• 품질경영학회지
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• 제11권1호
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• pp.2-9
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• 1983

For the optimal achievement of system goals through a systematic analysis of the complex problems, systems engineering provides us the concepts and methodology that include comprehensive interpretability (or understandability), universal applicability, and feasibility. Under this aspect, the main objective of this study is that it introduces mathematical system theory (MST) as the fundamental tool of SE into the Inventory Control among the related parts with IE, and review it's applicability. Through its work, we can find that it has the alternative aspects with which it can replace other existing methods for problem-solving in understanding and analyzing structurally systems in themselves as well as being considerable of the time evolutionary process of a given system.

• 대한산업공학회지
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• 제2권1호
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• pp.93-100
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• 1976

Given a fixed production process and facility capacity, the ability to respond to market fluctuations in terms of changes in production, work force, and inventory is the major task of production management. The costs involved are primarily payroll (regular and overtime), inventory carrying, and hiring and firing. The magnitude of these costs is usually a significant portion of the operating costs of the firm and consequently a small percentage saving due to astute aggregate scheduling can mean substantial absolute saving. At least three demonstrably optimal techniques have been developed for solving this aggregate scheduling problem. These three optimal are apparently LDR, PPP, and SDR. By combining these three different approaches, another optimal solution was obtained by me. I call this CDR (Combined Decision Rule). This approach appears to be useful. This approach may be generalizable to aggregate scheduling involving a short term resources.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2002년도 춘계공동학술대회
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• pp.378-384
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• 2002

In this paper, we propose a mixed integer optimization approach for solving the inventory problem with variable lead time, reorder point, crashing cost and price -quantity discount. Chang and Chang[15] study a continuous review inventory model in which lead time is a decision variable under price-quantity discount. However, their study cannot find the optimal solution due to the flaws in the modeling and the solution procedure. We present a complete procedure to find the optimal solution for the model. In addition to the above contribution, we also apply the minimax distribution free approach to the model to devise a practical procedure which can be used without specific information on demand distribution.

• 한국시스템다이내믹스연구
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• 제12권4호
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• pp.63-92
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• 2011

The purpose of this paper is to investigate a possibility of applying multimethodological approach for solving a dilemma. The motivation of this attempt is that the two different approaches, the system dynamics and the theory of constraints, resemble each other in having mental models for describing the target system and using graphic tools for representing those mental models. After a brief discussion on the comparison of the two approaches, a combined method applying to the problem of dilemma is suggested. For an experimental example, the proposed approach is applied to the sales and finance conflict on an inventory issue. The study shows that the suggested approach is able to complement each other's drawbacks. Especially constructing a stock-and-flow model and implementing a computer simulation would be very useful for quantifying the system's behavior which is hardly tracked down when applying the theory of constraints alone.

• 경영과학
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• 제5권1호
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• pp.56-70
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• 1988

In this study, We reviewed the solution methods (for the heuristic and optimization method) for the single-item dynamic lot-sizing problem, and improved the efficiency (speed and optimality) of the conventional heuristic method by utilizing the inventory decomposition property. The iventory decomposition property decomposes the given original problem into several independent subproblems without violating the optimality conditions. Then we solve each decomposed subproblems by using the conventional heuristics such as LTC, LUC, Silver-Meal etc. For testing the efficiency of the proposed decomposition method, we adopted the data sets given in Kaimann, Berry and Silver-Meal. The computational results show that the suggested problem solving framework results in some promising effects on the computation time and the degree of optimality.

• Industrial Engineering and Management Systems
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• 제8권1호
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• pp.14-21
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• 2009

We formulate a mathematical model of remanufacturing system as multi-stage reverse Logistics Network Problem (mrLNP) with minimizing the total costs for reverse logistics shipping cost and inventory holding cost at disassembly centers and processing centers over finite planning horizons. For solving this problem, in the 1st and the 2nd stages, we propose a Genetic Algorithm (GA) with priority-based encoding method combined with a new crossover operator called as Weight Mapping Crossover (WMX). A heuristic approach is applied in the 3rd stage where parts are transported from some processing centers to one manufacturer. Computer simulations show the effectiveness and efficiency of our approach. In numerical experiments, the results of the proposed method are better than pnGA (Prufer number-based GA).

• 직업교육연구
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• 제30권4호
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• pp.143-159
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• 2011

본 연구에서는 중 고등학생들의 또래관계에 있어서 가장 기본적인 측면들을 평가할 수 있는 청소년용 또래관계검사를 개발하고 신뢰도와 타당도를 검증하는데 목적을 두었다. 본 연구는 예비문항 내용의 적절성 및 타당성을 검토하고 최종검사를 개발하기 위하여 부산시 소재 3개 중학교와 3개 고등학교 학생 600명(남 306명, 여 294명)을 대상으로 설문 조사를 실시하고, 이로부터 4개의 주요 요인을 추출하고 문항의 의미를 고려하여 최종 42문항, 5점 평정척도를 개발하였다. 이렇게 개발된 또래관계검사를 타당화하기 부산시 소재 2개 중학교와 2개 고등학교 학생 400명을 대상으로 설문조사를 실시하였다. 타당도 조사에서는 이미 개발되어 있는 2개의 또래관계 관련 척도들과의 상관분석을 실시하였다. 그 결과 또래관계검사 문항의 타당도가 비교적 높은 것으로 입증되었다. 이상을 요약하면 본 또래관계검사는 내적합치도, 신뢰도, 타당도 측면에서 신뢰롭고 타당하다고 할 수 있다. 그리고 청소년 또래관계의 가장 기본적인 측면들을 종합적으로 평가할 뿐만 아니라 예비규준을 제시하여 집단과의 비교가 가능하게 하여 청소년들의 또래관계의 현황을 파악하고 상담계획을 수립하는데 도움이 될 것이라고 생각된다.

• 한국산학기술학회논문지
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• 제18권2호
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• pp.540-548
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• 2017

본 연구는 예비유아교사의 성취동기와 사회문제해결력, 사회지능과 사회문제해결력 간의 관계를 분석하고 성취동기와 사회지능이 사회문제해결력에 미치는 영향력을 분석하는 데 목적을 두었다. 본 연구에서는 Y지역의 전문대 유아교육과에 재학 중인 193명의 예비유아교사를 대상으로 실시하였다. 본 연구에서는 송승희(2009)의 성취동기 측정도구, 한순미(2011)의 사회지능 측정도구, 허규(2001)의 사회문제해결력 측정도구를 활용하여 예비유아교사에게 설문조사를 실시하였다. 수집된 자료는 SPSS 21.0 프로그램을 사용하여 Pearson의 상관관계분석을 실시하고, 영향력을 살펴보기 위해 회귀분석을 실시하였다. 자료를 분석한 결과 첫째, 예비유아교사의 성취동기와 사회문제해결력 간의 관계는 정적 상관관계를 보였다. 또한 사회지능과 사회문제해결력 간의 관계도 정적 상관관계를 보였다. 둘째, 예비유아교사의 성취동기와 사회지능은 각각 사회문제해결력을 의미 있게 예측하는 변인으로 나타났다. 예비유아교사의 성취동기는 사회문제해결력 단계 중 수행확인 단계에서 그 영향력이 높게 나타났다. 또한 사회지능은 문제규정 단계에서 가장 높게 예측하였다. 이러한 결과를 토대로 예비유아교사의 사회문제해결력의 향상을 도모하기 위해 사회적 지원이 요구된다. 예비유아교사의 성취동기 및 사회지능과 관련된 교육 프로그램이 교사를 양성하는 교육과정에서 지원되어야 함을 시사한다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제16권4호
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• pp.225-237
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• 2016

In conventional transportation problem (TP), all the parameters are always certain. But, many of the real life situations in industry or organization, the parameters (supply, demand and cost) of the TP are not precise which are imprecise in nature in different factors like the market condition, variations in rates of diesel, traffic jams, weather in hilly areas, capacity of men and machine, long power cut, labourer's over time work, unexpected failures in machine, seasonal changes and many more. To counter these problems, depending on the nature of the parameters, the TP is classified into two categories namely type-2 and type-4 fuzzy transportation problems (FTPs) under uncertain environment and formulates the problem and utilizes the trapezoidal fuzzy number (TrFN) to solve the TP. The existing ranking procedure of Liou and Wang (1992) is used to transform the type-2 and type-4 FTPs into a crisp one so that the conventional method may be applied to solve the TP. Moreover, the solution procedure differs from TP to type-2 and type-4 FTPs in allocation step only. Therefore a simple and efficient method denoted by PSK (P. Senthil Kumar) method is proposed to obtain an optimal solution in terms of TrFNs. From this fuzzy solution, the decision maker (DM) can decide the level of acceptance for the transportation cost or profit. Thus, the major applications of fuzzy set theory are widely used in areas such as inventory control, communication network, aggregate planning, employment scheduling, and personnel assignment and so on.

• Industrial Engineering and Management Systems
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• 제13권4호
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• pp.369-382
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• 2014

This paper introduces a new multi-product multi-period multi-objective aggregate production planning problem. The proposed problem is modeled using multi-objective mixed-integer mathematical programming. Three objective functions, including minimizing total cost, maximizing customer services level, and maximizing the quality of end-product, are considered, simultaneously. Several constraints such as quantity of production, available time, work force levels, inventory levels, backordering levels, machine capacity, warehouse space and available budget are also considered. Some parameters of the proposed model are assumed to be qualitative and modeled using fuzzy sets. Then, a fuzzy goal programming approach is proposed to solve the model. The proposed approach is applied on a real-world industrial case study of a color and resin production company called Teiph-Saipa. The approach is coded using LINGO software. The efficacy and applicability of the proposed approach are illustrated in the case study. The results of proposed approach are compared with those of the existing experimental methods used in the company. The relative dominance of the proposed approach is revealed in comparison with the experimental method. Finally, a data dictionary, including the way of gathering data for running the model, is proposed in order to facilitate the re-implementation of the model for future development and case studies.