• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.557-559
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• 2005

This paper proposes a method for choosing the best composite power system expansion plan considering a contingency security criterion. The proposed method minimizes the investment budget fer constructing new transmission lines subject to contingency criterion. it models the power system expansion problem as an integer programming one. The method solves for the optimal strategy using a branch and bound method that utilizes a network flow approach and the maximum flow-minimum cut set theorem. Although the proposed method is applied to a simple sample study, the test results demonstrate that the proposed method is suitable for solving the power system expansion-planning problem subject to practical future uncertainties.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.288-292
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• 1987

The purpose of this paper is to develope the parallel computation algorithm that enables it to minimize the completion tine of computation execution of the entire subtasks, under the constraints of the series-parallel precedence relation in each subtask. The developed algorithm was applied to the control of a robot manipulator functioned by multi-CPU's and to obtain the minimum time schedule so that real time control may be achieved. The completion time of computation execution was minimized by applying "Variable" Branch and Bound algorithm which was developed In this paper in determining the optimum ordered schedule for each CPU.

• Journal of Korean Society for Quality Management
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• v.18 no.2
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• pp.93-99
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• 1990

This paper considers the selection of process plans for a flexible manufacturing machine. Most of the planning models for the automated manufacturing systems are based on the assumption that for each part there is only one process plan available. This paper considers that for each part a number of different process plans are available, each of which may require specific types of tools. If the requisite tools are not on the machine, one or more tool switches must occur before the process plan can be processed. This paper develops an optimal algorithm of branch and bound method for the selection of process plans to minimize the number of tool switches.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.2
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• pp.137-140
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• 2004

다중 프로세서 시스템이 개발됨에 따라, 새로운 일정계획문제, 하나의 작업이 하나이상의 기계에 의해 동시에 처리되어야 하는 문제가 대두되었다. 이 연구에서는 선행관계를 가진 이러한 다중 프로세서 일정계획문제에 대해 다루어 보았다. 이 연구의 목적은 makespan을 최소화하는 일정계획을 찾는 것이다. 일반적으로 Branch and Bound 기법을 이용하여 선행관계를 가진 다중 프로세서 일정계획문제의 최적해를 찾았는데, 해의 탐색시간이 너무 오래 걸린다는 단점이 있었다. 본 연구에서는 짧은 시간 내에 최적해와 가까운 근사해를 simulated annealing(SA)방법을 이용하여 구해보았다. SA의 성능을 측정하기 위하여, SA의 CPU 처리시간과 구한 근사해를 40개의 예제문제를 통하여 Kramer의 방법의 CPU 처리시간과 최적해와 비교해 보았다.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2004.11a
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• pp.287-295
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• 2004

컨테이너 터미널의 적하 작업은 사전에 계획된 순서대로 컨테이너를 장치장(yard)에서 하나씩 반출하여 선박에 선적하는 작업이다. 만일 현재 반출하고자 하는 컨테이너의 상단에 다른 컨테이너들이 장치되어 있다면, 부득이하게 위에 놓여 있는 컨테이너들을 다른 곳으로 옮겨야 하는 재취급(rehandling)이 발생하고 이로 인하여 반출 작업은 지연된다. 본 논문에서는 적하 계획이 수립되어 장치장의 한 베이(bay)내 컨테이너들의 반출 순서가 결정되었을 때, 반출 시작 시점까지 남는 유휴 시간을 활용하여 재취급이 발생하지 않도록 컨테이너들을 재정돈(이적, 리마샬링)하는 방안을 제안한다. 본 제안 방안은 분지 한계법(branch and bound)을 적용하여 컨테이너 이동 계획을 탐색하며, 생성된 해는 최소의 컨테이너 이동 횟수가 보장된다. 4 단 6 열과 5 단 9 열의 장치장 구조를 대상으로 실험한 결과 99% 이상의 상황에서 허용할 수 있는 시간 내에 계획을 수립할 수 있음을 확인하였다.

• Journal of Bio-Environment Control
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• v.19 no.2
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• pp.117-121
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• 2010

To investigate effects of binding treatments of branches (FMB, fruiting mother branch; PSB, secondary scaffold branch; SSB, primary scaffold branch) on enlargement and coloring of persimmon 'Fuyu' fruits in ripening period, the branches were bound by steel wire. For eight weeks after binding treatments, Hunter $a^*$ of fruit peel in FMB and SSB binding treatments was more increased than in the others. In fruit characteristics harvested at eight weeks after the binding treatments, the fruit weight was heavier in the binding treatments than in control, the first of those was in SSB binding. The fruit height was higher in SSB binding than in the others, but the fruit diameter was longer in FMB and SSB binding treatments. Solid soluble content was higher in FMB and PSB binding treatments. $Chroma^*$ of the fruit peel was higher in FMB and PSB binding treatments as Hunter $a^*$ and $b^*$ values were higher and lower in FMB and SSB binding treatments, respectively. Lycopene and $\beta$-carotene content in the fruit peel were higher significantly in PSB and SSB binding treatments, total chlorophyll content in all the binding treatments was lower than in control.

• The KIPS Transactions:PartB
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• v.16B no.5
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• pp.403-410
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• 2009

The two-dimensional bin packing problem(2D-BPP) has been known to be NP-hard, and it is difficult to solve the problem exactly. Many approximation methods, such as genetic algorithm, simulated annealing and tabu search etc, have been also proposed to gain better solutions. However, the existing approximation algorithms, such as branch-and-bound and tabu search, have shown the low efficiency and the long execution time due to a large of iterations. To solve these problems, we first define the fitness function to simplify and increase the utility of algorithm. The function decides whether an item is packed into a given area, and as an important information for a packing strategy, the number of subarea that can accommodate a given item is obtained from the variant of the fitness function. Then we present a heuristic algorithm BF for 2D bin packing, constructed by the fitness function and subarea. Finally, the effectiveness of the proposed algorithm will be expressed by the comparison experiments with the heuristic and the metaheuristic of the literatures. As comparing with existing heuristic algorithms and metaheuristic algorithms, it has been found that the packing rate of algorithm BP is the same as 97% as existing heuristic algorithms, FFF and FBS, or better than them. Also, it has been shown the same as 86% as tabu search algorithm or better.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.3
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• pp.140-148
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• 2009

Recent advances in communication and multimedia technologies make it possible to provide video-on-demand(VOD) services and people can access video servers over the Internet at any time using their electronic devices, such as PDA, mobile phone and digital TV. Each device has different processing capabilities, energy budgets, display sizes and network connectivities. To support such diverse devices, multiple versions of videos are needed to meet users' requests. In general cases, VOD servers cannot store all the versions of videos due to the storage limitation. When a device requests a stored version, the server can send the appropriate version immediately, but when the requested version is not stored, the server first converts some stored version to the requested version, and then sends it to the client. We call this conversion process transcoding. If transcoding occurs frequently in a VOD server, the CPU resource of the server becomes insufficient to response to clients. Thus, to admit as many requests as possible, we need to maximize the CPU availability. In this paper, we propose a new algorithm to select versions from those stored on disk using a branch and bound technique to maximize the CPU availability. We also explore the impact of these storage management policies on streaming to heterogeneous users.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.1
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• pp.97-104
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• 2016

Because of rapid growth of data size, the number of data storage has been increased. When using multiple data storages, a distribute file system is essential to insure the availability of data files. The power consumption is a major problem when using a distributed file system with many data storages. Previous works have aimed at reducing the energy consumption with efficient file block layout by changing some data servers into stand-by mode. The file block migration has not been seriously considered because migration causes large cost. But when we consider addition of a new data server or file, file block migration is needed. This paper formulates the minimization of data block migration as an ILP optimization problem and solves it using branch-and-bound method. Using this technique, we can maximize the number of stand-by data servers with the minimum number of file block movement. However, computation time of branch-and-bound method of an ILP optimization problem increases exponentially as the problem size grows. Therefore this paper also proposes a data block and data server grouping method to solve many small ILP problems.

• Journal of Korean Institute of Industrial Engineers
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• v.6 no.2
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• pp.21-29
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• 1980

This paper deals with the capital budgeting problem of a firm where investments are risky and interrelated. The established models might be classified into two categories; One is the chance-constrained programming model and the other is the expected utility maximization model. The former has a rather limited objective function and does not consider the risk in direct manner. The latter, on the other hand, might lead to a wrong decision because it uses an approximate value of expected utility. This paper attempts to extend the applicability of the chance-constrained programming model by modifying its objective function into a more general form. The capital budgeting problem is formulated as a nonlinear 0-1 integer programming problem first, and is formulated into a linear 0-1 integer programming problem for finding a lower-bound solution of the original problem. The optimal solution of the original problem is then obtained by branch & bound algorithm.