• 제목/요약/키워드: Stream flow

검색결과 2,014건 처리시간 0.034초

동작 인식을 위한 교사-학생 구조 기반 CNN (Teacher-Student Architecture Based CNN for Action Recognition)

  • ;이효종
    • 정보처리학회논문지:컴퓨터 및 통신 시스템
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    • 제11권3호
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    • pp.99-104
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    • 2022
  • 대부분 첨단 동작 인식 컨볼루션 네트워크는 RGB 스트림과 광학 흐름 스트림, 양 스트림 아키텍처를 기반으로 하고 있다. RGB 프레임 스트림은 모양 특성을 나타내고 광학 흐름 스트림은 동작 특성을 해석한다. 그러나 광학 흐름은 계산 비용이 매우 높기 때문에 동작 인식 시간에 지연을 초래한다. 이에 양 스트림 네트워크와 교사-학생 아키텍처에서 영감을 받아 행동 인식을 위한 새로운 네트워크 디자인을 개발하였다. 제안 신경망은 두 개의 하위 네트워크로 구성되어있다. 즉, 교사 역할을 하는 광학 흐름 하위 네트워크와 학생 역할을 하는 RGB 프레임 하위 네트워크를 연결하였다. 훈련 단계에서 광학 흐름의 특징을 추출하고 교사 서브 네트워크를 훈련시킨 다음 그 특징을 학생 서브 네트워크를 훈련시키기 위한 기준선으로 지정하여 학생 서브 네트워크에 전송한다. 테스트 단계에서는 광학 흐름을 계산하지 않고 대기 시간이 줄어들도록 학생 네트워크만 사용한다. 제안 네트워크는 실험을 통하여 정확도 면에서 일반 이중 스트림 아키텍처에 비해 높은 정확도를 보여주는 것을 확인하였다.

금강수계의 하천형태학적 특성인자에 의한 갈수량 산정 (Low flow Calculation by Stream Morphological Characteristic Parameters in Geum River System)

  • 안상진;윤용남;강관원
    • 물과 미래
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    • 제14권1호
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    • pp.31-37
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    • 1981
  • 금강수계의 미계획지점에 대한 갈수량빈도곡선의 합성은 하천형태학적 인자인 유역면적, 유역의 기복량, 하천의 연장 및 미국연방주환경국의 하천수질기준인 10년 7월 평균 갈수량을 이용한 상관관계를 분석함으로서 가능하였다.

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조류자원의 평가에 관한 연구 (A Study on Assessment of Tidal Stream Resources)

  • 양창조;최민선;이영호
    • 한국마린엔지니어링학회:학술대회논문집
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    • 한국마린엔지니어링학회 2011년도 전기공동학술대회 논문집
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    • pp.309-309
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    • 2011
  • This paper outlines extraction potential of tidal stream resources from the simplified channel in which flow is driven by a head difference between inlet and outlet. Energy extraction alters the flow within a simple channel, and extraction of 10% energy flux in a natural channel would give rise to a flow speed reduction of about 5.7%.

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북한산국립공원에서 동결융해침식토사 및 유량이 계류수질에 미치는 영향 분석 (Analysis of Influences of the Solifluction Soil and Stream flow on the Stream Water Quality of Bukhansan National Park)

  • 박재현
    • 한국환경복원기술학회지
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    • 제6권2호
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    • pp.11-20
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    • 2003
  • This research was conducted to investigate the influences of the solifluction soil and amount of flow on the stream water quality of the Bukhansan National Park from March to october, 2002. The average pH of stream water was higher than that caused by solifluction soil. The average electrical conductivity of upstream water was about 2.1~2.8 times lower than that of downstream water. Linear regression analysis showed that pH and amount of anion($Cl^-$, ${NO_3}^-$, ${SO_4}^{2-}$) of stream water were very significantly correlated with those at the caused by solifluction soil. Structures for erosion control along both sides of stream channel should be designed in order not to influence upon solifluction soil and stream water quality.

비선형 Boussinesq방정식을 이용한 유로대수층 해석 (Analysis of stream-aquifer using nonlinear Boussinesq equation)

  • 정재성;김민환;방경미
    • 한국환경과학회지
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    • 제11권1호
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    • pp.57-61
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    • 2002
  • To investigate the flow characteristics by the water stage variation between stream-aquifer, the new solution of nonlinear Boussinesq equation was derived and extended using the Boltzmann transformation. The soundness of the analytic solution obtained from this study was examined by the comparison with the linearized analytic solution and the numerical solution by finite difference method. And the movement, velocity, flowrate and volume of flow caused by the stage variation of stream and the existence of regional gradient were estimated. This new analytic solution can express the groundwater movement between stream-aquifer. So, it might be helpful to manage water environment.

Second Law Optimization of Water-to-Water Heat Pump System

  • Kim, Kyu-Hyung;Woo, Joung-Son;Lee, Se-Kyoun
    • Journal of Mechanical Science and Technology
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    • 제17권1호
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    • pp.122-128
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    • 2003
  • This paper presents a thermodynamic analysis of heat pump system using water as a heat source and heat sink. The primary object in this study is the optimization of exergetic efficiency. Two different systems, 2-stream and 1-stream system, are analyzed in detail. Mass flow ratio (the ratio of mass flow rate of water through evaporator to that through condenser) is identified as the most important parameter to be optimized. It is shown that there exists an optimum mass flow ratio to maximize exergetic efficiency. The variation of optimum exergetic efficiency of 2-stream system is quite small and the value lies between 0.2∼0.23 for the range of investigation in this study. However, far better performance can be obtained from 1-stream system. This means considerable irreversibilities are generated through condenser of the 2-stream system. The effects of adiabatic efficiency of compressor-motor unit on the overall system performance are also examined in the analysis.

자연형 소하천 정비에 따른 하상변동 특성 (Riverbed Change Special Quality by Nature Style Small Stream Improvement)

  • 정해원;정재훈;윤정환;박승기
    • 한국농공학회:학술대회논문집
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    • 한국농공학회 2005년도 학술발표논문집
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    • pp.330-335
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    • 2005
  • This study was performed for the analysis of the variation characteristics on riverbed according to the arrangement of stream. It was monitored of the variation progress of riverbed dependent on the elapsed time after the arrangement and It was studied that the hydraulic adjustment of the riverbed caused by the variation of the riverbed. The large amount of deposit just after the construction in which the riverbed was arranged to natural form was come from the reduction of flow rate by the installed artificialities such as weirs and stone weirs and by the stones or the concrete blocks attached to the stream sides of riverbanks. This phenomenon was well consistent with the usual characteristics that the accumulation is induced on upper stream of hydraulic artificialities and the erosion is induced on down stream of hydraulic artificialities. The large reduction of the deposit 1 year later after the construction showed that the riverbed eroded considerably because of the recovery of flow amount and the rise of flow rate.

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수치모형을 이용한 도시 하천의 홍수특성 분석 (Analysis of Flood Characteristics in Urban Stream Basin Using Numerical Models)

  • 윤선권;문영일;김종석;최병화
    • 한국방재학회:학술대회논문집
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    • 한국방재학회 2007년도 정기총회 및 학술발표대회
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    • pp.599-602
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    • 2007
  • Flood damage has been increased due to abnormal climate and extreme rainfall. Especially, the increase of impervious areas and the decrease of flow travel times due to the urbanization have been caused heavy division of flood with the recent rainfall characteristics. In this study, hydrodynamics flow analysis has been needed two dimensional numerical analysis for correct stream flow interpretations on bridges as hydraulic structures in rivers. Therefore, comparative analysis has been accomplished by using HEC-RAS model and SMS-RMA2 model for one and two dimensional flow. Also, flood characteristics have been analyzed in urban stream basin.

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보청천 유역의 수리학적 특성분석 (Hydraulic Characteristics of Bocheong Stream Basin)

  • 전민우;연규방;조용수;김종훈
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2009년도 학술발표회 초록집
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    • pp.1311-1315
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    • 2009
  • Understanding of the hydraulics of flow is very important to support the management of river. The cross-sectional area, average velocity, flow depth and discharge can be regarded as a power function each other. In this paper the flow of Bocheong stream basin is experimentally studied. The correlation analysis was performed between observed hydraulic factors by the power type function. The constants resulted from the correlation analysis were calculated by the geomorphologic characteristics of the watershed using the power type function. The correlation coefficients between the hydraulic factors were appeared close to unit having strong correlationship. The two conditions of equality of the continuity equation were analysed, and the conditions were found to be good results. From these results the observed hydraulic data of Bocheong stream basin can be concluded as a reliable data. The correlation coefficients between the parameters of the hydraulic characteristics and geomorphologic factors were found to be close to unit.

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사각형 둔각물체 주위의 유동장 특성에 관한 수치적 연구 (Numerical Study on the Isothermal Flow Field abound Rectangular Cross Section Bluff Body)

  • 이정란;이의주
    • 한국안전학회지
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    • 제27권5호
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    • pp.35-41
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    • 2012
  • The Numerical simulation was performed on the flow field around the two-dimensional rectangular bluff body in order to complement the previous experimental results of the bluff body stabilized flames [1]. For both fuel ejection configurations against an oxidizer stream, the flame stability was affected mainly by vortex structure and mixing field near bluff body. FDS(Fire Dynamic Simulator) based on the LES(Large Eddy Simulation) was employed to clarify the isothermal mixing characteristic and wake flow pattern around bluff body. The air used atmosphere and the fuel used methane. The result of counter flow configuration shows that the flow field depends on air velocity but the mixing field is influenced on the fuel velocity. At low fuel velocity the fuel mole fraction is below the flammable limit and hence the mixing is insufficient to react. Therefore, as the result, the flame formed at low fuel velocity is characterized by non-premixed flames. For the flow field of co-flow configuration, flame stability was affected by fuel velocity as well as air velocity. the vortex generated by fuel stream has counter rotating direction against the air stream. Therefore, the momentum ratio between air and fuel stream was important to decide the flame blow out limit, which is result in the characteristic of the partially premixed reacting wake near extinction.