05 November 2007, Volume 33 Issue 21
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Computer Engineering. 2007, 33(21): 1-2,5. https://doi.org/10.3969/j.issn.1000-3428.2007.21.001This paper presents an algorithm of point correspondence based on Laplacian spectra of graphs with probabilistic relaxation. Given two feature points sets, it defines Laplacian matrices respectively, analyzes the eigenvalues and eigenvectors of the matrices, and obtains the initial correspondence probabilities. The final matching results are acquired by using the method of probabilistic relaxation. Experimental results show that the method possesses comparatively high accuracy.
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Computer Engineering. 2007, 33(21): 3-5. https://doi.org/10.3969/j.issn.1000-3428.2007.21.002This paper proposes a subsequences partition algorithm for different width time window, focusing on the shortage of that by the same width time window. Aimed at dealing with the limitation of the approach, a new approach that divides the time series with different width time window is put forward. Due to the length of subsequences obtained by the new approach is different, the similarity between these subsequences can only be measured by the algorithm of DTW, while its calculation speed is slow. So a new distance measurement algorithm, nonuniform time series (NTS) is put forward. The approach and the algorithm are tested. Experimental result shows the superiority of the new approach and new algorithm.
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Computer Engineering. 2007, 33(21): 6-8. https://doi.org/10.3969/j.issn.1000-3428.2007.21.003The buffer analysis is the basic function in 2D GIS, but the research on the buffer analysis in 3D GIS is little. This paper analyzes the importance of 3D buffer analysis. It classifies the 3D buffer according to the geological application, whether the surrounding is uniform or not, and whether the barrier exists around or not. This paper proposes an algorithm for the 3D buffer-generation with the restriction, and discusses the algorithm for the 3D heterogeneous buffer-generation.
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Computer Engineering. 2007, 33(21): 9-11,1. https://doi.org/10.3969/j.issn.1000-3428.2007.21.004This paper presents the morphological method supported by the geographic information system (GIS) technology to disperse statistical socioeconomic-data of district region, and builds up the thematic map, just for the needs of drawing statistical thematic map. The procedure divides the disposed scope into the row-column grid-cells identically by the size, and each cell is simultaneously evaluated by the average value of the statistical data grouped by its containing region. The value in the matrix of coefficient for convolution is determined by the percentage of the building area in each corresponding cell, and the vicinity of a belted region containing the cell and rounding the core area, weighted by its neighbor-distance to core area. Applying the action of erosion or dilation on the prepared grid-map, it can easily build up the thematic map based on these grid-cell. Experimental result demonstrates the reasonableness and feasibility of the method.
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Computer Engineering. 2007, 33(21): 12-14. https://doi.org/10.3969/j.issn.1000-3428.2007.21.005This paper gives some basic properties of children and successors in the concept lattice. By making use of these properties, it presents an algorithm to generate all concepts and its lattice order. Given a formal concept, this algorithm can produce all the children and identify all successors from them. During its implementation, the set exact matching takes place of against subset testing operations which is at a high price and the better computation efficiency is achieved.
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Computer Engineering. 2007, 33(21): 15-17. https://doi.org/10.3969/j.issn.1000-3428.2007.21.006Current architecture-based software reliability evaluation is suitable for sequential software but not parallel software, and it is difficult to analyze the failure and restart behavior of component. To solve these problems, parallel software with pipe-filter style is selected as the research object and a new model is proposed to analyze the reliability of it by using time-based Petri nets. According to the characteristics of its model, a specifical solution to decompose and compute approximately the Petri net model is presented and it can avoid the explosion of state space. Numerical examples show the method is valid and convenient.
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Computer Engineering. 2007, 33(21): 18-20,2. https://doi.org/10.3969/j.issn.1000-3428.2007.21.007Reversible digital watermarking can reverse the marked media to the original state without any distortions after the hidden data is retrieved. Tian’s reversible data hiding algorithm using difference expansion is the algorithm whose capacity is the highest among all the reported examples, but its quality of watermarked carrier images is lower relatively. To avoid the unnecessary quality decline of watermarked images from excessive modulation to pixel pairs, this paper proposes an ECC based reversible digital watermarking difference expansion. The algorithm distinguishes pixel pairs into only two types, i.e. Type I and Type II. Its embedding, extraction, and recovery processes are symmetrical. The computation of the proposed algorithm is quite simple and execution time is rather short. The quality of watermarked images is improved largely, especially when the level of its payload is low.
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Computer Engineering. 2007, 33(21): 21-23,2. https://doi.org/10.3969/j.issn.1000-3428.2007.21.008Based on OGSA, this paper proposes an effective model for grid Web component resource organization, which considers service choice-making based on QoS. The organizing protocol and data structures required for implementing the model are given. The prototype implementation shows that framework is reasonable and effective, and it provides guarantee of the reliability of Web service assemble and service QoS.
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Computer Engineering. 2007, 33(21): 24-27. https://doi.org/10.3969/j.issn.1000-3428.2007.21.009Mean-shift-based visual target tracking is one of the hotspots in the field of computer vision. The model of the algorithm is simple, efficient and easy-to-implement, and it can handle the complex cases such as deformations and partial occlusions. Recent researches on scale adaptation of the tracking window and distributions of features improve the performance of such trackers. This paper introduces the development and the state of such kind of the algorithms.
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Computer Engineering. 2007, 33(21): 28-30. https://doi.org/10.3969/j.issn.1000-3428.2007.21.010When the real-time tasks are scheduled, μC/OS-Ⅱ takes use of single algorithm to assign the priority of tasks. Because of the singularity of determinant standard of priorty, the high deadline missing ration of real-time tasks influences the real-time scheduling performance seriously. This paper advances the assigning policy of priority of multi-parameter tasks and the task scheduling method in μC/OS-Ⅱ. Experimental results show that DMR of multi-parameter scheduling algorithm is 60.1%, and improvement of real-time scheduling performance.
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Computer Engineering. 2007, 33(21): 31-33. https://doi.org/10.3969/j.issn.1000-3428.2007.21.011Facing the demand of more efficient searching for the massive Web data, the parallel and distributed architecture is the possible method for constructing the large scale searching system. By using of multi-level structure, parallel method, and distributed framework, this paper mines the idle computing resources of Internet, proposes a Web data searching driving model, describes main components, model architecture, searching process, and parallel driving mechanism. The experimental results show that the model has good scalability and it can be fit for the applications of large scale Web searching system in Internet.
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Computer Engineering. 2007, 33(21): 34-36. https://doi.org/10.3969/j.issn.1000-3428.2007.21.012After analyzing the levels of large-scale parallel database monitor system, this paper realizes the dynamic monitor module in the middleware layer. This module adopts centralized monitor technology to get control information, and uses the subscribe and publish mechanism of ICE Storm to realize the publication and treatment of monitor message, and enables user to obtain real-time monitor information through Ajax and Web technologies, thereby ensuring the efficient services of database system and greatly facilitating the management in the complex database system.
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Computer Engineering. 2007, 33(21): 37-38,4. https://doi.org/10.3969/j.issn.1000-3428.2007.21.013Based on the idea of rapid prototyping, this paper introduces a unified platform for multidimensional data modeling. This platform provides a design environment of prototype for the OLAP applications designers, describes the users’ requirements with diagram, and shows the corresponding analysis results to the users immediately after a series of simple operations. Through this way, users can adjust and affirm their analysis requirements easily. And it provides the application designers with a guide, expedites the process of applications development.
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Computer Engineering. 2007, 33(21): 39-41. https://doi.org/10.3969/j.issn.1000-3428.2007.21.014This paper analyses characteristics of the management of processes and characteristic of IPCs in uClinux, studies design method of reliable embedded software based on uClinux process mechanism, brings forward a multi-level mechanism of self fault-check and fault-recovery based on special policy. Practice shows that the mechanism is effective.
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Computer Engineering. 2007, 33(21): 42-44. https://doi.org/10.3969/j.issn.1000-3428.2007.21.015Focusing on the difficulty of fee management and credit fee calculation in E-Learning, this paper analyzes the specific fee service, and presents a design for intelligent E-Learning charging system based on multi-layer architecture. It expounds the functions of each layer of the system and MVC model application. It describes the function module architecture in application service layer, and the intelligent arithmetic of credit fee calculation, and the common service interface design. The architecture has loose coupling, reusability, scalability and integrality, which has been approved in real system.
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Computer Engineering. 2007, 33(21): 45-46,4. https://doi.org/10.3969/j.issn.1000-3428.2007.21.016In order to deal with the huge amounts of data and increasingly stringent response-time requirements, incremental queries processing has recently emerged as a possible solution. Sliding window is one of the most classical windows in dynamic data streams environment. This paper studies aggregation query whith is an important class of continuous operators, and proposes a kind of novel aggregate query algorithms from sliding window over data streams. Many incremental computation approaches and resource sharing techniques in sliding-window aggregations are introduced. Experiments show the feasibility and effectiveness of the approach.
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Computer Engineering. 2007, 33(21): 47-49. https://doi.org/10.3969/j.issn.1000-3428.2007.21.017为了保证实时控制系统的有效运行，除了满足其实时性要求外，可靠性也很重要。该文讨论了实时控制系统的软件可靠性问题，介绍了QNX的高可用性工具，并根据低杂波系统的分布式实时控制需求提出了通用可靠性模型。该模型为低杂波各子系统的开发提供了统一规范，有效保证了系统的可靠性。
QNX；高可用性工具；实时控制系统；可靠性模型
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Computer Engineering. 2007, 33(21): 50-51,5. https://doi.org/10.3969/j.issn.1000-3428.2007.21.018Based on the observation and analysis of occurrence of the type of trivial information inside Web pages, this paper proposes a website topology based Web content refining algorithm. The algorithm partitions the content of web page into five sections, and then prunes the sections which have the same contents with the father node of Web page in website graph representation. Experimental results show the algorithm has a high ratio of precise and recall.
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Computer Engineering. 2007, 33(21): 52-54. https://doi.org/10.3969/j.issn.1000-3428.2007.21.019This paper analyses the similarity between XML schema and DAML and develops a kind of common middle data model which can bridge both of them so that they can be matched by the way of mapping XML schema and DAML to the common data model. By doing so, this method can facilitate adding semantics to Web service automatically, which has been proved by experiments. The result shows that the method is worth being further studied and has a wide application foreground because it is necessary for adding semantics and efficiently to Web service precisely to store a mass of ontologies during the research work of Web service composition based on ontologies.
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Computer Engineering. 2007, 33(21): 55-57. https://doi.org/10.3969/j.issn.1000-3428.2007.21.020Aspect-oriented technology is applied to imprecise computation framework which allows real-time system developers to define and design optional task as aspects. At running time, the optional tasks are dynamically woven or unwoven based on current available resources. A set of tests of weaving and unweaving aspects for the framework are carried out. The tests found that two major factors which influence weaving and unweaving time are the number of advices and the number of targeted methods. Results show the feasibility of using dynamic weaving to achieve imprecise computation in real-time computation. the dynamic weaving has not introduced the time unpredictability into real-time applications.
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Computer Engineering. 2007, 33(21): 58-60. https://doi.org/10.3969/j.issn.1000-3428.2007.21.021Goal elaboration is an important step in requirement modeling method of combining goal with scenarios. This paper puts forward a predication-driven goal elaboration method based on such requirement modeling method. According to the classification of predication, it directs the elaborating process. Compared with traditional elaboration methods, the method is with less dependent on requirement analyzers and more automatic.
requirement engineering; goal; scenario; requirement specification
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Computer Engineering. 2007, 33(21): 61-62,6. https://doi.org/10.3969/j.issn.1000-3428.2007.21.022With ipkg package management program, developers can avoid trivial steps involving cross compilation, quickly build up embedded Linux system, and enable the software to upgrade automatically. This paper introduces the concept of ipkg package management and the package format, and presents the bootstrap process. Taking embedded Web server as an example, the construction of an application system is illustracted. And a package construction process with a Qt graphic system is introduced.
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Computer Engineering. 2007, 33(21): 63-65. https://doi.org/10.3969/j.issn.1000-3428.2007.21.023This paper proposes a method for modeling XML semantic structure with a Petri net. According to the DTD structure of XML, it constructs the Petri net model to describe the XML semantic structure, in which DTD element declaration and attribute declaration are described as some transitions, elements and attributes are described as places, and the path expressions in XML query are described as Tokens in Petri net model. Based on the structure of Petri net model, relational database model is set up to save XML data, and the query of XML is converted to the query of database.
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Computer Engineering. 2007, 33(21): 66-68. https://doi.org/10.3969/j.issn.1000-3428.2007.21.024In process industry, there are many communication protocols, but they have many differences in structure. In order to develop up-layer application, it needs to parse and process these protocols. This paper discusses the protocol in which parsing and processing program can be implemented when the protocol is described with the formalize-description, and the program based on formalize-description is independent of the protocol. This implementation can avoid coding parse and processing program for different protocols separately, and makes the program more flexible and adaptable.
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Computer Engineering. 2007, 33(21): 69-71. https://doi.org/10.3969/j.issn.1000-3428.2007.21.025In a SMP cluster job-scheduling system, most of the well-rounded algorithms such as reservation, backfilling, don’t pay much attention to the overload of system. This paper presents a LT-backfilling algorithm combined with reservation and backfilling. This algorithm focuses on the balance of system’s load and improves the efficiency of balance of system’s load. Based on the algorithm, this paper proposes a job-scheduling system based on XML flow telmplate, in this system, user not only can submit single job, but also can submit a data-relative job flow, the function makes this job-scheduling system more practical.
LT-backfilling; balance of load; job-scheduling; XML; job-flow
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Computer Engineering. 2007, 33(21): 72-74,7. https://doi.org/10.3969/j.issn.1000-3428.2007.21.026This paper proposes a metadata management model for data grid based on dynamic balanceable placement. The model aims to realize a distributed metadata management platform. This platform takes charge of the registry, access and management of metadata. And it implements the mapping from metadata to storage systems. So users can access to metadata resources transparently. In order to meet resource variability in the grid, the model supports a balanceable and scalable metadata placement through an improved data object placement algorithm based on dynamic interval mapping. Its purpose is to improve storage system adaptability.
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Computer Engineering. 2007, 33(21): 75-77. https://doi.org/10.3969/j.issn.1000-3428.2007.21.027Task scheduling in grid environment is to assign the tasks submitted to the grid environment to some resources, according to some rules. A good task scheduling algorithm can improve the usage of the grid environment dramatically. In the grid environment, users hope their task be completed as quickly as possible, but the environment wishes the resources be employed as more as possible. For this situation, the paper proposes the tabu search algorithm which has less time complexity and better performance. The experiment proves it is correct and useful.
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Computer Engineering. 2007, 33(21): 78-80. https://doi.org/10.3969/j.issn.1000-3428.2007.21.028The coverage criteria on data-flow test is achieved by applying trap properties and the temporal logic relationship, the problem of test sequence generation is transformed into the one of finding the counter example in model check, and an automatic generation approach of the test sequences calling methods in class is presented. A searching algorithm to generate automatically the test sequences is designed and implemented with the program model checker called Java PathFinder. The algorithm analysis and experimental results show that the presented algorithm can generate efficiently the test sequences and reduce remarkably the test generation cost.
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Computer Engineering. 2007, 33(21): 81-83,8. https://doi.org/10.3969/j.issn.1000-3428.2007.21.029Through analyzing the limitations of simple network management protocol(SNMP) network management system which adopts the centralized service model, the basic idea of AgnentX frame and the communication model of AgentX, this paper, aims at solving the disadvantages of the AgentX frame that adopts the AgentX protocol to be its communication protocol, proposes an inter-communication mechanism among MasterAgent/SubAgent based on SNMP protocol, and describes a concrete implementation method of how to expand a realized SNMP agent into the MasterAgent/SubAgent frame based on SNMP communication protocol.
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Computer Engineering. 2007, 33(21): 84-86,8. https://doi.org/10.3969/j.issn.1000-3428.2007.21.030Virtual home environment (VHE) becomes a hotspot as a way to provide service in the future heterogeneous network. According to the requirements and features of VHE, this paper proposes a system architecture to realize this concept based on SIP. Then service provision and some mechanisms for supporting VHE in this architecture are introduced. How to realize it based on SIP is discussed.
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Computer Engineering. 2007, 33(21): 87-89. https://doi.org/10.3969/j.issn.1000-3428.2007.21.031An application-level multicast may suffer from poor performance when the deliver tree construction process ignores the topology and link characteristics of the underlying network. This paper uses locating algorithm gradually to direct newcomers to a set of their closest nodes without inducing high overhead. On the basis of this locating process, a topology-aware clustered hierarchical application-level multicast architecture will be designed.
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Computer Engineering. 2007, 33(21): 90-92,9. https://doi.org/10.3969/j.issn.1000-3428.2007.21.032MED is one of DTN’s routing algorithms and MED-PC is a variant in existence, which improves the performance in MED, but requires more preconditions and computing resources. This paper presents a new algorithm called AMED, which avoids the problem of MED-PC as well as keeps its performance.
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Computer Engineering. 2007, 33(21): 93-95,9. https://doi.org/10.3969/j.issn.1000-3428.2007.21.033Ad Hoc network, which can gain wide application in military, disaster relief and research fields, can work by relaying packets through intermediate nodes without the support of fixed infrastructure. Different scenarios in evenly-distributed and random-distributed topology in high-speed mobile ad hoc networks(MANET)are simulated through OPNET. Results based on retransmission times show that both flow and energy constraints can affect energy dissipation but their effects are different.
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Computer Engineering. 2007, 33(21): 96-98. https://doi.org/10.3969/j.issn.1000-3428.2007.21.034Aiming at the low bandwidth utilization of TCP Reno in high speed and delay network, and the shortcoming of HSTCP congestion control algorithm in fairness, this paper proposes an improved congestion control algorithm mHSTCP. The increase of mHSTCP windows uses the HSTCP pattern, when the bandwidth is not used sufficiently. Otherwise the increase of mHSTCP windows uses the Reno pattern. The testing result validates that algorithm mHSTCP improves the fairness between the different data streams evidently in high speed network.
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Computer Engineering. 2007, 33(21): 99-101. https://doi.org/10.3969/j.issn.1000-3428.2007.21.035TCP/IP is the basic protocol in data transfers over networks, and the performance evaluation of TCP/IP over embedded systems has great significations to the study and development of correlative production. In this paper, the data packet sent through the link between PC and embedded systems PXA255 and AT9200 is tested, and all kinds of TCP/IP in embedded systems are analyzed, the optimal data size of server transfers is obtained. Furthermore, the maximum transmission speed of TCP/IP over embedded systems is estimated, and the critical factors and bottlenecks which impact the performance of TCP/IP are found out.
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Computer Engineering. 2007, 33(21): 102-104. https://doi.org/10.3969/j.issn.1000-3428.2007.21.036How to locate efficiently the node that stores desired resource is a core problem in P2P networks and grid computing. Chord is a successful resource location protocol in P2P systems, but its lookup efficiency is lower because finger table has redundant information. An improved and optimal finger structure is presented for removing the shortages of the original chord finger and getting higher location efficiency.
The average query path length can be shortened from (1/2)logN to (1/2)logN-(1/4)logR(N), and lookup efficiency can be heightened obviously.
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Computer Engineering. 2007, 33(21): 105-107,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.037This paper puts forward a roaming mechanism of network user to solve the problem that users register and logon frequently using multiple accounts and passwords in network applications and constructs a relevant roaming model of network user. It imports roaming trust degree, integrated trust degree of peer entity, and trust degree of network user to depict entity roaming ability, and gives calculation algorithm of all the trust degrees. It also discusses roaming technology of network user based on the theory. Analysis and verification imply that the roaming mechanism of network user between peer entities based on trust degree is feasible.
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Computer Engineering. 2007, 33(21): 108-110. https://doi.org/10.3969/j.issn.1000-3428.2007.21.038Buffered crossbar switches are becoming more and more attractive to high performance routers/switches builders than other schemes, as it can achieve throughput, rate and delay guarantees, and distributing scheduling algorithm can be easily implemented. This paper proposes a distributed scheduling algorithm (shorted by DS) supporting differentiated service model (DiffServ) for CICQ switches, which has lower time complexities than previous algorithms. It evaluates the performances of DS through simulation under burst uniform and non-uniform traffic, and compares it with previous algorithms. Simulation results show that DS can provide minimum bandwidth guarantees for EF and AF traffic and fair bandwidth allocation for BE traffic.
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Computer Engineering. 2007, 33(21): 111-112,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.039An improved method of occupying channel time allocation groups based on slotted ALOHA is presented to assign leisure channel time for data flows. This new method can avoid the problems of frame losing or low bandwidth efficiency occurring in the services of VBR and UBR adopting the resource allocation scheme recommended by the criterion of UWB MAC layer. Simulation results show that the scheme can reduce the job failure rate (JFR) and delay jitter, and increase the throughput to a certain extent compared to the scheme suggested by IEEE802.15.3. The transmission with higher QoS can be achieved consequently.
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Computer Engineering. 2007, 33(21): 113-115. https://doi.org/10.3969/j.issn.1000-3428.2007.21.040Time synchronization is a basic and important factor of wireless sensor networks. This protocol adopts sender-receiver mode to transmit time-sync packet, MAC layer time stamping and linear regression methods are used to improve the accuracy of the synchronization. This paper presents the method of cutting the overhead of time-sync, using the next level node degree (NLND), selecting some particular nodes to send packets and other nodes only receive packets passively. The method has lower overhead than flooding broadcast.
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Computer Engineering. 2007, 33(21): 116-118,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.041Wireless sensor networks have been widely used in many important areas. Medium access control (MAC) protocols have a significant effect on the function and performance of sensor networks. This paper summarizes the present design paradigms of the MAC protocol in wireless sensor networks. Then, based on the sensor MAC (SMAC) protocol, and by jointly considering the time division multiple access (TDMA), carrier sense multiple access (CSMA) and the synchronization scheme of the SMAC, a new contention-allowed TDMA based MAC protocol for wireless sensor networks (contention-allowed TDMA based SMAC, C-TDMA-SMAC) is proposed. The simulation results show that, compared with SMAC protocol, this protocol has improved a lot in the delay of packets, energy consumption and the reception rate of the packets.
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Computer Engineering. 2007, 33(21): 119-121. https://doi.org/10.3969/j.issn.1000-3428.2007.21.042Pairwise key issue plays a key role in sensor networks security. An approach on pairwise key establishment based on location awareness is proposed. The algorithm encodes sensor nodes on a hybrid hypercube model with information of nodes’ expected location. Experimental results show that the algorithm has nice features such as higher probability of direct key establishment, reasonable storage cost and good scalability on network scales.
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Computer Engineering. 2007, 33(21): 122-124,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.043After analysing the clustering algorithm and alerts’ prerequisite-consequence attributes, a novel approach of correlating and analysing intrusion alerts based on the combination of both is proposed. Experimental result on DARPA 2000 dataset proves that this approach can pre-process alerts successfully. Compared with the result of using only the prerequisite-consequence alert correlation method, the proposed approach can successfully eliminate three correlation errors, thus improve the efficiency of the correlation.
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Computer Engineering. 2007, 33(21): 125-127. https://doi.org/10.3969/j.issn.1000-3428.2007.21.044This paper analyzes the main threats that instant messaging(IM) confronted, its characteristics, and solutions in existing applications, proposes a suit of strategies to secure IM. This paper introduces the public key infrastructure(PKI) mechanism into IM, adopting techniques such as security socket layer(SSL) and CAPTCHA, and methods such as encryption, signature, signature verification, decryption, CAPTCHA validation and IM message flux monitoring, so as to ensure the security of IM connections and data communications, protect the configurations and notes of IM system, and lighten viruses and worms threats.
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Computer Engineering. 2007, 33(21): 128-129,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.045Radio frequency identification(RFID) technology has been wildly used, but it is lack of security mechanism and it can not protect its data effectively. By analyzing the security and privacy problems in RFID application, this paper affords a secure communication protocol under the limited computation resources in RFID tag to solve these problems. The protocol adopts Hash function to avoid security attacks such as information leak, counterfeit, orientation tail, etc.
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Computer Engineering. 2007, 33(21): 130-133. https://doi.org/10.3969/j.issn.1000-3428.2007.21.046An efficient (t, n) threshold key management scheme for Ad Hoc networks (EECTKM) is presented based on elliptic curve. In the scheme, the certificate authority (CA) is distributed to a group of server nodes. EECTKM can balance the loads of services of server nodes and maintain a certain number of server nodes in network dynamically. It has characteristics of high security, less computational cost, balanced service loads of Server nodes etc. Simulation results show that EECTKM can enhance the efficiency of public key certificate services and has good ability to tolerate failure of server nodes.
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Computer Engineering. 2007, 33(21): 134-136,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.047To solve the problem of lacking risk mitigation part and using security standards synthetically in current information security risk management system(ISRMS), this article expatiates a method to design and implement a new ISRMS. It also brings forward a way to analyze the result of risk assessment and a method to mitigate the risk. Some algorithms for analyzing key factors in risk management are improved. This system covers the short in functions and the interoperability of data in most ISRMS and enhances its application value.
information security; risk management; risk assessment
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Computer Engineering. 2007, 33(21): 137-139. https://doi.org/10.3969/j.issn.1000-3428.2007.21.048This paper analyzes multi-party authorization scheme in electronic business, as well as multi-signature scheme in network communication. Based on hyper-elliptic curves cryptosystem, it presents a hybrid multi-signature scheme that can gain a wide application in computer and wireless communication network. Avoiding security breach, such as information leak and signature forgery scheme, and disadvantage, such as complexity of protocol process, computation expenses for signature certification, it proposes a hybrid multi-signature, and analyzes security and execution efficiency of the scheme. The protocol and algorithm are brief, secure, highly-efficient, which can reduce the system overhead for implementation of software and hardware, so it can be applied to the environment of computer and wireless communication network.
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Computer Engineering. 2007, 33(21): 140-141. https://doi.org/10.3969/j.issn.1000-3428.2007.21.049
A secure problem in a forward-secure proxy signature scheme is pointed out, the proxy signer’s key does not satisfy the forward-security, so that the original scheme is insecure once the adversary gets the proxy signer’s key. The improved scheme proposes an evolution on proxy signer’s key, under the strong RSA assumption, the new scheme is truly forward secure.
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Computer Engineering. 2007, 33(21): 142-143,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.050Based on analyzing data packages on Internet, this paper describes the principle of UltraReach ver6.9, and a software countering blockade, gives a method on detecting and supervising users of these servers from the gateway, proposes a universal method on detecting all kind of the servers. Experimental results show the method is effective.
encrypted proxy; counter blockade software; UltraReach; data package
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Computer Engineering. 2007, 33(21): 144-146. https://doi.org/10.3969/j.issn.1000-3428.2007.21.051Secure information sharing is one of key factors for success of virtual enterprise (VE). This paper analyzes the requirements of a VE access control. A virtual enterprise access control (VEAC) model is proposed to handle resource management and sharing across each participating enterprise, which consists of a project-based access control (PBAC) sub-model to manage public resources and a role-based access control (RBAC) sub-model to manage private resources. The system architecture and constitution of the model are explained. Result implements more secure resource sharing and resource management in VE.
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Computer Engineering. 2007, 33(21): 147-148,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.052Correlation property is the basic characteristic of security protocol. This paper provides a new method based on the correlation property and analyzes the characteristics of correlation of protocols pictured from three aspects, which are the correlation of authentication among principals, the correlation in the message and the correlation among the messages. It proposes concept of the correlationproperty and the construction method of the correlation rules, constructs the protocol description model based on the correlation property, offers a new thought in formal analysis of the protocols.
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Computer Engineering. 2007, 33(21): 149-151. https://doi.org/10.3969/j.issn.1000-3428.2007.21.053For the features of G.723.1 and chaos-based system, this paper introduces an approach that hides the information in chaos-based secure communication system by sending information in the less significant bits of the coded audio data. Experimental result proves that hidden transfer and real-time update of the key makes the system more secure. It can be widely used in places where secure communication is needed to avoid wiretapping and guarantee security.
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Computer Engineering. 2007, 33(21): 152-154. https://doi.org/10.3969/j.issn.1000-3428.2007.21.054Analyses are made on the security threats of present digital fingerprinting schemes, and an asymmetric digital fingerprinting scheme with conditional anonymity based on ring signature is presented. The identity blinding process enables buyers to be conditionally anonymous, and the anonymity can also be revoked if necessary. The probabilistic encryption algorithm in the scheme avoids the relevance between different digital fingerprints generated by the same buyer. The independence of fingerprint security on the hypothesis of an absolutely trustable third party in the scheme prevents coalition attack and generalized fingerprint forgery.
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Computer Engineering. 2007, 33(21): 155-156,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.055In order to prevent the spread of the ill metamorphosed texts in Internet which escapes from the traditional security filtering, a security identification method is presented. The features of metamorphosed characters in the ill texts are analyzed, they are recognized according to the character co-occurrence and the different codes of the characters and symbols, then the extraction algorithm based on association rules is proposed to update the ill feature dictionary. The experiments show that it can improve the current situation that the metamorphosed terms could not be identified using the traditional methods and improve the efficiency and the capability of feature identification as the complement of the topic filtering.
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Computer Engineering. 2007, 33(21): 157-159. https://doi.org/10.3969/j.issn.1000-3428.2007.21.056This paper builds an ontology-based geographic information inquiry system(OGIIS). Through semantic reasoning, geographic information retrieval and ranking, OGIIS can be performed more precisely and intelligently than traditional ones. The semantic relations contained in the geographic information can be explicitly represented and searched.
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Computer Engineering. 2007, 33(21): 160-162,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.057The path planning based on cell decomposition is one of the most popularly studied methods. There is a problem called dimension curse with the dimension of robot freedom increasing, so it disagrees with solving the problem of path planning for high-dimensional robot in complex environment. Therefore, this paper presents an algorithm of path planning based on improved probabilistic cell decomposition. The path constructed by this algorithm is not the best, because probabilistic sampling is introduced in the algorithm. But the efficiency of the algorithm is improved owing to probabilistic sampling, so it is adapted to solve the problem of path planning for the complex environment. Simulation shows improved that this algorithm can quickly find a feasible path.
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Computer Engineering. 2007, 33(21): 163-165. https://doi.org/10.3969/j.issn.1000-3428.2007.21.058Edge extraction in tobacco leaf image is the key step in tobacco leaf detecting and grading using computer technology. In order to extract edge and keep detailed edge information, the original tobacco leaf images obtained by CCD camera are studied. Omni-directional structure element is structured to detect edge according to the grayscale morphology arithmetic. Efficiency of edge detection based on the grayscale morphology erode transform is proved by experimental results.
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Computer Engineering. 2007, 33(21): 166-168,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.059This paper researches on the intelligent information exchanges among Web servers. It discusses how to compose net-union intelligent information exchange model with artificial intelligence and expert system. It also uses extensible markup language(XML) to describe the non-structure data model, which composes the intelligent exchange system. The technology described is feasible and has been proved by some applications.
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Multi-spectral Image and Panchromatic Image Fusion Method Based on Non-negative Matrix FactorizationComputer Engineering. 2007, 33(21): 169-171. https://doi.org/10.3969/j.issn.1000-3428.2007.21.060A new method based on non-negative matrix factorization (NMF) technique is presented for multi-spectral image and panchromatic image fusion. Low resolution multi-spectral image and high resolution panchromatic image are taken as source data in NMF analysis , from which feature bases containing global features of the original images can be extracted. The first feature base is replaced by the adjusted panchromatic image, which is histogram matched to the raw first feature base. Inverse transform (reconstruction) is performed and the fusion image with higher spatial resolution and spectral component is obtained. Visual results and statistical indexes demonstrate the advantage of the proposed NMF-based image fusion method compared to common fusion approaches.
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Computer Engineering. 2007, 33(21): 172-174. https://doi.org/10.3969/j.issn.1000-3428.2007.21.061Aiming at some problems of too much training time and weight adjustment over fitting in face detection by using AdaBoost. This paper proposes enhanced dual-AdaBoost algorithm based on feature-value-division and dual-threshold, which makes training faster and better. It gives a method to get dual-threshold, and presents the improved mode of weight adjustment. Experimental results on MIT-CBCL training data set illustrate that the dual-AdaBoost makes training process converge quickly, and the training time is as 1/50 as before. Experimental results on MIT+CMU with the detectors show that the detection speed and precision under the dual-threshold are better than single-threshold method.
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Computer Engineering. 2007, 33(21): 175-178. https://doi.org/10.3969/j.issn.1000-3428.2007.21.062A multi-objective optimization based on suitable-distribution particle swarm (SDPS) is discussed. There are simple rules and quick convergence speed for SDPS. Also, it can ensure the final solutions more dispersive and symmetrical. A new method is proposed to update the external memory and fix the fit-sharing radius. In order to compare with other algorithms, the proposed algorithm is used to solve some well-known multi-objective functions. It is proved that the proposed algorithm is able to find the solutions which are much more exact and efficient convergence to the true Pareto front and much more well-proportioned distribution over the Pareto front.
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Computer Engineering. 2007, 33(21): 179-180,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.063In view of the problem of the conventional method for unsharp masking algorithm for image enhancement based on wavelet transform that the enhancement of edges whose contrast is same but angles are different is greatly different, a new method for unsharp masking algorithm for image enhancement based on wavelet transform is proposed. The original image is decomposed into wavelet, is based on angles of wavelet coefficients, wavelet coefficients are self-adaptively processed. The image of enhancement is obtained via the inverse wavelet transform. The experimental result demonstrates that the difference of enhancement of edges whose contrast is same but angles are different in the new method is greatly less than that in the conventional method.
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Computer Engineering. 2007, 33(21): 181-182,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.064Gait recognition is a new technique of recognition based on biologic characteristics, which aims at recognizing the human’s identity based on their walk styles. This paper analyses the arithmetic of gait recognition and expatiates the motion segment, feature extraction and pattern recognition with some test pictures. The two methods based on the model and based on the characteristics are compared and analyzed.
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Computer Engineering. 2007, 33(21): 183-185. https://doi.org/10.3969/j.issn.1000-3428.2007.21.065This paper presents a distributed CBR design system framework, in which a share ontology is created in ontology server and domain knowledge can be represented flexibly in case bases under the constraint and guidance of the share ontology. Because every case base is created with ontological commitment to share ontology, knowledge integration can be achieved effectively. This system is constructed by using Web service technology and system integration in heterogeneous environment can be achieved. This framework is open and extensible.
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Computer Engineering. 2007, 33(21): 186-188. https://doi.org/10.3969/j.issn.1000-3428.2007.21.066Ontology is important for information integration and share and it is intelligent business in the industry of import and export. This paper presents an ontology and its function, characteristics, representation with requirements of import and export applications. A formal reasoning solution and mechanism are illustrated for the ontology-based reasoner. A semantic query language is explored to implement the proposed reasoner.
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Computer Engineering. 2007, 33(21): 189-191. https://doi.org/10.3969/j.issn.1000-3428.2007.21.067The problem of minimum weight triangulation (MWT) is one of the most important issues in computer vision. This paper proposes an adaptive immune genetic algorithm(AIGA) to solve the problem. Based on the analysis of immune algorithm(IA) properties, the convergence speed of AIGA is faster than IA and the global search capability is improved with a self-adaptive adjustment method to the vaccine pool together with selected vaccination. According to the practical MWT, the strategies of updating and injecting a vaccine for the problem are both provided in the paper. Simulation results show that the algorithm performs better than IA in terms of quality of MWT, especially for the large scale of point cluster, and has good practical value.
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Computer Engineering. 2007, 33(21): 192-193,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.068Chaos optimization algorithm(COA) is put forward to solve value optimization problems, which can find the best solution efficiently. However, it is difficult for COA to solve combinational optimization problems. To solve the problem, this paper presents a method to solve combinational optimization problem based on COA. An initial solution is produced, and a new solution is produced by chaos variables or by disturbing initial solution based on chaos variables. Based on the method, the paper solves two typical combinational optimization problems(0/1 knapsack problem and TSP problem). And the result of simulation shows the validity of the algorithm.
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Computer Engineering. 2007, 33(21): 194-196. https://doi.org/10.3969/j.issn.1000-3428.2007.21.069This paper proposes an algorithm of infrared bicolor target recognition, in which 2D Fourier-wavelet transform is applied to extract the features of image, and the Fourier-wavelet description for the object recognition is regarded as vector characteristics, characterized with invariancy to translations, scaling and rotation. It improves the rate of target recognition by using D-S theory and netural network classifier. Experimental results show this algorithm can identify the aircraft and the warship objects effectively.
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Computer Engineering. 2007, 33(21): 197-198,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.070In allusion to the supposed precondition in ant colony algorithm of infinite speed of ants and synchronous updating of pheromone, this paper proposes an algorithm for resource search based on pheromone release of intelligent ant colony. The algorithm takes finite speed of ants as the precondition and adopts the pheromone-oriented renewed rules to adjust the pheromone strength of each ant so that it can indirectly change the cooperative means among ants. The algorithm is more obedient to the actual road-search process of ant colony and possesses the better ability of all-sided search. For the grid GIS resource of enormous search-initialized data amount, the algorithm holds higher efficiency than the basal ant colony algorithm and other algorithms of resource search.
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Computer Engineering. 2007, 33(21): 199-201. https://doi.org/10.3969/j.issn.1000-3428.2007.21.071Extracting entity relation is benifit to understand the meaning of text, so as to increase correctness of searching. This paper researches on extracting Chinese entity relation templates from text collections, and puts forward a kind of bootstrapping method called STG. This method makes use of sequence matching technique in bioinformatics to generate semantic templates within context of Chinese entities. A new model of evaluation is presented to select better templates while tuples are expanded to obtain high quality in the next iteration of training. Experimental results show that the templates created by STG not only can cover a large number of tuples, but also can reach 99% accuracy.
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Computer Engineering. 2007, 33(21): 202-204. https://doi.org/10.3969/j.issn.1000-3428.2007.21.072Partner selection and optimization are critical issues in virtual enterprise formation. According to the relationship among tasks that virtual enterprises face, the problems of partner selection for a virtual enterprise are classified into three types: series connection, parallel connection and compound connection. In the light of the problem’s conditions, a multi-objective decision making model is constructed. The optimization process of the model is made up of filtering candidate enterprises and determining optimal plan. Simulation results demonstrate validity of the algorithm.
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Computer Engineering. 2007, 33(21): 205-206,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.073This paper proposes a novel algorithm for target detection, which is based on motion and region information. A fast optical flow estimation method and a region growing and merging technique are utilized to estimate the motion vector and the region information of the target respectively. Unlike other algorithms the method makes good use of the motion and region information, as a result the computational complexity of optical flow estimation and region segmentation method decreases distinctly. Simulation results show the algorithm achieves a good performance in most complex outdoor environments.
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Computer Engineering. 2007, 33(21): 207-209. https://doi.org/10.3969/j.issn.1000-3428.2007.21.074At present, how to extract information reliably is still a difficult, unsolved problem. Based on ontology entity relation match, this paper presents an information extraction new algorithm based on ontology entity relation match, which presents the object document to special ontology of semantic Web, analyzes and processes the ontology by machine learning principle. Experimental results show that relation match algorithm based on ontology have an advantage over other four approaches.
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Computer Engineering. 2007, 33(21): 210-212. https://doi.org/10.3969/j.issn.1000-3428.2007.21.075Application layer multicast does not need the support of network layer equipment which is suitable to be used in streaming media systems. Based on the framework of existing live streaming media systems using unicast paths, application-layer-multicast based live streaming media system is proposed by building application layer multicast server, giving client software the ability to transfer received media streams, and designing specific multicast protocol for media streams. A demon system is developed which shows the proposed solution can provide stable and acceptable quality service. Compared to the systems using unicast paths, the demon system can serve much more users.
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Computer Engineering. 2007, 33(21): 213-215,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.076It can not give satisfying results when applying error concealment to intra frames of H.264 by simply using weighted pixel value averaging(WPVA) or directional interpolation. A directional entropy based adaptive spatial interpolation algorithm is presented. The algorithm adaptively switches between WPVA and an improved directional interpolation algorithm is also presented here according to edge information around lost area in a frame. The directional interpolation algorithm presented here use a ‘two loop method’ to give more precise estimate of edges in the lost area compared to other directional interpolation algorithm. Experimental results show that the algorithm can achieve good directional interpolation concealment results, and can avoid fake edges.
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Computer Engineering. 2007, 33(21): 219-221,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.078Monte Carlo is a good choice to compute the problem of global illumination in the field of realistic image synthesis. However, the image produced by a Monte Carlo-based global illumination algorithm is noisy when not using a large enough number of samples. Adaptive sampling is an attractive means to reduce these noises. This paper introduces a new measure based on entropy for adaptive sampling. Experimental results show that the method can perform better than classic ones.
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Computer Engineering. 2007, 33(21): 222-225. https://doi.org/10.3969/j.issn.1000-3428.2007.21.079The multimedia monitor system over network for its capture and encoding ability for real-time information has good application. But the implementation of the real-time multimedia encoding system is hard to realize. A network aware solution is proposed. The approach has earned a good performance in the experiment, and has the reference mean to the similar systems as well.
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Computer Engineering. 2007, 33(21): 226-228. https://doi.org/10.3969/j.issn.1000-3428.2007.21.080Isosurfaces are common visualization measures in many fields. Marching cubes algorithm is an effective way to render the object surfaces. Octree is an important way to describe 3D objects. By using the octree, a surface reconstruction algorithm based on space segmentation is presented. The space is divided along X, Y, and Z respectively. The nodes of the tree are less than eight. The number of meshes is less than octree. Then by means of marching cube algorithm, triangles are produced. By trilinear method, the triangles are dealt with smoothly. The surface of the object is reconstructed using C++ and OpenGL. In this way, the quality of the algorithm is good.
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Computer Engineering. 2007, 33(21): 229-231. https://doi.org/10.3969/j.issn.1000-3428.2007.21.081This paper proposes an efficient mesh smoothing method. The method can smooth mesh fast, while preserving features. It smoothes the normal of every triangle in the mesh and ges the normal of every point in the mesh after normal smoothing, improves the moving direction of the vertices according to the distances between current vertex and adjacent vertices, and the angles between the normal of current vertex and of adjacent vertices, gets the weight of each vertex in the iteration using Gaussian. It provides a series of examples to demonstrate the effectiveness of the method presented with less iteration and volume shrinkage.
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Computer Engineering. 2007, 33(21): 232-234. https://doi.org/10.3969/j.issn.1000-3428.2007.21.082This paper presents a new urban intelligent traffic management command and dispatch system based on WebGIS. Integrating several traffic management sub-systems based on WebGIS, this system provides the traffic managers with intelligent management, command and dispatch. The concept, characteristics and advantages of WebGIS applied in urban traffic management are introduced and the system architecture of the system is proposed. The data exchange based on XML and the database is introduced. It also analyses the system’s main function, technology characteristics and the method of implementation.
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Computer Engineering. 2007, 33(21): 235-236. https://doi.org/10.3969/j.issn.1000-3428.2007.21.083It is an important approach to improve the quality of requirements through process improvement of requirements engineering. A process reference model of requirements engineering is established based on CMMI. The model defines four capability levels and about 40 practices of requirements process. The appraisal method of requirements process capability and the policies of process improvement are explored.
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Computer Engineering. 2007, 33(21): 237-239. https://doi.org/10.3969/j.issn.1000-3428.2007.21.084Principle of reading and writing of register file of digital signal processor based on VelociTI architecture is studied and one design method is proposed. Reading of single operand double precision floating point instructions is accomplished by using two 32 bits data path in one pipeline cycle. For two-operand double precision floating point instructions, decode unit is locked until all operands are accessed. Writing control signal vector is adopted for writing. Double precision floating point data based on IEEE754 standard can be accessed with 32 bits data path by using this method. The correctness is conformed by simulation results.
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Computer Engineering. 2007, 33(21): 240-242,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.085Based on a test and control platform with CPU LPC2292(ARM7)and RTOS with Nucleus PLUS, this paper analyses and expatiates design and realization method of a USB host module based on USB host controlling chip ISP1161A1, including the design scheme of USB host function module, the frames of USB host hardware circuit, the design method of embedded USB host driver procedure, and the realization mode and operation process of this scheme. According to the primary and correlated function of host driver procedure, aiming at the key problems of general USB device driver procedure interface and lower layer data management of host controller driver procedure, the settlement scheme key data structure and concise remarks are given.
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Computer Engineering. 2007, 33(21): 243-245,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.086Aiming at the needs of online performance monitoring and fault diagnosis, data acquisition system for internal-combustion engine is designed. The whole system is composed of a portable computer, a multi-channel data acquisition card——PCL-818HD, signal conditioning circuits and some related sensors. Also, programming method of data acquisition program based on VB and DLL techniques under Windows environment is introduced. The high speed data acquisition for startup signal, oil signal and vibration signal of internal-combustion engine is realized, which provides a basis for the analysis of internal-combustion engine performance condition and fault diagnosis.
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Computer Engineering. 2007, 33(21): 246-248. https://doi.org/10.3969/j.issn.1000-3428.2007.21.087A five-tier remote supervisory control system architecture is designed for pump station in oil field.. In this architecture, run time data are acquired by sensors and programmable logic controllers (PLC) and transferred to CES via Profibus. Production process of pump station is automatically supervised in real time by CES. Data between CES and database server are exchanged by OPC (OLE for process control) server. The Web server for remote querying and report application are constructed on the database server. A case study is provided and a remote supervisory control system for a pump station is implemented based on the above architecture. The response time of the database is less than two seconds, which can meet the real-time controlling requirement for pump station.
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Computer Engineering. 2007, 33(21): 249-251. https://doi.org/10.3969/j.issn.1000-3428.2007.21.088According to the important roles of the target recognition in navy operation, the design scheme of the passive sonar target recognition compositive simulation system is researched and presented in this paper. The main function and overall structure of the system are designed. The modules of the system mainly include sonar detecting part, ship noise replay part, target recognition part, target characteristics database and synthetic display part. The simulation software and models are established. The results of engineering experiments show that the scheme is reasonable and effective.
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Computer Engineering. 2007, 33(21): 252-254. https://doi.org/10.3969/j.issn.1000-3428.2007.21.089Based on the probes into the normal function and structure of short message service (SMS) platform, a SMS platform oriented to intelligent public transport travel service is proposed in this paper, consists of the normal need definition of public transport travel, the protocol of need short message and the working mechanism of the platform. Then the key technologies such as data collection, public transport transfer algorithm and fuzzy demand satisfaction are discussed. This platform has been put into practice and has gained good effect.
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Computer Engineering. 2007, 33(21): 255-256. https://doi.org/10.3969/j.issn.1000-3428.2007.21.090Presently a low voltage disconnect (LVD) can only fit a single power system and drive a given rated voltage contactor, which limits the use of LVD. The fact that the change of LVD’s supply voltage influences the coil voltage of the contactor directly causes the misoperation of the LVD. This paper researches on the voltage self-adaptation of LVD and proposes a progressive scheme for driving contactor with PWM fuzzy controlled. A multi-voltage self-adaptive LVD based on PIC is developed. The result of the experiment shows that the scheme improves the self-adaptation and the stability of the system greatly, and protects the contactor.
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Computer Engineering. 2007, 33(21): 257-258,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.091According to American military’s layout of global information grid, it is necessary to integrate tactical data link into GIG architecture. Based on the core of GIG system, this paper advances a tactical data link reference model, which can integrate TDL into GIG architecture seamlessly. It illustrates the interaction of each layer with link-16, provides experience and lessons for construction of our military’s incorporate tactical data link.
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Computer Engineering. 2007, 33(21): 259-261. https://doi.org/10.3969/j.issn.1000-3428.2007.21.092Aimming at the issue of designing campus network with multiple outputs, this paper proposes centralized, distributed and addressing-mode based distributed routing control model by categorizing customers in multiple outputs network as single direction, double direction and partly double direction addressing mode. In an example, coexistence way of private IP and public IP and implementation method of replacing routing logic with physical divaricating structure are analyzed. It provides universal reference model for designing campus network with multiple outputs.
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Computer Engineering. 2007, 33(21): 262-264. https://doi.org/10.3969/j.issn.1000-3428.2007.21.093Grid is an integrated environment of resources and computing, which is currently the research focus in the information area. Simulation grid is the collaborative M & S (modeling and simulation) environment based on grid, which helps to further and widen share of the simulation software/hardware resources and become the important technologies and tools for the M & S of complex systems. This paper brings forward the six-layer architecture of simulation grid prototype system based on grid and Web technology. And the research and realization of the corresponding key technologies such as simulation grid supporting platform technology, simulation resources grid-enabled technology, simulation grid service management technology and the application portal technology are introduced.
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Computer Engineering. 2007, 33(21): 265-267. https://doi.org/10.3969/j.issn.1000-3428.2007.21.094An algorithm combines the auto-correlation and inter-correlation to estimate the time delay of stabilized signal in different noises, based on the analysis of many generalized correlations. Theory analysis and simulation prove that the second correlation can obtain higher precision than the generalized correlation in lower SNR.
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Computer Engineering. 2007, 33(21): 268-269,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.095The traditional detecting line like photoelectricity detect-line is often affected by the environment light and the situation around. This paper provides a new way to detect the line applied in the self-determination detect-line robot. The system includes target-image collecting module, image processing module, drive motor module and so on. The collecting principle of target image of the linear CCD, the principle of the generation for the driver pulse, the hardware and software design of the S3C44B0X and the operation of other parts are explained. Experiments show that the system has good real-time capability, stabilization and high control accuracy.
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Computer Engineering. 2007, 33(21): 270-272. https://doi.org/10.3969/j.issn.1000-3428.2007.21.096Reuse-based software technology reduces time and expenses for software development, enhances the flexibility, maintainability and reliability, and shortens the development cycle of software. This paper studies software reuse technology, proposes a software reuse idea in stock managing domain. Based on the spare parts stock managment system produced by Qingdao MESNAC Co., Ltd., building process of the software is described. Experimental results show the technology is effective.
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Computer Engineering. 2007, 33(21): 273-275. https://doi.org/10.3969/j.issn.1000-3428.2007.21.097The widespread usages of embedded applications have led to a new level of functional variety and complexity in embedded hardware. Because of the lack of a common framework for developing device drivers, implementing or porting drivers for real-time embedded systems is a difficult task for developers. This paper presents a common framework for driver development based on real-time operating systems, various devices and bus interfaces will be supported with ease under this scheme. A technique of implementing a high speed interrupt system required to meet the hard timing constraint and high reliability of real-time systems is also explained.
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Computer Engineering. 2007, 33(21): 276-277,. https://doi.org/10.3969/j.issn.1000-3428.2007.21.098This document describes the points in design and implement of OBS. The system process flow, architecture and data gather interface are designed based on analysis of business model. The Web applications are implemented with JSF, entity Bean, JPA and annotation, meanwhile the external interface communicates with other systems through Web Service and the content format of messages and data file is XML. OBS architecture is clear and tasy to be extended with the new characteristics of Java EE 5.
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Computer Engineering. 2007, 33(21): 278-280. https://doi.org/10.3969/j.issn.1000-3428.2007.21.099Aiming at the requirement of software such as high fault-tolerance and high reliability, this paper presents a framework for software development tool based on MDA, and describes how to extend the support to fault-tolerant(FT) software development. This tool can reduce the problems of the description of software fault-tolerance properties, and increases the efficiency of software development.
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Computer Engineering. 2007, 33(21): 281-282. https://doi.org/10.3969/j.issn.1000-3428.2007.21.100This paper studies the prediction technology of bus arrival time. After building the model of public transport network, the road traffic situation and corresponding traveling time are speculated according to dynamic data collected by GPS vehicle terminals, and then the bus arrival time is predicted. Different kinds of errors are analyzed. The accuracy of this method is more than 80% within the range of two minutes error permission, which can generally meet the requirement of prediction for bus arrival time.
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Computer Engineering. 2007, 33(21): 283-285. https://doi.org/10.3969/j.issn.1000-3428.2007.21.101The integration between COMGIS and model is one of hotspots of current GIS research. Groundwater resources assessment system based on COM and ArcObjects is the embodiment of GIS modeling technique applied to geo-simulation research. This paper introduces COM and COMGIS’s principle, mode of software development is discussed under ArcGIS’s open development environment, the system is successfully constructed with VB.net and COM technology. Theory of integration between COMGIS and groundwater resources assessment model is discussed by the specification of the purpose of system design, the framework of system, data construction, and function design.
2024
Volume 50 No 4
Volume 50 No 4
(Started in 1975, Monthly)
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428