• IE interfaces
• /
• v.16 no.2
• /
• pp.258-267
• /
• 2003

Recently, virtual reality technologies have been rapidly developed and realtime virtual simulation methods have been extensively employed for several application areas such as game, sports, manufacturing, military, and so on. A 3D database in realtime virtual simulation plays a key role because it makes users feel reality in virtual space. In a application view of 3D database, a systematic construction approach is required to reduce its construction time and increase its quality. However, many researches have been mostly focused on realtime graphic issues and its key technologies. In virtual simulation of transportation equipments, this paper proposes a systematic construction process of 3D database consisting of four stages as follows: 1) determine the activity space of a equipment, 2) collect data related to 3D database construction, 3) make a 3-dimensional modeling strategy, and 4) generate and evaluate a 3D model. This paper also introduces a new procedure of 3D environment modeling, which summarizes and expands our modeling experiences, to be used as a modeling guide.

• Journal of Korean Society on Water Environment
• /
• v.25 no.5
• /
• pp.651-660
• /
• 2009

Detailed flow analysis in river is essential to increase the accuracy of water quality simulation since flow variation depends on many factors such as cross sections, channel slopes, and bed materials. In the QUAL2E stream water quality simulation model, the hydraulic coefficients are assigned to the reach that is collection of computational element using the hydraulic coefficient. This study developed a module that can incorporate the results of non-uniform flow analysis and assign such information to each individual element. Model application focused on the upstream of the Hoengseong reservoir including the reservoir where significant flow change is expected. Comparing with original QUAL2E model the developed module improved the result of water quality simulation without considering the relation of flow velocity and flow depth in terms of flow rates.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2009.05a
• /
• pp.94-97
• /
• 2009

Cast defect in large steel ingots are estimated in quality and compared each other cast conditions on simulation results by now. The cast defects, micro-crack, shrinkage, pin hole which are predictable in simulation with a reasonable accuracy. In this study, 15 ton steel ingot casting was simulated for solidification model and cast defect prediction. And the real cast was carried out in a foundry for the compeer to the simulation results, the cast defect prediction. Also, the quantity of predicted defect was tried to measuring with the defect mach counting for the various simulated cast conditions. The defect quantity work was used to find the optimized cast condition in DOE(design of experiment) procedure.

• Journal of Electrical Engineering and Technology
• /
• v.8 no.4
• /
• pp.780-786
• /
• 2013

In the reliability-based design optimization of electromagnetic devices, the accurate and efficient reliability assessment method is very essential. The first-order sensitivity-assisted Monte Carlo Simulation is proposed in the former research. In order to improve its accuracy for wide application, in this paper, the second-order sensitivity analysis is presented by using the hybrid direct differentiation-adjoint variable method incorporated with the finite element method. By combining the second-order sensitivity with the Monte Carlo Simulation method, the second-order sensitivity-assisted Monte Carlo Simulation algorithm is proposed to implement reliability calculation. Through application to one superconductor magnetic energy storage system, its accuracy is validated by comparing calculation results with other methods.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.24 no.6
• /
• pp.449-457
• /
• 2011

Effect of pump combinations on the vacuum characteristics of vacuum system was simulated for optimum design of system. In this investigation, the feasibility of modelling mechanism for VacSimMulti simulator was proposed. Simulation results of various pumping combinations showed the possibilities and reliabilities of simulation for the performance of vacuum system in specific semiconductor processing. Simulation of roughing pump presented the expected pumping behaviors based on commercial specifications of employed pumps. Application of booster pump exhibited the high pumping efficiency for middle vacuum range. Combinations of optimum backing pump for diffusion and turbo vacuum system were obtained. And, the predictable characteristics of process application of both simulated systems were also acquired.

• Journal of the Korea Society for Simulation
• /
• v.1 no.1
• /
• pp.87-102
• /
• 1992

This paper presents the development of event-driven system level simulation tool SMPLE(Smpl Extende, an extention fo smpl) and its application to the performance analysis of multiprocessor computer systems. Because of its data structure, it is very difficult to change, expand or add new functions to simulation language smpl implemented by MacDougall. In SMPLE, we change data structure with structure and pointer, add new functions, and enable dynamic memory management. Using new data structure, facilities, and functions added in SMPLE, we simulate job processing of a shared bus multiprocessor system with autonomous hierarchical I/O subsystem. We set system performance contribution of subsystems and units. The impact of disk I/O on system performance is evaluated under vairous conditions of number of processors, processing power, memory access time and disk seek time.

• Proceedings of the Korea Society for Simulation Conference
• /
• 1992.10a
• /
• pp.6-6
• /
• 1992

This work deals with nonlinear least squares method for estimating unknown universial constants C in a computer simulation code real experimental data(or database) and computer simulation data. The best linear unbiased predictor based on a spatial statistical model is fitted from the computer simulation data. Then nonlinear least squares estimation method is applied to the real data using the fitted prediction model(or simulation predictor) as if it were the true simulation model. An application to the computational nuclear fusion device is presented.

• Journal of Korean Institute of Industrial Engineers
• /
• v.41 no.1
• /
• pp.79-85
• /
• 2015

Modeling and simulation has widely been used in the weapon systems acquisition, the military training, and the warfighting experimentation. A study of the warfighting experimentation had been relatively scarce in comparison to other fields (acquisition, training). The main reasons are 1) reliability of simulation model isn't sufficient and 2) collaboration between professional groups is too difficult. To solve this problem, the application framework of warfighting experimentation for military operations was proposed. And through the framework, the case study about sea fight was fulfilled. This framework provides connectivity between warfighting experimentation and military operations planning procedure. With improved reliability, active application of warfighting experimentation could contribute to fighting capability.

• Transactions of Materials Processing
• /
• v.6 no.3
• /
• pp.233-238
• /
• 1997

The estimation of the forming force required for metal forming process is unavoidable for selecting suitable machine and dimensioning die and punch parts. For this purpose the upper-bound method turns out to be very practical in simple two-dimensional cases under well-known boundary conditions. However, the application of this method for complicated two-or three-dimentional cases is very limited or practically impossible. The modified application of FEM in a manner of applying the upper bound method(the so-called Upper-bound Finite Element Simulation Method) fortunately provides the posibility of getting important information about the forming process in a simple and quick way before realizing the process on the machine. It is expected to function successfully even in three-dimentional cases. The application procedure has been explained for two-dimensional cases and its usefulness shown.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.42
• /
• pp.38-49
• /
• 2000

Two application rates (9 and 18 t/ha) of poultry litter and a recommended rate of commercial fertilizer were studied to determine their effects on nutrient (N and P) losses in surface and subsurface runoff and loadings in soil layers from conventionally-tilled com by the treatments. The model predicted higher sediment losses than observed data from all treatments. The overpredicted sediment losses resulted in overprediction of organic-N and sediment-P losses in surface runoff. Simulated soluble-P losses in surface runoff were close to observed data, while NO3-N losses in surface runoff were underpredicted from all treatments. Observed NO3-N concentrations in leachate at 1.0-m depth from commercial fertilizer treatment were fairly well predicted. But the concentratins were overpredicted from poultry litter treatments due to high simulation of organic-N mineralization simulated by the model.