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

• 산업경영시스템학회지
• /
• 제23권58호
• /
• pp.17-27
• /
• 2000

In FMS where tool movement policy is adopted, a mathematical model has been developed which determines the selection of a tool type for each operation and tool loading-part assignment simultaneouly. The objective is to minimize the total cost of operation including machining time cost, tool cost, tool replacement and loading time cost, and tool change time cost. Due to the complexity of the problem, an approximate solution procedure has been developed utilizing the special structure of the model. Tool selection was determined first to allocate one tool type to each operation considering more than one tool type alternatives for each operation. Tool loading-part assignment was determined to minimize tile total number of tool changes due to part mix based on the tool selection.

• Nuclear Engineering and Technology
• /
• 제55권3호
• /
• pp.1167-1180
• /
• 2023

Due to the tightened regulatory environment since the Fukushima accident, the capacity factor of Korean nuclear power plants has been declining since 2011. To overcome this circumstance, a shift from 18-month to 24-month cycle operation is being considered in Korea. Therefore, in this study, loading patterns(LPs) for 24-month cycle operation of the Korean standard nuclear power plant(OPR-1000) are suggested and economic evaluations are performed. A single-zone LP with 89 fresh fuels was evaluated to be optimal for 24-month operation of OPR-1000 in terms of economic gain. The 24-month operation of OPR-1000 with this LP gives a profit of 7.073 million dollars per year compared to 18-month operation.

• 한국통신학회논문지
• /
• 제35권4A호
• /
• pp.315-321
• /
• 2010

Ad-hoc 네트워크에서는 전력을 제어할 기지국의 부재로 시스템의 성능을 최적화 시키는 중앙 전력 제어가 불가능하여, 각 노드들은 독립적이고 자동적인 방식으로 분산형 전력 제어 알고리즘을 수행해야 한다. 기존의 분산형 전력 제어 알고리즘은 수신 신호의 SINR (signal to interference and noise ratio)에 따라 MCS (modulation and coding scheme) 레벨을 변화 시키는 adaptive bit loading operation을 고려하지 않기 때문에, 전체 throughput 향상에 제한이 있다. 본 논문에서는 Ad-hoc 환경에서 전체 throughput 을 향상시키고, outage 확률을 낮추기 위해 MCS 레벨에 따라 adaptive bit loading operation을 고려한 분산형 전력 제어 알고리즘을 제안한다. 컴퓨터 모의실험 결과 매우 큰 throughput 향상과 outage 확률 감소의 성능 향상을 확인할 수 있다.

• 한국수산과학회지
• /
• 제37권4호
• /
• pp.330-336
• /
• 2004

To meet the increasing demand from various fishing fields for training of fishing equipment operators, a fishing winch simulator was designed to train maritime students in the correct and safe operation of hydraulic winches under various load conditions related to fishing operations. The aim of this study is to describe the basic dynamic characteristics of the newly developed hydraulic fishing winch simulator and particularly to analyze the mechanical responses produced on the winch operation controls. The winch simulator consists of two winch units, a computer control and data acquisition system, a control consol and other associated mechanisms. When one winch is in hauling mode, the other one will always be in loading mode. The revolution speed of the hauling winch was controlled by a proportional directional control valve, and the braking torque of the loading winch was controlled by a proportional pressure control valve. The simulation experiments indicated that the dynamic characteristics of the hauling winch followed the braking response characteristics of the loading winch. The tests also showed that the warp speed and tension linearly depend on the pressure differential across the motor of the loading winch controlled by operating the proportional pressure control valve during the hauling operation. The experience gained from various training courses showed that the fishing winch simulator was very realistic and it was valuable for training novice winch operators. The results of the winch simulation exercise were recorded and used to evaluate the training on the operation and handling of the winch system. From these test results, we concluded that the tension acting on the warp during hauling operations can successfully be simulated by controlling the pressure differential across the motor with step changes of the control input signal to the proportional pressure control valve of the loading winch.

• 한국환경과학회지
• /
• 제11권8호
• /
• pp.783-791
• /
• 2002

A laboratory-scale dual-column biofilter system was used to study the biofiltration of dimethyl disulfide(DMDS). The biofiltration of DMDS was found to depend on the pollutant loadings rather than the inlet concentrations. It was estimated that the pollutant was only inhibitory to the operation of the biofilters at DMDS concentrations greater than 5500 ppmv A residence time of 30 seconds(120 m$^3$/m$^2$/h volumetric loading) was determined as appropriate for efficient operation(>90%). The maximum elimination capacity for both compost mixtures under the current experimental conditions was found to range from 7.5 to 10 g-DMDS/m$^3$/h. A lower DMDS maximum elimination capacity was exhibited under acidified conditions.

• 한국컴퓨터정보학회논문지
• /
• 제10권1호
• /
• pp.201-208
• /
• 2005

오늘날 컨테이너터미널의 운영방식의 변화를 통해 컨테이너터미널의 효율을 증대시키기 위한 대처방안에 대한 연구가 활발히 이루어지고 있다. 컨테이너터미널의 효율을 증대시키기 위해서는 적하계획 수립이 상당히 중요한 역할을 한다. 적하계획은 크게 적재의 위치를 결정하는 문제와 적재의 순서를 결정하는 문제로 나눌 수 있는데, 본 논문에서는 보다 효율적인 적재순서 결정 방안을 제시한다. 컨테이너 적재순서 결정 문제는 장치위치 및 운영 장비 등 여러 가지 경우의 수를 고려해야 하는 조합 최적화 문제이다. 컨테이너 적재순서를 결정하는 기존의 클러스터 구성방식은 재처리 문제로 작업의 효율성을 높이는데 한계가 있다. 따라서 선적지시서와 야드맵을 기초로 동일한 속성을 가진 컨테이너들을 계층적 클러스터링 방법을 적용하여 스택단위의 클러스터로 구성하고, 작업순서의 제약을 정의하는 보다 효율적인 컨테이너 적재순서결정 방법을 제안한다. 그 과정에서 작업순서 제약을 정의함으로서 클러스터간의 가능한 작업경로를 파악할 수 있고, 작업경로에 대한 제약적 탐색이 가능하여 기존의 방식에 비해 탐색효율이 증가됨을 알 수 있다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 춘계학술대회논문집A
• /
• pp.426-432
• /
• 2000

The hydraulic loading system real-time simulator using a PC and I/O interface board is developed to simulate the dynamic characteristics of hydraulic loading system in real time. The simulator receives the digital on-off control signals generated by the operator through the D/I channels, updates the state and output variables of the hydraulic loading system responding to the input signals and draw the moving pictuters of the lift cylinder, lift arm and loading box on the PC monitor in real time. Also, the operator can observe the displacement and pressure of cylinder, the rotatinal angle, reaction force, and safety factors of lift arm representing the operation of hydraulic loading system through the PC monitor in real time. The real-time simulator can be a very useful tool to design industrial dynamic systems and feel the goodness of the system operation since the operator can observe the moving pictures of the operating system in real time as he operates the real time simulator.

• 한국항해항만학회지
• /
• 제43권3호
• /
• pp.197-208
• /
• 2019

공 컨테이너 장치장의 사양, 취급 장비, 운영방법이 공 컨테이너 적하 시 발생할 수 있는 재취급 기대횟수에 미치는 영향을 연구하였다. 다수 선사의 다양한 유형의 공 컨테이너를 서로 분리된 공간에 저장한다면 저장 공간을 충분히 활용할 수 없고, 저장 공간의 활용도를 높이기 위해 여러 선사의 공 컨테이너를 혼적하여 함께 저장한다면 적하작업 중에 추가로 재취급이 발생할 수 있다. 한 베이에서 적하작업을 위하여 공 컨테이너를 인출하는 시점에 기대되는 재취급 횟수를 계산하기 위해 필요한 여러 가지 수식을 유도하였다. 트랜스퍼 크레인과 탑 핸들러를 취급 장비로 간주하여 다양한 인출 전략을 검토하였다. 장치장의 다양한 설계 및 운영 매개 변수가 재취급 횟수에 미치는 효과를 확인할 목적으로 수치실험을 수행하였다.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 1998년도 추계학술대회논문집:21세기에 대비한 지능형 통합항만관리
• /
• pp.167-174
• /
• 1998

Recently several researches of high speed container ship and loading system are mainly accomplished in U.S.A. and Japan. Its shipping service is not realized but it is realized in near future. To effective use of the feature and efficiency of them, quay, loading/unloading. yard operation system, port management system and connection transport system must be well integrated and operated. Specially, loading /unloading speed of container crane is important for making effective use of them. To speed up loading/unloading system, RO-RO and LO-LO methods that are mostly exclusive system are studied on the container crane with special structure and mechanism to handle individual container or bundle of containers. In this paper these methods are shown. When new high speed loading system of container is desighed, the realistic constrains must be considered.