• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2005년도 춘계학술대회 논문집
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• pp.129-133
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• 2005

This paper describes the methodology of connecting MASTER (Multi-purpose Analyzer for Static and Transient Effects of Reactors) to simulator system, system configuration, and previous test. The actual simulator environment for Youngkwang Unit1 has been developed. It is impossible for the simulator server to execute MASTER code by limitation of computer performance. So, environment of distributed system was developed, and it had a synchronization task. As MASTER and simulator module should be synchronized in different device, the connection of communication was tested and verified.

• 펄프종이기술
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• 제36권2호
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• pp.54-59
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• 2004

The methods for the minimization of fresh water consumption, waste water generation and water contamination have been greatly investigated and developed for last ten years. Recently, the rising cost of waste water treatment and the more strict environmental regulation lead to the higher demand of more efficient and systematic methods for process water management. The water reuse technology, which not only reduce the process water needs but also minimize waste water generation within the process, could be one of most efficient way for current demand. In this study, the practical way for reduction of water pollution and optimal reuse or recycle of process water in a newsprint mill was investigated by using a simulation model. The result of computer simulation showed that the COD level of approach system could be reduced by 50% after the stock concentration at the 2nd disc filter was increased upto 30%. The application of WRDF(Wrinkled Rotary Drum Filter) to the newsprint mill was carried out with pilot scale. The process water treated by WRDF had enough cleanliness to substitute the forming fabric shower water with the PDF water, which could result in the 30% reduction in fresh water consumption.

• 설비공학논문집
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• 제13권11호
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• pp.1089-1096
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• 2001

The cool-down performance after soaking is very important in an automotive air-conditioning system and is considered as the key design variable. Therefore, understanding of the overall transient characteristics of the system is essential to the preliminary design as well as steady-state characteristics. The objective of this study is to develop a computer simulation model and estimate theoretical1y the transient performance of an automotive air-conditioning system. To accomplish this, a mathematical modelling of each component, such as compressor, condenser, expansion valve, and evaporator, is presented first of all. For a detailed calculation, condenser and evaporator are divided into many subsections. Each sub-section is an elemental volume for modelling. In models of expansion valve and compressor, dynamic behaviors are not considered in an attempt to simplify the ana1ysis, but the quasi-static ones are just considered, such as the relation between mass flow rate and pressure drop in expansion device, polytropic process in compressor, etc. The developed simulation model is validated with a comparison to laboratory test data of an automotive air-conditioning system. The overall time-tracing properties of each component agreed fairly well wish those of test data in this case.

• International Journal of Control, Automation, and Systems
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• 제6권2호
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• pp.243-252
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• 2008

It has been reported that long-term exercise on a treadmill (running machine) may cause injury to the joints in a human's lower extremities. Previous works related to analysis of human walking motion are, however, mostly based on clinical statistics and experimental methodology. This paper proposes an analytical methodology. Specifically, this work deals with a comparison of normal walking on the ground and walking on a treadmill in regard to the external and internal impulses exerted on the joints of a human's lower extremities. First, a modeling procedure of impulses, impulse geometry, and impulse measure for the human lower extremity model will be briefly introduced and a new impulse measure for analysis of internal impulse is developed. Based on these analytical tools, we analyze the external and internal impulses through a planar 7-linked human lower extremity model. It is shown through simulation that the human walking on a treadmill exhibits greater internal impulses on the knee and ankle joints of the supporting leg when compared to that on the ground. In order to corroborate the effectiveness of the proposed methodology, a force platform was developed to measure the external impulses exerted on the ground for the cases of the normal walking and walking on the treadmill. It is shown that the experimental results correspond well to the simulation results.

• 에너지공학
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• 제24권4호
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• pp.217-222
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• 2015

A computer simulation has been developed to predict and investigate the performance of the assumed hydrogen engine. The simulation has be come a powerful tool as it saves time and also economical when compared to experimental study. The effects of various parameters, such as equivalent ratio, spark advance, revolutions per minute were calculated and then the optimal parameters of assumed engine were determined. The effects of spark advance, revolutions per minute, cylinder pressure, rate of pressure rise, flame temperature, rate of heat release, and mass fraction burned were simulated. The objective of the research paper is to develop a internal combustion model with hydrogen as a fuel.

• Journal of Advanced Marine Engineering and Technology
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• 제25권3호
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• pp.605-616
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• 2001

Generally, there are two methods in researching internal combustion engines. One is by experimental research and the other is by computer simulation. The experimental research has many merits that researchers can get data for engine performance, but it has also some demerit of cost and time. If there is an engine simulation code with accuracy for the solution, it is very convenient to predict the performance and optimum design value of the engine. In this study, engine performance simulation program has been improved to predict the transient variation of properties of gas in cylinder, intake and exhaust manifolds, There total program code was developed to calculate the pressure, flame factor and turbulent intensity, As a result of present study, the authors could predicted the in-cylinder pressure, intake manifold pressure and the engine performance in various conditions. The authors also could easily prepare the tool if optimum design of manifold and in-cylinder geometry.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.395-398
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• 1989

A two dimensional pseudo-homogeneous model for the methanol reforming reaction was developed and its steady and dynamic states were studied by a computer simulation. The reactor tube diameter, the catalyst density in the fixed bed, the feed flow rate, the feed temperature and the external temperature were chosen to be adjusted to determine the length of the reactor. The dynamics of the reactor showed that the system was highly nonlinear and sensitive to the feed disturbances.

• 한국정보통신학회논문지
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• 제13권7호
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• pp.1475-1482
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• 2009

본 논문에서는 최적의 Lab-on-a-Chip을 설계하기 위해 나선형 마이크로 채널에서 등속영동 프로틴 분리를 수행하는 컴퓨터 시뮬레이션을 이차원 유한 요소법을 이용하여 개발하였다. 개발한 이차원 ITP 모델은 다섯 가지 요소로 구성되며 Leader로서 염산을, Terminator로서 카르로산, 두 개의 프로틴 중 프로틴 A는 아세트산, 프로틴 B는 벤조산, 그리고 BE(Background Electrolyte)로서 히스티딘을 사용하였다. 컴퓨터 모델은 다섯 가지 구성 요소들에 대한 질량 보존 방정식과 전위에 대한 전하 보존 방정식, 그리고 pH 계산은 전기적 중성 조건식에 기반하고 있다. 제안된 이차원 공간 ITP 모델의 검증을 위해 제안한 모델의 결과와 Bohuslav Gas 그룹에서 개발한 Simu 5의 결과를 비교하였다. 시뮬레이션 결과 일차원 채널에서 두 모델이 매우 유사한 일치를 보임으로 제안한 모델의 정확성을 검증해 주었다. 이차원 프로틴 분리는 Lab-on-a-Chip 설계를 위한 이차원 곡선 채널에서 수행되어 채널 형상이 프로틴 포커싱분포(dispersions)의 변화를 초래함을 알 수 있었다.

• Nuclear Engineering and Technology
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• 제29권2호
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• pp.158-166
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• 1997

Integrated performance test of Chemical and Volume Control System 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 it 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 lese very well. Especially, the model was verified to be able to predict the "Stiction (composition of stick and friction)" 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 will be very useful for future plant design and test predictions.predictions.

• 대한산업공학회지
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• 제23권1호
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• pp.39-54
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• 1997

This paper presents four process models for machining processes : 1) an economical mathematical model of machining process, 2) a prediction model for surface roughness, 3) a decision model for fuzzy cutting conditions, and 4) a judgment model of machinability with automatic selection of cutting conditions. Each model was developed the economic machining, and these models were applied to theories widely studied in industrial engineering which are nonlinear programming, computer simulation, fuzzy theory, and neural networks. The results of this paper emphasize the human oriented domain of a nonlinear programming problem. From a viewpoint of the decision maker, fuzzy nonlinear programming modeling seems to be apparently more flexible, more acceptable, and more reliable for uncertain, ill-defined, and vague problem situations.