• 대한조선학회논문집
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• 제53권1호
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• pp.18-28
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• 2016

In shipbuilding, the scheduling system is susceptible to sudden changes and thus it turns to be difficult to predict the differences between schedule and production records in advance. A computer-based simulation is commonly utilized to overcome the discrepancies occurred in estimating workloads and resulting processing times. The main drawback of this simulation-based solution is its limited applicability because, in most cases, each shipyard requires specific and customized simulation environment. By standardizing the planning data of the midterm scheduling system, as proposed in this paper, the efficiency of the current simulation model can be enhanced. To present an alternative approach, this paper begins with the analysis of the complex planning data structure of several shipyards and then proceeds to construct a standard data structure based on the neutral format. An interface application is developed for the data transaction and simulation in on-line environment. As a result, a simulation-based production management of shipyards can be achieved by the efficient prediction of planning and scheduling.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.1072-1079
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• 2014

This paper introduces a coordinated droop control for the stand-alone DC micro-grid, which is composed of photo-voltaic generator, wind power generator, engine generator, and battery storage with SOC (state of charge) management system. The operation of stand-alone DC micro-grid with the coordinated droop control was analyzed with computer simulation. Based on simulation results, a hardware simulator was built and tested to analyze the performance of proposed system. The developed simulation model and hardware simulator can be utilized to design the actual stand-alone DC micro-grid and to analyze its performance. The coordinated droop control can improve the reliability and efficiency of the stand-alone DC micro-grid.

• Journal of Communications and Networks
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• 제14권6호
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• pp.614-618
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• 2012

Smart grid is widely considered to be a next generation power grid, which will be integrated with information feedback communications.However, smart grid communication technologies are subject to inefficient spectrum allocation problems. Cognitive radio networks can solve the problemof spectrumscarcity by opening the under-utilized licensed bands to secondary users. In this paper, adaptive cognitive radio spectrum sensing and sharing algorithms are developed for smart grid environments. Simulation results are presented to demonstrate the effectiveness of the proposed scheme in comparison with other existing schemes.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(1)
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• pp.425-432
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• 1996

Integrated performance test of Chemical and Volume Control System (CVCS) was successfully performed in 1994. However, an extensive effort to correct hardware and software problems in the letdown line was required mainly due to the lack of adequate simulation code to predict the test accurately. Although the LTC computer code was used during the YGN 3'||'&'||'4 NSSS design process, the code can not satisfactorily predict the test due to its insufficient letdown line modeling. This study developed a numerical model to simulate the letdown test by modifying the current LTC code, and then verified the model by comparing with the test data. The comparison shows that the modified LTC computer code can predict the transient behavior of letdown system tests very well. Especially, the model was verified to be able to predict the "Stiction" phenomena which caused instantaneous fluctuations in the letdown backpressure and flowrate. Therefore, it is concluded that the modified LTC computer code with the ability of calculating the "Stiction" phenomena wi11 be very useful for future plant desist and test predictions.predictions.

• 한국시스템다이내믹스학회:학술대회논문집
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• 한국시스템다이내믹스학회 2006년도 춘계학술대회 발표논문집
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• pp.101-122
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• 2006

A series of system dynamics model was developed for forecasting demand and supply of human resource in the electricity industry. To forecast demand of human resource in the electric power industry, BLS (Bureau of Labor Statistics) methodology was used. To forecast supply of human resource in the electric power industry, forecasting on the population of our country and the number of students in the department of electrical engineering were performed. After performing computer simulation with developed system dynamics model, it is discovered that the shortage of human resource in the electric power industry will be 3,000 persons per year from 2006 to 2015, and more than a double of current budget is required to overcome this shortage of human resource.

• 한국정보통신학회논문지
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• 제26권4호
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• pp.541-547
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• 2022

가상현실을 활용한 실감형 교육은 전통적 학습에 비하여 몰입과 상호작용을 통해 학생들의 지식 이해도를 높일 수 있다. 기존의 연구에서 가상현실 교육은 주로 경험에 중점을 두었고, 환경 교육을 위한 가상현실 콘텐츠는 많이 개발되지 않았다. 환경 문제는 전 세계적인 문제로 환경 교육은 미래를 위해 필수적이다. 본 연구에서는 환경교육의 중요성을 인식하고 환경 친화적인 행동에 참여할 수 있도록 설계된 몰입형 가상현실 기반의 환경교육 시뮬레이션을 개발했다. 이 시뮬레이션은 가상생태계 모델을 기반으로 하여 환경 요인간의 인과관계와 시공간적 연계와 지속적인 상태를 유지하고 있다. 사용자는 가상에서 환경 요인에 관련된 인터랙션에 따른 결과를 경험하면서 환경 문제를 직관적으로 인식하고 해결 방법에 대한 동기부여를 받는다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2000년도 춘계학술대회 논문집(Proceeding of the KOSME 2000 Spring Annual Meeting)
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• pp.36-44
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• 2000

In his study the simulation was carried out by simplifing and modeling dividing into fuel injectioin pump high pressure pipe and fuel injection valve in the fuel injection system of a low speed marine diesel engine. A computer simulation model was developed using the method of characteristics to analyze the unsteady flow in the fuel injection system considering cavitation and variation of fuel density and bulk modulus. Comparison was commenced between the calculated data and experimental data of pressure and injection quantity at the high pressure distributor in fuel injection system for the training ship "M/V hanara" the effects of the high pressure pipe length diameter plunger diameter nozzle openning pressure were also investigated by simulating results.g results.

• 한국통신학회논문지
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• 제21권10호
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• pp.2605-2619
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• 1996

In this paper, we evaluated performance of mobile exchange control part. Queueing network model is used for modeling of mobile exchange control part. We developed a call control processing and location registration scenartio which has a message exchange function between processors in mobile exchange control part. A network symbol are used the simulation models that are composed of the initialization module, message generation module, message routing module, message processing module, message generation module, HIPC network processing module, output analysis module. as a result of computer simulation, we obtain the processor utilization, the mean queue length, the mean waiting time of control part based on call processing and location registration capacity. The call processing and location registration capacity is referred by thenumber of call attempts in the mobile exchange and must be satisfied with the quality of service(delay time).

• 대한전자공학회논문지SD
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• 제41권1호
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• pp.71-80
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• 2004

본 논문에서는 집적회로 패키지에 기인한 노이즈를 해석할 수 있는 새로운 SSN모델을 보인다. 기존의 디커플링 커패시터를 고려하지 않은 회로모델은 과도하게 SSN을 예측한다는 것을 보였으며, 디커플링 커패시터가 포함된 패키지 회로모델을 통하여 새로운 SSN 모델을 제안하였다. 새롭게 제안된 SSN 모델은 0.18um공정(TSMC 0.18um공정)을 사용하여 다양한$\cdot$회로설계 변수(입력상승시간, 패키지 인덕턴스 및 동시 스위칭 개수)의 변화에 따라 HSPICE 시뮬레이션과 정확히($5\%$ 이내에서) 일치한다는 것을 검증하였다.

• 한국자동차공학회논문집
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• 제4권6호
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• pp.205-215
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• 1996

In this paper, the performance analysis of the vehicle with the Ravigneaux type automatic transmission has been carried out using information of engine and drivetrain. It is necessary to understand the overall system including engine, torque converter, clutch, planetary gears, and road load. The equations of motion are derived from dynamic model. The GUI computer simulation program has been developed to analyze the powertrain performance of the vehicle with the Ravigneaux type automatic transmission.