• 한국광학회지
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• 제28권6호
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• pp.263-272
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• 2017

넓은 시야를 가지는 광학계에서는 전반부는 음의 굴절능, 후반부는 양의 굴절능을 가지는 inverted telephoto 구조가 일반적으로 사용되고 있고, 2반사광학계에서는 inverse Cassegrain system이 inverted telephoto 구조에 해당한다. 하지만 통상적인 회전대칭 구성의 inverse Cassegrain system에서는 시야가 가려지고 광선의 차폐가 심한 문제점이 있다. 이 연구에서는 이점을 고려하여 inverse Cassegrain system의 제2면에 조리개를 두어 시야를 넓히고, 광선의 차폐가 없는 비축시야만을 사용하는 광시야 비축 2반사광학계를 설계하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 추계학술대회 논문집
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• pp.243-244
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• 2013

This paper introduces the application of Profibus field bus communication in HVDC power system. Discusses about the configuration of HVDC system and the structure of control and protection system. Analyzes and designs the network configuration of field device level. Using OPAS engineering tool to config IO system and at the same time monitor data in SCADA HMI.

• 천문학회지
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• 제6권1호
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• pp.15-17
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• 1973

Observational implication for a possible presence of a magnetic monopole-like field in the visible layers of sunspots is examined by constructing a magnetostatic model of sunspots with a monopole-like field configuration. The resulting monopole approximation for a magnetic structure of spots is found to be compatible with the observations within a certain limited range of optical depth, which happens to lie mostly in its visible range.

• 한국초전도ㆍ저온공학회논문지
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• 제15권1호
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• pp.29-34
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• 2013

AMR (Active Magnetic Regenerative) refrigerators require the large variation of the magnetic field and a HTS magnet can be used. The amount of AC loss is very important considering the overall efficiency of the AMR refrigerator. However, it is very hard to estimate the precise loss of the HTS magnet because the magnetic field distribution around the conductor itself depends on the coil configuration and the neighboring HTS wires interact each other through the distorted magnetic field by the screening current Therefore, the AC loss of HTS magnet should be calculated using the whole configuration of the HTS magnet with superconducting characteristic. This paper describes the AC loss of the HTS magnet by an appropriate FEM approach, which uses the non-linear characteristic of HTS conductor. The analysis model is based on the 2-D FEM model, called as 'magnetic field formulation and edge-element model', for whole coil configuration in cylindrical coordinates. The effects of transport current and stacked conductors on the AC loss are investigated considering the field-dependent critical current. The PDE model of 'Comsol multiphysics' is used for the FEM analysis with properly implemented equations for axisymmetric model.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 영호남 합동 학술대회 및 춘계학술대회 논문집 센서 박막 기술교육
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• pp.121-124
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• 2006

It is widely know that one of the most important tasks is the research of plasma for the purpose o nuclear fusion, is to make a stable confinement of high ${\beta}$ value plasma. And, for making the stable confinement, pinch pl-asma produced by reversed field has been mainly studied yet. Magnetic field has been used to hold plasma at high temperature for a long time. Reverse field has shown unstable process. Using ratio frequency, the author could control the instability of the process and formed a stable erversed field. Inthe experiment let a reversed field configuration from by adding-Bias field in advance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2187-2189
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• 2005

It is widely know that one of the most important tasks is the research of plasma for the purpose o nuclear fusion, is to make a stable confinement of high ${\beta}$ value plasma. And, for making the stable confinement, pinch p1-asma produced by reversed field has been mainly studied yet. Magnetic field has been used to hold plasma at high temperature for a long time. Reverse field has shown unstable process. Using ratio frequency, the author could control the instability of the process and formed a stable erversed field. Inthe experiment let a reversed field configuration from by adding-Bias field in advance.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.572-575
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• 2008

Flow-field design has much influence over the performance of proton exchange membrane fuel cell (PEMFC) because it affects the pressure magnitude and distribution of the reactant gases. To obtain the pressure magnitude and distribution of reactant gases in four kinds of flow-field designs without additional measurement equipment, computational fluid dynamics (CFD) analysis was performed. After the CFD analysis, the performance values of PEMFC according to the flow-field configurations were measured via a single cell test. As expected, the pressure differences due to different flow-field configurations were related to the PEMFC performance because the actual performance results showed the same tendency as the results of the CFD analysis. A large pressure drop resulted in high PEMFC performance. So, the single serpentine configuration gave the highest performance. On the other hand, the parallel flow-field configuration gave the lowest performance because the pressure difference between inlet and outlet was the lowest.

• 천문학회지
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• 제44권5호
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• pp.143-150
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• 2011

This paper reports a characteristic motion of a polarity inversion line (PIL) formed at the solar surface, which is newly found by performing a three-dimensional magnetohydrodynamic simulation of flux emergence in the Sun. A magnetic flux tube composed of twisted field lines is assumed to emerge below the surface, forming a bipolar region with a PIL at the surface. A key finding is the successive half-turn rotation of the PIL, leading to the formation of a quadrupolar-like region at the surface and a magnetic configuration in the corona; this configuration is reminiscent of, but essentially different from the so-called inverse-polarity configuration of a filament magnetic field. We discuss a physical mechanism for producing the half-turn rotation of a PIL, which gives new insights into the magnetic structure formed via flux emergence. This presents a reasonable explanation of the configuration of a filament magnetic field suggested by observations.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 추계학술대회
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• pp.655-658
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• 2016

고성능 디지털 회로 구현에 매우 많이 사용되는 Xilinx사의 7-Series FPGA(Field Programmable Gate Array)는 configuration memory가 SRAM 기반으로 제작되어 configuration memory에 소프트 에러(soft error)가 발생하는 경우 FPGA는 오동작하게 된다. Xilinx사에서 제공하는 SEM(Soft Error Mitigation) Controller를 이용하면 configuration memory에서 발생하는 소프트 에러의 영향을 줄일 수 있다. SEM Controller는 FPGA의 configuration memory 영역에 추가된 ECC(Error Correction Code)와 CRC(Cyclic Redundancy Code) 기능을 이용하여 configuration memory에 발생한 소프트 에러를 감지하여 필요시 partial reconfiguration 과정을 수행하여 FPGA의 기능을 소프트 에러 발생 이전으로 복구한다. 본 논문에서는 Xilinx사의 7-Series FPGA에서 SEM Controller를 이용하여 configuration memory의 소프트 에러를 검출하고 정정할 때 FPGA의 신뢰도를 가용성(availability) 관점에서 분석한다. 이를 위해 SEM Controller의 소프트 에러 정정 성능에 따른 가용성 함수를 유도하고 그 효과를 검토한다. 연구 결과는 소프트 에러가 발생하는 환경에서 동작하는 SRAM 기반 FPGA의 신뢰성 예측에 사용할 수 있을 것으로 기대된다.

• 대한수학회지
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• 제45권5호
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• pp.1443-1482
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• 2008

In this paper we define a Myller configuration in a Finsler space and use some special configurations to obtain results about Finsler subspaces. Let $F^{n}$ = (M,F) be a Finsler space, with M a real, differentiable manifold of dimension n. Using the pull back bundle $({\pi}^{*}TM,\tilde{\pi},\widetilde{TM})$ of the tangent bundle $(TM,{\pi},M)$ by the mapping $\tilde{\pi}={\pi}/TM$ and the Cartan Finsler connection of a Finsler space, we obtain an orthonormal frame of sections of ${\pi}^{*}TM$ along a regular curve in $\widetilde{TM}$ and a system of invariants, geometrically associated to the Myller configuration. The fundamental equations are written in a very simple form and we prove a fundamental theorem. Important lines in a Finsler subspace are defined like special lines in a Myller configuration, geometrically associated to the subspace: auto parallels, lines of curvature, asymptotes. Torse forming vector fields with respect to the Cartan Finsler connection are characterized by means of the invariants of the Frenet frame of a versor field along a curve, and the new notion of torse forming vector fields in the sense of Myller is introduced. The particular cases of concurrence and parallelism in the sense of Myller are completely studied, for vector fields from the distribution $T^m$ of the Myller configuration and also from the normal distribution $T^p$.