• Title/Summary/Keyword: simplex method

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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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    • 1998.06a
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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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상하분해 단체법에서 수정 Forrest-Tomlin 방법의 효율적인 구현

  • 김우제;임성묵;박순달
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1998.10a
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    • pp.63-66
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    • 1998
  • In the implementation of the simplex method program, the representation and the maintenance of basis matrix is very important, In the experimental study, we investigates Suhl's idea in the LU factorization and LU update of basis matrix. First, the triangularization of basis matrix is implemented and its efficiency is shown. Second, various technique in the dynamic Markowitz's ordering and threshold pivoting are presented. Third, modified Forrest-Tomlin LU update method exploiting sparsity is presented. Fourth, as a storage scheme of LU factors, Gustavson data structure is explained. Fifth, efficient timing of reinversion is developed. Finally, we show that modified Forrest-Tomlin method with Gustavson data structure is superior more than 30% to the Reid method with linked list data structure.

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A study on the column subtraction method applied to ship scheduling problem

  • Hwang, Hee-Su;Lee, Hee-Yong;Kim, Si-Hwa
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2004.04a
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    • pp.401-405
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    • 2004
  • Column subtraction, originally proposed by Harche and Thompson(]994), is an exact method for solving large set covering, packing and partitioning problems. Since the constraint set of ship scheduling problem(SSP) have a special structure, most instances of SSP can be solved by LP relaxation. This paper aims at applying the column subtraction method to solve SSP which can not be solved by LP relaxation. For remained instances of unsolvable ones, we subtract columns from the finale simplex table to get another integer solution in an iterative manner. Computational results having up to 10,000 0-1 variables show better performance of the column subtraction method solving the remained instances of SSP than complex branch-and-bound algorithm by LINDO.

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Economic Dispatch based on Primal Interior Point Method (Primal Interior Point 법에 의한 경제급전)

  • Jung, Leen-Hark;Cho, Yang-Haeng;Park, Kyu-Hong
    • Proceedings of the KIEE Conference
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    • 2002.07a
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    • pp.366-368
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    • 2002
  • This paper presents a technique that can obtain an optimal solution for the Security-Constrained Economic Dispatch (SCED) problems using the Interior Point Method (IPM) while taking into account of the power flow constraints. The SCED equations are formulated by using only the real power flow equations from the optimal power flow. Then an algorithm is presented that can linearize the SCED equations based on the relationships among generation real power outputs, loads, and transmission losses to obtain the optimal solutions by applying the linear programming (LP) technique. Finally, the application of the Primal Interior Point Method (PIPM) for solving the optimization problem based on the proposed linearized objective function is presented. The results are compared with the Simplex Method and the Promising results ard obtained.

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A Study on the Strong Polynomial Time Algorithm for the Linear Programming (선형계획문제의 강성다항식 계산단계 기법에 관한 연구)

  • Chung, S.J.;Kang, W.M.;Chung, E.S.;Hu, H.S.
    • Journal of Korean Institute of Industrial Engineers
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    • v.19 no.4
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    • pp.3-11
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    • 1993
  • We propose a new dual simplex method using a primal interior point. The dropping variable is chosen by utilizing the primal feasible interior point. For a given dual feasible basis, its corresponding primal infeasible basic vector and the interior point are used for obtaining a decreasing primal feasible point The computation time of moving on interior point in our method takes much less than that od Karmarker-type interior methods. Since any polynomial time interior methods can be applied to our method we conjectured that a slight modification of our method can give a polynomial time complexity.

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A study on the column subtraction method applied to ship scheduling problem

  • Hwang, Hee-Su;Lee, Hee-Yong;Kim, Si-Hwa
    • Journal of Navigation and Port Research
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    • v.28 no.2
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    • pp.129-133
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    • 2004
  • Column subtraction, originally proposed by Harche and Thompson(1994), is an exact method for solving large set covering, packing and partitioning problems. Since the constraint set of ship scheduling problem(SSP) have a special structure, most instances of SSP can be solved by LP relaxation This paper aim, at applying the column subtraction method to solve SSP which am not be solved by LP relaxation For remained instances of unsolvable ones, we subtract columns from the finale simplex table to get another integer solution in an iterative manner. Computational results having up to 10,000 0-1 variables show better performance of the column subtraction method solving the remained instances of SSP than complex branch and-bound algorithm by LINDO.

Detection and Differentiation of Herpes Simplex Virus 1 and 2, and Varicella-Zoster Virus in Vesicle Fluid, Joint Fluid and Serum using PCR Method (중합효소 연쇄반응에 의한 수포액, 혈액과 관절액에서 단순포진 바이러스 1, 2와 대상포진 바이러스의 검출과 감별)

  • Park, Hae-Kyung;Woo, So-Youn;Kim, Hyun-Jin;Lee, Chung-Hwa
    • The Journal of the Korean Society for Microbiology
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    • v.35 no.2
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    • pp.191-201
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    • 2000
  • The viruses of Herpes Simplex Virus 1 (HSV-1), Herpes Simplex Virus 2 (HSV-2) and Varicella-Zoster virus (VZV) which belong to the alpha herpes subfamily are important human pathogens. When eruptions were not fully developed from these viral infections, clinical diagnosis was not always easy and required virological confirmation test. The above viruses were reactivated in individuals who were compromised in immune competence for one reason or another. Polymerase chain reaction (PCR) enables rapid and sensitive detection of HSV and VZV DNAs. Its sensitivity was largely influenced by choice of primers. Authors conducted a study to detect of those three viruses in human specimens including vesicle fluid and joint fluid and serum using PCR methods. Primers used for this study were the general primer pair GPHV-RU which was known to amplify within the genes enjoying the highest degree of homology between UL15 of HSV and UL42 of VZV. PCR with primers hybridized pair GPHV-RU amplifies a 396 bp with THP-1 and HSV-2 standard strain DNA and 405 bp with VZV standard strain DNA. Restriction enzyme cleavage with HpaII and DdeI were used to detect and distinguish DNAs of THP-1 and HSV-2 and VZV. The purpose of this study was a rapid and easy detection of VZV and THP-1 or HSV-2 from various clinical specimens (vesicle fluid, serum and joint fluid) by PCR method. Used methods were: HSV PCR with primer 1, 2 and HpaII RE digestion; VZV nested PCR; HSV PCR with primer A, Band BssHII RE digestion. 1) In 33 cases (33/42, 78.6%) VZV was detected single or mixed infection from 42 clinical specimens which included vesicle fluid (5), serum form respiratory infected children (10), serum from immune suppressed adult cancer patients (7) and joint fluid from arthritis patients (20). 2) In 20 cases (20/42, 47.6%) HSV was detected singly or mixed infection and 19 of those cases were HSV-2 and 1 case was THP-1. 3) In 19 cases (19/42, 45.2%) VZV was singly detected which included serum from respiratory infected children (6 cases), joint fluid from arthritis patients (9 cases), vesicle fluid (2 cases) and serum form immunosuppressed cancer patients (2 cases). 4) HSV was singly detected in 6 cases (6/42, 14.3%) which included joint fluid from arthritis patients (5 cases) and serum form respiratory infected children (1 cases). 5) 14 cases of VZV and HSV mixed infection (14/42, 33.3%) were detected. They included vesicle fluid (3 cases), serum form immunosuppressed cancer patients (4 cases), serum from respiratory infected children (2 cases) and joint fluid from arthritis patients (5 cases). 6) HSV-1 and HSV-2 detection and typing by HSV PCR with primer A, Band BssHII RE digestion method was more sensitive and the results were easier to detect than on other method.

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Optimal Algorithm for Transshipment Problem (중개수송 문제 최적 알고리즘)

  • Lee, Sang-Un;Choi, Myeong-Bok
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.13 no.1
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    • pp.153-162
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    • 2013
  • This paper proposes the most simple method for optimal solution of the transshipment problem. Usually the transshipment problem is solved by direct linear programming or TSM (Transportation Simplex Method). The method using TSM has two steps. First it is to get a initial solution using NCM, LCM, or VAM, second to refine the initial solution using MOD or SSM. However the steps is complex and difficult. The proposed method applies the method that transforms transshipment problem to transportation problem. In the proposed method it simply selects the minimum cost of rows about transportation problem, and then it applies the method that assigns a transported volume as an ascending sort of the costs of rows about the selected costs. Our method makes to be very fast got the initial value. Also we uses the method that controls assignment volume, if a heavy item of cost is assigned to a transported volume and it has a condition to be able to transform to more lower cost. The proposed algorithm simply got the optimal solution with applying to 11 transshipment problem.

A matrix displacement formulation for minimum weight design of frames

  • Orakdogen, Engin
    • Structural Engineering and Mechanics
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    • v.14 no.4
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    • pp.473-489
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    • 2002
  • A static linear programming formulation for minimum weight design of frames that is based on a matrix displacement method is presented in this paper. According to elementary theory of plasticity, minimum weight design of frames can be carried out by using only the equilibrium equations, because the system is statically determinate when at an incipient collapse state. In the present formulation, a statically determinate released frame is defined by introducing hinges into the real frame and the bending moments in yield constraints are expressed in terms of unit hinge rotations and the external loads respectively, by utilizing the matrix displacement method. Conventional Simplex algorithm with some modifications is utilized for the solution of linear programming problem. As the formulation is based on matrix displacement method, it may be easily adopted to the weight optimization of frames with displacement and deformation limitations. Four illustrative examples are also given for comparing the results to those obtained in previous studies.

A Neuro-Fuzzy Approach to Integration and Control of Industrial Processes:Part I

  • Kim, Sung-Shin
    • Journal of the Korean Institute of Intelligent Systems
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    • v.8 no.6
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    • pp.58-69
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    • 1998
  • This paper introduces a novel neuro-fuzzy system based on the polynomial fuzzy neural network(PFNN) architecture. The PFNN consists of a set of if-then rules with appropriate membership functions whose parameters are optimized via a hybrid genetic algorithm. A polynomial neural network is employed in the defuzzification scheme to improve output performance and to select appropriate rules. A performance criterion for model selection, based on the Group Method of DAta Handling is defined to overcome the overfitting problem in the modeling procedure. The hybrid genetic optimization method, which combines a genetic algorithm and the Simplex method, is developed to increase performance even if the length of a chromosome is reduced. A novel coding scheme is presented to describe fuzzy systems for a dynamic search rang in th GA. For a performance assessment of the PFNN inference system, three well-known problems are used for comparison with other methods. The results of these comparisons show that the PFNN inference system outperforms the other methods while it exhibits exceptional robustness characteristics.

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