• Title/Summary/Keyword: Extreme Points

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An interactive face search procedure for multiple objective linear programming

  • Lee, Dong-Yeup
    • Korean Management Science Review
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    • v.10 no.2
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    • pp.11-26
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    • 1993
  • This paper presents a new interactive procedure for multiple objective linear programming problem (MOLP). In practical multiple objective linear programming applications, there is usually no need for the decision maker to consider solutions which are not efficient. Therefore, the interactive procedure presented here searches only among efficient solutions and terminates with a solution that is guaranteed to be efficient. It also can converge to nonextreme efficient final solutions rather than being restricted to only extreme efficient points of the feasible set. The procedure does not require sophisticated judgements or inputs from the decision maker. One of the most attractive features of the procedure however, is that the method allows the DM to examine the efficient faces it finds. As iteration goes, the DM can explore a wide variety of efficient faces rather than efficient faces confined to only certain subregion of the feasible set of problem MOLP since the efficient faces that the procedure finds need not be adjacent. This helps the DM explore the nature of the efficient set of problem MOLP and also helps the DM have confidence with a final solution. For these reasons, I feel that the procedure offer significant promise in solving multiple objective linear programs rapidly and in a satisfying manner to the DM.

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A Numerical Analysis for Light Weight and Strength Improvement of Wind Power System Nacelle Cover (풍력발전기용 나셀외장부의 경량화 및 강도향상에 관한 수치해석)

  • Kang, Ji-Woong;Kwon, Oh-Heon;Jeong, Woo-Yul
    • Journal of the Korean Society of Safety
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    • v.25 no.4
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    • pp.1-6
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    • 2010
  • Wind power system is composed by 3 major parts, rotor blade, nacelle and tower. Especially, the nacelle cover has an important role to prevent the component of nacelle and rotor from an extreme external circumstance. Therefore it is necessary to analyze and evaluate the stress distribution and deformation for them in the design level. There are two major points in nacelle cover analysis. The one is nacelle cover itself and the other is cover support structure. According to GL specification, this study shows the result that CFRP nacelle cover of wind turbine satisfies the strength and deformation through numerical analysis using the commercial finite element analysis program.

Behavior of cable-stayed bridges under dynamic subsidence of pylons

  • Raftoyiannis, I.G.;Michaltsos, G.T.;Konstantakopoulos, T.G.
    • Interaction and multiscale mechanics
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    • v.5 no.4
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    • pp.317-345
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    • 2012
  • Cable-stayed bridges are often used in modern bridge engineering for connecting two geographical points of long distance. A special load case to cable-stayed bridges is earthquake, which can produce horizontal as well as vertical movements on the pylons of the bridge. These movements may be transient in nature, i.e., only resulting in the transient vibration of the bridge, but causing no damage consequences. In some extreme cases, they may cause permanent subsidence on one or more pylons of the bridge. In this paper, the effect of pylons' subsidence on the dynamic deformations of the bridge and on the cables' strength is thoroughly studied. Conclusions useful to the design of cable-stayed bridges will be drawn from the numerical study.

Meteorological Data Integrity for Environmental Impact Assessment in Yongdam Catchment (용담댐시험유역 환경영향평가의 신뢰수준 향상을 위한 기상자료의 품질검정)

  • Lee, Khil-Ha
    • Journal of Environmental Science International
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    • v.29 no.10
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    • pp.981-988
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    • 2020
  • This study presents meteorological data integrity to improve environmental quality assessment in Yongdam catchment. The study examines both extreme ranges of meteorological data measurements and data reliability which include maximum and minimum temperature, relative humidity, dew point temperature, radiation, heat flux. There were some outliers and missing data from the measurements. In addition, the latent heat flux and sensible heat flux data were not reasonable and evapotranspiration data did not match at some points. The accuracy and consistency of data stored in a database for the study were secured from the data integrity. Users need to take caution when using meteorological data from the Yongdam catchment in the preparation of water resources planning, environmental impact assessment, and natural hazards analysis.

A Quantity Flexibility Contract Model for Optimal Purchase Decision (최적 구매량 결정을 위한 QF 계약 모형)

  • Kim Jong-Soo;Kim Tai-Young;Kang Woo-Seok
    • Journal of the Korean Operations Research and Management Science Society
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    • v.31 no.2
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    • pp.129-140
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    • 2006
  • Quantity Flexibility contract coordinates individually motivated supplier and buyer to the systemwide optimal outcome by effectively allocating the costs of market demand uncertainty. The main feature of the contract is to couple the buyer's commitment to purchase no less than a certain percentage below the forecast with the supplier's guarantee to deliver up to a certain percentage above. In this paper we refine the previous models by adding some realistic features including the upper and lower limits of the purchase. We also incorporate purchase and canceling costs in a cost function to reflect the real world contracting process more accurately. To obtain the solution of the model, we derive a condition for extreme points using the Leibniz's rule and construct an algorithm for finding the optimal solution of the model. Several examples illustrating the algorithm show that the approach is valid and efficient.

A Study on Improved Codeword Extraction for Decoder of Two Dimensional Barcode PDF417 (PDF417 이차원 바코드 디코더에서 코드워드 추출 알고리즘의 성능 개선에 관한 연구)

  • 정정구;한희일
    • Proceedings of the IEEK Conference
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    • 2002.06d
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    • pp.89-92
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    • 2002
  • In this paper we present a barcode reader to decode two-dimensional symbology PDF-417 and propose a novel method to extract the bar-space patterns directly from the gray-level barcode image, which employs the location and the distance between extreme points of each row of the barcode image. This algorithm proves to be very robust from the high convolution distortion environments such as defocussing and warping, even under badly illuminating condition. If the scanned barcode image is a result of the convolution of a Gaussian-shaped point spread function with a bi-level image, popular image segmentation methods such as image thresholding can not distinguish between very narrow bar-space patterns with a couple of pixels wide. The proposed algorithm shows improved performance over current barcode readers.

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The Clinical Observation of Anaphylaxis on Bee-Venom Acupuncture (봉약침요법으로 발생한 Anaphylaxis에 대한 임상보고)

  • Youn, Hyoun-Min
    • Journal of Acupuncture Research
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    • v.22 no.4
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    • pp.179-188
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    • 2005
  • Objectives : This study is designed to observe anaphylatic reaction In two patients, who visited Dong-Eui University Oriental Medicine Center for Bee-Venom Acupuncture. Methods : Anaphylaxis is a clinical syndrome cheracterized by the acute system reaction of multiple organ systems to an IgE-mediated immunologic mediator release in previously sensitized individuals. Anaphylatic reaction of two patients treated by Bee-Venom Acupuncture were observed in order to analysis the clinical form. Results & Conclusion : STZ One case of Anaphylatic reaction was expressed clinically hypotension drowsy mentality, dizziness muscle contraction and so on. The other case was expressed ulticaria, itching sensation, nausea and erythema. Especially ulticaria erythema are end points of increased vascular permeability and vasodilatation at the extreme of the clinical spectrum.

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A Study of Debates on and Enforcement of the National Basic Livelihood Act (국민기초생활보장법 제정의 쟁점과 운영방안에 관한 연구)

  • Moon, Jin-Young
    • Korean Journal of Social Welfare
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    • v.38
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    • pp.100-125
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    • 1999
  • As economic crisis has deepened mass unemployment and widespread destitution since the end of 1997, the Korean society is now underway of social disorganisation. It is thus widely accepted that National Basic Livelihood Programme, which reformed the existing public assistance programme, is urgently needed to relieve low-income families from extreme poverty. It is in this regard that this paper purports to review the debates on, and to suggest the feasible schemes for the National Basic Livelihood Programme. For this purpose, chapter two critically reviews government's comprehensive counter-measures against mass unemployment, and chapter three examines main points of the National Basic Livelihood Act. Chapter four compares "programme-centrad approach" and "basic living approach", and duly suggests feasible schemes for the National Basic Livelihood Programme.

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A linear program approach for optimizing a linear function over an efficient set (유효해집합 위에서의 최적화 문제를 위한 선형계획모델에 관한 연구)

  • Song, Jung-Hwan
    • Journal of Korean Institute of Industrial Engineers
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    • v.26 no.3
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    • pp.220-226
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    • 2000
  • The problem (P) of optimizing a linear function $d^Tx$ over the set of efficient points for a multiple objective linear program (M) is difficult because the efficient set is nonconvex. There are some interesting properties between the objective linear vector d and the matrix of multiple objectives C and those properties lead us to establish criteria to solve (P) with a linear program. In this paper we investigate a system of the linear equations $C^T{\alpha}$ = d and construct two linearly independent positive vectors u, v such that ${\alpha}$ = u - v. From those vectors u, v, solving an weighted sum linear program for finding an efficient extreme point for the (M) is a way of getting an optimal solution of the problem (P). Therefore the theorems presented in this paper provided us an easy way of solving nonconvex program (P) with a weighted sum linear program.

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Elements of Power Electronics and Its Roles as the Key Technology (전력전자의 요소기술 과 요소기술로서의 전력전자)

  • Rim, Geun-Hie
    • Proceedings of the KIEE Conference
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    • 2000.07b
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    • pp.1067.1-1067.4
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    • 2000
  • During the last three decades power electronics has gone through energetic technical evolution. The technical needs from wide area such as in industrial, commercial, consumer, aerospace and environmental applications have driven the environment favorably for the power electronics. In the future, two extreme technology-expansion trends are expected: one into low power, and the other into very high power. The former is based on the high frequency and the circuit miniature using VLSI circuit and surface mounting aiming for the system-on-chip (SOC) technology. The latter includes the application areas of power utility such as HVDC, FACTS and SVC and large science area of electrophsycal apparatus such as thermonuclear fusion, acclerators, and electric guns. This paper describes the technology status of some major elements which are available today and the key roles of the power electronics from view points of applications. The author would like to take this opportunity to raise discussions about the future technology development trend of power electronics in our country with the fellow power electronics engineers.