05 December 2011, Volume 37 Issue 23
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Computer Engineering. 2011, 37(23): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2011.23.001Aiming at the security deficiency of the pre-distribution scheme for Heterogeneous Sensor Network(HSN), a security pairwise key establishment scheme based on key chain and deployment knowledge is proposed for HSN. The deployment area is divided into multiple cells, the HSN is divided into multiple clusters. Two nodes whose deployment cells are adjacent can establish a common key by using pre-distribution keys. After deployment, if two neighboring nodes can not establish a common key, the common key must be distributed by other high energy node. Theory analysis and simulation results show that the scheme makes much more improvement than the classical scheme for HSN on the memory overhead, the local connectivity rate, the resilience against node capture.
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Computer Engineering. 2011, 37(23): 4-7. https://doi.org/10.3969/j.issn.1000-3428.2011.23.002Traditional 3D pipe path planning algorithm has the shortcomings that the grid modeling must take huge storage space for a long time and the search efficiency of Ant Colony System(ACA) is low. This paper proposes a routing algorithm based on octree modeling and modified ACA. It adopts octree model to model environment, generates the primary route through dynamic heuristic information, rationalizes the path selection mechanism, and updates the pheromone of the former w and the latter h, so that the storage space is reduced and excessive use of search rules is avoided. Simulation results show that the algorithm is effective and feasible.
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Computer Engineering. 2011, 37(23): 8-9,13. https://doi.org/10.3969/j.issn.1000-3428.2011.23.003In the publish/subscribe system based on content, each subscription usually contains certain attributes, and some properties of the subscription often appears at the same time. According to the situation, on the basis of a single multi-dimensional structure and multiple single-dimensional structures, this paper proposes a matching structure based on attribute grouping. Attribute grouping divides the attributes in the event scheme into several groups, each contains attributes that appear together frequently in the subscriptions. It designs indexing structures and construct overlays based on attribute grouping. Experimental results show that matching structure can achieve better balance between the bandwidth cost and the storage load.
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Computer Engineering. 2011, 37(23): 10-13. https://doi.org/10.3969/j.issn.1000-3428.2011.23.004This paper classifies the researches about train operation schedule according to two aspects of train operation diagram preparation and train operation adjustment. The train operation diagram preparation problems of the single two-lane section and the dedicated passenger line are presented. The train operation real-time adjustment, adding(canceling) additional train services and conflict prediction schemes are introduced. The importance of researching real-time and intelligence properties of the automatic schedule system, the evacuation of the trains under emergency conditions and the train operation schedule in the peak holiday situations are discussed.
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Computer Engineering. 2011, 37(23): 14-16,23. https://doi.org/10.3969/j.issn.1000-3428.2011.23.005In order to improve channel capacity and energy efficiency in emergency communication system, a cooperative relay selection and power allocation for joint optimization algorithm is presented. In the dynamic communications environment, it improves communication system channel capacity by selecting the best hope of collaboration in relay set. To minimize user and the whole network energy consumption, through the use of convex optimization methods, a reasonable distribution of the source node and a reasonable number of relay nodes between reasonable transmission power are done. Theoretical analysis and simulation experiments show that the proposed algorithm with lower complexity significantly improves the system's channel capacity and energy efficiency.
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Computer Engineering. 2011, 37(23): 17-19,26. https://doi.org/10.3969/j.issn.1000-3428.2011.23.006This paper presents a layered network structure merging with Wireless Sensor Network(WSN), General Packet Radio Service(GPRS) network and Internet to intelligently monitor the safety of the pipeline laid in remote station. WSN is build up based on WIA-PA industrial wireless standard. Clustered topology management is optimized, a low-power uplink protocol with extended super-frame for assigning timeslot is proposed, and an on-time downlink protocol of attaching timestamp to flooding protocol is implemented. Field data of three months trial running of the system and simulation data on OMNet++ platform have published good results of monitoring system with over 98% success ratio of data transmission, and WSN with energy balance in the every cluster and energy conservation of over one year lifetime.
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Computer Engineering. 2011, 37(23): 20-23. https://doi.org/10.3969/j.issn.1000-3428.2011.23.007Aiming at the problem that existing mandarin stress detection method has low accuracy rate, this paper proposes the complementary model method based on Boosting Classification and Regression Tree(CART) and Conditional Random Fields(CRFs). It is the combination of different classifiers to detect Mandarin character stress by using the acoustic, lexical and syntactic related features. In the ASCCD corpus, the complementary model achieves 84.9% stress detection correct rate, and there is 2.7% improvement when compared with the baseline system based on Neural Network(NN) and decision tree.
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Computer Engineering. 2011, 37(23): 24-26. https://doi.org/10.3969/j.issn.1000-3428.2011.23.008This paper presents an anomalous detection classifier of variance preserving named CP-ND. The covariance of normal examples is applied to preserve the statistical distribution of normal data and the margin between the decision hyper plane and abnormal points are maximized. The dual problem of this model can be solved as a quadratic programming. There are some inequalities among the three parameters of v, v1 and v2 introduced by this classifier, for normal class, vv1 indicates the rate of training misclassification and the rate of support vectors and vv2 indicates corresponding rates of abnormal class, those inequalities can be used to tune the three parameters. CP-ND classifier is evaluated on real-world medical diagnosis data sets.
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Computer Engineering. 2011, 37(23): 27-29,32. https://doi.org/10.3969/j.issn.1000-3428.2011.23.009This paper presents a memory-based frequent pattern incremental discovering algorithm for large-scale corpus. It extracts strings and counts frequencies of them from local area, prunes the local relative low frequency strings, and uses multi-mode string matching algorithm to count the local relative high frequency strings in the whole corpus, eventually gets the frequent patterns that the frequency is greater than the threshold. Experimental result shows that the algorithm has a better space complexity and the highest consumption of the memory size in the process of frequent-pattern discovery is about 20% to the size of the algorithm based on suffix array.
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Computer Engineering. 2011, 37(23): 30-32. https://doi.org/10.3969/j.issn.1000-3428.2011.23.010The Web service transactional workflow failure recovery algorithm always does not take the individual requirement of user and the chain failure recovery into consideration. This paper defines two failure recoveries grained the global transactional workflows model and executive transaction model, and proposes failure recovery algorithms based on the two grained. The transactional instance level hierarchical failure recovery is performed under fine-grained executive transaction model. The model-level recovery is performed under coarse-grained global transactional workflow to maintain the individual requirement of client. The algorithm determines the end compensation point dynamically and compensation costs are reduced, while in the process of recovery, the algorithm can search the compensation route under the global viewpoint and implement the chain failure recovery.
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Computer Engineering. 2011, 37(23): 33-36,39. https://doi.org/10.3969/j.issn.1000-3428.2011.23.011Aiming at the problem that current protecting technology has not provide the lifecycle security for the digital contents, this paper puts forward the Content Lifecycle Protection(CLP) concept and the corresponding protection model, which mainly employs ‘Box’ to wrap content into BCO so that box can supervise and protect inside content during each phase of lifecycle. By analyzing the elements in BCO, it presents BCO logical structure, physical structure and physical coupling structures respectively. The application experiment is implemented and key Web services based on PKC are described in detail, which proves the model’s reasonability.
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Computer Engineering. 2011, 37(23): 37-39. https://doi.org/10.3969/j.issn.1000-3428.2011.23.012This paper introduces the design and implementation of a literature metadata search and sharing system, based on meta-search and Web information extraction technology. The system provides users a unified retrieval interface to search and view the meta-data, which is collected from multiple sources and sorted in relevance. Furthermore, the system is a literature metadata sharing and discussion platform to facilitate the communication and collaboration between the researchers. Experimental results show that the system has better query performance, which can improve the efficiency of scientific research.
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Computer Engineering. 2011, 37(23): 40-42. https://doi.org/10.3969/j.issn.1000-3428.2011.23.013Scientific workflows oriented to solving processes of science problems are often data-centric. The verification of scientific workflows needs to take account of the rationality of both control-flow and data-flow. In this paper, four kinds of control relationships and two kinds of data relationships. After that, the rationality definition of scientific workflow is presented based on those relationships. Sequentially, relevant algorithms are proposed to obtain kinds of relationships among activities in scientific workflows and then the verification on scientific workflows could be realized according to those relationships. Several positive and negative examples are provided to illustrate the effect of this proposed approach.
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Computer Engineering. 2011, 37(23): 43-45. https://doi.org/10.3969/j.issn.1000-3428.2011.23.014This paper focuses on product features mining from reviews of Chinese network customers and proposes a method based on Apriori algorithm which is an unsupervised mining method. It extracts the candidate features collection by Apriori algorithm, and takes redundancy pruning and compactness pruning algorithms. According to the experimental research results, it establishes adjacent words value and p-support value. Results show that the precision and recall of mining method are effective improved by two proposed pruning algorithms.
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Computer Engineering. 2011, 37(23): 46-48,51. https://doi.org/10.3969/j.issn.1000-3428.2011.23.015According to PCI/CPCI bus computer’s real-time fault diagnosis problem, this paper proposes a way of building fault diagnosis based on the underlying software. The method relies on the virtual device driver as the underlying support, through the DriverWorks core layer class enuming device and initializing the device resource. It monitors the device working status by using status register. Combined with the middleware and application software, it completes the equipment fault diagnosis function. Experimental results show that the software is stable, has strong real-time, and diagnostic functions can be extended.
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Computer Engineering. 2011, 37(23): 49-51. https://doi.org/10.3969/j.issn.1000-3428.2011.23.016This paper proposes an efficient non-blocking coordinated checkpoint algorithm. In the algorithm, more processes can concurrently take consistent global checkpoints. The algorithm reduces the overhead by saving the state asynchronously and taking checkpoint when the amount of state information to be saved is small. The algorithm greatly lowers the overhead of checkpoint and improves system’s performance.
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Computer Engineering. 2011, 37(23): 52-53,59. https://doi.org/10.3969/j.issn.1000-3428.2011.23.017In order to solve the problem that components and data can not be automatically bond when generating user interface, a novel model of user interface is presented, which defines the data in the user interface and the relationship between data and component. Practical results show that using the model can achieve automatic binding of component and data, largely reduce the developing time, as well as improve the software development efficiency and maintainability.
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Computer Engineering. 2011, 37(23): 54-56. https://doi.org/10.3969/j.issn.1000-3428.2011.23.018To mine the rich semantic information in videos, this paper proposes a semantic concept detection method based on concept lattice rules reduced by negative samples. Through analyzing the semantic analysis system based on concept lattice and considering the information of negative samples in training data, it designs an algorithm for extracting semantic rules reduced by negative samples and apples the algorithm in video semantic detection. The low-level features of the video shots are mapped to the low-level semantic features, and the video semantic concept is detected after the semantic classification rules are generated by the proposed method. Experimental results show the feasibility and validity of the method.
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Computer Engineering. 2011, 37(23): 57-59. https://doi.org/10.3969/j.issn.1000-3428.2011.23.019Aiming at the problem of the existing coding algorithms can not meet the needs of high performance and large fault tolerance at the same time in RAID(Redundant Array of Inexpensive Disc) system, this paper proposes a algorithm for RS coding based on binary matrix. The method uses binary matrix to optimize the multiplication operation in finite fields. Meanwhile, the theory of multisection is used in the algorithm to reduce the XOR operation. Experimental result show that the proposed algorithm has high efficiency and good performance, and can be used in large fault-tolerant systems.
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Computer Engineering. 2011, 37(23): 60-62. https://doi.org/10.3969/j.issn.1000-3428.2011.23.020In order to verify the semantic correctness of workflow model, a method to check semantic properties of workflow model using π calculus is presented. A subset of π calculus, named πN calculus, is adopted to formally describe workflow model. The termination of reaction relation of structure sound workflow model is proved. An algorithm for constructing finite reaction transfer diagram is presented. Then the model checker NuSMV is used to check whether a workflow model satisfies some semantic properties expressed as the character of linear sequential logic. Experimental results prove that this method is effective.
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Computer Engineering. 2011, 37(23): 63-65,68. https://doi.org/10.3969/j.issn.1000-3428.2011.23.021Aiming at the problem that Windows can not be used in real-time fields directly because of its real-time faults, Windows real-time extension technology is studied. Common methods of Windows real-time extension are analyzed and compared, and the advantages and disadvantages of each method are summarized. Real Time eXpert(RTX) system and INtime, two typical products of Windows real-time extension, are compared from various angles, such as architecture, system basic mechanism, reliability, difficulty of developing real-time applications and system performance. They are bad at flexibility, reliability, and portability. A method of Windows real-time extension based on Adaptive Domain Environment for Operating System(ADEOS) is proposed.
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Computer Engineering. 2011, 37(23): 66-68. https://doi.org/10.3969/j.issn.1000-3428.2011.23.022Aiming at the term mismatch issues of existing information retrieval system, a novel query expansion algorithm of local feedback is proposed based on frequent itemsets and correlation. Those frequent itemsets containing original query terms and non-query terms synchronously are mined in the top-ranked n chapter retrieved local documents and non-query terms from the frequent itemsets are extracted to make into candidate expansion terms, and then the correlation of each candidate expansion terms and the entire original query is calculated. Final expansion terms are obtained according to its correlation for query expansion. At the same time, a new query expansion model and computing method for weights of expansion terms are presented. Experimental results show that the algorithm proposed is effective, can enhance and improve the performance of information retrieval.
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Computer Engineering. 2011, 37(23): 69-71,74. https://doi.org/10.3969/j.issn.1000-3428.2011.23.023The concepts of upper and lower approximation reduction of inconsistent lattice-value target information system are proposed and the judgment theorems are obtained. Moreover, the discernibility matrix and the detailed approaches are provided in order to get the upper and lower approximation reduction. An example demonstrates the validity of the approaches. The lattice-value target information system is the widest target information system. The reduction approach is valid for information systems in which all values of every attribute can compose a lattice.
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Computer Engineering. 2011, 37(23): 72-74. https://doi.org/10.3969/j.issn.1000-3428.2011.23.024To solve the problem of generate SQL code automatically in an intelligent study system, this paper proposes a method to transform natural language to SQL code. This paper builds a dictionary as the base of scanning and comprehension of natural language, uses the improved word collecting technique to distinguish the words and build a semantic dependency-tree, uses the set-block technology to separate the tree to several set blocks, and scans the set blocks and generate the SQL code. Experimental results show that this method simple and effective.
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Computer Engineering. 2011, 37(23): 75-76. https://doi.org/10.3969/j.issn.1000-3428.2011.23.025This paper presents a new method with Graphics Processing Unit(GPU) and CPU collaborate for matching the real-time marine data flow with the national standard data, and the result shows whether the water quality becomes abnormal. The method arranges and restores the marine data from distribute databases into a local stage of time series database, when system receives the requirement of matching, the GPU and CPU collaborate computing the marine data under the control of collaborate algorithm. The advantage of this method is both high-density computing and high bandwidth and the system can auto generate the matching result. Experimental results show that the method can effectively shorten the test time and improve detection efficiency.
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Computer Engineering. 2011, 37(23): 77-78,82. https://doi.org/10.3969/j.issn.1000-3428.2011.23.026This paper improves the AODV protocol used in the wireless Ad hoc network, realizes a new hybrid routing architecture by combining active and passive protocol, increases range limitation mechanism and compromise of distance and energy, the improved HR-AODV protocol has a better performance in Wireless Mesh Network(WMN), and it is more suitable for upper level applications in network layer. Simulation results using NS2 show that the HR-AODV protocol achieves a larger improvement in the network latency, packet loss rate, thought and so on, it has stronger robustness and fault tolerance.
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Computer Engineering. 2011, 37(23): 79-82. https://doi.org/10.3969/j.issn.1000-3428.2011.23.027In a disaster scenario, energy resources become scarce. It becomes one of the goals of routing scheme that minimize node energy consumption while forwarding packet efficiently. Routing scheme of opportunistic network based on grouping strategy is proposed. The nodes of network are grouped in accordance with the characteristics. The role of each group is different. Each group uses different routing strategy. The scheme is based on flooding strategy and can control the degree of flooding with p, k, t parameter. Simulation results show that in different network size, the scheme can be closed to the optimal network cost and achieve high delivery rate. It is a suitable routing scheme for disaster scenario.
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Computer Engineering. 2011, 37(23): 83-85. https://doi.org/10.3969/j.issn.1000-3428.2011.23.028To improve the performance of parallel network simulation, the topology of network simulation should be partitioned reasonably. On the basis of this, this paper proposes an optimized partitioning method of parallel network simulation topology. It analyzes key performance factors that affect the performance of parallel network simulation, gives a model for estimating the performance of parallel network simulation, the optimized partitioning of parallel network simulation is realized by treating this model as evaluating function, and the optimal partitioning by genetic algorithm is searched. Through experiments in PDNS, result shows that the performance of parallel simulation the optimized partitioning method improves by 13.3% in average compared with the traditional partitioning method.
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Computer Engineering. 2011, 37(23): 86-88,92. https://doi.org/10.3969/j.issn.1000-3428.2011.23.029Aiming at the problem of redundant coverage of the nodes in Wireless Sensor Network(WSN), an adjustable redundant covering algorithm is proposed based on K-coverage determination algorithm and partial redundancy covering algorithm. The algorithm follows the principle of maximizing coverage of the network while reducing energy consumption. After the efficient network is processed with the adjustable redundant covering algorithm, an energy-saving routing algorithm combined with the shortest path and the minimum spanning tree is posed. This algorithm constructs a number of shortest path trees to the Sink node for the root in the network, which reduce the energy consumption of network. Simulation results show that when the coverage redundancy is set for two, the two algorithms can reduce about 20.27% the energy consumption in the randomly deployed network.
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Computer Engineering. 2011, 37(23): 89-92. https://doi.org/10.3969/j.issn.1000-3428.2011.23.030To make up the defect that the real-time quality of traditional routing protocol is not high, this paper proposes a Power Aware Real-time routing algorithm based on Two-hop neighborhood information(THPAR). THPAR uses two-hop neighborhood information for routing decisions, and employs power-control mechanism to dynamically adjust nodes’ transmitting power in order to meet demand of different packet transmission velocity. As a result, it reduces the Deadline Miss Ratio(DMR), link packet loss ratio and increases robustness. Besides THPAR improves forwarding energy policy of THVR, it reduces the energy consumption. Simulation and comparison analysis between THPAR and THVR are done. Simulation results show that THPAR can perform better than THVR in term of energy consumption and delay.
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Computer Engineering. 2011, 37(23): 93-95. https://doi.org/10.3969/j.issn.1000-3428.2011.23.031Data persistence is the time interval of effectively disseminating and storing data among nodes to achieve the desire, how to improve the data persistence is a hot-spot in current research. In this paper, an improved scheme for improving data persistence named IIDP is proposed. In the scheme, nodes estimate the number of nodes in the network and the number of data packets by receiving packets for some time, then they can compute the parameter of restoring data and store the data. In order to achieve the store process as quick as possible, nodes adopt a probability-based forwarding scheme that they always transmit a packet to one of their neighbors who receives the packet the least of times. Theoretical analysis and experiments show that IIDP not only can achieve higher data persistence but also can be more energy efficiency than previous schemes.
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Computer Engineering. 2011, 37(23): 96-98. https://doi.org/10.3969/j.issn.1000-3428.2011.23.032Wireless Sensor Network(WSN) are not fit for the transmission of large-scale data because of their limited energy and bandwidth, and thus sensory data have to be compressed. This paper studies the problem of regression-based sensor network data compression. A linear regression algorithm based on segment and a regression adjustment algorithm based on confidence interval are proposed. Segment technique makes regression adapt to periodical change of environments whereas regression adjustment decides the time of segment, and thus regression line can approximate the environment data set more accurately. Through experiment of the Berkeley-Intel data set, result shows that the compression ratio of the proposed algorithms comes to 3% in minor reconfiguration precision.
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Computer Engineering. 2011, 37(23): 99-101. https://doi.org/10.3969/j.issn.1000-3428.2011.23.033Aiming at the disadvantage of traffic-adaptive Media Access Control(MAC) Protocol, this paper gives an improved scheme of dynamic duty cycle mechanism. Based on S-MAC and TDMA traffic-adaptive MAC protocol, it introduces the dynamic duty cycle mechanism, the original listening/sleep cycle of S-MAC protocol is divided into several short listening/sleep cycles to transmit data repeatedly. NS2 simulation results show that the improved protocol can effectively lower system delay and power consumption, maintain higher throughput and achieve smooth switch of protocols.
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Computer Engineering. 2011, 37(23): 102-104. https://doi.org/10.3969/j.issn.1000-3428.2011.23.034Existing Wireless Sensor Network(WSN) topology control algorithms are mostly based on ideal wireless environment, and it need node position information. This paper proposes a topology control algorithm based on path loss. It constructs topology through computing path loss of forward and backward paths with three or fewer hops from one node to another. Simulation result shows that this algorithm can reduce network energy consumption and the communication interference between the nodes, maintain the network connectivity, prolong the network life cycle.
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Computer Engineering. 2011, 37(23): 105-106,109. https://doi.org/10.3969/j.issn.1000-3428.2011.23.035The World Wide Web(WWW) constitutes a massive complex network that is far beyond for a traditional random network model to describe its structure and behaviors. By analyzing the network link data, the relevant parameters and factors are established and computed by comparing theory with practice implication. It concludes that the WWW has the small world effect, the average shortest path of the WWW is about 15 hops, clusters are groupings of Web pages devoted to the same topic and then form scale-free networks.
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Computer Engineering. 2011, 37(23): 107-109. https://doi.org/10.3969/j.issn.1000-3428.2011.23.036Aiming at the search shortcoming and the low efficiency of Object Naming Service(ONS) for the Internet of things, this paper proposes an information query system, which is based on Distributed Hash Table(DHT) networking search technology——Chord algorithm. Simulation experiments by OMNET++ network simulation platform prove that the network load balance and inquiry efficiency are improved. It makes the network delay reduced from 1.5 s to 0.025 s, which is suitable for the Internet of things.
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Computer Engineering. 2011, 37(23): 110-112. https://doi.org/10.3969/j.issn.1000-3428.2011.23.037The main problem of the original Enhanced Distribution Channel Access(EDCA) is that the values of the main parameters of each Access Category(AC) queue are static and do not take into account wireless channel conditions. In this paper, every station in the network tuned Contention Window(CW) dynamically, according to the current network load adopting the slot utilization to evaluate, and adjusts minimum CW and maximum contention window by the collision rate in per AC queue, thus improves the performance of the network. Simulation results show that this algorithm can ensure the requirement of the real-time traffic, reduce effectively the delay and increase significantly the throughput of wireless LAN.
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Computer Engineering. 2011, 37(23): 113-115. https://doi.org/10.3969/j.issn.1000-3428.2011.23.038Based on distance vector routing algorithm, this paper improves the update strategy of SpaceWire router, and proposes the Link-State (L-S) route selection algorithm. By analyzing the executive process of L-S route selection algorithm and the principle of Dijkstra algorithm, it completes the design of routing module, and simulates the module by use of a simple network model. Verification result demonstrates that this module can get the information and recalculate new route information of current network automatically, improve the ability of self-adaptive of SpaceWire network and intensify the transmit efficiency as well.
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Computer Engineering. 2011, 37(23): 116-118. https://doi.org/10.3969/j.issn.1000-3428.2011.23.039This paper proposes and evaluates a new time synchronization protocol called Hierarchical Time Synchronization Protocol(HTSP) which is an advanced version of the Flooding Time Synchronization Protocol(FTSP). The concept of hierarchy is adopted, and the hierarchy concept is used in collecting statistics for the number of child nodes of each node. With the collected number of child nodes, the HTSP can reduce the number of packet transmission. Simulation results show the energy consumption of the HTSP is only 74% of that of the FTSP.
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Computer Engineering. 2011, 37(23): 119-120,128. https://doi.org/10.3969/j.issn.1000-3428.2011.23.040This paper applies the theory of sparse representation to learn robust features. By fusing class information into the training process, it applies discriminant K-SVD algorithm to intrusion detection, which optimizes the over-completed dictionary and the linear discriminant function together. When testing, it uses the sparse coefficients as sample’s feature, which is more effective representational and discriminative power. Experimental results demonstrate that it can guarantee higher detection rate and lower false alarm rate. Meanwhile, it has good robustness in the imbalanced dataset experiment.
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Computer Engineering. 2011, 37(23): 121-123,124. https://doi.org/10.3969/j.issn.1000-3428.2011.23.041Node replication attacks can directly damage the sensor nodes, and has strong destruction to seriously impact on the Wireless Sensor Network(WSN). Against such attacks, this paper presents an improved detection method of node replication attack. The network is organized into the cluster based on the LEACH algorithm, and the level of trust is determined regularly by threshold computation, the node chooses to receive or reject the data by its level of trust. The node within the cluster can effectively detect the node replication attack based on the witness node. Simulation results show that this approach can improve the detection efficiency of node replication, and compared with the traditional methods, the energy and transport costs low.
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Computer Engineering. 2011, 37(23): 124-126. https://doi.org/10.3969/j.issn.1000-3428.2011.23.042To solve the problem of efficiency and veracity of intrusion detection, this paper presents an intrusion detection model based on quantum genetic algorithm and neural network. The model takes advantage of the global search property of the quantum genetic algorithm and the exact local search characteristics of the BP neural network, and combines quantum genetic algorithm and BP neural network. The weight and the thresholds of the BP neural network are optimized by the improved quantum genetic algorithm, so that the BP neural network enhances efficiency and veracity of intrusion detection, thereby improving network security. Matlab emulating experiments of this model show this method is better than other kinds of methods in detection rate and false alarm rate.
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Computer Engineering. 2011, 37(23): 127-128. https://doi.org/10.3969/j.issn.1000-3428.2011.23.043In view of the questions that the proposed partially blind signatures very little consider the randomization property, and also very little give any formal proofs. A provably secure randomized partially blind signature scheme based on bilinear pairing is presented. In the scheme, a method is used that the randomization parameter is decided by the random numbers chose by the signer and the signature receiver, and some formal proofs from correctness, randomization, unlinkabiliy and unforgeability of the scheme are given, which makes the scheme more security.
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Computer Engineering. 2011, 37(23): 129-131. https://doi.org/10.3969/j.issn.1000-3428.2011.23.044On the basis of Role-based Access Control(RBAC), this paper adds user’s static trust level and dynamic trust level, presents a kind of user trust based dynamic multi-level access control model. The model can get static permission according to user static trust value and role, and can judge the user behavior trust and decide the concrete application permissions according to user dynamic trust value in the process of user accessing resource. It gives the application example and the safety analysis, results show that the model can grant authorization dynamically and meets minor privilege principle.
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Computer Engineering. 2011, 37(23): 132-134. https://doi.org/10.3969/j.issn.1000-3428.2011.23.045Piecewise linear recognition algorithm is introduced in this paper, and an linear approximaiton Support Vector Machine(SVM) model for intrusion detection is proposed. In this model, the feature space is partitioned into several sub-space, the five best face are made in each sub-sector based on support vector classification, and then link together to form each of five categories face the optimal classification surface patch to approximate the theoretical optimal separating hyper surface. Experimental results show that the model needs short training time, and in the presence of noise data, it has high detection accuracy rate.
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Computer Engineering. 2011, 37(23): 135-137,140. https://doi.org/10.3969/j.issn.1000-3428.2011.23.046This paper proposes a new video steganography algorithm based on the differences of motion vector components for H.264/AVC video compression standard. In view of the characteristics of Human Visual System(HVS), the algorithm filters the motion vectors which HVS is less sensitive to. It uses the difference between the chosen motion vectors components to control the operating position, and embeds secret message in the component. During embedding, only to modify the component with larger absolute value, and the operation is symmetric, so that the impact of the carrier’s statistical properties is reduced. Theoretical analysis and experimental results show that the algorithm obtains the higher carrier utilization and embedding efficiency, and achieves the requirements of covert communication about the invisibility and capacity.
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Computer Engineering. 2011, 37(23): 138-140. https://doi.org/10.3969/j.issn.1000-3428.2011.23.047The existing technologies of logging file protection are mainly focusing on protecting logging files from attack outside, but the logging files are exposed in a hostile environment and malicious users who is legitimate may tamper or delete the logging files. This paper proposes a client logging protection mechanism in hostile environment. It encrypts and signs the logging file based on USB Key. It protects the logging files’ generation, storing and uploading. Security and performance analysis proves the validity and security of this mechanism.
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Computer Engineering. 2011, 37(23): 141-143,146. https://doi.org/10.3969/j.issn.1000-3428.2011.23.048In order to solve the unnecessary root users in the operating system services, a user permission isolation model is proposed. Based on the mapping link among users, isolated domains and program modules according to the security level, associated with the use of virtualization, isolated runtime environments are constructed for different users. The model gives formal definition of user isolated domain and the key mechanisms for its implementation. The model realizes least privilege principle for the isolated domain, and the paper gives the conclusion that potential root users are eliminated in the isolated domains.
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Computer Engineering. 2011, 37(23): 144-146. https://doi.org/10.3969/j.issn.1000-3428.2011.23.049This paper studies the certificate protection mechanism in Windows operating system, it analyses the theory of the three security measures which include the private key export flag protection, the private key accession prompt protection and the password protection. A research method that uses a combination of forward analysis and reverse engineering is applied. It shows that there are security risks in the certificates in the form of software in the Windows operating system. It proposes that it can improve the certificates’ security by storing in the hardware.
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Computer Engineering. 2011, 37(23): 147-148,151. https://doi.org/10.3969/j.issn.1000-3428.2011.23.050In fuzzy vault scheme, a set with genuine points of a user mixed with a lot of chaff points represents a vault. However, there are some secure flaws in this scheme. To solve these problems, a novel scheme is presented to construct a vault, in which a random polynomial instead of a set is used to represent the vault. Theoretical analysis results show that the new scheme can defeat the existed attacks. It needs less memory than that in the original scheme.
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Computer Engineering. 2011, 37(23): 149-151. https://doi.org/10.3969/j.issn.1000-3428.2011.23.051Substitution(S)-box designed by traditional method is not very good, and some intelligent algorithm methods are easy to fall into local optimum shortcomings and waste too much time. In this paper, particle swarm algorithm using dynamic inertia weight is used to design S-box. Searching speed and precision are improved by inertia weight. Experimental results show that the method can search a lot of S-box which is useful resistance to differential cryptanalysis and linear cryptanalysis.
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Computer Engineering. 2011, 37(23): 152-154. https://doi.org/10.3969/j.issn.1000-3428.2011.23.052Aiming at security verification problem of trusted application environment, this paper uses Communicating Sequential Processes(CSP) to describe non-interference performance of the system. Based on mandatory access control mechanism, it tags all software packages in the system, and models system application processes. The model is input into FDR2 to do experiment, whose result shows that the application execution process is secure and trusted, which can resist unexpected interference from other applications.
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Computer Engineering. 2011, 37(23): 155-158. https://doi.org/10.3969/j.issn.1000-3428.2011.23.053In order to solve information security problems caused by the crack of triple encryption algorithm of Mifare 1(M1) card, this paper proposes some security mechanisms and policies. It need not send plaintext between communicating parties but ciphertext. By using fast and secure Advanced Encryption Standard(AES) algorithm and combing fixed key and random key, the security of encrypted data is improved. Experiments on embedded Linux systems show that M1 card system is stable, secure and efficient.
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Computer Engineering. 2011, 37(23): 159-161,164. https://doi.org/10.3969/j.issn.1000-3428.2011.23.054Virtual teacher usually express their emotions through facial expression. The mapping mechanism between high-level psychological parameters such as emotion and personality and low-level animation parameters of face model and human model is proposed. The behavioral model of emotional expression based on body language is established. The atomic actions library is built based on body parts of expressing emotions. The method of generating emotional expression strategies is designed based on Bayesian networks. The realistic and rich expression with body language is implemented through script technology. Experiments on OpenSim prove that the behavioral model of emotional expression is practical.
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Computer Engineering. 2011, 37(23): 162-164. https://doi.org/10.3969/j.issn.1000-3428.2011.23.055Gaussian Mixture Model(GMM)——universal background model is used for most of text-independent speaker validation systems in the past decade. This paper proposes a new structure of GMM——Sorted Gaussian Mixture Model, in which each Gaussian components in the universal background model are arranged in corresponding value order, it is an approach to combine with the clustering method to train UBM. Experiments on the 2006 NIST 8side-1side subset speaker recognition evaluation task show that after using this approach, the amount of calculation can be reduced, and under certain search width conditions, almost no reduction in recognition performance.
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Computer Engineering. 2011, 37(23): 165-167. https://doi.org/10.3969/j.issn.1000-3428.2011.23.056The discriminant model learned by traditional ranking algorithm based on Pairwise method is not accurate. Aiming at the above problem, a novel ranking algorithm based on Listwise method is proposed. The algorithm uses the discriminative model and adopts one-slack Support Vector Machine(SVM) as its framework. On this basis, the algorithm defines its objective function. In order to solve the problem of exponential size of constraints in the optimization, a cutting plane algorithm is introduced. For the sub-problem of finding the most violated constraints, the paper presents to view it as a linear assignment problem, and adopts Hungarian method to solve it. Experimental results on the benchmark datasets prove the effectiveness and stability of the algorithm.
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Computer Engineering. 2011, 37(23): 168-170. https://doi.org/10.3969/j.issn.1000-3428.2011.23.057This paper presents a walking gait cycle recognition based on Peak-valley Piecewise Integrator(PVPI) algorithm, it uses Surface Electromyogram Signal(SEMS) as information source. The SEMS signal can be real-time sampled by SPCE061A MCU, and communicate with PC through RS232. The digital value of signal can be delivered to the PC. The gait cycle identification experiment system is designed through Visual C++6.0 based on PVPI algorithm. The signals analysis are sampled from 8 SEMS of 6 bodies when walking. The results of the system show that the walking gait cycle identification method is accuracy and reliablity.
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Computer Engineering. 2011, 37(23): 171-173. https://doi.org/10.3969/j.issn.1000-3428.2011.23.058To improve the convergence speed and accuracy of the basic Bacterial Foraging Algorithm(BFA) according to the high dimensional problems, this paper proposes a BFA based on Particle Swarm Optimization(PSO) and Opposition-based Learning(OBL), namely PO-BFA. It employs OBL for population initialization and for generation jumping, while uses the fly of particles same as PSO instead of bacteria chemotaxis, and omits the swim of the bacteria. Simulation results on six benchmark functions show that PO-BFA is superior to other kinds of BFA.
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Computer Engineering. 2011, 37(23): 174-176,180. https://doi.org/10.3969/j.issn.1000-3428.2011.23.059According to the traffic flow features of urban expressway, the maximum total flow and minimum average waiting time at ramp are considered as the optimization goal based on Macro-state model. Meanwhile, a joint control model is designed using multiple ramps metering. Futhermore, the Ant Colony Optimization(ACO) algorithm is used for calculating the optimal adjust rates of ramps. Simulation results show that it can improve the operational efficiency of the expressway system and reduce the probability of traffic accidents and traffic jams.
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Computer Engineering. 2011, 37(23): 177-180. https://doi.org/10.3969/j.issn.1000-3428.2011.23.060Word segmentation systems do not include compound words into their dictionaries, so they can not recognize compound words. To address this problem, this paper proposes a Chinese compound word extraction algorithm based on word co-occurrence graph. It gets word strings from a document through by part-of-speech detecting, generates word co-occurrence directed graph,, and borrows the idea of the Bellman-Ford algorithm to search the longest paths with weight values satisfy the given conditions for multiple starting points in the word co-occurrence directed graph. The word strings corresponding to the paths are considered as compound words. Experimental results show that the algorithm achieves 91.16% upon the precision.
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Computer Engineering. 2011, 37(23): 181-182,185. https://doi.org/10.3969/j.issn.1000-3428.2011.23.061Because of background noisy, there is a problem of directly separating the mixed-signal observed usually can not achieve good results. The basic principle and algorithms of independent component analysis is illustrated. Considering characteristic of Kalman filtering, the speeches under background noisy are denoisied; and speeches are separated by the FastICA algorithms. Simulation results indicate the availability and efficiency of this method.
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Computer Engineering. 2011, 37(23): 183-185. https://doi.org/10.3969/j.issn.1000-3428.2011.23.062A new cultural algorithm with double populations is proposed for designing Finite Impulse Response(FIR) digital filters. Two populations evolve independently according to Particle Swarm Optimization(PSO) algorithm and Differential Evolution(DE) algorithm respectively. Belief space plays the role of knowledge link in mutual cooperation and promotion between populations. This algorithm provides a new way for the co-evolution technique of multi-population. The computer simulations of FIR filter design indicate that the proposed algorithm is practicable and superior in terms of convergence speed and optimization effect compared with other algorithms.
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Computer Engineering. 2011, 37(23): 186-188,207. https://doi.org/10.3969/j.issn.1000-3428.2011.23.063This paper presents a video smoke detection algorithm based on Adaptive Neuro-fuzzy Inference System(ANFIS). The smoke features are extracted from video sequences, and the subtractive clustering is introduced to confirm the fuzzy rule number. The premise parameters and the consequent parameters are updated by hybrid learning rule. The fuzzy inference rules are obtained. Experimental results show that compared with the traditional BP neural network algorithm and Support Vector Machine(SVM) algorithm, the new algorithm has better performance on Receiver Operating Characteristic(ROC) curve.
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Computer Engineering. 2011, 37(23): 189-191,202. https://doi.org/10.3969/j.issn.1000-3428.2011.23.064A method of Infrared image segmentation based on Multiscale Auto Regressive Analysis(MARA) and Two-dimensional TSV(TDTSV) entropy is proposed. MAR model is used to establish mathematic relationship among different image layers, and is combined with the method of two-dimensional TSV. Through the optimization of the regression coefficient, the adjacent scale image is combined reasonable, then it leads to a more accurate segmentation. Experimental results on infrared image show that this method reduces the iterative times of segmentation and inaccuracy classify blocks, and gets clear and smooth object border.
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Computer Engineering. 2011, 37(23): 192-194. https://doi.org/10.3969/j.issn.1000-3428.2011.23.065This paper proposes a Super-resolution(SR) algorithm with adaptive regularization based on weight. In case of existence of local motion and/or occlusion, regions that have local motion and/or occlusion have different noise level. To cope with this problem, it proposes to adaptively weight each region according to its reliability and the regularization parameter is simultaneously estimated for each region. The regions are generated by segmenting the reference frame using watershed segmentation. Experimental results show the effectiveness of the algorithm.
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Computer Engineering. 2011, 37(23): 195-196,199. https://doi.org/10.3969/j.issn.1000-3428.2011.23.066Existing exemplar-based concealment algorithms have high computational complexity. In order to solve the problem, a real-time spatial error concealment algorithm using segmentation is proposed. The error block is first segmented by its texture characteristic, and each segmented sub-block is recovered by searching the best matching block in texture region. The paper uses this method to realize the concealment. Experimental results show that, the proposed algorithm can provide better image concealment quality while decreasing the computational complexity compared with other classic exemplar-based error concealment algorithm.
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Computer Engineering. 2011, 37(23): 197-199. https://doi.org/10.3969/j.issn.1000-3428.2011.23.0067The blocking artifact is noticeable in the block partitioning Bidimensional Empirical Mode Decomposition(BEMD) based radial basis function interpolation. For alleviating the blocking artifact problem, it proposes a modified blocking BEMD method. This paper calculates the enlargement size of each image block by the minimal symmetry resemblance variance of adjacent blocks, and the decomposing results of each block are fused by an adaptive seamless splicing method. Experimental results show that, this algorithm can improve the phenomenon of montage distortion.
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Computer Engineering. 2011, 37(23): 200-202. https://doi.org/10.3969/j.issn.1000-3428.2011.23.068A new auto-exposure algorithm is proposed to solve the different requirements of exposure parameter, which is because of the different flame types and the flame itself flaring in the gathering process of the lighter flame image. Preliminary this paper calculates the exposure parameter based on the brightness of the flame, then combines the relationship between exposure time and gray of the image with dichotomy for determining the scope of the exposure time. Experimental results show that the exposure time of this algorithm can be controlled correctly, fleetly and automatically according to the different lighter flame. The precision of the auto-exposure is more than 97.2%.
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Computer Engineering. 2011, 37(23): 203-204,210. https://doi.org/10.3969/j.issn.1000-3428.2011.23.069It is required to preserve the relativity information of each channel for color image when it is compressed. This paper proposes a compression method based on a new style of Singular Value Decomposition(SVD) founded on Young-Helmholtz model——YH-SVD. It proofs the existence and gives out the structural style of YH-SVD, and applies this method to compress color image after it is transformed into Greaves space. Experimental results show that this method can keep the clearness of reconstructed image, and can achieve high Peak Signal to Noise Ratio(PSNR).
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Computer Engineering. 2011, 37(23): 205-207. https://doi.org/10.3969/j.issn.1000-3428.2011.23.070Traditional pairwise sequences alignment algorithms are mostly based on dynamic programming, there are some problems when using dynamic programming to align for its slow speed and low accuracy. Pairwise sequences search and alignment algorithm based on Boolean logic is proposed in this paper. The algorithm searches homologous regions in the pairwise sequence using a fixed-length base fragment in one sequence, and performs the alignment between the homologous regions at once, including the alignment of the bases in the homologous regions and the alignment between the subsequence and the other sequence. It also makes use of concurrent execution mechanism to realize the parallel speed up. Simulation experimental results show that the algorithm has higer real-time and accuracy.
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Computer Engineering. 2011, 37(23): 208-210. https://doi.org/10.3969/j.issn.1000-3428.2011.23.071A Matlab function model is built through using CORDIC algorithm and butterfly operation without multiplier. By choosing reasonable iterative series and the operation data bit width, a novel Fast Fourier Transform(FFT) processor with high Signal Noise Ratio(SNR) is designed. In the Matlab simulation, the SNR can reach 88 dB. After adding the overflow protection, the SNR realized by hardware can reach 80 dB, and the power consumption can be reduced by 20.63%. The designed FFT processor has many advantages such as smaller chip area, high accuracy, lower power consumption and high SNR.
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Computer Engineering. 2011, 37(23): 211-213,225. https://doi.org/10.3969/j.issn.1000-3428.2011.23.072Currently, a great amount of time is spent on tuning recipe when facing complicated 2D patterns. This paper provides a lithography model segmentation optimization method based on a ripple wave suppression algorithm, which allocates fragments according to extrema on aerial intensity curve and then optimizes algorithm parameters by grid point searching to obtain optimal segmentation scheme. Experimental results show that, this method not only provides stable recipe tuning time, but obtains better Optical Proximity Correction(OPC) fidelity with average reduction of 5% in Edge Placement Error(EPE) comparing with the results from a reference recipe.
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Computer Engineering. 2011, 37(23): 214-216. https://doi.org/10.3969/j.issn.1000-3428.2011.23.073This paper presents a floating-point Sparse Matrix Vector Multiply(SMVM) on reconfigurable computing platform, because traditional implementation SpMXV on General Purpose Processor(GPP)is very inefficient. The design of SpMXV co-processor is based on IEEE-754 32 bit floating point data formats, diagonal storage scheme and the binary tree data flow. The implementation on reconfigurable computing platform is pipeline and highly efficient parallel. Simulation results illustrate that SpMXV on a reconfigurable computing platform can speedup over the software version of the same algorithm about 2.69 times.
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Computer Engineering. 2011, 37(23): 217-219. https://doi.org/10.3969/j.issn.1000-3428.2011.23.074For the unsuitable Field Programmable Gate Array(FPGA) implementation of the Pairwise Coupling probability modeling and the poor classification performance of the voting probability modeling which are the two commonly used Support Vector Machine(SVM) probability modeling algorithms based on One Against One(OAO) classification strategy, an optimized algorithm for hardware implementation of probability modeling SVM is proposed which is based on Sigmoid function and Log-add with combined computation is proposed from the point of compromise. The theoretical analysis shows that this algorithm avoids complex iterative calculation and a large number of exponential calculations. It greatly reduces the amount of computation and is easy for FPGA implementation.
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Computer Engineering. 2011, 37(23): 220-222,235. https://doi.org/10.3969/j.issn.1000-3428.2011.23.075In terms of the control strategy of Permanent Magnet Synchronous Motor(PMSM), a double closed-loop control system for electricity and speed which is based on Space Vector Pulse Width Modulation(SVPWM) is established. With the help of Altera DSP Builder, digital control system on the basis of FPGA is accomplished by providing the design method of sectors deciding, vector time, calculation of turn-on time, distribution of turn-on time, 6-channel PWM signal generation, Park transform and inverse transform, Clarke transform, and PI control method. Simulation results testify that the system has the advantages of static and dynamic characteristics. It also provides an effective method for SoC design of PMSM control system.
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Computer Engineering. 2011, 37(23): 223-225. https://doi.org/10.3969/j.issn.1000-3428.2011.23.076For solving the low efficiency of Network on Chip(NoC) verification, this paper constructs the coverage-driven constrained random and hierarchical NoC testbench based on the Verification Methodology Manual(VMM) and application of SystemVerilog. Results of NoC performance evaluation with heterogeneous topologies or traffic distributions show that the testbench is superior in generality, has good adaptability, scalability , and can effectively improves the verification efficiency.
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Computer Engineering. 2011, 37(23): 226-228,231. https://doi.org/10.3969/j.issn.1000-3428.2011.23.077A new approach of Reconstruction-based Contribution(RBC) is proposed to solve the problems that traditional diagnosis method based on Dissolved Gas Analysis(DGA) is not sensitive to fault data. The SPE and T2 indices are used to fault detection after Principal Component Analysis(PCA) model is built up, the diagnosability of RBC method is analyzed and it is applied to the fault diagnosis. Case studies show that the proposed method is able to identify the reason of a fault effectively and enhance fault diagnosis accuracy, it has very good fault distinguishing ability and vast prospect.
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Computer Engineering. 2011, 37(23): 229-231. https://doi.org/10.3969/j.issn.1000-3428.2011.23.078As the FlexRay network technology in the vehicle field is seldom used, this paper focuses on the implementation of FlexRay vehicle networking, and builds an applications prototype system with the FlexRay vehicle network. It also gives a reasonable test and evaluation on the network performance. Experimental results show that the FlexRay network has a unique advantage on transmission speed, security, and real-time. It can easily improve vehicle handling, safety and comfort, and is consistent with the development of next-generation vehicle network needs.
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Computer Engineering. 2011, 37(23): 232-235. https://doi.org/10.3969/j.issn.1000-3428.2011.23.079In the distributed mass storage test, some test nodes may be the situation of depletion of resources even crash, which seriously affects the results of accuracy and credibility. Meanwhile, since there are a large number of database operations on the test platform, MySQL database’s performance nust be assessed exactly. To solve the above problems, this paper designs and implements a distributed monitoring management system, it can real-time monitor test nodes and MySQL's performance, provide alarm system as well. The distributed monitoring management system is tested, result shows that the system can reasonably adjust test tasks, allocate system resources and improve overall system’s performance.
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Computer Engineering. 2011, 37(23): 236-237,240. https://doi.org/10.3969/j.issn.1000-3428.2011.23.080A management of vehicle information in new train monitoring device is designed and implemented in the paper. Using double redundant Controller Area Network(CAN) communication network, the management realizes the function, which can on-line synchronous update and manage the train log data, with the online programmable NOR FLASH and mobile massive storage device. Various tests prove that the new vehicle information management employed greatly improves the reliability of train monitoring device, update efficiency and security of the train information.
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Computer Engineering. 2011, 37(23): 238-240. https://doi.org/10.3969/j.issn.1000-3428.2011.23.081In order to solve the difficult problems about heterogeneous system integration and data exchange, the paper designs Evaluation and Four-queue Schedule Model(EFSM) task schedule model based on integrated platform of SOA(Service Oriented Architecture). In the platform, it uses XML format editing data exchange message, analyzes of 3 kinds of data exchange in the SOA integrated platform, and gives task queue schedule algorithm of grid computing based on the scheduling ideas, according to Min-Min algorithm for schedule tasks, with the bottleneck of forwarding task improvement. Experimental results show that, the model can efficiently operate in the SOA integration platform.
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Computer Engineering. 2011, 37(23): 241-243. https://doi.org/10.3969/j.issn.1000-3428.2011.23.082This paper presents an algorithm for solving Minimum Spanning Tree(MST) problem based on the node combination and reverse direction tracing method. According to the adjacent matrix, the source node and the adjacent nodes are combined into new source node repeatedly and all the nodes in the network are combined into one single node. By introducing the front point label array, it gets the MST. The correctness and complexity of the algorithm are analyzed. It applies the algorithm to the highway system engineering construction plan, the results prove the validity of the algorithm.
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Computer Engineering. 2011, 37(23): 244-247. https://doi.org/10.3969/j.issn.1000-3428.2011.23.083In view of the problems about unsatisfactory integration analysis, pool interactive and so on in the information system of Three Gorges reservoir. This paper constructs a hydro-environment analysis system of Three Gorges reservoir after studying the pattern of RIA and Flex technology and using Flex framework, database, Web Geographic Information System(GIS) and .Net technology. It designs the architecture and describes middleware and so on crucial technology, implements the system. Result shows that Flex technology has more efficient interactive capability and richer forms of representation, satisfies the demand for integration analysis, provides a good support for protecting the hydro-environment.
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Computer Engineering. 2011, 37(23): 248-250. https://doi.org/10.3969/j.issn.1000-3428.2011.23.084This paper presents a research on key problem of superdistribution, especially for service provider being critical part of business operation in digital reading. It proposes an update package method to solve multi-device compatibility problem for supporting service provider’s value-added service. A value-added license is designed to describe new permission added by service provider. On online reading service aspect, flow segmentation technology is designed to redesign layout. And virtual file technology is designed to support value-added service in local rights and service management. Experimental results show that the method is feasible and valid.
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Computer Engineering. 2011, 37(23): 251-253. https://doi.org/10.3969/j.issn.1000-3428.2011.23.085The vehicle power system has the fewer test points and the testing data are incomplete. Aiming at these characteristics, it proposes that combining multi-signal flow graph model with Bayesian network fault diagnosis method. The fault diagnosis model of power system is built by applying multi-signal flow graph. The dependence matrix which relates faults and testing signals is generated based on the model, and setting up the corresponding Bayesian network structure for the fault diagnosis, based on historical data to complete the network parameter learning. Using the maximum posterior probability of failure as a criterion to achieve the fault diagnosis of power system. Simulation results verify the effectiveness of the method.
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Computer Engineering. 2011, 37(23): 254-256. https://doi.org/10.3969/j.issn.1000-3428.2011.23.086It is difficult for the reproducing, the rapid transmission based on network and the real time visualization of calculated results of finite element models that there is a large amount of data in finite element post-processing stage in groundwater. Therefore, based on analyzing the main problems existing in the post-processing of finite element in groundwater and Level of Detail(LOD) technology, this paper argues that vertex element deletion method is a effective data model simplification techniques adapted for finite element post-processing in groundwater, the main data structures of vertex element deletion and restoring are designed, DT method is used for the local triangulation meshing in the “hole” area. The real implemented example proves the effectiveness of vertex element deletion algorithm applied to finite element post-processing in groundwater.
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Computer Engineering. 2011, 37(23): 257-260. https://doi.org/10.3969/j.issn.1000-3428.2011.23.087In order to automatically remove the ocular artifact from Electroencephalogram(EEG) data, this paper presents an effective and robust algorithm. Blind Source Separation(BSS) algorithm is used to separate real EEG signal, and a universal approach together with sample entropy is employed to identify the artifact components. The artifact is eliminated through reconstruction of EEG data. Simulation results are compared with a robust method based on fractal dimension and show the proposed algorithm can eliminate ocular artifact accurately and do little harm to useful EEG signals that for real EEG data of different lengths. Meanwhile, the proposed method does not need any reference channel, and is fully automated, which is suitable for real-time applications.
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Computer Engineering. 2011, 37(23): 261-263. https://doi.org/10.3969/j.issn.1000-3428.2011.23.088Aiming at the current situation of the demand of medical electronic endoscope to image quality is more higher, a solution of embedded endoscope high definition video processing system based on Field Programmable Gate Array(FPGA)+dual Digital Signal Processor(DSP)s is proposed. FPGA is applied to preprocess the video image, and dual DSPs based on DaVinci technology are applied parallel to H.264 encoding/decoding, then PowerPC processor is applied to the system management, hard disk storage and network transmission. Test results show that, the resolution of the system is 1080i60, and the support of H.264 High-Profile has good performance.
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Computer Engineering. 2011, 37(23): 264-266. https://doi.org/10.3969/j.issn.1000-3428.2011.23.089An algorithm of LT coding and decoding based on One-dimensional Markov Mapping(ODMM) is presented to solve the problem of transmission and recovering of degree and adjacency relationship in block coding of fountain codes. According to the distribution of ODMM in phase space, the degree and adjacency data in block coding are selected through uniform distributed pseudorandom sequence which is generated by the mapping equation. Using the initial value of chaotic equation as public keys, the low overhead transmission and recovering of degree and adjacency relationship of fountain codes are implemented. Results of simulation show that the algorithm is easy to realize, reduces the losses in transmission and increases the success rate of decoding.
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Computer Engineering. 2011, 37(23): 267-269. https://doi.org/10.3969/j.issn.1000-3428.2011.23.090In order to efficiently plan the collection routes of medical waste from a disperse group of facilities, a two-phased heuristic algorithm is investigated. In this heuristic algorithm, the first phase solves a standard vehicle routing problem to determine a set of individual routes for the collection vehicles, the second phase uses a mixed integer programming method to assign routes to particular days of the week. An illustrative example for the medical waste of 328 hospitals in the Kunming city area demonstrates the effectiveness of the system.
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Computer Engineering. 2011, 37(23): 270-272. https://doi.org/10.3969/j.issn.1000-3428.2011.23.091Return Oriented Programming(ROP) techniques can be used to bypass Data Execution Protection(DEP), but it is complicated and time-consuming to analyze the available code sequences in the executable library to combine them into ROP gadgets manually. This paper uses gadgets dictionary to build ROP gadgets automatically on Windows, which can perform arbitrary computation and is Turing-complete. Using ROP Gadgets generated automatically, exploit developer may accelerate the process of developing Exploit bypassing DEP.
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Computer Engineering. 2011, 37(23): 273-275. https://doi.org/10.3969/j.issn.1000-3428.2011.23.092For the aircraft Environmental Control System(ECS) optimization analysis, entropy generation analysis method based on the second law of thermodynamics is proposed. The flight phase of take-off, climb and supersonic penetration is chosen be design point, system entropy generation minimum is chosen be objective function, the optimization model is established through choose efficiency of primary and second heat exchanger, pressure ratio of compressor and turbine, flow ratio of heat exchanger, mass flow of bleed air be design variables. The relationship between system entropy generation and design variables is analyzed based on optimization calculation results. Analysis results have some instruct function on aircraft environmental control system optimization design.
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Computer Engineering. 2011, 37(23): 276-278. https://doi.org/10.3969/j.issn.1000-3428.2011.23.093Existed main text localization methods in webpage information extraction technologies only consider the text information. Those methods lead to low accuracy when main text contains a few text information and abundant image information. In order to solve this problem, this paper designs a method to estimate the image information and image effective information based on information theory, and presents a novel algorithm for main text of webpage localization based on image and text effective information. Experimental results show that on different main text ratio, this algorithm has higher accuracy.
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Computer Engineering. 2011, 37(23): 279-281,287. https://doi.org/10.3969/j.issn.1000-3428.2011.23.094On analysis of the load balancing process and the scheduling algorithms of Linux Virtual Server(LVS). This paper proposes an improved algorithm. The system resource type and the server weight coefficient is taken into consideration. It analyzes the load condition of real servers in server cluster according to the standard deviation of the weighted server load and schedule the load balancing by means of adjusting the weight coefficient of servers dynamically and the improved minimum connection schedule algorithm. Experimental results prove the effectiveness of this algorithm.
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Computer Engineering. 2011, 37(23): 282-283,290. https://doi.org/10.3969/j.issn.1000-3428.2011.23.095To the problem that the Shape-adaptive Discrete Cosine Transformation(SA-DCT) method gains poor coding efficiency in low bit rate, and it results in significantly blocking effect in the reconstructing image, it presents coding system frame based on Shape-adaptive All Phase Biorthogonal Transform(SA-APBT). It uses APBT instead of DCT. Experimental results show the method can gain better coding efficiency in low bit rate as well as reduce the blocking effect significantly.
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Computer Engineering. 2011, 37(23): 284-287. https://doi.org/10.3969/j.issn.1000-3428.2011.23.096This paper proposes a cartoon figure design method based on evolutionary computation. Binary tree coded structured Genetic Algorithm(GA) is implemented into the cross and mutation of uneven scale expression. The evolved uneven scale expression is used for the transformation of the original component, which produces a variety of components. The components of the model is coded and stored in the database, and the modified Shuffled Frog Leaping Algorithm(SFLA) is executed for making different combination scheme. Experimental results prove the validity of the design method.
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Computer Engineering. 2011, 37(23): 288-290. https://doi.org/10.3969/j.issn.1000-3428.2011.23.097This paper presents and realizes a rapid carry adder based on carry forecast between groups to improve the speed of the large numbers adder in some cryptography systems. The large numbers is divided into many groups, the delay of carry-chain is reduced by carry lookahead in group. The group addition operation of different carry state is finished by carry forecast between groups. The addition sun of different carry forecast state is selected as the final result based on the carry state. Performance analysis shows that the computing speed of the carry adder is faster when realizing the 1 024 bit large numbers add operation.
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Computer Engineering. 2011, 37(23): 291-292. https://doi.org/10.3969/j.issn.1000-3428.2011.23.098The design based on Maya is less studied. Owing to the particularity of Maya system, it modulates the concurrent control mechanism of Mel modeling instruction sequences through based on the characters and the priority of types of modeling instructions, overcome the disadvantages of traditional token ring mechanism and solve some conflict between multi-user coordination using Maya. It uses Maya WinSocket and C++ API technologies, and extends Maya collaboration design function through plug-ins, and demonstrate its validity through achieving a collaboration example based on LAN.
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