15 October 2013, Volume 39 Issue 10
-
Select all|
-
Computer Engineering. 2013, 39(10): 1-5.The cloud computing service level agreement often only focuses on performance while seldom emphasizes security parameters. Besides, customers are confused by several suppliers in cloud computing market. Therefore, cloud computing Security Service Level Agreement(SecSLA) with detailed indexes is put forward and an improved ELECTRE method is introduced to the cloud provider selection process. Goal-Question-Metric method is employed to form 50 bottom evaluation indexes for SecSLA. The modified ELECTRE method combines the value of net advantage and net disadvantage to simplify the decision process.The calculation and analysis of instance prove the following aspects: the proposed SecSLA has a relatively comprehensive coverage of the cloud computing assessment factors, such as incident handling, vulnerability and patch management,compliance and availability; the suggested method eliminates the redundancy and dependence on experience of ELECTRE II, which makes the realization of automatic process easier. The final evaluation order conforms to the result of ELECTRE II, gray correlation method and TOPSIS method, which indicates that the designed method can play a guiding role in the selection of cloud service provider.
-
Computer Engineering. 2013, 39(10): 6-9.Current remote attestation schemes for cloud computing lack researches on trusted node of Infrastructure as a Service(IaaS). They can not effectively prevent the attestation from untrusted nodes based on IaaS. To overcome these shortcomings, this paper puts forward a threshold remote attestation scheme based on Trusted Cloud Computing Platform(TCCP), which uses verifiable secret sharing algorithm and threshold signature algorithm to implement the remote attestation of trusted nodes in the cloud environment. It also can evaluate the running state of the node and the cluster to implement dynamic metrics for each node in the cluster. The scheme can prevent conspiracy attack and the remote attestation of untrusted nodes based on the assumption of the Collusion Attack Algorithm with K traitors (K-CAA) in the random oracle model. Different critical trusted threshold values are tested in the research. The results show that efficiency of the scheme increases with the threshold value increases and critical trusted threshold decreases.
-
Computer Engineering. 2013, 39(10): 10-13.In high speed networks, the forwarding performance of a network device which captures flows is inevitably degraded. A parallel flow generating approach based on small size cloud computing platform outside of network device is proposed. A small size cloud can be deployed near the selected network device being monitored, and packet traffic through the network device is copied into the cloud. Then flow records can be extracted fast from the large volume packet traffic by the parallel Map-Reduce framework of cloud. A parallel flow extraction algorithm based on Map-Reduce framework is proposed. In addition, cloud scale is flexible to expand, and by configuring proper cloud workers, this approach can be adopted to analyze network traffic in arbitrary size. Real network packet traffic is used to verify the performance of the parallel flow generating approach. Analysis results show that in clouds consisting of 3, 5 or 7 worker nodes, 15 160 052 flows are recognized from more than 40 GB text packet data, and comparing against sequentially processing method, the consumed time are reduced by more than 85%, 90% and 94%, respectively.
-
Computer Engineering. 2013, 39(10): 14-18,23.At the beginning of Software as a Service(SaaS) platform construction, service providers need to invest the initial cost of the software and hardware environment, rente server and deploy the application instances. As only customers’ needs and the types of server are known for the initial deployment, while the amount of server/virtual machines and SaaS applications needed is unknown. To solve optimization deployment problem under that uncertainty, this paper puts forward a multi-tenant SaaS optimization deployment model, including multi-tenant resource consumption model and optimization deployment problem model, uses a Genetic Algorithm(GA) based on greedy strategy to solve the model, and gives optimized deployment stratege. Experimental result shows that this algorithm has better adaptability and scalability. The given strategy can provide a theoretical basis for the actual deployment of platform constructiong.
-
Computer Engineering. 2013, 39(10): 19-23.
In order to solve the problem of load imbalance of Distributed Hash Table(DHT) cloud storage system, this paper proposes a load balancing algorithm based on Node Dynamic Forward(NDF). Through overload nodes forward, this algorithm can reduce the node’s partition, and thereby reduce the storage node load. At the same time, copy the corresponding data to the third successor node, to ensure the stable number of copies the data in the system. In the NDF implementation process, it only needs a simple coordination between overload node and the third successor node. Therefore, multiple overloaded nodes can concurrently do load transfer, which is suitable for deployment in a large cluster. The functional test in a minor cluster of 10 nodes verifies that the NDF has good ability of load balancing. The performance test in a massive cluster of 5 000 nodes demonstrates the total system load does not exceed 60%, and compared with the virtual node algorithm, NDF algorithm can improve the load transfer cost by more than 30%.
-
Computer Engineering. 2013, 39(10): 24-30,36.Aiming at the systematic research of the network traffic generated by cloud storage services, an automatic test tool is designed based on the analysis of cloud storage services. And an estimation model of network flow is put forward. The user experience under various network Quality of Service(QoS) conditions is also measured. Experimental data show that cloud storage service can generate a data deluge of several Gb/s. There is a gap between the overall transaction times of two different kinds of servers. Packet loss rate lower than 2% has a smaller effect on cloud storage services. Bandwidth between 4 Mb/s and 6 Mb/s is more cost efficient. Either reducing network delay time and packet loss rate or increasing access bandwidth can improve the Quality of Experiece(QoE). A cloud storage service framework based on the perception of capabilities of network devices can ensure better network QoS condition which has advantages of smaller investment, easier deployment and full use of existing network resource compared with traditional method of network expansion.
-
Computer Engineering. 2013, 39(10): 31-36.This paper emphasizes on building a new evaluation method of Software as a Service’s Service Provider(SaaSSP) service quality based on Service Level Agreement(SLA). Based on the evaluation indicators of Software as a Service(SaaS) electronic service quality in the empirical research, this method is developed with consideration of user’s expectation which is result from SLA and adoption of the thought about quality gaps in the classical SERVQUAL model. Example results show that this method can combine the service quality gaps model and the characteristics of SaaS model well and it can provide reference to evaluate SaaSSP service quality.
-
Computer Engineering. 2013, 39(10): 37-41,52.In order to achieve centralized management, efficient use and privacy control of computer resources, a cloud-desktop system based on video stream is designed and implemented. A general-purpose server with VirtualBox virtualization technology is applied to achieve desktop virtualization. A freescale i.MX6DL ARM processor for hardware decoding is the core of client terminal. The improved state-of-the-art H.264 video compression standard is applied in desktop image compression. A smooth network traffic transfer method is used in desktop video stream transmission. The Linux kernel module is used to redirect mouse and keyboard messages. Experimental results show that when the virtual desktop resolution is 1 280×720, this cloud-desktop has a more stable display quality and less network traffic around 500 KB/s compared with commonly used desktop transfer protocols, in addition the very short response time around 120 ms.
-
Computer Engineering. 2013, 39(10): 42-48,56.The computing resource of the sensor node in the Internet of Things is very limited and there are security risks in the cloud. To implement a verifiable cloud access control service for the node in the sensor network, this paper proposes an Extensible Access Control Markup Language(XACML) based verifiable cloud access control scheme according to the Refereed Games(RG) model. Specifically, it firstly designs a verifiable cloud access control model based on the XACML access control model. Furthermore, it designs verifiable cloud access control decision and verification schemes for policy and policy-set based on decision and policy combination algorithm in XACML, in which a high efficient access control with complex access control policy is realizable by the node in sensor network. Compared with the traditional access control scheme, the experiment on Amazon EC2 shows that the verifiable Cloud access control was implemented with much higher efficiency in this scheme.
-
Computer Engineering. 2013, 39(10): 49-52.
null
-
Computer Engineering. 2013, 39(10): 53-56.To deal with the inefficiency generation test data existing in Basic Particle Swarm Optimizer(BPSO) for multi-path to the target branch node, automatic generation method of test data for software structure is proposed based on Multiple-population PSO(MPPSO) algorithm, which includes modified individual migration strategy and the restrictive function of predicate redefined, and uses the search method of parallelism. Experimental results show that the iterative number and execution time of MPPSO algorithm is respectively 1/7 and 1/3 in contrast to BPSO, and it has obvious advantages in the efficiency of the execution and search.
-
Computer Engineering. 2013, 39(10): 57-62,67.The characteristics of cyber physical systems such as cyberization, systematization and informationization make the software systems more and more complex. Because the classic modeling methods cannot satisfy the needs of Cyber-physical System(CPS), the Spatio-Temporal Consistence(STeC) language for real-time systems whose core property is the consistence of time and location is introduced to model the real-time systems. In order to achieve the automatic logical reasoning in STeC, the equation and rewriting rule in Maude are applied to convert the STeC system to an executable specification description, it can analyze the result of computation and check the correctness of time in the system. Instance results show that the formal description language Maude can effective for real-time system for security verification.
-
Computer Engineering. 2013, 39(10): 63-67.Out-Tree task graph is one of basic structurs in task scheduling, and the problem of wasting processors is revealed when many previous algorithms work on it, which results in poor schedule efficiency. This paper proposes a new heuristic algorithm with task duplication based on mean value, which tries to get the shortest schedule length and takes load balances into account to economize the used processors. Experimental results show that the proposed scheduling algorithm can produce better schedule which has less number of used processors and higher efficiency.
-
Computer Engineering. 2013, 39(10): 68-71,75.Aiming at the problem of low precision in the state of program log parsing technology, a new log parsing technology is proposed. This approach conducts interprocedural method analysis on the abstract syntax tree of the program, while applying Java string analyzer for intraprocedural data flow analysis. The work combines the results and builds an automaton for each log point to do the mapping against the console log. Experimental result shows that compared with existing technology, the new approach significantly improves the precision of log parsing.
-
Computer Engineering. 2013, 39(10): 72-75.As to using radio wave propagation prediction in urban areas, the process of intersection detection for the tracing of Gaussian beams is too complicated, this paper proposes a space division method based on quad-tree to equally distribute the obstacles of the scene into a series of sub-space and accurately locate the grids where the axis of the beams cross through. Simulation result shows that the accelerated Gaussian beam tracing method is roughly equal than and as accurate as ray racing, but prediction efficiency can be increased several times, which is quite useful for the design and optimization of wireless network.
-
Computer Engineering. 2013, 39(10): 76-80.On the basis of path loss model in urban road typical application environment, this paper proposes a quadratic path loss model and verifies the effectiveness and practicality of the new model by comparison with the existing classical model in fitting error distribution, root-mean-square error and squared relative coefficient. Result shows that for a typical application environment which is short in distance, near the ground and rich in scattering, relationship between the path loss and the logarithmic distance is more likely to a quadratic attenuation relationship compared with the classical quadratic path loss mode, rather than a linear attenuation relationship in the traditional sense.
-
Computer Engineering. 2013, 39(10): 81-85.The communication qualities of the wireless links between the neighbor nodes are poor and unstable which may be caused by node energy exhaustion, node physical destroy or environment inference. The invalidation of wireless links can cause the route breakdown, packet loss and retransmission, which weaken the reliability of the data transmission. Numerous studies show the difficulty to improve the energy efficiency and reliability of routing protocols due to the local unbalanced traffic load distribution. This paper proposes a reliable routing protocol based on load-balancing, namely RR. This protocol employs some mechanisms, including continuous gradient parameter and dynamic link quality evaluation. Experimental results show that this protocol achieves better performance in energy consumption, load balancing and delivery rate.
-
Computer Engineering. 2013, 39(10): 86-89.Array antenna is one kind of receiving antenna for earth state in the satellite communication system. However, the Doppler frequency shift exist if the carrier synchronization is not used in the digital down conversion. The spatial adaptive filter is analysed based on the array signal model in the case that Frost Least Mean Square(LMS) algorithm is employed. Simulation result of direction diagram of receiving array antenna and signal spectrum shows that Doppler frequency shift can not impact the performance of spatial filter, and the correctness of the method.
-
Computer Engineering. 2013, 39(10): 90-93.Aiming at the problem that Controller Area Network(CAN) in micro-satellites onboard applications works properly only in the situation when each node holds a legal node-address which is pre-configured manually, a self-organization method for micro-satellites’ CAN is introduced, which divides the network operation status into normal and configuration mode, it helps to discover automatically the nodes joining in CAN network by matching physical address step by step, and then configures them with assigned node-address using network address table. Experimental results show that self-organizational satellites onboard CAN network can discover and configure effectively the nodes connected to the network, and the average configuration time is less than 30 milliseconds, contributing to rapider assembly, integration and test of satellites electronic systems, and greatly reduce the development time.
-
Computer Engineering. 2013, 39(10): 94-98.Aiming at the problem of the pinball routing and multi-layer packet encapsulations in nested Network Mobility(NEMO), this paper proposes an optimization scheme for the nested NEMO. It slightly extends the modification of the mobile IPv6 and IPv6 neighbor discovery protocol, uses the return route procedure to establish the binding of Mobile Network Node(MNN) and Correspondent Node (CN) directly. Theory analysis and simulation results show that the packets does not require one by one after each MR’s HA, this scheme shortens the transmission path of the data packets, reduces the transmission delay greatly, solves the pinball routing problem in nested NEMO effectively, and improves the efficiency of data packets transmission.
-
Computer Engineering. 2013, 39(10): 99-104.Due to great carrier frequency deviation under high speed vehicular wireless environment in 4G network, the existing estimation algorithms perform ineffectively in terms of complexity and the estimated error. This paper proposes a dynamic cooperative frequency offset estimation algorithm. This estimation algorithm uses a weighted frequency offset estimation model for each receiver. The model not only allows for the weight of Signal to Interference plus Noise Ratio(SINR)but includes the weight of strong path signal. Monte-Carlo method is used to simulate the vehicular Orthogonal Frequency Division Multiplexing(OFDM) system. Numerical results of cooperation model are compared with conventional algorithms. Results show that the cooperative estimation algorithm can improve performance of error rate for Long Term Evolution(LTE) system.
-
Computer Engineering. 2013, 39(10): 105-109,115.In order to improve the resource utilization of the power line communication system, this paper proposes a modified Invasive Weed Optimization(IWO) algorithm to allocate resources. Under the criterion of Rate Adaptation(RA), the binary discrete IWO which has directed variation in the individual random position is proposed to realize the optimal subcarrier allocation, which not only meets the constraint of emission power spectrum, but also takes the fairness among users into account. In the environment of a typical power line communication system, simulation results show that, the modified IWO makes the power line communication system have greater throughput and better fairness, and improves the system performance effectively.
-
Computer Engineering. 2013, 39(10): 110-115.In order to solve the problem of constituting large scale mobile Ad Hoc network in some special environment. A new model of mobile multi-protocol fusion gateway is proposed. The gateway transmits data among Ethernet, Wireless Local Area Network(WLAN) and multi-layer Ad Hoc network by integrating several routing protocols in IP layer. Based on the different function in Ad Hoc, a new hybrid routing protocol is proposed to decrease the routing finding converging time and increase the efficiency of network self-adaption. The gateway is modeled by OPNET and the network topology which includes gateway is simulated. Results show that the gateway meets the requirement of constituting heterogeneous network in mobile environment quickly, stably and flexibly and it performs well in exchanging and transmitting data packages in heterogeneous network and ensures the demand of Quality of Service(QoS) which running over heterogeneous network in mobile environment and reduces the converging time of routing protocol simultaneously.
-
Computer Engineering. 2013, 39(10): 116-119,122.It is not easy to construct a secure Deterministic Public Key Encryption(DPKE) schemes under Auxiliary Input(AI) environment. Aiming at this problem, based on a new intractable problem named d-decisional Diffie-Hellman(d-DDH) problem introduced recently, a new DPKE scheme under AI environment is proposed in this paper. The scheme is proved to have privacy strong indistinguish- able security in the standard model under the d-DDH assumption. Some methods and theories such as matrix encryption, matrix d-DDH, and Goldreich-Levin theorem for finite fields are used in the construction and security proof of the scheme. The d-DDH problem on which the scheme is based is more intractable than decisional Diffie-Hellman Problem(DDHP). Moreover, it can select different d for different security demand of applications.
-
Computer Engineering. 2013, 39(10): 120-122.Aiming at the key management in public key cryptosystem and personal privacy protection for signers, a certificateless strong designated verifier signature scheme on conic curve over ring Zn is put forward by using the public key cryptosystem and signature scheme on conic curve over ring Zn. It is based on the RSA signature technology on the conic, which can resist the little private key attack compared with scheme on finite field. Analysis results show that there are properties of un-forgeable and strong designated in this scheme under the discrete logarithm problem on conic curve and large number factorization problem. Compared with the identity-based scheme, it can reduce two times pair operation and one time Hash operation, and has higher efficiency.
-
Computer Engineering. 2013, 39(10): 123-126,132.In response to the defects that the length of proxy signature key and signature will increase when the dimension of lattice which proxy uses increase is larger in the proxy signature schemes which are on the principle of bonsai tree over the lattices, a new proxy signature scheme is put forward, in which the length of signature is controllable. According to the linear relationship between the length of proxy signature and the dimension of lattice, using the lattice basis delegation algorithm with fixed dimension to generate proxy signature keys, the proxy signature scheme is constructed on the pre-image sample function. Based on the hardness of the Small Integer Solution(SIS) problem and the Shortest Vector Problem(SVP), it proves the scheme security. The proof results show that the new scheme has non-forgeability in the condition of keeping the length of proxy signature key invariance.
-
Computer Engineering. 2013, 39(10): 127-132.As the generation of attack graph without loops leads to missing of attack paths, this paper puts forward the concept of complete attack graph and builds its automatic generation method. It obtains the network connectivity automatically by analyzing the firewall configuration files, to get rid of tedious manual input. Then the attack patterns are enriched to cover almost all network attack types and based on them, an efficient approach to complete attack graph generation is built. In the end, a model to generate complete attack graph automatically using the algorithm is built. Experimental result shows that this method has less time consumption, high degree of automation, and it can be applied to large networks.
-
Computer Engineering. 2013, 39(10): 133-137,142.With the continuous improvement of the integration level of the power system, the information security risks it facing increased contrast, how to comprehensive evaluate information security of integrated platform becomes the key issue to improve the level of business applications. Aiming at complex system architecture for the integration of information integrated platform, this paper studies information safety assessment index system modeling using Fuzzy Analytic Hierarchy Process(FAHP) and improved D-S evidence theory, puts forward a set of information security integrated platform rating system. It takes a regional of Guangdong province metering automation system for instance, to verify the feasibility and effectiveness of the information security level assessment system.
-
Computer Engineering. 2013, 39(10): 138-142.Aiming at the problem that traditional security management system can not reflect the security status of the entire system, a method based on rough set and D-S evidence theory is presented. It uses attribute reduction and attribute values reduction in rough set theory to optimize the evaluation indicators and get the simplest rules, determines the value of the evidence in the rough set and D-S theory combination rules according to the importance of the attribute in the decision table, gets Basic Probability Assignment(BPA) based on the decision table and establishes a system security assessment model. Experimental result shows that this method can optimize evaluation indicators, get the simplest rules, and improve the reliability of security assessment.
-
Computer Engineering. 2013, 39(10): 143-146.The traditional double two out of two redundancy structure switches by hot standby mode between two subsystems, the availability of the system is not high and the data loss will possibly happen. Aiming at this problem, a new redundancy structure for safety computer, quadruple modular parallel voting structure, is proposed in this paper. The working mode of parallel voting reduces the effect of the undetected failure in a single subsystem. The safety of the structure is analyzed with Markov model. Tripe module redundancy structure, double two out of two redundancy structure and dual hot-standby structure are compared by the data of Matlab simulation. The result shows that the reliability of quadruple modular parallel voting structure is better than the other three structures, and the safety is higher than tripe module redundancy and dual hot-standby structure. Moreover, the characteristic of maintenance can improve the system reliability.
-
Computer Engineering. 2013, 39(10): 147-150.In order to increase the steganography rate, this paper proposes a new scheme of steganography which is based on YASS algorithm. After discussing the inherent relationship between Discrete Cosine Transform(DCT) coefficients in different blocks, a method of iterative programming is proposed which is referenced to integer programming, and the carrier which has steganography has been corrected. In aspect of anti-detection, 98 degree’s Markov steganalysis method is used to detect the stego images. Experimental result shows that this optimization algorithm is proved to effectively decrease the errors caused by JPEG compression during YASS steganography. In this way, steganographic rate is increased to a great extent. This method is also proved to get the same outstanding performance in common anti-detection.
-
Computer Engineering. 2013, 39(10): 151-155,161.Security assessment of command automation network which can comprehensively master the running status of the network and take immediate precautions plays an extremely important role on developing the combat effectiveness of the command automation system. Fuzzy Analytical Hierarchy Process(FAHP) and neural network are used to build the network security evaluation system according to the relevant influencing factors. Through analysis of simulation results, it proves that the results are satisfied and the LMBP algorithm achieves a better effect on the rate of convergence and the accuracy.
-
Computer Engineering. 2013, 39(10): 156-161.Aiming at data association problems about robot Simultaneous Localization and Mapping(SLAM), this paper presents an optimized multiple hypothesis data association approach to SLAM problem based on FastSLAM. This method uses dynamic threshold to reduce the number of probable data association solution. After that, FastSLAM is combined with multiple hypothesis data association method, and a new particle weight is composed with the product of FastSLAM particle weight and multiple hypothesis data association posterior distribution probability. FastSLAM resample is used to reduce relevance trees compounding. Experimental result indicates that it can modify error data association solution in certain degree compared with JCBB, complete data association well, and improve the accuracy for localization and mapping.
-
Computer Engineering. 2013, 39(10): 162-166,171.To solve the problem of slow convergence speed and low optimization precision of Shuffled Frog Leaping Algorithm(SFLA) in later stage of evolution, the optimization SFLAs are proposed in this paper. By introducing the sharing factor, it is divided into global sharing factor and local sharing factor. The idea of three algorithms by adopting two types of sharing factor to SFLA is introduced, and the optimization performance of Shuffled Frog Leaping Algorithm Based on Global Sharing Factor(GSF2LA) is analyzed. Algorithm steps are given and its efficiency is analysed. Experimental results indicate that GSF2LA can effectively improve convergence speed and precision in optimization problem of single peak function and multi-peak function in respectively fixing the condition of global evolution times and convergence precision, and it improves the optimization performance of SFLA.
-
Computer Engineering. 2013, 39(10): 167-171.Traditional sentiment analysis methods aim at same domain documents, the performance becomes worse for different domain documents. To solve this problem, this paper presents an opinion analysis method of cross-domain product reviews based on feature transformation. This proposed method builds the relevance of domain dependent words between source domain and target domain via domain independent words so that it can transfer acknowledge from the source domain to the target domain. It solves the classifier performance decreasing problem due to different data distributions. The product reviews are used as a corpus in the experiment. The average accuracies are 76.61% and 76.81% by using the methods of Support Vector Machine(SVM) and logistic regression respectively in all corpora. The results are higher than Baseline algorithm.
-
Computer Engineering. 2013, 39(10): 172-175,180.
Aiming at incomprehensive description of 3D model of Silhouette descriptor(SIL) and Density-Based Framework(DBF), this paper proposes a new 3D model retrieval algorithm: Density-based Contour(DBC). It characterizes a 3D object using multivariate probability functions of the object’s 2D contours’ features. Two models can be compared by the similarity of their 2D contours’ probability functions. The new algorithm performs better than SIL on describing contours of the model and it also shows stronger resistance to noise than DBF. The retrieval performance on PSB shows that DBC has a higher retrieval accuracy comparing to other traditional state-of-the-art 3D model retrieval algorithms.
-
Computer Engineering. 2013, 39(10): 176-180.Virtual shadow is kind of false foreground which is produced by the partial change of the background. As common foreground detection algorithm is hard to identify the virtual shadow in complex environment, a virtual shadow elimination algorithm based on improved codebook model in YUV color space is proposed. Algorithm starts from the production principle of the virtual shadow, and separately models the foreground and background. And a conversion is designed for converting the foreground to background under the control of the preset parameter. Experimental results show that on three categories of ghost the algorithm can quickly and accurately remove the ghost and run in real time. The proposed algorithm is helpful for the foreground object identification.
-
Computer Engineering. 2013, 39(10): 181-186,191.Fuzzy ontologies can be built to effectively deal with uncertainty and ambiguity for domain knowledge modeling. Merging multiple fuzzy local ontologies may implement semantic integration of multiple data sources and semantic interoperability between heterogeneous systems in distributed environment. In order to solve the problem of semantic inconsistency mappings for fuzzy ontology merging, this paper presents an automatic detection algorithm of semantic inconsistency mapping which includes sub detection methods of semantic circular inconsistency, subclass-of axiom redundancy inconsistency, attribute inconsistency and disjoint axioms redundancy, and adopts corresponding processing strategy according to different type of inconsistency mapping respectively, and establishes fuzzy ontology merging system based on automatic detection and processing. Experimental results demonstrate that the automatic detecting algorithm saves time and cost of traversing local ontologies, and the accuracy of this system is higher than traditional merging systems, such as GLUE, PROMPT, Chimaera.
-
Computer Engineering. 2013, 39(10): 187-191.Geographic Information System(GIS) is described by semantics. There is no color or gray information in GIS. The matching between aerial images and GIS has to rely on structural features. Restricted by current image processing techniques, the features extracted from images are low informative, have low precision, and usually contain noises. Aiming at these problems, a graph-based matching framework is proposed to align the GIS model and the aerial image. The Undirected Weighted Graphs(UWG) are constructed automatically using the angle between segment lines called UWG-SA for GIS and the extracted image features, respectively. A Graduated Assignment(GA) method is performed to find the global correspondences. It uses the main-direction method to eliminate the incorrect match sets and get the transformation parameters. Experimental results show that the matching probability is about 98.5%, the average matching error is about 8.54 m, and the average cost time is 0.075 s. The algorithm can basically meet the demand for aircraft navigation.
-
Computer Engineering. 2013, 39(10): 192-195,199.Affected by changing illumination, expressions and posture of the face image to the performance of Face Recognition(FR), this paper presents a FR method based on data fusion. The proposed method transforms face image with 2Dimensional-Discrete Wavelet Transform(2D-DWT) into three layers and each image consists of one low frequency sub-image and nine high frequency sub-images. It considers that the low frequency sub-image can directly represent the essence of the face while part of the high frequency sub-images still contain discriminative information, and selects sub-images including abundant of human face information under Fisher projection. It designs three data fusion methods correspond to the pixel level, feature level and decision level. Experimental results on ORL and YALE A face databases show that the proposed method is efficient and its accuracy rate is better than Principal Component Analysis(PCA) method and wavelet transform face recognition method.
-
Computer Engineering. 2013, 39(10): 196-199.This essay puts forward an improved ant colony algorithm based on the introduction of the variability of non-uniform mutation operator. It makes the path optimization, which uses optimized ant colony algorithm to complete the task of ant colony after the completion of one iteration and non-uniform mutation operator mutation. It can speed up the convergence of the algorithm. The satisfactory results are reached after N evolutions. Simulation results demonstrate that the optimal solution and stability of the improved algorithm are better than the basic ant algorithm and Ant Colony Optimization(ACO) algorithm.
-
Computer Engineering. 2013, 39(10): 200-202,207.For the system of multi-sensor data fusion, it is difficult to know the properties of kinematic noise and measurement noise in the time registration. To solve these problems, time registration algorithm based on adaptive Kalman filtering is proposed. This algorithm uses the adaptation to estimate the properties of kinematic noise and measurement noise, and thus preprocesses the sampling data before time registration. Experimental results show that this algorithm has better numerical stability, larger dynamic range, and stronger adaptability. It improves the accuracy of the time registration.
-
Computer Engineering. 2013, 39(10): 203-207.In the standard Particle Swarm Optimization(PSO), the premature convergence and slow searching of particles decrease the optimization ability of the algorithm. By analyzing global and local search ability, a new adaptive PSO algorithm of dynamic control parameters is proposed. It changes the parameter’s value of learning factor and Inertia weight by particle’s fitness to enhance particle’s search ability. Compared with the standard PSO, experimental result of some typical testing functions proves that the new algorithm has a higher convergence efficiency and faster search speed.
-
Computer Engineering. 2013, 39(10): 208-211.Based on neural network theory and phase-space reconstruction theory, a prediction algorithm for chaotic time series of optimized Radial Basis Function(RBF) neural based on Differential Evolution(DE) is proposed. In order to get the optimal neural network predictive model, the center, width, and connection weights of RBF neural networks are optimized by the global search ability of DE. The availability of the prediction algorithm is proved by the simulation of three typical nonlinear systems. Compared with the forecasting results of RBF neural network, results show that the improved algorithm has better generalization ability and higher forecasting accuracy.
-
Computer Engineering. 2013, 39(10): 212-216.The traditional single camera collection technology cannot guarantee the quality of the face image, and then directly reduces the value of face information in the practical application. Therefore, this paper proposes a best face image acquisition algorithm. In order to enhance the accuracy of pose estimation, the pose estimation algorithm is improved through evaluation angle that has corresponding relationship with face rotation. Multiple cameras are set to collect the same area synchronously. In order to select optimal view, the color skin share of image is compared with each camera gathered at the same time. All of the best perspective face images need to get through the pose estimation, and then pick out a set of frontal face images. As to enhance the coherence of subjective and objective evaluation algorithms, the accuracy of evaluation result is increased for face recognition. The method of improved image quality evaluation algorithm is put forward. Experimental result shows that the algorithm can increase face similarity as an indicator of image quality and adopt a from coarse to fine evaluation framework.
-
Computer Engineering. 2013, 39(10): 217-220.This paper presents the First Order-Partially Observable Markov Decision Processes(FO-POMDP), which is a logical expression of POMDP using situation calculus. And the level of abstraction is an important problem for solving the FO-POMDP. The concept of the granularity of states and the granularity of belief states are proposed. The level of abstraction can be characterized by the granularity. The method of granularity resolution can convert the granularity of belief states. And the distance of different belief states is also presented. The Point-based Value Iteration(PBVI) is extended to the logic level. Experimental results show that the solving speed of this algorithm is faster, and is of better quality.
-
Computer Engineering. 2013, 39(10): 221-226.This paper presents an extraction method based on pattern matching and semi-supervised learning on product comment targets. This method gets seed rules set through making statistics on a large number samples to extract the effective evaluation sentences, and extracts accurate opinion targets through the combination of syntactic structures and the Part of Speech(POS)-distance Correlation Algorithm(PCA). Seed rules and opinion targets are stored in the corresponding pattern libraries, the training and expansion of the learning of rules and opinion targets is carried out by the semi-supervised learning methods and rules of dynamic replacement. Experimental results exhibit measurable improvement, and prove the feasibility of this method.
-
Computer Engineering. 2013, 39(10): 227-231.Without combining the advantages of the ways of Agent and Quality of Service(QoS), the current approaches of semantic Web service composition does not provide users with the best semantic Web services which adjusts users’ QoS preference. Considering the fuzziness of user’s QoS preference and the optimization of services space, this paper formalizes the semantic Web services as actions of Agent, and builds Agent model based on dynamic description logic, thus the goals of semantic Web service can be achieved by making use of the Agents cooperation, while getting the sequences of combination by using dynamic description logic’s reasoning mechanism, and as a result, the best semantic Web services composition is obtained. Some algorithms are provided and the validity and feasibility of this method are proved by an example.
-
Computer Engineering. 2013, 39(10): 232-235.
For the problem that the tracker is hard to be resumed when particle filtering fails to track the target, this paper introduces a method that combines particle filtering with online learning. It uses the validated result of particle filtering as positive sample to update the training set. It uses random ferns as classifier to detect object. When there is a big difference between two results, the particle filter will be reinitialized. Two bit binary pattern is used as the online learning feature. It is easy to be computed, and has invariance to illumination and scale. Experimental result proves that this method has better tracking result than particle filtering and it can track the sheltered and disappeared target.
-
Computer Engineering. 2013, 39(10): 236-240,244.A new Information Content(IC) model is given in this paper which can be used to calculate the IC value of concept in WordNet. The concept of entropy is introduced in the model which considers not only the number of child node of concept and the depth in the tree of taxonomy of WordNet, but also the spatial structure of hyponyms of the concept, the model makes the value of IC of the concept more accurate. Experimental results show that the precision of the semantic similarity algorithms using the IC values computed by the entropy model can be improved.
-
Computer Engineering. 2013, 39(10): 241-244.Traditional Markov Random Fields(MRF) methods used in image segmentation are based on fixed neighborhood, and cannot fully describe detailed information such as edge structure. A new linear variable neighborhood structure of MRF model is presented, and a partial weighted priori energy model is designed to model context information. Neighborhood selection and image label are combined in algorithm, using iteration to get image segmentation results. Experimental results prove that the algorithm can better keep the target edge shape, with good results in detail.
-
Computer Engineering. 2013, 39(10): 245-250,253.The multi-source image fusion is one of the hotspots in image processing in recent decades. There are many different image fusion algorithms and fusion rules, but all these fusion algorithms have their advantages and disadvantages. So, it indeed needs an image fusion framework which can automatically determine the suitable algorithm and fusion rules according to the purpose of application. Based on the status quo, a fusion framework is presented. This framework can adapt to various algorithms and various fusion strategies, and can automatically determine the fusion algorithm, the fusion parameters and fusion rules according to the practical purposes of application. The strategies and rules to eliminate the ambiguity of fusion results are put forward. The rigorous mathematical form definition of these rules is given also. A simple instance system is developed to demonstrate the feasibility of the study conclusion.
-
Computer Engineering. 2013, 39(10): 251-253.Segmenting the iris accurately is a main problem for iris recognition, due to the impact of the eyelids, eyelashes and deformation. This paper presents an iris segmentation method based on variational level set model. It uses gray projection algorithm to locate the pupil, applies a least square fitting algorithm to estimate the boundary between the pupil and the iris, and employs a variational level set model to accurately segment the iris. Experimental results demonstrate the segmentation accuracy of 98.59% for outer edge of the iris is better than using Daugman method, Hough transformation method and improved Hough transformation method.
-
Computer Engineering. 2013, 39(10): 254-257,263.High resolution remote sensing images with abundant details generally have characteristics of great within class differences and unobvious between class differences. Simulating the visual interpretation, this paper proposes a multi-stage binary tree-structured classification algorithm based on sharing features. The multi-class classification problem is divided into multiple binary classification problems, sharing features are extracted to interpret objects of only one class at each binary classification stage, and each interpreted class will not participate in later classification. The proposed method makes use of the phase-out mechanism to complete the whole interpretation of a remote sensing image. Experimental results show that this algorithm has higher classification accuracy compared with other multi-class classification algorithms like K Nearest Neighbor(KNN), Support Vector Machine(SVM) and so on.
-
Computer Engineering. 2013, 39(10): 258-263.In order to select the optimal threshold for automatic image segmentation, a novel method for image threshold based on data field and cloud model, is proposed. The method calculates the global threshold related with local image. According to the threshold, it adaptively divides the image into several sub-areas, and forms a quad tree. It produces the cloud models for each sub-area using backward cloud generator, generates a data field based on cloud model, and implements centroid iteration using adaptive characteristic of data field. It achieves image segmentation with uncertainty, and yields the binary result. The proposed method recognizes the issue on the automatic optimization of image threshold from the point of view of the cognitive physics, and it has uncertainty and global optimization. It is indicated by the quantitative and qualitative experiments that the proposed method yields accurate and robust result.
-
Computer Engineering. 2013, 39(10): 264-266.Based on the sparse representation of image in Shearlet transform, a sparsity regularized convex variational model is presented to recover the degraded images. The regularization term of objective function constrains the ideal image to have a sparse representation in Shearlet domain. Using the surrogate function of objective function, an iterative shrinkage method is deduced to solve convex variational of image restoration. The bivariate shrinkage function is used to decrease the iterations and improve the convergence rate. Simulation experimental results demonstrate that, compared with iterative threshold shrinkage algorithm and two-step iterative shrinkage algorithm, the algorithm is improved greatly in the subjective visual quality and Peak Signal to Noise Ratio (PSNR), and has faster convergence speed.
-
Computer Engineering. 2013, 39(10): 267-270.Based on the research of extracting image texture features using Local Walsh Transform(LWT), this paper proposes an image region copy-move forgery detection algorithm fused with LWT texture features. After dividing the detected image into multiple overlapping blocks with the same size, the algorithm uses LWT to extract an image texture feature vector for each block and estimate the texture complexity of the detected image, which is used to choose the threshold for the determining similar image blocks. It sorts all texture feature vectors in alphabetical order, and calculates the proper threshold value. The algorithm detects and locates the tampered region by predetermined similarity criteria. Experimental results show that the algorithm performs better than the previous detection algorithm based on Principal Component Analysis(PCA) in terms of detection accuracy and false positive rate.
-
Computer Engineering. 2013, 39(10): 271-274,278.In view of the time uncertainty of Operation and Maintenance(O&M) strategies for offshore wind farm and the lack of match description of net planning method, a new method for operation and maintenance strategies based on fuzzy Petri net is proposed. The uncertainty is represented as fuzzy-timing function and the computation of critical path is transformed into a problem of finding the solution by solving state equation based on Fuzzy-Timing Petri Net(FTPN). The possibility of O&M project completion is also discussed in the time restriction. The results show that FTPN can not only express the O&M project properly, but also give a formal representation and effective analysis.
-
Computer Engineering. 2013, 39(10): 275-278.In view of the limitation caused by considering time correlation only in Mean Absolute Difference(MAD) prediction and MAD factor only in bit allocation of basic unit in Rate Control(RC) algorithm for H.264, this paper proposes an improved algorithm in which the predicted MAD is calculated by a combination of linear prediction model and the space-time weighted prediction model, and corrected according to the prediction error of the previous basic unit. Besides, the basic unit complexity is estimated by a combined Peak Signal Noise Ratio(PSNR)-based and MAD-based method, based on which bit allocation is done. Simulation results show that compared with JM8.6, the proposed algorithm not only can make the output bit rate more accurate, but also can improve the average PSNR by 0.1 dB.
-
Computer Engineering. 2013, 39(10): 279-282,286.Network-on-Chip(NoC) system often integrates many heterogeneous components which have different sizes. This NoC has an irregular topology. In the irregular mesh, traditional routing algorithm may not be usable any more. To solve the routing problem, this paper proposes a novel routing algorithm, called INC routing algorithm. INC routing is based on two small routing tables, FDT and IFDT. The simulation result shows that the routing scheme can find the shortest path between two nodes in most cases, which reduces the latency a lot. And the routing tables FDT and IFDT have a fixed size of 12 items. Their sizes do not increase when mesh grows.
-
Computer Engineering. 2013, 39(10): 283-286.The frequencies of music scales are exponentially distributed. This paper proposes an algorithm for note onset detection, which is based on Constant Q Transform(CQT) and adapts to the characteristics of music scales. The music signals are decomposed to a partial matrix through CQT, according to the frequencies distribution of twelve-tone equal temperament. Detection function is generated using the partial matrix. Peaks are picked, and note onset vector is obtained. Experimental results show that the results are superior to those of 2011 MIREX.
-
Computer Engineering. 2013, 39(10): 287-289,293.For the problems that the Progressive Edge Growth(PEG) algorithm can achieve large local girth, but ignores the number of shortest cycles, this paper proposes an improved PEG algorithm, which is called PC-PEG algorithm, using Polynomial of Cycle(PC). After a basic matrix is constructed by PCPEG algorithm, circulant permutation matrices will replace the short cycle in the basic matrix. The new method can eliminate effectively the short cycles in the basic matrix without changing the degree distribution fraction of the basic matrix. Experimental results show that the proposed method not only reduces the number of small cycle significantly, but also reduces the coding complexity for its quasi-cyclic structure.
-
Computer Engineering. 2013, 39(10): 290-293.A novel hybrid mesh generation algorithm for two-dimensional viscous flow computation is proposed. This algorithm includes two interrelated procedures for boundary layer mesh generation and unstructured mesh generation. The reducing march directions at concave corners and adding march directions at convex corners improve the quality and orthogonality of the mesh. The degrading quality of unstructured elements due to the movement of boundary layer fronts can be improved to an acceptable level by using a mesh coarsen scheme. Mesh examples are presented to demonstrate that the algorithm can guarantee the quality of non structure grid cell, and satisfy the needs of practical analysis.
-
Computer Engineering. 2013, 39(10): 294-296,300.Since the rate control for Multi-view Video Coding(MVC) is not well studied, this paper proposes a rate control algorithm for multi-view video coding based on the quadratic rate distortion model. The proposed algorithm consists of four levels for rate bits control more accurately. It reasonably allocates bit rate among views through the analysis of the coded information. The frame layer allocates bits according to frame complexity and temporal activity. Simulation experimental results show that the proposed algorithm can efficiently implement bit allocation and rate control according to coding parameters.
-
Computer Engineering. 2013, 39(10): 297-300.In the situation that the metadata of file system is distrusted or cannot be trusted, it is difficult to recovery the Oracle data files completely with the traditional method of data recovery. Rather than rely on the metadata of file system, Oracle control file and log file information, the file carving based on the characteristics of the Oracle data files’ internal structure is realized. File carving strategies like ideas parallel unique path, bi-fragment gap carving, entropy and so on are adopted to detect the fragment of Oracle data files. It proposes a file caving algorithm based on the keywords of the file header and file addresses. Experimental results show that this algorithm can also extract Oracle data files effectively with no metadata of file system while it gets rid of the traditional data recovery dependences on the metadata of file system.
-
Computer Engineering. 2013, 39(10): 301-304.With the rapid development of unstructured Peer-to-Peer(P2P) network, there exists a lot of free-riding node problems. A kind of file replication algorithm is proposed. In this algorithm, many popular files are copied into nodes including the free-riders to increase the redundancy of files. When the operation of file replication is completed, all target nodes update their contribution values. The simulation experimental result shows that this algorithm not only can effectively force free-riders to take part in resource sharing, but also increase the distribution of the files and the hit rate of queries in unstructured P2P network. So it achieves the purpose of suppressing the free-riding.
-
Computer Engineering. 2013, 39(10): 305-308.Since real-time obstacle avoidance is a key part of mobile robot autonomous navigation, an autonomous mobile robot obstacle avoidance system based on optical flow is proposed. This system’s input is the image sequence grabbed by the camera on the robot in motion. The optical flow information is extracted by Pyramid Lucas-Kanade method to calculate focus of expansion and time to contact. The possible position of the obstacle is estimated with improved balance strategy. Experimental results show that this system can detect and avoid obstacles with the width larger than 10 centimeters but not cover the camera view correctly, which validates the method’s feasibility.
-
Computer Engineering. 2013, 39(10): 309-312.This paper proposes an automatic extraction method based on Document Object Model(DOM) tree and visual features for Web information to extract businesses information in list pages of life information websites. By analyzing and using DOM tree and visual features of data regions in list pages, the method can get the candidate target data regions firstly. The method identifies the target data region by making use of visual features and extracts data records finally. The method tests ten life information websites and achieves 100% recall and 100% precision on eight websites. The results show that the proposed method can get better results.
-
Computer Engineering. 2013, 39(10): 313-316.In accordance with the shortcoming of the Stochastic Petri Nets(SPN) that the fuzziness in the measuring process of time parameters in manufacturing systems cannot be described, the method of system performance evaluation using SPN with fuzzy parameters is proposed to model and analyze the Flexible Manufacturing System(FMS). The DENFORD FMS is set as an example and its main performance indexes are evaluated with fuzzy parameters. The evaluation results of which are also compared with those of the common SPN and the results show that this method can evaluate the comprehensive performance of manufacturing systems more precisely.
-
Computer Engineering. 2013, 39(10): 317-320.In order to develop the intelligent transportation system, this paper presents an extended car-following model called Multiple Information(MI) model based on Multiple Velocity Difference(MVD) model. It attempts to enhance the stability of the traffic flow by using the acceleration and the velocity differences of multiple vehicles. It can be found that the critical value of the sensitivity in MI model decreases and the stable region is apparently enlarged, compared with MVD model. Simulations are made repeatedly, in which the driver’s sensitivity is different value. Results show that MI model is more realistic than traditional ones, and can better describe the dynamics and complexity of traffic flow.
2025
Volume 51 No 6
Volume 51 No 6
(Started in 1975, Monthly)
Superintended by:
China Electronics Technology Group Corporation
Sponsored by：
East-China Institute of Computer Technology
Shanghai Computer Society
Edited & Published by：
Editorial Office 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
Superintended by:
China Electronics Technology Group Corporation
Sponsored by：
East-China Institute of Computer Technology
Shanghai Computer Society
Edited & Published by：
Editorial Office 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