05 June 2012, Volume 38 Issue 11
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Computer Engineering. 2012, 38(11): 1-4. https://doi.org/10.3969/j.issn.1000-3428.2012.11.001Now existing access control scheme has the strong dependence to trusty third party in cloud. With regard to this problem, this paper proposes an access control scheme based on attribute. It designs an access control model in cloud, constructs an access control policy which adopts the way of Attribute-based Encryption(ABE) tree, and presents a method of user revocation and policy updates. Security analysis indicates that the scheme has the features of collusion-resistance, data confidentiality and backward and forward secrecy.
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Computer Engineering. 2012, 38(11): 5-7. https://doi.org/10.3969/j.issn.1000-3428.2012.11.002To solve the problem of excessive virtual machine migration and not extend to the large-scale cluster by the centralized management method of virtual machine in cloud data center, this paper proposes a distributed management method of virtual machine for energy-saving. The distributed management method includes the local management and the global management. The local management is responsible for monitoring the hosts of data center and deciding whether to migrate a virtual machine by the high threshold and the low threshold. The global management is responsible for migrating the virtual machine to the physical node which consumes the least power after the migration. Experimental results show that the distributed management method can reduce the number of virtual machine migration and improve the quality of service while achieving better energy efficiency in cloud data center.
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Computer Engineering. 2012, 38(11): 8-10. https://doi.org/10.3969/j.issn.1000-3428.2012.11.003Users usually can only provide incomplete preference information to service providers. In order to carry out effective cloud services composition, this paper proposes an incomplete user preference information weight fixing algorithm. It gets the incomplete information, obtains the user subjective and objective weight by rough set method and then gets the user preference service composition. The algorithm is used in cloud computing platform, and achieves good results.
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Computer Engineering. 2012, 38(11): 11-13. https://doi.org/10.3969/j.issn.1000-3428.2012.11.004To the problem that traditional Genetic Algorithm(GA) has early convergence, this paper proposes an improved Cellular automata Genetic Algorithm(CGA), and applies on resource schedule under cloud environment. It makes a discussion on the enormous tasks required by users group and how to allocate resources reasonably, takes use of CGA to search for the optimal resource schedule proposal. Experimental results under the simulator platform CloudSim shows that the algorithm can reduce the whole makespan and decrease the costs of users, which is an effective resource schedule satisfying cloud environment.
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Computer Engineering. 2012, 38(11): 14-16. https://doi.org/10.3969/j.issn.1000-3428.2012.11.005There exist the problems of difficulties in evidence obtaining and numerous logs to be dealt with in computer forensics. Aiming at these problems, this paper introduces the cloud computing into computer forensics, proposes a Cloud Forensics Model(CFM). CFM obtains evidence by making use of Agent technology, which can increase autonomy and intelligence of evidence acquisition. It improves the forensics efficiency and the safety of computer evidence by using the virtualization technology and collaboration technology. It introduces the feedback technology, which can consummate the evidence collection system. Experimental results prove the validity of the model.
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Computer Engineering. 2012, 38(11): 17-19. https://doi.org/10.3969/j.issn.1000-3428.2012.11.006Hosts are usually selected only based on hosts’ current CPU conditions using traditional method. It brings load imbalance caused by the irrational use of resources. Aiming at this problem, this paper presents a virtual machine deployment mechanism in cloud platform. The model which can automatically select host is established. The automatic selection strategy is based on the individual needs, and it can predict follow-up load and resource consumption of virtual machines. Experimental results show that the mechanism can meet the users’ requirement and improve the system performance.
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Computer Engineering. 2012, 38(11): 20-22,26. https://doi.org/10.3969/j.issn.1000-3428.2012.11.007This paper proposes a cryptographic access control scheme based on attribute group in cloud storage. The symmetric cryptosystem is used to encrypt the original data by the Data Owner(DO), and the attribute-based encryption algorithm is used to encrypt the symmetric key. DO delegate the task of data re-encryption to the Cloud Service Provider(CSP), which not only reduces the computational cost of DO, but also does not reveal extra information of the plaintext to CSP. The proposed scheme supports the unit of a collection of multiple users when any attribute or user is revoked. The fine-grained and flexible access control can be achieved by hybrid cryptosystem meachanism. Compared with the existing access control schemes, the proposed scheme is more efficient in revocation cost and can alleviate the administering burders on DO. The scheme guarantees collusion resistance against colluding users, data confidentiality, forward and backward secrecy.
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Computer Engineering. 2012, 38(11): 23-26. https://doi.org/10.3969/j.issn.1000-3428.2012.11.008This paper designs a management system for ICCS-PW cloud server, which can manage power, storage, switch, and system monitoring in one platform by using a combination of hardware and software methods, AJAX, Common Gateway Interface(CGI), custom communication protocols and other technologies. The implementation of this system is divided into three levels: management software, I2C bus and controller chip. The system is tested with LoadRunner, and the results show that the management system can meet the requirements of the application.
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Computer Engineering. 2012, 38(11): 27-29,37. https://doi.org/10.3969/j.issn.1000-3428.2012.11.009Map-Reduce model does not consider the computing performance in large number of heterogeneous nodes when allocating the input files in the cluster, and this leads to network data transfer increase to run the map task. Addressing this issue, this paper proposes the improved Map-Reduce model under the cloud computing environment. For a large number of nodes in the cluster calculation with different performance, it raises the maximum computational time minimal objective function model, uses Genetic Algorithm(GA) to solve the model to get the distribution plan. Simulation results prove the validity of the model.
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Computer Engineering. 2012, 38(11): 30-33. https://doi.org/10.3969/j.issn.1000-3428.2012.11.010The Role-based Access Control(RBAC) is widely applied because of its advantages. For the unsuitability of RBAC in inter-organization environment, the main propose of this research is to extend the characteristics of RBAC on intra-organization workflow. The research puts forward a role score mechanism, and appends more strict constraint to users, roles and activities of horizontal inter-organization workflow. Besides, this research makes sure that a user chooses an appropriate role from virtual role set to execute activity in inter-organization workflow. Proved by the experiment, the extension is simple and effective, and it makes the enterprises more equitable and securable in inter-organization workflow.
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Computer Engineering. 2012, 38(11): 34-37. https://doi.org/10.3969/j.issn.1000-3428.2012.11.011To address the problem of recommendation algorithm computing readers similarity or books similarity with low accuracy and recommendation quality, Personalized recommendation algorithm based on multi-feature is proposed. It computes books similarity based on Chinese library classification method and books feature vector, computes readers similarity based on readers feature vector and borrow records. Based on this, two prediction results are produced. The last recommendation is produced to readers by weight of this two prediction results. Experimental result shows that the proposed algorithm achieves more recommendation accuracy on books.
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Computer Engineering. 2012, 38(11): 38-41. https://doi.org/10.3969/j.issn.1000-3428.2012.11.012To realize the personalized recommendatory service effectively, the content-based filtering recommendatory technology is adopted in the design process of the agriculture information recommendation system. A new user comprehensive interest model is presented. The model can calculate the similarity of user and the document by the synthetically weights of background, reading and operation behavior factors of users, and recommend document to users based on this. By the practical tests, the results show that increasing the weights of user’s reading and operating behavior in model can effectively improve the recommended precision.
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Computer Engineering. 2012, 38(11): 42-44,47. https://doi.org/10.3969/j.issn.1000-3428.2012.11.013An Automatic Tags Extraction(ATE) component expression is proposed, and a fuzzy clustering method of components is designed based on the ATE. The ATE expression which contains more effective information can overcome the effect of subjective factors in faceted classification. The ATE clustering, breaking the rigid division mode with permitting a component to be classified into more than one cluster, can provide better support for components retrieval than traditional components clustering. Through the experiment in prototype component repository, the feasibility and efficiency of ATE clustering are validated.
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Computer Engineering. 2012, 38(11): 45-47. https://doi.org/10.3969/j.issn.1000-3428.2012.11.014To select the appropriate views to be materialized in the data warehouse, a new estimation of distribution algorithm is proposed. It generates initial solutions, the initial population uniformly distributed in the solution space, selects some of the individuals according to their fitness, and builds a posterior probability distribution model of promising solutions. New solutions are sampled from the model thus built and fully or in part replaced the old population. Experimental results show that the algorithm reduces the total query response time and maintenance cost, and outperforms canonical genetic algorithm.
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Computer Engineering. 2012, 38(11): 48-50. https://doi.org/10.3969/j.issn.1000-3428.2012.11.015When the amount of data from GB goes up to TB level or even PB level, parallel database with high performance cost too much in order to achieve scalability and fault tolerance. To address the problem, this paper designs a parallel database engine——FlexDB, which is based on Map Reduce. The parallel computing framework of Map Reduce is as a communication layer of FlexDB which is to assign computing tasks and coordinate communications among all nodes in cluster. Experimental results show that the FlexDB system performance is close to parallel database, and has good expansibility and fault tolerance.
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Computer Engineering. 2012, 38(11): 51-52,55. https://doi.org/10.3969/j.issn.1000-3428.2012.11.016Aiming at K-link Shortest Path(K-SP) problem on n intervals, this paper presents the on-line algorithm for K-SP problem on interval graphs. It studies the properties about interval graphs and the shortest path problem on interval graphs, is based on the intuition of dynamic programming and greedy algorithms to optimize on-line algorithm complexity. Theoretical analysis result shows the complexity of this algorithms is O(nK+nlgn), same as the best off-line algorithm for this problem.
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Computer Engineering. 2012, 38(11): 53-55. https://doi.org/10.3969/j.issn.1000-3428.2012.11.017There exist constraint relations among parameters for most of the software system under test. If these relations are not taken into account, some of the combinations in the test suite make no sense. Therefore this paper proposes a combination test method in presence of parameter constraints. The method uses backtracking algorithm to traverse the tree and meanwhile the branches of solution space tree are cut using the constraint relations among parameters to avoid invalid test cases. Then some test data is added into the test case by a greedy algorithm to cover all the uncovered pairs. Experimental result shows that this method can reduce the generation number of test cases, and improve the efficiency of test.
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Computer Engineering. 2012, 38(11): 56-58. https://doi.org/10.3969/j.issn.1000-3428.2012.11.018Based on classical CLARANS clustering algorithm, a new clustering algorithm of uncertain objects is proposed in this paper. In the algorithm, each uncertain object is given as a Gaussian Mixture Model(GMM) which is the weighted sum of Gaussian distribution, and Kullback-Leibler Divergence(KLD) is used as distance measure between uncertain objects. Experimental result of image dataset shows the higher clustering precision of algorithm.
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Computer Engineering. 2012, 38(11): 59-61,65. https://doi.org/10.3969/j.issn.1000-3428.2012.11.019Relative knowledge quantity is defined under incomplete decision table, and the definition of the important degree of attributes is obtained. A heuristic algorithm based on relative knowledge quantity for reduction of attributes is presented. This algorithm reduces the time consumption through reducing the scale of data. Experiment on the UCI data set demonstrates the improvements of the reduction efficiency, especially for the data sets with large scale.
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Computer Engineering. 2012, 38(11): 62-65. https://doi.org/10.3969/j.issn.1000-3428.2012.11.020This paper proposes a constraint power set concept based on power set theory, and proposes an algorithm of mining frequent Neighboring Class Set(NCS) depending on constrain power set. The algorithm uses computing constraint power set mapping to generate candidate frequent NCS and computes its support count. It not only avoids generating redundant candidate, but also reduces calculation amount of repeated scanning database. Experimental result indicates that the algorithm is faster and more efficient than present mining algorithm when extracting constraint frequent NCS.
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Computer Engineering. 2012, 38(11): 66-68. https://doi.org/10.3969/j.issn.1000-3428.2012.11.021Directed Acyclic Graph(DAG) is used to represent the dependencies between the subtasks for scheduling in parallel programming. To enhance reuse of DAG pattern in DAG data driven model, this paper proposes a plug-in DAG pattern library which separates the DAG pattern module from the runtime system module. The new library improves the reusability and the scalability of this model. It is implemented in Easy PDP, and proves this technology can reduce the cost to extend the system by solving checkerboard problem.
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Computer Engineering. 2012, 38(11): 69-72. https://doi.org/10.3969/j.issn.1000-3428.2012.11.022An event-driven data gathering protocol in mobile wireless sensor networks is proposed. The protocol uses the adaptive cluster head evaluating model to elect cluster head. Upon interesting events take place, the member nodes gather them and send to the cluster head. After fusing these data, the cluster head transmits a data collection request packet to the sink. When receiving this packet, the sink moves to the cluster head nearby and gathers data. Both theoretical analysis and simulation studies show that this protocol can prolong to network lifetime efficiently.
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Computer Engineering. 2012, 38(11): 73-76. https://doi.org/10.3969/j.issn.1000-3428.2012.11.023Based on Baidu system, the accurate localization/position technology is discussed about how to use it to design a geography position routing algorithm. By using greedy policy and geography position information, a new QoS-supported routing algorithm is designed for Wireless Multimedia Sensor Networks(WMSNs). As the main novel point, the algorithm guarantees an end-to-end delay upper bound for real-time communication inspired from SPEED firstly. Then a cost function is introduced to provide QoS support and balance the energy, lifetime, and the bandwidth performance. The soft/hard delay and others QoS parameters of the algorithm are analyzed in theory, and results show that the algorithm can provide more QoS supports for multimedia communication in WMSNs.
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Computer Engineering. 2012, 38(11): 77-79,84. https://doi.org/10.3969/j.issn.1000-3428.2012.11.024The traditional rate adaptive algorithm can not select the appropriate transmission rate under the vehicular network of which channel quality changes quickly. This paper proposes a rate adaptive algorithm for vehicle to roadside network. The algorithm is based on Receive Signal Strength Indication(RSSI) of transmitting terminal to predict and select rate, Roadside Unit(RSU) of transmitting terminal measures RSSI value of received ACK messages to predict next time transmission channel quality. Simulation results show that the algorithm for channel quality prediction can achieve higher accuracy and higher system throughput under different degree of channel fading, compared with RBAR algorithm and SampleRate algorithm.
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Computer Engineering. 2012, 38(11): 80-84. https://doi.org/10.3969/j.issn.1000-3428.2012.11.025For the network structure and distributed resource of communication grid, this paper proposes a resource management technology based on Quality of Service(QoS) and multi-layer cooperation. The technology achieves sharing information from combining admission control, route selection and resource reservation. It utilizes resource fully and tries its best to guarantee the requirement of client. Simulation result shows that the transmission performance of data is improved by this technology.
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Computer Engineering. 2012, 38(11): 85-87. https://doi.org/10.3969/j.issn.1000-3428.2012.11.026Aiming at the problem that Wireless Sensor Network(WSN) need solve the automatic adjustment of routing request zone, this paper presents a dynamic hybrid search-based self-adaptive routing algorithm for WSN. According to the return state of routing discovery, the proposed algorithm sets the radius of cylindrical request zone as the parameter and makes use of the combination of binary search and exponential search to realize the self-adaptation of the routing request zone. Simulation results show that the proposed algorithm performs better than AODVjr routing algorithm for packet delivery ratio, routing overhead, and average packet delay.
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Computer Engineering. 2012, 38(11): 88-90. https://doi.org/10.3969/j.issn.1000-3428.2012.11.027A new variable step-size algorithm is proposed to reduce the residual error and the phase error caused by the mismatch of the Constant Modulu Algorithm(CMA) and constellations of the high-order QAM signals. The new algorithm takes the error energy as the step-size control criteria to get a balance between the convergence rate and the residual error. Simulation experimental result shows that compared with other blind equalization algorithm, the new algorithm gets a better residual error and phase recovery, and keeps the robustness unchanged.
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Computer Engineering. 2012, 38(11): 91-93. https://doi.org/10.3969/j.issn.1000-3428.2012.11.028Dual Carrier Modulation(DCM) technology is chosen as the higher data rate modulation technology in Wireless USB system. Different demodulation methods for the DCM are presented, including soft bit, Maximum Likely(ML) soft bit and Log Likelihood Ratio(LLR). Frequency diversity and Channel State Information(CSI) are further technologies to enhance the system decoding. Experimental results show that using LLR demodulation methods with frequency diversity and CSI decoding technologies can maximize system transmission performance.
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Computer Engineering. 2012, 38(11): 94-95. https://doi.org/10.3969/j.issn.1000-3428.2012.11.029This paper proposes an IPv6 address auto-configuration scheme for 6LoWPAN Wireless Sensor Network(WSN). In the scheme, the transmission scope of the control packets is controlled within one-hop scope and the scheme neither records the address allocation status nor performs the duplicate address detection, so the address configuration cost is reduced and the address configuration delay is shortened. Based on the proposed IPv6 address structure, the paper proposes the address recovery algorithm. From the perspectives of the address configuration cost and address configuration delay, the paper analyzes and compares the performance parameters of the proposed scheme and the existing schemes, including MANETConf, Strong DAD and LISAA. Performance analytical results prove the feasibility and the efficiency of the proposed scheme.
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Computer Engineering. 2012, 38(11): 96-99,103. https://doi.org/10.3969/j.issn.1000-3428.2012.11.030A Partially Observable Markov Decision Process(POMDP)-based online node scheduling algorithm is proposed to address the problem of limited energy supply and the uncertainty of perception in target tracking Wireless Sensor Network(WSN). The algorithm represents the uncertainty of moving target using state transition and observation function, and uses reward function to balance the tracking performance and node energy consumption. In order to solve the scheduling policy online, it constructs reachable belief AND/OR tree with limited depth to reduce computational complexity. Experimental results show that this algorithm can achieve a good tradeoff between the target tracking quality and the node energy consumption while sufficing real-time demand.
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Computer Engineering. 2012, 38(11): 100-103. https://doi.org/10.3969/j.issn.1000-3428.2012.11.031The mobile anchor node planning path exists the node access repetition, and can not improve the localization accuracy. In order to solve this problem, this paper puts forward Mobile Anchor node Path Planning(MAPP) algorithm, quotes the graph theory knowledge, translates sensor nodes into figure vertices, and combines with the ant colony algorithm, uses graph traversal to solve the problem of path planning, looks for a path. Experimental results show that the algorithm can locate the whole sensor nodes, meanwhile avoid the repetition of access, and reduce nodes localization error.
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Computer Engineering. 2012, 38(11): 104-106. https://doi.org/10.3969/j.issn.1000-3428.2012.11.032Aiming at the problem of the Received Signal Strength Indication(RSSI) model depending on the signal attenuation factor, this paper puts forward an environment self-adaptive localization algorithm. With the improved RSSI method, the signal attenuation factor which impacts the precision of the localization algorithm is eliminated through the quantitative relationship between the edges and the algorithm can realize awareness of the environment. Simulation experimental result shows that the improved localization algorithm has higher precision and stronger self-adaptability than traditional MDS-MAP algorithm.
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Computer Engineering. 2012, 38(11): 107-110,113. https://doi.org/10.3969/j.issn.1000-3428.2012.11.033For the fault of S-MAC protocol in energy-consume unbalance between nodes, a cross-layer optimization MAC protocol based on energy-consume balance(BS-MAC) is proposed. The new mechanism adds the new variable TS to record the number of times that the node becomes virtue clusters’ boundary. Nodes sleep/listen adaptively through comparing TS with their neighbor nodes. BS-MAC adjusts the balance of energy-consume cross-layer with the clustering algorithm which adds TS. Numerical analysis shows that BS-MAC not only increases the balance of the nodes’ energy consumption, reduces the nodes’ mortality and extends the network life time, but also keeps the same energy-consume and delay with the S-MAC.
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Computer Engineering. 2012, 38(11): 111-113. https://doi.org/10.3969/j.issn.1000-3428.2012.11.034This paper proposes a P2P access hotspot load balance method based on query request analysis. A single-exponent smoothness method is adopted to predict the future hotspots through time series analysis of history query data, and then the combination strategy of end-to-end copy and light-load neighbor node copy is adopted to balance load according to the query request behaviors, which effectively prevent and eliminate the load imbalance caused by access hotspots. Experimental results validate the proposed method is effective.
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Computer Engineering. 2012, 38(11): 114-116. https://doi.org/10.3969/j.issn.1000-3428.2012.11.035For the routing problem of Wireless Sensor Network(WSN), a standard Dynamic Programming(DP) model is built based on the dynamic programming idea, a minimal energy consumption and energy balancing routing algorithm are proposed. It dynamically adjusts the decision set according to the average residual energy at each stage, and selects the optimal decision so that the energy consumption is the minimal. Experimental results prove that the routing algorithms can improve the stable period of network, and save energy of network to some extent.
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Computer Engineering. 2012, 38(11): 117-119. https://doi.org/10.3969/j.issn.1000-3428.2012.11.036This paper analyzes the network reliability algorithm based on pathset matrix, and there exists a serious combination explosion problem in this algorithm. Aiming at this problem, it proposes a network reliability algorithm based on pathset matrix and boolean operation. The concept of bit vector is introduced. In addition, the pre-process of special pathsets and count of all-one bit vectors are also implied. Experimental results show that it not only increases the memory utilization, reduce the redundancy but also relieve the combination explosion problem in some degree.
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Computer Engineering. 2012, 38(11): 120-123. https://doi.org/10.3969/j.issn.1000-3428.2012.11.037Unstability of wireless link and the noncooperation of malicious nodes disturb the implementation of anonymous communication in mobile P2P networks. To solve this problem, by improving the structure of mobile P2P network, a self-adaptive anonymous algorithm named Network Condition Sensing-based Crowds(NCS-Crowds) is proposed. On this basis, by synthetically using Kna mapping and palliative flows, a mutual anonymous communication scheme based on System Architecture Evolution(SAE) is proposed to protect user’s privacy. Theory analysis and simulation results show that the scheme can achieve expectant anonymity with reasonable overhead.
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Computer Engineering. 2012, 38(11): 124-125,129. https://doi.org/10.3969/j.issn.1000-3428.2012.11.038This paper is based on the normality of generalized Bent functions, combines the characteristic functions of linear subspace. The Chrestenson spectral characteristics of generalized normal Bent functions are studied. According to the indirect construction method, two new classes of generalized Bent functions of n variables over integers module m residue class Zm and p meta-field Zp are presented. Theory analysis result shows that more generalized Bent functions can be constructed by using the proposed construction method compared with the traditional construction method.
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Computer Engineering. 2012, 38(11): 126-129. https://doi.org/10.3969/j.issn.1000-3428.2012.11.039Aiming at the multi-grade characteristics and the security problems of the Agent system, a set of security mechanisms is designed. The security of Agent system is actualized by making communication rules, establishing an upper to lower mechanism and using encryption algorithm. By using Python language, this paper develops a Graphical User Interface(GUI) as the Agent platform, and the performance of the security mechanism is analyzed in theory and practice. Results show that the security mechanism can effectively ensure the security of Agent system.
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Computer Engineering. 2012, 38(11): 130-132. https://doi.org/10.3969/j.issn.1000-3428.2012.11.040Botnet has two features of scale-free network, so this paper proposes a construction method of scale-free semi-distributed P2P Botnet. It allows the bot program to infect a few hosts, after that, each infected host choose the node according to its degree. The degree is larger, the probability of selection is higher. Theoretical analysis and simulation results show that the Botnet constructed by the method has the features of scale-free network.
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Computer Engineering. 2012, 38(11): 133-135. https://doi.org/10.3969/j.issn.1000-3428.2012.11.041In the forward-secure blind signature scheme proposed by Zhang Xi et al, there is an error in module arithmetic in blind signature generation phase, so the scheme does not meet verifiability; the attacker can generate blind signature of any messages, so it does not satisfy unforgeability. This paper proposes an improved blind signature scheme by optimizing the system parameters, modifying the module arithmetic and reducing the signature data. Security and efficiency analysis results show that the improved scheme satisfies unforgeability, blindness and forward-security, and has high calculating efficiency.
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Computer Engineering. 2012, 38(11): 136-138. https://doi.org/10.3969/j.issn.1000-3428.2012.11.042In order to realize the user’s identity control of digital products in the distribution, circulation, buying processes in tri-networks integration environment, according to the requirements of security and flexibility of Digital Rights Management(DRM), by using the smart card technology and improving user’s ID control and management solution, this paper proposes an ID control and management solution of DRM. Theoretical and experimental results show that the solution is safe, reliable, and it can ensure the digital products’ legitimate interests of authors, circulation and users.
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Computer Engineering. 2012, 38(11): 139-142. https://doi.org/10.3969/j.issn.1000-3428.2012.11.043To effectively cope with the curse of dimensionality problem of face recognition, a face recognition algorithm based on adaptive Kernel Marginal Fisher Analysis(KMFA) is proposed in this paper. The adaptive kernel function which closely relates to image data is first introduced by considering the image manifold structure, then the high-dimensional face images are nonlinearly reduced to the lower-dimensional feature space with KMFA. Least Squares Support Vector Machine(LS-SVM) is used to classify and recognize different face image herein. Experimental results show that the proposed algorithm performs much better than other traditional face recognition algorithms.
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Computer Engineering. 2012, 38(11): 143-146. https://doi.org/10.3969/j.issn.1000-3428.2012.11.044In order to prevent the criminal behaviors for Automatic Teller Machine(ATM) timely, this paper designs an ATM intelligent video surveillance system based on hand trajectory recognition. A background model is built by Gaussian-mixture background modeling method with the video images collected in the monitored area, and the information of human body can be obtained by background subtraction method and tracking algorithm. By analyzing the area change of human body, it can judge whether there exist abnormal behaviors. If there is, it will give an alarm. Otherwise, it will detect the hand trajectory with the skin detection algorithm based on color space and some location constraints, then match and recognize the movement trajectory of hand by building an Hidden Markov Model(HMM) to determine whether there exist other abnormal behaviours further. Experimental results show that the recognition rate for the criminal behaviors of the method proposed can reach up to 88%.
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Computer Engineering. 2012, 38(11): 147-149,152. https://doi.org/10.3969/j.issn.1000-3428.2012.11.045In view of the shortcomings of existing Bus Arrival Time Prediction(BATP) model, this paper proposes a novel BATP model based on condition mapping. The model maps traffic information to arrival time directly, which makes it have the advantage of simpleness, high degree of fitting and strong generalization ability. It proposes an algorithm for the model based on Case-based Reasoning(CBR), and testes the algorithms with actual data. Experiments in the peak and normal times show that the prediction accuracy of the algorithm is 100% and 85%, and the average deviation is 13 seconds and 30.5 seconds respectively.
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Computer Engineering. 2012, 38(11): 150-152. https://doi.org/10.3969/j.issn.1000-3428.2012.11.046This paper focuses on the iterant problems emerged in the process of generating a test paper and an effective method which is called iterant problems optimization strategy is proposed. This method contains two main procedures, which are iterant problems identification and iterant problems replacement. The method can replace iterant problems of one test paper quickly, and at the same time maximize the retention of the advantages of the whole paper. The experiment data show that algorithm which adopts this iterant problems optimization strategy can accelerate the process of generating test paper, and it also can improve the satisfaction of test paper generated.
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Computer Engineering. 2012, 38(11): 153-155,159. https://doi.org/10.3969/j.issn.1000-3428.2012.11.047Particle filtering is taken as the main solution for solved infrared target tracking problems in nonlinear/non-Gaussian system. The selection of number of particle set directly influences on the tracking effect on which particle filtering dose in high real-time system. Based on the problem, a novel algorithm based on hypothesis test in auto-adaptive particle filtering is proposed for target tracking in infrared imagery real-time system. According to the hypothesis test problems, the number of particle set is dynamic got, which works out the problem of high time consume that larger number of particle set is taken. Experimental results performed on several infrared image sequences show the robustness and better real-time performance of the proposed algorithm.
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Computer Engineering. 2012, 38(11): 156-159. https://doi.org/10.3969/j.issn.1000-3428.2012.11.048In order to suppress the of multi-mode noise, this paper proposes a Normalized Mixed-norm Filtering Algorithm(NMNF) based on the analysis of the LMF algorithm and LMAD algorithm based on different error criterion. This algorithm adopts a cost function parameters of the introduction of hybrid, and mixing parameters can be adjusted to get the best filtering algorithm. It establishes of a step change in parameters with the input SNR nonlinear function. Simulation results show that, relative to the Gaussian filtering environment, the algorithm in multi-mode noise environment significantly improves robustness.
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Computer Engineering. 2012, 38(11): 160-162,166. https://doi.org/10.3969/j.issn.1000-3428.2012.11.049A novel phonological attribute detection method based on long-term information is presented. This method is comprised of high-level and low-level Time-delayed Neural Networks(TDNN). The low-level TDNN carries out phonological attribute detection on the basis of short-term features, and the high-level TDNN is based on the low-level output and considering the long-term information, and fully taps the relation between speech signals in time. Experimental results show that, compared by the detection using short-term features, the introduction of phonological attribute based on long-term features improves detection rate with 3%. In addition, this paper puts the phonological attribute in phoneme recognition experiments, the results improveing 1.7% in Hidden Markov Model(HMM)-based speech recognition system.
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Computer Engineering. 2012, 38(11): 163-166. https://doi.org/10.3969/j.issn.1000-3428.2012.11.050Situation valuation is the most difficult issue in all kinds of computer game programs. A valuation method named BP-TD(?) is presented combining temporal difference algorithm and back propagation neural network, which can solve the problem of adjusting the parameter values of valuation function. On this basis, in order to enhance the performance of game training, the strategy of setting different parameter values is proposed for opening and middle game phases. The game system RenjuTD is implemented using Renju as application background. Experimental results show the game level of program is significantly improved.
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Computer Engineering. 2012, 38(11): 167-169. https://doi.org/10.3969/j.issn.1000-3428.2012.11.051This paper proposes a unified and automatic approach for extracting Web news object. By extracting the category, title, date, source, author, content, comments, related links and news links in the news pages as category properties, and through page analysis, candidate extraction and true value identification, news object can be extracted automatically. Experimental results show that the method for extracting information of objects multiple properties has high accuracy, and the result does not depend on a specific page template.
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Computer Engineering. 2012, 38(11): 170-172,176. https://doi.org/10.3969/j.issn.1000-3428.2012.11.052Aiming at the optimal selection problem of time delay for temporal blind source separation, a novel method of optimal selection of time lags based on Quantum Genetic Algorithm(QGA) is proposed. The chromosome is adopted. The random observation the quantum collapse combines with time delay to structure populations. After simultaneous approximate diagonalization of several second order correlation matrices, the fitness function based negentropy is constructed. Chromosome update is achieved through quantum rotating gate. Simulation experimental result shows that QGA has more rapid convergence and better global search capacity than other algorithms.
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Computer Engineering. 2012, 38(11): 173-176. https://doi.org/10.3969/j.issn.1000-3428.2012.11.053Aho-Corasick automata algorithm has to backtrack for multiple times to shift to the effective subsequence state when it fails in one pattern matching. In order to solve this problem, this paper proposes a fast multiple patterns matching algorithm based on Aho-Corasick automata. The improved algorithm builds the subsequence pointers for each state. On failing matching, it can shift to the effective subsequence state through the subsequence pointers efficiently, which can reduce backtracking times in Aho-Corasick automata. Furthermore, the proposed algorithm achieves information such as matching length, matching times etc for each state during building automata by dynamic programming methods. Based on this information, the algorithm can calculate the repeated times of pattern strings, earliest position of pattern strings. Experimental results show that the algorithm has advantages of matching accuracy, efficiency, and supporting on-line operation.
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Computer Engineering. 2012, 38(11): 177-179. https://doi.org/10.3969/j.issn.1000-3428.2012.11.054The traditional finite division can not reflect the distribution of positive and negative samples. In this paper, a new continuous AdaBoost algorithm based on minimum class variance is developed. The new algorithm measures the similarity of the sample through calculating the class variance of every finite division in the process of finite division and selectes the best finite division corresponding to the minimum sum of class variance. Simulations show that the algorithm is of better detection rate and faster convergence.
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Computer Engineering. 2012, 38(11): 180-182,185. https://doi.org/10.3969/j.issn.1000-3428.2012.11.055In order to perfect the convergence theory of Cuckoo Search(CS) algorithm, the Markov chain model of the CS algorithm is established and the property of the limited and homogeneous of Markov chain is analyzed. On the basis of this, through the analysis of the state transition process of a group of nest position, the stochastic sequence enters to the optimal state set. And CS algorithm meets the global convergence qualification of random search algorithms. Simulation experimental results show that CS algorithm achieves the global optimization, and the global convergence is ensured.
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Computer Engineering. 2012, 38(11): 183-185. https://doi.org/10.3969/j.issn.1000-3428.2012.11.056This paper gives an improved stereo matching algorithm. According to the polar constraint of disparity field, it obtains the initial disparity map based on line-segmentation, and uses the cross detection technology and credibility constraints to acquire the high reliability GCP pixel. To eliminate the unreliable disparity, the paper uses adaptive weighted median filter which is based on the Bilateral Filter and votes the disparity in the region segment which is obtained through mean shift algorithm. This strategy curbs the outlier effectively and obtains the more reasonable disparity map. Test result on Middlebury test set shows that the algorithm improves the performance greatly and has better accuracy.
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Computer Engineering. 2012, 38(11): 186-188,195. https://doi.org/10.3969/j.issn.1000-3428.2012.11.057Hadoop configuration is a NP-hard combinatorial optimization problem. Aiming at the configuration problem, a configuration optimization strategy is proposed. To ensure that the algorithm not only can search in the local, but also can avoid failing into local optimum, it selects different criteria values and different iteration times to do experiment, so as to search out the values making Hadoop performance optimal. Experimental results show that optimal configuration derived from the algorithm can effectively improve the performance of Hadoop, and has good stability.
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Computer Engineering. 2012, 38(11): 189-191. https://doi.org/10.3969/j.issn.1000-3428.2012.11.058In order to make better use of Julesz’s texton concept to describe the image content for image retrieval, this paper presents a new method, namely Local Structure Histogram(LSH), to describe image features. It converts color image from RGB color space to HSV color space, and extracts colors information and edge orientation in HSV color space. It defines five textons types for local structures detection, and uses histogram to represent image features. Experimental results show that the performance of the method is better than that of local binary pattern histogram and Gabor filter method.
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Computer Engineering. 2012, 38(11): 192-195. https://doi.org/10.3969/j.issn.1000-3428.2012.11.059In order to solve the problem of multi-level segments reference in process of information extraction of engineering drawings, this paper extracts reference segment information based on the Depth First Search(DFS). Relationships establishing arithmetic of reference segments is put forward by analysis of relationships of multi-level reference segments. Definition of node depth, judgment method of target node and specific search strategy of reference segments are expounded. A new searching algorithm of reference path is put forward and a concrete searching arithmetic flow is given. By the new method, a software unit is developed, and information extraction is carried on to a large number of engineering drawings which contains reference segments. Application results show that the new method can realize overall and accurate extraction of reference segments information.
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Computer Engineering. 2012, 38(11): 196-198. https://doi.org/10.3969/j.issn.1000-3428.2012.11.060In order to deal with the problem that the spatial information and spectrum information are hard to be combined when remote images are fused, this paper presents a remote sensing image fusion algorithm based on Nonsubsampled Contourlet Transform(NSCT) and Pulse Coupled Neural Network(PCNN). This algorthm uses different criteria to fuse the high and low frequency components of multi-spectral and high-resolution image which are decomposed by NSCT. Simulation results show that the proposed algorithm can effectively retain the image spectral information and improve the image spatial resolution greatly.
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Computer Engineering. 2012, 38(11): 199-201. https://doi.org/10.3969/j.issn.1000-3428.2012.11.061In order to extract effective features for texture description and classification, this paper proposes a texture feature extraction method fused with Local Binary Pattern(LBP) and Gray-level Co-occurrence Matrix(GLCM). The texture image is processed by rotation invariant LBP operator. The LBP image is obtained and its GLCMs are calculated. Contrast, correlation, energy and inverse difference moment are imposed for texture description. Experimental results show that, compared with other methods, the proposed method is more effective in texture feature extraction and the average classification accuracy reaches to 93%.
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Computer Engineering. 2012, 38(11): 202-204,207. https://doi.org/10.3969/j.issn.1000-3428.2012.11.062In the case that sample is out of database, retrieval precision of the existing image retrieval methods based on linear manifold learning has smaller increase after feedback. Aiming at this problem, this paper proposes an image retrieval method based on Relevance Feedback(RF) and manifold reconstruction. It reconstructs sample into structure graph which needs to be reserved by computing the nearest neighbor in relevance feedback, thus can meet the need of that the distance between similar images and sample is mapped as near as possible. Experimental result shows that the method can improve retrieval precision while merely increase milliseconds time.
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Computer Engineering. 2012, 38(11): 205-207. https://doi.org/10.3969/j.issn.1000-3428.2012.11.063Aiming at the problem of limited data resourse and lower precision of registration of the present super-resolution reconstruct method, combined with the abundant spectral information of remote sensing image, an improved super-resolution reconstruction method is proposed. It uses cross correlation between two bands, which is useful for the preserving of high frequency component. The correlation of bands can obtain the feature information, iterative back projection is used to reconstruct every single band image, and these single high resolution images are synthesized to a panchromatic remote sensing image. Experimental results show that the reconstruction effectiveness of the algorithm is good.
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Computer Engineering. 2012, 38(11): 208-210. https://doi.org/10.3969/j.issn.1000-3428.2012.11.064The throughput of the existing implementation of the reconfigurable JH algorithm is relatively small, thus, this paper optimizes the S-box and proposes a new reconfigurable JH hardware implementation. Experimental results show that the proposed design achieves 322.81 MHz clock frequency using 1 405 slices, which has the advantages of less hardware resources, better performance, and lower power consumption than the existing designs.
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Computer Engineering. 2012, 38(11): 211-213,216. https://doi.org/10.3969/j.issn.1000-3428.2012.11.065The captured circular Marks are deformed sometimes during the inspection of defects on the HDI PCB, which may affect the precision of inspection. A new accurate positioning algorithm of circular Mark is proposed by obtaining the center of the most round ellipse. The colorful image of Mark is converted into gray image. The Mark region and its background are separated by using Otus threshold segment technology. The edge points(the outline of image) are obtained by binary images. The outside rectangle of ellipse are obtained by fitting the outlines of the image. The most round ellipse can be confirmed according to the criterion that the ratio of the difference between the length and width of rectangle and the width of the rectangle is less than 0.1. The center of the most round ellipse is output which is the Mark center. Simulation tests show that this algorithm has good characteristics such as speediness, strong anti-interference ability and robustness.
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Computer Engineering. 2012, 38(11): 214-216. https://doi.org/10.3969/j.issn.1000-3428.2012.11.066To resolve the contradiction between positioning accuracy and positioning errors of the existing position methods, this paper proposes an improved localization method. The NanoPAN5375 wireless communication and ranging module is used for platform localization, two points ranging position algorithm and a new error correction algorithm are adopted. The fingerprint database of ranging error is compensated for the value of range, the value of range is corrected through the proportion of area, and the coordinate of the target is solved. Experimental result shows that this method can meet the wireless localization accuracy demand of moving water quality monitoring platform.
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Computer Engineering. 2012, 38(11): 217-220,224. https://doi.org/10.3969/j.issn.1000-3428.2012.11.067As to the problem of Quality of Service(QoS) and congestion in the wireless communication network, the information dissemination management simulation system based on the technology of virtual overlay network is introduced. By analyzing the requirement of mobile communication, this paper simulates typical application environment, and makes great effort to study and explore the information dissemination management technology with OMNeT++ simulation tool. The overlay network is built to implement the key technology of network state awareness, QoS routing calculation and service transmission optimization, which constructs a information dissemination management simulation system. Evaluation result shows that the system can improve the business performance of wireless communication network.
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Computer Engineering. 2012, 38(11): 221-224. https://doi.org/10.3969/j.issn.1000-3428.2012.11.068In order to identify the dumb equipments in industrial Internet of Things(IOT), this paper proposes a topology discovery protocol based on incomplete knowledge of principles. It defines decision rules for dumb equipments based on incomplete knowledge of principles and designs network topology generation algorithm. It searches whole network by breadth-first, and gets numbers and connection condition of dumb equipments. Test result shows that the topology has faster discovery speed and higher recognition rate for dumb equipments.
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Computer Engineering. 2012, 38(11): 225-227,246. https://doi.org/10.3969/j.issn.1000-3428.2012.11.069According to the problem that lots of research on the real-time schedule model and algorithm for multi-core platform has not been realized in the real-time operating system, this paper provides a new method to build a public platform in Linux which is composed by two parts. One is the scheduling mode which can realize the functions of the system call and the scheduling process and synchronizing, the other is the tracing mode which can realize the log and tracing the tasks. Experimental results show that it is feasible to work accurate.
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Computer Engineering. 2012, 38(11): 228-230.250. https://doi.org/10.3969/j.issn.1000-3428.2012.11.070According to the rigorous requirements for real-time performance and conditional resource of the micro-satellite, inference engine of expert system is designed based on fault tree. It designs forward direction inference algorithm based on breadth-first search, and reverse direction inference algorithm based on depth-first search search. Time complexity and space complexity of two algorithms are both linear. Experimental result shows that the engine can not only improve the efficiency of inference engine, but also save the resource of the micro-satellite.
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Computer Engineering. 2012, 38(11): 231-233,253. https://doi.org/10.3969/j.issn.1000-3428.2012.11.071In response to the features of the environment and disaster monitoring and forecasting small satellite(HJ) condition, this paper researches and designs a kind of disaster characteristics information automatic inversion system. According to business requirement of disaster monitoring and early warning, the system adopts B/S architecture and integrates twenty five models of disaster characteristics information automatic inversion, which uses level 2 remote data production of HJ satellite as main input. According to data process relations of these inversion models, a kind of automatic batch process system is designed. Experimental results show it extends HJ star information production chain, and provides real-time information production for disaster monitoring and early-warning. At the same time the system reduces the difficulty of the common users application remote sensing information.
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Computer Engineering. 2012, 38(11): 234-238. https://doi.org/10.3969/j.issn.1000-3428.2012.11.072This paper introduces the concepts of formal design and verification for the Operating System(OS), and elaborates the framework and foundational methods of formal design and verification. It compares and analyzes the monolithic kernel and micro kernel architectures of the OS. Meanwhile, it investigates multiple design and verification projects in depth, focusing on the verification objectives, the methodology, the advantages and limitations, and the progression. It summarizes the state of the art, analyzes and outlooks the trends of the formal design and verification for the OS. What is more, from the aspects of model design, verification tools, code implementation and verification reuse, it advances the ideas of formal design and verification.
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Computer Engineering. 2012, 38(11): 239-241. https://doi.org/10.3969/j.issn.1000-3428.2012.11.073Aiming at the problem of feature performance evaluation for advanced Radar Emitter Signals(RES), the Analytical Hierarchy Process(AHP)-based feature evaluation method of radar emitter signals is put forward. On the basis of the proposed feature evaluation index system of advanced radar emitter signals, this method proposes an AHP-based feature evaluation model of advanced radar emitter signals through the combination of analytical hierarchy process. The model is applied to the radar emitter signal feature assessment practice. Experimental results show that the model can reduce the adverse effects which are brought by uncertain factors and also show that the model can achieve better feature evaluation for advanced RES.
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Computer Engineering. 2012, 38(11): 242-246. https://doi.org/10.3969/j.issn.1000-3428.2012.11.074For the purpose of verification of the memory consistency model after tapeout stage, this paper proposes a low time complexity algorithm by exploring the key time order information which is implicitly derived based on the values of performance counters being scanned periodically. The MOTEC tool which implements this algorithm is general enough to support many multicore processor systems with trivial modifications. The complexity analysis shows that the time complexity of MOTEC is only , thus MOTEC can verify the multicore program of millions of lines.
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Computer Engineering. 2012, 38(11): 247-250. https://doi.org/10.3969/j.issn.1000-3428.2012.11.075A scheme combining data cache with partial replication based on Content Distribution Network(CDN) is proposed in order to find an accelerated scheme appropriate for various Web applications. The scheme adapts to various Web applications dynamically by way of cache coherency strategy based on master-slave protocol model and spatial clustering algorithm using correlation-based similarity. Experimental result shows that this scheme improves not only throughput of system but also users’ experience. Besides, it can also resist flood crowds efficiently.
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Computer Engineering. 2012, 38(11): 251-253. https://doi.org/10.3969/j.issn.1000-3428.2012.11.076In the regional medical information sharing situation, traditional anonymity privacy protection algorithm performs poor resistance when facing with background knowledge attack. So this paper introduces the anonymous sensitive attribute clustering algorithm. The algorithm uses the links between sensitive attributes to make micro-property clustering, it increases the similarity between the sensitive attributes in the equivalent group while remaining the difference between them. The algorithm can perform better resistance while facing background knowledge attack with improved ability to resistant the leakage risks. Experimental results show that the loss of privacy in the data sheet risk reduced substantially when using the algorithm.
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Computer Engineering. 2012, 38(11): 254-257,261. https://doi.org/10.3969/j.issn.1000-3428.2012.11.077In order to find the review spammers, this paper proposes a user review spammer detecting method that is based on users’ behavior. Starting from the purpose of review spammers, it makes spammer’s five behavior patterns as the index of spammer detection. Based on the 1 470 reviewers, it gets from the JOYO Amazon website, according to a single indicator selection and 5 indicators integration selection, finally gets the 25 of most likely spammers and 25 of the most unlikely spammers, and markes artificially the 50 of suspicious reviewers, according to the artificial results trained a supervised linear regression model which is based on the 5 indicators. Experimental results show that the model of the spammer detection finds 88 review spammers in the 1 470 reviewers, and is more effective than those based on user voting usefulness of the baseline method.
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Computer Engineering. 2012, 38(11): 258-261. https://doi.org/10.3969/j.issn.1000-3428.2012.11.078For the current situation that it is difficult to carry out experiments in Wireless Sensor Network(WSN) teaching process, this paper designs a teaching platform for WSN routing experiments based on source-code level. This platform solidifies the generic part of routing algorithms by using modular approach. Users can configure different routing algorithms by parameter configuration. Students can focus on the key algorithm designing and do simulation tests during the routing experiment. Preliminary evaluation results show that most users are able to complete one or more routing algorithms in two class hours as well as simulation tests, which can simplify the simulation experiment and the amount of difficulty.
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Computer Engineering. 2012, 38(11): 262-263,267. https://doi.org/10.3969/j.issn.1000-3428.2012.11.079Traditional centralized anomaly detection methods take a lot of network resources and computing time. Therefore, a distributed anomaly detection method based on model share is proposed. The method firstly employs majority vote, boundary extension, average stack and weighted distance to obtain all local models, and then exchanges local data mining models to realize data sharing, so that the overall integrated learning model is established. Experimental results show that the proposed method can detect anomaly from the global view, reduce test data transmission of overall integrated learning model and effectively protect data privacy.
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Computer Engineering. 2012, 38(11): 264-267. https://doi.org/10.3969/j.issn.1000-3428.2012.11.080This paper proposes a water quality evaluation method based on J48 decision tree algorithm. By analyzing the common methods of water quality evaluation such as K nearest neighbor, Bayesian classification, vector space model, based on the water quality monitoring data of the region in 2008, it calculates the water quality of one region by using J48 decision tree algorithm and single-factor pollution index. A model is set up after classifying dates, cleaning up attributes and choosing parameters of J48 decision tree. Experimental result shows that the validation rate of J48 decision tree algorithm is about 95%. It shows that this method which this paper chooses has a good classifying assessment effect.
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Computer Engineering. 2012, 38(11): 268-270,273. https://doi.org/10.3969/j.issn.1000-3428.2012.11.081In order to solve the problem of reliability and security for the two-way data transmission between sensor and data center, this paper presents a remote real-time health monitor system. It designs the system architecture which includes micro physiological information terminal data transmission system and real-time service support platform. It uses Bluetooth, GPRS technologies and smart phones as medium to realize two-way transmission of data, and enhances the data transmission quality by using IOCP protocol, dynamic encryption key, data validation, anti-malware attacks. Experimental results show that the system has good reliability and security.
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Computer Engineering. 2012, 38(11): 271-273. https://doi.org/10.3969/j.issn.1000-3428.2012.11.082Traditional physiology human fatigue detection methods have the problems that the time is long and accuracy is low. Aiming at this problem, this paper proposes a novel method for human fatigue identification based on gait acceleration. Collecting gait acceleration data by using a Micro Electro Mechanical Sensor(MEMS) triaxial accelerometer, based on correlation coefficients, the method proposed in this paper can be used to identify human fatigue. Experimental results show that the accuracy of identification is 93.06% with 9 test subjects, and this method has the advantages of calculating time and accuracy.
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Computer Engineering. 2012, 38(11): 274-276,280. https://doi.org/10.3969/j.issn.1000-3428.2012.11.083According to answers’ keywords, sentence grammar semantic informations and adjusting rules, this paper proposes a two level similarity computation algorithm which integrates the advantage of word level and sentence level similarity computation. It focuses on questions of text descriptive subjective examinations complexities and machine marking difficulties. Experimental results show that the system can obtain the minimum invalid marking ratio and fast speed, while word level coefficient α value is about 0.7. This algorithm complies with the effect of manual marking better.
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Computer Engineering. 2012, 38(11): 277-280. https://doi.org/10.3969/j.issn.1000-3428.2012.11.084This paper proposes a novel electronic commerce evaluation model combined with subjective trust factor and objective risk factor. The model synthesizes trust and risk to acquire the acceptable extent which is used to decide whether bargain or not. This new model gives full consideration to subjective and objective factors that affect trading process, which can improve the accuracy of decision-making, and prevent attacks of malicious entities effectively. Experimental results show that the new electronic commerce evaluation model can effectively improve the security of making online trade.
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Computer Engineering. 2012, 38(11): 281-283,286. https://doi.org/10.3969/j.issn.1000-3428.2012.11.085This paper presents an efficient parallel architecture for fast solving linear system of equations over binary operations of GF(2), which is derived from a proposed hardware-optimized Gaussian elimination. The optimization of the Gaussian elimination with pivot element is realized by using parallel elimination and cyclic shift operations instead of loop nest in each iteration. A mesh structure of “smart memory” cells is proposed for building the whole parallel architecture where the modified algorithm is mapped onto. The average running time of the architecture for n-dimension binary matrix equals 2n cycles as opposed to about 1/4n3 in software. Experimental results show that the performance of the system is improved by about two orders of magnitude.
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Computer Engineering. 2012, 38(11): 284-286. https://doi.org/10.3969/j.issn.1000-3428.2012.11.086Deep Web has rich, high-quality information resources. Because it does not have a static page links which is directly point to the Deep Web, most current search engines can not find these pages, but they can submit a query by filling out the form to obtain. This paper proposes a crawling strategy of Deep Web crawler. A hierarchical classification with the results of Web links guides the information extractor to extract the link. The strategy limits the crawling depth in three, extracts from the nearest link to the query form, and only extracts the links belonging to these three levels. Thus it reduces the reptiles crawling time, and improves the accuracy of reptiles. At the same time, it designs the Deep Web data sources for focused crawling algorithm. Experimental results show that this strategy can effectively download Deep Web pages to improve crawling efficiency.
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Computer Engineering. 2012, 38(11): 287-289. https://doi.org/10.3969/j.issn.1000-3428.2012.11.087This paper describes the application of Virtual electrical and electronic network laboratory named iEEVL(Internet-based Electrical Engineering Virtual Lab) based on Modelica for unified modeling. In iEEVL, experiments for six courses including circuit theory, analog electronic technique, digital electronic technique, micro-electronics, Micro Control Unit(MCU) and Digital Signal Processing(DSP) are implemented. Modelica is used for unified modeling. Details about using Modelica for modeling are discussed. The lab enables users to design their own circuit and get simulation result simultaneously. Teachers may design new component with Modelica and add to the lab for students’ use.
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Computer Engineering. 2012, 38(11): 290-292. https://doi.org/10.3969/j.issn.1000-3428.2012.11.088For the current controller’s shortage in openness and real-time, this paper addresses an architecture of industrial robot controller which communicates by EtherCAT protocol. In order to meet the high-reliability and real-time requirements, the controller uses the embedded microprocessor Advanced RISC Machine(ARM) as the core hardware, and it uses hierarchical structure of component to design the software based on μC/OS-II, which can improve reusability. Test results show that the controller system has strong real-time performance and easy-expansibility.
2024
Volume 50 No 3
Volume 50 No 3
(Started in 1975, Monthly)
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428