• 제목/요약/키워드: operation research

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A Simulation Model for Improving the Productivity of Container Handling in the Container Terminal

  • Park, Nam-Kyu;Lee, Sang-Wan;Park, Hyung-Rim;Kwon, Hae-Kyoung
    • Journal of Navigation and Port Research
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    • v.28 no.4
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    • pp.285-291
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    • 2004
  • The productivity of container terminal is determined by its various operation methods. This paper aims at finding out the factors to enhance the productivity of container handling of quay crane, using simulation technique. Three levels of decision making in terminal operation, strategy, and tactics and operation are selected for defining parameters of simulation The result of the simulation and test shows that the significant factors to improve the productivity are the stack height of container, block dispersion and the distance in yard planning for shipment. Decision making in the operation level, however, is of significance in the mixed condition of strategic and tactical level. The result shows meaningful guidelines in decision making under strategic, tactical and operation level.

Constitution and Operation of the 25 kW Molten Carbonate Fuel Cell Power Generation System for Power Utility (25 kW급 전력사업용 MCFC 발전시스템 구성 및 운전평가)

  • Lim, Hee-Chun;Ahn, Kyo-Sang
    • Proceedings of the KIEE Conference
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    • 2000.07b
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    • pp.687-689
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    • 2000
  • Molten Carbonate Fuel Cell (MCFC) with high electrical efficiency and low environmental effect has been developed for the commercial application of power generation fields. Recently we have built a 25 kW molten carbonate fuel cell power generation system and tested it. The MCFC system is composed of diverse peripheral units such as reformer, pre-heater, water purifier. electrical loader, gas supplier, and recycling systems. The stack itself was made of 40 cells of $6.000 cm^2$ area each. The stack showed an output of 28.6 kW power and a reliable performance at atmospheric operation. while in pressurized operation the stack showed an output 25.6 kW lower than the atmospheric operation. The reason of lower performance of pressurized operation was caused from a gas cross over shown in few cells in the stack.

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On the Service Improvement of High-Density Urban Railway Transportation (고밀도 도시철도 운행품질 개선 방안 연구)

  • Kim, Dong-Hee
    • Journal of the Korea Safety Management & Science
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    • v.12 no.3
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    • pp.163-168
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    • 2010
  • Recently, there are many problems of service qualities such as regular-rapid-safe -comfortable transport, that was traditionally advantages in urban railway transportations. These problems cause train delays that affects consecutive schedule, capacity, operation plans, and it is hard to prevent the propagation of delay and find the recovery solution. Because the urban transport demands is continuously increased and the railway service is also expanded, the railway operation company makes efforts to improve operation performance and efficiency for passengers. In this paper, we analyse the issues and problems existing in the major operation line of high-density urban railways, and suggest the development direction of intelligent operation technology to improve the urban railway service by minimizing the occurrence and propagation of delay. And the result of numerical case study is also presented.

Launch Site Activities for the Launch of an Earth Observation Satellite

  • Im, Jeong-Heum
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.2
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    • pp.195.1-195.1
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    • 2012
  • Korea Aerospace Research Institute has developed an earth observation satellite whose primary mission objective is to provide high resolution electro optical earth images for Geographical Information Systems (GIS) establishment and the applications for environmental, agriculture and ocean monitoring. It was successfully launched into its mission orbit by using a commercial launch vehicle on 18th of May, 2012. This paper describes a series of launch activity at the launch site including its transportation to the launch site. Before conducting the launch site operation, satellite operation plane was prepared. Combining the satellite operation plan and launch vehicle activities, an integrated launch site operation plan and schedule have been drawn up. After arrival of the spacecraft at the launch site, post-ship check out has been conducted. And then it was fuel loaded and integrated with launch vehicle hardware. After completion of final electrical check out, count down procedure was executed. on 18th of May, it was launched into the space and was separated from the launch vehicle as planned. About 3 months of early operation and calibration/validation, now the satellite is conducting its normal mission.

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A Study of Critical Success Factors in System Development Team Operation (시스템 개발프로젝트에 있어서 팀제도 운영의 성공요인분석)

  • 이재정;박문규
    • The Journal of Information Systems
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    • v.8 no.2
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    • pp.169-185
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    • 1999
  • The overall objective of this study is to empirically investigate organizational/managerial factors affecting system development team operation. The contributions of this research project are two-fold. First, this study examined various organizational/managerial factors that made team operation successful. Second, we presented the key success factors among the identified success factors of team operation. A field investigation of 68 system development teams located around YoungNam area indicates that motivation, leadership and egalitarian team culture are success factors of team operation. Especially, key success factors are leadership and egalitarian team culture.

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Improvement of Drought Operation Criteria in Agricultural Reservoirs (농업용 저수지 이수관리를 위한 저수율 가뭄단계기준 개선)

  • Mun, Young-Sik;Nam, Won-Ho;Woo, Seung-Beom;Lee, Hee-Jin;Yang, Mi-Hye;Lee, Jong-Seo;Ha, Tae-Hyun
    • Journal of The Korean Society of Agricultural Engineers
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    • v.64 no.4
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    • pp.11-20
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    • 2022
  • Currently, the operation rule of agricultural reservoirs in case of drought events follows the drought forecast warning standard of agricultural water supply. However, it is difficult to preemptively manage drought in individual reservoirs because drought forecasting standards are set according to average reservoir storage ratio such as 70%, 60%, 50%, and 40%. The equal standards based on average water level across the country could not reflect the actual drought situation in the region. In this study, we proposed the improvement of drought operation rule for agricultural reservoirs based on the percentile approach using past water level of each reservoir. The percentile approach is applied to monitor drought conditions and determine drought criteria in the U.S. Drought Monitoring (USDM). We applied the drought operation rule to reservoir storage rate in extreme 2017 spring drought year, the one of the most climatologically driest spring seasons over the 1961-2021 period of record. We counted frequency of each drought criteria which are existing and developed operation rules to compare drought operation rule determining the actual drought conditions during 2016-2017. As a result of comparing the current standard and the percentile standard with SPI6, the percentile standard showed severe-level when SPI6 showed severe drought condition, but the current standard fell short of the results. Results can be used to improve the drought operation criteria of drought events that better reflects the actual drought conditions in agricultural reservoirs.

Conatiner Terminal Operation Method for the Efficient Dual Cycle Operation (효율적인 듀얼 사이클을 위한 터미널 운영방법)

  • Chung, Chang-Yun;Shin, Jae-Young
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2010.10a
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    • pp.110-111
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    • 2010
  • Recently, container terminal managers make an experiment on the double cycle and dual cycle operation, which ship loading and unloading were carried out simultaneously, for increasing the productivity of quay side. However, if we make an experiment on dual cycle operation in a real job site, the efficiency is poor up to terminal operation method as YTs(Yard Tractors)' allocation method, QCs(Quay Cranes)' working speed, and position of export containers. So, this paper examine more efficient terminal operation method, when terminal uses dual cycle operation.

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An Evaluation of Productivity Improvement for Container Terminal by Operation System (운영시스템에 의한 컨테이너터미널의 생산성 향상 평가)

  • 최용석;하태영
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2004.04a
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    • pp.385-392
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    • 2004
  • The objective of this study is to evaluate the effectiveness of new operation system for port container terminals. We assumed that the operation system of container terminal consists of monitorig & control system, operation system, planning system, and information technology, and we selected total 19 technology alternatives. Through the results of questionnaire and interview received from field expert, we established the evaluation model and analyze the productivity improvement by estimating the weight and the priority of productivity for operation system. From the developed model, we provide useful implications to introduce new technologies of operation system for domestic container terminals.

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Study on Motor Characteristics due to Deviation of the Wheel Diameters with Parallel Operation

  • Lee, Hyung-Woo
    • Journal of Electrical Engineering and Technology
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    • v.8 no.1
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    • pp.106-109
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    • 2013
  • It is desirable and advantageous to feed parallel propulsion with induction motors by a single voltage source inverter. However, effects of deviation of the wheel diameters on motor current, rotor speed and torque should be also considered for parallel operation. In order to understand the behavior and characteristics, a simple simulation model is developed by using a commercial Matlab Simulink. From the results, it is clear to manage the diameter deviation of the wheels which are connected to traction motors.

Analysis of Tilting Angle of KOMPSAT-1 EOC Image for Improvement of Geometric Accuracy Using Bundle Adjustment

  • Seo, Doo-Chun;Lee, Dong-Han;Kim, Jong-Ah;Kim, Yong-Seung
    • Proceedings of the KSRS Conference
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    • 2002.10a
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    • pp.780-785
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    • 2002
  • As the KOMPSAT-1 satellite can roll tilt up to $\pm$45$^{\circ}$, we have analyzed some EOC images taken at different tilt angles fur this study. The required ground coordinates for bundle adjustment and geometric accuracy, are read from the digital map produced by the National Geography Institution, at a scale of 1:5, 000. These are the steps taken for the tilting angle of KOMPSAT-1 satellite to be present in the evaluation of the accuracy of the geometric of each different stereo image data: Firstly, as the tilting angle is different in each image, the satellite dynamic characteristic must be determined by the sensor modeling. Then the best sensor modeling equation is determined. The result of this research, the difference between the RMSE values of individual stereo images is due more the quality of image and ground coordinates than to the tilt angle. The bundle adjustment using three KOMPSAT-1 stereo pairs, first degree of polynomials for modeling the satellite position were sufficient.

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