20 July 2009, Volume 35 Issue 14
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Computer Engineering. 2009, 35(14): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2009.14.001This paper researches the arithmetic in GF(3m), the arithmetic on elliptic curve over GF(3m) and Elliptic Curve Cryptography(ECC) protocol. It designs and implements an EC cryptographic algorithm library, tests and analyzes GF(3m)-ECC algorithms. Results show that GF(3m)-ECC algorithms can provide the same performance as ECC algorithms on GF(2m) and GF(p), and can be applied into ECC security protocols design.
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Computer Engineering. 2009, 35(14): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2009.14.002Subspace clustering is an important part and research hotspot in clustering research, which resolves the problem of clustering sparse data in high dimensional data environment. A subspace clustering algorithm based on k most similar clustering is presented. This algorithm holds the k most similar clustering by the similarity of the clusters, discovers the different subspace through the different local density threshold, ascertains the subspace search direction by the k most similar clustering and clusters both continuous data and categorical data. The high dimensional data can be effectively clustered in this algorithm. Experimental results show that this algorithm is more effective in clustering than CLIQUE and SUBCLU.
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Computer Engineering. 2009, 35(14): 7-9. https://doi.org/10.3969/j.issn.1000-3428.2009.14.003In order to research the requirements of energy consumption in Wireless Sensor Networks(WSNs), a Media Access Control(MAC) protocol in WSNs is proposed, which abstracts the different application scenes. Simulation platform of WSNs based on OPNET is set up. The performances of energy consumption and timelag in different application scenes are tested. Experimental results show that all kinds of MAC protocols can provide better performances in each application scene, but all the performances are not best.
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Computer Engineering. 2009, 35(14): 10-12. https://doi.org/10.3969/j.issn.1000-3428.2009.14.004The current Remote Sensing(RS) image interpretation systems can not meet the given actual demand for tiny objects and the extraction applicability to different objects of interests. This paper designs and implements a new interactive RS image interpretation system scheme based on GrabCut algorithm. An integrative database of all the interested objects is built, which supplies references to their respective Regions Of Interests’(ROI) determination. Different objects are interactively extracted preparing for the following recognition. An experiment takes planes as an example, the experimental results show that the scheme is independent of particular object characteristics, and it provides a good support for the RS image interpretation work.
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Computer Engineering. 2009, 35(14): 13-15. https://doi.org/10.3969/j.issn.1000-3428.2009.14.005Based on communication sequence and considering the influence of uncertain short delay, this paper models the Networked Control System(NCS) with communication constraints as a discrete switching system with uncertainty, which integrates information scheduling and control. Based on the switching system theory and piecewise Lyapunov function method, the condition for asymptotic stability of system with periodical information scheduling is derived in the form of matrix inequalities, and a state feedback controller design method is provided. Simulation results validate the validity of this method.
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Computer Engineering. 2009, 35(14): 16-19. https://doi.org/10.3969/j.issn.1000-3428.2009.14.006Aiming at the critical areas coverage NP-complete problem in Wireless Sensor Networks(WSN), this paper proposes a Critical Areas Coverage Heuristic Optimization(CACHO) algorithm. Based on unit disk graph communication model, this algorithm describes the problem of critical areas coverage, and assigns different weight for critical grid points and common grid points to create graph of sensing filed and terminal set and form critical areas coverage grids set with minimal number. Comparison results with an existed coverage algorithm named NPCC prove that CACHO algorithm deploys fewer sensors and can fully cover critical areas.
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Computer Engineering. 2009, 35(14): 20-21. https://doi.org/10.3969/j.issn.1000-3428.2009.14.007A single event upset may happen in the task stack and spoile the task context, so the on-board software may be affected in the way of getting wrong results, running to undefined point or becoming collapsed. Aiming at this problem, this paper improves the embedded kernel µC/OS-II and implements protection mechanism for task context. A test is given, which proves the protection mechanism for task context can effectively get rid of the effect on task stack caused by a single event.
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Computer Engineering. 2009, 35(14): 22-24. https://doi.org/10.3969/j.issn.1000-3428.2009.14.008By exploiting vector-class characteristics of color pixels, this paper proposes to use an improved Progressive Fast Impulsive Vector Filter(PFIVF) to replace the Gauss filter within the framework of Canny detector. The switching scheme of the PFIVF is constructed on the multi-level noise detection mechanism by using Peer Group technique and edge detection method, and makes it possible to preserve edge details of color image while suppressing noise. Experimental results show that the performance of the edge detector is robust to high-level impulsive noise.
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Computer Engineering. 2009, 35(14): 25-27. https://doi.org/10.3969/j.issn.1000-3428.2009.14.009A fine synchronization method for Orthogonal Frequency Division Multiplexing(OFDM) based on Channel Impulse Response (CIR) is proposed. CIR is estimated by Least Square(LS) channel with suppressing the effect of energy leakage under non-ideal synchronization, and the estimation result is timed. The window function based on CIR is also introduced. Simulation experimental results show this method can overcome the demerits of time lags for traditional relevant methods, and achieve higher estimation accuracy.
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Computer Engineering. 2009, 35(14): 28-29. https://doi.org/10.3969/j.issn.1000-3428.2009.14.010Aiming at the problem as low robust watermark capacity and week imperceptibility of watermark images in multi-channel watermark scheme, this paper proposes a multi-channel image digital watermark scheme based on zero reference watermark. In this scheme, zero reference watermark is defined based on quantization function. During watermark detection, it extracts reference watermarks, computes distortion rates of watermark channels by comparing zero reference watermarks and the extracted reference watermarks, and computes robust watermarks according to the distortion rates. Experimental results show that this scheme improves the accuracy of extracted watermarks without losing its imperceptibility.
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Computer Engineering. 2009, 35(14): 30-31. https://doi.org/10.3969/j.issn.1000-3428.2009.14.011This paper proposes and builds a load-aware structured Peer to Peer(P2P) protocol——LaChord. LaChord uses a reactive load-aware routing state maintenance strategy and a load-aware routing algorithm, the former increases the probability of the light loaded nodes as the intermediate nodes forwarding messages through improving the in-degree of the light loaded nodes, and the latter makes messages routed bias to light loaded nodes with provable query performance. Simulation results indicate load-aware protocols that implement reactive load-aware routing state maintenance algorithm and load-aware routing algorithm have a better load balance than the traditional P2P protocols, so load-aware algorithms can improve the scalability of systems.
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Computer Engineering. 2009, 35(14): 32-34. https://doi.org/10.3969/j.issn.1000-3428.2009.14.012While HTML tables are widely applied for Web, XML is widely accepted as a standard format to process and manage information. In order to utilize and manage XML, the HTML tables should be transformed into XML representations. This paper presents an efficient method for the process, which consists of two phases, such as area segmentation and structure analysis. The area segmentation cleans up tables and segments them into attribute and value areas by checking visual and semantic coherency. The hierarchical structure between attribute and value areas is analyzed and transformed into an XML representation using a proposed table model. Experimental results with more than 300 HTML tables show that the proposed method performs better than conventional methods, resulting in an average accuracy of 86.7%.
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Computer Engineering. 2009, 35(14): 35-37. https://doi.org/10.3969/j.issn.1000-3428.2009.14.013Concurrency control is the most important mechanism of improving the transaction capability of database system. And it is also a difficulty in the field of Native XML database. Some kinds of Native XML database operations based on the simplified Xpath data model are proposed. On the basis of this, an Xpath-based locking protocol is put forward and the schedule within the locking protocol mentioned above is proved to be serializability. Some detailed discussion is given to analyze the capability of concurrency for the protocol.
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Computer Engineering. 2009, 35(14): 38-40. https://doi.org/10.3969/j.issn.1000-3428.2009.14.014On the research of quantitative association rules mining in database which contains quantitative attributes, the combination of the quantitative attributes and the intervals associated leads to an unmanageably highly sized itemsets and association rule sets which constitute a hamper toward the efficiency of the mining algorithm. The mutual information entropy of the attributes is studied here, and algorithm BMIQAR which can find the frequent itemsets and association rules from the attributes sets with strong information relationship is designed. The experiments show that due to the prune on the attributes, the research space decreases sharply, so the mining efficiency is improved greatly, and the acquired association rules are high confidence ones.
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Computer Engineering. 2009, 35(14): 41-44. https://doi.org/10.3969/j.issn.1000-3428.2009.14.015Aiming at the security problem of E-government application, this paper proposes the government meta-organization model for extended Privilege Management Infrastructure(PMI) and the relevant mathematical description. The application development platform is constructed by using this model, and is applied to the practical project establishment. Application results show that this model can adapt to E-government applications security needs in changing environment, realize authorization management, and has high promotional value.
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Computer Engineering. 2009, 35(14): 45-48. https://doi.org/10.3969/j.issn.1000-3428.2009.14.016This paper proposes a novel query expansion method using Local Context Analysis(LCA) based concept tree pruning. It extracts the suggested terms from initial documents which are retrieved for the original query by LCA method, and uses these terms to prune the concept tree built by lexical database, to add new terms, and to recalculate the weight of expanding terms. Experiments show that the combined expansion yields significant improvements over existing algorithms under the same experimental condition.
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Computer Engineering. 2009, 35(14): 49-51. https://doi.org/10.3969/j.issn.1000-3428.2009.14.017There is only a little research on incrementally cluster temporal data streams. This paper focuses on the problem of clustering temporal data streams based on the sliding window. Temporal Multiple-dimension Subspace α-Cluster(TMSC) is adopted. It consists of data streams, whose distance is less than 2α, and must contain a number of streams which are predefined. The result of the clustering is updated through time evolving. Sliding window mechanism is adopted to realize it. The earliest data is removed, and the new coming data is added. Stock data is used to test the algorithm, and the result is quite well.
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Computer Engineering. 2009, 35(14): 52-54. https://doi.org/10.3969/j.issn.1000-3428.2009.14.018Recovery-Oriented Computing(ROC) improves system availability by repairing the system as soon as possible, instead of avoiding failure. This paper studies ROC techniques, gives its application in cluster system, proposes the method of Recursive Restartability(RR) based on node group and Undo recovery model based on Checkpoint to improve system availability. It evaluates the improvement effect of the methods.
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Computer Engineering. 2009, 35(14): 55-57. https://doi.org/10.3969/j.issn.1000-3428.2009.14.019In order to build cross-organization distributed Workflow Management System(WfMS) cater for the requirements of modern enterprise information’s distribution, autonomy and heterogeneity, this paper proposes a new distributed workflow process model. Based on the model, it utilizes Web services and JMX to build a prototype system——CODWfMS, which can realize the nested sub-process interoperability and parallel synchronized interoperability etc, between WfMSs of cross-organizations, it realizes the really platform independance and language independance, and provides some solutions for relevant issues.
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Computer Engineering. 2009, 35(14): 58-59. https://doi.org/10.3969/j.issn.1000-3428.2009.14.020When using false-positive approach to mine Frequent Traversal Sequence(FTS) in Web clickstreams, it utilizes relaxation ratio ρ to control memory consumption and precision of mining result. However, such approaches may lead to a conflict between precision and memory consumption because of using ρ. This paper proposes FTS-Stream algorithm based on false-negative approach and time-sensitive sliding window to solve the problem. FTS-Stream uses two bounds to constrain ρ, and adopts a Weighted Harmonic Average(WHA) of the two bounds to replace ρ. Experiments show that the algorithm performs better than many established FTS mining methods.
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Computer Engineering. 2009, 35(14): 60-62. https://doi.org/10.3969/j.issn.1000-3428.2009.14.021Aiming at the problem of limited application scope and incapable extension of currently measurement frameworks for software testability, a new measurement framework is proposed. Its structure is derived from the analysis of the software testability concept by analytical hierarchy process. An extension method is summarized and the testability characters and affecting factors are appended to the framework to measure the software testability. The stability of the framework ensures the software testability in the same process and calculation method. The expansibility keeps the framework evolved with the software technology development. They both make the framework all-purpose.
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Computer Engineering. 2009, 35(14): 63-65. https://doi.org/10.3969/j.issn.1000-3428.2009.14.022In order to meet the wide-area distributed requirement of 3D solid modeling and overcome the shortcoming in openness and scalability of traditional CAD software, this paper proposes a solid modeling framework based on Web services. It decreases the expense of transferring large amount data through the Internet, and builds a hybrid solid model. Based on Web service, a distributed solid modeling framework is outlined, and a software system is built based on Open CASCADE. It is proved that the approach can provide an effective way to realize distributed solid modeling.
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Computer Engineering. 2009, 35(14): 66-68. https://doi.org/10.3969/j.issn.1000-3428.2009.14.023Aiming at the functional limitations of the ArcObjects component, this paper proposes a development method with custom-made component to extend its application functions, displays the design and implementation method of GIS application software based on ArcObjects component and gives the detail demonstration of custom-made component design and realization through application programming examples. The widely use of the developed component in the GIS applications shows that the development method with custom-made component further enhances the reuse quality of code, accelerates the development speed of the application software.
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Computer Engineering. 2009, 35(14): 69-71. https://doi.org/10.3969/j.issn.1000-3428.2009.14.024Concept name is important in the process of ontology mapping. This paper proposes a modified concept name similarity algorithm against polysemy of concept name in the process of concept name similarity. Combined with comment and gloss of synset by Latent Semantic Analysis(LSA), it determines the corresponding synset of concept in the Wordnet. So it improves the accuracy of similarity to a certain extent. Experimental result shows that the algorithm is viable.
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Computer Engineering. 2009, 35(14): 72-74. https://doi.org/10.3969/j.issn.1000-3428.2009.14.025The smallest cache utility algorithm based on popularity and visited times in future, SCU-PFUT, is proposed. In addition, it considers bytes benefit of stream media file and the size of file block, so it is more reasonable when move data block out of cache. It not only avoids the problem of the stream media file being continuously replaced, but also has better performance in enhancing cache hit rate, byte hit rate and space use rate than LRU, LFU and SCU-2.
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Computer Engineering. 2009, 35(14): 75-77. https://doi.org/10.3969/j.issn.1000-3428.2009.14.026This paper introduces a crawling algorithm based on Web site structure and page structure and presents a new algorithm based on navigate tree. This algorithm analyzes the structure similarity of the pages crawled with the ordered labeled rooted tree based on the key HTML tags by the restricted tree edit distance algorithm and restricts the pages for the wrapper crawling by a navigate tree based on the URL similarity and the topology of the Web site. The efficiency and accuracy are improved.
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Computer Engineering. 2009, 35(14): 78-80. https://doi.org/10.3969/j.issn.1000-3428.2009.14.027A re-engineering framework of legacy system based on distributed environment of J2EE partition is given. Improved level-clustering algorithm to extract system components is used, so the code can be easily removed to build distributed systems. At the same time, this paper also gives some module connection rules and module-deployment strategies suitable for J2EE partition. And a re-engineering process of enterprise’s legacy system to distributional system based on J2EE partition using this technology has been successfully realized, thus confirms this frame strong, practice and common.
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Computer Engineering. 2009, 35(14): 81-83. https://doi.org/10.3969/j.issn.1000-3428.2009.14.028In order to manage and store Point of Interest(POI) data of navigation E-map effectively in embedded navigation terminal with limited resources, based on Berkeley DB, this paper presents a block-oriented compression method for efficiently storing massive Point of Interest records on the embedded navigation terminal with limited resources. Considering the characteristics of POI, this method clusters, sorts and word-segments the data records, and stores these records based on compressed data block. It implements fast retrieval of POI records by building inverted index. Experimental results demonstrate that the method can provide high compressibility and retrieval performance.
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Computer Engineering. 2009, 35(14): 84-86. https://doi.org/10.3969/j.issn.1000-3428.2009.14.029Directed Acyclic Graph(DAG) is a kind of important network. A high-efficient algorithm to seek the shortest path arborescence and all shortest paths between any two vertices in DAG is presented. Arranging the vertices over again and using breadth first search for reference, this algorithm checks all out-arcs of each vertex starting with the source, and transforms the length values of the shortest paths at the head of each arc,and then it can get the shortest path arborescence and all shortest paths between any two vertices respectively in time O(m)and O(m(n-m1/2)). Correlative analysis and instances indicate that this algorithm is superior to other current algorithms in respect of computing complexity and operation.
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Computer Engineering. 2009, 35(14): 87-89. https://doi.org/10.3969/j.issn.1000-3428.2009.14.030The integration of heterogeneous data sources, which can effectively make use of the information sources and realize data sharing better, is a hotspot within the field of current data processing research. This paper describes an architecture of heterogeneous data integration system based on a Mediator-Wrapper middleware, and makes a deep research on the XQuery query processing, especially the key issues, such as query decomposition and optimization technology. This paper illustrates the realization of query decomposition and optimization with examples.
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Computer Engineering. 2009, 35(14): 90-92. https://doi.org/10.3969/j.issn.1000-3428.2009.14.031Reusing software resources at early stages of software development is insufficient. Reflection mechanism is successfully applied in the reuse of code component, but scarcely applied in the reuse of architecture and its constituents. This paper proposes a reflection mechanism supporting the reuse of architectural level designs, which generally describes the approach of software architecture reusing based on reflection mechanism. It illustrates the design and implementation process of supporting tool ArchBean Studio of software architecture reusing based on reflection mechanism. According to the approach, architects can accomplish the task of software design efficiently by reusing software architecture and its constituents.
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Computer Engineering. 2009, 35(14): 93-95. https://doi.org/10.3969/j.issn.1000-3428.2009.14.032This paper designs architecture of software asset management system based on the content of Reuse Asset Specification(RAS) and the ontology modeling theory. It presents an ontology-based semantic retrieval algorithm and gives an implementation in software asset management system. Compared with the traditional ways of information retrieval using complete match of keywords, the experiment is given to certify the improvement of the recall rate and precision rate of asset retrieval, which provides a feasible solution for enterprise asset management.
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Computer Engineering. 2009, 35(14): 96-97. https://doi.org/10.3969/j.issn.1000-3428.2009.14.033In order to develop spatial information service engine, which can try its best to meet the Quality-of-Service(QoS) of service requirements, a new Spatial Information Service Engine(SISE) framework is designed. In SISE, service requirements contexts are identified and different policies are used in management of service requirement queues and in the service requirements distribution. In order to meet the requirements of higher priority service, the higher QoS service requirement must be served at first.
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Computer Engineering. 2009, 35(14): 98-100. https://doi.org/10.3969/j.issn.1000-3428.2009.14.034Traditional congestion control algorithm is inapplicable for small buffer high speed networks. Aiming at this problem, this paper proposes a congestion control algorithm combining the end-to-end and middle-node together. This algorithm adjusts the window size self- adaptively by changing the values of adjustment factor a and protection factor c. Experimental results show that in small buffer high speed networks, this algorithm can realize high bandwidth utilization, high convergence speed and fairness of different RTT flow.
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Computer Engineering. 2009, 35(14): 101-103. https://doi.org/10.3969/j.issn.1000-3428.2009.14.035The node mobility models have an important influence on the topology of Mobile Ad hoc Networks(MANET), thus only the studies that under reasonable node mobility model are trusty. This paper generates the entity model, group model and area restricted model through expanding the NS2 and analyzes them in physical aspect and routing aspect. It shows that different mobility models have obvious different affection on the routing protocol. It is very useful in evaluating and studying routing protocol in MANET.
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Computer Engineering. 2009, 35(14): 104-107. https://doi.org/10.3969/j.issn.1000-3428.2009.14.036Factors influencing performance of P2P network structured by DHT mainly include inquiry efficiency of key words and cost of maintaining the steady of network. This paper starts with analyzing the relation of inquire efficiency and nodes scale, proposes the Application-oriented Lookup Service(AOLS). The logic relation among nodes adopts binary tree. It provides the algorithm of the logic relation organization in network and messages routing algorithm between nodes. Experiment indicates ALOS’s inquiry efficiency and cost of maintaining network’s stability have better performance.
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Computer Engineering. 2009, 35(14): 108-110. https://doi.org/10.3969/j.issn.1000-3428.2009.14.037It is a hot research field to interconnect Wireless Sensor Network(WSN) with the next generational network(IPv6). This paper starts the research from agent-access mode and direct access mode, discusses the all-IP access mode, which belongs to direct access mode, and analyzes the all-IP access mode in the application of single-soldier system. A conclusion is drawn from the analysis. It is believed that all-IP access mode is an important viewpoint to interconnect WSN with IPv6 network, and there is some important military significance in the future info-war, so it is worth carrying out some further work.
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Computer Engineering. 2009, 35(14): 111-113. https://doi.org/10.3969/j.issn.1000-3428.2009.14.038Aiming at the problem that data packet is easily lost in wired/wireless network, a Probe Packet-based Transmission Control(PPTC) strategy is presented. The sender periodically injects probe packets and the receiver estimates the network conditions. The inferences from the observations are utilized to regulate some information such as the transmission rate at the sender, the desirable properties of congestion control and loss packet discrimination. Simulation experimental results show this strategy is effective.
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Computer Engineering. 2009, 35(14): 114-116. https://doi.org/10.3969/j.issn.1000-3428.2009.14.039In order to avoid the demerits of large fluctuation of the sending rate for TCP-Friendly Rate Control(TFRC) strategy, a novel improved strategy called delay prewarning algorithm is presented. The prewarning signal is set up at sender to adjust the sending rate adaptively, which makes the sending rate of TFRC flows more smooth when competing with TCP stream. Simulation experimental results show this algorithm can improve the performance of TFRC effectively, and has performance of TCP-friendly and rate smoothly.
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Computer Engineering. 2009, 35(14): 117-119. https://doi.org/10.3969/j.issn.1000-3428.2009.14.040It is difficult for IntServ/RSVP model to realize QoS guarantee in Mobile IPv6(MIPv6) environment. Aiming at this problem, this paper proposes a new resource reservation scheme, which is based on the Hierarchical Mobile IPv6(HMIPv6). The resource reservation mechanism of mobile node intra-region is introduced. Comparison results with MRSVP and HMRSVP show that this scheme has high performance.
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Computer Engineering. 2009, 35(14): 120-121. https://doi.org/10.3969/j.issn.1000-3428.2009.14.041A network topology algorithm based on Address Forwarding Table(AFT) is presented, which gets the AFT information from the bridge MIB by Simple Network Management Protocol(SNMP), and deduces the indirect connective relationship. Compared with current algorithms, it does not require the completeness of the AFT information and a mass of compare. Simulation experimental results show this algorithm can calculate topology graph of 2 layer accurately.
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Computer Engineering. 2009, 35(14): 122-124. https://doi.org/10.3969/j.issn.1000-3428.2009.14.042Aiming at the problem that most of the previous approaches infer traffic matrix from either SNMP link loads or sampled NetFlow records. This paper designs a novel inference techniques that, by statistically correlating SNMP link loads and sampled NetFlow records. And it designs techniques that, by comparing notes between the above two information sources, identify and remove dirty data, and therefore allow for accurate estimation of the traffic matrices with the cleaned data. Experimental results prove that the algorithm has a higher accuracy.
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Computer Engineering. 2009, 35(14): 125-126. https://doi.org/10.3969/j.issn.1000-3428.2009.14.043This paper researches the problem of minimization of delay variation under the multicast end-to-end delay bounded and presents an efficient multicast routing algorithm. By altering the paths from the source node to the destinations, the nodes whose delay are smaller than the average achieves a new delay as big as possible and the nodes whose delay are above the average achieves a new delay as small as possible. Simulation results show that this algorithm can achieve a smaller delay variation.
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Computer Engineering. 2009, 35(14): 127-129. https://doi.org/10.3969/j.issn.1000-3428.2009.14.044Energy efficiency is a pivotal problem of Wireless Sensor Network(WSN). WSN can efficient prolong the lifetime of WSN via mobile sinks. Some fundamental design parameters in Mobile Wireless Sensor Network(MWSN) are investigated in this paper, such as cluster size, mobile sink velocity, mobile sink number, packet lifecycle and the impact of them on energy efficient. It proposes the optimization cluster hops scheme through careful analysis single hop scheme and multi hops scheme, and the extensive simulations is designed to evaluate the performance of mobile sinks WSN in terms of energy consumption.
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Computer Engineering. 2009, 35(14): 130-131. https://doi.org/10.3969/j.issn.1000-3428.2009.14.045The P2P streaming media based on network coding is analyzed. A push strategy is usted to promote the performance of network coding. Though the simulation experiment, some facts are discovered that the strategy will lead to linearly dependent blocks which are impossible to be used to recover original blocks and consume large numbers of bandwidth. The relation between topology and this problem is researched, and the topology construction rule that can effectively avoid this problem is presented.
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Computer Engineering. 2009, 35(14): 132-134. https://doi.org/10.3969/j.issn.1000-3428.2009.14.046To reduce the estimation’s complexity, an algorithm which estimates traffic matrix based on Gauss Mixed Model(GMM) is proposed. It decreases the times of clustering computing by fully utilizing the physical meaning of GMM and estimates the model parameter by Expectation- Maximization(EM) algorithm to improve the algorithm stability. Experimental results prove this algorithm is effective.
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Computer Engineering. 2009, 35(14): 135-137. https://doi.org/10.3969/j.issn.1000-3428.2009.14.047The latency and jittering produced by handoff between Access Points(APs) has a serious and negative impact on the quality of the real-time service. Through analysis of the process of handoff and existing improvement program, this paper proposes a scanning trigger mechanism based on dynamic domain values, which effectively avoids cache updates when STA is stable and the associated AP’s signal is good. This mechanism and a slice cache update algorithm are realized on the STA, which ensure timely update the cache and reduce the cost of each cache update and the handoff delay.
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Computer Engineering. 2009, 35(14): 138-141. https://doi.org/10.3969/j.issn.1000-3428.2009.14.048Stream-media and real-time application standing for new network application mode presents challenges to network performance and accurate measurement, which requires ISP provide efficient monitoring means meeting service level agreement. This paper proposes a network performance measurement system named NPMFO(Network Performance Measure Frame) based on One-Way Active Measurement Protocol(OWAMP)), which is an advice of IPPM working group. It discusses the effect of packet distribution and packet size to measurement result. Simulation results validate the methodology selected in the system.
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Computer Engineering. 2009, 35(14): 142-144. https://doi.org/10.3969/j.issn.1000-3428.2009.14.049Aiming at the problem of low service quality in Wireless Sensor Networks(WSNs), a Distributed Gap Fault-tolerant Scheme(DGFS) algorithm is presented. A set of energy-efficient event region detection fault-tolerant mechanism is built up. This algorithm exploits the spatial correlations among sensor nodes, syncretizes the median information, and judges the final state of the central node. Simulation experimental results demonstrate that when the faulty nodes ratio reaches 15%, this algorithm is still able to detect 86% of the faulty sensor nodes, and is characteristic of superior performance.
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Computer Engineering. 2009, 35(14): 145-147. https://doi.org/10.3969/j.issn.1000-3428.2009.14.050Extensible information system can use the domain project demand analysis method to separate the domain object from the system to produce the domain object guide. System manager can establish the domain object according to this guide to implement the system’s dynamic expansion, and the expansion system can implement the security access control. Through analyzing the Role-Based Access Control(RBAC) model, based on the integration framework of Struts, Spring and Hibernate, this paper proposes an access control scheme based on RBAC model, suitable for those dynamic information system, which can be Omni-directional expansion. And some relative key technologies for database design and module implementation are presented.
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Computer Engineering. 2009, 35(14): 148-150. https://doi.org/10.3969/j.issn.1000-3428.2009.14.051Aiming at problems in practical application of single biometric identity-based signature scheme, a novel multi-biometric identity-based signature scheme is proposed. The elliptic curve-based n-torsion groups are researched. Different biometric characteristics are syncretized. The biometric identity-based public key cryptosystem is introduced. Simulation experimental results show this scheme has better performances in security, stability and reliability, and is effective and feasible.
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Computer Engineering. 2009, 35(14): 151-153. https://doi.org/10.3969/j.issn.1000-3428.2009.14.052According to the network indicators’ effect, this paper proposes an algorithm integrated with grey correlation degree in grey theory and traditional analytic hierarchy process method to determine the indicators. It considers both objective and subjective factors. Experiments show that this method has a strict mathematical theory basis and a good practical utility. It can improve the evaluation methods’ credibility of network threat assessment.
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Computer Engineering. 2009, 35(14): 154-157. https://doi.org/10.3969/j.issn.1000-3428.2009.14.053Aiming at the defects of design theory of a kind of gray-scale watermarking system, this paper gives a series of theory results to guide this kind of gray-scale watermarking algorithms, including quantitative descriptions among the embedding strength, the robustness and the invisibility. The compromise between invisibility and the robustness is presented. The results are verified by the existing algorithms. Experimental results show that these results are of great guiding significance to gray-scale watermark algorithms design.
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Computer Engineering. 2009, 35(14): 158-159. https://doi.org/10.3969/j.issn.1000-3428.2009.14.054An approach of utilizing the chaos to Audio Video coding Standard(AVS) encoded frame is proposed, and it is integrated into the AVS CODEC. This algorithm encrypts DCT nonzero coefficients by using real-value chaotic sequence and then confuses DCT nonzero coefficients. Conducts simulate on three standard video sequence. Simulation results are tested on rm52j software platform, which indicates this algorithm is fast at encrypting data, good at security and affects little to compression.
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Computer Engineering. 2009, 35(14): 160-162. https://doi.org/10.3969/j.issn.1000-3428.2009.14.055This paper researches IPv6 basic header, and from the angle of network security, analyzes and discusses the fields which can be used to explore covert channel, presents two kinds covert channel creating methods. It focuses on the Bit-Convert methods based on Hop-Limit and separately gives out the key performance indictors such as communication capacity to each method. The preserving measures of covert channel based on IPv6 header are discussed.
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Computer Engineering. 2009, 35(14): 163-165. https://doi.org/10.3969/j.issn.1000-3428.2009.14.056In order to hold secure electronic conference in communication networks via insecure channels, a conference key distribution system should be constructed. The conference key distribution system is used for distributing a conference key shared among the participants of the conference and hence secure communications are achieved. By using the sealed lock, this paper proposes an identity-based conference key distribution scheme with user anonymity. It shows that, the scheme withstands passive attack, impersonation attack, and conspiracy attack, and provides forward security of the chairman. These properties make it quite effective and practical.
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Computer Engineering. 2009, 35(14): 166-167. https://doi.org/10.3969/j.issn.1000-3428.2009.14.057Aiming at the deficiency of traditional eXtensible Access Control Markup Language(XACML), this paper proposes the structure of Web services oriented interactive access control protocol and its implementation, in order to ensure the security of information transmission, this paper presents a framework of SAML based certification authority to design the matching mechanism. It takes the process of authorization for Web services access as an example, analyzing the process of interactive Web service access control protocol, and proves result that it can provide better support to the safety of access control for collaborative applications such as collaborative business environment and mobile business environment platform.
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Computer Engineering. 2009, 35(14): 168-170. https://doi.org/10.3969/j.issn.1000-3428.2009.14.058This paper presents an information hiding algorithm in Discrete Cosine Transform(DCT) domain. In order to improve the embedding capacity of a cover-image while maintaining the stego-image quality acceptable, it uses the random sequence to carry out distance control, selects the bit in which the secret information is embedded, regards seed of the random sequence as key, and completes information hiding by comparing the two DCT coefficients changed. Experimental results show that the method can take into account invisibility and robusticity. It can provide larger key space, achieves the adaptive hiding of the information, and extracts the embedding data from the stego-image without referencing to the original cover-image.
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Computer Engineering. 2009, 35(14): 171-172. https://doi.org/10.3969/j.issn.1000-3428.2009.14.059Based on ECC, by analyzing the engineering environment in WLAN and choosing appropriate ECC parameters, this paper describes a dual-signature scheme with tri-element authentication method. The scheme strengthens authentication for all the entities in WLAN. Any party’s identity should be checked by others when associating, so that it can enhance the security of access control in wireless network, restrict man-in-the-middle attack, and support the bandwidth transport in wireless network.
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Computer Engineering. 2009, 35(14): 173-174. https://doi.org/10.3969/j.issn.1000-3428.2009.14.060An algorithm for Region Of Interest(ROI) coding in JPEG2000, which can achieve the accurate bitrate control in each layer, is proposed in this paper. It codes the image without concerning the ROI. Then it counts out the bits allocated for the background and the ROI respectively. Under the constraints of the total bitrate, the proposal method reallocates the bits for both regions above. By this way, the ROI can achieve higher performance than the background due to the convex characteristic of rate-distortion function. Both the ROI and its priority can be modified in the algorithm, and the algorithm produces a fully compliant JPEG2000 code stream.
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Computer Engineering. 2009, 35(14): 175-177. https://doi.org/10.3969/j.issn.1000-3428.2009.14.061Aiming at the problem that the traditional median filtering arithmetic blurs the image, this paper introduces an improved algorithm by adding threshold comparison to the traditional median filtering algorithm, which can make the image maintain much more details after processed. As the traditional methods need too many clock periods to implement the median filtering in Field Programmable Gate Array(FPGA), a new circuit is designed, which can quickly get median value of some numbers in three clock periods. The simulation result shows that the algorithm not only can filter the noise better, but also can make the image much clearer, and the designed circuit can implement the arithmetic quickly and efficiently.
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Computer Engineering. 2009, 35(14): 178-180. https://doi.org/10.3969/j.issn.1000-3428.2009.14.062A novel method of image filtering is proposed using the independent component analysis of the characteristics. The original image and the overall translation with a row to the right of the image are regarded as an Independent Component Analysis(ICA) observation signal. Strong correlation between these two images of the matrix of information for analysis can be sharpening images. ICA shows that it has a high pass filtering performance. Computer simulation experimental results show that this method to extract sharpening image with strong lays of graphics and high location accuracy is an effective filtering method.
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Computer Engineering. 2009, 35(14): 181-183. https://doi.org/10.3969/j.issn.1000-3428.2009.14.063Multiphase level set method of Chan-Vese(CV) model is not suitable for real-time application for having numerical stability constraints and its low efficiency. Aiming at this disability and based on the specialty of human brain, a fast method to solve is developed. This approach computes the histograms of four areas which can be used to distinguish the area cut by two curves, and constructs signed tables. The points of the histogram are changed to other clusters and the sign of the points are checked according to the change of the energy. And the improved mean of small neighborhood method is used to optimize the results and get the final edges. Experimental results show that the new model can get the better results in an efficient way.
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Computer Engineering. 2009, 35(14): 184-186. https://doi.org/10.3969/j.issn.1000-3428.2009.14.064Aiming at efficient recognition of large-scale closed space graph, an overall scheme of recognition based on turning is given, considering the various stages related to recognition. Centering on the uniqueness and determinacy of single closed graph, a counter-clockwise or clockwise recognition method for single closed graph based on beamed-close of turning is put forward. With the region division rules, dynamic optimization rules and priority setting rules, the efficient recognition of large-scale closed space graph is achieved. The effectiveness of the method is proved by the practical application.
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Computer Engineering. 2009, 35(14): 187-189. https://doi.org/10.3969/j.issn.1000-3428.2009.14.065By analyzing image data’s demands for semantic information, a structural method is adopted to express information in images, and a similarity algorithm which contains semantic information to help retrieve images is defined. To a certain extent, this method overcomes limitations of two common image retrieval methods, i.e., content based image retrieval, and text based metadata image retrieval, both of which lack semantic information for match. The prototype system proves its effectiveness through fruitful semantic information of collaborative annotation and accuracy of image retrieval.
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Computer Engineering. 2009, 35(14): 190-191. https://doi.org/10.3969/j.issn.1000-3428.2009.14.066Aiming at the characteristic of the lighting energy equipment, this paper puts forward a kind of energy-conserving method to combine Wireless Communication Network(WCN) with control of the street light. It makes use of wireless way to transmit to send and accept the information of controlling, adopts variable reactor energy-conservation to control technical design and develop street light energy-conservation to fit, probes into and uses controlling algorithms fuzzily, optimizes the energy-conserving question that the street light operates with the electricity, and sets up corresponding fuzzy control system. Result proves the system is systematic and very effective in energy consumption for saving the street light illumination .
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Computer Engineering. 2009, 35(14): 192-194. https://doi.org/10.3969/j.issn.1000-3428.2009.14.067There is a great potential danger in the transportation of hazardous goods. In order to obtain and display the real-time state and logistics information of the hazardous goods, the platform combines GIS/GPRS technologies. TCP protocol is chosen as the protocol of the GPRS network to ensure the bidirectional communications according to the characteristic of the GPRS network. A remote monitoring platform for hazardous goods in container, based on ASP.net and SQL, is designed to ensure transportation safety. The design and application of platform intensively strengthens the safety of hazardous good transportation and reduces property losses.
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Computer Engineering. 2009, 35(14): 195-196. https://doi.org/10.3969/j.issn.1000-3428.2009.14.068This paper presents an algorithm that cuts the sheet into three sub sheets by two dividing lines which are perpendicular to each other. Every sub sheet contains a group of strips which have the same orientation and length. Use dynamic programming algorithm to determine the optimal layout of the strips in the sub sheets, and use enumeration method to determine the position of two dividing lines so as to maximize the value of the whole sheet. The computational results indicate that the algorithm can improve the material usage of the patterns, and the computation time of the algorithm is reasonable for practical use.
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Computer Engineering. 2009, 35(14): 197-199. https://doi.org/10.3969/j.issn.1000-3428.2009.14.069This paper presents a design method of multi-view processor. The system includes video input module, video matrix module, A/D transform module, video signal processing module, video output module and control module. Aiming at the characteristics of multi-view processing, it gives the implementation of key technologies such as signal conditioning, image scaling and image segmentation. Practical application shows that the effect of the system is good.
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Computer Engineering. 2009, 35(14): 200-202. https://doi.org/10.3969/j.issn.1000-3428.2009.14.070Aiming at the question that the traditional method for discerning risk can not come true the real-time recognition of risk statue in the shield tunneling constructing process, this paper proposes a feature selection method which combines Adaptive Genetic Algorithm with Support Vector Machine(AGASVM). It is used to filter a pivotal feature subset which is super correlative with risk of constructing quality. Experimental result shows that the pivotal feature subset selected by AGASVM can make the classification accuracy higher when it is used in the real-time recognition of risk statue. The dimension of pivotal feature subset is obviously smaller than the one of original factors set, and the most of pivotal features are the same as the ideas of domain experts.
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Computer Engineering. 2009, 35(14): 203-205. https://doi.org/10.3969/j.issn.1000-3428.2009.14.071For the need of Charge Coupled Device(CCD) signal acquisition of some payload in spaceflight, a CCD signal acquisition scheme based on USB 2.0 is presented, including the hardware interface design and software design. The hardware architecture is implemented with FPGA and EZ-USB, the USB interface IC is in slave mode and the signal transmission mode is batch transmission. The signal acquisition application is designed on the platform of VC++6.0. The system realizes CCD signal acquisition and runs steady, which is proved with the emulator ISE and Modelsim, and the hardware platform based on EZ-USB
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Computer Engineering. 2009, 35(14): 206-208. https://doi.org/10.3969/j.issn.1000-3428.2009.14.072The multi-class object recognition method usually suffers from the problem of curse dimensionality after extracting feature. This paper proposes a new approach for learning a discriminative model of object classes combined affinity propagation clustering. By using Affinity Propagation(AP) , a representative visual vocabulary can be obtained. Experiment in Sowerby databases shows that it is superior to the recognition rate of k-means algorithms .
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Computer Engineering. 2009, 35(14): 209-211. https://doi.org/10.3969/j.issn.1000-3428.2009.14.073The purpose of the Maximum Margin Criterion(MMC) is to maximize the inter-class scatter while simultaneously minimizing the intra-class scatter after the projection, and does not suffer from the small sample size problem. Compared with original MMC method, by multiplying the defined weights and regulating the parameter, the new method can still better manifold local structure information. Experimental results on Olivetti Research Laboratory(ORL) face database show that the method can recognize the face images efficiently and enhance the recognition rate.
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Computer Engineering. 2009, 35(14): 212-214. https://doi.org/10.3969/j.issn.1000-3428.2009.14.074Aiming at the problem which is appeared in Knockout algorithm that the color estimate model is only applied to smooth image, a new color estimate model is proposed. The unknown region is divided into many subregions by region growth algorithm, rectangular block is made out based on the point which is nearest to the subregion in the foreground and background contour line. The weighted average values of foreground and background pixels color in rectangular block are computed respectively. The values are taken as the foreground and background color components. The improved color estimate model has better behavior in the natural image matting for the image which the edge color is very different.
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Computer Engineering. 2009, 35(14): 215-217. https://doi.org/10.3969/j.issn.1000-3428.2009.14.075This paper proposes a novel face alignment algorithm: improved Bayesian Tangent Shape Model(BTSM). It isolates gesture parameters and shape parameters, deals with these two parameters respectively and uses radius of curvature as the number of dynamic search of this landmark. Experiments show that the algorithm can make up for the defects that BTSM can not well handle the alignment of multi-gesture face images and the approach can improve the effectiveness in both speed and accuracy.
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Computer Engineering. 2009, 35(14): 218-220. https://doi.org/10.3969/j.issn.1000-3428.2009.14.076By combining several parameters selection approaches of Support Vector Machine(SVM), this paper proposes a method that defines parameters directly by analyzing training samples. Experimental results based on several standard test data sets show that the method achieves better prediction accuracy and consumes less time compared to traditional grid search methods. It provides one way to deal with the problem of selecting parameters and time consuming in application of SVM.
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Computer Engineering. 2009, 35(14): 221-223. https://doi.org/10.3969/j.issn.1000-3428.2009.14.077Aiming at the limitation of generalization ability when the speaker identification system falls short of training data, this paper proposes a new method of complex Gaussian Mixture Model(GMM) based on Semi-Supervised Learning(SSL). It uses complex GMM to model the feature distribution of all speakers and the training period adopted SSL based on iterative algorithm. Experimental shows that this new method can take full advantage of unlabeled data on the self-adaptive updating, improve the performance, get higher recognition rate compared with traditional GMM, and effectively enhance the generalization ability of system.
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Computer Engineering. 2009, 35(14): 224-226. https://doi.org/10.3969/j.issn.1000-3428.2009.14.078A new method based on two-dimensional FDA by combining with weighted-symmetry face is proposed for face recognition. This new algorithm introduces the even symmetry samples and the odd symmetry samples of face images. The even symmetry samples and the odd symmetry samples are used to form new face samples by a weighted actor. The optimal feature projection space of the new face samples is calculated through two-dimensional FDA, algorithm to classify the extracted features. This new method uses effectively not only the advantages of two-dimensional FDA but also the symmetrical properties of facial images to achieve better recognition rate. The influence of different weighted factor make is analyzed in this paper. Choosing the optimal weighted factor achieves the best performance. Experimental results on ORL database show the efficiency of the new method.
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Computer Engineering. 2009, 35(14): 227-229. https://doi.org/10.3969/j.issn.1000-3428.2009.14.079In text classification area, Vector Space Model(VSM) is the most widely used model while it has two drawbacks: high dimensions and warped space. This paper presents a new model based on orthogonal decomposition. In this model, higher dimensional vectors of texts are mapped in a lower dimensional space which uses categories as its coordinate axes to solve these two drawbacks. Experiment shows that under the new model, the classification process is speeded up to a considerable degree and the precision is increased.
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Computer Engineering. 2009, 35(14): 230-232. https://doi.org/10.3969/j.issn.1000-3428.2009.14.080There are some problems when task allocation algoritm is dynamic and uncertainty environments. This paper describes the task allocation environment with Dynamic Fuzzy Set(DFS) and presents a dynamic task allocation method that is used to improve veracity and reduce the error. It is proved that this model can simulate the process of task allocation to get the optimal task allocation strategy. Example test results indicate the rationality and validity of the algorithm.
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Computer Engineering. 2009, 35(14): 233-235. https://doi.org/10.3969/j.issn.1000-3428.2009.14.081Aiming at the problem that Interactive Genetic Algorithm(IGA) lacks a way of measuring comment uncertainty, a method with grey for comment uncertainty of evolutionary individuals is proposed, which the individual fitness is an interval. Through analyzing these fitness grey levels, information reflecting the distribution of an evolutionary population is abstracted and the adaptive probabilities of crossover and mutation operation of an evolutionary individual are presented. The algorithm is applied to a fashion evolutionary design system, the simulation results indicate that the algorithm can effectively alleviate users fatigue and improve efficiency of optimization.
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Computer Engineering. 2009, 35(14): 236-237. https://doi.org/10.3969/j.issn.1000-3428.2009.14.082Aiming at the problem that the Least Squares Support Vector Machines(LSSVM) is sensitive to noises or outliers, a LSSVM model incorporating with a prior knowledge on data is proposed. Information of noise distribution for samples is introduced in the training process. A strategy based on the sample affinity is presented to discriminate data with noises. A fuzzy membership is automatically generated and assigned to each corresponding data point in the sample set by using the strategy and the noise model. Experimental result shows that the proposed model has better classification accuracy with noise data.
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Computer Engineering. 2009, 35(14): 238-240. https://doi.org/10.3969/j.issn.1000-3428.2009.14.083In order to test and evaluate the performance of Multi-Objective Evolutionary Algorithm(MOEA), multi-objective optimization test problems are suggested in this paper on the following perspectives: constrained condition, uniform representation of Pareto-optimal solutions and hindrance to reach the global Pareto-optimal front. NSGA-Ⅱ is used to make experiments on these test problems and the non-dominated fronts are visualized. Test results show that these problems can test the algorithm’s performance effectively in above three aspects.
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Computer Engineering. 2009, 35(14): 241-242. https://doi.org/10.3969/j.issn.1000-3428.2009.14.084A novel Boosting-based Binary Tree-SVM(BBT-SVM) is presented. Based on the distributing probability and pattern diversity of each obstacle in urban traffic scenes, a compatible tree structure of SVM is designed. A Boosting-based ensemble learning approach is applied to reduce the transfer error and it improves the generalization performance of per-node classifier. The improved BBT-SVM can correctly recognize six kinds of normal obstacle patterns in urban traffic scenes. Experimental results show the improved BBT-SVM can efficiently recognize six kinds of normal obstacle patterns in urban traffic scenes.
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Computer Engineering. 2009, 35(14): 243-246. https://doi.org/10.3969/j.issn.1000-3428.2009.14.085Traffic light with countdown timer is widely used today, this paper introduces an efficient but simple control algorithm. This algorithm analyzes the statistics of vehicle passing rates of each lane near traffic lights and classifies them by online clustering, and evaluates optimal solutions of each category by genetic algorithm. It aims at sufficient category refinement and solution optimization. Theoretically, it can allot green light time for each lane proportional to their vehicle densities. Simulation verifies its effectiveness in reducing average waiting time of vehicles, compared with other algorithms supporting counting-down timers.
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Computer Engineering. 2009, 35(14): 247-248. https://doi.org/10.3969/j.issn.1000-3428.2009.14.086This paper designs a new brush rendering method, through adopting a Gaussian image pyramid to generate a series of reference images, using different brushes to paint layer by layer in order to simulate the rendering stages from coarser to finer. This method uses statistics method to determine the brush’s color and pixels’ eight-neighbor concept to control the direction of brush strokes. Experimental result shows that a photo can be transformed to aesthetic images by setting up different parameters.
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Computer Engineering. 2009, 35(14): 249-251. https://doi.org/10.3969/j.issn.1000-3428.2009.14.087Aiming at the problems in influence evaluation of beyond visual range air combat models, the process of it supported by datalink is analyzed. The influence of datalink on beyond visual range air combat is researched. On basis of this, the first shot exponential model and probability model are modified. The influences of time delay on first shot probability and kill rate in beyond visual range air combat are also studied. Experimental results show that because of the larger influence of time delay, it should be processed during the combat period.
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Computer Engineering. 2009, 35(14): 252-254. https://doi.org/10.3969/j.issn.1000-3428.2009.14.088The position and attitude of unmanned helicopter is the basis of autonomous flight control of helicopter. This paper calculates the three-dimension coordinates and attitude of the unmanned helicopter’s marking-points based on the principle of binocular vision, by detecting and tracking marking-points, and matching the marking-points using an algorithm called constraint of epipolar based on order of consistency. A platform based on binocular vision for taking experiment of controlling small unmanned autonomous helicopter is designed, which can be used to verify flight control model and algorithms.
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Computer Engineering. 2009, 35(14): 255-257. https://doi.org/10.3969/j.issn.1000-3428.2009.14.089Aiming at existing problems of the delay of scheduling task, policy of administering buffer and algorithm of 2-D DCT, this paper proposes an optimized method for designing embedded system co-operating of hardware and software based on IPv6 network video application. It implements the circuit, operating system and network protocol stack of the embedded system. It transmits, decodes and plays the video streaming in IPv6 network for test. The result indicates when the space resolution is 320×240 and the time resolution is 25 frame/s, the playing menu is fluency and has not waiting delay.
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Computer Engineering. 2009, 35(14): 258-260. https://doi.org/10.3969/j.issn.1000-3428.2009.14.090The interconnect resource for Field Programmable Gate Array(FPGA) based on Static Random Access Memory(SRAM) is analyzed. A test matched sets algorithm with automatic generation is presented, which has no relation to application. By constructing the routing resource graph, this algorithm assigns a dynamic weight of each edge by the direction of nets and runs the modified Kruskal algorithm to obtain the minimum numbers of test configurations. For different FPGA routing architectures, the cover rate to faults of stuck-open and stuck-closed reaches 100%, and has some characteristics such as few number of testing configurations, high operating speed and has no relation to hardware structure.
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Computer Engineering. 2009, 35(14): 261-263. https://doi.org/10.3969/j.issn.1000-3428.2009.14.091Aiming at the problem of low efficiency in military operation simulation system development, a rapid construction method of military operating simulation system based on C/S mode is presented. The whole structures of system are introduced. Through three level designs of simulation supported level, rapid construction level and application level, the construction of the whole system is made as the simulation process with characters of both connective and independent one. Some software techniques are used to implement this system. Experimental results show this method can promote the efficiency of development effectively.
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Computer Engineering. 2009, 35(14): 267-269. https://doi.org/10.3969/j.issn.1000-3428.2009.14.093Aiming at bilingual corpora is critical resources for developing statistical machine translation system, this paper presents a method which automatically mines bilingual parallel Web page form Web. Different from mining data from pre-specified Web sites, the system is developed to mine parallel Web page from the entire Web, it is greatly suitable for new content domains and language pairs. It implements a parallel Web page mining system. Experimental results show that the system can provide large scale and high quality parallel Web page for statistical machine translation.
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Computer Engineering. 2009, 35(14): 270-272. https://doi.org/10.3969/j.issn.1000-3428.2009.14.094Aiming at the problem of node leak for mobile object monitoring. This paper proposes a node control strategy for mobile object monitoring in Wireless Sensor Networks. In the strategy, monitoring node imposes the position messages of the neighbor hop node to calculate the velocity-estimated function and orientation-estimated function. The nodes within scope of the orientation-estimated function to calculate the arrival estimated time of the mobile objects by the velocity-estimated function, and increase the duty cycle after this time for a period to improve the probability of sensing. The simulation results show that this strategy improves the probability of sensing of nodes, decreases the monitoring distortion degree of Wireless Sensor Networks.
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Computer Engineering. 2009, 35(14): 273-276. https://doi.org/10.3969/j.issn.1000-3428.2009.14.095A hierarchical multimodal integration method based on Interaction Semantics(IS) is presented, which contains probability and time-constrain technology. The interaction intentions are distilled from multimodal inputs and a task is confirmed. The method is applied in virtual environment, and according to practical requirements, several kinds of multimodal interact technologies are designed and implemented. The integration process is tested by some cases. Simulation experimental results show this method is effective and feasible.
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Computer Engineering. 2009, 35(14): 277-279. https://doi.org/10.3969/j.issn.1000-3428.2009.14.096Aiming at the existing problems of conventional medical monitor, this paper proposes a solving scheme of novel medical monitor based on the full network condition which has the stronger ability of information processing, as well as maintainable. In particularly, it adopts the service-oriented method of system design, designs collaborative monitoring service platform. It is clinical trial in a hospital result proves, it can implement monitoring of ECG parameter,.
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Computer Engineering. 2009, 35(14): 280-282. https://doi.org/10.3969/j.issn.1000-3428.2009.14.097This paper introduces the industrial chain of high performance embedded processor used in distributed cluster computer and analyzes the technical feature of the each node in the chain, such as the vendor of CPU core, processor developer, the vendor of system software, the producer of embedded computer. It explores the development of high performance embedded processor and gains some experience. It suggests to cooperate with the vendor of system software and the producer of embedded computer and exerts the ability of software and hardware co-design to develop the high performance embedded processor. It predicts that the technique of multi-core and high speed bus circuit is the road to future.
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Computer Engineering. 2009, 35(14): 283-285. https://doi.org/10.3969/j.issn.1000-3428.2009.14.098Aiming at GPS software receiver, this paper proposes an implement algorithm for tracking part including code tracking and carrier tracking. The algorithm is simulated in Matlab based on simulation data and implemented in C based on real data in PC. The C program runs on GT3000A platform which integrates ARCA3 embedded microprocessor. Experiment proves that the algorithm carries out the tracking function of C/A code phase and carrier frequency, and decodes the navigation data.
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