• 전기학회논문지
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• 제58권9호
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• pp.1695-1699
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• 2009

This paper analyzed the characteristics of the demand of electric power in Jeju by year, day. For this analysis, this research used the correlation between the changes in the temperature and the demand of electric power in summer, and cleaned the data of the characteristics of the temperatures, using the coefficient of correlation as the standard. And it proposed the algorithm of forecasting the short-term electric power demand in Jeju, Therefore, in the case of summer, the data by each cleaned temperature section were used. Based on the data, this paper forecasted the short-term electric power demand in the exponential smoothing method. Through the forecast of the electric power demand, this paper verified the excellence of the proposed technique by comparing with the monthly report of Jeju power system operation result made by Korea Power Exchange-Jeju.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 추계학술대회 논문집
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• pp.206-207
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• 2016

The intermittent characteristics of wind power (WP) may have negative effect on grid stability, especially in weak grid. WP fluctuation rate can be reduced by using energy storage system (ESS) through charging and discharging. The operation of ESS will decide its losses and lifetime of batteries. From this point, this paper proposes WP smoothing control by using short-term average of WP. In this case, the ESS will only operate at high WP fluctuation rate. Then, the output power of ESS will be estimated by short-term average value. The effectiveness of proposed method will be verified by comparing with conventional method. The simulation results will be carried out by using Matlab program.

• 전기학회논문지
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• 제59권6호
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• pp.1041-1045
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• 2010

Short-term electric load forecasting of power systems is essential for the power system stability and the efficient power system operation. An accurate load forecasting scheme improves the power system security and saves some economic losses in power system operations. Due to scarcity of the historical same type of holiday load data, most big electric load forecasting errors occur on load forecasting for the holidays. The fuzzy linear regression model has showed good accuracy for the load forecasting of the holidays. However, it is not good enough to forecast the load of the election day. The concept of the load variation rate for the load forecasting of the election day is introduced. The proposed algorithm shows its good accuracy in that the average percentage error for the short-term 24 hourly loads forecasting of the election days is 2.27%. The accuracy of the proposed 24 hourly loads forecasting of the election days is compared with the fuzzy linear regression method. The proposed method gives much better forecasting accuracy with overall average error of 2.27%, which improved about average error of 2% as compared to the fuzzy linear regression method.

• 농업과학연구
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• 제40권4호
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• pp.385-394
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• 2013

Short-term agricultural machinery rental system has been operated by agricultural extension organization of local government (agricultural technology center) and sponsored by Ministry of Agriculture, Food, and Rural Affairs, to improve utilization efficiency and save agricultural production cost through joint utilization of agricultural machinery. This study was conducted to analyze current status of the rental system operation and provide recommendations for future direction. Question survey was conducted for officers in charge of the rental system in the technology center, and strategic improvement was suggested through importance performance analysis (IPA). Survey results showed that 11 issues should be reformed or improved by 2015, which is not practically feasible. IPA analysis resulted that administration and manpower support, cooperation between federal and local organizations, and cooperation with other organizations should be focused for successful operation of the rental system. Issues that seem to happen after 2015 need to be handled as future research.

• 조명전기설비학회논문지
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• 제28권9호
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• pp.60-66
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• 2014

In case of DC railway, value of ESS(Energy Storage System) is already approved. Whereas AC railway system, there are a lot of differences such as system design and operation pattern. Therefore there is doubt about AC ESS usefulness. Especially, regenerative energy can return to the source. So in case of AC 25kV system, it is necessary to consider different operation algorithm compare to DC railway system. In this paper ESS which is installed in AC high-speed railway was introduced. Power consumption pattern of High speed trains were analyzed, proper storage material was reviewed and operation algorithm was suggested. Super capacitor and Battery was used with hybrid type. Super capacitor was used to handle short term energy movement because of its prompt response and battery was used to handle long term energy movement because of its high energy density. Also in case of operation algorithm, phase control method was upgraded compare to voltage magnitude detection method.

• 환경영향평가
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• 제21권1호
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• pp.185-199
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• 2012

Ecotourism has been attracting much attention as an example industry that can vitalize local economy markets and preserve natural resources. Implementation of 'Ecotourism Designation System' is under consideration to provide ecotourism products that can both emphasize the original meanings of ecotourism and ensure stronger trust from customers than ever before. This research introduced the direction, principles, subjects, and assessment indicators by subjects in terms of implementing the system and proposed fundamentals for both designation assignment and score calculation. In the face of implementing such a system in Korea, the investigation sought subjects whose target areas and programs are in need of examination. For assessment criteria by subjects, six assessment indicators were selected in the end for ecotourism sites, including: (1) the value of natural/ecological preservation (2) facility's ecological design (3) understanding both the environment and local culture (4) systems connecting local communities for cooperation (5) long/short term preservation and maintenance strategies/plans (6) willingness to further develop ecotourism and cooperative platform. In addition, seven assessment indicators were selected for program assignments, including: (1) the value of natural/ecological preservation (2) minimization of environmental effects (3) expansion of environmental understanding (4) sharing the local culture (5) vitalizing local connections and economical activities among communities (6) securing and maintaining professionality among human resources (7) odds of continuation, creativity, and aptness to improve programs. After considering the pros and cons of both categorizing system and yes/no system, implementation of categorizing system for the short term and yes/no for the long term were suggested, followed by additional suggestions of a score calculation system for each system. The official implementation of the 'Ecotourism Designation System' is scheduled for launch in 2013 after the trial operation in 2012. The assessment indicators and fundamentals suggested in this research, considering judgment, must be improved via systematic and practical methods through the trial operation.

• 대한산업공학회지
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• 제15권1호
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• pp.65-75
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• 1989

This study complements the previous studies on workload distribution problems in Flexible Manufacturing Systems. Specifically, we consider the problem in two perspectives, the long-range policy and the short and medium-term planning and control. The long-term loading policy focusses on identifying the optimal loading of the system characterized by either balanced loading or unique unbalanced loading for which a steepest ascent method is developed. These results are then applied to study the optimal medium and short-term planning and control problems, for which a truncated dynamic programming method is developed in order to obtain the optimal allocation of the given operation mix of part types to work stations.

• 농업과학연구
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• 제38권3호
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• pp.583-591
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• 2011

Status survey on short-term agricultural machinery rental business was conducted to provide basic data for effective and sustainable implementation of the rental system. Selected survey samples were 34 rental management institutions such as city and county level government offices and agricultural technology development centers, and Primary Agricultural Cooperatives. Survey was conducted through mailing of questionnaire papers and direct interviews with the officers in charge of the agricultural machinery short-term rental management. Number of agricultural machinery retained by the 34 management institutions for the machinery rental business was 3,699, and numbers of the machinery were 1630 for upland crops, 929 for rice, 542 for orchard farming, 274 for animal husbandry, and 324 for common use. Regarding size of warehouse for rental agricultural machinery, 50% of the institutes were less than 660 $m^2$, 26.5% were greater than 993 $m^2$, and 23.5% were between 663 and 990 $m^2$. Institutes maintaining machinery washing facilities were only 10 (29%) among the 34 rental management institutions. Agricultural machinery rental business was advertised to farmers by 91% of the institutes, and the methods were leaflet (35.2%), village broadcasting (26.5%), call-up education (23.6%), and TV and radio (14.7%). Major contents of the advertisement were rental procedure (52.9%), rental machinery (26.5%), and rental cost (20.6%).

• 한국산업융합학회 논문집
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• 제26권4_2호
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• pp.715-724
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• 2023

Solar energy forecasting is essential for (1) power system planning, management, and operation, requiring accurate predictions. It is crucial for (2) ensuring a continuous and sustainable power supply to customers and (3) optimizing the operation and control of renewable energy systems and the electricity market. Recently, research has been focusing on developing solar energy forecasting models that can provide daily plans for power usage and production and be verified in the electricity market. In these prediction models, various data, including solar energy generation and climate data, are chosen to be utilized in the forecasting process. The most commonly used climate data (such as temperature, relative humidity, precipitation, solar radiation, and wind speed) significantly influence the fluctuations in solar energy generation based on weather conditions. Therefore, this paper proposes a hybrid forecasting model by combining the strengths of the Prophet model and the GRU model, which exhibits excellent predictive performance. The forecasting periods for solar energy generation are tested in short-term (2 days, 7 days) and medium-term (15 days, 30 days) scenarios. The experimental results demonstrate that the proposed approach outperforms the conventional Prophet model by more than twice in terms of Root Mean Square Error (RMSE) and surpasses the modified GRU model by more than 1.5 times, showcasing superior performance.

• 전기학회논문지
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• 제60권12호
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• pp.2215-2220
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• 2011

The accurate short-term load forecasting is essential for the efficient power system operation and the system marginal price decision of the electricity market. So far, errors of load forecasting for Chuseok Holiday are very big compared with forecasting errors for the other special days. In order to improve the accuracy of load forecasting for Chuseok Holiday, selection of input data, the daily normalized load patterns and load forecasting model are investigated. The efficient data selection and daily normalized load pattern based on fuzzy linear regression model is proposed. The proposed load forecasting method for Chuseok Holiday is tested in recent 5 years from 2006 to 2010, and improved the accuracy of the load forecasting compared with the former research.