• International Journal of Fuzzy Logic and Intelligent Systems
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• 제13권2호
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• pp.124-132
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• 2013

This study investigated the feasibility of gait recognition using points on the body in three-dimensional (3D) space based on comparisons of four different feature vectors. To obtain the point trajectories on the body in 3D, gait motion data were captured from 10 participants using a 3D motion capture system, and four shoes with different heel heights were used to study the effects of heel height on gait recognition. Finally, the recognition rates were compared using four methods and different heel heights.

• 한국의류학회지
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• 제19권2호
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• pp.366-379
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• 1995

This study was performed to provide fundamental data on middle-aged women's upper torso by classifying the upper torso somatotype and analyzing the characteristics of their somatotype. Factor analysis of principal component model was used to 38 directly measured items, and cluster analysis was applied for classification of upper torso forms. Seven factors were extracted from the factor analysis. The first factor represented the items of circumference, breadth, and depth which were related with body size. On the basis of the cluster analysis using factor scores trom factor analysis as being independent variables, the subjects were classified into three groups. Three dress forms were constructed according to the characteristics for each somatotype of subjects, the three-dimensional characteristics of somatotype were analyzied by the moire pattern and horizontal section map of proposed dress forms. Wearing test by moire topography was used to evaluate wearing outline, the ease of clothes and garment space. Moire pattern and horizontal section map were useful to evaluate wearing conditions, and garment space was changed by the characteristics of the body shape.

• Journal of Astronomy and Space Sciences
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• 제33권3호
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• pp.167-172
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• 2016

We used the 4 m Discovery Channel Telescope (DCT) at Lowell observatory in 2014 to observe the Guitar Nebula, an Hα bow-shock nebula around the high-velocity radio pulsar B2224+65. Since the nebula's discovery in 1992, the structure of the bow-shock has undergone significant dynamical changes. We have observed the limb structure, targeting the "body" and "neck" of the guitar. Comparing the DCT observations to 1995 observations with the Palomar 200-inch Hale telescope, we found changes in both spatial structure and surface brightness in the tip, head, and body of the nebula.

• 한국항공우주학회지
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• 제40권3호
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• pp.193-200
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• 2012

스키점프 공력 특성에 관한 자료 획득을 목적으로 전산 수치 해석을 수행하였다. 한국인의 체형을 고려한 인체 모델링 기법을 적용하였으며 해석 결과의 검증을 위해 기존 풍동실험 연구 결과를 비교 분석하였다. 다양한 비행 조건에서 공력 계수를 분석하여 최대 양항비를 나타내는 비행 자세를 발견하였다. 본 연구가 대한민국 스키점프 선수들의 비행 자세 교정과 국내 스포츠 과학 발전에 기여할 수 있을 것으로 기대한다.

• International Journal of Aeronautical and Space Sciences
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• 제9권1호
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• pp.76-84
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• 2008

This paper is mainly concerned with the vision-based attitude stabilization of a quad-rotor UAV. The methods for attitude control rely on computing the roll and pitch angles of the vehicle from a two-camera vision system. One camera is attached to the body-fixed x-axis and the other to the body-fixed y-axis. The attitude computation for the quad-rotor UAV is performed by image processing consisting of Canny edge and Hough line detection. A proportional and integral controller is employed for the attitude hold autopilot. In this paper, the quad-rotor UAV is modeled by 6-DOF nonlinear equations of motion that includes rotor aerodynamics with blade element theory. The performance of the proposed method is evaluated through 3D environmental numerical simulations.

• International Journal of Aeronautical and Space Sciences
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• 제13권1호
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• pp.106-116
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• 2012

Optimal transfer trajectories based on the planar circular restricted three body problem are designed by using mixed impulsive and continuous thrust. Continuous and dynamic trajectory optimization is reformulated in the form of discrete optimization problem. This is done by the method of direct transcription and collocation. It is then solved by using nonlinear programming software. Two very different transfer trajectories can be obtained by the different combinations of the design parameters. Furthermore, it was found out that all designed trajectories permit a ballistic capture by the Moon's gravity. Finally, the required thrust profiles are presented and they are analyzed in detail.

• Journal of Multimedia Information System
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• 제6권2호
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• pp.99-106
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• 2019

In traditional Chinese medical (TCM) science, tongue images can be observed for medical diagnosis; however, the tongue diagnosis of TCM is influenced by the subjective factors of doctors, and the diagnosis results vary from person to person. Quantitative TCM tongue diagnosis can improve the accuracy of diagnosis and increase the application value. In this paper, digital image processing and pattern recognition technologies are employed on mobile device to classify tongue images collected in different health states. First, through grayscale integral projection processing, the trough is found to localize the tongue body. Then the tongue body image is transferred from RGB color space to HSV color space, and the average H and S values are considered as the color features. Finally, the diagnosis results are obtained according to the relationship between the color characteristics and physical symptoms.

• Journal of Astronomy and Space Sciences
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• 제40권1호
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• pp.29-33
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• 2023

An unexplained acceleration on the order of 10^-8 cm s^-2, which is close to cH, where c is the speed of light and H is the Hubble constant, is detected in gravitationally bound systems of different scales, from the solar system to clusters of galaxies. We found that any test body located inside a fractal structure with fractal dimension D = 2 experiences acceleration of the same order and confirmed the previous work that photons propagating through this structure decrease the frequency owing to gravitational redshift. The acceleration can be directed against the movement of the test body. The fractal distribution of the matter should be at scales of at least hundreds of megaparsecs to a few gigaparsecs for the existence of this acceleration.

• 천문학회보
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• 제46권1호
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• pp.58.1-58.1
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• 2021

At the University of Seoul, we are investigating the following topics in cosmology: comparing traditional clustering algorithms to our new Mulguishin algorithms, analysis of 2-body Fuzzy Dark Matter 2-body collision, 2- and 3-point clustering statistics and its dependency on the cosmological model, and dynamics of dark-matter halos around the large-scale filamentary structures. In the following sections we present a brief introduction to our studies.

• International Journal of Aeronautical and Space Sciences
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• 제13권3호
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• pp.386-397
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• 2012

The stability and structure of bluff-body stabilized hydrogen flames were investigated numerically and experimentally. The velocity of coflowing air was varied from subsonic velocity to a supersonic velocity of Mach 1.8. OH PLIF images and Schlieren images were used for analysis. Flame regimes were used to classify the characteristic flame modes according to the variation of the fuel-air velocity ratio, into jet-like flame, central-jet-dominated flame, and recirculation zone flame. Stability curves were drawn to find the blowout regimes and to show the improvement in flame stability with increasing lip thickness of the fuel tube, which acts as a bluff-body. These curves collapse to a single line when the blowout curves are normalized by the size of the bluff-body. The variation of flame length with the increase in air flow rate was also investigated. In the subsonic coflow condition, the flame length decreased significantly, but in the supersonic coflow condition, the flame length increased slowly and finally reached a near-constant value. This phenomenon is attributed to the air-entrainment of subsonic flow and the compressibility effect of supersonic flow. The closed-tip recirculation zone flames in supersonic coflow had a reacting core in the partially premixed zone, where the fuel jet lost its momentum due to the high-pressure zone and followed the recirculation zone; this behavior resulted in the long characteristic time for the fuel-air mixing.