TE 모드의 위상변화만을 일으키는 P-I-i-I-N GaAs/Al_0.35Ga_0.65As 도파로 위상변조기의 제작 및 변조 특성

김선필,이상선,이석,우덕하,김선호,Kim, Sun-Pil,Lee, Sang-Sun,Lee, Seok,Woo, Deok-Ha,Kim, Sun-Ho 한국광학회 2003 한국광학회지 Vol.14 No.2

TM 모드에는 영향을 끼치지 않으면서 TE 모드의 위상만을 변조시키는 P-I-i-I-N $GaAs/Al_{0.35}Ga_{0.65}As$ 도파로 위상변조기를 제작하였다. TE 모드에 대해서만 위상변조를 일으키게 하기 위해 P-I-i-I-N 구조를 선택하였다. Fabry-Perot 공명 방법을 이용해서 TE-와 TM 모드에 대해 $\lambda=1.55$\mu\textrm{m}$ 파종에서 각각 측정하였다. TE-편광된 빛에 대한 위상변조 효율은 $\Delta\phi=7.9^{\circ}/V.mm$ 였다. 이것은 비슷한 구조를 갖는 위상변조기의 변조 효율 보다 거의 2.5배정도 향상된 결과이다. 또한, TM-편광된 빛에 대해 서는 위상변조가 관측되지 않았다. We fabricated a P-I-i-I-N $GaAs/Al_{0.35}Ga_{0.65}As$waveguide phase modulator with significant phase shift for the TE mode but negligible for the TM mode. We selected the P-I-i-I-N structure to cause a phase shift about the TM mode. The wavelength of $\lambda=1.55$\mu\textrm{m}$ was measured for both the TE and TM modes, respectively. As a result, the measured phase shift efficiency ($\Delta\phi$) by using the Fabry-Perot resonance method was $7.9^{\circ}/V.mm$ for TE-polarized light. Also, no modulation was observed for TM-polarized light.

RF Sputtering법에 의한 산화주석 박막의 진공 열처리 효과

김선필,김영래,김성동,김사라은경,Kim, Sun-Phil,Kim, Young-Rae,Kim, Sung-Dong,Kim, Sarah Eun-Kyung 한국세라믹학회 2011 한국세라믹학회지 Vol.48 No.4

Tin oxide thin films were deposited by rf reactive sputtering and annealed at $400^{\circ}C$ for 1 h in vacuum. To minimize the influence such as reduction, oxidation, and doping on tin oxide thin films during annealing, a vacuum ambient annealing was adopted. The structural, optical, and electrical properties of tin oxide thin films were characterized by X-ray diffraction, atomic force microscope, UV-Vis spectrometer, and Hall effect measurements. After vacuum annealing, the grain size of all thin films was slightly increased and the roughness ($R_a$) was improved, however irregular and coalesced shapes were observed from the most of the films. These irregular and coalesced crystal shapes and the possible elimination of intrinsic defects might have caused a decrease in both carrier concentration and mobility, which degrades electrical conductivity.

Indirect inguinal hernia의 repair시 internal ring부위 transversalis fascia sling이용법

김선필,김정용,조현진,정양수 대한외과학회 1991 대한외과학회 학술대회 초록집 Vol.1991 No.5

무릎 신전 메카니즘에서의 모멘트암

김선필 경주대학교 정보전자기술연구소 2004 情報電子技術論叢 Vol.3 No.-

The paper shows that the moment arm of the knee extensor mechanism is equal to the perpendicular distance between the instantaneous screw axis and the line of action of the patellar ligament force, multiplied by the sine of the angle between those two lines. The tibia undergoes movements other than flexion-extension, most noticeably internal-external rotation about its long axis. Extension movements reflect a change in the direction of the screw axis of the knee. The angle between the screw axis and the patellar ligament force is not always 90 and also the perpendicular distance is a function of the location within knee. the location of the screw axis is in turn determined by the interaction between the geometry of articulating surface and the force vector of the muscles. Thus the moment arm exhibits a characteristic bell shape which peaks somewhere in the region 40-60 of flexion, and then decreases rather rapidly on either side of this peak.

부착슬립에 의한 강체변형을 고려한 철근콘크리트 보의 비선형해석

김선필,곽효경,Kim, Sun-Pil,Kwak, Hyo-Gyoung 한국전산구조공학회 2005 한국전산구조공학회논문집 Vol.18 No.1

An analytical procedure to analyze reinforced concrete (RC) beams subject to monotonic loadings is proposed on the basis of the moment-curvature relations of RC sections. Unlike previous analytical models which result the overestimation of stiffnesses and underestimation of structural deformations induced from ignoring the shear deformation and assuming perfect-bond condition between steel and concrete, the proposed relation considers the rigid-body-motion due to anchorage slip at the fixed end. The advantages of the proposed relation, compared with the previous numerical models, are on the promotion in effectiveness of analysis and reflection of influencing factors which must be considered in nonlinear analysis of RC beam by taking into account the nonlinear effects into the simplifying moment-curvature relation. Finally, correlation studies between analytical and experimental results are conducted to establish the applicability of the proposed model to the nonlinear analysis of RC structures. 이 논문에서는 단면성질을 나타내는 모멘트-곡률 관계에 토대를 둔 해석모델을 제안하였다. 기존의 제안된 해석방법에서는 모멘트-곡률 관계가 완전부착을 가정한 휨거동만을 주요한 거동으로 가정하여 구조물의 응답을 과소평가하고 강성을 과대평가한 것과는 달리 제안된 해석 방법에서는 접합부의 부착슬립에 의한 강체변형을 산정할 수 있는 알고리즘을 개발하였고 나아가 등가휨강성을 이용하여 부착슬립에 의한 강체변형을 고려한 철근콘크리트 구조물의 해석을 수행하였다. 또한 모멘트-곡률 관계를 철근의 항복점을 기준으로 두개의 직선으로 간편화 시킴으로써 해석의 효율성을 높이는 한편 고려해야 할 비선형 거동특성을 효과적으로 반영하였다. 마지막으로 철근콘크리트 구조물의 비선형 해석에 대한 제안된 모델식의 적용성을 검증하기 위하여 해석결과와 실험값들의 비교를 수행하였다.

유전자알고리즘을 이용한 인체 근골격 시스템의 최적화제어 모델 개발

김선필 慶州大學校 2005 論文集 Vol.18 No.2

The study investigated genetic algorithms for the optimal control model of maximum height vertical jumping. The model includes forward dynamic simulations by the neural excitation-control variables. Convergence of genetic algorithms is very slow. In this paper the micro genetic algorithm(micro-GA) was used to reduce the computation time. Then a near optimal solution from micro-GA was an inital solution for VF02, which is one of well-developed and proven nonlinear programming algorithms. These approach provided the successful optimal solution without a resonable initial guess.

Charging effect of In2O3 nano-particles embedded in polyimide layer for application as non-volatile nano-floating gate memory

김선필,이태희,이동욱,김은규,구현모,김영호,조원주 한국물리학회 2009 Current Applied Physics Vol.9 No.11

The memory charging effect of the nano-floating gate capacitor containing the In2O3 nano-particles embedded in polyimide layer was characterized. Self-assembled In2O3 nano-particles were created by chemical reaction between the polymer precursor and indium film, and then the particles size and density were about 7 nm and 5.8 × 1011 cm-2, respectively. From capacitance–voltage hysteresis originated from electrons charging in the In2O3 nano-particles through tunneling oxide from p-type Si wafer, the flat-band voltage shift was obtained up to about 3.4 V, when the sweeping gate voltage was from -6 to 6 V. The endurance ability of this capacitor showed up to 2 × 105 cycles during the programming at 5 V for 0.2 ms and erasing at -5 V for 1.8 ms processes. The memory charging effect of the nano-floating gate capacitor containing the In2O3 nano-particles embedded in polyimide layer was characterized. Self-assembled In2O3 nano-particles were created by chemical reaction between the polymer precursor and indium film, and then the particles size and density were about 7 nm and 5.8 × 1011 cm-2, respectively. From capacitance–voltage hysteresis originated from electrons charging in the In2O3 nano-particles through tunneling oxide from p-type Si wafer, the flat-band voltage shift was obtained up to about 3.4 V, when the sweeping gate voltage was from -6 to 6 V. The endurance ability of this capacitor showed up to 2 × 105 cycles during the programming at 5 V for 0.2 ms and erasing at -5 V for 1.8 ms processes.

전단빌딩의 최대 층간변위를 예측하기 위한 역량스펙트럼법 개발

김선필,김두기,곽효경,고성혁,Kim, Sun-Pil,Kim, Doo-Kie,Kwak, Hyo-Gyoung,Ko, Sung-Hyuk 한국전산구조공학회 2007 한국전산구조공학회논문집 Vol.20 No.3

다층구조물의 경우 변위보다 층간변위에 의해 구조물의 파괴가 발생되나 현행 국 내외 내진설계 규준에 제시된 역량스펙트럼 법에서는 변위에 의한 응답산정으로 층간변위를 정확히 예측할 수가 없었다. 따라서 본 논문에서는 다층구조물의 가장 기본적인 모델인 전단빌딩(Shear Building)에 대하여 기존의 역량해석법의 간편성과 장점을 변함없이 유지하면서, 구조물의 파괴에 직접적인 영향을 미치는 층간변위를 실제에 가깝게 예측하고 구조물의 내진성능을 평가할 수 있는 개선된 역량스펙트럼 법을 제안하고자 한다. 나아가 제안된 방법을 예제구조물에 적용하고 시간이력 해석결과와 비교함으로서 제안된 방법의 신뢰성에 대한 검증을 수행하였다. In the current domestic and overseas standards concerning seismic design, especially on the capacity & demand spectra in the multi-story building, failure is caused more by story drift than by displacement; and the existing capacity spectrum method (CSM) does not make a close estimate of story drift because response is derived using displacement. Therefore, this paper proposes an improved CSM to estimate story drift and its direct effect on the collapse of structures, yet still maintaining the same advantage and convenience of the existing CSM about a most basic model of multi-story building: shear building. To establish its reliability, the proposed method is applied to an example model and results are then compared with those obtained through nonlinear time-history analysis.

WiFi 신호를 이용한 기점기반 위치 추정 연구

김선필,김남기 한국정보기술학회 2012 한국정보기술학회논문지 Vol. No.

본 논문은 WiFi 신호를 이용한 기점기반 위치 추정을 위한 모델을 제안한다. 실내 박물관이나 전시관과 같은 공간에서는 물체를 중심으로 위치기반서비스를 제공할 수 있기 때문에 사용자가 정확이 어떤 위치에 있는가 보다 어떤 물체에 가까이 있는지가 중요한 정보가 된다. 본 모델은 이러한 실내 공간을 고려하여 기점기반으로 영역을 정의하고 사용자의 위치를 상대적으로 추정한다. 이를 통해 기점기반 위치 추정은 기존의 좌표기반 위치 추정 보다 유연한 인프라 구축이 가능하고 사전 공간 정보가 필요 없는 장점을 가진다. 따라서 본 논문에서는 기점기반 위치 추정을 위한 알고리즘을 제안하고 실제 환경에서 이를 성능평가 한다. 그리고 실험 결과를 통해 본 논문에서 제안하는 기점기반 위치 추정이 효과적으로 사용자의 위치를 추정함을 확인할 수 있었다. In this paper, we propose a point-based location estimation model using WiFi signal. Because the indoor location-based service can be provided based on the objects, in indoor area such as museums or galleries, the information which object is close to a user is more important than the information where a user is. For such indoor environment, the proposed model defines the point-based area and relatively estimates the user location. Through this mechanism, the proposed model has advantages; proposed mechanism is flexible infrastructure and can not require pre-spatial information in comparison to axis-based location estimation. Therefore, in this paper, we design the algorithm for point-based location estimation model and measures performance evaluation in the real environment. Through experimental results, we knew that our point-based algorithm could efficiently estimate the user location.

3자유도 구형관절 운동기기의 위치 해석

김선필 경주대학교 정보전자기술연구소 2008 情報電子技術論叢 Vol.7 No.-

This paper investigates the position analysis of a spherical three degree of freedom parallel joint module, which is used in the exercise equipment for balance and leg-strength improvement of aged people. The joint module has three link chains which consists of two links and three revolute joints, and its all joints intersect at the global point located at the module's center. The paper shows the explicit mathematical procedure for deriving the closed form solutions in the inverse and forward position analysis of this parallel joint module.