• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.3
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• pp.217-222
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• 2015

Clustering is one of important data mining techniques known as exploratory data analysis and is being applied in various engineering and scientific fields such as pattern recognition, remote sensing, and so on. The method organizes data by abstracting underlying structure either as a grouping of individuals or as a hierarchy of groups. Weather radar observes atmospheric objects by utilizing reflected signals and stores observed data in corresponding coordinate. To analyze the radar data, it is needed to be separately organized precipitation and non-precipitation echo based on similarities. Thus, this paper studies to apply clustering method to radar data. In addition, in order to solve the problem when precipitation echo locates close to non-precipitation echo, fuzzy logic based clustering method which can consider both distance and other properties such as reflectivity and Doppler velocity is suggested in this paper. By using actual cases, the suggested clustering method derives better results than previous method in near-located precipitation and non-precipitation echo case.

• Journal of Korean Society of Transportation
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• v.20 no.1
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• pp.65-76
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• 2002

This study is realized using fuzzy evaluation and AHP(the analytic hierarchy process) for the optimum search of traffic route and estimated by the quantitative analysis in the vague subjective judgement. It is different from classical route search and noticed thinking method of human. Appraisal element, weight, appraisal value of route is extracted from basic of the opinion gathering fur the driving expert and example of route model was used for the finding of practice utility. Model assessment was performed attribute membership function making of estimate element, estimate value setting, weight define by the AHP, non additive presentation of weight according to $\lambda$-fuzzy measure, Choquet fuzzy integral.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.387-392
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• 2008

본 논문에서는 에너지 절약을 위한 방법으로 여름철 냉방의 적정 온도 및 풍향을 제어하기 위한 가상의 시뮬레이션을 목적으로 열 영상과 퍼지 추론 규칙을 적용한 온도 및 풍향 제어 기법을 제안한다. 온도 제어를 위한 가상 시뮬레이션에서 열 영상을 분석하기 위해서 영상을 $300{\times}400$의 크기를 가지는 색상 분포 영상으로 변환한다. 색상 분포 영상은 Red, Magenta, Yellow, Green, Sky, Blue의 온도 값을 가지는 R, G, B 값이며 각 색상은 $ 24.0^{\circ}C$에서 $27.0^{\circ}C$의 분포의 온도 값을 가진다. 색상 분포 영상은 아래 계층부터 레벨1에서 레벨10의 높이 계층으로 분류한다. 분류한 각 계층은 고유의 색상 분포도를 가지며 색상이 가지는 온도 수치에 따라서 계층별로 온도를 구성한다. 풍향 제어를 위한 각 계층의 높이는 레벨1에서 레벨3까지는 하위층이며, 레벨 4부터 레벨 7은 중간층, 레벨 8부터 레벨 10은 상위층으로 분류한다. 각 계층의 온도와 높이 레벨 값은 온도 조절과 풍향의 우선 순위, 강도 조절, 지속 시간을 구하기 위한 파라미터이다. 실내 공간의 전체적인 온도의 균형과 풍향을 제어하는 과정으로 풍향의 방향, 지속시간을 적용하고 풍향의 강도를 구하기 위해서 색상 분포영상의 각 구간의 온도 및 높이의 특징을 적용하여 퍼지 소속 함수를 설계한 후, 소속 함수의 소속도를 구하고 퍼지 추론 규칙을 적용하여 풍향의 강도를 구한다.

• Korean Journal of Construction Engineering and Management
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• v.4 no.1 s.13
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• pp.81-89
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• 2003

This research suggests the FD-AHP decision making model for Construction Projects which is composed of two main method to prevent a ranking invert situation ; First, to make the consensus of the experts consistent, we utilize Fuzzy-Delphi method to adjust the fuzzy rating of every expert to achive the consensus condition with the fuzzy linguistic presentation. Second, to handle vague linguistic presentation caused by expert's experiences and subjective judgement, we propose Fuzzy-AHP which is able to enhance precision of construction projects decision mating situation. Moreover, with the correlation analysis, we show that the validity of the FD-AHP model under a decision making task specially on where highly demanded expert's experiences and intuition.

• 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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.10
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• pp.2201-2206
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• 2010

The shortage of fossil fuel drives researchers to find a new way to increases energy efficiency. In this paper, we propose a method to control the direction and speed of an air conditioner using a thermal image and fuzzy controlling method, which results in the increase of energy efficiency. The thermal image is first converted into a color temperature image which represents the temperature range from $24.0^{\circ}C$ to $27.0^{\circ}C$. The temperature image is divided into 5 columns and the distribution of them is used to analyze room temperature and control an air conditioner. The proposed method was applied to 300 by 400 thermal images. When the performance of the proposed method was compared to existing systems in energy efficiency, the proposed method was better than existing methods, which is clear from experimental results.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.2
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• pp.87-93
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• 2009

Intrusion tolerant system enables essential services to maintain for a period of time under system failure, malicious attacks and is gaining more importance in national defense, communication infrastructure, and financial sector. However, few objective evaluation criteria for companies and agencies to introduce an appropriate system are available. This paper proposes a suitability evaluation method, using Analytic hierarchy process and fuzzy integral, for intrusion tolerant system, along with evaluation criteria which considers the characteristics and costs of systems in addition to other factors.

• Journal of Digital Convergence
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• v.15 no.11
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• pp.425-432
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• 2017

The current recommendation systems have problems including the difficulty of figuring out whether they recommend items that actual users have preference for or have simple interest in, the scarcity of data to recommend proper items due to the extremely small number of users, and the cold-start issue of the dropping system performance to recommend items that can satisfy users according to the influx of new users. In an effort to solve these problems, this study implemented a movie recommendation system to ensure user satisfaction by using the Fuzzy-Analytic Hierarchy Process, which can reflect uncertain situations and problems, and the data partition algorithm to group similar items among the given ones. The data of a survey on movie preference with 61 users was applied to the system, and the results show that it solved the data scarcity problem based on the Fuzzy-AHP and recommended items fit for a user with the data partition algorithm even with the influx of new users. It is thought that research on the density-based clustering will be needed to filter out future noise data or outlier data.

• Journal of Navigation and Port Research
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• v.28 no.3
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• pp.177-184
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• 2004

The purpose of this study is to identify and evaluate the competitiveness of container ports in ASEAN(Association of Southeast Asian Nations) and Korea, which plays a leading role in basing the hub of international logistics strategies at the onset of the 21st century. Its ultimate purpose is to consider the relevant policy-making by comparing the competitiveness of ASEAN and Korea's container ports. This paper adopted the HFP method, which is an empirical analysis that evaluated the port competitiveness by quantifying it a, a qualitative attribute in the aforementioned area, where both ASEAN and Korea vie with each other for increasing container throughput. The results of this study showed that Singapore ranked the first in the subject of study in view of the competitiveness, followed by Busan(2) and Manila(2) as a leading group of the relevant ports in international logistics strategies. This analytic evaluation contributes to the empirical approach applied to policy-making by the HFP method, which is the newest research technique in social science through the comparative study of port competitiveness between ASEAN and Korea.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.5
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• pp.158-167
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• 2008

In recent years, various information technologies including ubiquitous computing technology have been developed and deployed. The more ubiquitous services based on ubiquitous technology have widely been spread, the more evaluation methods of those services are required. In this study, we suggest a framework for evaluating ubiquitous services by identifying evaluation factors and their relative importances. Combining review of related works and experts' opinions on the evaluation, we calculate the factors affecting ubiquitous service evaluation and relative importances among those factors using fuzzy Analytical Hierarchy Process (AHP). We conduct a case study to illustrate the applicability and feasibility of the suggested framework.