05 December 2007, Volume 33 Issue 23
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Computer Engineering. 2007, 33(23): 1-2,15. https://doi.org/10.3969/j.issn.1000-3428.2007.23.001
A novel secure multiple QoS guaranteed multicast routing protocol for Ad hoc networks NSQMRAN is presented, which uses NTRUSign as cryptographic mechanism to sign the route massages. NSQMRAN enhances the security with source authentication mechanism and provides such security services as reality, integrity and non-repudiation for the QoS multicast route messages in Ad hoc networks to guard against the attacks caused by malicious nodes. And the main simulating on results based on NS2 shows that compared with other protocols which use RSA as public key cryptographic algorithm, the performance of NSQMRAN protocol based on NTRUSign is better and it causes less delay of end to end.
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Computer Engineering. 2007, 33(23): 3-5. https://doi.org/10.3969/j.issn.1000-3428.2007.23.002Some optimizations may be applied to a specific algorithm, but they are inadequate to other algorithms in system. Based on hierarchical linear structure and regular blocks, this paper presents a virtual octree model without any pointer or location information in octants. The new model has high efficiency both on access and storage, and unifies the pointer-based octree and the linear octree. The virtual octree model represents the solid and its inner attributes, and also keeps high performance of visualization and analysis, and has wide applications in GIS and other areas related to volume graphics.
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Computer Engineering. 2007, 33(23): 6-8,11. https://doi.org/10.3969/j.issn.1000-3428.2007.23.003Rather than C language, C++ is chosen as the language working in Linux kernel with the purpose of realizing object-oriented design and programming in kernel environment. However, it is a challenge that how to keep the compatibility between Linux kernel and C++. This paper analyzes the mechanism of kernel modules loading. Also the measure of memory allocation adopted by C++ in the kernel is discussed. As a result, it finds a feasible way to apply C++ language to kernel modules development.
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Computer Engineering. 2007, 33(23): 9-11. https://doi.org/10.3969/j.issn.1000-3428.2007.23.004(1. Guangdong Key Laboratory of Computer Network, South China University of Technology, Guangzhou 510640; 2. Guangdong Province Key Laboratory of Information Security, Sun Yat-sen University, Guangzhou 510275; 3. National Key Laboratory of Integrated Server Networks, Xidian University, Xi’an 710071)
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Computer Engineering. 2007, 33(23): 12-15. https://doi.org/10.3969/j.issn.1000-3428.2007.23.005In classical ID3 algorithm, “information plus” is regarded as illuminative information in selecting examing attribute. But it has the insufficiencies. In order to solve it, this paper brings forward cognitive entropy concept and information compensation concept, makes thinks of compensative information of the attribute as illuminative information, and designs a kind of CID3 algorithm based on compensative information. Aanalysts a great number of instances testify that CID3 algorithm has much more priority than ID3 algorithm.
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Computer Engineering. 2007, 33(23): 16-18. https://doi.org/10.3969/j.issn.1000-3428.2007.23.006In order to achieve cluster analysis with unknown number of clusters, this paper proposes a fast dynamic clustering algorithm based on clone selection, which is inspired by the clone selection principle of the vertebrate immune system and combines the cluster validity analysis. It not only adaptively determines the amount and the center’s positions of clustering, but also avoids the local optima and the flaw about sensitive to the initialization. The convergence speed of this algorithm is improved obviously through introducing a new search operation and selecting appropriate initial clustering center. Experimental results indicate the validity of the proposed algorithm.
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Computer Engineering. 2007, 33(23): 19-21,2. https://doi.org/10.3969/j.issn.1000-3428.2007.23.007The state-of-art features extraction methods from time series are single-scale methods that result in the location of features imprecision and suppress the quality of discovered pattern. A novelty multi-scale features extraction methods from time series is proposed based on the principle of wavelet singularity detection. The time series are compressed into event sequence using singularity features and a dynamic time warping similarity measure of event sequenced is defined. The proposed algorithm is used to similarity pattern matching for event sequence. The experimental result shows that it has higher matching precision and lower computing cost.
【Key words】time series; similarity matching; singularity event; knowledge discovery
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Computer Engineering. 2007, 33(23): 22-24. https://doi.org/10.3969/j.issn.1000-3428.2007.23.008The Perona-Malik model is a classical method of anisotropic removing noises. It has the advantage of remaining the edge map of image. The negative gradient of restored image by Perona-Malik model is defined as external forces, and the segmentation results that affect active contour model are studied. Accordingly, an external force field for active contour model——PMF is presented. Theoretical analysis and experimental results show that PMF can retain the edge information of image and enter the edge’s concaves entirely. PMF has large capture range with few restrictions to initial curves. Moreover, because PMF is derived from Perona-Malik, it is robust to the noise.
【Key words】active contour model; PMF model; anisotropic diffusion; image segmentation
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Computer Engineering. 2007, 33(23): 25-27. https://doi.org/10.3969/j.issn.1000-3428.2007.23.009This paper investigates the semi-blind multiuser detection for multicarrier CDMA (MC-CDMA) uplink, improves Chebyshev approximation implementation of the minimum output energy (MOE) blind multiuser detection and proposes an adaptive semi-blind multiuser detection algorithm based on subspace tracking and Chebyshev approximation for MC-CDMA uplink. On the basis of MOE linear detector, it designs a semi-blind multiuser detector based on the MOE principle by making use of the spreading sequences of all known users and effectively eliminates multiaccess interference. In order to reduce the computational complexity, the improved PASTd algorithm is applied to Chebyshev approximation algorithm to estimate the optimal weight vector of MOE semi-blind multiuser detector. The proposed algorithm has the low computational complexity, and excellent capability of eliminating multiple access interference and good detection performance. Simulation results are presented to demonstrate the superiority and feasibility of the proposed algorithm in practical applications.
【Key words】semi-blind multiuser detection; Chebyshev approximation algorithm; minimum output energy(MOE); multicarrier
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Computer Engineering. 2007, 33(23): 28-30. https://doi.org/10.3969/j.issn.1000-3428.2007.23.010
In order to design digital signal processor with own property right, one kind of pipeline structure of floating point digital signal processor based on VelociTI architecture is studied and a new processing method for pipeline exception is proposed. Abnormal things affecting pipeline are classified reasonably. Pipeline registers’ clock signals of pipeline registers are controlled for memory blocking, many execute packets, many cycles NOP instructions. Some instructions should be disabled when interruption occurs, this work is done by controlling execute condition of these instructions. The correctness can be confirmed by simulation results.
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Computer Engineering. 2007, 33(23): 31-34. https://doi.org/10.3969/j.issn.1000-3428.2007.23.011This paper presents a different MAC Protocol which is specially designed for narrow-bandwidth WLAN. Simulation result and numerical analysis are presented to demonstrate the effectiveness of dual_stage busytone backoff (DBBO). The simulation result also proves that the correctness of the numerical analysis.
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Computer Engineering. 2007, 33(23): 35-36,3. https://doi.org/10.3969/j.issn.1000-3428.2007.23.012Outlier detection is an integral part of data mining, and the density-based method LOF is the current state of the art in outlier detection. However, LOF is very sensitive to its parameter k and MinPts, which may result in wrong estimation. This paper proposes a new outlier detection algorithm based on Voronoi diagram called VOD. VOD measures the outlier factor automatically by Voronoi neighborhoods without parameter, which provides highly-accurate outlier detection and reduces the time complexity from O(N2) to O(NlogN).
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Computer Engineering. 2007, 33(23): 37-39. https://doi.org/10.3969/j.issn.1000-3428.2007.23.013This paper proposes that mobile agents act as carriers of tasks on behalf of users’ applications, accessing grid services intelligently in the dynamic complex service gird environment. The“most benefit traveling salesman problem (MBTSP)” is introduced to describe how agents act and a routing algorithm is also presented. Mobile agents are able to maximize the users’ benefits as well as assure different QoS requirements.
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Computer Engineering. 2007, 33(23): 40-42. https://doi.org/10.3969/j.issn.1000-3428.2007.23.014This paper proposes an opportunity dynamic assign algorithm that based on performance prediction scheduler, connecting weights, and dynamic load balance system, which utilizes the dispatcher. It includes severs sub system such as dispatcher, interactive session support unit, etc. Experimental results show that the proposed algorithm can quickly and exactly find out the best server that deals with request and improve the performance on load balance. Thus it makes preparation for further service.
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Computer Engineering. 2007, 33(23): 43-44,5. https://doi.org/10.3969/j.issn.1000-3428.2007.23.015A critical issue for complex software architecture design is modeling and analysis of dynamic architecture. This paper argues for an approach to specification of potentially unbounded dynamic structure based on Wright, an architecture description language. To support recursion mechanisms in software architecture specification, it identifies the concepts of composite connector and dynamic role, and illustrates how it can be used to create dynamic extension of structure. It provides mechanisms for designing dynamic architecture in an incremental way, and is available for architectural connectors reuse.
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Computer Engineering. 2007, 33(23): 45-47,5. https://doi.org/10.3969/j.issn.1000-3428.2007.23.016By abstractly analyzing the characteristic of syntax and semantics of modeling languages, a model mapping approach based on semantic consistency is proposed. To use this approach, abstract target semantic model should be constructed firstly. Then, based on the idea of elements in source semantic domain being reconstructed in the target semantic domain, mapping relations from source model to target model are made via abstract target semantic model. This approach may not only to be a theoretical guidance for model transformation, but also can be a measurement for validating the mapping rules between models at different abstract levels. JavaServer Faces assisted with Enterprise JavaBeans is used as a target platform to help interpreting the process of using this approach.
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Computer Engineering. 2007, 33(23): 48-50. https://doi.org/10.3969/j.issn.1000-3428.2007.23.017Simulating biological immune mechanism to implement performance rejuvenation is a new research approach for computing grid. This paper analyzes and compares the immune process’ characteristics and computing system’s rejuvenation, sets up the logical model of system rejuvenation based on immune Agent, and constructs a mathematics model for performance degradation, then puts forward a method to make decision for rejuvenation policy. On the basis of which, an application regarding audio-video resource transaction process system as background is studied, a two-stage hyper-exponential model is proposed to evaluate system performance. The results of case study indicate that this method is effective and feasible.
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Computer Engineering. 2007, 33(23): 51-53. https://doi.org/10.3969/j.issn.1000-3428.2007.23.018Attribute reduction that has been proved to be a NP-hard problem is one of the important issues of the KDD based on the rough set theory. A novel attribute reduction algorithm of rough set based on the vertebrate immune mechanism is proposed. The main operators of the algorithm include memory cells producing, clone selection, hyper-mutation and population updating. The key of its design is to integrate discernible ability and the elements in the condition attribute set into one unified affinity maturation objection. The different attribute reduction sets that can maintain the ability of classification can be found through maintaining the diversity of antibody population with renewal of antibody and similar antibodies suppression. The experimental results show that it is effective.
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Computer Engineering. 2007, 33(23): 54-56. https://doi.org/10.3969/j.issn.1000-3428.2007.23.019Visual simulation(VS) is the key technique of simulation applications, such as aim simulation. Currently, many VS applications are developed upon 3D graphical platforms directly (e.g., OpenGL, Vega). However, most of these platforms don’t consider domain modeling as the first class abstraction. Applications developed in this manner are very unlikely to be adaptive to changes of requirements. Therefore, a new VS framework, IncrEx, is designed. By inserting a simulation object layer, 3D behaviors could be encapsulated in both graphics and simulation oriented manner. In addition, these behaviors could be shared among different simulation objects so that simulation objects could be implemented in an iterated process based on code reuse.
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Computer Engineering. 2007, 33(23): 57-59,6. https://doi.org/10.3969/j.issn.1000-3428.2007.23.020The massive values computation module needs exhaustion tests in the software test. Insufficiency and limitation exist in traditional software test method. This paper produces test data by using interval algorithm and comparison is presented between interval algorithm test method and the traditional software test method. Conclusion indicates the interval algorithm can solve the problem that the traditional one can not, such as finding possible computation exception of program and judging whether it can present the upper limit scope of output variable or whether it has any branch hard to achieve.
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Computer Engineering. 2007, 33(23): 60-62. https://doi.org/10.3969/j.issn.1000-3428.2007.23.021Based on goal-scenario coupling and conception attribute, this paper presents a structured method of goal description and identification, constructs goal model, describes and identifies goals. Integrated with the goal-driven software architecture modeling method smoothly, the method improves the development quality and production efficiency of information system. The experimental results shows the method is effective.
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Computer Engineering. 2007, 33(23): 63-64,9. https://doi.org/10.3969/j.issn.1000-3428.2007.23.022Pervasive computing integrates information space with physical space. In this incorporated space, users can obtain digital services non-intrusively anytime and anywhere. Meanwhile, the service brings forth security challenge. Aiming at the unpredictability of the cooperated principals, this paper classifies the present trust research, proposes trust management method of pervasive computing, and resolves two challenging problems.
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Computer Engineering. 2007, 33(23): 65-67. https://doi.org/10.3969/j.issn.1000-3428.2007.23.023The calculation of storage tank is the core of measurement management. It is important to implement the software mechanism for calculation algorithm. This paper puts forward the strategy based on COM+ technology. Data are optimized by the method based on Hash table. The scheme of software deployment on three-tier structure is put forward, which makes up for defects of the previous software, such as bad real-time and reusability. Pratices show the caculation software is effective.
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Computer Engineering. 2007, 33(23): 68-70,7. https://doi.org/10.3969/j.issn.1000-3428.2007.23.024Currently, the approach of generating use case models mainly depends on the threads or relationships formed by method calls, which is limited for understanding the target system. This paper presents an approach of recovering use case models from dynamic information combining with static information. The approach generates basic use cases from method calls sequence, regulates the basic use cases according to relationship among classes and the static dependency graph, finds out the interaction point between user and the module to which the extracted use cases belong, and generates use case model with semantic information, which is more useful for the user to understand the target system.
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Computer Engineering. 2007, 33(23): 71-74. https://doi.org/10.3969/j.issn.1000-3428.2007.23.025Workflow is a series of business procedures that performs automatically. Workflow engine is important in entire management system, and offers execution environment. This paper designs a workflow description language——X-WPDL, implements workflow engine centering on peers, translates workflow described by X-WPDL into a series of “execution in order” related to processing operation, offers an interface between manager and participant, discusses design of X-WPDL, structure and operation of engine, and verifies the application of the engine.
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Computer Engineering. 2007, 33(23): 75-77. https://doi.org/10.3969/j.issn.1000-3428.2007.23.026Based on the mobile database management system——SwiftDB, this paper develops a swift business customizing tool——SwiftBMCT for customizing the enterprise management module. The tool utilizes the thought of software reuse, combines the template mechanism with the customizing principles, allows clients to customize modules to meet their demands, extends associative function to mobile terminal, and implements corporate information services based on location by trigger mechanism.
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Computer Engineering. 2007, 33(23): 78-80,8. https://doi.org/10.3969/j.issn.1000-3428.2007.23.027The recognition and creation of hot paths is one of the key factors in promoting the performance of a dynamic binary translator. To promote the accuracy of the hot path prediction, it is necessary to do a more thorough run-time profiling, which will lead to a rise in overhead. So a tradeoff between accuracy and overhead is needed. This paper studies the current profiling strategies and proposes an improved hot path recognition scheme.
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Computer Engineering. 2007, 33(23): 81-83. https://doi.org/10.3969/j.issn.1000-3428.2007.23.028Difference of node machine performance and dynamic operation environment are main reasons to cause the unequal division. This paper proposes index and method of difference scaling, combines master/worker computing model with SPMD application types, and gives three kinds of load balancing algorithm. The application shows the algorithms is effective.
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Computer Engineering. 2007, 33(23): 84-86. https://doi.org/10.3969/j.issn.1000-3428.2007.23.029This paper presents the design and implementation of the co-array Fortran(CAF)compiler based on GNU Fortran compiler. The CAF compiler translates CAF into Fortran 90 plus calls to runtime library. Typical tests are performed and the results show that CAF has better scalability. CAF gains better performance than OpenMP due to the explicit control on shared data distribution.
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Computer Engineering. 2007, 33(23): 87-89. https://doi.org/10.3969/j.issn.1000-3428.2007.23.030
The problem region of software code walkthrough is analyzed, and the basic functions of software walkthrough assistant tool are offered. By applying model driven architecture method, according to the features of the tool, this paper builds the platform independent model, platform specific model and the code model step by step. Initial transition principles among different models are studied. The non-automatic transitions among models of the tool are reached.
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Computer Engineering. 2007, 33(23): 90-93. https://doi.org/10.3969/j.issn.1000-3428.2007.23.031Due to the demand of integration of heterogeneous data sources, a semantic-based data integration system with three layers is designed, in which a middle layer between user layer and data layer is added to hide heterogeneity of various data sources. In practice, this paper introduces the ontology used as a common semantic description, and establishes the mapping between the ontology and heterogeneous data sources, and applies Web ontology language(OWL) to describe the ontology and the mapping. A heterogeneous data integration system, which can translate ontology-based global query into data-sources-based local query, is designed and realized to resolve the problem of semantic heterogeneity. Key technologies are discussed.
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Computer Engineering. 2007, 33(23): 94-96. https://doi.org/10.3969/j.issn.1000-3428.2007.23.032This paper proposes a model of Chinese full-text retrieval system based on Lucene which is an open source full-text retrieval engine, and expatiates its frame. This model is composed of seven modules, among which the index module and the search module are the core parts. It designs them concretely, and improves the search efficiency of the full-text retrieval system with index technology and search technology. The system model concludes an encryption module to encrypt the index and increases the system security.
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Computer Engineering. 2007, 33(23): 97-99. https://doi.org/10.3969/j.issn.1000-3428.2007.23.033This paper introduces the properties and mechanisms of three kinds of software(NS2, OPNET and GLOMOSIM). All the software is operated based on simulation scripts, but it is difficult to develop the scripts for the simulation, when the size of the simulation network is very large and the network objects are very complicated. NS2 is taken as an example to analyze the difficulties in script programming and a script programming method based on C++ is proposed, which can effectively improve the efficiency and correctness of the script programming. Experimental results demonstrate the effectiveness and efficiency of the methods. Because the scripts for different network simulation tools are considerably similar to each other, the method can be widely adopted in different network simulation tasks.
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Computer Engineering. 2007, 33(23): 100-102. https://doi.org/10.3969/j.issn.1000-3428.2007.23.034Binary translation is the technique that translates binary program from one machine platform to another, which enables the binary code to migrate among heterogeneous machine platforms. This paper introduces the principles of binary translation, and focuses on the design and implementation of CrossBit dynamic binary translation infrastructure, including its system architecture and essential design philosophies. Experiment data are provided to prove binary translation’s performance advantage.
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Computer Engineering. 2007, 33(23): 102-104,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.035Network component is a new distributed software component model and a hotspot research. This paper studies the structure of the network component, which consists of physics domain, individual domain and whole domain. The formalized definitions of the components are given, and whose basic characteristics are analyzed. To satisfy these characteristics, the system architecture for network component based on Web service is put forward. An application of the architecture system is given, which is composed of the network components.
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Computer Engineering. 2007, 33(23): 105-107. https://doi.org/10.3969/j.issn.1000-3428.2007.23.036Good performance can be archived when fetching data from remote memory through high-speed network than that from local disk, and performance of network memory system can be improved by kinds of optimization. Based on a Linux network memory system(LNMS), a new prefetching algorithm——m-ppm is proposed to improve the performance in client part. The algorithm extends multi-Markov chains prefetching model to make it more suitable for LNMS. Other two common prefetching algorithms are implemented in LNMS for comparison. Experimental results show that m-ppm method is more effective, especially in multi-user mode.
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Computer Engineering. 2007, 33(23): 108-110,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.037The conventional network management technologies are mostly restricted within a single management domain. It is hard for management system in one domain to interact and share information with the counterparts in other domains, which restricts the development of many new management functionalities. The paper proposes a model of Internet management information search platform based on Web Service and P2P, which aims to provide a universal platform of information sharing and searching among different management systems. The model can effectively interconnect the isolated NMSs, integrate the heterogeneous information, maintain good performance, and achieve good scalability.
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Computer Engineering. 2007, 33(23): 111-113. https://doi.org/10.3969/j.issn.1000-3428.2007.23.038By extending current P2P file searching protocol, this paper proposes SP2PRep, a reputation management protocol suitable for super-peer networks. In SP2PRep, reputation votes of leaves nodes are centralized in supernodes. Only supernodes are responsible for processing reputation queries. Therefore reputation searching space becomes small. The running procedure of SP2PRep protocol is described as well as message format for implementation. Analysis and simulations show that compared with current reputation management protocols in P2P systems, SP2PRep protocol reduces the network cost and improves the efficiency of reputation searching and the average ratio of number of successful transactions to that of total transactions. The security of reputation votes in SP2PRep is equal to that of current protocol in peer-to-peer systems.
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Computer Engineering. 2007, 33(23): 114-116,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.039The finite energy is one of the importent features of wireless sensor network. The hiberarchy topology devides the whole network into many clusters, and chooses the cluster-heads for the route, which saves the energy of the nodes and prolongs the lifetime of the whole network. This paper presents a new hiberarchy topology arithmetic with birthday paradox theory based on the existing hiberarchy topology arithmetic, aiming at their shortcoming. This arithmetic distributes reasonably the time slots of every node among the different status, ensuring all the nodes in the network do the clustering and choose cluster-heads with least energy consumption, and prolongs survival period of the network effectively.
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Computer Engineering. 2007, 33(23): 117-119,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.040Based on analysis of information integration in telecom management (TM), concept of TM meta-model and data-model is proposed by introducing meta object facility (MOF). Metadata classes and meta-relationships in meta-model are defined by abstracting TM data. Core data classes in data model are defined from various dimensions to realize perfect information definition. Data model of actual system is established to validate the validity of the modeling.
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Computer Engineering. 2007, 33(23): 120-122. https://doi.org/10.3969/j.issn.1000-3428.2007.23.041Service discovery and resource location are prerequisites to information share and processing in mobile environment where service description and matching are the key issues which become more complex due to diversity and heterogeneity of services, as well as volatility of mobile environment. This paper presents a service description model for various and heterogeneous services, designs implements the efficient storage and service query for this model which includes accurate matching and partial matching. Experimental results show the service matching exceeds XPath for XML-fashion services in query performance.
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Computer Engineering. 2007, 33(23): 123-125. https://doi.org/10.3969/j.issn.1000-3428.2007.23.042This paper proposes a robust reputation mechanism which eliminates misjudged reputation value caused by the node’s collusion behavior. It also considers the history factor when calculating the reputation value, and brings it in multicast routing for ad hoc networks. A new probabilistic multicast routing algorithm RBPMRP based on the new reputation mechanism is proposed. The simulation shows the new algorithm performs better than ODMRP especially when selfish nodes increase.
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Computer Engineering. 2007, 33(23): 126-128. https://doi.org/10.3969/j.issn.1000-3428.2007.23.043In order to deal with the distributed data consistency problem, an efficient distributed consensus is given in bus networks. Through “Mod” computing, the algorithm changes distributed decisions into single-computer decisions to improve the efficiency and to decrease the message numbers. And it decreases the message kinds and the response delays by message multiplexing. Performance analysis and simulation results show the algorithm has less time complexity O(1) and message complexity (T+E)×|Cset|+2×T, where Cset is a co-current set, T is the average delay of point-to-point communication, and E is the average delay of a critical section executing.
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Computer Engineering. 2007, 33(23): 129-131. https://doi.org/10.3969/j.issn.1000-3428.2007.23.044A new negotiation model named multi-agent negotiation model with service-oriented architecture, which combines the characteristics of service-oriented architecture and multi-agent negotiation system, is introduced concisely. The multi-agent negotiation service part which is a part of the new negotiation model is designed and implemented, and the process of the inference engine in a negotiation agent is discussed. The negotiation service part with SOA and the negotiation agent management platform are combined together to setup the application environment of the software. It supports the negotiation in an open environment to realize the application of the multi-agent negotiation model with SOA in e-business.
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Computer Engineering. 2007, 33(23): 132-134. https://doi.org/10.3969/j.issn.1000-3428.2007.23.045Live media streaming, which is interruption sensitive, is an important aspect of application layer multicast. It is important to restore the spanning tree when a node leaves. This paper analyses several familiar schemes to solve this problem, and proposes a bandwidth considered proactive route maintenance method. In this method, every non-leaf node computes backup route for its children nodes before it leaves. So children nodes can quickly switch to backup route when their current parent node leaves. In order to improve the stability of the spanning tree, it selects the node having the max service capability as backup route.
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Computer Engineering. 2007, 33(23): 135-137. https://doi.org/10.3969/j.issn.1000-3428.2007.23.046With the development of Internet, edge broadband access device is becoming one of bottlenecks restricting network applications. How to forward packets more quickly and provide better quality of service in edge network is very important for end-to-end QoS. This paper introduces the flow switching technology, describes the processing of IPv6 packet flow, and analyzes the QoS features of IPv6. It proposes a frame structure of edge broadband access router based on IPv6 flow-aware and defines the relevant functions of components in router. An intelligent packet discard policy is discussed.
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Computer Engineering. 2007, 33(23): 138-139,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.047Based on the analysis of dynamic host configuration protocol(DHCP) protocol, aiming at the disadvantage of the DHCP protocol, which is the fact that the DHCP server can not get the IP address of non-DHCP clients and twice or more DHCP processes are caused, a new solution is put forward to solve this problem. The solution lowers the probability of the phenomenon of network congestion and improves the whole performance of the network.
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Computer Engineering. 2007, 33(23): 140-141. https://doi.org/10.3969/j.issn.1000-3428.2007.23.048As distributed system is affected by high time delay and low bandwidth of Ethernet, a StarFabric of the high-speed performance is designed for the protocol of fabric layer. The program interface of the protocol is completed in VxWorks operating system. Test results show that time delay is much lower while bandwidth far bigger than Ethernet, which proves the success of the protocol.
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Computer Engineering. 2007, 33(23): 142-144. https://doi.org/10.3969/j.issn.1000-3428.2007.23.049Network address translators (NAT) can resolve the problem of globally unique IP address deficiency. But NAT causes difficulties for peer-to-peer (P2P) communication, since it drops any unsolicited incoming message. This paper analyzes the prevail solution that enables a connection between hosts located behind NATs based on UDP protocol , and provides a better solution based on proxies .
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Computer Engineering. 2007, 33(23): 145-147. https://doi.org/10.3969/j.issn.1000-3428.2007.23.050Since NGN became the future of PSTN and VoIP, soft-switch, as an essential part of NGN, has been more and more popular. The suppliers need a good soft-switch operation management platform, which is good at expansibility as well as compatibility. This paper shows the framework of an operation management platform. The platform, based on the open source Asterisk system architecture, has characteristics of some typical soft-switch operation, and realizes various kinds of new operation. Improvement to the management and the extensibility of operation is made.
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Computer Engineering. 2007, 33(23): 148-150,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.051
Block cipher cryptosystems embedded in cryptographic devices are sensitive to a series of cryptanalysis such as power analysis. The Walsh spectrum is an important basis for studying the Boolean functions in block cipher. This paper proposes a new method based on Walsh spectrum to reveal the key embedded in cryptographic. Furthermore, conclusion are drawn and proved that the vulnerability against power analysis caused by the highly nonlinear S-boxes. Experimental results indicate that the new method speeds up the revelation of key and yields higher precision.
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Computer Engineering. 2007, 33(23): 151-153. https://doi.org/10.3969/j.issn.1000-3428.2007.23.052An access control scheme for synchro-coroutine, an algorithm to calculating public authorities and an automatic coding method are proposed to resolve the problems resulted from information sharing using synchro-coroutine among cooperant members, including illegitimate access, efficiency problem and the problem of how to control dynamic created information. The application result shows that the access control scheme can reduce the communications traffic to 50 percent and the algorithm is feasible.
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Computer Engineering. 2007, 33(23): 154-155,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.053
This paper presents a composite spatial-temporal approach to image encryption. In the temporal domain, chaotic series acts as a key for the AES encryption. It generates and administers its key without compromising any of its nice features. In the spatial domain, the paper presents a new way of deriving a space transform matrix by chaotic series. The chaos series is generated by the logistic equation, whose parameters are modulated. Therefore, short cycles are avoided in the solution sequence of the chaotic system. Experimental results confirm the effectiveness of the proposed method. Also, there is no damage to the decrypted image.
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Computer Engineering. 2007, 33(23): 156-157. https://doi.org/10.3969/j.issn.1000-3428.2007.23.054All the existed authenticated encryption schemes either have only considered the process of authenticated signature without using Hash functions and redundancy functions or have only discussed the signature’s convertibility. So it proposes a new convertible authenticated encryption scheme without using Hash functions and redundancy functions which are based on ECC. The convert of signature in this scheme can be executed without signer. The scheme’s security is analysed.
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Computer Engineering. 2007, 33(23): 158-160. https://doi.org/10.3969/j.issn.1000-3428.2007.23.055In some special applications, such as electronic voting schemes, the schemes can distinguish whether two or more different signatures are generated by the same signer or not. Linkable ring signature can realize the function. Previous linkable threshold ring signature schemes are constructed on the base of DL-based public key system. This paper proposes a separable linkable threshold ring signature scheme on the difficulty of DL problem and factoring, which allows the use of both DL-based and ID-based public keys at the same time. And the participants can choose public key system, system parameters and keys independently of each other. So it is more practical.
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Computer Engineering. 2007, 33(23): 161-162,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.056This paper presents a new verifiable threshold blind signature scheme based on the elliptic curve by adopting threshold cryptography and blind signature scheme. This scheme has several security characteristics, such as blindness, robustness and non-forgery etc. It is able to prevent adversaries from getting the secrets or sub secrets and efficiently guard against cheating among participants. It analyzes the security and efficiency of this scheme, which is compared with the scheme of Zheng Zhuo.
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Computer Engineering. 2007, 33(23): 163-166. https://doi.org/10.3969/j.issn.1000-3428.2007.23.057This paper presents a new logic which can be used to analyze security protocols. There is no necessity to idealize protocols when analyzing authentication protocols, which can avoid analysis errors caused by informal idealization. The new logic can be used to analyze accountability and fairness in electronic commerce protocols including the real-world protocols. The process of analyzing protocols is concise and can be implemented automatically.
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Computer Engineering. 2007, 33(23): 167-169. https://doi.org/10.3969/j.issn.1000-3428.2007.23.058Defending distributed denial of service(DDoS) attacks is one of the most difficult security problems in Internet. A novel intrusion detection system based on data mining to detect DDoS attacks in real time is presented. K-means cluster algorithm combining Apriori association algorithm is used to group the quantitative attributes in network traffic, and extracts traffic patterns from network data to generate detection models. Experimental result shows that DDoS attacks can be detected efficiently.
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Computer Engineering. 2007, 33(23): 170-172. https://doi.org/10.3969/j.issn.1000-3428.2007.23.059This paper proposes a new online signature verification algorithm based on the comparison and analysis of online signature verification algorithm. This algorithm is used to compute point coordinate(x, y) in pattern so that extreme point is acquired when derivatives of x and y are. Extreme is used as segmenting boundaries and a set of rules derived from the properties of extreme are defined. Regional features in signature are extracted and expanded fully. The experiments show that the false rejection rate and false acceptance rate are decreased obviously.
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Computer Engineering. 2007, 33(23): 173-175. https://doi.org/10.3969/j.issn.1000-3428.2007.23.060By adding the management factor, the network security adapted key models of PDR and P2DR are extended to P2DRM model to implement dynamic network security management. Also, correlation algorithm and agent technology are integrated into P2DRM, and monitor on attach and response of distributed network are implemented through sub-systems. This model can be used in network security monitor system to make network security management efficient and to meet network security dynamic monitor requirement.
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Computer Engineering. 2007, 33(23): 176-178. https://doi.org/10.3969/j.issn.1000-3428.2007.23.061The main solution to multicast security is group key management, which includes real time key management and batch key management. This paper mainly discusses the group key distribution in real time group rekeying management, analyzes emphatically the realization of the multicast protocol, especially the PIM-DM protocol, directs at the PIM-DM protocol, and develops a model of real time group rekeying management. The author makes use of multicast protocol in software NS to conduct simulation study on key management of centralized mechanism and decentralized mechanism. As a result, the security of this protocol is enhanced.
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Computer Engineering. 2007, 33(23): 179-181. https://doi.org/10.3969/j.issn.1000-3428.2007.23.062CA system security is the key problem to influence the security in E-commerce. This paper analyzes the network architecture of CA system, and presents a multi-layer and multi-aspect security architecture of CA system. The security design focuses on the network layer and application layer. Firewalls divide CA system network into different security grade areas. The following methods are employed in the application layer for security protects: add the digital signature at the end of the software to prevent invalid code modify, add the sender time stamp in the packets to prevent repeat packets attack, clear to zero in memory and save the important data as encrypted in the database to prevent invalid reading, use central monitor system. The design is employed in a real CA system successfully.
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Computer Engineering. 2007, 33(23): 182-184,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.063Add an inter-operated behavior module that can fulfill the communication among fishes and interact with environments to cognition-based behavior model of artificial fish, in order to build up architecture and model of artificial fish oriented schooling behaviors. A method which studies the school of artificial fish based on multi-agent system is given. Each artificial fish in school based on that kind of architecture is modeled as an agent, which can perceive information from the virtual environment, generate appropriate intentions, manage rational behaviors, and create motion to realize the intention. Through building up the model of locomotion, pursuit and evasion of agent in school, self-organized behaviors of school can be emerged by the interaction among individuals, so as to realize vivid simulations of artificial fish schooling.
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Computer Engineering. 2007, 33(23): 185-188. https://doi.org/10.3969/j.issn.1000-3428.2007.23.064Because of user’s various inquires, a new algorithm, named rough set clustering-based dynamic materialized view algorithm(RSCDMV) is presented. Based on rough set clustering on materialized view, the algorithm can execute dynamic adjustment which both satisfies the variety of the queries and take the hierarchy of dimension into consideration. Experimental results show, as the queries set increase, RSCDMV will show more advantages as inquires change.
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Computer Engineering. 2007, 33(23): 189-190,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.065This paper introduces quantum potential, distribution mechanism of particle, a quantum clustering algorithm, gives the physical essence of the quantum clustering algorithm, and points out its advantage and the shortcoming. Based on the above, an improved algorithm distance-based quantum clustering(DQC) is produced. The cluster accuracy ratio of DQC about the IRIS dataset outperforms that of QC 8%. Experimental results demonstrate its higher efficiency and better performance.
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Computer Engineering. 2007, 33(23): 191-193. https://doi.org/10.3969/j.issn.1000-3428.2007.23.066The automatic detection method adopting computer vision principle and artificial neural network technology is a new development in computer detection. It has lots of advantages such as no touch with inspected objects, high speed, high efficiency and good flexibility etc. So it has extensive applied foreground in the modern detection of product quality. This paper introduces the general structure of the product quality detection system based on neural network and computer vision, expounds the realization method of an example of this kind of system, namely the on-line crack detection system of glass bottles. The system’s ability to learn itself and adapt itself is very powerful due to the application of neural network. It has realized a quick and exact detection of on-line glass bottles’ crack successfully.
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Computer Engineering. 2007, 33(23): 194-196. https://doi.org/10.3969/j.issn.1000-3428.2007.23.067This paper discusses measure of harmony between clustering and transcendent knowledge, and a new clustering algorithm is proposed, which is parallel artificial immune clustering algorithm based on dynamic granulation. Artificial immune system model has the characteristics, such as parallel, random search, and maintains diversity. It is unified to dynamic granulation model. In the process of granulation changing, appropriate granulation can be made by adjusting, which can ensure clustering efficiency and quality of the new algorithm. Test results show that the algorithm is reasonable when the problem is handled, which has many samples, many attributions and many classifications.
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Computer Engineering. 2007, 33(23): 197-198,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.068Affinity propagation clustering is an efficient and fast clustering algorithm, especially for large data sets, but its clustering quality is low when it is applied to a data set with loose cluster structures. This paper proposes semi-supervised affinity propagation, where cluster validity indices are embedded into iteration process of the algorithm to supervise and guide its running to an optimal clustering solution. The experimental results show that the algorithm gives accurate clustering results for data sets with compact and loose cluster structures.
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Computer Engineering. 2007, 33(23): 199-201. https://doi.org/10.3969/j.issn.1000-3428.2007.23.069To overcome the limitation of precocity and stagnation in classical ant colony algorithm, this paper presents a multi-ant colony virtual parallel optimization algorithm. The ant colony is divided into several children ant colonies, and the pheromone flatness system is used in each child ant colony. By designing an immigrant operator, the parallel and cooperating optimization of children ant colonies ate obtained. Contrastive experiments show that the algorithm has a better capability of global optimization than traditional ant colony algorithm.
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Computer Engineering. 2007, 33(23): 202-204,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.070An available method of converting standard drawings into reusable bridge design case is developed. With this method, data object of design knowledge, which integrates both geometric descriptions and non-geometric description, is established with object-oriented technology. At the same time, bridge data are divided into several levels for better comprehensibility and lower programming complication. Design case is stored into database with SQL server 2005. Similarity definition of bridge case is carried out by analyzing bridge design knowledge in order to get relative similar design cases. Case intelligent adaptation technology is created by neural network for new bridge design, and so a bridge model, driven with knowledge and parameters, is achieved.
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Computer Engineering. 2007, 33(23): 205-207. https://doi.org/10.3969/j.issn.1000-3428.2007.23.071Information collection from Internet has become an important work for most information agencies of the world. This paper designs overall frame of Internet information collection and processing technology, proposes a search engine called IA(information assistant), which is knowledge-based and adopts some techniques of data mining, filtrates and classifies collected information. Being active, high-efficient, convenient, and flexible, the engine is benefit for information analysis.
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Computer Engineering. 2007, 33(23): 208-210. https://doi.org/10.3969/j.issn.1000-3428.2007.23.072In order to improve the real-time and anti-noise performance of the eye location method, this paper presents a coarse-to-fine eye location method (Gabor-pit-location, GPL) based on directly detecting “pit” feature in brow-and-eye region and the eye variance filter. With the direct extraction of “pit” topographic features, the candidate’s eyes are searched in brow-and-eye region extracted from the face image by use of Gabor wavelet transform. The prior knowledge of face structure and the eye variance filter are employed to determine the real eye positions in the face image. Comparative experiments are performed on the images with and without noise respectively, and the results show that GPL is better in the real-time, accuracy and anti-noise performance than the eye location method purely based on the terrain feature matching.
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Computer Engineering. 2007, 33(23): 211-212. https://doi.org/10.3969/j.issn.1000-3428.2007.23.073Gradient intensity and direction of current pixel is analyzed by the computation of horizontal and vertical gradient in Canny algorithm. Some mistakes may be made in the complex region for the incomplete information provided by horizontal and vertical adjacent pixels. The Canny algorithm based on directional filter is implemented. The new algorithm is described with some examples and the comparison between the old and the new method proves the new algorithm has advantage in the ability to detect edges and keep edges. And the change of parameters has a slight effect on the new algorithm.
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Computer Engineering. 2007, 33(23): 213-214,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.074This paper proposes a new parameterless support vector machine classifier based on quadratic programming, which avoids some shortcomings such as the need for choosing regularized parameter in standard SVM. Its formulation is simple and easy to be realized. Some numerical results illustrate that the new SVM classifier is feasible and effective.
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Computer Engineering. 2007, 33(23): 215-217,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.075Virtual plant technique is significant to crop yield, land productivity evaluation, resources environment analysis, crop cultivation instruction, crop growth mechanism research and control over crop growth and its reaction to the environment. This paper takes the midrib of maize leaf as axis and joins plane texture image of maize leaf, expresses the midrib of maize leaf as B-splines, carries out space transform, and embeds the texture image into transformed midrib curve of maize leaf. The method can be applied to all coordinates of the apex of leaf, where curve fitting can be carried out directly without leaf angle circumgyration, which yields maize leaves as real as they are.
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Computer Engineering. 2007, 33(23): 218-219,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.076This paper describes basic design object, main data and basic functions of 3D digital basin model system, which are designed under GIS and OpenGL environment, and presents some 3D structural result pictures obtained through the system. The system provides a direct analyzing and distinguishing measure to research the basin structure and oil & gas. Analysts can excavate the hidden information of the structure and oil, and estimate the consistency and rationality of the known model data according to the data superposition from the different origin in 3D space.
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Computer Engineering. 2007, 33(23): 220-222. https://doi.org/10.3969/j.issn.1000-3428.2007.23.077By studying the spatial-temporal correlation and the center-biased characteristics of motion vectors in image sequences, this paper improves traditional diamond search(DS) algorithm, designs an adaptive large diamond search pattern (ALDSP), and presents an adaptive diamond search motion estimation algorithm based on motion classification information of blocks. ALDSP adaptively chooses different search methods with motion classification information of blocks. For fast moved block, it predicts initial search point and uses different search methods according to blocks of different relative motion. Experiments prove that the algorithm can improve the search speed in contrast to motion vector field adaptive search technology(MVFAST), when video quality is better.
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Computer Engineering. 2007, 33(23): 223-225. https://doi.org/10.3969/j.issn.1000-3428.2007.23.078
This paper introduces HSV color space and an algorithm of automatic recognition character color. By using background subtraction technique and color analysis methods, the positions of characters are found, and characters are segmented with projection algorithm. BP neural network is applied in characters recognition to identify the number 0 to 9. Experimental results show that the proposed scheme is feasible and has great robustness.
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Computer Engineering. 2007, 33(23): 226-227,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.079Open test simulation platform directing at unit under test(UUT) is designed and realized. The platform can be used in testing of test program set(TPS) in auto test system(ATS) design. By using physical simulation method to realize UUT signal output and measurement in diverse working conditions, the platform can realize TPS integration and test, and validates the satisfaction of ATS function and targets without UUT.
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Computer Engineering. 2007, 33(23): 228-229,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.080This paper designs a low-power-consumption architecture of 2-D discrete wavelet transform (DWT) for image compression in the wireless sensor network. The architecture implements reduced complexity algorithm of DWT-(5, 3) integer DWT. It adopts pipeline and delay-line design technology to get high computation throughput and make data used by processing unit efficiently, reducing the number of on-chip and off-chip memory access. Multi-level DWT is implemented by unwinding, which makes the next level transforming start as early as it can without large in-chip memory and access operations. Simulation and FPGA implementation show the system satisfies the required performance, and it has the merits such as low complexity, low power consumption, small in-chip memory etc.
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Computer Engineering. 2007, 33(23): 230-232,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.081It is the uptrend to design large-scale real-time processing system by high performance digital signal processor (DSP) and parallel process technology. The multiple-DSP parallel process technology is discussed and the structure of multiple-DSP system based on network exchange architecture and the interlink technology among DSPs are studied. The debug and development solution of multiple-DSP system are presented. The technology extends the network connectivity capacity to combine DSP and network technologies perfectly, and boosts the development of networked measurement and control technologies.
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Computer Engineering. 2007, 33(23): 233-236. https://doi.org/10.3969/j.issn.1000-3428.2007.23.082To satisfy the similar but individual information requirement of SMEs in industry cluster district, a new development mode of ASP platform is proposed. How to decide the type and content of service is argued and corresponding rules is listed. The idea of customization in mass customization product is imported to implement service customization, which can satisfy the individual information requirement of SMEs. A new and configurable ASP Platform is designed and its design method, development mode and key technology are studied, involving its running mode, service cost and service price. A special town-faced ASP platform which provides the collaborative service mainly is demonstrated to illuminate the application way.
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Computer Engineering. 2007, 33(23): 237-239. https://doi.org/10.3969/j.issn.1000-3428.2007.23.083To meet the high quality for clock synchronization in EPA network system, a two-dimension fuzzy controller is constructed to demonstrate the quality of every device. The optimal master clock of the system is selected quickly and exactly from multi-field devices based on equitable competition. Based on the algorithm, the stability of EPA system is improved and the fluctuation of local clock is reduced. The accuracy of field devices’ clock synchronization is up to 50μs.
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Computer Engineering. 2007, 33(23): 240-242. https://doi.org/10.3969/j.issn.1000-3428.2007.23.084To provide client with fast, stable and credible services, the access network of ACR must have a set of reasonable access control mechanism. This paper adopts a fictitious process to carry out contrast studies on three kinds access authentication technology, and according to ACR system requirement, select the most suitable access authentication technology. Design of the task process for 802.1x technologies-based access control mechanism is given.
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Computer Engineering. 2007, 33(23): 243-245,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.085This paper presents a design of transparent bridge which can connect cable network and Ethernet in HFC network. The bridge is designed based on DOCSIS and supports MAC address learning, MAC frame filter and forwarding on MAC layer. The spanning tree protocol is employed in order to deactivate redundant network connections logically and reduce the topological loops to a tree topology consequently solve the problems of data feedback which result from the topological loops in HFC. The design has been successfully applied to the bidirectional system platform for HDTV, which consists of PHY chip and MAC chip developed in the authors’ lab. The design can effectually deactivate network redundancy and prevent the generation of broadcast storm.
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Computer Engineering. 2007, 33(23): 246-248. https://doi.org/10.3969/j.issn.1000-3428.2007.23.086Based on location technology of GPS/GSM network, the parameters about the user’s movement locus, real speed, locomotion direction and vehicle state of mobile aim are mornitored and controlled, in order to ensure safety of mobile vehicle, schedule management and operation efficiency. The system is composed of mobile vehicle, transfer network and monitor center, where data are transmitted based on GSM sound channels, and exchanged between GPS block and AT89C51 based on RS232 serial communication ports. The paper introduces hardware composition, work principle and software design of mobile vehicle location system. Relative technologies of mobile location are discussed.
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Computer Engineering. 2007, 33(23): 249-251. https://doi.org/10.3969/j.issn.1000-3428.2007.23.087Cache is one of the most popular methods to solve the problem of the speed difference between CPU and memory in muti processors system. Because data are shared by multiprocessors, how to keep data coherence between Caches is a key problem. This paper presents the design of Cache architecture of a 32-bit RISC microprocessor chip “LongTeng R2”, and discusses the coherence protocol. And the result of design is given.
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Computer Engineering. 2007, 33(23): 252-254,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.088Two new structural models of ROM and RAM for testing are given, which can be used as testing primitives in the digital automatic test pattern generation(ATPG) systems. Test patterns for circuits with ROM chips are generated automatically after ROM’s converting to a combinational model, while the ATPG problems for circuits with RAM chips are also resolved after RAM is equivalent to a sequential model.
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Computer Engineering. 2007, 33(23): 255-257,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.089The interrupt processing is the core of embedded real-time operating system. The module structure and device management pattern on Windows CE.net are discussed. A deep-going analysis is given to the interrupt architecture on Windows CE.net. The whole process and realization code about interrupt processing with ISR and IST are analyzed on this base. This paper provides a general method of Windows CE.net interrupt processing.
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Computer Engineering. 2007, 33(23): 258-260. https://doi.org/10.3969/j.issn.1000-3428.2007.23.090According to the requirement of the management of iSCSI storage system, this paper designs a SNMP/Web based graphical unified management platform with the implementation of storage network topo-discovery, storage data management and storage resource management(SRMP) through research of simple network management protocol(SNMP) and Web based management system(WBMS). The system has a good extensibility and architectural independence.
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Computer Engineering. 2007, 33(23): 261-263,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.091This paper discusses the B-spline surfaces smooth joining technique. The definition of parameter surface geometric continuous condition is discussed. Based on above definition, two algorithms of G1 smoothly joining of B-spline surfaces are proposed. One adjusts control vertexes of common border curve, and the other adjusts control vertexes near the common border curve of one of these surfaces. The result shows that using this method flexibly can effectively resolve the relative problems in surface modeling.
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Computer Engineering. 2007, 33(23): 264-266. https://doi.org/10.3969/j.issn.1000-3428.2007.23.092This paper discusses problems of multiple instruction multiple data image parallel-processing architecture, presents an image parallel processing system with flexible structure, which is named flexible structure image parallel processing system. Differences in structure and performance between flexible structure image parallel processing system and typical image parallel processing system are analyzed. An actualization scheme of flexible structure image parallel processing system based on TI C6000 serials DSP is given. Analysis and experiments result shows that flexible structure image parallel processing system has strong adaptive faculty and is easy to be adjusted, extended or updated.
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Computer Engineering. 2007, 33(23): 267-269,. https://doi.org/10.3969/j.issn.1000-3428.2007.23.093Integration application software platform is a core component during construction of digital campus. A software architecture based on Web services for digital campus’s integration application software platform is introduced in this paper, then fundamental theory, key factors and creativities to design of three key technologies for the digital campus’s integration application software platform(campus information portal, PKI/CA, and data integrity)are emphasized. Practice shows that the digital campus’s integration application software platform based on above software architecture and the key technologies runs securely, reliably, and gains several universities’ praises during its operation.
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Computer Engineering. 2007, 33(23): 270-272. https://doi.org/10.3969/j.issn.1000-3428.2007.23.094The paper introduces the basic concept of WLAN, and on the base of analyzing the theory of security policy, discusses the security problem of WLAN. A design of security system that is based on embedded flat is proposed, which combines encryption algorithm with higher security and advance verification policy. It is of some value in solving the security problem in WLAN.
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Computer Engineering. 2007, 33(23): 273-275. https://doi.org/10.3969/j.issn.1000-3428.2007.23.095Based on the analysis of the actuality of inspection data management for the enterprise, this paper puts forward and establishes the system architecture of product inspection management system. System processes and key technologies are also introduced. The use of administrative levels and structured model framework facilitates the realization of data import, edit, statistical analysis, report output and other functions. This system supplies the necessary data for other information systems in this enterprise. After the implementation of the system, the enterprise achieves the electronic inspecting procedures and enhances the inspection efficiency.
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Computer Engineering. 2007, 33(23): 276-278. https://doi.org/10.3969/j.issn.1000-3428.2007.23.096According to features and demands of the social security industry, this paper presents a C/S/S structural social security system model based on J2EE. In system design process, designers introduce the ideas of component, workflow; use several J2EE design patterns such as Business Delegate, Session Façade, and construct the enterprise framework for normalizing system hiberarchy and building system services. The system applies an optimization strategy for solving bottleneck of EJB calls and provides security service, log service.
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Computer Engineering. 2007, 33(23): 279-280. https://doi.org/10.3969/j.issn.1000-3428.2007.23.097The effective processing of experimental data is one of the common problems in scientific research. The paper presents an approach to automatic data processing in the test of enhancement algorithm for DICOM-based image. The test system realizes data exchange implement between Matlab and Excel by using DDE technique and makes full use of their advantages to realize the automatic data processing. The method is simple and practical. It shortens the research period and gives powerful support to algorithm improvement.
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Computer Engineering. 2007, 33(23): 281-283. https://doi.org/10.3969/j.issn.1000-3428.2007.23.098Computer users access data by file system. File and folder operation(such as creation, deletion, and edition) may leave some traces on storage media. These traces are related to file system. NTFS file system allocates and revokes the storage by cluster. It manages by MFT. This paper, from the point of computer forensics, analyzes the method of accessing file for NTFS file system and the traces of the file or folder operating, and compares it with traces of FAT.
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Computer Engineering. 2007, 33(23): 284-封3. https://doi.org/10.3969/j.issn.1000-3428.2007.23.099This paper describes the design and implementation of amobile robot control system based on embedded Linux. The four main modules, namely motion control and sense module, main control module, human-machine interface, and wireless communication module, are discussed. The whole system is easy to expand and port. The Zigbee protocol is integrated into the wireless communication module, which makes it possible to study the corporation between the mobile robot and wireless sensor network. The system is proved to be powerful enough to complete the complicated control of robot.
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