• 대한전기학회논문지
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• 제31권7호
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• pp.1-10
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• 1982

This paper derives the algorithm to estimate the operating cost, its marginal cost, and the reliability indices for the long term planning of power system. Treating the load duration curve and the system in the stochastic sense takes the place of the inverted load duration curve, effective load duration curve, and the numerical integration in the conventional methods. The time and accuracy of computation are substantially improved due to the fact that all expressions are represented by simple analytic form instead of the existing recursive form.

• 한국구조물진단유지관리공학회 논문집
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• 제9권1호
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• pp.189-196
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• 2005

임펄스 비와 하중최대치의 비로 작성된 손상곡선을 이용하여 충격하중의 임펄스와 하중의 크기가 구조물의 거동에 미치는 영향을 분석하였다. 단기에 종료하는 충격하중의 경우 관성력의 영향으로 하중의 크기보다는 임펄스가 구조물 손상에 주요변수가 되며, 관성력을 극복할 충분한 시간을 갖는 장기하중이 작용하는 경우에는 임펄스보다는 하중의 크기가 구조물 손상에 주요변수가 된다. 지반충격에 의한 구조물의 손상은 단기인 경우에는 지반의 최대입자속도가 그러나 장기인 경우에는 최대입자가속도가 손상의 주요 변수가 된다.

• 한국물환경학회지
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• 제29권3호
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• pp.343-353
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• 2013

Flow duration curve (FDC) can be developed by linking the daily flow data of stream flow monitoring network to 8-day interval flow data of the unit watersheds for the management of Total Maximum Daily Loads. This study investigated the applicable method for the development of long term FDC with the selection of the stream flow reference sites, and suggested the development of the FDC in 4 river basins. Out of 142 unit watersheds in 4 river basins, 107 unit watersheds were shown to estimate daily flow data for the unit watersheds from 2006 to 2010. Short term FDC could be developed in 64 unit watersheds (45%) and long term FDC in 43 unit watersheds (30%), while other 35 unit watersheds (25%) were revealed to have difficulties in the development of FDC itself. Limits in the development of the long term FDC includes no stream monitoring sites in certain unit watersheds, short duration of stream flow data set and missing data by abnormal water level measurements on the stream flow monitoring sites. To improve these limits, it is necessary to install new monitoring sites in the required areas, to keep up continuous monitoring and make normal water level observations on the stream flow monitoring sites, and to build up a special management system to enhance data reliability. The development of long term FDC for the unit watersheds can be established appropriately with the normal and durable measurement on the selected reference sites in the stream flow monitoring network.

• 대한전기학회논문지:전력기술부문A
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• 제55권12호
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• pp.570-575
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• 2006

This paper develops methodology in order to consider CHP(Combined Heat and Power) capacity in the Basic Plan of Long Term Electricity Supply & Demand. We develop generating cost of CHP considering electric and heat. Also we develop mixed load duration curve which includes the electric load and heat load and then apply CHP capacity to SCM(Screening Curve Method) considering CHP feature. Accordingly, it decide the optimal CHP capacity in the Basic Plan of Long Term Electricity Supply & Demand. Also, We perform the sensitivity analysis according to cost variation.

• 한국지리정보학회지
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• 제24권3호
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• pp.41-57
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• 2021

본 연구는 대청호 상류에 있는 서화천 유역을 대상으로 SWAT(Soil and Watershed Assessment Tool) 모형을 이용한 수질 관리 대책 적용 및 부하지속곡선(LDC, Load Duration Curve)을 이용한 대책의 효율을 평가하였다. 수질 관리 대책으로는 인공습지, 방치 축분 저감, 비닐하우스 유출량 저감, 생태하천 복원, LID(Low Impact Development) 기술 적용, 점오염원 관리를 적용하였다. 적용된 기술은 부하지속곡선을 통해 유황별 목표 수질 초과율 및 부하량 저감 정도를 이용하여 수질 개선대책의 효율을 평가하였다. 부하지속곡선은 SWAT를 이용하여 장기 유량지속곡선(FDC, Flow Duration Curve)을 만들고 목표 수질을 곱하여 작성하였으며 목표 수질은 서화천 하류에 있는 옥천천 수질 관측지점의 10년간 자료를 사용하여 60분위에 해당하는 값을 목표 수질로 설정하였다. 본 연구를 통하여 여러 가지 수질 대책을 SWAT 모형을 통해 적용 가능성을 확인할 수 있으며 부하지속곡선을 통하여 유황에 따른 시기별 적용 가능성을 검토할 수 있었다.

• 한국물환경학회지
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• 제29권6호
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• pp.762-776
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• 2013

Load duration curve was applied to determine important water quality parameter control term for improvement of Paldang lake water quality. Load duration curve was analyzed with long term data from 1985 to 2012 including water quality, flow rate and climate state of Paldang water environment. From the result of flow rate patterns of paldang lake, differences between high and low flow rate of each year showed tendency of increase because rainfall characteristics of paldang lake watershed were changed by climate exchange. Both of land use state of upper Paldang lake watershed and number of limit excess from load duration curve indicated that seasonal action related with land use such as agricultural fertilizer distribution in upper watershed affected Paldang lake water quality. So focused BOD (biological oxygen demand) management during spring season from march to June is required to control organic materials in Paldand lake. The main affecting factor of TOC (total organic carbon) increase in Paldang lake was initial rainfall after march. T-N (total nitrogen) kept increasing during research period, so enhancement of T-N standard is needed to T-N control. Initial rainfall and increase of temperature during spring season from March to June showed a positive correlation with TP (total phosphorus) and Chl-a, respectively.

• Structural Engineering and Mechanics
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• 제49권2호
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• pp.261-271
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• 2014

This paper reported an experimental study on creep behaviors of PVB and Ionoplast laminated glass (LG) under load duration of 30 days. The tests were carried out in room temperature ($23^{\circ}C$). The study revealed that after sustaining loads for 30 days, the mid-span deflection of PVB LG increased by almost 102% compared with its short term deflection, while that of Ionoplast LG approximately increased by 14%; composite effects between two glass plies in PVB LG gradually reduced with time, but did not fully vanish at the 30th day; two glass plies in Ionoplast LG on the other hand was able to withstand loads as an effective composite section during the entire loading period; the creep behaviors of both LG were not finished yet at the 30th day. In addition to this, also studied was the varying of the bending stresses of PVB and Ionoplast LG under load duration of 2 hours. The tests were carried out in ambient temperatures of $30^{\circ}C$, $50^{\circ}C$ and $80^{\circ}C$ respectively. It was found that under a given load, although the bending stresses of both LG increased with increasing temperature, for PVB LG the increasing rate of the bending stress decreased with increasing temperature, while for Ionoplast LG the increasing rate of the bending stress increased with increasing temperature.

• 한국농공학회지
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• 제44권3호
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• pp.92-100
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• 2002

The advent or high-strength steel has enabled the arch structures to be relatively light, durable and long-spanned by reducing the cross sectional area. On the other hand, the possibility of collapse may be increased due to the slender members which may cause the stability problems. The limit analysis to estimate the ultimate load is based on the concept of collapse mechanism that forms the plastic zone through the full transverse sections. So, it is not appropriate to apply it directly to the instability analysis of arch structures that are composed with compressive members. The objective of this study is to evaluate the ultimate load carrying capacity of the parabolic arch by using the elasto-plastic finite element model. As the rise to span ratio (h/L) varies from 0.0 to 0.5 with the increment of 0.05, the ultimate load has been calculated fur arch structures subjected to uniformly distributed vertical loads. Also, the disco-elasto-plastic analysis has been carried out to find the duration time until the behavior of arch begins to show the stable state when the estimated ultimate load is applied. It may be noted that the maximum ultimate lead of the parabolic arch occurs at h/L=0.2, and the appropriate ratio can be recommended between 0.2 and 0.3. Moreover, it is shown that the circular arch may be more suitable when the h/L ratio is less than 0.2, however, the parabolic arch can be suggested when the h/L ratio is greater than 0.3. The ultimate load carrying capacity of parabolic arch can be estimated by the well-known formula of kEI/L$^3$where the values of k have been reported in this study. In addition, there is no general tendency to obtain the duration time of arch structures subjected to the ultimate load in order to reach the steady state. Merely, it is observed that the duration time is the shortest when the h/L ratio is 0.1, and the longest when the h/L ratio is 0.2.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.652-656
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• 2007

The major streams in South Korea have established the TMDL(Total Maximum Daily Loads) regulation for just 4 years. Traditional concepts in water quality management in South Korea are based upon the selection of a design streram flow which is 10-year averged flow exeedance probability 75%(Q275). That is, a single flow value based upon average long term flow conditions is chosen for application in dilution calculations, permit design, water quality modeling, etc. While these TMDLs seems to satisfy the requirement of the target water quality regulations, they have contributed little to any watershed/waterbody assessment and restoration plans. These types of TMDLs do little to characterize the problems the TMDLs are intended to address. For TMDLs to be more beneficial in the assessment and implementation process, TMDLs should reflect adequate water quality across flow conditions rather than at a single flow value such as average daily flow. In this paper, we developed LDC (load duration curve) methodology for theevaluation of Korean TMDL evaluation based on watershed scaled, physically based on SWAT(Soil and Water Assessment Tool) model.

• 한국환경과학회지
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• 제26권8호
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• pp.939-953
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• 2017

For the development of flow duration curves for the management of 41 Total Maximum Daily Load (TMDL) units of the Nakdong River basin, first, an equation for estimating daily flow rates as well as the level of correlation (correlation and determination coefficients) was extrapolated through regression analysis of discrete (Ministry of Environment) and continuous (Ministry of Land, Infrastructure and Transportation) measurement data. The equation derived from the analysis was used to estimate daily flow rates in order to develop flow duration curves for each TMDL unit. By using the equation, the annual flow duration curves and flow curves, for the entire period and for each TMDL unit of the basin, were developed to be demonstrated in this research. Standard flow rates (abundant-, ordinary-, low- and drought flows) for major flow duration periods were calculated based on the annual flow duration curves. Then, the flow rates, based on percentile ranks of exceedance probabilities (5, 25, 50, 75, and 95%), were calculated according to the flow duration curves for the entire period and are suggested in this research. These results can be used for feasibility assessment of the set values of primary and secondary standard flow rates for each river system, which are derived from complicated models. In addition, they will also be useful for the process of implementing TMDL management, including evaluation of the target level of water purity based on load duration curves.