• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2004년도 한국우주과학회보 제13권2호
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• pp.316-320
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• 2004

This paper describes Ka-band antenna performance analysis of COMS satellite. The key parameters of the antenna system are optimal antenna diameter, feed horn type and horn size, F/D, and the coordinate of offset horns. The paper deals with the method to determine design core parameters of optimal antenna diameter, feed horn type and horn size, F/D, and the coordinate of offset horns, and the performances of design result.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권5호
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• pp.323-330
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• 2004

In this paper, we propose a design method of PID controller using an improved Tabu Search. Tabu Search is improved by neighbor solution creation using Gaussian random distribution and generalized Hermite Biehler Theorem for stable bounds. The range of admissible proportional gains are determined first in closed form. Next the optimal PID gains are selected by improved Tabu Search. The results of Computer simulations represent that the proposed Tabu Search algorithm shows a fast convergence speed and a good control performance.

• Journal of Electrical Engineering and Technology
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• 제9권6호
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• pp.1944-1953
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• 2014

This paper shows the design and control methods of the bidirectional DC-DC converter to generate the proper DC-link voltage of a PMSM drive. Conventionally, because the controllable power of the PWM based voltage source inverter is limited by its DC-link voltage, the DC-DC converter is used for boosted DC-link voltage if the inverter source cannot generate enough operating voltage for the PMSM drive. In this paper, to obtain more utilization of this DC-DC converter, optimal DC-link voltage control for PMSM drive will be explained. First, the process and current path of the DC-DC converter will be illustrated, and a control method of this converter for variable DC-link voltage will then be explained. Finally, an improvement analysis of the optimal DC-link voltage control method, especially on the deadtime effect, will be explained. The DC-DC converter of the proposed control method is verified by the experiments by comparing with the conventional constant voltage control method.

• 게임&엔터테인먼트 논문지
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• 제2권1호
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• pp.35-44
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• 2006

본 연구의 목적은 가상현실 분야의 그림 속으로의 여행 기법(TIP, Tour Into the Picture)을 적용하여 운전자가 원하는 목적지까지의 경로를 실시간으로 도로 전경과 동일한 실사기반 3차원 영상으로 보여줄 수 있는 차량용 3차원 네비게이션 시스템을 개발하는데 있다. 이를 위해 기존의 TIP기법을 보완하였고 사용자의 위치와 현재의 도로 상황을 동시에 고려한 최적 경로 탐색기술 등을 제시하였다. 실험 결과, 실제 도로에서 일정 간격을 두고 촬영한 파노라마 실사 영상에 TIP 기법을 적용하여 가상환경을 구축하고 이들 사이의 부드러운 전이를 통해 사진과 같은 품질의 3차원 영상을 보여주었다. 개발된 시스템은 2차원 네비게이션 모듈을 가지며 최적 경로 탐색 및 도로 상황 예측 기능을 제공한다.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.184-189
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• 2014

This paper presents a multi-objective optimization approach to design rotor slot geometry of three-phase squirrel cage induction machine to achieve NEMA design D torque-speed (T-S) characteristics with high efficiency. The multi-objective Particle Swarm Optimization (MOPSO) algorithm combined with the adaptive response surface method and Latin hypercube sampling strategy is applied to obtain the Pareto optimal designs. In order to demonstrate the validity of the suggested optimal algorithm, an application to rotor slot design of three-phase induction motor is presented.

• 한국소음진동공학회논문집
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• 제15권9호
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• pp.1060-1069
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• 2005

Silencers are engineering devices that are designed to attenuate sound waves propagating in a flowing medium. The muffler type silencer has a series of chambers in parallel or series utilizing the reflection and expansion characteristics of the expansion chambers, sidetubes, branch resonators, and tailpipes to attenuate the sound. To Improve the performance of industrial blower silencer of muffler type which is employed in petrochemical plant, this paper seeks its optimal arrangement of buffs by experimental method and suggests optimal arrangement of buffs. Experimental results show that the optimal one suggested can reduce the noise level as much as 14 dB (or 18 dB(A)) in the laboratory and as much as 4 dB(A) compared to that of the existing silencer on the ground.

• International Journal of Internet, Broadcasting and Communication
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• 제10권2호
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• pp.13-18
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• 2018

Drones are controlled by the remote pilot from the ground stations using the radio control or autonomously following the pre-programmed flight plans. In this paper, we develop a method and an optimal path search system for providing 3D augmented reality flight (ARF) images for safe and efficient flight control of drones. The developed system consisted of the drone, the ground station and user terminals, and the optimal path search server. We use the Dijkstra algorithm to find the optimal path considering the drone information, flight information, environmental information, and flight mission. We generate a 3D augmented reality flight (ARF) image overlaid with the path information as well as the drone information and the flight information on the flight image received from the drone. The ARF image for adjusting the drone is generated by overlaying route information, drone information, flight information, and the like on the image captured by the drone.

• 정보처리학회논문지D
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• 제16D권1호
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• pp.113-122
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• 2009

기존의 패턴 탐사 기법들은 제한된 시간 및 공간영역에서 발생하는 다양한 이동 패턴들 중 단순히 사용자 요구에 적합할 것으로 추정되는 불특정한 빈발 이동 패턴만을 탐사하기 때문에 특정지점들 간의 최적 이동 경로나 정해진 시간 내의 스케줄링 경로 탐색과 같은 복합적인 시간 및 공간 제약 조건을 갖는 최적 이동 패턴을 탐사하는 문제에는 적용하기 어렵다. 이에 본 논문에서는 방대한 이동 객체의 이력 데이터 집합으로부터 복합적인 시간 및 공간 제약을 갖는 최적 이동 패턴을 탐사하는 문제를 보이고, 적용 가능한 위치 기반 서비스로서 최적 이동 경로에 해당하는 패턴을 탐색하기 위한 새로운 패턴 탐사 기법인 STOMP-F를 제안한다. 제안된 기법은 특정한 지점들 사이를 이동한 객체의 패턴들 중 객체가 가장 빈번하게 이동한 경로를 탐색하여 최적 경로로 결정하는 패턴 빈발도를 이용한 탐색 방법으로, 최적 이동 패턴 탐사 과정의 이동 시퀀스 생성 단계에서 객체의 위치 값과 공간영역 간의 위상 관계를 고려하여 이동 객체의 위치 속성에 대한 최하위 수준에서의 공간 일반화를 통해 보다 효율적으로 패턴 탐사를 수행할 수 있다. 제안 방법을 Dijkstra 알고리즘과 $A^*$ 알고리즘을 대상으로 실험 평가한 결과 $A^*$ 알고리즘의 휴리스틱 가중치에 따라 차이는 있으나 연산 처리 시간을 기준으로 타 알고리즘들 보다 효과적임을 알 수 있다.

• Journal of Mechanical Science and Technology
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• 제16권8호
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• pp.1095-1101
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• 2002

The load characteristics of engine main bearing are very important in the design of crankshaft and engine block. The stiffness of crankshaft and block, or the optimal dimension of the bearing can be determined according to the load level. This paper presents the load characteristics of engine main bearing. Two components of the main bearing load are measured during engine firing and motoring. The vertical and horizontal load components are measured by using the dynamic load cell mounted in each main bearing cap bolt. The measured main bearing loads are compared with calculated results by using the statically determinate method. The theoretical results, provided in this study, agreed well with the experimental results. The presented results are very useful for achieving optimal design of engine.

• 센서학회지
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• 제14권6호
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• pp.402-408
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• 2005

This paper describes the optimal design of a multi-layered surface plasmon resonance sensors to meet various specifications and improve some physical parameters. Dip 3 dB bandwidth and depth were chosen as design parameters and the objective function was the norm of the difference between design parameters and target values. The design variables are thicknesses of each layer and to obtain the design parameters, the optical admittance method was employed. The (1+1) evolution strategy was employed as an optimization tool. By applying the proposed optimization procedure to a 3-layered sensor, the optimized design variables considerably improved the 3 dB bandwidth by 4.8 nm and the dip depth by 1.1 dB.