• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.10-24
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• 2013

The state-of-arts of multiscale simulation (MSS) in science and engineering is briefly presented and MSS for process development (PD-MSS) is proposed to effectively apply the MSS to the process development. The four-level PD-MSS is composed of PLS (process-level simulation), FLS (fluid-level simulation), mFLS (microfluid-level simulation) and MLS (molecular-level simulation). Characteristics and methods of each level, as well as connectivity between the four levels are described. For example in PD-MSS, absorption column, fluidized-bed reactor, and adsorption process are introduced. For successful MSS, it is necessary to understand the multiscale nature in chemical engineering problems, to develop models representing physical phenomena at each scale and between scales, to develop softwares implementing mathematical models on computer, and to have strong computing facilities. MSS should be performed within acceptable accuracy of simulation results, available computation capacity, and reasonable efficiency of calculation. Macroscopic and microscopic scale simulations have been developed relatively well but mesoscale simulation shows a bottleneck in MSS. Therefore, advances on mesoscale models and simulation tools are required to accurately and reliably predict physical phenomena. PD-MSS will find its way into a sustainable technology being able to shorten the duration and to reduce the cost for process development.

• Journal of Powder Materials
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• v.5 no.4
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• pp.324-328
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• 1998

This paper is aimed to study the computer simulation of sintering process for ceramics by Monte Carlo and molecular dynamics methods. Plural mechanisms of mass transfer were designed in the MC simulation of sintering process for micron size particles; the transfer of pore lattices for shrinkage and the transfer of solid lattices for grain growth ran in the calculation arrays. The MD simulation was performed in the case of nano size particles of ionic ceramics and showed the characteristic features in sintering process at atomic levels. The MC and MD simulations for sintering process are useful for microstructural design for ceramics.

• Journal of the Korea Society for Simulation
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• v.8 no.1
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• pp.19-33
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• 1999

The fundamental issues to evaluate machine tools performance through simulation pertain to the physical models of the machine tool itself and of process while the practical problems are related to the development of the modular software structure. It allows the composition of arbitrary machine/process models along with the development of programs to evaluate each state of machining process. Surface roughness is one of the fundamental factors to evaluate machining process and performance of machine tool, but it is not easy to evaluate surface roughness due to its tribological complexity. This paper presents an algorithm to calculate surface roughness considering cutting geometry, cutting parameters, and contact dynamics of cutting between tool and workpiece as well as tool wear in turning process. This proposed algorithm could be used in the designed virtual machining system. The system can be used to evaluate the surface integrity of a turned surface during the design and process planning phase for the design for manufacturability analysis of the concurrent engineering.

• Transactions of Materials Processing
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• v.21 no.5
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• pp.298-304
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• 2012

The shielded slot plates for a molten carbonate fuel cell(MCFC) have a sheared corrugated trapezoidal pattern. In the FEM simulations for the production of the shielded slot plate, the user material subroutine VUMAT in the commercial FEM software ABAQUS was used to implement a ductile fracture criterion. The critical damage value for the ductile fracture criterion was determined by comparing the experimental results of the shearing process with the simulation results. Using the ductile fracture criterion, the FEM simulation of the three-dimensional forming process of the shielded slot plate was conducted. The effects of the shearing process on the forming process were examined through FEM simulation and experiments. The forming simulation of nine unit cells was conducted. Using the simulation results of the forming process, the deformed shape after springback was calculated. The experimental result shows good agreement with the simulation.

• Proceedings of the Korea Society for Simulation Conference
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• 2003.11a
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• pp.185-192
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• 2003

Digital Manufacturing-based production could be very effective in shipbuilding in order to save costs and time, to increase safety for workers, and to prevent bottleneck processes in advance. Digital shipbuilding system, a simulation-based production tool, is being developed to achieve such aspects in Korea. To simulate material flow in a subassembly line at a shipyard, the product, process and resources was modeled for the subassembly process which consisted of several sub-processes such as tack welding, piece alignment, tack welding, and robot welding processes. The analysis and modeling were carried out by using the UML(Unified Modeling Language), an object-oriented modeling method as well as IDEF(Integration DEFinition), a functional modeling tool. Initially, the characteristics of the shop resources were analyzed using the shipyard data, and the layout of the subassembly line was designed with the resources. The production process modeling of the subassembly lines was performed using the discrete event simulation method. Using the constructed resource and process model, the productivity and efficiency of the line were investigated. The number of workers and the variations In the resource performance such as that of a new welding robot were examined to simulate the changes in productivity. The bottleneck process floated according to the performance of the new resources. The proposed model was viewed three-dimensionally in a digital environment so that interferences among objects and space allocations for the resources could be easily investigated

• Korean Journal of Computational Design and Engineering
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• v.16 no.6
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• pp.449-457
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• 2011

The productivity improvement is indispensible to shipbuilding industry for maintaining the world's No. 1. Simulation based production recently has been an issue as prat of efforts to high efficiency production and Korean shipyards requests simulation system tools specialized in a shipbuilding industry. IT convergence project between conventional shipbuilding industry and IT simulation technology has been carried out and integrated simulation framework was proposed as a way to overcome sporadic developments. The framework would provide reusability of kernels and modules and also ensure for expansibilities to other production simulations. The fact that production simulation system should reflect shipyard requirement would be most important. We suggest an analysis process of customer requirements and functional requirements for production simulations. It is partially based on concepts of software engineering and axiomatic design. The process is applied to a design of configuration for simulation framework.

• IE interfaces
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• v.18 no.1
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• pp.22-34
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• 2005

This paper introduces a simulation model which is based on the process analysis of a semiconductor company. The objective of the simulation modelis not only to estimate the overall performancesof the company but also to evaluate the performances of various operation rules for shop floor control. First, in order to develop the simulation model, a time study is performed for each process after analyzing the processes for the company. Second, by using ARENA, a simulation model is constructed based on the process analysis and the time study. After the simulation model is tested and run, its results are discussed.

• IE interfaces
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• v.1 no.1
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• pp.27-37
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• 1988

In the multi-stage and multi-process plant, it is not an easy task to describe the interrelationships among each process and facility. The purpose of this simulation study is to analyze the effect of additional facilities on productivity in a steel mill. The simulation was performed using SLAM Simulation Language for Alternative Modeling. The results of this study was used by the plant engineers in making decisions on the expansion of the plate mill. The prediction of which process would cause bottle-necks enabled the plant engineers to invest most effectively.

• The Korean Journal of Health Service Management
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• v.6 no.4
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• pp.245-254
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• 2012

The purpose of this study was to approve the effects of nursing simulation-based education on problem solving process and self-efficacy for nursing students. The nursing students of 244 participated the nursing simulation-based education of 60 hours. The questionnaire survey on problem solving process and self-efficacy were conducted 2 time(before education, after education) to the nursing students. The data were analyzed by the SPSS 12.0 program. The results were as follows; There was a statistically significant increase in problem solving process(t=2.637, p=.012) but no statistically significants self-efficacy(t=0.135, p=.743) effects of nursing simulation-based training in nursing college students. There was a significant positive correlation between problem solving process and self-efficacy(r=0.737, p=.017). In conclusion, the study found that nursing simulation-based education for nursing students may increase problem solving process but no effective self-efficacy.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.11
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• pp.114-123
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• 1996

The major objective of the present paper is to estabilish analytical technique in order to closely understand and analyze the actual shearing process. First of all, isothermal and non-isothermal FE-simulation of the shearing process are carried out using finite element software DEFORM. Based on preliminary simulation using DEFORM, the finite element program to analyze two dimensional shearing process is developed. The ductile fracture criterion and the element kill method are also used to estimate if and where a fracture will occur and to investigate the features of the sheared surface in shearing process. It can be seen that the developed program combined with the ductile fracture criterion and element kill method has enabled the achievement of FE-simulation from initial stage to final stage of shearing process. The effects of punch-die clearance on shearing process are also investigated. In order to verify the effectiveness of the proposed technique the simulation results are compared with the known expermental data. It is found that the results of the present work are in close agreement with the published experimental results.