• 한국가정과학회지
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• 제1권2호
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• pp.113-118
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• 1998

Clothing shape is principally described in seven factors that are composed of clothing design, clothing material, clothing size, pattern design, sewing method and body motion etc.. The aims of this study was to measurement out-line space-shape variation of clothing fitness with somato type by using the image processing. The subjects for direct anthropometric measurements were 248 female college students aged from 19 to 22. The data were statistically analyzed by principal analysis and cluster analysis. The results were obtained three somato type. Also I made skirts in order to analyzed to the out-line space-shape variation of clothing fitness with body. The effect of somato type on the shape of flare skirts was determined by the out-line space-shape variation of clothing fitness with body. The out-line space-shape variation of clothing fitness with body was observed between the node number and amplitudes of clothing wave form and node number was determined at the maxim of space-shape amplitude, and the space-shape amplitudes have related with aspect ratio of cross-sectional shape. Results for flare skirts show changes in amplitude and mean with fabrics, somato type. therefore gray-level histogram are correlated with changes out-line space-shape, differences in drape spacing and related fabric properties and their somato type. (Korean J Human Ecology 1(2):113∼110 1998)

• 한국가정과학회지
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• 제2권1호
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• pp.110-113
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• 1999

Clothing shape is principally described in seven factors that are composed of clothing design, clothing material, clothing size, pattern design, sewing method and body motion etc. The aims of this study was to measurement out-line space-shape variation of clothing fitness with body by using the image processing. The subjects for direct anthropometric measurements were 248 female college students aged from 19 to 22. The data were statistically analyzed by principal analysis and cluster analysis. The results selected one somatotype. for the out-line space-shape variation of clothing fitness with body, there dimensional clothing shapes measured. and cross-sectional clothing shape obtained by the measurement was considered to be space wave form. The out-line space-shape variation of clothing fitness with body was observed between the node number and amplitudes of clothing wave form, and node number was determined at the maxim of space-shape amplitude, and the space-shape amplitudes have related with aspect ratio of cross-sectional shape. (Korean J of Human Ecology 2(1) :110-113, 1999)

• International Journal of Aeronautical and Space Sciences
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• 제7권1호
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• pp.137-147
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• 2006

In this study, shape memory alloy damper with characteristics of pseudoelastic hysteresis for helicopter rotor blades are investigated. SMAs can be available in damping augmentation of vibrating structures. SMAs show large hysteresis in the process of pseudoelastic austenite-martensite phase transformation which takes place while subjected to loading above the austenite finish temperature. Since SMAs display pseudoelastic hysteresis behavior over large strain ranges, a significant amount of energy dissipation is possible. A damper can be designed with SMA wires prestressed to a baseline level somewhere in the middle of the pseudoelastic stress range. An experimental study of the effects of pre-strain and cyclic strain amplitude as well as frequency on the damping behavior of pseudoelastic shape memory alloy wires are performed. The effects of the shape memory alloy damper on aeroelastic and ground resonance stability of helicopter are studied. In aeroelastic stability, the dynamic characteristics of blades related to pitch angle and the amplitude of lag motion for the rotor equipped with SMA damper were examined. The performance of SMA damper on ground resonance instability are presented through the frequencies and modal damping with respect to rotating speed.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2003년도 한국우주과학회보 제12권2호
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• pp.24-24
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• 2003

We present preliminary results about the quasi-simultaneous near-infrared light curves of the long-period eclipsing polar V1309 Ori in the J, H, K', and K bands with almost complete orbital phase coverage using the CFHT-IR camera. The optical light curve in the V and R bands, obtained by 1.8m Telescope at BOAO, will be also presented. The shape and the amplitude of the orbital light curve change significantly from optical to near-infrared wavelengths.

• 천문학논총
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• 제20권1호
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• pp.49-53
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• 2005

We are often faced with the task of having to estimate the amplitude of a source signal in the presence of a background. In the simplest case, the background can be taken as being flat, and of unknown magnitude B, and the source signal of interest assumed to be the amplitude A of a peak of known shape and position. We present a robust method to find the most probable values of A and B by applying the one-dimensional Newton-Raphson method. In the derivation of the formula, we adopted the Bayesian statistics and assmumed Poisson distribution so that the results could be applied to the analysis of very weak signals, as observed in FIMS (Far-ultraviolet IMaging Spectrogaph).

• 천문학회보
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• 제44권1호
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• pp.53.2-53.2
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• 2019

$H{\alpha}$ surges (i.e. cool/dense collimated plasma ejections) may act as a guide for a propagation of magnetohydrodynamic waves. We report a high-resolution observation of a surge observed with 1.6m Goody Solar Telescope (GST) on 2009 August 26, from 18:20~UT to 18:45UT. Characteristics of plasma motions in the surge are determined with the normalizing radial gradient filter and the Fourier motion filter. The shape of the surge is found to change from a 'C' shape to an inverse 'C' shape after a formation of a cusp, a signature of reconnection. There are apparent upflows seen above the cusp top and downflows below it. The upflows show rising and rotational motions in the right-hand direction, with the rotational speed decreasing with height. Near the cusp top, we find a transverse oscillation of the surge, with the period of ~2 min. There is no change of the oscillation phase below the cusp top, but above the top a phase change is identified, giving a vertical phase speed about 86kms-1. As the height increases, the initial amplitude of the oscillation increases, and the oscillation damping time decreases from 5.13 to 1.18min. We conclude that the oscillation is a propagating kink wave that is possibly excited by an x-point oscillation.

• 천문학회보
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• 제44권1호
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• pp.80.1-80.1
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• 2019

Photometric investigations of asteroids allow us to determine their rotation states and shape models (Apostolovska et al. 2014). Our main target, asteroid (2078) Nanking's perihelion distance (q) is 1.480 AU, which belongs to the Mars-crossing asteroid (1.3 < q < 1.66 AU). Mars-crossing asteroids are objects that cross the orbit of Mars and regarded as one of the primary sources of near-Earth asteroids due to the unstable nature of their orbits. We present the analysis of the spin parameters and 3D shape model of (2078) Nanking. We conducted Cousins_R-band time-series photometry of this asteroid from November 26, 2014 to January 17, 2015 at the Sobaeksan Optical Astronomy Observatory (SOAO) and for 25 nights from March to April 2016 using the Korea Microlensing Telescope Network (KMTNet) to reconstruct its physical model with our dense photometric datasets. Using the lightcurve inversion method (Kaasalainen & Torppa 2001; Kaasalainen et al. 2001), we determine the pole orientation and shape model of this object based on our lightcurves along with the archival data obtained from the literatures. We derived rotational period of 6.461 h, the preliminary ecliptic longitude (${\lambda}_p$) and latitude (${\beta}_p$) of its pole as ${\lambda}_p{\sim}8^{\circ}$ and ${\beta}_p{\sim}-52^{\circ}$ which indicates a retrograde rotation of the body. From the apparent W UMa-shaped lightcurve and its location in the rotation frequency-amplitude plot of Sheppard and Jewitt (2004), we suspect the contact binary nature of the body (Choi 2016).

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.256-261
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• 2004

To evaluate the effect of spring shape on the fretting wear of nuclear fuel rod, sliding wear tests were performed using three kinds of space grid springs in room temperature air and water. With increasing slip amplitude, wear volume of each spring gradually increased. It is apparently shown that spring with convex shape had a relatively high wear resistance compared with concave shape springs. It is suggested that the ratio of the wear volume to the worn area can be suggested as an efficient and valid parameter to evaluate the wear resistibility of a fuel grid spring.

• 한국지구과학회지
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• 제28권4호
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• pp.491-496
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• 2007

소백산 천문대의 0.6m 광학망원경과 2K CCD 카메라를 이용하여 소행성 55 Pandora에 대한 R 필터 시계열 측광관측을 수행하였다. 관측으로부터 소행성의 자전 주기($P=4.^h8168$)와 진폭(${\Delta}R=0.281{\pm}0.001$란 구하였고, Amplitude-Magnitude 방법을 이용하여, 소행성 55 Pandora의 자전축 방향 ${\lambda}_p((^o)=342$, ${\beta}_p(^o)=64$와 세 축의 비는 a/b=1.27, b/c=1.31인 형태로 자전하고 있음을 알아내었다.

• International Journal of Aeronautical and Space Sciences
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• 제12권2호
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• pp.134-148
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• 2011

In general, forces acting on aerospace structures can be divided into two categories-a) conservative forces and b) nonconservative forces. Aeroelastic effects occur due to highly flexible nature of the structure, coupled with the unsteady aerodynamic forces, causing unbounded static deflection (divergence) and dynamic oscillations (flutter). Flexible wing panels subjected to jet thrust and missile type of structures under end rocket thrust are nonconservative systems. Here the structural elements are subjected to follower kind of forces; as the end thrust follow the deformed shape of the flexible structure. When a structure is under a constant follower force whose direction changes according to the deformation of the structure, it may undergo static instability (divergence) where transverse natural frequencies merge into zero and dynamic instability (flutter), where two natural frequencies coincide with each other resulting in the amplitude of vibration growing without bound. However, when the follower forces are pulsating in nature, another kind of dynamic instability is also seen. If certain conditions are satisfied between the driving frequency and the transverse natural frequency, then dynamic instability called 'parametric resonance' occurs and the amplitude of transverse vibration increases without bound. The present review paper will discuss the aeroelastic behaviour of aerospace structures under nonconservative forces.