of BDI agent. This model can automatically design testc -ase in black _box testing based on the principals of designing test-case and the functions of module to be tested, it solves the traditional deficiency in black_ box testing.
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Computer Engineering. 2007, 33(15): 217-219. https://doi.org/10.3969/j.issn.1000-3428.2007.15.077Text classification is the foundation and crucial problem of text data mining, it is an application based on the technology of natural language processing and machine learning. Feature extraction and categorization algorithm are the most crucial technologies for this problem. This paper proposes that latent semantic indexing (LSI) is used for feature extraction and dimensionality reduction, support vector machine(SVM) is used for text classification. The result shows that compared with the classifier based on vector space model combined SVM and the classifier based on LSI combined K-nearest neighbor (KNN), better performance is acheived. It shows that while the number of categories is small, and the categories are divided distinctly, the method can be used for practical application.
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Computer Engineering. 2007, 33(15): 220-221,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.078This paper analyzes how the frame based video codec structure undermines the real-time performance of audio codec and communication module in embedded multimedia communication platform, and proposes a design solution based on finite state machine(FSM) using state converting graph. The experimental results demonstrate that the FSM control flow improves the system real-time performance obviously.
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Computer Engineering. 2007, 33(15): 222-223,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.079This paper designs a set of high cost-performance home media entertainment center(HMEC) based on network processor IXP425 and sigma EM8622 architecture, which can seamlessly join all kinds of consumer electronic products in the family. It can manage diversified multimedia file and provide automation control and remote management through Internet. The system fully meets the needs of data shared among internal data, external Internet data and media flows in home digital media.
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Computer Engineering. 2007, 33(15): 224-226. https://doi.org/10.3969/j.issn.1000-3428.2007.15.080
Motion estimation and motion compensation plays a key part in electronic image stabilization system. In order to improve performance of motion estimation and to reduce the burden of computer for real time application, this paper presents a new global motion estimation algorithm called step global motion estimation based on macro block algorithm (SGMEMB). It also develops the motion estimation and motion compensation skeleton, which is used in electronic image stabilization system, on which the stable image sequence by using a new two step motion compensation algorithm (TSMC) is obteined. The simulation results show that the method applied to electronic image stabilization system is efficient and feasible.
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Computer Engineering. 2007, 33(15): 227-229. https://doi.org/10.3969/j.issn.1000-3428.2007.15.081This paper proposes a test model and implement scheme of microprocessor interface unit. Random test method is adopted in this model, and constrained random test is used in stimulus generation. Experimental results show that the constrained random test model can achieve 83.68％ functional coverage and accomplish functional verification of microprocessor interface unit efficiently.
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Computer Engineering. 2007, 33(15): 230-231. https://doi.org/10.3969/j.issn.1000-3428.2007.15.082To overcome the platform dependence and firewall barrage in remote test and diagnosis software, this paper develops the remote test and diagnosis software with HTTP-based Web services instead of traditional components. On the base of the hardware platform fitting for equipment remote test and diagnosis, it introduces the principle of service-based remote test and diagnosis software. The platform dependence and firewall are solved in remote test and diagnosis software.
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Computer Engineering. 2007, 33(15): 232-234. https://doi.org/10.3969/j.issn.1000-3428.2007.15.083Based on networked manufacturing integration platform, a structure of service navigation system is presented with work flow as the focus. Three core arithmetics of the main modules of this system including affair process analysis processor, work flow execution processor and result file manager are designed and realized, to effectively overcome the defects of the traditional navigation system such as close coupling software development mode, P2P integrated mode and the mode with the center of procedure. This service navigation system can successfully solve retrieval of networked manufacturing resource knowledge and potential partners, and greatly strengthens the flexibility and agile response of networked manufacturing system.
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Computer Engineering. 2007, 33(15): 235-237,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.084WLAN card has the ability of sending and receiving datum wirelessly, and data processing to some extent. The embedded wireless local area network adapter which includes microprocessor, WLAN card, radio parts etc, possesses stronger competence of data processing by corresponding development of software and hardware. It can excuse the trouble of mounting WLAN card’s driver, so it can plug and play. The embedded wireless local area network adapter not only is fit to PC and notebook, but also can be used by embedded device’s wireless communication.
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Computer Engineering. 2007, 33(15): 238-240. https://doi.org/10.3969/j.issn.1000-3428.2007.15.085This paper presents a new transaction-level verification model based on the SystemC verification library (SCV), and discusses some details about the key modules. It is easier and more effective to build a functional verification testbench which enables transaction recording, self-checking and random-constrained. A case study from a RAM design is used to show the effectiveness of the approach.
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Computer Engineering. 2007, 33(15): 241-242,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.086In order to improve Matlab/RTW ’s deficiency in hardware programming, C-MEX function is used to make the hardware driver. Based on remote network closed loop control system, the purpose of expanding the capacity of Matlab for hardware programming can be reached as the following: translate and edit to generate DLL file, use the S function of Simulink to transfer DLL file, and use RTW to generate C code, then download the created C code to remote network controller and field controller based on ARM technology. Thus, expected results of online remote control in real time can be achieved.
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Computer Engineering. 2007, 33(15): 243-245. https://doi.org/10.3969/j.issn.1000-3428.2007.15.087In order to meet the high precision requirements of stepper motor in radar antenna control system, this paper designs a method to test motor and its special driver. It not only introduces a kind of basic method for serial communication with Matlab, but also gives software design of serial communication between PC and the test-platform which is based on the Synchro & Digital converters and its drivers under the environment of Matlab, and processes the real-time measured data of motor. With the analysis of the driver’s performances, the best sub-divisible plan can be choosen, and it improves the angle accuracy of the radar antenna rotation.
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Computer Engineering. 2007, 33(15): 246-248,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.088RTS games are difficult in programming, complex in world reappearance, hard to behave the roles and require rigorous perfect performances. Aiming at reducing difficulty of game development and improving the efficiency, the paper puts forward a method to use Flash as graphic engine. Based on this method, with the combination of OOP programming and OOD designing, following the Flash game development strategy, it accomplishes a practical archetype of RTS game. The research and experiment show it is feasible that use Flash as graphic engine in R&D of mercantile RTS games.
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Computer Engineering. 2007, 33(15): 249-251. https://doi.org/10.3969/j.issn.1000-3428.2007.15.089As the extension of e-business, mobile business is developing rapidly. This paper designs a location-based model of mobile advertisement and evaluates it. The model will develop the application of the mobile advertisement and increase the pertinence and veracity of the mobile advertisement.
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Computer Engineering. 2007, 33(15): 252-254. https://doi.org/10.3969/j.issn.1000-3428.2007.15.090To solve the difficult manual signing-up, examination signing-up system for Hong Kong, Macao, Taiwan and oversea Chinese examinee is developed with the help of Guangdong examination center. This paper analyzes the system development environment, the flow of signing-up and the module’s function of signing-up system, discusses 3 key technologies, i.e. the transform between gb2312 and big5, Web cache and taking pictures via the Web.
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Computer Engineering. 2007, 33(15): 255-257. https://doi.org/10.3969/j.issn.1000-3428.2007.15.091Since most network behavior audit software can not record the files sent through MSN, a new network behavior audit system is presented which can intercept instant messages and files sent by MSN users. As MSN file packets are captured, the ACK number and SEQ number are analyzed. Then, the packets are put in order and reassembled to recover the original file. This system can be applied to other network transmission protocol such as HTTP and mail delivery.
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Computer Engineering. 2007, 33(15): 258-260. https://doi.org/10.3969/j.issn.1000-3428.2007.15.092This paper studies medical data grid to meet the requirement for common sharing of distributed medical images data resources and medical apparatus. And it designs the architecture of medical data grid, discusses the standardization of medical images data, and implements a database for medical applications. This paper also describes the research on resource management, registration and researching, work flow management, data management and security. The practice shows, the medical data grid testbed GADITMER can improve the clinic diagnosis and epidemiology research.
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Computer Engineering. 2007, 33(15): 261-263. https://doi.org/10.3969/j.issn.1000-3428.2007.15.093According to the framework of wavelet transform, the FPGA architecture design of 2D-lifting wavelet transform based on JEPG2000 is proposed, which works based on row scan fashion for input. The whole architecture is optimized in time division multiplex (TDM) and the pipeline designs and takes full advantage of the memory bits in FPGA, which leads to row and column processor work in parallel way. Multiplication is substitute for shift-add operations to get higher hardware utilization and speed. The SDRAM controller realizes seamless buffering between FPGA and SDRAM with ping-pong operation, which can ensure multilevel transform achieve high-efficient, real time and parallel pipelined output. Simulations illustrate that it possesses strong processing ability and low power consumption in real time image processing and creates good condition for coding and transmission.
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Computer Engineering. 2007, 33(15): 264-266,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.094ARM architecture-based 32-bit microprocessor is applied widely. The design of hardware and software of an image recognition system based on 32-bits ARM microcontroller S3C2410 is discussed through a representative example, and the use of embedded operating system Mizi Linux is introduced combined with its practical application. It describes the programming of low level driver, the high level trademark recognition algorithm design, the implementation of hardware platform and study of the system portability.
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Computer Engineering. 2007, 33(15): 267-268，. https://doi.org/10.3969/j.issn.1000-3428.2007.15.095With the change of network structure and more factual applications for WebGIS, the traditional development of WebGIS faces challenge. By introducing and analyzing architecture and operation mechanism of J2EE and ArcIMS, the paper studies design architecture and system function of the WebGIS which is developed based on J2EE and AcrIMS. Taking the system as an example, key technologies of providing geo-spatial service and non-spatial service with EJB control are explained.
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Computer Engineering. 2007, 33(15): 269-271. https://doi.org/10.3969/j.issn.1000-3428.2007.15.096Accessing the enterprise information system at any time and any where is the potential requirement with the development of wireless network and 3G. The paper discusses a common framework of mobile information platform. The key technology and implementation principle are discussed and a general model is given for anyone constructing a enterprise mobile information system. For adopting a new method and synchronization technology, the module can make the system practicality and real “unwired”.
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Computer Engineering. 2007, 33(15): 272-274,. https://doi.org/10.3969/j.issn.1000-3428.2007.15.097The prison information system is characterized by many modules, large number of users, frequent staff changes and information confidential. According to these characteristics, this paper proposes one kind of synthesis access control model and provides the model formalized description. This model organically unifies the MAC, RBAC and TRBAC, with the characteristics of strong controllability, easy authorization management. Using this model, it designs the authority management subsystem, and some implementation of authority management in the system are provided to solve the complex access control problem in the prison system.
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Computer Engineering. 2007, 33(15): 275-276. https://doi.org/10.3969/j.issn.1000-3428.2007.15.098Against problems faced when developing GUI application on embedded linux platform, this paper discusses how to deploy Chinese environment for Qt/E Chinese display and how to make the Qt/E library support touch panel, mouse and keyboard at the same time by revising source code.
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Computer Engineering. 2007, 33(15): 277-279. https://doi.org/10.3969/j.issn.1000-3428.2007.15.099This paper designs and implements a WebMail system based on FreeBSD4.9 Unix operation system. It applies Qmail to MTA program and MYSQL to storage system. Developed by C++, it is a set of feasible mail server system with high dependability, convenient installation, management and maintenance, high security and efficiency, and high performance cost ratio. This system has been already adopted in some enterprises and institutions. It will have a good market prospect.
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Computer Engineering. 2007, 33(15): 280-282. https://doi.org/10.3969/j.issn.1000-3428.2007.15.100This paper puts forward the layering rule of a city transportation network from qualitative angle and realized hierarchy of the transportation network by using vector data of Xi’an transportation network. To lay the foundation of designing and realizing the hierarchical optimal path algorithm based on Oracle 9i space database, the loading and accessing technique to the space database were summarized and some programs to access the space database were explained.
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Computer Engineering. 2007, 33(15): 283-285. https://doi.org/10.3969/j.issn.1000-3428.2007.15.101Online games are very popular now in China, among which the chess/cards online game is one of the hottest. But there are few papers about how to develop an online game. Based on the work on the practical project, this paper presents a universal server architecture for chess/cards online games. The architecture, communication protocol, multi-thread model and interface for third-party of this server are discussed. It analyzes the overall architecture of the game server.
2024
Volume 50 No 3
Volume 50 No 3
(Started in 1975, Monthly)
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428