• The Korean Journal of Applied Statistics
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• v.30 no.6
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• pp.1005-1013
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• 2017

In this paper, we investigate the performances of time series models to forecast irradiance that consider weather variables such as temperature, humidity, cloud cover and Global Horizontal Irradiance. We first introduce the time series models and show that regression ARIMAX has the best performance with other models such as ARIMA and multiple regression models.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.409-412
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• 2009

In this research, the intensity of solar energy, which was injected to the different angle plane every hour day by day, was technically documented and quantitatively analyzed through actual observations. In order to group every days into days with similar intensity, graph was drawn with respect to time for every day and each area value under the curve was calculated. Then, the search for grouped days having similar intensity curve patterns was carried out and the optimum incident angle of absorber plate was derived to maximize the efficiency of solar energy systems.

• Solar Energy
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• v.16 no.2
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• pp.49-63
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• 1996

Site elavation is one of the major factors which is influencing the incoming insolation. Because nonpermanent gases like ozone, water vapor are unmixed components of the atmosphere and their concentrations are function of height, the site elevation effects the relative proportion of the atmospheric constituents. We have measured solar radiation on Sobaek(1,350m) and in Poonggi area(280m). These values were compared to investigate the their charateristics and the potential for the solar utilization as an alternative energy for both high altitude area and low altitude area. From the results, we conclude that 1) Yearly mean 4,093 $kcal/m^2$. day of the horizontal global radiation in Mt. Sobaek was evaluated for clear day. 2) Insolation on Mt. Sobaek is $6{\sim}7%$ higher than Poonggi area during summer and winter seasons. 3) A significant difference of atomospheric clearness index is observed between Mt. Sobaek and Poonggi area at the same latitude.

• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.249-255
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• 2010

Since the 1990's, a number of ULF geomagnetic disturbance associated with earthquake occurrences have actively been reported, and polarization analysis of geomagnetic fields becomes one of potential candidates to be capable of predicting short-term earthquake. This study develops the modified polarization analysis method based on the previous studies, and analyzes three-component geomagnetic fields obtained at Cheongyang geomagnetic observatory using the developed method. A daily polarization value (the ratio of spectral power of horizontal and vertical geomagnetic field) is calculated with a focus on the 0.01 Hz band, which is known to be the most sensitive to seismogenic ULF radiation. We analyze a total of 10 months of geomagnetic data obtained at Cheongyang observatory, and compare the polarization values with the Kp index and the earthquake occurred in the analysis period. The results show that there is little correlation between the temporal variations of polarization values and Kp index, but remarkable increases in polarization values are identified which are associated with two earthquakes. Comparison the polarization values obtained at Cheongyang and Kanoya observatory indicates that the increases of polarization values at Cheongyang might be due to not global geomagnetic induction but the locally occurred earthquakes. Furthermore, these features are clearly shown in normalized polarization values, which take account in the statistical characteristics of each geomagnetic field. On the basis of these results, polarization analysis can be used as promising tool for monitoring the earthquake-precursory phenomenon.