• Title/Summary/Keyword: Daily Operation

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Siniulating Daily Inflow and Release Rates for Irrigation Reservoirs(III) - Model Application to Dafly Reservoir Operations - (관개용 저수지의 일별 유입량과 방류량의 모의 발생 (III) -저수지 모의조작 모형의 응용-)

  • 김현영;박승우
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.30 no.3
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    • pp.95-105
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    • 1988
  • This study refers to the development of a hydrologic model simulating daily inflow and release rates for irrigation reservoirs. A daily - based model is needed for adequate operation of an irrigation reservoir sufficing the water demand for paddy fields which is closely related to meteorological conditions. And the objective or this study is to develop a Daily Irrigation Reservoir Operation Model(DIROM) combining the inflow and the release models which depicts the daily water level fluctuations of an irrigation reservoir, and to evaluate the applicability of the model. DIROM was applied to four reservoirs and daily water levels were simulated and compared to the observed data. The model behaviour was also compared with that of a ten - day based model, Reservoir Operation Study(ROS) which has been applied for determining the design capacity of reservoirs. Various combinations of measured and simulated inflow and release rates for tested reservoirs were used to define the daily water level fluctuations. Simulated release rates and measured inflow data resulted in larger errors, and simulated inflow and release rates produced the smallest errors in water level comparison. Two resevoir operation models, DIROM and ROS were applied to the same reservoir and the simulation results compared. The computational errors of DIROM ware smaller than those of ROS, and DIROM was more sensitive to meteorological conditions. DIROM demonstrated its potenial applicability in water management and operation.

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Improvement of the Load Forecasting Accuracy by Reflecting the Operation Rates of Industries on the Consecutive Holidays (특수일 조업률 반영을 통한 전력수요예측 정확도 향상)

  • Lim, Nam-Sik;Lee, Sang-Joong
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.7
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    • pp.1115-1120
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    • 2016
  • This paper presents the daily load forecasting for special days considering the rate of operation of industrial consumers. The authors analyzed the power consumption pattern for both the special and ordinary days according to the contract power classification of industrial consumers, and selected 400~600 specific consumers for which the rates of operation during special days are needed. Load forecasting for 2014 special days considering the rate of operation of industrial consumers showed a noticeable improvement on forecasting error of daily peak demand, which proved the effectiveness of the survey for the rates of operation during special days of industrial consumers.

Development of Simulation Model Based Optimal Start and Stop Control Daily Strategy (시뮬레이션 모델기반 냉난방 설비 일별 최적 기동/정지 제어기법 개발)

  • Lee, Chanwoo;Koo, Junemo
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.14 no.1
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    • pp.16-21
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    • 2018
  • This work aims to develop a platform to investigate the effect of operation schedules on the building energy consumption and to derive a simulation model based optimal start and stop daily strategy. An open-source building energy simulation tool DOE2 is used for the engine, and the developed simulation model is validated using ASHRAE guideline 14. The effect of late-start/early-stop operation of HVAC system on the daily building energy consumption was analyzed using the developed simulation model. It was found that about 10% of energy consumption cut was possible using the control strategy for an hour of advance of the stop operation, and about 3% per an hour of delay of the start operation.

COMS Normal Operation for Earth Observation Mission

  • Cho, Young-Min
    • Korean Journal of Remote Sensing
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    • v.29 no.3
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    • pp.337-349
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    • 2013
  • Communication Ocean Meteorological Satellite (COMS) for the hybrid mission of meteorological observation, ocean monitoring, and telecommunication service was launched onto Geostationary Earth Orbit on June 27, 2010 and it is currently under normal operation service on $128.2^{\circ}$ East of the geostationary orbit since April 2011. In order to perform the three missions, the COMS has 3 separate payloads, the meteorological imager (MI), the Geostationary Ocean Color Imager (GOCI), and the Ka-band antenna. The MI and GOCI perform the Earth observation mission of meteorological observation and ocean monitoring, respectively. For this Earth observation mission the COMS requires daily mission commands from the satellite control ground station and daily mission is affected by the satellite control activities. For this reason daily mission planning is required. The Earth observation mission operation of COMS is described in aspects of mission operation characteristics and mission planning for the normal operation services of meteorological observation and ocean monitoring. And the first one-year normal operation results after the In-Orbit-Test (IOT) are investigated through statistical approach to provide the achieved COMS normal operation status for the Earth observation mission.

CONSTRUCTING DAILY 8KM NDVI DATASET FROM 1982 TO 2000 OVER EURASIA

  • Suzuki Rikie;Kondoh Akihiko
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.18-21
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    • 2005
  • The impact of the interannual climatic variability on the vegetation sensitively appears in the timing of phenological events such as green-up, mature, and senescence. Therefore, an accurate and temporally high-resolution NDVI dataset will be required for analysis on the interannual variability of the climate-vegetation relationship. We constructed a daily 8km NDVI dataset over Eurasia based on the 8km tiled data of Pathfinder A VHRR Land (PAL) Global daily product. Cloud contamination was successfully reduced by Temporal Window Operation (TWO), which is a method to find optimized upper envelop line of the NDVI seasonal change. Based on the daily NDVI time series from 1982 to 2000, an accurate (daily) interannual change of the phenological events will be analyzed.

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Application of peak load for industrial water treatment plant design (공업용수 정수장 설계시 첨두부하 적용방안)

  • Kim, Jinkeun;Lee, Heenam;Kim, Dooil;Koo, Jayong;Hyun, Inhwan
    • Journal of Korean Society of Water and Wastewater
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    • v.30 no.3
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    • pp.225-231
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    • 2016
  • Peak load rate(i.e., maximum daily flow/average daily flow) has not been considered for industrial water demand planning in Korea to date, while area unit method based on average daily flow has been applied to decide capacity of industrial water treatment plants(WTPs). Designers of industrial WTPs has assumed that peak load would not exist if operation rate of factories in industrial sites were close to 100%. However, peak load rates were calculated as 1.10~2.53 based on daily water flow from 2009 to 2014 for 9 industrial WTPs which have been operated more than 9 years(9-38 years). Furthermore, average operation rates of 9 industrial WTPs was less than 70% which means current area unit method has tendency to overestimate water demand. Therefore, it is not reasonable to consider peak load for the calculation of water demand under current area unit method application to prevent overestimation. However, for the precise future industrial water demand calculation more precise data gathering for average daily flow and consideration of peak load rate are recommended.

Analysis on short-term decay heat after shutdown during load-follow operation with seasonal and daily scenarios

  • Hwang, Dae Hee;Kim, Yonghee
    • Nuclear Engineering and Technology
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    • v.54 no.10
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    • pp.3878-3887
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    • 2022
  • For the future energy-mix policy for carbon neutrality, demand for the capability of load-follow operation has emerged in nuclear power plants in order to accommodate the intermittency of renewable energy. The short-term decay heat analysis is also required to evaluate the decay heat level varied by the power level change during the load-follow operation, which is a very important parameter in terms of short-term decay heat removal during a grace time. In this study, the short-term decay heat level for 10 days after the shutdown was evaluated for both seasonal and daily load-follow cases. Additionally, the nuclide-wise contribution to the accumulated decay heat for 10 days was analyzed for further understanding of the short-term decay heat behavior. The result showed that in the seasonal case, the decay heat level was mainly determined by the power level right before the shutdown and the amount of each nuclide was varied with the power variation due to the long variation interval of 90 days. Whereas, in the daily case, the decay heat level was strongly impacted by the average power level during operation and meaningful mass variations for those nuclides were not observed due to the short variation interval of 0.5 days.

Operation Rule of Irrigation Reservoir (灌漑 貯水池의 利水 管理 方法)

  • Kim, Tae-Cheol;No, Jae-Gyeong;Park, Seung-Gi
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.34 no.1
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    • pp.33-40
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    • 1992
  • Up to now, monthly water balance analysis has been dominantly used for the water resources planning. But, it is more reasonable to explain the variation of spatial and temporal distribution of water by the daily water balance model with daily streamflow data. Since we are recently facing the problems of regional unbalance of water quantity, and of multiuse of irrigation water, and of deterioration of water quality, it is urgently needed to develop the daily water balance model to solve those problems and establish the rational plannings of agricultural water resources. In the circumstances, Daily water Balance(DAWABA) model for irrigation reservoirs was developed and the operation rule of irrigation resorvoir during drought season was established.

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Characteristics of 5 kW Class Proton-Exchange-Membrane Fuel Cell(PEMFC) Stack according to the Long-Term Operation (장기운전에 따른 5 kW급 고분자 전해질 연료전지 스택의 특성)

  • Kim, Jae-Dong;Lee, Jung-Woon;Park, Dal-Ryung
    • Journal of the Korean Institute of Gas
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    • v.11 no.3
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    • pp.40-43
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    • 2007
  • The performance of PEMFC stack can be improved significantly by optimizing the design and operating conditions. As a result, the performance of daily operation showed slight deviation (0.02-0.9%) after accumulated DSS operation for 500 hrs but the stack performance was stable. Therefore, it is confirmed that it would be improved the life-time of stack and operation reliability for the commercialization of PEMFC system.

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A Study on The Factors Affecting the Managerial Performance of Hospitals (병원경영의 수익성 결정요인에 관한 연구)

  • Chung Bhum-Suk
    • Management & Information Systems Review
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    • v.17
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    • pp.107-133
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    • 2005
  • The purpose of this study was to analyze a trend of profitability classified by characteristics of hospitals and to analyze related factors. The data for this study were derived from survey material conducted by the Korean Hospital Association on 33 hospitals in Korea between 1993 and 2002. Profitability was measured in the aspect of investment profit rate and operation profit rate with net profit to total assets, normal profit to total assets and operating margin to gross revenue as dependent variables. Independent variables were classified by general factors (ownership, number of beds, period of establishment, region), financial factors (total asset turnover, liabilities to total assets, current ratio, fixed ratio, inventories turnover, personnel costs per operation profit, material costs per operation profits), composition of manpower and facilities(personnel and area per beds), productivity index(the number of daily patients per medical doctor, the number of daily patients per nurse), the score of quality assurance activities. First, Concerning the specialists per beds or area per beds and profitability of hospitals there was not statistically significant. Second, Those hospitals having the most daily patients per nurse had significantly higher profitability than the others, but the number of daily patients per medical doctor had little effect on the profitability. Thirds, Those hospitals having a higher proportion total asset turnover tended to show significantly higher profitability compared to other hospitals, but the liabilities to total assets and liquidity ratio had a little difference to the profitability. Those hospitals having a higher proportion personnel costs per operation profit and material costs per operation profits tended to show significantly lower hospital profitability compared to other hospitals. Fourth, In regression analysis, hospital profitability had negative relationship with personnel costs per operation profit or material costs per operation profits. While it had positive relationship with total asset turnover, the number of daily patients per nurse. In conclusion, private hospitals had higher profitability than that of public hospitals. Though factors related to profitability of hospital were different according to ownership, it is important for securing appropriate profitability by operating appropriate number of nurse, raising total asset turnover, and reducing personnel costs, material costs per operation profits. This study can be used as a baseline data for planning of hospital management. But the study may be limited in that the results cannot be generalized due to its small sample size. However, this longitudinal observation of 33 hospitals over ten year period has significant merit alone.

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