• Journal of Digital Convergence
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• v.16 no.6
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• pp.197-204
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• 2018

The realistic Visual Effects using fluid simulation in 3D computer graphics are operated as important factors to improve the quality of images. The process of creating realistic motions of water, fire, explosion by controlling each property of fluid is called fluid simulation. In general, the creation of a fluid simulation concentrates on the main simulation work phase, however an effective method for initial set up is important for the main simulation work. The purpose of this study is to analyze the factors involved in the initial emission motion and shape of fluid and propose methods that can efficiently apply this into the initial set up. For the process of the research, first, problems are raised based on related researches, and second, two experiments, 'Dynamic Fluid Emitter Creation' and 'User Design Type Emission Velocity Solution', are conducted for more effective fluid simulation. Through this research, the effective fluid simulation of initial set up phase will be suggested through the user design-type emission control solutions.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.54.3-54
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• 2001

This paper presents a controller design technique for standard 2nd-order system satisfying user-specified phase margin. A simple method is presented to meet stability margin for the 2nd-order system, which is important since the 2nd-order plant models are frequently encountered in the practical plant models such as actuators of the optical drive systems. Through the comparison of the specified stability margin and achieved stability margin, it is shown in the simple example that the proposed technique is useful in the initial design of control systems with stability margin specifications.

• Journal of The Korean Digital Architecture Interior Association
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• v.11 no.4
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• pp.29-38
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• 2011

In this study, neighborhood facility and office building to target two cases were performed BIM process. In the initial design phase of the planning process was conducted for the BIM process modeling, BIM in the design stage while performing the required range and level of the process were studied. Accordingly, from architectural firms to leverage BIM process, the proposed methods, efficient use of the modeling process proposed. Quality management information and input for the modeling and design process should be determined from the initial design and construction, including, for each field should be considered BIM, which require an appropriate range of information, according to these requirements, BIM creation and expansion of the level of information should be clearly defined. Perform the procedure for BIM in the process of communicating with stakeholders is critical. In addition, the input data and output data needed to perform management and to perform at the level obtained BIM design process and the model should be clear.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.1
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• pp.17-22
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• 2017

In this study, we designed the metallic reception part of a patch antenna using the phase field design method. The design object function is formulated with the S-parameter value which represent the return loss so that it is targeted to maximize radiation efficiency at a target frequency. The initial model of a patch antenna was designed via the ordinary theory based approach and its performance was enhanced by changing the structural configuration of the metallic part using the phase field design method combined with the double well potential functions. The final shape was proposed by removing the gray scale area along the structural boundary by employing a cut-off method. The proposed shape shows that the radiation efficiency at target frequency is significantly improved compared with the initial patch shape. The finite element analysis and optimization precess was performed using the commercial package COMSOL and Matlab programming.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1099-1102
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• 1996

In this paper, roll/yaw attitude control of spacecraft using a double gimbaled wheel is discussed with two feedback controllers designed. One is a PD controller with no phase difference between roll and yaw control input. The other is a PD controller with a phase lag compensator about the yaw control input. The phase lag compensator is designed as a first order system and a lag parameter is designed for the yaw angle control. There are two case simulations for each controller ; constant disturbance torques and initial errors of nutation at motion. We obtain the results through simulations that steady-state error and rising time of yaw angle are determined by the compensator. Simulation parameters used in this study are the values of KOREASAT F1.

• Korean Journal of Computational Design and Engineering
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• v.18 no.5
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• pp.338-347
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• 2013

Since it is common that design BIM data created by designers and engineers do not afford to consider constructability for the site, it is usually necessary to optimize the design BIM data to construction BIM data. While this optimization process requires various design updates depending on the construction methods and requirements, most designers in the projects do not participate the construction phase, which can arise another obstacle factor in utilizing construction BIM. In order to prevent this issue, we need cooperation system, where all the parties work together from the initial stage of project to create quality assured BIM model. However this kind of system is not realistic in Korea with most of the working processes being conventional yet. Therefore, at this point of time, it is realistic for us to secure basic construction qualities in the design phase and keep those qualities by the construction phase. This study suggested a relevant quality management plan for BIM usage in construction phase.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1085-1086
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• 2011

This paper proposes a structure optimal design of 2-phase BLDC motor. In order to improve the characteristics of the BLDC motor such as the efficiency, average torque, the Kriging method and genetic algorithm are utilized. In addition, the result of the optimal model were compared with the initial model and verified by 2D FEM.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1999.11a
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• pp.181-183
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• 1999

This paper is about the design of half-bridge inverter controller with low cost and simple configuration for low power single-phase induction motor driving. The simple controller is composed of MCU and PLD. Also, to limit the overcurrent at initial driving, auxiliary function is added, and stabilizes the system. In order to verify the performance of the proposed methode, we design 500W inverter system, and in result, the response time of the proposed method compared with line voltage driving method is reduced by 200[msec].

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.11
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• pp.1528-1534
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• 2013

This paper proposes the optimal design of stator shape for cogging torque reduction of single-phase brushless DC (BLDC) motor with asymmetric notch. This method applied size and position of asymmetric notches to tapered teeth of stator for single-phase BLDC motor. Which affects the variation of the residual flux density of the permanent magnet. The process of optimal design included the extraction of the sampling point by using Latin Hypercube Sampling(LHS), and involved the creation of an approximation model by using kriging method. Also, the optimum point of the design variables were discovered by using the Genetic Algorithm(GA). Finite element analysis was used to calculate the characteristics analysis and cogging torque. As a result of finite element analysis, cogging torque were reduced approximately 39.2% lower than initial model. Also experimental result were approximately 38.5% lower than initial model. The period and magnitude of the cogging torque were similar to the results of FEA.

• Structural Engineering and Mechanics
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• v.69 no.2
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• pp.121-129
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• 2019

The present study investigates the propagation of shear waves in a composite structure comprised of imperfectly bonded piezoelectric layer with a micropolar half space. Piezoelectric layer is considered to be initially stressed. Micropolar theory of elasticity has been employed which is most suitable to explain the size effects on small length scale. The general dispersion equations for the existence of waves in the coupled structure are obtained analytically in the closed form. Some particular cases have been discussed and in one particular case the dispersion relation is in well agreement to the classical-Love wave equation. The effects of various parameters viz. initial stress, interfacial imperfection and micropolarity on the phase velocity are obtained for electrically open and mechanically free system. Numerical computations are carried out and results are depicted graphically to illustrate the utility of the problem. The phase velocity of the shear waves is found to be influenced by initial stress, interface imperfection and the presence of micropolarity in the elastic half space. The theoretical results obtained are useful for the design of high performance surface acoustic devices.