• Title/Summary/Keyword: Demand and Supply Curves

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Evaluation of Irrigation Vulnerability Characteristic Curves in Agricultural Reservoir (농업용 저수지 관개 취약성 특성 곡선 산정)

  • Nam, Won-Ho;Kim, Taegon;Choi, Jin-Yong;Kim, Han-Joong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.54 no.6
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    • pp.39-44
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    • 2012
  • Water supply capacity and operational capability in agricultural reservoirs are expressed differently in the limited storage due to seasonal and local variation of precipitation. Since agricultural water supply and demand basically assumes the uncertainty of hydrological phenomena, it is necessary to improve probabilistic approach for potential risk assessment of water supply capacity in reservoir for enhanced operational storage management. Here, it was introduced the irrigation vulnerability characteristic curves to represent the water supply capacity corresponding to probability distribution of the water demand from the paddy field and water supply in agricultural reservoir. Irrigation vulnerability probability was formulated using reliability analysis method based on water supply and demand probability distribution. The lower duration of irrigation vulnerability probability defined as the time period requiring intensive water management, and it will be considered to assessment tools as a risk mitigated water supply planning in decision making with a limited reservoir storage.

Traffic Analysis Model for Exit Ramp Congestion at Urban Freeway (고속도로 진출램프 대기행렬 발생 현상 분석모형 개발)

  • Jeon, Jae-Hyeon;Kim, Young-Chan
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.9 no.3
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    • pp.30-40
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    • 2010
  • The freeway congestion is largely generated by a mainline spillover of the exit ramp queue. So it is necessary to study for modeling of the phenomenon and applying the model. In this study, the authors evaluated applicability of the Supply-Demand model, which can express traffic flow for the freeway by applying flexibly supply and demand curves for capacity of the freeway. First the authors proposed methods processing input data required in the Supply-Demand model, such as sending & receiving functions and time-varying capacity constraints for the freeway mainline. After modeling the Supply-Demand application model, the authors applied the model to the site including congested Hongeun exit ramp in Seoul Ring-road, and improved the model by adjusting application techniques and calibrating parameters. The result of the analysis showed that the Supply-Demand model yielded a queuing pattern and queue location similar to them observed in the field data, and applicability of the Supply-Demand model was varified.

The Changing Patterns of Demand-Supply and Role of Mineral Resources in Economic Growth during Industrialization of the Republic of Korea (한국공업화과정(韓國工業化過程)에서의 광물자원(鑛物資源)의 수급구조변화(需給構造變化)와 경제성장(經濟成長)에 있어서의 역할(役割))

  • Yun, Suckew
    • Economic and Environmental Geology
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    • v.18 no.1
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    • pp.65-92
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    • 1985
  • A total of 12 mineral commodities significant in domestic output, economy and/or strategy of the Republic of Korea are chosen to examine the structural changes in production and demand-supply of these minerals during the last two decades of her industrialization. These include iron and manganese ores as the raw materials for iron and steel making, copper, zinc and tungsten ores among other non-ferrous metallic minerals, limestone (cement), kaolin, talc, pyrophyllite and graphite among other non-metallic minerals, and anthracite coal as the only domestic source of fossil energy. These are reviewed historically in time-series based on the statistical data which are tabulated and graphed in terms of domestic output, export, import, apparent demand-supply, its increasing rate, and self-sufficiency rate of each commodity. The increasing rates of demand-supply (IRDS) of some more important commodities are compared with those of Gross Domestic Production (GDP) and Economic Growth Rate (EGR) to evaluate how the IRDS contributed to the GDP and EGR. The major results revealed are as follows: Among the 12 commodities, the domestic output of 8 commodities appeared to have grown with steady upward trends: they are ores of lead, zinc and tungsten, limestone (cement), kaolin, talc, pyrophyllite and anthracite coal. Two commodities, ores of iron and copper, continued with unchanging or slightly declining trends and varied fluctuations, in spite of their cardinal importance to the heavy industry and strategy of Korea. The remaining two, graphite and manganese ore, have gradualy declined in domestic output in which the former has still enough resource potential but the latter has not and virtually ceased its domestic output. Trade patterns for mineral commodities in the Republic of Korea during the last two decades have changed greatly, being marked by a shift from mineral-exporting to mineral importing, mainly because of increasing consumption of mineral raw materials for industrialization rather than beceuse of decreasing output of domestic mineral commodities in quantity. In terms of trade patterns, the 12 commodities concerned in this study can be classified into the following four groups. The 1st group - ores of lead and tungsten have only been exported without imports. The 2nd group - amorphous graphite, and pyrophyllite have mainly been exported but partly been imported. The 3rd group - kaolin, talc and crystalline graphite have equally been exported and imported, but quantity of imports have rapidly been increased with time. The 4th group - ores of iron, manganese and zinc have shifted from exports to imports during the industrialization, particularly owing to the initiation of iron and steel making by the Pohang Iron and Steel Company in the middle 1970' s and the new establishment of the Onsan Zinc Refinery in the late 1970' s. All of the 12 commodities under considerations were far above 100% in self-sufficiency rate before or in the early 1960' s. Recently, however, most of them have been declined to below 100% except for those of limestone (cement) and pyrophyllite. It is particularly serious to identify that the self-sufficiency rates of the three important metallic minerals, iron, copper and manganese ores in 1982 appeared to be 5.1%, 0.5%, and 0.01%, respectively. The average self-sufficiency rate of the total domestic minerals produced in 1982 was 14.4% (in value) for that year. Mining industry appeared to be extremely high in its intermediate demand rate whereas its intermediate input rate to be quite low indicating that mineral raw materials have been exerted strong forward linkage effects upon the other industries rather than backward linkage effects. In comparing the curves of increasing rates of demand-supply of several major minerals - iron ore, manganese ore, copper ore, limestone (cement), kaolin, and anthracite coal - with those of Gross Domestic Production and Economic Growth Rate drawn on every graph, it is clearly shown that the curves of increasing rates of demand-supply comprise around 6 to 7 periods of cycles which roughly harmonious with those of the curves of GDP and EGR, except for the curve of anthracite coal of which the configuration seems to have resulted from the (artificial) government's mineral policy rather than from economic free market mechanism. The harmonic feature of these curves well suggests that the increasing rates of demand-supply of major minerals have been significantly contributed to the GDP and EGR. In addition, the wider amplitudes of the iron, manganese and copper curves than those of the limestone (cement) and kaolin curves indicate that the contribution of the former, metallic commodities, has been greater than that of the latter, non-metallic commodities.

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Development of Operation Rules in Agricultural Reservoirs using Real-Time Water Level and Irrigation Vulnerability Index (실시간 저수위 및 용수공급 취약성 지표를 활용한 농업용 저수지 운영 기준 개발)

  • Nam, Won Ho;Choi, Jin Yong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.55 no.6
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    • pp.77-85
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    • 2013
  • The efficient operation and management strategies of reservoirs in irrigation periods of drought events are an essential element for drought planning and countermeasure. Korea Rural Community Corporation has developed the real-time water level observation system of agricultural reservoirs to efficiently operate reservoirs, however, it is not possible to predict drought conditions, and only provides information of current situation. Hence, it is necessary to evaluate accurate irrigation vulnerability and efficiently reservoir operation rules using current water level. In this paper, the improvement methods of reservoir operation planning were developed with water supply vulnerability characteristic curves comparing to automatic water gauge at agricultural reservoirs. The 11 reservoirs were simulated applying the reservoir operation rules which was determined by irrigation vulnerability characteristic curves criteria and real time water level, and evaluated water supply situation in 2012 year. The analysis of results can be identified probabilistic possibility of water supply failures compared with the existing reservoir operation criteria. These results of efficient reservoir operation rules can be achieved enable irrigation planners to optimally manage available water resources for decision making, and contributed to maintain the water supply according to demand strategy for agricultural reservoirs management.

Stochastic Reservoir Model for the Estimation of Optimal Water Supply (적정 용수 공급량 산정를 위한 추계학적 저수용량 모델)

  • 장인수;박정규;유일준
    • Journal of Environmental Health Sciences
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    • v.21 no.1
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    • pp.29-38
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    • 1995
  • The purpose of this study is to improve the present methodology-for the estimation of optimal water supply from an impounding reservoir. The stochastic reservoir storage model presented in this paper is believed to be rational in that. the probability of reservoir depletion (return period) is to be calculated for the various monthly demands and storage capacities. The monthly flows are used to derive the reservoir storage capacity-monthly demand-probability curves at Dalcheon damsite and Hongcheon damsite in Han river basin.

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A Study on the Estimations Method of Demand-Side Management Cost Per kW and/or kWh to Find Reasonable Load Factor (전력시스템 적정 부하율 산정을 위한 단위당 수요관리비용 추정 방안 연구)

  • Hwang, Sung-Wook;Kim, Jung-Hoon;Jung, Young-Beom;Yoon, Yong-Beum
    • Proceedings of the KIEE Conference
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    • 2007.11b
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    • pp.26-28
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    • 2007
  • To estimate reasonable load factor of power system both supply side and demand side of views should be considered. In the case of this study the demand side is considered and it is supposed that load curves depends on the load factor. The key point of this study is that the cost of demand-side management program per kW and/or kWh should be calculated.

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Optimal Operation of Single Multi-Purpose Reservoir (단일다목적 저수지의 최적운영)

  • 이순택;이수식
    • Water for future
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    • v.18 no.4
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    • pp.347-359
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    • 1985
  • This study aims at the development of DP-Model for the establishment of monthly optimal operation policy of single multi-puppose reservoir by which the water demand of downstream can be satisfied under the various physical constraints. Series, A. B. C. of inflow are selected out of future monthly inflow data which are simulated form the past monthly average inflow of Andong dam site. the neight possible alternatives in each inflow series are established in order that Andong dam can supply the water demand of Nagdong main stream of 30% to 100%. Nextly, the reservoir rule curves is derived for each alternative by the detailed seguential analysis of stroage, future inflow and water demand based on the reservoir continuite equation. Then, and alternative which can satisfy the objective function of system based on the rule curves in the exteream is determined as an optimal operation policy from the application of developed DP=Model.

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Estimation of Induced Highway Travel Demand (도로교통의 유발통행수요 추정에 관한 연구)

  • Lee, Gyu-Jin;Choe, Gi-Ju
    • Journal of Korean Society of Transportation
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    • v.24 no.7 s.93
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    • pp.91-100
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    • 2006
  • Travel Demand Forecasting (TDF) is an essential and critical process in the evaluation of the highway improvement Project. The four-step TDF Process has generally been used to forecast travel demand and analyze the effects of diverted travel demand based on the given Origin-Destination trips in the future. Transportation system improvements, however, generate more travel, Induced Travel Demand (ITD) or latent travel demand, which has not been considered in the project evaluation. The Purpose of this study Is to develop a model which can forecast the ITD applied theory of economics and the Program(I.D.A) which can be widely applied to project evaluation analysis. The Kang-Byun-Book-Ro expansion scenario is used to apply and analyze a real-world situation. The result highlights that as much as 15% of diverted travel demand is generated as ITD. The results of this study are expected to improve reliability of the project evaluation of the highway improvement Project.

A study on the military size of conscript or recruit under unified Korea (통일 한국의 징병제와 모병제 하의 병력규모에 관한 연구)

  • Cho, Hong Yong
    • Journal of the Korean Data and Information Science Society
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    • v.28 no.6
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    • pp.1521-1538
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    • 2017
  • There have been many researches on the optimal military size of unified Korea. However, most studies have used qualitative evaluation methods using subjective data. In addition, two studies incorporating statistical methodologies fail to derive appropriate results due to errors in selection of variables and the use of subjective data. Therefore, in this study, we use the ratio data instead of the country specific defense related data for 30 major countries in the world. We applied the logic of demand and supply of economics. The supply equations were produced by regression linear equation of the active ratio and defense ratio. The demand equations were produced as an inverse curves using the same coordinate system as the supply equation. With such a method, we estimated the appropriate military size and defense ratio for each of conscript and recruit system in unified Korea about 20 - 30 years later.

Power demand pattern analysis for electric appliances in residential and commercial building (주택 및 사무용 빌딩 내 전기기기의 전력 수요 패턴 분석)

  • Noh, Sung-Jun;Lee, Soon-Jeong;Lee, Sang-Woo;Kim, Kwang-Ho
    • Journal of Industrial Technology
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    • v.30 no.A
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    • pp.9-15
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    • 2010
  • Recently, Smart Grid is a emerging topic in power and communication industry. Smart Grid refers to a evolution of the electricity supply infrastructure that monitors, protects, and intelligently optimize the operation of the interconnected elements including various type of generators, power grid, building/home automation system and end-use consumers. In order to successful implementation of Smart Grid, energy management function will be the key factor that coordinates and optimally controls the various loads according to the operating condition and environments, and the load patterns in residential and commercial building will be required as fundamental element for load management. In this study, we collects many types of energy usage data of electric appliances, analyze their load curves, and make the general load patterns for electrical appliance.

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