05 January 2007, Volume 33 Issue 01
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Computer Engineering. 2007, 33(01): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2007.01.001On the basis of the introduction of the LT Code, this paper explores the Raptor Code. Precoding method is the essential part in the Raptor Code and can overcome the deficiency that time and space overhead is not fixed in the LT Code. It puts forward improving method based on RS Code through the analysis of the multiple levels precoding method. The improving method has many advantages such as high decoding rate and provides appropriate solution to the problem of safe transmissions in the Internet.
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Computer Engineering. 2007, 33(01): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2007.01.002Active queue management (AQM) can maintain smaller queueing delay and higher throughput by the purposefully dropping the packets at the intermediate nodes. Several different AQM algorithms have been proposed. Almost all the existed algorithms neglect the impact on performance caused by large round-trip time (RTT). This paper proposes a new AQM mechanism based on Dahlin algorithm in control theory to restrict the negative impact on the queue stability caused by the large RTT. The simulation experimental results show that the integrated performance of the proposed algorithm is obviously superior to those of the existed schemes.
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Computer Engineering. 2007, 33(01): 7-9. https://doi.org/10.3969/j.issn.1000-3428.2007.01.003Based on research of the parallel of FIR filter algorithm and direct type FIR filter, and combined with architecture characteristic of LS CSIMD, one FIR filter mapping algorithm is proposed. The mapping algorithm partitions variable tap FIR filter into some sub-filter and middle results of sub-filters are stored local memories of corresponding to RPU. Adopting the mapping algorithm, as FIR filter tap N≤64, one result is generated per one clock cycle. As 64
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Computer Engineering. 2007, 33(01): 10-12. https://doi.org/10.3969/j.issn.1000-3428.2007.01.004Like human negotiation, agent negotiation needs to reach an agreement in advance about negotiation issue, procedure, scheme and etiquette, these ensure negotiation go on normally. An electronic negotiation protocol is designed, which includes four sub-protocol, they are sponsor, negotiation termination, parallel negotiation and identity authentication. It provides agent a group of rules for negotiation framework. This protocol conforms to the principles of security and fair property, and processes the properties of Pareto optimization, Nash balance and non-cheat.
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Computer Engineering. 2007, 33(01): 13-15. https://doi.org/10.3969/j.issn.1000-3428.2007.01.005This paper presents a generic model for the communication interface of IP cores in SoC design. To represent the interface model in a clear and readable format, this paper proposes an XML-based description medium named IDF-XML using XML technology, which takes its full advantages. Also, a transform mechanism is used to parse IDF-XML and generate object models for interface synthesis. As preliminary experiments, this model is applied to the DCT module of a simple digital camera design. An interface synthesis algorithm is used to generate interface modules between incompatible parts to facilitate smooth communication.
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Computer Engineering. 2007, 33(01): 16-18. https://doi.org/10.3969/j.issn.1000-3428.2007.01.006The numerical verification of geometry theorem proving makes use of numerical computation instead of symbolic computation to improve the efficiency, but there are still problems about the efficiency of complex propositions in practice. This paper attempts the parallel computation method to improve the efficiency, analyzes the partitioning, communication and the task-scheduling algorithm with the MPI programming model, realizes the parallel numerical verification algorithm with MPICH2, and tests the efficiency of algorithm through the parallel performance measure, then the results are satisfied.
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Computer Engineering. 2007, 33(01): 19-21. https://doi.org/10.3969/j.issn.1000-3428.2007.01.007This paper constructs a new group blind signature scheme on the basis of ACJT group signature scheme. The security of the new scheme is based on the strong RSA assumption and the decisional Diffie-Hellman assumption, of which is different from the scheme of LR98. In the mean time, the efficiency of the user to blind the content of the signer is improved. To blind the group signature of ACJT, this paper only adds the computation of modular exponentiation and modular addition; while the scheme in LR98 adds the computation of double discrete logarithm, root of the discrete logarithm and random permutation in order to blind the group signature of CS97. As a result, the scheme proposed by this paper is much lower than the one in LR98 with respect to computation complexity and higher with respect to efficiency.
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Computer Engineering. 2007, 33(01): 22-24. https://doi.org/10.3969/j.issn.1000-3428.2007.01.008One key problem in the cryptanalysis of GSM authentication algorithm COMP128 is identified and analyzed. After proving the NP-hardness of this problem, an approximate but practical solution is presented, which can improve the attack efficiency of the best attack software ever known.
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Computer Engineering. 2007, 33(01): 25-27. https://doi.org/10.3969/j.issn.1000-3428.2007.01.009The paper is concerned with the problem that the service entity only has the partial field of vision in the grid service, and causes the service to be restricted for application. A mechanism of the macro self-organization evolvement workflow based on the D-S evidence theory is proposed, which is based on the entity network interactive behavior, solves the entity confidence level measure, transmission and combination questions by the D-S evidence theory, and expands the control rule of the confidence level in the D-S evidence theory, proposes the proportion trust control rule. The experimental result shows that the workflow performance has been enhanced by the way.
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Computer Engineering. 2007, 33(01): 28-30. https://doi.org/10.3969/j.issn.1000-3428.2007.01.010ID model-IAIDM(Immune-based Adaptive Intrusion Detection Model) is put forward. Because current IDS usually has a problem of incomplete training sets, this page has done the deep researches on the problem caused by the limit of training time with the feature of IAIDM. Based on it, an incremental algorithm(IA) is put forward. The experiment results demonstrate IA can update local selfspace that has changed incrementally and dynamically instead of the whole space so that IAIDM can adjust itself to the current network environment quickly.
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Computer Engineering. 2007, 33(01): 31-33. https://doi.org/10.3969/j.issn.1000-3428.2007.01.011Notification service is increasingly being used in a wide variety of distributed computing systems. One problem with notification service is that it is sensitive to overload. By analyzing and simulating the performance of notification service, this paper reveals the relationship between maximum customers number permitted by notification service and utilizing rate of the system. Thus a fuzzy control mechanism of notification service performance is presented, to control and adjust maximum customers’ number of notification service system. Simulation experiment on mechanism is fulfilled. The outcome shows that fuzzy control can be accommodated to the change of notification service system load and system model more easily, and can control the load at random more efficiently than usual controller does.
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Computer Engineering. 2007, 33(01): 34-37. https://doi.org/10.3969/j.issn.1000-3428.2007.01.012This paper puts forward a kind of IP layer multicast congestion control algorithm based on hop to hop RED, proves its usefulness based on mathematics, and proves the STSR congestion control algorithm has a smaller congestion probability under the buffer area sharing than separating on the information frames transmit under the different priority policies, the STSR congestion control algorithm responding sensitively to network congestion and having larger networks throughput. It simulates the STSR model with NS-2, proving the STSR algorithm can ensure the TCP friendly and realizes the distributed control theory of coarser granularity. This conclusion has great realistic significance to the multicast congestion control research.
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Computer Engineering. 2007, 33(01): 38-39. https://doi.org/10.3969/j.issn.1000-3428.2007.01.013By using the secret sharing technique in the Schnorr signature scheme, a new scheme of fair exchange protocol is proposed, whose fairness and security depend on two or more trusted third authorities. According to the security and fairness analysis of this protocol, compared with the fair exchange protocols that fully depend on only one TTP, the proposed protocol is more secure and reliable.
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Computer Engineering. 2007, 33(01): 40-43. https://doi.org/10.3969/j.issn.1000-3428.2007.01.014Token bucket algorithm is applied to solve the problem that a large amount of bandwidth is occupied by the BT traffic. It is analyzed how the download rate and the number of users in the controlled network are changed after BT bandwidth control. The result shows that the data transmission rate between the peers in the network increases properly, the average download rate of the peers in the network decreases properly, and the average peer number of the network increases. The device with the function of BT bandwidth control is placed in a test network. The test result shows that the algorithm is effective and the analysis result is correct.
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Computer Engineering. 2007, 33(01): 44-46. https://doi.org/10.3969/j.issn.1000-3428.2007.01.015Data-intensive computing applications often require the efficient transfer of terabytes or even petabytes of data in wide-area, distributed computing environments. This paper adopts a new approach to implement the striped transfer of data on the basis of GridFTP by utilizing multiple replica sources concurrently. MFTP, a FTP client implementation of the presented approach is addressed. Experiments show that MFTP improves the data transfer rate and reliability on grids.
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Computer Engineering. 2007, 33(01): 47-49. https://doi.org/10.3969/j.issn.1000-3428.2007.01.016This paper first narrates the characteristic of mobile agent and the rules of query containment and merging, then, based on it, proposes a query transaction strategy. By incorporating queries, the amount of query becomes lower, and by using mobile agent, the network communicating amount decreases.
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Computer Engineering. 2007, 33(01): 50-52. https://doi.org/10.3969/j.issn.1000-3428.2007.01.017Data cleaning should be done before data mining in order to improve data quality of data warehouse. ETL is a crucial process of constructing data warehouse, which includes data cleaning. Examining and eliminating approximately duplicated records is one of key needed solution for data cleaning and data quality improving. This paper introduces the position-coding technology to ETL of data warehouse, presents a new examining algorithm of approximately duplicated records, and brings forward a dynamic method of variant level match thresholds. Experimental comparison with the previous work indicates that the method proposed is effective.
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Computer Engineering. 2007, 33(01): 53-55. https://doi.org/10.3969/j.issn.1000-3428.2007.01.018This paper discusses characteristic of public traffic network and the auto-adapted plan algorithm. It establishes the geometry model and the data model of public traffic network, designs the optimal shortest-path and auto-adapted plan algorithm, analyzes its complexity, and completes the graphed demonstration at client side based on GIS. As one of the core modules in the traffic information management platform, the algorithm’s feasibility and efficient is confirmed during the actual application.
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Computer Engineering. 2007, 33(01): 56-58. https://doi.org/10.3969/j.issn.1000-3428.2007.01.019The Smith_waterman algorithm, used for the pair-wise biological sequence alignment, is one the most important method in bioinformatics. However, its time and space complexity are both O(mn), prevents it from being used for large sequences. Here, based on the parallel computational model, the HPM model, the parallelism and the locality of the algorithm is investigated and the hierarchical block pipeline parallel method is presented. Experiments of aligning sequences of different scale, are designed and the results are consistent with the theoretical conclusion.
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Computer Engineering. 2007, 33(01): 59-61. https://doi.org/10.3969/j.issn.1000-3428.2007.01.020A new type of mechanism for Intranet resources sharing and integration is given, which is to build up a real-time, high-efficiency, intelligent software platform for Intranet resource publishing, sharing, integrating and downloading. The platform has the feature of maximizing the integration of the resources in an Intranet so that users can make full use of them, by searching and downloading what they need at least time in an easy way. This resource sharing platform can help to make the efficiency of resource publishing, sharing, downloading and utilizing in an Intranet much higher, and also the average load of the Intranet more balanced. The design and key technique of implementation are discussed.
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Computer Engineering. 2007, 33(01): 62-64. https://doi.org/10.3969/j.issn.1000-3428.2007.01.021By analyzing the property and characteristics of D( the minimum merge dependency set of F) when D has weak left side conflict or weak left side conflict, the notions of Ps(join-lossless, FD and SNF), condition T are introduced. On this basis, the scheme decomposition is discussed and the result concludes that when D has weak left side conflicts or weak right side conflict or doesn’t meet condition T, the decomposition meeting Ps is α-cyclic, laying the foundation for further investigation of α-acyclic decomposition.
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Computer Engineering. 2007, 33(01): 65-67. https://doi.org/10.3969/j.issn.1000-3428.2007.01.022J2ME M3G(Mobile 3D Graphics API) specifies the Java 3D graphics API and framework on the mobile facilities. Applications programmed in M3G can run on different equipments and platforms. Because it is complicated in the design and implementation of RayIntersection in M3G, this paper summarizes the reference model and theory according to the M3G library that it have been developed on XORP. And it restructures the implementation based on them.
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Computer Engineering. 2007, 33(01): 68-70. https://doi.org/10.3969/j.issn.1000-3428.2007.01.023The software architecture of EEJBM is the two-layer distribute component software architecture. In order to gain the high performance for the remotely method invoking, it optimizes two points: the first is using register-provide method to get the high performance server’s location, the second is using EJBPOOL to initialize the EJB HOME’s connection beforehand. The forecasting arithmetic is discussed and analyzed in different area. The experimental results show that the new EJB software architecture can get good result in improving the performance and efficiency of distribute system.
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Computer Engineering. 2007, 33(01): 71-73. https://doi.org/10.3969/j.issn.1000-3428.2007.01.024It is always the difficulty to find out the “same entity from different sources(SEDS)” data in the data cleaning process of the data warehouse. The SEDS data are the same real world entities represented or stored differently in different data sources. The traditional data cleaning method costs a lot of system resources on finding and correcting such data, while the result is not ideal. With the digitization storage of the data, a new algorithm is proposed to find out the SEDS. The algorithm can reduce the comparison among the data effectively, and keep the quality at the same time.
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Computer Engineering. 2007, 33(01): 74-76. https://doi.org/10.3969/j.issn.1000-3428.2007.01.025A dynamic memory detection module DDMEM for C/C++ languages on Linux platform is designed to solve the errors of dynamic memory management. The malloc() dynamic distribution function is replaced by customized ddmemMalloc(). And a share library DDMEM is achieved. The module can detect memory leak, write overflow, free wild pointer and mismatch using of memory functions of the executable files. Finally, an instance to test functions mismatch and comparing between the DDMEM and a representational test tool Memwatch is carried to validate the effectiveness of method and module.
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Computer Engineering. 2007, 33(01): 77-79. https://doi.org/10.3969/j.issn.1000-3428.2007.01.026In order to improve the real-time performance of the Linux system, real-time capability improving methods provided by some company or organization is analyzed. A mechanism called “Entering a critical section is allowed only if the operation finishes before the execution of next real-time task” is introduced, together with the implementation of priority ceiling protocol and using the kernel thread to replace the normal ISR. The priorities of real-time tasks are ensured, the priority inversion situations are avoided and the interrupt latency is short and predictable. The method is applicable to embedded systems and other real-time sensitive situations.
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Computer Engineering. 2007, 33(01): 80-82. https://doi.org/10.3969/j.issn.1000-3428.2007.01.027The concept of colored synchronized-nets is proposed on basis of colored petri-nets, and a workflow process model named colored logic-nets (CL_net) is constructed according to colored synchronized-nets. A concrete instance is introduced to describe the methodology of process description using CL_net, and to show the practicability and popularizability of CL_net, reachability graph is employed to analyze the feasibility of the process.
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Computer Engineering. 2007, 33(01): 83-85. https://doi.org/10.3969/j.issn.1000-3428.2007.01.028Based on research and analysis of traditional embedded operating system security theories and technologies, combining with characteristics of embedded operating system, this paper puts forward a security kernel frame fit for embedded operating system: ESK(embedded security kernel). It has the characteristics as follows: self-determination configuring security attributions, mandatory access control, security signs and multi-strategy determinant. Through the reconstruction of Win CE operating system, the validity of the security kernel frame is validated.
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Computer Engineering. 2007, 33(01): 86-88. https://doi.org/10.3969/j.issn.1000-3428.2007.01.029As an important part of the software engineering, software test has a crucial effect on improving software quality and reliability. In white box test tool, WBoxTool, the program is tested automatically using visual instrumentation and monitoring technology for standard C/C++ programs. The instrumented program can be run automatically, and the program dynamic information which to be analyzed lately can be collected at the same time. The technology of code analysis and instrumentation test which has been used in the WboxTool is described, and some test examples are carried to illustrate this approach.
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Computer Engineering. 2007, 33(01): 89-91. https://doi.org/10.3969/j.issn.1000-3428.2007.01.030A method to integrate Web Service components and multi-agent system(MAS) is presented, the architecture of the integrated system is designed, and the frame system is implemented in Java as well. The intelligent Web Service and multi-agent system interacting across heterogeneous platform is realized.
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Computer Engineering. 2007, 33(01): 92-94. https://doi.org/10.3969/j.issn.1000-3428.2007.01.031The paper presents an auto-mapping method from business process execution language for Web Services (BPEL4WS) to π-calculus, checks the deadlocks property of the system expressing by π-calculus using the mobility workbench (MWB) and illustrates the approach.
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Computer Engineering. 2007, 33(01): 95-97. https://doi.org/10.3969/j.issn.1000-3428.2007.01.032Although sessions reconstruction is an important step in Web log mining, the sessions recognized by existing methods are not accurate. An algorithm resolving this problem is proposed. This paper improves the Timeout method with the algorithm. Finally the algorithm enhancing the quality of Web log sessions is proved by experiments.
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Computer Engineering. 2007, 33(01): 98-100. https://doi.org/10.3969/j.issn.1000-3428.2007.01.033This paper proposes a kind of new GML dataflow and compressed algorithm, studies GML structure and data separate dynamically and compress dynamically, multi-thread technology is adopted in order to parallel transmit, and then receive the data and solve the course that depresses dynamically and amalgamates dynamically. The experimental result indicates that this method has actual meanings in improving GML data transmission efficiency by a wide margin.
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Computer Engineering. 2007, 33(01): 101-103. https://doi.org/10.3969/j.issn.1000-3428.2007.01.034According to the research on process of network data collection and processing, this paper brings forward a rule-based method for network data collection and processing combined with practice project. The method encapsulates the logic of network data collection and processing by business rules, and organizes the business rules through object-oriented Rete algorithm. Data collection and processing systems adapted this method are more flexible and effective. And business logic and process are separated by this method. By focusing on customizing the rules with good readability depend upon the practical condition of the network, rather than compiling and maintaining messy, tangled business determinant statements.
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Computer Engineering. 2007, 33(01): 104-105. https://doi.org/10.3969/j.issn.1000-3428.2007.01.035This paper introduces the architecture of NIDS data distribution system. It focuses on how to develop its key component, effective load balancer and gives the implementation using network processor. It’s proved to be low-cost, short-term and scaleable to implement NIDS load balancer based on IXP2400 by experiment. It successfully finishes the task of data distribution, so that the detection performance of the system is improved.
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Computer Engineering. 2007, 33(01): 106-107. https://doi.org/10.3969/j.issn.1000-3428.2007.01.036Resilient packet ring (RPR) technology is optimized for robust and efficient packet networking over a fiber ring topology. RPR networks have the ability to carry multiple services, including jitter-and latency-sensitive traffic such as voice and video in addition to Ethernet and Internet protocol (IP) services. This paper presents the routing method of the packet going to the RPR ring network and its design. It is succeeded to resolve the updating of tens of thousands of routing table, the shaking of complex RPR topology database, high cost of hardware storage space and the spending problem of CPU.
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Computer Engineering. 2007, 33(01): 108-111. https://doi.org/10.3969/j.issn.1000-3428.2007.01.037Based on the research of virtual router and MPLS, this paper designs and implements a virtual router that supports MPLS, moreover, it makes studies on the application of virtual router in the experimental system of BGP/MPLS VPN. Also, the paper presents an effective solution for the system that enables each user to configure and operate independently, provides all the users a common topology of the network and consume relatively fewer software resources as well, effectively addresses the problem brought by the simultaneous operation of a large number of people.
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Computer Engineering. 2007, 33(01): 112-114. https://doi.org/10.3969/j.issn.1000-3428.2007.01.038LEPS is a multihop routing protocol in TinyOS. It forms a tree-like topology in the network with a shortest-path-first algorithm. In this topology, each node delivers the sensed data to its parent node, and the parent node forwards it to the sink node along the optimized path. LEPS routing also takes the link quality into account in choosing parent node to improve reliability. This paper analyses the principle and implementation in TinyOS. An experiment in an practical sensor network is also proposed. LEPS routing can form and maintain the data gathering tree in the network, but the link among sensor nodes are not stable, and network topology changes frequently.
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Computer Engineering. 2007, 33(01): 115-116. https://doi.org/10.3969/j.issn.1000-3428.2007.01.039The gateway of wireless sensor network, which is the unique data exit, plays a very important role in the network. This paper introduces the communication architecture of wireless sensor network, and analyzes the features and functions of the gateway, then compares several access technology of the gateway. Based on these, the solution of gateway based on CDMA model is put forward.
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Computer Engineering. 2007, 33(01): 117-118. https://doi.org/10.3969/j.issn.1000-3428.2007.01.040To alleviate the parameter dependence problem of random early detection (RED) algorithm, an improved method is proposed. The main idea is to adaptively adjust the parameter according to the changed “price” presented in the network traffic optimization theory. The simulation results show that the improved algorithm can improve link utilization, decrease packet loss rate and the average length of buffer.
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Computer Engineering. 2007, 33(01): 119-121. https://doi.org/10.3969/j.issn.1000-3428.2007.01.041An improvement method based on frequency division multiple access (FDMA) for routing is put forward in mobile ad hoc networks. A new method employing collision detection mechanism which embodies the idea of control center transmission is used to announce the route failures. An analysis of this solution is followed to show its advantages in enhancing the capacity of overall networks and delays. The results can be used to demonstrate the good throughput over previous methods.
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Computer Engineering. 2007, 33(01): 122-124. https://doi.org/10.3969/j.issn.1000-3428.2007.01.042The paper studies thorough the technology of Oracle advanced replication. It analyzes how to use the technology of advanced replication of Oracle database achieving data coherence in every site of distributed system, and uses the means of PL/SQL realizing the produce of replication. Data replication guarantees effectively the system’s normal operation and data’s integration and consistency.
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Computer Engineering. 2007, 33(01): 125-127. https://doi.org/10.3969/j.issn.1000-3428.2007.01.043The article describes CSBP control technology for guaranteed QoS service. It can guarantee the end-to-end delay of per-flow. Data flows get through Net having exact upper delay, and core routes are stateless. CSBP control technology syncretizes the benefits of IntServ and DiffServ, offers high quality of guaranteed services, at the same time it gives attention to the using rate of net resource and extending ability.
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Computer Engineering. 2007, 33(01): 128-130. https://doi.org/10.3969/j.issn.1000-3428.2007.01.044In the process of digital watermark theory research, digital watermark is similar to communication system. By introducing the concept of watermark channel into digital watermark, the watermark channel and its capacity are studied for helping to design watermark embedding and attacking algorithms. Based on watermark channel with side information and whether the side information is known to the watermark encoder and decoder, watermark channel is classified into four sorts as following: watermark channel which the encoder and decoder do not know the side information, or watermark channel which only the encoder knows the side information, or watermark channel which only the decoder knows the side information, or watermark channel which the encoder and decoder all know the side information. The corresponding channel capacity is analyzed. A watermark channel capacity with embedding factor is varying monotonously with watermark embedding factor.
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Computer Engineering. 2007, 33(01): 131-132. https://doi.org/10.3969/j.issn.1000-3428.2007.01.045Analyses are made on the security threats and system flaws of present shared verification signature schemes, and an improved shared verification signature scheme based on hyper-elliptic curves cryptosystem that can gain a wide application in computer and wireless communication network is presented. The probabilistic encryption algorithm in the scheme avoids the relevance between different signatures generated by the same signer, prevents coalition and generalized signature forgery. Further analyses also justify its brevity, security, high efficiency, and thus considerable improvement on system overheads regarding software and hardware application.
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Computer Engineering. 2007, 33(01): 133-135. https://doi.org/10.3969/j.issn.1000-3428.2007.01.046Since there are many differences between OSGi service platform and general open distributed service environment, the authentication protocol for the general system does not suit the OSGi service platform. Considering the shortcoming of the existing authentication protocol for the OSGi such as the mass operation and the inconvenience of creating and distributing secret keys, a new protocol is proposed. It is based on the KryptoKnight and X.509 protocols, combining the advantages of the symmetric and public key cryptography. It meets the requirements of the OSGi, including manageability, minimality and single-sign on.
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Computer Engineering. 2007, 33(01): 136-138. https://doi.org/10.3969/j.issn.1000-3428.2007.01.047This paper analyzes and contrasts the difference between conventional access control objects and share device resources. It presents device resource characteristics, such as time-dependent permit diversity privilege, access capacity and process-dependent. According to the four key characteristics and role-based access control model, it introduces several concepts such as dynamic actor, permanent role and device access policy etc. A remote device access control (RDAC) model is presented. This model satisfies the requirement for describing online device and access control.
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Computer Engineering. 2007, 33(01): 139-141. https://doi.org/10.3969/j.issn.1000-3428.2007.01.048Based on the features of digital cinema system and digital rights management technology, this paper proposes a DRM system for digital cinema. Manifold security technologies are adopted, such as encryption technology, digital signature technology and right expression language technology. This system can grant and manage the users’ rights, and protect the digital films’ confidentiality and integrity.
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Computer Engineering. 2007, 33(01): 142-144. https://doi.org/10.3969/j.issn.1000-3428.2007.01.049Malicious tampering with the type of document to conceal identity documents so as to entice users to visit real structure, avoiding detection and hiding data is the most common computer crime means. This paper presents a novel statistical method to identify document types, which recognizing effectively the attributes of the tampered document types. According to that the same type of documents are similar with the statistical features in multidimensional space, the basic assumption that judges this similarity is given, a model based on Euclidean distance spherical space toroidal model and k-spheroid space toroidal model are designed. Meanwhile, both models are optimized by the heavily weighted Euclidean distance based on the document statistics, and the correctness and efficiency of the similarities judgment are improved.
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Computer Engineering. 2007, 33(01): 145-147. https://doi.org/10.3969/j.issn.1000-3428.2007.01.050On-line tax returns systems are inevitably subject to security exposures and risks of the global Internet. This paper presents a security design for tax returns system that supports mobile end user devices. The proposed approach is designed to address new security requirements due to the electronic signature law which aims to provide a legal basis for electronic transactions. The design makes use of and combines the advantages of PKI mechanism and simple password authentication. It is a lightweight security approach that can operate efficiently on resource-scarce mobile devices.
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Computer Engineering. 2007, 33(01): 148-150. https://doi.org/10.3969/j.issn.1000-3428.2007.01.051A new kind of access control model——PBACWS(process based access model for Web Services) is invented concentrating on the low coupling and dynamic change characters of Web Services. Under the PBACWS model, concepts of meta service and meta permission are put forward to give better description of Web Services and it changes the tradition way of assigning user with role to use service permission token as the authorization entity. In this model, more effective access control for Web Services is made through assigning the task process with the dynamic service permission token.
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Computer Engineering. 2007, 33(01): 151-152. https://doi.org/10.3969/j.issn.1000-3428.2007.01.052With undertaking the entire basis for the modern Internet security, authentication; a mechanism is proposed here which incorporates the EAP authentication framework to SIP (session initiation protocol) network. This paper shows SIP authentication can be extended via EAP (extensible authentication protocol) authentication framework and existing AAA (authentication, authorization and accounting) infrastructure can be reused for authentication of SIP users. The authentication is implemented using DAIAMETER base protocol. The base protocol tools using lightweight directory access protocol (LDAP) interface must be used, and subset of the DIAMETER NASREQ (network access server request) application command code and AVP must be used for extensible authentication protocol (EAP)transport while implementation.
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Computer Engineering. 2007, 33(01): 153-155. https://doi.org/10.3969/j.issn.1000-3428.2007.01.053Using support vector machine(SVM) active learning in intrusion detection to resolve the problem of machine learning in the small sample size. This paper provides a framework of intrusion detection system based on SVM active learning, and it also provides a SVM active learning algorithm for intrusion detection system, discusses how the composition of the unlabeled sample set, the size of the unlabeled sample set and the parameter of the kernel function affect the accuracy of the SVM. Compared with the traditional SVM self-learning algorithm, the experiment shows active learning algorithm can immensely reduce the number of the training date and efficiently improve the performance of the classifier in intrusion detection system.
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Computer Engineering. 2007, 33(01): 156-158. https://doi.org/10.3969/j.issn.1000-3428.2007.01.054This paper presents a robust software watermark scheme which exploits dynamic graphs to represent the watermark and employs their inner structures to tamper-proof the watermark itself, moreover it also utilizes concurrently controlled multithread to implement redundant embedding and reliable extraction of the watermark.
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Computer Engineering. 2007, 33(01): 159-160. https://doi.org/10.3969/j.issn.1000-3428.2007.01.055Analyses are made on the security threats of present E-cash schemes, and a traceable faire E-cash scheme based on hyper-elliptic curves cryptosystem that can gain a wide application in computer and wireless communication network is presented. The probabilistic encryption algorithm in the scheme avoids the relevance between different E-cashes generated for the same buyer. The independence of E-cash security on the hypothesis of an absolutely trustable party in the scheme prevents coalition attack and generalizes signature forgery. Further analyses also justify its brevity, security, high efficiency, and thus considerable improvement on system overheads regarding software and hardware application.
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Computer Engineering. 2007, 33(01): 161-163. https://doi.org/10.3969/j.issn.1000-3428.2007.01.056Test and validation of access control is a crucial part of the security evaluation of the system. A testing approach by extending GFAC is proposed, automatically to test the access control service according to requirements of security evaluation based on common criteria. The implementation of testing on Linux+RSBAC demonstrates the approach available.
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Computer Engineering. 2007, 33(01): 164-166. https://doi.org/10.3969/j.issn.1000-3428.2007.01.057In self-organized public-key management scheme it just considers the load balance, the efficiency of the certificate updating service is low. This paper presents a certificate update protocol based on probabilistic reliable multicast. The new scheme includes two parts: the transmission of update information and distributed update service. In the first part the node multicasts the update information to the nodes that are selected from its local certificate repository which has already had some route information in its local route table. In the second part the node that has not received the new update information can get the certificate update service from the node that has received the update information instead from the certificate issuer itself. It fully makes use of the existing route information to reduce the traffic cost caused by searching route information, and reduces the load of the certificate issuer achieving load balance by distributing the service task to multi-nodes in the network, and it also provides predictable probabilistic analysis of the scheme’s efficiency.
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Computer Engineering. 2007, 33(01): 167-169. https://doi.org/10.3969/j.issn.1000-3428.2007.01.058Researched on several recently widely used modular multiplication algorithms, adopted the ideal of window division, estimating quotient, and modular 2n easy to be calculated, which is used in Montgomery modular multiplication algorithm, a new fast calculating AB mod N algorithm based on addition is presented, which introduces pre-calculating by modular N. When the length of modular N is 1 024-bit and the length of window is 6, on the average, the new algorithm requires only 693 times 1 024-bit addition to calculate AB mod N. Comparing with current additional modular multiplication algorithm, the computing complexity is reduced largely.
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Computer Engineering. 2007, 33(01): 170-172. https://doi.org/10.3969/j.issn.1000-3428.2007.01.059A new access control model based on security assertion markup language(SAML) is added to campus grid system. Workflow of access control and the authorization service are discussed. The attribute-based access control policy and the security assertion mapping solution are also adopted in this system. It integrates with the portal, which is in charge of the interface between resource consumers and resource providers. It shows more flexibility and reliability.
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Computer Engineering. 2007, 33(01): 173-175. https://doi.org/10.3969/j.issn.1000-3428.2007.01.060This paper proposes a forward secure digital signature scheme based on bilinear pairings. It divides signature course into several periods. In each period, the public key is steady, but private key is always changed. Furthermore, the next private key is produced by one-way function and the current secret key. So this scheme satisfies forward security. The new signature scheme satisfies forward security. It is a easy to realize, prompt to update the secret key, highly secure scheme. It also gives the proof on security and efficiency, forward security.
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Computer Engineering. 2007, 33(01): 176-177. https://doi.org/10.3969/j.issn.1000-3428.2007.01.061After analyzing the mechanism and the expansion of technology for Linux Netfilter/Iptables, the characteristics of the P2P protocol, through expanding kernel lib based on the Linux system, this paper implements user data space and kernel space data interchange through sharing lib, expands firewall rule, implements P2P flow control, and according to emerging P2P business to update the rule set, with the good performance of expansion.
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Computer Engineering. 2007, 33(01): 178-180. https://doi.org/10.3969/j.issn.1000-3428.2007.01.062Certificate verification is a key component in implementation of PKI. According to the PKIX, it includes two steps to verify a certificate: certificate path construction and certificate path verification. But the PKIX makes silence on certificate path construction and there are very little existing literatures that discuss this issue. So this paper proposes a distributed algorithm in the reverse direction to construct a certificate path.
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Computer Engineering. 2007, 33(01): 181-183. https://doi.org/10.3969/j.issn.1000-3428.2007.01.063Combining Camenisch et al’s method of inserting mark with proof and Abe et al’s partial blind signature, a new off-line E-cash system without TTP and the concept of validity duration of E-cash are proposed. The bank demands users to decrypt the mark of the coin when tracing is needed so that the user and coin can be linked together. So the system resolves the problem of the E-cash anonymity control without TTP simply and practically. The E-cash system has the properties such as little calculate payload and high on-line transaction efficiency. Above all, the storage size of the transcript database created and maintained by bank is controllable.
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Computer Engineering. 2007, 33(01): 184-186. https://doi.org/10.3969/j.issn.1000-3428.2007.01.064An Agent-based negotiation model is proposed. The mathematic models of negotiation argument and result acceptability are established on the base of fuzzy sets. A satisfactory agreement is reached by solving negotiation models with constraint relaxing method. The bilateral multi-issue negotiation process is detailed and the Agent negotiation prototype is designed which shows the above-mentioned model is a win-win method.
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Computer Engineering. 2007, 33(01): 187-189. https://doi.org/10.3969/j.issn.1000-3428.2007.01.065Many clustering algorithms are not appropriate for categorical data. Therefore, a clustering algorithm based on the longest frequent closed itemsets (LFCIs) is presented. With the adaptation of traditional frequent-pattern tree, the LFCI of each transaction is found out accordingly. Due to two aspects of important attribute of LFCI, it can be considered as the description of the corresponding transaction. As a result, the clusters derive from LFCIs directly without a large intermediate set of frequent itemsets. The experiment results demonstrate the feasibility and robustness of this method.
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Computer Engineering. 2007, 33(01): 190-192. https://doi.org/10.3969/j.issn.1000-3428.2007.01.066A brain computer interface presented using electroencephalogram(EEG) signals are the subjects that have to think of the multiplication task. EEG signals from 4 subjects are recorded at occipital scalp, while they are in the state of the multiplication task and the resting state. The spectral power in the 3 bands: 8~10Hz, 11~13Hz and 14~30Hz, is estimated using the Welch method respectively. A ratio of the average of the spectral power in each of the three bands to the average in 2~30Hz is designed as classification features. The multiplication task is detected by a support vector machine classifier. The experimental results show that the method is feasible, practical, and all accuracies are more than 94.44%, while maxim accuracy is 98.89%. Because the two channels are only used, the method is more convenient in practice for constructing letters, controlling a wheelchair and so on.
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Computer Engineering. 2007, 33(01): 193-194. https://doi.org/10.3969/j.issn.1000-3428.2007.01.067An algorithm for images matching based on graph cut and epipolar geometric constraint is proposed. The two original images are rectified by epipolar geometric constraint to make their epipolar lines parallel to the scan-lines. So the 2D matching of images is simplified to that of 1D. Then the matching disparities can be gained by the 1D matching algorithm based on graph cut. The label is 1D in the energy function. Therefore, the searching range is greatly decreased, and the rate of matching is improved.
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Computer Engineering. 2007, 33(01): 195-197. https://doi.org/10.3969/j.issn.1000-3428.2007.01.068Maintenance in aviation is one of the important factor related to the safety and efficiency of civil aviation, and is the base for flight as well. It is necessary to build an early warning expert system for maintenance errors in civil aviation. The paper introduces the method based on the rule-based uncertainty reasoning and case-based reasoning in the field of early warning expert system for maintenance errors in civil aviation by means of Agent technology. It describes the architecture of the early warning expert system and the main implementation technique. The research gives a new idea and foundation for further study of early warning for maintenance errors in civil aviation.
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Computer Engineering. 2007, 33(01): 198-199. https://doi.org/10.3969/j.issn.1000-3428.2007.01.069In order to solve a kind of non-identical parallel machine scheduling problem for minimizing the make-span, a parallel hybrid genetic algorithm is suggested. Its coding method is simple and can effectively reflect the scheduling policy, and the methods of the generation of the initial population, crossover and mutation are also researched. Considering the requirements of adapting it to this kind of lager scale problem and real-time scheduling, it is parallelly implemented under the mode of master-slave control networks. The computational results suggest that the genetic algorithm is efficient, and advantageous over genetic algorithms and heuristic procedures, and fit for large-scale non-identical parallel machine scheduling problem.
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Computer Engineering. 2007, 33(01): 200-203. https://doi.org/10.3969/j.issn.1000-3428.2007.01.070Automatic locating the region of gluteus medius is crucial for implementing the lossless grading system for pigs based on computer vision. This paper presents an improved locating method based on geometrical features to locate the region of gluteus medius automatically. And a comparison with the conventional template match method has been performed, experimental results show the presented method is better than template match method to locate the region of gluteus medius and has a perfect effect.
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Computer Engineering. 2007, 33(01): 204-206. https://doi.org/10.3969/j.issn.1000-3428.2007.01.071A method on video-based face recognition using Laplacianfaces and Hidden Markov Models(HMM) is proposed. During the training process, all the training images in each subject are projected into the obtained Laplacianspace and corresponding feature vectors, which will be used as observation vectors in the HMM training are generated. The statistics of training video sequences of each subject, and the temporal dynamics are learned by an HMM. During the recognition process, the temporal characteristics of test video sequence are analyzed over time by the HMM, and the highest score among the likelihood scores provided by HMM estimates the identity of the test video sequence. Experimental results show that the proposed method can get satisfied performance in video-based face recognition.
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Computer Engineering. 2007, 33(01): 207-208. https://doi.org/10.3969/j.issn.1000-3428.2007.01.072A method of automatically recognizing and matching artificial signs is discussed, which falls into two parts: a set of artificial sign design with respective characteristics and a method of automatically recognizing and matching the signs. The latter contains several parts: sign recognition, sign demarcation and sign matching. This method is mainly implemented by hardware circuit, also there are some programs in it . It will resolve the problem mentioned above and improve the efficiency of recognizing and matching.
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Computer Engineering. 2007, 33(01): 209-211. https://doi.org/10.3969/j.issn.1000-3428.2007.01.073This paper presents the quality evaluation criterions. Based on these criterions it takes three document clustering algorithms for assessment with experiments. The comparison and analysis show that STC(Suffix Tree Clustering) algorithm is better than k-Means and Ant-based clustering algorithms. The better performance of STC algorithm comes from that it takes accounts of the linguistic property when processing the documents. Ant-based clustering algorithm’s performance variation is affected by the input variables. It is necessary to adopt linguistic properties to improve the Ant-based text clustering’s performance.
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Computer Engineering. 2007, 33(01): 212-215. https://doi.org/10.3969/j.issn.1000-3428.2007.01.074Based on artificial psychology and common emotion theory, combined with personality and OCC model in 3-dimension emotion space, this paper builds an emotion model and adopts the model as feeling kernel, realizes a virtual feeling robot by the application software tools of VB, ViaVoice, KeDaXunFei, TalkingShow. The virtual feeling robot not only has the ability of study and memory, but also has the ability of emotion exchange.
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Computer Engineering. 2007, 33(01): 216-218. https://doi.org/10.3969/j.issn.1000-3428.2007.01.075This paper introduces a new pattern combining search technology and translation technology well, with which an assisted translation search engine system named Yiba is fulfilled. The core of the assisted translation search engine is described, including spider, identification and purification to pages, arithmetic of dividing and matching sentences, establishment of indexes and searches.
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Computer Engineering. 2007, 33(01): 219-221. https://doi.org/10.3969/j.issn.1000-3428.2007.01.076Reactor decommissioning is a huge system engineering, which requires optimal design and effectiveness analysis. Using VR technology, a virtual 3D reactor can be constructed and be decommissioned without any danger. The simulation system based on VR provides analysis tools for decommissioning engineering, offers evidences for making decision and finding key problems of decommissioning, what’s more, it can contribute to operation training and decommissioning datum management. After analyzing requirements of reactor engineering, a reactor decommissioning simulation system based on VR is designed, key VR techniques of this system such as scene construction, virtual dismantlement, virtual decontamination, radiation dose visualization and virtual operation are discussed. Depending on research results, a primary application system is realized according to one specific reactor decommissioning project.
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Computer Engineering. 2007, 33(01): 222-223. https://doi.org/10.3969/j.issn.1000-3428.2007.01.077How to make the compressed image preserve certain auto target recognition(ATR) performance is an important problem. Region of interest (ROI) mechanism in JPEG2000 standard is an appropriate choice. This paper chooses ROI by constant false alarm ratio(CFAR) detector, then compresses the image by JPEG2000 algorithm. Comparing with JPEG, vector quantization and SPIHT methods, the approach described in this paper preserves better ATR performances.
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Computer Engineering. 2007, 33(01): 224-226. https://doi.org/10.3969/j.issn.1000-3428.2007.01.078This paper introduces the scene description of binary format in MPEG-4 standards and two extensible textual format of XML: XMT- A format, XMT- Ω format; the mapping between BIFS and their nodes, attributes and fields. It also gives the function structure of MPEG-4 scene video manufacture and release system and the system layer analysis based on XMT. The interactive multimedia scene video which makes use of the system can manufacture the program for Internet teaching and play video on demand of long range. The system established on MPEG-4 standards raises the quantity of the long range teaching, satisfies the interactive necessary of user and scene video. XMT which is a central descriptal format allows the content exchange and interoperability between MPEG-4, SMIL and VRML standards.
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Computer Engineering. 2007, 33(01): 227-229. https://doi.org/10.3969/j.issn.1000-3428.2007.01.079According to the dynamic information of manufacture resource, the process plan system should make process plan decision accurately and timely for e-manufacture. The process plan includes three stages, part information input, feature process selection and process plan decision-making. Error back propagation neutral network algorithm has been used to solve feature process chains fuzzy match. The dynamic information of resources and rules of process plan are regarded as the integrated restriction conditions, and the genetic algorithm is adopted to realize the process route optimization selection based on the dynamic resource information. It is effective to solve resource conflict in production schedule. Finally, the feasibility of this design method is proved by a case running on the prototype that is developed by Java.
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Computer Engineering. 2007, 33(01): 230-231. https://doi.org/10.3969/j.issn.1000-3428.2007.01.080According to the characteristics of nonlinearity, large delay and unprecision physical model and requirements for temperature control in the low noise block(LNB)down converter temperature system, a novel bi-fuzzy control method with proportional-integral-tuning unit, which optimizes the control rule by adjusting factors, is developed to realize the temperature control for LNB. Moreover, its implementation with DSP TMSLF2407A is also given. Smooth actions of the controller during switching are guaranteed by using fuzzy inference. The experimental results show that the bi-fuzzy controller is much better than the conventional PID controller, and can meet the design requirements for the LNB temperature controller.
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Computer Engineering. 2007, 33(01): 233-235. https://doi.org/10.3969/j.issn.1000-3428.2007.01.081Applying Ethernet to industry’s network control system is the development direction of control network. However, Ethernet leads to undetermined response time in real-time control system because Ethernet medium access control CSMA/CD is the contention and has no maximum transmission delay guarantee. Switched Ethernet can eliminate the uncertainties in the traditional Ethernet operation, thus switched Ethernet leads to the dramatically improved performance. A Theoretical maximun communication delay in industrial Ethernet is analytically derived. Based on the simulation of servomotor PID digital network control system, the paper also evaluates the performance of the servomotor network control system under different network protocols and loads. This offers the basis of theory analysis for the design of the network control system.
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Computer Engineering. 2007, 33(01): 236-238. https://doi.org/10.3969/j.issn.1000-3428.2007.01.082A restriction conditions set is constructed, which includes six restriction entities and six relationships among them, for embedded vehicle navigation system. Under this restriction conditions set, this paper presents a novel navigation route planning algorithm named Modify_Dij and builds a parallel display engine which can support dynamic indexing mechanism. The experiment results show that Modify_Dij and the parallel display engine have a good response time performance than others. They have been used in a real vehicle navigation equipment.
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Computer Engineering. 2007, 33(01): 239-240. https://doi.org/10.3969/j.issn.1000-3428.2007.01.083Current electronic equipment ATE cannot commonly monitor real-time online state during equipment works. This paper designs field embedded state monitor system with the technique of manifold noncontact sensors information fusion and wireless RS-232 serial port communication. A kind of embedded micro processor unit, S3C44B0X, and real-time operation system, μCOS –II are adopted to implement the synchronization and parallel processor of collecting the important parts of the equipment system signal and monitoring the real-time online state. It is the base of condition based maintenance and efficient leading prevention maintenance which can provide safeguard for equipment in good combat readiness state.
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Computer Engineering. 2007, 33(01): 241-243. https://doi.org/10.3969/j.issn.1000-3428.2007.01.084The machine layout problem is an NP-complete problem, it is very difficult, even impossible to find the optimum solution in a reasonable amount of time, so it can only be solved by use of the heuristic algorithms. The efficiency of the traditional simulated annealing algorithm is low and its solution is not good because of its repeated searching during the process of searching the new solution. The traditional simulated annealing algorithm is improved through adding memory function in the searching process. The improved simulated annealing algorithm can effectively avoid repeated searching, so the solution is better and the efficiency is higher, which is proved true through an example.
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Computer Engineering. 2007, 33(01): 244-246. https://doi.org/10.3969/j.issn.1000-3428.2007.01.085The data mining process of establishing the quality model is introduced, that could predict the mechanical properties of hot-rolled steel strip with the technological parameter. The quality model whose hit ratio of 5% deviation reach 0.508 is established by applying the technology of basic artificial neural network. The quality model whose hit ratio of 5% deviation reach 0.721 is established by applying the technology of layer-of-layer impending, and this model could meet current industrial demand fully.
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Computer Engineering. 2007, 33(01): 247-249. https://doi.org/10.3969/j.issn.1000-3428.2007.01.086This paper summarizes the function and the superiority of digital video monitoring system, proposes a novel network video monitoring system overhead construction, based on the development tendency of wireless network technology, introduces technical problems to solve to realize the novel video monitoring system, discusses the mechanism to enhance the performance of wireless network video service, and introduces the function of wireless proxy server.
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Computer Engineering. 2007, 33(01): 250-252. https://doi.org/10.3969/j.issn.1000-3428.2007.01.087The control-net for people aerial defence alarm system is an important subsystem and frail part, because the failure of it may directly lead to the failure of all the system. This paper proposes a communicate mechanism at the base of individual control-net, in order to improve the reliability for the connection between control-center and alarm end. Then the redundancy technique is introduced to our work based on the implement of control-net between control-center and alarm end through GPRS and PSTN. At the last part of the paper, the two control-nets are integrated seamlessly, when one control-net fails, the data would transmit through another one transparently, so the possibility of the failure of communication is decreased.
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Computer Engineering. 2007, 33(01): 253-255. https://doi.org/10.3969/j.issn.1000-3428.2007.01.088Applying laser measurement and Ad Hoc mobile wireless network technique in liquid measuring of molten steel carrier, there are five stations which constitute a temporary Ad Hoc network. Each station adopts MCS-51 MCU or industrial PC to real-timely process and deliver the data from laser measurement and achieve controlment of measure spot. The MAC layer adopts the protocol of CSMA, and uses non-insist arithmetic as the avoiding arithmetic. The route protocol of wireless self-organizing network is designed based on DSDV and DRS protocol, and validates its ability through reality analysis. The practical run also shows the network works in a good condition.
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Computer Engineering. 2007, 33(01): 256-258. https://doi.org/10.3969/j.issn.1000-3428.2007.01.089This article discusses the design and implementation of A-SMGCS vehicle terminals, which are used to fulfill the surveillance need for vehicle in airports. After a general description of the terminal elements and how they work together, this article discusses terminal’s hardware and software structures, electronic map design based on QNX embedded system, including the design of map engine, data structure and map matching, multi-thread program design in QNX. In the end, the terminal’s implementation and development direction in future is discussed.
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Computer Engineering. 2007, 33(01): 259-261. https://doi.org/10.3969/j.issn.1000-3428.2007.01.090Combined with the application of the storage array, the RAID system is achieved based on the Intel 80321 I/O processor. And the optimization of RAID5 system is put forward as follow: the implication of the application accelerator unit and the management strategy of the cache. It is proved that the performance of the system meets the expectations.
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Computer Engineering. 2007, 33(01): 262-264. https://doi.org/10.3969/j.issn.1000-3428.2007.01.091Some technologies about data warehouse & data mining are introduced into education, and an intelligent teaching & study analysis system based on Web, integrated with study, teaching, test and analysis is given. By learning the history data, this system can mine the study pattern of students and the association rules between teaching and study, in order to help the teachers and the students to enhance their efficiency.
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Computer Engineering. 2007, 33(01): 265-266. https://doi.org/10.3969/j.issn.1000-3428.2007.01.092This paper analyzes the service antinomy of the remote surveillance delivers within the IP network, discusses how to carry out solid hour that the numerical remote concentration surveillance system video frequency deliver. Combined on this foundation, the analytical video frequency MPEG-4 codes the standard, introducing the system structure model of a kind of remote surveillance system design and the key technique of the realizations. The system adoption video frequency MPEG-4 codes the standard, raises to compress the ratio, and carries out the software to solid the hour compress, the system video frequency delivers to return to put to adopt the mechanism of QOS with many road, carrying out a simple multimedia of RTP to deliver the agreement, the system delivers to have the bandwidth from adapt and obstruct to control the ability, the best customer who guarantees the system to carry the service quantity.
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Computer Engineering. 2007, 33(01): 267-269. https://doi.org/10.3969/j.issn.1000-3428.2007.01.093This paper presents a scheme of a real-time Chinese spam mail filtering system based on content analysis. The system works on Sendmail mail server under Linux. It utilizes Milter interface to get the real-time e-mail content, and then classifies and filters it combined with Chinese word segmentation and text categorization algorithms. It has high expansibility since it can embed many kinds of text categorization algorithms. Furthermore, these different text categorization algorithms are analyzed and compared by experiments.
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Computer Engineering. 2007, 33(01): 271-273. https://doi.org/10.3969/j.issn.1000-3428.2007.01.094On the basis of analyzing existing authority management system, this paper presents an universal and self-adaptive authority management system, takes advantage of using XML to describe function, entity class and operation message. This system can handle any changes which appear in the processes of system development, application and upgrade.
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Computer Engineering. 2007, 33(01): 274-276. https://doi.org/10.3969/j.issn.1000-3428.2007.01.095The management of the income is a multi-disciplinary edge subject studying perishable products marketing law of value, involving marketing, operational research, theory of decision making, microeconomics, mathematics, and software engineering. The management of the income is a kind of feed forward in essence, this determines that the model and the algorithm are foundations of management of incomes all the time. On the basis of forefathers’ research results and the inspiration from electron defied to jump to move, the paper proposes the prediction model based on excitation level of the flow of passengers, and solves the complicated n-value predict problem for flow of passengers well.
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Computer Engineering. 2007, 33(01): 277-279. https://doi.org/10.3969/j.issn.1000-3428.2007.01.096Home appliances have evolved from being single task devices to integrating several tasks in a particular device. The next step for home appliances is to transform into network appliances and accelerate the development of home automation. This research has the objective of adding a new method, called DO, to the session initiation protocol(SIP) in order to control these network appliances.
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Computer Engineering. 2007, 33(01): 280-282. https://doi.org/10.3969/j.issn.1000-3428.2007.01.097The innovated edge detecting and extracting technology helps accurately position objects in the photograph, thus able to automatically distinguish and alter the background color of the photograph, correct the object’s skin color, adjust the tolerance level, etc. Ensuring the photograph fulfills the resident identity card digital photograph specifications and requirements. When the technique is applied, not only are the results satisfactory, but also significant differences can be observed especially for some special groups of people after their photographs have been processed. This innovation allows the digital portrait photograph creation to be ever accurate, stable and efficient. In addition, because of its ability to be fully automated and highly intellectualized, photographs are able to be processed in large batches.
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Computer Engineering. 2007, 33(01): 283-284. https://doi.org/10.3969/j.issn.1000-3428.2007.01.098The combination of MIMO and OFDM is the core technique of B3G and 4G wideband wireless communication, which can effectively increase spectral utilization. Traditionally, design of communication system is simulated with Matlab. This paper realizes the simulation of 4*4 MIMO OFDM wireless communication system using SystemC. Research result demonstrates that MIMO OFDM system provides higher data rate and better performance, and SystemC is a fast operated and easy realized development platform which can save more PC resources.
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