• 한국산학기술학회논문지
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• 제10권3호
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• pp.482-487
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• 2009

본 연구에서는 MR 유체를 특징으로 하는 대시포트형 마운트를 제안하고, 제안된 MR유체 마운트의 동적지 배방정식을 구하였다. 또한, 자극의 구조 및 형상과 관련된 설계인자의 변화가 솔레노이드에서의 자계 발생에 미치는 영향에 대하여 관찰하였다 솔레노이드에서 발생하는 자기 특성에 대하여 살펴보기 위하여 자극의 유효길이와 코어 중심부의 구조를 달리하여 설계인자로 선정하였다. 등가자기회로법를 이용하여 솔레노이드에서의 자기 특성의 변화를 살펴보고, 이를 상용소프웨어에 의한 계산 결과와 비교하였다. 등가자기회로법에 의한 계산 결과, 자극의 유효길이가 증가할수록 자기저항은 감소하여 자속밀도가 증가하는 경향을 나타내지만, 그 밖의 자기 특성의 변화는 작게 나타났다. 상용 소프트웨어를 이용한 결과와 등가자기회로에 의한 결과는 유사한 경향을 나타내는 것을 확인하였다.

• 지능정보연구
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• 제12권1호
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• pp.107-123
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• 2006

이 논문은 정규문법과 동등한 의미를 가지는 일반적인 이진 이차 재귀 신경망(Generalized Binary Second-order Recurrent Neural Networks: GBSRNN)의 구조 및 학습 방법을 제안하며 이를 이용하여 정규언어를 인식하는 어휘분석기 구현을 소개한다. GSBRNN는 성분들의 이진값 표현으로 정규문법과 동치인 모든 표현에 대하여 하드웨어로 표현할 수 있는 방법을 제공하며 정규 문법과의 구조적 관련성을 보여준다. 정규문법에서 심볼들의 개수 m, 비단말 심볼의 개수 p, 단말 심볼의 개수 q, k인 문자열이 입력된다고 할 때, GBSRNN의 크기는 $O(m(p+q)^2)$ 이고 병렬처리 시간은 O(k)이며 순차처리 시간은 $O(k(p+q)^2)$이다.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2284-2291
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• 2018

This paper deals with optimum design of surface mounted permanent magnet synchronous motor (SPMSM) for automotive component. For a compact system structure, it was designed as a motor with a 14-pole 12-slot concentrated winding and hollow shaft. The motor is a thin type structure which stator outer diameter is relatively large compared to its axial length and is designed to have a high magnetic saturation for increasing the torque density. Since the high magnetic saturation in the stator core increases the axial leakage flux, a 3-dimensional (3-D) finite element analysis (FEA) is indispensable for torque analysis. However, optimum designs using 3-D FEA is inefficient in terms of time and cost. Therefore, equivalent 2-D FEA which is able to consider axial leakage flux is applied to the optimization to overcome the disadvantages of 3-D FEA. The structure for cost reduction is proposed and optimum design using equivalent 2-D FEA has been performed.

• Journal of Electrical Engineering and Technology
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• 제9권6호
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• pp.1960-1966
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• 2014

The rotor overhang is used to enhance the air-gap flux and improve the power density. Due to the asymmetry in the axial direction caused by the overhang, a time consuming 3D analysis is necessary when designing a motor with overhang. To solve this problem, this paper proposes an equivalent magnetic circuit model (EMCM) which takes account overhang effects without a 3D analysis by using effective air-gap length. The analysis time can be reduced significantly via the proposed EMCM. A reduction in the analysis time is essential for a preliminary design of a motor. In order to verify the proposed model, a 3-D finite-element method (FEM) analysis is adopted. 3-D FEM results confirm the validity of the proposed EMCM.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권8호
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• pp.413-424
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• 2002

Recently, in the linear motion system, high performances are required In dynamic characteristics. Vector control method is capable of instantaneous thrust control can meet these high performance requirements. Linear induction motor(LIM) have static and dynamic end effects due to its finite core length, so that per-phase impedances are asymmetric and an air gap flux distribution is distorted. These points of the d-q axis equivalent circuit model considering both end effects is more complicated. This paper proposes the d-q axis equivalent circuit and the vector control method considering both static and dynamic end effects of the LIM. As a result, it is shown that the results of the equivalent circuit method(ECM) have a good agreement with those of the finite element method(FEM).

• 한국기계가공학회지
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• 제7권2호
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• pp.66-71
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• 2008

The data of the deformation and the stress according to time are studied at upper model of press and lower model of the blanking plate applied by press with the width, length and height of 0.4 m and 0.6 m respectively. The press is pushing downward on the plate fixed at the lower floor. These data are compared and investigated through this study. By using these results, there is the maximum deformation at 4 corners in the lower plate model of aluminium alloy fixed at lower floor. This deformation incase of elapsed time of 0.6 second becomes 4 times as much as in case of elapsed time of 0.2 second. The quantity of deformation at the lower plate model becomes more than at the upper press model to the extent of 10%. At the lower plate model of aluminium alloy, there is the maximum Von-Mises equivalent stress at 4 corners and both sides of middle area on the lower plate model of aluminium alloy. This stress in case of elapsed time of 0.6 second becomes 6 times as much as in case of elapsed time of 0.2 second. The Von-Mises equivalent stress of lower plate model becomes 2 times as much as that of upper press mode.

• Steel and Composite Structures
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• 제22권3호
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• pp.613-625
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• 2016

The joints of the new prefabricated concrete assemble beam-column joints are put together by the hybrid joints of inserting steel under post-tensioned and non-prestressed force and both beams and columns adopt prefabricated components. The low cyclic loading test has been performed on seven test specimens of beam-column joints. Based on the experimental result, the rotation capacity of the joints is studied and the $M-{\theta}$ relation curve is obtained. According to Eurocode 3: Design of steel structures and based on the initial rotational stiffness, the joints are divided into three types; by equivalent bending-resistant stiffness to the precast beam, the equivalent modulus of elasticity $E_e$ is elicited with the superposition method; the beam length is figured out that satisfies the rigid joints and after meeting the requirements of application and safety, the new prefabricated concrete assemble beam-column joints can be regarded as the rigid joints; the design formula adopted by the standard of concrete joint classification is theoretically derived, thereby providing a theoretical basis for the new prefabricated concrete structure.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.310-315
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• 2008

Authors design a rotary-type small-scaled linear induction motor(LIM) and a performance test machine before manufacturing a real-scaled LIM for a railway transit. The designed LIM is a single-sided, short primary type and its primary has 4 poles. The rated power is 10(kW). In order to analyze characteristics of the LIM, authors use a mixed 2D-3D FEM analysis. 3-D FEM analysis is used for calculating a distribution of eddy-current on the semi-caped AL-sheet of the secondary reaction. Authors calculate a correction factor of conductivity and an equivalent conductivity on the secondary AL-sheet using a normalized eddy-current. The equivalent conductivity which is calculated in this way includes a transverse edge-effect of the LIM. Authors apply the equivalent conductivity on the secondary AL-sheet of 2D-FEM model and get performance characteristics of the LIM. Basic characteristics such as thrust and normal force, input current, efficiency and power factor of the LIM have been analyzed with the variation of frequency and speed. In order to apply an air-gap control system, the variation of the basic characteristics have been analyzed with the air-gap length variation of the LIM. Finally, authors introduce an operation mode using the air-gap control system and conduct a research on feasibility of the system.

• 한국안광학회지
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• 제15권3호
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• pp.201-206
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• 2010

목적: 본 연구는 유치원생들을 대상으로 안광학 성분 값들과 굴절이상도 간의 상관성을 알아보고자 하였다. 방법: 대상자는 안질환이 없는 유치원생 80안으로 하였다. 굴절검사, 각막굴절력, 각막곡률반경, 안축장, 전방깊이를 검사하고 분석 하였다. 안축장과 각막 굴절력사이에서 가장 높은 상관성을 보였다(r=-0.674, p=0.000). 키, 몸무게, 안축장(AL)/각막곡률반경(CR)비가 안축장과 양의 상관성을 보였다(r=0.351, r=0.408, r=0.488). 굴절이상과 각막굴절력은 안축장과 음의 상관성을 보였다(r=-0.302, r=-0.674). 전방깊이, 각막굴절력은 AL/CR 비와 양의 상관성을 보였다(r=0.422, r=0.280). 굴절이상, 각막곡률반경은 AL/CR 비와 음의 상관성을 보였다(r=-0.448, r=-0.396). 결론: 취학 전 어린들에 있어서 눈의 굴절이상을 진단하는데 AL/CR 비가 매우 중요한 지표임을 알 수 있었다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권5호
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• pp.325-331
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• 2004

The multiobjective optimization (MO) problem usually includes the conflicting objectives and the use of conventional optimization algorithms for MO problem does not so good approach to obtain an effective optimal solution. In this paper, genetic algorithm (GA) as an effective method is used to solve such MO problem of brushless DC motor (BLDCM). 3D equivalent magnetic circuit network (EMCN) method which enables us to reduce the computational burden is also used to consider the 3D structure of BLDCM. In order to effectively obtain a set of Pareto optimal solutions in MO problem, ranking method proposed by Fonseca is applied. The objective functions are decrease of cogging torque and increase of torque respectively. The airgap length, teeth width and magnetization angle of PM are selected for the design variables. The experimental results are also shown to confirm the validity of the optimization results.