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An Analysis of Local Wind Field based on Urban Development (도시개발에 따른 국지 바람장 분석)

  • Song, Dong Woong
    • Journal of Environmental Impact Assessment
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    • v.20 no.2
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    • pp.133-140
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    • 2011
  • A numerical study with Envi-met model is experimented to investigate the characteristics of wind pattern in Gangwon innovation city. In all case, most conditions such as wind speed, temperature, and surface are considered as the same, but wind direction is the only different factor. The wind directions considered in this study have a meaning of prevailing wind direction. When the prevailing wind with the direction of $247^{\circ}$ blows into the city, the ventilation passage toward the outside of city is formed and the stagnation of air is not expressed. In case of having the direction of $270^{\circ}$, most evident ventilation passages are composed. When the inflow wind direction is the north, $0^{\circ}$, there is some possibility of stagnation phenomenon. The case where the representative wind direction of three kind will flow with development, in compliance with the building is caused by with screening effect of some and shows a true stagnation phenomenon, wishes in the park and flowing water and the greens area to be for a long time formed and the wind direction is maintained.

CME and radio characteristics of making large solar proton events

  • Hwang, Jung-A;Cho, Kyung-Suk;Bong, Su-Chan;Kim, Su-Jin;Park, Young-Deuk
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.1
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    • pp.33.2-33.2
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    • 2010
  • We have investigated a relationship among the solar proton events (SPEs), coronal mass ejections (CMEs) and solar flares during the solar cycle 23 (1997-2006). Using 63 SPE dataset, we found that SPE rise time, duration time, and decrease times depend on CME speed and SPE peak intensity depends on the CME earthward direction parameter as well as CME speed and x-ray flare intensity. While inspecting the relation between SPE peak intensity and the CME earthward direction parameter, we found that there are two groups: first group consists of large 6 SPEs (> 10,000 pfu at >10 MeV proton channel of GOES satellite) and shows a very good correlation (cc=0.65) between SPE peak intensity and CME earthward direction parameter. The second group has a relatively weak SPE peak intensity and shows poor correlation between SPE peak intensity and the CME earthward direction parameter (cc=0.01). By investigating characteristics of 6 SPEs in the first group, we found that there are special common conditions of the extremely large proton events (group 1); (1) all the SPEs are associated with very fast halo CME (>1400km/s), (2) they are almost located at disk region, (3) they also accompany large flare (>M7), (4) all they are preceded by another wide CMEs, and (5) they all show helmet streamer nearby the main CME. In this presentation, we will give details of the energy spectra of the 6 SPE events from the ERNE/HED aboard the Solar and Heliospheric Observatory (SOHO), and onset time comparison among the SPE, flare, type II burst, and CME.

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A Characteristics of Directional Orientation of the Houses on Sangas, Imha, Hawoosan, Walgok Traditional Villages of Geomantic North (북향형국(北向形局)의 전통마을에서 주택의 방위적(方位的) 특성에 관한 연구 - 상사, 임하, 하우산, 월곡 마을을 중심으로 -)

  • Lee, Hyun-Byung;Kim, Sung-Woo
    • Journal of architectural history
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    • v.18 no.3
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    • pp.27-44
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    • 2009
  • In Korea, the direction of houses are typically determined by considering the directional orientation and shape of the mountain range rather than ignoring the geographical feature of the mountain range. Traditional villages of Korea are known to have very particular ways of adopting the geomantic surroundings of natural environment. This is very true especially have a high mountain in the back and a lower mountain in front. At the same time, most of the houses tend to prefer south as a man direction so that they can receive more sun light. However, if the mountain range faces north, it will not be easy to determine the directional orientation of houses. This paper, therefore, tries to identify how the houses of villages facing north, direst the orientation. This, the northern village, solves the problem by facing all direction rather than one major direction. The houses of the villages facing north, tend to revise the direction by changing the back mountain(주산) or front mountain(인산) that helps them change the direction towards he range of eastern or western direction. As a result, the houses tend to the direction towards east and wes compared to north and south. The directional orientation of houses was clearly distributed or concentrated by depending of the shape and directional orientation of the mountain range. This kind of research let us know the relationship between the natural north direction, the direction of geomantic surrounding, and the direction of houses in traditional Korean villages.

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Rotation control for the Yaw-direction of Unicycle Robot (외바퀴 로봇의 Yaw 방향 회전 제어)

  • Hwang, Jong-Myung;Bae, Dong-Suck;Lee, Jang-Myung
    • The Journal of Korea Robotics Society
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    • v.3 no.4
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    • pp.331-337
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    • 2008
  • The field of robots is being widely accepted as a new technology today. Many robots are produced continuously to impart amusement to people. Especially the robot which operates with a wheelbarrow was enough of a work of art to arouse excitement in the audiences. All the wheelbarrow robots share the same technology in that the direction of roll and pitch are acting as balance controllers, allowing the robots to maintain balance for a long period by continuously moving forward and backward. However one disadvantage of this technology is that they cannot avoid obstacles in their way. Therefore movement in sideways is a necessity. For the control of rotation of yawing direction, the angle and direction of rotation are adjusted according to the velocity and torque of rotation of a motor. Therefore this study aimed to inquire into controlling yawing direction, which is responsible for rotation of a robot. This was followed by creating a simulation of a wheelbarrow robot and equipping the robot with a yawing direction controlling device in the center of the body so as to allow sideway movements.

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Serviceability evaluation methods for high-rise structures considering wind direction

  • Ryu, Hye-Jin;Shin, Dong-Hyeon;Ha, Young-Cheol
    • Wind and Structures
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    • v.30 no.3
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    • pp.275-288
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    • 2020
  • High-rise buildings are very slender and flexible. Their low stiffness values make them vulnerable to horizontal loads, such as those associated with wind or earthquakes. For high-rise buildings, the threat to serviceability caused by wind-induced vibration is an important problem. To estimate the serviceability under wind action, the response acceleration of a building at the roof height is used. The response acceleration is estimated by the same wind speed at all wind directions. In general, the effect of wind direction is not considered. Therefore, the response accelerations obtained are conservative. If buildings have typical plans and strong winds blow from relatively constant wind directions, it is necessary to account for the wind direction to estimate the response accelerations. This paper presents three methods of evaluating the response accelerations while considering the effects of wind direction. These three serviceability evaluation methods were estimated by combining the wind directional frequency data obtained from a weather station with the results of a response analysis using wind tunnel tests. Finally, the decrease in the efficiencies of the response acceleration for each serviceability evaluation method was investigated by comparing the response acceleration for the three methods accounting for wind direction with the response acceleration in which wind direction was not considered.

Body Image of Stripe Design Variations in Semi-tight Skirt (세미 타이트 스커트의 스트라이프 디자인 변화에 따른 신체 이미지)

  • Lim, Hea-Lyong;Uh, Mi-Kyung
    • Journal of the Korea Fashion and Costume Design Association
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    • v.17 no.2
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    • pp.145-154
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    • 2015
  • This study aims to identify the differences of body image when the stripe direction and width change of semi-tight skirt. The semi-tight skirt pattern was made using the standard size of a women in their 20s. 12 semi-tight skirt models combining 6 kinds of stripe directions and 2 kinds of stripe widths were made using CLO 3D virtual clothing system. The data was evaluated by 126 fashion design majors. The results were as follows; In accordance with the body image factor analysis of semi-tight skirt, three image factors were identified; whole body optical illusion, calf optical illusion and hip optical illusion. Among these factors, the whole body optical illusion factor is the most important factor. The body image depending on the stripe direction and width change of semi-tight skirt mostly showed the significant difference. In accordance with the analysis on the interaction effect of body image depending on the stripe direction and width change of semi-tight skirt, the whole body, calf and hip optical illusion factors showed the significance. The interaction of body image had independent influence on all factors of stripe direction and width. In particular, the interaction of stripe direction and width had the most significant influence on the whole body optical illusion.

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A Combination Method of Trajectory Data using Correlated Direction of Collected GPS Data (수집한 GPS데이터의 상호방향성을 이용한 경로데이터 조합방법)

  • Koo, Kwang Min;Park, Heemin
    • Journal of Korea Multimedia Society
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    • v.19 no.8
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    • pp.1636-1645
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    • 2016
  • In navigation systems that use collected trajectory for routing, the number and diversity of trajectory data are crucial despite the infeasible limitation which is that all routes should be collected in person. This paper suggests an algorithm combining trajectories only by collected GPS data and generating new routes for solving this problem. Using distance between two trajectories, the algorithm estimates road intersection, in which it also predicts the correlated direction of them with geographical coordinates and makes a decision to combine them by the correlated direction. With combined and generated trajectory data, this combination way allows trajectory-based navigation to guide more and better routes. In our study, this solution has been introduced. However, the ways in which correlated direction is decided and post-process works have been revised to use the sequential pattern of triangles' area GPS information between two trajectories makes in road intersection and intersection among sets comprised of GPS points. This, as a result, reduces unnecessary combinations resulting redundant outputs and enhances the accuracy of estimating correlated direction than before.

Geolocation Error Analysis of KOMPSAT-5 SAR Imagery Using Monte-Carlo Simulation Method

  • Choi, Yoon Jo;Hong, Seung Hwan;Sohn, Hong Gyoo
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.37 no.2
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    • pp.71-79
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    • 2019
  • Geolocation accuracy is one of the important factors in utilizing all weather available SAR satellite imagery. In this study, an error budget analysis was performed on key variables affecting on geolocation accuracy by generating KOMPSAT-5 simulation data. To perform the analysis, a Range-Doppler model was applied as a geometric model of the SAR imagery. The results show that the geolocation errors in satellite position and velocity are linearly related to the biases in the azimuth and range direction. With 0.03cm/s satellite velocity biases, the simulated errors were up to 0.054 pixels and 0.0047 pixels in the azimuth and range direction, and it implies that the geolocation accuracy is sensitive in the azimuth direction. Moreover, while the clock drift causes a geolocation error in the azimuth direction, a signal delay causes in the range direction. Monte-Carlo simulation analysis was performed to analyze the influence of multiple geometric error sources, and the simulated error was up to 3.02 pixels in the azimuth direction.

The Effects of Gaze Direction on the Stability and Coordination of the Lower Limb Joint during Drop-Landing (드롭랜딩 시 시선 방향의 차이가 하지관절의 안정성과 협응에 미치는 영향)

  • Kim, Kewwan;Ahn, Seji
    • Korean Journal of Applied Biomechanics
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    • v.31 no.2
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    • pp.126-132
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    • 2021
  • Objective: The purpose of this study was to investigate how three gaze directions (bottom, normal, up) affects the coordination and stability of the lower limb during drop landing. Method: 20 female adults (age: 21.1±1.1 yrs, height: 165.7±6.2 cm, weight: 59.4±5.9 kg) participated in this study. Participants performed single-leg drop landing task on a 30 cm height and 20 cm horizontal distance away from the force plate. Kinetic and kinematic data were obtained using 8 motion capture cameras and 1 force plates and leg stiffness, loading rate, DPSI were calculated. All statistical analyses were computed by using SPSS 25.0 program. One-way repeated ANOVA was used to compared the differences between the variables in the direction of gaze. To locate the differences, Bonferroni post hoc was applied if significance was observed. Results: The hip flexion angle and ankle plantar flexion angle were significantly smaller when the gaze direction was up. In the kinetic variables, when the gaze direction was up, the loading rate and DPSI were significantly higher than those of other gaze directions. Conclusion: Our results indicated that decreased hip and ankle flexion angles, increased loading rate and DPSI when the gaze direction was up. This suggests that the difference in visual information can increase the risk of injury to the lower limb during landing.

Processing of Vermiculite-Silica Composites with Prefer-Oriented Rod-Like Pores

  • Eom, Jung-Hye;Kim, Young-Wook;Lee, Seung-Seok;Jeong, Doo-Hoa
    • Journal of the Korean Ceramic Society
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    • v.49 no.4
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    • pp.347-351
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    • 2012
  • Vermiculite-silica composites with a layered structure were fabricated by adding cellulose fibers as a pore former and by a simple uniaxial pressing and subsequent sintering process. Three different combinations of additives were used and their effects on the compressive strength and thermal conductivity of the composites were investigated. Both compressive strengths (42-128 MPa) and thermal conductivities (0.75-1.48 $W/m{\cdot}K$) in the direction perpendicular to the pressing direction (T) were higher than those (19-81 MPa and 0.32-1.04 $W/m{\cdot}K$) in the direction parallel to the pressing direction (S) in all samples. The anisotropy in both properties was attributed to the microstructural anisotropy, which was caused by the layered structure developed in the composites.