05 September 2010, Volume 36 Issue 17
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Computer Engineering. 2010, 36(17): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2010.17.001An improved and efficient algorithm is brought up for M-S algorithm computing s-invariants of petri nets. The M-S algorithm executes the linear combination between all the positive lines and negative lines, which increases the complexity of the algorithm and the result maybe not the largest linearly independent set, so the final result is not always the minimal support S-invariants. Improved algorithm proposed in this paper increases the pre-processing of the flow matrix, which significantly reduces the number of linear combination operations, and the final results are minimal support S-invariants. It is theoretical proved that the complexity of the original algorithm is s×t and the improved algorithm complexity is s+t, the complexity is effectively reduced.
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Computer Engineering. 2010, 36(17): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2010.17.002Existing watershed algorithm is sensitive to noise and has over-segmentation problem. Based on previous studies and combining with the current progress, this paper introduces watershed algorithm simulating flood and watershed algorithm simulating rain. It sums up four types of improved methods for watershed algorithm according to defects of the traditional algorithms. Problems and further research aspects of improved methods for watershed algorithm are discussed.
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Computer Engineering. 2010, 36(17): 7-9. https://doi.org/10.3969/j.issn.1000-3428.2010.17.003Evolutionary network is a dynamic changeable network structure. Aiming at the high delay problem of data packet transfer in evolutionary network caused by its software implementation mode, this paper designs an evolutionary router based on network processor. With the embedded CPU’s flexibility and micro engine’s high throughput on packet processing, the evolutionary router can achieve nearly linear speed throughput.
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Computer Engineering. 2010, 36(17): 10-12. https://doi.org/10.3969/j.issn.1000-3428.2010.17.004The key problem in service computing domain is to find target service precisely. Due to not considering the compatibility of task circumstance, the precise of traditional service discovery method can be improved. This paper proposes a task circumstance imported service discovery method, which imports structured concept instance pattern to describe task circumstance. Experimental data shows that the proposed method outperforms others in terms of precision.
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Computer Engineering. 2010, 36(17): 13-15. https://doi.org/10.3969/j.issn.1000-3428.2010.17.005The dominant traffic in a Wireless Sensor Network(WSN) is converge-cast, and a WSN usually adopts tree-type topology to ease data gathering. Owing of these characteristics, this paper presents an improved distributed Time Division Multiple Access(TDMA) scheduling protocol. This protocol builds a spanning tree topology for a WSN in terms of minimum hops to sink or maximal residual energy, and then propose a Near Maximum slot number Method(NMM) and Hop-based Ordering Method(HOM) for slot allocation. Analysis and simulation results show that the protocol adopting either algorithm decreases the data delay and the energy consumption.
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Computer Engineering. 2010, 36(17): 16-18. https://doi.org/10.3969/j.issn.1000-3428.2010.17.006To improve the efficiency of process planning for Body In White(BIW), data mining technology is applied to capture useful process information. Manufacturing resource database, process principle database and process example database are built respectively. Reasoning system based on data mining is constructed. Semantic matching method is used to query parts and welding robots. The association rules are used to select the most reasonable welding type. The Genetic Algorithm(GA) is used to optimize welding path. Application results show the system can manage process information for BIW effectively.
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Computer Engineering. 2010, 36(17): 19-22. https://doi.org/10.3969/j.issn.1000-3428.2010.17.007In dynamic Service-Oriented Grid(SOG) environment, this paper proposes a SRPS service rescheduling strategy for issue of service fault during the execution of workflow application. If fault service is a node on the critical path of Graph of Services(GS), SRPS will adopt performance-based heuristic method to reassign services for remain tasks, otherwise SRPS will adopt stability-based service rescheduling method for single task. Experimental result proves that SRPS is superior to SLACK and AHEFT in higher dynamic SOG environment.
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Computer Engineering. 2010, 36(17): 23-24,27. https://doi.org/10.3969/j.issn.1000-3428.2010.17.008An algorithm of automatic abnormal input data construction is put forward. Based on the result of software binary patch comparison and target function call graph, a fitness function is designed which is used to evaluate all of the individuals in the same population and find and pass excellent individuals down to next generation. Experimental result shows that the algorithm can generate the data that gets or nearly gets to the point of the software vulnerability, and simplify the process that reverse analyzer constructs abnormal software input data.
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Computer Engineering. 2010, 36(17): 25-27. https://doi.org/10.3969/j.issn.1000-3428.2010.17.009On the basis of data flow analysis, this paper translates program into data flow descriptive markers and obtains reach in and out definitions sets of basic blocks through data flow reach-definition anlysis. It establishes relation between function input and output to achieve static understanding. Experimental results demonstrate that string operating functions such as copy routine are correctly identified without extra clue by using this method.
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Computer Engineering. 2010, 36(17): 28-29. https://doi.org/10.3969/j.issn.1000-3428.2010.17.010The traditional test script language and test strategy can not satisfy the test requirement of safety-critical software test. Aiming at this problem, based on the requirement of the safety-critical software testing, this paper proposes a new safety test method, which uses safety test strategy based on scenario-event and designs a new safety test script language based on the new strategy. The safety test simulation results of the train control center of existing line show the validity of the method.
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Computer Engineering. 2010, 36(17): 30-32. https://doi.org/10.3969/j.issn.1000-3428.2010.17.011The traditional Web service discovery mechanism that is based on keywords and simple classification can not satisfy users’ requirements due to the lack of Quality of Service(QoS). Aiming at this problem, a QoS-based Web service discovery model is proposed, in order to support QoS-based Web services publish and discovery, the QoS broker mechanism is introduced into the traditional Web service discovery model. On the basis of these, according to the characteristics of QoS requirements of different users, a QoS-based Web service discovery algorithm is proposed. Experimental results show that the algorithm has higher accuracy.
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Computer Engineering. 2010, 36(17): 33-35,38. https://doi.org/10.3969/j.issn.1000-3428.2010.17.012In traditional Document Frequency(DF) method, the number of a term which is used in a category is the only information for feature selection, wihtout involving the times of a term appearing in a document. For solving the problem, a new feature selection method is proposed in which the Term Frequency(TF) of terms is taken into consider according to the terms’ document frequency, and the Support Vector Machine(SVM) method is used to train the classifier. It is shown by the experiment that considering the term with high term frequency during feature selection can improve the classification performance of the traditional DF method.
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Computer Engineering. 2010, 36(17): 36-38. https://doi.org/10.3969/j.issn.1000-3428.2010.17.013Locally Linear Embedding(LLE) algorithm is sensitive for the number of nearest neighbors, and fails on sparse source data. In order to solve the problem, this paper proposes a new LLE algorithm based on improved distance and united optimization. It introduces a distance measure in Conformal-IsoMap into LLE, and units the two optimization equation of the original algorithm. Experimental results on SwissRoll curve sampling and MINST character database validate the effectiveness of the algorithm.
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Computer Engineering. 2010, 36(17): 39-41. https://doi.org/10.3969/j.issn.1000-3428.2010.17.014When constructing global quadtree database of spatial vector, quadtree vector nodes generation may involve massive spatial data I/O. This paper proposes a construction approach of building spatial vector database based on multi-line merging. It uses the method of external sort to resolve the problem of memory restriction. By using ordered node runs formed naturally by vector lays dividing and applying memory file mapping technique on node runs I/O, the efficiency of vector database construction is ensured. Experimental result proves that the efficiency of the approach is satisfied.
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Computer Engineering. 2010, 36(17): 42-44. https://doi.org/10.3969/j.issn.1000-3428.2010.17.015This paper combines sequential binary tree with Quick Search(QS) algorithm to propose a fast multi-pattern string matching algorithm, which achieves better performance by shifting unmatched characters continuously in the process of multi-pattern matching. It uses jump comparison with unmatched strings to enhance the speed and decrease character matching operations. Experimental results demonstrate that the algorithm constructs more quickly in preprocessing process and its search speed is higher than SMA algorithm. It achieves better performance in the cases of longer string patterns.
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Computer Engineering. 2010, 36(17): 45-47. https://doi.org/10.3969/j.issn.1000-3428.2010.17.016Under LAN environment, this paper implements a distributed file storage system based on Erasure Code. The system consists of metadata server and many file storage nodes. The separation between metadata storage and file data storage enhances efficiency in file access. It applies Erasure Code effective redundancy storage technology into divide and code file to enhance reliability of file, uses MD5 message digest technology to ensure the integrity of file. Test results for files whose size is about 30 MB to 600 MB show that this system has better reliability, safety and resource utility.
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Computer Engineering. 2010, 36(17): 48-50. https://doi.org/10.3969/j.issn.1000-3428.2010.17.017Aiming at the sparsity of user rating data and the drawbacks of traditional similarity measure methods, a novel recommendation algorithm based on cloud model is proposed. It predicts the item ratings that users have not rated by calculating the item similarity based on the cloud model. It calculates the similarity of users by using the cloud model to find the target users’ neighbors. Experimental results show that the algorithm can not only efficiently lower sparsity of rating data but also improve the recommend quality of the recommender system.
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Computer Engineering. 2010, 36(17): 51-53,56. https://doi.org/10.3969/j.issn.1000-3428.2010.17.018Aiming at the problem of imprecise descriptions for bug patterns in automatic bug pattern extraction methods, this paper uses Program Dependence Graph(PDG) to descript context-sensitive bug patterns. It gives an automatic method to extract bug patterns induced by bug fix, by comparing adjacent software versions. The method is applied to the Apache project, and 316 valid bug patterns are extracted. 13 suspicious unknown bugs are found after inspecting Apache version 2.2.8 with these patterns, which proves the effectiveness of the method.
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Computer Engineering. 2010, 36(17): 54-56. https://doi.org/10.3969/j.issn.1000-3428.2010.17.019At present, there are no researcheres using matrix method to design attribute reduction algorithm based on Skowron discernibility matrix. Aiming at this problem, in this paper, a new matrix is proposed, and an attribute reduction based on the new matrix is provided. It is proved that the new attribute reduction definition is the same as that based on Skowron discernibility matrix. It uses the matrix of attribute to define the significance of attribute, and designs a new attribute reduction algorithm based on Skowron discernibility matrix. Example proves the validity of the algorithm.
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Computer Engineering. 2010, 36(17): 57-59,62. https://doi.org/10.3969/j.issn.1000-3428.2010.17.020Based on increment update algorithm, by assigning different time weight for different data and introducing min-support threshold and its adaptive adjusting method, this paper proposes a new algorithm named Apriori+. The item set are given different time weights which reflect the objective rules make the frequent item set changed when the database is updated, so that the association rules are more practical.
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Computer Engineering. 2010, 36(17): 60-62. https://doi.org/10.3969/j.issn.1000-3428.2010.17.021Bounded model checking is mainly used to detect the property in the path. This paper proposes an encode method which is used to extend the LTL formulas in path, then bounded model checking can be reduced to the problem of whether the propositional logic formula is satisfiable or not, and SAT checking tool can be used to complete the process. The reducing process is proved to be correct and complete. An specific example is given to show the validity of the method.
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Computer Engineering. 2010, 36(17): 63-65,68. https://doi.org/10.3969/j.issn.1000-3428.2010.17.022The essence of software vulnerability is to exploit and affect system security. Different software vulnerabilities cause different effects to system and the severity is various as well. Based on the critical research of some typical taxonomy relative to software vulnerability effects, the direct effect and final effect and relationship between are analyzed. The key factor of software vulnerability direct effect is demonstrated and the software vulnerability analysis model based on effect width and depth is proposed. The direct effect modes are analyzed including system level, user level and file level. The design and implementation of model on active defense system for large scale network of mission-critical domain are given.
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Computer Engineering. 2010, 36(17): 66-68. https://doi.org/10.3969/j.issn.1000-3428.2010.17.023In order to realize full coverage for test case, this paper gives an improved pairwise combinatorial test data auto generation algorithm. The initial test data set is produced based on matrix, and extra test data is added into the initial test data set based on the thought of composite matching. Experimental results show that the algorithm is simple and effective, and it has the characteristics of less producing test data and time consumption.
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Computer Engineering. 2010, 36(17): 69-71. https://doi.org/10.3969/j.issn.1000-3428.2010.17.024A definition of attribute significance is proposed based on knowledge rough entropy in ordered information systems, and important properties are obtained. It can be found that using the definition can measure uncertainty of an attribute set in the ordered information systems. A heuristic algorithm for attributes reduction is acquired in the systems. An example illustrates the validity of this algorithm, and results show that the algorithm is an efficient tool for data mining, and provides an important theoretical basis for knowledge discovery in ordered information systems.
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Computer Engineering. 2010, 36(17): 72-73,76. https://doi.org/10.3969/j.issn.1000-3428.2010.17.025How to select original clustering cores of K-Means and DBSCAN is important to the result of data mining. Aiming at the problem, this paper improves the method of selecting original clustering cores via entropy. It applies improved K-Means and DBSCAN to the intrusion detection system, and does anomaly detection test on a common set of records in the system. Experimental result proves that the method is effective.
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Computer Engineering. 2010, 36(17): 74-76. https://doi.org/10.3969/j.issn.1000-3428.2010.17.026In Networked Automatic Testing System(NATS), this paper presents a database model which combines DataBase Management System(DBMS) with file system. Relying on this model, it designs and implements a database middleware of NATS based on Java technology. The middleware provides a unified Application Programming Interface(API) for user, provides a general CRUD function and data access service of, enhances scalability and reusability and reduces the burden of maintenance and upgrade for NATS.
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Computer Engineering. 2010, 36(17): 77-80,86. https://doi.org/10.3969/j.issn.1000-3428.2010.17.027
In order to satisfy the practice management requirement of inland small and medium enterprises, this paper designs a lightweight Radio Frequency IDentification(RFID) middleware. Its architecture is between being centered with basic framework and centered with application program, and it simplifies the Application Level Event(ALE) structure of Electronic Product Code(EPC) system. Based on Application Program Interface(API), it implements lightweight middleware by integrating and filtering thought of database. This lightweight middleware has simple structure, short development cycle, and it is easy to maintain and extend at later period.
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Computer Engineering. 2010, 36(17): 81-83. https://doi.org/10.3969/j.issn.1000-3428.2010.17.028
According to the insufficiency of Internet of Things(IOT) on information transmission, a trusted anonymous information transmission protocol of IOT is proposed with trusted computing technology. In the protocol, information servers of things encode the details of things layer by layer according to the order of response nodes. In the transmission process, the data are decoded at every passed node until the local ONS server data are totally decoded. Meanwhile, the respond nodes can tell whether the received information is changed by some relevant information. The analysis shows that this protocol is safe, anonymous, trusted, attack-resistant, etc.
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Computer Engineering. 2010, 36(17): 84-86. https://doi.org/10.3969/j.issn.1000-3428.2010.17.029
This paper designs Things Oriented Architecture(TOA) and Things Oriented Communication(TOC) middleware which is consist of device Agent, TOC client, and TOC server. TOC is capable of isolating the innumerable diversity of Internet of Things(IOT) objects and providing a unified interactive service and platform by applying Extensible Messaging and Presence Protocol(XMPP) and Pipe & Filter design mode. It implements TOC in the hospital medical trash management system. The results are very promising. It indicates that TOC can provide a unify system integration platform and enough flexible in IOT objects implementation.
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Computer Engineering. 2010, 36(17): 87-89,92. https://doi.org/10.3969/j.issn.1000-3428.2010.17.030
Aiming at the security problem of maliciously tracking, amending and impersonation existing in original Radio Frequency IDentification(RFID) middleware, this paper presents a RFID middleware reconfigurable security framework. It uses Service-Oriented Architecture(SOA) and Open Service Gateway initiative(OSGi) plug-in architecture to reduce coupling between some component, enhance reusable, and research and binding component service. It goes on security state monitoring by life cycle management to realize real-time dynamic operation management. Test result shows that this framework has the characteristics of dynamical expansion, centralized management and complete modular, it also can enhance application efficiency of RFID, and strengthen reliability and security.
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Computer Engineering. 2010, 36(17): 90-92. https://doi.org/10.3969/j.issn.1000-3428.2010.17.031
The architecture of UHF Radio Frequency Identification(RFID) is designed and simulated based on ISO/IEC18000-6 protocol UHF RFID protocols. The transmitter and receiver of RFID system are achieved and the backscatter technology is verified in multi-path fading and AWGN channel. The relationship between signal-to-noise and bit-error-ratio is given, which offers references to system application in scientific and reasonable design of RFID system.
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Computer Engineering. 2010, 36(17): 93-94,97. https://doi.org/10.3969/j.issn.1000-3428.2010.17.032
Using the status of water environmental pollution and monitoring management in Xi’an as its starting point, and combining with the low level of national monitoring and pollution increasingly serious problem, remote monitoring and intelligent system analyzing water quality of rivers and lakes is developed. The system consists of fixed-site remote monitoring sites, mobile wireless monitoring sites and biological monitoring sites, therefore, full-coverage and real-time water monitoring network is established. Experimental results show the system has functions of measurement data encrypted transmission, excessive alarm, real-time measurement data storage, scientific decision-making, and indicates the system has low power consumption, high reliability and easy installation ability and good practical significance.
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Computer Engineering. 2010, 36(17): 95-97. https://doi.org/10.3969/j.issn.1000-3428.2010.17.033
This paper presents an Internet of Things(IOT) application fundamental framework based on Service Oriented Architecture(SOA) in order to effectively integrate different enterprise services and decrease the loss of repeated work. The fundamental framework divides the SOA into six layers from original three layers, defines the functions of each layer, and gives two kinds of implemental technologies——.Net and Java platform. It uses radio frequency identification to build the IOT that solves whole process control problem, and uses a service-oriented architecture technology to achieve massive data sharing and efficient use of resources. The fundamental application framework is a feasible solution for enterprise resource integration.
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Computer Engineering. 2010, 36(17): 98-101,104. https://doi.org/10.3969/j.issn.1000-3428.2010.17.034
This paper introduces the recognition and orientation of objects in Internet of Things(IOT), analyzes Augmented Reality(AR) virtual interactive methods of IOT based on data glove, designs and realizes a virtual prototyping technology. Experimental results show the features of combining virtual and real objects, the natural experience provided to users, and the satisfaction of the application of IOT in the requirement of real time, precision and stability.
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Computer Engineering. 2010, 36(17): 102-104. https://doi.org/10.3969/j.issn.1000-3428.2010.17.035
Aiming at the specific traffic difficulty at the ramp corner, this paper proposes a traffic reminder system based on Wireless Sensor Network(WSN). The knowledge reduction of rough set theory is used to get the minimum set of reminder. It simplifies the design of the control circuit. It designs the intelligent control circuit using the state diagram based on the finite state automaton, which brings down the cost of hardware further. Experiment results indicate that knowledge reduction reduces the quantity of the remainders and the system states sets, and it reduces the cost of the hardware effectively, and increases the reaction velocity of the system.
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Computer Engineering. 2010, 36(17): 105-107,110. https://doi.org/10.3969/j.issn.1000-3428.2010.17.036Probe Gap Model(PGM) is a lightweight and fast available bandwidth estimation method, but the algorithms based on PGM are lack of systematic and in-depth assessment. This paper analyzes the main factors effecting the accuracy of PGM’s algorithms, proposes a new classification method of the end-to-end path available bandwidth, selects representative Spruce and IGI and evaluates the impact of the vital factors including cross traffic on the accuracy of algorithms systematically through theoretical derivation and simulation test. The research provides a reference to improve the design of algorithms and the accuracy of algorithms.
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Computer Engineering. 2010, 36(17): 108-110. https://doi.org/10.3969/j.issn.1000-3428.2010.17.037A lot of Wireless Sensor Network(WSN) MAC protocols use periodical sleep to save energy, gaining long lifetime. How to realize the communication between the nodes when using the periodical sleep mode is the focus research. An asynchronous MAC based on wake is a solution which achieves low energy consumption when applied to the sporadic traffic occasion. This paper improves the MAC protocol. The analysis and experiment shows that the modification reduces the energy consumption and improves the latency performance.
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Computer Engineering. 2010, 36(17): 111-113,116. https://doi.org/10.3969/j.issn.1000-3428.2010.17.038The performance of hash-based load balancing algorithm for network flow cannot be bounded under the worst-case because of hash conflicts. To make up for the shortage of the above algorithm, a multiple-hash algorithm based on counting bloom filter, which stores the digest of flow needed to be adjusted in the Exact Stream Bloom Filter(ESBF) structure, is designed. Compared with the basic hash table, the integrity of the conversation is maintained and the query performance is improved due to the lower probability of conflict.
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Computer Engineering. 2010, 36(17): 114-116. https://doi.org/10.3969/j.issn.1000-3428.2010.17.039The correlation among the Orthogonal Frequency Division Multiplexing(OFDM) subcarriers in the frequency domain is studied, and is used for subcarriers grouping. The number of coherent subcarriers is calculated according to the concept of coherent bandwidth, and is used to divide the subcarriers into groups. Average channel information within a group is proposed to represent the whole group. A simulation platform is established in Matlab to simulate the correlation among OFDM subcarriers in frequency domain. Simulation results show that it can greatly reduce the uplink feedback overhead, and do not result in the loss of system throughput performance when the group size is equal to the number of coherent subcarriers.
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Computer Engineering. 2010, 36(17): 117-119,122. https://doi.org/10.3969/j.issn.1000-3428.2010.17.040This paper presents a novel receiver windowing algorithm to combat the strong Narrowband Interference(NBI) in Ultra- Wideband(UWB) communication systems. The windowing is proposed for Multi-Band Orthogonal Frequency Division Multiplexing(MB-OFDM) UWB system which adopts the Zero Padding(ZP) scheme. Compared with other NBI cancellation algorithm, it has lower design complexity and need not NBI detection. Experiment of Packet Error Rate(PER) under different strong NBI sources verifies the effectiveness and feasibility of receiver windowing.
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Computer Engineering. 2010, 36(17): 120-122. https://doi.org/10.3969/j.issn.1000-3428.2010.17.041Due to the data scrambling in the transmitter, the conventional Integer carrier Frequency Offset(IFO) estimation method based on pilots correlation no longer works efficiently in China Mobile Multimedia Broadcasting(CMMB) system. In order to solve the problem, this paper proposes a new IFO estimation method for CMMB system. IFO is estimated with the synchronization signal which is a special part of CMMB frame structure. With the method, the influence on the carrier offset estimation caused by scrambling can be avoided. Simulation results show that even under multipath channel with low SNR and high Doppler frequency offset, the method still performs well.
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Computer Engineering. 2010, 36(17): 123-125,128. https://doi.org/10.3969/j.issn.1000-3428.2010.17.042A MAC algorithm——Frame-cum-Rate Adjustment(FRA) is proposed to contend for the wireless channel. In FRA, the value of CWmin is adjusted based on frame size acquired by lots of experiments and transmission rate. The wireless station with large frame size and high transmission rate can obtain high probability to access wireless channel. Simulation results show that compared with DCF, FRA increases the network throughput by 70% when different frame sizes and transmission rates coexist.
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Computer Engineering. 2010, 36(17): 126-128. https://doi.org/10.3969/j.issn.1000-3428.2010.17.043In present Wireless Sensor Network(WSN) MAC protocol research, it is generally assumed that node is static. This paper researches the influence of mobility on current WSN MAC protocols, and proposes Adaptive Synchronization Activation(ASA) algorithm. With the help of global time information, ASA avoids the influence that the mobility has to activation/sleep schedule mechanism in WSN MAC protocol. Simulation results show that ASA algorithm displays better performance in the mobile environment, and its packet delivery rate and energy efficiency is better than S-MAC protocol.
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Computer Engineering. 2010, 36(17): 129-131. https://doi.org/10.3969/j.issn.1000-3428.2010.17.044In the design of routing protocol for Wireless Multimedia Sensor Networks(WMSNs), aiming at how to meet QoS transmission requirements as well as to improve the energy efficiency at the same time, an efficient routing protocol called Cluster-based Real-time Routing Protocol(CBRP) is proposed. CBRP can effectively integrate the geographic forwarding mechanism with uneven virtual grid-based clustering routing protocol and dynamically adjust the data packets transmission rate. Simulation results show that CBRP meets the requirement of QoS in real-time and reliability domains and can prolong the network life cycle.
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Computer Engineering. 2010, 36(17): 132-134. https://doi.org/10.3969/j.issn.1000-3428.2010.17.045Energy-saving is a critical issue in wireless sensor network, since it is difficult to change or charge batteries in the existed Mobile Wireless Sensor Network(MWSN). In this paper, a novel mobile model is used to design a topology control algorithm with the help of relay region and GeRaF-like method. Theoretical analysis and simulations show that the proposed algorithm can save more energy, and it is an energy efficient topology control algorithm.
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Computer Engineering. 2010, 36(17): 138-140. https://doi.org/10.3969/j.issn.1000-3428.2010.17.047In network management, the Request-Reply(RR) model in Simple Network Management Protocol(SNMP) leads to the general disadvantages of overfull traffic, and sometimes-intolerable time lag. To overcome them, this paper proposes a Register-Distribute(RD) model, in which a concept of the object attributed table and its organizing style are given. To achieve it, the Management Information Base(MIB) is extended to constrain the behavior of every agent, and one distribution protocol is designed to support the novel RD model and resolve the compatibility between RR model and RD model. Experimental results show that the RD model decreases the traffic, and avoids the time lag effectively. Therefore, the proposed RD model can make the SNMP more efficient than the traditional RR model.
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Computer Engineering. 2010, 36(17): 141-143,146. https://doi.org/10.3969/j.issn.1000-3428.2010.17.048Aiming at the lack of the high false negative ratio of Least Recently Used(LRU) algorithm in high-speed network traffic measurement, this paper proposes a new algorithm which is based on the Multi-Granularity Least Recently Used(MGLRU). The algorithm employs hierarchical multi-granularity compression counting mechanism for high-speed network data sampling, and improves the accuracy of the long-term flow detection. And based on the real Internet data, simulation results show that: in the given conditions, the algorithm uses about 50 percent of the memory consumption and has 10 percent of relative error compared with the LRU algorithm.
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Computer Engineering. 2010, 36(17): 144-146. https://doi.org/10.3969/j.issn.1000-3428.2010.17.049In order to protect digital color image’s information, a color image encryption algorithm based on Lorenz chaos sequence and its decryption method protect from shearing attack are presented. 3D Lorenz chaotic sequences are improved to be with ideal pseudo-randomness. The RGB three-component combination image’s pixel positions are shifted and the pixel value is altered based on the 3D sequence so that the image will be scrambled and encrypted. While doing the decryption, a method is provided based on the neighboring pixels characteristic to renew the image attacked by shearing. The effects of encryption, decryption and security are also analyzed by using the method of accessing. Theoretical analysis and experimental results show that the algorithm has a large space of keys, a good encryption and decryption effects and efficiency, a better security performance to statistical analysis and strongly against shearing attacks ability.
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Computer Engineering. 2010, 36(17): 147-151. https://doi.org/10.3969/j.issn.1000-3428.2010.17.050In this paper, the main buffer overflow protection mechanism is summarized under the current Windows platform, and the method and technologies about bypassing these protection mechanisms are studied, which can increase the success rate of vulnerabilities analysis and use, and guide to improve the security of the operating system. The paper describes the development of the current main technologies on bypassing the buffer overflow protection mechanisms. The principles and methods about bypassing stack overflow protection, heap overflow protection Data Execution Prevention(DEP) are all given. Effectiveness of the methods of bypassing DEP is verified through an experiment.
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Computer Engineering. 2010, 36(17): 152-154. https://doi.org/10.3969/j.issn.1000-3428.2010.17.051A novel distributed intrusion prevention system model is presented and a use case scenario is given. The model uses interface-based modular ontology as knowledge base and context-depending policy as intrusion prevention method. As opposed to a monolithic approach, the modular ontology has advantages of good extensibility, high-efficient reasoning, etc. Moreover, ontology modules can be developed independently and configured flexibly through the notion of interfaces. By sending incident messages, ontology modules can update their knowledge more promptly and efficiently.
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Computer Engineering. 2010, 36(17): 155-157. https://doi.org/10.3969/j.issn.1000-3428.2010.17.052This paper analyzes a proxy multi-signature scheme and points out some problems in this scheme. The proxy signer can modify the proxy warrant if the delegation is not careful. The original signers can forge proxy signer’s signature. The original signers can forge a valid proxy multi-signature. Anyone can be framed.
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Computer Engineering. 2010, 36(17): 158-160. https://doi.org/10.3969/j.issn.1000-3428.2010.17.053In order to improve the security of bank network system, the tripartite network game model is presented which includes hackers, administrators and bank decisionmakers. Some basis are provided for strategy selecting of administrators and decisionmakers by analyzing the behaviors and interrelations between the three sides in the model. The sub-game model is adopted and analyzed to acquire the perfect Bayesian Nash equilibrium according to the characteristics of the tripartite model, and it makes the system administrator and the policy-making levels achieve the best strategy selection.
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Computer Engineering. 2010, 36(17): 161-163. https://doi.org/10.3969/j.issn.1000-3428.2010.17.054This paper discusses the security mechanism of the digital radio packet protocol MIL-STD 188-220C. Through the analysis of the principle of DAP-NAD algorithm, a non-interruption preferential M/G/1 model is extracted to analyze the security risks of DAP-NAD algorithm. Furthermore, an antagonism algorithm is proposed to verify the probability. A wireless network model composed of 12 nodes is set up in OPNET. All the nodes communicate according to the 220C, and DAP-NAD is chosen as the channel allocation algorithm. The antagonism algorithm is executed in the network model, and performances of network are compared. Related simulations are done to evaluate the performance of the protocol and verify the feasibility of the antagonism strategies.
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Computer Engineering. 2010, 36(17): 164-166. https://doi.org/10.3969/j.issn.1000-3428.2010.17.055For EPS-WLAN internetworking described in 3GPP Release 8, this paper analyzes security threats and attacks on EAP-AKA. In order to overcome vulnerabilities of EAP-AKA, it proposes an authentication and key agreement protocol based on EAP. The proposed protocol combines the elements of the IBE and IBAKA Scheme. Results of analysis show that the scheme can resist typical attacks and fulfill the security requirement without increasing complexity or system load.
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Computer Engineering. 2010, 36(17): 167-168,172. https://doi.org/10.3969/j.issn.1000-3428.2010.17.056In existing scheme, the dealer chooses and delivers secret information to every participant, so a secure channel between them is necessary, and in the recovery phase, the scheme can not check whether every participant provides the true information. Aiming at such shortcomings, the paper proposes a verifiable multi-secret sharing scheme based on ECC. Each participant’s secret shadow is selected and kept by the participant himself. The shadows do not need to be changed when the shared secret is renewed, and many secrets can be recovered one time. The scheme can check whether each participant provides the true information, so a secure channel between them is unnecessary.
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Computer Engineering. 2010, 36(17): 169-172. https://doi.org/10.3969/j.issn.1000-3428.2010.17.057Aiming at the security clustering problem in sensor network, a new trust evaluation scheme based on clustering is proposed in this paper. Based on the Gauss reputation model, each node chooses one node that has the highest value as its cluster head. It is proven in theory and in experiment that the improved arithmetic refines the distributions of cluster and cluster head, and this algorithm is more secure then other schemes for cluster based ad hoc networks, as well as in the suitability of network beginning.
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Network Intrusion Detection with Incremental Learning Algorithm Based on Hierarchies Decision TablesComputer Engineering. 2010, 36(17): 173-175,181. https://doi.org/10.3969/j.issn.1000-3428.2010.17.058Because there are rule update problems in network intrusion detection system whose rules are represented with rough decision table, this article presents representing the rules with hierarchies decision tables and making use of incremental learning algorithm to learn the new rules. Experimental results are carried out based on a set of benchmark DARPA data. It is observed that network intrusion detection system with hierarchies decision tables has a shorter training time, relatively low false negative rate and high accurate results for Probe and R2L&U2R attacks in comparison with that one only with rough decision table.
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Computer Engineering. 2010, 36(17): 176-178,181. https://doi.org/10.3969/j.issn.1000-3428.2010.17.059Aiming at the problems of authentication among roaming users, this paper proposes an Identity Based Encryption(IBE) wireless authentication protocol of anonymity roaming by using the IBE technology and the correlation characteristics of bilinear pairings. The security of authentication and anonymity are analyzed by formal approach under the unauthenticated-links model. It is showed that the protocol can achieve authentication securely, has a secure anonymity, and achieves the secure requirements of the wireless network. The protocol provides non-repudiation between different companies. Comparing with existing schemes, this protocol can be applied to the roaming authentication in the wireless network more practical.
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Computer Engineering. 2010, 36(17): 179-181. https://doi.org/10.3969/j.issn.1000-3428.2010.17.060Tree-based group key agreement protocol that allows group members to compute the group key based on their individual contributions can provide verifiable trust relationship between participants in Ad Hoc networks. The principles and structural features of three tree-based group key agreement protocols are discussed, and the communication and computation that generated by each protocol are compared when their members are adding in, leaving, merging or breaking up. The analysis and comparison results show that each tree-based group key agreement protocol is applicable to corresponding Ad Hoc networks. It also provides reference and technical support for application of more complicated tree structure in Ad Hoc networks.
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Computer Engineering. 2010, 36(17): 182-183,186. https://doi.org/10.3969/j.issn.1000-3428.2010.17.061In order to extract human contours from moving gait image sequences, this paper proposes a new division approach. It preliminarily extracts the area of the moving human-body by combining the background subtraction method and the symmetric frame difference method. Morphology algorithm is used to stuff the holes, banish the noise and shadow, and extract the mostly entire contours of human-body. The contours serve as the primary zero level set of improved C-V model to get the aim of gaining the accurate contours of human-body by handful iteration. The experiments in NLPR database show that the approach can extract the entire contours of moving human-body accurately, banish a lot of shadow and has good performances including noise robustness, low time complexity and high recognition rate.
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Computer Engineering. 2010, 36(17): 184-186. https://doi.org/10.3969/j.issn.1000-3428.2010.17.062This paper proposes a genetic algorithm for task scheduling in grid parallel computing. By designing a special coding method that one coding string contains two substrings, and each substring has different cross and variation methods. An evolutionary process of generalized genetic algorithm is adopted which makes the mother competes with the children also. Simulated experimental results show that the algorithm outperforms the algorithms using 2D coding or elite selecting strategy, it can gain better results and its convergent speed is faster.
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Computer Engineering. 2010, 36(17): 187-188,191. https://doi.org/10.3969/j.issn.1000-3428.2010.17.063To ensure the full load rate of delivering vehicle, this paper proposes a Sweep-Genetic Algorithm(S-GA). It starts to sweep with an arbitrary demand point which the demand is not zero as the starting point for sub path. Combining with the idea of saving algorithm, corresponding norm for inserting demand point is formulated. It follows the norm and inserts the demand point until all the demand points are in the route. As the arbitrary of starting point, it can form a number of possible solutions and obtain optimal solution by using Genetic Algorithm(GA). It uses the S-GA to solve the optimization problem of goods delivering of Zhengzhou coal electricity material supply and marketing limited company. Compared with the random S-GA, this S-GA can guarantee the full load rate of delivering vehicle and minimize the delivering cost.
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Computer Engineering. 2010, 36(17): 189-191. https://doi.org/10.3969/j.issn.1000-3428.2010.17.064In order to solve premature problem of genetic algorithm when assigning the fixed channel in cellular network, this paper proposes a self-adaptive genetic algorithm, which includes Max First Least Conflicts(MFLC) method to initialize the population, a novel incremental mutate operation and a new adaptive strategy to tune up the probability of mutation and crossover. Its performance is tested by a set of benchmark instances, and experimental result proves that the algorithm achieves better convergence rate with higher speed.
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Computer Engineering. 2010, 36(17): 192-194. https://doi.org/10.3969/j.issn.1000-3428.2010.17.065Aiming at the noise, moving background interruption and shadow in the complex background, a motion detection approach based on image block and edge enhancement is presented. Image block is used to model background. The obtained mask is repaired to become connected depending on its structural features. High level image-pyramid model is used to get object centroid and extract target. The Shift-Sobel operator is used to obtain thin edges, which are used to enhance the edges of mask twice so that the mask edges become compact. Experimental results show that the proposed approach can deal with shadow and complex background disturbance better than using the single Gaussian model and thus extract moving object effectively and accurately. Some drawbacks of frame-difference approach such as incomplete edge are overcome in the suggestion.
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Computer Engineering. 2010, 36(17): 195-197. https://doi.org/10.3969/j.issn.1000-3428.2010.17.066As for a class of hard 0/1 knapsack problem, this paper describes the combinatorial correlation between the maximum value and the items in the object set and proposes an algorithm named ZHKnap that applies the calculation of combined cross based on the greedy policy of the non-increasing profit-to-weight ratio. Experimental results show that ZHKnap outperforms state-of-the-art algorithm in polynomial time in terms of the average solution quality and prove that the optimum solution has no relation with both the coefficient of the items and the gap between the integer optimum and the linear optimum, instead, such solutions only relate to the combination of the items’ weight and the fraction derived with the greedy policy.
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Computer Engineering. 2010, 36(17): 198-200. https://doi.org/10.3969/j.issn.1000-3428.2010.17.067As lack of sufficient learning ability in traditional negotiation strategy of Agents, Agents’ techniques are still unable to meet the needs of modern E-commerce. Aiming at this problem, Q-reinforcement learning theory is adapted to improve the bilateral negotiation strategy of Agents and the corresponding negotiation algorithm is designed to achieve the negotiation strategies. Comparing with the negotiation strategy of time strategy, the proposed Agent negotiation strategy is better than time strategy in terms of negotiation time and algorithm efficiency. It shows that algorithm can strengthen online learning ability of E-commerce system, shorten the negotiation time, and improve the negotiation efficiency.
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Computer Engineering. 2010, 36(17): 201-203. https://doi.org/10.3969/j.issn.1000-3428.2010.17.068Aiming at the disadvantage of slow convergence and stagnation phenomenon of ant colony algorithm, path choice rule is introduced, which is based on contrast intensification technology, in order to increase the probability of selecting solution components, path choice rule strengthens the use of feedback and speeds up convergence speed. Information entropy is used to dynamic control to direction of contrast enhancement, which avoid stagnation of the algorithm and speed up convergence. An example is given, which is simulated by using basic Ant Colony Optimization(ACO) and improved ACO. Simulation results show that the improved ACO has excellent stability, performance of global optimization, and fast convergence.
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Computer Engineering. 2010, 36(17): 204-205,209. https://doi.org/10.3969/j.issn.1000-3428.2010.17.069To improve estimation precision for maneuvering target of Interacting Multiple Model(IMM) algorithm, more models are demanded while too many models tend to increase of computation and decrease of estimator performance. Aiming at the problem, this paper proposes a double Markov Model Set based Multiple Hypothesis IMM(MS-MHIMM) maneuvering target tracking algorithm. This algorithm uses Markov transfer matrix between model sets to describe large hops between model sets, adopts Markov transfer matrix of model to describe small hops or slow hops between models in the same model set. Modeling is refined and filtering precision is improved.
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Computer Engineering. 2010, 36(17): 206-209. https://doi.org/10.3969/j.issn.1000-3428.2010.17.070It is important to determine the kernel function and its parameters for Support Vector Machine(SVM). This paper proposes a fast method based on Gauss kernel function to get SVM parameter pair. According to the geometry between support vectors, parameter optimization is accomplished by using linear search method. The method is simple and easy to program. Experimental results show the method can solve the problem that Gauss kernel function is difficult to be determined in practical application and needs less time than existing methods.
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Computer Engineering. 2010, 36(17): 210-212. https://doi.org/10.3969/j.issn.1000-3428.2010.17.071This paper proposes a stereo matching algorithm combing wavelet transform and image segmentation. Multi-resolution phase acquired from Dual-Tree Complex Wavelet Transform(DTCWT) is used to get initial disparity map. For each scale, an equation is presented to measure the matching degree. Initial disparity map is amended into a high-resolution disparity map via color segmentation and disparity plane estimation. Experimental results show that the method is simple, and can achieve high accuracy and efficiency.
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Computer Engineering. 2010, 36(17): 213-215. https://doi.org/10.3969/j.issn.1000-3428.2010.17.072Popular hierarchical bounding boxes methods need split box continuously while getting the intersection of two models, therefore lower their efficiency. Aiming at the problem, by making use of its advantage that can exclude disjoint triangular patches quickly, this paper proposes a more efficient intersection method. It finds the intersection between two models directly to exclude a large number of disjoint triangular patches and gains the intersection lines of two models efficiently.
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Computer Engineering. 2010, 36(17): 216-217,220. https://doi.org/10.3969/j.issn.1000-3428.2010.17.073Aiming at the problem of one-to-many matching for multi-scale facet element, this paper presents multi-scale area entity shape matching based on tangent space method. It searches the candidate matching set by expanding the buffer zone outside the source polygon, combines the area patterns in the candidate matching assemble, matches the new polygon shape with the original polygon shape after combining the area patterns, and gets the best matching set. Experimental results show that computational process of the method is simple and easy to implement, and it has better matching efficiency.
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Computer Engineering. 2010, 36(17): 218-220. https://doi.org/10.3969/j.issn.1000-3428.2010.17.074Aiming at the problem of noise pollution in color image, this paper presents an improved adaptive switched vector filtering based on Peer Group Filtering(PGF). Using PGF detection noisy image to get the number of noise pixels which meet the test conditions in the filtering window, if the number of noise pixels which meet the test conditions is few, using directly vector median filtering for noise, if the number is large, using improved Adaptive Vector Median Filter(AVMF) to go on two time detection and decide filtering or not. Experimental results prove that the method has better performance on noise detection and protecting filtering details better.
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Computer Engineering. 2010, 36(17): 221-222,225. https://doi.org/10.3969/j.issn.1000-3428.2010.17.075Aimimg at the problem that range image is difficult to segment, this paper presents a range image segmentation method based on edge information fusion of normal components. Normal vector of every point in range image is computed, these normal vectors are decomposed into x component and y component which are used in building gray images. It uses Sobel operator in detecting edges of every range image and then these edges information are fused into an initial segmentation, and gets the final result by thin processing. Experimental results show that segmentation region edge closes completely and segmentation quality is above normal.
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Computer Engineering. 2010, 36(17): 223-225. https://doi.org/10.3969/j.issn.1000-3428.2010.17.076Aiming at the problem of motion estimation elapsed time for existing H.264/AVC encoder, this paper presents a fast motion estimation algorithm based on directional multi-template. This algorithm uses Sum of Absolute Difference(SAD) comparative method to search starting point, selects the appropriate non-symmetrical crisscross and hexagonal searching template which selects horizontal(vertical) by combining the relative movement intensity of the motion vector in horizontal(vertical) direction, gets the best match point, and outputs the optimal motion vector. Experimental results show that the computational speed of the encoder has increaseds 1.47 times than UMHexagonS algorithm in the case of the noise radio and the bit rate remaining practically unchanged, it can satisfy the requirement of the real-time for video coding.
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Computer Engineering. 2010, 36(17): 226-227,231. https://doi.org/10.3969/j.issn.1000-3428.2010.17.077In order to realize metamorphosis among series of polygons, this paper presents a non-linear 2D shape morphing method based on bivariate blending vector rational interpolation. It makes the vertex coordinate of series of polygons as vector on plane domain, builds rational interpolation surface by bivariate Newton-Thiele vector continued fraction, and series of metamorphosis polygons are generated by resembling the surface of this interpolation function. Experimental results show that this method has the high precision of calculation, strong adaptation and easiness of programming.
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Computer Engineering. 2010, 36(17): 228-231. https://doi.org/10.3969/j.issn.1000-3428.2010.17.078Aiming at the problems of data missing and occlusions in 3D reconstruction, this paper proposes a filling projective decomposition algorithm which can handle missing data. Sub-space and epipolar constraints are used to fit the measurement matrix and fill the missing data. The projective motion and structure are recovered by Singular Value Decomposition(SVD). To solve the problem that the method is sensitive to noise and exterior point, RANSAC algorithm and triangulation algorithm are employed to detect and correct the exterior point. Experimental results indicate that the algorithm can strengthen the robustness and reduce error for projective reconstruction through correcting the exterior point, and it has great application value.
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Computer Engineering. 2010, 36(17): 232-233,236. https://doi.org/10.3969/j.issn.1000-3428.2010.17.079This paper presents local region energy minimization model based on Markov Random Field(MRF) and probabilistic theory. The model converts traditional segmentation based on pixel into that based on region. It can reduce misclassification rate among the smooth area. The model is compared with the MRF model using ICM algorithm, Gibbs sampler algorithm and Metropolis sampler algorithm to segment image. Results show that the proposed energy model is able to obtain more accurate segmentation result and also can effectively restrain effect of image noise and texture for segmentation.
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Computer Engineering. 2010, 36(17): 234-236. https://doi.org/10.3969/j.issn.1000-3428.2010.17.080In order to improve the performance of the video watermark resist H.264 compression, this paper proposes a video watermarking algorithm based on Image Optical Flow(IOF). According to the optical flow rate of the points in video images, the total optical flow in the frame is calculated. The key video’s frames are selected on the basis of the dispersion of the total optical flow. And with the DCT block transform, the watermark information is embedded in those frames. Experimental results show that the algorithm can effectively antagonize the three compression modes of H.264 and ensure the robustness of the watermark and multiple requirements of the high image quality as well as the high compression ratio.
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Computer Engineering. 2010, 36(17): 237-239. https://doi.org/10.3969/j.issn.1000-3428.2010.17.081This paper proposes a novel video frame rate up-conversion algorithm based on improved bilateral motion compensation. Edge- weighted unidirectional motion estimation is applied to get bilateral motion vectors with high precision, and multi-stage motion vectors refinement is adopted to get more credible motion vectors. It apples the weighted index-based bilateral motion compensated interpolation to reduce artifacts. Experimental results show that the proposed algorithm provides better subjective and objective quality, when compared to the conventional algorithm.
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Computer Engineering. 2010, 36(17): 240-242. https://doi.org/10.3969/j.issn.1000-3428.2010.17.082To detect the voice change of speakers, an improved Bayesian Information Criterion(BIC) algorithm for speaker segmentation is proposed in this paper. The algorithm detects potential acoustic changes using fix-windows BIC algorithm, and validates the potential acoustic changes by two methods. One is the variable-size analysis window BIC algorithm, the other is based on the recursion of segmentation algorithm. Experimental result shows that the algorithm achieves better results, and compared with the BIC algorithm, the precision ratio, recall ratio and F-measure are improved.
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Computer Engineering. 2010, 36(17): 243-244,248. https://doi.org/10.3969/j.issn.1000-3428.2010.17.083The macroblock motion estimation process is a long time consuming part in H.264 standard. Aiming at this problem, a fast mode decision algorithm for motion vector prediction is presented in this paper for decreasing it efficiently. The average of predictive motion vector is computed according to the spatial correlation of video sequence, and the current block as a slow or fast motion block and the direction of motion vector are determined and an appropriate search pattern is selected according to the square mixed pattern. It is decided that whether the motion estimation terminated or not according to a given threshold. Experimental results show that the proposed algorithm can decrease 36.34% of average motion estimation time than the existing EPZS algorithm does with about the same quality of video coding.
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Computer Engineering. 2010, 36(17): 245-248. https://doi.org/10.3969/j.issn.1000-3428.2010.17.084This paper proposes a multimedia real-time sharing system in Peer-to-Peer(P2P) network based on a three-tier model. P2P network layer bases on JXTA protocol implements the resource search and issue. Service layer implements analysis of requesting information and searches media resource according to analytical result. Media application layer implements transmission and broadcast of audio and video streaming based on Java Media Framework(JMF), creates a copy of resource and publishes advertisement to the P2P network. This system uses catch along the matching points to speed up resource search. In order to avoid hot points, balance network load and select the optimum point dynamically, the paper proposes a concept of matching point service assessment parameter.
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Computer Engineering. 2010, 36(17): 249-251. https://doi.org/10.3969/j.issn.1000-3428.2010.17.085To solve different structure information sharing in construction supply chain, ontology integration based construction supply chain information sharing model and process model are designed, the platform framework is developed, and pivotal function module is expatiated. Significance of platform of how to support information sharing between enterprises in construction supply chain is given. Conclusion shows that construction supply chain information sharing platform based on ontology integration can support information research, professional knowledge learning and problem solving better.
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Computer Engineering. 2010, 36(17): 252-254. https://doi.org/10.3969/j.issn.1000-3428.2010.17.086OSEK/VDX Operating System(OS) specification is an international standard which is accepted by worldwide automotive electronics industry. To satisfy the reliability and real-time request of automotive electronics system, the timer mechanism of OS must handle the timer in a very effective way. This paper analyses the presentation of timer event in an embedded system, and proposes the approach which uses the ICTOH algorithm, heap sort algorithm and hardware counter to optimize the timer mechanism in OSEK Operating System. The comparison results show the proposed method is more effective than present methods.
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Computer Engineering. 2010, 36(17): 255-257. https://doi.org/10.3969/j.issn.1000-3428.2010.17.087This paper designs the remote monitoring system for industry boiler according to the features of industrial boiler safety monitoring and the requirements of remote centralized management. Digital average median filtering and limit amplitude filter are used for ensuring the accuracy of the data collection and stability of the system control. Through GPRS data interaction with remote server, client can access data through LAN and Internet. It uses C/S/S custom network data exchange protocol architecture to develop the network data access components, and realizes multi-point network monitoring function.
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Computer Engineering. 2010, 36(17): 258-259,263. https://doi.org/10.3969/j.issn.1000-3428.2010.17.088According to the USB communication need of ADSP-TS201 DSP, a whole USB communication system is designed, which includes hardware and software. A USB interface is extended by using CY7C68013A USB controller and FPGA. The USB software is designed based on VDK core. The message-function registration method and data buffer queue are used to enhance the performance. DSP can easily and efficiently communicate with host PC by invoking some function interfaces, and resource utilization rate is high.
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Computer Engineering. 2010, 36(17): 260-263. https://doi.org/10.3969/j.issn.1000-3428.2010.17.089This paper focuses on the design of Viterbi decoder for the Ultra-WideBand(UWB) wireless system. It improves the hybrid survivor path management unit in the decoder, promoting its maximum operating speed by 25% and reduces its decoding latency by 40 clocks. The implementation result on the Xilinx Virtex-5 XC5VLX330 FPGA shows the Viterbi decoder this paper presents can work correctly at 240 MHz. The data transmitted at all the eight kinds of speed can be decoded by using two slices of such Viterbi decoder in parallel.
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Computer Engineering. 2010, 36(17): 264-265,269. https://doi.org/10.3969/j.issn.1000-3428.2010.17.090Aiming at improving data throughput and system integration, this paper puts forward a method of 10 Gb/s optical fiber communication design based on XAUI interface protocol. It uses channel bonding technology of RocketIO transceiver to realize the data path between user logic and optical model. FPGA and XPAK optical module are used to simplify high-speed optical communication system design.
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Computer Engineering. 2010, 36(17): 266-269. https://doi.org/10.3969/j.issn.1000-3428.2010.17.091This paper proposes efficient hardware architecture of triangle setup engine with programmability on embedded platform, which is instead of using the dedicated hardware engine with complex functions. The triangle setup engine has 3-way SIMD arithmetic units, S15.16 fixed-point data path, eight pipeline stage with data bypass function and a high precision special function unit. The efficient architecture presented increases the processing speeding, as well as reduces the hardware cost. Experimental results show that the triangle setup engine has the ability to allow users to customize the rasterization algorithm. The triangle setup engine is implemented on Xilinx FPGA Vertex2P xc2vp30-7ff89 platform. The synthesized frequency reaches 78 MHz and the synthesized hardware resource is small with 3 354 slices, meeting the requirements of real rending on embedded platform.
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Computer Engineering. 2010, 36(17): 270-273. https://doi.org/10.3969/j.issn.1000-3428.2010.17.092In virtualized environment, the service capabilities on each domain are separated from each other due to isolation. In order to coordinate the service capabilities each domain may have, the inter-domain service process split mechanism under virtualization is introduced. Two kinds of service split methods are proposed. Based on Kernel Virtual Machine(KVM), two basic mechanisms are implemented for those methods: an inter-domain communication and a simple inter-domain Remote Procedure Call(RPC) mechanism. An application of text encrypting/decrypting across domains is presented, thus demonstrates that the model can be used to create new security-concerned application in virtualized environment.
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Computer Engineering. 2010, 36(17): 274-276. https://doi.org/10.3969/j.issn.1000-3428.2010.17.093In the radiation-hardened environment, registers are prone to SEU phenomenon because of energetic particle impaction, called register faulty. This paper proposes a method of register protection, dynamically requests the currently idle register to be the backup of the essential register as well as taking advantage of live migration technology during program progress to introduce protection for the essential registers, enabling registers themselves to have kind of fault-tolerant ability.
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Computer Engineering. 2010, 36(17): 277-279. https://doi.org/10.3969/j.issn.1000-3428.2010.17.094Collecting training data with positioning information is a costly work, which restricts the actual deployment of positioning estimation system and becomes a bottleneck problem. Aiming at the above problem, this paper presents a positioning estimation algorithm LocMR based on manifold regularization, which is a semi-supervised machine learning algorithm, to learn mapping function with a few labeled data and sufficient unlabeled data. The algorithm LocMR is verified in real IEEE 802.11 Wi-Fi wireless data set, result shows that it reaches higher accuracy, while reduces calibration effort greatly at the same time, thus the application availability of positioning estimation system is greatly enhanced.
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Computer Engineering. 2010, 36(17): 280-282,285. https://doi.org/10.3969/j.issn.1000-3428.2010.17.095A JTAG-based method and architecture of fast Flash programming are proposed. It downloads the controlling program of Flash programming before, and is self-identified and executed by the hardware. The JTAG interface is used only for the data transmission. It can effectively eliminate the JTAG bus transmission bottlenecks and increase download speed of Flash. Through downloading different programs of Flash programming, the Flash programming is made to be reconfigurable, supports different types of online Flash programming. The new architecture is more flexible but with little hardware overhead, and experimental result shows that the improved programming speed is about 17 times of that in the traditional method.
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Computer Engineering. 2010, 36(17): 283-285. https://doi.org/10.3969/j.issn.1000-3428.2010.17.096While analyzing the system performance, the state space of stochastic Petri nets increases exponentially with the enlarge of the system scale, which causes the complexity of system modeling. Stochastic Petri Nets in a Stochastic Petri Nets(SPN2) method is presented, in which Object-Oriented Petri Nets(OOPN) are adopted as formal theory bases. Compared with traditional methods, SPN2 method can be layered and object-oriented Nets-within-nets modeling system. As an example, it has a closer look at the reliability of communication needed for moving-block operation of high-speed train with SPN2 method.
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Computer Engineering. 2010, 36(17): 286-287,290. https://doi.org/10.3969/j.issn.1000-3428.2010.17.097Benchmark programs are widely used for selection evaluation of computer systems. Since the output data have different units, it is difficult to do further data processing. Another problem about benchmark programs is that the weighted sum scores do not have a theory basis. This paper proposes a PageRank-based computer performance evaluation method, the similarity between data serials are evaluated to produce the adjacency matrix. PageRank is then used on this matrix to produce PageRank score for each target function. Experimental result demonstrates the effectiveness and more objective of the method.
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Computer Engineering. 2010, 36(17): 288-290. https://doi.org/10.3969/j.issn.1000-3428.2010.17.098The distributed parallel Web Spider with center node is inadequate in expandability, and there is excessive burden on center node. In the same way, the communication load is not balanced. In order to overcome these problems, this paper presents an improved URL removing algorithm based on Rabin fingerprint algorithm. The improved scheme of Peer-to-Peer structure is proposed. The improved distributed parallel Web Spider is developed with ProActive middleware. Contrast experiments show that the improved Web Spider has higher collection efficiency, balanced communication load, without node bottleneck, and better expandability.
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Computer Engineering. 2010, 36(17): 291-封三. https://doi.org/10.3969/j.issn.1000-3428.2010.17.099To meet the demand of network target environment, this paper brings up a host model. The model sufficiently reflects the thumbprint and network characteristics of OS by simulating protocol stack fingerprint, process and file system. It can use the model to simulate server or client that own abundance of resource. Experimental result shows that the simulated hosts have thumbprint, and can be probed or scanned.
2024
Volume 50 No 4
Volume 50 No 4
(Started in 1975, Monthly)
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428