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Detectability Test of H2 Lyman-Werner Band Emission for Far-Ultraviolet Imaging Spectrograph, FIMS
선광일,경욱 민,광선 유,대희 이,수종 박,승한 오,용선 박,용하 김,욱원 남,한원용,인수 육,장현 박,종호 신,호진,Eric J. Korpela,Jerry Edelstein,Kaori Nishikida 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.43 No.42
Molecular hydrogen (H2) is excited by far-ultraviolet (far-UV) photons and emits uorescent emission in the far-UV bands and in the near- and the mid-infrared bands. Observations of H2 in these photodissociation regions (PDRs) are important in tracing star-forming molecular clouds and in understanding the interaction between newly born stars and molecular clouds. We use the typical PDR model of Sternberg to estimate the observing time (or integration time) required to detect PDRs with the Far-ultraviolet IMaging spectrograph (FIMS) onboard KAISTSAT-4, the rst Korean scientic satellite. The observing time is calculated using a formula based on a rigorous hypothesis testing for the detection limit, in contract to the often-used signal-to-noise ratio. The estimated observing time is also compared with the expected exposure time from one-year all-sky survey.
Knee Air Bag 전개를 고려한 Knee Bolster System 최적화 연구
선광상(Kwangsang Seon),방선호(Sunho Bang),박상근(Sangkeun Park),김용석(Yongsuk Kim) 한국자동차공학회 2014 한국자동차공학회 학술대회 및 전시회 Vol.2014 No.11
automotive industry has steadily tried to reduce the Vehicle weight to improve fuel. there have been studied aiming at reducing weight by changing thickness or new lightweight material. in this study, we took both thickness and material arrangement as design variables to enhance reducing the weight. this study suggest optimized knee bloster system concept model considering FMVSS208 regulation with Air Bag Module Bracket stiffness without mass increase. design factor, are selected and the intersection is evaluated among design factors using function analysis of DFSS. multi-disciplinary optimization process is conducted to get the optimal design. the validation runs are carried over to achieve the resonable design solution to implement the optimal solution to the physical vehicle proprietary optimization tool.
Chebychev 항등식과 Bessel 계수를 이용한 지수펄스모형함수 생성 및 특성
이정재,박선광,Lee, Jeong-Jae,Park, Sun-Kwang 한국융합신호처리학회 2009 융합신호처리학회 논문지 (JISPS) Vol.10 No.1
본 논문에서는 Chebychev 항등식과 Bessel 계수로부터 유도 될 수 있는 새로운 지수펄스모형함수를 제안하고 그 특성을 고찰한다. 제안된 지수펄스모형함수는 매개변수 변화에 따라 시간과 주파수영역에서 서로 다른 특성을 갖는 다양한 펄스 모형함수를 발생시킬 수 있다. 그리고 지수펄스모형함수의 미분함수로부터 여러 형태를 갖는 새로운 펄스모형함수를 얻을 수 있다. 미분으로부터 얻어지는 지수펄스함수의 짝수 계와 홀수 계 미분 함수간은 직교성을 유지한다. 이러한 기본적인 특성을 통상적인 Gaussian 펄스 모형함수와 비교 분석함으로써 그 유용성을 확인한다. 통신시스템의 요구 설계조건에 따라 최적의 지수펄스파형을 선택하여 사용할 수 있다. In this paper, we propose a new exponential pulse shaping function based on Chebychev identity equation and Bessel coefficients. The proposed pulse shaping function can produce various pulses with the different characteristics in the time and frequency domain by changing its two parameters. By differentiating the exponential pulse shaping function, we obtain new different pulse functions, in which the even order derivatives of the exponential pulse shaping function are orthogonal to its odd order derivatives. To find the efficiency of the proposed exponential pulse shaping function we analyze its essential characteristics and compare them with those of the conventional Gaussian pulses. We can choose the most suitable exponential pulse waveform according to the design criteria of communication systems.
Gap/Flush 품질 개선을 위한 Fascia support bracket 형상 optimization study
조현성(Hyunsung Jo),선광상(Kwangsang Seon),박상근(Sangkeun Park) 한국자동차공학회 2018 한국자동차공학회 학술대회 및 전시회 Vol.2018 No.11
In designing vehicles, the finish is always quality control, and it is no exaggeration to say that quality sells vehicles. One of the important factors that determines its quality is Gap/Flush management. The gap between Body-In-White parts consisting of steel or aluminum and exterior parts consisting of plastic is a directly visible area in the eyes of consumer. It should be consistent and has almost no gap. In particular, the front fascia in front of the body, which consists of a weak and large plastic parts, can be occurred sagging by weight of itself, and thus some system is needed to prevent this deflection and to match with Body-In-White parts. Screw jack is the system attached to the fascia support bracket. Tightening screw jack makes touching to the golden bracket, which is just blow and has relatively strong stiffness. Then, continuing tightening screw jack will lift the fascia support bracket, which has relatively weak stiffness, and raise the fascia parts on it, so preventing the entire front fascia from sagging. After all, tightening and loosening the screw jack will allows front fascia to adjust its deflection. In this paper, we conducted a DFSS project to improve front fascia deflection control system of screw jack through optimizing the shape of fascia support bracket. In addition, we performed test for comparing with CAE analysis and verifying the improved performance of screw jack.
PRELIMINARY FEASIBILITY STUDY OF THE SOLAR OBSERVATION PAYLOADS FOR STSAT-CLASS SATELLITES
Yong-Jae Moon,채종철,조경석,진호,이성호,박영득,선광일,김연한 한국우주과학회 2004 Journal of Astronomy and Space Sciences Vol.21 No.4
In this paper, we present preliminary feasibility studies on three types of solar observation payloads for future Korean Science and Technology Satellite (STSAT) programs. The three candidates are (1) an UV imaging telescope, (2) an UV spectrograph, and (3) an X-ray spectrometer. In the case of UV imaging telescope, the most important constraint seems to be the control stability of a satellite in order to obtain a reasonably good spatial resolution. Considering that the current pointing stability estimated from the data of the Far ultraviolet Imaging Spectrograph (FIMS) onboard the Korean STSAT-1, is around 1 arc minutes/sec, we think that it is hard to obtain a spatial resolution sufficient for scientific research by such an UV Imaging Telescope. For solar imaging missions, we realize that an image stabilization system, which is composed of a small guide telescope with limb sensor and a servo controller of secondary mirror, is quite essential for a very good pointing stability of about 0.1 arcsec. An UV spectrograph covering the solar full disk seems to be a good choice in that there is no risk due to poor pointing stability as well as that it can provide us with valuable UV spectral irradiance data valuable for studying their effects on the Earth's atmosphere and satellites. The heritage of the FIMS can be a great advantage of developing the UV spectrograph. Its main disadvantage is that two major missions are in operation or scheduled. Our preliminary investigations show that an X-ray spectrometer for the full disk Sun seems to be the best choice among the three candidates. The reasons are : (1) high temporal and spectral X-ray data are very essential for studying the acceleration process of energetic particles associated with solar flares, (2) we have a good heritage of X-ray detectors including a rocket-borne X-ray detector, (3) in the case of developing countries such as India and Czech, solar X-ray spectrometers were selected as their early stage satellite missions due to their poor pointing stabilities, and (4) there is no planned major mission after currently operating Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) mission. Finally, we present a preliminary design of a solar X-ray spectrometer covering soft X-ray (2 keV) to gamma ray (10 MeV).
모드 해석 방법의 절차 개발 과정 소개 및 해석 결과 비교 (MODAL, FRF, KE)
조현성(Hyunsung Jo),최재영(Jaeyoung Choi),선광상(Kwangsang Seon),박상근(Sangkeun Park) 한국자동차공학회 2022 한국자동차공학회 부문종합 학술대회 Vol.2022 No.6
During vehicle structural analysis with CAE (Computer Aided Engineering) method using FEM (Finite Element Method), the first one is the MODAL analysis. For the detail of MODAL analysis, I will explain at main chapter. The more Degree of Freedom is used in MODAL analysis, The more real flexible body motion, it have. But it needs to use more memory for the process of analysis. So, in commercial program, the Lanczos method is preferred for proceeding of mode analysis with quickly and efficiently. Using this method, it is possible to set the desired frequency interval and it can specify the number of modes you want to see. Especially, it is possible to view and evaluate natural frequency values from low-order modes such as First mode and Second mode, which are the main interests of the user, and dynamic behavior in that mode in a short time. However, as the number of parts used in the analysis model increases, it is difficult to find an accurate mode value only in the region of interest. This is because the modes of multiple parts come together with the same mode value. Especially, if the dynamic behavior you want to see is a vibration caused by a specific part, mode analysis alone is not enough. Therefore, the FRF (Frequency Response Function) method is used, which is easy to see the behavior of a particular mode of interest only, but cannot see the dynamic behavior of the mode, and it is impossible to numerically compare exactly what percentage of the mode of the desired part. Therefore, the KE (Kinetic Energy) method is used which shows exactly how much percentage each part accounts for in each mode in total mode, so it is easy to find the desired mode, and then, through mode analysis, it is possible to immediately check whether it is the desired mode or not. Therefore, in the end, for accurate mode analysis, it was previously evaluated in only one method through MODAL analysis, but now all three additional methods need to be analyzed.