Started in January,1974(Monthly)
Supervised and Sponsored by Chongqing Southwest Information Co., Ltd.
ISSN 1002-137X
CN 50-1075/TP
CODEN JKIEBK
Editors
Current Issue
Volume 41 Issue 7, 14 November 2018
  
SIMPLE:A Novel Multi-paradigm Programming Language
WU Di,CHEN Lin and XU Bao-wen
Computer Science. 2014, 41 (7): 1-8.  doi:10.11896/j.issn.1002-137X.2014.07.001
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Because modern static languages become increasingly complicated with too many extended constructs,we wanted a language with simple core concepts and wide applications.Therefore,we designed SIMPLE,a high-level programming language that possesses concise key concepts and abundant language constructs.We first introduced SIMPLE in a nutshell.Then some illuminating ideas on modular programming,generic programming,garbage collection,and exception handling were proposed.In addition,we discussed how to integrate procedure oriented programming,object oriented programming,functional programming paradigms in the design of SIMPLE.
Excursive Measurement and Analysis of Normal Cloud Concept
XU Chang-Lin and WANG Guo-yin
Computer Science. 2014, 41 (7): 9-14.  doi:10.11896/j.issn.1002-137X.2014.07.002
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Cloud model integrates fuzziness and randomness of the qualitative concepts in the natural language,and rea-lizes the mutual transformation between concept’s intension and extension by forward cloud transformation and backward cloud transformation.The normal cloud based on normal distribution and Gaussian membership function has universality.In this paper,an excursive measurement based on outer envelope curve of normal cloud concept was defined by KL divergence,which is a non-symmetric measure of the difference between two probability distributions.Finally,based on the characteristics of human cognition,some simulation experiments were designed to study and analyze the excursion during the process of concepts’ cognition in a calculation way.
Comprehensive Cognition Emotional Theory—A New Mind Computing Model
PU Jiang
Computer Science. 2014, 41 (7): 15-24.  doi:10.11896/j.issn.1002-137X.2014.07.003
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This paper attempted to establish the basis for theoretical framework of comprehensive cognitive emotion.Firstly,a new mind computing model-multi-level needs-cognitive-emotional model was proposed.Based on absorbing information and knowledge from research fruit of emotional motivation-information theory,Maslow's hierarchy of needs theory and PAD dimensional emotion theory,this paper defined the different time node of information and emotions(a priori,a posteriori,actually obtained and expected parameters),focused on analysis of two-tier interaction mechanisms of information-emotional and intellectual-emotional,analyzed information,knowledge and cognitive mechanism,emotional formation mechanism,established information -emotional and intellectual -emotional interaction mechanism model,derived the corresponding interactive theorem which reveals the rich and complex human cognitive-affective interaction laws,and based on the corresponding relationship of basic emotions with PAD value,analyzed 14kinds of emotional feelings PAD value calculation,including the emotional state of the mechanism of formation and migration,and analyzed emotional state migration process from surprise to delight,gave examples to prove applications of cognitive emotion theory.Comprehensive cognitive emotion theory is a new mechanism of cognitive emotion interaction.
Research of Software Fault-tolerance Based on Monitoring of CPU Utilization Ratio
WANG Xiao-Gang and CAO Dong
Computer Science. 2014, 41 (7): 25-29.  doi:10.11896/j.issn.1002-137X.2014.07.004
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In hard real-time system,overtime of task running can induce a disastrous consequence of system performances.To enhance reliability and fault-tolerant ability of system,some software fault-tolerance strategy must be used.CPU utilization ratio of system is a key characteristic,which tells whether system is normal or not.Time feature and task state can be shown by CPU utilization ratio.Because of characteristic of CPU utilization ratio and demand of fault-tolerance,machine cycle was selected as measurement baseline.There are great differences when different monitor cycle is selected.Conditions of judging CPU utilization ratio anomaly in system were presented.Four measures that refer to structural redundancy and time redundancy were designed to handle this case.The simulation shows that software fault-tolerance based on monitoring of CPU utilization ratio can enhance reliability and fault-tolerant ability of system effectively.
Design and Implementation of File Prefetching Module Oriented to Distributed File System
SHI Ming,LIU Yi and TANG Ge-shi
Computer Science. 2014, 41 (7): 30-35.  doi:10.11896/j.issn.1002-137X.2014.07.005
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How to provide a stable and efficient file I/O performance for the upper application and computing,is the performance research hotspot oriented to distributed file system.This paper analyzed the mechanism in the design of the distributed file system on the common features,presented a general-purpose file prefetching heuristic module,and selected HDFS platform system to implement.The heuristic file prefetching module services the upper application and accomplishes the implementation in the internal of distributed file system,using the method of establishing prefetching thread pool within the file system,and the data not block as prefetching unit.This idea has certain universality,and is suitable for a variety of distributed file systems.Experimental results show that the heuristic file prefetching method can enhance the distributed file system I/O performance effectively.
Research of Lower Power Oriented Way-adaptive Partition Algorithm in Shared Cache of CMP
FANG Juan,WANG Shuai and YU Lu
Computer Science. 2014, 41 (7): 36-39.  doi:10.11896/j.issn.1002-137X.2014.07.006
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Improving processor performance and reducing energy consumption of the Cache have become research topic of the next-generation processor.To reduce energy consumption in CMP,a new mechanism based on dynamical way-adaptable Cache can be adopted.The mechanism mainly consists of way reallocate module and dynamic power control module.Way reallocate module reassigns ways between cores based on thread’s working set on the execution of the program.Our mechanism implements low power consumption by dynamic power control module.The proposed scheme based on dynamical way-adaptable Cache is implemented and simulated by Simics.We applied several programs selected from SpecOMP as benchmarks.Compared with traditional cache(Conventional L2Cache,C-L2),its IPC increases by 9.27%,and power consumption reduces by 10.95%.
Review of Reliability Analysis Based on Petri Nets
FANG Huan,FANG Xian-wen and WANG Li-li
Computer Science. 2014, 41 (7): 40-44.  doi:10.11896/j.issn.1002-137X.2014.07.007
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The research of reliability is important in safety-critical systems,and formal modeling and dynamic behaviors descriptions can be realized by Petri nets.Firstly,as for the research of reliability based on Petri nets,the basic methods and resolving processes were summarized and classified.Secondly,the methodology and procedures based on stochastic Petri nets were analyzed in detail,and as for the two kinds of systems,which are the Markov process equivalent systems and Non-Markov process equivalent systems,the analysis methods based on stochastic Petri nets were concluded,and their advantages and disadvantages were generalized.Furthermore,the advantages and disadvantages were analyzed in detail for reliability study by other types of Petri nets.Lastly,some common simulating platforms were summarized,and research directions in reliability analysis using Petri nets in future work were discussed.
Modeling and Performance Analysis of TTE Bus Based on DSPN
WANG Wang,YAO Shu-zhen and TAN Huo-bin
Computer Science. 2014, 41 (7): 45-48.  doi:10.11896/j.issn.1002-137X.2014.07.008
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The technology of Time-Triggered Ethernet(TTE) has been used in the new generation of aviation bus and developing at top speed,and the methods of modeling and performance analysis of TTE become an important meaning in its development of aerospace.Based on the working principle of message transmission of the TTE,this paper proposed a set of method of using Deterministic and Stochastic Petri Nets(DSPN) to model the TTE bus and do some related performance analysis,and also used a typical fire control system as an example for modeling and performance analysis,to illustrate the feasibility and effectiveness of the method.
Further Study of Relationship between Weak Fairness and Fairness of Petri Nets
SHI Zhou-qi,DING Zhi-jun and CHEN Hong-zhong
Computer Science. 2014, 41 (7): 49-51.  doi:10.11896/j.issn.1002-137X.2014.07.009
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In Petri net,the introduction of the concept fairness is to discuss the relationship of two transitions happened in net system.This relationship can well reflect whether each part of the concurrent system in the competition for resource has starvation-free problem.According to the definition and the relation of the weak fairness and fairness,it was proved that fairness can be deduced by weak fairness for a bounded Petri net and for two classes unbounded Petri net.Fairness cannot be deduced by weak fairness for other unbounded Petri net.
Petri Nets Based Reliability Evaluation of Service
XU Jia-jun and YAO Shu-zhen
Computer Science. 2014, 41 (7): 52-57.  doi:10.11896/j.issn.1002-137X.2014.07.010
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The research on Web service reliability has become a hot topic.This paper first studied structure associated service composition description language BPEL based on the Petri nets,while to the service interaction model,it mo-deled the interactive features in service composition by applying Petri net.It gave the definition of composited service Petri net,and builded the reliability evaluation model and method,containing structure associated evaluation method and interaction associated simplification and evaluation method.Finally,a case study about travel service system was given to indicate the usability and correctness of the method.
RoQ Defense Effect Evaluations Based on SPN Model
SHI Jiang-yong,XIAN Ming,WANG Hui-mei and LIU Jian
Computer Science. 2014, 41 (7): 58-61.  doi:10.11896/j.issn.1002-137X.2014.07.011
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To avoid the weakness of DoS attack,Reduction of Quality Attacks(RoQ) utilizes the security vulnerabilities in self-adaptive mechanism of network and terminal system by sending high strength pulse intermittently,thus reducing the service quality of victims.RoQ attacks are more elusive and efficient,which brings challenges to its detection and evaluation.Right now the defense technologies to RoQ attacks mainly include mending protocol,detection of attack flows’ features,self-adaptive detection and repairmen,and so on.This paper builded a Stochastic Petri Net(SPN) and used it in SPNP software to simulate the service quality changes in the process of attack and defense game.By evaluating the effects of different defense ways,this paper offered some consultancy for decision-makings in cyber defense activities.
Diagnosability Analysis of Fuzzy Discrete Event System Based on Extended Fuzzy Petri Net
SHE Wei,YE Yang-dong and CHEN Qian
Computer Science. 2014, 41 (7): 62-67.  doi:10.11896/j.issn.1002-137X.2014.07.012
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Aiming at the shortcomings of fuzzy finite automata and fuzzy Petri net in Fuzzy Discrete Event System(FDES) behavioral modeling,a kind of extended fuzzy Petri net(EFPN) was porposed.Based on EFPN,a FDES beha-vior model and system fault diagnosers were constructed.The key of the FDES behavioral modeling is a new event mo-del,and the probability distribution of next system state is calculated by the event trigger matrix of EFPN.It is showed that the expression ability of EFPN is stronger than classical fuzzy Petri net,when evaluating the effects of the events in which the synchronic distance is 0.In contrast,when a FDES contains more than one state component,the size of the EFPN model is far less than fuzzy finite automaton.According to a FDES behavior model based on EFPN,we could effectively construct the fault daignoser of the model by reachability graph,and analysed the diagnosability of the FDES model.
Research on Cognitive Model Based on Attribute Granular Computing
ZHOU Ru-qi and FENG Jia-li
Computer Science. 2014, 41 (7): 68-73.  doi:10.11896/j.issn.1002-137X.2014.07.013
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Attribute granular computing can simulate the cognitive functions of human brain,such as granulation,orga-nization and causation,but it lacks of a formal mechanism for the reasoning process.Petri net has asynchronous,concurrent and uncertainty characteristics,which is similar to the characteristics of some cognitive activities in human thinking process.The basic concept and logic calculation rules of attribute granular computing were put forward in this paper.The Petri net was properly extended based on qualitative mapping.Some basic elements of a cognitive system,such as knowledge representation,reasoning,learning and memory mode were initially showed in the extended Petri net.The results show that this method can reflect the cognitive process of uncertainty identification and judgment in a certain extent.This model provides a new convenient tool for Petri net in the study and stimulation of human’s advanced intelligence and image thinking.
Method of Main and Branch Road Adaptive Coordinate Control on Timed Petri Net Modeling
SUN Li,ZHANG Zhao-hui and CUI Xiang-ru
Computer Science. 2014, 41 (7): 74-76.  doi:10.11896/j.issn.1002-137X.2014.07.014
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In order to keep the high efficient access rate of the green wave and coordinate the reasonable traffic flows of the main road and the branch road,a method of main and branch road adaptive coordinate control on timed Petri net modeling was presented.According to the traffic flows of the main road,this method can change the phase time automatically.According to the phase time and the traffic flows of the main road,this method can also change the phase time of the branch road automatically.By analyzing this case,this method can achieve the adaptive coordinate control of the main road and the branch road effectively.Then,it makes the number of vehicles in the branch road passing the intersection as large as possible,and it can guarantee the smooth flow of the green wave band.Thus the method can improve the access efficiency of the intersections.
Method of Obligation Analysis of Change Region in Process Model Based on Petri Net Behavioral Pattern
YANG Yan,FANG Xian-wen and LIU Xiang-wei
Computer Science. 2014, 41 (7): 77-80.  doi:10.11896/j.issn.1002-137X.2014.07.015
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The obligation analysis of the change region in the interacted process model Petri nets is an important question of checking and evaluating consistency and compatibility of interacting models.The study of existing change region just deals with the method to find change region,and the obligation analysis is out of the range.Based on the concept of obligation and behavioral fragment pattern,an approach of obligation analysis of change region was proposed.By the application on the citing example,the validation of the approach was verified.
Study on Mechanism of Consistency Detection in BPEL Activities Authorization Coordination Based on CPN
SHANG Chao-wang,LIU Qing-tang,ZHAO Gang and TONG Ming-wen
Computer Science. 2014, 41 (7): 81-85.  doi:10.11896/j.issn.1002-137X.2014.07.016
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Mechanism of BPEL access control is one of focal points in Web services secure composition.It is a difficult problem to maintain the activities authorization constraint coordination.With the extended CPN(Colored Petri Nets) for modeling the dynamic behavioral semantics of BPEL activities execution,this paper used the method of coverability tree to analyze the fire sequence of model state transition,and implemented the dynamic consistency detection of activities authorization coordination.The paper provided theoretical foundation for the detection and optimization in the design of BPEL activities authorization coordination.At last,an example proved the efficiency of the mechanism.
Business Process Modeling and Analyzing Based on XAr/T-net
WANG Ying,LI Ji-hui and HUANG Zhen
Computer Science. 2014, 41 (7): 86-90.  doi:10.11896/j.issn.1002-137X.2014.07.017
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Petri net is an effective tool to describe and analyze business processes,but existing Petri net-based modeling approach can not reflect the flow of business data.Artifact is the key data entity in business processes and has complex nested structure.Artifact structure and operations were defined with graphical XML schema definition language.A computable model named XAr/T-net was presented based on the combination of XML document and process definition with Petri net.The business process structures and the Artifact features were analyzed using the coverability graph in Petri net.
Method of Optimal Path Selection Based on Modal Petri Net Branching Effective Range
FANG Xian-wen,TAO Xiao-yan and LIU Xiang-wei
Computer Science. 2014, 41 (7): 91-96.  doi:10.11896/j.issn.1002-137X.2014.07.018
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For adapting business needs,looking for optimal path of behavior execution in business process under beha-vior constraints has a certain practical significance.The existing proposed methods are to search the optimal path by optimization algorithms or behavior analysis on the basis of static analysis,ignoring the impact of behavioral constraints on the effectiveness of the execution behavior,thus have some limitations.On the basis of the existing methods,using the ordering relation of Petri nets behavior profile to describe constraints and determine behavioral effective ranges, this paper proposed a method of optimal path selection in business process based on modal Petri net branching effective ranges.This method uses behavioral effective ranges to substitute for the existing fixed value,so as to better describe behavior constraints of business processes and effective behavior under constraints.Finally,a specific case analysis was given out,which shows the proposed method is effective.
Research and Development of Cyber Net System Modeling Tool
WAN Jun,ZHAO Bu-hui and LU Ji-yuan
Computer Science. 2014, 41 (7): 97-101.  doi:10.11896/j.issn.1002-137X.2014.07.019
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Cyber net system is a subclass of Petri nets,which has the characteristic of nonlinear relation and a powerful modeling capability.A kind of computer modeling tool (CyberNetTool) was developed by using visual programming platform Visual Studio .NET.Users can interactively build Cyber net system model and use the PNML format file to store the model.Software core classes were designed to facilitate the interface controls management and model analysis.Implementation algorithms for property analysis modules and dynamic simulation module were described in detail.Finally,an application example was illuminated to show the correctness and availability of this tool.
Study on Activity-oriented Dynamic Access Authorization Model for BPEL4WS
SHANG Chao-wang,LIU Qing-tang,ZHAO Gang and TONG Ming-wen
Computer Science. 2014, 41 (7): 102-104.  doi:10.11896/j.issn.1002-137X.2014.07.020
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Business process access control mechanism is a difficult problem in Web services composition application.According to the current deficiency of research in BPEL4WS secure access control,an Activity-Oriented Dynamic Access Authorization Model for BPEL4WS(ADABM) was proposed.By dissolving the coupling relationship between the organization model and business process model,ADABM refines the BPEL4WS access permission to activity level.The users can obtain the Web services access authorizations only when the corresponding activity meets the security requirements in BPEL4WS execution session.The grants and revokes of the activity access authorization can be implemented along with the process context.At last,the paper also described the implementation architecture of ADABM in Web services secure composition.
Petri Net-and Concurrent Scheduling Marking Graph-based Modeling and Analysis of Concurrent Tasks Scheduling
HAN Yao-jun
Computer Science. 2014, 41 (7): 105-109.  doi:10.11896/j.issn.1002-137X.2014.07.021
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In cloud computing and grid computing environment,there is a need of powerful graphical and mathematics tools for modeling and analyzing concurrent tasks scheduling because these tasks have dynamic,distributed,and heterogeneous properties.Petri nets are promising tools for modeling and analyzing events that are characterized as being concurrent,asynchronous,and dynamic.The weighted timed Petri net(WTdPN) model for concurrent tasks was given in this paper.Reachable marking graph is a very important tool to analyze the dynamic properties of Petri nets,but the concurrent relation of transitions in Petri nets can not be represented by reachable marking graph.Especially,it is not convenient to analyze time performance of system modeled by Petri net for the reachable marking graph.This paper presented the concept of concurrent scheduling marking graph(CSMG) and gave an algorithm for constructing concurrent scheduling marking graph of WTdPN.Finally,we analyzed the time performance of parallel download system using CSMG of WTdPN.
Colored-Petri-Net-based Complaint Model for User-interactive Question Answering System
LI Yan-cheng,ZENG Qing-tian,LU Fa-ming and XUE Jie
Computer Science. 2014, 41 (7): 110-113.  doi:10.11896/j.issn.1002-137X.2014.07.022
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Due to users’ complaints arising from such problems as unfair compensation,user-interactive question answering systems are catching more and more attention.By analyzing the complaint process of a user-interactive question answering system,the formal complaint model was presented using Colored Petri Net.Then the established formal modelwas verified by employing CPN tools.Finally,the state space report of the established model was analyzed,so the correctness and other features of the system design were demonstrated.This proposed method has special significance to the comprehensive formal analysis of the user-interactive question answering system.
Research on OpenFlow Modeling Based on Hierarchical CPN
LI Hua,HE Nan,DONG Lu-lu and LV Liang-liang
Computer Science. 2014, 41 (7): 114-118.  doi:10.11896/j.issn.1002-137X.2014.07.023
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CPN is a formal method which has been adopted in a wide range of research and application especially applications of the network protocols and the industrial systems.OpenFlow is a new network transfer model,containing OpenFlow switch and controller.This paper first introduced the OpenFlow protocol and the CPN(Coloured Petri Nets),and then gave and introduced in detail the hierarchical CPN models of OpenFlow switch,controller,and its OpenFlow protocol.The working mechanism of OpenFlow was reflected fully.The selections of token and variable definitions were in consideration in detail in the process of modeling.The OpenFlow dynamic work process was described by execution of CPN model.There was a simple analysis to properties of the model by CPN Tools for its liveness and boundedness.Finally,the research work in the future was considered.
Analysis for Network Security by Stochastic Petri-net
JIAO Jian and CHEN Xin
Computer Science. 2014, 41 (7): 119-121.  doi:10.11896/j.issn.1002-137X.2014.07.024
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Network attack graph is an important means of network security.The traditional attack graph and the attack path solution are difficult to describe in terms of probability the influence degree of the attack probability and Defense Technology on the whole scheme.Using stochastic Petri-net theory,this paper presented conversion algorithm which can make attack graph to Petri network defense scheme.Using stochastic Petri-net model generated by the algorithm can implement parallel analysis of attack and defense process.Experimental results show that the method can quantify probability of attack process effectively,also can help to analyze the effect of different defense technology on the overall system security.
Verification and Analysis of SIP Protocol Based on Timed Colored Petri Nets
LIU Jing,YE Xin-ming and MA Yuan-fei
Computer Science. 2014, 41 (7): 122-129.  doi:10.11896/j.issn.1002-137X.2014.07.025
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SIP(Session Initiation Protocol) has been selected by 3G communication as a session control mechanism for the next generation mobile network,so it is quite significant to ensure that the protocol design and implementation is defect-free and runs steadily and reliably.Timed Colored Petri Nets(TCPN) has advantages of modeling and analyzing software systems with complicated and time-constrained behaviors.Thus,TCPN was well adopted in this paper to construct a hierarchical formal model for SIP protocol,and several model analysis techniques were used together to validate its design accuracy.Then,using regular expression,the model based protocol execution paths were completely analyzed,and certain deadlock scenarios were pointed out.Finally,we proposed novel and validated protocol design revisions to effectively improve the feasibility and the reliability for practical SIP applications.
Research on Malware Propagation Model for Wireless Ad hoc Network
GAO Wei-min,ZHU Ling-zhi and LIANG Jun-bin
Computer Science. 2014, 41 (7): 130-134.  doi:10.11896/j.issn.1002-137X.2014.07.026
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Because of peer-to-peer system structure and node resources limitation, Ad hoc network faces more safety threat than the traditional network.In recent years,the malicious program research has become an international network and information security field forefront and one of the most active research directions in wireless network malicious programs,also a new research field of hot.We first analyzed the Ad hoc network architecture and security threats,common malware classification and the biological modeling propagation model,then from the SIR virus propagation model of differential equations of the model,aiming at problems for the model to use wireless Ad hoc network,through the introduction of network topology characteristics and immune delay and other concepts of malware propagation model,improved network topology,and combining the dynamic evolution of malware propagation process,designed an improved algorithm and dynamic immune strategy.Considering of the network virus propagation characteristics,network characteristics and immunization strategy,a simulation experiment analysis of the improved model was made.The experimental results show that both immunization strategy and node have effects on malware propagation.
Verification Method on CP-nets Concurrent Model
SUN Tao and YE Xin-ming
Computer Science. 2014, 41 (7): 135-139.  doi:10.11896/j.issn.1002-137X.2014.07.027
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It is very difficult to verify concurrency models based on CP-nets because of the state space explosion problem.A model reduction method based on concurrent attributes and a model abstraction method based on function combination were proposed for models.Model elements not associated with the concurrent property are removed,the abstraction level of the model is upgraded,the scale of state space is significantly reduced,and behaviors associated with the concurrent property are consistent with the original model.Verification methods,such as state space analysis and model checking,are used to check errors on the model,in order to modify errors in the original model .To some extent,the state explosion problem is avoided and model validation is accomplished.By applying above-mentioned method to HMIPv6protocol model,the validity of the method was verified.
Simulation and Optimization of Operational Supportability of Equipment Based on Petri Net Model
LUO Ming-lei,LI Yue and XU Yong-cheng
Computer Science. 2014, 41 (7): 140-142.  doi:10.11896/j.issn.1002-137X.2014.07.028
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The method of combining Petri net with Matlab was put forward based on the analysis of existing modeling and simulation methods,and was used to model and simulate the equipment supportability.As a result,the optimization of the supportive equipments and personnel was achieved,and the method put forward in this paper was validated.
Research of Translating UML Activity Diagram to Petri Net
ZHAO Jun-feng,ZHOU Jian-tao and XING Guan-nan
Computer Science. 2014, 41 (7): 143-147.  doi:10.11896/j.issn.1002-137X.2014.07.029
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Because Unified Modeling Language lacks formal semantics,the dynamic analysis and verification to UML based model are difficult to carry out.However Petri net not only has sufficient and rigid semantics,but also is equipped with precise analysis method.Comprehensive usage of Petri net and UML can efficiently improve the comprehensiveness,consistency,accuracy and completeness of the software model.The translation rules from UML activity diagram to Petri net were proposed.Then a translation tool called APConventer was implemented for translating activity diagram to Petri Net Markup Language.Activity diagram can be translated into Petri net and expressed in PNML effectively by the usage of the tool,so the UML model can be analyzed and verified better.
Graphical Reasoning Method to First-order Predicate Logic
GENG Xia,ZHANG Ji-jun and LI Wei-yan
Computer Science. 2014, 41 (7): 148-152.  doi:10.11896/j.issn.1002-137X.2014.07.030
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Traditional reasoning methods to first-order predicate logic have some problems such as inference inefficient,so a graphical reasoning method based on predicate/transition system was presented.The concept of predicate-and/or graph describing the and/or relation among predicates was presented,and several pre-and/or graph representations of predicate/transition system were defined.Finaly,a goal guiding graphical reasoning method adopting backward rea-soning way was put forward.This method has high efficiency and some advantages compared with other present reasoning methods.
Method for Modeling On-delay Timers in Ladder Diagrams Based on Ordinary Petri Nets
WEN Shi-gang,LUO Ji-liang,NI Hui-juan and CHEN Xue-kun
Computer Science. 2014, 41 (7): 153-156.  doi:10.11896/j.issn.1002-137X.2014.07.031
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The method was proposed for modeling an on-delay timer(TON) of programmable logic controller(PLC) as an ordinary Petri net.A boolean variable is represented by a pair of places,while an instruction to be executed in PLC is represented by a transition.Consequently,a TON is modeled by an ordinary Petri net.The results show that the beha-vior of a PLC system can be represented by the states of its Petri net model.Evidently,this method can be used for the formal design and verification of PLC programs.
GPU Based Image Feature Extraction and Detection
XU Jing,ZENG Miao-xiang and XU Wei
Computer Science. 2014, 41 (7): 157-161.  doi:10.11896/j.issn.1002-137X.2014.07.032
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As the performance of image detection method in the normal PC is not satisfactory nowadays because of the huge amount of high resolution image transmitting in current high-speed network,this paper presented a GPU-based solution for image extraction detection.We obtained feature extraction by using SURF(Speed Up Robust Features) algorithm and classified image features based on SVM(Support Vector Machine) algorithm.Furthermore,we utilized the parallelism of GPU float point arithmetic to optimize the system.As a result,the performance of GPU-based system achieves 5to 9times faster than the CPU-based system.
Multidimensional Node Reputation Management Scheme for Clustered Wireless Sensor Networks
FANG Fang,LI Jing-feng and LI Jie
Computer Science. 2014, 41 (7): 162-166.  doi:10.11896/j.issn.1002-137X.2014.07.033
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At present there are problems in reputation management mechanism for wireless sensor networks (WSNs),such as high cost of calculation,update and maintenance of reputation,poor resistance to “bad mouthing” and “ballot stuffing”.Taking the clustered wireless sensor network as the background,sensor nodes were divided into cluster head nodes and ordinary sensor nodes.According to the behaviors of sensor nodes on event perception,packet forwarding and data aggregation,a multidimensional node reputation management scheme was put forward.Applying the scheme to reactive multi-path routing protocol AOMDV,this paper proposed a reliable routing protocol called STA based on trusted nodes.The simulation results show that in distrusted environment,the proposed protocol improves the data forwarding rate and delivery success rate in WSNs.
Multi-zones and Multi-objectives Channel Allocation Protocol Based on TOA Real-time Geolocation System
HE Jie,XU Cheng,LIU Fei,LV Mo-wei and WANG Qin
Computer Science. 2014, 41 (7): 167-170.  doi:10.11896/j.issn.1002-137X.2014.07.034
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In order to meet the needs of real-time and dynamic joining of nodes in wireless real-time geolocation system,fully improve the channel utilization rate,this paper proposed a specific ZTDMA protocol that divides the geolocation system coverage area into several independent subdomain which can work in parallel.ZTDMA can shorten the average localization period of nodes effectively,and detect the joining and exiting of target nodes in time,dynamically allocate time slot for them,ensure real-time of the system.Then we simulated the ZTDMA protocol using OMNet++ simulation platform,in order to prove the superiority of real-time characteristic.
Heuristic QoS Routing Protocol for Wireless Sensor Networks
YU Miao,BAI Guang-wei,SHEN Hang,ZHANG Peng and CAO Lei
Computer Science. 2014, 41 (7): 171-175.  doi:10.11896/j.issn.1002-137X.2014.07.035
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This paper proposed a visual-queue-based service differentiation routing protocol(VSDR) for wireless sensor networks.VSDR uses aggregated weight,and takes queue length,geographic progress and residual energy of candidate downstream nodes into consideration when nodes select routing,in order to alleviate congestion in nodes and to balance traffic load in network.More importantly,different weight strategies are assigned for packets with different QoS requirements.In this way,we provided guarantee for delay of real-time packets and probabilistic guarantee for transmission opportunities of non-real-time packets.Our simulation results demonstrate that VSDR may deal with different ser-vices effectively,balance energy consumption of all nodes,prolong network lifetime, and adapt to reliability and delay requirements of applications.
Performance Analysis for Fragmentation and Assembly Algorithm of 6LoWPAN Adaptation Layer
LIU Qiao-shou,ZHANG-Wei,WANG Ru-yan and WU Da-peng
Computer Science. 2014, 41 (7): 176-180.  doi:10.11896/j.issn.1002-137X.2014.07.036
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In the perceptual layer of the Internet of Things,introducing IPv6protocol is the key research direction.The length of the data load between IPv6protocol and IEEE802.15.4protocol does not match that the upper level data packets can’t directly exchange data with the underlying protocol.The fragmentation and restructuration algorithm through adaptation layer protocol was used to solve the problem of payload length incompatibilities between the above two kinds of protocols.In order to analyse algorithm performance,fragmentation and assembly algorithm of 6LoWPAN,the improved fragmentation and assembly algorithm of 6LoWPAN and another improved fragmentation and assembly algorithm of 6LoWPAN combining each-hop ARQ algorithm were mathematically modeled and simulated.Firstly,fragmentation and assembly algorithms were simulated and analyzed through the network energy consumption and delay effects of the main performance indexes which contain bit error rate and the number of hop.Secondly,a novel adaptive algorithm framework which aims at optimizing network performance and saving network resources was proposed,so that the adaptation layer can choose different fragmentation and assembly algorithms under the changed network environment.
Network Connectivity Optimization Strategy Based on Wireless Techniques
SUN Chen,GUO Xiao-hui and FAN Yu-shun
Computer Science. 2014, 41 (7): 181-183.  doi:10.11896/j.issn.1002-137X.2014.07.037
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Network connectivity is the key indicator of the network survival ability and sustainment.In order to optimize the network connectivity,a connectivity optimization strategy based on wireless techniques was proposed.The strategy takes advantage of the flexibility of wireless link establishment.It first detects and measures the network in real-time,and then quantifies the network connectivity according to the above detections and measurements.When the network connectivity is below some threshold,the wireless link backup procedure is started,and the wireless backup construction algorithm is used to reduce the wireless resources needed to backup the links.The strategy tires its best to guarantee the network connectivity through these two procedures.Simulation results show that the proposed strategy can still guarantee the basic connectivity of the network when there are about 70% average link disruption.In the same network context,the proposed strategy can achieve 7%~9% more improvement of the network connectivity than the existing wired link backup scheme.
Cognitive Radio Spectrum Access Energy Efficiency Algorithm
CHEN Ming
Computer Science. 2014, 41 (7): 184-186.  doi:10.11896/j.issn.1002-137X.2014.07.038
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Cognitive radio technology and energy efficiency communication design have made system to respectively achieve high spectrum efficiency (SE) and energy efficiency (EE). However in the cognitive radio system, there is little research about not only keeping high spectrum efficiency,but also making the relatively high energy efficiency.Aiming at this problem,based on the orthogonal frequency division multiplexing (OFDM) cognitive radio network,considering the average energy efficiency and spectrum access scheme in spectrum efficiency to fold,this paper proposed a low complexity suboptimal heuristic algorithm.The simulation results show that the proposed algorithm can significantly save energy compared with other existing algorithms,and has a larger advantage in terms of performance and complexity.
Research on 3D Wireless Sensor Networks Energy Saving Routing Algorithm ISC-ODR
LI Zhan-guo,ZHANG Rui-zhe and WANG Yin-chuan
Computer Science. 2014, 41 (7): 187-189.  doi:10.11896/j.issn.1002-137X.2014.07.039
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The 3D wireless sensor networks routing algorithm Iterative Split Clustering Optimal Distance Routing(ISC-ODR) was proposed,and the design and calculation process was discussed theoretically.The simulating calculation under different topology shows that compared with the baseline algorithm,the ISC-ODR routing algorithm has good energy saving effect,can effectively prolong the survival time of the network.
Wireless Sensor Networks QoS Routing Algorithm Based on Improved Quantum-behaved Particle Swarm Optimization
PAN Guo and XU Yu-ming
Computer Science. 2014, 41 (7): 190-193.  doi:10.11896/j.issn.1002-137X.2014.07.040
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For further reducing energy consumption and delay time and prolonging the survival time of node in wireless sensor networks,an improved Quantum-behaved Particle Swarm Optimization algorithm was proposed,which is applied to QoS multicast routing problem in wireless sensor networks.The algorithm finds the optimal routing which meets the threshold limit by using the fitness function and global best position update method in wireless sensor networks.The comparison of simulation experiment shows that this algorithm achieves good results in saving energy consumption,controlling delay time and prolonging the survival time of the network node.
Risk Assessment Methods of Complex Network Based on GTST-MLD
LU Zhi-gang,LIU Jun-rong and LIU Bao-xu
Computer Science. 2014, 41 (7): 194-199.  doi:10.11896/j.issn.1002-137X.2014.07.041
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Aiming at the broblems that complex information systems have the high complexity,mutual influence and interdependence,and the existing risk assessment methods are difficult to adapt to large-scale network security risk assessment and application needs of practice,we researched risk factor analysis method and the overall risk assessment methods of complex information system based on GTST-MLD,including the study of complex systems model of accidents interdependencies,risk factors model and risk conduction analysis,which improves risk assessment capabilities and level of analysis for complex information system.The results prove that the model consolidates the security features of complex information system,such as objectives,functions,structure,behavior and so on,achieves security analysis at a higher level system functions,and provides a reliable means of quantitative analysis for complex information system risk assessment.
Proxy-based Security-feedback Trust Model in MP2P Network
CAO Xiao-mei,ZHU Hai-tao,SHEN He-yang and CHEN Gui-hai
Computer Science. 2014, 41 (7): 200-205.  doi:10.11896/j.issn.1002-137X.2014.07.042
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Trust problem is the key issue for Mobile P2P (MP2P) network security.In MP2P network,terminal devices’ addressing mode,communication mode and identifiers are different to traditional P2P network.Some security issues such as:allusion attack,malicious slander and collusion,“free ride” phenomenon,are even more serious compared to traditional P2P network.Aiming at these above issues,a Proxy-based Security-Feedback Trust Model (PSTM) was proposed in this paper.Different types of terminal devices access to different proxy servers to shield the discrepancy between different terminal equipments on MP2P device access network layer.Meanwhile,proxy servers can reduce the problem of single point failure with the method of related information’s backup and recovery.Certificate Feedback Ra-ter’s identification and qualification through security resource-selection protocol,then integrate trust information accor-ding to similarity of terminal and resource types with weighted method.Furthermore,set global contribution value and evaluation value in multi-granularity trust computation to motivate mobile peers’honest feedbacks.Divide mobile peer’s direct trust value into peer-oriented and resource-oriented values to make trust feedbacks more authentic.Simulation experiments show that PSTM can reduce malicious slander and collusion effectively.It also can restrain selfish peers’ free ride behaviors and increase successful cooperation rate of high-contributed peers in MP2P network.
Game Analysis on Statistical Characteristics Preserving Steganography
GAO Zhan-zhan,TANG Guang-ming and ZHANG Wei-wei
Computer Science. 2014, 41 (7): 206-209.  doi:10.11896/j.issn.1002-137X.2014.07.043
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In order to analyze security of statistical characteristics preserving steganography,two game models were established.They are different in strategies.One takes feature subsets as its strategies while the other’s strategies are steganography or steganalysis algorithms.In these two game models,payoff is the detection rate of steganalysis,and the divergence between feature subsets of two confrontation sides is used to reflect steganography algorithm's ability to resist statistical analysis.By equilibrium analysis on the models,optimal strategies to improve steganography system security were given in each case,and the expected payoff in equilibrium situations was also proposed.
Capabilities-based DDoS Defense Architecture for Future Internet
ZHANG Hong-hao,WANG Jin-song,HUANG Wei and ZHAO Xiang-lin
Computer Science. 2014, 41 (7): 210-215.  doi:10.11896/j.issn.1002-137X.2014.07.044
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Firstly,this paper introduced the theory and key technologies of Capabilities mechanism for future Internet and expounded and compared the typical programs based on Capabilities mechanism about their performance and reliability by simulation experiment in dissimilar scenarios.Secondly,we researched on the DDoS defense architecture based on capabilities mechanism,and discussed the viable implementation of the three parts(the flow classification,enforcement,Capabilities management) contained in the architecture in future network.Furthermore,we designed a simple traffic modeling under the Capabilities framework and analyzed the security and efficiency of the Capabilities framework theoretically.Finally,the paper analyzed the shortcomings and inadequacies of several solutions based on Capabilities mechanism and compared their performance and efficiency of in different scenarios through simulation experiments
Location Prediction of Moving Objects in Obstructed Space
LI Shi-ji,QIN Xiao-lin and SHI Jun-yan
Computer Science. 2014, 41 (7): 216-221.  doi:10.11896/j.issn.1002-137X.2014.07.045
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Most moving objects are typically influenced by obstacles.Recently,existing researches are mainly on range query,nearest neighbor query and spatial clustering query in obstructed space.However,there is no research on location prediction of moving object in obstructed space.This paper focused on location prediction of moving object in the pre-sence of obstacles.We proposed a efficient pruning method based on R-tree using gray model and line model.Conside-ring the trajectories of moving object are regular,we proposed several pruning strategies which can greatly reduce the number of searched obstacles.Finally,our experiment results demonstrate the accuracy and efficiency of the proposed approach.
Reliability Prediction Approach for Web Service Based on SOA
XIE Chun-li,YU Xi-meng and WANG Shu-qin
Computer Science. 2014, 41 (7): 222-226.  doi:10.11896/j.issn.1002-137X.2014.07.046
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In SOA,the precision ration of service discovery is the key factor in predicting service reliability.To improve the prediction accuracy of reliability for Web services,it is important to analyze the failure of service discovery.In this paper,firstly,the failure of service discovery was described and a discovery reliability model was built.Then,a new approach for predicting services reliability was proposed based on the discovery reliability.Lastly,an experiment was conducted and the influence of service discovery on service reliability was analyzed.The experimental results show that the new reliability approach is more appropriate for Web services.
Distributed Optimized Query Algorithm Based on SPARQL
WANG Jing-bin,FANG Zhi-li and ZHANG Yan-qin
Computer Science. 2014, 41 (7): 227-231.  doi:10.11896/j.issn.1002-137X.2014.07.047
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It’s a new way of solving the large amount of RDF(Resource Description Framework) query problem to use distributed technique to realize the SPARQL(Simple Protocol and RDF Query Language) Query.At present,most of the RDF queries based on Hadoop have to use multiple MapReduce jobs to complete the task,resulting in waste of time.In order to overcome this drawback,this paper proposed MRQJ(using MapReduce to the query and the join) algorithm to perform distributed SPARQL query.The algorithm can be divided into join plan generation and SPARQL query execution two parts:join plan generation uses greedy strategy to generate the most optimal join scheme,and only one MapReduce job should be done to get the query results in SPARQL query execution.The experiment on the LUBM test data set was made.The experimental results show that MRQJ method query efficiency is higher when the case of a query is more complicated.
Research on Processing Continuous Spatial Keyword Range Queries in Road Networks
LI Yan-hong,HUANG Qun,JIANG Hong and LI Guo-hui
Computer Science. 2014, 41 (7): 232-235.  doi:10.11896/j.issn.1002-137X.2014.07.048
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Compared with traditional location-based queries,spatial keyword queries can better meet the requirement of actual query processing.The paper addressed the issue of processing spatial keyword queries which consider both the distance and the keyword similarity of objects,and presented an efficient method to deal with continuous spatial keyword range queries in road networks(CRSKQ).A network model which considers the road segments,the objects,and the connectivity of the road network was proposed to support CRSKQ query processing.In order to continuously monitor the query result,a method which includes two phases,the initial query result getting phase and the continuous monitoring phase,was proposed.In the first phase,the initial query result objects can be found by road network expansion and keyword matching.In the second phase,the cost of continuous query monitoring can be greatly reduced by taking advantage of the query result of the previous time.Finally,experimental result shows the efficiency of our method.
Conditional Information Entropy Representation of Algebraic Reduction and its Efficient Algorithm
HUANG Guo-shun,ZENG Fan-zhi and WEN Han
Computer Science. 2014, 41 (7): 236-241.  doi:10.11896/j.issn.1002-137X.2014.07.049
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A semantic analysis on how to keep positive region unchanged was given.An improved conditional information entropy was proposed.It was proved that remaining the modified conditional information entropy unchanged and remaining positive region unchanged are equivalent.Therefore,some main concepts of algebraic reduction were described by the revised conditional information entropy.However,a counter example illustrates that its monotonicity does not hold,which means a heuristic reduction algorithm can not be constructed based on bottom-up.Any attribute in an algebraic consistent set is not irreversible if it is checked unsuppressible.An efficient algorithm based on top-down was proposed,which starts from condition attribute set,removes the unnecessary attribute step by step.It is finally guaranteed to obtain an algebraic reduction by traversing the attributes only once.Numerical example and the experimental results show that the algorithm is valid and efficient.
Finding Optimal Long Paths over Multi-cost Road Networks Using Bidirectional Searches
MA Hui,LI Jian-guo and LIANG Rui-shi
Computer Science. 2014, 41 (7): 242-245.  doi:10.11896/j.issn.1002-137X.2014.07.050
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Finding the shortest path is a classic problem in graph studies.Current researches mostly suppose that each edge in the graph has a single cost.However,in some cases,each edge might have multiple costs,which all have to be taken into consideration when computing the shortest path.A user defined aggregate function f is used to map the multiple costs of a path to a real number,from which the lengths of two paths can be compared.When f is not linear,the sub path of a shortest path is not necessarily a shortest path,and thus,most state-of-the art solutions can not be applied to this problem.This paper proposed a bidirectional search method that can find the optimal shortest paths.Experiments show that the proposed method is suitable for the long paths queries.Compared to the single directional search,the proposed method has high efficiency.Meanwhile,compared to the greedy algorithm which is based on the Dijkstra’s algorithm,the proposed method has high accuracy.
Novel Particle Swarm Optimization Algorithm Based on Fractional Calculus and Alpha-stable Distribution
LV Tai-zhi and LI Zhuo
Computer Science. 2014, 41 (7): 246-249.  doi:10.11896/j.issn.1002-137X.2014.07.051
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For the traditional particle swarm optimization(PSO) algorithm converges slowly and it is easy to fall into local minimum point,an improved PSO algorithm was proposed.The new algorithm combines memory character of fractional differential,reflects the historical information of particles’ movement and therefore improves the optimization process.Using Alpha-stable distribution instead of uniform distribution to generate random value can make the particle to escape from local minima in a certain probability and therefore there is more effective global search capability in new algorithm.Simulation results show that there is not only faster convergence speed and more effective global search capability under the single function in new algorithm,but also more satisfactory results under a complex and deceptive function.It is confirmed that the Alpha-stable distribution and fractional calculus can improve the performance of the PSO algorithm.
Knowledge Acquisition in Incomplete Information System Based on Formal Concept Analysis
LI Xiang,WANG Su-ge,LI De-yu,KANG Xiang-ping and ZHAI Yan-hui
Computer Science. 2014, 41 (7): 250-253.  doi:10.11896/j.issn.1002-137X.2014.07.052
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In practical applications,some common problems in information system can’t be solved effectively based on the classical rough set due to its incompleteness.To solve this problem,the paper introduced formal concept analysis into rough set,proposed a knowledge acquisition model in incomplete information systems by discussing the relationship between formal concept analysis and rough set theory.First by converting incomplete information system into a one-va-lued context,consistent concepts and consistent concept lattice were proposed.Then some common problems in incomplete information systems were studied,such as upper and lower approximations,cores,reducts,etc.Finally,the application of consistent concepts in a decision table was discussed.The proposed model not only explores the fusion of two theories greatly,but provides a new idea for solving some basic problems of incomplete information system.
Intenal-Outer Fusion of Attributes and Intelligent Digging-Seperation of Information
XU Feng-sheng,YU Xiu-qing and SHI Kai-quan
Computer Science. 2014, 41 (7): 254-260.  doi:10.11896/j.issn.1002-137X.2014.07.053
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P-sets(packet sets) are a dynamic mathematical model(a dynamic information model,or a dynamic data mo-del), while P-reasoning is a dynamic reasoning generated by P-sets.The attribute conjunctive normal form expresses logi-cal implication between elements and attributes in P-sets.By using crossing and permeating among P-sets,P-reasoning and attributes,the concepts of attribute internal fusion,attribute outer fusion and attribute internal-outer fusion were proposed.Furthermore,the theorems about attribute internal-outer fusion,and the relations between attribute internal-outer fusion and attribute conjunctive normal form were obtained.The extension-shrinkage relation theorem and intelligence generation of attribute internal-outer fusion were given.On the end,attribute internal -outer fusion was applied to information intelligent digging-seperation.In the fact,attribute fusionin including attribute internal fusion,attribute outer fusion and attribute internal-outer fusion is an important characteristics hidded in P-sets.
Approach for Development of Ant Colony Optimization Based on MapReduce
WANG Zhao-yuan,LI Tian-rui and YI Xiu-wen
Computer Science. 2014, 41 (7): 261-265.  doi:10.11896/j.issn.1002-137X.2014.07.054
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This paper discussed several parallel ways of ant colony optimization and their application scenarios as well as the feasibility of combination with the cloud computing framework MapReduce.Ant colony optimization with the local search feature was abstracted into several components,and then several interfaces based on MapReduce were built to implement each component.It provides a flexible,scalable solution for ant colony optimization with the local search feature to implement parallelism with the MapReduce framework.Finally,simulation results validate the proposed approach on the traveling salesman problem.
Adaptive CRBF Nonlinear Filter and its Improved Learning Algorithm
ZENG Xiang-ping,JIN Wei-dong,ZHAO Hai-quan and LI Tian-rui
Computer Science. 2014, 41 (7): 266-269.  doi:10.11896/j.issn.1002-137X.2014.07.055
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The traditional stochastic gradient algorithm uses squared error cost function based on second order statistics.It is difficult to achieve higher precision because it contains less information.To solve the problem,a new minimum exponential squared error adaptive learning algorithm was put forward.It uses exponential squared error cost function based on high order statistics,and combines the nonlinear adaptive filter based on convex combination of two RBF networks.The simulation experimental results of nonlinear system identification and nonlinear channel equalization show that the convergence performance of the improved algorithm is superior to the traditional stochastic gradient algorithm.
Expectation-based top-N Recommendation Approach for Improving Recommendations Diversity
LIU Hui-ting and YUE Ke-cheng
Computer Science. 2014, 41 (7): 270-274.  doi:10.11896/j.issn.1002-137X.2014.07.056
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Recommender systems are used to help users find relevant and personalized items from a large set of alternatives in many online applications.Most existing recommendation techniques are focused on improving recommendation accuracy.Recently,diversity of recommendations has also been increasingly recognized in research literature as an important aspect of recommendation quality.This paper proposed a novel top-N recommendations generated approach to improve aggregate recommendation diversity by controlling the recommended expectations of the global candidate items,which is available for recommendation in the top-N recommendations generating process.The proposed approach was evaluated using real-world movie rating datasets and different rating prediction algorithms.Results demonstrate the approach proposed in this paper can generate more diverse recommendations while maintaining an acceptable level of accuracy.
Bayesian Network-based Context-aware Recommendation Algorithm
HAI Ben-zhai and XIE Rui-yun
Computer Science. 2014, 41 (7): 275-278.  doi:10.11896/j.issn.1002-137X.2014.07.057
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Combining the context-aware recommender system with Bayesian networks,we proposed a context-aware recommendation algorithm,and designed a context-aware Resource Recommendation System Architecture.First using the Bayesian network,through computing the joint probability distribution of user access time and resource information,user interest of resources in the environment was obtained,and then the similarity of current user environment selected resources and past user environment selected resources was compared to provide appropriate resources list.Finally we compared the proposed algorithm with other common recommender system algorithms,and at the same time,the system architecture was modeled according to the M/G/1queue.The result proves the superiority and stability of our system architecture and the algorithm are better.
New Self-adaptive Cuckoo Search Algorithm
QIAN Wei-yi,HOU Hui-chao and JIANG Shou-yong
Computer Science. 2014, 41 (7): 279-282.  doi:10.11896/j.issn.1002-137X.2014.07.058
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In order to improve the local and global search ability of cuckoo search algorithm(CS) and its convergence rate,a new self-adaptive cuckoo search algorithm was proposed.In this algorithm,a self-adaptive parameter control strategy is used to adjust the step size of CS,thereby enhancing the search ability of CS.In addition,a mutation technique which is similar to differential evolution algorithm is utilized to guarantee the CS diversity.Experimental results show that the proposed algorithm is much more effective.
New Ensemble Learning Approach
GUO Hua-ping,YUAN Jun-hong,ZHANG Fan,Wu Chang-an and FAN Ming
Computer Science. 2014, 41 (7): 283-289.  doi:10.11896/j.issn.1002-137X.2014.07.059
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This paper proposed a new decision tree-based ensemble learning method called FL(Forest Learning).Unlike traditional ensemble learning approaches,such as bagging and boosting,FL directly learns a forest on all training examples as an ensemble rather than on examples obtained by sampling from training set.Unlike the approach of learning ensemble by independently training each classifier and combining them for prediction,FL learns each classifier considering its influence on ensemble performance.FL first employs traditional algorithm to train the first decision tree,and then iteratively constructs new decision trees and add them to forest.When constructing current decision tree,FL considers the influence of each partition on ensemble performance.Experimental results indicate that,compared to traditional ensemble learning methods,FL induces ensemble with much better performance.
Quasi-diagonal Matrix Hybrid Compression Algorithm and Implementation for SpMV on GPU
YANG Wang-dong,LI Ken-li and SHI Lin
Computer Science. 2014, 41 (7): 290-296.  doi:10.11896/j.issn.1002-137X.2014.07.060
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Sparse matrix-vector multiplication(SpMV) is of singular importance in sparse linear algebra,which is an important issue in scientific computing and engineering practice.Much effort has been put into accelerating the SpMV and a few parallel solutions have been proposed.In this paper we focused on a special SpMV,sparse quasi-diagonal matrix multiplication(SQDMV).The sparse quasi diagonal matrix is the key to solve many differential equation and very little research is done on this field.We discussed data structures and algorithms for SQDMV that were efficiently implemented on the CUDA platform for the fine-grained parallel architecture of the GPU.We presented a new diagonal storage format HDC,which overcomes the inefficiency of DIA in storing irregular matrix and the imbalances of CSR in storing non-zero element.Further,HDC can adjust the storage bandwidth of the diagonal to adapt to different discrete degree of sparse matrix,so as to get higher compression ratio than the DIA and CSR,reduce the computation complexity.Our implementation in GPU shows that the performance of HDC is better than other format especially for matrix with some discrete points outside the main diagonal.In addition,we combined the different parts of HDC to a unified kernel to get better compress ration and higher speedup ratio in GPU.
Outlier Detection Method Based on Constructive Neural Networks
ZHANG Xian-ji and WANG Lun-wen
Computer Science. 2014, 41 (7): 297-300.  doi:10.11896/j.issn.1002-137X.2014.07.061
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Outlier detection efficiency in data stream can be influenced by concept drift when there is noise.An outlier dynamic detection method based on constructive neural networks incremental learning was presented to solve this problem.The outline of the data in the sliding window is acquired,and the learning model is modified.On the other hand,data moving speed and flux can influence the efficiency as well.In this paper,the method of granular analysis was used to improve our method.The best analysis granularity in suitable sliding window was set to find outlier accurately.The simu-late experiment and the experiment of outlier detection in radio communication demonstrated the efficiency of this method.
Face Detection Based on SURF and Hough Forests
YAN Ming-jun,XIANG Jun,LUO Yan and HOU Jian-hua
Computer Science. 2014, 41 (7): 301-305.  doi:10.11896/j.issn.1002-137X.2014.07.062
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In order to realize the face detection and localization in complicated scenes,this paper presented an algorithm for face detection based on SURF (speeded up robust features) and Hough forests.SURF local features were adopted to construct a Hough forest classifier.Each leaf node stored the class information as well as the offsets from the locations of interest points to the centroid of the object,and the mapping relationship between local appearances of images and their Hough votings were established.The supervised and discriminative codebook was generated,which was used to estimate the object’s location via a probabilistic Hough voting,thereby improving the detection precision.Meanwhile,the algorithm reduced the computation and made the detection faster by using SURF local features.Experimental results demonstrated the efficiency of the proposed algorithm.
Harris Corner Detection Algorithm on OpenCL Architecture
XIAO Han,MA Ge and ZHOU Qing-lei
Computer Science. 2014, 41 (7): 306-309.  doi:10.11896/j.issn.1002-137X.2014.07.063
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Harris corner detection algorithm is widely used for extracting feature points in the field of computer vision.It is simple and stable,but inefficient.Currently most of the researches on algorithm optimization are aimed at a single hardware platform,and difficult to achieve the efficient running on different platforms.In this paper,parallel algorithm of Harris corner detection based on the core concept of Open Computing Language (OpenCL) was proposed,so that the whole image corner detection process can be implemented in OpenCL architecture.Finally,implementation of the parallel algorithm using mechanism of shared memory and constant memory and pinned host memory in Graphic Processing Unit (GPU) was detailed.The experiments show that the parallel algorithm of Harris corner detection based on OpenCL demonstrates substantial improvement up to 77times speedup than the serial algorithm running in the CPU,has high efficiency compared with CPU counterpart algorithm,and exhibits great potential for large-scale data processing in real-time processing.
Algorithm and Simulation of Image Stabilization for High Speed Moving Target Images Based on Adjacent Frames Compensation
JI Li-xia and LI Xue-xiang
Computer Science. 2014, 41 (7): 310-312.  doi:10.11896/j.issn.1002-137X.2014.07.064
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In the video image acquisition process for high speed moving object,the video and image shake due to high speed,wind and other factors.In order to improve the high speed moving target image acquisition performance of vision system,and improve the image quality,an improved algorithm of image stabilization for high speed moving target images based on adjacent frames compensation was proposed. We preprocessed the image by combining the gray histogram equalization method and adaptive filter, extracted the feature points in the video image through the scale invariant feature transform(SIFT) algorithm.And the affine model was used to solve the motion parameters.Kalman filter was used to scan the video image.Finally we used the adjacent frame compensation methods of a previous frame image as the reference frame of parameter compensation to the current frame,and the electronic image stabilization processing was realized.Simulation results show that the new algorithm can retain the features in the image while removing images shake and jitter,and is very suitable for electronic stabilization processing for high speed video image.The precision is improved and the computing consumption is reduced significantly.
Research on Algorithm for Real-time Recognition of Traffic Light Based on HOG Features
ZHOU Xuan-ru,YUAN Jia-zheng,LIU Hong-zhe and YANG Rui
Computer Science. 2014, 41 (7): 313-317.  doi:10.11896/j.issn.1002-137X.2014.07.065
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For the recognition of traffic lights in driverless cars,this paper proposed a real-time traffic lights detection and recognition algorithm based on HOG features and SVM.This algorithm extracts red and green areas in the video preciously,and then the eligible area will be screened.Hereafter the HOG features of all kinds of lights will be extracted.Finally this work use SVM to build the classifier of corresponding category lights.We can get the accurate real-time information based on the judgment of the decision function.The experimental results show that the algorithm has good accuracy and real-time performance.
Moving Target Detection Method Based on Gaussian Mixture Model
CHENG Quan and MA Jun-yong
Computer Science. 2014, 41 (7): 318-321.  doi:10.11896/j.issn.1002-137X.2014.07.066
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Based on Gaussian mixture model,this paper put forward an adaptive moving target detection algorithm.First of all,according to the intensity of pixel values of each pixel,the number of Gaussian distribution is adaptively selected to learn and update background model,again get difference image by background subtraction.Second,in the process of image binarization,an improved method of automatic threshold is proposed to separately classifly difference image pixels after threshold segmentation,so future goal can be obtained.Then the method of morphological reconstruction is adopted to effectively eliminate the shadow,significantly improving prospect target segmentation effect.Experiment proves that the method has good robustness and detection effect,as well as good adaptability.Especially when the grayscale change of detection target itself is large,the superiority of the algorithm is more obvious.
Brain Image Segmentation Method Based on FCM and Random Walk
GUO Peng-fei,LIU Wan-jun,LIN Lin,ZHAO Yong-gang and MIN Liang
Computer Science. 2014, 41 (7): 322-325.  doi:10.11896/j.issn.1002-137X.2014.07.067
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Random walk algorithm only considers the gray similarity of adjacent pixels,ignores neighboring pixels gra-dient information.This suppresses random walker walking to the seed point along some edges of similar gray to seed point,resulting in misclassification and missing points.This paper presented a segmentation method of brain image.It extracts image gradient information by using wavelet transform,and puts the gradient information into the edge weight.Finally using improved FCM algorithm,combining with the pixel neighborhood information,we obtained a final split brain image.Experimental results show that this method improves segmentation correct rate and the edge of the segmented image is smoother.