• Journal of Energy Engineering
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• v.4 no.2
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• pp.278-287
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• 1995

본 논문은 산업체의 열병합발전시스템이 각종 보조설비와 연계되어 운전되고 있을 경우의 최적운전 계획을 수립하였다. 최적운전계획을 수립하기 위하여 열병합발전시스템의 수리적 모델링은 물론 각종 보조설비들의 모델링도 수립하였으며, 사례연구를 통하여 모델링의 효용성을 검토하였다. 본 논문에서는 열병합발전시스템의 방식에서 버터밍사이클을 대상으로 삼았다. 시뮬레이션은 우선 선형계획법을 이용하여 운전계획을 수립한 후에 그 결과를 바탕으로 퍼지선형계획법을 적용하였으며, 퍼지화의 정도에 따라 여러 Case를 구성하여 단기운전계획을 수립하였다. 사례연구를 통해 각종 보조설비들이 버터밍사이클 방식에서 효과적으로 운전될 수 있음을 확인하였으며 퍼지선형계획법의 도입전후에서 얻은 운전계획 결과와의 상호 비교, 검토를 통하여 퍼지선형계획법을 도입시켰을 경우 수립된 운전계획의 효용성을 평가하였다.

• Journal of Korean Society of Forest Science
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• v.83 no.3
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• pp.271-279
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• 1994

This paper descbibes a fuzzy multiobjective linear programming, which is a relatively new approach in forestry in solving forest management problems. At first, the fuzzy set theory is explained briefly and the fuzzy linear programming(FLP) and the fuzzy multiobjective linear programming(FMLP) are introduced conceptionally. With the information obtained from the study area in Thailand, a standard linear programming problem is formulated, and optimal solutions (present net worth) are calculated for four groups of timber price by this LP model, respectively. This LP model is reformulated to a fuzzy multiobjective linear programming model to accommodate uncertain timber values and with this FMLP model a compromise solution is attained. Optimal solutions of four objective functions for four timber price groups and the compromise solution are compared and discussed.

• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.227-232
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• 2015

The fuzzy linear programming(FLP) is the useful approach to many real world problems under uncertainty. This paper deals with a FLP whose objective value is fuzzy. And the right hand sides of convergent equality constraints are fuzzy numbers. We assume that the membership function of the objective value is piecewise linear and those of the right hand side are trapezoidal. Each of these trapezoidal functions can be algebraically replaced with three linear functions. Then the FLP problem is transformed into the Zimmermann's symmetric model. The fuzzy solution based on the max-min rule can be obtained by solving the crisp linear programming problem derived from the symmetric model. A numerical example has illustrated our approach. The application of our approach to the inconsistent linear system can enable generate us to get define the useful and flexible inexact solutions within acceptable tolerance. Further research is required to generalize the membership function.

• Journal of Korean Society of Forest Science
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• v.99 no.6
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• pp.802-807
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• 2010

The objective of this study was to estimate potential of domestic long-term wood supply by using fuzzy linear programming (FLP). In order to construct a numerical formula model, maximization of total timber production was used for the objective function. Size limit of harvesting and sustained yield were used as the constraints. The results of comparison between LP and FLP were shown that LP is more suitable than FLP in terms of the amount of timber production and final forest stock. However, as long-term sustained yield was limitedly achieved by using LP, FLP was more desirable for prediction of potential wood supply. According to the results of this study, the potential of annual domestic wood supply was estimated about 10.5 million cubic meters. Gyeong buk, Jeon nam, Gangwon and Gyeong nam province were highly ranked in order of provincial potential of wood supply.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.8 no.1
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• pp.37-45
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• 1994

A method of optimal active and reactive power control for economic operation in electrical power system is presented in this paper. The major features and techniques of this paper are as follows: 1) The method presented for obtaining the equivalent active power balance equation applying the sparse Jacobian matrix of power flow equation instead of using B constant as active power Balance equation considering transmission loss, and for determining directly optimal active power allocation without repeating calculations. 2) More reasonable and economic profit by minimizing total fuel cost of thermal power plants instead of using transmission loss as objective function of reactive Power control can be achieved. 3) Particularly in reactive power control, computing time can be considerably reduced by using Fuzzy Linear Programming instead of using conventional Linear Programming.

• Journal of the Korean Institute of Intelligent Systems
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• v.2 no.3
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• pp.3-16
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• 1992

퍼지제어기는 입.출력 관점에서 일반적으로 입.출력에 대한 비선형 함수로 볼수 있다. 전문가의 제어 행위의 입.출력 관계가 크리시(crisp) 비선형 함수로 표현되었을때 그것을 언어적 퍼지 모델링(linguistic fuzzy modelling)하는 방법이 1-입력/ 1-출력 및 2-입력/1-출력의 static 시스템에 대하여 제안되었다. 이를 위해 소속함수 제한조건(membership function constraint)의 개념을 제시하고 선형계획법에 의한 최적화 기법을 이용하여 소속함수의 생성에 관한 체계적인 방법을 제안한다.

• Journal of Korean Society of Forest Science
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• v.85 no.2
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• pp.172-179
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• 1996

This paper described the application of fuzzy multiobjective linear programming to solving a multiple-use problem of forest resources management. At first the concepts of linear programming, fuzzy linear programming and fuzzy multiobjective linear programming were introduced briefly. In order to illustrate a role of fuzzy multiobjective linear programming in the process of multiple-use forest planning, the natural recreation forest in Mt. Yoomyung was selected for this study. A fuzzy multiobjective linear programming model is formulated with data obtained from this Mt. Yoomyumg natural recreation forest to solve the multiple-use management planning problem of forest resources. Finally, the results, which were obtained from the calculation of this model, were discussed. The maximal value of the membership function(${\lambda}$) was 0.29, when the timber production and the forest recreation function were optimized at the same time through the fuzzy multiobjective linear programming. The cutting area in each period was 102.7ha, while total cutting area was 410.8ha for 4 periods. During 4 periods $57,904m^3$ will be harvested from this natural recreation forest and at the same time total visitors were estimated to be about 8.6 millions persons.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.51-53
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• 2001

전력 수요 예측은 전력 수급 안정과 양질의 전력을 공급하기 위한 필수 기법이며 경쟁적인 전력시장에서 전력요금과 밀접한 관련이 있다. 그러므로, 경쟁적인 전력시장 구조하의 시장 참여자에게 있어서 전력 수요 예측은 매우 관심 있는 사항이다. 최근의 전력 수요 예측 기법으로 예측한 오차율을 살펴보면 평일과는 다르게 특수일의 전력 수요예측은 평균 5%를 상회하는 수준으로 예측의 정확도가 평일 예측에 비해 크게 낮은데 이유는 특수일이 평일에 비하여 부하의 크기가 다소 낮게 나타나고 특수일 마다 계절적인 차이가 있으며 각각의 특수일 마다 고유한 부하의 특성이 있으므로 과거 데이터를 이용할 때 동일 특수일을 이용하게 되며 따라서 평일과는 다르게 일년 단위로 과거 데이터 값들이 취득되므로 오차율이 커진다. 따라서 데이터들을 퍼지화하여 선형계획법을 수행하여 평균 $2{\sim}3%$ 정도의 우수한 결과를 도출한 바 있다. 본 논문에서는 퍼지 선형회귀분석법을 이용한 예측 기법에 최소자승법을 도입하여 특수일 전력 수요예측의 정확도를 개선하였다.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.9
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• pp.984-993
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• 1992

Fuzzy L.P. with Multi-criteria function is adopted in this VAR planning algorithm to accomplish the optimization of comflicting objectives, such as the amount of the VAR installed and power system loss, while keeping the bus voltage profile within an admissible range. Fuzzy L.P. with Multi-criteria function, a powerful tool dealing with the fuzziness of satisfaction levels of the constraints and the goal of objective functions, enables us to search for the solutions which may contribute in VAR planning. This advantage is not provided by traditional standardized L.P. The effectiveness of the proposed algorithm has been verified by the test on the IEEE-30 bus system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.12 no.20
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• pp.97-104
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• 1989

In this thesis, each objective functions with hierarchical system Bi-level linear programming (BLPP) Problem applications to fuzzy set theory conducted multiple objective programming problem. Using linear fuzzy membership functions make a change typical BLPP and presents modified method turn to account established BLPP method, presents operation results lead to example. Fuzzy Bi-level linear programming problem (FBLPP) can be natural describe realities of life then BLPP.