• 한국시뮬레이션학회논문지
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• 제28권4호
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• pp.45-56
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• 2019

장치장 운영전략을 주제로 한 많은 선행연구들은 장치장에 도착한 트럭들을 대상으로 야드 크레인의 작업시간을 최소화할 수 있는 작업순서를 결정했다. 하지만 실제 현장에서는 이미 장치장에 도착한 트럭들의 작업순서를 바꾸는 것은 거의 불가능하여, 도착순서에 따라 작업을 처리해주는 비교적 단순한 전략을 주로 적용해왔다. 이 방식은 작업순서에 대한 혼잡을 줄일 수 있고 관리가 편하다는 장점이 존재하지만, 간섭대기시간과 공차시간의 증가로 작업시간이 증가하는 문제점이 있다. 본 연구에서는 트럭이 야드 장치장에 도착하기 이전에 트럭의 작업 순서를 결정하는 스케줄링 방법을 제안했다. 트럭 도착 이전에 작업을 할당해 주기 위해 트럭의 도착 예정 시간을 추정할 수 있는 Container Pre-Information Notice 정보를 활용하였다. 연구에서 제안하는 스케줄링 방법의 효과성을 검증하기 위해 실제 부산컨테이너터미널의 설비 레이아웃 및 데이터를 이용하여 현업의 방식과 본 연구의 스케줄링 방식을 비교하였다. 그 결과 크레인 작업 시간에 영향을 미치는 공차이동 및 간섭 대기시간이 감소하여 평균 작업 처리 시간이 감소한 것을 확인하였으며, 또한 내부트럭의 대기시간과 외부트럭의 체감 대기시간이 감소하는 효과가 있었다.

• 대한산업공학회지
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• 제33권3호
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• pp.290-302
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• 2007

This paper introduces several decision-making problems that need to be solved in order to facilitate the efficient operation of container terminals. These decision-making problems include the berth planning problem, the quay crane scheduling problem, the unload/load sequencing problem, the yard allocation problem, and the short-term scheduling of transporters and yard cranes. These problems can be classified into strategic decision problems, tactical decision problems, and real time operational decision problems. This paper proposes definitions of the problems that can be used to develop mathematical models for the problems.

• 산업경영시스템학회지
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• 제41권4호
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• pp.238-247
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• 2018

This paper considers the problem of scheduling loading and unloading operations of a crane in a railway terminal motivated from rail-road container transshipment operations at Uiwang Inland Container Depot (ICD). Unlike previous studies only considering the total handling time of containers, this paper considers a bi-criteria objective of minimizing the weighted sum of the total handling time and tenant service time. The tenant service time is an important criterion in terms of terminal tenants who are private logistics companies in charge of moving containers from/to the terminal using their trucks. In the rail-road container shipment yard, the tenant service time of a tenant can be defined by a time difference between beginning and finishing loading and unloading operations of a crane. Thus, finding a set of sequences and time of the crane operations becomes a crucial decision issue in the problem. The problem is formulated as a nonlinear program which is improved by linearizing a nonlinear constraint in the model. This paper develops a genetic algorithm to solve the problem and performs a case study on the Uiwang ICD terminal. Computational experiment results show that the genetic algorithm shows better performance than commercial optimization solvers. Operational implications in terms of tenants are drawn through sensitivity analyses.

• 산업공학
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• 제24권4호
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• pp.362-372
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• 2011

Container pick-up scheduling problem is to minimize the total container handling time, which consists of the traveling distance and the setup time of yard cranes in a container yard. Yard cranes have to pick-up the containers which are stacked in the yard-bays to satisfy the work schedule requirement of quay crane, which loads and unloads containers on or from container ships. This paper allows the movement of multiple yard cranes among storage blocks. A mixed integer programming model has been formulated and a genetic algorithm (GA) has been proposed to solve problems of large sizes. Computational results show that the proposed GA is an effective method.

• 한국항해항만학회지
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• 제31권10호
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• pp.869-877
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• 2007

본 논문은 교행이 불가능한 두 대의 자동화 크레인을 운영하는 자동화 컨테이너 터미널의 장치장을 대상으로 국지적 탐색 알고리즘을 이용해 실시간 작업계획을 수립하는 방안을 제안한다. 제안방안은 실시간 제약조건을 만족시키기 위해 현재 이후 일정 시간의 작업만을 작업 계획의 대상으로 삼으며, 장치장의 동적인 작업 특성을 고려하여 새로운 작업이 요청될 때마다 작업 계획을 다시 수립한다. 또한, 교행이 불가능한 두 대의 크레인을 운영할 때 발생할 수 있는 크레인 간의 작업 부하 불균형을 해소하기 위해 작업 계획 과정에서 상대 크레인에 의한 사전 재취급과 사전 이적을 통한 두 크레인 간의 협업을 가능하게 하였다. 시뮬레이션을 이용한 실험 결과 제안 방안이 휴리스틱 방안에 비해 우수하며, 크레인 간의 협업이 작업 효율 향상에 도움이 됨을 확인하였다.

• International Journal of Internet, Broadcasting and Communication
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• 제7권1호
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• pp.1-5
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• 2015

In this study, we consider the transportation problem in port container terminals. It aims to determine positions in yards to place the containers at the adequate times. The containers on ship must be unloaded one by one from top to bottom, and placed in the main yard in order to reduce additional cost required for unnecessary unloading when getting out by customer with given timetable. The cost for transportation at container terminals could be reduced by a new approach in scheduling: move the containers from ship and stack them onto main yard that minimizes cost of yard crane operation when unloading for customer.

• 한국항해항만학회지
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• 제33권8호
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• pp.555-562
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• 2009

컨테이너 터미널의 주요 생산성 지표는 안벽에서의 작업 효율성이라 할 수 있다. 안벽에서는 Q/C(Quay Crane)이라는 장비가 접안 선박의 컨테이너를 하역한다. Q/C의 작업 생산성을 높이기 위해서는 좀 더 효율적인 Y/T(Yard Tractor)운영 방식이 필요하다. 기존 작업 방식(싱글 사이클)에서는 양하작업 이후 적하 작업이 이루어진다. 듀얼 사이클이란 양하작업과 적하 작업을 동시에 함으로써 안벽 생산성과 야드 트랙터의 이용률을 높이는 방법이다. 터미널에서 듀얼 사이클의 도입은 추가적인 장비의 도입 없이 운영에서의 변화만을 요구한다. 즉, 기존의 dedicate 시스템에서 pooling 시스템으로의 변화가 필요하다. 본 논문에서는 듀얼 사이클을 이용하는 항만에서의 작업 효율성을 증대시키기 위한 선적 계획 방법을 제시하고자 한다. 이 문제를 풀기위해 유전 알고리즘과 타부서치를 제시하였다.

• 대한산업공학회지
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• 제23권4호
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• pp.645-660
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• 1997

An application of the genetic algorithm(GA) to the loading sequencing problem in port container terminals is presented in this paper. The efficiency of loading operations in port container terminals is highly dependent on the loading sequence of export containers. In order to sequence the loading operation, we hove to determine the route of each container handling equipment (transfer crane or straddle carried in the yard during the loading operation. The route of a container handling equipment is determined in a way of minimizing the total container handling time. An encoding method is developed which keeps intermediate solutions feasible and speeds up the evolution process. We determine the sequence of each individual container which the container handling equipment picks up at each yard-bay as well as the visiting sequence of yard-bays of the equipment during the loading operation. A numerical experiment is carried out to evaluate the performance of the algorithm developed.

• 산업공학
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• 제24권1호
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• pp.78-86
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• 2011

To mitigate space restriction and to raise productivity, some shipbuilding companies use floating-docks on the sea instead of dry-docks on the land. In that case, a floating-crane that can lift very heavy objects (up to 3,600 tons) is used to handle the blocks which are the basic units in shipbuilding processes, and so, very large blocks (these are called the mega-blocks) can be used to build a ship. But, because these mega-blocks can be made only in the area near the floating-dock and beside the sea, the space is very important resource for the process. Therefore, our problem is to make an efficient spatial schedule for the mega-block assembly yard. First of all, we formulate this situation into a mathematical model and find optimal solution for a small problem using a commercial optimization software. But, the software could not give optimal solutions for practical sized problems in a reasonable time, and so we propose a GA-based heuristic algorithm. Through a numerical experiment, finally, we show that the spatial scheduling algorithm can provide a very good performance.

• 산업공학
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• 제13권2호
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• pp.225-233
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• 2000

In this paper, we develope a genetic algorithm for the erection scheduling in shipbuilding. Erection, the final manufacturing stage of shipbuilding, involves the landing and joining of blocks at drydock. Since several ships are built simultaneously at the same drydock and they compete with the common constrained production resource such as labor, space, and crane, we should consider both ship-specifics and common resource constraints for the desirable erection scheduling. Ship erection should also satisfy the predetermined dock cycle given from higher level production planning. Thus, erection schedule of a ship can be represented as a PERT/CPM project network with its own deadline. Since production resources are shared, the erection scheduling become the so-called multi-project scheduling problem with limited resources, which can not be solved easily due to the large size of project network. We propose a function as a minimization of load index which represented the load deviation over time horizon considering the yard production strategy. For the optical parameter setting, we tried various experiments. We verified that the proposed approach was effective to deal with the erection scheduling problem in shipbuilding.