• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.2
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• pp.238-247
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• 2023

Liquefied petroleum gas (LPG) is an attractive fuel for ships considering its current technology and economic viability. However, safety guidelines for LPG-fueled ships are still under development, and there have been no cases of applying LPG propulsion systems to small and medium-sized ships in Korea. The purpose of this study was to perform an objective risk assessment for the first marine LPG engine system and propose safe operational standards. First, hazard and operability (HAZOP) analysis was used to divide the engine system into five nodes, and 58 hazards were identified. To compensate for the subjectivity of qualitative evaluation using HAZOP analysis, fuzzy set theory was used, and additional risk factors, such as detectability and sensitivity, were included to compare the relative weights of the risk factors using a fuzzy analytical hierarchy process. As a result, among the five risk factors, those with a major impact on risk were determined to be the frequency and severity. Finally, the fuzzy technique for order of preference by similarity to ideal solution (TOPSIS) was applied to select the risk rank more precisely by considering the weights of the risk factors. The risk level was divided into 47 groups, and the major hazard during the operation of the engine system was found through the analysis to be gas leakage during maintenance of the LPG supply line. The technique proposed can be applied to various facilities, such as LPG supply systems, and can be utilized as a standard procedure for risk assessment in developing safety standards for LPG-powered ships.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.160-162
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• 2000

데이터베이스에 대하여 아무런 지식이 없는 일반인도 데이터베이스를 쉽게 검색할 수 있도록 언어변수를 사용한 질의 및 질의 확장에 의한 효율적인 데이터베이스 검색 시스템을 설계한다. 언어 변수의 퍼지와 및 질의 확장을 위해 퍼지 소속함수, 개념 계층, 유사 관계 등을 적용하며, 한의원 데이터베이스를 사례로 하여 프로토타입을 구현하고 실험 및 평가를 한다.

• Archives of design research
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• v.13 no.1
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• pp.131-138
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• 2000

The evaluation of design is one of the most important steps in design process. However, because in most cases, design evaluation has been disregarded in comparison with other steps and has been performed by designer's subjective judgment. there are few studies for the development of systematic methodology. In this study, we developed the method of design evaluation using the fuzzy theory and the multi-criteria dedsion making model. This method consists of two steps. The first step is to obtain relative importance weights of design evaluation criteria, and the second step is to obtain and integrate scores for design evaluation criteria. AHP(analytic hierarchy process) and fuzzy theory were applied to the first and the second step, respectively. We applied the developed method to the sensible evaluation of cellular phone design. As the result, we verified that the developed method could be effectively used in the evaluation of product design.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.227-227
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• 2012

본 연구는 수자원계획 문제에서 다기준 의사결정기법을 적용할 때 발생할 수 있는 두 가지 문제에 대해 분석하였다. 첫 번째는 다기준 의사결정기법 선택의 차이가 결과에 어느 정도 영향을 미칠 수 있는지를 제시하였고 두 번째는 평가기준에 대한 가중치와 대안들의 평가치에 대한 불확실성을 최소화하기 위해 민감도 분석을 수행하는 절차를 제시하였다. 첫 번째 문제를 위해 가중합계법, Compromise Programming, 계층화분석과정, 수정된 계층화 분석과정, 가중곱방법, TOPSIS, ELECTRE-2, Regime 방법을 사용하였다. 또한 최근 사용빈도가 높은 삼각형 Fuzzy 숫자와 다기준 의사결정기법을 결합한 기법에 대해서도 분석하였는데 Fuzzy WSM, Fuzzy 계층화분석과정, Fuzzy 수정 계층화분석과정, Fuzzy TOPSIS, Fuzzy Compromise Programming을 검토하였다. 분석결과 평가기준에 대한 가중치 조건과 표준화 방법이 동일한 상황에도 불구하고 조금씩 다른 순위를 제시하는 것으로 나타났다. 또한 다양한 MCDM 기법들을 적용해도 동일한 순위로 나타나는 대안들이 있었다. 따라서 다기준 의사결정기법을 사용한 수자원 관리계획을 수립할 때에는 다양한 분석기법을 활용해서 기법의 선택으로 인한 불확실성을 최소화해야 한다. 두 번째 문제는 평가기준에 대한 가중치와 대안의 효과 정량화 자료의 불확실성을 극복하기 위해 각각에 대한 민감도 분석을 수행하였다. 본 연구는 유량확보와 수질개선을 위한 수자원 계획 수립을 위해 가중합계법을 이용한 문제에 두 경우의 민감도 분석을 모두 수행하였다. 이 과정에서 결정계수와 민감도 계수를 산정하여 이용하였다. 본 연구는 향후 수자원 관리 및 계획 분야에서 다기준 의사결정기법을 적용할 때 사용될 수 있는 기초 가이드라인이 될 것이다.

• Journal of the Korean Institute of Intelligent Systems
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• v.10 no.2
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• pp.83-93
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• 2000

This paper proposes the use of the analytic hierarchy process(AHP) controller for obtaining optimal cycle time of traffic intersection signal. By means of simulations that have data from expert traffic estimators, the performance of AHP controller is compared with a fixed-time controller and fuzzy controller. A simulation was executed using data obtained from many expert interviewer of Ansan City hall rotary. The principal issue is how AHP controller algorithm can aid traffic signal supervisor to construct an expert system for traffic intersection signal control. This paper has two steps: (I) we shall present a new methodology based on the work of Satty for calculating a scale of importance of each of the objectives, (2) we also consider that the human's decision mechanism is represented by approximating reasoning where the fuzzy integral is used.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.11a
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• pp.112-115
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• 2007

본 논문은 퍼지추론을 통해 개체의 유사성과 적합도의 종합적 평가를 이용한 유전알고리즘의 선태연산자를 제안한다. 단일 집단을 가상적으로 임의의 n 개의 개체군을 나누고, 개체의 적합도와 유사도에 기반한 퍼지추론을 통해, 효율적인 계층화를 구성하고자 한다. 동시에 점진형(steady-state) 진화방식과 결합시켜 계층화된 군집내에서 개체들이 조기에 수렴하는 현상을 방지해 줄 수 있도록 하고, 적은 개체를 이용하여 효율적인 진화가 가능하도록 구현하였다. 2가지 기만적 문제에 대해서 다른 선태 연산자들의 결과와 비교하였으며, 만족할만한 성능을 얻었다.

• Journal of the Korean Institute of Intelligent Systems
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• v.10 no.3
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• pp.218-227
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• 2000

In this paper, we present a new fuzzy information retrieval method based on thesaurus. In the proposed method th thesaurus is represented by a fuzzy linguistic matrix, where the elements in fuzzy linguistic matrix represent a qualitative linguistic values between terms. In the fuzzy linguistic matrix, there are three kinds of fuzzy relationships between terms, i.e., similar relation, hierarchical relation, and associative relation. The implicit fuzzy relationships between terms are inferred by the transitive closure of the fuzzy linguistic matrix based on fuzzy theory. And the proposed method has the capability to deal with a qualitative linguistic weights in a query and in indexing of information items to reflect qualitative measure of human based on vague and uncertain decisions rather than a quantitiative measure. Therefore the proposed method is more flexible than the ones presented in papers[1-3]. Moreover our method is more effectual of time than the ones presented in papers[1-3] because we use a fuzzy linguistic matrix and AON (Associate Ordinary Number) values in query evaluation process. As a result, the proposed method allows the users to perform fuzzy queries in a more flexible and more intelligent manner.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.2 s.29
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• pp.155-160
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• 2007

This paper aims to evaluation of order for allocation of rescue unit using Analytic Network Process. For evaluation, in this paper, assess about person, ship and environment related risk by fuzzy logic and AHP(Analytic hierarchy Process). Also, quantity and quality operation efficiency assess by DEA(Data Envelopment Analysis) and Liquate scale. finally total weight calculate by ANP. At the result, Rescue Units of MP, YS RCC/RSC is order higher. Thus, it needs to have more rescue ships and rescue devices for relieving the risk in the future.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.245-251
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• 2006

This is paper aims to evaluate allocation order of SRU using Analytic Network Process. For evaluation, in this paper, assess about person, ship and environment related risk by fuzzy logic and AHP(Analytic hierarchy Process). Also, quantity and quality operation efficiency assess by DEA (Data Envelopment Analysis) and Liquate scale. finally total weight calculate by ANP. At the result, Rescue Units of MP, YS RCC/RSC is order higher. Thus, it needs to have more rescue ships and rescue devices for relieving the risk in the future.

• Journal of Korea Society of Industrial Information Systems
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• v.16 no.4
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• pp.107-117
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• 2011

Smartphones are widely used as a mobile communication devices with more advanced computing ability and connectivity than a contemporary feature phone. As the market expands, many brand-new smartphones are released and chosen by (potential) smartphone users. In spite of smartphone's popularity, little research of the factors affecting the evaluation of smartphones and their influences on smartphone choice have been performed. Therefore, we aim to analyze evaluation factors of smartphone selection and use in this research. We use Fuzzy Analytic Hierarchy Process method, a Multi-Criteria Decision Making (MCDM) model, to find the relative importance among the factors considering the fuzziness of pair-wise comparison using AHP. After reviewing related works and interviewing the focus group, we extract the five independent factors influencing the choice and use of a smartphone. Pair-wise comparison and triangle fuzzy numbers are used to calculate the relative importance of factors. We analyze not only the whole interviewees' responses, but the differences between smartphone users and non-users. Practical implications are delivered in concluding remarks.