• Journal of Korean Society of Transportation
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• v.29 no.1
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• pp.113-123
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• 2011

The application of micro-simulation model has been extended farther with improvement of computer performance and development of complicated model. To make a micro-simulation model accurately replicate field traffic conditions, model calibration is very crucial. Studies on calibration of micro-simulation model have not been enough while lots of studies on calibration of macro-simulation model have been continued in our country. This paper presents an auto-calibration of parameter values in micro-simulation model(VISSIM) using genetic algorithm. RMSE(Root Mean Square Error) of collected volume on the urban expressway versus simulated volume is set as MOP(measure of performance) and objective function of optimization is set as to minimize the RMSE. Applying to urban expressway(Nae-bu circular) as a case study, it shows that RMSE of optimized parameter values decrease 60.4%($19.3{\longrightarrow}7.6$) compared to default parameter values and the proposed auto-calibration system is very effective.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.457-464
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• 2007

Micro-Grid comprising Micro-Sources supplying several $kW{\sim}MW$ power to local customers is environmentally friendly and reliable. This paper deals with the development of simulation models of Micro-Grid on the PSCAD/EMTDC platform for analyzing various aspects of the interaction of the Micro-Grid. The developed switching level model adopts the space vector PWM. Both switching level and power frequency Micro-Source models are developed, which shows that power frequency modeling is sufficient for analyzing the phenomena of interest. Control characteristics of the Micro-Sources with the parameter and load power variation are analyzed for power quality enhancement. The simulation results show that the developed models are effective for studying Micro-Grid.

• Smart Structures and Systems
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• v.22 no.6
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• pp.643-662
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• 2018

One of the methods for investigation of mechanical behavior of materials is numerical simulation. For simulation, its need to model behavior is close to real condition. PFC is one of the rock mechanics software that needs calibration for models simulation. The calibration was performed based on simulation of unconfined compression test and Brazilian test. Indeed the micro parameter of models change so that the UCS and Brazilian test results in numerical simulation be close to experimental one. In this paper, the effect of four micro parameters has been investigated on the uniaxial compression test and Brazilian test. These micro parameters are friction angle, Accumulation factor, expansion coefficient and disc distance. The results show that these micro parameters affect the failure pattern in UCS and Brazilian test. Also compressive strength and tensile strength are controlled by failure pattern.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.520-521
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• 2008

This paper deals with simulation model of the micro-grid system based on the real power system and applying PV generation system to micro-grid system. PSCAD/EMTDC simulation model is developed for use in studying the effect of the dynamics of PV generation to the micro-grid system. Simulation results show that the addition of the PV system improves the voltage profile of the area. Case studies also show that power quality at the load side is improved via voltage compensation at the load bus.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.10
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• pp.1394-1405
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• 2002

The performance of micro-actuators utilizing radiometric forces are studied numerically. The Knudsen number based on gas density and characteristic dimension is varied from near-continuum to highly rarefied conditions. Direct simulation Monte Carlo(DSMC) calculations have been performed to estimate the performance of the micro-actuators. In the present DSMC method, the variable hard sphere molecular model and no time counter technique are used to simulate the molecular collision kinetics. For simulation of diatomic gas flows, the Borgnakke-Larsen phenomenological model is adopted to redistribute the translational and internal energies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.4
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• pp.233-239
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• 2002

The technology of joining BT (Biotechnology) with NT (Nanotechnology) must be rapidly arranged in 21c. Specially, the technical value is important more and more since the research about MEMS, which synthesizes BT and NT, is variously proceeding on the wide fields. This study by simulation shows the Fluid-Flow within micro Pump used in Bio-MEMS technology through Fluent Program. Namely, this experiment shows the most suitable external conditions and Pump Model within micro Pump by observing the flow of fluids as to the conditions of pressure, temperature and Model when the Fluid flows within micro Pump. We saw the variousness of pressure and temperature as to the existence of Chamber through examining by reference of Fluid-Flow. In the case of the existence of Chamber, the variousness of pressure and temperature is less than in the case of the non-existence of Chamber. By this simulation, we know that the Pump, which has a Chamber, affects the Fluid-Flow less than that. So we can say that it is necessary for us to design the Pump which has a Chamber.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.2
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• pp.78-83
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• 2007

In this paper, the digital model of the micro-factory has been established, inspected and evaluated by progress of assembly, manipulation and examination. The new paradigm of the system analysis is realized by digital simulation of the factory. The digital manufacturing system of the micro-factory was simulated through UML(Unified Modeling Language) with the object-oriented logical model analysis method and then the micro lens module assembly system was simulated with MST(Micro System Technology) Application Module.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.1
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• pp.121-126
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• 2016

Hydraulic performance of a micro-bubble pump has been analyzed by numerical simulation and experimental measurements. Flow recirculation apparatus between the pump inlet and outlet reserviors has been adopted to measure pump performance according to flow conditions sequentially. To analyze three-dimensional flow field in the micro-bubble pump, general analysis code, CFX, is employed. SST turbulence model is employed to estimate the eddy viscosity and compared the pump performance to k-${\varepsilon}$ model. Unstructured grids are used to represent a composite grid system including blade, casing and inlet casing. It is found that the numerical model used in the present study is effective to evaluate the pump performance. From the numerical simulation, low velocity region due to pressure loss is decreased where pump efficiency has maximum value. Detailed flow field inside the micro-bubble pump is also analyzed and compared.

• Journal of Power Electronics
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• v.11 no.3
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• pp.350-359
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• 2011

This paper describes the operational analysis results of a DC micro-grid using a detailed model of distributed generation. A detailed model of wind power generation, photo-voltaic generation and fuel cell generation was implemented with an userdefined model created with PSCAD/EMTDC software and coded in C-language. The operational analysis was carried out using PSCAD/EMTDC software, in which the power circuit is implemented by a built-in model and the controller is modeled by an user-defined model that is also coded in C-language. Various simulation results confirm that a DC micro-grid can operate without any problems in both the grid-tied mode and in the islanded mode. The operational analysis results confirm that the DC micro-grid makes it feasible to provide power to the load stably. It can also be utilized to develop an actual system design.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1115-1117
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• 2005

This paper describes the three dimension model and simulation results of a thermal actuator based on polyMUMPs process, known as thermal multimorph actuator. The device has potential application in micro-transducers such as atomic force microscope (AFM) tip and scanning tunneling microscope (STM) tip. This device made of a multi-layer materials stack together with consisted of polysilicon, $SiO_2$ and gold. A mask layout design, three dimension model and simulation results are reported and discussed.