• Journal of the Korea Society for Simulation
• /
• v.4 no.1
• /
• pp.25-36
• /
• 1995

We develop a variance reduction technique in one simulation experiment whose purpose is to estimate the parameters of a first-order linear model. This method utilizes the control variates obtained during the course of simulation run under Schruben and Margolin's method (S-M method). The performance of this method is shown to be similar in estimating the main effects, and to be superior to S-M method in estimating the overall mean response in the hospital simulation experiment. For the general case, we consider that a proposed method may yield a better result than S-M method if selected control variates are highly correlated with the response at each design point.

• Proceedings of the KSME Conference
• /
• 2001.06b
• /
• pp.428-435
• /
• 2001

In this paper, the design factors of stacker crane for the automatic warehouse are verified by dynamic simulation process. Simulation model is designed as the form of rigid elements and discrete flexible beam connections. The various result for structural design of stacker crane is produced by dynamic simulation and experiment. For the simulation of structural dynamics, ADAMS which is a software for kinematic & dynamic simulation, is used. In order to verify the analysis method, simulation and experiment result are compared.

• The Journal of Korean Academic Society of Nursing Education
• /
• v.13 no.1
• /
• pp.5-12
• /
• 2007

Purpose: The purposes of this study were to investigate nursing students' attitudes toward the elderly and to explore the effects of senior simulation on nursing students' attitudes. Method: For the purpose of the study, the program was performed on 223 nursing students in Gyung-gi. An Aging Semantic Differential Scale was utilized to evaluate attitudes toward the elderly. The senior simulation equipment consisted of a special spacesuit, glasses, gloves, and sand bag. Before and after the experiment subjects filled out questionnaires. Result: The attitude score before the experiment was 4.13, which indicates a neutral attitude, Nursing students' attitudes toward the elderly related significantly to religion, living with grandparents, volunteer work for the elderly, and acquired knowledge. The Senior simulation enabled nursing students' attitudes to turn positive toward the elderly. Conclusion: Senior simulation can affect nursing students' attitude toward the elderly. There is a need to develop routine education programs to maintain the positive attitude.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.12 no.3
• /
• pp.213-220
• /
• 2007

As the equipments with the fast load characteristics become popular, a onboard generator should satisfy the fast response characteristics. This paper describes the modeling, simulation and experiment of the homo-polar generator developed for the fast load. The simulation model of a homo-polar generator with input limiter is developed, and the optimal gain to improve the response characteristics can be determined by simulation and analysis. The improved bandwidth and stability of the developed generator with optimal gain are verified by simulation and experiment.

• Journal of the Korean Ceramic Society
• /
• v.46 no.3
• /
• pp.229-233
• /
• 2009

This study has focused on manufacturing technique of powder injection molding of watch case made from zirconia powder. A series of computer simulation process was applied to prediction of the flow pattern in the inside of the mould to clarifying the change of sintering shrinkage depended on flow direction. The material properties of melted feedstock inclusive of the PVT graph and thermal viscosity flowage properties were measured for obtaining the input data in computer simulation. Also, molding experiment was conducted and the results of experiment showed that good agreement with simulation results for flow pattern and weld line location. On the other hand, gravity and inertia effect have an influence on velocity of melt front because of high density of ceramic powder particles in powder injection molding against the polymer injection molding process. In the experiment, the position of melt front was compared with upper gate and lower gate position. The gravity and inertia effect could be confirmed in the experimental results.

• Journal of Power System Engineering
• /
• v.21 no.3
• /
• pp.51-59
• /
• 2017

In the early design stage of underwater vehicles, it is important to estimate the vehicle's underwater motion performance. The key design elements for the motion are propellers, battery power, and underwater resistance of the vehicle. Small thrusters with motor and propeller are usually used for the UUV(unmanned underwater vehicles). In this study, a multiphysics thruster model combining electro-mechanical and hydrodynamics characteristics was proposed to estimate the thruster performance. To show the applicability of the mathematical model, an sample thruster was used for the derive the unknown parameters of thruster. Hydrodynamic parameters were calculated for a 3D geometry model of the propeller by ANSYS/CFX program. Finally, Matlab/simulink program was used for the numerical simulation to predict the thruster performance from the given voltage/current input to the motor. Also, proved validity of simulation model by experiment test. Test were done by 2 mode(middle/high speed, reverse). The thruster performance curves obtained from this simulation were confirmed to be similar with experiment results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.1
• /
• pp.35-44
• /
• 2010

Available daylight in inside offers comfortable view environment, and psychological and physical advantages to people in a room. Architectural design has a need for daylight prediction. But it is difficult to predict the illuminance values in daylight system. Using various Daylight simulation software is easy and simple, but we can find different results under the same conditions. This study compares with illuminance values from simulation (Lightscape 3.2, Relux 2007, Radiance 3.9) and Mock-up experiment with a same space and parameter of daylight (location of space and window, date, time and sky condition).

• International Journal of Fluid Machinery and Systems
• /
• v.2 no.4
• /
• pp.303-314
• /
• 2009

The present paper shows the results of numerical and experimental modal analyses of Francis runners, which were executed in air and in still water. In its first part this paper is focused on the numerical prediction of the model parameters by means of FEM and the validation of the FEM method. Influences of different geometries on modal parameters and frequency reduction ratio (FRR), which is the ratio of the natural frequencies in water and the corresponding natural frequencies in air, are investigated for two different runners, one prototype and one model runner. The results of the analyses indicate very good agreement between experiment and simulation. Particularly the frequency reduction ratios derived from simulation are found to agree very well with the values derived from experiment. In order to identify sensitivity of the structural properties several parameters such as material properties, different model scale and different hub geometries are numerically investigated. In its second part, a harmonic response analysis is shown for a Francis runner by applying the time dependent pressure distribution resulting from an unsteady CFD simulation to the mechanical structure. Thus, the data gained by modern CFD simulation are being fully utilized for the structural design based on life time analysis. With this new approach a more precise prediction of turbine loading and its effect on turbine life cycle is possible allowing better turbine designs to be developed.

• Journal of Internet Computing and Services
• /
• v.21 no.5
• /
• pp.97-107
• /
• 2020

This paper introduces an online experiment environment based on a computational science platform that can be used for various purposes ranging from basic education to quantum chemistry and professional quantum chemistry research. The simulation environment was constructed using a simulation workbench and simulation workflow, which are execution environment services of Science App provided by the computational science platform. We developed an environment in which learners can learn independently without an instructor by selecting experiment topics that can be used in various areas of chemistry, and offering the learning materials of the topics in a form of e-learning content that includes theory and simulation exercises. To verify the superiority of the proposed system, it was compared with WebMO, a state-of-the-art web-based quantum chemistry simulation service.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.41 no.3
• /
• pp.219-227
• /
• 2021

Numerical simulation with Hwang's scheme, which can analyze shallow-water flow over discontinuous topography, was compared with a laboratory experiment of flooding on a perpendicular floodplain with dam-break flows. The simulation results were in good agreement with the results measured in an experimental flume with a reservoir, channel, and floodplain. The wetting and drying process on a perpendicular floodplain with a dam-break flow was particularly well simulated. The difference in simulation results according to the type of flow resistance was insignificant. The results of this study are expected to improve the accuracy of predicting inundation in urban rivers.