• Title/Summary/Keyword: Inflows

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Water Quality Modeling by the WASP4 Model (WASP4 모형에 의한 수질모델링)

  • 조홍연;전경수;이길성
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.5 no.3
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    • pp.221-231
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    • 1993
  • WASP4. an estuarine or lake water quality model, wat applied to simulate future water qualities at alternative withdrawal sites for capital areas. Simulated water quality constituents were Chlorophyll a, nitrogen cycles, Phosphorus, BOD End DO. A Water budget analysis Using the monthly records of reservoir inflows and outflows between 1986 and 1990 was made to determine seasonally-averaged flowrates at model boundaries. Estimated flowrates were used. together with the seasonal water quality inputs simulated by the QUAL2E model, for the simulation of future water qualities. Sensitivities to the future pollutant inputs and possible future withdrawal alternatives were also analyzed. From simulations or future water qualities it is found that among the candidate withdrawal sites. the one located at the downstream end of the North Han River has the best future water quality in all quality constituents and the one at the downstream end of the South Han River has the worst Possible future withdrawal from the North Han River brings a slight increase or pollutant concentrations at existing withdrawal sites. but the aggravation of water quality is not significant.

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Characteristics of Seasonal Sediment Transport in Haeundae Beach (표층퇴적물 및 표사수지에 의한 해운대 해수욕장의 계절별 표사 이동특성)

  • Lee, Jong-Sup;Tac, Dae-Ho;Yoon, Eun-Chan;Kim, Seok-Yun
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.19 no.6
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    • pp.547-556
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    • 2007
  • The sediment transport by waves, wave-induced current and tidal current was calculated using the TRANSPOR2004, then the seasonal sediment budget was analyzed. Also, annual sediment budget was calculated, and sediment circulation patterns was deduced in the broad area including Haeundae beach. A sediment mainly inflows from the east coast of the beach and then moves to the eastward to the Dongback Is, where the 80% of inflow sediment transported to the eastward as a longshore sediment while 20% of them going out to the offshore at the center of the beach. Above results shows a good agreement with the sediment transport trend analysis results by the Gao model.

Incorporating Climate Change Scenarios into Water Resources Management (기후 변화를 고려한 수자원 관리 기법)

  • Kim, Yeong-O
    • Journal of Korea Water Resources Association
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    • v.31 no.4
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    • pp.407-413
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    • 1998
  • This study reviewed the recent studies for the climate change impact on water resource systems and applied one of the techniques to a real reservoir system - the Skagit hydropower system in U.S.A. The technique assumed that the climate change results in ±5% change in monthly average and/or standard deviation of the observed inflows for the Skagit system. For each case of the altered average and standard deviation, an optimal operating policy was derived using s SDP(Stochastic Dynamic Programming) model and compared with the operating policy for the non-climate change case. The results showed that the oparating policy of the Skagit system is more sensitive to the change in the streamflow average than that in the streamflow standard deviation. The derived operating policies were also simulated using the synthetic streamflow scenarios and their average annual gains were compared as a performance index. To choose the best operating policy among the derived policies, a Bayesian decision strategy was also presented with an example. Keywords : climate change, reservoir operating policy, stochastic dynamic programming, Bayesian decision theory.

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Study of Surges in a Large-Diameter Subteranean Diversion Channel with Multiple Surge Tanks (대심도 지하관로 배수 시스템의 서어징 현상에 관한 연구)

  • Jeong, Gwang-Geun;Yeo, Un-Sik;An, Tae-Jin
    • Journal of Korea Water Resources Association
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    • v.31 no.6
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    • pp.757-768
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    • 1998
  • rate of outflow is equated to the total rate of flow, both the state equation and its linearized equation yield almost identical oscillations of water levels. This shows that effects of pipe resistance on the surges are small, and justifies a free oscillation analysis. Free oscillation equation has six eigen modes of different periods, including a rigid mode which is existed when the pumped rate of outflow differs from the total rate of inflow. The six modes constitute a variety of surges dependent on different inflow and outflow conditions. Presence of the rigid mode needs sophisticated pump operations adjusted to real flood inflows.

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Analysis about relation of Won/Dollar Foreign Exchange Rate and Interest Rate of Korea (한국 원/달러환율과 금리의 관계분석)

  • 김종권
    • Proceedings of the Safety Management and Science Conference
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    • 2002.11a
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    • pp.305-319
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    • 2002
  • International capital movement has made progress at global liberalization of finance and foreign exchange, international monetary norm changing into floating exchange rate system, easiness of collection of information and trade at improvement of information communication technology from early of 1970's. Results of empirical test for relation between foreign exchange rate or various determination factors of foreign exchange rate and interest rate are followed by next sentences. First, according to relation between foreign exchange rate and interest rate, correlation for each of variables after OECD entrance is increased. But, long-term &short-term interest rate is affected by Hanbo & Kia's bankruptcy, continuous large scale coporates bankruptcy and crisis of foreign exchange. Therefore, financial instability is occured. If portfolio investment fund has been inflow as it is mollified by continuous shortage of foreign exchange and fall of country's credit rating, it is expected to have positive effect for long-term & short-term interest rate from appreciation of won against dollar. Second, results from relation between determination factor of foreign exchange rate and interest rate are followed by next sentences. If surplus of current account and goods account is continued, yield of corporate bond is to be stable. But, margin of surplus is expected to diminish after second quarter 98, and difference between external and domestic interest (after adjusting foreign exchange rate) is to be diminished. And if net inflows of foreign investor's fund (stock and bond) is diminished, it is to have negative effect for yield of corporate bond. According to foreign investor's investment movement of previous years, hedge md were stayed at least during two years in Mexico. It means that sudden capital outflow is not to be happened at Korea. But if external factors from depreciation of yen and China's renminbi are instable, interest rate is expected to increase from capital's outflows. Third, if it is to decrease instability of foreign exchange rate from increase in surplus of future current account, credit rating's upwardness, stability of yen and renminbi, foreign exchange rate is expected to be stable. It is expected to have continuous stability from short-term interest rate to long-term interest rate in this empirical test.

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Environmental Improvement in a Welding Factory by the Jet Ventilation System (제트 환기 시스템 도입에 의한 플랜트 기자재 용접장의 환경 개선 효과 분석)

  • Lim, Jung-Ho;Lee, Tae-Gu;Moon, Seung-Jae;Lee, Jae-Heon
    • Plant Journal
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    • v.4 no.2
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    • pp.66-72
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    • 2008
  • In this inquiry, I would suggest jet ventilation system for effective elimination of welding flaw at machinery material welding shop on plant and evaluate the airstream on inner space and property of welding flaw's density through the examination. We can know outer atmosphere inflows at the speed of about 0.05m/s from western entrance in case of stopping the jet ventilation system, but airstream is accumulated on entire space. At height of worker's breathing surface(Ground Level = 1.5 m, below of GL) and welding work center, density of welding flaw on upper part(GL = 12m) is appeared 4 times higher than outer atmosphere at surplus range besides nearby of western entrance. At operation of jet ventilation system, since the smooth air current transfer at inner space and exhaust effect the wind speed is maintained at 0.932 m/s at the point of height of worker's breathing surface on inner space and it's concluded about the working conditions have been better than before operation of jet ventilation system because of that results show that inner space density of welding flaw at height of worker's breathing surface is 40.5%, and in the work shop, it is 20.3% at upper part.

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How to inflow the Fund for Initial Start-Up Companies using the On-Line Clustering Platform (초기 창업기업의 자금투자유치를 위한 온라인 클러스터링 플랫폼 연구)

  • Yoo, Soonduck;Choi, Kwangdon
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.15 no.3
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    • pp.181-189
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    • 2015
  • As a study on entrepreneurship and venture companies to support, this research is to find how to inflow the fund which is provided by private companies. This is to propose a shared platform for Information for connecting producers and consumers, corporate investors to help fund inflows to private companies and utilization of the enterprise information collected by government. Entrepreneurship support policies, as one of economy activation have a limit in the size of the support of the government therefore support continued growth through aggressive inflow of private funds is needed. It is significant to provide the environment that private funds could spill into the environment to provide for excellent start-up companies.

Development of Operating Guidelines of a Multi-reservoir System Using an Artificial Neural Network Model (인공 신경망 모형을 활용한 저수지 군의 연계운영 기준 수립)

  • Na, Mi-Suk;Kim, Jae-Hee;Kim, Sheung-Kown
    • IE interfaces
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    • v.23 no.4
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    • pp.311-318
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    • 2010
  • In the daily multi-reservoir operating problem, monthly storage targets can be used as principal operational guidelines. In this study, we tested the use of a simple back-propagation Artificial Neural Network (ANN) model to derive monthly storage guideline for daily Coordinated Multi-reservoir Operating Model (CoMOM) of the Han-River basin. This approach is based on the belief that the optimum solution of the daily CoMOM has a good performance, and the ANN model trained with the results of daily CoMOM would produce effective monthly operating guidelines. The optimum results of daily CoMOM is used as the training set for the back-propagation ANN model, which is designed to derive monthly reservoir storage targets in the basin. For the input patterns of the ANN model, we adopted the ratios of initial storage of each dam to the storage of Paldang dam, ratios of monthly expected inflow of each dam to the total inflow of the whole basin, ratios of monthly demand at each dam to the total demand of the whole basin, ratio of total storage of the whole basin to the active storage of Paldang dam, and the ratio of total inflow of the whole basin to the active storage of the whole basin. And the output pattern of ANN model is the optimal final storages that are generated by the daily CoMOM. Then, we analyzed the performance of the ANN model by using a real-time simulation procedure for the multi-reservoir system of the Han-river basin, assuming that historical inflows from October 1st, 2004 to June 30th, 2007 (except July, August, September) were occurred. The simulation results showed that by utilizing the monthly storage target provided by the ANN model, we could reduce the spillages, increase hydropower generation, and secure more water at the end of the planning horizon compared to the historical records.

Determinants of FDI in Transition Countries of Central Asia with VECM (수정오차모형을 통한 중앙아시아 체제전환국들의 FDI 결정요인 분석)

  • Narantsetseg, Narantsetseg;Choi, Chang Hwan
    • International Commerce and Information Review
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    • v.18 no.1
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    • pp.107-127
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    • 2016
  • This paper attempts to investigate determinants of foreign direct investment in transition countries of Mongolia and Central Asia five countries of Kazakhstan, Uzbekistan, Kyrgyzstan, Tajikistan and Turkmenistan. FDI inflows in this transition economies have been far increasing due to their rapid growth, GDP, gross capital formation, wage, labor force, open trading, infrastructure and natural resources as well as the factors demonstrating the economic variables and political variables of these countries by Vector Error Correction Model. The results of empirical analysis based on data from 1993 to 2013 confirmed that FDI and open trade and gross capital formation and political than GDP, wage, labor force, infrastructure and natural resources had a significant impact on Central Asia and Mongolia. In addition, if Mongolia and Central Asian five countries can maintain the country's economic growth, reduce unemployment level, achieve certain improvements in domesticating new technologies and improving skills and knowledge sphere as well as promoting stable domestic price increase, attracting and improving the FDI by paying more attention to the indicators focusing on country's GDP, wage, labor force, infrastructure and natural resource.

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Effects of Flow Acceleration on Drag Force and Wake Field of 2D Circular Cylinder (유입 유동의 가속도가 2D 원형실린더의 항력 및 후류에 미치는 영향)

  • Son, Hyun A;Lee, Sungsu;Cho, Seong Rak
    • Journal of the Society of Naval Architects of Korea
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    • v.56 no.6
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    • pp.507-514
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    • 2019
  • Computational studies of accelerating flow around 2D Circular Cylinder was performed to investigate characteristics of wake field and drag forces. Previous studies had revealed that drag on the cylindrical body in accelerating flow is much greater than that in the flow with constant velocity; however, the underlying physics on the drag increase has not been clearly investigated. In order to investigate the drag increase and its relationship with wake development, this study employed a finite-volume based CFD code, Fluent 13.0 with k-ω SST model for turbulence effects. Inflows are modeled with varied accelerations from 0.4905 to 9.81m/s2. The drag computed in the present study is in good agreement with previous studies, and clearly shows the increase compared to the drag on the body in the flow with constant velocity. The results also show that drag crisis observed at high Reynolds number in the case of the flow with constant velocity is also found in the case of accelerating flow. The analysis for wake and recirculation length shows that conventional vortex shedding does not occur even at high Reynolds number and the drag increase is larger at higher acceleration.