• Journal of Ocean Engineering and Technology
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• v.20 no.4 s.71
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• pp.76-82
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• 2006

The large-eddy simulation(LES) technique, based an a message passing interface method(MPI), was applied to investigate the turbulent flaw phenomena around a ship. The Smagorinski model was used in the present LES simulation to simulate the turbulent flaw around a ship. The SPMD(sidsngle program multiple data) technique was used for parallelization of the program using MPI. All computations were performed an a 24-node PC cluster parallel machine, composed of 2.6 GHz CPU, which had been installed in the Advanced Ship Engineering Research Center(ASERC). Numerical simulations were performed for the Wigley hull, and the Series 60 hull(CB=0.6) using 1/4-, 1/2-, 1- and 2-million grid systems and the computational results had been compared to the experimental ones.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.395-402
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• 2005

This paper deals with modeling and computer simulation of a full multibody vehicle model for a driving simulator. The multibody vehicle model is based on the recursive formulation and a corresponding simulation code is generated automatically from AUTOCODE, which is a symbolic computation package developed by the authors using MAPLE. The paper describes a procedure for automatically generating a highly efficient simulation code for the full vehicle model, while incorporating realistically modeled components. The following issues have been accounted for in the procedure, including software design for representing a mechanical system in symbolic form as a set of computer data objects, a multibody formulation for systems with various types of connections between bodies, automatic manipulation of symbolic expressions in the multibody formulation, interface design for allowing users to describe unconventional force-and torque-producing components, and a method for accommodating external computer subroutines that may have already been developed. The effectiveness and efficiency of the proposed method have been demonstrated by the simulation code developed and implemented for driving simulation.

• Korean Management Science Review
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• v.11 no.1
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• pp.1-21
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• 1994

We usually use the simulation technique in the evaluation and the test of a design alternative of Automated Guided Vehicle System. In this paper, we introduce a simulation code generator which can assist simulation programmer in model development and programming. It consists of user interface, program editor, and program sorter. SIMAN is used as the target language.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.6
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• pp.124-136
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• 2002

A freshwater lake water quality management system(FLAQUM) was developed to help regional manager for the water quality of a rural basin. The integrated user interface system FLAQUM written in Visual Basic, includes three subsystems such as a database management system, basin pollutant loads simulation model using SWMM model and freshwater lake water quality simulation model using WASP5 model. Pollutant load simulation model was applied to simulate the discharge and pollutant loading from the watershed, and freshwater lake water quality model was applied to analyze the changes in water quality with respect to watershed pollutant loads, and this model could be used in planning to control watershed pollutant source for water quality management. Database management system was constructed fur all input and output data processing, and it can be used to analyze statistical characteristics using constructed data. Results are displayed both graph and text for convenience of user. The results of FLAQUM application to Boryeong freshwater lake showed that the lake was in eutrophic condition. The major contribution of pollution comes from tributary No.1 and No.4, which have a large number of livestock farms. Therefore, water quality management must be focused on appropriate management of the livestock farming in the two breanchs.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.6
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• pp.615-622
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• 2010

In this study, a 0D multizone spray-combustion model is developed for the estimation of the performance and NOx emission of medium-sized direct-injection marine diesel engine. The developed combustion model is coupled with the commercial 1D cycle-simulation model, Boost, to analyze the entire engine system, including the intake and exhaust. The combustion model code was generated using Fortran90, and the model was coupled with Boost by connecting the generated code to a user-defined high-pressure cycle (UDHPC) interface. Simulation was performed for two injectors (8 holes and 10 holes) and two engine loads (50% and 100%), and the results of simulation were in good agreement with engine performance test.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.5
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• pp.530-537
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• 2013

An explicit surface potential calculation method of gate-all-around MOSFET (GAAMOSFET) devices which takes into account both interface trap charge and varying doping levels is presented. The results of the method are extensively verified by numerical simulation. Results from the model are used to find qualitative and quantitative effect of interface trap charge on subthreshold slope (SS) of GAAMOSFET devices. Further, design constraints of GAAMOSFET devices with emphasis on the effect of interface trap charge on device SS performance are investigated.

• Structural Engineering and Mechanics
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• v.41 no.5
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• pp.645-662
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• 2012

Deteriorative effects of steel corrosion on the structural response of reinforced concrete are simulated for varying degrees of corrosion. The simulation approach is based on a three-dimensional irregular lattice model of the bulk concrete, in which fracture is modeled using a crack band approach that conserves fracture energy. Frame elements and bond link elements represent the reinforcing steel and its interface with the concrete, respectively. Polylinear stress-slip properties of the link elements are determined, for several degrees of corrosion, through comparisons with direct pullout tests reported in the literature. The link properties are then used for the lattice modeling of reinforced concrete beams with similar degrees of corrosion of the main reinforcing steel. The model is successful in simulating several important effects of steel corrosion, including increased deflections, changes in flexural cracking behavior, and reduced yield load of the beam specimens.

• Journal of the Korea Society for Simulation
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• v.24 no.1
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• pp.25-34
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• 2015

It is necessary for us to undergo trial and error for eliciting the rational requirement of the acquisition of weapon systems, but the M&S is general approach due to costs and risk of the development. In addition to the acquisition of weapon systems, M&S is extensively employed in the analysis and the training of developed weapon systems. The ADD (Agency for Defense Development) has developed DEVS integrated development environment (QUEST) that provides M&S general ground technique composed of simulation model implementation services, simulation result analysis services, and simulation interface services. This paper describes the interface architecture and the implementation of torpedo target detection section interface simulation system using QUEST. The torpedo target detection section interface simulation system is composed of torpedo target detection section which calculates a result of target detection and the QUEST scenario generator which provides simulation scenario for performance test of the torpedo target detection section. The interface architecture of torpedo target detection section interface simulation system is designed to verify the interface and performance of the torpedo target detection section by linking with the QUEST scenario generator.

• Tribology and Lubricants
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• v.39 no.1
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• pp.8-12
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• 2023

This study presents a molecular simulation of adhesion control between carbon nanotube (CNT) and Ag thin film deposited on silicon substrate. Rough and flat Ag thin film models were prepared to investigate the effect of surface roughness on adhesion force. Heat treatment was applied to the models to modify the adhesion characteristics of the Ag/CNT interface based on thermal wetting. Simulation results showed that the heat treatment altered the Ag thin film morphology by thermal wetting, causing an increase in contact area of Ag/CNT interface and the adhesion force for both the flat and rough models changed. Despite the increase in contact area, the adhesion force of flat Ag/CNT interface decreased after the heat treatment because of plastic deformation of the Ag thin film. The result suggests that internal stress of the CNT induced by the substrate deformation contributes in reduction of adhesion. Contrarily, heat treatment to the rough model increases adhesion force because of the expanded contact area. The contact area is speculated to be more influential to the adhesion force rather than the internal stress of the CNT on the rough Ag thin film, because the CNT on the rough model contains internal stress regardless of the heat treatment. Therefore, as demonstrated by simulation results, the heat treatment can prevent delamination or wear of CNT coating on a rough metallic substrate by thermal wetting phenomena.

• Proceedings of the Korea Society for Simulation Conference
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• 2002.11a
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• pp.85-89
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• 2002

Development of distributed simulation environment must be required in order to simulate the distributed models regionally and inter-operate with running simulations individually, Simulation based on DEVS formalism is difficult to simulate the distributed models. DEVS formalism is modeling methodology. To specify model, this formalism separates behavior and structure, therefore it is able to design complex model easily. HLA is standard framework of distribute simulation environment, It is defined to facilitate the interoperability and the reusability. RTI (Run Time Infrastructure) is software that provides common service to simulation systems and implementation of the HLA Interface Specification. Method of implementation is that modules cooperating with RTI are added to simulator on DEVS simulation environment. On the DEVS simulation environment (DEVS-Obj -C) that already developed, Highest class of abstract simulator uses service that RTI provide, then This environment is able to change DEVS model into Federate and run distribute simulation that inter-operates with the RTI. Because this distributed simulation environment includes convenience of modeling that obtains through the DEVS formalism and accompanies HLA standard, this environment make it possible to simulate with_ complex systems and heterogeneous simulations