• Korean Journal of Cognitive Science
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• v.10 no.4
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• pp.51-62
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• 1999

This paper proposes a fuzzy Petri net representation to represent the fuzzy production rules of a rule-based expert system. Based on the fuzzy Petri net representation. we present a fuzzy reasoning algorithms which consist of forward and b backward reasoning algorithm. The proposed algorithms. which use the proper belief evaluation functions according to fuzzy concepts in antecedent and consequent of a fuzzy production rule. are more closer to human intuition and reasoning than other methods. The forward reasoning algorithm can be represented by a reachability tree as a kind of finite directed tree. The backward reasoning algorithm generates the backward reasoning path from the goal to the initial nodes and then evaluates the belief value of the goal node using belief evaluation functions.

• The KIPS Transactions:PartD
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• v.13D no.1 s.104
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• pp.111-116
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• 2006

Given a state, it is essential to for the finite state model analysis (such as model checking) to decide whether or not the state is reachable. W a site of the model is small, the whole state space is to be explored exhaustively. However, it is very difficult or even impossible if a size of the model is large. In this case, the model can be reduced into a smaller one via abstraction which does not allow e false positive error. this paper, we devise such an abstraction and apply it to the Nemorize game solving. As a result, unsolved game due to the state explosion problem is solved with the proposed abstraction.

• The Transactions of the Korea Information Processing Society
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• v.2 no.1
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• pp.45-54
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• 1995

Retest arises when attemptint to validate code modifications. This paper proposes a retest methodology which explicitly defines the amount of retesting to be performed for any given code change. In order to minimize the objective function, we use the set/use matrix through analysis of data dependence as well as the connectivity, reachability, and test case/reference matrix through program control flow analysis. The value of objective function will give the minimum number of test cases necessary to assure the proposed methodology, we develope the retesting tool for generating mininum test cases based on the function.

• Journal of KIISE:Software and Applications
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• v.37 no.9
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• pp.669-675
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• 2010

For detecting requirement errors in early system development phase, the behaviors of a system should be described in formal methods and be analyzed with analysis techniques such as reachability analysis and cycle detection. However, since they are usually based on explicit exploration of system state space, state explosion problem may be occurred when a system becomes complex. That is, the memory and execution time for exploration exponentially increase due to a huge state space. In this paper, we analyze the fundamental causes of this problem in concurrent systems and explore the state space without composing concurrent state spaces for reducing the memory requirement for exploration. Also our new technique keeps a visited history minimally for reducing execution time. Finally we represent experimental results which show the efficiency of our technique.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1392-1398
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• 2008

This paper presents a Petri Net (PN) based disassembly sequence planning model with precedence operations. All feasible disassembly sequences are generated by a disassembly tree and a disassembly sequence is determined using the disassembly precedence and disassembly value matrix, The precedence of disassembly operations is determined through a disassembly tree and the value of disassembly is induced by economic analysis in the end-of-life phase. To solve the disassembly sequence planning model with precedence operations, a heuristic algorithm based on PNs is developed. The developed algorithm generates and searches a partial reachability graph to arrive at an optimal or near-optimal disassembly sequence based on the firing sequence of transitions of the PN model. A refrigerator is shown as an example to demonstrate the effectiveness of proposed model.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.300-301
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• 2018

Recently, various payment services using mobile terminals are emerging and many users are using this service. This study is an empirical study on the effect of system factors(convenience, reachability, compatibility) of mobile simple payment service on trust, positive affect, mediated by customer perceived risk. A survey was conducted for this study, and a structural equation model was analyzed with PLS. Results showed that convenience, accessibility, and compatibility affect risk, and risk affects trust and positive affect.

• The Journal of Korean Association of Computer Education
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• v.13 no.5
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• pp.81-90
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• 2010

Cloud computing is an Internet-based computing paradigm that provides services in a virtualized form composed of plenty of resources sharable. In Cloud computing environments, gossip protocols are engaged as a method to rapidly disseminate the state information for innumerable resources. Although gossip protocols provide a robust and scalable multicast, there is a drawback that requires redundant messages in satisfying 100% of reachability. In our study, we propose a Group-based Gossip Multicast Protocol in order to reduce the message overhead while delivering the state information efficiently. Furthermore, we verified the performance of the proposed protocol through experiments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.209-212
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• 2011

Triangulation is a typical method to locate or identify the location, which requires inherently at least three pre-recognized reference points. In some cases, owing to out of reachability to communication facility the target node can not reachable always to three base stations. This paper presents a predictive method, which can estimate the location of the moving target node in real time even though the target could not get in touch with all three base stations. The method is based on the PID-controlled Moving Objects Spatio-Temporal Model Algorithm. This can predict the moving direction of the moving target, and then combine with the past target position information to judge accurately the location.

• Journal of Communications and Networks
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• v.3 no.4
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• pp.342-350
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• 2001

The Internet routing instability, or the rapid fluctuation of network reachability information, is an important problem currently facing the Internet engineering community. High levels of network instability can lead to packet loss, increased network latency, and delayed routing convergence. At the extreme, high levels of routing instability can lead to the loss of internal connectivity in wide-area networks. In this paper, we investigate the variation of domain degree and domain count of the inter-domain network over time by using linear regression model in order to analyze the topology variation of inter-domain network. We Also propose an efficient policy management model to reduce the instability in the inter-domain routing system. The proposed model can be used to identify whether a routing policy is adequate to reduce convergence time that is required to return to a normal state when BGP routing instability happens. Experimental analysis shows that the proposed model can be used to set up routing policy in domains for the purpose of minimizing the effects and the propagation of BGP routing instability.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.8 s.350
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• pp.77-83
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• 2006

In this paper, we have pesented a reliable data transfer mechanism using Directed Diffusion in WSNs (fireless Sensor Networks). This mechanism involves selecting a route with higher reachability and transferring data along the route chosen, which is based on the end-to-end reliability calculated by the dissemination procedure of Interest packets, while each node of a sensor network maintains the only information on its neighborhood. We performed various experiments changing the link error rates and the number of nodes and discovered that this proposed mechanism improves event-to-sink data transfer reliability in WSNs. We also found that this mechanism spreads traffic load over and reduces energy consumption, which in turn prolongs network lifetime.