• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.11
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• pp.1147-1152
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• 2004

The objective of this work is to develop a new design method to find optimal coils, especially the optimal coil configuration of an optical pickup actuator. In designing actuator coils, the developed Lorenz force in the coils along the desired direction should be made as large as possible while forces and torques in other directions should be made as small as possible. The design methodology we are developing is a systematic approach that can generate optimal coil configurations for given permanent magnet configurations. To consider the best coil configuration among all feasible coil configurations, we formulate the design problem as a topology optimization of a coil. The present formulation for coil design is noble in the sense that the existing topology optimization is mainly concerned with the design of yokes and permanent magnets and that the optimization of actuator coils is so far limited within shape or size optimization. Though the present design methodology applies to any problem, the specific design example considered is the design of fine-pattern tracking and focusing coils.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.41-46
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• 2013

IIn this paper, active trasfemoral prosthesis leg is designed for the handicapped who lost their legs upon knee. It is important to design proper knee joint to mimic walking motion of hyman. 1 degree-of-freedom active trasfemoral prosthesis leg is designed with knee joint. Operating angle and torque have been calculated using kinematics of three linkages in prosthesis leg. Finite element analysis of major components is performed to evaluate the safety under operating condition and to reduce weights. Minimum volumes of components are obtained by optimization as satisfying safety requirements. The results show that about 35% of weight of components is reduced.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.5
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• pp.503-510
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• 2011

This paper presents a method of optimizing the blade pitch and generator torque controllers which have been already designed for an existing wind turbine generator system. Since the highly nonlinear and uncertain characteristics of the wind turbine generator can not be fully considered in the controller design phase, some parameters such as control gains must be tuned during the field implementation phase. In this paper, nonlinear simulation software, which is based high fidelity wind turbine model, and optimization technique are effectively combined and used to tune a set of gains for the blade pitch and the generator torque controllers. Simulation results show that the baseline controllers can be effectively optimized to reduce the errors in wind turbine rotor speed and generator power output controls as well as twisting of the high and low speed shafts.

• Elastomers and Composites
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• v.44 no.4
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• pp.366-372
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• 2009

The present study covers the optimal design for a lens module in a mobile phone camera by using the design of experiments (DOE) and finite element (FE) analysis. FE analyses are performed to investigate the effect of design parameters on the amount of torque required to assemble a barrel and a housing part. The DOE approach is then performed to optimize the design parameters in order to maintain an appropriate torque with less variations.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.864-865
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• 2007

외전형 유도전동기는 내전형에 비해 회전자가 외부에 존재하는 특징을 가지고 있어서 제품의 소형화 및 경량화를 시킬 수 있다는 장점이 있다. 하지만 외전형은 회전자의 직경이 내전형에 비하여 크기 때문에 조립 공정상에 존재하게 되는 회전자와 고정자간의 이심률에 따른 제품 전체의 불균형력이 상대적으로 크며, 이로 인해 모터의 정속적인 운전 방해 및 불규칙한 출력토크로 인한 제품 작동상의 오류발생이 더 크게 나타난다. 본 논문에서는 외전형 유도전동기에서 존재하는 이심률의 크기에 따른 불균형력이 최소화 될 수 있는 슬롯형태를 찾기 위해 회전자 슬롯의 형태를 전폐형, 반폐형, 개구형태의 3가지형태로 변경시킨 후, 이를 전자장 해석을 통해 불균형력을 비교하였다. 또한 이심률이 증가함에 따라 나타나는 불균형력의 증대를 슬롯 형태에 따라 비교 분석하여, 불균형력에 최적화된 외전형 모터의 슬롯형태를 알아보았다.

• Annual Conference on Human and Language Technology
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• 2020.10a
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• pp.441-445
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• 2020

토큰화(Tokenization)는 사람이 작성한 자연어 문장을 기계가 잘 이해할 수 있도록 최소 단위인 토큰으로 분리하는 작업을 말하여, 이러한 토큰화는 자연어처리 전반적인 태스크들의 전처리에 필수적으로 사용되고 있다. 최근 자연어처리 분야에서 높은 성능을 보이며, 다양한 딥러닝 모델에 많이 활용되고 있는 SentencePiece 토큰화는 여러 단어에서 공통적으로 출현하는 부분단어들을 기준으로, BPE 알고리즘을 이용하여 문장을 압축 표현하는 토큰화 방법이다. 본 논문에서는 한국어 기반 특허 문헌의 초록 자연어 데이터를 기반으로 SentencePiece를 비롯한 여러 토큰화 방법에 대하여 소개하며, 해당 방법을 응용한 기계번역 (Neural Machine Translation) 태스크를 수행하고, 토큰화 방법별 비교 평가를 통해 특허 분야 자연어 데이터에 최적화된 토큰화 방법을 제안한다. 그리고 본 논문에서 제안한 방법을 사용하여 특허 초록 한-영 기계번역 태스크에서 성능이 향상됨을 보였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.2
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• pp.515-522
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• 1991

Determining the motion using optimal technique about traveling time and trajectory planning has been studied often in recent years, but the study of determining the optimal robot dimensions is rare, the authors attempt to find out the least driving torques and energy as the optimization of link length ratio referred to 2R SCARA and 3R robot manipulators. For the given linear path with triangular velocity profile, the inverse kinematic and dynamic problems are examined in order to lead into solution of problem, which is suggested for optimal design of link lengths. Accordingly, optimal link length ratio is obtained with respect to each case.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.878-879
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• 2011

본 논문에서는 10극 12슬롯의 분수슬롯을 가지는 영구자석 동기전동기의 권선방법을 알아보고자 한다. 권선방법은 수학적인 수식을 통해 계산되었고 권선법에 따른 결과는 2차원 유한요소법으로 검증을 하였다. 무부하 역기전력과 토크 파형을 비교하여 분수슬롯 권선법의 최적화된 설계방법을 찾고자 하였다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1047-1048
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• 2011

본 논문에서는 IPMSM(Interior Permanent Magnet Synchronous Motor)의 단점인 치, 슬롯 구조에 의한 코깅 토크를 최소화시켜 정토크 특성을 향상시키기 위해 배리어(Barrier)와 노치(Notch)를 설치하였다. 실험계획법 및 유한요소해석을 통하여 최적 설계를 수행하고 그에 따른 제반 특성과 진동 및 소음의 원인이 되는 가진력 특성을 고찰 하였다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.826-827
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• 2011

The selection of optimum parameters in electromagnetic design usually requires optimization of multimodal, non linear functions. This leads to extensive calculations which pose a huge inconvenience in the design process. This paper proposes a novel algorithm for dealing efficiently with this issue. Through the use of contour line concept coupled with Kriging, the algorithm finds out all the peaks in the problem domain with as few function calls as possible. The proposed algorithm is applied to the magnet shape optimization of an axial flux permanent magnet synchronous machine and the cogging torque was reduced to 79.8% of the initial one.