15 October 2018, Volume 44 Issue 10
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Computer Engineering. 2018, 44(10): 1-5. https://doi.org/10.19678/j.issn.1000-3428.0048451
In order to guarantee the integrity,confidentiality and accessibility of outsourcing data,a secure data outsourcing and sharing scheme is proposed based on the vector commitment primitive and the proxy re-encryption technology.By introducing a digital signature of the commitment value,any third party can verify the integrity of the outsourcing data without the data owner and service provider being fully trusted,and the data owner can perform efficient execution of the outsourcing data adding,deleting,modifing,and accessing authorization actions.Performance and safety analysis results show the feasibility of the scheme.
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Computer Engineering. 2018, 44(10): 6-13. https://doi.org/10.19678/j.issn.1000-3428.0051389
Mimic defense techniques can effectively solve the security problems in real-time systems,but its heterogeneous redundancy will increase the system delay.To solve this problem,based on the architecture of the mimic processor,a hard time and aperiodic tasks fault tolerant scheduling algorithm is proposed in the dynamic heterogeneous multi-mode redundancy scenario,combining the specific voting strategy and implementing the cleaning handover tasks.Simulation results show that compared with the static-heterogeneous-model-based DRFTS algorithm,this algorithm can improve the guarantee ratio under the condition of hard real-time.
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Computer Engineering. 2018, 44(10): 14-21. https://doi.org/10.19678/j.issn.1000-3428.0051296
With the exhaustion of IPv4 addresses,the domestic network has gradually shifts to IPv6 from IPv4,which leads to the rapid expansion of large-scale network traffic based on IPv6.The security risks and attack threats faced by IPv6 networks becomes an urgent problem to be solved in network development.Therefore,in the actual IPv6 network environment,the real-time acquisition of large-scale IPv6 data traffic based on IPv6 dual protocol stack is studied,and traffic classification and anofmaly traffic routine detection are carried out.The k_means network anomaly detection algorithm based on sliding time window is proposed.It designs a network abnormal traffic detection system based on IPv6 protocol,analyzes system performance and gives test results.Experimental results show that the algorithm can effectively detect anomaly traffic in the network and provide a good experimental platform for subsequent research and anomaly detection based on IPv6 network traffic.
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Computer Engineering. 2018, 44(10): 22-27. https://doi.org/10.19678/j.issn.1000-3428. 0051189
In the era of big data,traditional hidden hyperlink detection technology cannot quickly and accurately identify websites that encounter “hidden hyperlink attacks” on massive Web pages.To solve this problem,this paper introduces machine learning to the detection method for hidden hyperlink,which combines the characteristics of hidden hyperlink related texts,hidden hyperlink domains and the hidden structure of hidden hyperlink.The three models are constructed and compared using Classification and Regression Tree (CART),Gradient Boosted Decision Tree (GBDT) and Random Forest (RF).based on the proposed method.Experimental results show that the proposed method has high accuracy and reliability,and the classification accuracy of the detection model constructed by RF can reach 0.984.
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Computer Engineering. 2018, 44(10): 28-33,41. https://doi.org/10.19678/j.issn.1000-3428.0051042
In order to solve the problem of high delay,low efficiency and indistinguishes communication service types in the existing address mutation technology,a service awareness based address mutation method is proposed in the SDN environment.With the feature of subsection IP continuous segmentation,an efficient random address generation algorithm is adopted to make the address mutation technology more efficient.At the same time,a communication authentication algorithm is used to provide different mutation modes according to the architecture and reliability requirements of both sides.Experimental results show that,compared with the OF-RHM and PPAH-SPD method,this method can effectively guarantee the communication parties from the sniffer attack,provide more efficient and flexible address random mutation effect and address mutation mode,reduce the time delay of 30%~60% and reduce the jitter.
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Computer Engineering. 2018, 44(10): 34-41. https://doi.org/10.19678/j.issn.1000-3428.0051222
Aiming at the problem of the failure rate and low detection efficiency in the XSS dynamic detection method,a new XSS vulnerability detection model is proposed.The model is divided into five parts:load cell generation,bypassing rule selection,exploratory load test,load unit combination test and load unit separate test.According to the location and function type of the load unit,the attack load is cut into different types of units,and the rules of combined attack load are formulated.The probe load is used to determine whether there is any vulnerabilities to be detected,it puts the payload unit and the bypassing rules into the detection point with combination test and separate test,and generates attack loads based on the test results.Experimental results show that this model uses fewer test requests to complete the test of more attack loads,and maintains a high detection efficiency while effectively reducing the failure rate.
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Computer Engineering. 2018, 44(10): 42-45,50. https://doi.org/10.19678/j.issn.1000-3428.0051035The main causes of threats to cyberspace security are vulnerabilities and backdoor problems.In order to solve the threats based on unknown vulnerabilities,backdoor or virus Trojans in cyberspace,a probabilistic mathematical model is established for the typical architecture of mimic defense,Dynamic Heterogeneous Redundancy(DHR) system.The security of the system is discussed from the perspective of output consistency rate and system attack success rate.Through the solution and analysis of the model,the expression of the attack success rate of the DHR system is obtained,and some properties of the DHR system are analyzed.Analysis results show that the DHR system has better anti-attack capability than the static heterogeneous redundant system.
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Computer Engineering. 2018, 44(10): 46-50. https://doi.org/10.19678/j.issn.1000-3428.0051085A Botnet that combining worms,backdoors,and Trojans has become the backing of Advanced Persistent Threat(APT) attacks because it can be used by attackers to send spam,perform denial of service attacks,and steal sensitive information.Existing Botnet detection methods are mostly limited to specific Botnet types and cannot effectively process data near the boundary.Therefore,a Botnet identification method based on network traffic similarity is proposed.This method does not rely on packet content and can handle encrypted traffic.By extracting the statistical features of the data stream and the packet,each feature is fuzzy clustered,the feature boundary of the fuzzy category is discriminated,and the Botnet traffic is judged based on the principle of maximum affiliation degree.According to the support degree and confidence degree,associate rules are filtered to determine the specific Botnet type.Experimental results show that the method can effectively identify Botnet traffic and predict the type of Botnet.
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Computer Engineering. 2018, 44(10): 51-57. https://doi.org/10.19678/j.issn.1000-3428.0048139In order to support the application of Fiber Channel(FC) protocol in avionics system and effectively improve the time certainty of message transmission,time triggered mechanism is introduced as message scheduling strategy into FC protocol,and a time triggered FC terminal protocol chip based on FPGA digital logic platform is designed.At the same time,according to the related performance indicators,the main modules of the FC IP kernel,the sending/receiving cache management module and the IRIG-B codec module are designed in detail.Test results show that,the protocol chip port state machine,frame sending and frame receiving module work normally,and the time domain signal waveform is normal,and the data message can be dispatched in turn according to the time schedule table to meet the design requirements.
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Computer Engineering. 2018, 44(10): 58-63. https://doi.org/10.19678/j.issn.1000-3428.0048050In the traditional controller static deployment strategy,the mapping relationship between the controller and the switch is static,causing it to be unable to adapt to the high dynamic topology and network traffic change of the satellite.To solve this problem,a multi-controller dynamic deployment strategy based on Software Defined Network(SDN) is proposed.Considering the periodic changes of topology and the burst of flow,a two threshold switch dynamic transfer method is proposed for the 2 critical states of load overload and under load,which solves the problem of controller failure during the overloading as well as the waste of resources when under load.Simulation results show that,compared with the multi-controller static deployment strategy,the proposed strategy can improve the system throughput,reduce the system response delay,improve the overall network performance and ensure the load balance between the controllers.
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Computer Engineering. 2018, 44(10): 64-68. https://doi.org/10.19678/j.issn.1000-3428.0047859The Cyber Physical System(CPS) can realize the coordination and cooperation between the information process and the physical process.It realizes real-time perception,dynamic control and information service of large-scale engineering system.So this paper puts forward an architecture implementation mode of CPS,focusing on the composition,structure and operation mechanism of the system.The core mechanism of system operation mechanism,named spatio-temporal event model is demonstrated by using formal language.The results show that the formal model time can guarantee the reliability,efficiency and real- time performance.
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Computer Engineering. 2018, 44(10): 69-79. https://doi.org/10.19678/j.issn.1000-3428.0048609R&A and R2W Remote Direct Memory Access Read(RDMA Read) message implementation mechanisms have some shortcomings in design complexity,design overhead and communication performance.To solve this problem,the three existing mechanisms are compared and analyzed from two aspects.In terms of design complexity,the basic hardware implementation flow is designed for the two mechanisms and qualitative analysis is made.In terms of design overhead and communication performance,performance analysis model based method is used to analyze the theory and software verification platform is designed to achieve experimental verification.An improved RDMA Read implementation mechanism is proposed according to the analysis results and the methods and characteristics of the two mechanisms.Experimental results show that compared with R&A and R2W,the improved RDMA Read mechanism performs well and equally in terms of design complexity,design overhead and communication performance.
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Computer Engineering. 2018, 44(10): 80-84. https://doi.org/10.19678/j.issn.1000-3428.0048927For common Linux platforms,the existing peripheral device control methods have the problems that the control factor analysis is one-sided,the control grain size coarse,the control way is not flexible enough,etc.This paper proposes a deductive peripheral Device Control Model(DCM) supporting fine-grained.DCM consists of requirement goal,controlled entity,control object and control strategy.Control object can be layered nested compound object.The control policy provides a set of configuration libraries that cover driver prejudgment,mount permissions,and user access in an extensible manner.On the basis of fine-grained analysis of components of DCM,the formal description and deduction are given.The engineering implementation of the Linux platform confirms its good deduction and practicality.
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Computer Engineering. 2018, 44(10): 85-94,100. https://doi.org/10.19678/j.issn.1000-3428.0048482In order to ensure Hard Real-time Task(HRT) to meet deadlines,their Worst Case Execution Time(WCET) with instruction prefetching need to be analyzed.Although the cache analysis methods with instruction prefetching in single-core have already existed,the researches are limited on the single-level instruction cache and they cannot be applied on the multi-level cache WCET analysis on multi-cores.Through extending instruction prefetching semantic for multi-level cache analysis model based on abstract interpretation,this paper puts forward a cache analysis method with instruction prefetching on the multi-cores model based on set cache partitioning.Experimental results verify the method has high safety and can improve the prefetching cache performance of multi-core HRT.
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Computer Engineering. 2018, 44(10): 95-100. https://doi.org/10.19678/j.issn.1000-3428.0048446Existing methods for program defect repair lack sufficient repair templates,and most of them can only repair a small number of program defects.To solve this problem,a method is proposed to obtain sample code from StackOverflow and to mine repair samples from sample code.From the programmer’s day-to-day development discussions,get the code pairs that are relevant to the fix and generate the fix template,which enriches the existing operations of the automatic fix tool and enables it to fix more defects.Experimental results on Defects4J dataset show that the method can repair 23 program defects,and is superior to GenProg and Nopol.
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Computer Engineering. 2018, 44(10): 101-106. https://doi.org/10.19678/j.issn.1000-3428.0049187In order to enhance the anti-jamming capability of data link in low Signal to Noise Ratio(SNR) environment,this paper improves the energy detection method based on invariable threshold and proposes an adaptive threshold anti-jamming method based on energy detection.By changing the parameters α,the detection probability of the jamming signals under the low SNR environment is improved.According to the proposed adaptive threshold detection method,this paper studies the cognitive anti-jamming method of data link based on cooperative spectrum sensing.Under different parameter settings,it calculates the detection probability of the data link to the jamming signals.Analysis results show that the proposed method can improve detection performance under the low SNR environment.
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Computer Engineering. 2018, 44(10): 107-111. https://doi.org/10.19678/j.issn.1000-3428.0048461In order to estimate the source information of multi-user Wideband Code Division Multiple Access(WCDMA) signals,the multi-user signals are separated by array antenna airspace filtering first,and then the Principal Component Analysis(PCA) combined with the Phase Locked Loop(PLL) technology is used to estimate the source information of different users.In the case of unknown carrier frequency,this method utilizes the frame repetition of WCDMA signal scrambling code and OVSF code superposition sequence to construct a WCDMA signal model of the carrier modulation to perform blind decoding.Simulation results show that the method can effectively and blindly decode the source information of multi-user WCDMA signals.
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Computer Engineering. 2018, 44(10): 112-117. https://doi.org/10.19678/j.issn.1000-3428.0048073Traditional Cognitive Radio-Vehicular Ad-hoc Network(CR-VANET) employs the contention-based Medium Access Control(MAC) protocol.This MAC protocol may lead to high packet collision under high-density of vehicular nodes situation,which makes the transmission delay and affects the reliability of safety messages.To optimize the system performance of CR-VANET,a cooperative MAC protocol based on road segmentation is proposed.The packet collision probability and the transmission delay can be effectively reduced by allocating slots through Cluster Head(CH).Besides,in order to guarantee the validity and reliability of the message transmission,auxiliary nodes are selected in idle slots,which can help to retransmit the message to the node that fail to receive the data packet.Performance analysis and experimantal results show that this protocol can efficiently decrease the packet drop rate and transmission delay,meanwhile improving the network throughput.
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Computer Engineering. 2018, 44(10): 118-123. https://doi.org/10.19678/j.issn.1000-3428.0048311The dynamic multipath is a major challenge to positioning solutions based on Received Signal Strength(RSS) ranging.Aiming at this problem,this paper puts forward Frequency Hopping Received Signal Strength(FHRSS) indoor positioning system.It transfers the ranging signal through the guard band of radio and television,and does the frequency hopping measure between the widely distributed guard bands.Based on the frequency selectivity of multipath,a ranging method is designed to eliminate multipath errors.FHRSS has a simple closed-form expression and hence avoids the training process,which limits the use of traditional RSS method severely.It is implemented with USRP N210 software radio platform and evaluated in a dynamic indoor environment.The experimental results show that,compared with the traditional RSS-based positioning system,FHRSS can reduce the ranging error and the positioning error respectively,and its positioning accuracy reaches 2.6 m.
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Computer Engineering. 2018, 44(10): 124-128. https://doi.org/10.19678/j.issn.1000-3428.0048434In the multi-user detection processes of Sparse Code Multiple Access(SCMA) system,MAX-Log Message Passing Algorithm (MPA) causes partial loss of messages due to the approximate calculation,which makes its detection performance poor.Aiming at the above problem,an improved MAX-Log MPA algorithm is proposed in this paper by introducing an approximate method closing to the true value.In this algorithm,the resource node message update formula multiplies with a constant 2,which can effectively reduce the message loss caused by the approximate calculation of the original MAX-Log MPA,thereby improving the detection performance of the MAX-Log MPA multi-user detector.Theoretical and simulation results show that the improved algorithm can not only maintain the low complexity of the original algorithm,but also obtain better detection performance.
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Computer Engineering. 2018, 44(10): 129-135. https://doi.org/10.19678/j.issn.1000-3428.0047270In order to reduce the cluster sensing network transmissions and prolong network lifetime,this paper proposes a data collection method based on the hybrid Compressive Sensing(CS) technology for clustering Wireless Sensor Network(WSN).It divides the sensing area into several clusters according to the geographical location,assuming there is a Virtual Cluster Head(VCH) in the center of each cluster area,and selects the nodes one hop distance from the VCH as Candidate Cluster Head(CCH).A Minimum Spanning Tree(MST),which chooses sink as root node and connects each VCH,is generated by the Prim algorithm.Starting from the sink,it chooses Cluster Head(CH) from CCH for clusters in each branch of the MST using dynamic programming.A backbone tree that connects all CH to the sink in the sequence of MST is constructed.Simulation results prove that,when the compressive ratio is 10,compared with clustering without CS,SPT without CS,SPT with hybrid CS,and clustering with hybrid CS,the reduction ratio of traffic of the method respectively are 65%,55%,40% and 10%.
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Computer Engineering. 2018, 44(10): 136-140. https://doi.org/10.19678/j.issn.1000-3428.0048280Aiming at the co-channel interference between transceivers and data streams in Multi-Input Multiple-Output(MIMO) interference channel,a joint nonlinear Tomlinson-Harashima Precoding(THP) transceiver design method is proposed to minimize the total Mean Square Error(MSE),and the local optimal solution is found by alternating iterations to obtain the receiver matrix,the transmit precoding matrix and the feedback matrix.Simulation results show that the proposed method can effectively suppress the co-channel interference in the MIMO interference channel,especially when the transmitter sends a full data stream,it can obtain better error performance than the joint linear transceiver design method.
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Computer Engineering. 2018, 44(10): 141-146,153.. https://doi.org/10.19678/j.issn.1000-3428.0048693A multi-service virtual resource allocation algorithm for satellite network based on improved Stackelberg game model is proposed,in order to solve the problem of low utilization rate of resources,allocation unfairness and low service success rate of satellite network.In this model,it divides the business requests of the satellite network into high priority and low priority categories and established optimization model for different priority service requests to improve the success rate of the service execution.According to the correlation,which includes business and resource,it changes business priority dynamically and efficient business matching of resources to achieve fairness between different business and the rational use of resources.Simulation results show that the service success rate of task is increased by 20% compared with FCFS algorithm and the optimal matching algorithm.The fairness of resources allocation is increased by 50%,and the utilization of resource is increased by 20%.
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Computer Engineering. 2018, 44(10): 147-153. https://doi.org/10.19678/j.issn.1000-3428.0048421Aiming at the low energy efficiency problem of routing and cache management algorithm in Information-Centric Networking(ICN),an energy efficiency routing and cache management strategy based on Fruit Fly Optimization Algorithm(FOA) is proposed.Apply FOA to the ICN’s user request routing process,and according to the characteristics of ICN network,the optimal path is obtained by using network energy consumption as the flavor concentration in FOA.Record the request to merge nodes along the route and determine whether to cache the merged nodes by setting the cache decision function.Simulation results show that compared with the LCE,LCD and Heuristic cache algorithm,the algorithm can reduce the network energy consumption and quickly acquire the network cache,avoid a large number of network content redundancy,and reduce the energy consumption from network equipment management.
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Computer Engineering. 2018, 44(10): 154-159,174. https://doi.org/10.19678/j.issn.1000-3428.0048521In order to solve the problem of node deployment,location and tracking of Wireless Sensor Network(WSN) in indoor applications,it is necessary to study the propagation characteristics of unbelievable signals.Aiming at the typical indoor corridor environment,the path loss characteristics of the 2.4 GHz wireless signal are measured.The relationship between the angle of the transmitting antenna and the horizontal space,the height h of the transmitting antenna and the path loss is analyzed.Then,the linear regression curves are used to analyze the data.Test and fitting results show that the path loss of the wireless signal propagation is the lowest in the environment of the indoor corridor when the angle D is 90°,and the change of the path loss decreases with the increase of the antenna height h,and the path loss at h=1.5 m.
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Computer Engineering. 2018, 44(10): 160-167. https://doi.org/10.19678/j.issn.1000-3428.0048357The existed similarity calculation methods of words are mainly focus on the path structure of words and consider less about the semantic information of words in detail,which lead to inaccurate calculation results.Aiming at this problem,an improved semantic word similarity calculation method is proposed.The CiLin coding and path structure are combined to calculate the similarity between CiLin coding,while using local sensitive Hash algorithm and Hamming distance.Experimental results show that the proposed method can make Pearson correlation coefficients achieve 0.897 4 and 0.866 8 on the MC data set and the RG data set respectively.It is more accurate than the traditional path-based and depth-based calculation methods.
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Computer Engineering. 2018, 44(10): 168-174. https://doi.org/10.19678/j.issn.1000-3428.0047966A general pattern index upper bound estimation method based on modified Binary Particle Swarm Optimization (BPSO) algorithm is proposed to estimate the boundary value estimation problem in constrained frequent pattern mining.According to the characteristics of the uncertain transaction database with weights,a general pattern index upper bound estimation framework is established,and the method of solving the upper bound value of the pattern index based on the modified BPSO is proposed.The number of candidate itemses,runtime and memory usage of the UHUI-Apriori with Transaction Weighted Utilization(TWU),the proposed method estimates upper bound and the actual upper bound are compared,and the results show that the proposed method can quickly calculate the upper bound value of the mode utility and save the running time and memory space.
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Computer Engineering. 2018, 44(10): 175-181,189. https://doi.org/10.19678/j.issn.1000-3428.0048566The uncertain interval number clustering algorithm based on Fuzzy C-Means (FCM) has the problem that the point in the interval number is usually assumed to be the uniform distribution and difficult to express its real attribute,the clustering results are greatly affected by the initial clustering center and the updating speed of membership degree is slow.Therefore,an uncertain Efficient Fuzzy C-Means for Interval-valued Data(EFCM-ID) clustering algorithm based on general distributed interval number is proposed.Based on the idea of quartile,the distance metric MQ distance for general distributed interval numbers is designed,and the uncertain data are accurately described.Combining the density idea and random sampling strategy,an optimal selection method SDCS of initial clustering center is proposed to improve the accuracy of the algorithm,and then a relative accelerated membership updating strategy is constructed by using the competitive learning theory,which reduces the running time of the algorithm.Experimental results show that,compared with YFCM,XFCM and ExpFCMd-ID algorithm,this algorithm has better stability and higher clustering efficiency.
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Computer Engineering. 2018, 44(10): 182-189. https://doi.org/10.19678/j.issn.1000-3428.0050211In order to quantify the uncertainty of the occurrence of hesitant fuzzy event in random experiment,the probability of hesitant fuzzy event is defined combining fuzzy probability theory and hesitant fuzzy set theory.The definition of conditional probability of hesitant fuzzy event is given on this basis.This paper proves several properties of the probability of hesitant fuzzy event,for instance,the countable additivity and continuity.Properties of the conditional probability of hesitant fuzzy event such as multiplication theorem,the law of total probability and Bayes formula are proved.The properties of the probabilities of hesitant fuzzy events in other union and intersection operations are compared,a comparison criterion for the probabilities of hesitant fuzzy events and the steps of the hesitant fuzzy probability reasoning method are given.Example result shows that the probability of hesitant fuzzy events can better deal with the uncertainty of events.
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Computer Engineering. 2018, 44(10): 190-195,203. https://doi.org/10.19678/j.issn.1000-3428.0048793The existing top-down role of the project ignores the requirements of the enterprise for sensitive tasks,resulting in a low set of security.In order to improve the security of role division,a user role assignment method constrained by static separation of duty is proposed.Based on the static mutex exclusive role constraint set,the greedy algorithm is used to generate mutex role pairs and map them to sparse graphs.By using Welch Powell coloring method,adjacent vertices are dyed into different colors,and the number of coloring is approximately equal to the minimum number of users.Roles are divided according to their colors,and roles assigned to the same group can only be assigned to the same user.Experimental results show that this method is efficient,secure and it can save storage space effectively.
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Computer Engineering. 2018, 44(10): 196-203. https://doi.org/10.19678/j.issn.1000-3428.0050934In order to improve the recognition accuracy of pedestrian re-identification algorithm based on pedestrian attribute learning,an improved pedestrian re-identification neural network model is proposed.Based on the heterogeneity between attributes,different recognition methods are designed in the neural network to identify various kinds of attributes to improve the accuracy of pedestrian attribute recognition.Aiming at the inconsistency of the loss measurement algorithm of different attribute recognition methods,the heterogeneous attribute loss measurement function is given,so that different recognition methods can be trained and learned in the same network model to optimize the network parameters.Experimental results show that the first accuracy rate of the model on the Market1501 dataset,DukeMTMC dataset and DukeMTMC dataset respectively reaches 88.13%,74.96% and 77.64%.
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Computer Engineering. 2018, 44(10): 204-208. https://doi.org/10.19678/j.issn.1000-3428.0048752Aiming at the problem of neglecting project similarity information in classical social network recommendation algorithm,an improved personalized recommendation algorithm for social network is proposed. The global project similarity information between projects is mined,and the reliability of trust values among social network users is analyzed,and the two are combined in a model to realize personalized recommendation to users. Experimental results on Filmtrust datasets and Ciao datasets show that,compared with PMF,SocialMF and SoRec algorithms,this algorithm can improve the accuracy of recommendation and reduce the recommendation error in cold start problem.
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Computer Engineering. 2018, 44(10): 209-214. https://doi.org/10.19678/j.issn.1000-3428.0048159The existing concept graph matching methods have the problem of poor matching fault tolerance.Therefore,this paper proposes a new method to explore the relationship between patent and effect.Long Short-term Memory(LSTM) is used to combine with bidirectional LSTM which based on the attention mechanism to train the patent corpus.The Softmax classification model is used to classify the patent and the effect of the patent is obtained.Experimental results show that the method uses the Bi-LSTM-ATT model to train has certain validity in determining the effect of patents,and the accuracy can reach more than 70%.
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Computer Engineering. 2018, 44(10): 215-220. https://doi.org/10.19678/j.issn.1000-3428.0048388Aiming at the shortcomings of insufficient capacity in the current encrypted domain reversible information hiding technique,a completely separable large capacity reversible information hiding algorithm is proposed.Arnold transform is used to encrypt original image,and pixel values of the encrypted image are divided into different intervals according to Most Significant Bit(MSB),so each pixel belongs to a specific interval.Secret messages are embedded into the encrypted image by matrix-encoding.At the receive end,the secret messages are extracted accurately with the help of the location map and the steganalysis key.The encrypted image can be restored by simple calculation,and then the original image can be obtained by decrypting the encrypted image without error.The correctness of the scheme is demonstrated by derivation.Experimental results show that the method can extract the secret information accurately and restore the carrier image without loss,and realize the complete separation of these two operations.
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Computer Engineering. 2018, 44(10): 221-227. https://doi.org/10.19678/j.issn.1000-3428.0048606The image obtained by the traditional dark channel prior image defogging fog method is dark and the quality is not high.To solve this problem,a telegraph equation model containing bidirectional diffusion and adaptive shock filtering is established.The edge detector is combined with impulse filtering and the weight coefficient is adaptively selected from the gradient feature of the image to form the sharpening term,so that the image can be enhanced adaptively according to the characteristics of different regions.Adding fidelity items to ensure that the enhanced image preserves the main features of the original image and prevents distortion of the image.On this basis,the finite difference method is used to solve the model numerically to obtain the enhanced image.Experimental results on foggy images show that,compared with the defogging algorithm based on dark channel prior theory and the enhancement algorithm based on adaptive impulse filtering,the proposed algorithm has obvious visual enhancement effect,which can improve the image brightness,reduce the noise effect and improve the image quality.
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Computer Engineering. 2018, 44(10): 228-234. https://doi.org/10.19678/j.issn.1000-3428.0048512In order to obtain the robustness Inverse Synthetic Aperture Radar(ISAR) image,an iterative minimization Bayesian learning sparse signal recovery algorithm is proposed.Firstly,ISAR imaging is established,and the imaging problem is converted to sparse constraint Maximum A Posteriori (MAP) estimation under Bayesian criterion.Then,the target reconstruction and the noise power can be obtained simultaneously by exchanging iterative solution,and the target can be recovered.Compared with the conventional sparse recovery algorithms,the proposed algorithm can adjust parameters automatically.Real data experimental results show that the paramters of the proposed algorithm can be adjusted autonomically and have better imaging effect comapred with SL0 algorithm,OMP algorithm and BP algorithm.
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Computer Engineering. 2018, 44(10): 235-240. https://doi.org/10.19678/j.issn.1000-3428.0048254Automatic tracking and segmentation of coronary arteries in Computed Tomographic Angiography(CTA) sequence images have clinical significance and especially can help cardiologists make intuitive and rapid diagnosis.According to the characteristics of CTA images,this paper proposes a tracking algorithm based on feature matching and improved particle filtering to track the target of coronary artery.It realizes the automatic tracking of coronary object,and finally generates a high-precision 3D model of coronary artery.The proposed improved particle filtering algorithm changes particle resampling rules and provides the basis for tracking the suddenly changed motion targets.Experimental results show that the proposed algorithm can solve many difficult problems such as bifurcation,morphological change and severe change of motion state in coronary tracking.It has higher accuracy and better robustness,which can be used for the clinical diagnosis of coronary heart disease.
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Computer Engineering. 2018, 44(10): 241-245,251. https://doi.org/10.19678/j.issn.1000-3428.0048785ViBe algorithm is easy to produce ghost and void phenomena in moving vehicle detection.To solve this problem,a background subtraction algorithm based on dual-feature modeling and adaptive threshold is proposed.Firstly,the background model of the first video sequence is constructed by Scale Invariant Local Ternary Pattern(SILTP) feature and color feature,and then the discriminant method of ViBe algorithm is improved by combining the changes of the two features.When a pixel is identified as a foreground,Otsu algorithm is used to calculate the optimal segmentation threshold of the image and the foreground pixels are judged for the second time according to the threshold.Finally,the improved ViBe update strategy is used to update the background model.Experimental results show that,compared with ViBe algorithm,the proposed algorithm can suppress ghost and void phenomena,improve the accuracy of moving vehicle detection,and has better robustness when illumination changes.
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Computer Engineering. 2018, 44(10): 246-251. https://doi.org/10.19678/j.issn.1000-3428.0048545The traditional three-frame difference target detection algorithm is prone to the phenomenon of edge missing,which makes it impossible to completely fill the hole in the target by morphological processing.To solve this problem,an edge contrast difference target detection algorithm is proposed to obtain the target edge.A theoretical model is established based on the continuity of video images and the uncertainty of velocity of moving targets.The traditional edge difference algorithm and the edge contrast difference algorithm with fixed parameters are analyzed.A method of adaptive acquisition of current model parameters based on target motion parameters is proposed,which can reduce the error rate of background points and obtain a complete target edge.Experimental results show that,compared with the traditional three-frame difference algorithm,this algorithm can extract moving objects from video sequences quickly and effectively,and has better robustness.
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Computer Engineering. 2018, 44(10): 252-257. https://doi.org/10.19678/j.issn.1000-3428.0048542In order to overcome the shortcoming that the traditional learning algorithm training has limited dictionary size and large amount of computation,the algorithm of underdetermined blind source separation for speech signal based on the dictionary learning is studied.Firstly,a redundant dictionary is trained by adopting double sparse dictionary training algorithm to carry out the sparse decomposition of the observed signal.Then it analyzes the equivalence property of underdetermined blind source separation and Compressed Sensing(CS) equivalence problems,builds a model of underdetermined blind source separation based on CS,and also applies the Orthogonal Matching Pursuit(OMP) algorithm to reconstruct the signal to achieve speech signal underdetermined blind source separation.In the premise of guaranteeing the separation accuracy,the algorithm reduces the computational complexity of dictionary construction,improves the validity of signal sparse representation and reduces the running time of reconstruction algorithm.Experimental results show that the algorithm is better than the KSVD algorithm and online dictionary learning algorithm,which greatly improves the computational efficiency.
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Computer Engineering. 2018, 44(10): 258-263. https://doi.org/10.19678/j.issn.1000-3428.0048149In order to reduce the computational complexity of High Efficiency Video Coding(HEVC) inter-frame prediction,a fast Coding Unit(CU) depth selection algorithm is proposed in this paper.Firstly,the spatio-temporal correlation of depth information among the current CU and adjacent CU is used to preliminary forecast the depth of the current CU.Secondly,the CU depth of current CU is judged further for stop based on the Motion Vector(MV)information of current CU and adjacent CU.The experimental results demonstrate that,compared with the HEVC test model(HM16.0),under two coding structures of low-delay and random-access,the proposed algorithm increases bit rate by 0.93% and 1.01% and saves coding time by 29.1% and 30.3%,respectively with the same objective quality.
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Computer Engineering. 2018, 44(10): 264-273,280. https://doi.org/10.19678/j.issn.1000-3428.0050904
At present,depression is treated with antidepressant drugs and assisted with psychotherapy and physical therapy,and these expensive and time-consuming treatment methods often end prematurely and result in a prolonged course without effective symptom relief.Therefore,based on the neurofeedback therapy,a novel depression rehabilitation method using a Virtual-Reality(VR) game framework is proposed.In this VR game framework,an innovative three-electrode Electroencephalography (EEG) collector is used to record patients’ EEG data.The data are processed and converted into feedback features,and the feedback will be displayed to patients in real time through a VR headset.Patients can adjust their psychological activity based on the feedback,and relieve their physiological dysfunction effectively.The framework also provides a data storage module,which may offer therapists ways to assess patients’ rehabilitation results in a long term,as well as provide possibility to continue towards better algorithm of feedback features with data-mining.The prototype system is tested in the framework,and the experimental results prove the effectiveness of the framework in depression rehabilitation.
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Computer Engineering. 2018, 44(10): 274-280. https://doi.org/10.19678/j.issn.1000-3428.0048956Affected by cell users,the resource allocation policies for multicast in Long Term Evolution(LTE) system are usually inefficient,which causes the low quality of multicast service.Aiming at this problem,this paper proposes an online resource allocation algorithm for multicast to adopt change and diversity of user channel by combining Scalable Video Coding(SVC) with Adaptive Modulation and Coding(AMC).It formulates the problem as maximizing the time average video quality subject to the time average resource blocks constraint,then solves the problem via the theory of Lyapunov stochastic optimization.The simulation results show that,compared with MSML algorithm,the proposed algorithm can improve video quality effectively at the same bandwidth consumption.
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Computer Engineering. 2018, 44(10): 281-285,291. https://doi.org/10.19678/j.issn.1000-3428.0048134
In speech cognition,a substantial amount of data is required for acoustic model training,so the performance of the Deep Neural Network(DNN) acoustic model trained on a scarce amount of data is limited.Aiming at this problem,this paper proposes a transfer learning method to improve the Uyghur speech recognition starting from models trained by other resource-rich speech databases,so as to get a better acoustic model for Uyghur speech recognition.Experimental result shows that the above method can significantly improve the Uyghur speech recognition performance compared with the baseline models trained only on Uyghur speech database.
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Computer Engineering. 2018, 44(10): 286-291. https://doi.org/10.19678/j.issn.1000-3428.0049193
AVS-P10 is a national standard for low bit rate bandwidth extension schemes,but since the standard only uses the high frequency envelope information and the high frequency gain to adjust the high frequency portion of the restored signal,the restored sound quality is poorer.Aiming at this problem,after analyzing the corresponding bandwidth extension principle of AVS-P10,a novel bandwidth extension scheme based on tonality adjustment is proposed.Tonality parameters are extracted from the encoder part in Fast Fourier Transform(FFT) domain,which are recovered to adjust the steep peaks and dips in decoder.Experimental results show that, compared with AVS-P10 standard,the proposed scheme can improve the ODG score by 9.4% with the objective judgement test,and the CMOS score by 1.14 with the subjective test part,which concludes that the reconstructed audio quality is improved.
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Computer Engineering. 2018, 44(10): 292-297,302. https://doi.org/10.19678/j.issn.1000-3428.0050770
Most of the existing text abstract methods stay in the shallow semantic relationship between words and words,and do not make good use of the complete semantic information between words.Therefore,an improved algorithm for semantic subgraph predictive summary is proposed.The algorithm transforms the original text into corresponding Abstract Meaning Representation(AMR) graphs,merges them into an AMR total graph,and filters the redundant information based on the WordNet semantic dictionary.On this basis,using the comprehensive statistical features assigns weights to the AMR graph nodes that do not have weights,and constructs the semantic summary subgraphs by filtering the parts with high importance,and comprehensively measures the quality of the abstracts based on the ROUGE index and the Smatch index.Experimental results show that compared with the text abstraction benchmark algorithm which only mines shallow semantic relations,the ROUGE value and Smatch value of the algorithm are significantly improved.
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Computer Engineering. 2018, 44(10): 298-302. https://doi.org/10.19678/j.issn.1000-3428.0049408
Due to linear fitting,the measurement error of laser triangulation ranging technique is large,and the linearity decreases in the case of large range ranging.To solve this problem,a high precision laser displacement sensor measurement method based on residual compensation is proposed.The distance measurement method based on laser displacement sensor is analyzed.The residual compensation and fitting method are optimized by traditional laser triangulation technology to reduce the theoretical error caused by direct fitting.Experimental results show that compared with the laser triangulation method,this method can solve the problem that the measurement error becomes larger due to direct linear fitting and realize high precision large displacement measurement.
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Computer Engineering. 2018, 44(10): 303-308,313. https://doi.org/10.19678/j.issn.1000-3428.0049509
In the economic society,the rumor involving individual interests is increasing gradually.Aimed at the existing bandwagon effect in the process of actual rumor spreading and combined with the node bandwagon effect as well,a new game revenue is defined while a rumors propagation model is established by leveraging the game theory.Considering the correlation between the spread of rumors and the interests of node,the selective safety coefficients are introduced to describe the non-uniform spread rates in different nodes,and decision-making conversion factors are utilized to describe the probability of the changes in the course of spreading rumors.By using a typical BA (Barabási-Albert) scale-free network and real network data in the Twitter,the experimental results show that,on the one hand,with the increase of autonomous selection factor,the spread of rumors in the network becomes smaller;on the other hand,with the increase of time conversion factor,the ratio of healthy nodes to infected nodes first increases,then decreases and finally converges to zero.
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Computer Engineering. 2018, 44(10): 309-313. https://doi.org/10.19678/j.issn.1000-3428.0049981Aiming at the situation that the accuracy of image steganalysis is not high,a steganalysis model of Convolutional Neural Network(CNN) based on Multi-layer percepual convolution layer(Mlpconv) is constructed.The model uses multi-layer perceptual convolution layer instead of the traditional linear convolution layer to improve the nonlinear capability of the model and extract more abstract features of the carrier/steganographic image;the global average pooling layer is used to instead of the fully connection layer,which effectively reduces the network parameters and improves the training efficiency of the model.Experimental results show that compared with the traditional image steganalysis algorithm and the existing steganalysis model of convolutional neural network,the model can effectively improve the detection effect of steganalysis,and the accuracy of steganalysis detection of S-UNIWARD embedding algorithm reaches 90.87%.
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Computer Engineering. 2018, 44(10): 314-320. https://doi.org/10.19678/j.issn.1000-3428.0048103For the problem that the Electric Multiple Unit(EMU) electro-pneumatic braking force distribution control strategy has less considered there are differences in the adhesion limit of each vehicle,this paper proposes an optimization control algorithm of air braking force distribution with the total maximum utilization ratio of adhesion as the objective function.On analysis of electric brake priority for the basic control in the CRH2 EMU,it lists the objective function and constraint condition of the optimal allocation of air braking force and resolves it by the quadratic programming.The Matlab/Simulink software is used to simulate the distribution of air brake force under the fast braking condition of EMU.Compared with the traditional method of load distribution,the results show that this algorithm can make full use of different adhesion limit of each trailer car and reduce the braking force of the motor vehicle and the slipping phenomenon of the moving car in the braking process,which can improve the train braking performance.
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