• Journal of the Korean Solar Energy Society
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• v.26 no.3
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• pp.53-62
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• 2006

Since the direct normal radiation and clear day are a main factor for designing any solar thermal and photovoltaic concentrating system, it is necessary to evaluate its characteristics all over the country. The work presented here are the investigation of direct normal radiation and clear day in Korea. The data utilized in the investigation consist of direct normal radiation collected for 14 years('90. 12${\sim}$2004. 12) and clear-day collected for 23 years($1982{\sim}2004$) at measuring stations across the country. The analysis shows that the annual-average daily direct normal radiation is 5.4 kWh/m2 and the annual-average total clear-day is 92.7 days in Korea. We also constructed the contour map of direct normal radiation and clear-day in Korea by interpolating actually measured data across the country.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.3
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• pp.289-297
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• 2001

From March 1998 to February 1999, we observed visibility and weather change in Dae Chung Bong and Kwon Keum Sung three times a day; at 10 Am, 1 PM and 4 PM. During research period (357 days for Kwon Keum Sung, 351 days for Dae Chung Bong), clear days were 185 days(52%) in Kwon Keum Sung and 149 days (43%) in Dae Chung Bong. Months that had many clear days in a year were December and January in both area. The rate of clear day to cloudy day in Sokcho downtown and Dae Chung Bong was 5 to 5, 4 to 6, respectively. The number of cloudy day in a year in Dae Chung Bong was 34days more than in Sokcho downtown. The visual distance in Kwon Keum Sung was 12.2km on the clear day, and 3.3km on the cloudy day. The yearly average was 7.9km. And we can see 8.9km farther on the clear day. The visual distance in Dae Chung Bong was 13.3km on the clear day, and 3.1km on the cloudy day. The yearly average was 8.1km. The visibility of clear day was 10.2km longer than that of cloudy day. The percentage to observe East Sea clearly was about 70% between December and January in both areas, and showed the highest visibility during research period. We observed Mt. Keumkang from 3 to 6 times in a month except rainy season. The yearly average visibility was 2%. If you go Mt. Serok except April, when there was yellow duet cloud from China, and rainy season (between the last of June and early of September), you can appreciate the most beautiful Mt. Sorak with Mt. Keumkang.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.13 no.1
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• pp.7-10
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• 1977

In estimates of horizontal radiation, its values are determined by correlations among the length of day, noon altitude of the sun, and cloud amount. During winter from 1971 to 1974 in Korea, its correlations are calculated by empirical method are $$Q_o=0.0124 H_cT_d at clear day and$$ $$ Q_s=0.0124 H_cT_d (1-0.0C4^1.3) at cloudy day.$$ here$ Q_o, Q_s, H_c, T_d, C $ are horizontal radiation at clear day, horizontal radiation at cloudy day, noon altitude of the sun, length of day, and cloud amount. In applications of this equation at 10 stations in Korea, errors are less than 10% when cloud amount are less than 7, and 1O~20% when cloud amount are more than 7. But, according to Laevastu equation in same case, errors are 50% closely.

• Journal of the Korean Solar Energy Society
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• v.25 no.3
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• pp.11-18
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• 2005

The Korea Institute of Energy Research(KIER) has begun collecting horizontal global insolation data since May, 1982 at different locations. Because of a poor reliability of existing data, KIER's new data will be extensively used by the solar system users as well as by research institutes. But the quality of solar insolation data is not always good. This reports on an attempt to identify systematic error in such data using clear-day analysis for data rehabilitation. Clear-day analysis is successful in uncovering solar insolation data of questionable quality. It is not proven that rehabilitation process can improve the quality of data for daily or monthly means, but it is suggested that the method can be used to improve the quality of data for monthly means of several years for use in many applications of solar energy planning. Earlier studies finding a maximum ETR of about 0.80 are confirmed.

• East Asian Journal of Business Economics (EAJBE)
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• v.2 no.1
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• pp.1-6
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• 2014

This research was about understanding challenges in managing a business start up. University of Kigali was used as a case study. It is domiciled in Rwanda. It was chosen because it is a recent university establishment and it provided a good source of information for this research. The issue that triggered this study was to understand the virtue of having clear separation of duties in new business start-ups. The findings from this study reveal that 100 percent of the respondents believe that clear separation of roles and clear communication between management, shareholders and Board of directors is vital for new businesses. From the Literature review, it was clear that a firm in its infancy has a lot of risks and it would not be a bad idea for the start for shareholders and Board of directors to give a helping hand in the day to day running of the business until its stabilization. Employees need to know the vision and mission of the business start-up and again, the managing director of a firm needs to work closely with the chairman Board of directors for effective driving of the firm into the right direction. The momentum in growth of University of Kigali is due to respect of the pillar of separation of duties in its hierarchical structure and for allowing a decentralized structure type of management for flourish.

• Journal of the Korean Solar Energy Society
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• v.25 no.1
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• pp.11-18
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• 2005

Since the direct normal insolation is a main factor for designing any solar thermal power system, it is necessary to evaluate its characteristics all over the country. We have begun collecting direct normal insolation data since December 1990 at 16 different locations and considerable effort has been made for constructing a standard value from measured data at each station. KIER(Korea Institute of Energy Research's new data will be extensively used by solar thermal concentrating system users or designers as well as by research institutes. From the results, we can conclude that 1) Yearly mean $5.4kWh/m^2/day$ of the direct normal insolation was evaluated for clear day all over 16 areas in Korea. 2) Clear day's direct normal insolation of spring and summer were $5.53kWh/m^2/day$ and $5.84kWh/m^2/day$, and for fall and winter their values were $5.3kWh/m^2/day$ and $4.94kWh/m^2/day$ respectively. So, spring and summer were higher, and fall and winter were lower than the yearly mean value.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.653-657
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• 2007

Since the direct normal insolation is a main factor for designing any solar thermal power system, it is necessary to evaluate its characteristics all over the country. We have begun collecting direct normal insolation data since December 1990 at 16 different locations and considerable effort has been made for constructing a standard value from measured data at each station. KIER(Korea Institute of Energy Research's new data will be extensively used by solar thermal concentrating system users or designers as well as by research institutes. From the results, we can conclude that 1) Yearly mean 5.41kWh/$m^2$/day of the direct normal insolation was evaluated for clear day all over 16 areas in Korea. 2) Clear day's direct normal insolation of spring and summer were 5.54kWh/$m^2$/day and 5.86kWh/$m^2$/day, and for fall and winter their values were 5.32kWh/$m^2$/day and 4.92kWh/$m^2$/day respectively. So, spring and summer were higher, and fall and winter were lower than the yearly mean value.

• Solar Energy
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• v.20 no.2
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• pp.31-42
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• 2000

Since the direct normal insolation is a main factor for designing any focusing solar system, it is necessary to evaluate its characteristics all over the country. We have begun collecting direct normal insolation data since December 1990 at 16 different locations and considerable effort has been made for constructing a standard value from measured data at each station. KIER(Korea Institute of Energy Research)'s new data will be extensively used by concentrating system users or designers as well as by research institutes. From the results, we can conclude that 1) Yearly mean $4,576kcal/m^2.day$ of the direct normal insolation was evaluated for clear day all over 16 areas in Korea. 2) Clear day's direct normal insolation of spring and summer were $4,710kcal/m^2.day$ and $4,960kcal/m^2.day$, and for fall and winter their values were $4,484kcal/m^2.day$ and $4,151kcal/m^2.day$ respectively. So, spring and summer were higher, and fall and winter were lower than the yearly mean value.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.2
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• pp.169-174
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• 1982

Light intensities under and above shading material were measured at different layers (upper, middle and lower layers) and lines (lst, 3rd and 5th lines) on clear and cloudy days in S-year-old ginseng plant populations. Rates of photosynthesis and respiration were also measured in field. Light intensities of the 1st lines at upper and lower layers were relatively high as compared with the 3rd and the 5th lines, and there were no remarkable difference between the 3rd and the 5th line. But in middle layer, the light intensity of each line differed considerably. As compared with fair and clear day, the day of clear but much diffuse light showed high light intensity under shading. Relative light intensity was higher on cloudy day than on clear day. There were notable differences of photosynthetic rates among the lines and the rearest lines exhibited the lowest rates. But it was not considered that even the front plants demonstrated the maximum photosynthetic capacity.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.262-265
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• 2009

This study was carried out to evaluate the clear day operating performances for the decentralized desalination system with the solar thermal system and the photovoltaic power system. In a clear day, we used a solar thermal system as heat source of the single-stage fresh water generator with plate-type heat exchangers and a photovoltaic power system as electric source for hydraulic pumps. The demonstration system generation was designed and installed at Jeju-island in 2006. The system was comprised of the desalination unit with daily fresh water capacity designed as $2m^3$, a $120m^3$ evacuated tubular solar collector to supply the heat, a $6m^3$ heat storage tank, and a 5.2kW photovoltaic power generation to supply the electricity of hydraulic pumps for the heat medium fluids. In a clear day, solar irradiance daily averaged was measured $518W/m^3$, the daily fresh water yield showed that about 565 liter.