05 December 2012, Volume 38 Issue 23
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Computer Engineering. 2012, 38(23): 1-6. https://doi.org/10.3969/j.issn.1000-3428.2012.23.001
To detect user’s privacy leakage in Android software, this paper proposes an automated detection system based on dynamic taint tracking, called TaintChaser. TaintChaser can detect behaviors of user’s data leakage in Android applications under test at a fine granularity, and the system also can analyze and test massive Android software in the automatic way. It uses TaintChaser to automatically analyze 28 369 popular Android applications and finds that 24.69% of them may leak user’s privacy.
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Computer Engineering. 2012, 38(23): 7-9,14. https://doi.org/10.3969/j.issn.1000-3428.2012.23.002
In wireless video transmission system, the length of the frame changes and the source bit rate varies during the transmission. To reduce the system delay, this paper proposes a low delay wireless cooperative video transmission system with relays. The system delay is formulated and the reason of the delay reduction is analyzed. To improve the quality of the video transmission, a relay strategy and modulation and coding scheme are introduced for the system. The simulation results demonstrate that the transmission system can effectively reduce the video transmission delay and the Bit Error Rate(BER).
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Computer Engineering. 2012, 38(23): 10-14. https://doi.org/10.3969/j.issn.1000-3428.2012.23.003
In order to solve the problem that recent researches on detection of Session Initiation Protocol(SIP) flooding attacks in IP Multimedia Subsystem(IMS) can not adapt the network environment, this paper puts forward a self-adaptive detection method for SIP flooding attacks based on extended state machine. It builds the extended SIP state machine according to adding a state which described that the network is being attacked or abnormal, then adaptive adjusts the threshold through the introduction of adaptive algorithm based on Kalman filtering. Experimental results prove that this method has better detection performance than detection methods using fixed threshold, and it is more available in the real network.
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Computer Engineering. 2012, 38(23): 15-18,23. https://doi.org/10.3969/j.issn.1000-3428.2012.23.004
Remote sensing images have large spatial sizes, and large amount of system resources are occupied during browsing. To deal with these issues, so that arbitrary times of undo and redo operations can be done, and solve problems, such as the system supported less file formats or data types and the high complexity in the conversion of file formats and data types, this paper puts forward a mechanism which selectively builds and updates the cache with multiple threads and uses the path bracket method on image display. The method of combining structure array with stack objects is adopted, and the software system development is based on Geospatial Data Abstraction Library(GDAL). Test results show that the system has good stability and robustness, especially when displaying files with larger spatial sizes in RGB mode, zooming and roaming operate flexibly and respond quickly, which meet the engineering requirements and actual needs.
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Computer Engineering. 2012, 38(23): 19-23. https://doi.org/10.3969/j.issn.1000-3428.2012.23.005
Most public key encryption schemes are unsecure, if a polynomial time adversary can get ciphertexts that are dependent on the secret key. In order to defend the attacks, this paper gives an instance of the general subgroup indistinguishability assumption——elliptic curve subgroup indistinguishability assumption and a reduction algorithm. It is the first to construct a public key scheme based on elliptic curves over ring and reduce the indistinguishability of the ciphertexts to elliptic curve subgroup indistinguishability assumption. The scheme is proved secure under the assumption.
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Computer Engineering. 2012, 38(23): 24-27,32. https://doi.org/10.3969/j.issn.1000-3428.2012.23.006
In order to implement functions of the dual quaternion strapdown inertial navigation system, it is necessary to design dual quaternion update algorithms suitable for a navigation computer to execute. The optimization design of dual quaternion update algorithms by using screw vectors as the tool is presented in this paper. The solution of a screw vector is given and the typical sculling motion is chosen as the appropriate test condition by analysis. Then, as an example, the two-sample screw vector optimization algorithm for updating dual quaternions is derived. The presented dual optimization algorithm is compared with the conventional optimization algorithm for compensating sculling errors in the performance. It is shown that the dual optimization algorithm has the absolute superiority. It not only describes rotation and translation in a unified form, but also attains the optimal precision identically when estimating two kinds of motion parameters.
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Computer Engineering. 2012, 38(23): 28-32. https://doi.org/10.3969/j.issn.1000-3428.2012.23.007
Implicit flow has a major impact on the accuracy of the taint analysis. In this paper, a method for implicit flow detection is proposed, which is based on the Static Single Assignment(SSA) form of program, including detecting control dependencies relationship by generating dominate tree on control flow graph, finding re-convergence point by computing dominance frontier, acquiring values by inserting virtual function at re-convergence point in SSA, and marking the correct taint type of variables. Compared with the manual auditing results, test results show that this method can diagnose the undertainting and overtainting problem of two analysis tools, and reduce false-positive and false-negative rate of implicit flow effectively.
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Computer Engineering. 2012, 38(23): 33-36. https://doi.org/10.3969/j.issn.1000-3428.2012.23.008An overall framework is put forward to expand the real-time ability of the middleware Satellite Data Model(SDM) based on publish/ subscribe model. A linear and dynamic method is presented to map middleware priority to native operating system. It analyzes the schedulability test of scheduling hard real-time period and sporadic tasks under static priority preemptive scheduling algorithm whose priority is assigned freely. To improve its fault-tolerance capability, the software by Recovery Block(RB) technique is done back up so that it can avoid the breakdown of any part one. Compared with the preceding system, this service framework possibly meets the needs of distributed real-time applications.
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Computer Engineering. 2012, 38(23): 37-41,46. https://doi.org/10.3969/j.issn.1000-3428.2012.23.009Aiming at the defects of partition quality and mapping efficiency existed in large-scale ontology mapping, this paper proposes a new method for large-scale ontology partition and mapping based on bigraph graph model. A weighted bigraph is built by the similarity between the concepts of two ontologies and the bigraph is partitioned into subgraphs to achieve ontology co-partition. Then the ontology mapping problem is translated into an optimal matching problem in sub-graphs. It applies the revised rules to obtain alignments in the optimal matching. Experimental results show that partition quality and mapping efficiency of this method is well.
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Computer Engineering. 2012, 38(23): 42-46. https://doi.org/10.3969/j.issn.1000-3428.2012.23.010In a general view, some software fields are merged into Software Architecture(SA), such as UML, aspect-oriented programming, service-oriented architecture and component-based software engineering. Considering their relationship, commonality and uniqueness, a classification framework is proposed. Several directions are addressed for further research: investigation of the relationship between SA and the fields, exploration of the mechanisms of dynamic SA, design of ADLs toward specific domains, establishment of the theoretical foundation of SA, and development of supporting tools.
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Computer Engineering. 2012, 38(23): 47-50. https://doi.org/10.3969/j.issn.1000-3428.2012.23.011In order to solve the problems of target data updated in real time and the quality of data source itself in the process of heterogeneous data integration, on the basis of the adapter, the XML and reverse data cleaning technology, a real-time heterogeneous data integration model based on reverse data cleaning is presented. It processes heterogeneous data in major two ways. On the one hand, it uses real-time threads to extract, clean and save the original data that is newly increased or modified. On the other hand, it uses the reverse cleaning process reverse to fix errors and missing in the original data by the valid data in platform or integration. Experimental result shows that the model can improve the data quality of the target data and the original data simultaneously.
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Computer Engineering. 2012, 38(23): 51-56. https://doi.org/10.3969/j.issn.1000-3428.2012.23.012In order to further shorten the UnionPay online transaction system failure recovery time, this paper puts forward to use six Sigma DMAIC methods, including the use of statistical analysis and quality management method and combining the actual production run, proposes effective analysis method for system fault, establishes sustained and effective improvement mechanism about the online transaction high availability. Test results show that this system failure recovery time in 60 seconds is increased from 88% to 93%.
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Computer Engineering. 2012, 38(23): 57-59. https://doi.org/10.3969/j.issn.1000-3428.2012.23.013In the construction of topic oriented information extraction system, extraction requirements are core of all extraction tasks. For natural language description of extraction requirements leads to a computational resource waste and extraction efficiency issues, a formal definition is proposed on the requirements of topic-oriented information extraction. On this basis, it researches on extracting relations between requirements. The reduced requirements set splitting method structural equivalences reduced requirements set, eliminate the extraction redundancy between requirements. Experimental results prove the equivalence of reduced requirements set can improve operating efficiency of the extraction tasks.
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Computer Engineering. 2012, 38(23): 60-62. https://doi.org/10.3969/j.issn.1000-3428.2012.23.014In traditional research of social network, a challenge is that there are few attentions which are paid to users’ relationship representation. To solve this problem, trust is introduced in this paper to describe the relationships among users. A description method of trust chain formal model is proposed, and the model is classified into two types: meta-trust chain and combined trust chain. Moreover, trust degree computation method of Trust Chain Formal Model(TCFM) and the computation operators between trust chains are presented. Example verifies the model in this paper is effective.
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Computer Engineering. 2012, 38(23): 63-66. https://doi.org/10.3969/j.issn.1000-3428.2012.23.015Existing collaborative filtering algorithms can not promptly reflect the change of users’ interest. For this reason, this paper introduces the human brain’s characteristics of memory and forgetting to personalized recommendation, and proposes a collaborative filtering algorithm based on memory. The effective use of short-term memory reflects users’ recent interest. Long-term memory emphasizes the importance of users’ early interest. At the same time, it combines the short-term memory with the long-term memory and proposes the reconciled memory, which makes the recommender system adaptively track the change of users’ interest. Experimental results show that the proposed algorithm has high quality of precision and rapid convergence rate and that it overcomes the low efficiency of CF, SCF, AUICF algorithms to some extent.
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Computer Engineering. 2012, 38(23): 67-70. https://doi.org/10.3969/j.issn.1000-3428.2012.23.016In order to suppress narrowband interference in navigation signal, an improved method based on frequency-domain Least Mean Square(LMS) is proposed. By using the weight leakage factor, the method can reduce the loss of the desired signal in filter process. Meanwhile, with the judgment of the weight coefficient stability, the method can effectively suppress variable frequency narrowband interference. Simulation results show that the proposed method has the effectiveness in suppressing the narrowband interferences of both fixed and variable frequency, it can greatly improve the anti-jamming performance of the navigation receiver.
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Computer Engineering. 2012, 38(23): 71-74,78. https://doi.org/10.3969/j.issn.1000-3428.2012.23.017The existing attractive evolving models have a lower cluster coefficient and ignore the factors which delay the growth of networks. So the new online social network evolving model with damping factors is proposed in this paper. Based on the BA model, the damping factors and their function which considers the attractive factors are researched. In this model, by dividing the damping factors into the recession of initial factors, the loss of nodes’ heat and the inevitable factors, the problems of BA model and CALW model are solved. And by introducing the triangle forming mechanism, the cluster coefficient of the existing attractive evolving model is improved. In order to verify the correctness and validity of proposed model, the mean field theory and Matlab are applied, which are separately to analyze the degree distribution of proposed model and describe the degree distribution.
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Computer Engineering. 2012, 38(23): 75-78. https://doi.org/10.3969/j.issn.1000-3428.2012.23.018Aiming at the problem that each frame cannot switch the system between DFT-S-OFDM and N×SC-FDMA in real-time adaptive transmission of LTE-A’s uplink, a hybrid Adaptive Modulation and Coding(AMC) method is proposed. According to SINR, the method predicts the throughput of DFT-OFDM and N×SC-FDMA in the situation of adaptive transmission, and chooses the system which has greater throughput and the corresponding MCS for the next frame. This method obtains the hybrid performance of spectrum efficiency of DFT-OFDM and N×SC-FDMA in adaptive transmission. Simulation results show that this method can get 1 dB gain in the aspect of throughput performance, compared with the single adaptive transmission system.
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Computer Engineering. 2012, 38(23): 79-83,87. https://doi.org/10.3969/j.issn.1000-3428.2012.23.019An efficient routing algorithm based on utility and erasure coding is proposed to solve how to efficiently transfer large files(such as audio, video files) in opportunistic networks. The algorithm encodes the source file by encoding algorithms into small chunks, and on the select of the next hop node, taking forwarding mechanism based on utility value, constantly looking forward a strong node to take the forwarding task until the data is routed to the destination node. Theoretical analysis and simulation results show that UH-EC(utility-encoding hybird scheme) outperforms the classic H-EC routing algorithm, effectively reduces network overhead, group of end-to-end delay, and the effects of black hole nodes for file transferring rate.
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Computer Engineering. 2012, 38(23): 84-87. https://doi.org/10.3969/j.issn.1000-3428.2012.23.020For the too much energy consumption issue in the commonly used periodical broadcasting metadata packages to determine whether code dissemination is needed in Wireless Sensor Networks(WSN), a low energy consumption code dissemination protocol is proposed. That is whether code dissemination is necessary can be determined when the sensor node is under normal communication. Simulation result shows that the protocol can reduce the energy consumption, compared with now code dissemination protocols.
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Computer Engineering. 2012, 38(23): 88-91. https://doi.org/10.3969/j.issn.1000-3428.2012.23.021In order to reduce the average energy consumption of a cluster in Wireless Sensor Network(WSN) clustering routing protocol, and solve the problem of unbalanced energy consumption of cluster-head near the sink node, this paper presents a new algorithm called Balanced Energy Efficient Routing Algorithm(BEERA). It contains constructing the energy consumption model and providing the routing algorithms of BEERA, discusses a series of key issues such as how to calculate the best competitive radius, select the cluster-heads, establish forwarding path among the clusters and generate the clusters. Simulation results show that BEERA prolongs the WSN lifetime effectively compared with Leach and other protocols. It has higher feasibility and stability with the duration of stable period achieved by 19.6%~129% and the turns number improved by 22.8%~58.6% when entering into HRD phase.
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Computer Engineering. 2012, 38(23): 92-94,100. https://doi.org/10.3969/j.issn.1000-3428.2012.23.022Aiming at problem of the low probability of detection in low Signal Noice Rate(SNR) and high computation complex for traditional cyclic spectrum in the node of Wireless Cognitive Sensor Network(WCSN), a frequency-domain simplified single cyclostationary detection algorithm is adopted. A closed expression of false alarm probability is obtained, and the expression of direct relationship between detection probability and SNR in actual wireless environment is found out. Theoretical studies and simulation results show that the complexity of this algorithm is much lower than traditional cyclostationary detection, and as same as energy detection, so the algorithm can meet the performance of spectrum sensing in WCSN.
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Computer Engineering. 2012, 38(23): 95-100. https://doi.org/10.3969/j.issn.1000-3428.2012.23.023According to the complexity of obtaining d-minimal cuts(paths) and inclusion-exclusion for calculating exact multistate networks reliability, a direct, exact algorithm for solving multistate networks reliability without requiring a priori d-minimal cuts(paths) is presented. The proposed algorithm generates the invalid state spaces based on dividing state spaces according to given rules, obtains the exact multistate networks reliability by iteration. Moreover, the algorithm defines edge capability lower boundary and residual network. Example analysis shows the algorithm can reduce calculation burden, avoid the solution complexity of d-minimal cuts(paths).
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Computer Engineering. 2012, 38(23): 101-103,108. https://doi.org/10.3969/j.issn.1000-3428.2012.23.024Aiming at the problem of cognitive user package lost caused by primary user burst interference in cognitive Orthogonal Frequency Division Multiplexing(OFDM), an efficient anti-jamming piecewise coding scheme based on cognitive OFDM is proposed. The construction of piecewise coding is presented with low redundancy optimization method. Anti-jamming piecewise coding can recover the lost packets by implementing different number of parity check blocks, thus it can protect Secondary Users(SU) from Primary Users(PU) by burst interference avoiding. Simulation results prove that by non-uniform sub-channel selection, anti-jamming piecewise coding with smaller overhead provides better Frame Error Rate(FER) and throughput performance than anti-jamming rateless coding in low jamming rate region.
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Computer Engineering. 2012, 38(23): 104-108. https://doi.org/10.3969/j.issn.1000-3428.2012.23.025Aiming at the disadvantages of Low Energy Adaptive Clustering Hierarchy(LEACH) algorithm that cluster head selection is random, without considering the residual energy and the location of node, this paper proposes an algorithm called Energy-based Affinity Propagation Clustering(EBAPC) topology control algorithm, which is based on energy affinity propagation clustering. In EBAPC algorithm, a new definition called fitness factor is presented, and the cluster center selection strategy in affinity propagation clustering algorithm is borrowed. Experimental results show that in EBAPC algorithm, the cluster head selection is better reasonable, and extends the network lifetime compared with LEACH algorithm.
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Computer Engineering. 2012, 38(23): 109-111,122. https://doi.org/10.3969/j.issn.1000-3428.2012.23.026Aiming at the characteristics of bandwidth constrained and topology variation in Ad hoc wireless network, a new Dimidiate Cycle Iteration(DCIA) topology inference algorithm based on Prüfer code and network traffic is proposed. Path distance matrix called POD is constructed by acquiring the value of TTL in TCP packets in tree network, and the inner topology structure topology is inferred with the proposed algorithm. Simulation experiments show that the proposed algorithm’s correctness ratio on inference topology is up to 100 percent, and possess high dependability.
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Computer Engineering. 2012, 38(23): 112-114. https://doi.org/10.3969/j.issn.1000-3428.2012.23.027The problems of packet delay, disorder and long recover time are widespread in traditional Multi-protocol Label Switching(MPLS) fast re-routing fault-recovery model. In order to solve the problems, a fast re-router fault-recovery synthetic model based on MPLS through expanding the MPLS message is presented. In this model, the LDP message is expanded, combined with global strategy and local strategy, and a new method to establish temporary path is put forward. The conclusion that this multiple model shows better performance on reducing fault-recover time is proved by OPNET network simulation.
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Computer Engineering. 2012, 38(23): 115-117. https://doi.org/10.3969/j.issn.1000-3428.2012.23.028Current image encryption algorithms are not resistant to plaintext-chosen attack. In order to solve the question, a new image encryption algorithm based on adaptive parameters is proposed. The improved image barycentric coordinates are chosen as adaptive parameters. The adaptive parameters and user keys are input into four-dimensional hyperchaotic system to generate chaotic sequences to encrypt image. And the adaptive parameters are saved into encrypted image by reversible watermarking technology. Experimental results show that the algorithm is expediently to manage keys and can resist some attacks such as chosen-plaintext attack.
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Computer Engineering. 2012, 38(23): 118-122. https://doi.org/10.3969/j.issn.1000-3428.2012.23.029This paper introduces a practice-oriented PKU VANETs privacy-preserving system which aims to the prior location and identity privacy protecting. It proposes the architecture of PKU-VPPS and does some close analysis about that. The proposed system is based on the key technologies such as TP4RS protocol, TC-TPS protocol, VLSP protocol, not only can provide good identity and location privacy protecting for the vehicles, but also can be implemented and deployed well because of its practice-based design and expandability.
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Computer Engineering. 2012, 38(23): 123-126. https://doi.org/10.3969/j.issn.1000-3428.2012.23.030In Delay Tolerant Network(DTN), reputation-based routing schemes often meet the trouble of outdated reputation. The reputation maintained by a node is usually out of date because of the long delivery delay. To achieve the goal that predict nodes’ reputation accurately according to history of reputation, this paper proposes a reputation evaluation policy based on Markov chain. It collects the reputation of the target node from its neighbors, calculates a state transition matrix with the collected reputation, uses the state transition matrix and the latest reputation to predict the reputation of the target node, and evaluates target node’s reputation through probability theory. Experimental results show that in comparison with existing reputation-based schemes, this scheme can weaken the negative effect of delay and predict the reputation of the target node accurately, so it is more robust against bad-mouthing attack.
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Computer Engineering. 2012, 38(23): 127-130,136. https://doi.org/10.3969/j.issn.1000-3428.2012.23.031Kerberos authentication protocol is apt to suffer password attack and replay attack, and it needs double bilinear logarithmic operations, double exponent arithmetic and one dot multiplication on elliptic curve. Aiming at vulnerability and large amount of computation of Kerberos authentication protocol, this paper improves it with the help of high-efficient certificateless key agreement. In order to resist masquerade attacks, the certificateless signcryption technology is used between a user and authentication service. Analysis result proves that the improved protocol meets six basic security demands of key agreement. That’s to say, it can satisfy with the requirements of known key security, perfect forward security, resisting unknown key sharing security, keys’ uncontrollability and temporal known session information security. It can resist password attack, replay attack, intermediary attack and key exposure impersonation attack, and has higher efficiency with only three dot multiplications.
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Computer Engineering. 2012, 38(23): 131-136. https://doi.org/10.3969/j.issn.1000-3428.2012.23.032Most methods of root cause analysis often require manual intervention, and the classification results of anomaly events are not satisfied. This paper proposes a novel model named Traffic Anomaly Classification based on Hierarchical Clustering(TAC-HC). It utilizes the learning process of its feature attributes to establish classification tree gradually and the similar anomaly is embedded in the subtree. The classification tree classifies new anomalies with the number of clusters unknown. Experimental results show that the classification accuracy of TAC-HC algorithm reaches 89%, and the classification accuracy of anomalies with low traffic volumes such as network scan reaches 95.3%.
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Computer Engineering. 2012, 38(23): 137-138,142. https://doi.org/10.3969/j.issn.1000-3428.2012.23.033Threshold cryptographic scheme based on bilinear pairings depends too much on the bilinear pairing tool, but the computation of the bilinear pairing is very time-consuming so that the efficiency of secret sharing scheme is affected badly. By using Shamir threshold sharing scheme, this paper proposes a new method which threshold shares in the bilinear group. Its based-identity private key can be shared through the secret sharing scheme for integers. Analysis result shows that the new method needs only two times bilinear pairing computations and can be used to further design efficient identity based threshold cryptographic schemes.
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Computer Engineering. 2012, 38(23): 139-142. https://doi.org/10.3969/j.issn.1000-3428.2012.23.034Aiming at the problems of lacking credibility evaluation for the feedback information and risk assessment in trust model based on cloud theory, this paper proposes a new trust model. The credibility of an evaluation is measured by combining the evaluation number and evaluation consistency about a feedback entity. Trust cloud for an entity is generated based on the weighted backward cloud generator algorithm. Risk value is assessed according to entity’s active degree and the numerical characteristics of the entity’s trust cloud. Simulation results indicate that the model can reflect the behavior characteristics of every entity accurately, and the success rate of interaction between entities is significantly improved.
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Computer Engineering. 2012, 38(23): 143-145. https://doi.org/10.3969/j.issn.1000-3428.2012.23.035This paper analyzes the self-certified multi-receiver signcryption scheme proposed by Wang Zhicang et al, and points out that attackers can forge new legal messages by public information, so that their scheme does not have the characteristic of unforgeability. Based on the discrete logarithm problem in finite field, this paper proposes an improved scheme by inserting the sender’s private data into the encrypted session. Analysis result proves that the improved scheme can resist forgery attack, and has the characteristics of non-repudiation and confidentiality.
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Computer Engineering. 2012, 38(23): 146-149. https://doi.org/10.3969/j.issn.1000-3428.2012.23.036Most existing domestic e-commerce platforms use eBay trust model, whose sellers’ reputation scores are the sum of feedback ratings offered by buyers. All these models do not distinguish between the rationality of buyers’ feedback ratings and their reference value. This paper proposes a group-based Customer to Customer(C2C) e-commerce trust model, by calculating buyers’ familiarities with sellers to determine the credibility of the buyers, considering transaction price, trading hours and other factors that may impact on the credibility. Through this method, a more comprehensive and effective C2C e-commerce trust model is built. Simulation results prove that the model can provide buyers with more comprehensive and accurate reputation information of sellers than Sporas trust model.
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Computer Engineering. 2012, 38(23): 150-153. https://doi.org/10.3969/j.issn.1000-3428.2012.23.037In order to decrease the computation complexity and the transmission quantity between delegator and worker, meanwhile increasing the rate , this paper constructs a more efficient non-interactive delegation of computation by using verifiable fully homomorphic encryption scheme. Analysis result shows that the scheme satisfies the soundness and completeness of delegation of computation scheme. In the scheme, the delegator’s complexity is , worker’s complexity is , and transmission complexity is . Compared with other delegation of computation schemes, its verification process is more simple, and the rate ≥1/2.
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Computer Engineering. 2012, 38(23): 154-157. https://doi.org/10.3969/j.issn.1000-3428.2012.23.038In order to improve the identification accuracy of Web data table, this paper proposes an identification method based on Support Vector Machine(SVM) and mixed kernel function. This paper gives the structural features, content features and row(column) similarity features of the table, and takes mixed kernel function constructed by a polynomial kernel function and a linear kernel function, automatically recognizes the Web meaningful tables. Experimental result shows that the average precision rate and recall rate of this method are 95.14% and 95.69% in seven sites.
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Computer Engineering. 2012, 38(23): 158-161,165. https://doi.org/10.3969/j.issn.1000-3428.2012.23.039In order to realize service robot flexibly self-location and accurately grasping objects, this paper proposes a self-location and grasping algorithm based on vision and Radio Frequency Identification(RFID). It gives the grid environment, uses RFID to determine the initial position, route and direction of the robot. This paper uses visual system to get the space coordinates of objects, converts them to arm coordinate system, models with the improved D-H model for arm, and gives manipulator inverse solution graping algorithm. Experimental results show that this algorithm can make the robot location success rate reach 76.7%, and graping success rate is 90%.
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Computer Engineering. 2012, 38(23): 162-165. https://doi.org/10.3969/j.issn.1000-3428.2012.23.040A Chinese Blog topic classification method based on approximate minimum enclosing ball is proposed. By transforming the optimization problem of the Support Vector Machine(SVM) to the optimization problem of approximate minimum enclosing ball equivalently, the Blog topic classifier can be trained quickly by only selecting a core subset of the original large scale dataset. The feature selection experiments and topic classification experiments are executed on large scale Blog dataset. Experimental results show that the method can provide good classification precise and quick run-time speed.
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Computer Engineering. 2012, 38(23): 166-168,172. https://doi.org/10.3969/j.issn.1000-3428.2012.23.041A new method of in-pulse modulation recognition is proposed to meet the in-pulse analysis’ needs under the complex electromagnetic environment. The wavelet ridge is extracted by Morlet wavelet transform. The time-frequency curve is gotten according to the relation between instantaneous frequency and optimal scale. The pulse modulation is recognized by analyzing its shape. The new idea includes creating the time-frequency resolution adjustment function, optimizing the wavelet ridge extraction process and proposing the recognition algorithm based on the curve’s shape. It improves the accuracy and reduces the calculation. Simulation result shows that, when Signal-to-Noise Ratio(SNR) is 3 dB, the lowest rate of recognition accuracy can reach 98%, when SNR is 1 dB, it can also reach 70%.
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Computer Engineering. 2012, 38(23): 169-172. https://doi.org/10.3969/j.issn.1000-3428.2012.23.042In order to overcome the problems that the traditional clustering algorithm is sensitive to the initial parameter in the key frame extraction process, an efficient algorithm for key frame extraction based on improved K-means algorithm is proposed in this paper. In the implementation of the Artificial Fish Swarm Algorithm(AFSA) clustering algorithm, the artificial fish implement self-organization clustering under the guidance of group similarity and ultimately the artificial fish gathered in several extreme points, according to the greatest progress principle. The artificial fish with the biggest group similarity in each extreme point is set as the initialized cluster center. This paper implements K-means algorithm to obtain the final clustering result and extracts key frame. Experimental result shows that the accuracy of this algorithm is high, and can well express the main content of the video.
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Computer Engineering. 2012, 38(23): 173-176,180. https://doi.org/10.3969/j.issn.1000-3428.2012.23.043Aiming at the Levenberg-Marquardt Back Propagation(LMBP) algorithm of neural network sometimes converges to the saddle point during training process, an improved LMBP algorithm which can overcome the saddle point effectively is proposed. All eigenvectors for all the positive eigenvalue of Jacobi matrix are calculated as new searching directions. The improved LMBP algorithm is proved that it can get out of saddle point, and it iterates to minima effectively by an example of comparing with the traditional LMBP algorithm and the improved one.
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Computer Engineering. 2012, 38(23): 177-180. https://doi.org/10.3969/j.issn.1000-3428.2012.23.044Speech recognition based on traditional spectral feature is liable to be influenced by the acoustic conditions of the environment. Articulatory Feature(AF) is robust to such conditions. In this paper, the rules of phonetic mapping to AF of Mandarin and Uighur speech are derived. The neural networks are trained to obtain posterior probability of AF. The features are combined with Mel Frequency Cepstral Coefficient(MFCC) and are used to train the hidden Markov based acoustic model. Experimental results show that by combining the MFCC with the feature of voicing or aspiration in Mandarin, the feature of voicing or manner in Uighur, significant error reductions can be obtained.
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Computer Engineering. 2012, 38(23): 181-184,189. https://doi.org/10.3969/j.issn.1000-3428.2012.23.045While solving the large-scale graph-coloring problems, the existing distributed algorithms require that the node must be connectable. The growth of the neighbor-nodes brings negative effect on both algorithm efficiency and the solvable scale. So a new algorithm is proposed. The graph-coloring problem is converted to the game problem on the multi-Agent platform. Using the adaptive learning algorithm, each Agent optimizes its own state to maximize system’s utility which is the Nash equilibrium. Empirical evaluation shows that the new method has higher efficiency, better immunity to the growth of neighbors and can deal with larger scale problems than existing distributed algorithms.
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Computer Engineering. 2012, 38(23): 185-189. https://doi.org/10.3969/j.issn.1000-3428.2012.23.046This paper proposes a novel algorithm of packets matching by combining improved differential evolutionary algorithm with classic packets matching algorithm. The time performance of the algorithm in packet matching is very weakly correlated with the number of the rules, thus the algorithm is very suitable for solving packet matching, which is multi-dimensional and large-scale problems. Numerical analysis and experimental results show that this new algorithm effectively improves the wire-speed forwarding, compared with the traditional algorithm based on Trie tree.
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Computer Engineering. 2012, 38(23): 190-193,197. https://doi.org/10.3969/j.issn.1000-3428.2012.23.047Existing ant colony algorithm is easy precocious and easy to fall into local optimum when the Subset Traveling Salesman Problem (STSP) is solved through it. In order to solve this problem, the crowding factor is embedding into the state transition and the pheromone update according to the characteristic of the STSP. It makes its global searching ability enhance remarkably. An efficient neighborhood searching technique and a simple and effective local mutation technique are introduced into this algorithm to improve further the quality of solution. Experimental results show that the improved algorithm has much higher quality and stability than that of existing ant colony algorithm.
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Computer Engineering. 2012, 38(23): 194-197. https://doi.org/10.3969/j.issn.1000-3428.2012.23.048There is the drift phenomenon in video target tracking, and learning algorithm needs offline training. In order to solve this problem, a online multiple sample video target tracking method for separation of detection, recognition and tracking is proposed. In this method, multiple sample approach tries to resolve the inherent ambiguities of many practical learning in the process of update instance. And the beyond semi-supervised learning tends to settle the “drifting” problem. Experimental results show that this method is more robust, can effectively solve the “drifting” problem, and track the target real-time online.
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Computer Engineering. 2012, 38(23): 198-202. https://doi.org/10.3969/j.issn.1000-3428.2012.23.049In 3D reconstruction, point cloud registration time of different camera coordinate system is too long. In order to sovle this problem, this paper proposes a real-time 3D point cloud data registration algorithm based on Graphic Processing Unit(GPU). The projection mapping method is used to find corresponding point pairs, the transformation matrix is obtained by minimizing the distance from the point to the tangent plane, and uses the GPU to multi-thread and parallelly process mass image data. Experimental results show that, in order to keep original registration effect, the optimal time-consuming of this algorithm is about 11.9% compared with Iterative Closest Point algorithm based on GPU(ICP-GPU) in containing 307 200 data 2 frame point cloud.
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Computer Engineering. 2012, 38(23): 203-205. https://doi.org/10.3969/j.issn.1000-3428.2012.23.050According to the center of gravity location changing in robot obstacle negotiation, a kind of master-slave tracked compound robot obstacle negotiation research method is put forward in this paper. The robot prototype model is given. The researches of prototype focus variation and main crawler system chain wheel load torque variation, and simulation analysis of obstacle and stairs are preceded. Simulation result shows that the change of gravity is a key factor in obstacle and climbing the stairs. There is a maximum wheel torque when the prototype crawler system changes.
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Computer Engineering. 2012, 38(23): 206-210,218. https://doi.org/10.3969/j.issn.1000-3428.2012.23.051Because of the problems of Shuffled Frog Leaping Algorithm(SFLA) such as local optimality and slow convergence rate, a leapfrog algorithm with selection and adaptive mutation mechanism is presented. This algorithm introduces the linear decreasing adaptive inertia weight to correct the poor frog update strategy. It selects the frog with better fitness value to substitute the poor, and makes very frog adaptively mutate with different probability. Simulation results show that this algorithm can balance the global search and local search, and its optimization ability is stronger, the number of iterations is less, the solution is better, and the suitable for high-dimensional optimization of complex functions is more.
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Computer Engineering. 2012, 38(23): 211-214. https://doi.org/10.3969/j.issn.1000-3428.2012.23.052Aiming at multifocus image fusion, a new method is proposed based on morphological Haar wavelet decomposition and recomposition. By the new method, morphological Haar wavelet is used to decompose two original images, when image edges and details are hold in low frequency coefficients commendably. The mean of two low frequency coefficients is chosen as the low frequency coefficients of fused image. Gauss filtering is used to all high frequency sub-bands, wiping off noise and fringe effect. The bigger one of two corresponding high frequency coefficients is chosen as the same high frequency coefficients of fused image. Morphological Haar wavelet is used to recompose fused image from the fused coefficients. Experimental results show that this method performs better in preserving edge information and details for the test images than other image fusion methods.
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Computer Engineering. 2012, 38(23): 215-218. https://doi.org/10.3969/j.issn.1000-3428.2012.23.053In order to improve the assessment accuracy of white noise, Gauss blur, JPEG2000 compression and other distorted images, this paper puts forward an image quality assessment method based on Support Vector Machine(SVM) and Particle Swarm Optimization(PSO). It extracts the sample image data and determines the assessment indexes. It pre-treats the sample data, including normalized and Principal Component Analysis(PCA) dimensionality reduction process. It uses PSO to select the optimal parameters. It uses the best parameters to train the training set data. It predicts and analyzes the predictive set data and establishes the image quality assessment model. Experimental results show that the image quality assessment method has a higher accuracy than traditional method and it can accurately reflect the image visual perception of the human eye.
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Computer Engineering. 2012, 38(23): 219-223. https://doi.org/10.3969/j.issn.1000-3428.2012.23.054The edge of the black handle region in the coal-fired flame images is fuzzy or incomplete, directly using the Canny detection operator cannot accurately detect the edge information. Aiming at this problem, this paper proposes the DTCWT fusion detection method based on sparse de-noising for flame image. It uses DTCWT fusion method based on sparse de-noising to fusion two single frame flame image, then using Canny detection operator for detection and processing. Experimental results show that this method can detect completely black handle edge information on basis of fusing low noise and full shape of the black handle region.
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Computer Engineering. 2012, 38(23): 224-226,230. https://doi.org/10.3969/j.issn.1000-3428.2012.23.055The image fusion of traditional two-dimensional empirical mode decomposition is based on the fusion principle of maximum energy to pixels, but it does not analyze the characteristics information of images, which can not reserved maximum. Aiming at this problem, an image fusion method is proposed based on Bidimentional Empirical Mode Decomposition(BEMD) and Non-negative Matrix Factorization(NMF). Original images are decomposed using BEMD separately and the Intrinsic Mode Functions(IMF) component and residual component are obtained. Then the same level IMF of original images is decomposed using NMF separately and the real IMF as this level image fusion is obtained. The fussed image is obtained using reverse reconstruction. Experimental results show that this method is better than BEMD and NMF on the image clarity and contrast.
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Computer Engineering. 2012, 38(23): 227-230. https://doi.org/10.3969/j.issn.1000-3428.2012.23.056To avoid the rotation of the color distortion and jagged edge of the phenomenon and analysis of the neighbours interpolated models and fitting model of surfaces, an algorithm of image rotation based on the migration theory is presented. The method employs the color palette information to avoid distorted information color, and diminishes the phenomena of jagged edge. Experimental results show that the algorithm gets the image’s outline more clear compared with nearest neighbor methed and fitting model of surfaces methed. Its PSNR is higher than that of nearest neighbor method and fitting model of surfaces method.
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Computer Engineering. 2012, 38(23): 231-235. https://doi.org/10.3969/j.issn.1000-3428.2012.23.057Aimming at the choice of threshold under over-compeleted sparese shrinkage denoising of image, a new adaptive threshold selection algorithm is investigated over image normal sparse model based on SURE agonic estimation. Based on the one order derivable shrinkage function, the optimal objective function about threshold selection is derived and it is shown to be convex function on threshold, and then its global minimum is searched by golden section method. Simulation result shows that the choice of threshold is closer to the maxima of PSNR-threshold curve. The new algorithm is extended over image block sparisity model, and a better denoising result than normal sparse model is gotten.
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Computer Engineering. 2012, 38(23): 236-239. https://doi.org/10.3969/j.issn.1000-3428.2012.23.058In general, the synchronous serial communication interfaces often have the problems of low data transfer rate and poor flexibility when transfering data. A fully new serial communication interface is proposed in this paper. A new data transfer protocol is defined, in which multiple data types and the function of address prediction are added. The interface circuit is implemented by the Hardware Description Language(VHDL) and synthesized in TSMC’s 65 nm CMOS process. Simulation and synthesis results coincide with high data transfer rate of 125 MHz, and the design is successfully applied in a 32-bit Digital Signal Processor(DSP).
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Computer Engineering. 2012, 38(23): 240-242,246. https://doi.org/10.3969/j.issn.1000-3428.2012.23.059Aiming at the slow operating speed of existing AES and SHA-3 candidates Gr?stl algorithm, this paper presents a design scheme for algorithm acceleration using Reduced Instruction Set Computer(RISC) coprocessor. Data cache is multiplexed as look-up table by the coprocessor for acceleration. Several specific instructions are added to the RISC instruction set architecture to accelerate the operation. Experimental results show that the scheme can reduce hardware cost compared with the implementation using traditional parallel on-chip look-up.
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Computer Engineering. 2012, 38(23): 243-246. https://doi.org/10.3969/j.issn.1000-3428.2012.23.060This paper designs an intelligent home remote monitoring system based on ZigBee and General Packet Radio Service(GPRS). The system adopts CC2430 and some sensors to construct a ZigBee home LAN, and remote supervision is achieved by GPRS network and Internet client control software. The realization of hardware framework and the upper computer software architecture are presented, including network topology construction process and design of wireless nodes and client software. The test of this system in practice shows that it has strong stability and high efficiency, performs great flexibility.
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Computer Engineering. 2012, 38(23): 247-250,265. https://doi.org/10.3969/j.issn.1000-3428.2012.23.061In order to detect visible foreign substances in oral liquid, which is packed in cylindriod vial, an automatic recognition and sorting system is developed. Using multiple detection station and multiple camera tracking shot mode, it can avoid error judgment effectively. Due to the shape change of plane image caused by the movement of visible foreign substances, the paper presents a kind of detection algorithm aiming at small targets in the liquid. The detection target is obtained via complex difference. A kind of particle filter tracking algorithm based on weighted feature is proposed, overcoming error tracking by single feature, it can distinguish interference and visible foreign substances effectively. Experimental results show that this method can satisfy the speed and accuracy demand of online detection.
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Computer Engineering. 2012, 38(23): 251-254,269. https://doi.org/10.3969/j.issn.1000-3428.2012.23.062In order to realize intelligent fault diagnosis of the EAST cryogenic system, knowledge storage and diagnosis expert system of cryogenic system based on fault tree is proposed. According to the structure of fault tree model, knowledge storage based on level in the relational database is designed. Fault Tree Analysis(FTA) method is applied to build fault model and diagnosis inference, combined with reliability factor to assist uncertain inference, and the inference arithmetic is explained in detail through an instance. Simulation diagnosis results indicate that the expert system has a friendly interface, stable performance and reliable diagnosis results.
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Computer Engineering. 2012, 38(23): 255-258. https://doi.org/10.3969/j.issn.1000-3428.2012.23.063This paper presents a highly-parallel Turbo decoder architecture. It utilizes 32-parallel radix-4 component decoders and its throughput is increased by 43.2% at most with modified sliding window and memory partition scheme. The proposed decoder is implemented in SMIC 0.13 μm technology, which has 1.94 M equivalent gate counts and achieves 1.19 Gb/s running at 294 MHz with 5.5 iterations. It meets the peak data rate requirement of 4G mobile communication standard LTE-Advanced.
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Computer Engineering. 2012, 38(23): 259-262. https://doi.org/10.3969/j.issn.1000-3428.2012.23.064Traditional asset management system is separated from the network operation and management systems, and there is no efficient mechanism in data sharing and data synchronization between them, resulting in the lack of workflow monitoring and life cycle management of asset management system. This paper proposes an implementation of asset management system based on network management platform. It integrates the two systems by sharing the unified asset data and leverages the workflow skills to realize business process management and life cycle management. The operating results show that this scheme is a feasible way to solve the issues about data redundancy and information island as well as improving the ability of informationalization and flow process.
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Computer Engineering. 2012, 38(23): 263-265. https://doi.org/10.3969/j.issn.1000-3428.2012.23.065A new signal constellation mapping scheme of 8PSK modulation is proposed for Bit Interleaved Coded Modulation with Iteratively Decoding(BICM-ID). The scheme which is based on the signal labeling designs criterion of the average near neighbor hamming distance in low SNR, the symbol is divided into two QPSK with different radius and phases. It reduces the average near neighbor hamming distance by way of adjusting radius. Performance analysis and simulation results show that the proposed scheme achieves better performance than the convectional signal mapping for BICM-ID in low SNR.
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Computer Engineering. 2012, 38(23): 266-269. https://doi.org/10.3969/j.issn.1000-3428.2012.23.066For the erase-write feature of NAND Flash, how to enhance the space utilization, reduce erase operation times and RAM cost is a critical issue for the resource-limited embedded systems. This paper presents an improved algorithm for the NAND Flash, redefines the switch operation and merge operation, and makes the switch operation instead of the merge operation of sequence write log block. Compared with the traditional FAST algorithm, the improved algorithm reduces one times erase operation and improves the space utilization by statistical methods.
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Computer Engineering. 2012, 38(23): 270-272. https://doi.org/10.3969/j.issn.1000-3428.2012.23.067The single-session management of traditional streaming server is not able to satisfy the business requirement any more when facing the industry standard of new type of interactive television. To solve the problem, this paper proposes and implements a double-session management mechanism, which can make an effective distinction and management of different types of clients. Experimental results show that this method can save server resources effectively and the practical business platform, and further verifies its feasibility and reliability.
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Computer Engineering. 2012, 38(23): 273-276. https://doi.org/10.3969/j.issn.1000-3428.2012.23.068Aiming at the problem that the strong data dependency and low parallelism in Context-based Adaptive Binary Arithmetic Coding (CABAC), this paper proposes an optimized real time CABAC decoding architecture for H.264/AVC high profile in HD application. The architecture is based on the two-level storage structure and adopts syntax element prediction and merging strategies, optimizes the decoding decision processing and reuses the de-binarization circuits. Test results show that the architecture achieves a high performance with a low cost, and it is sufficient for HD application in FPGA.
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Computer Engineering. 2012, 38(23): 277-280. https://doi.org/10.3969/j.issn.1000-3428.2012.23.069In general, the delivery terminal that an express address belongs to is determined manually when sorting the goods at the express distribution center. In order to improve automation and speed, an automatic classification approach of express address based on the probability statistical model is proposed. The probability statistical model counts the probability distributions of the minimum address element, and determines the delivery terminal that the goods should be sent to. Experimental results based on the real data show that the classification accuracy of the approach reaches 99%, and classification speed is 0.43 ms per address.
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Computer Engineering. 2012, 38(23): 281-283. https://doi.org/10.3969/j.issn.1000-3428.2012.23.070The original sample entropy algorithm can not effectively extract the characteristic difference of Heart Rate Variability(HRV) signals between healthy people and Congestive Heart Failure(CHF) sufferers in short-term nonlinear analysis. This paper presents an improved algorithm of sample entropy based on the Teager Energy Operator(TEO). The heartbeat interval series are preprocessed with TEO to detect the abnormal rhythm in the activity of cardiac dynamics, in order to strengthen the effect of sample entropy analysis. Experimental results of signals from healthy people and CHF sufferers in MIT-BIH database show that this algorithm can significantly reflect the difference of nonlinear complexity between CHF sufferers and healthy people’s short-term HRV signals, and thus can be used as a new auxiliary basis for computer diagnosis of heart failure.
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Computer Engineering. 2012, 38(23): 284-286. https://doi.org/10.3969/j.issn.1000-3428.2012.23.071In watermark detection, Fixed Sample Size(FSS) watermark detection needs large number of signal observations and it is not suitable for applications such as detecting multi-watermarks or video watermark detection. To overcome the difficulty, the sequential watermark detection is researched and an improved method is put forward. In analysis of the sequential watermark detection, the Operating Characteristic Function(OCF) and the Average Sample Number(ASN) are all related with the actual embedding factor. In order to improve the sequential watermark detector performance, a local network is applied to predict the original image because it can reduce the prediction error compared with the simple neighboring pix prediction, and improve the performance of sequential watermark detection.
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Computer Engineering. 2012, 38(23): 287-290. https://doi.org/10.3969/j.issn.1000-3428.2012.23.072According to multiple DAG workflow scheduling problem in heterogeneous distributed environments, a scheduling algorithm is proposed based on minimizing the data transmission time and task completion time, which can deal with the problem that multiple DAG workflows have the same priority, and gives the multi-priority multi-DAG mixed scheduling algorithm. Compared with E-Fairness algorithm, experimental results show that on the basis of fairness to ensure multiple DAG scheduling, this algorithm can avoid additional data transfer overhead, shorten the entire workflow execution Makespan, and improve resource utilization.
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Computer Engineering. 2012, 38(23): 291-292. https://doi.org/10.3969/j.issn.1000-3428.2012.23.073To solve the tag collision problem in Radio Frequency Identification(RFID) system, an improved hybrid query tree anti-collision algorithm is proposed, which adopts the method of hybrid query tree algorithm and multiple ary tree. The algorithm is based on QT algorithm, uses the tags’ collision information generated by tag sequence generator, combines 8-ary query trees, avoids idle circle and compensate slot, reduces tag collisions and system consumption. The results show that, compared with QT and HQT algorithm, the proposed algorithm has lower query times and communication bits between reader and tags, and the improved hybrid query tree algorithm’s identification efficiency is enhanced by 46.1% compared with HQT algorithm.
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