• Title/Summary/Keyword: Kyuwon

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Monte Carlo Study of Layered Heisenberg Ferromagnet

  • Lee, Kyuwon
    • Journal of Magnetics
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    • v.6 no.4
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    • pp.119-121
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    • 2001
  • Monte Carlo simulation was employed to study the phase transition in the classical Heisenberg ferromagnet with variable interlayer interactions. The measured transition temperatures show a strong logarithmic dependence on J/J'where J and J'are the intralayer and the interlayer exchange interaction, respectively. The results were compared with the theoretical expectations and an empirical formula for the critical coupling was stained.

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Stress Assesment based on Bio-Signals using Random Forest Algorithm (랜덤포레스트 기법을 이용한 생체 신호 기반의 스트레스 평가 방법)

  • Lim, Taegyoon;Heo, Jeongheon;Jeong, Kyuwon;Ghim, Heirhee
    • Journal of the Korean Society of Safety
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    • v.35 no.1
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    • pp.62-69
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    • 2020
  • Most people suffer from stress during day life because modernized society is very complex and changes fast. Because stress can affect to many kind of physiological phenomena it is even considered as a disease. Therefore, it should be detected earlier, then must be released. When a person is being stressed several bio-signals such as heart rate, etc. are changed. So, those can be detected using medical electronics techniques. In this paper, stress assessment system is studied using random forest algorithm based on heart rate, RR interval and Galvanic skin response. The random forest model was trained and tested using the data set obtained from the bio-signals. It is found that the stress assessment procedure developed in this paper is very useful.

Pose Estimation of a Cylindrical Object Using Genetic Algorithm (유전자 알고리즘을 이용한 원기둥형 물체의 자세 추정 방법)

  • Jeong Kyuwon
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.14 no.3
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    • pp.54-59
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    • 2005
  • The cylindrical object are widely used as mechanical parts in the manufacturing process. In order to handling those objects using a robot or an automated machine automatically, the pose of the object must be known. The pose can be described by two rotation angles; one angle about the x axis and the other about the y axis. In the many previous researches these angles were obtained by the computationally intensive algorithm, that is, fitting the data as a polynomial and doing pseudo inverse. So that, this method required high performance microprocessor. In this paper in order to avoid complex computation, a new method based on a genetic algorithm is proposed and analyzed through a series of simulations. This algorithm utilized the geometry of the cylindrical shape. The simulation results show that this method find the pose angles very well In most cases, but the computation time is randomly changed because the genetic algorithm is basically one of the random search method.

Load Measurement Algorithm for a Vehicle Wheel Dynamometer (자동차 휠 동력계의 하중 검출 신호 처리 방법)

  • Lee, Jinsung;Jeong, Kyuwon
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.26 no.4
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    • pp.418-424
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    • 2017
  • A wheel dynamometer was installed between the rim and axle hub to measure the forces and moments applied to a vehicle. The wheel dynamometer was composed of sensing and signal processing components. Because the sensing component contained a complex structure to sense the six components of the forces and moments and the wheel rotated along with the vehicle movement, sophisticated signal processing hardware and a software algorithm were used. The strains and the calibration matrices of the wheel dynamometer along the wheel rotation angle were investigated using FEM. From the analysis, the calibration matrices were simplified using a spline interpolation. Based upon these results, the signal processing component could be effectively designed and the firmware software could be simplified.

Study on the Removal of Hydrogen Sulfide in Landfill Gases using Hydroquinone Clathrate (하이드로퀴논을 이용한 매립가스 내 황화수소 제거에 관한 연구)

  • Han, Kyuwon;Moon, Donghyun;Shin, Hyungjoon;Lee, Jaejeong;Lee, Gangwoo
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.05a
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    • pp.189.2-189.2
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    • 2011
  • 매립가스(LFG)는 약 50v/v% 이상의 메탄가스로 이루어져 있어 LFG의 자원화 사업은 국내 신 재생에너지를 이용한 발전사업 중 태양광사업 다음으로 활발히 진행되고 있다. LFG의 대표적인 활용기술로는 가스엔진, 가스터빈 및 증기터빈을 이용한 발전과 중질가스 및 고질가스 형태의 연료로 생산하는 방식 등이 있으며 이러한 분야에 매립지가스를 적용하기 위해서는 장치 부식의 주 원인이 되는 황화수소 가스의 제거가 반드시 이루어져야 한다. 본 연구에서는 황화수소 제거를 위해 하이드레이트와 마찬가지로 동공을 형성하여 가스의 포집과 저장이 가능한 하이드로퀴논(HQ)을 이용하고자 한다. HQ은 $0^{\circ}C$ 부근에서 해리되는 하이드레이트와 달리 상온에서 고체 형태로 구조를 유지할 수 있어 가스의 포집 및 저장에 용이한 장점이 있다. 메탄, 이산화탄소, 황화수소 혼합가스에서 황화수소 90% 이상 제거를 목적으로 HQ와 반응시켜 동공 내에 이들 가스의 포집여부를 확인하였다.

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