• Title, Summary, Keyword: Linear programming (LP)

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A connection method of LPSolve and Excel for network optimization problem (네트워크 최적화 문제의 해결을 위한 LPSolve와 엑셀의 연동 방안)

  • Kim, Hu-Gon
    • Journal of the Korea Industrial Information Systems Research
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    • v.15 no.5
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    • pp.187-196
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    • 2010
  • We present a link that allows Excel to call the functions in the lp_solve system. lp_solve is free software licensed under the GPL that solves linear and mixed integer linear programs of moderate size. Our link manages the interface between Excel and lp_solve. Excel has a built-in add-in named Solver that is capable of solving mixed integer programs, but only with fewer than 200 variables. This link allows Excel users to handle substantially larger problems at no extra cost. Futhermore, we introduce that a network drawing method in Excel using arc adjacency lists of a network.

Roles of Glucose and Acetate as Carbon Sources in L-Histidine Production with Brevibacterium flavum FERM1564 Revealed by Metabolic Flux Analysis

  • Shioya, Suteaki;Shimizu, Hiroshi;Shimizu, Nobuyuki
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.7 no.3
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    • pp.171-177
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    • 2002
  • The metabolic flux pattern for L-histidine production was analyzed when glucose and/or acetate were used as carbon sources. Total L-histidine production was enhanced when mixed substrate (glucose and acetate) was used, compared wish that when either glucose or acetate was used as the sole carbon source. Theoretical maximum carbon fluxes through the main pathways for L-histldine production, cell growth, and ATP consumption for cell maintenance were obtained by the linear programming (LP) method. By comparison of the theoretical maximum carbon fluxes tilth actual ones, it was found that a large amount of glucose was actually used for maintenance of cell viability. On the other hand, acetate was used for cell growth. After depletion of acetate in the mixed substrate culture, the flux for glucose to L-histldine synthesis was markedly enhanced. A strategy for effective L-histidine production using both carbon sources was proposed.

Optimal Congestion Management Based on Sensitivity in Power System with Wind Farms (민감도를 이용하여 풍력단지가 연계된 송전계통의 최적혼잡처리)

  • Choi, Soo-Hyun;Kim, Kyu-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.12
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    • pp.1965-1970
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    • 2016
  • This paper studies generator rescheduling technique for congestion management in power system with wind farms. The proposed technique is formulated to minimize the rescheduling cost of conventional and wind generators to alleviate congestion subject to operational line overloading. The generator rescheduling method has been used with incorporation of wind farms in the power system. The locations of wind farms are selected based upon power transfer distribution factor (PTDF). Because all generators in the system do not need to participate in congestion management, the rescheduling has been done by generator selection based on the proposed generator sensitivity factor (GSF). The selected generators have been rescheduled using linear programming(LP) optimization techniques to alleviate transmission congestion. The effectiveness of the proposed methodology has been analyzed on IEEE 14-bus systems.

Postsolving in interior-point methods (내부점 선형계획법에서의 사후처리)

  • 이상욱;임성묵;성명기;박순달
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • pp.89-92
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    • 2003
  • It is often that a large-scale linear programming(LP) problem may contain many constraints which are redundant or cause infeasibility on account of inefficient formulation or some errors in data input. Presolving or preprocessing is a series of operations which removes the underlying redundancy or detects infeasibility in the given LP problem. It is essential for the speedup of an LP system solving large-scale problems to implement presolving techniques. For the recovery of an optimal solution for the original problem from an optimal solution for the presolved problem, a special procedure, so called postsolving, must be applied. In this paper, we present how a postsolving procedure is constructed and implemented in LPABO, a interior-point based LP system. Briefly, all presolving processes are logged in a data structure in LPABO, and after the end of the solution method an optimal solution for the original problem is obtained by tracing the logs. In each stage of the postsolving procedure, the optimality of intermediate solutions is maintained. We tested our postsolving procedure on Netlib, Gondzio and Kennington LP data sets, and concluded that the computational burden of the procedure is relatively negligible compared with the total solving time.

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An Achievement rate Approach to Linear Programming Problems with Convex Polyhedral Objective Coefficients

  • Inuiguchi, Masahiro;Tanino, Tetsuzo
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • pp.501-505
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    • 1998
  • In this paper, an LP problem with convex polyhedral objective coefficients is treated. In the problem, the interactivities of the uncertain objective coefficients are represented by a bounded convex polyhedron (a convex polytope). We develop a computation algorithm of a maxmin achievement rate solution. To solve the problem, first, we introduce the relaxation procedure. In the algorithm, a sub-problem, a bilevel programing problem, should be solved. To solve the sub-problem, we develop a solution method based on a branch and bound method. As a result, it is shown that the problem can be solved by the repetitional use of the simplex method.

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Determination of Optimal Hourly Water Intake Amount for H Arisu Purification Center using Linear Programming (선형계획법을 이용한 H 아리수 정수 센터 최적 취수량 결정)

  • Lee, Chulsoo;Lee, Kangwon
    • Journal of Korea Water Resources Association
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    • v.48 no.12
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    • pp.1051-1064
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    • 2015
  • Currently, the H purification plant determines the hourly water intake amount based on operator experience and skill. Therefore, inevitably, there are deviations among operators. While meeting time-varying demand and maintaining the proper water level in the clean water reservoir, the methodology for minimizing electricity cost, when dealing with different electricity rate time zones, is a very complicated problem, which is beyond an operator's capability. To solve this problem, a linear programming (LP) model is proposed, which can determine the optimal hourly water intake amount for minimizing the daily electricity cost. It is shown that an inaccurate estimate for the hourly water usage in the demand areas causes the water level constraint to be violated, which is the weak point of the proposed LP method. However, several examples with real-field data show that we can practically and safely solve this problem with safety margins. It is also shown that the safety margin method still works effectively whether the estimate is accurate or not. The operators need not attend the site at all times under the proposed LP method, and we can additionally expect reductions in labor costs.

A Study on the Introduction of Linear Programming Model into the Management of Korean Coastal and Offshore Fisheries (한국 연근해어업의 합리적 관리를 위한 LP모형의 도입방안에 관한 연구)

  • 박장일
    • The Journal of Fisheries Business Administration
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    • v.25 no.1
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    • pp.37-59
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    • 1994
  • Many studies to cope with the present problems of Korean coastal and offshore fisheries has been performed, but these were done partly in necessities and general studies for Korean inshore and offshore fisheries are in early stage. Most of these studies adopted analytical way of approach for each fishery individually and they could not reflect the effect of correlated interaction among fisheries on the several common species/stocks, and thus optimal effort allocation was impossible. To consider general fisheries and optimal effort allocation among competing mixed species, a linear programming (LP) approach is applied in this study and introduced into 16 important inshore and offshore fisheries with 13 constraining species which were chosen by annual yield order. This study is not based on the biological interaction among species (i.e., prey - predator system) but the technological interaction between species and fishing efforts. For the application of LP model in these fisheries, the standardization of fishing efforts through different fishing gears could not be successful and a new way of effort standardization through CPUE for vessel tonnage was originated. Total standardized fishing effort on a particular species i, Ei, is computed as the linear summation of standardized fishing effort generated by each fishery j. That is, (equation omitted) where $f_{j}$ is the total vessel tonnage of fishery j and aij is the coefficients contributing to the standardized fishing effort per ton for species i taken in fishery j. The total fishing effort level on species i due to both directed fishing and by - catch can thus be accounted in the aij's. Optimal effort allocation among the j fisheries may be considered a minimizing problem (minimize $\Sigma$ $f_{j}$), subject to the constraints that standardized fishing effort levels on particular species are maintained at, above, and below certain predefined levels. Fishing effort goals for individual species can be based on various biological and/or economic criteria, i.e., fishing effort level generating maximum sustainable yield and/or maximum economic yield. But in this study the $F_{0.1}$ criteria which was accepted as an approximate level for $F_{mey}$ by Outland and Boerema's (1973) study. The findings of this study are, (1) LP model can be applied to the Korean inshore and offshore fisheries giobally. (2) Through a new way of combining multiple different fisheries' efforts for a particular species together generating standardized fishing effort, Schaefer curve could be applied to the complex system successfully. (3) The results of this study for total reduction scale were mostly the same as those of prior studies, but different much from the individual scales of reduction. This study showed the necessities for exploitation of more concrete parameters to put into consideration of profitability of fisheries and social factors, and this model can be modified according to the actual constraints. Also, considering the age structure of stocks, this model can be developed into better one for better fisheries management.ent.

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A Study on Developing An Experimental Model to Solve for Optimal Forest-Level Timber Harvesting Schedules Using Linear Programming (대단지(大團地) 산림(山林)의 목재생산계획(木材生産計劃) 분석(分析)을 위한 선형계획(線型計劃) 실험전산모델에 관한 연구(硏究))

  • Chung, Joo Sang;Park, Eun Sik
    • Journal of Korean Society of Forest Science
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    • v.82 no.3
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    • pp.292-304
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    • 1993
  • This research developed a forest-level harvest scheduling model using linear programming (LP). The formulations of the LP model include timber production schemes with constraints of nondecling yield forest conversion strategies, the minimum timber supply, levels and the maximum cut acrages. The model is able to generate both Model I and Model II types of input matrix in MPS format. In this paper, use of LP in building the framework of the strategic forest planning model was justified by comparing the algorithmic characteristics of LP with those of Gentan probability and binary search approaches through literature reviews. In order to demonstrate the field applicability of the model proposed. (1) the harvest scheduling problem for about 11,000-hectare case study area (Mt. Baekun area in Southern Experimental Forest of Seoul National University) was formulated and soloed and (2) the effects of the change in task regulatory timber production constraints or. optimal harvesting schedules here investigated.

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A Model of Quality Function Deployment with Cost-Quality Tradeoffs (품질과 비용의 득실관계를 고려한 품질기능전개 모형)

  • 우태희;박재현
    • Journal of the Korea Safety Management and Science
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    • v.4 no.2
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    • pp.169-178
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    • 2002
  • This paper presents an analytic method of quality function deployment(QFD) that is to maximize customer satisfaction subject to technical and economic sides in process design. We have used Wasserman's normalization method and the analytical hierarchy process(AHP) to determine the intensity of the relationship between customer requirements and process design attributes. This paper also shows cost-quality model the tradeoff between quality and cost as a linear programming(LP) with new constraints that have designated special process required allocating firstly. The cost-quality function deployment of piston ring is presented to illustrate the feasibility of such techniques.

LP 모형에 의한 한국 정보산업기술의 R&D 투자규모 결정사례

  • 백관호;이규헌
    • Journal of Technology Innovation
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    • v.4 no.1
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    • pp.27-47
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    • 1996
  • The information technology, such as computer, telecommunication, semi- conductor and software technology, is very crucial to enhance the overall level of industrial technology. The workability of linear programming to decide the R&D investment of information technology has been tested in this paper. The case study of Korea during the year 1995 - 2004 suggests that we should enlarge the total investment volume especially on the software technology.

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