• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.822-826
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• 2008

A linkage mechanism is a device to convert an input motion into a desired output motion. Traditional linkage mechanism designs are based on trial and error approaches so that size or shape changes of an original mechanism often result in improper results. In order to resolve these problems, an improved automatic mechanism synthesis method that determines the linkage type and dimensions by using an optimization method during the synthesis process has been proposed. For the synthesis, a planar linkage is modeled as a set of rigid blocks connected by zero-length translational springs with variable stiffness. In this study, the sizes of rigid blocks were also treated as design variables for more general linkage synthesis. The values of spring stiffness and the size of rigid block yielding a desired output motion at the end-effecter are found by using an optimization method.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제12B권1호
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• pp.13-18
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• 2002

Novel method to calculate flux linkage for 3-D finite element analysis is proposed. It does not require any integral path if the current direction in a coil is known. The flux linkage can be calculated very easily using simple volume based integration. The current direction is calculated based on the recently developed technique by the authors. The novel method for flux linkage calculation is verified by applying to a very complicated deflection yoke coil. The simulation result is compared to the experimental one. From the simulation, it is shown that the proposed method is very accurate and effective to calculate the flux linkage of a coil.

• EDISON SW 활용 경진대회 논문집
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• 제4회(2015년)
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• pp.476-478
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• 2015

This paper deals with synthesis of 4 bar linkage by using optimum design. To design 4 bar linkage, overlay method is proposed and for optimization, genetic algorithm is applied with objective function. The accuracy of this method will be determined by errors between real value and test value. We will use Chebychev spacing to get 3 precision positions of input angles. The output angles will be determined by the function that the designer wants input and output relations to be. It will be applied to example to show the accuracy of this method. The advantages of using this method are that it is fast to get optimal solution and it is simple to use.

• 한국게임학회 논문지
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• 제15권2호
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• pp.83-94
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• 2015

온라인 게임 개발을 위해서는 서버 개발 기술이 중요하다. 왜냐하면 사용자들이 게임을 진행하는 클라이언트가 서버에 종속적으로 구현되기 때문이다. 본 연구는 서버 개발 기술 중 서버가 데이터를 데이터베이스에 저장하고 불러오는 데이터연동 방식을 연구하였다. 서버의 데이터 연동은 장소에 관계없이 게임을 이어서 진행할 수 있는 온라인게임의 특성 때문에 매우 중요한 사항이다. 본 논문에서는 여러 데이터연동 방식을 정의와 함께 제안하며 분류하였다. 제안된 방식들을 사례를 통해 평가하였다. 본 연구를 통해 향후 온라인 게임 서버의 개발 시에 게임의 특징에 맞는 데이터연동 방식을 선택할 수 있을 것으로 기대된다.

• Bulletin of the Korean Chemical Society
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• 제33권1호
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• pp.248-254
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• 2012

During the monolayer assembly of zeolite microcrystals using sonication with stacking (SS) method, the factors that govern the degree of close packing (DCP) between the microcrystals, the rate of attachment (rA) of microcrystals onto the substrate, the degree of coverage (DOC), and the binding strength (BS) between each crystal and the substrate were investigated for each mode of binding linkage (MBL). The tested MBLs were covalent linkage (CL), ionic linkage (IL), and polyelectrolyte-mediated ionic linkage (p-IL). Unlike the monolayers of zeolite crystals assembled on glass with a covalent linkage, the strong BS, very high DOC, and very high DCP do not decrease during monolayer assembly on glass through ionic linkages. This results indicate that the surface migration of crystals undergo linkage-nondestructively when crystals were attached to the substrates through ionic linkages.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제2B권3호
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• pp.125-132
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• 2002

PMSMS (permanent magnet synchronous motors) are widely used in industrial applications and home appliances because of their high torque to inertia ratio, superior power density, and high efficiency. For high performance control, accurate informations about the rotor position is essential. Sensorless algorithms have lately been studied extensively due to the high cost of position sensors and their low reliability in harsh environments. A novel position sensorless speed control for PMSMs uses indirect flux estimation and is presented in this paper. Rotor position and angular velocity are estimated by the proposed indirect flux estimation. Linkage flux and magnetic field flux are calculated by the voltage equations and the measured phase current without any integration. Instead of linkage flux calculation with integral operation, indirect flux and differential magnetic field are used for the estimation of rotor position. A proper rejection technique fur current noise effect in the calculation of differential linkage flux is introduced. The proposed indirect flux detecting method is free from the integral rounding error and linkage flux drift problem, because differential linkage flux can be calculated without any integral operation. Furthermore, electrical parameters of the PMSM can be measured by the proposed TCM (time compression method) for soft starting and precise estimation of rotor position. The position estimator uses accurate electrical parameters that are obtained from the proposed TCM at starting strategy. In the operating region, a proper compensation method fur temperature effect can compensate fir the estimation error from the variation of electrical parameters. The proposed novel position sensorless speed control scheme is verified by the experimental results.

• 한국도서관정보학회지
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• 제51권1호
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• pp.115-143
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• 2020

4차 산업혁명 시대의 도래로 데이터 중심의 융합 연구가 증가하고 있다. 이러한 연구는 정보의 식별 및 연계의 중요성을 증가시키고 있어, 이를 지원하기 위한 학술정보의 효과적인 관리 및 유통을 위한 방안 모색이 필요하다. 이에 본 연구는 국내외 주요 학술정보서비스 12개의 식별체계 현황과 연계 가능한 정보를 분석하여 학술정보를 식별하고 연계할 수 있는 방안을 제안하고자 하였다. 현황 분석은 2차에 걸쳐 진행되었으며, 각 서비스가 제공하고 있는 학술정보의 유형과 검색 가능한 항목, 연계 정보 유형, 사용 중인 식별체계 등을 살펴보았다. 분석 결과, 국내외 주요 학술정보서비스들은 영구 식별자와 더불어 자체 식별자를 중심으로 평균 3~4개의 정보를 직·간접적으로 연계하고 있다. 또한, 기계학습 방법론을 기반으로 하여 동일 학술정보를 반자동으로 식별하고, 해당 데이터를 수집, 구축하고 있다. 상기 분석 결과를 바탕으로 실무적인 측면에서 영구 식별자 중심의 학술정보 연계 방안과 사회적인 측면에서 기관 협력 네트워크 기반의 연계 방안을 제안하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.776-777
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• 2008

It is important to understand the relationship accurately between linkage flux distributions and machine characteristics for better design of multilayer-buried interior permanent magnet synchronous machines(IPMSM). This paper presents a improved calculation method for linkage flux of multilayer-buried IPMSM. From the analysis result, The proposed method shows that the calculated d,q linkage flux reflects a electromagnetic characteristic well in analysis model.

• 한국생산제조학회지
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• 제18권6호
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• pp.576-584
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• 2009

Up to now, it has been said that no satisfactory computer solution has been found for synthesizing four-bar linkage based on the prescribed coupler link curve. In our study, an algorithm has been developed to improve the design synthesis of four bar linkage based on the 5 precision points method. The suggested algorithm generates the desired coupler curve by using NURBS, and then the generated curve approximates as closely as possible to the desired curve representing coupler link trajectory. Also, when comparing each generated curve by constructing the control polygon, rapid comparison is easily achieved by applying convex hull of the control polygon. Finally, an optimization process using ADS is incorporated into the algorithm based on the 5 precision point method to reduce the total optimization process time. As for examples, two four bar linkages were tested and the result well demonstrated the effectiveness of the algorithm.

• 정보관리학회지
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• 제21권1호
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• pp.93-117
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• 2004

본 연구는 OPAC에서 계층 클러스터링을 응용하여 소장자료를 계층구조로 분류하여 열람하는데 사용될 수 있는 최적의 계층 클러스터링 모형을 찾기 위한 목적으로 수행되었다. 문헌정보학 분야 단행본과 학위논문으로 실험집단을 구축하여 다양한 색인기법(서명단어 자동색인과 통제어 통합색인)과 용어가중치 기법(절대빈도와 이진빈도), 유사도 계수(다이스, 자카드, 피어슨, 코싸인, 제곱 유클리드), 클러스터링 기법(집단간 평균연결, 집단내 평균연결, 완전연결)을 변수로 실험하였다. 연구결과 집단간 평균연결법과 제곱 유클리드 유사도를 제외하고 나머지 유사도 계수와 클러스터링 기법은 비교적 우수한 클러스터를 생성하였으나, 통제어 통합색인을 이진빈도로 가중치를 부여하여 완전연결법과 집단간 평균연결법으로 클러스터링 하였을 때 가장 좋은 클러스터가 생성되었다. 그러나 자카드 유사도 계수를 사용한 집단간 평균연결법이 십진구조와 더 유사하였다.