• Title/Summary/Keyword: 순간속도중심

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The Analysis of Instantaneous $CO_2$ Uptake and Evapotranspiration of Herbaceous Plants for Artificial Roof Greening (옥상녹화용 초본식물의 순간 $CO_2$ 흡수 및 증발산량 분석)

  • Ahn, Geun-Young;Han, Seung-Won;Lee, Eun-Heui
    • Korean Journal of Environment and Ecology
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    • v.25 no.1
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    • pp.91-101
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    • 2011
  • The purpose of this study is to demonstrate the positive effects of artificial ground greening on the reduction of carbon dioxide ($CO_2$) which can help improve ecological functions in cities and mitigation of climate change, through quantifying $CO_2$ uptake and evapotranspiration by the process of photosynthesis of some plants. Experiment of $CO_2$ uptake and evapotranspiration was conducted by measurement of $CO_2$ exchange rate using the infrared gas analyzer, for 7 month, growing season from May to November 2009, 2 times a month. The result was as follows; The $CO_2$ uptake quantity per $cm^2$ of Chrysanthemum zawadskii was the highest rate at $21.47{\times}10^{-6}g/cm^2/s$ and Poa pratensis was $16.20g{\times}10^{-6}g/cm^2/s$. The stronger was light of intensity, the higher were $CO_2$ uptake rate of most plants. In quantity of evapotranspiration, Poa pratensis was the highest rate at $8.75{\times}10^{-5}g/cm^2/s$ and Aquilegia buergariana was $8.66{\times}10^{-5}g/cm^2/s$. From this study, it is confirmed that artificial ground greening has capacity of absorption $CO_2$ and effects on improving urban microclimate.

A Case Study of Tkatchev stretched Motion by Technical Feedback in Horizontal Bars (기술처치에 의한 철봉 Tkatchev stretched 동작의 사례연구)

  • Back, Jin-Ho;Son, Won-Il
    • Korean Journal of Applied Biomechanics
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    • v.18 no.4
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    • pp.77-87
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    • 2008
  • This study is to formulate strategy for subject who are selected as national team in horizontal bars event in apparatus gymnastics. For this, skill training program was applied to players for 8 weeks. Then it was analyzed by using 3D motion Analysis system to seek the difference between before and after using the program. There were decisive demerit element K's first try for Tkatchev stretched movement from low elevation and crooked body while elevating. Not only, the location of his center of mass is far and low and there was some concern in his landing due to bended his hip-joint, but also, it exposed weak point in retro-action followed technique. Thus, to overcome that weak point, the subject repeated practices on following; when preparing for Tkatchev stretched movement at downward for big spin, make sure extend shoulder angle faster, make sure Tap movement is short and concise using hip-joint angular while delaying Tap timing for folding the body, and moreover, while backlashing the body, used shoulder joint angle wide to pull up the body. As a result, the speed of vertical upward did rut increase when separation from the bar. However, height of elevation increased that the leg would rut hit the horizontal bar even straight up the hip-joint. Therefore, the movement itself provided magnificent motion and even helped decrease the demerits.

Numerical Study of Evaporation and Ignition of in-line Array Liquid Droplets (액적 배열의 증발과 착화에 관한 수치해석적 연구)

  • 김충익;송기훈
    • Fire Science and Engineering
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    • v.13 no.1
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    • pp.37-47
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    • 1999
  • The spreading fire of very small floating particles after they are ignited is fast and t therefore dangerous. The research on this area has been limited to experiments and global simulations which treat them as dusts or gaseous fuel with certain concentration well m mixed with air. This research attempted micro-scale analysis of ignition of those particles modeling them as liquid droplets. For the beginning, the in-line array of fuel droplets is modeled by two-dimensional, unsteady conservation equations for mass, momentum, energy and species transport in the gas phase and an unsteady energy equation in the liquid phase. They are solved numerically in a generalized non-orthogonal coordinate. The single step chemical reaction with reaction rate controlled by Arrhenius’ law is assumed to a assess chemical reaction numerically. The calculated results show the variation of temperature and the concentration profile with time during evaporation and ignition process. Surrounding oxygen starts to mix with evaporating fuel vapor from the droplet. When the ignition condition is met, the exothermic reactions of the premixed gas initiate a and burn intensely. The maximum temperature position gradually approaches the droplet surface and maximum temperature increases rapidly following the ignition. The fuel and oxygen concentration distributions have minimum points near the peak temperature position. Therefore the moment of ignition seems to have a premixed-flame aspect. After this very short transient period minimum points are observed in the oxygen and fuel d distributions and the diffusion flame is established. The distance between droplets is an important parameter. Starting from far-away apart, when the distance between droplets decreases, the ignition-delay time decreases meaning faster ignition. When they are close and after the ignition, the maximum temperature moves away from the center line of the in-line array. It means that the oxygen at the center line is consumed rapidly and further supply is blocked by the flame. The study helped the understanding of the ignition of d droplet array and opened the possibility of further research.

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Effect of Salinity-stratified Waters on Upward Migration and Ratio of Extracted DNA/RNA in Cochlodinium polykrikoides Margalef Based on the Ratio of Absorbance at 260 and 280nm (염분 구배가 Cochlodinium polykrikoides Margalef의 수직이동 및 DNA/RNA 비율에 미치는 영향)

  • Cho Eun Seob;Lee Young Sik
    • Journal of Life Science
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    • v.15 no.3 s.70
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    • pp.468-473
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    • 2005
  • The coastal regions of Yeosu, the South Sea of Korea, has occurred annually the red tide which is caused by potentially ichthyotoxic dinoflagellate C. polykrikoides, with a wide avenue for exchange with oceanic waters and freshwater runoff from Sumjin river. We attempted to examine the variability in response to vertical migration and concentration of extracted DNA/RNA of C. polykrikoides exposed to salinity-stratified waters. The experimental aquarium of the 60 liter was employed to culture C. polykrikoides. One aquarium was supplied with only sea water, the other was consisted of sea water and freshwater. Experiment was conducted for 5 days. In experimental column (mixture of freshwater and sea water), salinity was maintained to 20 at upper and approximately 30 at bottom during the period of this study. The fluctuation with related to dissolved oxygen and pH was similar pattern to both columns. Chlorophyll a was significantly higher value at upper than bottom. During 24h, chlorphyll a on experimental column was extremely high on the top as soon as lighting, compared with control. With elapsed time, the gap between experimental and control columns was a little. In darkness, chlorophyll a was not significantly different between upper and bottom, most cells appeared to randomly distribute on column regardless of water layer. Fluctuation with related to concentration of extracted DNA and RNA based on ratio of absorbance of 260 and 280 nm in experimental column was higher at final day or diel migration than control. These results implied that a large volume of freshwater could be associated with influence of concentration of DNA and RNA, in particular, rapid upward movement caused massive fish kills as soon as sunset.

Sports Biomechanical Analysis of Physical Movements on the Basis of the Patterns of the Ready Poses (준비동작의 형태 변화에 따른 신체 움직임의 운동역학적 분석)

  • Lee, Joong-Sook
    • Korean Journal of Applied Biomechanics
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    • v.12 no.2
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    • pp.179-195
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    • 2002
  • The purpose of this research is to provide a proper model by analyzing the sports biomechanical of physical movements on the basis of the two patterns(open-stance and cross-stance) at the ready-to-start pose. The subjects for this study are composed of five male handball players from P university and five female shooting players from S university. Three-way moving actions at start(right, left, and forward) are recorded with two high-speed video cameras and measured with two Force platforms and a EMG system. Three-dimensional action analyzer, GRF system, and Whole body reaction movement system are used to figure out the moving mechanisms at the start pose. The analytic results of the moving mechanism at the start pose were as follows. 1. Through examining the three-way moving actions at start, I have found the cross-stance pose is better for the moving speed of body weight balance than the open-stance one. 175 degree of knee joint angle at "take-off" and 172 degree of hip joint angle were best for the start pose. 2. The Support time and GRF data shows that the quickest center of gravity shift was occurred when cross-stanced male subjects started to move toward his lefthand side. The quickest male's average supporting time of left and right foot is 0.19${\pm}$0.07 sec., 0.26${\pm}$0.06sec. respectively. The supporting time difference between two feet is 0.07sec. 3. Through analyzing GRF of moving actions at start pose, I have concluded that more than 1550N are overloaded on one foot at the open-stance start, and the overloaded force may cause physical injury. However, at the cross-stance pose, The GRF are properly dispersed on both feet, and maximum 1350N are loaded on one foot.

A Simulation-Based Investigation of an Advanced Traveler Information System with V2V in Urban Network (시뮬레이션기법을 통한 차량 간 통신을 이용한 첨단교통정보시스템의 효과 분석 (도시 도로망을 중심으로))

  • Kim, Hoe-Kyoung
    • Journal of Korean Society of Transportation
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    • v.29 no.5
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    • pp.121-138
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    • 2011
  • More affordable and available cutting-edge technologies (e.g., wireless vehicle communication) are regarded as a possible alternative to the fixed infrastructure-based traffic information system requiring the expensive infrastructure investments and mostly implemented in the uninterrupted freeway network with limited spatial system expansion. This paper develops an advanced decentralized traveler information System (ATIS) using vehicle-to-vehicle (V2V) communication system whose performance (drivers' travel time savings) are enhanced by three complementary functions (autonomous automatic incident detection algorithm, reliable sample size function, and driver behavior model) and evaluates it in the typical $6{\times}6$ urban grid network with non-recurrent traffic state (traffic incident) with the varying key parameters (traffic flow, communication radio range, and penetration ratio), employing the off-the-shelf microscopic simulation model (VISSIM) under the ideal vehicle communication environment. Simulation outputs indicate that as the three key parameters are increased more participating vehicles are involved for traffic data propagation in the less communication groups at the faster data dissemination speed. Also, participating vehicles saved their travel time by dynamically updating the up-to-date traffic states and searching for the new route. Focusing on the travel time difference of (instant) re-routing vehicles, lower traffic flow cases saved more time than higher traffic flow ones. This is because a relatively small number of vehicles in 300vph case re-route during the most system-efficient time period (the early time of the traffic incident) but more vehicles in 514vph case re-route during less system-efficient time period, even after the incident is resolved. Also, normally re-routings on the network-entering links saved more travel time than any other places inside the network except the case where the direct effect of traffic incident triggers vehicle re-routings during the effective incident time period and the location and direction of the incident link determines the spatial distribution of re-routing vehicles.

A Study on 'Verfremdung' effects in visual advertisements with a special reference to the <017-I-Touch series, The Hand Transformed into a Web >, mobile network advertisement (동영상 광고에서 나타나는 '소격화' 효과에 관한 연구 - 광고 <017-I-Touch편 (손이 물갈퀴) >를 중심으로 -관어영시광고중소출현적‘맥생화’효과적연구(關於影視廣告中所出現的‘陌生化’效果的硏究))

  • Jin, Ri-Long;Ahn, Sang-Soo;Kim, Jong-Deok
    • Archives of design research
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    • v.18 no.2 s.60
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    • pp.37-46
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    • 2005
  • Today's advertisement is dominated by visual images, which deliver messages in the most efficient and engaging way. Vivid and live images, through multimedia, attract the viewer to consume the products being advertised. In this course, the effect of 'Verfremdung' or alienation is often detected. This terminology was at first used in a epic play of Bertolt Brecht to signify a specific effect to block the empathy of the audience by reminding them of their position as the audience separate from the play. 'Verfremdung' helps them to have a sense of objectivity and critical attitude toward the performance. Multimedia commercials nowadays exhibit such a quality together with 'viewer participation:' criticism on reality: and 'speed.' In an advertisement for Shinsegi Communications' mobile system titled <017-I-Touch series, the hand transformed into a web>, the copy, 'my blood type is 'i', ' is accompanied by six unrelated fictitious scenes in which the same ocean appears as a common denominator. Because there is no connection between the scenes, free imagination of the viewer has to be involved and thus plays a significant role in making them into a context. This fact dearly exhibit some characteristics of post- modern advertisement. Momentary 'Gap' and 'Difference' between scenes contribute to 'Verfremdung' or alienation' that makes it hard for the consumers to comprehend the content on the spot. Such an uneasy situation, however, keeps the viewers thinking about the advertisement itself. While repeatedly exposed to the alienated images, the viewers come to get involved in the advertisement, trying to make the fragmented images into a coherent context. In addition, the leaps between the scenes produce a sense of 'speed' in a context, which adds more impact to the way of delivering messages using multimedia. With the help of multimedia, 'Verfremdung: which was originally intended to bring about objective and critical altitude of the audience in a play, plays a crucial role in attracting the viewer's attention and conveying a specific message in a moment in contemporary advertisement.

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