15 March 2015, Volume 41 Issue 3
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Computer Engineering. 2015, 41(3): 1-6. https://doi.org/10.3969/j.issn.1000-3428.2015.03.001
To solve the problems just like limited cut point and handoff frequently when switching in low earth orbit,an algorithm that is used to orientate the handoff point based on the theorem called flat fan angle and the security cutting protocol related which is based on optimization strategy is proposed. Firstly,the flat sectorial angle theorem is applied to fix the latitude and longitude coordinates of the switch point,using this method avoided the limitations of the application of spherical triangle theorem;Therefore the new algorithm can calculate any cutting point in space. Secondly,it optimizes the performance of switching protocol from two aspects:Choosing the satellite which is most fit for the aircraft in speed to be next-hop satellite when switching,doing like that can shrunk the cut frequency;The new protocol is enhanced security by drawing into historical record which can reflect the past secret key and the integrity of orders. Finally,the new protocol is designed under the context transmission mode,which can decrease the communication and computing costs when compared with protocols under other authentication mode. Simulation experimental results show that the low communication and computing costs,less switching frequency and high security features makes the protocol be more suitable for LEO satellite network.
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Computer Engineering. 2015, 41(3): 7-14. https://doi.org/10.3969/j.issn.1000-3428.2015.03.002
Microblog is not only a center or channel of mass media,but also involved in the formation,development and guidance of public opinions. The propagation of speculation microblog which is released from We-media,opinion leaders or some other users,causes microblog rumors,false hype,social mobilization and other problems. This paper analyzes the phenomenon of covert planning,mines the difference of the structure in communication networks and the incremental statistics of forwardings between the ordinary and the speculation. A novel algorithm for hype microblog recognition is proposed in this paper based on Support Vector Machine (SVM) which uses the modularity peak spread and the average diameter of the shortest path in propagation network. The proposed method has advantages of less dependence on user profile information and is sensitive to the structure of propagation networks,and it has higher recognition accuracy.
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Computer Engineering. 2015, 41(3): 15-20. https://doi.org/10.3969/j.issn.1000-3428.2015.03.003
Wireless Local Area Network (WLAN) can be combined together with 3G network to be the carrier of Internet of Things (IoT). To solve the problem of security and group communication in recent access authentication schemes,this paper proposes a Secure and Efficient Group Access Authentication Protocol (SEGAP). It sets up the equipment group in initialization and registration stage and accomplishes the secure access in authentication and key agreement stage. Compared with conventional EAP-AKA,this scheme guarantees stronger forward security by adopting Elliptic Curve Diffie-Hellman (ECDH),enables first equipment in group to acquire group authentication vector,this paper shares it with others who come later,and provides better authentication performance by realizing group access authentication. The analysis results illustrate that the protocol can reduce the cost of group communication and can be applied to the business of IoT very well.
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Computer Engineering. 2015, 41(3): 21-25. https://doi.org/10.3969/j.issn.1000-3428.2015.03.004
Taking advantage of vector merging algorithm and homomorphic Hash function,this paper proposes a data integrity scheme for multi-source network coding against pollution attacks. Each source node computes raw massage’s Hash values and uses a secure mechanism to sign the Hash values,then appends the Hash values and its signatures to each message which sends to forward nodes and sink nodes. The forwarder can verify the integrity of network coded data from different source nodes without knowing the sources private keys and generating the Hash for the combined messages. Experimental results show that the computation efficiency of the proposed scheme is better than the existing multi-source network coding scheme,and it is more suitable for the large-scale distributed network data security verification.
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Computer Engineering. 2015, 41(3): 26-31,36. https://doi.org/10.3969/j.issn.1000-3428.2015.03.005
Web services composition is a key technology to solve cross-organizational business process integrations. However,it is hard to ensure its trusted properties (including correctness,reliability,safety),because of the loosely coupled development paradigm and open Internet running environment. To solve this problem,this paper proposes a formal verification and abstraction method for Web services composition based on model checking Multi-Agent Systems (MAS) and refinement. By applying the method of the graph-like counterexample guided abstraction and refinement on MCTK,it greatly reduces the state explosion problem of model checking. The correctness of the method is proved theoretically. Recording to the experimental results of which translates a credit risk assessment Web services to a MAS programmed by input language of MCTK then model checks both abstracted and un-abstracted MAS,the Web services verification based on proposed method works much more efficiently than the normal verification based on MAS model checking.
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Computer Engineering. 2015, 41(3): 32-36. https://doi.org/10.3969/j.issn.1000-3428.2015.03.006
The traditional DV-Hop localization algorithm estimates the average hop distance with the physical distance between the anchor nodes instead of actual transmission distance,and the distance error between the two kinds of distance undoubtedly leads to the inaccuracy of the average hop distance and relatively high localization error. Aiming at this problem,the improved algorithm is proposed. The reason of error between the physical distance and actual transmission distance is analyzed in the paper,and is summarized as the asymmetry of distance resulted from the nodes random distribution,as well as the deviation degree between the actual transmission path and the physical distance,and the distance compensation model is built based on the asymmetry and deviation degree to make the physical distance closer to the transmission distance. The improved algorithm increases no extra hardware and the complexity of the DV-Hop. The simulation results show that the improved algorithm compensates the distance between the anchor nodes,and improves the localization accuracy to the unknown nodes.
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Computer Engineering. 2015, 41(3): 37-40,46. https://doi.org/10.3969/j.issn.1000-3428.2015.03.007A new hop-to-hop congestion mathematical model between the network-layer and the link-layer is presented based on the tank balance relationship of the inflows and outflows for the node-congestion control in Wireless Sensor Network(WSN). The congestion control model is simpler than ever before and is easy to implement and a discretesliding mode controller is designed based on the reaching-law. The simulation results show that the proposed model is better than the traditional PID and fuzzy control in terms of response and delay.
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Computer Engineering. 2015, 41(3): 41-46. https://doi.org/10.3969/j.issn.1000-3428.2015.03.008Content-centric Network(CCN) based on named data which is one of the vital elements in network,as a main architecture for the future Internet,attracts considerable attention from the research community recent years. A new caching scheme called PopBetw based on content popularity and node’s betweenness is proposed to solve the problem of heavy replacement of content copies brought by existing cache policies in CCN:combining content popularity which is one of content attributes with node’s betweenness avoids caching unpopular contents,reduces caching load in each node and improves in-network caching performance. Simulation experiment demonstrates that the proposed PopBetw caching strategy achieves larger cache hit rate and lower path stretch than that of LCE scheme,LCPro and EgoBetw scheme by evaluating the impact of cache size and content popularity on the caching performance,it also shows that PopBetw apparently lower the number of in-network cache replacement especially in nodes with relatively large value of betweenness to achieve better overall performance.
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Computer Engineering. 2015, 41(3): 47-52. https://doi.org/10.3969/j.issn.1000-3428.2015.03.009Microgrid needs the Energy Management System (EMS) to optimize and control Distributed Generation (DG),but the traditional software development models and middleware technologies are insufficient in module hot-plug capability and code invasion. Based on the 100 kW photovoltaic microgrid project in Anhui Polytechnic University,this paper proposes a microgrid EMS based on Distributed Open Service Gateway initiative(D-OSGi),and then discusses the aspect-oriented approach to extend the D-OSGi,software logical layers of EMS,energy scheduling strategies and changes of SCADA graphics primitive. The implementation approach of EMS in Xuancheng microgrid is presented,and some tests are done for typical modules’ functionality. The results show that the system reduces the difficulties to customize and extend functions effectively,and it is convenient for power system related researchers to simulate microgrid control algorithms rapidly.
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Computer Engineering. 2015, 41(3): 53-58. https://doi.org/10.3969/j.issn.1000-3428.2015.03.010This paper studies the task scheduler in a widely used embedded μC / OS-Ⅲ kernel. After selecting core parts from the scheduler,it specifies the properties of the scheduler formally. Based on the separation logic and SCAP,it builds a verification framework including a machine model,operational semantics,assertion languages,and inference rules. In the framework,assertions specifying system data structures and properties are defined,and system code is able to be reasoned about modularly. Finally,the properties of the task scheduler in μC / OS-Ⅲ are formally proved,and the entire proof provided by the work are machine checkable.
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Computer Engineering. 2015, 41(3): 59-63. https://doi.org/10.3969/j.issn.1000-3428.2015.03.011In order to solve the problem of the performance degradation caused by the resource competition among the applications in smart TV, this paper presents a resource usage prediction based resource cache algorithm. The applications’ resource consumption data is recorded and the resource state and resource bottleneck of the next time interval are predicted by Markov model. The weight of each application is adjusted dynamically and the resource cache problem is converted to multidimensional multiple-choice knapsack problem to minimize the switch time of the application. A lightweight heuristic solution algorithm with lower time complicity is presented. Simulation results show that the precision of the resource usage prediction of the algorithm is superior to others by about 5. 4% ,and the switch time of the application is reduced by about 45% .
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Computer Engineering. 2015, 41(3): 64-70. https://doi.org/10.3969/j.issn.1000-3428.2015.03.012.In order to simplify the design complexity of using NAND flash storage to save mass data in embedded systems,a method of constructing solid state memory using Ferroelectric Random Access Memory(FRAM) to achieve fast and efficient access is presented. The optimal protocol of the combination of serial FRAM and RAM is developed. The concept of memory block query and fast query algorithm of serial FRAM data storage are proposed. The storage protocol of the combination of serial FRAM and RAM and the algorithm of block read / write are introduced. The design of motor drive system load tester based on 51 single chip microcomputer and industrial tests show that the solid state memory designed by ferroelectric memory has smaller software and hardware overhead,faster access speed,the realization of simple and reliable. It meets the long-term storage requirements of embedded systems.
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Computer Engineering. 2015, 41(3): 71-76. https://doi.org/10.3969/j.issn.1000-3428.2015.03.013Aiming at the domain of video service network in tri-network convergence,this paper focuses on the problem of optimal resource allocation of Real-time Service Provide Equipment(RSPE) nodes in shared resource pools. This paper proposes a fully distributed optimal control solution,named RSPE-DOC. RSPE-DOC treats underlying physical servers as a shared resource pool,and RSPE nodes as resource consumers. RSPE-DOC implements the information exchanging strategy and distributed optimization method among RSPE nodes,leading to a distributed optimal control framework.Experimental results indicate that RSPE-DOC is able to ensure the convergence of dissemination process and find the optimal resource allocation,when the RSPE nodes are not changed substantially in resource management process.
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Computer Engineering. 2015, 41(3): 77-80,87. https://doi.org/10.3969/j.issn.1000-3428.2015.03.014To achieve interconnection between different Near Field Communication(NFC) devices,Peer to Peer(P2P) communication of NFC device as the object of study,this paper designs and implements P2P communication between NFC mobile terminal and NFC reader based on Android platform. NFC mobile terminal and NFC reader takes NFC Data Exchange Format(NDEF) as the communication unit,based on the Simple NDEF Exchange Protocol(SNEP) protocol,a party is as a client to send the message transmission request,and the other is as a server to respond client request. It is to enable NFC mobile terminal interact with NFC reader through command-response message pair in Application Protocol Data Unit (APDU). Test results show that both NFC mobile terminal and NFC reader can take the initiative send messages to each other,and better achieve P2P communication between NFC mobile terminal and NFC reader.
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Computer Engineering. 2015, 41(3): 81-87. https://doi.org/10.3969/j.issn.1000-3428.2015.03.015Traditional erasure coding scheme is universally adopted to enhance the fault tolerance,which produces too much data transmission in a repair process. A new construction scheme of quasi-cyclic Minimum Storage Regenerating (MSR) regenerating codes is proposed in this paper. According to its property of exact repair about the weight of encoding vector and the bound of repair bandwidth,it proposes an improved node repairing algorithm which optimizes the repair bandwidth to the cut-set bound,and it is also better than Maximum Distance Separable(MDS)codes in the worst case. Experimental result shows that the construction scheme not only can save the storage space but also has simple structure,low operation cost and low repair bandwidth,etc.
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Computer Engineering. 2015, 41(3): 88-91,96. https://doi.org/10.3969/j.issn.1000-3428.2015.03.016This paper proposes an improved congestion control strategy to alleviate the congestion of random access channel in radio access network of Machine Type Communication(MTC) based on 3GPP-Long Term Evolution(LTE). In order to reach the base-station’s load balancing in the time interval and allocate the channel resources rationally,it schedules the access time of MTC devices through the base-station’s broadcasted information,and thereby avoids access collisions caused by massive number of MTC devices access the base-station simultaneously. It also proofs that uniform distribution of the access time is the optimal choice by maximum entropy principle. Simulation experimental results show that the strategy can alleviate the channel congestion significantly and increase the random access success rate of MTC devices,reduce the delay,and thus improve the network’s performance and guarantee the network’s Quality of Service (QoS) compared with Access Class Barring(ACB) strategy.
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Computer Engineering. 2015, 41(3): 92-96. https://doi.org/10.3969/j.issn.1000-3428.2015.03.017Aiming at the disadvantage of existing routing algorithm in distributed parallel processing system,a novel and effective routing policy is proposed. The concrete implement is to obtain the packet fore-and-aft arriving time distribution Pt (x) and the packet size distribution Pp (x) from input packets,and a weight function is introduced to achieve the minimal average delay of all packets by learning continuously average fore-and-aft arriving time,average packet size and vector. Simulation result shows that the minimal average delay of all packets can be obtained not only in the condition of the varied number of processors,but also in the condition of the changed packet fore-and-aft arriving time and the packet size distribution.
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Computer Engineering. 2015, 41(3): 97-101,105. https://doi.org/10.3969/j.issn.1000-3428.2015.03.018This paper designs a kind of encoding and decoding algorithm with a low complexity based on the data correction method to resolve the data stream errors which Single Event Upset(SEU) may bring. It uses the theory of linear block codes to analyze various methods of data fault tolerance,and designs a kind of encoding and decoding algorithms with a low complexity of linear block code from the encoding and decoding principle of linear block codes,the fault-tolerant coding method can effectively correct single-bit data errors caused by SEU, with low fault-tolerant overhead. Fault injection experiments show that this method can effectively correct data errors caused by single event upset,compared with other common error detection or correction methods,error correction performance of this method is superior,while its fault tolerance cost is less.
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Computer Engineering. 2015, 41(3): 102-105. https://doi.org/10.3969/j.issn.1000-3428.2015.03.019A novel data transmission mechanism based on flooding for low-duty-cycle Wireless Sensor Network (WSN),named Multi-flooding(MF) is proposed. Using MF,the node which has data to send will keep trying to flood the data to its destination for K times,while K depends on the required successful transmission ration. Simulation results show that MF with limited times does not generate much more broadcasting packets and energy consumption compared with other routing protocols, but reduces the transmission delay and increases the successful transmission ration remarkably.
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Computer Engineering. 2015, 41(3): 106-109. https://doi.org/10.3969/j.issn.1000-3428.2015.03.020With the widely application of the Wireless Sensor Network(WSN),the security problem is more and more prominent. The distribution and management of WSN receive more and more attention. This paper proposes a key predistribution scheme which matches patterns according to the fingerprint identification by dividing the network after collecting the deployment information. The scheme divides the network into several domains,and the seed pool is divided into multiple sub-seed pools relatively. Nodes select seeds from relative areas to generate patterns and texts,and use fingerprint function values as communication keys when match successfully. The performance and security analysis shows that the scheme can substantially improve a network’s connectivity and reduce storage consumption compared with the traditional random key pre-distribution scheme.
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Computer Engineering. 2015, 41(3): 110-115. https://doi.org/10.3969/j.issn.1000-3428.2015.03.021To improve the security and privacy problems in Radio Frequency Identification(RFID) tags,a low power UHF RFID security tag baseband in accordance with the independent national protocol(GJB 7377. 1 -2011) is designed. Through studying RFID tags ’ security strategy and comparing plenty of cryptographic algorithms, PRESENT cryptographic algorithm and security protocol are used to ensure tag’ s security. Reuse of several blocks,time-sharing reuses of registers,power management and multiple time regions design are employed to minimize the power consumption of baseband. Experimental results show that the baseband is in accordance with the independent national UHF RFID standard and has security function. The area of the digital baseband is 369. 84 μm × 362. 56 μm,of which the security module takes 36. 5% ,and the power consumption of the baseband is 5. 26 μW.
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Computer Engineering. 2015, 41(3): 116-119,124. https://doi.org/10.3969/j.issn.1000-3428.2015.03.022In a proxy re-signature scheme,a semi-trusted proxy is allowed to transform a signature from a delegatee into a signature from a delegator on the same message using the re-signature key. But the proxy cannot generate signatures for either the delegatee or the delegator. Proxy re-signature schemes in the standard model are existentially unforgeable,which cannot prevent forgeries from forging valid signatures on new messages not previously re-signed. Based on target collision-resistant hash function, a bidirectional proxy re-signature scheme is proposed. Under computational Diffie-Hellman assumption,the proposed proxy re-signature scheme is provably secure against strong forgery under adaptive chosen message attacks. Moreover,the new scheme has some advantages over the available schemes,such as short system parameters,short re-signature and low re-signature computation cost.
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Computer Engineering. 2015, 41(3): 120-124. https://doi.org/10.3969/j.issn.1000-3428.2015.03.023Smart card based authentication scheme for multi-server environments can not resist some known types of attacks,such as forgery attacks,reply attacks and the man-in-the-middle attacks. In order to resolve the aforementioned security problems,this paper proposes a novel multi-server scheme. In new scheme,a self-verified timestamp technique is used to solve the problem of implementing clock synchronization in most typical timestamp-based scheme. In addition, timestamp can be used as random and it is efficient to avoid the reply attacks. Security analysis shows that,compared with smart card based multi-server remote authentication scheme,this scheme not only inherits the merits,such as lightweight computation and low memory size,but also can provide some features,such as the users’ traceability,and it extremely suits for the requirements of the complicated network environment.
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Computer Engineering. 2015, 41(3): 125-129. https://doi.org/10.3969/j.issn.1000-3428.2015.03.024Drawing lessons from the basic principles of social trust network,this paper proposes an access control mode of P2P based on trust of fuzzy evaluation. The trust relationship between nodes is divided into three aspects,direct trust, knowledge of trust,and recommendation trust. It adopts fuzzy theory to evaluate the trust of nodes in P2P network,and realizes access control by extending the Multi-level Security(MLS) mechanism. Before the transaction can be generated between the nodes,according to the trust level of the object node,the subject node grants it different access privileges,so that,the goal of P2P network security is achieved. Some security mechanisms,such as encryption and digital signature,are introduced into this model,as a result,this model is capable of effectively restraining several typical security attacks such as impostor,eavesdrop,and sybil attack. When the proportion of malicious nodes in P2P network is changing,the contrast experiment is doing with the network containing the access control model and without this model. Results show that the success interaction rate of nodes is greatly improved.
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Computer Engineering. 2015, 41(3): 130-135. https://doi.org/10.3969/j.issn.1000-3428.2015.03.025To improve the P2P trust model’ s ability of inhibiting malicious nodes. Grouping nodes in the network according to the level by using the basic fuzzy inference rule and combining trust value and contribution value,and limiting the resource access through the level of the node. Time attenuation function reflecting the actual situation is introduced and penalty factor punishing malicious behavior of the node in the calculation of the comprehensive trust is designed. In the calculation of recommend trust,it effectively reduces the complexity of the algorithm by using the recommend node’s credibility which is calculated by the level of node. According to the analysis of data,the proposed model can effectively inhibit the malicious nodes attack,with the increasing proportion of collusion nodes,free-rider nodes and concussion nodes in the network,file download successful rate of this model is higher than PeerTrust model and EigenTrust model.
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Computer Engineering. 2015, 41(3): 136-141. https://doi.org/10.3969/j.issn.1000-3428.2015.03.026Based on the study of machine learning algorithm,this paper proposes a hybrid intrusion detection scheme using the Extreme Learning Machine(ELM)for Wireless Sensor Network(WSN). It divides the WSN into the perception layer,data aggregation layer and the core control layer,corresponding intrusion detection scheme is presented at each layer.Especially,in the core control layer,it sets trust management modules and ELM modules. Using a trust module can timely sieve to abnormal nodes. The ELM is faster than the SVM algorithm,and the efficiency of intrusion detection can be further improved when using ELM. Experimental results show that the scheme that combines the ELM with traditional intrusion detection technology balances the advantages and disadvantages,reduces the energy consumption and prolongs the network uptime,on the basis of guaranteeing a higher detection rate. So it is more suitable for WSN which is resource-constrained.
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Computer Engineering. 2015, 41(3): 142-146,161. https://doi.org/10.3969/j.issn.1000-3428.2015.03.027This paper introduces the current situation and development of Distributed Denial of Service(DDoS) attack, and proposes a flow potential energy analysis model based on time sequence,constructs sequence of network flow potential energy. It uses Auto Regression(AR) model to fit multi-dimensional parameter vector and describes the stability of network flow in unit time,and employs Support Vector Machine(SVM) based method to classify and train the target network flow character parameter vector,gains the best-matched network data flow potential energy set and final achieves accurate description of different DDoS attacks. It uses DARPA dataset,IXIA 400 network test machine and other softwarehardware fundamentals to construct a real and analysis of the value network,validates the network flow potential energy analysis model based on the constructed network. Analysis and contrasts of the key indicators include DDoS detection accuracy, recognition rate, etc. Experimental results show that the method has higher detection precision and comprehensive better detection quality to DDoS.
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Computer Engineering. 2015, 41(3): 147-150,166. https://doi.org/10.3969/j.issn.1000-3428.2015.03.028
Aiming at the problem of the tag’s ownership safe transfer during its lifetime,an ownership transfer protocol for Radio Frequency Identification(RFID) is proposed,which is based on the Hash function without the Third Trust Party (TTP). It adopts the challenge-response mechanism,and uses the Status flag to indicate the tag ’ s owner. In this protocol,the previous owner and the new owner share different secret keys with the target tag respectively, with communication information transferred between them,and the entities in systems can be authenticated. After a serious of authentication,the new owner obtains the ownership of the target tag. Analysis result shows that the protocol can satisfy the proposed security requirements for tag ownership transfer. The target tag is owned by the previous owner,and only owned by the new owner after the protocol’ s execution. So it can make the tag’ s ownership transfer exclusively. Compared with the previous works,the protocol’s performances on security and implementations are improved.
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Computer Engineering. 2015, 41(3): 151-155,171. https://doi.org/10.3969/j.issn.1000-3428.2015.03.029On common platform, the extraction of run-time control-flow to target binary code relies on either processor’s mechanism or Dynamic Binary Instrumentation(DBI) tools. So,the implementation on common platform can not be transplanted to Advanced RISC Machine(ARM) directly. Based on Control Flow Integrity(CFI) enforcement,this paper designs a method to detect and diagnose control flow hijacking which is implemented by exploit a buffer overflow vulnerability on ARM. This method dynamically builds a white-list of legitimate branch target address before the target binary code execute,performs CFI enforcement to detect illegal control-flow transfer at run-time,analyzes the illegal branch target address to achieve exploit diagnosis. It implements the technique on a dynamic binary analysis platform for ARM-Linux systems. Results show that it can effectively detect the exploit and locates the attack vector.
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Computer Engineering. 2015, 41(3): 156-161. https://doi.org/10.3969/j.issn.1000-3428.2015.03.030Krill Herd(KH) foraging optimization algorithm is one of the most recent achievements in the field of bionic swarm intelligence. Despite high performance of KH,weak local searching ability and slow convergence speed are two probable deficiencies for solving some high-dimension and multi-modal function optimization. This paper proposes a greedy elitism crossover operator for accelerating convergence,utilizes one chaotic searching operator to escape some local optima based on self-logical mapping function,and employs an opposition searching operator to improve quality of initial population. A new improved KH algorithm combining such three operators is given. Simulation results on 7 benchmark functions show that the new algorithm has remarkable global optimizing ability and fast convergence speed, and outperforms the original KH algorithm and its newest variant algorithm.
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Computer Engineering. 2015, 41(3): 162-166. https://doi.org/10.3969/j.issn.1000-3428.2015.03.031This paper designs a quick solution to solve the simplified layered strong planning algorithm to increase the settlement efficiency. It is based on the introduction of greedy strategy,screening for non-target state for each action. This algorithm removes useless action plan for solving the strong solution to accelerate the state down search speed. On the basis of improved stratification, optimization and strong strategic planning solution, because the solution process is repeated,there are a lot of searching,and therefore the algorithm creates a collection to save the state having access to information,to avoid duplication of state search. After analysis,in the condition that the paths which are the intial state to goal state are overlapping,and the time complexity of this algorithm is O(nm),(n is the number of the initial state,m is the number of layers). The time complexity is O(m) in the condition that all the initial states to the target states are coincident. And the results are better than the ordinary forward search algorithm and reverse search algorithm.
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Computer Engineering. 2015, 41(3): 167-171. https://doi.org/10.3969/j.issn.1000-3428.2015.03.032The vibration state detection data from the centrifuge equipment in high-speed operation usually presents obvious nonlinearity,normal distribution and the characteristics of large sample,and random fluctuations in the data make it difficult to capture the trend characteristics. In this paper,time sequence theory is used to analyze the vibration signal data gathered from the running centrifuge equipment. It uses the quantile of the sequence data to build the feature vector according to the symmetrical principle,and introduces the Euclidean distance function to construct similarity measure,and then sets up the decision basis for pattern classification, realizes the pattern classification employing the k-means classification algorithm. Simulation results show that this method can effectively distinguish the partial load state and noload state of the centrifuge equipment,which is more accurate than that of wavelet analysis method.
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Computer Engineering. 2015, 41(3): 172-176,181. https://doi.org/10.3969/j.issn.1000-3428.2015.03.033Most present liquor classification methods need feature selection,but the feature selection algorithm will increase the computational complexity and limit the number of the characteristics. The selection result directly affects the recognition results. Therefore,this paper applies the Compressive Sensing(CS) theory into holistic analysis for Time-offlight Mass Spectrometry(TOFMS) of liquor. Using the training data to form the over complete dictionary and taking it as a sparse matrix,the Gaussian random matrix builds the measurement matrix. By calculating the minimum l1 norm solution,it obtains the sparse representation of the liquor aroma,then realizes liquor aroma recognition based on the KNearest Neighbor(KNN) algorithm. Combining four reconstruction algorithms with minimum residual error and KNN classify liquor aroma,experimental results show that it is feasible to use CS for classification of liquor aroma,and it can avoid the problem of feature selection. Using Sparsity Adaptive Matching Pursuit ( SAMP ) to solve l1 norm and recognition with KNN has a accuracy rate about 91. 45% and better stability.
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Computer Engineering. 2015, 41(3): 177-181. https://doi.org/10.3969/j.issn.1000-3428.2015.03.034In order to solve the problem of community mining optimization from complex network,according to the prior knowledge of the topology structure of complex network,a complex network community mining algorithm based on Particle Swarm Optimization(PSO) is proposed. In the proposed algorithm,particle’s position and velocity are redefined in discrete case,particle’s update principles is redesigned,the proposed algorithm can automatically determine the best community numbers without knowing it in advance. In order to improve the global search ability of the proposed algorithm,a local search operator is designed,and this operator can help the algorithm to jump out of local optimum and improves the convergence speed. Experimental results demonstrate that the proposed algorithm can efficiently dig out the community structures hidden behind complex networks,and the execution speed is much faster than that of iMeme-net algorithm.
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Computer Engineering. 2015, 41(3): 182-185. https://doi.org/10.3969/j.issn.1000-3428.2015.03.035The traditional interactive Genetic Algorithm ( GA ) can make user fatigue on optimizing the implicit performance index which affects the optimization quality and optimization efficiency. It is necessary to enhance the performance of interactive GA in order to apply it to complicated optimization problems successfully. The uncertainty of individual fitness is calculated based on the evaluation difference between the adjacent individuals;the convergence rate is abstracted according to the biggest information differences in evaluation sequence which reflecting the convergence of evolutionary population. Based on these,the probabilities of crossover and mutation operation of evolutionary individuals are presented. It makes the results more objective by guiding the evolutionary strategy through user preference information,and it allows a better exploration of the searching space and gives better findings compared with the traditional interactive GA(T-IGA).
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Computer Engineering. 2015, 41(3): 186-190. https://doi.org/10.3969/j.issn.1000-3428.2015.03.036In order to quickly and correctly retrieve the desired image from massive face image database,this paper proposes an efficient fast method for similar face image retrieval. It extracts Local Binary Pattern(LBP) features of face images and does dimensionality reduction by mapping the features from Euclidean space into Hamming space. A signature for each image is constructed by encoding dimensionality reduced features,using enhanced multi-bit encoding method. The similarity between each signature is judged by Manhattan distance instead of Hamming distance. It constructs inverted indexes from image signatures and fast retrieval is accomplished by using efficient inverted indexes. Experimental results on dataset containing 200 000 face images show that the retrieval time is less than 0. 15 s,which satisfies the retrieval precision as well as the accuracy and real-time of large-scale face image retrieval.
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Computer Engineering. 2015, 41(3): 191-197,210. https://doi.org/10.3969/j.issn.1000-3428.2015.03.037To control particles to fly inside search space and deal with the problems of premature convergence of Particle Swarm Optimization(PSO) algorithm,based on the comparative study of boundary mutation strategy proposed by scholars at home and abroad,this paper proposes an improved PSO algorithm,called double restriction mutation strategy. When particle tends to leave the search space,in view of the different situation for direction of velocity and position,the strategy controls the particle in the search space effectively,mainly by limiting to updating the position while updating the speed of the particle. This paper lists the performance comparison of four kinds of boundary mutation strategy and this strategy. Experimental studies through five test functions show that the double limit mutation strategy proposed in this paper has faster convergence speed. It is more effective to solve the problem of particle bound. Furthermore,this paper tests the relationship between maximum speed and position on the boundary mutation strategy by experiment. The result shows that the ratio of particles’ maximum speed and position is inversely proportional to the good or bad degree of the mutation strategy. It provides a basis for the study of boundary mutation strategy.
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Computer Engineering. 2015, 41(3): 198-203,217. https://doi.org/10.3969/j.issn.1000-3428.2015.03.038Aiming at the realization of quantitative decision of uncertainty analysis and intelligent processing for raw sensor data fusion in Wireless Sensor Network(WSN),a model of multi-layer Agent data fusion type Wireless Sensor Decision Network(WSDN) is proposed. On the basis of the hierarchical data fusion mechanism in WSN,such intelligent technique characteristics as decision table and decision network of rough set theory are introduced to design intelligencebased Agent and rule-based Agent and thus construct the model,and the multiplicity of inter-layer intelligence Agentbased WSDN and inter-attribute rule Agent-based WSDN is studied. Application results show that WSDN can be better applied to the typical situations of WSN,and thus achieves the fusion optimization and intelligent decision among Agent.
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Computer Engineering. 2015, 41(3): 204-210. https://doi.org/10.3969/j.issn.1000-3428.2015.03.039At the parameter estimation stage of the image classification method based on the traditional Visual Language Model(VLM),the distribution of visual words is usually analysed via maximum likelihood estimation,which ignores the adverse effect of image background noise. In view of the problem,an image classification method of weighted VLM for saliency map is put forward. The salient regions and background regions are extracted via saliency detection algorithm based on visual attention,the visual documents of images with salient labels are constructed,and the salient weights and conditional probability are estimated in the training phase. The images are classified with weighted VLM for saliency map. Experimental results show that,this method can effectively reduce the influence of image background noise,and enhances the discrimination performance of visual words,so as to improve the performance of image classification based on VLM.
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Computer Engineering. 2015, 41(3): 211-217. https://doi.org/10.3969/j.issn.1000-3428.2015.03.040A new method is presented to improve traffic sign detection with cooperation of color,shape and scale features,especially under conditions of color distortion,shape deformation and scale variance. Color enhancement maps are generated from traffic scene images. Regions of interest are then extracted from the color enhancement maps using multiple thresholds of color, chain codes of the curvature histograms of closed contours are calculated and scale normalized for the contours. The Support Vector Machine(SVM) classifier is applied to classify the chain codes of the extracted traffic signs and the template signs. Experimental results demonstrate that this method is capable of improving traffic sign detection,with low time complexity.
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Computer Engineering. 2015, 41(3): 218-222. https://doi.org/10.3969/j.issn.1000-3428.2015.03.041Feature extraction is the most important technology in content-based 3D model retrieval. This paper proposes an algorithm for feature extraction based on curvature features of 3D triangle model. The curvature of 3D model can become the sum of Gaussian curvature and mean curvature. So it is a blend of the Gaussian curvature and mean curvature. It can estimate the curvature of 3D model’ s vertices through the discrete differential geometry,and build a feature vector of 3D model. Experimental results show that the algorithm of this paper is better than the average curvature or Gaussian curvature as the feature vector.
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Computer Engineering. 2015, 41(3): 223-227,236. https://doi.org/10.3969/j.issn.1000-3428.2015.03.042With regard to the absence of base models which are extendible in the field of image analysis,an image granule labeling model is proposed. On the analysis of the applicability of rough sets and quotient space,two new concepts,semantic granule and conception granule,are defined and the image labeling model based on granules is constructed with them. A linear algorithm,Image Granule Labeling(IGL) algorithm,is presented for the realization of the granule labeling model with the definitions of connected segment in a line and potential connection range between two lines. It simplifies connectivity determination using a dynamic set of provisional labels and takes into account the fact that the quantity of granules may be huge and the structure of granules is very complex normally. Comparisons and experimental results on binary images and color images show that the proposed granule labeling algorithm is effective and accurate,and it is quicker than conventional labeling algorithms.
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Computer Engineering. 2015, 41(3): 228-236. https://doi.org/10.3969/j.issn.1000-3428.2015.03.043The Multipole diffusion model is a simple model that well describes light scattering in translucent materials. However,it is not well suited for very thin medium,particularly those close to or thinner than one Mean Free Path (MFP). This paper tries to extend the Multipole diffusion model for very thin medium with reasonable accuracy. It reviews the Multipole diffusion model and its assumptions,and to relax one of the assumptions by separating the direct transmitting component and the diffuse component of light. It adjusts the way the Multipole model places its point light sources to better match characteristics of light transport in thin medium. The diffuse part of the light is calculated using the modified source placement,and the direct transmitting part is approximated using a Dirac delta distribution. To evaluate the accuracy of the extended model,it is compared with the classical Multipole and Monte-Carlo simulations. The resulting profiles is predicted by the three models,as well as actual renderings. It is shown that the classical Multipole model is unable to compute profiles correctly for materials close to or less than one MFP thick. The extended model matches Monte-Carlo results better than the classical Multipole model. The extension of the current Multipole diffusion model proposed is suitable for medium close to or thinner than one MFP,and matches the Monte-Carlo method with reasonable accuracy. It can be easily integrated with existing Multipole implementations.
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Computer Engineering. 2015, 41(3): 237-241. https://doi.org/10.3969/j.issn.1000-3428.2015.03.044The technique of 3D human facial animation can be applied in a wide range of fields such as virtual reality, avatar control and so on. This paper proposes a real-time facial animation system based on Kinect. In this system,facial expression parameters are inferred by facial tracking client with Kinect and sent to the facial animation synthesizing server through socket. The server looks up FaceDefTables based on MPEG-4 facial animation standard to control the morphing of 3D face model. 3D facial animations which emulate expressions of the user are then generated in real time. Experimental results show that the method can rebuild quality realistic 3D facial animations in real time. Compared with existing technologies,this system with simple structure is easy to deploy and is also extendibility.
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Computer Engineering. 2015, 41(3): 242-246. https://doi.org/10.3969/j.issn.1000-3428.2015.03.045A novel target tracking method for target’s localization with mean shift based on multiple features and least squares method prediction is proposed to solve background interference,problems of partial occlusion and other issues.Aiming at the problems of background interference,the Improved Gaussian Mixture Model(IGMM) is proposed to build background model and to extracted foreground moving object. The motion information,color information and texture information are fused to represent the target,according to the change of the target and backgrounds,combined with the motion feature to remove noise interference of background and to locate the object. In the occlusion process,when the mean shift integrating multi-feature fails to track the target,it can use least squares method to predict the location of the target. Experimental results demonstrate that the method can track the target accurately and has better robustness in complex backgrounds or occlusion situations.
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Computer Engineering. 2015, 41(3): 247-252. https://doi.org/10.3969/j.issn.1000-3428.2015.03.046A Visual Attention Mechanism(VAM) based multi-scale image fusion algorithm is proposed in this paper, which tries to overcome the inconformity between fusion rules and observer′ s visual characteristics. Visual saliency matching coefficients based on visual attention mechanism are computed and employed in Wavelet Transform (WT) approximate coefficient fusion. In WT detail coefficient fusion,select-max rule with directional consistency checking is used. A fusion performance evaluating method based on the comparison of visual saliency is proposed to measure visual consistency between source images and fused results. Experimental results demonstrate the superiority of the proposed algorithm in terms of subjective visual similarity and objective quantization comparison.
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Computer Engineering. 2015, 41(3): 253-257. https://doi.org/10.3969/j.issn.1000-3428.2015.03.047Aiming at the problem that the current image semantic segmentation algorithm at pixel level is difficult to use global shape features,leading the fuzzy contour of object and some wrong recognitions. This paper presents a new regional level image semantic segmentation algorithm based on texture element block recognition and merging. This algorithm uses the texture element feature to segment objects with a clear outline,which fully considers the relationship between adjacent pixels and keeps corners and edge information between objects. Experiments conducted on the MSRC database show that this method can segment and recognize a variety of semantic. Besides,it has the advantages of high efficiency,high recognition rate and good segmentation effect.
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Computer Engineering. 2015, 41(3): 258-261. https://doi.org/10.3969/j.issn.1000-3428.2015.03.048To solve the problem of blendshapes generation mostly depending on manual modeling and fine-tuning,this paper proposes an automatic generation method about example-based expression blendshapes. Using a set of generic face models as the prior,it makes each generated blendshapes approach to its real semantics. Expression blendshapes generated by this method can map semantics and expression dynamics from the generic model to the target model. The method achieves model’s scalability in application and enables users to gradually calculate more expression models according to their own needs. Experimental results show that the method,constructing a gradient space to optimize blendshapes, outperforms the state-of-the-art methods both in speed and reality.
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Computer Engineering. 2015, 41(3): 262-268. https://doi.org/10.3969/j.issn.1000-3428.2015.03.049It is not easy for conventional X-ray absorption contrast based Computed Tomography ( CT ) imaging technique to get a high quality image from the weak absorption materials comprising of light elements. X-ray phase contrast CT imaging is a CT imaging technique aiming at weak absorption materials and possessing ultrahigh resolution. However,X-ray phase contrast CT imaging takes too long time and requires too high X-ray radiation dose,which can set back the promotion of clinical applications. So it has significant meaning to study the image reconstruction for phase contrast CT using few projection views. This paper is under the theory of Compressed Sensing(CS),uses refractive angle information,aims to reduce the X-ray radiation dose,proposes a X-ray phase contrast CT image reconstruction algorithm. Experimental results show that compared with Filtered Back-projection (FBP) algorithm,this algorithm can use few projection views to obtain reconstructed images of higher quality,and can get higher Peak Signal to Noise Ratio(PSNR) and numerical accuracy in the actual data experiment.
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Computer Engineering. 2015, 41(3): 269-272,277. https://doi.org/10.3969/j.issn.1000-3428.2015.03.050In order to achieve high capacity reversible sensitive image information hiding,this paper presents a lossless hiding algorithm of high capacity based on the difference between adjacent pixels for image. By the image block,and difference value of each block is calculated by different scanning order,choosing the difference value histogram of best scan order by comparing difference value sequence. Select the two largest peak points from the differerce histogram,and the nearest multiple zero points in each peak point,and insert several bit secret information in pixel of peak point,which achieves high capacity reversible image lnformation hiding. The results of simulation experiment show that the algorithm can select the best scan order by pixels distribution of each block image dynamically and using two peaks and multiple zero to embed secrets. It improves capacity of embedding secret information greatly, besides PSNR is ideal after embedding secret information.
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Computer Engineering. 2015, 41(3): 273-277. https://doi.org/10.3969/j.issn.1000-3428.2015.03.051To use comprehensively different transport modes and combined transport are effective to decrease transportation cost and time. Therefore,this paper provides a solution for the combinational optimization of multiple transport modes. The solution selects comprehensively transport modes,logistics suppliers and transport routes on the premise of meeting transportation need. This paper integrates the optimization selection of multiple transport modes and path selection,establishes the route optimization model for multitasking from one origination to one destination in the fourth Party Logistics(4PL),and proposes the solution of Max-Min Ant System(MMAS). The results of experiments show that,the route optimization problem based on the selection of multiple transport modes in the 4PL can be solved by MMAS conveniently and effectively,which can be consulted by 4PL companies.
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Computer Engineering. 2015, 41(3): 278-282,286. https://doi.org/10.3969/j.issn.1000-3428.2015.03.052HDF4 files are used to store the data of Moderate-resolution Imaging Spectroradiometer(MODIS) products, and it can store various types of data,but its data structure is complex. At present,the function libraries of HDF4 file which are developed by HDF GROUP can only be used in Fortran and C language,other programming languages lack the method of reading and writing HDF4 file systematically. Although ArcGIS supports most of the raster data,it does not support multiple data sets hierarchical storage of HDF data format. This thesis designs a middleware based on C# language of operating HDF4 file,and it solves some problems such as ArcGIS unable to create multiple datasets HDF4 file,and it introduces the core idea and the concrete application of the middleware instances. This middleware is applied in environmental protection of the ecological environment of remote sensing products production system project,and it solves some problems such as C# language unable to create multiple datasets HDF4 file when handing MODIS product data,and it verifies the practicality.
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Computer Engineering. 2015, 41(3): 283-286. https://doi.org/10.3969/j.issn.1000-3428.2015.03.053The downlink capacity performance of Distributed Antenna System(DAS) is investigated over composite fading channels. Based on this,the ergodic capacity of DAS with Transmit Antenna Selection ( TAS ) is analyzed. According to the capacity performance analysis,an approximate closed-form expression of the average channel capacity is derived by employing numerical integration formulas. It can avoid inaccuracy of existing capacity expression which is obtained by means of log-normal approximation. Simulation results show that the derived expression can match the simulation well,and thus it can evaluate the capacity performance of DAS downlink effectively.
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Computer Engineering. 2015, 41(3): 287-291. https://doi.org/10.3969/j.issn.1000-3428.2015.03.054Time-frequency ratio is the ratio of mixed signals’ amplitudes in time-frequency domain. The inversion of the matrix composing of the corresponding time-frequency ratios which is gotten from single source points in mixed signals can obtain the estimate of the source signals. Blind source separation based on time-frequency ratio has a large amount of calculation and small number of effective time-frequency windows after transforming the signals to the timefrequency domain. Time-frequency bins comprising the repeating patterns have similar values at each period. According to this characteristic,analysis zones including a repeating period are used to detect single source points instead of the whole time-frequency domain. Using similarity coefficient matrix as the separation effect standard,simulation experimental results show that the proposed method can reduce 45. 43% of time with the same separation accuracy.
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Computer Engineering. 2015, 41(3): 292-297. https://doi.org/10.3969/j.issn.1000-3428.2015.03.055When emergencies occur in the buildings,in order to monitor the evacuation objects and reduce location updates frequency,a hybrid location update strategy is proposed enriched by the velocity,direction properties of the evacuation objects and the topological,semantic structure of the indoor landmark unit. This strategy guarantees that the object is updated in crowded or landmark unit, and it reduces a few positioning errors due to indoor positioning uncertainty. As demonstrated by the experiments,compared with existing update strategies based on the fixed time or safety area,under the premise of meeting the location accuracy,this strategy keeps track of evacuated objects’ detailed positioning information and crowded conditions with less communication cost.
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Computer Engineering. 2015, 41(3): 298-302. https://doi.org/10.3969/j.issn.1000-3428.2015.03.056Regional computer interlocking system is implemented with the method of dispatching supervision and centralized interlocking. The extension of physical media is used for regional control of its security communication network. The real-time requirement of security protocol is gradually increasing with the large number of adjacent sites incorporated into the system. This paper analyzes the transmission delay of Controller Area Network(CAN) bus(used for existing regional computer interlocking system communication network ) between stations, and proposes a dynamic priority algorithm to improve the real-time performance. The simulation result shows that the improved CAN bus protocol can reduce the maximum delay between nodes by changing the load. In addition, it can ensure the real-time performance of different types of nodes, and can meet the requirement of regional computer interlocking system for network communication.
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Computer Engineering. 2015, 41(3): 303-305,311. https://doi.org/10.3969/j.issn.1000-3428.2015.03.057Regarding the security problem of information transmission in mobile terminal,this paper proposes a best matching steganography scheme,Matching steganography scheme Least Histogram Abnormality(M-LHA) based on Least Histogram Abnormality(LHA),and a model of information hiding system based on Android platform. M-LHA steganography preprocesses the secret information by replacement algorithm,and selects the swap that best matches the carrier image for steganography. It is proven that M-LHA algorithm has better relative entropy and more stable histogram distribution in comparison with the traditional LHA steganography algorithm,which can bring the effective improvement in the imperceptibility of steganography system. The information hiding system also meets the safety requirements for mobile terminal users.
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Computer Engineering. 2015, 41(3): 306-311. https://doi.org/10.3969/j.issn.1000-3428.2015.03.058The traditional accounting systems cannot support 10 Gigabit wire speed and they do not support one account multiple connections and real-time flow step accounting. A new ten Gigabit dual stack authentication and accounting system is designed and implemented,which improves the accounting algorithm model to realize real-time flow step accouting and optimizes the generic PC server’s architecture to improve the forwarding performance of ten Gigabit billing gateway. The campus network application shows that it can provide real-time charging in ten Gigabit dual stack link and fast forwarding service.
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Computer Engineering. 2015, 41(3): 312-316. https://doi.org/10.3969/j.issn.1000-3428.2015.03.059The azimuth accuracy of High Frequency Surface Wave Radar (HFSWR) is very low,especially for long distance target,which can seriously affect the accuracy of tracking over-the-horizon targets. Aiming at this problem,a high frequency ground wave bi-station system with no bearing based on high-parameterized Extended Kalman Filtering (HPEKF) is proposed. The system implements tracking target in three dimensions, using only range and doppler measurements of two radar stations combining with HPEKF. This method ignores the azimuth information of radar measurements,which solves the problem of inaccurate angle measurement for the far distance target, extends the application environment of the algorithm. The simulation result in computer verifies the feasibility and validity of the algorithm.
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Computer Engineering. 2015, 41(3): 317-320. https://doi.org/10.3969/j.issn.1000-3428.2015.03.060While enhancing the immersion of touch-based interaction,large touchscreen yet shows some limitations due to the short distance between user and the large screen. In order to improve user experience,this paper tries to combine gesture interaction and large touchscreen with two interaction modes based on the distance between user and screen. A survey is performed through a test system which combines both gesture interaction and large touchscreen technology. Statistical results indicate that gesture interaction is beneficial to large touchscreen display,which proves the practical value and research significance of this study.
2024
Volume 50 No 4
Volume 50 No 4
(Started in 1975, Monthly)
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428