05 July 2010, Volume 36 Issue 13
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Computer Engineering. 2010, 36(13): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2010.13.001In order to get rid of the limitation of D-S combination rule and improve rules, a new combination rule based on the weighting factor of conjunctive and complementary pooling and Pignistic probability transformation is introduced. Beginning with the theory of the conjunctive and complementary pooling, the new formula of basic probability assignment is inferred. The evidence combination rule is obtained through the quantification research on the weighting factor of conjunctive and complementary pooling. With the purpose of reducing the influence of combination sequence and providing a reliable decision-making, a Pignistic probability transformation is used to reassign the basic probability assignments of multi-element propositions to each element. Through analyzing the number examples, and compared with other improved methods, the results show this new solution can efficiently solve the conflicting evidence, the loss of majority opinion, the robustness of algorithm, the fairness of distribution and the efficiency of decision.
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Computer Engineering. 2010, 36(13): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2010.13.002Aiming at the incomplete information system with “ ”, based on analysis of some extended rough set models, this paper classifies attribute set. The proportions of each classification and contribution degree of attribute set are defined respectively. Indiscernibility relation based on attribute contribution degree is presented. Analysis on the example shows that the indiscernibility relation is more agile and reasonable, and the relation in special conditions equals another indiscernibility relation.
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Computer Engineering. 2010, 36(13): 7-8,12. https://doi.org/10.3969/j.issn.1000-3428.2010.13.003
Aiming at CT lung nodule detection, the false positive rate is a major disturb factor. This paper proposes a Radial Gradient Index(RGI)- based method. Based on RGI map of CT image, RGI filter is set to reduce false-positive nodules. Experimental results show this method can efficiently reduce the False Positive Rate(FPR) in automated lung nodule detection.
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Computer Engineering. 2010, 36(13): 9-12. https://doi.org/10.3969/j.issn.1000-3428.2010.13.004This paper proposes a multichannel speech enhancement system based on non-uniform filterbank which can animulate heuring perceptual model. To achieve the same frequency resolution, the system uses less channels than that based on uniform filterbank. Simulations show the system achieves better quality in terms of Itakura-Saito(IS) distance than uniform filterbank-based speech enhancement system.
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Computer Engineering. 2010, 36(13): 13-14,17. https://doi.org/10.3969/j.issn.1000-3428.2010.13.005The three-dimension geometry signal is usually nonlinear and non-stationary. According to this characteristic, a novel method based on Empirical Mode Decomposition(EMD) is presented to process the geometry signal. The main idea is to decompose the signal into some different detail components called Intrinsic Mode Function(IMF). The signal is parameterized as a spherical signal, transformed to the plane signal and sampled regularly. The translated signal can be processed as an image, using bid-empirical mode decomposition. After getting several image IMFs, these IMFs are inversely mapped to geometry signal and the geometry signal’s IMFs are got. The advanced power of the algorithm is proved by a number of experiments, including denoising and enhancement.
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Computer Engineering. 2010, 36(13): 15-17. https://doi.org/10.3969/j.issn.1000-3428.2010.13.006
Taking advantage of group theory Cayley graph, a P2P dynamic overlay network model CPN is built, and its DHT protocol is defined. CPN is consistent with the definition of small-world feature, which has high clustering coefficient, robustness and supports grouping features. Because it is symmetric overlay network, its routing algorithm, compared with the classic P2P overlay network, is easier to implement. Experimental results show that CPN has better performance than the common overlay network protocol does.
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Computer Engineering. 2010, 36(13): 18-20,23. https://doi.org/10.3969/j.issn.1000-3428.2010.13.007Aiming at the characteristics of two-hop OFDMA Relay network, classical packet schedule algorithms(RR, MaxC/I, PF) are extended to two-level schedule algorithms(E-RR, E-MaxSNR, E-PF). Simulation results indicate that the three new two-level schedule algorithms have good system performance compared with the former algorithms. E-RR obtains good performance on user fairness, E-MaxSNR has maximum system throughput and E-PF achieves tradeoff between system throughput and user fairness.
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Computer Engineering. 2010, 36(13): 21-23. https://doi.org/10.3969/j.issn.1000-3428.2010.13.008The recognition problem is converted into a sine wave testing procedure because the common signals modulated by different intrapulse modulation type reveal different sine generation properties by the different order moment in different time-varying delay and the conjugate of the order. Computer simulation results show that the proposed method is effective to recognize the common intrapulse modulation type signals at a lower signal-to-noise ratio and without any priori knowledge.
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Computer Engineering. 2010, 36(13): 24-26,29. https://doi.org/10.3969/j.issn.1000-3428.2010.13.009The implementation of the CPU-GPU hybrid DGEMM is carried out on the ATI platform to improve the computing performance by computing both on GPU and CPU. Experimental results show that when matrix size is large, its performance on AMD Phenom II X4 940 and ATI FireStream 9270 platform, compared with using GPU alone, can be improved 16% on average. The evaluation method is verified along with the discussion of the factors which impact the hybrid DGEMM performance.
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Computer Engineering. 2010, 36(13): 27-29. https://doi.org/10.3969/j.issn.1000-3428.2010.13.010This paper considers the features of clustering and classification synthetically. According to the clustering results, it constructs training sets by studying and utilizing structure information of initial clusters. The data sets are re-plotted according to iterative classification theory and an improved method based on iterative classification is proposed. Experimental results show that the method improves the accuracy of clustering results. It is a new way to obtain satisfactory clustering results.
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Computer Engineering. 2010, 36(13): 30-33. https://doi.org/10.3969/j.issn.1000-3428.2010.13.011Aiming at the problems of incomplete requirements description, ambiguity and inconsistency in traditional requirements analysis method of software developments, this paper proposes a formalization requirements analysis method. It introduces to get the software requirements specification according to the requirements of the user with formalization method, design the software Unified Modeling Language(UML) model and to describe the UML model with formalization method, do the requirements verification to the formalization UML model with the method of formalization verification, for make sure the correctness of the designed software UML model. Experimental results show that the formalization requirements analysis method can overcome the problems in traditional requirements analysis method.
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Computer Engineering. 2010, 36(13): 34-36,39. https://doi.org/10.3969/j.issn.1000-3428.2010.13.012Collaborative filtering has been applied in personalized recommendation system successfully, sparsity problem and scalability problem become two big problems which remain unresolved. To slove the problem of traditional method, this paper propose a decision-making method relying on the number of neighbors. The method compares the number of user’s neighbors and item’s neighbors in every unpredicted position, and chooses the bigger one to make predicting. In addition, a reasonable and effective measurement is put forward to judge predicting. Experimental result shows that the quality of recommendation is largely improved.
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Computer Engineering. 2010, 36(13): 37-39. https://doi.org/10.3969/j.issn.1000-3428.2010.13.013To improve the satisfaction degree of Web page ranking, this paper proposes a new algorithm based on the feature selection technology. This algorithm utilizes multiple feature selection to choose a subset of a paper’s feature set, and selects those features with largest total importance scores and smallest total similarity scores. Experimental results on the public dataset in the region of information retrieval show that this algorithm has higher performance than traditional ranking algorithms.
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Computer Engineering. 2010, 36(13): 40-44,41. https://doi.org/10.3969/j.issn.1000-3428.2010.13.014
In light of the heterogeneous of various database metadata as well as the field model to package metadata and the table structure to storage metadata require established by a mass of manual work, this paper puts forward database metadata processing based on Common Warehouse Metamodel(CWM) and Eclipse Modeling Framework(EMF), including getting, packaging, expansion, persistence and so on, as well as the realization of the field model and the generation of table structure. Results prove that database metadata processing based on CWM and EMF can solve the heterogeneous of database metadata and replace the manual work to build field model and table structure, and reduce the workload.
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Computer Engineering. 2010, 36(13): 42-44. https://doi.org/10.3969/j.issn.1000-3428.2010.13.015Nutch is an open source search engine based on Java. In view of Nutch disappointment which uses Chinese individual character segmentation and can not realize the PageRank computation, the MapReduce-based PageRank computation is designed and implemented in the foundation of improving the PageRank algorithm. JE Chinese word segmentation is added to improve Chinese segmentation on Nutch. Experimental results show that the improved Nutch raises the inquiry rate of accuracy and the ranking quality of Chinese Web.
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Computer Engineering. 2010, 36(13): 45-47. https://doi.org/10.3969/j.issn.1000-3428.2010.13.016In the ontology building process, the critical information of ontology is submerged in the redundancy of the concept and the relationship between the concepts with the concepts’ rising, if it is not optimized. This paper presents a dynamic optimization algorithm of ontology based on Formal Concept Analysis(FCA). With the knowledge of building ontology prototype based on FCA theory, through removing the redundant concepts and the relation of them, it achieves the purpose of optimization, so as to eliminate redundant in ontology, make the relationship between the concepts be more clearly, the critical information key content be more prominent.
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Computer Engineering. 2010, 36(13): 48-50,53. https://doi.org/10.3969/j.issn.1000-3428.2010.13.017Based on the Scalable Vector Graphics(SVG) spatial representation model and reasonable database structure, this paper presents an optimization selection strategy for spatial index algorithm. According to the design mode theory, it designs a spatial data index system with high cohesion and low coupling. The system provides the ability of creating spatial index in parallel, and can realize the capability of concurrently querying heterogeneous XML-enabled spatial database. Experimental results show that the system improves about 66 percents efficiency compared with SQL language.
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Computer Engineering. 2010, 36(13): 51-53. https://doi.org/10.3969/j.issn.1000-3428.2010.13.018Aiming at the problem of very strong subjectivity in the attribute weight determination of dataset in identifying approximately duplicate records based on the character string matching method, the paper puts forward a method based on fuzzy integrated estimation to get attribute weight. It estimates the components of all attribute’s importance by multi users, and gets the attribute’s weight through fuzzy mapping, based on which the approximately duplicate records are identified. It can be proved from theory and practice that the method can objectively get all attribute weight, thus it has a higher precision in identifying approximately duplicate records.
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Computer Engineering. 2010, 36(13): 54-56. https://doi.org/10.3969/j.issn.1000-3428.2010.13.019Aiming at some shortages like monotony of semantic description and lack of expansibility and adaptability, a semantic-component description model based on reflection is proposed. Based on the traditional component model, this model introduces ontology and reflection technology, makes the semantic description of component diverse and is able to dynamic update the component in accordance with system requirements and changed runtime environment. It supports automating combination and validation. It is used in mobile application, and the results show the improvement of self-adaptive for it.
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Computer Engineering. 2010, 36(13): 57-58,61. https://doi.org/10.3969/j.issn.1000-3428.2010.13.020This paper proposes ThreadXML programming model which is a rapid multithread programming model and can be embedded into most normal programming languages. ThreadXML is a sort of markup language which can enhance programming productivity and be easily designed by visual programming tool. A ThreadXML compiler and a ThreadXML related visual programming tool implementation method are presented. ThreadXML compiler is implemented by using object-oriented technology and code template technology, which is able to transform ThreadXML code into mostly common executable code. ThreadXML related visual programming tool is implemented by using graphic element and code template technology.
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Computer Engineering. 2010, 36(13): 59-61. https://doi.org/10.3969/j.issn.1000-3428.2010.13.021By introducing the concept of weighted support and minimum support expect, a new model of weighted association rule mining is presented in order to solve the problem that items have not the same importance in datasets. Based on the model, a new improved algorithm for mining weighted association rules based on association graph is proposed. The algorithm only scans the database once, stores the frequent 2 itemsets with association graph, and builds an effective pruning strategy to reduce the computation. It improves the efficiency of weighted frequent itemsets generation.
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Computer Engineering. 2010, 36(13): 62-64. https://doi.org/10.3969/j.issn.1000-3428.2010.13.022Architecture design decisions are implicitly embedded in final architecture artifacts in current design process, which leads to difficult communication among stakeholders, high cost of software evolution and hard to reuse architectural decisions. Aiming at the problems, this paper proposes a meta-model of architecture design decision by analyzing its attributes and decision-making process, and a management tool design is brought forward, which combines the codification and personalization strategies to achieve explicit documentation, management and reuse of architecture design decisions.
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Computer Engineering. 2010, 36(13): 65-67. https://doi.org/10.3969/j.issn.1000-3428.2010.13.023This paper proposes the basic concepts of single item schema, two item schema and three or more item schema, and presents the representation method of two item schema and three or more item schema, by which candidate sequences not exist in fact are not produced, so that the number of candidates is reduced and the speed of computing sequence schema is enhanced. Based on Apriori method and three schemas, by using irredundant produce schemas principle and three-level optimum method, a structural dynamic optimum method of sequential pattern discovery is proposed.
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Computer Engineering. 2010, 36(13): 68-69,72. https://doi.org/10.3969/j.issn.1000-3428.2010.13.024Computing system performance degradation is mainly due to the loss of system resources, in order to avoid the high cost due to software aging, it is needed to study the resources consumption rule in the process of aging. Through building simulation environment, the performance degradation process is simulated and the resources data of computing system are collected. The noise data are removed using wavelet technique, the linear regression model and state-space model are established to analyze the resources consumption rule. Experimental results show significant availability for detection of usage of system resources, which can estimate the performance of computing system and offer data support for establishing software rejuvenation policy.
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Computer Engineering. 2010, 36(13): 70-72. https://doi.org/10.3969/j.issn.1000-3428.2010.13.025A describing language, R2XL(Relational To XML Language), is presented to express mappings of distributed database data into XML that conforms to user’s need. On the basis of this analysis, a system of integrating distributed database is proposed based on XML to achieve transparent access and unified query. The key questions are researched which include query processing, splitting method of distributed database data and the corresponding method to integrate these data fragments etc.
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Computer Engineering. 2010, 36(13): 73-75. https://doi.org/10.3969/j.issn.1000-3428.2010.13.026This paper presents a self-adaptive evolution model——DESM, which is based on pervasive computing. It describes the structure and function through the internal definition of DESM, and uses graph for the causes of the ubiquitous environment and timing of evolution to model, so as to ensure the consistency of the system. It verifies the feasibility and the effectiveness of the model during an information management system, and describes its internal evolution with timing diagram.
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Computer Engineering. 2010, 36(13): 76-78. https://doi.org/10.3969/j.issn.1000-3428.2010.13.027Content information is the topic information of a Web page excluding links, navigations, advertisement and so on. This paper proposes and implements an information extraction algorithm including content Web page. By taking a top-down traversing of HTML tag tree of Web page and continuously analyzing the statistics within like text link rate and continuous text length, it can locate the best content information region and extract the text content. Experimental results show the high feasibility and accuracy rate of the algorithm.
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Computer Engineering. 2010, 36(13): 79-81. https://doi.org/10.3969/j.issn.1000-3428.2010.13.028This paper uses description logic as the theoretical basis of ontology standard language, studies the conception and goal of ontology evolution and proposes a framework of ontology evolution. On the basis of them, the process and implementation technique of ontology evolution are discussed, including the syntax and semantics of ontology evolution operation and ontology change execution algorithm. It validates the feasibility of the framework and algorithm through the experimental platform of Book-System ontology.
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Computer Engineering. 2010, 36(13): 82-83,86. https://doi.org/10.3969/j.issn.1000-3428.2010.13.029
The content-based dynamic load-balancing algorithm of Web server is researched. A new algorithm by combining the number of servers corresponding to the request type concerned and the K value of PICK-KX algorithm is developed based on the dynamic algorithm of load-balancing of Web server. Simulation tests show this type of algorithm achieves a better balance between higher cache hit rate and smaller servers’ load-calculation. Besides, Web server balanced by this algorithm can acknowledge more responses in limit cases.
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Computer Engineering. 2010, 36(13): 84-86. https://doi.org/10.3969/j.issn.1000-3428.2010.13.030In order to get better communities, the LSI method is used. Web page content and structure information are mined based on latent semantic, and the produced communities are integrated. Experimental results show that Web community integration algorithm of dual-view enhances semantic. The smaller communities is weakened. The results have higher accuracy than the ones based on a single link or content community mining algorithms. The search results have more remarkable improvement when user’s inputting keywords have not strong aspect-oriented purpose in information retrieval.
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Computer Engineering. 2010, 36(13): 87-89,92. https://doi.org/10.3969/j.issn.1000-3428.2010.13.031This paper proposes a XML data stream clustering algorithm SW-XSCLS, based on sliding window, in the view of the XML data stream clustering research. The algorithm uses the sliding window technology, takes Exponential Histogram of Clustering Feature(EHCF) as its summary of data structure, it can dynamicly eliminates the outdated data, better preservation of the data distribution in current window, so can obtain a higher quality of clustering results. Theoretical analysis and experimental result show that the algorithm can obtain the higher clustering quality and the quicker processing speed.
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Computer Engineering. 2010, 36(13): 90-92. https://doi.org/10.3969/j.issn.1000-3428.2010.13.032
A text classification approach based on soft set theory is proposed to enhance the accuracy of the text classification. The text training set is mapped onto a fuzzy soft set, the category of the new text can be achieved through the reduction of soft set table and construction of the comparison table of the soft set, in order to solve the problem that classification accuracy degrades when the feature is closely related to the selected feature, this paper gives a new feature selection algorithm based on normalization mutual information feature selection algorithm. Comparing with traditional KNN and SVM classification algorithm, the fuzzy soft set approach has the improvement on classification precision and accuracy.
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Computer Engineering. 2010, 36(13): 93-95. https://doi.org/10.3969/j.issn.1000-3428.2010.13.033Different storage models influence the performance of message oriented middleware a lot. This paper analyzes different kinds of storage model for message oriented middleware. The analysis is based on performance test on these models. Distributed cache has an advantage on the traditional store method on the data storage and the scalability. A storage model based on distributed cache is proposed based on the analysis. A prototype system is also built to evaluate this storage model. Evaluation shows this model improves the performance of message oriented middleware a lot.
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Computer Engineering. 2010, 36(13): 96-98. https://doi.org/10.3969/j.issn.1000-3428.2010.13.034This paper proposes an energy-saving routing protocol based on self-organized routing table SREP. Based on a self-organized routing table for each sensor node, the protocol uses hop counts and remaining energy as metrics to realize clustering and cluster head selecting, and cluster head transfer messages to the sink with multi-hop routing scheme. Simulation results demonstrate that compared with LEACH algorithm, the algorithm can balance the distribution of clusters, control the number of clusters in each round, and prolong the lifetime of WSN. And it can reduce the network delay compared with PEGASIS algorithm.
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Computer Engineering. 2010, 36(13): 99-101,104. https://doi.org/10.3969/j.issn.1000-3428.2010.13.035Aiming at the problem that the transmission efficiency of standard TCP services over narrowband wireless is low, this paper presents a channel match transmission method based on multi-algorithm selection l. It tags wireless channel performance with bandwidth, latency and loss rate, and selects corresponding congestion control algorithm to match various channels. Simulation result proves that the method can optimize transmission effects in wireless channels of 2 Kb/s, 20 Kb/s and 2 Mb/s, while the throughput increases by 120%~300% compared with standard TCP transmission.
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Computer Engineering. 2010, 36(13): 102-104. https://doi.org/10.3969/j.issn.1000-3428.2010.13.036The performance of traditional TCP protocol is much discounted over hybrid network. TCP Westwood(TCPW) protocol is an end-to-end solution based on bandwidth estimation. Aiming at the problem of inaccurate bandwidth estimation for TCPW protocol, this paper proposes a cross-layer optimized design, uses times of Request To Send(RTS) of Media Access Control(MAC) layer as a congestion metric. Simulation results show that this optimized design can improve performance of the total throughput and fairness respectively by 23.8% and 2.5% than TCPW protocol.
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Computer Engineering. 2010, 36(13): 105-107,110. https://doi.org/10.3969/j.issn.1000-3428.2010.13.037Connected dominating set is very important in Wireless Sensor Networks(WSN) as a virtual backbone for communication and routing between nodes. This paper proposes a nodes’ neighborhood based algorithm to construct a Minimum Connected Dominating Set(MCDS) in WSN. The complexities of time and message are O(nlogn) and O(n), respectively. Regarding to the topological changes due to power constraint, it presents a repair algorithm to reconstruct the MCDS. Theoretical analysis and simulations both demonstrate the correctness and performance of the algorithm.
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Computer Engineering. 2010, 36(13): 108-110. https://doi.org/10.3969/j.issn.1000-3428.2010.13.038The calling of users is very uneven and the channel collision detection ability is quite weak in Low Earth Orbit(LEO) satellite communication. To ensure quality of service, a novel Load Measurement Access Control(LMAC) protocol is proposed. The effect which the waiting probability of calling service, calling number and measure parameter on the performance of the networks are analyzed. Simulation experimental results show that the proposed access protocol is appropriate, and the LMAC protocol can simplify the description of special service.
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Computer Engineering. 2010, 36(13): 111-113. https://doi.org/10.3969/j.issn.1000-3428.2010.13.039In order to research performance of clustering algorithm in Wireless Sensor Network(WSN), this paper implements Hybrid Energy-Efficient Distributed clustering(HEED) algorithm on hardware platform using TinyOS operation system. It gives MAC protocol and routing protocol according to tree network topology after clustering. Experimental results demonstrate that HEED algorithm performs well in node uniformly distributing network, and HEED algorithm performs poor in node non-uniformly distributing network. The MAC protocol and routing protocol can ensure nodes have lower duty-cycle and consequently prolong the network lifetime.
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Computer Engineering. 2010, 36(13): 114-116. https://doi.org/10.3969/j.issn.1000-3428.2010.13.040In order to monitor the node in in-vehicle network in real time, this paper designs and implements in-vehicle Network Management(NM) system based on OSEK/VDX specification direct NM in in-vehicle network which using Controller Area Network(CAN) bus. The in-vehicle gateway collects information from the fault node, communicates with the remote fault diagnostic service through the IPv6 wireless network, sends the execute information from the service to the node, and implements the information exchange between the fault node and the remote fault diagnostic service. Text results show that network node after on line can quick build stable logical ring communication, and provide operation platform for remote fault diagnosis.
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Computer Engineering. 2010, 36(13): 117-119. https://doi.org/10.3969/j.issn.1000-3428.2010.13.041Low-cost shortest path tree is a widely used multicast tree, but often cannot meet the demand of delay constraint from source to destination end during information transmission in real-time multimedia application. Aiming at this problem, this paper presents a fast low-cost multicast routing algorithm based on delay-constrained. It uses cost to construct initial tree satisfied delay-constrained, and the path unsatisfied delay-constrained is substitute for minimum delay path. Simulation results show that this algorithm has less computation time and low multicast tree total cost than Delay-Constrained Shortest Path tree(DCSP) algorithm.
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Computer Engineering. 2010, 36(13): 120-121,124. https://doi.org/10.3969/j.issn.1000-3428.2010.13.042In order to solve the unstable performance of TCP in wireless network or the heterogeneous network, this paper presents a packet error detection mechanism based on Vegas protocol. It extends TCP Vegas header option and allows the receiver to return a special ACK generated in response to packet corruption. It holds peer-to-peer semantic of TCP Vegas protocol, need not mend base station or middle node. NS2 simulation experimental shows that distinguish packet corruption from congestion, avoid lots of unwanted timeouts caused by retransmitted packet to be corrupted and hence, and enhances transmission performance.
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Computer Engineering. 2010, 36(13): 122-124. https://doi.org/10.3969/j.issn.1000-3428.2010.13.043Enhanced Distributed Channel Access(EDCA) of Wireless Local Area Network(WLAN) can support multi-class traffic. In order to reveal the essence of EDCA mechanism, a bi-dimensional Markov model is proposed to depict the EDCA scheme under finite load. The proposed model employs idle and post backoff states to deduce the channel throughput under both unsaturation case and saturation case, which also considers all characteristics of IEEE 802.11e EDCA, including the retransmissions, post-collision process. Simulation results show the accuracy of the proposed model. The results also reveal that the maximum throughput is achieved at the unsaturation case.
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Computer Engineering. 2010, 36(13): 125-127. https://doi.org/10.3969/j.issn.1000-3428.2010.13.044A radix-4 Montgomery modular multiplication and the optimized circuit architecture are presented. It can reduce iterations of traditional radix-2 modular multiplication to about 50%. Based on this module, the implementation of high speed RSA encryption processor follows completely parallel modular exponentiation flow with Carry Save Addition(CSA) structure to perform long integer arithmetic. This avoids the repeated interim output/output format conversion. Result shows that the optimization is technology independent and thus should suit well for not only FPGA implementation but also ASIC. This design can complete a standard 1 024 bit RSA encrypt operation with only 9 836 clock cycles. Compared to the recently proposed design in the literature, the proposed design can achieve an increase of over 50% in throughput.
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Computer Engineering. 2010, 36(13): 128-130. https://doi.org/10.3969/j.issn.1000-3428.2010.13.045A novel watermark method based on the texture of image is proposed. In the finest directional subband of the nonsubsampled Contourlet transform, the coordinate of the coefficient with the richest texture feature by using Canny operator is selected as the index coordinate to be embedded watermark. The three subbands are obtained by applying DWT to the low frequency subband and divided into N circuses which are as many as the pixels of watermark image. Watermark is done by altering the coefficients of the subbands, and every bit of the watermark is inserted repeatedly in a cirque area. Experimental results show the proposed algorithm has good transparency and is very robust to common image processing and geometric attacks.
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Computer Engineering. 2010, 36(13): 131-133. https://doi.org/10.3969/j.issn.1000-3428.2010.13.046Constructing a Boolean function on odd variables for the maximum algebraic immunity is equivalent to finding an invertible submatrix in a given matrix. However, how to find invertible submatrixes efficiently in the matrix remains a problem. In order to solve the problem, the matrix is further studied. The description of the matrix is simplified, and several constructions of Boolean functions on odd variables for the maximum algebraic immunity are introduced. With these constructions, more Boolean functions on odd variables with the maximum algebraic immunity can be efficiently constructed, since one only needs some operations on vectors of low dimension and avoids deciding the invertibility of submatrixes.
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Computer Engineering. 2010, 36(13): 134-136. https://doi.org/10.3969/j.issn.1000-3428.2010.13.047This paper analyzes the structure of the cluster firewall system and data packets negotiation treatment, and proposes a Cluster Firewall System(CFS) load-balancing algorithm based on negotiation treatment. The algorithm achieves parallel filter data based on the weighted Hash algorithm. When a firewall overloads, it transfers some assignments to the light-load partners nodes. When a firewall is failure, the backup firewall fast replaces the failure firewall. The algorithm can achieve a firewall node’s load-balancing, the more firewall number, the more higher throughput, the lower latency. And high performance, high reliability and high availability are received.
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Computer Engineering. 2010, 36(13): 137-139. https://doi.org/10.3969/j.issn.1000-3428.2010.13.048With the rapid increase of the enterprise users, it is a tiresome task for the system administrator to assign roles and maintain permissions in traditional Role-Based Access Control(RBAC) strategy. In order to simplify the administrator’s work and standardize security strategy, an optimized RBAC model based on fuzzy is proposed. Bitmap matrix is used for computing role’s trustworthiness. Variance is applied to adjust attribute weight vector to improve max-min operation’s limitation. By clustering similar users, group experience is shared among the users within the same cluster to improve the accuracy of the model. A fuzzy RBAC model with separation of duty constraint is implemented by enforcing a historical, mutual exclusive permission table for each user.
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Computer Engineering. 2010, 36(13): 140-142. https://doi.org/10.3969/j.issn.1000-3428.2010.13.049This paper proposes a network border security monitor method based on Public Key Infrastructure(PKI) according to the requirement and characteristic of network border security protection. The technique combines identity authentication mechanism based on PKI, intrusion detection technology and VPN technology. It can accurately locate the origin of intrusion and prevent attacks soon after real-time detection of intrusion behaviors via association analysis of network traffic and system log. As a result, it has higher accuracy and usability than general signature detection and abnormal detection technique.
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Computer Engineering. 2010, 36(13): 143-145. https://doi.org/10.3969/j.issn.1000-3428.2010.13.050This paper analyzes the advantages and disadvantages of various traditional scalar multiplication algorithms for elliptic curve. It introduces a scalar dynamic encoding method——MOF encoding. Based on the work above, it puts forward and realizes a scalar multiplication scheme associated with MOF encoding. This paper makes a comparison of the ECC IP before and after improvement in both area and performance aspects. Experimental results show that this scheme can efficiently save memory at no cost of performance. It is suitable for implementation in resource constrained mobile equipments such as smart card.
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Computer Engineering. 2010, 36(13): 146-148. https://doi.org/10.3969/j.issn.1000-3428.2010.13.051This paper proposes a novel scheme aiming at security treatments based on Kerberos protocol with Single Sign-On(SOS) in Web environment. In order to avoid authentication server being attacked, a challenge/response mode with Schnorr protocol is adopted. Secure cookies and HTTP session are selected to solve HTTP protocol non-state, and to keep secure sessions between Web servers. Experimental test shows that this project has solid performance, fast response speed, strong resistibility, and possesses better application value and foreground.
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Computer Engineering. 2010, 36(13): 149-150,153. https://doi.org/10.3969/j.issn.1000-3428.2010.13.052A DFA-based grammar model for detecting cyber attacks is proposed. Normal network behavior tends to follow regular grammar rules, while anomalies tend to deviate. The DFA-based model trained with normal network flow enables the efficient detection of cyber attacks against Web servers. The experiments based on real Web site data show its good detection performance.
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Computer Engineering. 2010, 36(13): 151-153. https://doi.org/10.3969/j.issn.1000-3428.2010.13.053A flexible scheme of Simple Object Access Protocol(SOAP) message signature encryption is designed for the purpose of separating its functional logic design from non-functional security design. While enhancing the maintainability and scalability of the system, a part of the SOAP message signature encryption is realized. The scheme is implemented with WSE 3.0 in .NET, which proves that it has high application value.
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Computer Engineering. 2010, 36(13): 154-155,158. https://doi.org/10.3969/j.issn.1000-3428.2010.13.054An identity authentication protocol and a message authentication protocol based on non-homogeneous linear equation proposed by Liu Li and two other co-authors(Journal of Academy of Armored Force Engineering, 2005, No.2) uses a single authentication protocol which can not resist the pseudo-sever attack, and can be only applied in computer network communication system of fixed terminal. To solve the problem, this paper proposes an improved scheme: a mutual authentication protocol by using RSA arithmetic at the convenience of user authentication and security. The new scheme can conquer the security problem of the original scheme and hold higher security and operability.
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Computer Engineering. 2010, 36(13): 156-158. https://doi.org/10.3969/j.issn.1000-3428.2010.13.055Elliptic curve cryptosystem is known as its unique advantages of high security, small amount of key and flexibility. Based on elliptic curve digital signature which provides security in many electronic commerce areas such as authentication, data integrity, non-repudiation and the anonymity, this paper proposes a blind digital signature based on the finite field GF(p) on non-supersingular elliptic curve, and designs an online e-voting protocol which is in conjunction with this program. Its safety is dependent on the discrete logarithm of elliptic curve, and it is suitable for some practice.
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Computer Engineering. 2010, 36(13): 159-161. https://doi.org/10.3969/j.issn.1000-3428.2010.13.056This paper proposes an improved level set segmentation algorithm based on skin color feature to implement accurate hand contour segmentation from clutter background. It introduces the deduction and implementation of the proposed total algorithm. When applying the improved algorithm to hand tracking, the location and size of hand obtained by particle filter is taken to initial the level set function, which can speed up the convergence speed of curve iteration. The extracting contour is used to locate fingertips. Experimental result shows that the algorithm can track accurate hand contour and fingertips from clutter background in real-time.
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Computer Engineering. 2010, 36(13): 162-163,166. https://doi.org/10.3969/j.issn.1000-3428.2010.13.057This paper compares several partition methods, and discusses their disadvantages in application to metabolic networks. Simulated Annealing Algorithm(SAA) is more appropriate for identifying modules in metabolic networks, and is engaged for decomposing the giant strong component of B. thuringiensis metabolic network. By comparing to pathway information in KEGG, it finds that most of decomposed modules are according to 1~2 KEGG pathways. It suggests that these modules are biologically functional significant.
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Computer Engineering. 2010, 36(13): 164-166. https://doi.org/10.3969/j.issn.1000-3428.2010.13.058Aiming at the problem that changing preferences is very common, this paper proposes the operation of discarding preferences——preference contraction. The property of minimality and the preservation of strict partial orders are crucial for contractions. It presents framework which can deal with finite as well as infinite preference relations. It gives algorithms for computing contractions for preference relations. It computes full contractor of a preference relation by base contractors to preserve strict partial orders in the modified preference relation. It minimizes the full contractor, and obtains the modified full contractor. Simulation results show that the size of full contractor after revision is obvious smaller than before.
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Computer Engineering. 2010, 36(13): 167-169,172. https://doi.org/10.3969/j.issn.1000-3428.2010.13.059Aiming at the problem of current expert system about imprecise semantic representation of domain knowledge and low reasoning efficiency, an Ontology-based expert system framework is proposed. In accordance with rule structure, rule pattern Ontology and action Ontology are created. User reasoning conditions are transformed into sub-pattern Ontology, and then a reasoning algorithm of expert system based on similarity calculation based on name and instance as well as Clips reasoning mechanism is designed. An application example from high performance machining is given. Experimental results show that the system can obviously improve reasoning efficiency and semantic expression of reasoning conclusions.
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Computer Engineering. 2010, 36(13): 170-172. https://doi.org/10.3969/j.issn.1000-3428.2010.13.060A novel steganalysis method is proposed on the basis of 2-D Hidden Markov Model(HMM) in wavelet domain which is employed to describe the statistics of wavelet coefficients precisely. By modeling wavelet coefficient with 2-D wavelet HMM, classification features are constructed based on parameter sets of HMT forests. Experiments show the technology is applicable for the detection of wavelet domain steganography, especially with higher detecting performance for QIM, MFP, BPCS steganography in wavelet domain.
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Computer Engineering. 2010, 36(13): 173-174,177. https://doi.org/10.3969/j.issn.1000-3428.2010.13.061According to the demand of the high distinctive face features for face recognition, this paper proposes an improved algorithm based on Scale Invariant Feature Transform(SIFT) descriptor combined with a pattern matching strategy of K-means clustering for face recognition, it adopts the local and global similarity to calculate the matching for face images, and makes use of the square of similarity and the weight assignment solution based on probability statistics to improve accuracy in local feature matching. Experimental results show the robustness and effectiveness of the method.
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Computer Engineering. 2010, 36(13): 175-177. https://doi.org/10.3969/j.issn.1000-3428.2010.13.062Aiming at the problem of Quantum Genetic Algorithm(QGA) exists easily getting into local minimum. this paper presents a fuzzy QGA. It adopts a mutative scale chaos optimization method. The method has nested iterations, the inner is used for chaos search and the outer is used to reduce the range. The blind repeated search of chaos optimization in search space can be avoided through ameliorating its constringency strategy. Chaotic search for the optimization using this chaos optimization method is implemented towards the population produced by the quantum genetic algorithm, and fuzzy control is updated the population in order to speed the evolution of the population. Simulation results show that this algorithm is more effective than QGA and genetic algorithm.
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Computer Engineering. 2010, 36(13): 178-179,182. https://doi.org/10.3969/j.issn.1000-3428.2010.13.063The decision-making of robots walks path is a difficult researching project. It must judge the environment accurately and determine the correct walks path, which requires algorithm to have certain compatibility and the fast computing power. This paper proposes a path planning algorithm in the basis of A* algorithm. It changes the shortcoming that A* algorithm can not generate smooth change path, and it takes a little time cost. This algorithm may be suitable in promptly analyzing environment about the robot in moving.
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Computer Engineering. 2010, 36(13): 180-182. https://doi.org/10.3969/j.issn.1000-3428.2010.13.064This paper proposes a voice and Voice Band Data(VBD) classification method based on selective ensemble Support Vector Machine(SVM). According to a difference definition of ensemble algorithm, the classifier output is completed by two level structure’s dynamic stacking algorithm. In the training stage, the method can choose accurately the number classifiers which have the high recognition precision and the difference. In the test stage, a dynamic ensemble algorithm is used to guarantee that the final classified result is most superior. In the characteristic parameters extraction, the character vector is built that includes the time domain and the frequency domain character. These parameters have good anti-noise ability. Experimental results show that the algorithm that is proposed in the method has good classification effect and low operation complexity.
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Computer Engineering. 2010, 36(13): 183-185. https://doi.org/10.3969/j.issn.1000-3428.2010.13.065Aiming at the problems in Super-Resolution(SR) reconstruction of single Low-Resolution(LR) image, an improved local-adaptation interpolation method based on wavelet transform for image SR reconstruction is proposed. The method makes up for the shortcomings of that the edge of the reconstruction image is not smooth enough, and it maintains the edge and details of images. Combined with the characteristics of that wavelet transform can separate high and low frequency information. The single image SR reconstruction algorithm combined with the advantages of them is presented. Experimental results show the reconstructed image using this method can not only maintain the details information of original image very well, improve the image spatial resolution, but also improve the Peak Signal Noise Ratio(PSNR) of image. It is more suitable for human visual system.
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Computer Engineering. 2010, 36(13): 186-188. https://doi.org/10.3969/j.issn.1000-3428.2010.13.066In order to solve the problem of lacking the spatial knowledge of color histogram, an approach of image retrieval based on dominant color of partition is presented. It designs overlapped sub-blocks to get the color accumulative histogram in each block. Meanwhile, the reduced quadratic form distance method is applied to decrease arithmetic complexity. The similarity is calculated based on the accumulative histogram of each region. Experimental results show the algorithm can greatly reduce the dimension of color feature, and keep high retrieval precision simultaneity.
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Computer Engineering. 2010, 36(13): 189-191. https://doi.org/10.3969/j.issn.1000-3428.2010.13.067The quality of inpainting using a single dictionary is not so good that an image inpainting algorithm based on three-layer sparse representation is proposed. The algorithm makes use of discrete stationary wavelet, curvelet and wave atoms to implement sparse representation of smooth, edge and texture component respectively. Applying the block coordinate relaxation methods to solve the corresponding sparse optimization problem, the damaged image can be inpainted. Experimental results show that the algorithm can recover multiple structural components of the image and improve the quality effectively.
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Computer Engineering. 2010, 36(13): 192-193,196. https://doi.org/10.3969/j.issn.1000-3428.2010.13.068Color image with complicated texture is insufficiently dealt with a traditional seed region growth method. Aiming at this problem, an improved seeded region growth method to segment color image is presented. The research is based on YCbCr model. The texture features are obtained by discrete cosine transform. The seeds and seeded region are produced automatically. The region-merging is used to improve the image segmentation result. Experimental results show the algorithm can effectively improve segmentation accuracy for different image natures.
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Computer Engineering. 2010, 36(13): 194-196. https://doi.org/10.3969/j.issn.1000-3428.2010.13.069A novel mesh reconstruction algorithm using point cloud is presented. The proposed algorithm is based on geometric and shape feature of point cloud. The points are classified according to their geometric distribution, and they are classified according to the local shape feature. The mesh reconstruction is done on different type of points. A post-processing is performed to repair the topological and geometric errors. Experimental results show this algorithm is robust and effective. High quality meshes can be created while geometric and shape features are well preserved.
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Computer Engineering. 2010, 36(13): 197-198,204. https://doi.org/10.3969/j.issn.1000-3428.2010.13.070To improve the readability of the image and ameliorate image quality, this paper proposes a fused denoising algorithm of the polarized SAR image based on maximize Signal To Noise Ratio(SNR). According to meet the requirement of getting the largest SNR at the image filtering, this method uses the smallest mean square error as the convergent condition. It filters and fuses in two directions of the polarized SAR images respectively. Compared with the traditional Lee filtered algorithm and adaptive threshold algorithm, the algorithm has higher performance.
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Computer Engineering. 2010, 36(13): 199-200,204. https://doi.org/10.3969/j.issn.1000-3428.2010.13.071For its good property of pulse burst, Pulse Coupled Neural Network(PCNN) is widely used in image segmentation. However, there are such problems in the method as its parameters are decided by experiment, so use the contrast of pixels as model’s link matrix, and use image mutual information entropy as the criterion to terminate iteration to modify standard model. This paper proposes an automated image segmentation based on modified PCNN. Experimental results show that the method is adaptive, its real time ability is good, and target contour is more clear.
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Computer Engineering. 2010, 36(13): 201-204. https://doi.org/10.3969/j.issn.1000-3428.2010.13.072The system bottleneck caused by bus bandwidth and memory space can be encountered until the stage of register transfer level coding design, and that will increase the design iteration. Aiming at this problem, budgeting technique for system resources is used. This paper aims to decide the parameters of Asynchronous Transfer Mode(ATM) switch chip based on hardware resource occupied during the process of switch. Simulation and hardware test results indicate the ATM switch chip can meet the system’s requirements.
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Computer Engineering. 2010, 36(13): 205-207. https://doi.org/10.3969/j.issn.1000-3428.2010.13.073This paper introduces a switched hyperchaotic system that converts its states from one subsystem to another via two switch functions. The basic dynamic characteristics, such as symmetry, dissipation, equilibrium, stability, bifurcation diagram and Lyapunov exponent spectrum of this system are analyzed. The system is implemented by FPGA hardware. It is shown that the experimental results are identical with numerical simulations.
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Computer Engineering. 2010, 36(13): 208-210. https://doi.org/10.3969/j.issn.1000-3428.2010.13.074A two-process control method is introduced in changing the old level crossing system. The computer simulated data are analyzed and compared with main performance figures in the new and original system. The two-process method system types can be used for many complex or special city environment. The whole computer control system is discussed with its construction, which can control the vehicle and pedestrian passing. Application results show this mode has the function to reduce the city traffic jams and raise the road traffic.
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Computer Engineering. 2010, 36(13): 211-212,215. https://doi.org/10.3969/j.issn.1000-3428.2010.13.075According to the method of CPU chip application validation, this paper presents the test process and design of hardware platform used for SM8260 Cache application validation in write-through mode. It analyzes the initial process of SM8260 L1 Cache and L2 Cache, carries out benchmark tests and large array tests on write-through mode. Test results indicate that the use of L2 Cache can improve system performance in embedded system to some extent in the case of large array.
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Computer Engineering. 2010, 36(13): 213-215. https://doi.org/10.3969/j.issn.1000-3428.2010.13.076This paper puts forward a general design scheme of wireless automatic picture taking terminal, and develops the wireless automatic picture taking terminal by GPRS wireless communication technology and computer technology. The terminal hardware is designed by AT91RM9200 embedded micro-processor and GPRS wireless communication module. The platform of embedded Linux operating system is built, and PPP protocol is porting. The application program is developed by multi-threads, which includes GPRS wireless communication software using PPP and TCP protocol. The terminal is debugged and tested.
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Computer Engineering. 2010, 36(13): 216-218,221. https://doi.org/10.3969/j.issn.1000-3428.2010.13.077According to the hair oil incorporate requirement for making out invoices, stowage and settlement, this paper puts forward the multi-tier software structure based on OPC and Web Service technology, and develops the application software. The structure makes up for defects of the previous oil delivery software, such as bad real-time and resuability, and fulfils actual requirement of the large-scale oil depot. Pratices show the structure is effective.
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Computer Engineering. 2010, 36(13): 219-221. https://doi.org/10.3969/j.issn.1000-3428.2010.13.078This paper expatiates the principle of secondary Bootloader and uses Complex Programmable Logic Device(CPLD) for logic decoding. It controls the pagination of Flash space to complete the second address mapping. The linker command options are used to create boot table and the secondary Bootloader for large-scale program code is designed. Test results indicate that this method can complete the secondary Bootloader for codes with 2 MB or larger scale and lay a good foundation for software development of large-scale embedded systems.
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Computer Engineering. 2010, 36(13): 222-223,226. https://doi.org/10.3969/j.issn.1000-3428.2010.13.079This paper introduces a system that includes two ADC0809 and one 51 SCM. This system adopts a method that connects ADC0809 with SCM only by circuits. Compared with the existing methods, it has a lot of advantages, such as simple circuit, low cost, easy programming, steady signal and so on. This method can realize the real-time data acquisition function of 16 channels and more channels. Experimental results show the system has a high collecting accuracy, and a wide acquisition frequency and a high gathering speed.
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Computer Engineering. 2010, 36(13): 224-226. https://doi.org/10.3969/j.issn.1000-3428.2010.13.080By studying the statistical characteristics and modeling method of the synchronous satellite communication channel at Ka-band and the rainfall influence on the performance of the system, this paper constructs a simulation platform of the digital satellite broadcasting system based on DVB-S standard which works at Ka-band. BER of the system in different climate conditions is simulated and analyzed on the platform, and the results show that the black cloud climate has the worst influence on the performance of the system. The system increases the performance by 9 dB compared with the system without channel coding.
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Computer Engineering. 2010, 36(13): 227-229. https://doi.org/10.3969/j.issn.1000-3428.2010.13.081Aiming at two-dimensional cutting stock problem of circular items, this paper presents an improved Sequential Heuristic Procedure(SHP). In the process of generating cutting patterns, Sequential Value Correction(SVC) strategy is used to update the value of circular items contained in the current pattern, making them more reasonable. The pattern with maximum value is selected to form the current cutting plan. Several solutions are constructed iteratively to select the best one. Experimental result proves that compared with LP algorithm, the algorithm is more effective.
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Computer Engineering. 2010, 36(13): 230-235. https://doi.org/10.3969/j.issn.1000-3428.2010.13.082According to different acharacteristics of software reliability and hardware reliability, this paper discusses the current developping status about fault-tolerance technology, and analyzes various ideas and strategies of fault-tolerance methods in computer systems including redundance, error rollback recovery mechanism and generalized fault-tolerant design method etc. Some defects and key issues for some existed fault-tolerance methods on reaction delay, fault-tolerance cost, precise quantification, heterogeneous synchronous, reliability modeling are pointed out. How to improve and use these methods better is suggested.
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Computer Engineering. 2010, 36(13): 236-238. https://doi.org/10.3969/j.issn.1000-3428.2010.13.083In order to solve the professional and complexity in currently Computer Aided Design(CAD) interface, this paper transforms two-dimensional operation to three-dimensional environment by using augmented reality technology. It looks for the coordinate presentation method for space situation point in world coordinate system by mutual relations in camera, interaction tool and reference mark. Experimental result indicates that the method has good stability and feasibility and can satisfy the requirement of interactive modeling.
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Computer Engineering. 2010, 36(13): 239-241. https://doi.org/10.3969/j.issn.1000-3428.2010.13.084On the basis of Cooperative Task Simulation Model(CTSM), this paper proposes a cognitive cooperation walkthrough inspection technology, and designs its walkthrough process algorithm. The first stage comparison experiment validates that the usability evaluation technology is suitable for cooperation software system at early design, and it achieves low cost and high efficiency. The number of evaluators is increased in the second-stage experiment. How the quantity and individual performance of evaluator affect the evaluations result is analyzed. The number of samples to gain the highest cost-effective ratio for general evaluation is suggested.
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Computer Engineering. 2010, 36(13): 242-244. https://doi.org/10.3969/j.issn.1000-3428.2010.13.085Aiming at the problem that hidden resources may exist in the procedure of resource reservation processing, this paper proposes a resource reservation rate adjustment mechanism based on arrival rate measurement. When the divergence of a flow’s arrival rate and reservation rate goes beyond the threshold set by the network manager, the reservation rate of the flow is set to its arrival rate. Little time scale average rate estimation based on rate envelope is adopted for the arrival rate measurement and the traffic similarity is considered. Simulation results show that the mechanism can effectively deal with the hidden resource problem and achieve high resource utilization rate.
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Computer Engineering. 2010, 36(13): 245-247. https://doi.org/10.3969/j.issn.1000-3428.2010.13.086Aiming at function optimization problem, by analyzing the influence of two key parameters(harmony pitch adjusting rate and harmony bandwidth) on search performance of Harmony Search(HS) algorithm, this paper proposes dynamic changing methods for harmony pitch adjusting rate and harmony bandwidth during the search, and obtains nine improved harmony search algorithms. Experimental results show that compared with M_IHS algorithm, the improved algorithms have higher optimization performance.
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Computer Engineering. 2010, 36(13): 248-250,253. https://doi.org/10.3969/j.issn.1000-3428.2010.13.087According to the characteristics of navy joint operation simulation and the requirements of effective multi-resolution modeling, a warship model of operation simulation is constructed based on multi-representation. The composition of the fleet-warship Multi-representation Entity(MRE) is presented. The attribute dependency graph is described and mapping functions are selected to maintain consistency among the representations in fleet-warship MRE. On the basis of classifying the interactions, the policies of resolving conflicts between concurrent interactions are presented. The application of the warship model based on multi-representation shows that the model can satisfy the requirements for navy joint operation simulation.
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Computer Engineering. 2010, 36(13): 251-253. https://doi.org/10.3969/j.issn.1000-3428.2010.13.088For single processor system control of wireless communication system in small soccer robot competition existing packet loss, poor real-time, this paper puts forward a kind of Field Programmable Gate Array(FPGA) parallel control module to achieve full-duplex communication. including data of wireless transmitting and receiving module, and the data packet processing, using finite state machine design timing of transmitting and receiving. Results show that this scheme has high stability and flexibility, real-time.
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Computer Engineering. 2010, 36(13): 254-256,259. https://doi.org/10.3969/j.issn.1000-3428.2010.13.089Aiming at the lack of adaptive faculty and the robustness of Augmented Reality(AR) of tracking and registration based on marker, this paper presents an improved algorithm of the marker’s tracking registration using SURF. The algorithm detects and describes the feature points of a plane marker through SURF, gets the clustering centers of the detected feature points of the marker by K-Means, combines threshold segmentation with connected component analysis to construct coordinates of SURF feature points, and realizes the tracking registration of the marker by means of matrix transformation. Experimental results show the robustness, stability and real-time of the AR system based on the improved algorithm.
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Computer Engineering. 2010, 36(13): 257-259. https://doi.org/10.3969/j.issn.1000-3428.2010.13.090This paper analyzes Mutual Information(MI) theory. According to deficiency of MI, rough set is introduced and an attribute reduction algorithm based on attribute union theory is proposed. A feature selection method based on MI and attribute union theory is presented which is suitable for massive text data sets. The method uses MI to select features, and employs the proposed attribute reduction algorithm to eliminate redundancy, so the feature subsets which are more representative can be acquired. Experimental results show that the method is effective.
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Computer Engineering. 2010, 36(13): 260-262. https://doi.org/10.3969/j.issn.1000-3428.2010.13.091For the deficiency of flexibility and security in today’s workflow management system, this paper proposes a task delegation model, which is characterized by temporariness, single-step, monotonicity, agreement, symmetry, etc. It specifies the delegation relationship, delegation condition, delegation prescription as well as the whole delegation process from implement ation to revoking. Therefore, the blocking problem in workflows caused by executor’s being unable to implement his/her tasks in time can be solved and the efficiency of the whole system can be greatly improved.
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Computer Engineering. 2010, 36(13): 263-264,268. https://doi.org/10.3969/j.issn.1000-3428.2010.13.092When the first number in μ-patterns of weakly hard real-time system is 0, the constraint specification will be invalid. This paper puts forward a new constraint specification to solve the problem by changing the computing method of meeting the rate of deadline. The new constraint specification not only retains the advantages of but also widens the scope of its usage. The high performance is verified by proof of partial order.
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Computer Engineering. 2010, 36(13): 265-268. https://doi.org/10.3969/j.issn.1000-3428.2010.13.093This paper analyzes the dynamic voltage scaling prediction algorithm, a Dynamic Voltage Scaling(DVS) prediction algorithm based on Cycle Mode Matching(CMM) is proposed to improve the accuracy of DVS prediction. Simulation result shows that, to different test sets, the accuracy of DVS prediction is improved from 4% to 15% using CMM without the perceptible impact of system performance.
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Computer Engineering. 2010, 36(13): 269-271,275. https://doi.org/10.3969/j.issn.1000-3428.2010.13.094By analyzing the combination of Diameter protocol and Protocol for carrying Authentication for Network Access(PANA) in directions of working model and protocol structure, this paper puts forward a complete solution combining the two protocols, which includes the key device architecture and an implementation method based on Open Diameter. Experimental result proves that the solution can meet the complex requirements of Authentication, Authorization, Accounting(AAA) in network system.
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Computer Engineering. 2010, 36(13): 272-275. https://doi.org/10.3969/j.issn.1000-3428.2010.13.095This paper provides the evaluation model and system running through the full lifecycle of regional information by applying the analysis of the characteristics of data warehouse data model, using multi-indicator hierarchical comprehensive evaluation algorithm to get the comprehensive evaluation results of information level, establishing fuzzy evaluation matrix and setting the weight coefficient. Result of integrated evaluation of regional informatization is gained in the evaluation process that runs from the low level to the high level. Results prove the superiority and universal applicability of this method.
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Computer Engineering. 2010, 36(13): 276-277,280. https://doi.org/10.3969/j.issn.1000-3428.2010.13.096In computer application system, aiming at the problem of single 01 ary existing information sharing and cracking easily, this paper presents a special number theory and the design theory of special binary computer by combinating the charactertics of common binary and common binary computer. Results show that this coding theory can better solve information security problem in computer application system by changing the code system and the logical relationship between the digital. It provides a theoretical basis for implement ation of special binary computer.
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Computer Engineering. 2010, 36(13): 278-280. https://doi.org/10.3969/j.issn.1000-3428.2010.13.097To well take the advantage of performance of multi-core processor, aiming at hierarchical Network on Chip(NoC) architecture, this paper presents the MPI/OpenMP hybrid parallel programming model. The model uses MPI-based task-level parallel model to achieve efficient communication between clusters. It uses OpenMP method to implement communication, synchronization and data exchange between four cores inside clusters. Experimental results show that the model can increase the speedup by 20% to 50% compared to the single parallel programming model.
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Computer Engineering. 2010, 36(13): 281-283. https://doi.org/10.3969/j.issn.1000-3428.2010.13.098On the basis of aspect-oriented software design method, this paper takes time characteristics of distributed system as a separate aspect to modeling, imports the idea of time sub-aspect into Unified Modeling Language(UML), extends constraint by SQTL and Fuzzy-timing Petri Net(FTN). Example proves that this modeling method can solve the semantic problem and make the model more accurate, it is also convenient for the code weaving, automatic generation and testing.
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Computer Engineering. 2010, 36(13): 283-285. https://doi.org/10.3969/j.issn.1000-3428.2010.13.099In order to realize real-time transmission and effective display of the terrain landscape data, based on the requirement of different view field of high altitude and surface, this paper presents a terrain data stream transmission strategy based on visibility clipping, it can efficiently determine the visibility of view field and the Level Of Detail(LOD) of key node when position of vision moving. Experimental results show that the terrain data processed by the server can be rapidly transmitted to the client for accurate display.
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Computer Engineering. 2010, 36(13): 286-287,290. https://doi.org/10.3969/j.issn.1000-3428.2010.13.100Flagged prefix adder has fast operation speed, but it has the disadvantage of large area. In order to meet the requirement of floating-point multiply and add cellar area for practical application, this paper gets 51 bit flagged prefix adder based on Kogge-stone tree structure by optimizing its structure. It uses module cascading to reduce the number of operation unit, attains the goal of reducing floating-point multiply, adding cellar area and decreasing power consumption. Under TMSC 0.18 μm technology, area, power and key path delay of this 51 bit adder are decreased respectively by 10%, 10.5% and 6.4%.
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Computer Engineering. 2010, 36(13): 288-290. https://doi.org/10.3969/j.issn.1000-3428.2010.13.101
This paper explores both rules and guidance for look and feel, and interactive functionalities. It also introduces basic Interactive Electrical Technical Manual(IETM) concept which is supported in S1000D. The IETM’s viewer is designed according to the S1000D standards. The method of invoking Web Services from client-side script can dynamically update only specific content on a page without having to refresh the whole thing. This IETM’s viewer is successfully applied in several IETM systems. It implements a flexible interface and provides a rich user experience that is supported across all major viewers.
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Computer Engineering. 2010, 36(13): 291-封三. https://doi.org/10.3969/j.issn.1000-3428.2010.13.102This paper proposes an improved logic analysis method based on Qing-Zhou logic to analyze the security of electronic commerce protocols such as accountability, fairness and atomicity. By introducing the fresh property of the message, it make a message replayed can be recognized. And it redefines the realization of accountability, so that it can correctly analyze the property when the replay attack occurs. It gives atomicity goal and increases the method for atomicity analysis to analyze atomicity of electronic commerce protocols.
2024
Volume 50 No 3
Volume 50 No 3
(Started in 1975, Monthly)
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428