15 December 2018, Volume 44 Issue 12
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Computer Engineering. 2018, 44(12): 1-5. https://doi.org/10.19678/j.issn.1000-3428.0051595
For the one-dimensional Bose-Hubbard theoretical model of condensed matter,the quantum phase transition process of the superfluid-Mott insulation state in the one-dimensional Bose-Hubbard model is realized by continuously changing the depth of the optical lattice well and preparing the temperature of the quantum gas.Through the ultra-cold atomic Time of Flight(TOF) imaging method,the interference pattern of the momentum space of the quantum gas in the diffusion process is analyzed,and the change data of the superfluid component and the Mott insulation state component in the quantum phase transition process are obtained.Experimental results show that the quantum gas in the optical lattice can simulate the one-dimensional Bose-Hubbard theoretical model.
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Computer Engineering. 2018, 44(12): 6-12. https://doi.org/10.19678/j.issn.1000-3428.0051857
To explore the implementation status of multi-bit quantum algorithm in quantum chips and simulators,Grover search algorithm,quantum random walk algorithm and quantum Fourier transform algorithm are run on IBM quantum chips and simulators respectively.For 2 bit Grover search algorithm and 2 bit quantum random walk algorithm,the influence of measurement times on operation results is analyzed and the maximum number of simulation times is selected to compare the operation results of quantum chip and simulator.A 5 bit quantum Fourier transform algorithm and a 3 bit Grover search algorithm are designed and run,and the IBM Q simulator is used to simulate the maximum number of times respectively.Experimental results show that the quantum chip test results are not optimized with the increase of the number of measurements,and the accuracy of the simulation results is obviously better than that of the quantum chip.
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Computer Engineering. 2018, 44(12): 13-17. https://doi.org/10.19678/j.issn.1000-3428.0051966
In the future quantum computing era,there will be security risks in the authentication and key exchange links of constructing Virtual Private Network(VPN).Therefore,a VPN enhanced security architecture based on Quantum Secure Key Management Service(QS-KMS) is established to implement quantum security solutions based on quantum cryptography.A global unified backend QS-KMS service is used to provide authentication and session key for IPSec VPN to decouple VPN services from physical layer quantum devices.In view of the complex working conditions and strong environmental interference of power overhead fiber optic cables,the QS-KMS key pool dynamic key management technology and post-quantum cryptography technology are applied to keep the key pool sufficient to ensure the stable operation of VPN.On this basis,the effective quantum security VPN service in the power communication network is realized.Test results show that this method can meet the needs of power grid control communication.
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Computer Engineering. 2018, 44(12): 18-22. https://doi.org/10.19678/j.issn.1000-3428.0051694
In order to reduce the influence of noise on the efficiency of secret information transmission,a quantum steganographic protocol based on Improved Bostrm-Felbinger protocol(IBF) is proposed.The protocol effectively utilizes the characteristics of quantum entanglement and realizes secret information transmission by Controlled non gate(CNOT gate).Among them,the particle embedded with secret information is used as the initial particle of carrier protocol to transmit secret information while executing carrier protocol steps.Analysis results show that the protocol has better anti-noise robustness,concealment and security.
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Computer Engineering. 2018, 44(12): 23-27,32. https://doi.org/10.19678/j.issn.1000-3428.0051106
In view of the lack of effective coding schemes for quantum zero-error channel,based on the characteristics of quantum five-symbol confusion channel model and the theory of matrix theory,a coding method of five-symbol confusion channel combining quantum superposition state zero-error coding is proposed.In order to improve the channel capacity and reduce the algorithm complexity,zero-error coding is performed by using the isomorphism relationship between quantum superposition states and vectors and between channels and matrices.Analysis results show that this method has higher channel capacity and coding efficiency than the classical confusion channel coding method.
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Computer Engineering. 2018, 44(12): 28-32. https://doi.org/10.19678/j.issn.1000-3428.0052199
The research status of quantum communication at home and abroad is discussed.The problem of quantum non-locality and quantum communication complexity is studied.The GHZ problem is solved by entangled particles,and the minimum number of transmitted bits is discussed by using distributed algorithm.The relationship between non-locality and communication complexity is analyzed,and then the simultaneous message passing model is studied.The results show that compared with the classical communication,the quantum communication efficiency is high,and the quantum non-locality problem and the quantum communication complexity problem can be mutually converted.
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Computer Engineering. 2018, 44(12): 33-38,45. https://doi.org/10.19678/j.issn.1000-3428.0051917
Superconducting quantum computers have the advantages of mature chip processing technology,high system integration,and good scalability.However,superconducting quantum computing needs to increase the quantum integration of chips and ensure decoherence time of quantum chips to achieve fault-tolerant quantum computing.The advancement of superconducting quantum chips is analyzed,and the physical mechanism,advantages and disadvantages of superconducting quantum bus are presented,and several basic quantum bits characteristics are studied.The coupling scheme is discussed between superconducting qubits,including local and non-local coupling.Analysis results on mainstream expansion and layout schemes in recent years show that quantum algorithm programming is suitable for one-dimensional or two-dimensional arrays,while maximum entanglement and full coupling use wraparound expansion schemes to achieve large-scale,high-efficiency quantum to provied an idea for the design of the computational chip.
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Computer Engineering. 2018, 44(12): 39-45. https://doi.org/10.19678/j.issn.1000-3428.0051383
Information security risk assessment is a process of comprehensive evaluation of uncertain and random potential risks in order to effectively suppress and transfer systemic risks.On the basis of analyzing the security elements and security system of information system,the information security risk assessment model based on information assets is constructed.Through the risk assessment index system,the attributes of the evaluation objects actually are obtained.The neural network model is constructed by using a set of quantum gate circurit.The normalized processing result of the attribute samples of the evaluation object is used as the network input and expressed by the quantum bit.The phase rotation is performed by the quantum revolving gate and the quenching of the quantum bit is controlled.After being processed by the network,the comprehensive risk of the evaluated object is obtained.The experimental results show that compared with the traditional BP neural network,this method can realize the risk assessment of information systems,with better convergence performance and more accurate risk prediction ability,which can provide a reliable theoretical basis for risk management.
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Computer Engineering. 2018, 44(12): 46-55. https://doi.org/10.19678/j.issn.1000-3428.0050299
Establishing a hierarchical failure model based on system fault data helps to optimize checkpoints,and improves system availability,and addresses the reliability challenges of future Exascale computing.Taking Sunway TaihuLight as the research subject,the fault collection,classification and processing mechanism are introduced.Based on the actual fault data,a multi-layer failure model including fine-grained failure distribution model and application-level failure model is established to quantify the reliability of the application operating environment.Based on the model,the adaptive checkpoint fault-tolerant optimization model is analyzed to provide theoretical and engineering basis for checkpoint optimization.Taking Sunway TaihuLight as an example,the fault-tolerant optimization analysis result of checkpoints shows that data-driven adaptive fault-tolerant model can effectively reduce system checkpoint overhead.
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Computer Engineering. 2018, 44(12): 56-61. https://doi.org/10.19678/j.issn.1000-3428.0048896
Incomplete logs mining can not represent the potential relationship between activities correctly because there are fewer traces in the logs.To solve this problem,an indirect relation representation is introduced and a mining algorithm for block concurrent process models is proposed.According to the location of the activity in the hierarchical tree,the potential causal follower relationship is found and the correct set of causal follower relationship is obtained,thus the block concurrent process model is excavated.Experimental results show that compared with α‖ algorithm and IM algorithm,this algorithm has higher accuracy,lower complexity and more concise mining results when dealing with concurrent complete logs.
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Computer Engineering. 2018, 44(12): 62-67. https://doi.org/10.19678/j.issn.1000-3428.0050021
In a periodic real-time system scheduled with the Earliest Deadline First (EDF) algorithm,it is necessary to compress some current tasks to avoid overloading if new task requests to run.Compressing a task means that its period is prolonged while its computation time keeps unchanged.An interesting problem is to find the earliest time to release new tasks without any deadline missing,that is,the earliest smooth insertion time.In this paper,a general frame to calculate the earliest time with multiple rounds of deadline checking is given,which shows that the checking can be done from the request time of the new tasks.A smart way is provided and proved,which takes the value of the Δ checking of the current round as the time step to the next.These techniques potentially reduce the amount of the calculation and the number of the rounds of the checking to get the earliest time.Simulation results are also given to support the conclusion.
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Computer Engineering. 2018, 44(12): 68-73. https://doi.org/10.19678/j.issn.1000-3428.0048776
Aiming at the shortcomings of traditional ant colony algorithm,such as long initial pheromone accumulation time and easy to fall into local optimum,an improved ant colony system based cloud service composition algorithm is proposed under the condition of satisfying users’ global Quality of Service(QoS) constraints.The initial pheromone distribution of the ant colony system is obtained by the idea of Genetic Algorithm(GA).The ant optimization path is improved through the learning method of social cognitive optimization algorithm,and the algorithm search efficiency is improved by adopting the optimized ant colony pheromone update strategy.Experimental results show that the improved ant colony optimization algorithm has higher search performance in solving cloud service composition problems.
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Computer Engineering. 2018, 44(12): 74-78,84. https://doi.org/10.19678/j.issn.1000-3428.0049484
Aiming at the problem that the current cloud architecture network can not deal with the diversity of data transmission in cloud network and the requirements of fine-grained and deterministic traffic control,a high-deterministic traffic control method based on Software Defined Network(SDN) is proposed.It combines the advantages of centralized optimization control of SDN and the awareness of the whole network with the multi-queue scheduling mechanism on the switch,and plans the optimal path of the service flow based on the topology and traffic information of the whole network,and allocates a reasonable queue scheduling parameters for the switch,and uses DCTCP to reduce network congestion and ensures bandwidth and delay of various services.At the same time,the full programmable switch is used to implement the fine-grained management of the service flow,and the personalized flow table delivery mechanism is used to dynamically adjust the service transmission bandwidth and service flow level.Experiment result shows that the critical business flow of this method achieves the average queueing delay less than 2 ms,the queueing delay jitter is less than 10 ms,and the packet loss rate is less than 10-6,it can realizes the centralized,real-time and fine management of the traffic flow in the cloud network.
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Computer Engineering. 2018, 44(12): 79-84. https://doi.org/10.19678/j.issn.1000-3428.0049259
The Eclat algorithm uses vertical data representation and does not require complex data structures.However,the intersection count generation mode causes a large amount of memory consumption and low mining efficiency in the process of mining frequent itemsets.Therefore,based on the analysis of Eclat algorithm and its existing improved algorithm,a CPU parallelization Eclat algorithm for bit storing Transaction identifier(Tid) is proposed.The algorithm uses the binary bit form to store the Tid of the project,and distributes the tasks of mining frequent itemsets to each thread of the CPU,maximizing the computing performance of the CPU.Experimental results show that the algorithm can improve the mining efficiency of frequent itemsets while reducing memory usage.
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Computer Engineering. 2018, 44(12): 85-93,101. https://doi.org/10.19678/j.issn.1000-3428.0048505
Most of the supply chain control systems adopt a centralized design,and the system load ceiling is severely constrained by the performance of the central server,resulting in the entire supply chain not flowing properly.Therefore,a scheme combining blockchain,Bitcoin protocol deterministic layered wallet and multi-signature technology is proposed to meet the requirements of product coding,rights management,property transfer,product traceability and anti-counterfeiting verification in the supply chain.The internal entities of the supply chain are divided into "personal entities""product entities" and "right entities",and the entity key is allocated by using the layered wallet technology.The tree structure coding system based on layered wallet technology is given,and the mechanism of decentralized right management and property transfer information recording and verification based on blockchain transaction is designed.Analysis results show that the scheme has the characteristics of blockchain decentralization,transaction traceability and non-tamperability,which can solve common problems in existing technologies and systems,and has greater advantages compared with traditional supply chain control schemes.
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Computer Engineering. 2018, 44(12): 94-101. https://doi.org/10.19678/j.issn.1000-3428.0049104
Aiming at the security vulnerability problem of Hadoop platform,this paper analyzes the present security situation of Hadoop platform,puts forward the remaining security hidden trouble,and designs and implements the relevant reinforcement scheme.By integrating the Hadoop authentication system with the highly available enterprise identity management system,the user and authority information of the enterprise security system is unified and the authentication efficiency is improved effectively.At the same time,the field-level access control strategy is enabled to enhance the flexibility of data management.The health evaluation system based on cluster resources is established to control the health status of the cluster,which can guarantee the safe operation of the whole Hadoop cluster.Experimental results show that this scheme is feasible and effective.
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Computer Engineering. 2018, 44(12): 102-107,114. https://doi.org/10.19678/j.issn.1000-3428.0048921
In order to accurately measure the complexity of software,this paper proposes a calculation method of ring complexity.With the help of McCabe metric method,aiming at C language program,by preprocessing the source program,the key statements which contain the control flow information is extracted.The key sentences are processed separately so as to realize the automatic calculation of program ring complexity,and do not need to use the Control Flow Graph(CFG).Experimental results show that the method is feasible and can calculate the ring complexity of the program accurately and efficiently.
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Computer Engineering. 2018, 44(12): 108-114. https://doi.org/10.19678/j.issn.1000-3428.0048789
Aiming at the loan default behavior on the Internet financial platform,combining the canonical correlation analysis model and the complex network feature extraction method,the quantitative model of default risk is established,and the ROC curve and AUC value are used to evaluate the effect of the model.The model is applied to the actual transaction data of an Internet lending platform and compared with the decision tree model.Results show that the proposed model can effectively reflect the correlation effect between user default features and complex network features,the AUC value of the model can reach about 0.85,and it has stronger stability and robustness.
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Computer Engineering. 2018, 44(12): 115-119,128. https://doi.org/10.19678/j.issn.1000-3428.0048722
Aiming at the inadequate of workflow schedulability and correction strategy under timing constraint,a schedulability analysis method of Mission Critical System(MCS) based on Timing Constraint Colored Petri Net(TCCP-Net) is proposed.It is divided into mission-critical and non-critical tasks based on the nature of the tasks in the system.The activities of the workflow can be scheduled to verify,for non-scheduled activities,combined with the task category and timing constraint to amend it.Example analysis shows that the method has good performance and effect,and has some application value to the description and modeling of the MCS under timing constraint.
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Computer Engineering. 2018, 44(12): 120-128. https://doi.org/10.19678/j.issn.1000-3428.0049260
The STP system is based on data-transmission radio.By the data transmission between the mobile equipment and the ground equipment,it can realize the real-time monitoring of train signal,which is used to ensure the safety protection of the train.To make sure that the information,which transmits by wireless to be real-time,reliable and complete,this paper designs a safety communication protocol for STP.According to En50159,it adds some extra safety measures,such as time-out,sequence-number and so on in STP safe communication protocol,which is based on EuroRadio,to ensure the communication system to be fail-safe.And it uses hierarchical Colored Petri Net(CPN) and ASK-CTL formula to build hierarchy models and make formal verification of the proposed protocol.Analysis results show that the proposed protocol for STP has the functional safety,and it also can be fail-safe,even though the transmission happens during the undesired channel.
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Computer Engineering. 2018, 44(12): 129-133,139. https://doi.org/10.19678/j.issn.1000-3428.0049062
The spacetime of the node is neglected when the mobile sensing node is chosen in mobile Internet.Aiming at this problem,based on the use of mobile sensing nodes instead of fixed sensing nodes as the sensing devices,this paper proposes a mobile node selection algorithm to study the node selection in mobile Internet.The selection algorithm is divided into two steps.Firstly,the algorithm gives a trajectory prediction of the detection node in one period according to its historical movement trajectory.And then it selects the optimal set of participants according to the relevance of the mobile sensing node trajectory association.The simulation results show that,compared with the partial-period participation sensing selection algorithm and the random node selection algorithm,the proposed algorithm has the largest coverage when the number of sensing nodes is the same.The algorithm can be applied to the field of carbon detection to improve the coverage.
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Computer Engineering. 2018, 44(12): 134-139. https://doi.org/10.19678/j.issn.1000-3428.0048641
Aiming at the shortcomings of traditional underwater positioning algorithms,such as small coverage,large calculation of underwater nodes and low positioning accuracy,this paper proposes a hybrid location and optimization algorithm for underwater wireless sensor networks.Based on the Round-trip Time of Flight (RTOF),this algorithm uses the Underwater Sensor Positioning (USP) algorithm to locate the nodes,and uses the weighted iterative least square method to fit and optimize the node position set.The NS2 simulation results show that the optimized algorithm can improve the positioning coverage and positioning accuracy and extend the network lifetime while reducing the traffic,calculation and energy consumption of the underwater nodes.
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Computer Engineering. 2018, 44(12): 140-144,149. https://doi.org/10.19678/j.issn.1000-3428.0048862
The backup path of current routeing protection scheme has a high degree of crossover with the default path.To find two paths with low crossover,the default path may not utilize the shortest path.Therefore,a new intra-domain routing protection scheme is proposed.The problem is described as an integer programming model.The Genetic Algorithm(GA) is used to calculate the approximate optimal solution.The algorithm is simulated on a large number of topologies.Experimental results show that the scheme greatly reduces the crossover between the default path and the backup path,and improves the reliability of the network,and the user experience has improvement.
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Computer Engineering. 2018, 44(12): 145-149. https://doi.org/10.19678/j.issn.1000-3428.0048121
When Wireless Body Area Network(WBAN)is applied,one of the key issues is the selection of appropriate sensor node in each time slot to maximize the network lifetime.The factors that determine the lifetime of WBAN with relays are investigated,in the case of energy limitation.From the point of view of the main node and the whole network,two definitions of network lifetime are given.Meanwhile,four relay selection strategies are proposed based on the channel state information and the residual energy of nodes.Simulation results show that the second definition of network lifetime makes full use of the sensor nodes energy resource,and the strategy which selects the maximum sum of the two-hop channel gains can make the network lifetime reach global optimum.
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Computer Engineering. 2018, 44(12): 150-155,162. https://doi.org/10.19678/j.issn.1000-3428.0048730
Aiming at the problem that the existing under water acoustic sensor network non-uniform clustering routing protocol consumes too much energy in the clustering and inter-cluster data transmitting phase,a solution to the unequal clustering and inter-cluster routing energy optimization is designed.The threshold formula is set according to the remaining energy of the node,the interval to the base station and the energy consumption factor,and the electoral cluster head is optimized and the weight of the node cluster is considered to effectively balance the node energy loss.An improved ant colony algorithm is introduced in the inter-cluster data transmitting stage.The energy,spacing and hop count of the cluster nodes are considered by the heuristic function,and the percentage of remaining energy is added to the pheromone concentration to balance the energy consumption of the cluster head.Experimental results show that compared with the classical LEACH,EEUC and EEMUC algorithm,the algorithm reduces the energy loss and extends the life cycle of the network as a whole.
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Computer Engineering. 2018, 44(12): 156-162. https://doi.org/10.19678/j.issn.1000-3428.0049337
Aiming at the problem of unequal distribution of energy consumption of nodes during the operation of Wireless Sensor Network(WSN),an energy consumption balance clustering protocol based on game theory is proposed.Combined with the residual energy of the node to define the node income and loss,the two rounds of cluster head election mechanism and the penalty function are introduced to prevent the infinite iteration of the cluster head election.The nodes get the equilibrium probability of maximizing the node’s revenue through game theory.An iterative algorithm is presented to select the real cluster heads from the candidate cluster heads according to the residual energy and loss of the nodes.Simulation results show that,this protocol can effectively balance the node energy consumption and extend the network lifetime.
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Computer Engineering. 2018, 44(12): 163-167. https://doi.org/10.19678/j.issn.1000-3428.0049471
Aiming at the problem that it is difficult to determine the row offset of the S-box elements for the Cache timing attack using the Flush+Reload method on Data Encryption Standard(DES) algorithm,a method is proposed to determine the row offset by using the property that S-box will be misaligned in the Cache.To evict S-box information of the DES algorithm from the Cache,the attack uses the clflush instruction to flush cache line.When the DES algorithm queries the S-box,it leaks the information of Cache timing.The intermediate state value which equals the plaintext and key XOR is recovered by utilizing this leaked information.Utilizing the value and the known plaintext,the key of DES is recovered.Experimental results show that this method can determine the row offset of S-box elements and improve the efficiency of Cache timing attack against DES algorithm.
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Computer Engineering. 2018, 44(12): 168-172. https://doi.org/10.19678/j.issn.1000-3428.0049025
Most of the existing physical layer encryption algorithms setting and security analysis are carried out on baseband,ignoring the threat of spectrum leakage to the security of the algorithm.On the basis of analyzing the spectrum characteristics of Orthogonal Frequency Division Multiplexing(OFDM)signal,a spectrum analysis attack method is designed.By establishing a one-to-one correspondence between the information or key symbol and the frequency component of the ciphertext spectrum,the information,key and modulation mode can be obtained.The example analysis and simulation results show that the method has good effect on the M-OFDM algorithm with different parameters and can recognize the information symbols correctly.
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Computer Engineering. 2018, 44(12): 173-177,183. https://doi.org/10.19678/j.issn.1000-3428.0048204
In order to solve the problem that the existing information flow model is too strict to determine the dynamic trusted of system,a dynamic Intransitive Noninterference(INI) model based on iP-observability attribute checking is proposed.It abstracts the system into a six-tuple,which introduces the iP-observability attribute from the noninterference theory,the observability of system states and system states’ influencing factors,and transforms the iP-observability into P-observability attribute in automatic machine by automatic machine model,and then uses the P-observability attribute checking algorithm to reverse that the original system can meet the Dynamic INI(DINI) theory.Finally,an example of the corresponding abstract system is given to illustrate the effectiveness of the model.
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Computer Engineering. 2018, 44(12): 178-183. https://doi.org/10.19678/j.issn.1000-3428.0049237
Information security risk assessment is a process that needs to deal with a lot of fuzzy information.In order to increase the accuracy of information processing,an information security risk assessment method based on three-parameter interval and information entropy is proposed.After the analysis of the information system,the evaluation matrix of the three-parameter interval of risk factors is established,and the weight of risk factors is determined according to the information entropy theory.Expert weights are obtained using the theory of interval distance and interval order.The final assessment result is obtained by aggregating three factors.An example is presented to assess risk using the proposed method.Expenmental results show that compared with the two interval,the proposed method can predict risk levels more accurately.
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Computer Engineering. 2018, 44(12): 184-189,195. https://doi.org/10.19678/j.issn.1000-3428.0047965
This paper studies the abnormal behavior of Fast-Flux based on Domain Name System (DNS) packets,analyzes the working characteristics of botnets,learn the attack characteristics of Fast-Flux based on the data of a large number of DNS packets,and finds out the specific characteristics of Fast-Flux attacks.It identifies anomalous data in DNS traffic.Through comprehensive analysis of DNS data,it distinguishes between Fast-Flux and large IP sites with frequent IP changes,and gives Fast-Flux messages with short Time To Live(TTL),average time difference distribution,frequent requests,IP pool,etc.,and proposes a message screening algorithm.Analysis results show that compared with the traditional botnet detection method,the algorithm is simpler and easier to implement and can exactly the describe the Fast-Fulx attack behavior when the message correct rate is the same situation.
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Computer Engineering. 2018, 44(12): 190-195. https://doi.org/10.19678/j.issn.1000-3428.0049009
Traditional data encryption aggregation schemes in Wireless Sensor Network(WSN) have some shortcomings in security and efficiency,such as ciphertext data operation,resist internal/external attacks,tracking and repairing errors.To solve this problem,a fully homomorphic data encryption aggregation scheme is proposed.DGHV homomorphism algorithm is used to encrypt the privacy data,and the identity information of the node is embedded in the digital signature,so that the scheme has the ability to trace and repair errors.In addition,the scheme does not require a trusted third party,it allocates interference factors in clusters to defend against internal attacks and improve operational efficiency.Experimental results show that the scheme is IND-CPA secure,and it can resist internal/external attacks and satisfy the full homomorphism.
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Computer Engineering. 2018, 44(12): 196-201. https://doi.org/10.19678/j.issn.1000-3428.0050708
At present,the abnormal behavior detection based on video mainly focuses on the single vehicle restricted scene,which is difficult to monitor the whole transport process.Meanwhile,the track analysis of GPS is mainly based on the prior threshold judgment,which lacks the steps of in-depth data analysis and information mining.Aiming at these problems,this paper proposes an abnormal detection method of driving behavior based on GPS data.It uses the global and local features such as time,speed,acceleration,direction and rotation angle and their corresponding statistics,to construct the characteristic attributes of the driving behavior of the vehicle.It clusters and analyzes the existing commercial vehicle trajectory data to get the result of abnormal driving behavior detection,which is based on above features.Experimental results show that this method can accurately determine typical abnormal driving behaviors such as overspeed,rapid acceleration/deceleration and frequent lane change of the vehicle under test.
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Computer Engineering. 2018, 44(12): 202-207,214. https://doi.org/10.19678/j.issn.1000-3428.0049174
High-utility itemset mining algorithm is an important part of association analysis.By improving the basic binary particle swarm optimization algorithm,a Double Binary Particle Swarm Optimization（DBPSO） algorithm is proposed.The minimum utility threshold is determined using the product of the minimum relative utility threshold and the utility upper bound.The candidate subspace is dispersed by the minimum utility threshold and fitness function,and the high-utility itemset is mined.Experimental results show that compared with the UP-Growth algorithm,the algorithm has a faster convergence rate and can mine a higher high-utility itemset.
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Computer Engineering. 2018, 44(12): 208-214. https://doi.org/10.19678/j.issn.1000-3428.0049046
Taking mobile robot navigation as the research object,an online global path planning and tracking algorithm in cluttered environment is proposed.Using the graphical user interface to study the path length,running time and stability of the algorithm,A* algorithm is chosen as the global path planning algorithm in cluttered environment.By establishing a kinematics model and tracking error model of the mobile robot with non-holonomic constraints,the improved adaptive trajectory tracking control is used to effectively track the A* algorithm motion trajectory.Experimental results show that the graphical user interface can select the optimal global planning algorithm from the cluttered map,and the robot can avoid obstacles in a timely and effective way in the trajectory tracking process.
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Computer Engineering. 2018, 44(12): 215-221,227. https://doi.org/10.19678/j.issn.1000-3428.0051163
To improve the accuracy of view based 3D model classification algorithms,a 3D model classification algorithm based on multiple local salient views and Convolutional Neural Network(CNN) is proposed in this paper.Firstly,the local views of a 3D model are extracted from multi perspectives.Then,by evaluating the saliency of each extracted view,multiple local salient views are established to form a reasonable representation of the 3D model,which have the fine properties of integrity and diversity.Finally,integrating the single view based CNN,a 3D model classification oriented ensemble deep learning model is proposed by using the bagging strategy,so as to improve the generalization and accuracy of the classifier.Experimental results on ModelNet10 dataset show that this algorithm can effectively improve classification accuracy.
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Computer Engineering. 2018, 44(12): 222-227. https://doi.org/10.19678/j.issn.1000-3428.0049051
In order to improve the detection speed of the Convolutional Neural Network (CNN) target detection algorithm,a target fast detection algorithm based on hybrid structure CNN is proposed.CNN is optimized by CNN-based Faster R-CNN target detection framework.Based on the multilayer perceptron structure,a CR-mlpconv convolutional layer structure is proposed.The C.ReLU strategy is adopted in the shallow layer of the network,and the CR-mlpconv layer structure and the C.ReLU strategy are combined to design the layer parameters reasonably to form CNN.CNN is merged into the Faster R-CNN detection framework to achieve rapid target detection.Experimental results show that compared with the Faster R-CNN+ZFnet algorithm,the algorithm can reduce the network model parameters,reduce the memory consumption of the network model,and improve the real-time performance of the network.
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Computer Engineering. 2018, 44(12): 228-232. https://doi.org/10.19678/j.issn.1000-3428.0049053
Virtual soldier combat simulation requires high path planning,but the fireworks algorithm in path planning has a discontinuous path problem.Therefore,an improved fireworks algorithm is proposed.The view method can be used to model the map and transform the path plan into a combination of finding the best path points.By combining the soldier visual model to achieve the judgment of the environmental threat,the insertion and deletion operations of the path node are added to eliminate the discontinuous path,thereby obtaining the path related data.Simulation results show that compared with A* algorithm,the algorithm can reduce the path length and save planning time,and has strong search capability.
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Computer Engineering. 2018, 44(12): 233-239. https://doi.org/10.19678/j.issn.1000-3428.0047936
Most of the visual reconstruction method have problems such as complicated equipment,low precision,and high time consuming.A three-dimensional model method for recovering a scene by a single handheld digital camera is proposed.The camera pose is initialized by the classic epipolar geometry.The improved PnP algorithm is used to calculate the pose in multi-frame images.By selecting new image robust feature points to expand the scene,the accuracy of the scene is improved,and the bundle adjustment method based on local correlation frames is used to optimize the camera pose and 3D point position.Experimental results show that compared with the traditional beam adjustment method,the method can save time effectively and has strong robustness.
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Computer Engineering. 2018, 44(12): 240-246. https://doi.org/10.19678/j.issn.1000-3428.0048480
Convolutional neural networks have some problems of slow parameter adjustment,more iterations,and poor classification of small sample data in the image recognition.Therefore,a method of locally adjusting a Convolutional Neural Network(CNN) is proposed.By adjusting the size of the demand,the neurons corresponding to the parameters are divided into key parts and non-critical parts,and dynamic learning rate and local oritical point correction are used to achieve rapid parameter adjustment.Experimental results on mnist,ORL,CIFAR-10 and LFW show that compared with DAP,UCNN and other algorithms,the local adjustment of the CNN parameters is faster.It has Less time and a higher overall recognition rate under the same recognition accuracy in image recognition.
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Computer Engineering. 2018, 44(12): 247-250,257. https://doi.org/10.19678/j.issn.1000-3428.0049018
In order to solve the problems of large computation and color distortion of high dynamic range imaging algorithm based on RGB color space,a high dynamic range imaging synthesis algorithm based on L*a*b* color space is proposed.A series of images with different exposures are converted from RGB color space to L*a*b* color space.Debevec-Malik algorithm is used to process the images on L* channel.The camera response curve is obtained and the luminance component is synthesized to obtain the luminance image of the high dynamic range image.Two colorimetric images with high dynamic range are obtained by weighted average synthesis of a* and b* chromaticity channels respectively.The luminance channel of the synthesized high dynamic range image is tonal mapped and converted to RGB color space for display.Experimental results show that,compared with the synthesis algorithm based on RGB color space and YUV color space,the high dynamic range image synthesized by this algorithm has higher quality and faster computation speed.
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Computer Engineering. 2018, 44(12): 251-257. https://doi.org/10.19678/j.issn.1000-3428.0049039
To solve the problem that gray blurring and variation cause low recognition rate and poor accuracy for trajectory tracking and trajectory tracking,the processing of gray-scale enhancement,pixel feature conversion and pixel point connectivity of laser scattering image is completed by the analysis of the dynamic gradation changes caused by the individual shape,motion shape and spatial motion of the settled particles.A settlement particle recognition strategy based on Haar-PP mixed feature is proposed.Experimental results show that compared with the Gaussian mixed model,the algorithm has higher recognition rate and lower time complexity.
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Computer Engineering. 2018, 44(12): 258-263,270. https://doi.org/10.19678/j.issn.1000-3428.0050056
Multimodal Magnetic Resonance Imaging(MRI) brain tumors image has many defects,such as uneven gray level,diverse tissue types,which lead to the difficulty and low accuracy of brain tumors segmentation,and most of the existing brain tumors segmentation algorithms are semi-automatic segmentation algorithms.To solve this problem,an end-to-end automatic brain tumors segmentation model is established.A large number of two-dimensional slice images are obtained by slicing the three-dimensional images of brain tumors.The slice images of the training set are normalized and then directly input into the segmentation model.The brain glioma region is correctly segmented by the trained model.The segmentation of the model is evaluated by Dice coefficient,sensitivity coefficient and Positive Predictive Value(PPV) coefficient.Experimental results show that the proposed model is easy to operate and has good robustness,the three evaluation indexes can reach 0.94,0.92 and 0.97 respectively.
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Computer Engineering. 2018, 44(12): 264-270. https://doi.org/10.19678/j.issn.1000-3428.0049136
Feature extraction is one of the most important steps in correlation filtering based on tracker algorithm,but existing feature extraction methods do not take into account the effects of feature optimization and feature fusion.As the tracking performance under linear kernel can directly reflect the characteristics of feature description,two criteria which are OTB and VOT are used to evaluate the description capability and complementarity of grayscale,shape,texture and color features in multiple tracking scenarios.The applicability and complementarity of each feature in various tracking scenarios are analyzed,which provides theoretical and experimental basis for single feature selection or multi-feature fusion in tracking algorithm.Expenmental results conducted show that shape,texture and color features can complement each other in complex scenes.
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Computer Engineering. 2018, 44(12): 271-275,287. https://doi.org/10.19678/j.issn.1000-3428.0049178
In order to make full use of the video-wide temporal information and reduce the redundant frames and dimensions of features,a method of extracting valid video frames and performing temporal rank pooling for human action recognition is proposed.Vector of Locally Aggregated Descriptors(VLAD) is used to encode dense trajectory features of every frame of video to get feature representations.The cosine similarity analysis of frame features is employed to remove the redundant features and extract feature sequence of valid video frames.Temporal rank pooling is performed to order feature sequence of valid frames temporally and get the feature vectors capturing the evolution of video-wide temporal information.Support Vector Machine(SVM) is learned to get the results of human action recognition.Experimental results conducted on HMDB51 and UCF101 datasets show that compared with the dense trajectory recognition algorithm,the proposed agorithm has improved the recognition accuracy.
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Computer Engineering. 2018, 44(12): 276-280. https://doi.org/10.19678/j.issn.1000-3428.0049175
The highly dynamic topology of the Vehicular Ad-hoc Network (VANET) makes the frequent network segmentation.To solve this problem,A new compatible Road Side Unit(RSU) deployment scheme is proposed which based on taxi GPS data in real city environment.Firstly,an RSU deployment strategy based on regional connectivity is put forward to improve the connectivity of VANET in urban environment which the traffic distribution is uneven.Secondly,the Markov clustering algorithm is used to detect the hotspots in urban road network.Finally,a compatible RSU deployment scheme integrated regional connectivity and hotspot area is presented.The simulation experiment is carried out based on the real taxi GPS trajectory data.The results show that the proposed algorithm can effectively improve the connectivity of VANET in urban environment.
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Computer Engineering. 2018, 44(12): 281-287. https://doi.org/10.19678/j.issn.1000-3428.0047985
At present,text information extraction and retrieval cannot adapt to the complex environment,limited by user rights and facing the problem of large storage capacity.Based on the feature analysis of all kinds of document text information,a parallel depth text information analysis system is established.Text information is extracted from different types of documents based on fine-grained expression of XML,and the text information extracted by keyword retrieval is retrieved by parallel technology based on multi-core.Finally,the result of information analysis is outputted.The experimental results show that the system can analyze the different types of text information in fine granularity and extract the complete information quickly when the number of keywords is large.
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Computer Engineering. 2018, 44(12): 288-293,300. https://doi.org/10.19678/j.issn.1000-3428.0050187
The tradition encryption algorithms make the cloud server fail to parse the encrypted data and limit the data processing capability of the cloud platform.A new order-preserving encryption based on coding tree is proposed.The order-preserving ciphertext is generated according to the search path of the ciphertext in the coding tree.Because of the ciphertext variability,an update strategy is designed to quickly perform ciphertext updates when data is updated,so as to ensure the efficiency and reliability of encryption algorithm.Experimental results show that the algorithm can reduce the number of client-server communication and greatly improves the efficiency of generating ciphertext.
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Computer Engineering. 2018, 44(12): 294-300. https://doi.org/10.19678/j.issn.1000-3428.0048908
The traditional collaborative filtering recommendation algorithms have the problems of data sparsity and cold start of users.Although the recommendation algorithms based on trust mechanism can alleviate the problem of data sparsity,but the time cost is large in the process of trust propagation.Aiming at this problem,a recommendation algorithm based on user comprehensive trust and community trust propagation is proposed in this paper.The trust model of this algorithm is used to obtain comprehensive trust which is brought into collaborative filtering algorithm to get the recommendation results.The proposed algorithm considers two direct trust of explicit and implicit,and gets direct comprehensive trust which is used to build trust network of users.Private virtual community for users is divided by using the overlapping community discovery algorithm,and trust propagation is carried out in the user private virtual community to compensate for the lack of direct comprehensive trust.The experimental result on Epinions data set shows that this algorithm can effectively alleviate the data sparsity and cold start of users,meanwhile reducing the time cost of trust propagation and improving the quality of recommendation.
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Computer Engineering. 2018, 44(12): 301-315. https://doi.org/10.19678/j.issn.1000-3428.0048674
Under the globalization background,cultural diversity is facing serious challenges,constructing a computational test model to explore the protection mechanism of cultural diversity is very important.So this paper uses Agent-based micro modeling method and social circles theory to construct a more realistic dynamic social network of culture.Agent’s cultural transmission in the network considers the individual’s cultural openness and tolerance,the cultural status,the stability of the cultural integration and the attraction of the bicultural to the single culture.This model mainly reflects the cultural consciousness and the link role of bicultural plays an important role in the social culture system,which guides the system from the state of assimilation or opposition to the state of integration.It gives the new policy regulation ideas for the protection and development of cultural diversity.Simulation results show that this model can simulate the evolution of cultural territory comprehensively,such as cultural assimilation,cultural opposition and the integration of different cultures,and provide a virtual method and computational experiment platform for the further study of the rule of cultural evolution and the mechanism of policy regulation in future.
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Computer Engineering. 2018, 44(12): 316-320. https://doi.org/10.19678/j.issn.1000-3428.0049038
The traditional recommendation algorithms which rely on similarity measurement and nearest neighbor retrieval have the problems of large computation and low recommendation efficiency in the face of massive high-dimensional data.To deal with the problem,a Two-stage Joint Hashing(TSH) collaborative filtering algorithm based on user and item perspective is proposed.Principal Component Analysis (PCA) and iterative quantization techniques are applied to generate binary codes for rating data from user or item perspective.Then the binary code of another perspective is generated by constraining the Haming distance of user and item,and the recommendation task based on top-K recommendation is accomplished by the binary code.Experimental results on the MovieLens-1M dataset show that,compared with ITQ and BinMF algorithm,this algorithm can effectively reduce the computational consumption in the recommendation process and improve the recommendation quality.
Volume 50 No 4
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