• Journal of Advanced Marine Engineering and Technology
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• v.8 no.1
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• pp.17-36
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• 1984

Since 1973, the competition on the development of fuel saving type internal combustion engines has become severe by the two times oil shock, and new type engines are reported every several months. Whenever these new type engines are developed, new designs are required and they will be offered in the market after performing the endurance test for a long time. But the engine market is faced with a heavy burden of finance, as the developing of a new engine requires tremendous expenses. For this reason, the computer simulation method has been lately developed to cope with it. The computer simulation method can be available to perform the reasonable research works by the theoretical analysis before carrying out practical experiments. With these processes, the developing expenses are cut down and the period of development is curtailed. The object of this study is the development of simulation computer program for the small naturally aspirated four-stroke diesel engine which is intended to product by the original design of our country. The process of simulation is firstly investigated for the ideal engine cycle, and secondly for the real engine cycle. In the ideal engine cycle, each step of the cycle is simulated by the energy balance according to the first law of thermodynamics, and then the engine performance is calculated. In the real cycle imulation program, the injection rate, the preparation rate and the combustion rate of fuel and the heat transfer through the wall of combustion chamber are considered. In this case, the injection rate is supposed as constant through the crank angle interval of injection and the combustion rate is calculated by the Whitehouse-Way equation and the heat transfer is calculated by the Annand's equation. The simulated values are compared with measured values of the YANMAR NS90(C) engine and Mitsubishi 4D30 engine, and the following conclusions are drawn. 1. The heat loss by the exhaust gas is well agree with each other in the lower load, but the measured value is greater than the calculated value in the higher load. The maximum error rate is about 15% in the full load. 2. The calculated quantity of heat transfer to the cooling water is greater than the measured value. The maximum error rate is about 11.8%. 3. The mean effective pressure, the fuel consumption, the power and the torque are well agree with each other. The maximum error is occurred in the fuel consumption, and its error rate is about 7%. From the above remarks, it may be concluded that the prediction of the engine performance is possibly by using the developed program, although the program needs to reform by adding the simulation of intake and exhaust process and assumping more reliable mechanical efficiency, volumetric efficiency, preparation rate and combustion rate.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.6
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• pp.533-542
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• 2003

This study aims to propose a simplified mathematical model for calculating vertical air temperature distribution in a four-sided atrium. In the first stage of the mathematical modeling, the computer model combined zonal model and solar radiation model using Monte Carlo method and Ray tracing technique went through a computer simulation with architectural variables applied to a four-sided atrium in summer. In the next stage, Curve Expert, a computer program that gets the most suitable solution ac-cording to the least squares method, is used to analyze the results of the computer simulation and to derive the mathematical model. The accuracy of the mathematical model was evaluated through a comparison of calculation results from a mathematical model and computer simulation. In this validation step using the least square method, the R2 value of the Zones 1, 2 and 3 showed higher than 0.945. Zone 4 has an R2 value of 0.911, lower than the previous three zones. However the relative error was below 0.5%, which is considered very small.

• 전기의세계
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• v.29 no.12
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• pp.798-803
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• 1980

A computer program for noise analysis of the audio circuit is developed. The application of the program to the equalizer, low frequency amplifier of radio circuit and cascaded amplifier show good results. The general noise analysis method for cascade operational amplifier is presented. The noise spectral power density is calculated for a resonator active filter.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.167-174
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• 1997

In this paper, the mathematical model of the hydraulic control valve is formulated, that is, this dynamic modeling which includes the motion equations and continuity equations can analyze the dynamic characteristics of the hydraulic control valve. The control valve for the transmission has the Over Speed Protection to protect a hydraulic travel motor. Therefore, this simulation shows the over speed protection and researches the main design parameters. The results of the computer simulation were assured through the experiment. From the comparison between both results, it is shown that this simulation program is useful and effective.

• Journal of the Korean Society for Railway
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• v.7 no.2
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• pp.120-124
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• 2004

Computer aided simulation is an essential part in planning, design, and operation of railway systems. To determine the adequate performance and specification of railway system, it is necessary to calculate train performances such as distance, speed, power during train's running. This paper presents result of train performance simulation using the program that developed for Korea high speed train. To verify result of simulation, we have compared that with experiment data.

• Journal of the Korea Society for Simulation
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• v.9 no.4
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• pp.77-85
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• 2000

The object of this paper is developing of a simulation model for performance evaluation of ai defense-gun system. We developed a three-step kill probability of areal target in case of one gun on one target considering : 1) estimating the target and warhead intercept point, 2) target vulnerability and 3) computing the kill probability. We used a Monte Carlo simulation method. This model can be used for probabilistic analysis giving results of sufficient accuracy with minimum requirement of input data. Also we developed a computer program according proposed algorithm and a set of experimental results using the proposed method are shown.

• Journal of the Korean Society of Safety
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• v.8 no.2
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• pp.23-29
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• 1993

In this study, the method of deciding simulation test conditions is developed by computer program compared to actual vehicle test as accurately as possible. These results of analytical test conditions are conformed by simulation test using the brake dynamometer by comparison with test results of actual vehicle. Results of simulation test by these analytical results show good agreement with the vehicle test results. The analytical simulation test conditions provide the input data to brake dynamometer which follows : - each test inertia corresponding to braking deceleration - test condition of input control : brake line pressure - test condition of output control : braking torque

• Journal of Biosystems Engineering
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• v.12 no.2
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• pp.1-15
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• 1987

A mathematical model is developed and computer programmed for simulation of power tiller motion. The model consists of a main body and two driving wheels resulting in an 8 degrees of freedom system. Drawbar loading is also included by coupling the model with a sub-model representing the implement to be used. The computer program SIMPTL can predict motion characteristics and static stability of power tiller under a given set of ground and operation conditions.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.377-379
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• 1997

This paper performed simulation of the Hybird power generation system and constructed a least component and analysis of the Hybird power system with computer program. In this paper, we performed simulation economic analysis of hybird power system.

• 전기의세계
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• v.26 no.1
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• pp.87-90
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• 1977

Various simulation techniques were developed in the modeling of biological system during the last decades. Mostly analog and hybrid simulation techniques have been used. The authors chose the Digital Analog Simulation (DAS) technique by using the MIMIC language to simulate the saccadic eye movement system performances on the digital computer. There have been various models presented by many investigators after Young & Stark's sampled-data model. The eye movement model chosen by the authors is Robinson's model III which shows the parallel information processing characteristics clearly to the double-step input stimuli. In the process of simulation, the parameter and constants used were based on the neurophysiological data of the human and animals. The analog model blocks were converted to the corresponding MIMIC block diagrams and programmed into the MIMIC statements. The program was run on the CDC Cyber 72-14 computer. The essential input stimulus was double-step of 5 and 10 degrees, and target durations chosen were 50,100 and 150 msec. The results obtained by the DAS technqiue were in good agreement with analog simulation carried out by other investigators as well as with the experimental human saccadic eye movement responses to double-step target movements.