• Title/Summary/Keyword: Linear Programming Model

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A Linear Programming Model to the Score Adjustment among the CSAT Optional Subjects (대입수능 선택과목 점수조정을 위한 선형계획모형 개발 및 활용)

  • Nam, Bo-Woo
    • Korean Management Science Review
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    • v.28 no.1
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    • pp.141-158
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    • 2011
  • This study concerns with an applicability of the management science approach to the score adjustment among the College Scholastic Aptitude Test(CSAT) optional subjects. A linear programming model is developed to minimize the sum of score distortions between optional subjects. Based on the analysis of the 377,089 CSAT(2010) applicants' performances in social science test section, this study proposes a new approach for the score equating or linking method of the educational measurement theory. This study makes up for the weak points in the previous linear programming model. First, the model utilize the standard score which we can get. Second, the model includes a goal programming concept which minimizes the gap between the adjusting goal and the result of the adjustment. Third, the objective function of the linear programing is the weighted sum of the score distortion and the number of applicants. Fourth, the model is applied to the score adjustment problem for the whole 11 optional subjects of the social science test section. The suggested linear programming model is a generalization of the multi-tests linking problem. So, the approach is consistent with the measurement theory for the two tests and can be applied to the optional three or more tests which do not have a common anchor test or a common anchor group. The college admission decision with CSAT score can be improved by using the suggested linear programming model.

Optimal Cooling Operation of a Single Family House Model Equipped with Renewable Energy Facility by Linear Programming (신재생에너지 단독주택 모델 냉방운전의 선형계획법 기반 운전 최적화 연구)

  • Shin, Younggy;Kim, Eui-Jong;Lee, Kyoung-ho
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.12
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    • pp.638-644
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    • 2017
  • Optimal cooling operation algorithm was developed based on a simulation case of a single family house model equipped with renewable energy facility. EnergyPlus simulation results were used as virtual test data. The model contained three energy storage elements: thermal heat capacity of the living room, chilled water storage tank, and battery. Their charging and discharging schedules were optimized so that daily electricity bill became minimal. As an optimization tool, linear programming was considered because it was possible to obtain results in real time. For its adoption, EnergyPlus-based house model had to be linearly approximated. Results of this study revealed that dynamic cooling load of the living room could be approximated by a linear RC model. Scheduling based on the linear programming was then compared to that by a nonlinear optimization algorithm which was made using GenOpt developed by a national lab in USA. They showed quite similar performances. Therefore, linear programming can be a practical solution to optimal operation scheduling if linear dynamic models are tuned to simulate their real equivalents with reasonable accuracy.

A Linear Programming Model for Production Planning of Photovoltaic Materials (태양광 발전 소재 생산계획을 위한 선형계획 모형)

  • Lee, Seon-Jong;Lee, Hyun Cheol;Kim, Jaehee
    • Korean Management Science Review
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    • v.32 no.4
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    • pp.19-28
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    • 2015
  • This study presents a mathematical programming model to develop production planning in the manufacturing processes for photovoltaic silicon ingots and wafers. The model is formulated as a linear programming model that maximizes total growth margin, which is composed of production cost, inventory cost, shortage cost, and sales profit while considering the constraints associated with the production environments of photovoltaic materials. In order to demonstrate the utility of the model for production planning, we run operations for a planning horizon of a year for a case study. When the primary results of this mathematical programming are compared with the historical records, the model could have resulted in the considerable increase of the total growth margin by effectively reducing inventory cost if a decision maker had employed the model as a decision support system with perfect information for sales demand.

A New Approach for Forest Management Planning : Fuzzy Multiobjective Linear Programming (삼림경영계획(森林經營計劃)을 위한 새로운 접근법(接近法) : 퍼지 다목표선형계획법(多目標線型計劃法))

  • Woo, Jong Choon
    • 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.

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KTX Trainset Maintenance Routing and Allocation System for Korea High-Speed Rail (한국고속철도를 위한 차량운용 및 할당시스템)

  • Hong Soon-Hum;Kim Seongho
    • Journal of the Korean Society for Railway
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    • v.8 no.5
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    • pp.391-397
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    • 2005
  • In this paper we present a model for the maintenance routing construction and the trainset allocation (maintenance routing problem). The model solves the maintenance routing problem using column generation algorithm which was used to combine constraint programming and linear programming. Ilog-cplex was used to solve the linear programming model and Ilog-solver was used to solve the constraint programming model. The computational experience is also provided.

Duality in non-linear programming for limit analysis of not resisting tension bodies

  • Baratta, A.;Corbi, O.
    • Structural Engineering and Mechanics
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    • v.26 no.1
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    • pp.15-30
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    • 2007
  • In the paper, one focuses on the problem of duality in non-linear programming, applied to the solution of no-tension problems by means of Limit Analysis (LA) theorems for Not Resisting Tension (NRT) models. In details, one demonstrates that, starting from the application of the duality theory to the non-linear program defined by the static theorem approach for a discrete NRT model, this procedure results in the definition of a dual problem that has a significant physical meaning: the formulation of the kinematic theorem.

Evaluation of the Effective Storage of Existing Agricultural Reservoir (기존 농업용 저수지에서의 유효저수량의 평가)

  • Ahn, Tae-Jin;Cho, Dong-Ho;Lee, Sang-Ho;Choi, Gye-Woon;Yoon, Yong-Nam
    • Journal of Korea Water Resources Association
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    • v.37 no.5
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    • pp.353-361
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    • 2004
  • Effective storage in agricultural reservoir has been determined through the reservoir simulation operation based on the water budget analysis. Since each watershed has the native property for runoff, considering the runoff yielding from the basin is feasible to the determination of reservoir effective storage. In this study the stochastic linear programming model considering mainly runoff from watershed has been also formulated to analyze the effective storage of the exiting reservoir. The linear decision rule coupled with chance-constrained model in the linear programming model contributes to reduce the size of linear program model without considering the period of analysis. The Geum-Gang reservoir located in Ansung have been adopted to evaluate the effective storage. It has been shown that the effective storage based on the linear programming model is greater than that based on the water budget analysis. It has been also desired that once the effective storage is obtained through the linear programming model, operation of the reservoir should be performed to check the designed capacity.

FLEXIBLE OPTIMIZATION MODEL FOR LINEAR SCHEDULING PROBLEMS

  • Shu-Shun Liu;Chang-Jung Wang
    • International conference on construction engineering and project management
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    • 2005.10a
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    • pp.802-807
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    • 2005
  • For linear projects, it has long been known that resource utilization is important in improving work efficiency. However, most existing scheduling techniques cannot satisfy the need for solving such issues. This paper presents an optimization model for solving linear scheduling problems involving resource assignment tasks. The proposed model adopts constraint programming (CP) as the searching algorithm for model formulation, and the proposed model is designed to optimize project total cost. Additionally, the concept of outsourcing resources is introduced here to improve project performance.

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Seat Allocation Model for Single Flight-leg using Linear Approximation Technique (선형근사 기법을 이용한 단일비행구간의 좌석할당 모형)

  • Song, Yoon-Sook;Lee, Hwi-Young
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2008.10a
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    • pp.65-75
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    • 2008
  • Over the last three decades, there are many researches focusing on the practice and theory of RM in airlines. Most of them have dealt with a seat assignment problem for maximizing the total revenue. In this study, we focus on a seat assignment problem in airlines. The seat assignment problem can be modeled as a stochastic programming model which is difficulty to solve optimally. However, with some assumptions on the demand distribution functions and a linear approximation technique, we can transform the complex stochastic programming model to a Linear Programming model. Some computational experiments are performed to evaluate out model with randomly generated data. They show that our model has a good performance comparing to existing models, and can be considered as a basis for further studies on improving existing seat assignment models.

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Seat Allocation Model for Single Flight-leg using Linear Approximation Technique (선형근사 기법을 이용한 단일비행구간의 좌석할당 모형)

  • Song, Yoon-Sook;Lee, Hwi-Young;Yoon, Moon-Gil
    • Korean Management Science Review
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    • v.26 no.3
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    • pp.117-131
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    • 2009
  • Over the last three decades, there are many researches focusing on the practice and theory of RM in airlines. Most of them have dealt with a seat assignment problem for maximizing the total revenue. In this study, we focus on a seat assignment problem in airlines. The seat assignment problem can be modeled as a stochastic programming model which is difficulty to solve optimally. However, with some assumptions on the demand distribution functions and a linear approximation technique, we can transform the complex stochastic programming model to a Linear Programming model. Some computational experiments are performed to evaluate out model with randomly generated data. They show that our model has a good performance comparing to existing models, and can be considered as a basis for further studies on improving existing seat assignment models.