05 November 2010, Volume 36 Issue 21
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Computer Engineering. 2010, 36(21): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2010.21.001Aiming at the finesses of system in parallel, concurrency and resource sharing description, this paper introduces Colored Petri Net(CPN) into embedded Real Time Operating System(RTOS) modeling. It solves the realistic problem of CPU monopolization, the realization of task queue based on priority, the time dealing of task preempt, and the cycle of the tasks in RTOS task schedule model. A CPN model is built for preemptive priority task schedule example. Results show that this CPN model can relevantly describe the dynamic characters, and exactly simulate the efficiency and other performance of the RTOS.
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Computer Engineering. 2010, 36(21): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2010.21.002Aiming at the short-text classification in archive domain, this paper designs an automatic classification method based on concept network. It constructs domain ontology by analyzing the short-text language characteristic in domain, and converts the short-text of title to structural concept network which expresses through Resource Description Framework(RDF) by means of natural language processing technology. On that basis, it defines a similarity measure for archives to classify the retention period of archives. Experimental results show that this method gets a relative 24.2% decrease in classification error rate, and it improves the system performance compared with traditional short-text classification method based on characteristic selection.
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Computer Engineering. 2010, 36(21): 7-10. https://doi.org/10.3969/j.issn.1000-3428.2010.21.003Traditional XML database concurrency control protocols are almost based on the path locking model of XML document tree and it can not provide high concurrency. Aiming at this problem, this paper proposes an XML database concurrency control based on local path locking model. This protocol goes on node coding based XML, uses the scan function to judge the locking status of the target node ancestor and descendant, locks the target node or its parent node according to the operation type to reduce the frequent request for lock, improves concurrency for transaction and realizes the efficient management for large-scale XML data.
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Computer Engineering. 2010, 36(21): 11-13,16. https://doi.org/10.3969/j.issn.1000-3428.2010.21.004Based on the original binary systems integrity measurement model in trusted computing technology, this paper adds certificate authority and trusted property authority, designs new integrity measurement model of property remote attestation system, and proves credibility of the new model using predicate logic.Combining new features which are introduced in property remote attestation, this model converts binary fingerprints to property certificate using trusted property authority, as a basis of ensuring the previous model creditability, makes it have better applicability and feasibility.
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Computer Engineering. 2010, 36(21): 14-16. https://doi.org/10.3969/j.issn.1000-3428.2010.21.005Encoding method of adding forbidden symbol of Joint Source Channel Arithmetic Codes(JSCAC) is introduced. Error detection theory of JSCAC is demonstrated. Error detection delay distribution of JSCAC, geometric distribution is reviewed. Main decoding methods are analyzed and compared, sequential decoding method and its variants, decoding based on finite state machine and iterative decoding method based on JSCAC concatenated channel codes. Various problems in exiting decoding methods are pointed out. Problems of present researches on JSCAC are analyzed. The prospect of JSCAC is given.
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Computer Engineering. 2010, 36(21): 17-18,21. https://doi.org/10.3969/j.issn.1000-3428.2010.21.006Based on the implantation method of Basic Input Output System(BIOS) malicious code, this paper divides the malicious code into Industry Standard Architecture(ISA), Advanced Configuration and Power management Interface(ACPI) and Peripheral Component Interconnect (PCI) module malicious code, and analyzes the implementation processes of three types of BIOS malicious code. It designs a BIOS malicious code detection system which includes the modules of sampling, module disassembling, decompressing and malicious code analyzing. Application results show that this system can detect the malicious code in BIOS image file, and it can effectively enhance the security of BIOS.
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Computer Engineering. 2010, 36(21): 19-21. https://doi.org/10.3969/j.issn.1000-3428.2010.21.007Large numbers of short run-lengths embedded in precomputed test set limit compression efficiencies of some classical code schemes. Aiming at this problem, a test-bit-rearrangement algorithm is proposed. Some same electrical level bits are fasten on ends of test patterns by a greedy algorithm to decrease number of short run-lengths. Experimental results show that several code compression schemes can not only achieve higher compression ratios in combination with the test-bit-rearrangement algorithm than those in combination with the optimization difference, but also decrease test power dissipations.
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Computer Engineering. 2010, 36(21): 22-24. https://doi.org/10.3969/j.issn.1000-3428.2010.21.008Task schedule is a NP problem on grid research. In this paper, Niche Genetic Algorithm(NGA) is used to be the grid schedule algorithm combined with its advantages after anglicizing current schedule algorithms and introducing the method of arraying species with three principles. Experimental results with software GridSim show that NGA has better result, convergence rate and takes less resource than genetic algorithm.
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Computer Engineering. 2010, 36(21): 25-27. https://doi.org/10.3969/j.issn.1000-3428.2010.21.009In the distributed shared memory cluster system, this paper presents an OpenMP parallel computation method with explicit data distribution for nonlinear diffuse equation. The method partitions the whole data into small blocks, puts the block to the OpenMP thread and transfers data between the thread by using the copies in the shared memory. It designs a global reduction algorithm to reduce the synchronization times. Performance analysis and test results show that this method has well scalability on the distributed shared memory cluster with Intel Xeon quad-cores processors. Parallel speedup relative to 64 is 7.06 on 1 024 cores.
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Computer Engineering. 2010, 36(21): 28-30. https://doi.org/10.3969/j.issn.1000-3428.2010.21.010In order to solve the problems that XML document can not reflect the dynamic characteristics well, this paper adopts the method of modeling XML as temporal XML and proposes two mining algorithms based on temporal XML document named FCSBF and FCSDF to discover Frequently Changing Structure(FCS), which realizes efficiently mining frequently changing structures in dynamic XML documents. A novel clustering method for dynamic XML documents is presented. Experimental results show that the method is effective on clustering dynamic XML documents.
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Computer Engineering. 2010, 36(21): 31-33,36. https://doi.org/10.3969/j.issn.1000-3428.2010.21.011In order to analyze program control flow precisely and depict program control structure correctly, this paper introduces an overall architecture for control flow analysis and proposes an algorithm to generate the control flow of executable code. Key techniques such as abstraction of executable code and program control flow generation are described. Simple Assembly language Intermediate Representation(SAIR) is presented. Without changing semantics of the disassembly code, SAIR ensures thesimplicity and stringentness of analysis. The functions that create program control flow are defined based on SAIR and the algorithm that generates the control flow is proposed. The example of analyzing program control flow is given.
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Computer Engineering. 2010, 36(21): 34-36. https://doi.org/10.3969/j.issn.1000-3428.2010.21.012To effectively cope with data mining problem for high-dimensional outlier data, a novel outlier data mining algorithm based on Maximum Margin Criterion(MMC) and MiniMax Probability(MMP) machine is proposed. The high dimensional data sets are first projected into lower-dimensional feature space by using MMC algorithm, and MMP machine is adopted to mine outlier data. Experimental results show that the proposed algorithm is feasible and has higher detection accuracy.
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Computer Engineering. 2010, 36(21): 37-39. https://doi.org/10.3969/j.issn.1000-3428.2010.21.013In order to improve the efficiency of computing region inclusion relations, this paper proposes an algorithm for computing region inclusion relations based on QR-tree index. The algorithm builds a QR-tree index according to the information of spatial objects and queries all spatial objects including the region on the QR-tree. The algorithm is applied to spatial clustering in GML data based on line-region inclusion relations. Experimental results show that the algorithm is effective and efficient.
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Computer Engineering. 2010, 36(21): 40-42. https://doi.org/10.3969/j.issn.1000-3428.2010.21.014This paper presents an approach for metadata clustering based on maximal frequent path with a feature vector matrix. The metadata is depicted as a metadata tree. Then, maximal frequent sequences mining is conducted with the metadata tree according to the common features. In order to construct a feature vector matrix, it is necessary to weight the common features. The last step is to calculate the similarity between metadata trees for further clustering. Various examples in this study confirm that the presented approach can significantly improve the efficiency and effectiveness on metadata clustering by reducing the number of paths and endowing weights to paths.
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Computer Engineering. 2010, 36(21): 43-45. https://doi.org/10.3969/j.issn.1000-3428.2010.21.015In order to improve the quality of information retrieval systems, this paper proposes a complex and personalized model of query expansion. The proposed approach constructs a latent semantic space to get semantic concept related and interest related words. In this way, the model solves the famous vocabulary problem and meets various users’ needs. Experiments show this algorithm can significantly improve precision, recall and efficiency in information retrieval, meeting different users’ requirements in search engine systems.
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Computer Engineering. 2010, 36(21): 46-48,51. https://doi.org/10.3969/j.issn.1000-3428.2010.21.016Aiming at the difficulties and deficiency of ontology construction in user interest model and model updating, this paper presents an ontology-based approach to construct user interest model. The approach uses domain ontology, user personal ontology, correction ontology and ontology updating to achieve the model construction, it abandons the method of train, study and clusting to the construction of domain ontology , reguires category from ODP, updates user interest timely through correcting ontology construction, washing out users’ outdate interest and adjusting interest degree. Experimental results show that this model is easier to construct, and accuracy and timely of it is improved.
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Computer Engineering. 2010, 36(21): 49-51. https://doi.org/10.3969/j.issn.1000-3428.2010.21.017Load shedding is one of promising approaches when the system becomes overloaded because of irregular changes of the arrival rate of tuples. This paper proposes a data stream load shedding model called Delay-based Shedding Policy(DSP) which not only considers the processing capacity of system, but also the delay of processing data. The new policy based on delay-time is to fetch up the insufficiency of real time of existing load shedding policy. Experimental result shows that the DSP not only resolves overload efficiently, but also has high delay-time.
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Computer Engineering. 2010, 36(21): 52-53,56. https://doi.org/10.3969/j.issn.1000-3428.2010.21.018The demands of high speed synchronization of data in Air Traffic Control(ATC) system is increasing, while the speed of the traditional centralized databases that currently in use access for data can not meet the ATC system needs. Aiming at this problem, this paper designs and implements a main memory database based on type-index-value according to the special needs of ATC systems, the database has well portability, it can effectively improve the system performance and the access capabilities for data.
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Computer Engineering. 2010, 36(21): 54-56. https://doi.org/10.3969/j.issn.1000-3428.2010.21.019A similarity algorithm based on XML schema is brought forward. The similarity of XML Schema is an important foundation for XML clustering. Elements in XML are the main body and the similarity among elements is the major components of schemas similarity. The algorithm takes full account of the structure and semantics of elements. It can make more accurate calculation of similarity. In the mean while, it reduces the complexity and improves the accuracy of clustering. In addition, it is easy to extract the common XML schema of clustering by calculating the similarity among the XML schemas.
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Computer Engineering. 2010, 36(21): 57-58,61. https://doi.org/10.3969/j.issn.1000-3428.2010.21.020Existing researches on Web structure mining focus on finding the authoritative vertexes instead of the whole Web hyperlink structure. This paper designs the Website logical domain core and the model of domain core’s entry path, proposes logical domain core mining algorithm and its entry path mining algorithm. Through experiment on four large Websites, results show that both algorithms can achieve relatively high precision and recall.
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Computer Engineering. 2010, 36(21): 59-61. https://doi.org/10.3969/j.issn.1000-3428.2010.21.021The calculation method of the concept semantic similarity exists some problems in information retrieval, such as omitting retrieval false retrieval and omitting retrieval. Aiming at these problems, a semantic similarity model based on context is brought forward, which calculates the concept similarity of parent ones, child ones and the path weighted in the ontology. It calculates the sum of their weight, and obtains the semantic similarity. Experimental results show that the model results are closer to the experience of experts, and the values provide an effective quantification of the semantic relationship between the concept.
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Computer Engineering. 2010, 36(21): 62-64. https://doi.org/10.3969/j.issn.1000-3428.2010.21.022Large boundary region is one of the barriers for classical rough set theory applications. In this paper, drawbacks of the existing approaches for extended positive region from boundary region are discussed. Based on self-learning model under uncertain condition, a new approach for extended positive region is constructed. Algorithms of cognitive attribute core and attribute reduction are presented. Simulation results illustrate the efficiency of these algorithms.
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Computer Engineering. 2010, 36(21): 65-66,70. https://doi.org/10.3969/j.issn.1000-3428.2010.21.023This paper analyzes the current question parsing techniques in Question Answering(QA), and proposes a question feature exaction method based on syntactic structure and semantic information. The method parses question trunks based on syntax structure, then extracts characteristics of question from the semantic information point of view and uses modified Bayesian algorithm in question classification. Experiments show that this method can raise the accuracy of the question classification.
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Computer Engineering. 2010, 36(21): 67-70. https://doi.org/10.3969/j.issn.1000-3428.2010.21.024Rollback is one of the important functions of the workflow management system. The traditional methods of workflow rollback are single-step, stage by stage, prohibit cross-and-join and cross-and-split, which cannot meet the requirements of the changeability and complexity of the enterprise business processes. Based on the improvement of rollback rules and rollback algorithm, an application model is realized with re-development to the shark. Experiments show that the regenerated engine solves the problems of multi-step, ensures the data consistency and avoids the deadlock during the rollback.
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Computer Engineering. 2010, 36(21): 71-72,75. https://doi.org/10.3969/j.issn.1000-3428.2010.21.025OWL is a language that depicts semantics of ontology. It not only provides the strong semantic expression, but presents content that computer can be understandable. In the area of storage and managing megadata, the relevant techniques of relational database are matured. In this paper, the advantages of both are fully taken. It puts forward a storage model of relational database storing OWL ontology, which means that it can achieve a balance between storing megadata and maintaining the semantic integrity that renders relational database storing OWL ontology not only can store megadata, but also maximum maintain the semantic integrity.
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Computer Engineering. 2010, 36(21): 73-75. https://doi.org/10.3969/j.issn.1000-3428.2010.21.026Tree mining algorithm always produces a lot of problems such as frequent subtrees and tree database changing over time. This paper proposes least frequent closed tree mining algorithm and incremental updating algorithm for frequent subtrees. It proposes incremental strategy, makes full use of exists data, without re-running tree mining algorithm during update mining, and needs scaning database only once. It proposes tree pruning method, which can lessen the time of distinguishing isomorphism, and improve the efficiency of algorithm working. The final adoption of a large number of experiments shows that incremental updating algorithm proposed in this paper is effective and feasible.
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Computer Engineering. 2010, 36(21): 76-77,80. https://doi.org/10.3969/j.issn.1000-3428.2010.21.027This paper proposes a discernibility matrix of a formal context. By using the discernibility matrix, the characteristic functions of concepts and sub-concept lattices are defined. The judgement theorems for consistent sets in formal context and similarity concept in concept lattices are examined. At the same time, an approach for calculating all attribute reducts of concept and sub-concept lattices (including concept lattice) are formulated via the use of discernibility matrix and characteristic functions. A real example is used to demonstrate both its feasibility and effectiveness.
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Computer Engineering. 2010, 36(21): 78-80. https://doi.org/10.3969/j.issn.1000-3428.2010.21.028The query recommendation methods by mining search engines query logs can improve user satisfaction, such as the typical method based on TF-IQF model, however it does not take into account the context of user query behavior and can not meet the needs of individual users. In this paper, an improved query recommendation method based on TF-IQF model is proposed by analyzing user's query preference in the context of user queries and reordering the system recommended query. Experimental results show the improved query recommendation method gives personalized query suggestions and improves user query satisfaction further.
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Computer Engineering. 2010, 36(21): 81-82,85. https://doi.org/10.3969/j.issn.1000-3428.2010.21.029Based on Voronoi diagram and Delaunay triangulation and aiming at sample set of 2D closed curve set, this paper proposes a curves reconstruction algorithm. It samples the curve set according to sample dense to correctly reconstruct curve set with one or some lines. The measurement of dense extent is defined as local feature size of point, and samples are demanded to achieve a certain dense degree. Analysis proves that time complexity of the algorithm is O(nlogn).
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Computer Engineering. 2010, 36(21): 83-85. https://doi.org/10.3969/j.issn.1000-3428.2010.21.030This paper aims at the need of large scale and complex business processes of current software system, focuses on formalizing the logical description and disposal of business flow and logic. Mandarax, a Java rule engine, is introduced for consequence of the business rules. As a reusable system architecture integrates the main research achievement which builds the rule layer using Prova, implements the reasoning process of business logic. The rule-based software system architecture is proved to be feasible and effective, more complete in the theory level of software engineering design technique at some extent.
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Computer Engineering. 2010, 36(21): 86-88. https://doi.org/10.3969/j.issn.1000-3428.2010.21.031This paper presents a self-adaptive routing algorithm based on Bayesian estimation for Wireless Sensor Network(WSN), which solves the automatic adjustment of routing request zone. The algorithm sets the radius of cylindrical request zone as the parameter and makes use of Bayesian estimation to realize the self-adaptation of the routing request zone. The simulation results for packet delivery ratio, routing overhead, average packet delay, and residual energy ratio show this algorithm performes better than AODVjr.
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Computer Engineering. 2010, 36(21): 89-91,94. https://doi.org/10.3969/j.issn.1000-3428.2010.21.032This paper investigates the energy hole problem in WSN and proposes a new way to solve it. Based on coronas model, a statement of the dynamic longest-shortest coronas lifetime problem is presented and the mathematical model is constructed. It proposes an Immunity Clone(IC)-based energy-hole avoidance algorithm, which helps to prolong the lifetime of the network by searching for best coronas width and approximate optimal transmission range list. Simulation results show this algorthm balances the energy depletion and improves the network lifetime effectively.
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Computer Engineering. 2010, 36(21): 92-94. https://doi.org/10.3969/j.issn.1000-3428.2010.21.033To the question of different calculating methods between TFRC-RTO and TCP-RTO result in a great difference in throughput when they are competing, this paper presents an algorithm based on probability bias for TFRC-RTO. The algorithm zooms in or out the TFRC-RTO through subtracting the probability of actual packet loss events from the probability of optimal packet loss events to make it much closer to TCP-RTO. Simulation results indicate that, compared with the original algorithm, the new RTO algorithm enhances above 50% in throughput and the package loss number is reduced by half with short-RTTs.
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Computer Engineering. 2010, 36(21): 95-97. https://doi.org/10.3969/j.issn.1000-3428.2010.21.034This paper presents an optimum synchronization scheme aiming at the synchronization sensitivity of China Mobile Multimedia Broadcasting(CMMB). Utilizing the auto-correlation of preamble and scatter pilots, this scheme provides high-precision, low complexity symbol synchronization algorithm, frequency acquisition algorithms and frequency tracking algorithm. Simulation results indicate that proposed scheme performs robustly under TU6 channel with 300 Hz Doppler frequency shift at -2 dB SNR. Compared with the conventional scheme, the Root Mean Square Error(RMSE) of estimation is reduced by 50%.
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Computer Engineering. 2010, 36(21): 98-99,102. https://doi.org/10.3969/j.issn.1000-3428.2010.21.035802.11 standards provide a handover technique which meets requirements of application services without real-time requirements application, and it does not support the applications of video and audio in Internet. By studying handover for wireless network based on 802.11 technique, this paper introduces the definition, procedure and delay analysis of handover. Aiming at trigger phase and scan phase, it presents the real-time handover techniques such as smart trigger, neighbor graphs and SyncScan, and compares them with the current handover techniques in the terms of principle, algorithm and effect.
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Computer Engineering. 2010, 36(21): 100-102. https://doi.org/10.3969/j.issn.1000-3428.2010.21.036In order to broadcast Emergency Warning Messages(EWM) in Vehicle Ad hoc Network(VANET) fast and reliably, this paper proposes a broadcast mechanism based on rate adaptation for VANET named BRAVE combing the technology of multiple interfaces with multiple channels. Simulation results reveal that BRAVE can reduce the transmission latency and rebroadcast redundancy of EWM, and increase the transmission reliability to guarantee the message delivery. Compared with the mechanisms that select the broadcast nodes in terms of bit-rate and transmission range, its transmission latency is reduced by 3.9% and 66.0% respectively.
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Computer Engineering. 2010, 36(21): 103-105,108. https://doi.org/10.3969/j.issn.1000-3428.2010.21.037Aiming at the problem of the high complexities and port contentions of current routing switching mechanism, this paper proposes a dynamic re-routing switching mechanism based on Combined Input and Crosspoint Queuing(CICQ) switching fabric. It maintains multiple optional output port in forwarding layer according to the topology of the internet for each reachable destination, implements re-routing internal the switches according to congestion status to achieve real-time load balancing. Simulation results show that network switching system with this mechanism can provide good performance.
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Computer Engineering. 2010, 36(21): 106-108. https://doi.org/10.3969/j.issn.1000-3428.2010.21.038This paper proposes an Anti-Interference Channel Estimation(AICE) algorithm to solve channel estimation problem in MIMO-OFDM system. It decomposes the accumulated signal at receive end to obtain the signal of each transmitted antenna, and estimates channel by expectation maximization algorithm to reduce estimation error and improve accuracy by cancel Inter-Symbol Interference(ISI) and Inter-Carrier Interference(ICI). Compared with Iterative Channel Estimation(ICE) algorithm, AICE algorithm is proved that it can obtain better channel estimation performance in terms of mean square error and bit error rate in Rayleigh-fading channel.
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Computer Engineering. 2010, 36(21): 109-111. https://doi.org/10.3969/j.issn.1000-3428.2010.21.039This paper studies the delay of data services in wireless networks and presents a queueing model for performance analysis of Go-Back-N(GBN) Automatic Retransmission reQuest(ARQ) protocols in wireless networks using dynamic radio link adaptation with random feedback delay. Through the matrix-geometric methods, it calculates the probability distribution function of the delay at the sender side. It validates the correctness of the calculation method by simulation.
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Computer Engineering. 2010, 36(21): 112-114. https://doi.org/10.3969/j.issn.1000-3428.2010.21.040In wireless environment, TCP responds to all losses by invoking congestion control algorithm resulting in degraded end-to-end performance. Aiming at this problem, this paper proposes a method of wireless TCP based on bandwidth estimation and Explicit Congestion Notification(ECN). The data sender adopts available bandwidth estimation algorithm in order to optimize congestion window, and cooperates with the router which is configured with the function of explicit congestion notification to distinguish the characteristics of packet losses. The sender takes advantage of SACK option to speed up recovery of congestion window when multi-packets losses are occurred. Simulation results show that the throughput of modification of TCP outperforms TCP_SACK by 30%, and TCP_Reno by 52%.
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Computer Engineering. 2010, 36(21): 115-117. https://doi.org/10.3969/j.issn.1000-3428.2010.21.041Aiming at the global unicast address of WSN, this paper proposes a fast IP lookup scheme for IPv6 by using Bloom Filter(BF) as the storage structure by finding an appropriate storage method to reduce the false positive rate and longest prefix matching algorithm with a reasonable allocation of the prefix, so that it adopts a relatively small number of Static Random Access Memory(SRAM) to reduce the cost. Experimental results show that the method can reduce the hash probe of each routing, which can enhance the lookup speed of routing table and so improve the performance of WSN.
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Computer Engineering. 2010, 36(21): 118-120. https://doi.org/10.3969/j.issn.1000-3428.2010.21.042By studying dynamic adjustment algorithm of p-persistent CSMA protocol preliminary, this paper proposes an improved dynamic p-persistent CSMA protocol. In p-persistent CSMA protocol, the sending probability is fixed, while in dynamic protocol, the conflict probability of retransmission is a function of the conflict times of retransmission. The performance of normalized system saturation throughput is analyzed through building a two-dimensional Markov chain. Analysis results show that the protocol has better performance compared with p-persistent CSMA.
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Computer Engineering. 2010, 36(21): 121-122,125. https://doi.org/10.3969/j.issn.1000-3428.2010.21.043Due to the fact that the existing MAC layer of WiMAX system doesn’t provide specific schedule scheme for service with different priority, a modified DFPQ schedule algorithm is proposed. Based on the analysis of traditional hierarchical schedule algorithm, the modified schedule algorithm can solve the sudden with real-time service. In this algorithm, during allocation of bandwidth, allocating part of the bandwidth in low priority service to real-time service by determining the sudden incresement of real-time service. Using GloMoSim network simulation environment, simulation results show that the modified schedule strategy can meet the QoS requirements of various services and it’s superior to the traditional hierarchical schedule policy.
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Computer Engineering. 2010, 36(21): 123-125. https://doi.org/10.3969/j.issn.1000-3428.2010.21.044An iterative Maximum A Posteriori(MAP)channel estimation algorithm for Orthogonal Frequency Division Multiplexing(OFDM) system is proposed. The soft information from decoder is used by receiver. After interweaving the soft information, the receiver feeds them back to the channel estimator, in which the algorithm estimates the channel parameter. Through the iteration between the channel estimator and decoder, the useful soft information can be employed completely, which contributes to reduce the Bit Error Rate(BER), and improves the performance of the OFDM system.
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Computer Engineering. 2010, 36(21): 126-128. https://doi.org/10.3969/j.issn.1000-3428.2010.21.045This paper proposes a QoS schedule algorithm for bandwidth in NoC to solve traffic conflicts between different Guaranteed-Services (GS) connections which share the same physical link. By dynamically allocating priorities of these GS connections respectively, this algorithm can guarantee such QoS requirements as bandwidth, latency and zero jitter. It improves QoS and link efficiency of Best-Effort(BE) data flow significantly by allocating dynamic priorities to BE channels and monitoring GS traffic.
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Computer Engineering. 2010, 36(21): 129-131. https://doi.org/10.3969/j.issn.1000-3428.2010.21.046This paper proposes a reversible watermark algorithm with larger embedding capacity. Through a prediction way, it obtains an approximate value of the existing value, and embeds the watermark by using the differential value relation between the approximate value and the existing value. In extraction process, after extracting hided information, the original image is recovered. Based on the algorithms, another algorithm is proposed by adding information head, which has higher prediction accuracy. Experimental result shows that, compared with other reversible algorithms, the algorithms proposed have fewer modifications of the original maps with larger embedding capacity.
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Computer Engineering. 2010, 36(21): 132-133,136. https://doi.org/10.3969/j.issn.1000-3428.2010.21.047This paper demonstrates and analyzes the affect on steganalysis detection precision rate during image steganalysis detection process caused by feature dimensions, and contrasts the recognition rate of artificial selection with dimensionality reduction algorithm. Result shows that lower dimensionalities of the image feature vector not only make the classifier more effective and reduce the computational complexity, but also improve the image steganalysis detection rate, and the manifold learning algorithm is better than artificial selection in dimensionality reduction.
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Computer Engineering. 2010, 36(21): 134-136. https://doi.org/10.3969/j.issn.1000-3428.2010.21.048This paper proves that the success rate of differential attack on self-synchronous HBB by Joux method is 0.31. It analyzes the relationship between the data complexity and success rate for obtaining the key and gives an improved method to the differential attack. By deriving differential distribution of SPS in HBB algorithm, the success rate is improved to 0.6, and the data complexity is decreased from 2 KB to 1.3 KB.
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Computer Engineering. 2010, 36(21): 137-139. https://doi.org/10.3969/j.issn.1000-3428.2010.21.049This paper presents an improved transduction network anomaly detection algorithm, it applies K-L transform for dimension reduction to high-dimensional data which is used for Euclidean distance calculation, and adopts branch and bound tree for reducing times of Euclidean distance calculation. Experiment based on KDD CUP99 dataset demonstrates improved algorithm can improve real-time performance of network anomaly detection. In comparison with anomaly detection algorithm based on OC-SVM, improved algorithm can obtain a better detection rate while keeping a proper false positive rate.
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Computer Engineering. 2010, 36(21): 140-142. https://doi.org/10.3969/j.issn.1000-3428.2010.21.050In order to improve the performance against attack of watermark algorithm, this paper presents a robust watermark algorithm based on Singular Value Decomposition(SVD) and geometrical correction. Watermark bits are embedded in first singular value of each block through quantization, the optimization of quantization step is acquired by genetic algorithm. While extracting watermark, Directe Fouriet Transformer(DFT) and geometrical invariant moment are introduced to estimate geometrical transform and rectify test image. Experimental results show the algorithm is robust to resist normal and geometrical attack.
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Computer Engineering. 2010, 36(21): 143-145. https://doi.org/10.3969/j.issn.1000-3428.2010.21.051There exists the dynamic assignment problem between roles and access permissions in the process of collaborative design, which is caused by the dynamics of task execution. On account of this problem, it introduces task association in collaborative design access control, proposes a dynamic access control model based on task and role——TRBAC, and gives formal description of it. It discusses the collaborative design access control and designs the authorization and control algorithm. It takes the CAM group collaborative design for example, through the introduction of TRBAC to achieve the dynamic access control.
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Computer Engineering. 2010, 36(21): 146-148,151. https://doi.org/10.3969/j.issn.1000-3428.2010.21.052Existing Peer-to-Peer storage network can not guarantee confidentiality and security of the clients’ files on the distrusted nodes, and only uses the low efficiency way of redundancy copies to ensure the availability of their documents. Aiming at this problem, this paper proposes a new kind of architecture of peer-to-peer storage network which can meet different clients’ needs. It proposes the system according to the defects of the existing Peer-to-Peer storage network system. Results of analysis shows that the system can meet the different needs of occasions, and ensure the survivability of storage networks effectively.
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Computer Engineering. 2010, 36(21): 149-151. https://doi.org/10.3969/j.issn.1000-3428.2010.21.053The ideas of group re-keying algorithms based on secret sharing using the LKH tree are proposed in this paper. The algorithms construct a message using secret sharing with the dynamic change of group members. The group members can reconstruct the new group key. It is proved that the new algorithms have obvious superiority than that of the previously proposed algorithms on communication and computation, and are suitable for large dynamic group.
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Computer Engineering. 2010, 36(21): 152-153,156. https://doi.org/10.3969/j.issn.1000-3428.2010.21.054A semi-fragile watermark algorithm based on mean computation and coefficient classification is proposed. It divides the original image into blocks, and carries through mean computation on each block. The decimals of those coefficients derived from mean computation follow certain rule. The rule is used to classify those coefficients into two groups. It makes the high four bits of every pixel right shift, and derives zero-watermark sequence by comparing the quantities of coefficients in the two groups. The inconsistency between the quantities of coefficients in every group resulted from tamper is used to test its ability to tamper location. Experimental result shows that the algorithm has good transparency and enough robustness to resist the common image processing operations. It is able to locate the tampered areas and it has low probability of miss. It is able to resist collage attack.
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Computer Engineering. 2010, 36(21): 154-156. https://doi.org/10.3969/j.issn.1000-3428.2010.21.055Due to complicated network environment, the traditional worm propagation model can not be adequate to describe the late phase of passive P2P worms propagation. The major characteristics of the late phase of passive P2P worms propagation are discovered by modeling worm propagation and analyzing simulation experiments. The results show that the propagation of passive P2P worms has some close relationships with both the number of P2P nodes which do not patch security holes and the probability to patch security holes in time. Passive P2P worms can spread continuously in the network environment of lower security consciousness.
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Computer Engineering. 2010, 36(21): 157-158,161. https://doi.org/10.3969/j.issn.1000-3428.2010.21.056The original scheme can’t achieve mutual authentication between client and AP. Aiming at this problem, this paper analyses one classic threshold authentication scheme for Wireless Mesh Network(WMN) in which the client has to excute asymmetrical encryption causing less efficient. It proposes one compromise-resilient threshold authentication scheme. It adopts improved ECDSA signature, threshold signature. Result shows the clients in this scheme do less operation. It achieves mutual authentication between client, AP and AS. It prevents the server-compromise effectively.
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Computer Engineering. 2010, 36(21): 159-161. https://doi.org/10.3969/j.issn.1000-3428.2010.21.057This paper proposes a quantization evaluation algorithm for attack graph based on node score named NSBRank, which is used to quantize the importance of all nodes in the attack graphs. It computes the initial ranks of all nodes, and works out the final ranks on the basis of the initial values, so that the relative importance between nodes is more clear, and the ability of response for network security is enhanced. Experimental results prove that NSBRank is more reasonable and effective.
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Computer Engineering. 2010, 36(21): 162-163,166. https://doi.org/10.3969/j.issn.1000-3428.2010.21.058Aiming at the calculating problems of very large Fibonacci numbers and Lucas numbers, an associated iterative algorithm for Fibonacci numbers and Lucas numbers is proposed, which selects double step in a single cycle and uses the method of alternate calculating of Fibonacci numbers and Lucas numbers. The algorithm reduces complexity of iterative formula of very large numbers and improves the computational efficiency of program. Experimental result shows that running time of the algorithm is faster than the matrix iterative algorithm.
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Computer Engineering. 2010, 36(21): 164-166. https://doi.org/10.3969/j.issn.1000-3428.2010.21.059Aiming at the problem that existing steganalysis algorithm has poor detection performance, this paper presents a universal steganalysis algorithm based on multi-wavelet statistics feature. Image is decomposed to multi-scale and multi-direction through multi-wavelet transform. Then two kinds of statistics features are got through every sub-image. The Support Vector Machine(SVM) is trained on these statistic features to construct a universal steganalysis. Results show that this algorithm can catch more effective features of image and it has correct detection rate compared with Farid algorithm.
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Computer Engineering. 2010, 36(21): 167-169. https://doi.org/10.3969/j.issn.1000-3428.2010.21.060Aiming at actions of virtual battlefield individual with the intelligence and autonomy characteristic, internal factors that influence personnel external behavior are broken down into meta-Agents with considering behavior functions, and a battlefield individual behavioral model is advanced by aggregating meta-Agents. Meta-Agent structure is accomplished by intelligent model based on its main features, with describing values and reliability of perception factors, evaluating the vision of intention by revenue target, carrying out repeat battlefield action preferential through the probability of actions performed. Compared with traditional methods, the meta-Agents aggregation behavioral model greatly improves the intelligence, autonomy and diversity of behavior by handling the coupling and complex interactions of meta-Agents, which provides a new approach to battlefield individual action modeling.
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Computer Engineering. 2010, 36(21): 170-172. https://doi.org/10.3969/j.issn.1000-3428.2010.21.061A gait recognition algorithm based on the Choquet fuzzy integral feature fusion is proposed, using the features of wavelet moment and the width of the binary human silhouette images. For each image sequence, a background subtraction algorithm is used to segment and track the moving silhouettes of a walking figure from the background. It is attempted to describe the gait contour by using the wavelet moment and the width, the support vector machine is used to apply as the first classification to wavelet movement features and the width feature. The Choquet fuzzy integral is used to apply as the multi-feature fusion classification to the first result, based on its importance of the features. Compared to the recent research results, experiment results show the Choquet integral fusion method is better than the general linear weighted fusion method.
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Computer Engineering. 2010, 36(21): 173-174,177. https://doi.org/10.3969/j.issn.1000-3428.2010.21.062The structure metrics such as Root Mean Square Deviation(RMSD), TM-score, and GDT-TS etc. reflect only distance instead of energies difference between any decoys. This paper calculates difference of energies for any pair of decoys, modifies the similarity matrix with the differences, and clusters decoys with these similarity matrices respectively. Experimental results on 13 decoys sets show that the strategies of weighting similarity based on energies for clustering protein structures can improve the performance of clustering.
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Computer Engineering. 2010, 36(21): 175-177. https://doi.org/10.3969/j.issn.1000-3428.2010.21.063This paper proposes two methods based on sparse representation to deal with face recognition with one training image per person. In the proposed two methods, it generates the multiple images by shifting the original image or reconstructing the original image using Principle Component Analysis(PCA) method, and regards new images as training samples, and then applies Sparse Representation-based Classification(SRC) on new training samples set. Experiments on the well-known ORL database show that the proposed two methods are about 5.56% and 1.67%, more accurate than original SRC method when considering in the context of single sample face recognition problem. In addition, extensive experimentation reported in the paper suggests that the proposed two methods achieve lower error recognition rate than Shifted images +PCA, Shifted images +LDA, PCA reconstructed images +LDA, PCA, LDA.
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Computer Engineering. 2010, 36(21): 178-180. https://doi.org/10.3969/j.issn.1000-3428.2010.21.064Geometric feature extraction from image is a crucial step in image classification and recognition algorithms. It requires to calculate the Minimum Enclosing Rectangle(MER) of the image to get some attributes, such as length and width. This paper proposes an algorithm based on the combination of the vertex chain code and the discrete Green theorem to extract MER from image. According to this algorithm, it can calculate the area, centroid, and principal axis of the image easily, only with its point coordinates from the veritical or hrizontal direction of the vertex chain code. Experimental results show that the rotation method’s speed is two times of the current algorithms, while the principal axis method is three times of the rotation method.
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Computer Engineering. 2010, 36(21): 181-184,187. https://doi.org/10.3969/j.issn.1000-3428.2010.21.065This paper proposes object recognition methods for images with simple imaging conditions and challenging imaging conditions, which are based on Class Specific Hyper Graph(CSHG) model. In the process of recognition for images with simple imaging conditions, it extracts their robust Scale Invariant Feature Transform(SIFT) features and describe them using graphs. The objects in test images are recognized efficiently by using a RSOM clustering tree and K-nearest neighbor method. In the process of recognition for images with challenging imaging conditions, the approximate interest object regions in test image are located by sliding window method. The approximate object regions are expanded or shrunk iteratively and their corresponding graphs matche to graphs in CSHG model. The exact object regions are located by checking the number of matching features and segmented from test images. K-nearest neighbor graphs of the object regions are obtained in CSHG model and final recognition decision are made by using a majority voting strategy. Experimental results demonstrate that the methods are effective.
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Computer Engineering. 2010, 36(21): 185-187. https://doi.org/10.3969/j.issn.1000-3428.2010.21.066Aiming at problems of large scale spare parts and cloth optimizing, this paper analyzes the application of improved generic algorithm in the irregular graph stock layout, and researches the advantage and disadvantage of generic algorithm in the intelligent optimizing stock layout. Based on conventional generic algorithm, it puts forward an improved algorithm which classifies graph group by their similarity degree in order to simplify time complicity of generic algorithm. Experimental results prove that this means outgoes the conventional one in time complicity, so it is applied to large scale of graph stock layout system.
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Computer Engineering. 2010, 36(21): 188-190,193. https://doi.org/10.3969/j.issn.1000-3428.2010.21.067Geography Information System(GIS) is introduced into Intelligent Decision Support System(IDSS) and a 4 base and 1 machine frame model is proposed. On this basis, Target Assignment Intelligent Decision Support System(TAIDSS) is designed, it realizes the integration of IDSS, GIS and decision-making model, then an intelligent target assignment decision model which contains knowledge base subsystem is proposed. reasoning machine principle is adopted to carry out expression and treatment of expert knowledge. Simulation shows the model has short computing time and reasonable result, can satisfy dynamic battlefield environment and real-time demand.
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Computer Engineering. 2010, 36(21): 191-193. https://doi.org/10.3969/j.issn.1000-3428.2010.21.068This paper designs a testbed for the application in multiple intelligent robots collaboratively completing a real-time regional monitoring. Positioning algorithm, communication model and control tasks are designed based on hardware platform of three robot vehicles. The application plan is achieved with C# programming language. The main consideration is to keep vehicles formation in the region to ensure the integrity of patrol coverage, the characteristics setting of the invasion target and the behavior strategies after finding target. The construction of the experimental system provides an experimental test platform for theoretical study of the multi-Agent system.
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Computer Engineering. 2010, 36(21): 194-195,198. https://doi.org/10.3969/j.issn.1000-3428.2010.21.069According to the needs of automatic transport, a visual navigation wheeled-mobile robot based on FPGA+ARM is designed. Images are acquired, saved and displayed by FPGA. The path recognition, communication, executive units and sensors are controlled by ARM. To recognize path, binary image is built, the guide line is detected and the navigational parameters are carried out by path tracking module. Experimental results show the reliability of the robot which can track the expected navigational path exactly.
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Computer Engineering. 2010, 36(21): 196-198. https://doi.org/10.3969/j.issn.1000-3428.2010.21.070This paper proposes a detection algorithm of moving object based on self-adaptive threshold configuration, unlike previous approaches to object detection which detect objects by global threshold, it uses a local threshold to reflect temporal persistence which combines global threshold and local thresholds. The proposed approach can handle scenes containing gradual illumination variations and noise and has not bootstrapping limitations. Experimental results on different types of videos show the utility and performance of the proposed approach.
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Computer Engineering. 2010, 36(21): 199-201. https://doi.org/10.3969/j.issn.1000-3428.2010.21.071Aiming at the problem of the universal space partition in the process of constructing rough set neural network, this paper proposes an universe of discourse method based on fuzzy clustering. A modified PSO algorithm with crossover and mutation operators is combined with FCM algorithm. And a new fuzzy clustering algorithm(CMPSO-FCM) is proposed. The searching capability and clustering effectiveness are improved by the new algorithm. A set of fuzzy rough decision rules are acquired by entropy method, and a rough set neural network is designed under these decision rules. Experimental results show that this method has superiorities at the aspect of structure, classification precision and generalization.
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Computer Engineering. 2010, 36(21): 202-203,206. https://doi.org/10.3969/j.issn.1000-3428.2010.21.072This paper proposes a new vehicle taillights detection algorithm for the night view rear-end collision alarm system of smart vehicle. The algorithm combines with routine geometry parameters, makes use of four thresholds of brightness and color to detect vehicle taillights. The TB_L is used to locate the suspected taillights facular areas, the routine geometry parameters are employed to check and eliminate the suspected taillights facular areas, the TRP_L and TBP are adopted to determine the facular areas of bright taillights, the TRP_H is used to determine the facular areas of dim taillights. Experimental results show that the algorithm can detect taillights accurately and quickly.
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Computer Engineering. 2010, 36(21): 204-206. https://doi.org/10.3969/j.issn.1000-3428.2010.21.073Most Active Queue Management(AQM) algorithms based on control theory have low robustness and queue stability under the complex network environment with uncertainties since those algorithms are more sensitive to the variations of network parameters. Aiming at the above problem, this paper presents a novel fuzzy AQM algorithm based on the relative changes of queue length and link rate, which introduces two relative errors as congestion notifications and also as the inputs of fuzzy inference system, one is the error between current queue length and the desired values, the other is the error between the link rate and link capacity, an appropriate dropping probability at router is determined by a set of fuzzy rules. Simulation results show that the algorithm has better performance on queue stability and less delay, at the same time it has good robustness for nonlinearity and load variation.
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Computer Engineering. 2010, 36(21): 207-208,211. https://doi.org/10.3969/j.issn.1000-3428.2010.21.074In order to improve the recognition performance of neighborhood preserving embedding, this paper proposes a face recognition algorithm based on modified neighborhood preserving embedding LDNPE. Using the priori classification information, the weight value matrix of original Neighborhood Preserving Embedding(NPE) is modified. Subsequently, the objective function of NPE is also changed by combining the between-class scatter matrix. Based on the modified NPE, the transformation matrix can be obtained. As a result, the features of training samples and testing sample are got by projecting them on the subspace spanned by optimal base vectors. Nearest Neighborhood(NN) algorithm is used to construct classifiers. Several experiments are conducted on CAS-PEAL and FERET face database. Results demonstrate the effectiveness of the proposed method.
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Computer Engineering. 2010, 36(21): 209-211. https://doi.org/10.3969/j.issn.1000-3428.2010.21.075Nowadays, intelligence vehicle has the capability of computing, communication and storage to get the real-time traffic information. This paper constructs a real-time traffic network by using the real-time GPS data. Real-time information is designed based on path planning strategy and the performance is evaluated compared to four kinds of well-known strategies. And a significant improvement by 33% can be taken by intelligence vehicle when using real-time traffic information.
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Computer Engineering. 2010, 36(21): 212-213,216. https://doi.org/10.3969/j.issn.1000-3428.2010.21.076Aiming at the camera calibration in vision navigation system of mobile robot, this paper proposes an efficient method of camera calibration. The radial distortion and tangential distortion is taken into account. Hough transform is applied to extract the checkboard corners, and initial values of camera parameters are obtained. Levenberg Marquardt algorithm is used for nonlinear iteration optimization. The corners are reprojected to the rectangular checkboard, the corners extracted are compared with Hough transform, and the causes of error are analyzed. The results show that this method of anti-noise ability is strong, and the experimental conditions are relatively low. The precision completely satisfies requirement of actual navigation, which is suitable for camera calibration of mobile robot.
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Computer Engineering. 2010, 36(21): 214-216. https://doi.org/10.3969/j.issn.1000-3428.2010.21.077This paper proposes a new algorithm DTML(Determination Threshold for Multi-label Learning). An optimal threshold is set for each label by learning from the training data set. When the score for a test instance to one label is bigger than threshold which is set for the label, the label will be added to the last classifying result for the test instance. This method is implemented and applied to PT5 method and TML algorithm. Experimental results show that the DTML method can get a well performance on learning threshold for multi-label algorithms.
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Computer Engineering. 2010, 36(21): 217-219. https://doi.org/10.3969/j.issn.1000-3428.2010.21.078Deterministic parsing has the greedy characteristic that easily brings the error propagation. Aiming at this question, this paper proposes a deterministic dependency analysis algorithm for Chinese including three steps. It utilizes SVM to construct a root finder to divide a sentence into two sub-sentences and extracts the prepositional phrases from sub-sentence. Improved Nivre’s algorithm is adopted to parse sub-sentence. It does pre-processing before parsing sentences to decrease the complexity of the sentence and reduce the error propagation, and improve the parsing accuracy consequently. Experimental evaluation shows the accuracy of this parsing strategy is higher by 3.38% than Nivre’s.
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Computer Engineering. 2010, 36(21): 220-221,224. https://doi.org/10.3969/j.issn.1000-3428.2010.21.079One of the most important targets in the radio networks planning based on TD-SCDMA standard is obtaining a satisfying networks quality. On the basis of Genetic Algorithm(GA), an improved GA is proposed based on PCCPCH RSCP coverage and PCCPCH C/I coverage. It uses binary matrix coding which meets network multi-cell and multi-parameter. For getting a rapid convergence, a special crossover method named patch-crossover is posted. Scaling function is applied to the fitness function to avoid local convergence. Experimental result shows the outstanding performance of this optimization algorithm, the PCCPCH RSCP coverage ratio and PCCPCH C/I coverage ratio increase in different degree.
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Computer Engineering. 2010, 36(21): 222-224. https://doi.org/10.3969/j.issn.1000-3428.2010.21.080Considering single type of chaotic map and not deeply study of effect size and mechanism of chaotic map on the algorithm performance at present, this paper analyzes and dicusses performance of Chaos Immune Evolutionary Algorithm(CIEA) based on different chaotic maps. Four benchmark functions are employed to test performances of the three chaos immune evolutionary algorithms. Comparison results demonstrate that the performances of Logistic-CIEA and Cubic-CIEA are easy to cause large fluctuation. However, Kent-CIEA has relatively steady convergence rate and shows strong robustness. It proves that the performance of chaos immune evolutionary algorithm is deeply affected by the characteristic of chaotic map, which is applied to generate the local search trajectory.
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Computer Engineering. 2010, 36(21): 225-227. https://doi.org/10.3969/j.issn.1000-3428.2010.21.081The Pulse Coupled Neural Network(PCNN) is a new artificial neural networks model, and several PCNN structures for image segmentation are proposed depending on the model’s potential. But it isn’t a trivial task to define the relative parameters properly in the research of the theories and the applications of PCNN. As a contribution to this research field, this paper presents a new method for image segmentation based on differential evolution algorithm. Differential evolution algorithm as a new evolutionary algorithm can accomplish the automatic search of target parameter with its superior characteristic. Application of key parameters’ automatic setting in image segmentation, and the comparison between this segmentation result and other segmentation methods, the correctness and advancement of this case are verified.
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Computer Engineering. 2010, 36(21): 228-230,233. https://doi.org/10.3969/j.issn.1000-3428.2010.21.082Based on the analysis of inertia weight and the maximal flying speed , the improved Particle Swarm Optimization with Contracted range of search Velocity(CV-PSO) is proposed for the adaptive image enhancement. It combines with incomplete Beta operator which containes all different kinds of typical transformation functions. The algorithm is used for the basic and traffic images enhancement. It compares its performance with that of basic Particle Swarm Optimization(PSO) and other improved PSO. Results show that CV-PSO is effective and superior. Moreover, it is better than traditional histogram equalization method in visual quality.
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Computer Engineering. 2010, 36(21): 231-233. https://doi.org/10.3969/j.issn.1000-3428.2010.21.083Vocabulary tree-based method is one of the most effective image retrieval methods. However, for existing Vocabulary tree methods, the retrieval precision in large scale image database is not acceptable especially for image datasets with high variations. This paper proposes a novel tree fusion framework Feature forest, utilizing and dynamically fusing different kind of local visual descriptors to achieve a better retrieval performance. Experimental results show the effectiveness of the approach compared with single Vocabulary tree-based methods on different databases.
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Computer Engineering. 2010, 36(21): 234-235,238. https://doi.org/10.3969/j.issn.1000-3428.2010.21.084By analyzing traditional paper cut picture, this paper decomposes them into different decorative patterns , which are divided into independent patterns and complex patterns. It constructs a colorful independent pattern bank through boolean operating to bi-level graphics, and constructs complex pattern bank using the technologies of extended symmetry and gradient based on the independent pattern bank. The paper simulates folded paper-cut effect so as to generate diverse forms of folded paper-cut patterns according to actual needs.
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Computer Engineering. 2010, 36(21): 236-238. https://doi.org/10.3969/j.issn.1000-3428.2010.21.085Based on the property of SAR image speckle noise and Contourlet property of capturing the intrinsic geometrical structure of image, a method of SAR image denoising based on Contourlet domain adaptive BivaShrink model is presented combining Contourlet transform with BivaShrink denoising model. Experimental results show the method achieves better performance at speckle reduction.
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Computer Engineering. 2010, 36(21): 239-241. https://doi.org/10.3969/j.issn.1000-3428.2010.21.086This paper carries out research on the key issues in retargeting and code implementation and develops an industrial quality compiler based on Open64 for embedded PowerPC architecture. According to the test result of gcc-c. torture and SPEC2000, this compiler is close to or reaches GCC on correctness and performance. This work provides good compiling tool support for future research and application, and lays a good foundation for the future work such as automatic retargeting.
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Computer Engineering. 2010, 36(21): 242-244. https://doi.org/10.3969/j.issn.1000-3428.2010.21.087In order to realize routing management during measurement management work in steel enterprise, this paper presents a workflow meta- model based on Finite State Machine(FSM), gives the elements definition and transition principle of meta-model. An instance of workflow and role right for measurement process are constructed according to controlled conditions of the ISO10012 management process, and three-tier Browser/Server(B/S) workflow architecture is developed. Results show that the workflow meets the seven controlled requirements of measurement process.
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Computer Engineering. 2010, 36(21): 245-247. https://doi.org/10.3969/j.issn.1000-3428.2010.21.088It is difficult to collect sufficient labeled E-mails for training a client spam classifier. Aiming at the problem, this paper proposes a spam filtering method based on learning from small samples, which improves the filtering performance with unlabeled samples. An initial Na?ve Bayes(NB) classifier is trained with a dataset of labeled E-mails, and unlabeled E-mails are probabilistically labeled with it. A new classifier is trained with all E-mails, and iterates to convergence with EM algorithm. Experimental results prove that, given labeled small training samples with a size of 5 to 20, the performance of spam filtering can be effectively improved.
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Computer Engineering. 2010, 36(21): 248-250. https://doi.org/10.3969/j.issn.1000-3428.2010.21.089The existing Air Traffic Control Geographic Information System(ATC-GIS) introduces a method of inserting a great amount of new data into R-Tree one by one, which appears inefficient and can not maintain the query performance of R-tree well. Concerning this, an improved data inserting method based on SCB is proposed. The algorithm introduces a technique which uses a seed tree to guide clustering and build input R-tree for bulk inserting, then optimizes the structure of R-tree by repacking. Through the experiments, the STR compression algorithm is selected to build input R-tree. Experimental results show that the improved method outperforms in inserting time and query performance.
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Computer Engineering. 2010, 36(21): 251-253. https://doi.org/10.3969/j.issn.1000-3428.2010.21.090In order to eliminate the influence of duplicated data on transmission and storage, this paper proposes a differential backup method based on duplicated data elimination. By segmenting the block of file into several fixed size according to some interval and using Hash table to identify unique block, Rsync algorithm can detect duplicated data among different files. Local match is realized by segmenting Hash table. Differences transmission between different versions of files is realized by using local checksum file. Experimental results show that, compared with Rsync algorithm, the method can reduce the amount of data transmitted, decrease the disk capacity, and enhance the block search efficiency.
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Computer Engineering. 2010, 36(21): 254-256,259. https://doi.org/10.3969/j.issn.1000-3428.2010.21.091Tourism uses recommender systems to help user acquire their goals by using interactive dialogue. Although present recommender systems’ interactivity has been enhanced, they still use interactive method. This paper presents a universally applicable model, design a conversation recommender system by using reinforcement learning technique which can learn adaptive interactive method automatically. Describe methods recommender systems use and summer up a number of important issues. Results testify the system’s application in Austrian tourism portal.
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Computer Engineering. 2010, 36(21): 257-259. https://doi.org/10.3969/j.issn.1000-3428.2010.21.092As to the problems of low accuracy, heavy load and poor coherence in making the enterprise railway’s shunting trip plan, a computer aided shunting trip plan for enterprise railway system based on MVC and .NET platform is designed. The system is modeled by UML and designed by MVC design pattern, the algorithm of making shunting trip plan is discussed, steps of the realization of binary method are introduced by examples, and the system is developed on ASP.NET platform.
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Computer Engineering. 2010, 36(21): 260-261,264. https://doi.org/10.3969/j.issn.1000-3428.2010.21.093This paper proposes a two-stage Web page summarization approach by exploiting both the page contents and the tags annotated on that page. Observing the mutually reinforcing relationship between quality tags and quality users, it uses a bipartite ranking algorithm to score tags in the first stage, derives a graph representation for tags and sentences on a Web page and applies the Manifold Ranking algorithm to rank sentences and generates the summary accordingly. Experimental results show that the method has significant improvement in summary accuracy.
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Computer Engineering. 2010, 36(21): 262-264. https://doi.org/10.3969/j.issn.1000-3428.2010.21.094This paper proposes a method of detecting industrial axletree quality based on image edge morphologic analysis and recognition technology. The image filter, enhancement and segmentation are adopted to pre-process the image and a novel image coding method based on relative direction coding is presented as well. Furthermore, an improved method based on image edge morphologic analysis is proposed, which can analyze the image edge with large quantities, a neural network classifier is utilized to sort images. Experimental results show that the approach to detecting axletree quality can achieve well recognition effect.
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Computer Engineering. 2010, 36(21): 265-266,269. https://doi.org/10.3969/j.issn.1000-3428.2010.21.095In light of the inadequacy of popular systems of generating summaries, a context-sensitive program is put forward called SSC (Summarizer Sensitive to Context). The program has one characteristic which can reduce the content redundancy maximally and it is sensitive to the context. First the most important sentence is selected as a sentence in summary, and then the weight of terms in the sentence is set to very small constant so as to prevent the recurrence of these terms. ROUGE is used to evaluate the program. The experimental results show that the method has achieved good results.
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Computer Engineering. 2010, 36(21): 267-269. https://doi.org/10.3969/j.issn.1000-3428.2010.21.096As to look for a breakthrough for data transfer rate based on a mature traditional air bus technology, through the description of the Enhanced Bit Rate 1553(EBR-1553), compared with the traditional 1553B bus, the communication system architecture of EBR-1553 bus is analyzed, and the word format and message format of its transfer protocol are introduced. A hardware solution of the enhanced bit rate 1553 bus interface board based on PCI bus is raised, some key circuits of the design are described, and reference for future research and use of EBR-1553 bus are provided.
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Computer Engineering. 2010, 36(21): 270-271,274. https://doi.org/10.3969/j.issn.1000-3428.2010.21.097Memory Management Unit(MMU) which is based on MIPS32 4kc processor is designed. The module checks the address from the processor core, and translates it to physical address statically or dynamically. TLB is the core of dynamical mapping and is implemented by using three stage pipelines. Moreover, ITLB and DTLB which are shadows of JTLB are designed to accelerate address translation. The module and processor are verified on FPGA board running Linux and the hardware cost is about 32K logical gates.
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Computer Engineering. 2010, 36(21): 272-274. https://doi.org/10.3969/j.issn.1000-3428.2010.21.098Aiming at the problem that how to program for complex User Interface(UI) and difficulty in reusing UI control, this paper concludes the principles of interface design of the decoupling, which accords with the principles of agile software development and test requirements, and proposes a unified design concept and its implementation method. By summarizing the level request of interface design and analyzing the design pattern for various modules decoupling, it uses dependency injection technology to make the coupling of system interface modules bottom out, enabling the modules combine nimbly. The interface design of PACS proves that the principles and design method are flexibility and adaptability.
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Computer Engineering. 2010, 36(21): 275-276,279. https://doi.org/10.3969/j.issn.1000-3428.2010.21.099A dynamic and static integrated allocation strategy for scratch pad memory is proposed based on MPSoc. This method statically allocates global variables into SPM using ILP, transforms the set of tasks scheduled to an EDPRG, and the local variables are put using greedy algorithm. Experimental results show the approach can reduce 27% than using pure static method, and about 35% running time than that of system without SPM.
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Computer Engineering. 2010, 36(21): 277-279. https://doi.org/10.3969/j.issn.1000-3428.2010.21.100According to the knowledge discovery of the unstructed information, this paper provides a framework of UIMA-based on knowledge discovery. This framewok intergrates a UIMA analysis pipeline and offers an open and extensive conceptual foundation and infrastructure of the knowledge discovery, in order to extract informal knowledge from the massive unstructed information. It also constructs a knowledge environment of cooperation to implement the analysis of unstructed data with the help of reasoning on knowledge. Based on the framework and OWL, it implements a knowledge discovery prototype about medical system.
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Computer Engineering. 2010, 36(21): 280-282,285. https://doi.org/10.3969/j.issn.1000-3428.2010.21.101This paper provides a scheme of multi-processor embedded system simulation based on Instruction Set Simulator(ISS). By adopting interconnection based on bus and mechanism of sharing global memory, it can efficiently solve the problem of communication between processors. The global clock synchronization is introduced to realize flexibly the schedule for all processing units, which keeps the processors in step. Analysis show that the simulator can simulate and track one or more homologous object code which can also come from different sources.
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Computer Engineering. 2010, 36(21): 283-285. https://doi.org/10.3969/j.issn.1000-3428.2010.21.102One of the key factors that affects the performance of Chip MultiProcessors(CMP) is the design and management of L2 cache. This paper proposes the design method of cooperative caching using central coherence directory hardware based on private L2 cache, which can manage on-chip storage resources more efficiently to improve the performance of CMP. This cooperative caching combines the lower average memory access latency of private cache and the lower miss rate of shared cache, it also has strong scalability. Experimental result shows that on the average, the cooperative caching increases the IPC by 13.5%, compared with shared L2 cache, and the hardware overhead is about 8.1%.
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Computer Engineering. 2010, 36(21): 286-287,290. https://doi.org/10.3969/j.issn.1000-3428.2010.21.103According to the characteristics of job schedule in grid computing, based on LSF system of Platform Company, this paper proposes plug-in mechanism which is suitable for managing job scheduling schemes. It manages the schedule modules in grid system with plug-in because of the merits of plug-in, including easy to extent and implement and plug-and-play, so that the performance of the whole system is improved and friendly interfaces to the third party is provided.
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Computer Engineering. 2010, 36(21): 288-290. https://doi.org/10.3969/j.issn.1000-3428.2010.21.104Aiming at the H3MP16 multi-core processor, this paper designs a streaming media presenting system to test the performances of it. It introduces the hardware structure of the H3MP16 multi-core processor, explains the frame and the function of the test system, and then discusses the design solutions. It proposes a program to send and capture packets based on socket communication, and performs the online synchronous transfer and display of FFMPEG, tests the packet loss rate and playing effects. It succeeds to provide an effective test platform for multi-core processor.
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Computer Engineering. 2010, 36(21): 291-封三. https://doi.org/10.3969/j.issn.1000-3428.2010.21.105This paper proposes a development model for virtual laboratory based on ColdFusion. It uses Flash as the client side to improve users’ experience and animate the experimental output, applies ColdFusion as the server side, and uses JavaBean, COM/DCOM, CORBA Object or ColdFusion component as the computing tools in the server side, which can improve the efficiency of developing a virtual laboratory markedly. Experimental results prove that the designers can design and develop a new virtual laboratory fast, and users can do experiments without the limitation of time, place and experimental equipments by using the model.
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