• 디지털융복합연구
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• 제16권6호
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• pp.197-204
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• 2018

3D 컴퓨터그래픽에서 유체를 이용한 사실적인 시각효과(Visual Effects)는 영상의 질적 완성도를 높이는데 중요한 요소로 작용한다. 유체의 각 속성을 제어하여 물, 불, 폭발 등의 사실적인 움직임을 생성시키는 과정을 유체 시뮬레이션(Fluid Simulation)이라 한다. 일반적으로 유체 시뮬레이션의 제작은 주 시뮬레이션(Main simulation) 작업단계에 집중되지만, 이를 위한 사전준비 단계(Initial set up)인 초기 방출자에 대한 효과적인 생성방법이 중요하다. 이에 본 연구의 목적은 유체의 초기 방출 운동과 형태에 관여하는 요소들을 분석하고 이를 초기 제작공정에 적용할 수 있는 효과적인 방법을 제시하고자 한다. 이를 위한 연구의 전개는 첫째, 기존 관련 연구에 대해 분석 및 문제점을 제기하고, 둘째, 보다 효과적인 유체효과 시뮬레이션 진행을 위해, Dynamic Fluid Emitter Creation과 User Design Type Emission Velocity Solution에 대한 두가지 실험을 진행한다. 본 연구를 통해, 사용자 설계형의 방출 제어 솔루션을 통해 효율적인 초기단계의 유체 시뮬레이션 제작방법을 제시한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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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.

• 한국디지털건축인테리어학회논문집
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• 제11권4호
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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.

• 한국전산구조공학회논문집
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• 제30권1호
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• pp.17-22
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• 2017

본 연구에서는 페이즈필드 설계법에 기반한 형상최적설계를 통해 개선된 패치안테나 금속 패치 부분의 형상 설계를 진행하였다. 설계 목적은 패치 안테나의 목적 주파수에서의 방사 효율을 최대화 하는 것으로 설정하였고, 이에 따라 목적 함수는 반사손실을 나타내는 S-파라미터 값의 최소화로 정의하였다. 패치형상의 최적화 결과는 페이즈필드 설계법을 이용하여 도출하였고, 최적화 결과의 회색영역을 제거하기 위해서 컷오프 방법을 적용하였다. 더불어 쿼터 정합기의 길이 변화를 통해 성능 개선 과정을 진행하였다. 이를 통해 도출해낸 최종 형상에 대한 해석 결과, 목표 주파수에서의 S-파라미터 값이 -1.14dB에서 -12.73dB로 개선됨을 확인하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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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.

• 한국CDE학회논문집
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• 제18권5호
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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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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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.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1999년도 학술대회논문집-국제 전기방전 및 플라즈마 심포지엄 Proceedings of 1999 KIIEE Annual Conference-International Symposium of Electrical Discharge and Plasma
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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].

• 전기학회논문지
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• 제62권11호
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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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• 제69권2호
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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.