• Title/Summary/Keyword: stream direction

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Impact of Organizational Learning Culture on Job Satisfaction and Organizational Commitment: A Structural Equation Modeling Approach

  • LIM, Taejo
    • Educational Technology International
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    • v.6 no.2
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    • pp.43-58
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    • 2005
  • The purpose of this study was to investigate the impact of organizational learning culture on job satisfaction and organizational commitment. Two streams of scholarly work have provided the theoretical foundations for this study. The first stream comes from the literature on learning organization. The second stream of the theoretical foundation comes from an extensive literature on attitude-intention-behavior relationships. In addition, this study was tested three alternative models. Alternative model 1 employed job satisfaction as the mediating commitments variable between learning culture and organizational commitment. Alternative model 2 used organizational commitment as the mediating variable between learning culture and job satisfaction. Finally, alternative model 3 specified a direct impact of learning culture on both job satisfaction and organizational commitment, and reciprocal linkages between these two variables. The results of this study support the hypothesized relations among an organization's learning culture, job satisfaction, and organizational commitment. The findings of this study are various congruent with a widely accepted hypothesis that job satisfaction serves as an appraisal function in evaluating various work environments and determining emotional responses such as organizational commitment. Organizational learning culture is one of the important factors that organizations cannot overlook. Therefore, the findings of this study provide a new direction for researchers seeking to explain the complex relations among these central organizational variables.

An Experimental Study of Film Cooling Characteristics at Supersonic Free Stream Conditions (초음속 주유동 환경에서의 막냉각 특성 시험 연구)

  • Kim, Manshik;Lee, Dong Min
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.4
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    • pp.342-348
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    • 2017
  • In this paper, film cooling characteristics at supersonic free stream conditions were examined experimentally by applying an IR-thermography. Film cooling experiments were carried out in a free-jet facility at Mach number of 3.0 and with unit Reynolds number of $42.53{\times}10^6$ and $69.35{\times}10^6$ using wedge shaped film cooling model which has a converging film cooling nozzle. Film cooling efficiency was calculated by measuring the surface temperature of PEEK(Polyether Ether Ketone) and the effects of angle of attack and blowing ratios on the film cooling efficiency were examined. The measured wall temperature was significantly reduced by the film cooling flow compared with the results without the film cooling flow. The usefulness of film cooling was also confirmed by the surface heat flux calculated using the surface temperature history of PEEK. As the blowing ratio increases the protected area of PEEK was also expanded along the direction of free stream and film cooling flow.

Tailings Behavior and Performance of the Tailings Return Unit of the Head-feed Combine(II) -Theoretical and Experimental Analysis of Tailing Behavior- (자탈형(自脫型) 콤바인 환원장치(還元裝置)의 환원물(還元物) 유동현상(流動現象)과 환원성능(還元性能) 개선(改善)에 관한 연구(硏究)(II) -환원물(還元物) 유동(流動)의 이론해석(理論解析)과 실험분석(實驗分析)-)

  • Cho, Y.K.;Chung, C.J.;Choi, K.H.;Park, P.K.
    • Journal of Biosystems Engineering
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    • v.16 no.2
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    • pp.133-141
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    • 1991
  • This study was undertaken to investigate the structural and configurational characteristics of the tailings return-unit in the commercially available head-feed combines and to study the aero-dynamical behavior of the tailings in the units. The mathematical model of the motion of tailings in the thrower casing was developed and the simulated trajectories for different type of units was analyzed to compare with the measured ones. The air-stream velocity profile in various locations along the tailings returning duct was measured to find the effect of configurational characteristics and blade tip speed. The results of the study are summerized as follows. 1. The ejecting angle, which is the angle between the direction of the particle velocity ejecting from the blade and the horizontal axis, was found to be about $66^{\circ}$ in both the simulation and experiment. The angle was much greater than the setting angle of actual duct of the combines studied, which were $48{\sim}56^{\circ}$. By comparison of these results, it was suggested to change duct setting angle so as to reduce the frictional force, between the duct wall and tailings, by reducing the difference between the ejecting and setting angles. 2. The velocity of the air stream in the duct was in general higher in the upper bound of the duct compared to the lower and decreased as the stream went toward the end of duct. The comparison of the tailings units among the combines studied showed a superior performance with the tapered duct having small diameter in the outlet and with greater number of thrower blade.

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A Case Study of Post-Implementation Evaluation for Close-to-Nature Stream Improvement Work (자연형 하천정화사업의 시행 후 평가에 관한 사례연구)

  • Lee, Hee-Won;Kim, Do-Sik;Lee, Seok-Hwan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.3
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    • pp.1405-1411
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    • 2012
  • This study deals with the case of "Close-to-Nature Improvement Work of Cheonancheon and Wonseongcheon in Cheonan", which has been completed at the end of 2009. The purpose of this study is to evaluate the result of this work and suggest a future direction of development and supplementation of this project. In the course of his study, theoretical researches about urban stream and restoration precedents, observational survey and user questionnaire and comparative analysis have been conducted. According to the study, the most prominent problems of Cheonancheon in comparison with Wonsungcheon are water pollution, low use and participation of residents. As location based future development concept, Cheonancheon as various event space for visitors, Wonsungcheon as recreational space for residents are suggested.

Analysis of Stream Physiographic Characteristics of River Basin by using GIS (지리정보시스템을 이용한 하천유역의 지상학적 특성분석)

  • Ahn, Seung-Seop;Jo, Myung-Hee
    • Journal of the Korean Association of Geographic Information Studies
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    • v.2 no.3
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    • pp.23-34
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    • 1999
  • This study proposed the possibility of GIS to analyze stream physiographic characteristics of river basin which is important control factor in complex water management. Based on five 1:25,000 topographic maps which cover Yengchon Dam area locates upper area of Kumho River, this study analyzed the characteristics using Arc/Info(UNIX) GIS. Comparing its results and those from the existing method using digital planimeter, it could conclude as follows; First, as the results of the analysis of hypsometric curve of Yeungchon Dam area, it has the topographic characteristics of youth and maturity. And the landform of Yengchon Dam area has developed with regularity when Horton's three laws on the morphology of stream is applied. Second, the possibility of applying GIS to data management and utilization is sufficient even if it requires long time to construct topographic attribute data. Finally, a further research is needed on watershed direction with landform for the purpose of analyzing water source management and topographic property effectively.

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Estimation of Soil Erosion and Sediment Yield in Mountainous Stream (산지형 하천의 토양침식 및 토사유출량 산정)

  • Ko, Jae-Wook;Yang, Sung-Kee;Yang, Won-Seok;Jung, Woo-Yeol;Park, Cheol-Su
    • Journal of Environmental Science International
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    • v.22 no.5
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    • pp.599-608
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    • 2013
  • Jeju island, which is located along the moving path of typhoon, suffers from flooding and overflow by torrential rain. So abrupt runoff occurring, damages of downstream farm field and shore culturing farms are increasing. In this study, Oaedo stream, one of the mountainous streams on Jeju island, was selected as the basin of study subject and was classified into 3 sub-basins, and after the characteristics of subject basin, the soil erosion amount and the sediment delivery of the stream by land usage distribution were estimated with the use of SATEEC ArcView GIS, the sediment yield amount of 2000 and 2005 was analyzed comparatively. As a result of estimating the sediment yield amount of 2000, the three sub-basins were respectively 12,572.7, 14,080 and 157,761 tons/year. and sediment yield amounts were estimated as 35,172.9, 5,266 and 258,535 tons/year respectively in 2005. The soil erosion and sediment yield amount of 2005 using single storm rainfall were estimated high compared with 2000, but for sub-basin 2, the values rather decreased due to changes in land use, and the land coverage of 2005, since there are many classifications of land usage compared with 2000, enabling to reflect more accurate land usage condition, could deduce appropriate results. It is anticipated that such study results can be utilized as basic data to propose a direction to predict the amount of sediment yield that causes secondary flooding damage and deteriorates water quality within detention pond and grit chamber, and take action against damages in the downstream farm field and shore culturing farms.

Analysis of Analytical Models and Numerical Model for Evaluating Induced Infiltration Rate (유도침투량의 정량화를 위한 해석모형과 수치모형의 분석)

  • Lee, Do-Hun;Lee, Eun-Tae
    • Journal of Korea Water Resources Association
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    • v.32 no.3
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    • pp.301-310
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    • 1999
  • In this paper a numerical model and two analytical models in the hydraulically connected stream-aquifer system were analyzed to compare the induced infiltration rate curves derived from each model. And we also examined the effects of anisotropy of hydraulic conductivity and the direction of the ambient ground water flow on the quantification of the induced infiltration rate. The induced infiltration rate curve determined by models is very simple and useful for estimating the induced infiltration rate since it contains only four physical variables such as the induced infiltration rate, the pumping rate, the distance between the pumping well and the stream, and the ambient ground water flow rate. Under the conditions tested in this paper the induced infiltration rate curves resulted from the Wilson's analytical model and FEWA numerical model were in good agreement, and the anisotropic ratio of hydraulic conductivity was evaluated as a physical factor which influences the behaviour of the induced infiltration rate curve. The methods and results of the paper might Icad to improve the understanding of the induced infiltration phenomenon and can be applied to the planning and disign of pumping well and the optimal determination of the induced infiltration rate and pumping rate for water quality management of the water supply wells.

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A Study on the Landscape Arrangement Simulation System for Small Streams (소하천 경관정비 모의시스템에 관한 연구)

  • 김선주;윤경섭;이광야;박성삼
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.39 no.5
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    • pp.86-96
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    • 1997
  • The arrangement of small streams in rural area, in the past times, attached importance to the prevention of flood damage through the straightening and lining of streams. Recently, the way of small stream arrangement is introducing the idea of water friendly environment or friendly space. As a result, there has been much concern with water favorable river management model which may lead to control flood. However, it is very difficult to develop a model applicable to all types of rivers, since each river has different flow velocity, flow amount and unique ecological characteristics. In this study, photo processing technique, one of landscape simulation methods, has been adopted because it helps to visually express and comprehensively evaluate pre and post scenery and easily applicable. Some important guideline and technique for the planning of small stream landscape arrangement are mentioned in this study. The simulation system for acquiring water favorable space and arranging landscapes needs to develop database which can forecast various types of landscape. It may also be used for the bases of planning and designing river environment arrangement. Computer aided image processing system enables to make selective planning in river environment arrangement. It may also enables to develop the methods for river environment development, ecology conservation, and multipurpose space utilization. Moreover, it makes economic river arrangement by applying river environment arrangement methods relevant to geographical characteristics. There are some limitations in this study, such as shortage of exact investigation on the stream direction and velocity in landscape arrangement. Continuous monitoring and research may be required to develop techniques through the application of computer graphics and digital image processing.

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Analysis of Flood Inundation Using LiDAR and LISFLOOD Model (LiDAR 고도자료와 LISFLOOD 모형을 이용한 홍수범람해석)

  • Choi, Cheon-Kyu;Choi, Yun-Seok;Kim, Kyung-Tak
    • Journal of the Korean Association of Geographic Information Studies
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    • v.16 no.4
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    • pp.1-15
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    • 2013
  • Great loss of life and property has been occurred by the severe flood globally. In Korea, a flood inundation map is used as one of the non-structural measures for reducing flood damage, and various inundation models have been studied for flood inundation analysis. This study applies LiDAR data and LISFLOOD model for flood inundation analysis and discusses the the modeling results from levee breaching scenarios for evaluating the applicability of the model to stream inundation modeling. In the results of LISFLOOD modeling, maximum inundation area was similar to the inundation map by HEC-RAS model just less than 4%. The inundation area by each levee breaching scenario showed the difference from 0.2% to 6.5%. Inundation processes were different each other according to the position of levee breach point, and maximum inundation area and depth were changed by the flow direction of stream and flood plain. This study shows that LISFLOOD model can be applied properly to stream inundation analysis using various inundation scenarios.

Topographical Analysis of the Potholes in Jakgwaecheon Stream in Ulsan (울산 작괘천의 포트홀에 관한 지형분석)

  • Kim, Tae-hyeong;Kong, Dal-yong;Lim, Jong-deock;Jung, Seung-ho;Yu, Yeong-wan
    • Korean Journal of Heritage: History & Science
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    • v.46 no.3
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    • pp.68-77
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    • 2013
  • This report is based on the investigation of potholes which are formed by fluvial erosion. A pothole is called so because it is a hole that looks like a coffeepot. The results of previous studies are applied to the 'Jakgwaecheon Porthole' of this study. The study is focused on the dimension and morphology of the Pothole and investigates the effects of stream sediments, river flow, geological structural lines, etc. on the formation of potholes. As a result of measuring 61 potholes in this area, we recognized that the elliptical dish-shaped cross sections are dominant and inferred that their longitudinal direction on the plain is affected by the direction of the stream flow. Also, 'Jakgwaecheon Pothole' is very characterized in terms of scale and morphology. Furthermore, it is harmonious with the beautiful landscape, humanity, and historical values and it can be suggested that it is qualified to be registered as a geoheritage structure.