• Earthquakes and Structures
• /
• 제23권5호
• /
• pp.419-430
• /
• 2022

The metallic energy dissipation device (EDD) has been widely accepted as a useful tool for passive control of buildings against earthquakes. The distribution of metallic EDDs in a multi-story building may have significant influence on its seismic performance, which can be greatly enhanced if the distribution scheme is properly designed. This paper addresses the optimal distribution problem in the aim of achieving a desired level of performance using the minimum number of metallic EDDs. Five local search heuristic algorithms are proposed to solve the problem. Four base structures are presented as numerical examples to verify the proposed algorithms. It is indicated that the performance of different algorithms may vary when applied in different situations. Based on the results of the numerical verification, the recommended guidelines are finally proposed for choosing the appropriate algorithm in different occasions.

• 대한산업공학회지
• /
• 제35권1호
• /
• pp.92-100
• /
• 2009

Today international trade through maritime transportation is significantly increasing. Due to this increase, shipping companies are faced with problems concerning the repositioning of empty containers from import dominant ports. The liner shipping service network has been provided to transport containers which load customers' freights. Container ships are moved on the liner shipping service network by observing the predetermined route and transportation time. This research deals with the empty containers distribution problem considering the container ship route. A mathematical model based on the mixed integer program has been introduced in this study. The objective is to minimize the total relevant costs of empty containers such as handling, leasing, and inventory holding, etc. Due to the complexity of the problem, a genetic algorithm has been suggested to solve large sized problems within a reasonable time. Numerical experiments have been conducted to show the efficiency of the genetic algorithm.

• 산업공학
• /
• 제24권4호
• /
• pp.341-350
• /
• 2011

This paper considers a problem of locating both distribution centers and retailers in a zone-dependent two-level distribution network where either a distribution center or a retailer should be located in each zone. Customer demands of each zone should be satisfied directly from either its own distribution center or its own retailer being supplied from a distribution center of another zone. The objective of the proposed problem is to minimize total cost being composed of distribution center/retailer setup costs and transportation costs. In the analysis, the problem is proved to be NP-hard, so that a branch-and-bound algorithm is derived for the problem. Numerical experiments show that the proposed branch-and-bound algorithm provides the optimal solution efficiently for some small problems.

• 한국철도학회논문집
• /
• 제19권6호
• /
• pp.833-843
• /
• 2016

최근 철도 화물 수송은 컨테이너 전세 열차뿐만 아니라 시멘트, 철강 등 일반 화물의 전용열차 수가 증가하고 있고, 이에 따라 영차 수송 계획은 점차 단순해지고 있다. 반면에 공화차 수송의 경우, 수송 계획 최적화 시스템의 부재로, 사령의 경험에 의해 공화차 배분이 이루어지고 있으며, 이의 효율성 여부는 검증된 바 없고, 공화차 배분을 위한 별도의 의사결정지원시스템의 필요성은 여전히 존재한다. 본 연구에서는 연구 문헌상의 공화차 배분 최적화 모형뿐만 아니라 2010년 전후로 개발 되었다가 최근 사용이 중단된 화물수송최적화 시스템(KTOCS)상의 공화차 배분 최적화 모형을 비판적으로 살펴본 후, 수송 문제를 활용한 새로운 공화차 배분 최적화 모형 및 해법을 제시한다. 이 최적화 모형은 기존 모형과 달리, 추가 제약이 있는 수송문제에 포함되는 아크를 동적으로 생성해내는 열생성 기법에 기초하고 있다. 이를 이용한 우리나라 전체 철도 네트워크에 대한 시뮬레이션 결과, 실적 상에 나타난 공화차 km를 상당히 낮출 수 있는 것을 확인할 수 있었다.

• 산업경영시스템학회지
• /
• 제31권2호
• /
• pp.19-27
• /
• 2008

This paper addresses determining the location of the distribution centers in a discrete dynamic distribution system. In discrete and finite time horizon, the demands of retailers are dynamic for the periods. Some locations among the retailers can be chosen for the role of the distribution centers at the beginning of each period. The distribution centers have to be located at the location of minimizing logistics cost. Logistics cost factors are the operation cost and the fixed cost of distribution center, and the transportation cost. The distribution centers of minimizing sum of operation cost, fixed cost and transportation cost are determined among retailers in each period for the planning period. A mathematical model was formulated and a dynamic programming based algorithm was developed. A numerical example was shown to explain our problem.

• Structural Engineering and Mechanics
• /
• 제65권4호
• /
• pp.389-400
• /
• 2018

An exact solution for the title problem was obtained in closed-form fashion considering general boundary conditions. The expressions of moment, shear and shear coefficient (or shear factor) of cross section under the effect of arbitrary temperature distribution were first derived. In view of these relationships, the differential equations of Timoshenko beam under the effect of temperature were obtained and solved. Second, the characteristic equations of Timoshenko beam carrying several spring-mass systems under the effect of temperature were derived based on the continuity and force equilibrium conditions at attaching points. Then, the correctness of proposed method was demonstrated by a Timoshenko laboratory beam and several finite element models. Finally, the influence law of different temperature distribution modes and parameters of spring-mass system on the modal characteristics of Timoshenko beam had been studied, respectively.

• 산업경영시스템학회지
• /
• 제20권44호
• /
• pp.33-46
• /
• 1997

The location decision problem for distribution center is one of the most important problem in business logistics system. Because the proportion of holding and transportation cost to physical distribution cost in our country exceed the 60%, a corporation must feel strong pressure to investigate the location problem for distribution center. This paper presents an algorithm for determining the best location of distribution center in consideration with physical distribution cost, demand, and customer location. The methods of determining the distribution center location is that firstly many of proposed sites are built up where demand position is distributed, and then optimal location of distribution center is selected.

• 한국인터넷방송통신학회논문지
• /
• 제12권2호
• /
• pp.135-143
• /
• 2012

요본 논문은 혈액의 총 배송비용 최소화와 배송 허용시간 $T^*$ 조건을 만족시키는 최적의 물류센터 위치를 결정하는 알고리즘을 제안하였다. Zhang과 Yang은 각 지역에서 최대 거리에 위치한 2개 지점의 평균값이 배송제약시간보다 작은 지점의 위치를 이동시키는 방법을 제안하였으나 최단거리 계산 오류로 인해 물류센터 위치를 잘못 선정하였다. 제안된 알고리즘은 지역 간 최단거리 $l_{ij}$를 구하여 $_{max}l_{ij}{\leq}L^*$인 지점과 $l_{ij}>L^*$인 경로 $P_{ij}=v_i,v_k,{\cdots},v_l,v_j$에 대해 ($v_i,v_k$)와 ($v_j,v_l$)로 $l_{ij}-L^*$ 위치를 이동시킨 지점들 중에서 $_{max}l_{ij}{\leq}L^*$인 지점들을 최종 후보 물류센터 위치로 결정하였다. 이들 후보 지점들 중 총 배송비용이 최소가 되는 지점을 최적의 물류센터 지점으로 결정하였다.

• 한국항해학회지
• /
• 제23권4호
• /
• pp.63-76
• /
• 1999

This paper aims at developing an integrated fleet management support system for industrial carriers who usually control the vessels of their own or on a time charter to minimize the cost of shipping their cargoes. The work is mainly concerned with the operational management problem of the fleet owned by a major oil company, a typical industrial carrier. The optimal fleet management problem for the major oil company can be divided into two phase problem. The front end corresponds to the production operation problem of the transportation of crude oil, the refinery operation, and the distribution of product oil to comply with the demand of the market. The back end is to tackle the fleet scheduling problem to meet the seaborne transportation demand derived from the front end. Relevant optimization models for each phase are proposed and described briefly. Then a user-friendly integrated fleet management support system is built based on the proposed optimization models for both ends under Windows environment. A case study reflecting the practices of fleet management problem for the major oil company is carried out by using the system.

• 한국경영과학회지
• /
• 제3권1호
• /
• pp.69-73
• /
• 1978

This paper deals with the problem of determining the optimal inventory-transportation policy of the idealistically simple inventory-transportation system with the following assumptions: (1) The system consists of a single central warehouse and a single local warehouse, (2) The planning horizon is finite, (3) Demand rate is fixed costant, and so forth. Developed is the algorithm by which to identify the optimal inventory policy which minimizes the total cost incurred to the system over the given finite planning horizon. A sample numerical example is presented along with a discussion of the possible applications of the approach used n the algorithm.