• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.454-457
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• 2003

대규모 시스템 명세의 올바름을 검증하기 위한 유한상태 LTS(Labeled Transition System)에 기반을 둔 CTL(Computation Tree Logic) 논리 적용의 문제점은 시스템 내부의 병렬 프로세스간 상호 작용으로 인한 상태폭발이다. 그러나 medal mu-calculus 논리를 시스템 안전성 및 필연성 특성 명세에 사용하면, 행위에 의한 순환적 정의가 가능하므로 상태폭발 문제가 해결된다. 본 논문에서는 LTS 로 명세화 된 철도 신호제어용 프로토콜 모델의 안전성 및 필연성 특성을 모형 검사 기법에 의해 검증하기 위해 시제 논리로 사용된 modal mu-calculus를 사용하여 해당 검정 알고리즘을 구현 및 적용하였다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.424-425
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• 2008

This paper presents application of RCM(Reliability Centered Maintenance) in waterworks system. The reliability-based probability model for predicting the failure probability is established and FTA(Fault Tree Analysis) is proposed to considering RCM. To calculate failure probability, Weibull distribution is usually used due to age related reliability. FTA is an engineering analysis which is using logic symbols. The real historical data of CMMS(Computerized Maintenance Management System) make full use of case study for waterworks system. Consequently, the RCM would be likely to permit utilities to reduce overall costs in maintenance and improve the total benefit.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.4 no.2
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• pp.193-198
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• 2004

This paper describes an automatic finite element (FE) mesh generation for three-dimensional structures consisting of tree-form surfaces. This mesh generation process consists of three subprocesses: (a) definition of geometric model, (b) generation of nodes, and (c) generation of elements. One of commercial solid modelers is employed for three-dimensional solid structures. Node is generated if its distance from existing node points is similar to the node spacing function at the point. The node spacing function is well controlled by the fuzzy knowledge processing. The Voronoi diagram method is introduced as a basic tool for element generation. Automatic generation of FE meshes for three-dimensional solid structures holds great benefits for analyses. Practical performances of the present system are demonstrated through several mesh generations for three-dimensional complex geometry.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.10 no.3
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• pp.165-169
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• 2010

This study seeks to find the factors associated with social workers' turnover intention and show us how to manage turnovers by looking for some rules affecting turnover intentions. Our investigation surveying 331 social workers reveals that social workers' turnover intentions are affected by organizational commitment, job satisfaction, and burnout. Our pattern analyses using fuzzy ID3 show that the higher their commitment, the higher their job satisfaction stemming from promotion opportunities, rewards, and personal relations with peers and bosses. In addition, turnover intentions decreases (even if burnouts--the job-related stress--are very serious) when organizational commitment increases. We come to understand that organizational commitment could be a more important variable than job satisfaction and burnouts. Such results suggest that it would be necessary to consider how to improve social workers' organization-wide commitment rather than satisfaction and burnout related to jobs and environments.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.12 no.4
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• pp.308-318
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• 2012

Captions include information which relates to the images. In order to obtain the information in the captions, text extraction methods from images have been developed. However, most existing methods can be applied to captions with a fixed height or stroke width using fixed pixel-size or block-size operators which are derived from morphological supposition. We propose an edge connected components based method that can extract Korean captions that are composed of various sizes and fonts. We analyze the properties of edge connected components embedding captions and build a decision tree which discriminates edge connected components which include captions from ones which do not. The images for the experiment are collected from broadcast programs such as documentaries and news programs which include captions with various heights and fonts. We evaluate our proposed method by comparing the performance of the latent caption area extraction. The experiment shows that the proposed method can efficiently extract various sizes of Korean captions.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.13 no.3
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• pp.200-207
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• 2013

Petri Nets are a system description and analysis tool. Reachability is one of the most basic properties in Petri Net research. In a sense, reachability research is the foundation study for other dynamic properties of Petri Nets through which many problems involving Petri Nets can be described. Nowadays, there are two mature analysis methods-the matrix equation and the reachability tree. However, both methods are localized, i.e., it is difficult to find a general algorithm that can determine reachability for an arbitrary Petri Net, especially an unbounded Petri Net. This paper proposes and proves three propositions in order to present a subclass of a Petri Net, the live single-branch Petri Net, whose reachability is equivalent to the satisfiability of the state equation.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.349-351
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• 2005

자가 적응 시스템을 무인 시스템(UWS: Unmanned Weapon Systems)에 적용하기 위한 다양한 연구가 이루어지고 있다. 자가 적응 시스템은 임무중인 시스템이 다양한 주변 환경 및 시스템의 변화에 따라 능동적으로 시스템 또는 임무수행을 위한 전략을 주정해 항상 최상의 성능을 발휘할 수 있도록 하는 능력을 갖춘 시스템을 말한다. 자가 적응 시스템에서 능동적으로 변화시킨 시스템의 아키텍처나 임무수행 전략이 유효한 것인지에 관한 검증을 수행한 후 시스템에 적용해야 한다. 기존의 대부분의 자가 적응 시스템에 대한 연구결과에서는 능동적으로 변화된 시스템이 임무수행에 적합한지에 대한 검증 방법을 제시해 주고 있지 않다. 본 연구에서는 UWS의 자가 적응 시스템이 임무수행 중 변화 되었을 때 미래의 발생할 사건에 대해 적절하게 적용 가능한지를 검증하기 위하여 시간적인 사건의 완전성을 검증하기에 적합한 Computation Tree Logic(CTL) 모델체킹(Model Checking)을 적용하여 자가 적응 시스템의 적응결과를 검증하는 방법을 제시하였다.

• Proceedings of the Safety Management and Science Conference
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• 2010.04a
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• pp.573-585
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• 2010

최근 철도차량은 안전성과 신뢰성 향상을 위해 점차 복잡하게 설계 제작되고, 품질에 대한 기대와 요구수준이 점차 높아짐에 따라 운영기관에서는 과학적이고 체계적인 예방 정비를 통한 안전성과 가용성 향상을 위해 노력하고 있다. 이러한 목적을 달성하기 위하여 여러 방안들이 연구되고 있으며, 대표적으로 신뢰성 기반 유지보수(RCM; Reliability Centered Maintenance)가 철도분야에 지속적으로 도입되고 있는 추세이다. 본 연구에서는 새로운 예방정비 기술로 대두되고 있는 RCM의 기본이론에 대한 고찰과 RCM의 일반적 실시 절차를 소개하고, RCM의 국제규격인 IEC 60300-3-11, NAVAIR 00-25-403, MIL-STD-2173을 비교 분석하여 이를 바탕으로 철도차량에 RCM 도입 시 효과적이고 적합한 절차 및 방안을 제시하고자 한다.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1964-1967
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• 2002

Recently design verification have been played an important role in the design of large scale and complex systems. In this article, we especially focus on model checking methods. Behaviors of modeled systems are generally specified by temporal formulas of computation tree logic. However. Users must know well temporal specification because the specification might be complex. We proposed method that temporal formulas are gained inductively and amounts of memory and time are reduced. Finally, we will show verification results using our proposed method.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.2
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• pp.38-49
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• 1997

In this paper, w describe partitioning large circuits into multiple chips on the programmable FPCB for rapid prototyping. FPCBs consists of areas for FPGAs for logic and interconnect components, and the routing topology among them are predetermined. In the partition problem for FPCBs, the number of wires ofr routing among chips is fixed, which is an additonal constraints to the conventional partition problem. In order to deal with such aconstraint properly we first define a new partition problem, so called the topologybased partition problem, and then propose a heuristic method. The heuristic method is based on the simulated annealing and clustering technique. The multi-level tree clustering technique is used to obtain faster and better prtition results. In the experimental results for several test circuits, the restrictions for FPCB were all satisfied and the needed execution time was about twice the modified K-way partition method for large circuits.