• 대한화학회지
• /
• 제14권1호
• /
• pp.5-12
• /
• 1970

River water and industrial waste water in Seoul were studied by means of chemical oxygen demand(COD) as an indicator for water pollution, from August 1967 to July 1968. Rivers flowing through residential and industrial areas are badly contaminated and COD of water in Han River increases as it progresses to downstream. Seasonal variation of COD showed that higher value of COD was observed in spring and lower in autumn. It is clear that the seasonal variation of COD is influenced by the precipitation. Close relationship was found between COD and population density. The lowest COD curve obtained by plotting COD values against population density and show that the curve slopes upward. The discontinuation of the curve was shown at the population density of 14,000/km$^2$; an increase in COD was acute over the population density of 14,000/km$^2$.

• 대한전기학회논문지
• /
• 제45권4호
• /
• pp.511-516
• /
• 1996

In this paper, weekly maximum power demand forecasting method in consideration of temperature estimation using a time series model was presented. The method removing weekly, seasonal variations on the load and irregularities variation due to unknown factor was presented. The forecasting model that represent the relations between load and temperature which get a numeral expected temperature based on the past 30 years(1961~1990) temperature was constructed. Effect of holiday was removed by using a weekday change ratio, and irregularities variation was removed by using an autoregressive model. The results of load forecasting show the ability of the method in forecasting with good accuracy without suffering from the effect of seasons and holidays. Percentage error load forecasting of all seasons except summer was obtained below 2 percentage. (author). refs., figs., tabs.

• 상하수도학회지
• /
• 제16권6호
• /
• pp.726-732
• /
• 2002

Pressure drop could happen in the water distribution systems due to pipe breaks or maintenance. The pressure drop causes the water service shutdown and nodal water demands should be reduced in some areas. The conventional analysis method of water distribution systems can not consider the change of nodal water demands caused by these pressure drops. This study is to investigate the variation of nodal water demands according to the nodal water pressure and its effect on the analysis of water distribution systems. For these purpose, one real water service district was selected as a study area. As a result, nodal water demand patterns according to the water pressure could be suggested. Also, we could confirm that the suggested new analysis method for the water distribution systems which considering water pressure drops could be more reliable than the conventional method.

• 한국경제지리학회지
• /
• 제14권3호
• /
• pp.286-306
• /
• 2011

본 연구는 2008년 국가경쟁력강화위원회의 발표를 필두로 현 정부가 추진하고 있는 수도권정책의 변화의 방향과 그 영향을 고찰하기 위하여 수도권정책의 변화에 민감하게 반응하는 기업의 공간수요 변화를 분석하였다. 연구내용은 수도권 정책이 기업의 입지에 미치는 영향을 살펴보고 현 정부의 수도권 규제완화 정책에 따른 기업들의 입지행태 변화 및 공간수요의 변화방향을 분석한다. 연구방법은 실증분석과 설문분석을 활용하였다. 실증분석은 1980년대 이후 통계자료를 활용하여 제조업체의 공간수요 변화추이를 분석하였다. 설문분석은 외생적 충격인 수도권 정책 변화가 기업체의 의사결정에 미치는 영향을 고찰하여 향후 기업들의 제조업용지 수요방향을 도출하였다. 연구결과 기업체들은 그동안 수도권정책으로 인하여 기업입지 결정이나 공장규모결정에 영향을 많이 받았으며 가장 큰 규제정책은 수도권정비계획법상의 권역규제와 공장총량제인 것으로 조사된다. 현 정부의 수도권규제완화로 인하여 제조업용지 수요증가가 예상된다. 특히 수도권과 충청권을 중심으로 제조업용지 수요가 증가될 것이며 강원도는 수요감소가 전망된다. 이는 수도권지역이 우리나라 중에서 가장 교통 물류 조건과 시장조건이 양호한 지역이므로 이 지역에 대한 기업선호도가 높은 까닭이다. 그러나 독자적인 경제권을 형성하고 있는 동남권이나 대경권의 경우 수도권 정책변화로 인한 영향력이 적다. 수도권지역 경우도 전체 지역에서 수요가 증가하는 것이 아니라 성장관리권역에서의 수요증가가 예상된다.

• 한국환경과학회지
• /
• 제5권6호
• /
• pp.763-770
• /
• 1996

This study was performed to analyze the variation characteristics of writer qulity, correlation analysis of water quality data at each site and among the items of water Quality data. Water quality for analysis was monthly values of water temperature, pH, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, suspended solid, 7-N and T-P checked in Daecheong Lake from January to December, 1995. It was analyzed variation of monthly water qulity was well from February to April, water temperature and COD seemed to have high correlationships at all sites. Regression equation is COD = 0.07 Water temperature +1.23 ($R^2$: 0.7616) . Results of the correlation analysis of water quality data showed that DO had high correlationships between site 1 and site 2, BOD did site 1 and 3, COD did site 1 and 2, 55 did site 5 and 6, 7-N did 2 and 3, 7-P did site 4 and 6. Regression equations for estimate of water quality data are as follows. $DO_1$=4.46+0.59 DO, ($R^2$=0.8868), $BOD_1$ = 0, 52+0.63 BOD3 ($R^2$ = 0.6390) $COD_2$ = 0.44+0.71 $COD_1$ ($R^2$ = 0.9183), SS6 = 0.89+0.7055.($R^2$ = 0.9155) $TN_3$ = 0.151 +0.886 $TN_2$ ($R^2$ = 0.9415), $TP_4$ = 0.004+5.758 $TP_6$ ($R^2$ = 0.9669)

• 국제초고층학회논문집
• /
• 제2권4호
• /
• pp.331-340
• /
• 2013

The main topic of this paper is to show a possibility of indoor air quality enhancement and the fan energy savings in underground parking facilities by applying the demand-controlled ventilation (DCV) strategy based on the real-time variation of the traffic load. The established ventilation rate is estimated by considering the passing distance, CO emission rate, idling time of a vehicle, and the floor area of the parking facility. However, they are hard to be integrated into the real-time DCV control. As a solution to this problem, the minimum ventilation rate per a single vehicle is derived in this research based on the actual ventilation data acquired from several existing underground parking facilities. And then its applicability to the DCV based on the real-time variation of the traffic load is verified by simulating the real-time carbon monoxide concentration variation. The energy saving potentials of the proposed DCV strategy is also checked by comparing it with those for the current underground parking facility ventilation systems found in the open literature.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2004년도 봄 학술발표회 논문집
• /
• pp.417-422
• /
• 2004

It is the challenging task to predict seismic demand for structural design. In current seismic design provisions such as UBC, NEHRP, ATC 3-06, the seismic demand is calculated using the response spectrum with response modification factor (R). This paper investigates variability of seismic demand according to selecting the earthquake ground motion groups. Different Earthquake sets used by Miranda, Riddell and Seed selected were used in this study. Earthquake sets selected by authors include 62 sets of near field ground motion and 19 sets one pulse ground motion. Linear Elastic Response Spectrum (LERS), the variation of performance points of calculated by Capacity Spectrum Method (CSM) were considered with respect to the different sets of earthquake ground motions.

• 한국경영과학회지
• /
• 제34권4호
• /
• pp.91-112
• /
• 2009

The bullwhip effect means the phenomenon of increasing demand variation as moving UP to the upstream in the supply chain. Therefore, it is recognized that the bullwhip effect is problematic for effective supply chain operations. In this paper, we exactly quantifies the bullwhip effect for the case of stochastic lead time and seasonal demand in two-echelon supply chain where retailer employs a base-stock policy considering SARMA demand processes and stochastic lead time. We also investigate the behavior of the proposed measurement for the bullwhip effect with autoregressive and moving average coefficient, stochastic lead time, and seasonal factor.

• 한국농공학회논문집
• /
• 제54권6호
• /
• pp.39-44
• /
• 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.

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