20 August 2009, Volume 35 Issue 16
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Computer Engineering. 2009, 35(16): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2009.16.001This paper proposes a fine-grained radio-map localization based information security boundary in sensor network. In off-line training phase, discrete Probability Density Functions(PDF) are used to characterize the Received Signal Strength(RSS), to build fine-grained radio-map and to define the security boundaries. In on-line positioning phase, Position Probability Matrix(PPM) is proposed to describe location estimations. The estimations of different observers, of different time can be fused by matrix operations. Bayesian filter is proposed to dynamically track positions of mobile targets. Experimental results show that high security determinant accuracy is achieved when the transition interval is set as 1 meter and 2 meters.
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Computer Engineering. 2009, 35(16): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2009.16.002In text-independent Support Vector Machine(SVM) speaker verification, impostor selection for SVM training directly determines its efficiency and performance. This paper proposes two Gaussian Mixture Model(GMM)-based methods for impostor selection. By GMM likelihoods, the most similar impostors to the target speaker are selected for SVM training, which makes the target speaker models more discriminative. Experiments on text-independent SVM speaker verification in NIST’04 1side-1side data show significant improvement.
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Computer Engineering. 2009, 35(16): 7-9. https://doi.org/10.3969/j.issn.1000-3428.2009.16.003This paper proposes a policy refinement model applied to policy-based QoS management in DVB-RCS system. A refinement scenario is provided to describe the goal refinement process. Based on Linear Temporal Logic(LTL), the model derives lower-level policies from higher-level goals to ensure the correctness, rationality and consistency of the whole policy refinement process. The model can be used to guild the system function planning and designing in system design period and offer network manager a mapping method between high-level policies and system device behavior.
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Computer Engineering. 2009, 35(16): 10-13. https://doi.org/10.3969/j.issn.1000-3428.2009.16.004This paper defines the concepts of emergency relation niche based on the dynamic and relative characteristics in emergency environment, discusses the risk intrusion mechanism, granular and discernible characteristics of relation niche, and presents the discernible rule of the relation niche. The example of reservoir flood prevention water level operation system shows the validity and engineering practicability of the relation niche theory. The relation niche theory results from syncretizing multiple disciplines and utilizing cross-fields technology and method, and provides a new idea and method to study the emergency and the emergency management.
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Computer Engineering. 2009, 35(16): 14-16. https://doi.org/10.3969/j.issn.1000-3428.2009.16.005Due to the traditional trajectory model that composed of the Euclidean or linear reference coordinates sequence can not present the implied semantic information of the background geographic information, it impedes the knowledge discovery on the trajectories. The paper proposes a semantic based trajectory knowledge discovering method. It clusters the original GPS x, y coordinates that have the same spatial relation with the predefined key point of the application into one key area at first. The trajectory is depicted using the clustered key area sequence. The regular expression is used to analyze the trajectory. Experiment shows it contributes to simplify the knowledge discovery process.
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Computer Engineering. 2009, 35(16): 17-19. https://doi.org/10.3969/j.issn.1000-3428.2009.16.006There are two problems in static storage resource management that its storage resource utilization is inefficient and it can not meet the requirements of multiple-class applications. This paper designs and implements a virtual storage system named ASD(Allocate-on-demand Storage Device) to solve the problems, which uses the allocate-on-demand policy to relieve the problem of underutilization of storage resource, and uses the dynamic mapping mechanism to manage storage resource in accordance with the access characteristics of applications. The results of test indicate that, compared with the static management method, the performance and resource utilization of Linux ext2 file system based on ASD platform has distinguished improvement.
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Computer Engineering. 2009, 35(16): 20-22. https://doi.org/10.3969/j.issn.1000-3428.2009.16.007This paper studies copy-transform-move forgery and proposes a detection method. The method is based on matching Scale Invariant Feature Transform(SIFT) points in the same image. The method designs a fast matching method to find matching points. The forged regions grow up stepwise based on an appropriate region growing strategy with matching SIFT points as seed-points. The method is robust to common retouch tools and JPEG compression.
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Computer Engineering. 2009, 35(16): 23-24. https://doi.org/10.3969/j.issn.1000-3428.2009.16.008There is no report about haze which is dealt with as thin cloud in NASA MODIS products. Based on MODIS data, by using .NET distributed architecture, combined with MatlabCOM, ArcEngine and other components, this paper establishes regional haze monitoring system, introduces the design idea of the system and its haze retrieval algorithm. It shows good competence from the monitoring results of some haze days in North China.
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Computer Engineering. 2009, 35(16): 25-28. https://doi.org/10.3969/j.issn.1000-3428.2009.16.009Aiming at Considering the complexity of Job-shop scheduling problem, this paper proposes Genetic Reinforcement Leaning(GRL) algorithm to solve it. Several stochastic variables are introduced to transform the Job-shop scheduling problem into sequential decision-making problem, and the model environment is built through simulation to obtain system performance indices and ensure the feasibility of solution. An algorithm integrating multi-Agent Q-Learning algorithm with Genetic Algorithm(GA) is designed to solve Job-shop scheduling problem. GRL algorithm is validated by simulation and optimization experiment results.
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Computer Engineering. 2009, 35(16): 29-31. https://doi.org/10.3969/j.issn.1000-3428.2009.16.010Software test is an important way to improve software quality assurance. Automatic test data generation is an important composition of test automation. This paper introduces a technique of automatic test data generation based on regular expressions. The data generated by this kind of techniques are random, can be controlled, can be defined, meaningful, error-free, and other characteristics. especially large object/special types are supported in this technique. It can solve the problem in automatic test data generation and has better expansibility.
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Computer Engineering. 2009, 35(16): 32-34. https://doi.org/10.3969/j.issn.1000-3428.2009.16.011It is different from the traditional road model, the model of road based on Geographic Markup Language(GML) is adapt to the management fields on road infrastructure. This paper analyzes the characteristic of the composing elements of road and the requirements of management, builds the spatial-attribute integration model for road infrastructure based on the GML schema and analyzes the applied prospect of these models.
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Computer Engineering. 2009, 35(16): 35-38. https://doi.org/10.3969/j.issn.1000-3428.2009.16.012Aiming at the problem that existing algorithms of modern storage systems can not adapt to the special storage systems environment, this paper proposes a Service Time Based Weighted Fair Queuing(STB-WFQ) schedule algorithm which assigns the service resource of storage systems directly based on the service time of every request. Compared with other methods, the algorithm is the fairest in the storage environment. Its performance is very close to the theory limit of the fair schedule algorithms, and can maintain stabilization when the workload of the storage systems is changed.
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Computer Engineering. 2009, 35(16): 39-41. https://doi.org/10.3969/j.issn.1000-3428.2009.16.013Sensitive Information Retrieval(SIR) is a hotspot in research of secure multi-party computation. But the existing methods of SIR method can not protect user’s information very well during query. This paper introduces the oblivious third party, indistinguishable concept and the assumption of combination commutative encryption in semi-honest model. A SIR method based on sharing of least information is proposed, which can apply to documentary data retrieval efficiently. Analysis and proof on security and correctness of the method are presented.
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Computer Engineering. 2009, 35(16): 42-44. https://doi.org/10.3969/j.issn.1000-3428.2009.16.014Focusing on the widely-used WGS-84 reference frame, this paper presents the object model of spatial reference frame, spatial position, and coordinate conversion, using the UML-based object-oriented modeling paradigm. The UML class diagram is used to visualize the object definitions, hierarchies, and associations of the models. The UML activity diagram and sequence diagram are used to describe the algorithms of coordinate conversions.
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Computer Engineering. 2009, 35(16): 45-47. https://doi.org/10.3969/j.issn.1000-3428.2009.16.015An efficient incremental outlier pattern detection algorithm is proposed based on the foundation of k-nearest local outlier pattern detection algorithm and segmentation. Time series data are segmented using series important point in this algorithm. Outlier pattern is detected by local outlier detection technique. When some new data points are inserted, neighbors segment pattern is changed and incremental outlier detection algorithm only refreshes limited number of their nearest neighbors pattern. The outlier pattern can be efficiently detected from time series by this algorithm.
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Computer Engineering. 2009, 35(16): 48-50. https://doi.org/10.3969/j.issn.1000-3428.2009.16.016With the application of large-scale database in the background, a distributed database accessing platform based on multi-Agent is constructed. Distributed semantic caching is studied, and an intelligent pre-fetching algorithm in Agent-based platform is proposed. A new blackboard model is designed to realize the communication between Agents. The test on large-scale database system shows that the statistic query performance has been improved markedly.
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Computer Engineering. 2009, 35(16): 51-53. https://doi.org/10.3969/j.issn.1000-3428.2009.16.017According to data characteristics of the Rough Relational Databases(RRDB), a method for storing uncertainty data is put forward. An approach to index uncertain data is proposed based on Hamming distance. A query method is presented by using the similarity degree calculated between the data entered by users and the data being queried in RRDB based on the concepts of upper and lower approximation of rough sets. The theory methods mentioned above are combined, and the query model of RRDB is constructed. And an algorithm for querying data in RRDB is described and illustrated by using an analysis example. The real world example shows that the proposed approach is useful and effective.
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Computer Engineering. 2009, 35(16): 54-55. https://doi.org/10.3969/j.issn.1000-3428.2009.16.018Aiming at the problem that extended File Allocation Table(exFAT) file system will read a large number of invalid data when accessing FAT information, this paper proposes an Optimization Model(OM). OM can effectively prevent invalid data, speed up the pace of access files and spend the least. In order to find out the FAT information as soon as possible, OM not only establishes File-Cluster-Lists(FCL), which saves all FAT Information of readed files orderly, but also set up File-Information-Blocks(FIB) in RAM for saving its entrance address. Experimental result shows that the greater FAT-dispersion is the greater effect of optimization of speed and efficiency.
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Computer Engineering. 2009, 35(16): 56-58. https://doi.org/10.3969/j.issn.1000-3428.2009.16.019This paper presents high-dependable software design model and algorithm used in space-robot software. The software errors in the space-robots are divided into two categories: the program block model and algorithms build on it are designed for the element level, and the distributed adaptive redundancy model and related algorithms are used to detect the system level errors. The cooperation leads to a complete error detection coverage. The model and algorithm is applied effectively.
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Computer Engineering. 2009, 35(16): 59-61. https://doi.org/10.3969/j.issn.1000-3428.2009.16.020Focusing on the scientific and technological resources retrieval problems, this paper proposes the structure of the classified retrieval system, and discusses the design and realization of classified retrieval system, including data collection, data classification, classified index strategy, classified query and result sort algorithm. Through the thorough research of classified and distributed retrieval system, it achieves the sharing platform retrieval system of the scientific and technological resources, and by the trial operation of the system, its feasibility and efficiency is verified.
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Computer Engineering. 2009, 35(16): 62-64. https://doi.org/10.3969/j.issn.1000-3428.2009.16.021To solve the problem of RDF existing in the semantic retrieval, a new method is proposed which puts forward a Jena-based Web page ontology extracting and processing method on the common RDF level of ontology. An implementation algorithm based on Jena is given. The algorithm is composed of five parts: extracting the RDF model, setting operation of the different RDF models, querying, modifying, and serialization of the RDF model. The validity of the method is proved with a practical case. Experimental results show that the search time is shortened, and the recall and precision are improved in the semantic retrieval.
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Computer Engineering. 2009, 35(16): 65-67. https://doi.org/10.3969/j.issn.1000-3428.2009.16.022To solve the sparsity problems of recommender systems, a recommendation method is designed by means of the combination of the non-neighbouring sequential pattern mining algorithms and the item-based Collaborative Filtering(CF) recommendation algorithms. By constructing the Markov probability transfer matrix according to the paths weight sum algorithms, it computes the recommendation possibility of resources and recommends to users. Experimental results show that, on the condition of sparse data, it can improve the recommendation quality compared with the traditional item-based Collaborative Filtering recommendation algorithms.
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Computer Engineering. 2009, 35(16): 68-70. https://doi.org/10.3969/j.issn.1000-3428.2009.16.023In memory databases, making good use of the processor caches is of great significance to enhance the performance of memory database. In order to deal with the problem above, based on B+ tree, a cache conscious index called “Hash & Tree Tree(HT Tree)” is proposed. This index, which combines Hash with tree, is constructed for memory database. Result shows that the index can improve the utilization rate of processor caches. It can gain better performance than conventional cache conscious indices.
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Computer Engineering. 2009, 35(16): 71-72. https://doi.org/10.3969/j.issn.1000-3428.2009.16.024Aiming at the instance under actual circumstance that incomplete information system is ubiquitous, this paper puts forward a coherence representation filling method, makes the degree at which their decision is infected by condition attribute of information system object measurable, finds out and fills the object which is close to the object with missing attribute at coherence degree, according to the degree at which the coherence infected. It makes incomplete information system mature. The result is proved to be reasonable and effective.
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Computer Engineering. 2009, 35(16): 73-75. https://doi.org/10.3969/j.issn.1000-3428.2009.16.025Current SQL aggregate functions have evident limitations for computing percentages. This paper proposes two SQL aggregation functions for computing percentages. The two novel aggregation functions are easy to use, have wide applicability and can be efficiently evaluated. They may be used as a framework to study percentage queries and to generate efficient SQL code. Experiments compare the proposed percentage aggregations against queries using SQL/OLAP aggregations. Experimental results show that both proposed aggregations are significantly faster than existing SQL/OLAP aggregation functions.
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Computer Engineering. 2009, 35(16): 76-77. https://doi.org/10.3969/j.issn.1000-3428.2009.16.026Data stream is data sequence with time attribute, and the data continually arrive. There are different applied forms of data stream in practical applications. This paper uses the research approach of application-driven, abstracts various stream models from the concrete applications, extracts two parameters which unify the different data stream models on representation, analyzes the clustering methods of different data stream models, explores and gives a clustering frame of the unified data stream model based on sliding window.
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Computer Engineering. 2009, 35(16): 78-80. https://doi.org/10.3969/j.issn.1000-3428.2009.16.027The precision of the similarity measurement standard in index space is lower, in the existing available similar time-subsequence searching algorithms, the time for I/O of data is longer in the post processing. A non-linear dimensionality reduction technique is proposed, and a new algorithm of similar subsequence search in time series is presented. The precision of the similarity measurement standard in this algorithm is enhanced, and the rate of false match is decreased effectively. Experimental results demonstrate that the algorithm can decrease the amount of data by repeat-estimation effectively and improve the efficiency of the similarity search.
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Computer Engineering. 2009, 35(16): 81-83. https://doi.org/10.3969/j.issn.1000-3428.2009.16.028Aiming at the requirements of applying software engineering to the development of complex system simulation, SPCSS, a software process for complex system simulation is proposed. SPCSS produces the artifacts of requirement model, domain model, boundary model, facade model, application model and architecture model. SPCSS is applied to a gas turbine simulation software development to illustrate that SPCSS conforms to the rules of software development and helps developers naturally move on to analysis, design and implementation from requirements, and get high-quality simulation software step by step.
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Computer Engineering. 2009, 35(16): 84-86. https://doi.org/10.3969/j.issn.1000-3428.2009.16.029This paper uses Network Interface Card(NIC) as serving object during packet forwarding process. Compared with traditional method that uses packet as processing object, this method promotes coequal response weighting of packet forwarding on each port of router. By reducing the system schedule time and eliminating the affection of CPU resource schedule caused by the arrival rate of packet, this model increases the maximal throughput of router and decreases the delay of packet forwarding.
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Computer Engineering. 2009, 35(16): 87-89. https://doi.org/10.3969/j.issn.1000-3428.2009.16.030The data allocation algorithm in P2P streaming media and its evaluation principles are introducted. The problems existed in traditional evaluation method are analyzed, and a novel one is proposed. By using this method, five allocation algorithms are evaluated. Simulation experimental results show this new method can display the quantification results with two dimensional dynamic images in Matlab, and obtain all-around and accurate evaluation results.
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Computer Engineering. 2009, 35(16): 90-92. https://doi.org/10.3969/j.issn.1000-3428.2009.16.031IEEE 802.1X standard named Port-Based Network Access Control(PBNAC) is not fully adopted in actual application of network. Existing PBNAC application mode can not fully meet the need of large scale network deployment. Aiming at this problem, this paper proposes a bridge application mode of PBNAC and analyzes the feasibility of integration of multi-application models in one network. Experimental results validate that this mode is effective.
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Computer Engineering. 2009, 35(16): 93-94. https://doi.org/10.3969/j.issn.1000-3428.2009.16.032This paper proposes a new grid routing protocol based on the energy consumption speed of nodes in Mobile Ad Hoc Networks(MANET). It defines a function to compute the velocity of node energy consumption. The value of this function is used as routing parameter for Floyed algorithm to select the best route. It is validated that this protocol needs less energy consumption of node and achieves long network life compared with the existing protocol.
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Computer Engineering. 2009, 35(16): 95-96. https://doi.org/10.3969/j.issn.1000-3428.2009.16.033Aiming at problems that it is hard to maintain in traditional multicast method, a new end system multicast method based on loop overlay network is proposed. According to the delay between nodes, different delay gathering loops are set up. On this basis, multicast is conducted, which need not build multicast trees for each multicast source, and can adapt dynamic changing for multicast members. Simulation experimental results show this method can make the delay changing smoothly while the nodes number increasing.
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Computer Engineering. 2009, 35(16): 97-100. https://doi.org/10.3969/j.issn.1000-3428.2009.16.034Aiming at the problems that the safety information is easy to collide frequently, and the time delay becomes larger when the vehicle density is high in Vehicle Ad Hoc Network(VANET), an On-Demand Power Control Algorithm(ODPCA) based on VANET is proposed. According to the node locations of background safety information demand, the nodes adjust their send power dynamically. By using the safety information transferred between the vehicles, the driving safety is promoted. Simulation experimental results show this algorithm can reduce the time delay, improve the correct reception rate of safety information, and enhance the safety prewarning function of VANET.
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Computer Engineering. 2009, 35(16): 101-103. https://doi.org/10.3969/j.issn.1000-3428.2009.16.035In order to meet the real-time performance requirement of network communication in industial site monitoring and control tasks, a protocol of wireless monitoring and control network based on IEEE802.15.4a standard is proposed, in which, the token control sublayer manages the wireless channel access by using the token mechanism. It overcomes the shortcomings of the CSMA/CA disordered competition, and ensures the deterministic property of data transmission. The paper introduces protocol stack model, the dynamic creation of logic token ring, and the token self-recovery schemes. The protocol is realized on the hardware platform NanoNET. Experimental results show this protocol can run stably under intense electromagnetic interference environment, and possesses the real-time performance.
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Computer Engineering. 2009, 35(16): 104-106. https://doi.org/10.3969/j.issn.1000-3428.2009.16.036Aiming at the anonymous router problem in network topology exploration, this paper constructs an anonymous router network model based on main properties of Internet. It adopts a similar method like traceroute exploration mechanism to sample the trace in this network model, and generates different sample topologies according to the different rate in dealing with anonymous router. Main properties of these sample topologies are analyzed to quantify the impact introduced by anonymous routers, such as network size, node degree distribution, network path length and betweenness numbers.
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Computer Engineering. 2009, 35(16): 107-108. https://doi.org/10.3969/j.issn.1000-3428.2009.16.037The IEEE 802.16e standard adopts sleep mode to save the energy consumption of the mobile station. This paper proposes an improved sleep mode control algorithm, which dynamically adjusts the sleep period of sleep mode according to the access speed. It compares the IEEE 802.16e standard algorithm and the improved algorithm under four actual models, and the results show that the improved algorithm mode saves substantial amount of energy at low access speed and has the same performance as the standard algorithm at high access speed.
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Computer Engineering. 2009, 35(16): 109-111. https://doi.org/10.3969/j.issn.1000-3428.2009.16.038Reducing the energy consuming can prolong the survival of the networks. In the high density deployment of sensor nodes, under the precondition of the network capability, this paper takes the least nodes into the active state, and makes the other nodes into the low energy consumption of the sleep state. Under the precondition of coverage and connectedness mentioned above, it provides a way in how to select the least working nodes and to compute both meet to the coverage request and connectivity request.
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Computer Engineering. 2009, 35(16): 112-114. https://doi.org/10.3969/j.issn.1000-3428.2009.16.039The Distributed Denial of Service(DDoS) attack developing from Denial of Service(DoS) attack has become one of the major threats to network security. This paper starts from the analysis of TCP backlog, and proposes an algorithm based on TCP Backlog detection. Algorithm analyzes TCP backlog combing with historical connected records, generates features vectors, detects abnormal level of TCP backlog using BP neural networks, determines whether attack happens according to the abnormal level. Experimental result shows that the algorithm can detect DDoS attack quickly and accurately, and prevent the occurrence of DDoS attack effectively.
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Computer Engineering. 2009, 35(16): 115-116. https://doi.org/10.3969/j.issn.1000-3428.2009.16.040This paper discuses about the security against adaptive chosen-ciphertext attack aiming at Rabin-OAEP algorithm. Construction of reasonable interaction between Adversary and Simulator is used to provide the inverse proposition of “Decomposition of large integer N=pq is difficult (for p,q are two large prime numbers), the Rabin-OAEP is secure against adaptive algorithm chosen-ciphertext attack.” Result proves claim that Rabin-OAEP is an security algorithm.
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Computer Engineering. 2009, 35(16): 117-119. https://doi.org/10.3969/j.issn.1000-3428.2009.16.041Encryption is a very effective way to enforce data security, because the database is special in it’s structure, so the security key store and the security dictionary metadata must be effectively managered. This paper proposes a new schema which is based on the metadata store, introduces a new architecture for database encryption system and the way to implement it, and gives it’s main models.
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Computer Engineering. 2009, 35(16): 120-122. https://doi.org/10.3969/j.issn.1000-3428.2009.16.042To support secure group communications in resource constrained Wireless Sensor Networks(WSN), and updating group key does not add the commuincation and computing burden of system when sensors leave or enter the system, besides considering the security requirement of group key management must meet, this paper proposes a security and efficient group key management scheme which only uses polynomial. Comparing with previous group key management schemes, this scheme provides more efficiency and is more suitable to WSN.
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Computer Engineering. 2009, 35(16): 123-124. https://doi.org/10.3969/j.issn.1000-3428.2009.16.043Aiming at new features of the H.264/AVC video coding standard, a bi-watermark algorithm for H.264/AVC low bit-rate video stream is proposed. By embedding the robust watermark into DCT domain and fragile watermark into prediction error motion vectors respectively, the method can jointly achieve both copyright protection and authentication. Experimental results demonstrate that the video watermark scheme can achieve high robustness and good visual quality without increasing the overall bit-rate. The robust watermark can robustly survive some attacks such as Gaussian-noise, low-pass filter, re-encoder and rotation and so on, and the fragile watermark is sensitive to various attacks.
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Computer Engineering. 2009, 35(16): 125-127. https://doi.org/10.3969/j.issn.1000-3428.2009.16.044This paper analyzes the application of public key technology such as elliptic curve in Wireless Sensor Networks(WSN). It introduces the structure of WSN operating system named TinyOS, the development flow of NesC program and the TinyOS based Elliptic Curve Cryptography(ECC) cryptolib named TinyECC. It uses TinyECC to design and implement a light node authentication protocol based on ECC. Analysis results validate that this protocol is feasible in WSN.
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Computer Engineering. 2009, 35(16): 128-129. https://doi.org/10.3969/j.issn.1000-3428.2009.16.045Most digital image watermark method based on transformation region without resisting to geometric attack ability. This paper proposes a zero watermark algorithm resisting to rotation attack based on Radon transform. For rotation causing distortion, it makes use of Radon transform detection algorithm to correct the rotated images and detect whether the test image involves watermark or not, and extracts watermark. Experimental results demonstrate the method can obtain better visual effect, and it is robust to all kinds of rotation attacks and some mage degradation process such as adding noise, cropping, filtering and JPEG compression.
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Computer Engineering. 2009, 35(16): 130-132. https://doi.org/10.3969/j.issn.1000-3428.2009.16.046This paper proposes a digital watermark algorithm resisting to geometric distortions. The max smooth area of the image is obtained according to the results of edges detection and the entropies of the image’s blocks, and the histogram of the area is equalized via exact histogram specification approach to the desired shape. In order to improve the accuracy of watermark detection and the fidelity degree of the image watermark embedded in, the serrate shape is utilized as the digital watermark. Experimental results show that the algorithm yields high fidelity degree and relatively high robustness to geometric distortions, and it obtains high tolerance to several signal processing approaches including linear filtering, nonlinear filtering, the addition of Gaussian noise, the addition of salt-and pepper noise and JPEG compression.
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Computer Engineering. 2009, 35(16): 133-134. https://doi.org/10.3969/j.issn.1000-3428.2009.16.047This paper proves that the success rate of slide-algebraic attack 1 algorithm on KeeLoq cipher is only 2-64. To solve this problem, this paper analyzes the relationship between the number of slide pairs and success rate, proposes an improved method to the slide-algebraic attack 1. By reducing the number of slide pairs used in building algebraic equations to two, the success rate is improved to 0.632, and the computation complexity is decreased from 278 CPU clocks to 273 CPU clocks.
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Computer Engineering. 2009, 35(16): 135-137. https://doi.org/10.3969/j.issn.1000-3428.2009.16.048This paper proposes a reversible information hiding algorithm which can recover the original image without any distortion from the marked image after the hidden information being extracted. It uses the property that the difference between adjacent pixels is always small and utilizes the difference matrix to do the original image preprocessing, amends and maps the margin matrix to the original image to realize information hiding. Theory analysis and simulation experiment prove that the algorithm enhances the payload while guaranteeing good invisibility.
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Computer Engineering. 2009, 35(16): 138-139. https://doi.org/10.3969/j.issn.1000-3428.2009.16.049By integrating the concepts of self-certified public key and signcryption, a secure and efficient self-certified signcryption scheme from bilinear pairings is proposed. It can guarantee the confidentiality and authenticity when the message is transmitted and prevent certificate authority to personate the user. The verifier can verify the authenticity of public key and validate signcryption simultaneously. The scheme is more efficient than the existing ones in terms of communication overheads and computation cost. It have more practical value in applications of E-commerce and other fields.
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Computer Engineering. 2009, 35(16): 140-142. https://doi.org/10.3969/j.issn.1000-3428.2009.16.050The security flaws of two provably-secure certificateless signature schemes in the random oracle model and a provably-secure certificateless signature scheme in the standard model are analyzed. It is found that the three schemes are all insecure against public key replacement attack. In this attack, an adversary can generate a new public key satisfying legitimate signatures created by the legitimate signer. In order to avoid these flaws, an improvement measure is proposed, which can resolve the security problems existing in the original schemes.
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Computer Engineering. 2009, 35(16): 143-144. https://doi.org/10.3969/j.issn.1000-3428.2009.16.051The middlewares used in software systems is not secure. Aiming at this problem, this paper designs four kinds of wrappers, which let these middlewares run under secure environment, and provides the control of good granularity among the middlewares, the middleware and other system resources. It researches the expression methods of these wrappers, uses box-π calculus to describe these wrappers and secure encapsulation process, and analyzes the security of each wrapper.
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Computer Engineering. 2009, 35(16): 145-147. https://doi.org/10.3969/j.issn.1000-3428.2009.16.052Based on Signcryption KEM-DEM hybrid signcryption construction, a formal definition of signcryption key encapsulation in insider security mode is proposed. In the definition, a random tag and a verification algorithm are introduced to provide the insider security of the new key encapsulation. Based on the formal definition, this paper discusses the confidentiality security and unforgeability security in concept of provably security. The security models based on attack games are proposed.
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Computer Engineering. 2009, 35(16): 148-150. https://doi.org/10.3969/j.issn.1000-3428.2009.16.053This paper improves the Digital Rights Management(DRM) model which based on the trust model in P2P networks, puts forward a DRM model based on friend peer in P2P networks. This model employs Shamir’s k-threshold secret sharing method, uses friend peer storing private key share, and consequently avoids the problems raised by using the trust model. Analysis and simulation experimental results show that, compared with the DRM model based on the trust model, the information traffic among peers of this model can reduce greatly, and the computational complexity and practicality have been greatly improved.
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Computer Engineering. 2009, 35(16): 151-153. https://doi.org/10.3969/j.issn.1000-3428.2009.16.054This paper builds up a covert channel under Windows network protocol stack based on Network Driver Interface Specification(NDIS) Intermediate Driver(IMD) technology. Application program can communicate with outward by this channel whose position is lower than control of firewall, and it can read and write data directly from NIC. It analyzes the reason the firewall may be bypassed, which is caused by lack of protection for the network, and discusses how to prevent this kind of attacks.
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Computer Engineering. 2009, 35(16): 154-155. https://doi.org/10.3969/j.issn.1000-3428.2009.16.055This paper proposes a database intrusion detection system based on data mining. An improved Apriori _ids algorithm is adopted by the system which can get the set of frequent item sets by scanning database one time easily. The system has such a fine-grained detection which can examine malicious database operations and the users’ abnormal behavior at transaction level. Experimental results show the system improves the production efficiency of frequent item sets and the knowledge regular library.
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Computer Engineering. 2009, 35(16): 156-158. https://doi.org/10.3969/j.issn.1000-3428.2009.16.056Aiming at the security question of information switching between server and smart card, a new channel encryption scheme via using the combination of Logistic chaotic sequence and 3DES is proposed to secure the information switching between server and smart card. Engineering sample shows that scheme can overcome the defect of traditional method, such as long information switching time and vulnerable to plaintext attack, and implement security information switching between smart card and server.
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Computer Engineering. 2009, 35(16): 159-160. https://doi.org/10.3969/j.issn.1000-3428.2009.16.057The chaotic properties of chaotic system such as ergodicity, mixing and sensitive dependence on initial conditions and system parameters, are corresponding with some important properties of cryptosystems. This paper makes a deep analysis for its sensitivity caused by structure parameter and initial value, and gains that chaotic sensitivity effect is an accumulable course. It divides chaotic sequence into anterior sequence and latter sequence, and makes a criterion for them. This paper explores two different types of application to encrypt image using sensitivity of chaotic sequence.
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Computer Engineering. 2009, 35(16): 161-163. https://doi.org/10.3969/j.issn.1000-3428.2009.16.058To improve the detection efficiency of clone attack, which is one of the fields of the Wireless Sensor Network(WSN) in security threats, and prolong the survival time of the network, a new clone attack detection technique, N_RAD protocol, is proposed, it introduces a new type of detection nodes that works parallels with ordinary sensor nodes. Simulation result shows that those nodes improve the detection efficiency, make the energy of the network consume equally, thus prolong the survival period. Compared to existing clone attack detection attack protocol, N-CAD protocol shows better performance.
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Computer Engineering. 2009, 35(16): 164-166. https://doi.org/10.3969/j.issn.1000-3428.2009.16.059F5 steganalysis uses the shrinkage and compares the differences between estimation of the cover-image histogram and the stego-image to realize detection. This paper presents improved F5 algorithm to resist such detection based on the characteristic of F5 steganalysis. It can eliminate a part of surplus 0, elevate embedding efficiency and prevent the shrinkage. Experiment on the standard images shows the improved algorithm can get parameters close to the cover-image, and resist F5 steganalysis.
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Computer Engineering. 2009, 35(16): 167-169. https://doi.org/10.3969/j.issn.1000-3428.2009.16.060Aiming at the problem that the reliability and real-time requirement for eliminating cast shadow of moving vehicles are hard to compatible in traditional way, a new method based on local texture is proposed. Through analysis of the physical model of moving shadows, the local texture is proved to be illumination invariant. The distribution of improved LBP texture is discussed and a significant test is performed to classify each moving pixel into foreground object or moving shadow according to this theory. Intensity constraint and geometric heuristics are imposed to further improve the performance. Experiments on different scenes suggest that effective detection rate of the proposed method is over 90 percent, and the new method is still effective for moving vehicles with lower intensity and can satisfy the requirement of real-time processing.
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Computer Engineering. 2009, 35(16): 170-172. https://doi.org/10.3969/j.issn.1000-3428.2009.16.061A novel distance measuring technology is proposed, which uses Fuzzy Inference System(FIS) trained by Adaptive Neural Fuzzy Inference System(ANFIS) to build the model that maps Received Signal Strength Indicator(RSSI) into the correct Transmitter and Receiver(T-R) distance. It is feasible proved by simulate experiments in which fuzzy distance measuring is planted into single target tracking based on 3-points localization.
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Computer Engineering. 2009, 35(16): 173-174. https://doi.org/10.3969/j.issn.1000-3428.2009.16.062A new two-subpopulation Particle Swarm Optimization(PSO) algorithm is proposed. The information of search space is taken full advantage in the algorithm. The search rang is extended through main subpopulation particle swarm and assistant subpopulation particle swarm, which search direction are inversed completely. Without increasing the size of particle swarm, the optimal precision of high dimension functions is improved and the risk of trapping into local optima is decreased effectively. The efficiency of the algorithm is verified by the simulation results of three benchmark functions and the comparison with two classical PSO algorithms.
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Computer Engineering. 2009, 35(16): 175-177. https://doi.org/10.3969/j.issn.1000-3428.2009.16.063An algorithm is presented to measure atmospheric visibility by using a video camera, which is the equipment for monitoring the traffic. A series of targets with known distances are used. The image which encompasses the targets is captured from video cameras, and impulse noise is removed by a median filter. The area of first target can be divided up from the image by using the algorithm of sum of absolute differences, and the other targets can be segmented by known correlation position with the first target. The feature of the segment portion is extracted from the contrast of the edges of the targets which is measured with Kohler’s thresholding technique. The exponential curve is fitted with the data of the feature and the known distance of the targets. The visibility is decided by the contrast threshold recommended by international commission on illumination. Experimental results show that the algorithm is effective and robust.
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Computer Engineering. 2009, 35(16): 178-179. https://doi.org/10.3969/j.issn.1000-3428.2009.16.064This paper defines a different distance measurement between points of inner class and points of different ones to replace the Enclidean distance measurement through introducing an supervised learning strategy. This paper realizes an improved Laplacian Eigenmap algorithm and puts the lower dimension results as the input of BP neural network to realize classification. Experimental results indicate that the improved Laplacian Eigenmap algorithm reduces the training time of BP neural network and has a better classification result.
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Computer Engineering. 2009, 35(16): 180-182. https://doi.org/10.3969/j.issn.1000-3428.2009.16.065Owing to low classification accuracy and high memory overhead of the normal classifier, a Pattern Classifying Machine(PCM) named tsPCM based on Multiple Attractor Cellular Automata(MACA) for Distributed Data Mining(DDM) is designed, by changing the characterization of a MACA to two stage with two linear operators of Dependency String(DS) and Dependency Vector(DV), and employing Genetic Algorithm(GA) formulation. Plentiful experimental results prove the potential of tsPCM. Its classification complexity is declined from O(n3) to O(n), and it has the respect to excellent classification accuracy and low memory overhead established the availability of the classifier to manipulate the distributed data mining.
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Computer Engineering. 2009, 35(16): 183-185. https://doi.org/10.3969/j.issn.1000-3428.2009.16.066For processing training patterns with imprecise class labels, an adaptive fuzzy k-Nearest Neighbor(k-NN) classifier based on Transferable Belief Model(TBM) is presented. Decision about the true class membership of a pattern can be made to be classified by the combination of TBM, fuzzy sets and possibility theory and the application of the pignistic transformation. The parameters in the classifier are tuned automatically by minimizing error functions through gradient descent. Numerical simulations results show that the classifier has low classification error rates and high robustness.
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Computer Engineering. 2009, 35(16): 186-188. https://doi.org/10.3969/j.issn.1000-3428.2009.16.067This paper presents a face recognition method based on Binary Edge Map(BEM) and Support Vector Machine(SVM). It uses BEM as face representation and employs SVM as face classifiers. The BEM is extracted using Locally Adaptive Threshold(LAT) method. Experimental results show that a face recognition rate of 92.73% can be achieved on 165 Yale face images and 95.62% can be achieved on 798 AR images, indicating that the proposed approach is robust to varying illumination.
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Computer Engineering. 2009, 35(16): 189-191. https://doi.org/10.3969/j.issn.1000-3428.2009.16.068Aiming at the characteristics of fault diagnosis, adopting the advantages of Visual Prolog language in the process of knowledge representation and logical reasoning, taking the catalytic cracking unit with high accidents in process industry as an example, a rule-based fault diagnosis expert system is designed and implemented. Facts and rules, which are the two phrases of Visual Prolog language, are used to realize the compiling of knowledge base and reasoning. Taking the practical application of catalytic cracking unit as an example to verify, cases studies show the effectiveness of diagnosis system, effectively realize the inference and analysis of abnormal conditions, timely find the fault reasons, and provide the appropriate measures for fault handling.
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Computer Engineering. 2009, 35(16): 192-194. https://doi.org/10.3969/j.issn.1000-3428.2009.16.069Traditional fuzzy K-Modes clustering algorithm uses a simple matching dissimilarity measure to compute the dissimilarity between an object and Mode. However, how well Mode is representative of the cluster is not considered in the dissimilarity measure, which may lose some information and result in the cluster with weak intra-similarity. This paper proposes a new dissimilarity measure between an object and Mode, which uses membership degrees of objects to clusters to reflect how well Mode is representative of the cluster. Comparisons with traditional K-Modes and fuzzy K-Modes algorithm illustrate the effectiveness of the new distance measure.
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Computer Engineering. 2009, 35(16): 195-197. https://doi.org/10.3969/j.issn.1000-3428.2009.16.070Aiming at the problem of threat assessment in actual combat area, an improved technique for threat assessment based on intuitionistic fuzzy reasoning is proposed. The triangle membership and non membership functions for input/output state variables are devised, expressions of variables are presented by precisely calculated, and the inference rules of the system which including confidence factors are embedded into assessment system. The threat assessment system based on intuitionistic fuzzy reasoning can go into operation when it has inputs. The validity of the algorithm is proved by actual combat targets data.
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Computer Engineering. 2009, 35(16): 198-200. https://doi.org/10.3969/j.issn.1000-3428.2009.16.071According to the study of the problem of Quality of Service(QoS) multicast routing, this paper proposes a novel multicast routing algorithm based on the improved Genetic Algorithm(GA). Tree structure coding is utilized and crossover and mutation are uniquely designed in this algorithm. The simulation verifies that this algorithm can save the massive decoding operation, and shorten the time for search solution. The convergence rate cannot slow down along with the network scale increasing with the characteristic of restraining and seeking the superior fast.
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Computer Engineering. 2009, 35(16): 201-202. https://doi.org/10.3969/j.issn.1000-3428.2009.16.072This paper analyzes the shortcomings of Bayes and puts forward a better method to improve it. It releases attribute independence assumption of Naive Bayes text classifier. An improved text classification model based on Bayes theorem called stump network is presented to amend the Naive Bayes text classifier. Experiment shows that the revised text categorization model meets the need of text categorization, and improves the performance of former one.
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Computer Engineering. 2009, 35(16): 203-205. https://doi.org/10.3969/j.issn.1000-3428.2009.16.073Aiming at background generation problem of traffic image object detection, this paper puts forward a method of background generation, defines the transportation sequence picture as three states, classifies the transportation sequence picture by using synergetic method, gives different states of transportation picture different weight, and gets the initialized background by using weighting average. Experimental result shows that the effect of this method is ideal.
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Computer Engineering. 2009, 35(16): 206-208. https://doi.org/10.3969/j.issn.1000-3428.2009.16.074To meet the needs of labeling magnetic gradient characteristic of aeromagnetic contour map, methods based on solid-shadow algorithm and directional filtering technique are presented. After relative ubiety of magnetic field data is distilled, two types of graded distribution are obtained by solid-shadow algorithm and directional filtering technique respectively. The results of solid-shadow algorithm and filter-refinement processing make surface gradient feature very sharp and effective, which is valuable for overlap analysis.
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Computer Engineering. 2009, 35(16): 209-210. https://doi.org/10.3969/j.issn.1000-3428.2009.16.075Aiming at the problems that cutting results are easily influenced by initial curve location in traditional CV model, it is integrated with geodesic model, and a novel global optimization CV model based on adaptive local statistic is proposed, which uses minimization energy functions to cut the images, and avoids the problem of convergence in local minima. By using edge functions, the boundary detection is conducted. It can cut the edge with low contrast. Simulation experimental results show this CV model has higher cutting accuracy compared with the existed one.
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Computer Engineering. 2009, 35(16): 211-213. https://doi.org/10.3969/j.issn.1000-3428.2009.16.076Aiming at the problem of low retrieval rate of texture image retrieval system based on basic contourlet transform, a texture image retrieval system based on Contourlet-S transform is proposed. The feature vectors in the system are constructed by cascading the energy and standard deviation of every sub-band in Contourlet-S domain, and the similarity metric is Canberra distance. Experimental results show the retrieval rate of Contourlet-S transform based image retrieval system under the same system structure and decomposition parameter is superior to that of the original contourlet transform with almost same retrieval time.
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Computer Engineering. 2009, 35(16): 214-215. https://doi.org/10.3969/j.issn.1000-3428.2009.16.077In order to cut the reconstructed 3D models in computer aided virtual surgery, a cutting algorithms for 3D surface model in medical images is proposed. By using the mouse to draw an enclosed curve on the model, the bistouries cutting orbit is simulated, which implements the arbitrary mutual cutting in surgery process. Simulation experimental results show this algorithm has better interaction, can obtain well virtual cutting effect, and has the values of application.
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Computer Engineering. 2009, 35(16): 216-218. https://doi.org/10.3969/j.issn.1000-3428.2009.16.078Aiming at the limitation problems in traditional camera calibration methods, a novel camera calibration method based on single rondo surface image is proposed, which uses computer vision, image processing and computer-aided geometric technology to provide enough geometric information for single images to conduct camera calibration. The single uncalibration image including rondo surface and the special calibration block are researched. Simulation experimental results show this method can calibrate the camera effectively, and provide conditions for application technology based on image processing.
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Computer Engineering. 2009, 35(16): 219-220. https://doi.org/10.3969/j.issn.1000-3428.2009.16.079In order to meet the requirement of marine laser gyro inertial navigation system, this paper designs a navigation computer system based on the DSP chip named TMS320C6713B and FPGA. By using FPGA, the count functions of the signal of laser gyro and the output signal of accelerometers are realized, and the communication between DSP and peripheral equipment is accomplished. This system has the structure of single CPU using TMS320C6713B as the core. It can do operation with 64 bit precision and high speed and meet the needs of real-time performance.
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Computer Engineering. 2009, 35(16): 221-223. https://doi.org/10.3969/j.issn.1000-3428.2009.16.080This paper uses hierarchical method and UML statecharts to model an elevator control system and expatiate an approach of implementing the statecharts model with PLC language. By means of encapsulating the composite state into subroutine, and by means of setting or resetting the enable input bit to enable or disable the subroutine to be executed or not to control the transition. The main program of the control system is presented, which takes Siemens PLC as its platform. This program is structural and can be used as a PLC software framework of control system.
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Computer Engineering. 2009, 35(16): 224-227. https://doi.org/10.3969/j.issn.1000-3428.2009.16.081To calculate the availability of integrated avionics based on double-star network, this paper computes the network availability algorithmically, derives analytical expressions and simulates the formula with Matlab for several different redundancy schemes in same double-star network topologies. The design guideline of integrated avionics redundency schemes is proposed according to the results of simulation.
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Computer Engineering. 2009, 35(16): 228-230. https://doi.org/10.3969/j.issn.1000-3428.2009.16.082A fast FPGA placement algorithm which can deal with macro blocks is proposed. It takes advantage of an analytical method to figure out the ideal positions of all the blocks. It adjusts the positions of the blocks by local expansion. The typical simulated annealing algorithm is used to refine the placement at a low temperature. Experimental results show that in comparison with the popular VPR algorithm, the algorithm can deal with macro blocks elegantly and speeds up the placement greatly without deteriorating the quality of final placement.
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Computer Engineering. 2009, 35(16): 231-233. https://doi.org/10.3969/j.issn.1000-3428.2009.16.083This paper proposes a reconfigurable VLSI architecture of 2D-DWT. Because of the fact that data amount in 2D image processing is huge and the chip area is dominated by the size of the on-chip SRAM, a memory optimization technique is proposed to use single-port SRAM instead of dual-port SRAM. In even cycles, the source data are read from the on-chip SRAM and stored to register banks after calculation. While in odd cycles, source data are read from register banks and, after calculation, stored to SRAM. The method can save about 56% of the chip area compared to traditional implementations. Based on the new method, the paper proposes an improved block-based scan pattern which makes the data transport performance between DWT and further-level DWT or tier-1 entropy encoding blocks 20% better.
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Computer Engineering. 2009, 35(16): 234-236. https://doi.org/10.3969/j.issn.1000-3428.2009.16.084According to the large dynamic range of signals, this paper proposes a method of design of digital Auto Gain Control(AGC) based on the chip AD8369 and two-slope filtering technique, which is applied in extracting the amplitude of the signal circuit, as well as the algorithms of digital AGC. The validity of algorithms is verified by the simulation in Matlab, and the result of the test, its analysis of errors and improved method is also given.
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Computer Engineering. 2009, 35(16): 237-239. https://doi.org/10.3969/j.issn.1000-3428.2009.16.085In order to meet the requirements of servo control in small low altitude verifying airship, a servo control system is researched and designed, which uses MSP430F149 singlechip as its core processor. The hardware frame and software flow are introduced. It is implemented on closed loop simulation platform based on PID control strategy. Experimental results show this system has some merits such as low power consumption, compact conformation, and strong capacity of resisting disturbance, it has better performance of tracking.
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Computer Engineering. 2009, 35(16): 240-242. https://doi.org/10.3969/j.issn.1000-3428.2009.16.086This paper introduces the basic firmware development flow of TMS320C6000 DSP application system and proposes a new development pattern based on a monitor resident in the extended Flash of DSP. Results of firmware development of a laser gyro strap-down inertial navigation system show that compared with the basic development pattern, the one based on monitor has such advantages as using simple devices easy to operation, high flexibility. It can promote the development efficiency and solve the in-system maintenance and upgrade problem of application system firmware in which DSP is at the core.
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Computer Engineering. 2009, 35(16): 243-244. https://doi.org/10.3969/j.issn.1000-3428.2009.16.087Aiming at the limitation of energy of Wireless Sensor Networks(WSN) node, this paper proposes an improved ant colony algorithm. The ant pheromone, the energy of the node and delay between the nodes are combined to engender algorithm control gene. Simulation results show that this algorithm can balance energy consumption between nodes in the network and prolong the lifecycle of the whole network, relieve network congestion and reduce the average transmission delay.
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Computer Engineering. 2009, 35(16): 245-247. https://doi.org/10.3969/j.issn.1000-3428.2009.16.088A new Ling Carry-Select Adder(CSA) is desighed. Ling carries are employed as inter-group carries instead of traditional ones. The carry mechanism is generated by using internal connection and parallel prefix logic of node fanout balance. The usual CSA mode is adjusted, which is fit for Ling carry. This adder has the performance of rapidity for Ling adder, and avoids the complexity of logic generation. Experimental results show the speed of this adder is promoted by about 12% compared with Carry-Lookahead Adder(CLA).
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Computer Engineering. 2009, 35(16): 248-250. https://doi.org/10.3969/j.issn.1000-3428.2009.16.089Aiming at the drawbacks that a long mount time and a large RAM disappear in JFFS2 file system, this paper proposes file system based on NFFS Flash chip. It uses JFFS2 and disk file systems for reference, expatiates the mount process and its implementation. Mount test results show that this system has higher loading performance than JFFS2 file system. It is reasonable and feasible.
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Computer Engineering. 2009, 35(16): 251-252. https://doi.org/10.3969/j.issn.1000-3428.2009.16.090Based on the structure of the invalid NAND flash, the classified invalid block management algorithm is proposed. The invalid block management strategy is put forward respectively correspond to the erasing, writing and reading operation of the flash. When writing data to the flash, the written data stored into the NAND flash is simultaneously backup by the external SRAM to prevent data storage error. Experiment which is based on FPGA platform indicates the algorithm can quickly identify the new increased invalid blocks and the consecutive invalid blocks. The written data can be backup.
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Computer Engineering. 2009, 35(16): 253-255. https://doi.org/10.3969/j.issn.1000-3428.2009.16.091Aiming at the characteristics of the traditional virtual camera technology needs driver’s support, this paper proposes a virtual camera development framework based entirely on the DirectShow technology. It analyzes the DirectShow and WDM technology’s features, focuses on discussing the key technology of implementation, and gives a practical application case. Software development based on this framework can reduce the virtual camera’s costs of development and maintenance, and it has good scalability.
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Computer Engineering. 2009, 35(16): 256-258. https://doi.org/10.3969/j.issn.1000-3428.2009.16.092An ontology-based knowledge management system framework is presented, and the design and realization process of main modules and the key technology points are described. Based on domain ontology and the variety of corporation requirement, this framework can maintain the knowledge structure dynamically and realize the dynamic management of corporation knowledge.
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Computer Engineering. 2009, 35(16): 259-261. https://doi.org/10.3969/j.issn.1000-3428.2009.16.093To benefit grounding grids corrosion diagnosis, monitoring lines are suggested to implant on some nodes of the grounding grid in the construction process. A genetic algorithm based method of layout optimization of monitoring lines is put forward. The approach consists of some iteration of a sub-process. The optimum layout of making all of the branches clear with the minimum number of monitoring lines can be worked out. The coding of chromosomes is described. The ways to avoid of the unfeasible solutions in the processes of the initial population forming, crossover and mutation operation are discussed. The method of layout optimization is used on a grounding grid with sixty branches, and the result shows the feasibility of the approach.
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Computer Engineering. 2009, 35(16): 262-263. https://doi.org/10.3969/j.issn.1000-3428.2009.16.094To realize the automation and intelligence of relative treatment for compositon, this paper proposes a Web service automatic composition algorithm based on semantics. It adopts depth first method to compute the semantic similarity among concepts, generates the service composition scheme from request-input to request-output based on the pre-services. Experimental results show that the algorithm fully imposes semantic information of Web services, compared with existing algorithm, it simplifies the course of automatic combination.
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Computer Engineering. 2009, 35(16): 264-266. https://doi.org/10.3969/j.issn.1000-3428.2009.16.095Aiming at classical DS evidence compositive theory, this paper proposes a DS compositive algorithm based on matrix analysis. It uses reasoning in turn to integrate evidences, computes compositive results in the combinations of n group trust function to sovle the problem of evidence conflict. The algorithm uses analysis matrix to overcome the problem of huge calculation and reduce the burden of the node. Experiment uses the data which collected in greenhouse control as simulation objects, comparative result proves the speediness of the algorithm, the computing time is 1/10 of classical DS evidence compositive theory.
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Computer Engineering. 2009, 35(16): 267-269. https://doi.org/10.3969/j.issn.1000-3428.2009.16.096In order to implement instrument configurate quickly during the time of operating, this paper designs a dynamic reconfiguration scheme for Embedded Virtual Instrument(EVI). It uses a dynamic reconfigurable IP as a basic module and dynamically replaced for form system IP during the run to achieve the hardware reconfiguration. The design uses EVI middleware and configuration store to achieve the software reconfiguration. Test results demonstrate that the method can reduce the cost and cycle of exploitation, implement test requirement for different situation.
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Computer Engineering. 2009, 35(16): 270-272. https://doi.org/10.3969/j.issn.1000-3428.2009.16.097This paper introduces a synchronization technology which is developed by the graphic language Laboratory Virtual Instrument Engineering Workbench(LabVIEW), and uses commercial instruments and commercial Global Positioning System(GPS) receiver. It describes the multithreaded programming, choosing the develop tool, system design and programming during the development. As an available and low cost solution, it is proved in the practice that the technology can solve the synchronization of the location and the measurement data easily.
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Computer Engineering. 2009, 35(16): 273-274. https://doi.org/10.3969/j.issn.1000-3428.2009.16.098Based on the task evaluation of English-Chinese Cross-Language Information Retrieval(CLIR) in Text Retrieval Conference(TREC), this paper adopts English-Chinese bidirectional query translation as the dominant strategy and uses English-Chinese queries as the translation object. English and Chinese electronic dictionaries are utilized as the knowledge source to acquire the translation knowledge and combined with the established English-Chinese monolingual Information Retrieval(IR) systems. The whole bidirectional CLIR process can be implemented. Experimental results show that this system is effective.
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Computer Engineering. 2009, 35(16): 275-277. https://doi.org/10.3969/j.issn.1000-3428.2009.16.099Aiming at prescription context services only provides easy inquiry function nowadays, and it is insufficient to meet the requirements of carding and accumulation, this paper proposes similarity model for four aspects of prescription. It introduces set similarity model in prescription’s ingredients, efficacies and functions. String-based similarity model is brought in a model based on statistics and dictionaries is proposed. It excavates inherent correlations among prescriptions, and finishes cluster prescriptions.
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Computer Engineering. 2009, 35(16): 278-279. https://doi.org/10.3969/j.issn.1000-3428.2009.16.100Aiming at the problem of predistortion for memory nonlinear amplifier in predistortion technology, this paper analyzes the structure of digital predistortion and recognization algorithm of common predistortion, improves classical Least Square/Singular Value Decomposition (LS/SVD) algorithm. Improved LS/SVD algorithm can obtain better performance by less resource. Simulation results show the proposed algorithm can realize fast and effective linearization of memory nonlinear amplifier, and improve its performance.
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Computer Engineering. 2009, 35(16): 280-282. https://doi.org/10.3969/j.issn.1000-3428.2009.16.101This paper combines with development and application situation of enterprise system nowday, analyzes business integration of inner enterprise. It proposes a method for business integration based on Enterprise Service Bus(ESB). The method designs system architecture, functions and realization methods of each proportion, and gives a case of its application about transportation manager system. The application result in transpont management system shows that it can solve the problem of information isolated island, decreases the cost of integration and exchange, improves the utilizing rate of IT resource.
【Key words】 -
Computer Engineering. 2009, 35(16): 283-封三. https://doi.org/10.3969/j.issn.1000-3428.2009.16.102In order to veritably display Chinese calligraphy in real time with simple computing and cheap devices, this paper uses F-Tablet hardware system and analyzes the statistical relationship between force information and stroke width to establish the virtual brush model. This model can reduce the time of computing and realize real time alternation. Compared with one-order linear model, ARMA model and fuzzy reasoning model, this model has better writing effect.
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