• The Korean Journal of Applied Statistics
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• v.23 no.4
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• pp.767-776
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• 2010

Frontier (1976) suggested a criterion based on the expected length of ordered random intervals under the Broken-stick model (Barton and David, 1956) to determine the optimal number of principal components retained. It is considered to be one of the methods that provide the most consistent simulation results (Jackson, 1993). This study is aimed to propose a method using the distribution of ordered random intervals to evaluate the contribution of principal components. We also examine several types of Gini indices along with the corresponding Lorenz curves to visualize the overall equivalence of those contributions.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.10 s.175
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• pp.195-201
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• 2005

A laterally driven electromagnetic microactuator (LaDEM) is presented, and a micro-optical switch is designed and fabricated as a possible application. LaDEM provides parallel actuation of the microactuator to the silicon substrate surface (in-plane mode) by the Lorentz force. Poly-silicon-on-insulator (Poly-SOI) wafers and a reactive ion etching (RIE) process were used to fabricate high-aspect-ratio vertical microstructures, which allowed the equipment of a vertical micro mirror. A fabricated arch-shaped leaf spring has a thickness of $1.8{\mu}m$, width of $16{\mu}m$, and length of $800{\mu}m$. The resistance of the fabricated structure fer the optical switch was approximately 5$\Omega$. The deflection of the leaf springs increases linearly up to about 400 mA and then it demonstrates a buckling behavior around the current value. Owing to this nonlinear phenomenon, a large displacement of $60{\mu}m$ could be measured at 566 mA. The displacement-load relation and some dynamic characteristics are analyzed using the finite element simulations.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.487-489
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• 2018

This paper presents chaotic Lorenz system implementation for secure data communication applications. In this work chaotic signal is generated by a PIC18F family based microcontroller, XC8 compilers have been utilized for the compilation of C code of microcontroller program. For simulation work Matlab and Proteus platforms were utilized and finally, chaotic time waveforms, 2D and 3D chaotic attractor were obtained and secure communication waveforms were achieved successfully.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.04a
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• pp.103-106
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• 2004

본 본문은 하이퍼카오스, 로렌츠, 해밀톤 방정식과 같은 여러 종류의 카오스 회로를 이동 로봇에 내장하여 카오스 이동 로봇을 구성하고 이 카오스 이동 로봇이 어느 임의 평면을 카오스 궤적을 가지고 탐색하다가 목표물에 근접하거나 탐색하고자 하는 목표물이 확인되면 집중적인 탐색을 실행하는 방법을 제시하고 그 결과를 검증하였다. 목표물 탐색에서는 장애물 회피와 유사한 카오스 궤적을 가지고 탐색하도록 하는 알고리즘을 개발하고 그 결과를 검증하였으며 이에 대한 타당성을 확인하였다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.04a
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• pp.121-124
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• 2004

본 본문은 하이퍼카오스, 로렌츠, 해밀톤 방정식과 같은 여러 종류의 카오스 회로를 이동 로봇에 내장하여 카오스 이동 로봇을 구성하고 이 카오스 이동 로봇이 어느 임의 평면을 카오스 궤적을 가지고 탐색하다가 장애물을 만나거나 근접하게 되면 장애물을 회피하는 방법을 제시하고 그 결과를 검증하였다. 목표물 회피에서는 장애물 탐사와 유사한 카오스 궤적을 가지고 회피하도록 하는 알고리즘을 개발하고 그 결과를 검증하였으며 이에 대한 타당성을 확인하였다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1995.10a
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• pp.82-85
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• 1995

Magnetic-electrolytic-abrasive polishign(MEAP) systemwas newly developed and the finishing characteristics of Cr-coated roller was analyzed. The paper describes the operational principle of MEAP system and magnetic field effect on the MEAP process by experimental results. The finishing characteristics and optimal finishing condition for Cr-coated roller were experimented and analyzed.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.80-81
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• 2002

MR(magnetoresistance)은 물질의 저항이 자기장에 의해 변하는 물리적인 변화(physical MR)와 기하학적인 요소, 즉 sample의 모양과 contact의 크기 등에 의한 변화(geometric MR)의 합으로 나타낸다.[1] Physical MR은 자기장에 따른 비저항 또는 이동도(mobility)의 변화로 나타낼 수 있고, geometric MR은 로렌츠 힘에 의해 전류의 흐르는 방향이 변하면서 일어난다. 본 연구에서는 physical MR이 거의 없는 반도체(InAs)와 비교적 큰 physical MR을 가지는 반도체(HgCdTe)의 geometric factor를 고려한 MR의 향상에 대하여 연구하였다. (중략)

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2348-2350
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• 2005

LHM (Left Handed Material)은 특정 주파수 범위에서 음의 유전율과 투자율을 가지는 물질이며 유효 유전율과 투자율은 분산 특성을 가지고 로렌츠(Lorentz) 물질과 비슷한 형태를 가진다. 본 논문에서는 FDTD (Finite Difference Time Domain) 법을 바탕으로 한 PLRC (Piecewise Linear Recursive Convolution) 법을 이용하여 LHM 내의 유효 전파특성을 모의한다. 모의실험 결과는 음의 유전율과 투자율을 가지는 주파수 범위를 보여준다.

• Journal of Digital Convergence
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• v.18 no.6
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• pp.33-44
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• 2020

The main objective of this study is to measure the concentration and deconcentration of the domestic freight forwarding system which illustrate the development trends in this industry. In this study, Herfindal-Hirschman index (HHI), shift-share analysis (SSA), and GINI coefficient combined with Lorenz curves were employed to investigate the domestic freight forwarders. The results are as follows: first, the HHI was used to assess the concentration of domestic freight forwarders in Vietnam. The downward trend from 0.117 in 2008 to 0.083 in 2018 indicate the deconcentration of domestic freight forwarders in Vietnam. Second, the SSA results indicated that the company Transimex showed the best performance with a shift effect of million VND 1,906,515 and a ABSGR value of million VND 2,158,232. Third, the GINI index go down from 0.468 to 0.393 in 2008-2018 as follow and the Lorenz curves covered a large part which make more demonstrate the deconcentration trend of freight forwarding in Vietnam. The results show that deconcentration is a trend in 2008-2018. The results of this study provides relevant data on freight forwarders which are not easily accessible to related stakeholders.

• 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.