• 제목/요약/키워드: Circulation change

검색결과 701건 처리시간 0.029초

일강우자료를 이용한 강우사상의 변동 특성 분석 (Characteristic Change Analysis of Rainfall Events using Daily Rainfall Data)

  • 오태석;문영일
    • 한국수자원학회논문집
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    • 제42권11호
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    • pp.933-951
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    • 2009
  • 지구온난화에 따른 기후변화가 우리나라의 물순환 과정에 영향을 미칠 수 있다. 강우는 여러 기상인자들과 복잡한 영향을 주고 받으며 발생한다. 따라서 강우는 물순환 과정에서 기후변화에 따른 영향을 크게 받는 인자 중의 하나이다. 본 연구에서는 강우특성을 나타낼 수 있는 여러 시계열 자료를 구축하였다. 또한 강우의 발생 시계열을 연별, 계절별 및 월별로 구성하여 분석하였다. 분석 방법은 시계열 자료의 평균과 표준편차의 변동성 분석과 경향성 분석을 수행하였다. 또한, 최근 10년 동안에 강우특성의 변화에 대한 상대오차를 계산하여 과거 자료들과 비교하였다. 분석 결과에서 강우자료의 고유 특성인 무작위성에 의하여 뚜렷한 통계적 결과는 나타나지 않았다. 그러나 일반적으로 최근 10년간 강우량은 증가하였으며, 강우일수는 감소하는 추세를 보였다. 또한, 계절별과 월별에 따른 강우특성의 변화가 다르게 나타나고 있음을 확인할 수 있다.

미세전류발생 신발 착용이 만성 족저근막염 환자의 혈류량 변화에 미치는 영향 (Effects of Induced Microcurrent Shoes on Change of Blood Circulation to patients with Chronic Plantar)

  • 이윤미;최상준;;조미숙;조정선;조용호;박소현;박래준
    • The Journal of Korean Physical Therapy
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    • 제18권3호
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    • pp.71-78
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    • 2006
  • Purpose: The purpose of this study was to investigate how induced microcurrent shoes influenced changes of the blood circulation in patients with Plantar Fasciitis. Methods: Initially, the subjects were comprised of 5 males and 5 females, who agreed with this research and are more than fifty years old, but 4 of those were dropped during the experiment. They all have plantar fasciitis and pain on their feet. Subjects wore the induced microcurrent shoes for more than 4 hours everyday during 4 weeks. When they wore those shoes, they also wore the specially produced shocks made of silver-mixed thread and they were asked to avoid intense exercise. Assessments were carried out before and after walking on a treadmill and we measured changes between the test before and after 4 weeks. In the examination of the before test, general shoes were used, and in the examination of the after test, induced microcurrent shoes were used. Temperature difference was measured by thermograpy DOREX spectrum 9000MB(USA). Subjects walked total 20 minutes and during gait, the walking rate on a treadmill was increased from 2Km/h to 3Km/h after 10 minutes. We measured plantar temperature by thermograpy especially both heel, 1st, and 5th metatarsal areas. Results: Firstly, in comparison of the blood circulation on the left and right foot at 0 week and 4 weeks, it tended toward increasing blood circulation but there was. no statistically significant difference (p>0.05). Secondly, in comparison of the blood circulation before and after treadmill with the induced microcurrent shoes, the blood circulation of the heel and the 5th area on the right foot was increased to all subjects(p<0.05). Conclusion: The results of this study revealed that subjects showed tendency to increase blood circulation in both right and left feet after wearing microcurrent shoes and specially after walking treadmill at 4 weeks. Therefore induced microcurrent shoes are useful to improve blood circulation for patients with plantar fasciitis.

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Modeling of Grade Change Operations in Paper Plants

  • 고준석;여영구;하성문;고두석;강홍
    • 한국펄프종이공학회:학술대회논문집
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    • 한국펄프종이공학회 2003년도 추계학술발표논문집
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    • pp.291-305
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    • 2003
  • In this work we developed the closed-loop model of a paper machine during grade change with the intention to provide a reliable dynamic model to be used in the model-based grade change control scheme. During the grade change, chemical and physical characteristics of paper process change with time. It is very difficult to represent these characteristics on-line by using physical process models. In this work, the wet circulation part and the drying section were considered as a single process and closed-loop identification technique was used to develop the grade change model. Comparison of the results of numerical simulations with plant operation data demonstrates the effectiveness of the model identified.

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지구온난화에 따른 홍수 및 가뭄 발생빈도의 변화와 관련하여 : 1. 연/월강수량의 변화에 따른 일강수량 분포의 변화분석 (On the Change of Flood and Drought Occurrence Frequency due to Global Warming : 1. Change of Daily Rainfall Depth Distribution due to Different Monthly/Yearly Rainfall Depth)

  • 윤용남;유천상;이재수;안재현
    • 한국수자원학회논문집
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    • 제32권6호
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    • pp.617-625
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    • 1999
  • 지구 온난화는 산업혁명이후 이미 시작되었으며 최근에 와서 그 정도가 심해지고 있다. CO2와 같은 온실기체의 증가를 가장 큰 원인으로 하는 지구 온난화의 영향이 아직 정량적으로 밝혀지고 있지만 대기순환모형(General Circulation Model: GCM)을 이용한 연구에서 이러한 온실기체의 증가가 지구의 평균온도를 상승시킨다고 밝히고 있다. 지구 온난화는 전지구적 물의 순환에도 영향을 미쳐 지구 곳곳의 강수패턴에 변화를 가져오는데 근래에 자주 발생하는 대규모 가뭄이나 홍수화 같은 극치기상이 이러한 지구온난화의 간접증거로 자주 언급되곤 한다. 국내의 경우도 예외는 아니어서 근래에 들어 빈번한 홍수 및 가뭄을 경험하고 있다. 본 연구에서는 지구온난화에 따른 홍수 및 가뭄의 빈도변화 분석을 목적으로 한다. 이러한 연구목적을 달성하기 위해 먼저 현재상태가 지구온난화 과정의 한 시점이라는 가정 아래 현재까지 관측된 일강수량 자료를 분석하여 과거 연강수량의 증가가 일강수량의 분포에 어떤 식으로 영향을 미치고 있는지를 분석하여 보았다. 대상자료는 금강유역의 17개 지점을 선정하여 이용하였고, 분석결과로서 연강수량과 무강수일수는 상대적으로 작은 상관을 보이고 있음을 밝힐 수 있었으며 오히려 10mm이하 또는 50mm이상의 강수일수에 0.8-0.9의 높은 상관을 보임을 파악할 수 있었다.

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A Study of Transient Estuarine Circulation in the Chunsu Bay, Yellow Sea: Impact of Freshwater Discharge by Artificial Dikes

  • Jeong, Kwang-Young;Ro, Young Jae;Kang, Tae Soon;Choi, Yang Ho;Kim, Changsin;Kim, Baek Jin
    • 해양환경안전학회지
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    • 제26권3호
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    • pp.242-253
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    • 2020
  • This study examined the ef ects of freshwater discharge by artificial dikes from the Kanwol and Bunam lakes on the dynamics in the Chunsu Bay, Yellow Sea, Korea, during the summer season based on three-dimensional numerical modeling experiments. Model performances were evaluated in terms of skill scores for tidal elevation, velocity, temperature, and salinity and these scores mostly exceeded 90 %. The variability in residual currents before and after the freshwater discharge was examined. The large amount of lake water discharge through artificial dikes may result in a dramatically changed density field in the Chunsu Bay, leading to an estuarine circulation system. The density-driven current formed as a result of the freshwater inflow through the artificial dikes (Kanwol/Bunam) caused a partial change in the tidal circulation and a change in the scale and location of paired residual eddies. The stratification formed by strengthened static stability following the freshwater discharge led to a dramatic increase in the Richardson number and lasted for a few weeks. The strong stratification suppressed the vertical flux and inhibited surface aerated water mixing with bottom water. This phenomenon would have direct and indirect impacts on the marine environment such as hypoxia/anoxia formation at the bottom.

Hemodynamic Characteristics Affecting Restenosis after Percutaneous Transluminal Coronary Angioplasty with Stenting in the Angulated Coronary Stenosis

  • Lee, Byoung-Kwon;Kwon, Hyuck-Moon;Roh, Hyung-Woon;Cho, Min-Tae;Suh, Sang-Ho
    • International Journal of Vascular Biomedical Engineering
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    • 제1권1호
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    • pp.13-23
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    • 2003
  • Backgrounds: The present study in angulated coronary stenosis was to evaluate the influence of velocity and wall shear stress (WSS) on coronary atherosclerosis, the changes of hemodynamic indices following coronary stenting, as well as their effect of evolving in-stent restenosis using human in vivo hemodynamic parameters and computed simulation quantitatively and qualitatively. Methods: Initial and follow-up coronary angiographies in the patients with angulated coronary stenosis were performed (n=80). Optimal coronary stenting in angulated coronary stenosis had two models: < 50 % angle changed(model 1, n=43), > 50% angle changed group (model 2, n=37) according to percent change of vascular angle between pre- and post-intracoronary stenting. Flow-velocity wave obtained from in vivo intracoronary Doppler study data was used for in vitro numerical simulation. Spatial and temporal patterns of velocity vector and recirculation area were drawn throughout the selected segment of coronary models. WSS of pre/post-intracoronary stenting were calculated from three-dimensional computer simulation. Results: Follow-up coronary angiogram demonstrated significant difference in the percent of diameter stenosis between two groups (group 1: $40.3{\pm}30.2$ vs. group 2: $25.5{\pm}22.5%$, p<0.05). Negative WSS area on 3D simulation, which is consistent with re-circulation area of velocity vector, was noted on the inner wall of post-stenotic area before stenting. The negative WSS was disappeared after stenting. High spatial and temporal WSS before stenting fell into within physiologic WSS after stenting. This finding was prominent in Model 2 (p<0.01) Conclusions: The present study suggests that hemodynamic forces exerted by pulsatile coronary circulation termed as WSS might affect on the evolution of atherosclerosis within the angulated vascular curvature. Moreover, geometric change, such as angular difference between pre / post-intracoronary stenting might give proper information of optimal hemodynamic charateristics for vascular repair after stenting.

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A Change of Large-scale Circulations in the Indian Ocean and Asia Since 1976/77 and Its Impact on the Rising Surface Temperature in Siberia

  • Lim, Han-Cheol;Jhun, Jong-Ghap;Kwon, Won-Tae;Moon, Byung-Kwon
    • 한국지구과학회지
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    • 제30권5호
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    • pp.660-670
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    • 2009
  • This study examines the changes of an interdecadal circulation over the Asian continent to find cause of the surface warming in Siberia from 1958 to 2004. According to our study, there is a coherency between a long-term change of sea surface temperature in the Indian Ocean and the rapid increase of air temperature in Siberia since 1976/1977. In this study, we suggest that mean wind field changes induced by the positive sea surface temperature anomalies of the Indian Ocean since 1976/1977 are caused of inter-decadal variations in a large-scale circulation over the Asian continent. It also indicates that the inter-decadal circulation over the Asian continent is accompanied with warm southerly winds near surface, which have significantly contributed to the increase of surface temperature in Siberia. These southerly winds have been one of the most dominant interdecadal variations over the Asian continent since 1976/1977. In addition, we investigated the long-term trend mode of 850 hPa geopotential height data over the Asian continent from the Empirical Orthogonal Function (EOF) analysis for 1958-2004. In result, we found that there was an anomalously high pressure pattern over the Asian continent, it is called 'the Asian High mode'. It is thus suggested that the Asian High mode is another response of interdecadal changes of large-scale circulations over the Asian continent.

의과대학의 기능과 동선에 관한 건축계획 연구 (A Study on the Architectural Planning of the Function and Circulation in the College of Medicine)

  • 최광석;권순정
    • 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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    • 제27권2호
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    • pp.15-24
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    • 2021
  • Purpose: This study is to present basic data on the Architectural planning of the college of medicine by arranging the functional zoning planning, functional unit planning, and circulation planning, based on the diversification of medical education and the changes of Learning spaces. Methods: This study was conducted by literature review on existing medical education method and learning space planning. And then on-site surveys and questionnaire were conducted on existing facilities. Results: The diversification of medical education has already been progressing for a long time, and the development of information technology is integrated into the learning space, and the evolution of the learning method and the flexibility of the learning space give effect to the change of the learning space. ① This study reconstructed the existing classification method of university facilities into the fuctional zoning method that combines the architectural concept of function and movement. ② The functions and functional units of the college of medicine according to the proposed functional zone were arranged, and the space required for the medical college was suggested. ③ The function and type of movement of medical college can be classified into professor/student fusion type, teaching and research separation type, and learning and learning shared space integrated arrangement type. In the future, it is necessary to consider fusion type or integrated arrangement type rather than separation type. Implications: the evolution of the learning method and the flexibility of the learning space give effect to the change of the learning space.

기후변화와 토지피복변화를 고려한 한강 유역의 수자원 영향 평가 (Impact Assessment of Climate Change and Land use change on Water Resources in Han River)

  • 김병식;김보경;권현한;윤석영
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2009년도 학술발표회 초록집
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    • pp.929-933
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    • 2009
  • 전 세계적으로 기후변화와 이상기후에 대한 관심이 높아지고 있다. IPCC(2001)는 "기후변화"라는 요소가 기온 증가, 강우강도 및 빈도 변화와 이들로 인한 증발산의 변화, 유출량의 시 공간적 변동을 초래하여 수자원의 효율적 관리 및 안정적인 공급에 어려움을 증대시킬 것으로 전망하였다. 이에 따라 세계 각국은 미래 기후에 대한 보다 정확한 정보를 얻기 위하여 IPCC 권장 시나리오인 SRES(Special Report in Emission Scenario)기반의 GCM(General Circulation Model)과 RCM(Regional Circulation Model)을 이용하고 있으며 특히, 최근에는 고해상도 자료를 생산함으로써 국부지역에 대한 지형학적 특성을 효과적으로 모의할 수 있는 RCM 모형을 이용한 연구가 국외를 중심으로 진행되고 있다(권현한 등, 2008). 본 연구에서는 미래 한강 유역의 수자원 변동성을 평가하기 위하여 CA-Markov Chain 기법으로부터 토지이용변화를, 기온과 강수자료을 독립변수로 이용한 다중 회귀식으로부터 미래 NDVI를 추정하고 기상청에서 제공하는 RegCM3-지역지후모형으로부터 축소기법을 이용하여 추정된 KMA RCM 50set 기후변화시나리오를 SLURP 모형에 입력하였다. 2001년부터 2090년까지 총 90년에 대한 한강 유역의 미래 유출모의를 실시한 후 각 댐별 과거와 미래 유출량을 월별로 비교하고 이들의 유황분석을 실시하였다.

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