• Title/Summary/Keyword: Column-Generation

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Automatic Generation of Structured Hyperdocuments from Multi-Column Document Images (복잡환 다단 문서 영상으로부터 구조화된 하이퍼문서의 자동 생성)

  • 이지연;강희중;이성환
    • Proceedings of the Korean Information Science Society Conference
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    • 1999.10b
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    • pp.458-460
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    • 1999
  • 본 논문에서는 다양한 객체를 포함한 다단 문서 영상을 원본 문서와 거의 유사한 형태의 HTML 문서로 변환할 수 있는 방법을 제안한다. 또한 논문이나 매뉴얼, 책의 한 단원 등 여러장의 입력 문서의 경우, 문서의 논리적인 구조 분석을 수행하고 장이나 절 등의 섹션 제목들을 계층화하여 다단 문서의 변환과 동시에 구조화된 목차 페이지도 함께 자동 생성하는 방법을 제안한다. 제안된 다단 문서 변환 알고리즘을 잡지, 신문, 광고지, 매뉴얼 등, 비정형화된 문서에 적용한 결과, 원본 문서의 형태와 구조에 큰 변함없이 유사하게 변환되었고, 논리적인 구조 분석 및 섹션 제목들의 계층화 작업 또한 정확히 수행되어 구조화된 목차 페이지의 자동 생성이 가능하였다.

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Finding Optimal Small Networks by Mathematical Programming Models (수리계획 모형을 이용한 최적의 작은 네트워크 찾기)

  • Choi, Byung-Joo;Lee, Hee-Sang
    • IE interfaces
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    • v.21 no.1
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    • pp.1-7
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    • 2008
  • In this paper we study the Minimum Edge Addition Problem(MEAP) to decrease the diameter of a graph. MEAP can be used for improving the serviceability of telecommunication networks with a minimum investment. MEAP is an NP-hard optimization problem. We present two mathematical programming models : One is a multi-commodity flow formulation and the other is a path partition formulation. We propose a branch-and-price algorithm to solve the path partition formulation to the optimality. We develop a polynomial time column generation sub-routine conserving the mathematical structure of a sub problem for the path partition formulation. Computational experiments show that the path partition formulation is better than the multi-commodity flow formulation. The branch-and-price algorithm can find the optimal solutions for the immediate size graphs within reasonable time.

Research and Anaysis of Wave Energy Characteristic for Wave Generation System

  • Oh Jin-Seok
    • Journal of Advanced Marine Engineering and Technology
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    • v.30 no.4
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    • pp.520-526
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    • 2006
  • Wave Energy is a derivative of the solar energy input to the earth, which is accumulated on open water surfaces by the action of the winds Waves are disturbances in the water surface. This paper is interested primarily in progressive waves, which carry energy from one place to another Waves are irregular in size and frequency. Moreover the surface of the sea is one of the most hostile environments for engineering structures and materials. The idea of harnessing the tremendous power of the ocean's waves is not new. Hundreds of wave energy conversion techniques have been suggested over the last two centuries. Although many WECS (Wave Energy Conversion Systems) have been invented, only a few systems have been tested and evaluated. This paper describes the characteristic of WES (Wave Energy System) in terms of, devices, resource and potential, etc.. Finally, this paper provides a summary of general and specific conclusions and recommendations concerning WECS potential in Korea.

A Branch-and-price Algorithm for the Minimum ADM Problem on WDM Ring Networks (WDM 링에서의 ADM 최소화 문제에 대한 분지평가 해법)

  • Chung, Ji-Bok
    • Journal of the Korean Operations Research and Management Science Society
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    • v.32 no.4
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    • pp.51-60
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    • 2007
  • In this study, we consider the minimum ADM problem which is the fundamental problem for the cost-effective design of SONET ADM embedded in WDM ring networks. To minimize the number of SONET ADMs, efficient algorithms for the routing and wavelength assignment are needed. We propose a mathematical model based on the graph theory for the problem and propose a branch-and-price approach to solve the suggested model effectively within reasonable time. By exploiting the mathematical structure of ring networks, we developed polynomial time algorithms for column generation subroutine at branch-and-bound tree. In a computer simulation study, the suggested approach can find the optimal solution for sufficient size networks and shows better performance than the greedy heuristic method.

An optimal algorithm for aircraft scheduling problem by column generation (열 생성 기법에 의한 항공기 운항계획문제의 최적해법)

  • 기재석;강맹규
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1993.04a
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    • pp.162-173
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    • 1993
  • 항공기 운항계획은 항공사의 계획업무 중 핵심적인 문제로 운항편수와 항공기 출발시간 그리고 운항할 항공기의 기종을 결정하는 문제이다. 본 연구에서는 이익을 최대로 하는 운항계획을 수립하기 위한 새로운 최적해법을 제안한다. 일반적으로 항공기 운항계획은 대규모의 정수 선형계획 문제이기 때문에 기존의 정수 최적해법으로 최적해를 계산하기가 쉽지 않다. 본 연구에서는 모든 결정변수를 사용하지 않고 필요에 따라 일부분의 결정변수만을 생성하여 선형 최적해를 계산하는 열 생성 최적해법을 제안한다. 이 해법을 이용하여 대규모 정수계획인 운항계획의 최적해를 매우 효율적으로 계산할 수 있는 해법을 제안한다. 실제 항공기 운항계획에 본 연구에서 제안하는 최적해법을 적용한 결과를 보여 그 효율성이 월등함을 보인다.

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Study on Vibration and Thermal Characteristics Applying Staking to CCGA Package for Space Applications (우주용 CCGA에서 Staking 적용에 따른 진동 및 열 특성 연구)

  • Jeong, Myung Deuk;Jung, Sunghoon;Hong, Young Min
    • Journal of the Korea Institute of Military Science and Technology
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    • v.23 no.6
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    • pp.574-581
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    • 2020
  • This paper describes the stacking effect for Ceramic Column Grid Array(CCGA) packages used for satellites. Reflow Soldering Process suitable for CCGA package with back structure was set as the process development goal to meet European Cooperation for Space Standardization(ECSS) standard. After analyzing the stacking effect according to the type of CCGA, it is verified by applying it to the CCGA Reflow Soldering Process. In order to confirm the validity of the staking effect analyzed in terms of vibration and thermal characteristics, it is verified through actual specimen production. It analyzes the cause of crack occurrence in the CCGA package and estimates the crack generation point using previously acquired inspection data.

A Study on the Optimal Routing Problem for a Transfer Crane (컨테이너 터미널에서의 트랜스퍼 크레인의 최적 운영 방안에 관한 연구)

  • Kim, Hu-Gan;Kim, Chul-Han
    • Journal of the Korean Operations Research and Management Science Society
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    • v.33 no.1
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    • pp.35-49
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    • 2008
  • To load a container in a yard block onto a ship, a Transfer Crane (TC) moves to a target yard bay, then its hoist picks up a selected container and loads it onto a waiting Yard Truck (YT). An optimal routing problem of Transfer Crane is a decision problem which determines a given TC's the visiting sequence of yard-bays and the number of containers to transfer from each yard-bay. The objective is to minimize the travel time of the TC between yard-bays and setup time for the TC in a visiting yard. In this paper, we shows that the problem is NP-complete, and suggests a new formulation for it. Using the new formulation for the problem, we investigate some characteristics of solutions, a lower and upper bounds for it. Moreover, our lower and upper bound is very efficient to applying some instances suggested in a previous work.

A Branch-and-Price Algorithm for the Bandwidth Packing Problem (대역폭 분할 문제를 위한 Branch-and-Price 알고리듬)

  • Kim Deokseong;Lee Kyungsik;Park Sungsoo
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2003.05a
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    • pp.381-385
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    • 2003
  • We consider the bandwidth parking problem arising from telecommunication networks The problem is to determine the set of calls to be routed and an assignment or them to the paths in arc capacitated network. The objective is to maximize profit. We formulate the problem as an integer programming and propose an algorithm to solve it. Column generation technique to solve the linear programming relxation is proposed with two types of columns in addition, to obtain an optimum integer solution, we consider a new branching strategy. Computational experiments show that the algorithm gives option at solutions within reasonably small time limits.

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Antioxidant Activity of Roasted Defatted Perilla Seed

  • Jung, Mee-Jung;Chung, Hae-Young;Choi, Jae-Sue
    • Natural Product Sciences
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    • v.7 no.3
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    • pp.72-75
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    • 2001
  • The antioxidant activity of roasted defatted perilla (Perilla frutescens) seed was determined by measuring its radical scavenging effect on 1,1-diphenyl-2- picrylhydrazyl (DPPH) radicals, inhibitory activity on total reactive oxygen species generation in kidney homogenates using 2',7'-dichlorodihydro-fluorescein diacetate, and scavenging effect on authentic peroxynitrites. The methanolic extract of roasted defatted perilla seed showed strong scavenging activity in both DPPH and peroxynitrite radicals, and thus fractionated with several solvents. The antioxidant activity potential of the individual fraction was in the order of ethyl acetate>n-butanol>dichloromethane>water>n-hexane fraction. The ethyl acetate soluble fraction exhibiting strong antioxidant activity was further purified by repeated silica gel and Sephadex LH-20 column chromatography. Luteolin was isolated as one of the active principles from the ethyl acetate fraction, together with the inactive chrysoeriol and apigenin.

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An Optimization Algorithm for the Maximum Lifetime Coverage Problems in Wireless Sensor Network

  • Ahn, Nam-Su;Park, Sung-Soo
    • Management Science and Financial Engineering
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    • v.17 no.2
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    • pp.39-62
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    • 2011
  • In wireless sensor network, since each sensor is equipped with a limited power, efficient use of the energy is important. One possible network management scheme is to cluster the sensors into several sets, so that the sensors in each of the sets can completely perform the monitoring task. Then the sensors in one set become active to perform the monitoring task and the rest of the sensors switch to a sleep state to save energy. Therefore, we rotate the roles of the active set among the sensors to maximize the network lifetime. In this paper, we suggest an optimal algorithm for the maximum lifetime coverage problem which maximizes the network lifetime. For comparison, we implemented both the heuristic proposed earlier and our algorithm, and executed computational experiments. Our algorithm outperformed the heuristic concerning the obtained network lifetimes, and it found the solutions in a reasonable amount of time.